The present invention relates to a multilayer optical disc having information layers conforming to a plurality of different optical disc standards and an optical disc device for recording or reproducing information on the optical disc.
Optical discs are a subject of research in the information recording field. They have a wide range of applications, from industrial use to consumer use, because they enable non-contact recording and reproduction, because they can accommodate large files at low cost, and because reproduction-only, writable, or rewritable media can be selected according to the application.
The capacity of optical discs has been increased by reducing the size of the information stored on the tracks, by using laser beams having shorter wavelengths as light sources for recording and reproducing, by using objective lenses with higher numerical apertures, and by reducing the size of the focused light spot on the focal plane.
For example, in a CD (compact disc), the thickness of the disc substrate used as a light transmitting layer is about 1.2 mm, the wavelength of the laser beam is about 780 nm, the numerical aperture (NA) of the objective lens is 0.45, and the disc capacity is 650 MB. In a DVD (digital versatile disc), the thickness of the disc substrate used as a light transmitting layer is about 0.6 mm, the wavelength of the laser beam is about 650 nm, the numerical aperture of the object lens is 0.6, and the disc capacity is 4.7 GB. For a DVD, two disc substrates having thicknesses of about 0.6 mm each are laminated together, to obtain a disc having a thickness of about 1.2 mm.
A BD (Blu-ray disc) disc having a still higher density uses an optical disc having a protection layer as thin as 0.1 mm as the light transmitting layer on the optical recording layer. With a laser beam wavelength of about 405 nm and a numerical aperture of 0.85, capacities in excess of 23 GB are obtained.
Thus, as optical disc capacities have increased, various optical disc standards have been established, including CD, DVD, and BD. Optical disc recording and reproducing devices are generally compatible with a plurality of different optical disc standards.
For example, some DVD recording and reproducing devices can record and reproduce information not only on a DVD but also on a CD. Some BD recording and reproducing devices can record and reproduce information on BDs, DVDs, and CDs. These compatible recording and reproducing devices are extremely convenient because they allow the user to record and reproduce information on optical discs in the user's possession that conform to old standards, and they have played an important role in smoothing the introduction of new standards.
Although discs have been manufactured according to each of the different standards, to increase the user's convenience, a multilayer optical disc having information layers conforming to a plurality of different optical disc standards has been developed (for example, patent document 1).
Patent document 1: Japanese Unexamined Patent Application Publication No. 2004-95005
A problem with such optical discs as the above is that when one information layer is being accessed, it is not known whether another information layer is present or not, so if the need to reproduce or record information on another information layer suddenly arises, it takes time to access the other designated information layer.
Another problem with optical discs such as the above is that the type of one information layer is not recorded on another layer, so when an optical disc device conforming to a plurality of different optical disc standards reads or writes information, every time the device accesses a different information layer, it must read the type of the layer to select a method of generating a tracking error signal adapted to the type; consequently, access takes time.
The purpose of the present invention is to shorten the access time in a multilayer optical disc having information layers conforming to a plurality of different optical disc standards.
In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, the present invention is an optical disc in which an information layer of highest recording density has a management area in which information indicating the types of other information layers is recorded, the types including at least a reproduction-only type.
In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, the present invention is also an optical disc in which an information layer of highest recording density has a management area in which information indicating presence or absence of other information layers is recorded.
In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, the present invention enables the access time to be shortened.
1 optical disc, 2a blue-violet semiconductor laser light source, 2b red semiconductor laser light source, 2c infrared semiconductor laser light source, 3a beam from blue-violet semiconductor laser light source, 3b beam from red semiconductor laser light source, 3c beam from infrared semiconductor laser light source, 4a, 4b, 4c collimating lens, 5a, 5b, 5c prism, 6 objective lens, 7a focused spot from blue-violet semiconductor laser light source, 7b focused spot from red semiconductor laser light source, 7c focused spot from infrared semiconductor laser light source, 8 sensor lens, 9 photodetector, 10 signal processing means, 11 image processing means, 12 optical disc device, 13 host device, 14, 14a management area, 15, 15a user data area, 16, information field, 17 land, 18 groove, 19 recording mark, 20 pit, 21 indicator area, 22 type area
The first embodiment of the invention will now be described with reference to the attached drawings. The optical disc 1 in the first embodiment is provided with information layers L1, L2, and L3 for a plurality of differing optical disc standards. Information layers L1, L2, and L3 are disposed at distances of 0.1 mm, 0.6 mm, and 1.2 mm from the surface, in this order. These information layers L1, L2, and L3 satisfy the BD, DVD, and CD optical disc standards, in this order, information layer L1 being the layer with the highest recording density, information layer L3 being the layer with the lowest recording density. In the following description, these layers are a reproduction-only layer, a writable layer, and a reproduction-only layer, respectively.
