Patent Application
20150131424
The present invention relates to a device, a method, and a medium for recording and/or reproducing information using holography.
Currently, an optical disk having a recording density of about 100 GB even for consumer use can be produced commercially on the basis of Blu-ray Disc™ specification using blue-violet semiconductor laser. In the future, an optical disk is also desired to attain a high capacity of more than 500 GB. However, in order to achieve such extremely high density with an optical disk, it is required to have a high density technique according a new method different from a conventional high density technique which is a shorter wave length and a higher NA of a an object lens.
While next generation storage technique is researched, hologram recording technique for recording digital information using holography attracts attention. An example of hologram recording technique includes Japanese Patent Application 2004-272268 (PTL 1). This publication describes a so-called angle multiplexed recording method for performing multiplexed recording by displaying multiple page data on a spatial light modulation device while changing the incidence angle of the reference light into an optical information recording medium. Further this publication describes a technique for reducing the interval of adjacent holograms by condensing a signal light with a lens and arranging a diaphragm (spatial filter) at a beam waist thereof.
An example of hologram recording technique includes International Publication No. WO2004-102542 (PTL 2). This publication describes an example using a shift multiplexed method for recording a hologram by adopting a light from inner pixels as a signal light and a light from outer circular belt-like pixels as a reference light in a single spatial light modulation device, condensing both of the light beams onto an optical information recording medium using the same lens, and causing the signal light and the reference light to be interfered with each other at a position close to the focal plane of the lens.
An example of an adjustment technique of a recording condition during hologram recording includes Japanese Patent Application Laid-Open No. 2005-50522 (PTL 3). This publication recites in order to form a recording pattern of a desired diffraction efficiency using DRAW function, a test area is provided on the optical information recording medium 1 as necessary.”
PTL 1: Japanese Patent Application Laid-Open No. 2004-272268
PTL 2: International Publication No. WO2004-102542
PTL 3: Japanese Patent Application Laid-Open No. 2005-50522
By the way, an optical information recording/reproduction device using holography has a problem in that the signal-to-noise ratio (SNR) during reproduction decreases, unless the condition during recording is adjusted, because of variation in the environment during recording, variation of components such as laser output, variation of production of the device, and the like.
However, PTL 3 does not disclose any specific standard during adjustment of the recording condition.
The present invention is made in view of the above problems, and it is an object of the present invention to provide an optical information recording/reproduction device capable of recording a high quality hologram by appropriately adjusting a recording condition before recording, and to provide a method, and a medium therefor.
The above problem is solved by the invention described in claims, for example.
According to the present invention, for example, an optical information recording/reproduction device capable of recording a high quality hologram in a holographic memory can be provided, and a method and a medium therefor can be provided.
a) to 6(c) are schematic diagrams illustrating an embodiment of an operation flow of the optical information recording/reproduction device.
a) and 9(b) are schematic diagrams illustrating an embodiment of an operation flow of the signal generation circuit and signal processing circuit.
FIGS. 10(1) and 10(2) are schematic diagrams illustrating an embodiment of a layer structure of an optical information recording medium having a reflection layer.
a) and 11(b) are schematic diagrams illustrating an example of relationship of a reproduction light intensity and a reference light angle in an optical information recording/reproduction device.
Hereinafter, embodiments of the present invention will be explained with reference to drawings.
A first embodiment according to the present invention will be explained with reference to
An optical information recording/reproduction device 10 is connected via an input/output control circuit 90 to an external control device 91. When the optical information recording/reproduction device 10 performs recording, the optical information recording/reproduction device 10 causes the input/output control circuit 90 to receive an information signal, which is to be recorded, from an external control device 91. When the optical information recording/reproduction device 10 performs reproduction, the optical information recording/reproduction device 10 causes the input/output control circuit 90 to transmit the reproduced information signal to the external control device 91.
The optical information recording/reproduction device 10 includes a pickup 11, a reproduction reference light optical system 12, a cure optical system 13, a disk rotation angle detection optical system 14, and a rotation motor 50. An optical information recording medium 1 is configured to be rotatable with the rotation motor 50.
