Patent Application
20130201806
The present invention relates to an information recording medium, such as an optical disc of a multilayer type or multilayer recording type, an information recording apparatus and method for recording information onto the information recording medium, and an information reproducing apparatus and method for reproducing the information from the information recording medium.
In this type of information recording medium, a plurality of or multiple recording layers are laminated on a single guide layer in which tracks are formed in advance, and the guide layer is used to perform recording and reproduction in each recording layer (e.g. refer to patent documents 1 to 3).
Specifically, at the time of the recording and the reproduction, a first light beam for tracking (e.g. a guiding light beam or a servo light beam including red laser as in a DVD) is irradiated and focused on the guide layer through the recording layers. This enables the tracking for each recording layer. In other words, this enables focus servo for the guide layer and tracking servo using the tracks formed in advance in the guide layer.
In parallel with such a tracking operation, a second beam for information recording and reproduction in which a positional relation with the first beam is fixed or known (e.g. a main light beam including blue laser as in a Blu-ray) is irradiated typically in a form of concentrically overlapping the first beam by using the same optical pickup or through the same objective lens or in similar manners and is focused on one recording layer which is a recording or reproduction target. This enables the information recording and reproduction in each recording layer. In other words, this enables the focus servo for each recording layer and information writing or reading.
In addition, the recording and the reproduction of this type of information recording medium are performed while so-called “tilt correction” is performed on the optical pickup by a correction mechanism for correcting a disc tilt or simply tilt (typically, a slope or inclination of an optical disc surface). More generally, not only the tilt correction but also various processing, such as eccentricity correction of a disc, inclination correction of a disc surface, aberration correction of an optical system, phase difference correction of a light beam, distortion correction, light absorption correction, and setting of a strategy, are performed while the recording and the reproduction are performed.
However, in a technology disclosed in the patent documents, if a track pitch is narrowed with respect to a diameter of the first light beam to the extent that the first light beam is simultaneously irradiated on a plurality of tracks adjacent to each other in the guide layer, it is hard to perform a practically accurate tracking pull-in operation or a track jump operation in desired timing to a desired track. Alternatively, even if control information (e.g. servo marks, address information, etc.) is written in the tracks, it is hard to improve the track pitch and a recording linear density (a linear recording density, a pit pitch, or an information transfer rate) which allows the recording or reproduction in the recording layer, to the extent that it can be called “high-density recording”, which is an intended purpose in the information recording medium of the multilayer type.
In particular, if a zone constant angular velocity (CAV) method is adopted, an angular velocity increases in each of zones having different radial direction positions. Therefore, an arrangement relation of control information recorded in tracks in a guide layer, or an arrangement relation of patterns for detecting tilt errors, become arbitrary depending on a radial position.
Moreover, if concentric tracks are adopted, track jumps are particularly frequently performed. Alternatively, even if a spiral track is adopted, the track jumps are also performed, as occasion demands. Thus, it becomes extremely difficult to correspond to a high-density track pitch and a recording linear density for realizing high-density recording, as described above, regardless of the radial position. In other words, if the zone CAV method is adopted in a multilayer type information recording medium, there is such a technical problem that it is practically extremely difficult to perform the tracking servo, and further to accurately perform the track jump on the desired track and to accurately perform tracking servo pull-in, with high accuracy or with high resolution that can correspond to the high-density recording, which is an original purpose of the multilayer type.
Moreover, in particular, in the case of a zone CAV multilayer type optical disc, it is necessary to appropriately change various control in each layer and each zone. Thus, it is extremely important to perform a particular type of processing, such as tilt correction, with respect to each recording layer and each zone, as occasion demands, and particularly to perform the track jump on the desired track and the tracking servo pull-in with high reliability. Furthermore, it is more important to do so for the high-density recording and the high transfer rate.
In view of the aforementioned problems, it is therefore an object of the present invention to provide an information recording medium of a multilayer type which enables high-accuracy tracking servo and a track jump while increasing information recording density, an information recording apparatus and method for recording information onto such an information recording medium, and an information reproducing apparatus and method for reproducing the information from such an information recording medium.
In order to solve the above object, an information recording medium of the present invention is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open.
In order to solve the above object, a first information recording apparatus of the present invention is an information recording apparatus for recording data onto an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information recording apparatus is provided with: a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data recording on one recording layer out of the plurality of recording layers; an information obtaining device for receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a first pull-in controlling device for controlling start or continuation of a pull-in operation of pulling in the tracking servo on the basis of one type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open; a second pull-in controlling device for controlling continuation or end of the pull-in operation on the basis of another type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open or is being pulled in; a tracking servo device for controlling the light irradiating device to perform the tracking servo on a desired track out of the plurality of tracks on the basis of the obtained guide information; and a data recording control device for controlling the light irradiating device to record the data by irradiating and focusing the second light beam on the one recording layer in a servo-closed state in which the tracking servo is performed.
In order to solve the above object, a second information recording apparatus of the present invention is an information recording apparatus for recording data onto an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information recording apparatus is provided with: a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data recording on one recording layer out of the plurality of recording layers; an information obtaining device for receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a jump controlling device for controlling a track jump associated with the tracks on the basis of one type of the detected predetermined pattern in the plurality of specific areas in a servo-closed state in which the tracking servo is performed; and a data recording control device for controlling the light irradiating device to record the data by searching for a desired position on the plurality of tracks on the basis of the obtained guide information when the track jump is performed and by irradiating and focusing the second light beam on the one recording layer in the servo-closed state.
In order to solve the above object, a first information recording method of the present invention is an information recording method of recording data onto an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information recording method recording the data by using a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data recording on one recording layer out of the plurality of recording layers, the information recording method is provided with: an information obtaining process of receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a first pull-in controlling process of controlling start or continuation of a pull-in operation of pulling in the tracking servo on the basis of one type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open; a second pull-in controlling process of controlling continuation or end of the pull-in operation on the basis of another type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open or is being pulled in; a tracking servo process of controlling the light irradiating device to perform the tracking servo on a desired track out of the plurality of tracks on the basis of the obtained guide information; and a data recording control process of controlling the light irradiating device to record the data by irradiating and focusing the second light beam on the one recording layer in a servo-closed state in which the tracking servo is performed.
In order to solve the above object, a second information recording method of the present invention is an information recording method of recording data onto an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information recording method recording the data by using a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data recording on one recording layer out of the plurality of recording layers, the information recording method is provided with: an information obtaining process of receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a jump controlling process of controlling a track jump associated with the tracks on the basis of one type of the detected predetermined pattern in the plurality of specific areas in a servo-closed state in which the tracking servo is performed; and a data recording control process of controlling the light irradiating device to record the data by searching for a desired position on the plurality of tracks on the basis of the obtained guide information when the track jump is performed and by irradiating and focusing the second light beam on the one recording layer in the servo-closed state.
In order to solve the above object, a first information reproducing apparatus of the present invention is an information reproducing apparatus for reproducing data from an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information reproducing apparatus is provided with: a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data reproduction on one recording layer out of the plurality of recording layers; an information obtaining device for receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a first pull-in controlling device for controlling start or continuation of a pull-in operation of pulling in the tracking servo on the basis of one type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open; a second pull-in controlling device for controlling continuation or end of the pull-in operation on the basis of another type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open or is being pulled in; a tracking servo device for controlling the light irradiating device to perform the tracking servo on a desired track out of the plurality of tracks on the basis of the obtained guide information; and a data obtaining device for receiving second light based on the irradiated and focused second light beam from the one recording layer and obtaining the data on the basis of the received second light in a servo-closed state in which the tracking servo is performed.
In order to solve the above object, a second information reproducing apparatus of the present invention is an information reproducing apparatus for reproducing data from an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information reproducing apparatus is provided with: a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data reproduction on one recording layer out of the plurality of recording layers; an information obtaining device for receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a jump controlling device for controlling a track jump associated with the tracks on the basis of one type of the detected predetermined pattern in the plurality of specific areas in a servo-closed state in which the tracking servo is performed; and a data obtaining device for searching for a desired position on the plurality of tracks on the basis of the obtained guide information when the track jump is performed, receiving second light based on the irradiated and focused second light beam from the one recording layer, and obtaining the data on the basis of the received second light in the servo-closed state.
In order to solve the above object, a first information reproducing method of the present invention is an information reproducing method of reproducing data from an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information reproducing method reproducing the data by using a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data reproduction on one recording layer out of the plurality of recording layers, the information reproducing method is provided with: an information obtaining process of receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a first pull-in controlling process of controlling start or continuation of a pull-in operation of pulling in the tracking servo on the basis of one type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open; a second pull-in controlling process of controlling continuation or end of the pull-in operation on the basis of another type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open or is being pulled in; a tracking servo process of controlling the light irradiating device to perform the tracking servo on a desired track out of the plurality of tracks on the basis of the obtained guide information; and a data obtaining process of receiving second light based on the irradiated and focused second light beam from the one recording layer and obtaining the data on the basis of the received second light in a servo-closed state in which the tracking servo is performed.
In order to solve the above object, a second information reproducing method of the present invention is an information reproducing method of reproducing data from an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information reproducing method reproducing the data by using a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data reproduction on one recording layer out of the plurality of recording layers, the information reproducing method is provided with: an information obtaining process of receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a jump controlling process of controlling a track jump associated with the tracks on the basis of one type of the detected predetermined pattern in the plurality of specific areas in a servo-closed state in which the tracking servo is performed; and a data obtaining process of searching for a desired position on the plurality of tracks on the basis of the obtained guide information when the track jump is performed, receiving second light based on the irradiated and focused second light beam from the one recording layer, and obtaining the data on the basis of the received second light in the servo-closed state.
The operation and other advantages of the present invention will become more apparent from embodiments explained below.
Hereinafter, as the best mode for carrying out the invention, embodiments associated with a driving apparatus will be explained in order.
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In order to solve the above object, an information recording medium of the present embodiment is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open.
According to the information recording medium in the embodiment, typically, by using the concentric or spiral tracks provided for the guide layer for guidance or tracking, it is possible to optically record information into a desired recording layer out of the plurality of recording layers laminated on or under the guide layer, for example, in the zone constant angular velocity (CAV) method along the tracks. Moreover, by using or without using the tracks for guidance, it is possible to optically reproduce the information from the desired recording layer which is already recorded, for example, in the zone CAV method.
Here, the “guide layer” typically means a layer for guiding or leading to a position in a recording surface of each recording layer (i.e. a position in the radial direction and a position in the track direction along the recording surface) by using a first light beam for guidance or tracking (hereinafter simply referred to as a “first light beam”), at least in information recording or writing into each recording layer. The “guide layer” is typically a layer in which the tracks, which are configured to generate a tracking error signal (or a wobble signal as a basis thereof, a pre-pit signal, or the like), are physically formed in advance.
Moreover, the “tracks” formed in the guide layer mean courses or paths which are tracked or followed by the first light beam. Typically, for example, the tracks are wobbled. In addition to or instead of this, the tracks are physically formed in advance in the guide layer or on the guide layer, as groove tracks or land tracks in which pits are formed. Incidentally, information tracks formed after the recording in the recording layer are clearly distinguished from the “tracks” formed in advance herein, in that the information tracks are established as the arrangement or alignment of information pits recorded in the recording surface which originally does not have any tracks.
At each of positions which will make the information tracks after the recording in the desired recording layer and which correspond to respective positions of the first light beam on the tracks in the guide layer guided as described above, typically, the information recording is performed by a second light beam for information recording or information writing (hereinafter simply referred to as a “second light beam”).
Incidentally, typically, it is enough to provide one guide layer for all the recording layers; however, a plurality of guide layers, such as two layers, may be provided and each of them may be used as occasion demands, or the roles thereof may be divided. In any case, the guide layer and the plurality of recording layers are provided, as layers which are separate from each other.
The plurality of recording layers are configured such that information can be recorded or further reproduced independently in each of the recording layers, such as, for example, 16 layers. Each of the plurality of recording layers preferably has as a simple structure as possible, such as straight grooves or straight lands or a mirror surface, in an unrecorded state. That is because it is preferable in manufacturing that alignment between the plurality of recording layers and alignment between the recording layers and the guide layer are almost or practically completely unnecessary. The structure of the recording layers is configured to perform the recording in various recording methods in which each of transmittance and reflectance in each recording layer is set to be included in a predetermined range, so that the light beam reaches one recording layer on the rear side or the guide layer, viewed from the irradiation side of the light beam.
More specifically, in the information recording, for example, the tracking error signal (or the wobble signal as the basis thereof and additionally the pre-pit signal) can be detected from reflected light obtained when the first light beam (e.g. red laser for forming a light spot with a relatively large diameter) is focused on the tracks which exist in the guide layer. In accordance with the tracking error signal, the tracking or the tracking servo can be performed as one type of a guide operation. The information recording is performed by focusing the second light beam (e.g. blue laser for generating alight spot with a relatively small diameter) on the desired recording layer on the upper layer or lower layer side of the tracks in a state in which the tracking is performed or the tracking servo is closed. In other words, in-plane positioning for the information recording is performed in the desired recording layer which is another layer in which the tracks or the like do not exist (e.g. in a mirror-surface state), on the basis of the positions of the tracks formed in advance in the guide layer. (Incidentally, focus is separately performed in focusing the light.)
Here, if an optical system for irradiating the first and second light beams is fixed in an optical pickup or the like, a positional relation between the light spots formed by the light beams is also fixed. Thus, performing the guide operation, such as the tracking servo, for the position of the first light beam (i.e. the position of the light spot on the tracks formed by the first light beam) means performing the guide operation even for the second light beam (i.e. the position of the light spot in the recording surface formed by the second light beam) with reproducibility. In other words, by using the first light beam on the tracks which exist in advance, it is possible to track or guide the second light beam in the recording surface in which the tracks do not exist in advance.
If such a recording method is adopted, there is almost or practically no need to perform the alignment in a direction along the recording surface between the tracks, between the guide layer and each of the recording layers which are laminated mutually, or between the plurality of recording layers. This is extremely useful in manufacturing.
On the other hand, in the information reproduction, in the same manner, the tracks may be used for guidance. Alternatively, in the information reproduction, the reproduction can be performed by performing the tracking operation on the information tracks after the recording, without using the guide layer for guidance (typically for tracking), by following the information which is already written in the recording layer.
On the tracks formed in the guide layer, there are disposed the plurality of guide areas each of which has the physical structure for carrying the guide information. Here, the “guide information” is information for guiding or leading or following the first light beam, and typically information for optically generating the tracking error signal (or the wobble signal as the basis thereof and additionally the pre-pit signal). Moreover, the guide information can be referred to as “mark information”, since the guide information becomes a mark for positioning the light beam for tracking.
