WO2013179396A1 - Record/play device and method - Google Patents

Record/play device and method Download PDF

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Publication number
WO2013179396A1
WO2013179396A1 PCT/JP2012/063800 JP2012063800W WO2013179396A1 WO 2013179396 A1 WO2013179396 A1 WO 2013179396A1 JP 2012063800 W JP2012063800 W JP 2012063800W WO 2013179396 A1 WO2013179396 A1 WO 2013179396A1
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WO
WIPO (PCT)
Prior art keywords
track
recording
guide
mark
center
Prior art date
Application number
PCT/JP2012/063800
Other languages
French (fr)
Japanese (ja)
Inventor
琢也 白戸
吉田　昌義
小林　秀樹
小笠原　昌和
田切　孝夫
Original Assignee
パイオニア株式会社
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Priority to PCT/JP2012/063800 priority Critical patent/WO2013179396A1/en
Publication of WO2013179396A1 publication Critical patent/WO2013179396A1/en

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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/007—Arrangement of the information on the record carrier, e.g. form of tracks, actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped; Sequential information structures, e.g. sectoring or header formats within a track
    • G11B7/00772—Arrangement of the information on the record carrier, e.g. form of tracks, actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped; Sequential information structures, e.g. sectoring or header formats within a track on record carriers storing information in the form of optical interference patterns, e.g. holograms
    • G11B7/00781—Auxiliary information, e.g. index marks, address marks, pre-pits, gray codes
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B7/0901—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following only
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B7/0938—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following servo format, e.g. guide tracks, pilot signals
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/2403—Layers; Shape, structure or physical properties thereof
    • G11B7/24047—Substrates
    • G11B7/2405—Substrates being also used as track layers of pre-formatted layers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B2007/0003—Recording, reproducing or erasing systems characterised by the structure or type of the carrier
    • G11B2007/0009—Recording, reproducing or erasing systems characterised by the structure or type of the carrier for carriers having data stored in three dimensions, e.g. volume storage
    • G11B2007/0013—Recording, reproducing or erasing systems characterised by the structure or type of the carrier for carriers having data stored in three dimensions, e.g. volume storage for carriers having multiple discrete layers

Definitions

  • the present invention relates to a technical field of a recording / reproducing apparatus and method for performing at least one of a recording operation and a reproducing operation with respect to a recording medium such as an optical disc having a large number of recording layers.
  • a recording medium including a large number of recording layers for example, a recording medium having a plurality of recording layers that are actually targets of at least one of a recording operation and a reproducing operation, and a guide layer on which a tracking guide track is formed (for example, A so-called guide layer separation type optical disc) is known (see Patent Document 1).
  • a recording / reproducing apparatus that performs at least one of a recording operation and a reproducing operation with respect to such a recording medium has a guide laser beam for reading the guide track of the guide layer, and at least one of the recording operation and the reproducing operation with respect to the recording layer.
  • the recording / reproducing laser beam is irradiated.
  • the recording / reproducing apparatus performs at least one of the recording operation and the reproducing operation by irradiating the recording layer with the recording / reproducing laser beam while performing tracking control based on the push-pull signal obtained from the return light of the guide laser beam.
  • Patent Documents 2 to 11 are cited as prior art documents related to the present invention described later.
  • Japanese Patent No. 4037034 Japanese Patent Laid-Open No. 10-308037
  • Japanese Patent No. 3729467 Japanese Patent No. 3665588 Japanese Patent No. 374944 JP 2003-323725 A JP 2004-177871 A JP-A-8-279160
  • Japanese Patent Laid-Open No. 8-45080 Japanese Patent No. 3205154 Japanese Patent No. 3693913
  • the recording / reproducing apparatus when data is recorded on the guide layer by forming the combination of the recording mark and the recording space in the guide layer, the recording / reproducing apparatus only detects the push-pull signal for tracking from the return light of the guide laser beam. Instead, it is necessary to acquire an RF signal (so-called sum signal) for reading the control information.
  • RF signal so-called sum signal
  • acquiring both the push-pull signal and the RF signal at the same time may have some influence on the accuracy of acquiring the push-pull signal. This causes a technical problem. In other words, obtaining both the push-pull signal and the RF signal at the same time causes a technical problem that the tracking control, which is the original purpose of the guide layer, may have some influence.
  • each of a plurality of guide tracks on the guide layer shifts a pair of recording marks that are shifted equidistant from the center of each guide track to the left and right.
  • Development of a technique for forming the same information mark group in which the two are combined is underway (for example, Japanese Patent Application No. 2012-010085).
  • the same information mark group is formed on each of the plurality of guide tracks, one information mark formed on each of the plurality of guide tracks having one guide track as a center track. Groups are also formed on other guide tracks adjacent to one guide track.
  • one information mark group should be read by using a guide laser beam whose spot center coincides with one guide track, but a guide laser beam whose spot center coincides with another guide track.
  • One information mark group may be read.
  • the information mark group indicates the address information
  • a recording / reproducing apparatus that has read one information mark group using a guide laser beam whose spot center coincides with another guide track erroneously recognizes that the other guide track is one guide track.
  • a center track located near the center among the plurality of guide tracks can be preferably determined.
  • a guide laser beam having a spot center aligned with one guide track is used to form each of the plurality of guide tracks having the one guide track as the center track.
  • This information mark group is preferably read.
  • a plurality of guide tracks having the one guide track as the center track using the guide laser beam having the spot center matched to another guide track different from the one guide track is not generated.
  • the present invention provides a plurality of information mark groups formed on an optical disc having a large number of recording layers as described above in order to suitably read information mark groups recorded on a plurality of guide tracks on the guide layer. It is an object of the present invention to provide a recording / reproducing apparatus and method for performing at least one of a recording operation and a reproducing operation with respect to a recording medium capable of suitably discriminating a center track located near the center of guide tracks.
  • a recording / reproducing apparatus includes: (i-1) a guide layer in which a guide track for tracking is formed; and (i-2) a plurality of recording layers stacked on the guide layer.
  • the guide layer includes (ii-1) an information mark group formed on each of a plurality of adjacent guide tracks, and (ii-2) the information layer.
  • a recording / reproducing apparatus that performs at least one of a recording operation and a reproducing operation with respect to a recording medium including a recording mark, wherein a first push-pull signal is generated from a return light of the guide laser light irradiated to the discrimination mark group.
  • a recording / reproducing method includes (i-1) a guide layer in which a guide track for tracking is formed, and (i-2) a plurality of recording layers stacked on the guide layer.
  • the guide layer includes (ii-1) an information mark group formed on each of a plurality of adjacent guide tracks, and (ii-2) the information layer.
  • It is sectional drawing which shows the cross section of an optical disk with the irradiation aspect of a guide laser beam and a recording / reproducing laser beam.
  • It is a top view which shows the structure of a pair of information recording mark which comprises the information mark group formed in a groove track.
  • It is a top view which shows the structure of a pair of information recording mark which comprises the information mark group formed in a land track.
  • FIG. 11 is a flowchart showing an operation of discriminating a center track using the discrimination mark group shown in FIG.
  • It is a data structure figure which shows the data structure of a guide layer (further, a recording layer).
  • the signal level of the push-pull signal obtained from the return light of the guide laser beam that traces on the groove track on which the discrimination mark group of the first modification is formed is determined as the discrimination mark of the first modification formed on the groove track.
  • the signal level of the push-pull signal obtained from the return light of the guide laser beam that traces on the land track on which the discrimination mark group of the second modification is formed is used as the discrimination mark of the second modification formed on the land track. It is a graph shown in association with a group configuration.
  • FIG. 24 is a flowchart showing an operation of discriminating the center track using the discrimination mark group of the second modification shown in FIG. 23.
  • FIG. The signal level of the push-pull signal obtained from the return light of the guide laser beam that traces on the land track on which the discrimination mark group of the third modification is formed is used as the discrimination mark of the third modification formed on the land track. It is a graph shown in association with a group configuration.
  • FIG. 26 is a flowchart showing an operation of discriminating a center track using the discrimination mark group of the third modification shown in FIG. 25.
  • FIG. It is a top view which shows the structure of the discrimination mark group of the 4th modification formed in a land track. It is a flowchart which shows the operation
  • the recording / reproducing apparatus of the present embodiment includes (i-1) a guide layer in which a guide track for tracking is formed, and (i-2) a recording layer including a plurality of recording layers stacked on the guide layer.
  • the guide layer is formed with (ii-1) an information mark group formed on each of a plurality of guide tracks adjacent to each other; and (ii-2) the information mark group is formed.
  • a discriminating mark group for discriminating a center track that is a guide track located near the center of the plurality of guide tracks, and (iii) the discriminating mark group is (iii- 1) a pair of discriminating recording marks shifted by a predetermined distance from side to side with respect to the track center of the center track, and (iii-2) the width of each discriminating recording mark is equal to the width of the guide track Includes a pair of discriminating recording marks that are more than doubled
  • a recording / reproducing apparatus that performs at least one of a recording operation and a reproducing operation with respect to a recording medium, and that detects a first push-pull signal from a return light of the guide laser light irradiated to the discrimination mark group And a determining means for determining whether or not the guide track traced by the guide laser beam is the center track based on the first push-pull signal detected by the detecting means.
  • the recording medium that is the target of at least one of the recording operation and the reproducing operation by the recording / reproducing apparatus of the present embodiment includes a guide layer and a plurality of recording layers.
  • a tracking track for tracking is formed on the guide layer. Therefore, a recording / reproducing apparatus that performs at least one of a recording operation and a reproducing operation on the recording medium (more specifically, on a plurality of recording layers included in the recording medium) irradiates the guide layer.
  • a push-pull signal corresponding to the positional relationship between the guide track and the beam spot of the guide laser light can be acquired.
  • the recording / reproducing apparatus can perform tracking control based on the push-pull signal.
  • an information mark group and a discrimination mark group are formed on the guide layer.
  • the information mark group is a mark formed on the guide layer in order to record desired bit data (for example, bit data indicating control information such as address information, clock information, and recording start timing information) on the guide layer.
  • desired bit data for example, bit data indicating control information such as address information, clock information, and recording start timing information
  • the information mark group is formed on each of a plurality of guide tracks adjacent to each other. That is, in the present embodiment, the same information mark group is formed in each of a plurality of guide tracks adjacent to each other. More specifically, for example, one information mark group is formed in each of a plurality of guide tracks in which one guide track is located near the center (that is, one guide track serves as a center track). .
  • one information mark group is Different other information mark groups are formed.
  • the bit data can be recorded on the guide layer using the information mark groups.
  • the discrimination mark group is a mark for discriminating a center track which is a guide track located near the center (in other words, closest to the center) among a plurality of guide tracks on which the same information mark group is formed. Is a group.
  • the discrimination mark group includes a pair of discrimination recording marks.
  • the discrimination mark group may include only one pair of discrimination recording marks, or may include a plurality of pairs of discrimination recording marks.
  • the pair of discriminating recording marks is a pair of recording marks shifted by a predetermined distance from side to side with respect to the track center of the center track.
  • the pair of determination recording marks includes a recording mark shifted to the left by a predetermined distance with respect to the track center of the center track and a recording mark shifted to the right by a predetermined distance with respect to the track center of the center track.
  • a pair of recording marks the width of each of the pair of discrimination recording marks (that is, the length in the direction perpendicular to the traveling direction of the guide track and along the radial direction of the recording medium) is the width of the guide track. More than twice. That is, each of the pair of determination recording marks is formed so as to be distributed over two or more guide tracks.
  • the discrimination mark group includes a pair of first discrimination recording marks shifted by a first distance from the center of the center track to the left and right and a second distance from the center of the center track to the left and right (however, the second distance). May be different from the first distance) and may include a pair of shifted second discrimination recording marks.
  • the discrimination mark group includes a pair of first discrimination recording marks shifted by a first distance to the left and right from the track center of the center track, and a pair of shifts shifted by a first distance to the left and right from the track center of the center track. It may include a second discrimination recording mark.
  • the discrimination mark group is formed to be paired with the same information mark group.
  • a plurality of different information mark groups are formed in each of a plurality of guide tracks in which a certain guide track is a center track
  • a plurality of determinations respectively corresponding to the plurality of different information mark groups A mark group may be formed.
  • the track of the first guide track that is the center track so that the first guide track corresponds to the same first information mark group formed on each of the plurality of guide tracks that become the center track.
  • a first discriminating mark group including a pair of first discriminating recording marks shifted by a predetermined distance from the center to the right and left is formed, while the first guide track is formed on each of a plurality of guide tracks serving as a center track.
  • a mark group may be formed.
  • a single corresponding to a plurality of different information mark groups in common The discriminating mark group may be formed.
  • the first guide track corresponds to both the same first information mark group and the same second information mark group formed on each of the plurality of guide tracks serving as the center track.
  • a first discriminating mark group including a pair of first discriminating recording marks shifted by a predetermined distance from the track center of the first guide track which is the center track may be formed.
  • the recording / reproducing apparatus of this embodiment performs at least one of a recording operation and a reproducing operation on the recording medium of this embodiment in which such a discrimination mark group is formed.
  • the detection means acquires the first push-pull signal from the return light of the guide laser light irradiated to the discrimination mark group.
  • the spot center of the beam spot on the guide layer of the guide laser beam is located on the guide track on which the discrimination mark group is formed.
  • the discriminating means is based on the first push-pull signal (that is, the first push-pull signal whose signal level changes according to the combination of a plurality of pairs of discriminating recording marks constituting the discriminating mark group). It is determined whether or not the guide track currently traced by the laser beam (that is, the guide track on which the spot center is located) is the center track. For this reason, the recording / reproducing apparatus of this embodiment has the following advantages.
  • the discrimination mark group formed on the guide layer is a mark group in which a plurality of discrimination record marks that are shifted by a predetermined distance from the center of the center track to the left and right are combined. It is. Therefore, even if such a discrimination mark group is formed on the guide layer, the average value of signal level fluctuations that can be exerted on the push-pull signal by the discrimination mark group is zero (however, it is substantially regarded as zero. Including the margin to obtain). Therefore, the presence of the discrimination mark group has little or no adverse effect on the tracking control based on the push-pull signal. Therefore, the recording / reproducing apparatus can perform at least one of the recording operation and the reproducing operation with respect to the plurality of recording layers while performing suitable tracking control.
  • the center track of the plurality of guide tracks on which the same information mark group is formed is discriminated according to the difference in the combination of the plurality of pairs of discrimination recording marks constituting the discrimination mark group. be able to.
  • Such a difference in the combination of a plurality of pairs of discriminating recording marks can be easily read by monitoring the change in the instantaneous value of the signal level fluctuation of the push-pull signal. Therefore, according to the present embodiment, the determination recording mark that can be read using the push-pull signal can be formed on the guide layer. In other words, according to the present embodiment, it is possible to form a determination recording mark on the guide layer that does not need to be read using an RF signal (in other words, a total signal).
  • the recording / reproducing apparatus can determine the center track among the plurality of guide tracks on which the same information mark group is formed based on the push-pull signal. As a result, the recording / reproducing apparatus can perform at least one of the recording operation and the reproducing operation with respect to the plurality of recording layers while preferably reading the bit data corresponding to the information mark group formed in advance on the guide layer.
  • the center track of the plurality of guide tracks on which the same information mark group is formed cannot be discriminated, the following technical problems will occur. Specifically, in the present embodiment, since the same information mark group is formed on each of the plurality of guide tracks, one formed on each of the plurality of guide tracks having one guide track as the center track. This information mark group is also formed on another guide track adjacent to one guide track. Therefore, one information mark group should be read by using a guide laser beam whose spot center coincides with one guide track, but a guide laser beam whose spot center coincides with another guide track. One information mark group may be read. At this time, for example, when the information mark group indicates the address information, there is a risk of erroneous detection of the address information.
  • a recording / reproducing apparatus that has read one information mark group using a guide laser beam whose spot center coincides with another guide track erroneously recognizes that the other guide track is one guide track.
  • the recording / reproducing apparatus can determine the center track among a plurality of guide tracks on which the same information mark group is formed. That is, the recording / reproducing apparatus can determine whether or not the guide track currently being traced is the center track. Therefore, there is a possibility that one information mark group formed on each of a plurality of guide tracks having one guide track as a center track may be read using a guide laser beam whose spot center coincides with another guide track. Little or no. Thus, there is little or no risk of the technical problems described above.
  • the width of each of the pair of discrimination recording marks is at least twice the width of the guide track. Accordingly, the recording / reproducing apparatus can discriminate the center track according to the discrimination mark group without being affected by the focus offset deviation (so-called defocus) of the guide laser beam.
  • a plurality of information mark groups are formed.
  • a center track located near the center of the guide tracks can be suitably determined.
  • the determination means has a signal level of the first push-pull signal that changes according to a combination of the pair of determination recording marks constituting the determination mark group. Based on this, it is determined whether or not the guide track traced by the guide laser beam is the center track.
  • the discriminating means traces the guide laser beam based on the change in the signal level of the first push-pull signal according to the combination of the pair of discriminating recording marks constituting the discriminating mark group. Whether or not the guide track is the center track can be suitably determined.
  • the determination means determines the signal level of the first push-pull signal that changes according to the combination of the pair of determination recording marks constituting the determination mark group. Then, by comparing with a predetermined threshold value for each predetermined processing unit, it is determined whether or not the guide track traced by the guide laser beam is the center track.
  • the discriminating means can specify the aspect of the change in the signal level of the first push-pull signal for each predetermined processing unit relatively easily.
  • the discriminating means has the guide track traced by the guide laser beam based on the change in the signal level of the first push-pull signal according to the combination of the pair of discriminating recording marks constituting the discriminating mark group. It can be suitably determined whether or not it is a center track.
  • the detection means further detects a second push-pull signal from a return light of the guide laser light irradiated to the information mark group, and the second push-pull Based on the signal, bit data corresponding to the information mark group formed on each of the plurality of guide tracks in which the guide track determined to be the center track by the determining means is located near the center.
  • An acquisition means for acquiring, and a recording / reproducing means for performing at least one of the recording operation and the reproducing operation for the plurality of recording layers based on the bit data acquired by the acquiring means are further provided.
  • the acquisition unit obtains the bit data corresponding to the information mark group based on the second push-pull signal obtained from the return light of the guide laser beam (for example, as described later, the information mark group is Bit data corresponding to a combination of a pair of recording marks for information).
  • the recording / reproducing means can perform at least one of a recording operation and a reproducing operation with respect to the plurality of recording layers based on the bit data.
  • the acquisition unit instead of acquiring the bit data corresponding to all the information mark groups irradiated with the guide laser beam, the acquisition unit has the guide track determined to be the center track near the center. Bit data corresponding to the information mark group formed on each of the plurality of guide tracks is selectively acquired. Therefore, the acquisition means is formed on each of a plurality of guide tracks having one guide track as the center track, based on the second push-pull signal obtained from the guide laser beam whose spot center coincides with the other guide tracks. There is little or no risk of acquiring bit data corresponding to one information mark group. Thus, there is little or no risk of the technical problems described above.
  • the acquisition unit does not acquire bit data corresponding to the information mark group formed on the guide track that is not determined to be the center track by the determination unit.
  • the acquisition unit is configured to detect a plurality of guide tracks having one guide track as the center track based on the second push-pull signal obtained from the guide laser beam having the spot center aligned with another guide track. There is little or no risk of acquiring bit data corresponding to one information mark group formed respectively.
  • the acquisition means is not based on the second push-pull signal obtained from the guide laser beam whose spot center is coincident with one guide track, each of the plurality of guide tracks having the one guide track as the center track is provided. Bit data corresponding to one formed information mark group is not acquired. Thus, there is little or no risk of the technical problems described above.
  • the recording / reproducing means is obtained by (i) accumulating a predetermined number of the bit data obtained by the obtaining means, and (ii) performing error correction processing on the bit data accumulated by the predetermined number collectively. Based on the bit data, at least one of the recording operation and the reproducing operation for the plurality of recording layers is performed.
  • the recording / reproducing means is formed on each of the plurality of guide tracks in which the bit data selectively acquired by the acquiring means (that is, the guide track determined to be the center track is located near the center). Based on the bit data corresponding to the information mark group), at least one of the recording operation and the reproducing operation can be performed.
  • the predetermined number is the number of bits of a word constituting the ECC block.
  • the bit data selectively acquired by the acquisition means (that is, the information mark group formed on each of the plurality of guide tracks in which the guide track determined to be the center track is located near the center) Based on the corresponding bit data), at least one of the recording operation and the reproducing operation can be performed.
  • the determination mark group is formed at (i) the pair of determination recording marks formed at the same rotational phase position and (ii) at different rotational phase positions. At least one of the pair of discrimination recording marks.
  • the pair of determination recording marks is a recording mark shifted to the left by a predetermined distance with respect to the track center of the center track and a recording mark shifted to the right by a predetermined distance with respect to the track center of the center track. It may be a pair of recording marks including marks and a pair of recording marks formed at the same rotational phase position.
  • the pair of determination recording marks is a recording mark shifted to the left by a predetermined distance with respect to the track center of the center track, and is formed at the first rotational phase position and the track center of the center track.
