JPWO2015163271A1 - optical disk - Google Patents

Abstract

An optical disc capable of easily acquiring relative position information of a recording layer is provided. An optical disc according to an embodiment of the present invention includes at least two recording layers for recording information on a spiral information track formed from one of an inner peripheral side and an outer peripheral side to the other. The recording layer is located on the inner circumference side area located on the inner circumference side, located on the outer circumference side with respect to the inner circumference side area, and positioned on the outer circumference side with respect to the data area and the data area for recording content information. And an outer peripheral side region. At least one of the inner and outer peripheral areas of the plurality of recording layers has an information track adjacent to the information track at a different period along the information track for each recording layer and within the same recording layer. There is provided a recording layer discriminating area in which recording layer discriminating information is formed so that the phases coincide with each other.

Description

  The present invention relates to an optical disc having a plurality of recording layers.

  Increasing the density of optical disks such as CDs and DVDs. In recent years, with the development of a blue-violet laser, a BD (Blu-ray (registered trademark) Disc) having a higher recording density than a DVD has been realized. By providing a plurality of recording layers on such a BD, the capacity of the optical disk can be further increased.

  As a technique for discriminating which recording layer is currently being recorded or reproduced in an optical disc forming a plurality of recording layers, those disclosed in Patent Document 1 and Patent Document 2 are known. .

JP-A-3-219440 Special table 2007-500410 gazette

  In the technique disclosed in Patent Document 1, an identification unit in which an address is recorded is formed on each recording layer of an optical disc, and the recording layer is identified by this address. The technique disclosed in Patent Document 2 records identification data for identifying a recording layer in a PIC band (Permanent Information & Control Zone) of a lead-in area of an optical disc.

  However, all these prior arts identify the recording layer in an on-track state, and there is a problem that it takes time to identify the recording layer. The present invention has been made in view of such a problem, and an object thereof is to provide an optical disc capable of easily discriminating each recording layer.

  An optical disc according to an embodiment of the present invention includes at least two recording layers for recording information on a spiral information track formed from one of the inner peripheral side and the outer peripheral side to the other. The recording layer is located on the inner circumference side area located on the inner circumference side, located on the outer circumference side with respect to the inner circumference side area, and positioned on the outer circumference side with respect to the data area and the data area for recording content information. And an outer peripheral side region. At least one of the inner and outer peripheral areas of the plurality of recording layers has an information track adjacent to the information track at a different period along the information track for each recording layer and within the same recording layer. There is provided a recording layer discriminating area in which recording layer discriminating information is formed so that the phases coincide with each other.

  Here, in the optical disc according to the above-described embodiment, the information track is formed such that the information tracks have different periods along the information track for each recording layer, and the phases of adjacent information tracks are the same in the same recording layer. A recording layer discrimination area in which recording layer discrimination information is recorded is provided. Therefore, if the focus control is performed, the periodic signal set for the recording layer can be detected even when the tracking control is not performed. Therefore, according to the optical disc according to such an embodiment, it is possible to provide an optical disc capable of quickly and easily discriminating the recording layer without the tracking.

  The recording layer discrimination area may be provided outside the area that requires tracking control. Furthermore, the recording layer discrimination area may be provided on the outer peripheral side of a BCA (Burst Cutting Area).

  Furthermore, the inner peripheral area of the predetermined recording layer has a BCA (Burst Cutting Area) and a first protection area provided on the outer peripheral side of the BCA, and the outer peripheral area of the other recording layers is The recording layer discriminating area may be from a radial position corresponding to the inner peripheral edge or outer peripheral edge of the BCA to a radial position corresponding to the inner peripheral edge of the first protective area. It may be provided in at least one of the region and the region on the outer peripheral side with respect to the radial position corresponding to the outer peripheral end of the lead-out region.

  The recording layer discrimination information may include a plurality of pits formed in the information track, or may include a wobble groove formed in the information track.

  According to the present invention, it is possible to provide an optical disc that can easily acquire relative position information of a recording layer.