The physical structure for carrying the guide information as described above is typically realized by the arrangement or alignment or the like of pre-pits on a surface without the grooves and lands (e.g. a mirror surface), a wobble and partial-notch structure, and a wobble and pre-pit structure (i.e. land pre-pits, groove pre-pits, etc.) formed on the side walls of or in the inside or outside of the groove tracks or land tracks. Here, the “physical structure” is different from a logical structure, i.e. a conceptual or virtual structure simply established by data, but means a structure which physically exists. The physical structure is already formed on the guide in the completion of the information recording medium.
As a result of studies by the present inventors, it has been found that a special purpose of allowing the guide operation to be performed, such as, for example, performing the tracking in a predetermined band, can be achieved even without continuously forming special mechanisms for detecting the guide information in the track direction, as in tracks of a prior or existing optical disc, even if it is necessary to allow the detection of the guide information in any track. In other words, as long as the arrangement interval (i.e. arrangement pitch) of the guide information corresponding to a time interval at which the guide information is detected is set to be less than a distance minimum required to enable the guide operation (e.g. to be less than or equal to the longest distance that allows the tracking servo to operate in the predetermined band). At the same time, regarding the plurality of tracks which are adjacent to each other, it has been found that the aforementioned purpose can be achieved even if such special mechanisms are not arranged in a respective plurality of positions or areas aligned in the radial direction, i.e. even if such special mechanism area not arranged (or aligned) regularly in one line in the radial direction.
Thus, in the present invention, the plurality of guide areas are mutually arranged discretely at arrangement intervals (i.e. arrangement pitch) of the predetermined distance or less which is set in advance in the track direction along the tracks (in other words, a tangential direction of the tracks) which are spiral or concentric. Here, the “predetermined distance” is typically a distance which is shorter by some margin than the longest distance that allows the function of the guidance or the guide operation, which is the tracking or the tracking operation in the predetermined band (e.g. the longest distance that allows the continuous or continual generation of a tracking signal at a frequency which enables the tracking operation to be performed stably in the predetermined band). Moreover, the “predetermined band” means a band unique to a data format or data standard in which the tracking operation is performed and which is determined by a relation with a band used in the information recording.
The predetermined distance as described above may be set by obtaining a limiting distance in which the guide operation (typically, the tracking operation in the predetermined band) functions and by determining an appropriate margin, with respect to the guide layer of a specific information recording medium, by experiments, experiences, simulations, or the like in advance. If the guide areas are discretely arranged at arrangement intervals (i.e. arrangement pitch) longer than the predetermined distance, then, the tracking error signal cannot be generated at a frequency which allows the stable tracking servo in the predetermined band; namely, the stable guide operation cannot be performed.
Incidentally, “discretely” means that the guide areas are not mutually continuous, viewed planarly on the recording surface of each recording layer and that there are an another planar area between the guide areas, such as the mirror surface, buffer areas, and areas other than the guide areas.
The plurality of guide areas are shifted between the plurality of tracks throughout the plurality of tracks which are adjacent to each other in the radial direction crossing the tracks (i.e. the direction of the radius). Here, the expression of “throughout the plurality of tracks” means throughout or straddling two or more tracks which are adjacent to each other, including areas occupying gaps of the tracks, viewed planarly on the recording surface of each recording layer. Moreover, the expression of “shifted between the plurality of tracks in the radial direction” means that the plurality of tracks are not in the same phase (e.g. angle on a disc), or positions corresponding to the same phase (e.g. angular positions on the disc) in the radial direction (i.e. the direction of the radius), or not on the same radius. At this time, the plurality of guide areas arranged respectively adjacently in the radial direction do not need to be separated completely (i.e. do not need to have gaps therebetween). Typically, it is enough to shift the phase in the radial direction to the extent that the light beam for tracking servo in the information recording or reproduction does not cover the plurality of tracks simultaneously (e.g. throughout five tracks). Alternatively, it is enough to shift the phase to the extent that the signal and information which can be read from the plurality of guide areas by the light beam can be distinguished from each other.
Thus, even if a track density is increased until the spot of the light beam straddles or covers two or more tracks or track portions which are adjacent to each other (e.g. until the spot covers five tracks), as long as the guide areas are shifted as described above in response to the increased track density, it is possible to avoid a situation in which the guide information cannot be detected due to the overlap of the guide information in both the track direction and the radial direction (or due to an influence of a signal component from another guide area as noise), i.e. due to the crosstalk of the detected guide information. As described above, even if the track density is increased, the guidance or the tracking can be performed, and typically, the original function of generating the tracking signal as the guide layer is guaranteed.
Therefore, it is possible to stably and continuously generate the guide information, such as the tracking error signal or the wobble signal as the basis thereof and additionally the pre-pit signal, for example, by sampling a push-pull signal obtained from the reflected light caused by the first light beam or the like, while narrowing the track pitch with respect to the diameter of the first light beam to the extent that the plurality of tracks which are adjacent to each other in the guide layer are simultaneously irradiated with the first light beam. In other words, it is possible to perform the stable guide operation, such as the tracking operation, in the predetermined band. Alternatively, if the guide information includes information for control (e.g. a servo mark, address information, etc.), this can be certainly read as information based on the reflected light caused by the first light beam or the like. In other words, it is possible to stably obtain pre-format information.
This works extremely useful, particularly in cases where the first light beam (e.g. red laser) has a larger beam diameter than that of the second light beam (e.g. blue laser) and in cases where a recording density in the information recording into one recording layer is increased nearly to the limit by effectively using the light spot of the second light beam which is relatively small (i.e. in accordance with the small size). In other words, if narrow-pitch tracks corresponding to a narrow-pitch recording area which will make the tracks after the recording in the recording layer are formed in advance in the guide layer, the light spot of the first light beam, which is naturally larger than such tracks, has a technical characteristic of being simultaneously irradiated throughout the plurality of tracks (e.g. many tracks such as five tracks). Thus, it is necessary to perform the guide operation, such as the tracking operation, corresponding to a narrow-pitch recording layer by using the first light beam for forming the relatively large light spot.
Incidentally, even in cases where the first light beam has a smaller beam diameter than that of the second light beam, or even in cases where their diameters are almost or completely the same, as long as the guide operation is appropriately performed when the diameter of the light beam is larger than the track pitch, the unique configuration of the embodiment as described above provides a proper operational effect.
As described above, regarding the tracks for guidance, the pitch thereof can be set as a narrow pitch (can be set on the same level with a narrow pitch of the information tracks which are suitable for the beam diameter of the second light beam and which are established by the recording in the recording layer) (i.e. a narrow pitch unsuitable for the first light beam) without damaging the guiding function, such as enabling the tracking servo in the predetermined band or reading the pre-format information.
In addition, in particular, since, for example, the zone CAV method is adopted, an angular velocity increases toward a zone, a writing position or a reading position on an inner circumferential side (in other words, the angular velocity decreases toward an outer circumferential side). Thus, for example, an arrangement relation of the guide information recorded in advance in the tracks in the guide layer is arbitrary in accordance with a radial position. For example, it is basically impossible to adopt the arrangement of aligning a particular length of information throughout the plurality of tracks in the radial direction, which is possible in a constant angular velocity (CAV) method. Then, if no measure is taken, for example, in the zone CAV method, the track portion inside the light spot is arbitrary in accordance with the radial position (i.e. even the particular length of information is shifted in the track direction in accordance with the position in the radial direction in any cases) in cases where the first light beam forms the light spot throughout the plurality of tracks, and it is extremely unstable to obtain the guide information in accordance with the radial position.
However, the guide areas are shifted between the plurality of tracks in the radial direction, consciously or positively as described above. Thus, regardless of the position in the radial direction (i.e. regardless of whether to be closer to the inner circumference or the outer circumference), it is possible to stably perform the guide operation, such as the tracking servo, in the predetermined band, in response to a high-density track pitch and a recording linear density for realizing high-density recording. Conversely, if the predetermined distance and the way to shift are defined in advance in accordance with the radial position on the premise that it is, for example, in the zone CAV method, then, there is no problem, for example, even in the zone CAV method.
Moreover, particularly in the embodiment, on the tracks, the plurality of specific areas, each of which has the predetermined pattern, are arranged, separately from the plurality of guide areas as described above. At least one portion of the plurality of specific areas are respectively arranged in the same phase from the inner circumference to the outer circumference in the radial direction such that the predetermined pattern owned by the specific area can be detected in the state in which the tracking servo is open, at least in the recording (or additionally, in the reproduction).
Namely, the “predetermined pattern” means a pattern that can be detected even in the state in which the tracking servo is open, in the condition that the plurality of specific areas are respectively arranged in the same phase from the inner circumference to the outer circumference in the radial direction. The predetermined pattern typically includes a portion provided with the groove track or the land track formed one by one on the plurality of tracks which are adjacent to each other in the radial direction.
In other words, the “predetermined pattern that can be detected even in the state in which the tracking servo is open” is formed in areas whose start positions are substantially aligned in the radial direction and whose end positions are substantially aligned in the radial direction at least in a certain range of area, such as, for example, each zone in the zone CAV. Moreover, one type of pattern (e.g. a first SYNC pattern) of the predetermined pattern is formed in a physical shape, such as marks, pits, or partial grooves whose start positions and end positions are substantially aligned in the radial direction and which are provided in at least one section or more. At the same time, the physical shape is formed in at least one track of adjacent tracks included in the beam diameter of the first light beam determined from λ/NA (i.e. wavelength/numerical aperture). Moreover, another type of pattern (e.g. a second SYNC pattern) having a different length along the track from that of the one type of pattern is formed on the end position side of the areas, in the physical shape in the same manner as the one type of pattern. The predetermined pattern that can be detected even in the state in which the tracking servo is open” typically means such a pattern.
Moreover, “in the same phase” or “being arranged in the same phase” means along the same radius or being arranged along the same radius without spacing out in the track direction. Thus, this in effect includes not only the case of literally being completely on the same radius or being arranged completely in line on the same radius, but also, for example, the case of being arranged with overlap of at least a slight width along the same radius (i.e. a width in the track direction) by a zone unit of the zone CAV, or the case of being arranged with overlap of a certain width, regardless of a slight shift in the track direction. Moreover, the “same phase from the inner circumference to the outer circumference in the radial direction” typically means an entire area from the innermost circumference to the outermost circumference, but may in effect exclude the innermost circumference, the outermost circumference, or some portion in the middle. In other words, it is possible to properly obtain the operation and effects of the present invention of enabling the tracking servo pull-in and the track jump described below, in a portion excluding some portion.
Moreover, regarding the plurality of specific areas, at least in one portion or a body portion thereof (e.g. a body portion 24-2 of a specific area 24 in an example described later), arrangement is performed in the same phase, i.e. on the plurality of tracks which cross the same radius and which are adjacent to each other, typically without skipping any track, as opposed to the case of the plurality of guide areas. In other words, the plurality of specific areas are typically arranged one by one (without skipping any track) on the plurality of tracks in the same phase. As described above, the expression of “being respectively arranged in the same phase” typically means “being arranged one by one on the plurality of tracks which are adjacent to each other in the same phase”.
Here, in general, in order to start, continue, or stop the tracking servo pull-in operation, it is necessary to detect a signal indicating that a light irradiation position (i.e. a writing position or a reading position of an optical pickup) crosses the plurality of tracks (e.g. a “zero cross signal”) even in the state in which the tracking servo is open. Even if the track jump is performed, in the same manner, it is necessary to detect the signal indicative of crossing the tracks. For example, even if it is tried to detect the signal indicative of crossing the tracks in the plurality of guide areas discretely arranged, basically, the signal can be obtained only at a ratio of one to several tracks because the grooves and the lands exist on the same radius at the ratio of one to several tracks (e.g. a ratio of one to seven tracks). In other words, in the arrangement as in the plurality of guide areas arranged with gaps in the radial direction, it is quite hard to perform the tracking servo pull-in operation and the track jump.
In the embodiment, however, the plurality of specific areas, each having the predetermined pattern, are arranged, as described above. Thus, if the predetermined pattern, which occupies at least one portion of the specific areas, is detected by displacing the light irradiation position in the radial direction so as to be displaced along the plurality of specific areas when the tracking servo pull-in is performed in the recording or reproduction of the information recording medium, then, it is possible to start, continue, and stop the tracking servo pull-in operation without any problem. In other words, in the relation with the tracking servo pull-in operation, if one portion of the specific areas is configured such that there is one or less groove or the like included in the beam diameter, then, a sufficient zero cross signal group to perform the servo pull-in operation can be obtained. Alternatively, if the predetermined pattern, which occupies at least one portion of the specific areas, is detected even in the state in which the tracking servo is closed, by displacing the light irradiation position in the radial direction so as to be displaced along the plurality of specific areas when the track jump is performed in the recording or reproduction of the information recording medium, then, it is possible to perform the track jump without any problem. Even in this case, in the relation with the track jump, if one portion of the specific areas is configured such that there is one or less groove or the like included in the beam diameter, then, a sufficient zero cross signal group to perform the track jump can be obtained. On the other hand, after the tracking servo pull-in operation is completed, or after the track jump is performed, or in the state in which the tracking servo remains closed, the tracking may be performed by using the guide areas other than the specific areas, as described above.
As a result, it is possible to improve the track pitch and the recording linear density (e.g. a linear recording density, a pit pitch, or an information transfer rate (i.e. recording linear density×moving speed)) which allow the recording or reproduction in the recording layer to the extent that it can be called the “high-density recording”, which is an intended purpose in the information recording medium of the multilayer type, while performing the tracking servo pull-in operation and the track jump operation by using the specific areas, as occasion demands, and while performing the tracking operation by using the guide areas, as occasion demands.
<2>
In an another aspect of the information recording medium of the present embodiment, the predetermined pattern is physically formed in the guide layer by combining grooves and lands in a predetermined rule.
According to this aspect, the predetermined pattern is disposed in the same phase, as a combination of the grooves and lands in the predetermined rule, at least in one portion of the predetermined pattern. Here, the “predetermined rule” is a rule or regulation set in advance as for the combination of the grooves and the lands, such as, for example, alternately arranging the grooves and the lands with a constant length or a regulated length in the track direction, and may include a rule as for notches, wobbles, and the like. If one portion of the specific areas is configured such that there is one or less groove or the like included in the beam diameter, then, a predetermined zero cross signal group can be obtained.
<3>
In an another aspect of the information recording medium of the present embodiment, the predetermined pattern has at least one of a wobble and pre-pit structure and a wobble and partial notch structure.
By virtue of such a configuration, the predetermined pattern in each of the specific areas has the physical structure including at least one of the wobble and pre-pit structure and the wobble and partial notch structure for carrying the guide information for guidance. Here, the “wobble and pre-pit structure” means a structure in which the wobbles and wobbled groove or land tracks are formed and in which the pre-pits are formed in the grooves or lands. Moreover, the “pre-pits” are convex or concave pits or phase pits formed to have a narrower width than a groove width or land width, on the tracks which are in or on the grooves or on or in the lands. In other words, the pre-pits may be land pre-pits or groove pre-pits.