  • the pair of determination recording marks formed at the same rotational phase position includes: (i) the absolute value of the signal level of the push-pull signal obtained by irradiating the pair of determination recording marks with guide laser light whose spot center coincides with the center track is equal to or less than a first threshold; and (ii) It is obtained by irradiating the pair of determination recording marks with the guide laser light whose spot center coincides with a guide track other than the center track among the plurality of guide tracks on which the information mark group is formed.
  • the absolute value of the signal level of the push-pull signal to be generated is larger than the first threshold.
  • the recording / reproducing apparatus can appropriately discriminate the center track by monitoring the signal level of the push-pull signal obtained from the pair of discriminating recording marks formed at the same rotational phase position. it can.
  • a pair of determination recording marks shifted by a predetermined distance from the center of the center track to the left and right are formed at the same rotational phase position. Therefore, if the pair of determination recording marks is irradiated with the guide laser beam whose spot center coincides with the center track, the distribution mode of the pair of determination recording marks with reference to the spot center becomes symmetrical (or It approaches a symmetrical state). For this reason, the signal level of the push-pull signal becomes relatively small (for example, approaches zero).
  • the distribution mode of the pair of determination recording marks with reference to the spot center is symmetrical. (Or move away from the symmetrical state). For this reason, the signal level of the push-pull signal becomes relatively high. In other words, if the absolute value of the signal level of the push-pull signal obtained in a state where the guide laser beam is irradiated to a certain guide track, this guide track is the center track. It is determined that there is a high possibility of being.
  • the absolute value of the signal level of the push-pull signal obtained in a state in which a guide track is irradiated with a guide laser beam is greater than the first threshold (or greater than or equal to the first threshold), this It is determined that there is a high possibility that the guide track is not the center track.
  • the pair of discrimination recording marks formed at different rotational phase positions is the center.
  • the absolute value of the signal level of the push-pull signal obtained by irradiating the pair of determination recording marks with the guide laser beam whose spot center coincides with the track is formed to be larger than the first threshold value.
  • the recording / reproducing apparatus can suitably discriminate the center track by monitoring the signal level of the push-pull signal obtained from the pair of discrimination recording marks formed at different rotational phase positions. .
  • a pair of discrimination recording marks shifted by a predetermined distance from the center of the center track to the left and right are formed at different rotational phase positions. Accordingly, if the pair of determination recording marks is irradiated with the guide laser beam whose spot center coincides with the center track, the distribution mode of the pair of determination recording marks based on the spot center is not symmetrical (or Move away from the symmetrical state). For this reason, the signal level of the push-pull signal becomes relatively high. That is, if the absolute value of the signal level of the push-pull signal obtained in a state where the guide laser beam is irradiated to a certain guide track is greater than the first threshold, it is highly likely that this guide track is the center track. Is determined.
  • the determination mark group includes (i) a spot center in each of the plurality of guide tracks on which the determination mark group is formed. (Ii) Spots on each guide track so that two or more first regions where the absolute value of the signal level of the push-pull signal obtained by irradiating the matching guide laser light is larger than the first threshold value are included. Two or more second regions in which the absolute value of the signal level of the push-pull signal obtained by irradiating the guide laser light having the same center is equal to or smaller than a second threshold value smaller than the first threshold value are included. Or (iii) the first region and the second region are formed so as to include one or more each.
  • the recording / reproducing apparatus performs the same information processing according to the difference in the combination of a plurality of pairs of determination recording marks constituting the determination mark group.
  • the center track among the plurality of guide tracks formed with the mark group can be more suitably discriminated.
  • the width of each of the pair of discrimination recording marks is one of the widths of the beam spots formed on the guide layer by the guide laser light applied to the guide layer. / Two or more times.
  • the width of each of the pair of discrimination recording marks is 1 ⁇ 2 times or more the width of the beam spot. Accordingly, the recording / reproducing apparatus can discriminate the center track according to the discrimination mark group without being affected by the focus offset deviation (so-called defocus) of the guide laser beam.
  • beam spot width is intended to indicate the width of the beam spot in consideration of a margin that may vary depending on the focus offset state (for example, the amount of focus offset).
  • the guide track includes alternately formed groove tracks and land tracks
  • the determination mark group includes (i) the information mark group is formed.
  • a discrimination mark group for identifying a groove center track located near the center among the plurality of groove tracks (i-1) shifted by a predetermined distance from side to side with respect to the track center of the groove center track.
  • a pair of determination recording marks, and (ii-2) a pair of determination recording marks each having a width of at least twice the width of the groove track.
  • the mark group is (ii) an identification for identifying a land center track located near the center among the plurality of land tracks on which the information mark group is formed.
  • each discriminating recording mark Includes a pair of discriminating recording marks whose width is at least twice the width of the land track.
  • both the discrimination mark group corresponding to the groove track and the discrimination mark group corresponding to the land track are formed. Therefore, when the recording / reproducing apparatus irradiates the groove track with the guide laser beam, the same information mark group is formed according to the difference in the combination of the plurality of pairs of determination recording marks constituting the determination mark group. Of the plurality of groove tracks, the groove center track can be discriminated more suitably. Similarly, when the land track is irradiated with the guide laser light, the same information mark group is formed according to the difference in the combination of a plurality of pairs of determination recording marks constituting the determination mark group. Among the plurality of land tracks, the land center track can be discriminated more suitably.
  • ⁇ 14> In another aspect of the recording / reproducing apparatus of the present embodiment, at least two guide tracks out of a plurality of guide tracks included in a beam spot formed on the guide layer by the guide laser beam irradiated on the guide layer.
  • the same information mark group is formed by combining a pair of information recording marks shifted by a predetermined distance from side to side with respect to the track center of each guide track at the same rotational phase position.
  • the information mark group is formed on the guide layer.
  • the information mark group is formed at the same rotational phase position of at least two guide tracks among a plurality of guide tracks included in the beam spot formed by the guide laser beam on the guide layer.
  • the same information mark group indicating the same bit data (for example, bit data of 1 bit to several bits or a dozen bits) is at least one of a plurality of guide tracks included in the beam spot of the guide laser beam.
  • Each of the two guide tracks is formed so as to be adjacent along a direction orthogonal to the traveling direction of the guide track.
  • the information mark group is formed on each of at least two guide tracks among a plurality of guide tracks included in the beam spot formed by the guide laser beam on the guide layer. That is, the number of guide tracks on which the same information mark group is formed is equal to or less than the number of guide tracks included in the beam spot of the guide laser beam and equal to or more than two.
  • the information mark group formed at the same rotational phase position of each of the at least two guide tracks is combined with a pair of information recording marks shifted by a predetermined distance from side to side with respect to the track center of the guide track.
  • the mark group is combined in any manner.
  • a recording mark shifted by a predetermined distance to the left with respect to the track center and a recording mark shifted by a predetermined distance to the right with respect to the track center are arranged in the traveling direction of the guide track.
  • the information mark group may be a mark group in which only one pair of such information recording marks is combined (that is, a mark group that matches the pair of information recording marks themselves).
  • a mark group in which such a pair of information recording marks is combined in an arbitrary manner may be used.
  • the information mark group is a mark group in which such a pair of information recording marks and other recording marks (for example, a recording mark located on the center of the track) are combined in an arbitrary manner. It may be.
  • the same rotational phase position of at least two of the kth (where k is an integer equal to or greater than 1) th guide track, the (k + 1) th guide track, and the (k + 2) th guide track have the same rotational phase position.
  • An information mark group is formed.
  • the rotation phase position of the kth guide track is x (where x is a real number satisfying 0 ⁇ x ⁇ 360) ° and the rotation phase position of the k + 2th guide track is x °.
  • the same information mark group is formed.
  • the position where the rotational phase position of the first guide track is 10 ° and the position where the rotational phase position of the third guide track is 10 ° are set to the left with reference to the track center.
  • the fourth guide track has a rotational phase position of 60 ° and the sixth guide track has a rotational phase position of 60 °.
  • An information mark group consisting of a pair of information recording marks arranged in this order along the advancing direction of the guide track with the recording mark being recorded and the recording mark shifted to the left by a predetermined distance with respect to the track center May be formed.
  • all of the information mark groups formed on the guide layer may not be a mark group in which the pair of information recording marks described above are combined.
  • a part of the information mark group formed on the guide layer is a mark group that becomes the above-described pair of information recording marks themselves (or a combination of the above-described pair of information recording marks), while the guide layer
  • Another part of the information mark group formed on the recording medium may be an arbitrary recording mark that does not include the pair of information recording marks described above (for example, a recording mark located on the center of the track).
  • the recording medium according to this embodiment in which such information mark groups are formed has the following advantages.
  • the information mark group formed on the guide layer is a mark group in which a pair of information recording marks shifted by a predetermined distance from side to side with respect to the track center of the guide track is combined. is there. For this reason, even if such an information mark group is formed on the guide layer, the average value of signal level fluctuations that can be exerted on the push-pull signal by the information mark group is zero (however, it is substantially regarded as zero. Including the margin to obtain). Therefore, the presence of the information mark group has little or no adverse effect on the tracking control based on the push-pull signal. Therefore, the recording / reproducing apparatus can perform at least one of the recording operation and the reproducing operation with respect to the plurality of recording layers while performing suitable tracking control.
  • bit data that can be read using a push-pull signal can be recorded on the guide layer.
  • bit data that does not need to be read using an RF signal in other words, a sum signal
  • the recording / reproducing apparatus performs at least one of the recording operation and the reproducing operation on the plurality of recording layers while preferably reading the bit data corresponding to the information mark group formed in advance on the guide layer based on the push-pull signal. It can be carried out.
  • the same information mark group is formed at the same rotational phase position of each of at least two guide tracks included in the beam spot of the guide laser beam. . Therefore, as will be described in detail later with reference to the drawings, the recording / reproducing apparatus reads bit data corresponding to the information mark group without being affected by the focus offset deviation (so-called defocus) of the guide laser beam. be able to.
  • data for example, the above-described bit data
  • the recording medium of the present embodiment data (for example, the above-described bit data) is suitably applied to the guide layer on which the tracking guide track is formed while suppressing the influence on the tracking control. Can be recorded.
  • the same information mark is provided at the same rotational phase position of each of the plurality of guide tracks.
  • a group of marks is formed.
  • the same information mark group is formed at the same rotational phase position of each of the plurality of guide tracks included in the beam spot of the guide laser beam. That is, the same information mark group is formed at all the same rotational phase positions of the plurality of guide tracks included in the beam spot of the guide laser beam. That is, the number of guide tracks on which the same information mark group is formed is substantially equal to the number of guide tracks included in the beam spot of the guide laser beam.
  • substantially equal includes a state that can be regarded as being approximately equal in consideration of a margin of the size of a beam spot that may vary depending on the state of focus offset (for example, the amount of focus offset). It is. Therefore, as will be described in detail later with reference to the drawings, the recording / reproducing apparatus is not affected more by the deviation (so-called defocus) of the focus offset of the guide laser beam, and the bit data corresponding to the information mark group. Can be read.
  • the guide track includes a groove track and a land track formed alternately, and the beam An information mark group in which a pair of information recording marks that are shifted by a predetermined distance from side to side with respect to the track center of each groove track are combined at the same phase position of each of the plurality of groove tracks included in the spot And a pair of information recording marks that are shifted by a predetermined distance to the left and right with respect to the track center of each land track at the same phase position of each of the plurality of land tracks included in the beam spot.
  • An information mark group is formed by combining.
  • the information mark group is formed on both the groove track and the land track. Therefore, the recording / reproducing apparatus can read the bit data corresponding to the information mark group by irradiating either the groove track or the land track with the guide laser beam.
  • the detection means returns the guide laser light irradiated to the information mark group.
  • a second push-pull signal is further detected from the light, and based on the second push-pull signal, the plurality of guide tracks in which the guide track determined to be the center track by the determining unit is located near the center.
  • Acquisition means for acquiring bit data corresponding to the information mark group formed on each of the recording marks, and at least one of the recording operation and the reproduction operation for the plurality of recording layers based on the bit data acquired by the acquisition means;
  • Recording information reproducing means for performing one of the information recording means, wherein the obtaining means comprises the pair of information recording markers constituting the information mark group. Based on the signal level of the second push-pull signal which varies according to the combination of click, to acquire the bit data.
  • the acquisition means is based on the second push-pull signal obtained from the return light of the guide laser light, and the bit data corresponding to the information mark group (for example, a pair of information constituting the information mark group) Bit data corresponding to the combination of recording marks for use).
  • the recording / reproducing means can perform at least one of a recording operation and a reproducing operation with respect to the plurality of recording layers based on the bit data.
  • the acquisition unit instead of acquiring the bit data corresponding to all the information mark groups irradiated with the guide laser beam, the acquisition unit has the guide track determined to be the center track near the center. Bit data corresponding to the information mark group formed on each of the plurality of guide tracks is selectively acquired. Therefore, the acquisition means is formed on each of a plurality of guide tracks having one guide track as the center track, based on the second push-pull signal obtained from the guide laser beam whose spot center coincides with the other guide tracks. There is little or no risk of acquiring bit data corresponding to one information mark group. Thus, there is little or no risk of the technical problems described above.
  • the acquisition unit preferably uses the bit data based on the change in the signal level of the second push-pull signal according to the combination of the pair of information recording marks constituting the information mark group. Can be acquired.
  • the recording / reproducing method of the present embodiment includes (i-1) a guide layer in which a guide track for tracking is formed, and (i-2) a recording layer including a plurality of recording layers stacked on the guide layer. (Ii) the guide layer is formed with (ii-1) an information mark group formed on each of a plurality of guide tracks adjacent to each other; and (ii-2) the information mark group is formed.
  • a discriminating mark group for discriminating a center track that is a guide track located near the center of the plurality of guide tracks, and (iii) the discriminating mark group is (iii- 1) a pair of discriminating recording marks shifted by a predetermined distance from side to side with respect to the track center of the center track, and (iii-2) the width of each discriminating recording mark is equal to the width of the guide track Includes a pair of discriminating recording marks that are more than doubled
  • the same effects as the various effects that can be enjoyed by the recording / reproducing apparatus of the present embodiment described above can be suitably enjoyed.
  • the recording / reproducing method of the present embodiment may also take various aspects, corresponding to the various aspects that the recording / reproducing apparatus of the present embodiment can take.
  • the recording / reproducing apparatus of the present embodiment includes a detection unit and a determination unit.
  • the recording / reproducing method of this embodiment includes a detection step and discrimination. Therefore, in order to preferably read the information mark group recorded on each of the plurality of guide tracks on the guide layer, the information mark group is positioned near the center of the plurality of guide tracks on which the information mark group is formed. It is possible to perform at least one of a recording operation and a reproducing operation with respect to a recording medium that can appropriately determine the center track.
  • FIG. 1 is a schematic perspective view in which a plurality of layers constituting one optical disk 11 are disassembled at intervals in the stacking direction (vertical direction in FIG. 1) to make each layer easy to see.
  • FIG. 2 is a cross-sectional view showing a cross section of the optical disc 11 together with the irradiation modes of the guide laser beam LB1 and the recording / reproducing laser beam LB2.
  • the optical disc 11 includes a single guide layer 12 and a plurality of (that is, two or more) recording layers 13. That is, the optical disk 11 is a so-called guide layer separation type optical disk.
  • the tracking guide laser beam LB1 focused on the guide layer 12 and the plurality of recording layers 13 are collected.
  • the recording / reproducing laser beam LB2 emitted is simultaneously irradiated from the recording / reproducing apparatus 100.
  • the guide laser beam LB1 and the recording / reproducing laser beam LB2 are simultaneously irradiated from the recording / reproducing apparatus 100.
  • the recording / reproducing laser beam LB2 may be used for tracking (that is, the guide laser beam LB1 may not be used).
  • the optical disk 11 preferably adopts the CLV method.
  • preformat information for example, clock information, address information, recording start timing, etc.
  • Information etc. is recorded in advance.
  • preformat information includes an information mark formed by combining a pair of information recording marks ML1 and MR1 (see FIGS. 3 and 5) that are shifted equidistantly from side to side with respect to the track center. Recorded using group MG1 (see FIGS. 4 and 6).
  • Such an information mark group MG1 is preferably formed in advance on the guide layer 12 (in other words, the guide track TR included in the guide layer 12) when the optical disc 11 is manufactured.
  • the information mark group MG1 in which the pair of information recording marks ML1 and MR1 are combined will be described in detail later with reference to the drawings after FIG.
  • the guide track TR (specifically, a groove track GT and a land track LT described later) is the guide closest to the center of the plurality of guide tracks TR in which the same information mark group MG1 is formed.
  • a discrimination mark group MG2 for discriminating the center track CT which is the track TR is formed.
  • such a discrimination mark group MG2 includes a pair of discrimination recording marks ML2 and MR2 (FIGS. 7 to 8 and FIG. 10) that are shifted equidistant from side to side with respect to the track center of the center track CT. To FIG. 11).
  • Such a discrimination mark group MG2 is preferably formed in advance on the guide layer 12 (in other words, the guide track TR included in the guide layer 12) when the optical disc 11 is manufactured. Note that the discrimination mark group MG2 in which the pair of discrimination recording marks ML2 and MR2 are combined will be described in detail later with reference to FIGS.
  • the guide track TR formed on the guide layer 12 may be a single spiral.
  • the groove track GT is preferably switched to the land track LT in a predetermined region of the guide layer 12.
  • the land track LT is preferably switched to the groove track GT in a predetermined region of the guide layer 12.
  • the guide track TR may be a double spiral in which the groove track GT and the land track LT are separated.
  • the recording / reproducing laser beam LB2 is focused on one desired recording layer 13 to be recorded or reproduced among the plurality of recording layers 13 stacked on the guide layer 12.
  • the recording / reproducing laser beam LB2 is a blue laser beam having a relatively short wavelength as in, for example, BD (Blu-ray Disc: Blu-ray Disc).
  • the guide laser beam LB1 is a red laser beam having a relatively long wavelength as in the case of DVD, for example.
  • the diameter of the beam spot formed on the guide layer 12 by the guide laser beam LB1 is, for example, about several times the diameter of the beam spot formed on the recording layer 13 by the recording / reproducing laser beam LB2.
  • Each of the plurality of recording layers 13 is a recording layer capable of optically recording and reproducing recording information independently. More specifically, each of the plurality of recording layers 13 is composed of, for example, a translucent thin film containing a two-photon absorption material.
  • a two-photon absorption material a fluorescent type using a fluorescent material in which the fluorescence intensity in a region where two-photon absorption occurs is changed, a refractive index changing type using a photorefractive material in which the refractive index is changed by electron localization, etc.
  • photochromic compounds, bis (aralkylidene) cycloalkanone compounds, etc. is promising as refractive index changing type two-photon absorption materials.
  • an optical disk structure using a two-photon absorption material (i) a bulk type in which the entire optical disk 11 is made of a two-photon absorption material, and (ii) a recording layer of a two-photon absorption material and a spacer layer of another transparent material are alternated.
  • the layer structure type has an advantage that focus control can be performed using light reflected at the interface between the recording layer 13 and the spacer layer.
  • the bulk type has an advantage that the manufacturing cost can be suppressed because there are few multilayer film forming steps.
  • Each of the plurality of recording layers 13 may be, for example, a dye material in addition to the above-described two-photon absorption material and phase change material.
  • the guide track TR is not formed in advance in an unrecorded state, and for example, the entire region is a mirror surface or a flat surface without unevenness.
  • the wobbling may be appropriately performed on the groove track GT and the land track LT.
  • a reflective film made of, for example, a light-reflective material is formed on a transparent film as a substrate on which concave and convex grooves are formed, and is further transparent or opaque as a protective film. It may be formed by being filled with an appropriate film. Wobbling may be performed on the side walls of the groove track GT and the land track LT.
  • information mark group MG1 that is, guide track
  • a configuration of a discrimination mark group MG2) in which a pair of discrimination recording marks ML2 and MR2 shifted equidistantly from side to side as a reference will be described.
  • FIG. 3 is a plan view showing the configuration of a pair of information recording marks ML1 and MR1 constituting the information mark group MG1 formed on the groove track GT.
  • FIG. 4 is a plan view showing an aspect in which various types of data (specifically, bit data and synchronization data) are recorded by the information mark group MG1 formed on the groove track GT.
  • the groove track GT is formed with a pair of information recording marks ML1 and MR1 that are shifted equidistant from side to side with respect to the track center of the groove track GT. More specifically, the groove track GT includes (i) an information recording mark ML1 shifted by a predetermined distance to the left side (for example, the left side with respect to the traveling direction of the groove track GT) with respect to the track center of the groove track GT. (Ii) An information recording mark MR1 shifted by a predetermined distance to the right side (for example, right side with respect to the traveling direction of the groove track GT) with respect to the track center of the groove track GT is formed.
  • the information mark group MG1 formed on the groove track GT is composed of such a pair of information recording marks ML1 and MR1.
  • the information mark group MG1 formed on the groove track GT is a pair of information recording marks ML1 and MR1 itself (that is, only one pair of information recording marks ML1 and MR1 are combined.
  • An example of the information mark group MG1 is shown.
  • the information mark group MG1 formed on the groove track GT has a plurality of information recording marks ML1 and MR1.