In the state in
The beam 3a reflected from information layer L1 returns to the objective lens 6, then passes through prisms 5a, 5b, 5c and is directed by a sensor lens 8 onto a photodetector 9.
The photodetector 9 converts the received light beam into electrical signals for output to a signal processing means 10. The signal processing means 10 controls the amount of light emitted by light source 2a, generates a tracking error signal indicating the relative positional discrepancy between the focused spot and the tracks on the information layer, and after signal processing, outputs information to an image processing means 11. The image processing means 11 performs image processing and output.
The above elements from the laser light source 2a to the image processing means 11 constitute an optical disc device 12. The optical disc device 12 records and reproduces information on the optical disc 1 according to commands from a host device 13. The host device 13 is a PC (personal computer) that instructs the optical disc device 12 to record and reproduce information. Alternatively, the host device 13 may be an audiovisual reproduction device that decodes information read out from the optical disc device 12 and outputs images and/or sounds, and/or an audiovisual recording device that encodes image and/or sound information input from an external device and instructs the optical disc device 12 to record the information.
In the state in
The beam 3b now passes through information layer L1. The material and structure of information layer L1 are selected so as to avoid interference with access to information layer L2, taking physical properties such as transmittance and reflectance of a light beam having a wavelength of about 650 nm into consideration.
The beam 3b reflected from information layer L2 returns to the objective lens 6, then passes through prisms 5a, 5b, 5c and is directed by the sensor lens 8 onto the photodetector 9. The signal processing means 10 and image processing means 11 operate as above; descriptions will be omitted. In
In the state in
The beam 3c now passes through information layers L1 and L2. The materials and structure of information layers L1 and L2 are selected so as to avoid interference with access to information layer L3, taking physical properties such as transmittance and reflectance of a light beam having a wavelength of about 780 nm into consideration.
The beam 3b reflected from information layer L2 returns to the objective lens 6, then passes through prisms 5a, 5b, 5c and is directed by the sensor lens 8 onto the photodetector 9. The signal processing means 10 and image processing means 11 operate as above; descriptions will be omitted. In
The management area 14 disposed in information layer L1 in
In
In
Similarly, in response to a command from the host device 13 to reproduce information from information layer L3 (ST10), the optical disc device 12 follows the sequence by reading the type of information layer L3 retained in the signal processing means 10 as above (ST11). As information layer L3 is a reproduction-only layer (TRUE in ST 12), the DPD method is selected, which is suitable for reproduction-only information layer L3, the laser power of the laser having a wavelength suitable for information layer L3 is set at the same time, a tracking error signal is generated (ST16), and information is reproduced from information layer L3 (ST17).
When the optical disc device 12 receives the information reproducing command from the host device 13, if the type of information layer L3 retained in the signal processing means 10 is neither the reproduction-only type nor the writable type (FALSE in ST12 and ST13), that is, if the type information is not recognizable by the optical disc device, a notification is returned to the host device 13 indicating that the information layer to be reproduced is not accessible (ST18), and the process ends (ST19). The optical disc device 12 returns to a standby mode to wait for the next command from the host device 13.
In
In this embodiment, in a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, information indicating the type of other information layers is recorded, so the optical disc device can easily identify the types of the other information layers, and access time to those layers can be shortened.
Furthermore, the information indicating the types of the other information layers is recorded in the management area of the information layer having the highest recording density. It can be anticipated that the information layer having the highest recording density will be accessed most frequently, so the optical disc device will be sure to read and retain the information.
When recording and reproducing information on an optical disc as above, before access, the optical disc device can set a suitable value for the laser power of the laser having a wavelength suitable for the layer to be accessed, based on the information indicating the type of the information layer. Also, the method of generating a tracking error indicating a relative positional discrepancy between the focused spot and the information written in tracks in a direction crossing the plurality of tracks can be determined in advance, so access time can be shortened.