On the other hand, the “wobble and partial-notch structure” means a structure in which the wobbles and the wobbled groove or land tracks are formed and in which notches equivalent with the groove width or land width are formed in the grooves or lands. There are listed a case where one portion of the land which exists between the adjacent grooves is notched, a case where one portion of the groove which exists between the adjacent lands is notched, and a case of a combination thereof. In other words, the physical structure may be configured to include broad-sense pre-pits which are the partial notches. Moreover, the broad-sense pre-pits may be broad-sense land pre-pits or broad-sense groove pre-pits. Furthermore, in addition to such a structure, the aforementioned narrow-sense pre-pits (i.e. pre-pits without the partial notch structure) can be formed together.
As described above, the tracks are established in advance in the guide layer as the groove tracks or land tracks which are wobbled and in which the pits are formed, or as the groove tracks or land tracks in which one portion of the lands or grooves is notched. Thus, the establishment is relatively easy, and eventually, the guide operation with high reliability and stability becomes possible.
Incidentally, the grooves and the lands which form the predetermined pattern may be at least partially straight grooves and straight lands. Moreover, pits, notches, and the like may be added to the straight grooves and the straight lands. The “straight groove or straight land” means a simple straight groove or a land between the grooves in which wobbles and pits and the like are not formed. Incidentally, the groove and the land are relatively uneven, and either can be concave or convex, as viewed in a direction of irradiating the first and second light beams. For example, a concavity based on a body substrate which constitutes the information recording medium is the groove, and a convexity is the land. In this case, the groove may be convex and the land may be concave, as viewed in the direction of irradiating the first and second light beams. Moreover, the “mirror surface” on which neither the groove tracks nor the land tracks are formed, means a plain surface in which information is not particularly embedded and is a surface with highest optical reflectance in the guide layer.
<4>
In an aspect related to the combination of the groove and the land as described above, the predetermined pattern comprises (i) a first SYNC pattern, (ii) a body portion having a combination of the grooves and the lands according to the predetermined rule, and (iii) a second SYNC pattern which is different from the first SYNC pattern, which are arranged along the track direction.
By virtue of such a configuration, for example, the start of the body portion can be detected in advance by using the first SYNC pattern in the recording or in the reproduction. And by performing this, it is possible to start or continue the tracking servo pull-in operation or the track jump operation, which are the important operations, in the condition that everything is ready, in the body portion. Moreover, for example, the end of the body portion can be detected without a delay by using the second SYNC pattern. And by performing this, it is possible to continue or stop the tracking servo pull-in operation or the track jump operation, which are the important operations, in the condition that everything is ready, in the body portion. Incidentally, preferably, throughout the plurality of specific areas, a plurality of first SYNC patterns are arranged in the same phase, and a plurality of second SYNC patterns are arranged in the same phase.
In addition, the “SYNC (Synchronization) pattern” means a pattern that enables a unique signal waveform to appear at predetermined frequency in the recording or in the reproduction. Each of first and second SYNC signals, which are signals detected in the specific areas, has a unique signal waveform, and the detection thereof thus can be performed, simply and certainly.
<5>
Moreover, in this case, the first SYNC pattern is defined to detect a presence of the body portion in response to detection of the first SYNC pattern, and the second SYNC pattern is defined to detect an end of the body portion in response to detection of the second SYNC pattern.
By virtue of such a configuration, by the detection of the first SYNC pattern which enables the unique signal waveform to appear, it is possible to specify the next arrival of the body portion, i.e. timing to start the detection of the signal generated in crossing the tracks in the body portion (in other words, timing to perform the tracking servo pull-in operation and the track jump operation) or the arrival of the timing. This makes it possible to start the tracking servo pull-in operation and the track jump operation, as occasion demands. Then, after the detection of the signal generated in crossing the tracks in the body portion (in other words, the tracking servo pull-in operation and the track jump operation) is performed continuously to some extent, the end of the body portion is detected by the detection of the second SYNC pattern which enables the unique signal waveform to appear. This makes it possible to stop the tracking servo pull-in operation and the track jump operation, as occasion demands. In this case, there is no problem if the tracking servo pull-in operation and the track jump are completed before the second SYNC signal is detected; however, even if not completed, the end of the specific area can be recognized by detecting the second SYNC signal. Thus, the current operation using the specific area is forcibly terminated, and another option can be performed without a delay, including performing the operation again in the next cycle.
Incidentally, the body portion and the first and second SYNC patterns may be configured such that a specific signal is generated in crossing the tracks, not only in the body portion but also in the predetermined pattern including at least one of the first and second SYNC patterns.
<6>
In another aspect of the information recording medium of the present embodiment, the information recording medium adopts a zone CAV method, and the tracks are concentric or spiral.
According to this aspect, since the zone CAV method is adopted, the track jump is frequently performed, specifically if the concentric tracks are adopted. Alternatively, the track jump is performed, as occasion demands, even if the spiral track is adopted. In the guide layer, however, there are arranged the specific areas having the predetermined pattern described above, and thus, the use of the specific areas enables the start, continuation, and stop of the tracking servo pull-in to be performed without any problem, and enables the track jump operation to be performed without any problem.
<7>
In another aspect of the information recording medium of the present embodiment, each of the plurality of specific areas is disposed at a position corresponding to immediately before a portion in which arrangement of ECCs of data to be recorded into each of said recording layers is aligned in the radial direction.
According to this aspect, the specific area is disposed at the position in the guide layer corresponding to immediately before the portion in which the arrangement of error correction codes (ECCs) of the data to be recorded into the recording layer is aligned in the radial direction, i.e. immediately before the portion regarding the track direction. Thus, in either case of performing the recording from the inner circumference to the outer circumference or from the outer circumference to the inner circumference, a position or timing to perform the track jump can be easily obtained. In the same manner, it is also possible to easily obtain changing timing or a changing position of the tracking servo pull-in operation whose target is the lands or the grooves. Incidentally, the expression of “immediately before” includes both meanings of in front without another area between the specific area and the portion, and in front without an area other than the buffer area and the mirror-surface area between the specific area and the portion (i.e. in front only via the buffer area and the mirror-surface).
<8>
In another aspect of the information recording medium of the present embodiment, the guide information includes at least one of first recording address information directed from an inner circumference to an outer circumference in the track direction, and second recording address information directed from the outer circumference to the inner circumference.
According to this aspect, the first recording address information and the second recording address information are recorded in the guide layer which is a single layer. Alternatively, the first recording address information and the second recording address information are recorded in each of the guide layers which are two layers (or more layers). Then, it is possible to properly and selectively use the recording layers, as a first recording layer in which the recording is performed in accordance with the first address information, and a second recording layer in which the recording is performed in accordance with the second address information. Thus, it becomes efficient or easy to perform the operation of recording information from the inner circumference to the outer circumference in one or more first recording layers, and the operation of recording information from the outer circumference to the inner circumference in one or more second recording layers.
Moreover, the reliability or stability of the recording operation can be increased remarkably by properly using the two types of address information. Thus, it is possible to realize the information recording medium that allows the recording, continuously bidirectionally, or arbitrarily or independently bidirectionally.
In particular, if it is set to perform the recording or reproduction from the inner circumference to the outer circumference in the first layer of the recording layers and to perform the recording or reproduction from the outer circumference to the inner circumference in the second layer of the recording layers, that is extremely useful when the recording or reproduction is performed continuously over the plurality of recording layers, because a time to change the recording or reproduction between the two layers is almost a time to perform a layer jump.
At this time, if the first recording address information is recorded in advance in at least one of two types of slots arranged by a first rule, and if the first recording address information is recorded in advance in at least one of the two types of slots arranged by a second rule which is different from the first rule, it is possible to certainly and stably detect the address information which is necessary at that time point while reducing an influence of the crosstalk.
<9>
In another aspect of the information recording medium of the present embodiment, the tracks are guide tracks for tracking servo, the physical structure allows generation of a signal for the tracking servo which constitutes at least one portion of the guide information, each of the plurality of guide areas is a servo area for generating the signal for the tracking servo,
the predetermined distance is set in advance to a distance in which the tracking servo can operate in a predetermined band, and the plurality of servo areas are arranged such that the plurality of servo areas are shifted between the plurality of tracks so as not to be irradiated with a light beam simultaneously, on the basis of a diameter of the light beam for the tracking servo.
According to this aspect, the guide layer is a layer in which the tracks configured to generate the tracking error signal or the like are formed in order to track the position in the recording surface of each recording layer by using the first light beam, at least in the information recording into each recording layer.
More specifically, in the information recording, it is possible to detect the tracking error signal or the like from the reflected light obtained when the first light beam is focused on the tracks which exist in the guide layer. In accordance with the tracking error signal, the tracking or the tracking servo can be performed as one type of the guide operation.
Here, particularly in the embodiment, the plurality of servo areas are arranged separately from each other within the distance which is set in advance and in which the tracking servo can operate in the predetermined band, in the track direction. In other words, two servo areas in tandem in the track direction are arranged separately within the longest distance that allows the tracking signal to be generated continuously or continually from the servo areas at the frequency which enables the tracking operation to be performed stably in the predetermined band
Moreover, the plurality of servo areas are arranged such that the plurality of servo areas are shifted between the plurality of tracks so as not to be irradiated with the light beam simultaneously, on the basis of the diameter of the first light beam for the tracking servo.
Thus, even if the track density is increased until the spot of the first light beam straddles or covers two or more tracks or track portions which are adjacent to each other, as long as the servo areas are shifted as described above in response to the increased track density, it is possible to avoid a situation in which the tracking error signal cannot be detected due to the overlap of the tracking error signal (or the wobble signal as the basis thereof) in both the track direction and the radial direction (or due to an influence of a tracking error signal component from another servo area as the noise of the crosstalk). In other words, even if the track density is increased, the tracking can be performed, and the original function of generating the tracking signal as the guide layer is guaranteed.
Therefore, it is possible to stably and continuously generate the tracking error signal, for example, by sampling the push-pull signal obtained from the reflected light caused by the first light beam or the like, or by sampling a phase difference signal in differential phase detection (DPD), or by similar actions, while narrowing the track pitch. In other words, it is possible to perform the stable guide operation, such as the tracking operation.
Moreover, the tracking in the state in which the tracking servo is closed is performed stably by using the guide areas, while the tracking servo pull-in operation and the track jump operation in the state in which the tracking servo is open can be performed stably.
Incidentally, in the embodiment, mainly the guide areas may adopt various aspects as described below.
Preferably in the embodiment, a plurality of signal detection areas, each of which has an integrated predetermined pattern covering a plurality of track portions, are further arranged in the tracks such that a particular type of pattern signal can be detected in a center track portion, at least located near a central portion in the radial direction, out of the plurality of track portions which are adjacent to each other in the radial direction crossing the tracks.
According to this aspect, each of the plurality of signal detection areas has the integrated predetermined pattern covering the plurality of track portions, which are adjacent to each other in the radial direction, such that the particular type of pattern signal can be detected in the center track portion. The “center track portion” is a track portion, at least located near the central portion in the radial direction, such as in the central portion, at the center, or on a center line in the radial direction, out of the plurality of track portions which are adjacent to each other in the radial direction in each of the signal detection areas. For example, if the plurality of track portions are odd-numbered, such as three, five, and seven, the track portion in the middle is preferably set as the center track portion.
On the other hand, the track portions other than the center track portion dare to be excluded from a pattern signal detection target, even when the center of a first light spot by the first light beam is thereon. In other words, even if some signal or noise caused by the predetermined pattern can be detected in the track portions other than the center track portion, such a signal or noise is not detected as noise, or is discarded as noise after being detected.
The plurality of signal detection areas are arranged, typically discretely in the track direction, and also discretely in the radial direction. Thus, even if the track density is increased until the spot of the light beam straddles or covers two or more tracks or track portions which are adjacent to each other (e.g. until the spot covers five tracks, seven tracks, and the like), it is possible to avoid a situation in which the pattern signal cannot be detected due to the crosstalk of the patter signal detected.
For example, if the predetermined pattern is formed typically in advance or the predetermined pattern is recorded at an arbitrary time point after starting to use it such that a tilt detection signal, such as a tilt error signal, can be generated as the pattern signal, there is a significant signal change in the pattern signal when a tilt occurs, which is extremely useful in practice.
Specifically, for example, in the case of a tilt in the radial direction, if the predetermined pattern, which is axially symmetrical to the center track as a center line, is formed to be planarly spread in a direction covering the plurality of tracks, it is possible to generate the tilt detection signal which is excellent in sensitivity, for the tilt in the radial direction. Alternatively, in the case of a tilt in the track direction (i.e. a tangential direction), if the predetermined pattern, which is axially symmetrical to a line segment perpendicular to the tracks as the center line, is formed to be planarly spread in the direction covering the plurality of tracks, it is possible to generate the tilt detection signal which is excellent in sensitivity, for the tilt in the track direction. Alternatively, in the case of a tilt in a diagonal direction, if the predetermined pattern, which is axially symmetrical to a line segment diagonally crossing the tracks as the center line, is formed to be planarly spread in the direction covering the plurality of tracks, it is possible to generate the tilt detection signal which is excellent in sensitivity, for the tilt in the diagonal direction.
The predetermined pattern may be configured such that various signals are detected as the pattern signal, such as an eccentricity signal for eccentricity correction of a disc, an inclination signal for inclination correction of a disc surface, an aberration signal for aberration correction of an optical system, a phase difference signal for phase difference correction of a light beam, a distortion signal for distortion correction, a light absorption signal for light absorption correction, and a strategy signal for setting of a strategy, in addition to the tilt detection signal for the tilt correction.
The predetermined pattern is configured by forming a plurality of pits or a plurality of small optically-specific portions in each portion of the plurality of tracks in a planar area having annual circular shape (i.e. a hollow type) or a solid shape (i.e. a filled type) in which an outer ring shape thereof is circular, rectangular, or the like, in a form of covering the plurality of tracks. In other words, the predetermined pattern is composed of a series or group of the plurality of pits, the plurality of small optically-specific portions, and the like.
Here, as a result of the studies by the present inventors, it has been found that a special purpose of enabling a particular type of processing based on the pattern signal, such as, for example, the tilt correction based on the tilt detection signal, can be achieved even without continuously forming the pattern signal, such as the tilt detection signal, on all the tracks, even though it is necessary to allow the detection of the pattern signal, such as the tilt detection signal, in any track. It is rather rare that the particular type of processing is performed, identically and continuously. In other words, it has been found that the above specific purpose can be achieved if the pattern signal, such as the tilt detection signal, is detected in accordance with frequency or a period in which the particular type of processing is performed, for example, if the tilt detection signal is detected once every time the tilt correction is maintained at a constant value (in other words, every period in which the tilt servo is locked).