  • the information mark group MG1 may be combined, or one or more pairs of information recording marks ML1 and MR1 and one or more other recording marks (for example, the center of the information recording mark may be on the track center). Even when the information mark group MG1 is combined with another information recording mark MC1 (see FIG. 4A) or an area where the information recording mark is not formed (see FIG. 6A) positioned at Good.
  • the same information mark group MG1 is formed at the same rotational phase position (in other words, the same rotational angle position) of each of the plurality of groove tracks GT. That is, the same information mark group MG1 is adjacent to each other along a direction (that is, a vertical direction in FIG. 3) orthogonal to the traveling direction of the groove track GT (the direction from the left side to the right side in FIG. 3). Alternatively, it is formed on each of the plurality of groove tracks GT so as to be arranged.
  • FIG. 3 shows three groove tracks GT (that is, a groove track GT with a track number “k-2”, a groove track GT with a track number “k”, and a groove track GT with a track number “k + 2”).
  • An information mark group MG1 in which the information recording mark ML1 and the information recording mark MR1 are arranged in this order along the traveling direction of the groove track GT is formed at the same rotational phase position. ing.
  • the same information mark group MG1 is at the same rotational phase position of each of the plurality of groove tracks GT to be included in the beam spot of the guide laser beam LB1 (that is, the beam spot on the guide layer 12). It is formed.
  • the number of the plurality of groove tracks GT in which the same information mark group MG1 is formed at the same rotational phase position is almost the same as the number of the groove tracks GT included in the beam spot of the guide laser beam LB1.
  • FIG. 3 shows an example in which the number of the plurality of groove tracks GT to be included in the beam spot of the guide laser beam LB1 is “3”. Therefore, FIG.
  • FIG. 3 shows that the same information mark group MG1 (that is, the information recording mark ML1 and the information recording mark MR1 travel in the traveling direction of the groove track GT) at the same rotational phase position of each of the three groove tracks GT.
  • the information mark group MG1) arranged in this order is formed.
  • FIG. 3 shows an example of the information mark group MG1 in which the information recording mark ML1 and the information recording mark MR1 are arranged in this order along the traveling direction of the groove track GT.
  • the information mark group MG1 in which the information recording marks MR1 and the information recording marks ML1 are arranged in this order along the traveling direction of the groove track GT may be used.
  • the location which is a recessed part compared with the periphery is shown by hatching.
  • a portion that is a convex portion compared with the surroundings is indicated by a blank (white). Therefore, in the optical disk 11 of the present embodiment, an example is shown in which the groove track GT becomes a concave portion and the land track LT becomes a convex portion, and the information recording marks ML1 and MR1 become concave portions.
  • the groove track GT may be a convex portion and the land track LT may be a concave portion, and the information recording marks ML1 and MR1 may be convex portions.
  • preformat information for example, clock information, address information, recording start timing information, etc.
  • preformat information is recorded in advance on the guide layer 12 (particularly on the groove track GT) using such an information mark group MG1.
  • bit data constituting a part of the preformat information is recorded in advance on the guide layer 12 using the same information mark group MG formed at the same rotational phase position. ing. Therefore, one preformat information can be obtained by combining (in other words, integrating) bit data obtained from a plurality of different information mark groups MG1 formed at a plurality of locations on the guide layer 12.
  • synchronization data for synchronization when reading bit data constituting at least part of the preformat information is recorded in the guide layer 12.
  • bit data and synchronization data constituting at least a part of the preformat information and arbitrary data may be recorded in advance on the guide layer 12 using the information mark group MG1.
  • the information recording mark MC1 located on the track center, the information recording mark ML1 shifted to the left by a predetermined distance from the track center, and the track center The information recording mark MC1 positioned above and the information recording mark MR1 shifted to the right by a predetermined distance from the track center are arranged in this order along the traveling direction of the groove track GT.
  • the group MG1 may be formed on the groove track GT as the information mark group MG1 constituting the synchronization data.
  • the length of each of the information recording mark MC1, the information recording mark ML1, and the information recording mark MR1 (specifically, the length along the traveling direction of the groove track GT) is shown. , All show “a”.
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 tracing the groove track GT on which the information mark group MG1 shown in FIG. 4A is formed is the information recording mark MC1, Due to the fact that the information recording mark ML1, the information recording mark MC1, and the information recording mark MR1 are read in this order, “0”, “+ (high)”, “0”, and “ ⁇ (low)”.
  • the state where the spot center of the beam spot of the guide laser beam LB1 is shifted to the left from the track center of the groove track GT is assumed to correspond to a state where the polarity of the push-pull signal is negative. Therefore, the synchronization data is read from the push-pull signal whose signal level changes in the order of “0”, “+”, “0”, and “ ⁇ ”.
  • An information mark group MG1 in which an information recording mark ML1 shifted by a predetermined distance and an information recording mark MC1 located on the center of the track are arranged in this order along the traveling direction of the groove track GT is a bit.
  • the information mark group MG1 constituting the data (bit 0) may be formed on the groove track GT.
  • FIG. 4B shows an example in which the lengths of the information recording mark MC1, the information recording mark ML1, and the information recording mark MR1 are all “a”.
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 tracing the groove track GT on which the information mark group MG1 shown in FIG. 4B is formed is the information recording mark MC1, Due to the fact that the information recording mark MR1, the information recording mark ML1, and the information recording mark MC1 are read in this order, they change to “0”, “ ⁇ ”, “+”, and “0”. Therefore, bit data (bit 0) is read from a push-pull signal whose signal level changes in the order of “0”, “ ⁇ ”, “+”, and “0”.
  • An information mark group MG1 in which an information recording mark MR1 shifted by a predetermined distance and an information recording mark MC1 located on the center of the track are arranged in this order along the traveling direction of the groove track GT is a bit.
  • the information mark group MG1 constituting the data (bit 1) may be formed on the groove track GT.
  • FIG. 4C shows an example in which the lengths of the information recording mark MC1, the information recording mark ML1, and the information recording mark MR1 are all “a”.
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 tracing the groove track GT on which the information mark group MG1 shown in FIG. 4C is formed is the information recording mark MC1, Due to the fact that the information recording mark ML1, the information recording mark MR1, and the information recording mark MC1 are read in this order, it changes to “0”, “+”, “ ⁇ ”, and “0”. Therefore, bit data (bit 1) is read from a push-pull signal whose signal level changes in the order of “0”, “+”, “ ⁇ ”, and “0”.
  • the information mark group MG1 shown in FIG. 4 (that is, the information mark group MG1 constituting the synchronization data, and the information mark group MG1 and bit data (bit 1) constituting the bit data (bit 0)) are constituted.
  • the mode of the information mark group MG1) is merely an example. Therefore, the synchronization data, the bit data (bit 0), and the bit data (bit 1) may be configured by using the three types of information mark groups MG1 showing aspects other than those shown in FIG.
  • FIG. 5 is a plan view showing a configuration of a pair of information recording marks ML1 and MR1 constituting the information mark group MG1 formed on the land track LT.
  • FIG. 6 is a plan view showing an aspect in which various types of data (specifically, bit data and synchronization data) are recorded by the information mark group MG1 formed on the land track LT.
  • the land track LT is formed with a pair of information recording marks ML1 and MR1 that are shifted equidistant from side to side with respect to the track center of the land track LT. More specifically, the land track LT includes (i) an information recording mark shifted by a predetermined distance to the left side (for example, the left side with respect to the traveling direction of the land track LT) with respect to the track center of the land track LT. ML and (ii) an information recording mark MR1 shifted by a predetermined distance to the right side (for example, right side with respect to the traveling direction of the land track LT) with respect to the track center of the land track LT.
  • the information mark group MG1 formed on the land track LT is composed of such a pair of information recording marks ML1 and MR1.
  • the information mark group MG1 formed on the land track LT is a pair of information recording marks ML1 and MR1 itself (that is, only one pair of information recording marks ML1 and MR1 are combined.
  • An example of the information mark group MG1 is shown.
  • the information mark group MG1 formed on the land track LT is an information mark group MG1 in which a plurality of pairs of information recording marks ML1 and MR1 are combined.
  • the information mark group MG1 may be combined with MC1 (see FIG. 4A) or an area where the information recording mark is not formed (see FIG. 6A).
  • the same information mark group MG1 is formed at the same rotation phase position (in other words, the same rotation angle position) of each of the plurality of land tracks LT. That is, the same information mark group MG1 is adjacent to each other along a direction orthogonal to the traveling direction of the land track LT (the direction from the left side to the right side in FIG. 5) (that is, the vertical direction in FIG. 5). Alternatively, it is formed on each of the plurality of land tracks LT so as to be arranged.
  • FIG. 5 shows three land tracks LT (ie, a land track LT with a track number “k ⁇ 1”, a land track LT with a track number “k + 1”, and a land track LT with a track number “k + 3”).
  • An information mark group MG1 in which the information recording mark ML1 and the information recording mark MR1 are arranged in this order along the traveling direction of the land track LT is formed at the same rotational phase position. ing.
  • the same information mark group MG1 is at the same rotational phase position of each of the plurality of land tracks LT to be included in the beam spot of the guide laser beam LB1 (that is, the beam spot on the guide layer 12). It is formed.
  • the number of the plurality of land tracks LT in which the same information mark group MG1 is formed at the same rotational phase position is the same as the number of land tracks LT included in the beam spot of the guide laser beam LB1.
  • FIG. 5 shows an example in which the number of the plurality of land tracks LT to be included in the beam spot of the guide laser beam LB1 is “3”. Therefore, FIG.
  • the same information mark group MG1 that is, the information recording mark ML1 and the information recording mark MR1 travel in the traveling direction of the land track LT at the same rotational phase position of each of the three land tracks LT.
  • the information mark group MG1) arrayed in this order along is formed.
  • FIG. 5 shows an example of the information mark group MG1 in which the information recording mark ML1 and the information recording mark MR1 are arranged in this order along the traveling direction of the land track LT.
  • the information mark group MG1 in which the information recording marks MR1 and the information recording marks ML1 are arranged in this order along the traveling direction of the land track LT may be used.
  • preformat information for example, clock information, address information, recording start timing information, etc.
  • preformat information is recorded on the guide layer 12 (particularly, on the land track LT) using such information mark group MG1.
  • bit data constituting a part of the preformat information is recorded in advance on the guide layer 12 using the same information mark group MG1 formed at the same rotational phase position. ing. Therefore, one preformat information can be obtained by combining (in other words, integrating) bit data obtained from a plurality of different information mark groups MG1 formed at a plurality of locations on the guide layer 12.
  • synchronization data for synchronization when reading bit data constituting at least part of the preformat information is recorded in the guide layer 12.
  • bit data and the synchronization data constituting at least part of the preformat information may be recorded on the guide layer 12 using the information mark group MG1.
  • FIG. 6A an area where the information recording mark is not formed, an information recording mark ML1 shifted to the left by a predetermined distance from the track center, and an information recording mark
  • An information mark group MG1 in which an area not formed and an information recording mark MR1 shifted to the right by a predetermined distance with respect to the track center as a reference is arranged in this order along the traveling direction of the land track LT. May be formed on the land track LT as the information mark group MG1 constituting the.
  • FIG. 6A shows an example in which the lengths of the area where the information recording mark is not formed, the information recording mark ML1, and the information recording mark MR1 are all “a”.
  • the unrecorded area, the information recording mark ML1, the area where the information recording mark MR1 is not formed, and the information recording mark MR1 are read in this order, so that “0”, “+”, “0” and It changes to “-”. Therefore, the synchronization data is read from the push-pull signal whose signal level changes in the order of “0”, “+”, “0”, and “ ⁇ ”.
  • the information mark group MG1 to be configured may be formed on the land track LT.
  • FIG. 6B shows an example in which the lengths of the information recording mark ML1 and the information recording mark MR1 are all “a”.
  • the non-recorded area, the information recording mark MR1, the information recording mark ML1, and the area where the information recording mark is not formed are read in this order, so that "0", “-", “+”, and "0" Change. Therefore, bit data (bit 0) is read from a push-pull signal whose signal level changes in the order of “0”, “ ⁇ ”, “+”, and “0”.
  • the information mark group MG1 in which the recording mark for information MR1 and the area where the recording mark for information is not formed are arranged in this order along the traveling direction of the land track LT is the bit data (bit 1).
  • the information mark group MG1 to be configured may be formed on the land track LT.
  • FIG. 6C shows an example in which the lengths of the information recording mark ML1 and the information recording mark MR1 are all “a”.
  • the areas that are not formed, the information recording mark ML1, the information recording mark MR1, and the area where the information recording mark is not formed are read in this order, so that "0", “+”, “-”, and "0" Change. Therefore, bit data indicating bit 1 is read from a push-pull signal whose signal level changes in the order of “0”, “+”, “ ⁇ ”, and “0”.
  • the information mark group MG1 shown in FIG. 6 (that is, the information mark group MG1 constituting the synchronization data, and the information mark group MG1 and bit data (bit 1) constituting the bit data (bit 0)) are constituted.
  • the mode of the information mark group MG1) is merely an example. Therefore, the synchronization data, the bit data (bit 0), and the bit data (bit 1) may be configured by using the three types of information mark groups MG1 showing aspects other than those shown in FIG.
  • the information mark group MG1 formed on the land groove LT is preferably formed simultaneously with the formation of the groove track GT when the optical disc 11 is manufactured. This is because the groove track GT and the information recording marks MR1 and ML1 become concave portions, and therefore, when the optical disc 11 is manufactured, a cutting laser beam is used to cut the position corresponding to the groove track GT and the information mark group MG1. Is done. That is, the cutting laser light is irradiated to the position corresponding to the groove track GT, the position corresponding to the information recording mark MR1, and the position corresponding to the information recording mark ML1.
  • the cutting laser light may not be cut at a position corresponding to the land track LT. That is, the cutting laser light does not have to be irradiated to the position corresponding to the land track LT. Therefore, if the information mark group MG1 formed on the land groove LT is formed simultaneously with the formation of the groove track GT, it is not necessary to irradiate the cutting laser beam at the time of forming the land track LT (in other words, the groove track). It is only necessary to switch the cutting laser light on and off when forming the GT). Therefore, the manufacturing process of the optical disk 11 can be simplified.
  • FIG. 7 is a plan view showing the configuration of the discrimination mark group MG2 for the information mark group MG1 formed on the groove track GT.
  • FIG. 8 is a graph showing the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 that traces on the groove track GT on which the discrimination mark group MG2 is formed.
  • FIG. 9 is a flowchart showing an operation of discriminating the center track CT using the discrimination mark group MG2 shown in FIG.
  • the groove track GT with the track number “k-2”, the groove track GT with the track number “k”, and the groove track GT with the track number “k + 2” are the same.
  • a discrimination mark for discriminating a groove track GT that is, a center track CT) having a track number “k” for the same information mark group MG1 (see FIG. 3) formed at the rotational phase position of The example of composition of group MG2 is shown.
  • the discrimination mark group MG2 includes a pair of discrimination recording marks ML2 and MR2 that are shifted equidistant from side to side with respect to the track center of the center track CT.
  • the discrimination mark group MG2 includes (i) a discrimination recording mark ML2 shifted by a predetermined distance to the left side (for example, the left side with respect to the traveling direction of the center track CT) with respect to the track center of the center track CT.
  • a discriminating recording mark MR2 shifted by a predetermined distance to the right side (for example, right side with respect to the traveling direction of the center track CT) with respect to the track center of the center track CT.
  • the pair of discrimination recording marks ML2 and MR2 may be formed at the same rotational phase position.
  • FIG. 7 shows an example in which the pair of discrimination recording marks ML2 (# 2) and MR2 (# 2) are formed at the same rotational phase position.
  • the pair of determination recording marks ML2 and MR2 may be formed at different rotational phase positions.
  • FIG. 7 shows an example in which the pair of discrimination recording marks ML2 (# 1) and MR2 (# 1) are formed at different rotational phase positions.
  • the discrimination mark group MG2 includes such a pair of discrimination recording marks ML2 and MR2.
  • FIG. 7 shows that the discrimination mark group MG2 formed on the groove track GT has a pair of discrimination recording marks ML2 (# 2) and MR2 (# 2) formed at the same rotational phase position and different rotational phases.
  • An example is shown in which the discrimination mark group MG2 includes a pair of discrimination recording marks ML2 (# 1) and MR2 (# 1) formed at positions.
  • the discrimination mark group MG2 formed on the groove track GT may include only one pair of discrimination recording marks ML2 and MR2, or one or more pairs of discrimination recording marks ML2 and MR2.
  • the determination mark group MG2 may be used.
  • the width of each of the determination recording mark ML2 and the determination recording mark MR2 constituting the determination mark group MG2 is at least twice the width of the guide track TR (or the width of the groove track GT).
  • FIG. 7 shows an example in which the width of each of the determination recording mark ML2 and the determination recording mark MR2 is twice the width of the guide track TR.
  • the width of each of the determination recording mark ML2 and the determination recording mark MR2 may be less than twice the width of the guide track TR and larger than the width of the guide track TR.
  • FIG. 7 shows an example of the discrimination mark group MG1 in which the discrimination recording mark ML2 and the discrimination recording mark MR2 are arranged in this order along the traveling direction of the groove track GT.
  • a discrimination mark group MG2 in which discrimination recording marks MR2 and discrimination recording marks ML2 are arranged in this order along the traveling direction of the groove track GT may be used.
  • FIG. 7 shows an example in which the groove track GT becomes a concave portion and the land track LT becomes a convex portion, and the determination recording marks ML2 and MR2 become concave portions.
  • the groove track GT may be a convex portion and the land track LT may be a concave portion, and the determination recording marks ML2 and MR2 may be convex portions.
  • such a determination mark group MG2 is used to determine the center track CT among a plurality of groove tracks GT on which the same information mark group MG1 is formed. After the center track CT is determined, the center track CT is traced (that is, the center of the spot is located on the center track CT), based on the push-pull signal generated from the return light of the guide laser beam LB1. The preformat information indicated by the mark group MG1 is read.
  • a comparison is made with (where a is a positive real number) and a predetermined second threshold value b (where b is a positive real number smaller than a).
  • the comparison between the signal level of the push-pull signal and the first threshold value a and the second threshold value b is made for each unit (expressed as “mark section” in FIG. 7) in which the recording marks ML2 and MR2 for determination are formed. Done.
  • the mark section is “+ section”.
  • the signal level of the push-pull signal is higher than + a (that is, + a ⁇ signal level)
  • the signal level of the push-pull signal is smaller than ⁇ a (that is, when the signal level ⁇ a)
  • the mark section is determined to be “ ⁇ section”.
  • the signal level of the push-pull signal is a or less and greater than b (that is, b ⁇ signal level ⁇ a)
  • it is determined that the mark section is “+ indefinite section”.
  • the mark interval is “ ⁇ indefinite interval”. It is determined. Further, when the signal level of the push-pull signal is ⁇ b or more and less than b (that is, ⁇ b ⁇ signal level ⁇ b), the mark section is determined to be “0 section”.
  • the first graph in FIG. 8 shows the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT whose track number is “k-2”. ing. This signal level indicates that the first mark section is “+ section”, the second mark section is “ ⁇ section”, and the third mark section is “0 section”.
  • the second graph of FIG. 8 shows the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k”. This signal level indicates that the first mark section is “ ⁇ section”, the second mark section is “+ undefined section and ⁇ undefined section”, and the third mark section is “+ section”. .
  • the tracking laser beam is shifted more than b as shown in FIG. 8 due to the tracking shift of the guide laser beam LB1 or the shift of the mounting position of the photodetector that receives the return light of the guide laser beam LB1.
  • a large signal level or a signal level smaller than ⁇ b may be detected.
  • a small signal level may be detected.
  • the mark interval is “a non-adjacent interval (that is, It is preferable to determine that the section is relatively likely to be the center track CT).
  • the third graph in FIG. 8 shows the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT whose track number is “k + 2”. This signal level indicates that the first mark section is “0 section”, the second mark section is “+ section”, and the third mark section is “ ⁇ section”.
  • step S11 it is first determined whether or not the first mark section is “ ⁇ section” (step S11).
  • step S11 if it is determined that the first mark section is “ ⁇ section” (step S11: Yes), then whether or not the third mark section is “+ section” is determined. Determination is made (step S12).
  • step S12 when it is determined that the third mark section is “+ section” (step S12: Yes), the groove track GT currently being traced by the guide laser beam LB1 is the center track CT. It is determined that there is (step S13).
  • step S12 if it is determined that the third mark section is not the “+ section” (step S12: No), then, is the third mark section a “+ indefinite section”? It is determined whether or not (step S16).
  • step S16 if it is determined that the third mark section is “+ undefined section” (step S16: Yes), the groove track GT currently being traced by the guide laser beam LB1 is the center track CT. (Step S13).
  • step S16 determines whether the third mark section is “+ undefined section” (step S16: No). If it is determined in step S16 that the third mark section is not “+ undefined section” (step S16: No), the groove track GT traced by the guide laser beam LB1 is the center track. It is determined that it is not CT (step S17).
  • step S11 determines whether the first mark section is “ ⁇ section” or not. It is determined whether or not (step S14).
  • step S14 if it is determined that the first mark section is “ ⁇ indefinite section” (step S14: Yes), then whether the second mark section is “a section that is not adjacent”. It is determined whether or not (step S15).