The second embodiment is similar to the first embodiment in regard to
Referring to
In
When an optical disc is inserted into the optical disc device, the device reads the information in areas T2, T3, T4 of the indicator area 21 in the management area 14a on information layer L1 of the optical disc to obtain information indicating the presence or absence of information layers L2 and L3 and information layers conforming to other standards. When one of areas T2, T3, T4 indicates the presence of a corresponding information layer (bit value ‘1’), the optical disc device reads the corresponding one of areas U2, U3, U4 in the type area 22 in the management area 14a, obtains information indicating the type of information layer, and retains the obtained information in the signal processing means 10. Subsequent operations are similar to those shown in the flowchart in
The optical disc device can be configured to read only those of the areas U2, U3, U4 in the type area 22 corresponding to areas T2, T3, T4 indicating the presence of an information layer (bit value ‘1’). Alternatively, the optical disc device can be configured to read information in all areas U2, U3, U4 of the type area 22 regardless of whether the corresponding information layer is present or not.
When an information layer corresponding to area T4 is present, and the information layer conforms to an optical disc standard, other than the BD standard, that uses a blue-violet semiconductor laser having a wavelength of about 405 nm as a light source, the disc will have a plurality of information layers (two layers, information layer L1 and the information layer corresponding to area T4) using the shortest wavelength of approximately 405 nm; in this case, the indicator area 21 and type area 22 are provided at least in information layer L1. The indicator area 21 and type area 22 may be provided not just on information layer L1 but also on the information layer corresponding to area T4.
Alternatively, areas T4 and U4 may be left empty, with no particular information stored, reserved for use in case a new standard is developed in the future. The indicator area 21 and type area 22 then hold information for two types of information layers, these being information layers L2 and L3.
Alternatively, the two bits assigned to area U2 may classify the corresponding DVD layer according to its type of information track structure. The classification may be based on the periodic structure of the information tracks, e.g., on their wobble frequency. For example, when the layer is a reproduction-only type layer such as a DVD-ROM layer having only pre-pits with no wobble, the bit value may be ‘00’. For DVD-R and DVD-RW, which have wobble, the bit value may be ‘01’. For DVD+R and DVD+RW, which have wobble with higher wobble frequency than DVD-R and DVD-RW, the bit value may be ‘10’. For DVD-RAM in which the head is shifted in the radius direction on a land/groove single spiral structure with no wobble, the bit value may be ‘11’. The frequency structure of the information tracks in a DVD layer has the same format for each category, so the characteristics of the wobble signal detection circuit (a circuit such as a band-pass filter for detecting the frequency of the periodic structure) can be set prior to access to the DVD layer, the disc rotation can be rapidly brought to the target value, and the access time can therefore be shortened.
In this embodiment, in a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, information indicating the presence of other information layers is recorded, so the optical disc device can easily identify the presence or absence of other information layers, and access time can be shortened.
Furthermore, in the management region of the optical disc, a type area 22 which stores information indicating the types of information layers is provided in addition to the indicator area 21 which stores information indicating the presence or absence of other information layers, and the information in the indicator area 21 is related to the information in the type area 22 so that the information in the indicator area 21 and the information in the type area 22 have a hierarchical structure. Therefore, if another area is created in the user data area 15 in the future, or if another type of information layer is added, the hierarchical structure can be exploited to accommodate the expansion.
Furthermore, the information is recorded in the management area in an information layer having the highest recording density, which is expected to be the information layer most frequently accessed, ensuring that the optical disc device will read and retain the information.
When recording and reproducing information on an optical disc of this type, the optical disc device can set a suitable value for the laser power of a laser having a wavelength suitable for the layer to be accessed, based on information such as the above. The method of generating the tracking error signal indicating a relative positional discrepancy between the focused spot and the information written in the tracks in a direction crossing a plurality of tracks can be determined in advance, so the access time can be shortened.