Thus, on one hand, regarding the plurality of tracks which are adjacent to each other, if the pattern signal is detected every plurality of tracks, it is possible to perform predetermined processing based on the pattern signal, practically completely, almost completely, or properly. On the other hand, regarding an area along the tracks, if the pattern signal is detected at some intervals or at intervals of any phase (e.g. angles on a disc), it is possible to perform the predetermined processing based on the pattern signal, practically completely, almost completely, or properly. After all, practically, it is enough to obtain the pattern signal intermittently on every plurality of tracks, such as, for example, five tracks and seven tracks, in the center track portion which represents the tracks. Moreover, phase positions (e.g. angular positions on the disc) in which the pattern signals are detected may be or may not be aligned or arranged in order.
Thus, in the embodiment, with respect to the signal detection area, an opportunity in which the center of the light spot of the first light beam is on the center track portion is used as a detection opportunity for the pattern signal. The track portions other than the center track portion dare to be excluded from the opportunity to detect the pattern signal even if the center of the light spot by the first light beam is thereon.
This works extremely useful, particularly in cases where the first light beam (e.g. red laser) has a larger beam diameter than that of the second light beam (e.g. blue laser) and in cases where the recording density in the information recording into one recording layer is increased nearly to the limit by effectively using the light spot of the second light beam which is relatively small (i.e. in accordance with the small size). In other words, if the narrow-pitch tracks, corresponding to the narrow-pitch recording area which will become the tracks after the recording in the recording layer, are formed in advance in the guide layer, the light spot of the first light beam, which is naturally larger than such tracks, has a technical characteristic of being simultaneously irradiated throughout the plurality of tracks (e.g. many tracks such as five tracks and seven tracks).
Thus, it is extremely advantageous to detect the integrated predetermined pattern covering the plurality of track portions which are adjacent to each other in the radial direction, by using the first light beam which forms the relatively large light spot. It can be also said that the light spot larger than the track pitch, which easily causes demerits, is effectively used.
Incidentally, even in cases where the first light beam has a smaller beam diameter than that of the second light beam, or even in cases where their diameters are almost or completely the same, as long as the predetermined pattern is detected when the diameter of the light beam is larger than the track pitch, the unique configuration of the embodiment as described above provides a proper operational effect.
As described above, the plurality of signal detection areas, each of which has the predetermined pattern, are arranged in the tracks. Thus, degree of freedom of the arrangement of the particular type of pattern signal, such as the tilt detection signal, remarkably increases. Moreover, the plurality of signal detection areas can be arranged, independently of each other, i.e. discretely. Thus, the arrangement with the degree of freedom is also possible on the entire information recording medium. By providing a plurality of types of pattern signals in association with a particular plurality of types of processing, it is also possible to perform the plurality of types of processing, as occasion demands.
Preferably in the embodiment, the plurality of guide areas are disposed in partial slots which are not adjacent to each other in the track direction and which are not adjacent to each other throughout the plurality of tracks in the radial direction, out of a plurality of slots. Typically, the plurality of guide areas are disposed in the partial slots, one by one.
Here, the “slot” is a logical section or division or a physical section or division obtained by dividing the track in the track direction. The slots are typically arranged continuously without gaps in the track direction and arranged without gaps in the radial direction or adjacently to each other. The slots, however, may be arranged with slight gaps in at least one of the track direction and the radial direction. In other words, the tracks are established from the arrangement or alignment of the plurality of slots formed to be arranged in the track direction in advance in the guide layer.
Since the guide areas are disposed in the plurality of slots which are not adjacent to each other in the track direction and which are not adjacent to each other throughout the plurality of tracks in the radial direction, it is possible to certainly reduce or eliminate the crosstalk between the guide information which can be detected from the plurality of guide areas. In addition, in the guide layer, it is sufficient to form the grooves, the lands, the pre-pits or the like, in the slots in which the guide areas are disposed, and it is unnecessary to form them continuously in the whole tracks. Moreover, the presence or absence of the slot (e.g. a difference between the slot and the mirror surface) can be distinguished physically and clearly and thus easily detected. This makes it easily possible to stably read the guide information. This is extremely useful in practice.
On the other hand, regarding the plurality of slots in each recording layer, as opposed to the case of the guide layer, individual recording areas for recording content data, user data, and the like may be disposed in all the slots that are continuous in both the track direction and the radial direction. Even any slots in the recording layer can correspond to the slots in which the guide areas are disposed in the guide layer, and thus, the tracking servo in the predetermined band can be performed indirectly to the recording layer. In other words, in the recording layer, the light spot formed by the second light beam allows information to be recorded into all the slots, at high density to the readable limit.
In addition, the plurality of specific areas are disposed in partial slots which are not adjacent to each other in the track direction and which are adjacent to each other throughout the plurality of tracks in the radial direction, out of the plurality of slots. In other words the plurality of specific areas are disposed inside a slot group arranged in the radial direction. Typically, the plurality of specific areas are disposed one by one in the partial slots which make such a slot group.
<10>
In order to solve the above object, a first information recording apparatus of the present embodiment is an information recording apparatus for recording data onto an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information recording apparatus is provided with: a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data recording on one recording layer out of the plurality of recording layers; an information obtaining device for receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a first pull-in controlling device for controlling start or continuation of a pull-in operation of pulling in the tracking servo on the basis of one type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open; a second pull-in controlling device for controlling continuation or end of the pull-in operation on the basis of another type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open or is being pulled in; a tracking servo device for controlling the light irradiating device to perform the tracking servo on a desired track out of the plurality of tracks on the basis of the obtained guide information; and a data recording control device for controlling the light irradiating device to record the data by irradiating and focusing the second light beam on the one recording layer in a servo-closed state in which the tracking servo is performed.
According to the first information recording apparatus in the embodiment, the first light beam is irradiated and focused on the guide layer by the light irradiating device, which is, for example, an optical pickup including two types of semiconductor lasers. The first light beam may be a light beam with a relatively large spot diameter as in the red laser light beam, as described above. In other words, the first light beam may be a light beam with a large light flux which forms a large light spot irradiated throughout the plurality of tracks.
Then, the first light, such as reflected light, scattered light, refracted light, and transmitted light from the guide layer, based on the first light beam is received by a light receiving device. Here, the light receiving device includes, for example, a photodetector or a light receiving element such as a two-division or four-division charged coupled device (CCD), which is formed integrally with the light irradiating device and which shares an optical system such as an objective lens, at least partially. The light receiving device is configured to receive the first light in an optical path which is different from the optical paths for second light and the first and second light beams from the middle, via a prism, a dichroic mirror, a dichroic prism, and the like.
Here, in particular, if the tracking servo is open in an initial state, in the middle of, or before or after searching for a target position, the predetermined pattern owned by the specific areas is detected by the information obtaining device including, for example, a processor, an arithmetic circuit, a logical circuit, etc., on the basis of the first light received by the light receiving device.
Before or after, or in parallel with the detection, the start of the tracking servo pull-in operation is controlled by the first pull-in controlling device on the basis of the one type of the predetermined pattern detected by the information obtaining device (e.g. the first SYNC pattern detected in the state in which the tracking servo is open).
Specifically, the light irradiating device, such as an optical pickup, is displaced in the radial direction as a direction of crossing the tracks, for example, in response to the confirmation of a waveform of the one type of the predetermined pattern, by the tracking servo device, such as, for example, a tracking servo circuit, under the control of the first pull-in controlling device. For example, a tracking control actuator of the light irradiating device is controlled by feedback control or feed-forward control, and the light beam formed by the first light beam is displaced to cross the tracks.
Then, the light irradiating device is displaced in the radial direction to the side closer to a target track (i.e. a track in the guide layer corresponding to a radial position at which the recording is to be performed in the recording layer and which will make a recorded information track after the recording), on the basis of the predetermined pattern detected by the information obtaining device (e.g. the body portion having the combination of the grooves and the lands) in the state in which the tracking servo is open or is being pulled in, as described above. Moreover, the stop of the tracking servo pull-in operation is controlled by the second pull-in controlling device on the basis of the another type of the predetermined pattern detected by the information obtaining device (e.g. the second SYNC pattern detected in the state in which the tracking servo is open).
Specifically, the light irradiating device, such as an optical pickup, is stopped in the radial direction as the direction of crossing the tracks, for example, in response to the confirmation of a waveform of the another type of the predetermined pattern, by the tracking servo device, such as, for example, a tracking servo circuit, under the control of the second pull-in controlling device. For example, the tracking control actuator of the light irradiating device is controlled by feedback control or feed-forward control, and the light beam formed by the first light beam is stopped at a radial position in the vicinity of the target track. In this case, even if the tracking servo pull-in operation cannot be completed, the end of the specific area can be recognized by detecting the second SYNC signal. Thus, the current operation using the specific area is forcibly terminated, and another option can be performed without a delay, including performing the operation again in the next cycle.
Incidentally, the first and second pull-in controlling devices may be established as a single circuit.
As a result of the pull-in operation performed by the first and second pull-in controlling devices, the tracking servo pull-in is performed on the target track.
Then, the guide information carried by the physical structure of each of the guide areas is obtained by the information obtaining device including, for example, a processor, an arithmetic circuit, a logical circuit, etc., on the basis of the first light received by the light receiving device.
Then, the light irradiating device such as, for example, an optical pickup, is controlled by the tracking servo device, such as a tracking servo circuit, to perform the tracking servo in the predetermined band on the tracks or to close the tracking servo, on the basis of the obtained guide information. For example, an actuator for tracking control of the light irradiating device is controlled under feedback-control or feed-forward control, and the light beam formed by the first light beam tracks or follows on the tracks. Particularly at this time, in order to perform the tracking servo in the predetermined band, there is no need to provide the guide areas which allow the guide information to be generated in all the slots along the tracks. In other words, it is enough to arrange the slots including the guide areas, separately in both the track direction and the radial direction, in accordance with the predetermined band.
The second light beam, which is modulated in accordance with the information to be recorded, is irradiated and focused by the light irradiating device under the control by the data recording control device, such as, for example, a processor, in a state in which the tracking servo is performed in the predetermined band or the tracking servo is closed, as described above. The second light beam may be a light beam with a relatively small spot diameter, for example, as in the blue laser light beam as described above, aimed at the high density recording of the information recording. From the viewpoint of realizing high-density record information, the second light beam is desirably a smaller light flux.
Then, in the desired recording layer, the data is sequentially recorded into an area which will make the information tracks corresponding to the tracks in the guide layer. At this time, if the recording of the data into the recording layer is performed by a unit corresponding to the slot, such as an integral multiple of the slot, then, the recording operation becomes simple and stable.
As described above, it is possible to preferably record the information to be recorded, such as, for example, content information and user information, at high density into the recording layer of the information recording medium in the embodiment described above, while performing the tracking servo pull-in on the target track, as occasion demands.
<11>
In order to solve the above object, a second information recording apparatus of the present embodiment is an information recording apparatus for recording data onto an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information recording apparatus is provided with: a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data recording on one recording layer out of the plurality of recording layers; an information obtaining device for receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a jump controlling device for controlling a track jump associated with the tracks on the basis of one type of the detected predetermined pattern in the plurality of specific areas in a servo-closed state in which the tracking servo is performed; and a data recording control device for controlling the light irradiating device to record the data by searching for a desired position on the plurality of tracks on the basis of the obtained guide information when the track jump is performed and by irradiating and focusing the second light beam on the one recording layer in the servo-closed state.
According to the second information recording apparatus in the embodiment, as in the first information recording apparatus described above, the first light beam is irradiated and focused by the light irradiating device, and the first light is received by the light receiving device.
Here, in particular, if the tracking servo is closed in the initial state, in the middle of, or before or after searching for the target position, the predetermined pattern owned by the specific areas is detected by the information obtaining device including, for example, a processor, an arithmetic circuit, a logical circuit, etc., on the basis of the first light received by the light receiving device.
Before or after, or in parallel with the detection, the track jump is controlled by the jump controlling device on the basis of the one type of the predetermined pattern detected by the information obtaining device (e.g. the first SYNC pattern detected in the state in which the tracking servo is not only servo-closed but also open, and the body portion having the combination of the grooves and the lands). At this time, the tracking servo is preferably held.
Specifically, the light irradiating device, such as an optical pickup, is displaced in the radial direction as the direction of crossing the tracks, for example, in response to the confirmation of the waveform of the one type of the predetermined pattern, by the tracking servo device, such as, for example, a tracking servo circuit, under the control of the jump controlling device. For example, the tracking control actuator of the light irradiating device is controlled by feedback control or feed-forward control, and the light beam formed by the first light beam is displaced to cross the tracks. Before or after, or in parallel with the displacement, the number of the tracks crossed is counted from a signal waveform corresponding to the detected predetermined pattern, by which the displacement to the target track is controlled by the jump controlling device.
As a result, the light receiving device performs the track jump in the radial direction so as to approach the target track, and eventually, the stop of the track jump is controlled by the jump controlling device. Specifically, the light irradiating device, such as an optical pickup, is stopped at a radial position in the vicinity of the target track in accordance with (i) the number of the tracks crossed, (ii) a track number of the target track, and (iii) a relation with a track number of the track from which the track jump is started, by the tracking servo device, such as a tracking servo circuit, under the control of the jump controlling device.
As a result of the jump operation performed by the jump controlling device as described above, the tracking servo pull-in can be performed on the target track.
Then, if the track jump is performed as described above, before or after, or in parallel with the track jump operation, the desired position on the plurality of tracks is searched for on the basis of the guide information obtained based on the first light, by the searching device including, for example, a processor, an arithmetic circuit, a logical circuit, etc. provided for the data recording control device. In other words, the target track is searched for. Moreover, in this case, at the searched desired position, as in the first information recording apparatus described above, the guide information is obtained by the information obtaining device, and the light irradiating device is controlled, for example, such that the tracking servo is performed or that the tracking servo is closed by the tracking servo device. Moreover, under the control of the data recording control device, the second light beam is irradiated and focused by the light irradiating device, and the data is sequentially recorded.
Alternatively, if the track jump is not performed, as in the first information recording apparatus described above, the guide information is obtained by the information obtaining device, and the light irradiating device is controlled, for example, such that the tracking servo is performed or the tracking servo is closed by the tracking servo device. Moreover, under the control of the data recording control device, the second light beam is irradiated and focused by the light irradiating device, and the data is sequentially recorded. Incidentally, the expression of “if the track jump is not performed” means a case where the track jump is not performed in the state in which the tracking servo is closed, and includes the current case where the track jump is performed before the tracking servo is closed.
As described above, it is possible to preferably record the information to be recorded, such as, for example, content information and user information, at high density into the recording layer of the information recording medium in the embodiment described above, while performing the track jump on the target track, as occasion demands.