The pickup 11 is configured to emit a reference light and a signal light to the optical information recording medium 1, and records digital information to a recording medium by using holography. At this occasion, the information signal to be recorded is sent by a controller 89 via a signal generation circuit 86 into a spatial light modulation device provided in the pickup 11, so that the signal light is modulated by the spatial light modulation device.
When information recorded on the optical information recording medium 1 is reproduced, light wave for causing the reference light emitted from the pickup 11 to be incident upon the optical information recording medium in the direction opposite to recording is generated by the reproduction reference light optical system 12. The reproducing light reproduced by the reproduction reference light is detected by a light detection device explained later provided in the pickup 11, and the signal is reproduced by a signal processing circuit 85.
The recording condition adjustment circuit 92 inputs the information of the reproduction signal from the pickup 11, calculates the optimum exposure light energy density during recording, and outputs the optimum exposure light energy density to the controller 89. For example, the adjustment of the recording condition is performed in a predetermined area provided for recording condition adjustment on the disk, and in this specification, the disk area for the recording condition adjustment will be referred to as an adjustment area. This adjustment is processing similar to OPC (Optical Power Control) performed with a conventional bit-by-bit recording optical disk, and for example, the laser power density and the exposure light time during recording are adjusted. In the adjustment of the exposure light energy density, the adjustment may be performed by changing only the laser power density, or may be performed by changing only the exposure light time, or may be performed by changing both of the laser power density and the exposure light time. However, in order to stabilize the output and the coherence of the laser, a method for performing adjustment by changing the exposure light time may be desired. Information about pre-adjustment recording condition may be, for example, saved in advance in an optical information recording/reproduction device, a device for controlling an optical information recording/reproduction device, or an optical information recording medium, or a cartridge storing an optical information recording medium. In this case, the information about pre-adjustment recording condition may be, for example, information such as a recommended wavelength and an exposure light energy density of a pre-cure light source explained later as shown in
The emission times of the reference light and the signal light emitted to the optical information recording medium 1 can be adjusted by controlling the open/close time of the shutter in the pickup 11 via a shutter control circuit 87 with the controller 89.
The cure optical system 13 is configured to generate the light beam used for pre-cure and post-cure of the optical information recording medium 1. The pre-cure is preprocessing for emitting a predetermined light beam in advance before the reference light and the signal light are emitted to a desired position when information is recorded to the desired position in the optical information recording medium 1. The post-cure is post-processing for emitting a predetermined light beam to the desired position so as to disable appending after the information is recorded to the desired position in the optical information recording medium 1.
The disk rotation angle detection optical system 14 is used to detect the rotation angle of the optical information recording medium 1. In a case where the optical information recording medium 1 is adjusted in a predetermined rotation angle, the disk rotation angle detection optical system 14 detects a signal according to a rotation angle, so that the rotation angle of the optical information recording medium 1 can be controlled using the detected signal via a disk rotation motor control circuit 88 with the controller 89.
A predetermined light source driving electric current from a light source driving circuit 82 is provided to light sources in the pickup 11, the cure optical system 13, and the disk rotation angle detection optical system 14, and each light source can emit light beam with a predetermined light quantity.
The pickup 11 and the disk cure optical system 13 are provided with mechanisms capable of sliding the position in the radius direction of the optical information recording medium 1, and the position control is performed via an access control circuit 81.
By the way, in the recording technique using the principle of angle multiplex of the holography, the allowable error tends to be extremely small with respect to deviation of the reference light angle.
Therefore, it is necessary to provide a mechanism in the pickup 11 for detecting the deviation quantity of the reference light angle, and to provide a servo mechanism in the optical information recording/reproduction device 10 to cause a servo signal generation circuit 83 to generate a signal for servo control and correct the deviation quantity via a servo control circuit 84.
Several optical system configurations and all the optical system configurations of the pickup 11, the cure optical system 13, and the disk rotation angle detection optical system 14 may be combined into one to be simplified.