  • step S15 when it is determined that the second mark section is “a section that is not adjacent” (step S15: Yes), the operations after step S12 are performed.
  • step S15 when it is determined that the second mark section is not “a non-adjacent section” (step S15: No), the groove track GT currently being traced by the guide laser beam LB1 is determined. It is determined that the track is not the center track CT (step S17).
  • step S14 when it is determined that the first mark section is not “ ⁇ undefined section” (step S14: No), the groove track GT currently being traced by the guide laser beam LB1 is the center track. It is determined that it is not the track CT (step S17).
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k ⁇ 2” is the “+ section” in the first mark section, and the second mark This indicates that the section is “ ⁇ section” and the third mark section is “0 section”. Therefore, in this case, it is determined that the first mark section is not a ⁇ section (step S11: No), and the first mark section is not a ⁇ indefinite section (step S14: No). Accordingly, it is determined that the groove track GT currently traced by the guide laser beam LB1 (that is, the groove track GT with the track number “k ⁇ 2”) is not the center track CT (step S17).
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k” is the “ ⁇ section” in the first mark section,
  • the mark section is “a section that is not adjacent”, and the third mark section is “+ section”. Therefore, in this case, it is determined that the first mark section is the-section (step S11: Yes) and the third mark section is the + section (step S12: Yes). Therefore, it is determined that the groove track GT currently traced by the guide laser beam LB1 (that is, the groove track GT with the track number “k”) is the center track CT (step S13).
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k + 2” is “0 section” in the first mark section
  • the mark section is “+ section” and the third mark section is “ ⁇ section”. Therefore, in this case, it is determined that the first mark section is not a ⁇ section (step S11: No), and the first mark section is not a ⁇ indefinite section (step S14: No). Therefore, it is determined that the groove track GT currently traced by the guide laser beam LB1 (that is, the groove track GT with the track number “k + 2”) is not the center track CT (step S17).
  • the center track CT is suitably discriminated using the discrimination mark group MG2.
  • the mode of the discrimination mark group MG2 shown in FIGS. 7 and 8 is merely an example. Accordingly, a discrimination mark group MG2 showing a mode other than the mode shown in FIGS. 7 and 8 (that is, a pair of discrimination recording marks ML2 and MR2 formed at the same rotational phase position and different rotational phase positions).
  • the center track CT may be discriminated using an arbitrary discriminating mark group MG2) including at least one of the pair of discriminating recording marks ML2 and MR2.
  • the flowchart shown in FIG. 9 is also changed in accordance with the determination mark group MG2 showing a mode other than the modes shown in FIGS.
  • FIG. 7 shows that the determination recording mark ML2 (# 1), the pair of determination recording marks ML2 (# 2) and MR2 (# 2), and the determination recording mark MR2 (# 1) are continuously (in other words, In this example, the gap is formed without a gap.
  • the discriminating recording mark ML2 (# 1), the pair of discriminating recording marks ML2 (# 2) and MR2 (# 2), and the discriminating recording mark MR2 (# 1) are discretely (in other words, spaced apart). May be formed).
  • FIG. 10 is a plan view showing the configuration of the discrimination mark group MG2 for the information mark group MG1 formed on the land track LT.
  • FIG. 11 is a graph showing the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 that traces on the land track LT on which the discrimination mark group MG2 is formed.
  • FIG. 12 is a flowchart showing an operation of discriminating the center track CT using the discrimination mark group MG2 shown in FIG.
  • the land track LT with the track number “k ⁇ 1”, the land track LT with the track number “k + 1”, and the land track LT with the track number “k + 3” are the same.
  • a discriminating mark for discriminating the land track LT that is, the center track CT
  • the same information mark group MG1 (see FIG. 5) formed at the rotational phase position of The example of composition of group MG2 is shown.
  • the discrimination mark group MG2 formed on the land track LT is equidistant from side to side with respect to the track center of the center track CT, like the discrimination mark group MG2 formed on the groove track GT. It includes a pair of shifted recording marks ML2 and MR2. Accordingly, the detailed description of the features of the discrimination mark group MG2 formed on the land track LT that are the same as those of the discrimination mark group MG2 formed on the groove track GT will be omitted.
  • such a determination mark group MG2 is used to determine the center track CT among a plurality of land tracks LT on which the same information mark group MG1 is formed. After the center track CT is determined, the center track CT is traced (that is, the center of the spot is located on the center track CT), based on the push-pull signal generated from the return light of the guide laser beam LB1. The preformat information indicated by the mark group MG1 is read.
  • Such a comparison between the signal level of the push-pull signal and the first threshold value a and the second threshold value b is performed for each unit (that is, the mark section) in which the discrimination recording marks ML2 and MR2 are formed. That is, as for the discrimination mark group MG2 formed on the land track LT, it is determined what each mark interval is like the discrimination mark group MG2 formed on the groove track GT.
  • the first graph in FIG. 11 shows the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k ⁇ 1”. ing. This signal level indicates that the first mark section is “+ section”, the second mark section is “ ⁇ section”, and the third mark section is “0 section”.
  • the second graph of FIG. 11 shows the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 1”. This signal level indicates that the first mark section is a “ ⁇ section”, the second mark section is a “non-adjacent section”, and the third mark section is a “+ section”.
  • the third graph of FIG. 11 shows the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 3”. This signal level indicates that the first mark section is “0 section”, the second mark section is “+ section”, and the third mark section is “ ⁇ section”.
  • step S21 it is determined whether or not the first mark section is “ ⁇ section” (step S21).
  • step S21 when it is determined that the first mark section is “ ⁇ section” (step S21: Yes), it is subsequently determined whether the third mark section is “+ section” or not. Determination is made (step S22).
  • step S22 when it is determined that the third mark section is “+ section” (step S22: Yes), the land track LT currently traced by the guide laser beam LB1 is the center track CT. It is determined that there is (step S23).
  • step S22 if it is determined that the third mark section is not “+ section” (step S22: No), then, is the third mark section “+ indefinite section”? It is determined whether or not (step S26).
  • step S26 when it is determined that the third mark section is “+ undefined section” (step S26: Yes), the land track LT currently being traced by the guide laser beam LB1 is the center track CT. (Step S23).
  • step S26 if it is determined that the third mark section is not “+ indefinite section” (step S26: No), the land track LT currently being traced by the guide laser beam LB1 is the center. It is determined that it is not the track CT (step S27).
  • step S21 determines whether the first mark section is “ ⁇ section” or not. It is determined whether or not (step S24).
  • step S24 if it is determined that the first mark section is “ ⁇ indefinite section” (step S24: Yes), then whether the second mark section is “non-adjacent section” or not. It is determined whether or not (step S25).
  • step S25 when it is determined that the second mark section is “a section that is not adjacent” (step S25: Yes), the operations in and after step S22 are performed.
  • step S25 if it is determined that the second mark section is not “a non-adjacent section” (step S25: No), the land track LT currently being traced by the guide laser beam LB1 is determined. It is determined that the track is not the center track CT (step S27).
  • step S24 if it is determined that the first mark section is not “ ⁇ indefinite section” (step S24: No), the land track LT traced by the guide laser beam LB1 is the center track. It is determined that it is not CT (step S27).
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k ⁇ 1” is the “+ section” in the first mark section, and the second mark This indicates that the section is “ ⁇ section” and the third mark section is “0 section”. Accordingly, in this case, it is determined that the first mark section is not a ⁇ section (step S21: No), and the first mark section is not a ⁇ indefinite section (step S24: No). Accordingly, it is determined that the land track LT currently traced by the guide laser beam LB1 (that is, the land track LT with the track number “k ⁇ 1”) is not the center track CT (step S27).
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 1” is the “ ⁇ section” in the first mark section,
  • the mark section is “a section that is not adjacent”, and the third mark section is “+ section”. Therefore, in this case, it is determined that the first mark section is the-section (step S21: Yes) and the third mark section is the + section (step S22: Yes). Accordingly, it is determined that the land track LT currently traced by the guide laser beam LB1 (that is, the land track LT with the track number “k + 1”) is the center track CT (step S23).
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 3” is “0 section” in the first mark section
  • the mark section is “+ section”
  • the third mark section is “ ⁇ section”. Accordingly, in this case, it is determined that the first mark section is not a ⁇ section (step S21: No), and the first mark section is not a ⁇ indefinite section (step S24: No). Accordingly, it is determined that the land track LT currently traced by the guide laser beam LB1 (that is, the land track LT with the track number “k + 3”) is not the center track CT (step S27).
  • the center track CT is suitably discriminated using the discrimination mark group MG2.
  • the mode of the discrimination mark group MG2 shown in FIGS. 10 and 11 is merely an example. Accordingly, a discrimination mark group MG2 showing a mode other than the modes shown in FIGS. 10 and 11 (that is, a pair of discrimination recording marks ML2 and MR2 formed at the same rotational phase position and different rotational phase positions).
  • the center track CT may be discriminated using an arbitrary discriminating mark group MG2) including at least one of the pair of discriminating recording marks ML2 and MR2.
  • the flowchart shown in FIG. 12 is also changed in accordance with the determination mark group MG2 showing an aspect other than the aspects shown in FIGS.
  • FIG. 13 is a data structure diagram showing the data structure of the guide layer 12 (and also the recording layer 13).
  • FIG. 14 is a plan view showing an example of the information mark group MG1 and the discrimination mark group MG2 formed in a specific slot.
  • FIG. 15 is a plan view showing an aspect in which a plurality of information mark groups MG1 and a plurality of determination mark groups MG2 are recorded in a plurality of slots.
  • the recording layer 13 is divided into units called ECC blocks. That is, the recording information recorded on the recording layer 13 is recorded in units of ECC blocks.
  • the guide layer 12 is also divided in units of ECC blocks. That is, preformat information (for example, address information, clock information, recording start timing information, etc.) recorded on the guide layer 12 is recorded in units of ECC blocks.
  • One ECC block is subdivided into units of two words.
  • One word is subdivided into units of 40 groups or 43 groups.
  • One group is subdivided into units of 8 slots.
  • One slot has a size corresponding to 21 wobbles.
  • the “wobble” here refers to, for example, a wobble defined in the Blu-ray standard.
  • 3 wobbles corresponding to the header and 3 wobbles corresponding to the footer each correspond to a buffer area for preventing interference with adjacent slots. Accordingly, information of a size corresponding to a maximum of 15 wobbles can be recorded in one slot.
  • a discrimination mark group MG2 for discriminating the center track CT among the three groove tracks GT on which the three types of information mark groups MG1 indicating the three bit data are formed Is formed using 2 out of 15 wobbles. That is, in the example shown in FIG. 8, 3-bit bit data can be recorded in one slot.
  • one discrimination mark is used to discriminate the center track CT among the three groove tracks GT in which each of the three types of information mark groups MG1 representing three bit data is formed.
  • Group MG2 is used. Therefore, after the center track CT is discriminated by the discriminating mark group MG2 shown in FIG. 14, three types of information mark groups MG1 showing the three bit data shown in FIG. 14 are read. In order to determine the center track CT among the three groove tracks GT on which the other information mark groups MG1 formed in the other slots are formed, the other information formed in the other slots The discriminating mark group MG2 is used. That is, in this embodiment, the information mark group MG1 and the discrimination mark group MG2 are associated with each other in slot units. However, the information mark group MG1 and the discrimination mark group MG2 may be associated with other units other than the slot unit.
  • different information data groups MG1 are overlapped at the same rotational phase position of the same groove track GT or the same land track LT. It is configured not to be formed.
  • different discrimination data groups MG2 are configured not to be duplicated at the same rotational phase position of the same groove track GT or the same land track LT.
  • the information mark group MG1 formed at the same rotational phase position of each of the plurality of guide tracks TR centering on the guide track TR having the track number “k” and the information mark group MG1 are associated with each other.
  • the determination mark group MG2 is referred to as a mark group MG (k), and the description will proceed.
  • mark group MG (k) is formed in slot # 1 as shown in FIG.
  • the mark group MG (k) includes not only the groove track GT with the track number “k”, but also the groove track GT with the track number “k ⁇ 2” and the groove track with the track number “k + 2”. It is similarly formed in GT. Therefore, the mark group MG other than the mark group MG (k) is on the guide track TR from the groove track GT with the track number “k ⁇ 2” to the groove track GT with the track number “k + 2”. It is not formed at the position of slot # 1. As a result, the mark group MG (k) and the mark group MG other than the mark group MG (k) are not repeatedly formed at the same rotational phase position on the same guide track TR.
  • the other mark groups MG other than the mark group MG (k) are guided track TR from the groove track GT having the track number “k ⁇ 2” to the groove track GT having the track number “k + 2”. Even above, it may be formed in slots other than slot # 1. That is, in this embodiment, a certain mark group MG (k) and another mark group MG (for example, a mark group MG) formed on the same guide track TR as the guide track TR on which the mark group MG (k) is formed. Group MG (k-4) to mark group MG (k-1) and mark group MG (k + 1) to mark group MG (k + 4)) are preferably formed in separate slots. As a result, the mark group MG (k) and the mark group MG other than the mark group MG (k) are not repeatedly formed at the same rotational phase position on the same guide track TR.
  • MG (k ⁇ 1) is a land track LT with a track number “k-3”, a land track LT with a track number “k ⁇ 1”, and a track number “k + 1”.
  • An example is shown in which it is formed at the position of slot # 8 of the land track LT.
  • FIG. 15 shows that MG (k + 1) is a land track LT with a track number “k ⁇ 1”, a land track LT with a track number “k + 1”, and a land track LT with a track number “k + 3”.
  • An example is shown in which it is formed at the position of slot # 2 of the track LT.
  • FIG. 15 shows that MG (k + 2) is a groove track GT with a track number “k”, a groove track GT with a track number “k + 2”, and a groove track GT with a track number “k + 4”.
  • FIG. 15 shows that MG (k + 3) is a land track LT with a track number “k + 1”, a land track LT with a track number “k + 3”, and a land track LT with a track number “k + 5”.
  • MG (k + 4) is a groove track GT with a track number “k + 2”, a groove track GT with a track number “k + 4”, and a groove track GT with a track number “k + 6”.
  • the groove track GT with the track number “k ⁇ 2” is changed to the groove track GT with the track number “k + 2”.
  • the mark groups MG (k ⁇ 1) to MG (k + 4) in which a part of the recording marks are formed on the guide tracks TR are formed at positions overlapping each other (that is, at the same rotational radius position). It will not be done.
  • the recording / reproducing apparatus 100 determines that the groove track GT (k) is the center track CT based on the determination mark group MG2 included in the mark group MG (k) formed in the slot # 1. Thereafter, the recording / reproducing apparatus 100 reads bit data and the like from the information mark group MG1 included in the mark group MG (k). Thereafter, the recording / reproducing apparatus 100 continues tracing the lube track GT (k).
  • the recording / reproducing apparatus 100 may also read the mark groups MG (2) to MG (8) formed in the slot # 2 to the slot # 8. However, according to the determination mark group MG2 included in the mark groups MG (2) to MG (8) formed in the slot # 2 to the slot # 8, it is determined that the groove track GT (k) is not the center track CT. The Therefore, the recording / reproducing apparatus 100 does not read bit data or the like from the information mark group MG1 included in the mark groups MG (2) to MG (8) formed in the slot # 2 to the slot # 8. That is, the recording / reproducing apparatus 100 is associated with the determination mark group MG2 only when the currently tracked guide track TR is determined to be the center track CT (in other words, included in the same slot). The bit data indicated by the information mark group MG1 is read.
  • the recording / reproducing apparatus 100 traces the groove track GT (k) to obtain bit data or the like from the information mark group MG1 included in the mark group MG (k) formed in the slot # 1. Can be read.
  • the recording / reproducing apparatus 100 is formed in the slot # 1 even if the groove track GT (k-2) or the groove track GT (k + 2) different from the groove track GT (k) is traced.
  • the information mark group MG1 included in the mark group MG (k) can be read.
  • the recording / reproducing apparatus 100 may erroneously recognize the address information of the currently traced location. That is, the recording / reproducing apparatus 100 may erroneously recognize that the groove track GT (k) is being traced although the groove track GT (k + 2) is originally being traced. As a result, there is a possibility that an appropriate recording operation and an appropriate reproduction operation are not performed. However, in this embodiment, the recording / reproducing apparatus 100 is formed in the slot # 1 even if the groove track GT (k-2) or the groove track GT (k + 2) different from the groove track GT (k) is traced. The information mark group MG1 included in the mark group MG (k) is not read. Therefore, the technical problem which arises with the optical disk of a comparative example does not arise.
  • the shift amounts of the information recording marks ML1 and MR1 from the track center may be unified in all the information mark groups MG1, or may be different for each information mark group MG1.
  • the shift amount from the track center of the information recording marks ML1 and MR1 constituting the information mark group MG1 included in the mark group MG (k) is the mark group MG (k).
  • the shift amounts from the track center of the information recording marks ML1 and MR1 constituting the information mark group MG1 included in the other mark group MG may be the same or different.
  • the shift amounts from the track center of the information recording marks ML1 and MR1 constituting the information mark group MG1 are at least unified within the same information mark group MG1.
  • the shift amount from the track center of the information recording marks ML1 and MR1 constituting the information mark group MG1 included in the mark group MG (k) is at least the information mark group MG1 included in the mark group MG (k). It is sufficient if they are unified within the company.
  • the shift amounts of the discrimination recording marks ML2 and MR2 from the center of the center track CT may be unified in all discrimination mark groups MG2, or may be different for each discrimination mark group MG2.
  • the shift amount from the track center of the center track CT of the discrimination recording marks ML2 and MR2 constituting the discrimination mark group MG2 included in the mark group MG (k) is expressed as follows.
  • the shift amount from the track center of the center track CT of the discrimination recording marks ML2 and MR2 constituting the discrimination mark group MG2 included in the other mark group MG other than MG (k) may be the same or different. It may be.
  • the shift amounts of the discrimination recording marks ML2 and MR2 from the track center of the center track CT may be different within the same discrimination mark group MG2.
  • the shift amount from the track center of the center track CT of the first discrimination recording mark ML2 and MR2 constituting the discrimination mark group MG2 included in the mark group MG (k) is
  • the shift amount from the track center of the center track CT of the second discrimination recording marks ML2 and MR2 constituting the discrimination mark group MG2 included in the mark group MG (k) may be different.
  • the beam spot of the guide laser beam LB1 is derived from the return beam of the guide laser beam LB1 that traces on the guide track TR. And a push-pull signal corresponding to the positional relationship between the center of the guide track TR and the track center of the guide track TR. As a result, tracking control based on the push-pull signal is performed.
  • the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 traced on the guide track TR on which the information mark group MG1 is formed is the information recording mark ML1 constituting the information mark group MG1.
  • the signal level of the push-pull signal depends on the positional relationship between the spot center of the beam spot of the guide laser beam LB1 and the information recording marks ML1 and MR2 constituting the information mark group MG1. fluctuate.
  • the information mark group MG1 is an information mark group MG1 in which a pair of information recording marks ML1 and MR1 that are shifted equidistant from the center of the track to the left and right are combined, the average of the signal level fluctuation of the push-pull signal is averaged.
  • the value (in other words, the integral value) becomes zero. Therefore, even if the information mark group MG1 is formed on the guide track TR, the information mark group MG1 has a large adverse effect on tracking control based on the push-pull signal (for example, normal tracking control cannot be performed). Little or no adverse effects). Accordingly, even if the information mark group MG1 is formed on the guide track TR, suitable tracking control is performed in substantially the same manner as when the information mark group MG1 is not formed on the guide track TR.
  • various data are read from the fluctuation of the signal level of the push-pull signal. That is, in this embodiment, the information mark group MG1 in which the pair of information recording marks ML1 and MR1 are combined is formed on the guide layer 12, thereby recording various data read using the push-pull signal. Can do. In other words, in this embodiment, the information mark group MG1 in which the pair of information recording marks ML1 and MR1 are combined is formed on the guide layer 12, and various data that does not need to be read using the RF signal can be obtained from the guide layer. 12 can be recorded.
  • the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 that traces on the guide track TR on which the discrimination mark group MG2 is formed is the discrimination recording mark ML2 that constitutes the discrimination mark group MG2. And fluctuate according to the MR2 pattern (see, for example, FIGS. 8 and 11). That is, in the present embodiment, the signal level of the push-pull signal depends on the positional relationship between the spot center of the beam spot of the guide laser beam LB1 and the discrimination recording marks ML2 and ML2 constituting the discrimination mark group MG2. fluctuate.
  • the discrimination mark group MG2 is a discrimination mark group MG2 in which a pair of discrimination recording marks ML2 and MR2 that are shifted equidistant from the center of the center track CT to the left and right are combined, the signal level of the push-pull signal The average value of the fluctuations (in other words, the integral value) becomes zero. Therefore, even if the discrimination mark group MG2 is formed on the guide track TR, the discrimination mark group MG2 has a large adverse effect on tracking control based on the push-pull signal (for example, normal tracking control cannot be performed). Little or no adverse effects). Therefore, even if the discrimination mark group MG2 is formed on the guide track TR, suitable tracking control is performed in substantially the same manner as when the discrimination mark group MG2 is not formed on the guide track TR.