1 is a schematic perspective view showing an example of an optical disc 1 according to a first embodiment of the present invention. It is a figure which shows the layout of the recording information of the recording layer L0 in an AA 'cross section. It is a figure which shows the layout of the recording information of the recording layer L1 in an AA 'cross section. It is a figure which shows the layout of the recording information of the recording layer L2 in an AA 'cross section. 3 is a schematic enlarged perspective view of an inner circumference L0 discrimination region 11. FIG. FIG. 6 is a schematic plan view for explaining the configuration of information tracks in an inner circumference L0 discrimination area 11; FIG. 6 is a schematic plan view for explaining the configuration of information tracks in an inner circumference L1 discrimination region 12; FIG. 5 is a schematic plan view for explaining the configuration of information tracks in an inner circumferential side L2 discrimination region 13; It is a rough expansion perspective view of the inner peripheral L0 discrimination | determination area | region 11-2 which concerns on the 2nd Embodiment of this invention. It is a schematic plan view for demonstrating the structure of the information track | truck in the inner peripheral side L0 discrimination | determination area | region 11-2 based on the embodiment. It is a schematic top view for demonstrating the structure of the information track | truck in the inner peripheral side L1 discrimination | determination area | region 12-2 which concerns on the embodiment. It is a schematic plan view for demonstrating the structure of the information track in the inner peripheral side L2 discrimination | determination area | region 13-2 which concerns on the embodiment. It is a schematic plan view for demonstrating the structure of the information track | truck in the inner peripheral side L0 discrimination | determination area | region 11-3 based on the 3rd Embodiment of this invention. It is a schematic top view for demonstrating the structure of the information track | truck in the inner peripheral side L1 discrimination | determination area | region 12-3 based on the embodiment. It is a schematic top view for demonstrating the structure of the information track | truck in the inner peripheral side L2 discrimination | determination area | region 13-3 based on the embodiment. It is a rough expansion perspective view for demonstrating the structure of the information track | truck in the inner peripheral side L0 discrimination | determination area | region 11-4 which concerns on other embodiment. It is a rough expansion perspective view for demonstrating the structure of the information track | truck in the inner peripheral side L0 discrimination | determination area | region 11-5 which concerns on other embodiment.

[Schematic Configuration of Optical Disc According to First Embodiment of the Present Invention]
FIG. 1 is a schematic perspective view showing an example of an optical disc 1 according to the first embodiment of the present invention. The optical disc 1 according to the present embodiment is a laminated type Blu-ray disc ROM or recording type disc in which three recording layers L0 to L2 are laminated. On the recording surface of the recording layers L0 to L2, an inner peripheral area 10 located in a predetermined area on the inner peripheral side, and a data area 20 that is positioned on the outer peripheral side with respect to the inner peripheral area 10 and that records content information. And an outer peripheral region 30 located on the outer peripheral side with respect to the data region 20 is provided.

  In the optical disc 1 according to the present embodiment, information is recorded or reproduced from the inner circumference side to the outer circumference side in the recording layer L0, and the subsequent information is recorded or reproduced from the outer circumference side to the inner circumference side in the recording layer L1. In the recording layer L2, further information is recorded or reproduced from the inner circumference side to the outer circumference side. Light for recording or reproduction is irradiated from the lower surface side of the optical disc 1 in FIG. 1, and the recording layer farthest from the light source is L0 and the closest recording layer is L2. The information of the recording layers L0 to L2 is recorded or reproduced by moving the focal position of the light source up and down.

  FIG. 2 is a diagram showing a layout of recording information in the AA ′ section of the recording layer L0. In the present embodiment, the inner circumferential area (Inner Zone) IZ (10) has a BCA (Burst Cutting Area) and an inner circumferential L0 determination area IL0 in order from the inner circumferential side. The BCA is an area for recording various information related to the optical disc 1 and is recorded on an optical disc production master or formed from the outside by a laser after the optical disc is produced.

  The inner peripheral area IZ is also used as a lead-in area, and includes a first protection area (Protection Zone) PrZ1, a PIC area (Permanent Information & Control Zone) PIC, a second protection area PrZ2, and information / Reserved area (INFO / Reserved) I / R.