The light beam having passed through the PBS prism 305 serves as a signal light 306, and after the light beam diameter is enlarged by a beam expander 308, the light beam passes through a phase mask 309, a relay lens 310, and a PBS prism 311, and is incident upon a spatial light modulation device 312.
A signal light having information given thereto by the spatial light modulation device 312 is reflected by the PBS prism 311, and the signal light propagates through the relay lens 313 and the spatial filter 314. Thereafter, the signal light is condensed by the object lens 315 onto the optical information recording medium 1.
On the other hand, the light beam reflected by the PBS prism 305 serves as a reference light 307, and after the light beam is set in a predetermined polarization direction according to recording or reproduction by a polarization direction conversion device 316, the light beam is incident upon a galvano mirror 319 via a mirror 317 and a mirror 318. The angle of the galvano mirror 319 can be adjusted by an actuator 320, and therefore, the incidence angle of the reference light incident upon the optical information recording medium 1 after passing through the lens 321 and the lens 322 can be set to a desired angle. In order to set the incidence angle of the reference light, a device for converting the wave plane of the reference light may be used instead of the galvano mirror. In this specification, the reference light angle is such that, for example, as shown in the drawing, where a direction perpendicular to the optical information recording medium is zero degrees, a direction in which there is a larger scanning range of the reference light angle within a plane in which at least two or more reference lights of which angles are changed by the actuator 320 exist is defined as + direction, and the opposite direction is defined as − direction.
As described above, the signal light and the reference light are incident on the optical information recording medium 1 so that the signal light and the reference light overlap each other, whereby an interference fringe pattern is formed in the recording medium, and this pattern is written to the recording medium, so that the information is recorded. The galvano mirror 319 can change the incidence angle of the reference light incident upon the optical information recording medium 1, and therefore the information can be recorded by the angle multiplex.
Thereafter, in the hologram recorded by changing the reference light angle in the same area, a hologram corresponding to each reference light angle will be called a page, and a set of pages angle-multiplexed in the same area will be called a book.
The reproduction light reproduced by the reproduction reference light propagates the object lens 315, the relay lens 313, and the spatial filter 314. Thereafter, the reproduction light passes through the PBS prism 311, and is incident upon the light detection device 325, so that the recorded signal can be reproduced. The light detection device 325 may be an image-capturing device such as a CMOS image sensor and a CCD image sensor. But it may be any device as long as it can reproduce page data.
The light beam having passed through the PBS prism 505 is incident upon a spatial light modulation device 508 by way of a PBS prism 507. A signal light 506 having information given thereto by the spatial light modulation device 508 is reflected by the PBS prism 507, and the signal light 506 propagates through an angle filter 509 that allows only light beam of a predetermined incidence angle to pass through. Thereafter, the signal light beam is condensed by the object lens 510 onto the hologram recording medium 1.
On the other hand, the light beam reflected by the PBS prism 505 serves as a reference light 512, and after the light beam is set in a predetermined polarization direction according to recording or reproduction by a polarization direction conversion device 519, the light beam is incident upon the lens 515 via the mirror 513 and the mirror 514. The lens 515 is configured to condense the reference light 512 onto the backfocus plane of the object lens 510, and the reference light once condensed on the backfocus plane of the object lens 510 is again made into parallel light by the object lens 510, and is incident upon the hologram recording medium 1.
In this case, the object lens 510 or optical block 521 can be driven, for example, in a direction indicated by reference sign 520, and the position of the object lens 510 or the optical block 521 is shifted along the driving direction 520, so that the relative position relationship changes between the object lens 510 and the focal point in the backfocus plane of the object lens 510, and therefore, the incidence angle of the reference light incident upon the hologram recording medium 1 can be set in a desired angle. Instead of driving the object lens 510 or the optical block 521, the incidence angle of the reference light may be set in a desired angle by driving the mirror 514 with the actuator.