  • the discrimination of the center track CT using the push-pull signal is realized by forming the discrimination mark group MG2 in which the pair of discrimination recording marks ML2 and MR2 are combined on the guide layer 12. be able to.
  • the discrimination of the center track CT is realized without using the RF signal by forming the discrimination mark group MG2 in which the pair of discrimination recording marks ML2 and MR2 are combined on the guide layer 12. can do.
  • FIG. 16 is a graph showing the relationship between the depth of the concave portion of the groove track GT (that is, the relative depth of the groove track GT with respect to the land track LT) and the signal levels of the push-pull signal and the RF signal.
  • the signal level of the push-pull signal used for tracking control is best when the depth of the groove track GT is ⁇ / 8n (that is, ⁇ ⁇ (8 ⁇ n)).
  • the signal level of the RF signal that is not used for tracking control is best when the depth of the groove track GT is ⁇ / 4n (that is, ⁇ ⁇ (4 ⁇ n)). If a mark group that needs to be read using an RF signal is formed on the guide layer 12, not only the signal level of the push-pull signal (in other words, signal characteristics) but also the signal level of the RF signal (signal (Characteristics) must also be considered.
  • the information mark group MG1 and the discrimination mark group MG2 that can be read using a push-pull signal originally used for tracking control are recorded on the guide layer 12. Therefore, it is only necessary to consider the signal level (in other words, signal characteristics) of the push-pull signal. In other words, the signal level (signal characteristics) of the RF signal need not be considered.
  • the depth of the groove track GT (and the depths of the information recording marks ML1, MR1 and MC1, and the recording marks ML2 and MR2 for determination) is set to be less than ⁇ / 6n. Also good.
  • tracking control is suitably performed and the information mark group MG1 and the discrimination mark group MG2 are preferably read.
  • the depth of the groove track GT (further, the depth of the information recording marks ML1, MR1, and MC1, and the determination recording marks ML2 and MR2) may be set to less than ⁇ / 8n.
  • the signal characteristics of the push-pull signal are optimized, so that tracking control is performed more suitably, and the information mark group MG1 and the discrimination mark group MG2 are more suitably read.
  • the same information mark group MG1 is formed at the same rotational phase position of each of the plurality of groove tracks GT.
  • the same information mark group MG1 is formed at the same rotational phase position of each of the plurality of land tracks LT. Therefore, the dependence of the guide laser beam LB1 on the focus deviation (focus offset) is weakened (specifically, the preformat information indicated by the information mark group MG1 is preferably used even when the focus deviation increases). Read).
  • FIG. 17 is a plan view showing a comparative example in which the information mark group MG1 is formed on a single groove track GT.
  • FIGS. 19A to 19C are plan views showing the positional relationship between the beam spot of the guide laser beam LB1 on the guide layer 12, the groove track GT, and the pair of information recording marks ML1 and MR1.
  • the amplitude of the push-pull signal when the shift amounts from the track center of the pair of information recording marks ML1 and MR1 constituting the information mark group MG1 are set to four types of 100 nm, 220 nm, 320 nm, and 640 nm are as follows. As shown in FIG. As shown in FIG. 18, in the comparative example in which the information mark group MG1 is formed on a single groove track GT, as the focus deviation increases (for example, in the negative direction in FIG. 18, the push increases). It can be seen that the amplitude of the pull signal is small.
  • the same information mark group MG1 is formed at the same rotational phase position of each of the plurality of groove tracks GT (or the plurality of land tracks LT).
  • the amplitude is substantially the same as the amplitude of the push-pull signal obtained with the tracking servo open. That is, the dependency of the push-pull signal on the focus deviation in this embodiment is substantially the same as the dependency of the push-pull signal amplitude on the focus deviation obtained with the tracking servo open.
  • tracking control is suitably performed, and preformat information recorded on the guide layer 12 is suitably read using the information mark group MG1.
  • the state of the beam spot of the guide laser beam LB1 (see the state A1 in FIG. 19A) when the information recording mark MR1 shifted to the right with respect to the track center is being traced is determined by the tracking servo. It is substantially the same as the state of the beam spot of the guide laser beam LB1 (see state B1 in FIG. 19B) shifted to the left side from the track center in the open state (shifted by about 270 ° in phase). .
  • the tracking servo is opened in the state of the beam spot of the guide laser beam LB1 (see the state A2 in FIG. 19A) when tracing the information recording mark MR1 shifted to the left with respect to the track center.
  • the techniques disclosed in the prior arts 3 and 6 to 11 described above are all formed on a single recording track in order to record a single data on a single recording track as shown in FIG. It just shifts the recorded pit or wobble to the left or right.
  • the techniques disclosed in the above-described prior arts 3 and 6 to 11 do not record the same data at the same rotational phase position of a plurality of recording tracks (in other words, pits or wobbles indicating the same data are not recorded). This is different from the present embodiment in that it is not formed.
  • the width of each of the discrimination recording mark ML2 and the discrimination recording mark MR2 is twice or more the width of the guide track TR. For this reason, in the discrimination mark group MG2 as well as the information mark group MG1, the dependency of the guide laser beam LB1 on the focus deviation (focus offset) is weakened (specifically, when the focus deviation increases). Even in such a case, the discrimination mark group MG2 can be read suitably).
  • the information mark group MG1 is formed on both the groove track GT and the land track LT. Therefore, the size of the preformat information that can be recorded on the guide layer 12 can be increased as compared with the optical disc in which the information mark group MG1 is formed only on one of the groove track GT and the land track LT. Furthermore, this makes it easier to read the preformat information recorded on the guide layer 12 as compared with an optical disc in which the information mark group MG1 is formed on only one of the groove track GT and the land track LT.
  • the discrimination mark group MG2 is formed on both the groove track GT and the land track LT. For this reason, it is determined whether or not the center track CT is for both the groove track GT and the land track LT as compared with the optical disc in which the discrimination mark group MG2 is formed only on one of the groove track GT and the land track LT. A determination is made. Therefore, even when the information mark group MG1 is formed on both the groove track GT and the land track LT, the information mark group MG1 is preferably read.
  • the information mark group MG1 constituting the synchronization data includes the information recording mark MC1 located on the track center in addition to the pair of information recording marks ML1 and MR1. .
  • the reference value for example, zero level
  • the signal level of the push-pull signal varies according to the pair of information recording marks ML1 and MR1. It can be suitably recognized.
  • FIG. 20 is a graph showing a push-pull signal obtained from the information mark group MG1 constituting the synchronization data including the pair of information recording marks ML1 and MR1 and the information recording mark MC1 located on the track center.
  • the push-pull signal corresponding to the pair of information recording marks ML1 and MR1 is used by using a so-called default zero level. Signal level fluctuations are preferably recognized.
  • the so-called default zero is obtained.
  • the signal level of the push-pull signal corresponding to the information recording mark ML1 and the signal level of the push-pull signal corresponding to the information recording mark MR1 are different from each other. As a result, the reliability of reading the information recording marks ML1 and MR1 based on the push-pull signal may deteriorate.
  • the signal of the push-pull signal is used by using the signal level of the push-pull signal corresponding to the information recording mark MC1 located on the track center.
  • the level reference value can be adjusted. Therefore, even if the reference value (for example, zero level) of the signal level of the push-pull signal varies, it is preferable to vary the signal level of the push-pull signal according to the pair of information recording marks ML1 and MR1. Can be recognized.
  • FIG. 21 the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 tracing on the groove track GT on which the discrimination mark group MG2 of the first modification is formed is formed on the groove track GT. It is a graph shown in association with the configuration of the discrimination mark group MG2 of the first modification.
  • FIG. 22 is a flowchart showing an operation of discriminating the center track CT using the discrimination mark group MG2 of the first modification shown in FIG.
  • the discrimination mark group MG2 formed on the groove track GT includes only one pair of discrimination recording marks ML2 and MR2 formed at different rotational phase positions. On the other hand, it does not include the pair of discrimination recording marks ML2 and MR2 formed at the same rotational phase position. That is, in the first modification, the discrimination mark group MG2 is compared with the discrimination mark group MG2 (see FIGS. 7 and 8) described above, and the discrimination recording mark ML2 (# 1) corresponding to the first mark section. ) And the third mark section, and a pair of determination recording marks ML2 (# 2) and MR2 (# 2) corresponding to the second mark section. It differs in that it does not contain.
  • the level indicates that the first mark section is “+ section” and the third mark section is “0 section”.
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k” is the first level.
  • the mark section is “ ⁇ section” and the third mark section is “+ section”.
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k + 2” is the first level.
  • the mark section is “0 section” and the third mark section is “ ⁇ section”.
  • the first mark section is a “ ⁇ section”. It is determined whether or not (step S11).
  • step S11 if it is determined that the first mark section is “ ⁇ section” (step S11: Yes), then whether or not the third mark section is “+ section” is determined. Determination is made (step S12).
  • step S12 when it is determined that the third mark section is “+ section” (step S12: Yes), the groove track GT currently being traced by the guide laser beam LB1 is the center track CT. It is determined that there is (step S13).
  • step S12 determines whether the third mark section is the “+ section” (step S12: No). If it is determined in step S12 that the third mark section is not the “+ section” (step S12: No), the groove track GT currently being traced by the guide laser beam LB1 is the center track. It is determined that it is not CT (step S17).
  • step S11 if it is determined that the first mark section is not the “ ⁇ section” (step S11: No), the groove track GT currently being traced by the guide laser beam LB1 is the center track. It is determined that it is not CT (step S17).
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k-2” is the “+ interval” in the first mark interval and the third mark This indicates that the section is “0 section”. Therefore, in this case, it is determined that the first mark section is not the ⁇ section (step S11: No). Accordingly, it is determined that the groove track GT currently traced by the guide laser beam LB1 (that is, the groove track GT with the track number “k ⁇ 2”) is not the center track CT (step S17).
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k” is the “ ⁇ section” in the first mark section and the third level. It indicates that the mark section is “+ section”. Therefore, in this case, it is determined that the first mark section is the-section (step S11: Yes) and the third mark section is the + section (step S12: Yes). Therefore, it is determined that the groove track GT currently traced by the guide laser beam LB1 (that is, the groove track GT with the track number “k”) is the center track CT (step S13).
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k + 2” is the “0 section” in the first mark section and the third level. It indicates that the marked section is “ ⁇ section”. Therefore, in this case, it is determined that the first mark section is not the ⁇ section (step S11: No). Therefore, it is determined that the groove track GT currently traced by the guide laser beam LB1 (that is, the groove track GT with the track number “k + 2”) is not the center track CT (step S17).
  • the center track CT is suitably discriminated using the discrimination mark group MG2.
  • the groove track GT traced by the guide laser beam LB1 is centered using only a pair of determination recording marks ML2 and MR2 (that is, only two determination recording marks ML2 and MR2). It is determined whether or not the track CT. For this reason, the size (for example, the length along the traveling direction of the groove track GT) of the region where the discrimination mark group MG2 is formed can be relatively shortened.
  • the determination mark group MG2 is formed so as to fit on the five guide tracks TR (that is, from the guide track TR with the track number k-2 to the guide track TR with the track number k + 2). can do. Therefore, when different determination mark groups MG are formed at the same rotational phase position of different guide tracks TR, the interval between the different determination mark groups MG can be relatively narrowed.
  • an operation for determining whether or not the groove track GT traced by the guide laser beam LB1 is the center track CT is relatively simplified.
  • FIG. 22 the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 tracing on the land track LT on which the discrimination mark group MG2 of the second modification is formed is formed on the land track LT. It is a graph shown in association with the configuration of the discrimination mark group MG2 of the second modification.
  • FIG. 24 is a flowchart showing an operation of discriminating the center track CT using the discrimination mark group MG2 of the second modification shown in FIG.
  • the discrimination mark group MG2 formed on the land track LT includes only one pair of discrimination recording marks ML2 and MR2 formed at different rotational phase positions. On the other hand, it does not include the pair of discrimination recording marks ML2 and MR2 formed at the same rotational phase position. That is, in the second modification, the discrimination mark group MG2 is compared with the discrimination mark group MG2 (see FIGS. 10 and 11) described above, and the discrimination recording mark ML2 (# 1) corresponding to the first mark section. ) And the third mark section, and a pair of determination recording marks ML2 (# 2) and MR2 (# 2) corresponding to the second mark section. It differs in that it does not contain.
  • the level indicates that the first mark section is “+ section” and the third mark section is “0 section”.
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 1” is the first level.
  • the mark section is “ ⁇ section” and the third mark section is “+ section”.
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 3” is the first level.
  • the mark section is “0 section” and the third mark section is “ ⁇ section”.
  • the first mark section is a “ ⁇ section”. Is determined (step S21).
  • step S21 when it is determined that the first mark section is “ ⁇ section” (step S21: Yes), it is subsequently determined whether the third mark section is “+ section” or not. Determination is made (step S22).
  • step S22 when it is determined that the third mark section is “+ section” (step S22: Yes), the land track LT currently traced by the guide laser beam LB1 is the center track CT. It is determined that there is (step S23).
  • step S22 determines whether the third mark section is the “+ section” (step S22: No). If it is determined that the third mark section is not the “+ section” (step S22: No), the land track LT currently being traced by the guide laser beam LB1 is the center track. It is determined that it is not CT (step S27).
  • step S21 if it is determined that the first mark section is not the “ ⁇ section” (step S21: No), the land track LT currently traced by the guide laser beam LB1 is the center track. It is determined that it is not CT (step S27).
  • step S21 The signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT whose track number is “k ⁇ 1” is the first mark section is “+ section” and the third mark This indicates that the section is “0 section”. Therefore, in this case, it is determined that the first mark section is not the ⁇ section (step S21: No). Accordingly, it is determined that the land track LT traced by the guide laser beam LB1 (that is, the land track LT with the track number “k ⁇ 1”) is not the center track CT (step S27).
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 1” is the “ ⁇ section” in the first mark section and the third level. It indicates that the mark section is “+ section”. Therefore, in this case, it is determined that the first mark section is the-section (step S21: Yes) and the third mark section is the + section (step S22: Yes). Accordingly, it is determined that the land track LT traced by the guide laser beam LB1 (that is, the land track LT with the track number “k + 1”) is the center track CT (step S23).
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 3” is “0 section” in the first mark section and the third level. It indicates that the marked section is “ ⁇ section”. Therefore, in this case, it is determined that the first mark section is not the ⁇ section (step S21: No). Accordingly, it is determined that the land track LT traced by the guide laser beam LB1 (that is, the land track LT with the track number “k + 3”) is not the center track CT (step S27).
  • the center track CT is suitably discriminated using the discrimination mark group MG2.
  • the various effects which can be enjoyed in the 1st modification can be enjoyed suitably.
  • FIGS. 25 and 26 the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 tracing on the land track LT on which the discrimination mark group MG2 of the third modification is formed is formed on the land track LT. It is a graph shown in association with the configuration of the discrimination mark group MG2 of the third modification.
  • FIG. 26 is a flowchart showing an operation of discriminating the center track CT using the discrimination mark group MG2 of the third modification shown in FIG.
  • the discrimination mark group MG2 formed on the land track LT includes a plurality of a pair of discrimination recording marks ML2 and MR2 formed at different rotational phase positions.
  • the discrimination mark group MG2 includes a pair of discrimination recording marks ML2 (# 1) and MR2 (# 1) formed at different rotational phase positions and a pair of discrimination formed at different rotational phase positions. Recording marks ML2 (# 2) and MR2 (# 2).
  • the discrimination mark group MG2 may include a pair of discrimination recording marks ML2 and MR2 formed at the same rotational phase position.
  • the mark section in which the discrimination recording marks ML2 and MR2 are not included in the beam spot may be handled as being reliably determined as “0 section”. Further, the mark section in which the discrimination recording marks ML2 and MR2 having a width that is three times or more the width of the guide track TR are included in the beam spot is reliably determined to be the “+ section” or the “ ⁇ section”. It may be handled as a thing.
  • the mark section in which the recording marks ML2 and MR2 for determination having a width that is less than or equal to twice (or less than three times) the width of the guide track TR are included in the beam spot is “+ section” or “ It becomes easy to determine that it is “+ undefined section”, “ ⁇ section” or “ ⁇ undefined section”. Accordingly, two or more mark sections on each land track LT need to be recorded for determination in order to be determined as “0 section”, “+ section”, or “ ⁇ section” in two or more mark sections.
  • a mark group MG2 may be formed.
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k ⁇ 1”. Is as follows. First, in the first mark section, since the recording marks ML2 and MR2 for determination are not included in the beam spot, it is determined that the first mark section is “0 section”. In the second mark section, the beam spot includes the determination recording mark ML2 (# 1) having a width that is twice the width of the guide track TR. Therefore, the second mark section is “+ indefinite section (however, In some cases, it may be determined that it is “+ section)”.
  • the third mark section only a part of the determination recording mark MR2 (# 2) having a width that is three times the width of the guide track TR is included in the beam spot (that is, the beam spot is substantially included in the beam spot. Since the determination recording mark MR2 (# 2) having a width that is twice the width of the guide track TR is included), it is determined that the third mark section is “ ⁇ undefined section” or “+ undefined section”. There is a risk of being.
  • the recording mark ML2 (# 2) for determination having a width that is three times the width of the guide track TR is included in the beam spot, so that the fourth mark section is “+ section”. Determined. Therefore, according to the example shown in FIG. 25, when the land track LT having the track number “k ⁇ 1” is traced, the “0 section”, “+ section” in the first mark section and the fourth mark section. Is determined.
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 1” is as follows. It becomes like this.
  • the recording mark MR2 (# 1) for determination having a width that is twice the width of the guide track TR is included in the beam spot. Therefore, the first mark section is “+ undefined section ( However, in some cases, it may be determined that it is “+ section)”.
  • the recording spot ML2 (# 1) having a width that is twice the width of the guide track TR is included in the beam spot.
  • the second mark section is “ ⁇ indefinite section (however, In some cases, it may be determined as “-section)”.
  • the recording mark MR2 (# 2) for determination having a width that is three times the width of the guide track TR is included in the beam spot, and therefore the third mark section is “+ section”. Determined.
  • the recording mark ML2 (# 2) for determination having a width that is three times the width of the guide track TR is included in the beam spot, so that the fourth mark section is “ ⁇ section”. Determined. Therefore, according to the example shown in FIG. 25, when the land track LT having the track number “k + 1” is traced, the “+ section” and “ ⁇ section” in the third mark section and the fourth mark section Determined.
  • the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 3” is as follows. It becomes like this. First, since the first mark section includes the determination recording mark MR2 (# 1) having a width that is twice the width of the guide track TR in the beam spot, the first mark section is “ ⁇ indefinite section ( However, in some cases, it may be determined as “-section)”. In the second mark section, since the recording marks ML2 and MR2 for determination are not included in the beam spot, it is determined that the second mark section is “0 section”.
  • the recording mark MR2 (# 2) for determination having a width that is three times the width of the guide track TR is included in the beam spot, so that the third mark section is “ ⁇ section”. Determined.
  • the beam spot includes only a part of the determination recording mark ML2 (# 2) having a width that is three times the width of the guide track TR. There is a risk of being determined to be “section” or “+ indefinite section”. Therefore, according to the example shown in FIG. 25, when the land track LT having the track number “k + 3” is traced, “0 section” and “ ⁇ section” are displayed in the second mark section and the third mark section. Determined.
  • the first mark section is “0 section” as shown in FIG. Is determined (step S31).
  • step S31 when it is determined that the first mark section is “0 section” (step S31: Yes), the land track LT currently traced by the guide laser beam LB1 is not the center track CT. Is determined (step S36).
  • step S31 determines whether or not the second mark section is “0 section”. If it is determined in step S31 that the first mark section is not “0 section” (step S31: No), it is determined whether or not the second mark section is “0 section”. (Step S32).
  • step S32 when it is determined that the second mark section is “0 section” (step S32: Yes), the land track LT currently traced by the guide laser beam LB1 is not the center track CT. Is determined (step S36).
  • step S32 when it is determined that the second mark section is not “0 section” (step S32: No), it is determined whether or not the third mark section is “+ section”. (Step S33).
  • step S33 if it is determined that the third mark section is not “+ section” (step S33: No), the land track LT currently being traced by the guide laser beam LB1 is not the center track CT. A determination is made (step S36).
  • step S33 determines whether or not the fourth mark section is “ ⁇ section” is determined. Determination is made (step S34).
  • step S34 when it is determined that the fourth mark section is not “ ⁇ section” (step S34: No), the land track LT currently being traced by the guide laser beam LB1 is not the center track CT. A determination is made (step S36).
  • step S34 when it is determined that the fourth mark section is “ ⁇ section” (step S34: Yes), the land track LT currently being traced by the guide laser beam LB1 is the center. It is determined that the track is a CT (step S35).
  • the center track CT is suitably discriminated using the discrimination mark group MG2.
  • the various effects which can be enjoyed in the 1st modification can be enjoyed suitably.
  • the center track CT can be determined using two or more mark sections that are reliably determined to be “0 section”, “+ section”, or “ ⁇ section”. Accordingly, it is possible to relatively improve the accuracy of discrimination of the center track CT.