  When the optical disc 1 is a recordable medium, the first protection area PrZ1 and the second protection area PrZ2 have a data write amount to the inner circumference L0 determination area IL0 (11) and the PIC area PIC that is greater than or equal to a predetermined amount, respectively. In such a case, data overwriting is prevented from being overwritten in the PIC area PIC and the information / reservation area I / R.

  On the other hand, when the optical disc 1 is a ROM type medium, the first protection area PrZ1 prevents the BCA laser writing from affecting the PIC area. The second protection area PrZ2 is provided between a wide pitch area and a normal pitch area, which will be described later, and prevents signal disturbance due to switching of the pitch interval on the information track from affecting the operation of the reading drive.

  The PIC area PIC records various information related to the optical disc 1 such as an address of content information and playback parameters of the optical disc 1. Similarly, the information / reservation area I / R also records various information regarding the optical disc 1.

  In the present embodiment, the data zone (Data Zone) DZ (20) is a region for recording content information such as movies, music, and programs.

  In the present embodiment, the outer peripheral area (Outer Zone) OZ (30) is an outer peripheral area of the data area DZ. The outer peripheral side region OZ has an outer peripheral side L0 determination region OL0 (31) provided in a region on the outer peripheral side with respect to a radial position corresponding to an outer peripheral end of a lead-out region 34 (FIG. 4) described later.

  FIG. 3 is a diagram showing a layout of recording information in the AA ′ section of the recording layer L1. When the optical disc 1 according to the present embodiment is a ROM type medium having three recording layers, the recording layer L1 is not provided with a BCA, lead-in area, and lead-out area (FIG. 4). In addition, an inner peripheral side L1 determination region IL1 is provided in a region from a radial position corresponding to the outer peripheral end of the BCA (FIG. 2) to a radial position approximately corresponding to the inner peripheral end of the first protection region PrZ1. An outer peripheral side L1 discrimination region OL1 is provided in a region on the outer peripheral side with respect to a radial position corresponding to the outer peripheral end of a lead-out region 34 (FIG. 4) described later.

  FIG. 4 is a diagram showing a layout of recording information in the AA ′ cross section of the recording layer L2. When the optical disc 1 according to the present embodiment is a ROM type medium having three recording layers, the recording layer L2 is not provided with a BCA and a lead-in area. In addition, an inner peripheral side L2 determination region IL2 is provided in a region from a radial position corresponding to the outer peripheral end of the BCA (FIG. 2) to a radial position approximately corresponding to the inner peripheral end of the first protection region PrZ1. .

  Further, in the outer peripheral side area OZ of the recording layer L2, a lead-out area 34 and an outer peripheral side L2 determination area OL2 are provided in order from the inner peripheral side.

  When the optical disc 1 according to the present embodiment is a recording-type disc, the information track is formed over almost the entire surface of the recording layer, but the first protective region PrZ1, the second protective region PrZ2, and the recording layer L1. In the inner peripheral side L1 discriminating region and the inner peripheral side L2 discriminating region in L2, no region is formed. Further, the distance in the radial direction of the information track and the distance in the rotation direction of the pits are relatively wide in the area (wide pitch area) provided on the inner circumference side than the second protection area PrZ2, and provided on the outer circumference side. The region (normal pitch region) is relatively narrow. Here, the interval between the pits in the wide pitch area may be adjusted so that it can be read using a laser beam such as a CD or a DVD.

  Hereinafter, the inner circumference L0 discrimination area IL0, the outer circumference L0 discrimination area OL0, the inner circumference L1 judgment area IL1, the outer circumference L1 judgment area OL1, the inner circumference L2 judgment area IL2, and the outer circumference L2 judgment area OL2 are combined. This is called a recording layer discrimination area. In each recording layer discriminating area, recording layer discriminating information for identifying which recording layer is accessed by the optical pickup is recorded.