As described above, the signal light and the reference light are incident on the hologram recording medium 1 so that the signal light and the reference light overlap each other, whereby an interference fringe pattern is formed in the recording medium, and this pattern is written to the recording medium, so that the information is recorded. The position of the object lens 510 or the optical block 521 is shifted along the driving direction 520, whereby the incidence angle of the reference light incident upon the hologram recording medium 1 can be changed, and therefore the information can be recorded by the angle multiplex.
When the recorded information is reproduced, the reference light is incident upon the hologram recording medium 1 as described above, and the light beam having passed through the hologram recording medium 1 is reflected by the galvano mirror 516, whereby the reproduction reference light is generated. The reproduction light reproduced by the reproduction reference light propagates through the object lens 510 and the angle filter 509. Thereafter, the reproduction light passes through the PBS prism 507, and is incident upon the light detection device 518, so that the recorded signal can be reproduced.
The optical system as shown in
a) to 6(c) illustrate an operation flow of recording and reproduction in the optical information recording/reproduction device 10. In this case, in particular, a flow of recording/reproduction using holography will be explained.
a) is an operation flow from when the optical information recording medium 1 is inserted into the optical information recording/reproduction device 10 and to when the preparation for the recording or the reproduction is completed.
When the medium is inserted as shown in
When the medium is determined to be an optical information recording medium for recording or reproducing digital information using holography as a result of the disk determination, the optical information recording/reproduction device 10 reads control data provided in the optical information recording medium (603), for example, the optical information recording/reproduction device 10 obtains information about the optical information recording medium, and for example, information about various kinds of setting conditions during recording and reproduction.
After the control data are read, various kinds adjustment according to the control data and learning processing of the pickup 11(604) are performed, and the optical information recording/reproduction device 10 finishes the preparation of recording or reproducing (605).
In the operation flow from the preparation completion state to when the information is recorded, first, as shown in
Thereafter, in order to record high quality information to an optical information recording medium, various kinds of learning processing for recording such as the power density optimization of the light source 301 and the optimization of the exposure light time with the shutter 303 are performed in advance as necessary (612).
Thereafter, in the seek operation (613), the access control circuit 81 is controlled to move the position of the pickup 11 and the cure optical system 13 to a predetermined position of the optical information recording medium. In a case where the optical information recording medium 1 has address information, the address information is reproduced, and the following operation is repeated: a determination is made as to whether the position has been moved to the target position, and if the position is not arranged at the target position, the deviation quantity from the predetermined position is calculated, and the positioning is performed again.
Thereafter, a predetermined area is pre-cured using the light beam emitted from the cure optical system 13 (614), and the reference light and the signal light emitted from the pickup 11 are used to record the data (615).
After the data are recorded, the post-cure is performed using the light beam emitted from the cure optical system 13 (616). As necessary, the data may be verified.
In the operation flow from the reparation completion, state to when the recorded information is reproduced, as shown in
Thereafter, the reference light is emitted from the pickup 11, and information recorded in the optical information recording medium is read out (622), and the reproduction data are transmitted (613).
a) and 9(b) illustrate a data processing flow during recording and reproduction.
The data processing during recording will be explained with reference to
Subsequently, a data processing flow during reproduction will be explained with reference to
When the output control circuit 90 starts input of the user data, the input/output control circuit 90 notifies the controller 89 that the input of the user data is started. The controller 89 receives this notification, and commands the signal generation circuit 86 to perform recording processing to record data for one page which are input from the input/output control circuit 90. The processing command given by the controller 89 passes through a control line 708, and notified to a sub-controller 701 in the signal generation circuit 86. Upon receiving this notification, the sub-controller 701 controls each signal processing circuit via the control line 708 so as to cause each signal processing circuit to operate in parallel. First, the memory control circuit 703 is controlled to store the user data, which are input via the data line 709 from the input/output control circuit 90, to the memory 702. When a certain quantity of user data is stored in the memory 702, control is performed to cause the CRC calculation circuit 704 to attach CRC to the user data. Subsequently, control is performed so that a scramble circuit 705 scrambles the data with CRC by adding a pseudo random number data row, and an error correction symbolization circuit 706 performs error correction symbolization to add a parity data row. Finally, a pickup interface circuit 707 reads the data applied with the error correction symbolization from the memory 702 in the order of the arrangement of the two-dimensional data on the spatial light modulation device 312, and a marker serving as the reference during reproduction is added, and thereafter, the two-dimensional data are transferred to the spatial light modulation device 312 in the pickup 11.