<12>
In order to solve the above object, a first information recording method of the present embodiment is an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information recording method recording the data by using a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data recording on one recording layer out of the plurality of recording layers, the information recording method is provided with: an information obtaining process of receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a first pull-in controlling process of controlling start or continuation of a pull-in operation of pulling in the tracking servo on the basis of one type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open; a second pull-in controlling process of controlling continuation or end of the pull-in operation on the basis of another type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open or is being pulled in; a tracking servo process of controlling the light irradiating device to perform the tracking servo on a desired track out of the plurality of tracks on the basis of the obtained guide information; and a data recording control process of controlling the light irradiating device to record the data by irradiating and focusing the second light beam on the one recording layer in a servo-closed state in which the tracking servo is performed.
According to the first information recording method in the embodiment, it acts in the same manner as in the first information recording apparatus in the embodiment described above, and eventually, it is possible to preferably record the information to be recorded, such as the content information and the user information, at high density into the recording layer of the information recording medium in the embodiment described above, while performing the tracking servo pull-in, as occasion demands.
<13>
In order to solve the above object, a second information recording method of the present embodiment is an information recording method of recording data onto an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information recording method recording the data by using a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data recording on one recording layer out of the plurality of recording layers, the information recording method is provided with: an information obtaining process of receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a jump controlling process of controlling a track jump associated with the tracks on the basis of one type of the detected predetermined pattern in the plurality of specific areas in a servo-closed state in which the tracking servo is performed; and a data recording control process of controlling the light irradiating device to record the data by searching for a desired position on the plurality of tracks on the basis of the obtained guide information when the track jump is performed and by irradiating and focusing the second light beam on the one recording layer in the servo-closed state.
According to the second information recording method in the embodiment, it acts in the same manner as in the second information recording apparatus in the embodiment described above, and eventually, it is possible to preferably record the information to be recorded, such as the content information and the user information, at high density into the recording layer of the information recording medium in the embodiment described above, while performing the track jump, as occasion demands.
<14>
In order to solve the above object, a first information reproducing apparatus of the present embodiment is an information reproducing apparatus for reproducing data from an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information reproducing apparatus is provided with: a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data reproduction on one recording layer out of the plurality of recording layers; an information obtaining device for receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a first pull-in controlling device for controlling start or continuation of a pull-in operation of pulling in the tracking servo on the basis of one type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open; a second pull-in controlling device for controlling continuation or end of the pull-in operation on the basis of another type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open or is being pulled in; a tracking servo device for controlling the light irradiating device to perform the tracking servo on a desired track out of the plurality of tracks on the basis of the obtained guide information; and a data obtaining device for receiving second light based on the irradiated and focused second light beam from the one recording layer and obtaining the data on the basis of the received second light in a servo-closed state in which the tracking servo is performed.
According to the first information reproducing apparatus in the embodiment, the first light beam is irradiated and focused on the guide layer by the light irradiating device.
Then, the first light based on the first light beam is received by the light receiving device.
Here, in particular, if the tracking servo is open, the predetermined pattern owned by the specific areas is detected by the information obtaining device on the basis of the first light received by the light receiving device.
Before or after, or in parallel with the detection, the start of the tracking servo pull-in operation is controlled by the first pull-in controlling device on the basis of the one type of the predetermined pattern detected by the information obtaining device.
Then, the light irradiating device is displaced in the radial direction to the side closer to the target track, on the basis of the predetermined pattern detected by the information obtaining device, in the state in which the tracking servo is open or is being pulled in. Moreover, the stop of the tracking servo pull-in operation is controlled by the second pull-in controlling device, on the basis of the another type of the predetermined pattern detected by the information obtaining device.
As a result of the pull-in operation performed by the first and second pull-in controlling devices, the tracking servo pull-in is performed on the target track.
Then, the guide information carried by the physical structure of each of the guide areas is obtained by the information obtaining device on the basis of the first light received by the light receiving device.
Then, the light irradiating device is controlled by the tracking servo device to perform the tracking servo in the predetermined band on the tracks or to close the tracking servo, on the basis of the obtained guide information.
The second light beam is irradiated and focused on the desired recording layer by the light irradiating device under the control by the data obtaining device, such as, for example, a processor, in a state in which the tracking servo is performed in the predetermined band or the tracking servo is closed as described above.
Then, in the desired recording layer, the recorded data is reproduced.
As described above, it is possible to reproduce the recorded information, such as, for example, the content information and the user information, at high density preferably from the recording layer of the information recording medium in the embodiment described above, while performing the tracking servo pull-in, as occasion demands.
Incidentally, it is also possible to reproduce the information from the information tracks while performing the tracking on the information tracks which are established as the arrangement or alignment of the recorded information, by using only the second light beam, without using the tracking by the guide layer, i.e. without using the first light beam. In other words, it is also possible to establish the information reproducing apparatus so as to properly use the light beam in accordance with a distinction between the recording and the reproduction, such as using only the second light beam in the information reproduction and using both the first and second light beams in the information recording. In the information reproduction, only the second light beam is used, and the reproduction can be thus performed with relatively low power consumption and simple control (i.e. in comparison with the case of using the first light beam in the reproduction). In particular, it is extremely useful in practice if the information reproducing apparatus is realized as an “information recording/reproducing apparatus” having a recording function of properly using the light beam between the information recording and the information reproduction.
<15>
In order to solve the above object, a second information reproducing apparatus of the present embodiment is an information reproducing apparatus for reproducing data from an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information reproducing apparatus is provided with: a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data reproduction on one recording layer out of the plurality of recording layers; an information obtaining device for receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a jump controlling device for controlling a track jump associated with the tracks on the basis of one type of the detected predetermined pattern in the plurality of specific areas in a servo-closed state in which the tracking servo is performed; and a data obtaining device for searching for a desired position on the plurality of tracks on the basis of the obtained guide information when the track jump is performed, receiving second light based on the irradiated and focused second light beam from the one recording layer, and obtaining the data on the basis of the received second light in the servo-closed state.
According to the second information reproducing apparatus in the embodiment, as in the first information reproducing apparatus described above, the first light beam is irradiated and focused by the light irradiating device, and the first light is received by the light receiving device.
Here, in particular, if the tracking servo is servo-closed, the predetermined pattern owned by the specific areas is detected by the information obtaining device on the basis of the first light received by the light receiving device.
Before or after, or in parallel with the detection, the track jump is controlled by the jump controlling device on the basis of the one type of the predetermined pattern detected by the information obtaining device.
As a result, the track jump is performed in the radial direction such that the light irradiating device approaches the target track, and eventually, the stop of the track jump is controlled by the jump controlling device. Moreover, in the state in which the tracking servo is performed in a predetermined band or in the state in which the tracking servo is closed, as described above, the second light beam is irradiated and focused on the desired recording layer by the light irradiating device, and the recorded information is reproduced from the desired recording layer.
As described above, it is possible to preferably reproduce the recorded information, such as the content information and the user information, at high density from the recording layer of the information recording medium in the embodiment described above, while performing the track jump, as occasion demands.
Incidentally, it is also possible to reproduce the information from the information tracks while performing the tracking on the information tracks which are established as the arrangement or alignment of the recorded information, by using only the second light beam, without using the tracking by the guide layer, i.e. without using the first light beam.
<16>
In order to solve the above object, a first information reproducing method of the present embodiment is an information reproducing method of reproducing data from an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information reproducing method reproducing the data by using a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data reproduction on one recording layer out of the plurality of recording layers, the information reproducing method is provided with: an information obtaining process of receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a first pull-in controlling process of controlling start or continuation of a pull-in operation of pulling in the tracking servo on the basis of one type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open; a second pull-in controlling process of controlling continuation or end of the pull-in operation on the basis of another type of the detected predetermined pattern in the plurality of specific areas in the state in which the tracking servo is open or is being pulled in; a tracking servo process of controlling the light irradiating device to perform the tracking servo on a desired track out of the plurality of tracks on the basis of the obtained guide information; and a data obtaining process of receiving second light based on the irradiated and focused second light beam from the one recording layer and obtaining the data on the basis of the received second light in a servo-closed state in which the tracking servo is performed.
According to the first information reproducing method in the embodiment, it acts in the same manner as in the first information reproducing apparatus in the embodiment described above, and eventually, it is possible to preferably reproduce the recorded information, such as the content information and the user information, at high density from the recording layer of the information recording medium in the embodiment described above, while performing the tracking servo pull-in, as occasion demands.
<17>
In order to solve the above object, a second information reproducing method of the present embodiment is an information reproducing method of reproducing data from an information recording medium, the information recording medium is provided with: a guide layer in which concentric or spiral tracks are formed in advance; and a plurality of recording layers laminated on the guide layer, wherein on the tracks, (i) a plurality of guide areas, each of which has a physical structure for carrying guide information for guidance, are arranged discretely at arrangement intervals of predetermined distance or less which is set in advance in a track direction along the tracks and are shifted between a plurality of tracks throughout the plurality of tracks which are adjacent to each other in a radial direction crossing the tracks, and (ii) a plurality of specific areas, each of which has a predetermined pattern, are respectively arranged in a same phase from an inner circumference to an outer circumference in the radial direction such that the predetermined pattern can be detected in a state in which tracking servo is open, the information reproducing method reproducing the data by using a light irradiating device capable of irradiating and focusing a first light beam for tracking on the guide layer and capable of irradiating and focusing a second light beam for data reproduction on one recording layer out of the plurality of recording layers, the information reproducing method is provided with: an information obtaining process of receiving first light based on the irradiated and focused first light beam from the guide layer, and detecting the predetermined pattern and obtaining the carried guide information on the basis of the received first light; a jump controlling process of controlling a track jump associated with the tracks on the basis of one type of the detected predetermined pattern in the plurality of specific areas in a servo-closed state in which the tracking servo is performed; and a data obtaining process of searching for a desired position on the plurality of tracks on the basis of the obtained guide information when the track jump is performed, receiving second light based on the irradiated and focused second light beam from the one recording layer, and obtaining the data on the basis of the received second light in the servo-closed state.
According to the second information reproducing method in the embodiment, it acts in the same manner as in the second information reproducing apparatus in the embodiment described above, and eventually, it is possible to preferably reproduce the recorded information, such as the content information and the user information, at high density from the recording layer of the information recording medium in the embodiment described above, while performing the track jump, as occasion demands.
The operation and other advantages in the embodiments will become more apparent from an example explained below.
As explained above, according to the information recording medium in the embodiment, it is provided with: the guide layer; and the plurality of recording layers, and the plurality of guide areas and the plurality of specific areas are disposed on the tracks. Thus, it is possible to improve the track pitch and the recording linear density which allow the recording or reproduction in the recording layer while performing the tracking servo pull-in and the track jump, as occasion demands.
According to the first information recording apparatus in the embodiment, it is provided with: the light irradiating device; the information obtaining device; the first and second pull-in controlling devices; the tracking servo device; and the data recording control device. According to the first information recording method in the embodiment, it is provided with: the information obtaining process; the first and second pull-in controlling processes; the tracking servo process; and the data recording control process. Thus, it is possible to preferably record the information to be recorded, such as the content information and the user information, at high density into the recording layer of the information recording medium in the embodiment described above, while performing the tracking servo pull-in, as occasion demands.
According to the second information recording apparatus in the embodiment, it is provided with: the light irradiating device; the information obtaining device; the jump controlling device; and the data recording control device. According to the second information recording method in the embodiment, it is provided with: the information obtaining process; the jump controlling process; and the data recording control process. Thus, it is possible to preferably record the information to be recorded, such as the content information and the user information, at high density into the recording layer of the information recording medium in the embodiment described above, while performing the track jump, as occasion demands.
According to the first information reproducing apparatus in the embodiment, it is provided with: the light irradiating device; the information obtaining device; the first and second pull-in controlling devices; the tracking servo device; and the data obtaining device. According to the first information reproducing method in the embodiment, it is provided with: the information obtaining process; the first and second pull-in controlling processes; the tracking servo process; and the data obtaining process. Thus, it is possible to preferably reproduce the recorded information at high density from the recording layer of the information recording medium in the embodiment described above, while performing the tracking servo pull-in, as occasion demands.
According to the second information reproducing apparatus in the embodiment, it is provided with: the light irradiating device; the information obtaining device; the jump controlling device; and the data obtaining device. According to the second information reproducing method in the embodiment, it is provided with: the information obtaining process; the jump controlling process; and the data obtaining process. Thus, it is possible to preferably reproduce the recorded information at high density from the recording layer of the information recording medium in the embodiment described above, while performing the track jump, as occasion demands.
Hereinafter with reference to the drawings, various examples of the present invention will be explained. Incidentally, hereinafter, an explanation will be given to an example in which the information recording medium of the present invention is applied to an optical disc of a multilayer recording type.
Firstly, with reference to
Firstly, with reference to
In
The optical disc 11 is irradiated simultaneously with a first beam LB1 for tracking servo as one example of the “first light beam” of the present invention and a second beam LB2 for information recording as one example of the “second light beam” of the present invention, in recording. In reproduction, the optical disc 11 is irradiated simultaneously with the first beam LB1 and the second beam LB2 for information reproduction. Incidentally, in the information reproduction, the second beam LB2 can be also used as a single light beam for the tracking servo and for the information reproduction (i.e. the first beam LB1 is not used).
The optical disc 11 adopts the zone CAV method, and a tracking error signal (or a wobble signal as a basis thereof), address information (or a pre-pit signal as a basis thereof), and the like, which are recorded in advance in concentric tracks or a spiral track TR and which are detected in the information recording or reproduction, are arranged along the tracks in accordance with the zone CAV method. In
As illustrated in
The plurality of recording layers 13 are configured such that information can be optically recorded or further reproduced independently in each of the recording layers 13, such as, for example, 16 layers. More specifically, each of the plurality of recording layers 13 is made of a semitransparent thin film including a two-photon absorption material. For example, as the two-photon absorption material, it is possible to adopt a fluorescent type using a fluorescent material in which fluorescent intensity changes in an area in which two-photon absorption occurs, a refractive-index change type using a photorefractive material in which a refractive index changes due to electron localization, and the like. As the two-photon absorption material of the refractive-index change type, the use of a photochromic compound, a bis(alkylidene)cycloalkanone, or the like is highly expected.
As an optical disc structure using the two-photon absorption material, there are (i) a bulk type in which the entire optical disc 11 is made of the two-photon absorption material and (ii) a layered structure type in which the recording layers 13 made of the two-photon absorption material and spacer layers made of another transparent material are alternately laminated. The layered structure type has the advantage that focus servo control can be performed by using light reflected on an interface between one recording layer 13 and the spacer layer. The bulk type has the advantage that it has less multilayer film formation processes and production costs can be kept low.
As the material of the recording layers 13, there may be listed a material which reacts to at least one of intensity and wavelength of the second beam LB2, which allows the recording by changing optical properties, such as a refractive index, transmittance, absorptivity, and reflectance, and which is stable. For example, a translucent or semitransparent photoresponse material, such as a photopolymer which allows a photopolymerization reaction, an optical anisotropic material, a photorefractive material, a hole burning material, and a photochromic material which absorbs light to change an absorption spectrum can be listed. For example, as the recording layers 13, a phase-change material, the two-photon absorption material, and the like are used, each of which reacts to the second beam LB2 with a wavelength of λ2 but does not react to the first beam LB1 with λ1 (λ2<λ1).