[Configuration of recording layer discrimination area]
Next, the configuration of the recording layer discrimination area according to the present embodiment will be described. FIG. 5 is a schematic enlarged perspective view of the inner circumferential L0 discrimination region IL0 (11). The inner circumference L0 discrimination area IL0 (11) is provided with an information track that is formed in a spiral shape from the inner circumference side to the outer circumference side and includes a groove 111 that forms a convex portion and a land 112 that forms a concave portion. The information track according to the present embodiment has the groove 111 and the land 112. However, as will be described later, pits are formed on the groove 111 or the land 112, and information is obtained from the groove 111, the land 112, and the pit. It is also possible to form a track.

  The groove 111 travels along the direction of travel of the information track, and forms a wobble groove meandering periodically in the inner and outer circumferential directions of the optical disc 1. As shown in FIG. 5, the period in which the groove 111 meanders is a predetermined distance on the information track that is read while the optical disc 1 is rotated by a predetermined rotation angle θ. Here, the rotation angle θ is 360 ° by multiplying by an integer. Accordingly, the phases of the waves formed by the grooves 111 adjacent in the radial direction are equal. Further, since this period is defined by the rotation angle θ of the optical disc 1, the wavelength λ1 of the predetermined wave is shorter than the wavelength λ2 of the wave adjacent to the outer peripheral side with respect to this wave. However, the frequency of a signal read by CAV (Constant Angular Velocity) control is constant. In the present embodiment, the recording layer is determined based on the frequency of the constant wobble signal.

  Next, a specific configuration of each recording layer discrimination area will be described. 6 to 8 are schematic plan views for explaining the configuration of information tracks in the recording layer discrimination regions 11 to 13 on the inner circumference side.

  In the present embodiment, each layer is discriminated based on the wobble frequency of each layer discrimination region 11-13. In each layer discriminating area 11-13, at least one wobble in which a fundamental frequency (about 1 MHz) is obtained and a wobble in which an identification frequency for identifying each layer is obtained are formed in one circumference of the disk. For example, as shown in FIG. 6, in the inner circumference L0 discrimination region 11, the groove 111 meanders uniformly at a period of about 1 MHz (956.5522 kHz). Further, as shown in FIG. 7, in the inner circumferential side L1 discriminating region 12, a part of the groove 121 meanders with a period of about 1 MHz and the remaining part meanders with a period of about 500 kHz (478.261 kHz). Yes. Further, as shown in FIG. 8, in the inner circumferential side L2 discrimination region 13, a part of one circumference of the groove 131 meanders at a period of about 1 MHz, and the remaining part is about 250 kHz (239.130 kHz). Meanders in a cycle. The period in which the grooves 111, 121, and 131 meander constitute recording layer discrimination information. However, the fundamental frequency (about 1 MHz) described here may use another frequency. Further, different frequencies may be used for the identification frequency of each layer.

  When the inner circumference L0 discrimination area 11 is accessed, a uniform signal of about 1 MHz is read out by the pickup. On the other hand, when the inner circumference L1 discrimination area 12 is accessed, a signal of about 1 MHz and a signal of about 500 kHz are alternately read out by the pickup. Furthermore, when the inner circumference L2 discrimination area 13 is accessed, a signal of about 1 MHz and a signal of about 250 kHz are alternately read out by the pickup. By determining these signals, it is possible to determine the recording layer being accessed.

  The outer circumference L0 discrimination area OL0 has substantially the same configuration as the inner circumference L0 discrimination area IL0. Similarly, the outer circumference L1 discrimination area OL1 has the same configuration as the inner circumference L1 discrimination area IL1, and the outer circumference L2 discrimination area OL2 has substantially the same configuration as the inner circumference L2 discrimination area IL2. However, it is not necessary to arrange the meandering period of the groove with respect to the rotation angle between the inner recording layer discrimination area and the outer recording layer discrimination area. This is because no signal interference occurs between the recording layer discrimination areas IL0 to IL2 on the inner circumference side and the recording layer discrimination areas OL0 to OL2 on the outer circumference side.

[Effect of optical disc according to the present embodiment]
Next, effects of the optical disc 1 according to the present embodiment will be described. In the optical disc 1 according to the present embodiment, the recording layer formed on the information track so that the phase is different between adjacent information tracks in the same recording layer at different periods along the information track for each recording layer. A recording layer discrimination area in which discrimination information is recorded is provided. Therefore, even in the off-track state, it is possible to detect the wobble signal recorded in the recording layer discrimination region of the focused recording layer, and to read the recording layer discrimination information. Therefore, according to the optical disc according to such an embodiment, it is possible to provide an optical disc capable of quickly and easily discriminating the recording layer without the tracking.