When the light detection device 325 in the pickup 11 detects image data, the controller 89 commands the signal processing circuit 85 to perform reproducing processing to reproduce data for one page which are input from the pickup 11. The processing command from the controller 89 passes through the control line 811, and is notified to the sub-controller 801 in the signal processing circuit 85. Upon receiving this notification, the sub-controller 801 controls each signal processing circuit via the control line 811 to cause the signal processing circuits to operate in parallel. First, the memory control circuit 803 is controlled to store the image data, which are input via the data line 812 from the pickup 11 by way of the pickup interface circuit 810, to the memory 802. When a certain quantity of data are stored in the memory 802, control is performed to cause an image position detection circuit 809 to detect a marker from the image data stored in the memory 802 to extract an effective data range. Subsequently, control is performed to cause an image distortion correction circuit 808 to correct distortion such as inclination, magnification rate, and distortion of the image using the detected marker, and the image data are converted into an expected size of two-dimensional data. Then, control is performed to cause a binarization circuit 807 to perform binarization to determine “0” and “1” in each bit data of multiple bits constituting the two-dimensional data of which size has been converted, and the data are stored in the order of output of the reproduction data to the memory 802. Subsequently, the error correction circuit 806 corrects errors included in each data row, and the scramble cancellation circuit 805 descrambles the data with the pseudo random number data row, and thereafter, the CRC calculation circuit 804 confirms that no error is included in the user data on the memory 802. Thereafter, the user data are transferred to the input/output control circuit 90 from the memory 802.
FIGS. 10(1) and 10(2) are figures illustrating a layer structure of an optical information recording medium having a reflection layer. FIG. 10(1) illustrates the state in which information is recorded to the optical information recording medium. FIG. 10(2) illustrates the state in which information is reproduced from the optical information recording medium.
The optical information recording medium 1 has a transparent cover layer 1000, a recording layer 1002, a light absorption/light passing layer 1006, a light reflection layer 1010, and a third transparent protective layer 1012, which are arranged from the light pickup 11. An interference pattern of the reference light 10A and the signal light 10B is recorded to the recording layer 1002.
The light absorption/light passing layer 1006 changes the physical property so as to absorb the reference light 10A and the signal light 10B during information recording and pass the reference light during information reproducing. For example, a voltage is applied to the light recording medium 1, whereby the colored and decolored state of the light absorption/light passing layer 1006 changes, and more specifically, during information recording, the light absorption/light passing layer 1006 is in the colored state, so that the reference light 10A and the signal light 10B having passed the recording layer 1002 are absorbed, and during information reproducing, the light absorption/light passing layer 1006 is in the decolored state, so that the reference light is allowed to pass therethrough (T. Ando et. al.: Technical Digest ISOM (2006), Th-PP-10). The reference light 10A having passed through the light absorption/light passing layer 1006 is reflected by the light reflection layer 1010 to become the reproduction reference light 10C.
WO3 serving as electrochromic (EC) material described in A. Hirotsune et. al.: Technical Digest ISOM (2006), Mo-B-04 may be used as the light absorption/light passing layer 1006.
The colored and decolored states are caused in a reversible manner by applying a voltage to the material, and during information recording, the light is absorbed in the colored state, and during information reproducing, the light is passed in the decolored state.
With the configuration in
Here, the inventors will explain, in details, a technique for adjusting the recording condition in a holographic memory.
a) is a schematic diagram illustrating an example of relationship of a reproduction light intensity and a reference light angle in the same book in the optical information recording/reproduction device.