Each of the plurality of recording layers 13 may be made of, for example, a dye material, in addition to the two-photon absorption material and the phase-change material described above. In each of the plurality of recording layers 13, the track TR is not formed in advance in an unrecorded state, and for example, the entire area is a mirror surface or a smooth plane.
The optical disc 11 having the plurality of recording layers 13 laminated on the guide layer 12 is irradiated with the first beam LB1 and the second beam LB2 having different diameters and focal depths, in a condition that the first beam LB1 and the second beam LB2 are almost coaxial or practically completely coaxial, via a common objective lens 102L provided for an optical pickup, at least in the information recording.
In
On the tracks TR of the guide layer 12, a plurality of servo areas are arranged, each of which has a physical structure for carrying the tracking error signal (or a signal for generating a tracking error, such as the wobble signal as the basis thereof) and the pre-pit signal. Here, the tracking error signal and the pre-pit signal constitute one example of the “guide information for guidance” according to the present invention. The plurality of servo areas constitute one example of the “plurality of guide areas” according to the present invention.
Now, with reference to
As illustrated in
The groove tracks GT have wobbles WB on the side walls thereof. In other words, the groove tracks GT are formed such that the side walls thereof wobble in a track direction.
In
In
In contrast, in the specific example in
Incidentally, as illustrated in
Alternatively, as illustrated in
In addition, in
Now, with reference to
As illustrated in
As illustrated in
In particular, in the case of the zone CAV method as in the example, as opposed to the case of the CAV method, an address positional relation (an address difference) on the plurality of adjacent tracks TR changes depending on the radial position. Thus, even if the tracking is possible in one place, there is a significant possibility that the tracking is impossible in another place (i.e. in a position in which the degree of an approach of other signal generation areas is high, where the signal generation areas are adjacent in the radial direction).
The same is true in cases where the land pre-pits LPP1 adjacently exist, as illustrated in
The situation as illustrated in
However, the special purpose of performing the tracking in a predetermined frequency band can be achieved without forming the wobble structure for detecting the tracking error signal and the pre-pit structure (refer to
In addition, for the special purpose of detecting not only the tracking error signal but also another control information for recording control or reproduction control, such as the address information by using the pre-pits such as the land pre-pits LPP1, it is not necessary to form the wobble structure, the pre-pit structure and the like (refer to
Thus, in the example, in particular, in order to achieve the special purpose of enabling mainly the tracking, the plurality of servo areas are provided on the tracks TR, discretely, in both the track direction and the radial direction, as explained below.
Next, with reference to
As illustrated in
Here, the mirror-surface area 21 may have a straight groove or a straight land formed. In this case, the mirror-surface area 21 can be referred to as a “groove area”. Alternatively, since the mirror-surface area 21 has a buffering function in reading the other servo area 22 and the other pattern area 23, the mirror-surface area 21 can be referred to as a “buffer area”. In this case, the mirror-surface area 21 is one example of the “buffer area” of the present invention.
In
By the buffer function of the mirror-surface area 21, a preparation period for the detection of a signal from the servo area 22 is given in a servo system in the information recording or the like. In particular, the first beam LB1 can be moved into the servo area 22 in a tracking-on state in the information recording. In other words, the mirror-surface area 21 disposed on the head side of the servo area 22 gives an extremely effective preparation period to stably operate the tracking servo.
The servo area 22 is an area in which the wobble structure and the pre-pit structure are formed in advance, as illustrated in
The mark information is disposed immediately before the pattern area 23 on a center track 23TR and indicates that the pattern area 23 is located immediately thereafter. Thus, in the recording or reproduction, if the mark information is firstly detected in the servo area 22, it is found that a pattern signal of the pattern area 23 will arrive later without a delay. Alternatively, the mark information indicates timing to sample the pattern area 23 located thereafter, or an address position of the pattern area 23 located thereafter directed from the inner circumference to the outer circumference, or from the outer circumference to the inner circumference, in the track direction, on the center track 23TR. Thus, in the recording or reproduction, if the mark information is firstly detected in the servo area 22, it is found in which timing or at which address position the pattern signal will arrive.
If the first light beam is not on the integrated one center track composed of a plurality of tracks, the wobble signal detected by using a push-pull signal is detected with offset in the pattern area 23. Thus, it can be recognized whether or not the first light beam is on the center track 23TR.
The pattern area 23, which is one example of the “signal detection area” of the present invention, has an integrated predetermined patterns 23a which covers seven tracks adjacent to each other in the radial direction (in the vertical direction in
On the other hand, the track portion other than the center track 23TR dares to be excluded from a pattern signal detection target even when the center of a first light spot LS1 by the first light beam is directly on the track portion.
The pattern areas 23 are discretely arranged in the track direction (in the horizontal direction in
As the pattern signal, the predetermined pattern 23a is prepared in advance such that the tilt detection signal, such as a tilt error signal, can be generated. Thus, a significant signal change in the tilt detection signal can be obtained when the tilt occurs.
The predetermined pattern 23a is formed of shortly notched grooves or lands which are locally concavo-convex, or short pits or embosses formed in groove tracks or land tracks, or a plurality of pieces of embossed pits. For example, if covering the seven tracks, the predetermined pattern 23a is provided with a set of five embossed pits on either side, i.e. a set of 10 embossed pits on both sides in total, or the like. The predetermined pattern 23a is formed to substantially fit an outer rim shape of the light spot LS1 and has a shape which is substantially along a bright ring LS1a if the bright ring LS1a is generated. The predetermined pattern 23a may be combined with the wobbles.
Incidentally, the predetermined pattern 23a in the pattern area 23 may be configured such that various signals are detected as the pattern signal, such as an eccentricity signal for eccentricity correction of a disc, an inclination signal for inclination correction of a disc surface, an aberration signal for aberration correction of an optical system, a phase difference signal for phase difference correction of a light beam, a distortion signal for distortion correction, a light absorption signal for light absorption correction, and a strategy signal for setting of a strategy, in addition to the tilt detection signal.
Here, a particular purpose of enabling tilt correction based on the tilt detection signal can be achieved without forming the tilt detection signal continuously on all the tracks TR, even though there is a need to make it possible to detect the tilt detection signal on any of the tracks TR. In other words, the particular purpose can be achieved if the tilt detection signal is detected in accordance with frequency or a period to perform the tilt correction, such as the tilt detection signal being detected once in each period in which tilt servo is locked.
Thus, on one hand, if the tilt detection signal can be obtained on every seven tracks in one GR, the tilt correction can be performed. On the other hand, in the case of an area along the track TR, if the tilt detection signal can be obtained at some intervals or at any phase (e.g. angles on a disc), the tilt correction can be performed. After all, it is enough to obtain the tilt detection signal intermittently on every seven tracks in one GR on the center track 23TR which represents the seven tracks.
In the example, the fact that the first beam LB1 (e.g. red laser) has a larger beam diameter than that of the second beam LB2 (e.g. blue laser) is extremely advantageous to detect the group of predetermined patterns 23a which covers the seven tracks TR which constitute one group GR, by using the first beam LB1.
In the pattern area 23 having the tilt detection pattern as described above, arrangement with degree of freedom is possible. In addition, by providing a pattern signal other than the tilt detection signal in response to processing other than the tilt correction, it is also possible to perform other processing in parallel with the tilt correction or as occasion demands.
Moreover, in the example, in particular, the servo area 22 carrying the mark information, which indicates that the pattern area 23 is located thereafter, is disposed in front of the pattern area 23 on the center track 23TR in the track direction. The mark information is information reproduced by using the wobble signal and the pre-pit signal or the like corresponding to the wobbles and the pre-pits or the like which are discretely formed in the servo area 22.
Thus, the tilt detection signal can be read, easily and certainly, on the basis of the arrival of the mark information. For example, it is possible to start preparation for starting to detect the tilt detection signal after the detection of the mark information, or further preparation for starting the tilt correction based on the tilt detection signal. For example, by defining in advance a phase relation and an interval between the tilt detection signal and the mark information, it is possible to easily specify sampling timing to detect the tilt detection signal from the mark information. Alternatively, by providing the mark information with the address position at which the tilt detection signal is recorded, it is possible to easily specify the sampling timing to detect the tilt detection signal.
The specific area 24 is disposed in the same phase from the inner circumference to the outer circumference in the radial direction such that a predetermined pattern of the specific area 24 can be detected in the state in which the tracking servo is open, in the recording or reproduction of the optical disc 11.
As illustrated in
Each of the first and second SYNC patterns has at least one of the wobble and pre-pit structure, and the wobble and partial-notch structure (refer to
As detailed later, the pattern in the specific area 24 can be detected in the state in which the tracking servo is open in the recording or reproduction; however, the pattern can be also detected even in a state in which the tracking servo is servo-closed. The detection of the pattern in the open state enables a tracking servo pull-in operation to be preferably performed. The detection of the pattern in the servo-closed state enables a track jump operation to be more preferably performed.
As illustrated in
As illustrated in
As illustrated in
In
In the pattern area 23, the tilt detection pattern is formed by a slot unit as the pattern signal in the slot 300B. In the pattern area 23, one pattern is established in a form of covering the seven tracks, as the tilt detection pattern. As illustrated as the pattern area 23 in a rectangle at the lower right of the drawing, in this example, a pattern which fits an upper half on the outer rim of the light spot LS1 (i.e. the bright ring LS1a) is formed immediately after the servo area 22, and subsequently, at a slight distance therefrom, a pattern which fits a lower half on the outer ring of the light spot LS1 (i.e. the bright ring LS1a) is formed. One tilt detection pattern is established from the two patterns.
In the specific area 24, a physical structure for forming the predetermined pattern detailed later (refer to
In
Hereinafter, this point will be explained in detail with reference to
In
In
Thus, in the example, not the pattern as illustrated on the left side of the drawing but the pattern as illustrated in the right half of the drawing are adopted as the body portion of the predetermined pattern in the specific area 24. Incidentally,
Next, in
In the specific example illustrated in
In the specific example illustrated in
In the specific example illustrated in
In the specific example illustrated in
In the example, as illustrated in
More specifically, the specific pattern 24 is formed in areas whose start positions on the optical disc 11 are substantially aligned in the radial direction and whose end positions are substantially aligned in the radial direction at least in a certain range of area, such as, for example, each zone in the zone CAV (refer to
Moreover, the second SYNC pattern having a different length along the track from that of the first SYNC pattern is formed in the second SYNC pattern area 24-3 (i.e. on the end portion side of the specific area 24) in the physical shape in the same manner as the first SYNC pattern.
In the body area 24-2 located between the first and second SYNC areas 24-1 and 24-3, the body portion of the predetermined pattern, in which the grooves or the lands are alternately arranged on all the tracks or every other or two tracks or the like, is formed along the tracks 24G to cover the plurality of tracks which are adjacent to each other.
Moreover, in the first SYNC pattern area 24-1 of the specific area 24, a unique first SYNC pattern signal defined in advance to indicate the start of the specific area 24 is detected when the light spot LS1 crosses the tracks 24G along the arrow AR11 even in the state in which the tracking servo is open. On the other hand, in the second SYNC pattern area 24-3 of the specific area 24, a unique second SYNC pattern signal defined in advance to indicate the end of the specific area 24 is detected when the light spot LS1 crosses the tracks 24G along the arrow AR11 even in the state in which the tracking servo is open.
As described above, the specific area 24 is provided in the guide layer 12. Thus, as detailed later, if the tracking servo pull-in is performed in the recording or reproduction of the optical disc 11, it is possible to start, continue, and stop the tracking servo pull-in operation without any problem by displacing the light spot LS1 in the radial direction so as to be displaced along the specific area 24. It is also possible to perform the start, continuation, and stop the track jump without any problem.
Incidentally, in the state in which the tracking servo is closed, continuous error detection and the track jump can be performed in the specific area 24. Namely, by using this portion, if the first SYNC pattern is normally detected even in the state in which the tracking servo is closed, it can be recognized that an area after the end of the detection of the first SYNC pattern is the groove area, and groove tracking is thus possible. Moreover, if the second SYNC pattern is detected, it can be recognized that a data recording area starts from the end of the detection of the second SYNC pattern.
Furthermore, due to the first SYNC pattern and the second SYNC pattern provided only in the tracks having the grooves, it is possible to distinguish whether the grooves are tracked or the lands are tracked, by detecting a RF signal (sum signal) in the detection of the first SYNC pattern, which remarkably improves robustness.
Next, with reference to
Incidentally, in this example, signals recorded in the servo area 22 and the pattern area 23 are provided in units of slots. Here, the “slot” is a logical section or division or a physical section or division obtained by dividing the track TR in the track direction. The slots are typically arranged continuously without gaps in the track direction and arranged without gaps in the radial direction or adjacently to each other. In this case, since control such as the tracking servo and the tilt servo is performed indirectly in the guide layer 12, the control becomes easy to be performed if a data format in the recording layer 13 is set to have a constant relation with the slot.
In
More specifically, one RUB is configured to correspond to the format of a BD-R (Blue ray Disc-Recordable: a Blue ray disc in which recording can be performed once).
Specifically, one RUB physically includes (248×(2×28)) physical clusters and logically includes three ADIP words (ADIP words NO. 1 to NO. 3).
One ADIP word consists of 83 ADIP units. One ADIP unit consists of 56 wobbles (wbl), which corresponds to two recording frames. The data to be recorded has a unit of 15 code words, i.e. nine nibbles. Therefore, one RUB is a section corresponding to 13944 wobbles.
Each of six address words (i.e. No. 1 to No. 6) included in one RUB has 74 address mark sub-units (servo mark sub-units) (i.e. A1 to A74). At the head of each servo mark word, a zero unit, which is 30 wbl, is disposed.
Moreover, each servo mark sub-unit consists of four slots. The first three slots (A Slots) are assigned to a slot for a servo mark (i.e. a “slot for a pre-format address”). The following one slot (B Slot) is assigned to a slot for the tilt detection (i.e. a slot for the tilt detection pattern). In other words, one servo mark sub-unit corresponds to the four slots in total, which are the three A Slots and the one B Slot, and thus includes {(1+8)×3}+(1+3)=31 wbl in total.
Thus, in the example, the length of one RUB is 2{(31×74)×3+(30×3)}=13944 wbl. Moreover, in the example, a length D of one wobble disposed at the head of each slot is set such that D=1 wbl>1.2 μm (the maximum diameter of the light spot).
As described above, in terms of a pre-address configuration example, six-address configuration is adopted for one RUB, and each address includes 70 units. It also includes address data (37 bits) and is (1 Slot Data)×37 Units=2 bits×37 Units=74 bits.
Incidentally, regarding the configuration of an ECC block, for example, by using 72 bits (=8 bits×9) out of 74 bits, 4 Bytes is used as an ECC code as 5 Bytes raw data.