  In the present embodiment, the recording layer discrimination area is provided outside the area requiring tracking control. Therefore, it is possible to read out the PIC area by starting tracking control after reading out the recording layer discrimination area while performing focusing and discriminating the recording layer. For this reason, the recording layer can be quickly identified. In addition, information such as the recording layer, the total number of layers, the recording position, and the recording end position can be stored by using a modulation signal using a wobble signal as a carrier, regardless of the pits described above.

[Optical Disc According to Second Embodiment of the Present Invention]
Next, an optical disc according to the second embodiment of the present invention will be described. The optical disc according to the present embodiment is basically configured similarly to the optical disc according to the first embodiment, but the configuration of the recording layer discrimination area is different.

  FIG. 9 is a schematic enlarged perspective view of the inner circumferential L0 discrimination region 11-2 according to the present embodiment. The information track in the inner circumference L0 discrimination area 11-2 does not have grooves and lands but has pits 113-2.

  The pits 113-2 are formed at predetermined intervals along the traveling direction of the information track. As shown in FIG. 9, the period in which the pits 113-2 are formed is a predetermined distance on the information track that is read while the optical disc 1 is rotated by a predetermined rotation angle θ. Here, the rotation angle θ is 360 ° by multiplying by an integer. Therefore, in the information track adjacent in the radial direction, the period in which the pits 113-2 are formed is equal. Further, since this period is defined by the rotation angle θ of the optical disc 1, the wavelength λ1 of the predetermined wave is shorter than the wavelength λ2 of the wave adjacent to the outer peripheral side with respect to this wave. However, the frequency of the signal read by CAV control is constant. In the present embodiment, the recording layer is discriminated based on the frequency of this constant pit signal.

  FIGS. 10 to 12 illustrate the configuration of information tracks in the inner circumference L0 discrimination area 11-2, the inner circumference L1 discrimination area 12-2, and the inner circumference L2 discrimination area 13-2 according to the present embodiment, respectively. FIG. As shown in the figure, in the present embodiment, the information tracks each including the pit 113-2, the pit 123-2, or the pit 133-2 are not formed in a wave shape.

  In the present embodiment, each layer is discriminated based on the interval at which the pits in each layer discrimination region 11-2 to 13-2 are formed. In each layer discriminating area 11 to 13-2, at least one place in the circumference of the disk, the pits arranged at intervals such that the fundamental frequency is obtained, and the intervals at which the identification frequency for identifying each layer is obtained. A pit arranged in the above is formed. For example, as shown in FIG. 10, in the inner circumference L0 discrimination region 11-2, pits 113-2 having a length of 4T are uniformly formed with a period of about 8T. Further, as shown in FIG. 11, in the inner circumferential side L1 discriminating region 12-2, some pits 123-2 having a length of 4T are formed with a period of 8T, and the remaining pits having a length of 6T are formed. The pits 123-2 are formed with a cycle of 12T. Furthermore, as shown in FIG. 12, in the inner circumferential side L2 discrimination region 13-2, some pits 133-2 having a length of 4T are formed with a period of 8T, and the remaining pits having a length of 8T are formed. The pits 133-2 are formed with a period of 16T. The pits 113-2, 123-2 and 133-2 constitute recording layer discrimination information. However, another frequency may be used as the fundamental frequency described here. Further, different frequencies may be used for the identification frequency of each layer.

  When the inner circumference L0 discrimination area 11-2 is accessed, a 4T uniform signal is read out by the pickup. On the other hand, when the inner circumference L1 discrimination area 12-2 is accessed, the 4T signal and the 6T signal are alternately read by the pickup. Further, when the inner circumferential side L2 discrimination area 13-2 is accessed, the 4T signal and the 8T signal are alternately read by the pickup. By determining these signals, it is possible to determine the recording layer being accessed.