SSR=Signal/Scatter (Expression 1)
It should be noted that the ratio of the values obtained by subtracting the camera output value when the light is not input from the Signal value and the Scatter value may be defined as the SSR. In this case, where the camera output value when the light is not input is denoted as I, the SSR can be expressed by the following expression (Expression 2).
SSR=(Signal−I)/(Scatter−I) (Expression 2)
The target Signal explained above is, for example, a Signal value such that all the pages attain the target SSR under the calculated Scatter values, and is expressed by the following expression (Expression 3) or (Expression 4). The Scatter value is a different value for each page, and accordingly, the target Signal value is a different value for each page.
target Signal=target SSR×Scatter (Expression 3)
target Signal=target SSR×(Scatter−I)+I (Expression 4)
In the calculation of the Signal and the Scatter, all the pages may be scanned as shown in
M/#=Ση (Expression 5)
The saved location of the exposure light energy density used during recording after the adjustment may be provided on an optical information recording medium separately from the adjustment area. The adjustment may be done on every occasion before recording, or only when a disk is replaced, or every time a predetermined recording time or the number of times of recording is attained, or only when the change in the environment such as the temperature and the humidity is detected and a great change occurs. Information about the recording condition such as the signal-to-scatter ratio and the exposure light energy density suitable for recording the optical information recording medium, the exposure light power density, the exposure light time, the time for waiting the dark reaction, the exposure light energy density for pre-cure, the exposure light energy density for post-cure, and the like may be saved, before shipment, in an optical information recording medium or a cartridge storing an optical information recording medium. For example, the recording reference light angle of each page and the exposure light time for the laser power density are saved in an optical information recording medium and the like in the configuration as shown in
Information about the recording condition may be saved in an optical information recording/reproduction device or a device for controlling an optical information recording/reproduction device. The optical information recording/reproduction device may record user data by using information about the recording condition, or may first refer to the information about the recording condition, and adjust the recording condition according to the above method, and thereafter, record the user data.
In the method according to the present embodiment, the recording condition is adjusted under the same condition as the condition when the user data are actually recorded or a condition similar thereto, and therefore, there is an advantage in that more suitable recording condition can be calculated.
The SSRs of all the pages are equal to or more than the target value, so that the high quality hologram can be recorded, and a high quality signal can be obtained during reproduction.
The variation of SSRs between different pages is within the predetermined range (desirably, the SSRs of the pages are substantially the same), so that the limited M/# of the optical information recording medium can be effectively distributed to the pages, and not only the number of multiplex but also the recording capacity can be improved. The SNRs between the pages are equal, and therefore, for example, the servo signal can be generated by using the difference of the SNRs between pages, and in addition, the reference light angle compensation accuracy and the like during reproduction can be improved.
In the explanation below, explanation about the same contents as the present embodiment is omitted.
A second embodiment of the present invention will be explained with reference to
For example, the exposure light energy densities of multiple optical information recording media having different M/# and sensitivities are generated in advance according to the method using SSR as the index shown in the first embodiment, and the calculation expression of the exposure light energy density determined from M/# and the sensitivity is calculated using, for example, an approximation method and the like, and the calculation expression is saved in the optical information recording/reproduction device. Alternatively, an expression theoretically derived may be saved as the calculation expression in the information recording/reproduction device. The sensitivity is defined by the following expression, and is obtained by dividing M/# multiplied by 0.8 by the energy density required for recording consuming M/# multiplied by 0.8.
sensitivity=0.8×M/#/(energy density required for recording of M/# multiplied by 0.8) (Expression 6)
The method according to the present embodiment can be realized with a smaller circuit scale or eliminates the necessity to perform repetition processing as compared with the method according to the first embodiment, and there is an advantage in that the adjustment time is shorter.
Even with the same type of optical information recording media, M/# and/or the sensitivity are slightly different depending on each optical information recording medium, and therefore, before recording, M/# and/or the sensitivity are measured, and the exposure light energy is determined in accordance with the measurement result, so that there is an advantage in that M/# and/or the sensitivity for each optical information recording medium can cope with the difference.