For example, regarding codes C0, . . . , C9 (Parity C5, . . . , C8), a Reed-Solomon code is generated in the following manner.
Here, α is a primitive element.
G
p(x)=X8+X4+X3+X2+1
According to the configuration example in one RUB unit as described above, if the recording data format in another recording layer 13 complies with, for example, a BD-R format, the cycle of the wobbles provided for the servo area 22 has a predetermined integral ratio relation with a constituent unit of the data format in one recording layer. A section of the pattern area 23 and a position to be disposed thereof are also set to have a predetermined relation with the cycle of the wobbles. Thus, the predetermined position of the pattern area 23 can be specified from the wobble signal detected from the mark area of the servo area 22. Thus, a recording/reproducing apparatus described later can easily prepare timing to sample a specific parameter detection error.
In particular, even if a measure is taken to solve a new problem caused by that the first beam LB1 for reading the guide layer 12 is for lower-density than a reading beam for the BD-R format, data such as a pre-address required as a pre-format for recording can be formed by a desired information amount. Since a buffer area D (i.e. one portion of the mirror-surface area 21) for removing an influence by the beam diameter and the four slots are provided in one unit, and it is thus possible to remove an influence of the servo area 22 and the pattern area 23, which are disposed in adjacent tracks, when obtaining the pre-format data. It is also possible to remove the influence by the beam diameter of a pickup 102, thereby stably obtain the pre-format information.
In the example, in particular, the address sub-units A1 to A74 are alternately assigned to the outward path (i.e. for the recording layer for the outward path) and to the inward path (i.e. for the recording layer for the inward path).
In
For example, the value of m is determined from a predetermined condition. The servo area 22 is disposed at least in any one of the slots in one group. A condition for the arrangement (including the determination of the value of m) of the slots 300A (i.e. “A Slots”) will be explained later with reference to
In
In the servo area 22, the slots 300A (i.e. “A Slots (refer to FIG. 11)”) are arranged in the form that the sample servo marks 300S are widely distributed according to a predetermined rule, as described above. In the pattern area 23, slots 300B (i.e. “B Slots”) are arranged in a form of aligning substantially in the radial direction. Before or after the pattern area 23, three wobbles are ensured as an overlap area 400.
In the example, the length in the track direction of the tilt detection signal on the track TR and the length in the track direction of the constituent unit, such as an ECC block, a recording unit block (RUB), and an ADIP unit, in the format of data which is recorded into each of the recording layers 13 may be configured to have a predetermined integral ratio. In this manner, it becomes easy to maintain the frequency of generating the tilt detection signal and the cycle of recording the data into the recording layer 13 at a position in the recording surface corresponding to the track TR, in a constant relation, regardless of the radial position or the track position. In particular, if the zone CAV method is adopted, the tilt correction can be stably performed on the basis of the detected tilt detection signal at any radial position, even though an angular velocity varies depending on the radial position. Moreover, even if the zone CAV method is adopted, the stable tilt correction can be performed on the basis of the detected tilt detection signal without any problem in each zone.
In
Now, with reference to
As illustrated in
At this time, as the arrangement condition for the servo area 22, the slot 300A is disposed in at least one of “Slot 1” to “Slot m+1” so as not to overlap, in the radial direction, the servo areas 22 which are already arranged one track before (an inner-side adjacent track), two tracks before (an inner-side adjacent track of the track one track before), . . . , and m tracks before.
In the example, n=5 and m=2. Thus, the slot 300A is disposed in any of “Slot 1” to “Slot 3”. For example, regarding a slot 300A-1, as illustrated by a dashed-line arrow therefrom, it may be adaptively arranged from the “Slot 1” to “Slot 2”. For example, regarding a slot 300A-2, as illustrated by a dashed-line arrow therefrom, it may be adaptively arranged from the “Slot 1” to “Slot 3”.
By arranging the slots 300A and the slots 300B in the relation as illustrated in
In the pattern area 23, a predetermined specific parameter detection pattern for the pattern area 23 is formed such that a predetermined tilt error can be detected on the center track 23TR, with the seven tracks grouped in one group GR (refer to
In
As described above, the servo area 22 is disposed immediately before the center track TR in which the specific parameter detection error can be detected by the specific parameter detection pattern from among the seven tracks TR which belong to the pattern area 23, and it is thus possible to recognize that the first beam LB1 as a reading beam is located on the center track TR in which the specific parameter detection error can be detected. Therefore, it is possible to easily prepare the sample timing of detecting the specific parameter detection error.
On the other hand, if the first beam LB1 is not on the center track TR in one pattern area 23 composed of the plurality of tracks, the wobble signal detected by using the push-pull signal is detected with offset. Thus, it is possible to recognize that the first light beam is not on the center track TR.
In addition, in the example, the sample servo marks 300S are arranged in the separated slots in both the track direction and the radial direction (refer to
As illustrated in
Incidentally, regarding the configuration of the ECC block, for example, by using 192 bits (=8 bits×24) out of 206 bits, 12 Bytes raw data+12 Bytes is used as an ECC code.
Incidentally, in the example, one wobble is regarded as 69×2=138 channel bits. The first one wobble (in other words, one bit) of each slot may be assigned to the mirror-surface area 21 (refer to
Next, with reference to
In
Here, regarding a determination condition for “k”, “k” may be determined from the beam size, the track pitch for performing the recording into the recording layer, and the track in which amount of return light is influenced by the tilt. In the example, k=7. Regarding an arrangement condition of the pattern area 23, with respect to the slot 300A (i.e. “A Slot”).
the B Slot is disposed at a predetermined ratio (e.g. an arrangement ratio of A:B is 9:4 in the example).
With reference to
In
As the pre-address configuration for the outward path and the inward path, the pre-address corresponding to one RUB has a six-address configuration, including a three-address configuration for the outward path and a three-address configuration for the inward path. Each address consists of (74/2)=37 sub-units. The address data is (1 Slot Data)×(37 sub-units)=2 bits×37=74 bits. If the ECC configuration is configured as described above, it can be configured separately for the outward path and for the inward path.
As described above, according to the pre-address configuration example in the example, the tracks are concentric or spiral, and the outward path addresses and the inward path addresses are alternately arranged as the CAV method in the zone. Thus, in one format, a pre-format for outward path recording and a pre-format for inward path recording can be used in one guide layer.
For example, if the recording is performed from the inner circumference to the outer circumference, only the pre-format portion for the outward path is obtained as the address, while the pre-format address portions for the outward path and the inward path are used for tracking signal detection. In the recording, in the case of the concentric tracks, the recording is performed with a one-track jump. Alternatively, in the case of the spiral track, the recording is performed continuously. If the recording is performed from the outer circumference to the inner circumference, only the pre-format portion for the inward path is obtained as the address, while the pre-format address portions for the outward path and the inward path are used for the tracking signal detection. In the recording, in the case of the concentric tracks, the recording is performed with a one-track jump. Alternatively, in the case of the spiral track, the recording is performed with a two-track jump.
As explained above in detail with reference to
Particularly in the example illustrated in
In particular, as illustrated in
Particularly in the example illustrated in
Incidentally, in the example, the servo area 22 means an area in which the mark information is disposed, and the mark area is also used as the “guide area” or the “servo area” in the present invention. In other words, information for the tracking servo, such as the guide information or the sample servo mark, is also recorded in the servo area 22. In this sense, the servo area 22 can be also referred to as the “servo area 22”. The servo area 22 is an area having the two functions because both the mark information and the guide information are mixedly disposed.
Firstly, with reference to
In
In
As described above, even on the premise of the concentric tracks TR, if the recording is performed from the inner circumference to the outer circumference and if the recording is performed from the outer circumference to the inner circumference, the track jump TJ allows the reciprocating recording operation to be performed without any problem.
Next, with reference to
In
In
As described above, even on the premise of the spiral track TR, if the recording is performed from the inner circumference to the outer circumference and if the recording is performed from the outer circumference to the inner circumference, the track jump TJ allows the reciprocating recording operation to be performed without any problem.
Incidentally, using only the three areas illustrated in
In the example, however, by providing the specific area 24 as explained with reference to
Next, with reference to
In
The recording/reproducing apparatus 10 is provided with: an optical pickup 102; a signal recording/reproducing unit 103; a spindle motor 104; a bus 106; a CPU (drive control unit) 111; a memory 112; and a data input/output control unit 113. In the recording, the first beam LB1 and the second beam LB2 are irradiated via the objective lens 102L (refer to
The host computer 201 is provided with: an operation/display control unit 202; an operation button 202; a display panel 204; a bus 206; a CPU 211; a memory 212; and a data input/output control unit 213. In the recording, the data to be recorded is inputted from the data input/output control unit 213. In the reproduction, reproduced data is outputted from the data input/output control unit 213.
The optical pickup 102 is provided with: a red semiconductor laser for emitting the first beam LB1; a blue semiconductor laser for emitting the second beam LB2; and a synthesis/separation optical system provided with a prism, a mirror, or the like including the objective lens 102L. The optical pickup 102 is configured to irradiate the first beam LB1 and the second beam LB2 via the common objective lens 102L, coaxially and with different focuses (refer to
Moreover, the optical pickup 102 includes: a light receiving element such as a two-division or four-division CCD for receiving reflected light from the optical disc 11 caused by the first beam LB1 via the objective lens 102L; and a light receiving element such as a two-division or four-division CCD for receiving reflected light from the optical disc 11 caused by the second beam LB2 via the objective lens 102L. The optical pickup 102 can modulate the second beam LB2 at recording intensity which is relatively high in the recording and can set the second beam LB2 at reproduction intensity which is relatively low in the reproduction.
The optical pickup 102 and the signal recording/reproducing unit 103 are configured to generate the tracking error signal, for example, by a push-pull method or differential phase detection (DPD), and to further reproduce the pre-pit signal or the address information, by using a light receiving signal from the light receiving element for receiving the reflected light from the guide layer 12, at least in the recording.
The optical pickup 102 and the signal recording/reproducing unit 103 are configured to generate the tracking error signal, for example, by the push-pull method or differential phase detection, and to generate, for example, a data signal as a signal corresponding to the entire quantity of light, by using a light receiving signal from the light receiving element for receiving the reflected light from the recording layer 13, at least in the reproduction.
Alternatively, the optical pickup 102 and the signal recording/reproducing unit 103 are configured to generate the tracking error signal by using the light receiving signal from the light receiving element for receiving the reflected light from the guide layer 12 and to generate the data signal by using the light receiving signal from the light receiving element for receiving the reflected light from the recording layer 13, in the reproduction.
The memory 112 and the memory 212 are used as occasion demands to temporarily or permanently hold (i) a computer program for controlling each element such as the CPU 111 of the recording/reproducing apparatus 101 and each element such as the CPU 211 of the host computer 201 so as to perform a recording/reproducing operation explained below and (ii) various data such as control data, processing data, and processed data, required for the recording/reproducing operation, via the bus 106, the bus 206, or the like.
Particularly in the example, the recording/reproducing apparatus 101 is further provided with a correction mechanism 105. The correction mechanism 105 is one example of the “processing device” of the present invention and is typically a tilt correction mechanism. The correction mechanism 105 may be various correction mechanisms, such as a mechanism for eccentricity correction of the optical disc 11, a mechanism for inclination correction of a disc surface, a mechanism for aberration correction of an optical system, a mechanism for phase difference correction of a light beam, a mechanism for distortion correction, a mechanism for light absorption correction, and a mechanism for setting of a strategy, in addition or instead of the tilt correction mechanism. By the correction mechanism 105, a particular type of processing (typically, the tilt correction) is performed on the optical pickup 102, on the basis of the pattern signal (typically, the tilt detection signal) detected from the guide layer 12. For example, in the case of the tilt correction, it is performed every time the tilt detection signal is detected, and the tilt servo is locked in a period until the next tilt detection signal is detected.
Now, with reference to
In
Firstly, the push-pull signal from the light receiving element of the optical pickup 102 is inputted to each of the LPF 121 and the LPF 131, and a high-frequency noise is cut.
Then, on one hand, an output signal with the high-frequency noise cut on the LPF 131 is subject to wobble detection by the wobble detector 132, and oscillation is performed on the oscillator 133 at a frequency corresponding to the detected wobble.
As illustrated in
In
On the other hand, an output signal with the high-frequency noise cut on the LPF 121 is sampled, held, and further smoothed by the sampling & holding & smoothing circuit 122. At this time, the timing of the sampling is based on the sample timing signal generated by the sample timing generation circuit 134. As illustrated in
Output signals, which are a sample 1 and a sample 2 from the sampling & holding & smoothing circuit 122, are subtracted, integrated, and further held by the operation (subtraction) & integration & holding circuit 123. As a result, a specific parameter error signal is generated, for example, as the pattern signal which makes one pattern by covering the seven tracks, or on the basis of the pattern signal obtained in this manner.
If the specific parameter error signal is inputted to the correction mechanism 105, a driving operation on the correction mechanism 105 is performed in accordance with characteristics, such as a value of the signal, a positive or negative sign, or the degree of modulation. For example, in the case of the tilt correction, the driving is performed so as to reduce a tilt error by using an actuator for the tilt correction.
Hereinafter, with reference to
In
Then, an operation start command according to operation performed on the operation button 203 by the user while watching the display panel 204 is issued by the operation/display control unit 202 and the CPU 111 on the drive side and the CPU 211 on the host side or the like. In response to the operation start command, under the control by the signal recording/reproducing unit 103, the rotation of the optical disc 11 is started by the spindle motor 104. Before or after this, under the control by the signal recording/reproducing unit 103, light irradiation by the optical pickup 102 is started. Moreover, a reading servo system for the guide layer 12 is operated. In other words, the first beam LB1 is irradiated and focused on the guide layer 12, by which the tracking operation is started (step S12).
Incidentally, the transfer of various commands including the operation start command and the various data including user data and control data is performed via the bus 206 and the data input/output control unit 213 on the host side and the bus 106 and the data input/output control unit 113 on the drive side.
Then, the irradiation onto the tracks TR by the first beam LB1 is kept on the guide layer 12, and the wobble signal and the pre-pit signal (moreover, the tracking error signal obtained from at least one of these signals by the push-pull method or DPD) are detected from the servo area 22. Moreover, disc management information recorded in advance as at least one of these signals is obtained by the CPU 111 on the drive side or the CPU 211 on the host side or the like.
Incidentally, the disc management information may be collectively recorded and read in a lead-in area, a table-of-content (TOC) area, and the like which are located on the innermost circumferential side of the guide layer 12. The content may comply with the disc management information of the existing DVD, BR disc, or the like. Management information may be recorded in advance or separately previously, in the lead-in area, the TOC area, and the like which are specially provided for the recording layers, and this may be read at this time point or an arbitrary time point.