  Also in the present embodiment, the outer circumference L0 discrimination area is the inner circumference L0 judgment area 11-2, the outer circumference L1 judgment area is the inner circumference L1 judgment area 12-2, and the outer circumference L2 judgment area is The configuration is almost the same as that of the inner circumference L2 discrimination region 13-2. However, it is not necessary to align the period in which the pits are formed with respect to the rotation angle between the inner peripheral side and the outer peripheral side. The pit length may be a combination other than the above as long as it can be used as a recording layer discrimination.

  The optical disc 1 according to the present embodiment can achieve the same effects as the optical disc 1 according to the first embodiment.

[Optical Disc According to Third Embodiment of the Present Invention]
Next, an optical disc according to a third embodiment of the present invention will be described. The optical disc according to the present embodiment is basically configured similarly to the optical disc according to the first embodiment, but the configuration of the recording layer discrimination area is different.

  FIGS. 13 to 15 respectively illustrate the configuration of information tracks in the inner circumference L0 discrimination area 11-3, the inner circumference L1 discrimination area 12-3, and the inner circumference L2 discrimination area 13-3 according to the present embodiment. FIG. As shown in the figure, in this embodiment, the pits 113-3, 123-3, and 133-3 have the same period as that of the grooves 111, 121, and 131 according to the first embodiment, respectively. Meander periodically in the inner and outer circumferential directions. Further, the pits 113-3, 123-3, and 133-3 are formed with the same period as the pits 113-2, 123-2, and 133-2 according to the second embodiment, respectively.

  Also in the present embodiment, the outer circumference L0 discrimination area is the inner circumference L0 discrimination area 11-3, the outer circumference L1 judgment area is the inner circumference L1 judgment area 12-3, and the outer circumference L2 judgment area is The configuration is almost the same as that of the inner circumference L2 discrimination region 13-3. However, it is not necessary to make the period in which the pits meander and the period in which the pits are formed with respect to the rotation angle between the inner peripheral side and the outer peripheral side.

  The optical disc 1 according to the present embodiment can achieve the same effects as the optical disc 1 according to the first embodiment. In the present embodiment, the recording layer includes both the period in which the pits 113-3, 123-3, and 133-3 meander and the interval at which the pits 113-3, 123-3, and 133-3 are formed. Therefore, it is possible to discriminate the recording layer more reliably and at high speed.

[Optical Discs According to Other Embodiments]
The optical discs according to the first to third embodiments all have three recording layers. However, if the optical disc has two or more recording layers, the recording layer can be suitably determined. desirable. Therefore, the present invention is applicable to all optical disks having two or more recording layers.

  In the first to third embodiments, information is recorded from the inner circumference side to the outer circumference side in the recording layer L0, and the subsequent information is recorded from the outer circumference side to the inner circumference side in the recording layer L1. In the recording layer L2, further information is recorded from the inner circumference side to the outer circumference side. However, the recording direction of information can be changed as appropriate.

  For example, in the third embodiment, the pits 113-3, 123-3, and 133-3 may all be formed with the same length and the same interval.

  In the third embodiment, the cycle in which the pits 113-3, 123-3, and 133-3 meander, and the interval at which the pits 113-3, 123-3, and 133-3 are formed, Both are used for discriminating the recording layer. For example, as shown in FIG. 16, the pit 113-4 is meandered at a predetermined cycle, the discriminating recording layer is discriminated by this cycle, and the interval at which the pit 113-4 is formed. It is also possible to record information on the recording layer. The information relating to the recording layer referred to here is information different from the content information, for example, the number of recording layers of the optical disc (three layers in the first to third embodiments), the recording layer, and the like. The start position, end position, etc. of the content information can be considered.

  In the second embodiment, it is possible to include information relating to the recording layer by making the interval between pits constant and modulating the length of the pits.

  In the first to third embodiments, the information track in the recording layer discrimination area is formed only by the groove and land, or is formed only by the pit. However, for example, as shown in FIG. 17, it is also possible to form an information track from the groove 111-5, the land 112-5, and the pit 113-5. In FIG. 17, a so-called in-pit method is used in which the pit 113-5 is formed on the groove 111-5, but a so-called on-pit method is used in which the pit 113-5 is formed on the land 112-5. It is also possible to form pits 113-5 on both the grooves 111-5 and the lands 112-5.