In the explanation below, explanation about the same contents as the present embodiment is omitted.
In the present embodiment, the configuration for determining the exposure light energy density on the basis of M/# and the sensitivity has been explained. The present invention is not limited thereto. As necessary, the exposure light energy density may be determined on the basis of any one of M/# and the sensitivity.
A third embodiment according to the present invention will be explained with reference to
In the present embodiment, for example, when there is a change in the environment such as the temperature, the humidity, and the laser coherency during recording, the basic scheduling waveform generated in the method according to the second embodiment is finely corrected by multiplying it by a constant as shown in
E
n
′=E
n
×A′/A (Expression 7)
The SSR is used as an index, for example. Alternatively, it is not limited to the SSR. For example, the SNR (signal-to-noise ratio), the reproduction light intensity, the reproduction light intensity to the ½-th power, the diffraction efficiency, or the diffraction efficiency to the ½-th power may be used. In this case, there are multiple definition expressions of the SNR, and, for example, it can be expressed by the following expressions. In this case, μON is an average value of ON pixels, μOFF is an average value of OFF pixels, σON is a standard deviation of ON pixels, and σOFF is a standard deviation of OFF pixels. In order to express in decibel, 20 log of the values of the following expressions may be calculated.
SNR=(μON+μOFF)/(σON+σOFF) (Expression 8)
SNR=(μON+μOFF)/(σON2+σOFF2)0.5 (Expression 9)
In the method according to the present embodiment, even if there are less recording pages during the adjustment, the exposure light energy density can be calculated by using the linear interpolation or the approximated curve, and therefore, there is an advantage the recording condition can be adjusted in a shorter time or less processing.
In the explanation below, explanation about the same contents as the present embodiment is omitted.
A fourth embodiment according to the present invention will be explained with reference to
In this case, when the scheduling waveform is changed, for example, the basic scheduling waveform is multiplied by an adjustment coefficient a. Thereafter, the recording/reproduction is performed using the scheduling waveform multiplied by the adjustment coefficient, and the reproduction quality is measured. At this occasion, recording is performed with multiple conditions while the adjustment coefficient a is changed, and an adjustment coefficient a′ for higher quality reproduction is derived, and the adjusted scheduling waveform is generated as a basic scheduling waveform multiplied by a′. In this case, the basic scheduling waveform is saved in, for example, an optical information recording medium, a cartridge storing the optical information recording medium, an optical information recording/reproduction device, or a device for controlling an optical information recording/reproduction device, and the basic scheduling waveform is read and used before the adjustment.
In the method according to the present embodiment, the exposure light energy density is adjusted by recording/reproducing multiple books while changing the numerical value by which the basic scheduling waveform is multiplied, and therefore, as compared with the method according to the third embodiment for performing adjustment in a simplified manner by changing the exposure light energy density for each page, there is an advantage in that the adjustment can be done with a higher precision recording condition.
The present invention is not limited to above embodiments, and various modifications are included. For example, the above embodiments are provided to explain the present invention in details in an easy to understand manner, and the present invention is not limited to those having all the constituent elements explained. Some of the constituent elements of a certain embodiment may be replaced with constituent elements of another embodiment, and the constituent elements of a certain embodiment may be added to constituent elements of another embodiment. Some of the constituent elements of each embodiment may be added, deleted, or replaced with constituent elements of another embodiment.
Some or all of the above configurations, functions, processing units, processing means, and the like may be realized with hardware by designing an integrated circuit, for example. The above configuration, functions, and the like may be realized with software by causing a processor to interpret and execute a program achieving the functions. Information such as the programs, tables, files for achieving the functions can be placed in a recording device such as a memory, a hard disk, an SSD (Solid State Drive) and a recording medium such as an IC card, an SD card, and a DVD.
The control lines and information lines which are considered to be necessary for explanation are shown. Not all the control lines and information lines in a product may be shown. In reality, substantially all the constituent elements may be considered to be connected with each other.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2012/003352 | 5/23/2012 | WO | 00 | 11/12/2014 |