  • the mode of the discrimination mark group MG2 shown in FIG. 25 is merely an example. Therefore, as long as each land track LT is traced and determined to be “0 section”, “+ section” or “ ⁇ section” in two or more mark sections, what kind of mark group MG2 is used for determination You may have an aspect. In this case, as a matter of course, it is preferable that the flowchart shown in FIG. 26 is also changed in accordance with the determination mark group MG2 showing an aspect other than the aspect shown in FIG.
  • the determination mark group MG2 formed on the land track LT is described.
  • FIG. 27 is a plan view showing a configuration of the discrimination mark group MG2 of the fourth modified example formed on the land track LT.
  • FIG. 28 is a flowchart showing an operation of discriminating the center track CT using the discrimination mark group MG2 of the fourth modified example shown in FIG.
  • the discrimination mark group MG2 formed in the same slot has a pair of discrimination recording marks ML2 shifted equidistantly from side to side with respect to the track center of each land track LT. And MR2. Specifically, the discrimination mark group MG2 is (i) shifted equidistantly from side to side with respect to the track center of the land track LT having the track number “k + 3” and different rotational phase positions (first and second marks).
  • the land track LT currently being traced using the pair of discrimination recording marks ML2 (# 1) and MR2 (# 1) formed in the first and second mark sections is the center track. It is determined whether or not the land track LT is located outside the CT (that is, adjacent to the outside of the center track CT). Specifically, as shown in FIG. 28, the first mark section is determined to be “ ⁇ section” (step S41: Yes), and the second mark section is determined to be “+ section” (step In the case of S42: Yes), it is determined that the currently tracked land track LT is a land track LT located outside the center track CT (step S47).
  • the land track LT currently being traced is determined using the pair of determination recording marks ML2 (# 2) and MR2 (# 2) formed in the third and fourth mark sections. It is determined whether or not the center track CT. Specifically, as shown in FIG. 28, it is determined that the third mark section is “ ⁇ section” (step S43: Yes) and the fourth mark section is determined to be “+ section” (step S43). S44: Yes), it is determined that the currently tracked land track LT is the center track CT (step S48).
  • the land track LT currently being traced is determined using a pair of determination recording marks ML2 (# 3) and MR2 (# 3) formed in the fifth and sixth mark sections. It is determined whether or not the land track LT is located inside the center track CT (that is, adjacent to the inside of the center track CT). Specifically, as shown in FIG. 28, it is determined that the fifth mark section is “ ⁇ section” (step S45: Yes), and the sixth mark section is determined to be “+ section” (step S45). In the case of S46: Yes), it is determined that the currently tracked land track LT is the land track LT located inside the center track CT (step S49).
  • the center track CT is suitably discriminated using the discrimination mark group MG2.
  • various effects that can be enjoyed in the first modification can be suitably enjoyed.
  • the discrimination mark group MG2 shown in FIG. 27 includes (i) a pair of discrimination recording marks ML2 (# 1) and MR2 (# 3) that are shifted equidistant from side to side with respect to the track center of the center track CT. And (ii) a pair of discriminating recording marks ML2 (# 3) and MR2 (# 1) that are shifted equidistantly with respect to the center of the track of the center track CT, and (iii) the track center of the center track CT It can be said that it includes a pair of discriminating recording marks ML2 (# 2) and MR2 (# 2) that are shifted equidistantly to the left and right with reference to.
  • the discrimination mark group MG2 of the fourth modified example also includes a plurality of a pair of discrimination recording marks ML2 and MR2 shifted equidistantly to the left and right with respect to the track center of the center track CT.
  • FIG. 29 is a block diagram showing the configuration of the recording / reproducing apparatus 100 of the present embodiment.
  • the recording / reproducing apparatus 100 includes a disk drive 101 and a host computer 201.
  • the disk drive 101 includes an optical pickup (PU) 102, a signal recording / reproducing unit 103, a spindle motor 104, a bus 106, a CPU 111, a memory 112, and a data input / output control unit 113.
  • PU optical pickup
  • the guide laser beam LB1 is transmitted from the optical pickup 102 via the objective lens 102L (see FIG. 2) of the optical pickup 102. Further, the recording / reproducing laser beam LB2 is irradiated.
  • the host computer 201 includes an operation / display control unit 202, an operation button 203, a display panel 204, a bus 206, a CPU 211, a memory 212, and a data input / output control unit 213.
  • an operation / display control unit 202 When a recording operation on the optical disc 11 (particularly, a recording operation on the desired recording layer 13) is performed, data to be recorded on the desired recording layer 13 is input from the data input / output control unit 213.
  • a reproducing operation for the optical disc 11 particularly, a reproducing operation for a desired recording layer 13
  • the reproduced data is output from the data input / output control unit 213.
  • the optical pickup 102 includes a red semiconductor laser light source that emits a guide laser beam LB1, a blue semiconductor laser light source that emits a recording / reproducing laser beam LB2, and a combining / separating optical system including an objective lens 102L, a prism, a mirror, and the like.
  • the optical pickup 102 irradiates the guide laser beam LB1 and the recording / reproducing laser beam LB2 coaxially and with different focus (see FIGS. 1 and 2) through a common objective lens 102L.
  • the optical pickup 102 receives a two-divided or four-divided guide light receiving element that receives the return light of the guide laser light LB1 from the guide layer 12, and a second light receiving the return light of the recording / reproducing laser light LB2 from the desired recording layer 13. And a divided or quadrant recording / reproducing light receiving element.
  • the optical pickup 102 emits a relatively high-intensity recording / reproducing laser beam LB2 when a recording operation on the optical disc 11 (particularly, a recording operation on a desired recording layer 13) is performed.
  • the optical pickup 102 emits a relatively low-intensity recording / reproducing laser beam LB2 when a reproducing operation on the optical disc 11 (particularly, a reproducing operation on a desired recording layer 13) is performed.
  • the guide light receiving element included in the optical pickup 102 receives the return light of the guide laser light LB1, thereby generating a push-pull signal resulting from the return light. Based on this push-pull signal, tracking control, discrimination of the center track CT corresponding to the discrimination mark group MG2, and reading of bit data corresponding to the information mark group MG1 are performed.
  • the recording / reproducing light receiving element included in the optical pickup 102 receives the return light of the recording / reproducing laser beam LB2 when a reproducing operation on the disk 11 (particularly, a reproducing operation on the desired recording layer 13) is performed. Thus, an RF signal resulting from the return light is generated. Based on this RF signal, the data recorded on the desired recording layer 13 is reproduced.
  • the recording / reproducing light receiving element included in the optical pickup 102 may generate a push-pull signal caused by the return light by receiving the return light of the recording / reproducing laser beam LB2. Tracking control may be performed based on this push-pull signal.
  • the memory 112 and the memory 212 are for controlling (i) each element such as the CPU 111 in the recording / reproducing apparatus 101 and each element such as the CPU 211 in the host computer 201 so that a recording operation and a reproducing operation described below are performed.
  • the computer program and (ii) various data necessary for the recording / reproducing operation are appropriately used to temporarily or permanently hold the data via the bus 106, the bus 206, and the like.
  • FIG. 30 is a block diagram showing a configuration of the signal recording / reproducing unit 103.
  • the signal recording / reproducing unit 103 includes a tracking control circuit 120 and a mark group detection circuit 130.
  • the tracking control circuit 120 performs tracking control based on a push-pull signal output from the guide light receiving element (that is, a push-pull signal generated from the return light of the guide laser beam LB1). For example, the tracking control circuit 120 generates a tracking control signal based on the push-pull signal and outputs the tracking control signal to the optical pickup 102 (more specifically, an actuator that drives the optical pickup 102 in the tracking direction). By doing so, tracking control is performed.
  • the tracking control itself may be performed in the same manner as the existing tracking control, and thus detailed description thereof is omitted.
  • the mark group detection circuit 130 is based on the push-pull signal output from the guide light receiving element (that is, the push-pull signal generated from the return light of the guide laser beam LB1), and the information mark group MG1 formed on the guide layer 12. Then, the discrimination mark group MG2 is detected. More specifically, the mark group detection circuit 130 detects the information mark group MG1 by monitoring fluctuations in the signal level of the push-pull signal output from the guide light receiving element, and the information mark group MG1 The synchronization data and bit data shown are detected.
  • the mark group detection circuit 130 detects the discrimination mark group MG2 by monitoring the fluctuation of the signal level of the push-pull signal output from the guide light receiving element, and Based on the determination mark group MG2, it is determined whether or not the guide track TR currently being traced is the center track CT.
  • the mark group detection circuit 130 includes an LPF (Low Path Filter) 1310, an LPF 1311, an S / H (Sample Hold) circuit 1312, S / H circuit 1313, differencer 1314, comparator 1315, synchronous data detector 1316, word marker detector 1318, nibble marker detector 1319, pre-data detector 1320, buffer memory 1321, and data
  • LPF Low Path Filter
  • S / H Sample Hold
  • comparator 1315 synchronous data detector 1316
  • word marker detector 1318 synchronous marker detector 1318
  • nibble marker detector 1319 pre-data detector 1320
  • buffer memory 1321 buffer memory 1321
  • An accumulation control unit 1322, an error correction unit 1323, a detection window generation unit 1324, and a reproduction timing generation unit 1325 are provided.
  • the push-pull signal output from the guide light receiving element is input to both LPFs 1310 and 1311.
  • the LPF 1310 is a filter for removing noise of the push-pull signal, and is a filter having a cutoff frequency through which the waveform of the frequency caused by the information mark group MG1 and the discrimination mark group MG2 is transmitted, for example.
  • the push-pull signal that has passed through the LPF 1310 is sampled and held by the S / H circuit 1312 at every predetermined timing.
  • the push-pull signal (that is, the signal level) sampled and held in the S / H circuit 1312 is input to the differentiator 1314. Note that the signal level of the push-pull signal sampled and held in the S / H circuit 1312 may vary depending on the patterns of the information mark group MG1 and the determination mark group MG2.
  • the LPF 1311 is a filter having a cutoff frequency through which a waveform caused by the eccentric component of the push-pull signal is transmitted including its phase.
  • the push-pull signal that has passed through the LPF 1311 is sampled and held at a predetermined timing in the S / H circuit 1313.
  • the push-pull signal (that is, the signal level) sampled and held in the S / H circuit 1313 is input to the differentiator 1314.
  • the signal level of the push-pull signal sampled and held in the S / H circuit 1313 corresponds to a reference value of the signal level of the push-pull signal (so-called zero level, substantially DC component).
  • the subtractor 1314 divides the signal level of the push-pull signal sampled and held in the S / H circuit 1313 from the signal level of the push-pull signal sampled and held in the S / H circuit 1312. As a result, the differentiator 1314 outputs the signal level of the push-pull signal from which the influence of the fluctuation of the reference value (so-called zero level) is eliminated.
  • the comparator 1315 compares the signal level of the push-pull signal (particularly, the push-pull signal corresponding to the information mark group MG1) output from the differentiator 1314 with a predetermined threshold value. As a result, the comparator 1315 determines whether the signal level of the push-pull signal is “0”, “+”, or “ ⁇ ”.
  • the comparator 1315 compares the signal level of the push-pull signal (particularly, the push-pull signal corresponding to the discrimination mark group MG2) output from the differentiator 1314 with a predetermined threshold value. And the above-described first threshold value a and second threshold value b are compared. As a result, the comparator 1315 determines whether the signal level of the push-pull signal is “0”, “+”, “ ⁇ ”, “+ indeterminate”, or “ ⁇ indeterminate”. Or “not adjacent”. In other words, the comparator 1315 determines whether the mark interval in which the push-pull signal is detected is “0 interval”, “+ interval”, “ ⁇ interval”, or “+ indefinite interval”. It is determined whether there is a “ ⁇ indefinite section” or a “non-adjacent section”.
  • the synchronization data detector 1316 detects synchronization data based on the comparison result in the comparator 1315. That is, the synchronization data detector 1316 detects the synchronization data by detecting a push-pull signal whose signal level varies in a manner corresponding to the synchronization data based on the comparison result in the comparator 1315.
  • the discrimination mark group detector 1317 detects the discrimination mark group MG2 based on the comparison result in the comparator 1315.
  • the detection of the discrimination mark group MG2 by the discrimination mark group detector 1317 is preferably performed immediately after the synchronization data is detected by the synchronization data detector 1316. This is because in the present embodiment, as described above, the discrimination mark group MG2 is formed immediately after the information mark group MG1 corresponding to the synchronization data (see FIG. 14).
  • the discrimination mark group detector 1317 determines whether or not the guide track TR traced by the guide laser beam LB1 is the center track CT based on the comparison result in the comparator 1315.
  • the word marker detector 1318 detects a word marker which is an example of bit data based on the comparison result in the comparator 1315. That is, the word marker detector 1318 detects a word marker by detecting a push-pull signal whose signal level varies in a manner corresponding to the word marker based on the comparison result in the comparator 1315. The word marker will be described later (see FIG. 32).
  • the detection of the word marker by the word marker detector 1318 is performed when the discrimination mark group detector 1317 determines that the guide track TR traced by the guide laser beam LB1 is the center track CT. That is, if the determination mark group detector 1317 determines that the guide track TR traced by the guide laser beam LB1 is not the center track CT, the word marker detector 1318 has been temporarily input with a push-pull signal. However, the word marker is not detected.
  • the nibble marker detector 1319 detects a nibble marker which is an example of bit data based on the comparison result in the comparator 1315. That is, the nibble marker detector 1319 detects the nibble marker by detecting a push-pull signal whose signal level varies in a manner corresponding to the nibble marker based on the comparison result in the comparator 1315. The nibble marker will be described later (see FIG. 32).
  • the detection of the nibble marker by the nibble marker detector 1319 is performed when the determination mark group detector 1317 determines that the guide track TR traced by the guide laser beam LB1 is the center track CT. That is, if the determination mark group detector 1317 determines that the guide track TR traced by the guide laser beam LB1 is not the center track CT, the nibble marker detector 1319 assumes that a push-pull signal has been input. Does not detect nibble markers.
  • the pre-data detector 1320 detects pre-data (that is, pre-format information itself) that is an example of bit data based on the comparison result in the comparator 1315. That is, the predata detector 1320 detects bit data other than the word marker and nibble marker as preformat information based on the comparison result in the comparator 1315.
  • the detection of the preformat information by the predata detector 1320 is performed when the discrimination mark group detector 1317 determines that the guide track TR traced by the guide laser beam LB1 is the center track CT. In other words, if the determination mark group detector 1317 determines that the guide track TR traced by the guide laser beam LB1 is not the center track CT, the pre-data detector 1320 has temporarily received a push-pull signal. However, preformat information is not detected.
  • the buffer memory 1321 temporarily stores the preformat information detected by the predata detector 1320 under the control of the data accumulation control unit 1323.
  • the data accumulation control unit 1322 controls the buffer memory 1321 so that the preformat information detected by the predata detector 1320 is stored in the buffer memory 1321 in order of ECC blocks described later. That is, the data accumulation control unit 1322 controls the buffer memory 1321 so that preformat information in units of ECC blocks (in other words, preformat information in units of words) is stored in order. Note that the preformat information stored in the buffer memory 1321 is preformat information detected by the predata detector 1320 when it is determined that the guide track TR traced by the guide laser beam LB1 is the center track CT. This is as described above.
  • the error correction unit 1323 performs error correction processing (ECC processing: Error Correction Code processing) on the preformat information stored in the buffer memory 1321.
  • ECC processing Error Correction Code processing
  • the preformat information that has been subjected to the ECC processing is transferred to the CPU 111 so as to be referred to during the recording operation and the reproducing operation.
  • the detection window generation unit 1324 generates a detection window that defines the timing when the comparator 1315 compares the signal level of the push-pull signal with the first threshold value a and the second threshold value b. As a result, the comparator 1315 compares the signal level of the push-pull signal with the first threshold value a and the second threshold value b in units of detection windows.
  • the detection of the synchronization data by the synchronization data detector 1317, the detection of the word marker by the word marker detector 1318, the detection of the nibble marker by the nibble marker detector 1319, and the detection of the preformat information by the predata detector 1320 are also performed. It may be performed in units of. Therefore, it is preferable that the detection window generation unit 1324 generates such a detection window.
  • the detection window is a window having a length corresponding to the above-described mark section (that is, a section in which an information recording mark or a discrimination recording mark is formed).
  • the timing generation unit 1325 appropriately generates 1 ECC block timing, 1 group timing, 1 slot timing, 1 wobble timing, and the like. By referring to these timings generated by the timing generation unit 1325, the data accumulation control unit 1322 and the error correction unit 1323 recognize the timing of the ECC block, group, slot, and wobble.
  • FIG. 31 is a flowchart showing an overall flow of the operation of the recording / reproducing apparatus 100 of the present embodiment.
  • the tracking control circuit 120 performs tracking control of the guide laser light LB1 based on the push-pull signal generated from the return light of the guide laser light LB1 (step S110).
  • a focus control circuit included in the recording / reproducing apparatus 100 performs focus control of the guide laser light LB1 based on a push-pull signal generated from the return light of the guide laser light LB1 (step S110).
  • the mark group detection circuit 130 may detect bit data based on a push-pull signal generated from the return light of the guide laser beam LB1.
  • the CPU 111 can acquire preformat information such as address information, clock information, and recording start timing information (step S120). The preformat information acquisition operation performed by the recording / reproducing apparatus 100 will be described in detail later with reference to FIGS.
  • the recording / reproducing laser beam LB2 is irradiated from the optical pickup 102 to a predetermined recording layer 13 of the plurality of recording layers 13.
  • the CPU 111 refers to the address information obtained by combining the bit data detected by the mark group detection circuit 130, and the recording / reproducing laser beam LB2 is applied to an appropriate region (more specifically, on the predetermined recording layer 13). Controls the optical pickup 102 and the signal recording / reproducing unit 103 so as to irradiate an area in which disc management information (to be described later) is recorded. As a result, the CPU 111 acquires disc management information (for example, media identification information, area management information, etc.) indicating the recording mode on the optical disc 11 (step S130).
  • disc management information for example, media identification information, area management information, etc.
  • the CPU 111 determines whether or not a recording operation is performed on a desired recording layer 13 among the plurality of recording layers 13 (step S140).
  • step S140 when it is determined that a recording operation on the desired recording layer 13 is performed (step S140: Yes), the recording / reproducing apparatus 100 performs a recording operation (step S150).
  • the recording operation performed by the recording / reproducing apparatus 100 will be described in detail later with reference to FIG.
  • step S140 when it is determined that the recording operation for the desired recording layer 13 is not performed (step S140: No), the CPU 111 determines the desired recording of the plurality of recording layers 13. It is determined whether or not the reproduction operation for the layer 13 is performed (step S160).
  • step S160 when it is determined that the reproduction operation for the desired recording layer 13 is performed (step S160: Yes), the recording / reproducing apparatus 100 performs the reproduction operation (step S170).
  • the reproduction operation performed by the recording / reproducing apparatus 100 will be described in detail later with reference to FIG.
  • step S160 when it is determined that the reproduction operation for the desired recording layer 13 is not performed (step S160: No), the recording / reproducing apparatus 100 may end the operation.
  • FIG. 32 is a data structure diagram showing a data structure of bit data in a slot included in the ECC block.
  • FIG. 33 is a data structure diagram showing a data structure of preformat information of each word included in the ECC block.
  • FIG. 13 shows an example in which three bit data exist in each slot. In this case, the structure of the three bit data included in one slot is classified into the three structures shown in FIG.
  • FIG. 32 shows an example in which a push-pull signal whose signal level changes to “0”, “+”, “0”, and “ ⁇ ” corresponds to a word marker.
  • the leading one bit data of the three bit data is followed by an array of 4-bit preformat information (such as this).
  • an array of 4-bit preformat information such as this
  • two bit data other than the head of the three bit data become the preformat information, while a nibble marker indicating that this is the head of “a nibble”.
  • FIG. 32 shows an example in which a push-pull signal whose signal level changes to “0”, “ ⁇ ”, “0”, and “+” corresponds to a nibble marker.
  • the preformat information corresponds to the bit data (bit 0) or bit data (bit 1) described above.
  • Bit data including the word marker shown at the top of FIG. 32 is assigned to all slots of the first group of each word.
  • all slots # 1 to # 8 included in group # 1 of word # 1 have the data structure shown at the top of FIG.
  • all of the slots # 1 to # 8 included in the group # 41 of the word # 2 have the data structure shown in the uppermost stage of FIG.
  • the slot # 1, slot # 3, slot # 5, and slot # 7 of the group # 2 to the group # 40 of the word # 1 have the data structure shown in the middle of FIG.
  • slot # 2, slot # 4, slot # 6 and slot # 8 of group # 2 to group # 40 of word # 1 have the data structure shown at the bottom of FIG. You may do it.
  • preformat information of one ECC block (for example, address information of the ECC block). Etc.) is obtained. That is, the preformat information of one ECC block shown in FIG. 33 is obtained by storing the preformat information detected by the predata detector 1320 in order from bit 1 with reference to the time point when the word marker is detected. At this time, as shown in FIG. 33, the preformat information indicates valid data from bit k (where k is an integer satisfying 1 ⁇ k ⁇ 8) to bit k + 3 and bit k + 5 to bit k + 8. Bit k + 4 and bit k + 9 indicate parity.