  In the first to third embodiments, the recording layer discrimination area on the inner circumference side corresponds to the inner circumference edge of the first protection area from the radial position corresponding to the inner circumference edge or outer circumference edge of the BCA. The recording layer discriminating area on the outer peripheral side is provided in the area on the outer peripheral side from the radial position corresponding to the outer peripheral end of the lead-out area in the area up to the radial position where the recording layer discriminating area is formed. It can be changed as appropriate. For example, in the recording layers L0 and L1, it is possible to provide the recording layer discriminating area on the outer peripheral side in an area overlapping with the lead-out area 34 (FIG. 4).

  In the first to third embodiments, the recording layer discrimination area is provided in all the recording layers. However, for example, even if the inner L0 discrimination area IL0 is not provided in the recording layer L0, it can be easily discriminated from a signal obtained when another recording layer is read. Therefore, in some cases, the recording layer discrimination area for a predetermined recording layer can be omitted. Further, when the inner circumference L0 discrimination area is omitted, for example, the BCA can be expanded.

  In the first to third embodiments, the recording layer discriminating areas are provided on the inner peripheral side and the outer peripheral side of each recording layer. However, for example, it is possible to provide a recording layer discrimination area only on the inner circumference side of the recording layer, and for a recording layer in which data is written from the inner circumference side, a recording layer discrimination area is provided only on the inner circumference side, For a recording layer in which data is written from the outer peripheral side, a recording layer discriminating area may be provided only on the outer peripheral side.

  In the first embodiment, the groove meanders at a predetermined cycle, but the land can meander at a predetermined cycle.

  DESCRIPTION OF SYMBOLS 1 ... Optical disk, 10 ... Inner peripheral side area | region, 11 ... Inner peripheral side L0 discriminating area, 12 ... Inner peripheral side L1 discriminating area, 13 ... Inner peripheral side L2 discriminating area, 20 ... Data area, 30 ... Outer peripheral side area, 31 ... outer peripheral side L0 discriminating region, 32 ... outer peripheral side L1 discriminating region, 33 ... outer peripheral side L2 discriminating region, 34 ... lead-out region, 111, 121, 131 ... groove, 112, 122, 132 ... land, 113-2, 123 -2, 133-2 ... Pit.

Claims (6)

At least two recording layers for recording information on a spiral information track formed from one of the inner peripheral side and the outer peripheral side to the other,
The recording layer is
An inner peripheral region located on the inner peripheral side, and
A data area for recording content information, located on the outer peripheral side with respect to the inner peripheral side area;
An outer peripheral region located on the outer peripheral side with respect to the data region, and
At least one of the inner and outer peripheral areas of the plurality of recording layers has the information track adjacent to the information track at different periods along the information track in the same recording layer. An optical disc comprising a recording layer discriminating area on which recording layer discriminating information is formed so that phases are matched between tracks. The optical disk according to claim 1, wherein the recording layer discrimination area is provided outside an area requiring tracking control. The optical disk according to claim 1, wherein the recording layer discrimination area is provided on an outer peripheral side of a BCA (Burst Cutting Area). The inner peripheral area of the predetermined recording layer has a BCA (Burst Cutting Area) and a first protection area provided on the outer peripheral side of the BCA,
The outer peripheral side region of another recording layer different from the predetermined recording layer has a lead-out region,
The recording layer discrimination area includes an area from a radial position corresponding to the inner peripheral edge or outer peripheral edge of the BCA to a radial position corresponding to the inner peripheral edge of the first protective area, and an outer periphery of the lead-out area. The optical disc according to any one of claims 1 to 3, wherein the optical disc is provided in at least one of the regions on the outer peripheral side of the radial position corresponding to the end. The optical disc according to any one of claims 1 to 4, wherein the recording layer discrimination information includes a plurality of pits formed in the information track. The optical disk according to claim 1, wherein the recording layer discrimination information includes a wobble groove formed in the information track.

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