In the third embodiment, the optical disc 1 has at most two types of information layers, including the type of the L1 layer. The third embodiment is similar to the second embodiment in regard to
In
When an information layer other than information layer L1 is present, area V1 in the type area 22 indicates the type of this information layer. The type area 22 includes only the two bits of information in area V1. The values of these bits are ‘00’ when the information layer is of the reproduction-only type, ‘01’ when it is of the writable type, and ‘10’ when it is of the rewritable type. The writable type includes DVD-R, DVD+R, and their dual-layer standards. The rewritable type includes dual-layer DVD-RW and DVD+RW and DVD-RAM.
For example when information layer L1 is a writable layer or pair of layers, information layers L2 and L3 are reproduction-only layers, and no other layers are present (T2=1, T3=1, T4=0), the bit values in area V1 will be ‘00’.
Thus, in the optical disc 1, when at least one of areas T2, T3, T4 in the indicator area 21 has a bit value of ‘1’ and the corresponding information layers are of only one type, or when only one of areas T2, T3, T4 has a bit value of ‘1’, the type area 22 can have only two bits, producing a saving of information bits as compared with the second embodiment above. In particular, there is an anticipated market demand for optical discs having only one of information layers L2 and L3 and using it as a reproduction-only layer, so if only optical discs having information layer L2 or L3 and using it as a reproduction-only layer are manufactured and sold, the two bits of area V1 will suffice for the type area 22.
Alternatively, as shown in the second embodiment, the classification in area V1 may be based on the type of information track structure, such as the presence or absence of wobble.
Although the area V1 of the type area 22 was shown as having two bits of information in this embodiment, it may have only one bit of information, saving one further information bit. In this case, the reproduction-only type may be indicated by ‘0’ and other types, that is, the writable type and rewritable type, may be indicated by Alternatively, the classification may be based on the type of information track structure: for example, ‘0’ when there is no wobble and ‘1’ when wobble is present.
Furthermore, when the area V1 storing information indicating the type of information layer has only one bit and area T4 in the indicator area 21 in
Other effects are similar to those shown in first and second embodiments.
It is possible to use the type area 22 of the second and third embodiments as a reserved area having a value of ‘00’ or ‘0’ with no information assigned, in expectation that effective use of this area can be made in the future. Also, as described in the third embodiment, if only optical discs having information layers L2 and L3 of the reproduction-only type are manufactured and sold, there is no particular need to assign information indicating the type of the information layer to the type area 22.
However, if the market changes in the future and not only optical discs having information layers L2 and L3 of the reproduction-only type but various other types of hybrid optical discs are manufactured and sold, it will be necessary to use the bit or bits in the type area 22 to indicate the type of information layer. In order to ensure compatibility with optical discs having information layers L2 and L3 of the reproduction-only type, the bit values ‘00’ or ‘0’ should be assigned to indicate the reproduction-only type, which is the type most frequently used. If these bits are used for indicating some completely different property, the value ‘00’ or ‘0’ should be protected in some way, such as being used only as a reserved value.
This embodiment provides only the information stored in the indicator area to indicate the presence or absence of other information layers, but since this information enables the optical disc device to identify the presence or absence of other information layers, it contributes to the shortening of the access time.
Number | Date | Country | Kind |
---|---|---|---|
2005-039026 | Feb 2005 | JP | national |
2005-043131 | Feb 2005 | JP | national |
This application is a Divisional of application Ser. No. 14/062,152 filed Oct. 24, 2013, which is a Divisional of application Ser. No. 13/551,113, filed Jul. 17, 2012, which is a Divisional of application Ser. No. 11/822,249, filed Jul. 3, 2007 (now U.S. Pat. No. 8,248,907, issued Aug. 21, 2012), which is a Divisional of application Ser. No. 11/579,832, filed on Nov. 7, 2006 (now U.S. Pat. No. 8,036,086, issued Oct. 11, 2011), for which priority is claimed under 35 U.S.C. §120. application Ser. No. 11/579,832 is the national phase of PCT International Application No. PCT/JP2005/015160 filed on Aug. 19, 2005 under 35 U.S.C. §371. The entire contents of each of the above-identified applications are hereby incorporated by reference.