Then, it is judged whether or not operation required by the CPU 111 on the drive side or the CPU 211 on the host side or the like is data recording (step S14). If it is the data recording (the step S14: Yes), recording processing for a new optical disc 11 is performed (step S15). The recording processing will be detailed later (refer to
On the other hand, if it is not the data recording in the judgment in the step S14 (the step S14: No), or if the recording processing for the new optical disc 11 is completed in the step S15, it is judged whether or not the operation required by the CPU 111 on the drive side or the CPU 211 on the host side or the like is data reproduction (step S16). Here, if it is the data reproduction (the step S16: Yes), reproduction processing for the new optical disc 11 is performed (step S17). The reproduction processing will be detailed later (refer to
If it is not the data reproduction in the judgment in the step S16 (the step S16: No), or if the reproduction processing for the new optical disc 11 is completed in the step S17, it is judged whether or not ejection, i.e. tray ejection or the like, is required via the operation button 203 or the like (step S18). Here, if the ejection is not required (the step S18: No), the operational flow returns to the step S14, and the subsequent steps are performed again.
On the other hand, if the ejection is required in the judgment in the step S18 (the step S18: No), the ejection operation is performed (step S19), and a series of recording/reproducing processing for the optical disc 11 is completed.
Next, with reference to
In
Then, a zone of the optical disc 11 in the zone CAV method is judged, and spindle servo control is performed in accordance with the judged zone to set a rotational speed suitable for the zone (step S21b).
Then, under the control by the CPU 111 and the signal recording/reproducing unit 103, focus servo by the second beam LB2 is performed by the optical pickup 102 on the desired recording layer 13 to record the data therein (step S22).
Then, the tracking servo for the tracks TR by the first beam LB1 is kept in a state in which the focus servo by the second beam LB2 is closed, by the optical pickup 102. In other words, the tracking servo for the desired recording layer 13 is performed indirectly by the tracking servo for the guide layer 12 (step S23a).
Then, correction is performed on the correction mechanism 105 on the basis of a specific parameter detection result (refer to
The correction in the step S23b may be performed, at least partially, in a process of recording the data in a next step S23c.
Then, the data recording into the desired recording layer 13 is started by irradiating the second beam LB2 with it modulated in accordance with the value of the data to be recorded (step S23c).
Then, it is judged whether or not the optical pickup 102 reaches a track change position by the CPU 111 or the like (step S201). Here, if the optical pickup 102 reaches the track change position (the step S201: Yes), the track jump is performed (step S202).
Then, it is judged whether or not the optical pickup 102 reaches a zone change position by the CPU 111 or the like (step S203). Here, if the optical pickup 102 reaches the zone change position (the step S203: Yes), the spindle servo control is performed to set a rotational speed corresponding to a new zone, and the rotational speed suitable for the zone is set (step S204).
After the step S204, or if the optical pickup 102 does not reach the zone change position in the judgment in the step S203 (the step S203: No), or if the optical pickup 102 does not reaches the track change position in the judgment in the step S201 (the step S201: No), then, the recording of the data into the recording layer 13 is continued (step S205).
Then, it is monitored whether or not a predetermined amount of recording is ended by the CPU 111 or the like (step S24). Here, unless the recording is ended, the data recording into the recording layer 13 is continued (the step S24: No).
Here, if the recording is ended (the step S24: Yes), the management information is updated in accordance with the recorded data (step S25). The management information may be collectively recorded in the lead-in area, the TOC area, or the like which is provided for at least one of the plurality of recording layers 13. The position may be on the inner circumferential side, but may be on the outer circumferential side or in the middle, or may be recorded in a somewhat dispersed form. In addition to or instead of this, management information provided for the memory 112, the memory 212, or the like and linked to the optical disc 11 may be updated.
This is the completion of the series of recording processing for the new optical disc 11 (the step S15 in
Next, with reference to
In
Then, the focus servo by the second beam LB2 is performed on the desired recording layer 13 to reproduce the data therefrom by the optical pickup 102, under the control by the CPU 111 and the signal recording/reproducing unit 103, while the tracking servo remains performed (step S42).
Then, the data reproduction from the desired recording layer 13 is started by receiving the reflected light caused by the second beam LB2 via the objective lens 102L, in a state in which the tracking servo by the first beam LB1 is closed and the focus servo by the second beam LB2 is closed, by the optical pickup 102 (step S43).
Then, it is monitored whether or not a predetermined amount of reproduction is ended by the CPU 111 or the like (step S44). Here, unless the reproduction is ended, the data reproduction from the recording layer 13 is kept (the step S43: No).
Here, if the reproduction is ended (the step S44: Yes), the series of reproduction processing for the new optical disc 11 (the step S17 in
Incidentally, as a modified example of the reproduction processing illustrated in
Next, tracking servo pull-in processing will be explained with reference to a flowchart in
In
Firstly, during the recording or during the reproduction, it is monitored whether or not a first SYNC signal “SYNC1” from the first SYNC pattern area 24-1 (refer to
Then, it is monitored whether or not the tracking servo pull-in is completed (step S143).
Here, while the pull-in is not completed (the step S143: NO), it is monitored whether or not a second SYNC signal “SYNC2” from the second SYNC pattern area 24-3 (refer to
In other words, there is no problem if the servo pull-in operation is completed before the second SYNC signal “SYNC2” is detected; however, even if the servo pull-in operation is not completed, the end of the specific area 24 can be recognized by detecting the second SYNC signal “SYNC2”. Thus, the current servo pull-in operation using the specific area 24 is forcibly terminated, and another option can be performed without a delay, including performing the servo pull-in operation again in the next cycle.
On the other hand, while the second SYNC signal is not detected (the step S144: NO), the operational flow returns to the step S142, and the servo pull-in operation is continued.
In the judgment in the step S143, if it is confirmed that the pull-in is completed (the step S143: YES), the pull-in is regarded as being safely completed, and a series of processing regarding the tracking servo pull-in is ended. By this, the tracking servo for a target track is closed, and the subsequent tracking operation and the like in the recording and the reproduction are continued.
Next, track jump processing will be explained with reference to a flowchart in
In
In
Then, by the judgment of the RF signal (sum signal) corresponding to the pattern from the first SYNC pattern area 24-1 to the body area 24-2 (refer to
Here, if it is judged “soon to be the groove” (the step S54), the groove tracking is turned on (step S55), and a half track jump is started (step S56).
Then, the pattern in the body area 24-2 (refer to
If the zero-cross is confirmed (the step S57: YES), the half track jump is ended, and land tracking is turned on (step S58).
Alternatively, if it is judged “soon to be the land” (the step S64), the land tracking is turned on (step S65), and the half track jump is started (step S66).
Then, the pattern in the body area 24-2 (refer to
If the zero-cross is confirmed (the step S67: YES), the half track jump is ended, and the groove tracking is turned on (step S68).
As described above, a series of processing regarding the track jump is ended. By this, the tracking servo for the target track is closed, and the subsequent tracking operation and the like in the recording and the reproduction are continued.
As explained in detail with reference to
In particular, in the example, by providing the specific area 24 immediately before a portion in which the arrangement of ECCs of the data to be recorded into the recording layer 13 is aligned in the radial direction, it is possible to recognize the specific area 24 and obtain timing to perform the track jump in either case of recording from the inner circumference to the outer circumference or from the outer circumference to the inner circumference.
Incidentally, in the body portion of the specific area 24, the alternate configuration of the grooves and the lands is adopted, and thus, the jump to the adjacent track can be performed easily in any position.
Moreover, in the first SYNC pattern area 24-1, there is disposed the unique pattern that can be detected even in the state in which the tracking servo is open. Thus, the start of the specific area 24 can be detected in the pull-in, in the state in which the tracking servo is open. Moreover, more preferably, by providing a distance between the grooves in the alternate configuration of the grooves and the lands disposed in the body area 24-2, it is possible to certainly obtain a signal crossing the tracks and to facilitate the servo pull-in.
In addition, in the second SYNC pattern area 24-3, there is disposed the unique pattern that can be detected even in the state in which the tracking servo is open. Thus, even in a state in which the tracking servo pull-in is not performed, it is possible to recognize the end position of the specific area 24, and to change to the servo pull-in method according to the following area.
Moreover, the pattern area is disposed, with the plurality of tracks as one group GR. Thus, free or arbitrary arrangement is possible in the integrated (grouped) tracks, and the degree of freedom can be ensured in the arrangement of specific parameter detection points, such as tilt error detection points, which can be detected by the recording/reproducing apparatus 101. One pattern area 23 and another adjacent pattern area 23 are independent of each other. Thus, it is possible to dispose the specific parameter detection patterns, such as the tilt detection patterns, independently of each other, and arrangement with the degree of freedom is possible throughout the entire surface of the optical pickup 11 as a whole.
As the guide layer 12, the arrangement in this format can realize easy-reading and extremely advantageous arrangement for the recording/reproducing apparatus 101 which simultaneously reads the plurality of tracks TR which are densified, because the pattern area 23 is disposed with the simultaneously read plurality of tracks TR as one group GR.
Moreover, the servo area 22 is formed by wobbling the grooves in the guide layer 12. Thus, the recording/reproducing apparatus 101 can recognize the accurate position of the pattern area 23 (refer to
Next, with reference to
As illustrated in
In the error detector 301, a disturbance for the tracking servo is inputted, and a feedback signal from the actuator 304 is subtracted (minus added), and a subtracted signal is outputted. The subtracted signal from the error detector 301 is inputted to the sampler 302.
The sampler 302 is configured as a so-called “zero-order hold circuit” for holding a sample value. Specifically, there are provided: the sampling switch which is configured to close at sampling timing; the capacitor for holing it; and the buffer. In the sampler 302, the subtracted signal is sampled by the sampling switch at sampling timing according to a frequency band for operating the tracking serve, is further held by the capacitor, and is buffered by the buffer. The sampling timing is generated by a mark signal, such as, for example, the wobble signal and the pre-pit signal, detected by the light receiving element for receiving the first beam LB1. Incidentally, a method of generating the sampling timing is not limited to this, and the sampling timing may be generated in accordance with a medium configuration in a modified example or the like described later. Moreover, the configuration of the sampler 302 is also not limited to this and may be a “first-order hold circuit” or the like.
The buffer output from the sampler 302 as sampled above is amplified and equalized by the amplifier and equalizer 303 and is further inputted to the actuator 304.
In accordance with the inputted amplified signal, the irradiation position of the first beam LB1 on the guide layer 12 (therefore, the irradiation position of the second beam LB2 on one recording layer 13) provided in the optical pickup 102 is moved in the radial direction by the actuator 304. From the actuator 304, the feedback signal according to the variation thereof is fed back to the error detector 301.
Now, in particular, with reference to
From
In the case of this example explained with reference to
That is, if a tracking servo band is set to, for example, 2.4 KHz, a time interval T is obtained as T=1/(24×103)=46.7 [μsec] corresponding to 24 kHz which is about 10 times in order to ignore an influence by the sampler 302 realized as the hold circuit described above. From a relation between the time interval T and a rotational linear velocity by the spindle motor 104, the longest distance required as the arrangement interval or the arrangement pitch (refer to
For example, if a linear velocity v is set to 4.917 m/sec, a predetermined distance L is obtained as L=v×T≈230 [μsec]. In other words, if one servo area 22 is put in five slots along the track TR, a slot configuration is determined such that the length of the five slots is shorter than 230 [μm], or how many slots are used to put one servo area 22 is determined.
Incidentally, the method of determining the arrangement interval (i.e. arrangement pitch) of the servo areas 22 is not limited to this example, and the arrangement interval may be determined in view of the servo band required as illustrated in
Hereinafter, various modified examples of the example will be explained with reference to
In
According to the modified example, firstly, if the first SYNC pattern is detected in the state in which the tracking servo is closed, the following area is expected to be the land area. Thus, in order to perform the tracking servo on the lands, polarity of the tracking servo may be reversed in comparison with the case of the example described above (refer to
Next, if the tracking servo is open, as in the case of the example described above (refer to
As described above, even in the modified example, basically, the same effect as in the case of the example described above (refer to
In
In
Moreover, the first SYNC pattern area 24-1, the body area 24-2, and the second SYNC pattern area 24-3 are sequentially arranged, not to overlap one another on adjacent three tracks.
According to the modified example, as illustrated in
Next, if the tracking servo is open, the track cross signal can be detected and the pull-in operation is facilitated, and the purpose can be thus achieved. The track in which the tracking servo can be actually closed is slightly restricted or limited in comparison with the example; however, there is no practical problem.
As described above, even in the modified example, basically, the same effect as in the case of the example described above (refer to
In
According to the modified example, substantially, in addition to the same effect as in the case of the example described above (refer to
Next,
In
For example, if it is set to perform the recording and reproduction from the inner circumference to the outer circumference in the first layer of the recording layers and to perform the recording and reproduction from the outer circumference to the inner circumference in the second layer of the recording layers, then, a time to change the recording and reproduction between the two layers is almost a time to perform a layer jump. Thus, it is extremely useful in the recording and reproduction which are continuously performed by straddling the plurality of recording layers. In other words, it is possible to obtain the same effect as that of so-called “opposite recording” or “opposite reproduction” in a dual-layer disc. That is, if the data that is continuous in real time such as video data is recorded as the data to be recorded, by using the optical disc 11 in the modified example, then, it takes the time for the layer jump, to reach from the end of the first recording layer to the start of the second recording layer, in the reproduction. This is extremely useful in view of the layer jump and a time for returning the position of the optical pickup 102 from the outer circumference to the inner circumference, which is further added in the case of the example illustrated in
As described above, by using the modified example in
As explained above in detail, according to the example and the modified examples, the arrangement interval (arrangement pitch) of the servo areas 22 along the tracks TR is set to be less than or equal to the predetermined distance, and moreover, the servo areas 22 are (discretely) arranged on the entire surface of the optical disc 11. Thus, the continuous tracking signal can be obtained by the sampling at any position from the inner circumference to the outer circumference of the optical disc 11 in the guide layer 12.
In addition, one cycle of wobble WB and the constituent unit of the data format in one recording layer 13 have an integral multiple relation, and the slots are configured as an integral multiple of the one cycle of wobble WB, and the servo area 22 corresponds to this section. This facilitates the appropriate arrangement not to overlap the servo areas 22 on the adjacent tracks TR (i.e. not to cause the crosstalk in the wobble signal and the pre-pit signal). The wobble signal obtained in this manner can be used as the generation of a timing reference signal excellent in robust, or the generation of a timing signal at the start of the recording, via a phase locked loop (PLL) circuit.
Moreover, the present invention is not limited to the aforementioned embodiment, but various changes may be made, if desired, without departing from the essence or spirit of the invention which can be read from the claims and the entire specification. An information recording medium, an information recording apparatus and method, and an information reproducing apparatus and method, which involve such changes, are also intended to be within the technical scope of the present invention.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2010/056625 | 4/13/2010 | WO | 00 | 10/22/2012 |