  • FIG. 34 is a flowchart showing the flow of the recording operation (step S120 in FIG. 31) of the recording / reproducing apparatus 100 of the present embodiment.
  • FIG. 35 is a plan view showing the information mark group MG1 that is read when it is determined that the groove track GT (k) with the track number k is the center track CT.
  • the synchronization data detector 1316 determines whether or not synchronization data has been detected based on the comparison result in the comparator 1315 (step S1211).
  • step S1211 determines again whether the synchronization data is detected.
  • step S1211 determines whether or not the guide track TR traced by the guide laser beam LB1 is the center track CT. Determination is made (step S1212). The operation for determining whether or not the guide track TR traced by the guide laser beam LB1 is the center track CT is as described above (see FIGS. 7 to 12).
  • step S1212 when it is determined that the guide track TR traced by the guide laser beam LB1 is not the center track CT (step S1212: No), the operations after step S1211 are repeated. That is, the synchronization data detector 1316 determines again whether synchronization data has been detected.
  • the word marker detector 1318 includes a comparator. Based on the comparison result in 1315, it is determined whether or not a word marker, which is an example of bit data, has been detected (step S1213). That is, the word marker detector 1318 determines whether or not a push-pull signal whose signal level fluctuates in a manner corresponding to the word marker is detected immediately after the push-pull signal corresponding to the discrimination mark group MG2 is detected. To do.
  • step S1213 determines again whether synchronization data has been detected.
  • step S1213 if it is determined that the word marker is detected as a result of the determination in step S1213 (step S1213: Yes), the preformat information is detected as bit data from now because the head of the word is detected. It is expected that. In other words, it is assumed that a slot having the middle data structure in FIG. 32 and a slot having the lowermost data structure in FIG. 32 are detected for one word.
  • step S1214 detection of the synchronization data by the synchronization data detector 1316 (step S1214) and determination of the center track CT by the discrimination mark group detector 1317 (step S1215) are performed again.
  • the synchronous data detection operation in step S1214 is the same as the synchronous data detection operation in step S1211.
  • step S1215 the operation for determining the center track CT in step S1212.
  • step S1214 when it is determined that the synchronization data is not detected or the guide track TR traced by the guide laser beam LB1 is not the center track CT (step S1214: No or step S1215). : No), the operation after step S1214 is repeated. That is, the synchronization data detector 1316 determines again whether synchronization data has been detected.
  • step S1214 when it is determined that the synchronization data is detected and the guide track TR traced by the guide laser beam LB1 is the center track CT (step S1214: Yes and In step S1215: Yes, the nibble marker detector 1319 determines whether a nibble marker, which is an example of bit data, is detected based on the comparison result in the comparator 1315 (step S1216). That is, the nibble marker detector 1319 determines whether or not a push-pull signal whose signal level varies in a manner corresponding to the nibble marker is detected immediately after the push-pull signal corresponding to the discrimination mark group MG2 is detected.
  • a nibble marker which is an example of bit data
  • step S1216 If it is determined that the nibble marker has been detected as a result of the determination in step S1216 (step S1216: Yes), it is estimated that a slot having the middle data structure in FIG. 32 has been detected. Accordingly, in this case, the pre-data detector 1320 detects 2-bit pre-format information that appears following the nibble marker based on the comparison result in the comparator 1315 (step S1217). The 2-bit preformat information is stored in the buffer memory 1321 (step S1217).
  • step S1216 determines whether the nibble marker has been detected as a result of the determination in step S1216 (step S1216: No).
  • the pre-data detector 1320 detects 3-bit pre-format information that appears following the discrimination mark group MG2 based on the comparison result in the comparator 1315 (step S1218).
  • the 3-bit preformat information is stored in the buffer memory 1321 (step S1218).
  • the data accumulation control unit 1322 determines whether 90-bit preformat information (that is, preformat information for one word) is stored in the buffer memory 1321 (step S1219).
  • step S1219: No If it is determined that the 90-bit preformat information is not stored as a result of the determination in step S1219 (step S1219: No), the operations after step S1214 are repeated. That is, the synchronization data detector 1316 determines again whether synchronization data has been detected.
  • step S1219 when it is determined that 90-bit preformat information is stored (step S1219: Yes), the error correction unit 1323 determines that the 90-bit preformat information (that is, one word) (In other words, preformat information of one ECC block) is subjected to error correction processing (step S1220). Thereafter, preformat information (for example, address information of the ECC block) of one ECC block on which error correction processing has been performed is transferred to the CPU 111 so that it can be referred to during recording and reproduction operations.
  • the 90-bit preformat information that is, one word
  • preformat information of one ECC block is subjected to error correction processing
  • the determination mark group detector 1317 determines that the guide track TR traced by the guide laser beam LB1 is the center track CT
  • the preformat information is detected and stored. Is called.
  • a case where a groove track GT (k) having a track number “k” is traced as shown in FIG. 35 will be described as an example.
  • the groove track GT (k) with the track number “k” is the center track CT, when tracing the slot # 1 of the group #j and when tracing the slot # 1 of the group # j + 1 If so, preformat information is detected and stored in accordance with the information mark group MG1 (black information mark group MG1 (k) in FIG. 35).
  • the push-pull signal acquired from the return light of the guide laser beam LB1 tracing the groove track GT (k) with the track number “k” is indicated by hatching in FIG.
  • the fluctuation of the signal level according to the information mark group MG1 (k + 1) formed in the slot # 2 of #j is included.
  • the discrimination mark group MG2 indicating that it is not the center track CT is detected although the synchronization data is detected.
  • the center track CT for the information mark group MG1 (k + 1) formed in the slot # 2 of the group #j is the guide laser beam LB1.
  • the land track LT (k + 1) with the track number “k + 1” is not the groove track GT (k) with the track number currently being traced “k”. For this reason, detection and storage of preformat information according to the information mark group MG1 (k + 1) formed in the slot # 2 of the group #j is not performed.
  • Stomach is the same.
  • FIG. 36 is a flowchart showing the flow of the recording operation (step S150 in FIG. 31) of the recording / reproducing apparatus 100 of the present embodiment.
  • the recording / reproducing apparatus 100 preferably refers to preformat information including address information, clock information, and recording start timing information when performing a recording operation. Therefore, the recording / reproducing apparatus 100 appropriately performs the preformat information acquisition operation (see step S120 in FIG. 31) when performing the recording operation shown in FIG.
  • the CPU 111 controls the optical pickup 102 and the signal recording / reproducing unit 103 so that the guide laser beam LB1 is irradiated onto the area on the guide layer 12 indicated by the desired address information (step). S151). At this time, the CPU 111 controls the optical pickup 102 and the signal recording / reproducing unit 103 while referring to address information obtained by combining the bit data detected by the mark group detection circuit 130.
  • the “desired address information” here is, for example, address information of an area where a recording operation is to be started.
  • the CPU 111 adjusts the focus of the recording / reproducing laser beam LB2 to the desired recording layer 13. Based on the push-pull signal generated from the return light of the recording / reproducing laser beam LB2, focus control of the recording / reproducing laser beam LB2 is performed (step S152).
  • the CPU 111 performs tracking control of the guide laser beam LB1 based on the push-pull signal generated from the return light of the guide laser beam LB1 (step S153).
  • the CPU 111 acquires address information, clock information, and recording start timing information obtained by combining the bit data detected by the mark group detection circuit 130 (step S154).
  • the CPU 111 determines whether or not the current timing matches the recording start timing information acquired in step S154 (step S155).
  • step S155 when it is determined that the current timing does not match the recording start timing information (step S155: No), the CPU 111 continues the determination in step S155.
  • step S155 if it is determined that the current timing coincides with the recording start timing information (step S155: Yes), the CPU 111 synchronizes with the clock information acquired in step S154, and selects the desired timing.
  • the optical pickup 102 and the signal recording / reproducing unit 103 are controlled so as to perform the recording operation on the recording layer 13 (step S156). As a result, the record information is recorded on the desired recording layer 13.
  • the CPU 111 determines whether or not to end the recording operation (step S157). For example, the CPU 111 may determine to end the recording operation when recording of recording information of a predetermined size or recording information to be recorded in the current recording operation is completed.
  • step S157 if it is determined not to end the recording operation (step S157: No), the CPU 111 continues the recording operation.
  • step S157 Yes
  • the CPU 111 updates the management information to reflect the current recording operation. Thereafter, the recording / reproducing apparatus 100 ends the recording operation.
  • FIG. 37 is a flowchart showing the flow of the reproducing operation (step S170 in FIG. 31) of the recording / reproducing apparatus 100 of the present embodiment.
  • the recording / reproducing apparatus 100 preferably refers to preformat information including address information, clock information, and recording start timing information when performing a reproducing operation. Therefore, the recording / reproducing apparatus 100 appropriately performs the preformat information acquisition operation (see step S120 in FIG. 31) even when performing the reproduction operation shown in FIG.
  • the CPU 111 controls the optical pickup 102 and the signal recording / reproducing unit 103 so that the guide laser beam LB1 is irradiated to the area on the guide layer 12 indicated by the desired address information (step). S171).
  • the CPU 111 controls the optical pickup 102 and the signal recording / reproducing unit 103 while referring to address information obtained by combining the bit data detected by the mark group detection circuit 130. Therefore, the recording / reproducing apparatus 100 appropriately performs the preformat information acquisition operation (see step S120 in FIG. 31) when performing the operation in step S171.
  • the “desired address information” here is, for example, address information of an area where a reproduction operation is to be started.
  • the CPU 111 adjusts the focus of the recording / reproducing laser beam LB2 to the desired recording layer 13. Based on the push-pull signal generated from the return light of the recording / reproducing laser beam LB2, focus control of the recording / reproducing laser beam LB2 is performed (step S172).
  • the CPU 111 is based on the push-pull signal generated from the return light of the recording / reproducing laser beam LB2 so that the recording mark indicating the recording information recorded on the desired recording layer 13 is irradiated with the recording / reproducing laser beam LB2. Then, tracking control of the recording / reproducing laser beam LB2 is performed (step S173).
  • the tracking control of the recording / reproducing laser beam LB2 is substantially performed by performing the tracking control of the guide laser beam LB1 based on the push-pull signal generated from the return light of the guide laser beam LB1. Also good.
  • the CPU 111 controls the optical pickup 102 and the signal recording / reproducing unit 103 so as to perform a reproducing operation on the desired recording layer 13 (step S176). As a result, the recorded information recorded on the desired recording layer 13 is reproduced.
  • the CPU 111 determines whether or not to end the recording operation (step S177). For example, the CPU 111 may determine to end the reproduction operation when the reproduction of the recording information of a predetermined size or the recording information to be reproduced in the current reproduction operation is completed.
  • step S177 when it is determined not to end the reproduction operation (step S177: No), the CPU 111 continues the reproduction operation.
  • step S177 when it is determined that the reproduction operation is to be ended (step S177: Yes), the recording / reproducing apparatus 100 ends the reproduction operation.
  • the recording / reproducing apparatus 100 can suitably perform the recording operation and the reproducing operation with respect to the optical disc 11 according to the above-described embodiment. For this reason, the recording / reproducing apparatus 100 of a present Example can perform suitably the recording operation and reproduction
  • the recording / reproducing apparatus 100 may perform only the recording operation (that is, the reproduction operation may not be performed) or may perform only the reproduction operation (that is, the recording operation may not be performed).
  • the present invention can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and a recording / reproducing apparatus and method involving such a change are also applicable to the technology of the present invention. Included in thought.

Abstract

An objective of the present invention is to carry out a record/play operation upon a recording medium with which a center track, among a plurality of guide tracks whereupon an information mark group is formed and which is located near the center, is suitably assessed. A record/play device (100) carries out a record/play operation upon a recording medium (11) which comprises: a guide layer (12) whereupon is formed an information mark group (MG1), and an assessment mark group (MG2) which includes a pair of assessment recording marks (ML2, MR2) which are shifted laterally by a prescribed distance with the track center of a center track being a reference and the respective widths thereof being twice or more the width of a guide track; and a recording layer (13). The record/play device (100) further comprises: a detection means (103) for detecting a first push-pull signal from a returning light of a guide laser beam which is projected upon the assessment mark group; and an assessment means (111) for assessing, on the basis of the first push-pull signal which the detection means has detected, whether the guide track which the guide laser beam traces is the center track.

Description

記録再生装置及び方法Recording / reproducing apparatus and method
　本発明は、例えば多数の記録層を備える光ディスク等の記録媒体に対する記録動作及び再生動作の少なくとも一方を行う記録再生装置及び方法の技術分野に関する。 The present invention relates to a technical field of a recording / reproducing apparatus and method for performing at least one of a recording operation and a reproducing operation with respect to a recording medium such as an optical disc having a large number of recording layers.
　多数の記録層を備える記録媒体として、例えば記録動作及び再生動作の少なくとも一方の実際の対象となる複数の記録層と、トラッキング用のガイドトラックが形成されたガイド層とを有する記録媒体（例えば、いわゆるガイド層分離型光ディスク）が知られている（特許文献１等参照）。このような記録媒体に対する記録動作及び再生動作の少なくとも一方を行う記録再生装置は、ガイド層のガイドトラックを読み取るためのガイドレーザ光と、記録層に対する記録動作及び再生動作の少なくとも一方を行うための記録再生レーザ光とを照射する。記録再生装置は、ガイドレーザ光の戻り光から得られるプッシュプル信号に基づいてトラッキング制御を行いながら、記録再生用レーザ光を記録層に照射することで記録動作及び再生動作の少なくとも一方を行う。 As a recording medium including a large number of recording layers, for example, a recording medium having a plurality of recording layers that are actually targets of at least one of a recording operation and a reproducing operation, and a guide layer on which a tracking guide track is formed (for example, A so-called guide layer separation type optical disc) is known (see Patent Document 1). A recording / reproducing apparatus that performs at least one of a recording operation and a reproducing operation with respect to such a recording medium has a guide laser beam for reading the guide track of the guide layer, and at least one of the recording operation and the reproducing operation with respect to the recording layer. The recording / reproducing laser beam is irradiated. The recording / reproducing apparatus performs at least one of the recording operation and the reproducing operation by irradiating the recording layer with the recording / reproducing laser beam while performing tracking control based on the push-pull signal obtained from the return light of the guide laser beam.
　尚、ガイド層分離型光ディスクを開示する先行技術文献ではないものの、後述する本発明に関連する先行技術文献として、特許文献２から特許文献１１があげられる。 In addition, although it is not a prior art document disclosing the guide layer separation type optical disc, Patent Documents 2 to 11 are cited as prior art documents related to the present invention described later.
特許第４０３７０３４公報Japanese Patent No. 4037034 特開平１０－３０８０３７号公報Japanese Patent Laid-Open No. 10-308037 特許第３７２９４６７公報Japanese Patent No. 3729467 特許第３６６５５８８公報Japanese Patent No. 3665588 特許第３７４９４４号公報Japanese Patent No. 374944 特開２００３－３２３７２５号公報JP 2003-323725 A 特開２００４－１７８７８１号公報JP 2004-177871 A 特開平８－２７９１６０号公報JP-A-8-279160 特開平８－４５０８０号公報Japanese Patent Laid-Open No. 8-45080 特許第３２０５１５４号公報Japanese Patent No. 3205154 特許第３６９３８１３号公報Japanese Patent No. 3693913
　ところで、このような記録媒体では、何らかのデータ（例えば、アドレス情報やクロック情報や記録開始タイミング情報等の制御情報を示すデータ）をガイド層に予め記録しておきたいという要請がある。この場合、記録層に形成される記録マーク及び記録スペースの組み合わせと同様に、記録マーク及び記録スペースの組み合わせをガイド層にも形成することで、データをガイド層に記録する方法が一例として想定される。 By the way, in such a recording medium, there is a request to record in advance some data (for example, data indicating control information such as address information, clock information, and recording start timing information) in the guide layer. In this case, a method of recording data on the guide layer by forming the combination of the recording mark and recording space on the guide layer as well as the combination of the recording mark and recording space formed on the recording layer is assumed as an example. The
　しかしながら、当該記録マーク及び記録スペースの組み合わせをガイド層に形成することでデータがガイド層に記録される場合には、記録再生装置は、ガイドレーザ光の戻り光から、トラッキング用のプッシュプル信号のみならず、制御情報を読み取るためのＲＦ信号（いわゆる、総和信号）を取得する必要がある。しかしながら、プッシュプル信号の特性とＲＦ信号の特性とが異なることに起因して、プッシュプル信号及びＲＦ信号の双方を同時に取得することは、プッシュプル信号の取得の精度に何らかの影響を与えかねないという技術的な問題点が生ずる。つまり、プッシュプル信号及びＲＦ信号の双方を同時に取得することは、ガイド層の本来の目的であるトラッキング制御に何らかの影響を与えかねないという技術的な問題点が生ずる。 However, when data is recorded on the guide layer by forming the combination of the recording mark and the recording space in the guide layer, the recording / reproducing apparatus only detects the push-pull signal for tracking from the return light of the guide laser beam. Instead, it is necessary to acquire an RF signal (so-called sum signal) for reading the control information. However, due to the difference between the characteristics of the push-pull signal and the RF signal, acquiring both the push-pull signal and the RF signal at the same time may have some influence on the accuracy of acquiring the push-pull signal. This causes a technical problem. In other words, obtaining both the push-pull signal and the RF signal at the same time causes a technical problem that the tracking control, which is the original purpose of the guide layer, may have some influence.
　そこで、本願出願時点では未だ公知ではないものの、本願発明者等によって、ガイド層上の複数のガイドトラックの夫々に、夫々のガイドトラックのトラック中心から左右に等距離シフトしている一対の記録マークが組み合わせられた同一の情報用マーク群を形成する技術の開発が進められている（例えば、特願２０１２－０１００８５号）。しかしながら、この技術では、複数のガイドトラックの夫々に同一の情報用マーク群が形成されるがゆえに、一のガイドトラックをセンタートラックとする複数のガイドトラックの夫々に形成される一の情報用マーク群は、一のガイドトラックに隣接する他のガイドトラックにも形成される。従って、本来は一のガイドトラックにスポット中心を一致させたガイドレーザ光を用いて一の情報用マーク群が読み取られるべきところ、他のガイドトラックにスポット中心を一致させたガイドレーザ光を用いて一の情報用マーク群が読み取られてしまうおそれがある。このとき、例えば情報用マーク群がアドレス情報を示している場合には、アドレス情報の誤検出が発生してしまうおそれがある。つまり、他のガイドトラックにスポット中心を一致させたガイドレーザ光を用いて一の情報用マーク群を読み取った記録再生装置は、他のガイドトラックが一のガイドトラックであると誤って認識してしまうおそれがある。このような状況を考慮すれば、ガイド層上に形成された情報用マーク群が好適に読み取られるためには、複数のガイドトラックのうち中心付近に位置するセンタートラックが好適に判別されることが好ましい。つまり、センタートラックが好適に判別されれば、一のガイドトラックにスポット中心を一致させたガイドレーザ光を用いて、一のガイドトラックをセンタートラックとする複数のガイドトラックの夫々に形成される一の情報用マーク群が好適に読み取られることになる。言い換えれば、センタートラックが好適に判別されれば、一のガイドトラックとは異なる他のガイドトラックにスポット中心を一致させたガイドレーザ光を用いて一のガイドトラックをセンタートラックとする複数のガイドトラックの夫々に形成される一の情報用マーク群が読み取られることに起因した技術的不都合（例えば、上述したアドレス情報の誤検出等）が発生しなくなる。 Therefore, although not yet known at the time of filing of the present application, the inventors of the present application each of a plurality of guide tracks on the guide layer shifts a pair of recording marks that are shifted equidistant from the center of each guide track to the left and right. Development of a technique for forming the same information mark group in which the two are combined is underway (for example, Japanese Patent Application No. 2012-010085). However, in this technique, since the same information mark group is formed on each of the plurality of guide tracks, one information mark formed on each of the plurality of guide tracks having one guide track as a center track. Groups are also formed on other guide tracks adjacent to one guide track. Therefore, one information mark group should be read by using a guide laser beam whose spot center coincides with one guide track, but a guide laser beam whose spot center coincides with another guide track. One information mark group may be read. At this time, for example, when the information mark group indicates the address information, there is a risk of erroneous detection of the address information. In other words, a recording / reproducing apparatus that has read one information mark group using a guide laser beam whose spot center coincides with another guide track erroneously recognizes that the other guide track is one guide track. There is a risk that. In consideration of such a situation, in order for the information mark group formed on the guide layer to be read appropriately, a center track located near the center among the plurality of guide tracks can be preferably determined. preferable. In other words, if the center track is suitably determined, a guide laser beam having a spot center aligned with one guide track is used to form each of the plurality of guide tracks having the one guide track as the center track. This information mark group is preferably read. In other words, if the center track is suitably determined, a plurality of guide tracks having the one guide track as the center track using the guide laser beam having the spot center matched to another guide track different from the one guide track. Therefore, the technical inconvenience (for example, erroneous detection of the address information described above) due to the reading of one information mark group formed on each of the information mark is not generated.