Number | Name | Date | Kind |
---|---|---|---|
5732065 | Braat et al. | Mar 1998 | A |
5737287 | Lee | Apr 1998 | A |
5793720 | Nishikata | Aug 1998 | A |
5903531 | Satoh et al. | May 1999 | A |
5959948 | Oshima | Sep 1999 | A |
6320840 | Oh et al. | Nov 2001 | B1 |
6498775 | Fan et al. | Dec 2002 | B1 |
6538963 | Fukada | Mar 2003 | B1 |
6720056 | Maeda et al. | Apr 2004 | B2 |
7151729 | Park et al. | Dec 2006 | B1 |
7286153 | Sugiyama et al. | Oct 2007 | B1 |
7623428 | Suh | Nov 2009 | B2 |
7773485 | Nakahara et al. | Aug 2010 | B2 |
7830767 | Suh | Nov 2010 | B2 |
8036086 | Nakahara et al. | Oct 2011 | B2 |
8045441 | Nakahara et al. | Oct 2011 | B2 |
8213290 | Nakahara et al. | Jul 2012 | B2 |
8248907 | Nakahara et al. | Aug 2012 | B2 |
8254240 | Nakahara et al. | Aug 2012 | B2 |
20010038578 | Oshima | Nov 2001 | A1 |
20020101811 | Mons et al. | Aug 2002 | A1 |
20030227858 | Komma | Dec 2003 | A1 |
20040076101 | Suh et al. | Apr 2004 | A1 |
20040233809 | Suh et al. | Nov 2004 | A1 |
20050025013 | Yamamoto | Feb 2005 | A1 |
20050036426 | Suh | Feb 2005 | A1 |
20050036427 | Suh | Feb 2005 | A1 |
20050188394 | Choi | Aug 2005 | A1 |
20050219991 | Van Den Oetelaar et al. | Oct 2005 | A1 |
20050265151 | Kimura et al. | Dec 2005 | A1 |
20050276199 | Sugai | Dec 2005 | A1 |
20060136958 | LeBlanc et al. | Jun 2006 | A1 |
20070002699 | Suh | Jan 2007 | A1 |
20070253301 | Nakahara et al. | Nov 2007 | A1 |
20070253302 | Nakahara et al. | Nov 2007 | A1 |
20070263499 | Nakahara et al. | Nov 2007 | A1 |
20080056096 | Nakahara et al. | Mar 2008 | A1 |
20080107010 | Town | May 2008 | A1 |
20080279085 | Yashima et al. | Nov 2008 | A1 |
20090034387 | Hamasaka | Feb 2009 | A1 |
Number | Date | Country |
---|---|---|
1135634 | Nov 1996 | CN |
1144011 | Feb 1997 | CN |
1165575 | Nov 1997 | CN |
1175760 | Mar 1998 | CN |
1330368 | Jan 2002 | CN |
1332453 | Jan 2002 | CN |
1155001 | Jun 2004 | CN |
0 833 311 | Apr 1998 | EP |
1 065 665 | Jan 2001 | EP |
1 111 604 | Jun 2001 | EP |
1 492 098 | Dec 2004 | EP |
2 439 224 | Dec 2007 | GB |
9-509776 | Sep 1997 | JP |
9-274765 | Oct 1997 | JP |
11-66576 | Mar 1999 | JP |
11-086338 | Mar 1999 | JP |
11-232700 | Aug 1999 | JP |
11-238362 | Aug 1999 | JP |
2003-308631 | Oct 2003 | JP |
2004-95005 | Mar 2004 | JP |
2004-199757 | Jul 2004 | JP |
2004-206849 | Jul 2004 | JP |
2005-38584 | Feb 2005 | JP |
2006-172574 | Jun 2006 | JP |
2005-020715 | Aug 2006 | JP |
2008-287861 | Nov 2008 | JP |
1020040079944 | Sep 2004 | KR |
WO 9619807 | Jun 1996 | WO |
WO 9709716 | Mar 1997 | WO |
WO 0101408 | Jan 2001 | WO |
WO 03063144 | Jul 2003 | WO |
WO 03098628 | Nov 2003 | WO |
WO 2006080350 | Aug 2006 | WO |
Number | Date | Country | |
---|---|---|---|
20140050073 A1 | Feb 2014 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 14062152 | Oct 2013 | US |
Child | 14063826 | US | |
Parent | 13551113 | Jul 2012 | US |
Child | 14062152 | US | |
Parent | 11822249 | Jul 2007 | US |
Child | 13551113 | US | |
Parent | 11579832 | US | |
Child | 11822249 | US |