　本発明は、上述した多数の記録層を備える光ディスクにおいて、ガイド層上の複数のガイドトラックの夫々に記録された情報用マーク群を好適に読み取るために、情報用マーク群が形成された複数のガイドトラックのうちの中心付近に位置するセンタートラックを好適に判別することが可能な記録媒体に対する記録動作及び再生動作の少なくとも一方を行う記録再生装置及び方法を提供することを課題とする。 The present invention provides a plurality of information mark groups formed on an optical disc having a large number of recording layers as described above in order to suitably read information mark groups recorded on a plurality of guide tracks on the guide layer. It is an object of the present invention to provide a recording / reproducing apparatus and method for performing at least one of a recording operation and a reproducing operation with respect to a recording medium capable of suitably discriminating a center track located near the center of guide tracks.
　上記課題を解決するために、記録再生装置は、(i-1)トラッキング用のガイドトラックが形成されているガイド層と、(i-2)前記ガイド層上に積層されている複数の記録層とを備える記録媒体であって、(ii)前記ガイド層には、(ii-1)互いに隣接する複数のガイドトラックの夫々に形成される情報用マーク群と、(ii-2)前記情報用マーク群が形成されている前記複数のガイドトラックのうち中心付近に位置するガイドトラックであるセンタートラックを判別するための判別用マーク群とが形成されており、(iii)前記判別用マーク群は、(iii-1)前記センタートラックのトラック中心を基準として左右に所定距離シフトしている一対の判別用記録マークであって、且つ(iii-2)夫々の判別用記録マークの幅が前記ガイドトラックの幅の２倍以上となる一対の判別用記録マークを含んでいる記録媒体に対して記録動作及び再生動作の少なくとも一方を行う記録再生装置であって、前記判別用マーク群に照射された前記ガイドレーザ光の戻り光から第１プッシュプル信号を検出する検出手段と、前記検出手段が検出した前記第１プッシュプル信号に基づいて、前記ガイドレーザ光がトレースしている前記ガイドトラックが前記センタートラックであるか否かを判別する判別手段とを備える。 In order to solve the above problems, a recording / reproducing apparatus includes: (i-1) a guide layer in which a guide track for tracking is formed; and (i-2) a plurality of recording layers stacked on the guide layer. (Ii) the guide layer includes (ii-1) an information mark group formed on each of a plurality of adjacent guide tracks, and (ii-2) the information layer. A determination mark group for determining a center track which is a guide track located near the center among the plurality of guide tracks in which the mark group is formed, and (iii) the determination mark group (Iii-1) a pair of discriminating recording marks shifted by a predetermined distance left and right with respect to the track center of the center track, and (iii-2) the width of each discriminating recording mark is the guide A pair of discriminators that are more than twice the width of the track A recording / reproducing apparatus that performs at least one of a recording operation and a reproducing operation with respect to a recording medium including a recording mark, wherein a first push-pull signal is generated from a return light of the guide laser light irradiated to the discrimination mark group. And detecting means for detecting whether or not the guide track traced by the guide laser beam is the center track based on the first push-pull signal detected by the detecting means. Is provided.
　上記課題を解決するために、記録再生方法は、(i-1)トラッキング用のガイドトラックが形成されているガイド層と、(i-2)前記ガイド層上に積層されている複数の記録層とを備える記録媒体であって、(ii)前記ガイド層には、(ii-1)互いに隣接する複数のガイドトラックの夫々に形成される情報用マーク群と、(ii-2)前記情報用マーク群が形成されている前記複数のガイドトラックのうち中心付近に位置するガイドトラックであるセンタートラックを判別するための判別用マーク群とが形成されており、(iii)前記判別用マーク群は、(iii-1)前記センタートラックのトラック中心を基準として左右に所定距離シフトしている一対の判別用記録マークであって、且つ(iii-2)夫々の判別用記録マークの幅が前記ガイドトラックの幅の２倍以上となる一対の判別用記録マークを含んでいる記録媒体に対して記録動作及び再生動作の少なくとも一方を行う記録再生方法であって、前記判別用マーク群に照射された前記ガイドレーザ光の戻り光から第１プッシュプル信号を検出する検出工程と、前記検出工程が検出した前記第１プッシュプル信号に基づいて、前記ガイドレーザ光がトレースしている前記ガイドトラックが前記センタートラックであるか否かを判別する判別工程とを備える。 In order to solve the above problems, a recording / reproducing method includes (i-1) a guide layer in which a guide track for tracking is formed, and (i-2) a plurality of recording layers stacked on the guide layer. (Ii) the guide layer includes (ii-1) an information mark group formed on each of a plurality of adjacent guide tracks, and (ii-2) the information layer. A determination mark group for determining a center track which is a guide track located near the center among the plurality of guide tracks in which the mark group is formed, and (iii) the determination mark group (Iii-1) a pair of discriminating recording marks shifted by a predetermined distance left and right with respect to the track center of the center track, and (iii-2) the width of each discriminating recording mark is the guide A pair of discriminators that are more than twice the width of the track A recording / reproducing method for performing at least one of a recording operation and a reproducing operation on a recording medium including a recording mark, wherein a first push-pull signal is obtained from a return light of the guide laser light irradiated to the discrimination mark group. And a determination step of determining whether or not the guide track traced by the guide laser beam is the center track based on the first push-pull signal detected by the detection step. Is provided.
一枚の光ディスクを構成する複数の層を、その積層方向（図１中、上下方向）について相互に間隔をあけて分解することで、各層を見易くしてなる模式的な斜視図である。It is a typical perspective view which makes each layer easy to see by disassembling a plurality of layers constituting one optical disk at intervals in the stacking direction (vertical direction in FIG. 1). 光ディスクの断面を、ガイドレーザ光及び記録再生レーザ光の照射態様と共に示す断面図である。It is sectional drawing which shows the cross section of an optical disk with the irradiation aspect of a guide laser beam and a recording / reproducing laser beam. グルーブトラックに形成される情報用マーク群を構成する一対の情報用記録マークの構成を示す平面図である。It is a top view which shows the structure of a pair of information recording mark which comprises the information mark group formed in a groove track. グルーブトラックに形成される情報用マーク群によって多種類のデータ（具体的には、ビットデータ及び同期データ）が記録される態様を示す平面図である。It is a top view which shows the aspect in which many types of data (specifically bit data and synchronous data) are recorded by the information mark group formed in a groove track. ランドトラックに形成される情報用マーク群を構成する一対の情報用記録マークの構成を示す平面図である。It is a top view which shows the structure of a pair of information recording mark which comprises the information mark group formed in a land track. ランドトラックに形成される情報用マーク群によって多種類のデータ（具体的には、ビットデータ及び同期データ）が記録される態様を示す平面図である。It is a top view which shows the aspect in which many types of data (specifically bit data and synchronous data) are recorded by the mark group for information formed in a land track. グルーブトラックに形成される情報用マーク群のための判別用マーク群の構成を示す平面図である。It is a top view which shows the structure of the discrimination mark group for the information mark group formed in a groove track. 判別用マーク群が形成されたグルーブトラック上をトレースするガイドレーザ光の戻り光から得られるプッシュプル信号の信号レベルを示すグラフである。It is a graph which shows the signal level of the push pull signal obtained from the return light of the guide laser beam which traces on the groove track in which the mark group for discrimination was formed. 図７に示す判別用マーク群を用いてセンタートラックを判別する動作を示すフローチャートである。It is a flowchart which shows the operation | movement which discriminate | determines a center track | truck using the discrimination | determination mark group shown in FIG. ランドトラックに形成される情報用マーク群１のための判別用マーク群の構成を示す平面図である。It is a top view which shows the structure of the discrimination mark group for the information mark group 1 formed in a land track. 判別用マーク群が形成されたランドトラック上をトレースするガイドレーザ光の戻り光から得られるプッシュプル信号の信号レベルを示すグラフである。It is a graph which shows the signal level of the push pull signal obtained from the return light of the guide laser beam which traces on the land track in which the mark group for discrimination was formed. 図１０に示す判別用マーク群を用いてセンタートラックを判別する動作を示すフローチャートである。11 is a flowchart showing an operation of discriminating a center track using the discrimination mark group shown in FIG. ガイド層（更には、記録層）のデータ構造を示すデータ構造図である。It is a data structure figure which shows the data structure of a guide layer (further, a recording layer). 特定のスロットに形成される情報用マーク群及び判別用マーク群の一例を示す平面図である。It is a top view which shows an example of the information mark group and discrimination mark group which are formed in a specific slot. 複数の情報用マーク群及び判別用マーク群が複数のスロットに分散して記録される態様を示す平面図である。It is a top view which shows the aspect by which a some information mark group and a discrimination mark group are disperse | distributed and recorded on a some slot. グルーブトラックの凹部の深さ（つまり、ランドトラックに対するグルーブトラックの相対的な深さ）とプッシュプル信号及びＲＦ信号の信号レベルとの関係を示すグラフである。It is a graph which shows the relationship between the depth of the recessed part of a groove track (namely, the relative depth of a groove track with respect to a land track), and the signal level of a push pull signal and RF signal. 単一のグルーブトラックに情報用マーク群が形成される比較例を示す平面図である。It is a top view which shows the comparative example by which the information mark group is formed in a single groove track. フォーカス偏差とプッシュプル信号の振幅との間の関係を示すグラフである。It is a graph which shows the relationship between a focus deviation and the amplitude of a push pull signal. ガイド層でのガイドレーザ光のビームスポットとグルーブトラック並びに一対の情報用記録マークとの位置関係を示す平面図である。It is a top view which shows the positional relationship of the beam spot of a guide laser beam in a guide layer, a groove track | truck, and a pair of information recording mark. 一対の情報用記録マーク並びにトラック中心上に位置する情報用記録マークが含まれる同期データを構成する情報用マーク群から得られるプッシュプル信号を示すグラフである。It is a graph which shows the push pull signal obtained from the information mark group which comprises the synchronous data containing a pair of information recording mark and the information recording mark located on the track center. 第１変形例の判別用マーク群が形成されたグルーブトラック上をトレースするガイドレーザ光の戻り光から得られるプッシュプル信号の信号レベルを、グルーブトラックに形成される第１変形例の判別用マーク群の構成と対応付けて示すグラフである。The signal level of the push-pull signal obtained from the return light of the guide laser beam that traces on the groove track on which the discrimination mark group of the first modification is formed is determined as the discrimination mark of the first modification formed on the groove track. It is a graph shown in association with a group configuration. 図２１に示す第１変形例の判別用マーク群を用いてセンタートラックを判別する動作を示すフローチャートである。It is a flowchart which shows the operation | movement which discriminate | determines a center track | truck using the discrimination | determination mark group of the 1st modification shown in FIG. 第２変形例の判別用マーク群が形成されたランドトラック上をトレースするガイドレーザ光の戻り光から得られるプッシュプル信号の信号レベルを、ランドトラックに形成される第２変形例の判別用マーク群の構成と対応付けて示すグラフである。The signal level of the push-pull signal obtained from the return light of the guide laser beam that traces on the land track on which the discrimination mark group of the second modification is formed is used as the discrimination mark of the second modification formed on the land track. It is a graph shown in association with a group configuration. 図２３に示す第２変形例の判別用マーク群を用いてセンタートラックを判別する動作を示すフローチャートである。FIG. 24 is a flowchart showing an operation of discriminating the center track using the discrimination mark group of the second modification shown in FIG. 23. FIG. 第３変形例の判別用マーク群が形成されたランドトラック上をトレースするガイドレーザ光の戻り光から得られるプッシュプル信号の信号レベルを、ランドトラックに形成される第３変形例の判別用マーク群の構成と対応付けて示すグラフである。The signal level of the push-pull signal obtained from the return light of the guide laser beam that traces on the land track on which the discrimination mark group of the third modification is formed is used as the discrimination mark of the third modification formed on the land track. It is a graph shown in association with a group configuration. 図２５に示す第３変形例の判別用マーク群を用いてセンタートラックを判別する動作を示すフローチャートである。FIG. 26 is a flowchart showing an operation of discriminating a center track using the discrimination mark group of the third modification shown in FIG. 25. FIG. ランドトラックに形成される第４変形例の判別用マーク群の構成を示す平面図である。It is a top view which shows the structure of the discrimination mark group of the 4th modification formed in a land track. 図２７に示す第４変形例の判別用マーク群を用いてセンタートラックを判別する動作を示すフローチャートである。It is a flowchart which shows the operation | movement which discriminate | determines a center track | truck using the discrimination | determination mark group of the 4th modification shown in FIG. 本実施例の記録再生装置の構成を示すブロック図である。It is a block diagram which shows the structure of the recording / reproducing apparatus of a present Example. 信号記録再生部の構成を示すブロック図である。It is a block diagram which shows the structure of a signal recording / reproducing part. 本実施例の記録再生装置の動作の全体の流れを示すフローチャートである。It is a flowchart which shows the flow of the whole operation | movement of the recording / reproducing apparatus of a present Example. ＥＣＣブロックに含まれるスロット内でのビットデータのデータ構造を示すデータ構造図である。It is a data structure figure which shows the data structure of the bit data in the slot contained in an ECC block. ＥＣＣブロックに含まれる各ワードのプリフォーマット情報のデータ構造を示すデータ構造図である。It is a data structure figure which shows the data structure of the preformat information of each word contained in an ECC block. 本実施例の記録再生装置の記録動作（図３１のステップＳ１２０）の流れを示すフローチャートである。It is a flowchart which shows the flow of recording operation | movement (step S120 of FIG. 31) of the recording / reproducing apparatus of a present Example. トラック番号がｋとなるグルーブトラックがセンタートラックであると判定される場合に読み取られる情報用マーク群を示す平面図である。It is a top view which shows the information mark group read when it determines with the groove track whose track number is k being a center track. 本実施例の記録再生装置の記録動作（図３１のステップＳ１５０）の流れを示すフローチャートである。It is a flowchart which shows the flow of recording operation | movement (step S150 of FIG. 31) of the recording / reproducing apparatus of a present Example. 本実施例の記録再生装置の再生動作（図３１のステップＳ１７０）の流れを示すフローチャートである。It is a flowchart which shows the flow of the reproducing operation (step S170 of FIG. 31) of the recording / reproducing apparatus of a present Example.
　以下、記録再生装置及び方法の実施形態について順に説明する。 Hereinafter, embodiments of the recording / reproducing apparatus and method will be described in order.
　（記録再生装置の実施形態）
　＜１＞
　本実施形態の記録再生装置は、(i-1)トラッキング用のガイドトラックが形成されているガイド層と、(i-2)前記ガイド層上に積層されている複数の記録層とを備える記録媒体であって、(ii)前記ガイド層には、(ii-1)互いに隣接する複数のガイドトラックの夫々に形成される情報用マーク群と、(ii-2)前記情報用マーク群が形成されている前記複数のガイドトラックのうち中心付近に位置するガイドトラックであるセンタートラックを判別するための判別用マーク群とが形成されており、(iii)前記判別用マーク群は、(iii-1)前記センタートラックのトラック中心を基準として左右に所定距離シフトしている一対の判別用記録マークであって、且つ(iii-2)夫々の判別用記録マークの幅が前記ガイドトラックの幅の２倍以上となる一対の判別用記録マークを含んでいる記録媒体に対して記録動作及び再生動作の少なくとも一方を行う記録再生装置であって、前記判別用マーク群に照射された前記ガイドレーザ光の戻り光から第１プッシュプル信号を検出する検出手段と、前記検出手段が検出した前記第１プッシュプル信号に基づいて、前記ガイドレーザ光がトレースしている前記ガイドトラックが前記センタートラックであるか否かを判別する判別手段とを備える。 (Embodiment of recording / reproducing apparatus)
<1>
The recording / reproducing apparatus of the present embodiment includes (i-1) a guide layer in which a guide track for tracking is formed, and (i-2) a recording layer including a plurality of recording layers stacked on the guide layer. (Ii) the guide layer is formed with (ii-1) an information mark group formed on each of a plurality of guide tracks adjacent to each other; and (ii-2) the information mark group is formed. A discriminating mark group for discriminating a center track that is a guide track located near the center of the plurality of guide tracks, and (iii) the discriminating mark group is (iii- 1) a pair of discriminating recording marks shifted by a predetermined distance from side to side with respect to the track center of the center track, and (iii-2) the width of each discriminating recording mark is equal to the width of the guide track Includes a pair of discriminating recording marks that are more than doubled A recording / reproducing apparatus that performs at least one of a recording operation and a reproducing operation with respect to a recording medium, and that detects a first push-pull signal from a return light of the guide laser light irradiated to the discrimination mark group And a determining means for determining whether or not the guide track traced by the guide laser beam is the center track based on the first push-pull signal detected by the detecting means.
　本実施形態の記録再生装置による記録動作及び再生動作の少なくとも一方の対象となる記録媒体によれば、ガイド層と複数の記録層とを備えている。ガイド層には、トラッキング用のガイドトラックが形成されている。このため、当該記録媒体に対して（より具体的には、当該記録媒体が備える複数の記録層に対して）記録動作及び再生動作の少なくとも一方を行う記録再生装置は、ガイド層に照射されるガイドレーザ光の戻り光（つまり、ガイド層によって反射されたガイドレーザ光）に基づいて、ガイドトラックとガイドレーザ光のビームスポットとの位置関係に応じたプッシュプル信号を取得することができる。その結果、記録再生装置は、当該プッシュプル信号に基づいて、トラッキング制御を行うことができる。 The recording medium that is the target of at least one of the recording operation and the reproducing operation by the recording / reproducing apparatus of the present embodiment includes a guide layer and a plurality of recording layers. A tracking track for tracking is formed on the guide layer. Therefore, a recording / reproducing apparatus that performs at least one of a recording operation and a reproducing operation on the recording medium (more specifically, on a plurality of recording layers included in the recording medium) irradiates the guide layer. Based on the return light of the guide laser light (that is, the guide laser light reflected by the guide layer), a push-pull signal corresponding to the positional relationship between the guide track and the beam spot of the guide laser light can be acquired. As a result, the recording / reproducing apparatus can perform tracking control based on the push-pull signal.
　本実施形態では、ガイド層には、情報用マーク群と判別用マーク群とが形成されている。 In this embodiment, an information mark group and a discrimination mark group are formed on the guide layer.
　情報用マーク群は、ガイド層上に所望のビットデータ（例えば、アドレス情報やクロック情報や記録開始タイミング情報等の制御情報を示すビットデータ）を記録するために、ガイド層上に形成されるマーク群である。情報用マーク群は、互いに隣接する複数のガイドトラックの夫々に形成される。つまり、本実施形態では、互いに隣接する複数のガイドトラックの夫々には、同一の情報用マーク群が形成されている。より具体的には、例えば、一のガイドトラックが中心付近に位置する（つまり、一のガイドトラックがセンタートラックとなる）複数のガイドトラックの夫々には、一の情報用マーク群が形成される。一方で、一のガイドトラックとは異なる他のガイドトラックが中心付近に位置する（つまり、他のガイドトラックがセンタートラックとなる）複数のガイドトラックの夫々には、一の情報用マーク群とは異なる他の情報用マーク群が形成される。その結果、異なる情報用マーク群に対して異なるビットデータを割り当てることで、当該情報用マーク群を用いてビットデータをガイド層に記録することができる。 The information mark group is a mark formed on the guide layer in order to record desired bit data (for example, bit data indicating control information such as address information, clock information, and recording start timing information) on the guide layer. Is a group. The information mark group is formed on each of a plurality of guide tracks adjacent to each other. That is, in the present embodiment, the same information mark group is formed in each of a plurality of guide tracks adjacent to each other. More specifically, for example, one information mark group is formed in each of a plurality of guide tracks in which one guide track is located near the center (that is, one guide track serves as a center track). . On the other hand, for each of a plurality of guide tracks in which another guide track different from the one guide track is located near the center (that is, the other guide track is the center track), one information mark group is Different other information mark groups are formed. As a result, by assigning different bit data to different information mark groups, the bit data can be recorded on the guide layer using the information mark groups.
　判別用マーク群は、同一の情報用マーク群が形成されている複数のガイドトラックのうちの中心付近に位置する（言い換えれば、最も中心に近い）ガイドトラックであるセンタートラックを判別するためのマーク群である。判別用マーク群は、一対の判別用記録マークを含んでいる。判別用マーク群は、一対の判別用記録マークを一つだけ含んでいてもよいし、一対の判別用記録マークを複数含んでいてもよい。一対の判別用記録マークは、センタートラックのトラック中心を基準として左右に所定距離シフトしている一対の記録マークである。つまり、一対の判別用記録マークは、センタートラックのトラック中心を基準として左側に所定距離シフトしている記録マークとセンタートラックのトラック中心を基準として右側に所定距離シフトしている記録マークとを含む一対の記録マークである。加えて、一対の判別用記録マークの夫々の幅（つまり、ガイドトラックの進行方向に対して直交する方向であって、記録媒体の半径方向に沿った方向の長さ）は、ガイドトラックの幅の２倍以上となる。つまり、一対の判別用記録マークの夫々は、２つ以上のガイドトラックに跨って分布するように形成される。 The discrimination mark group is a mark for discriminating a center track which is a guide track located near the center (in other words, closest to the center) among a plurality of guide tracks on which the same information mark group is formed. Is a group. The discrimination mark group includes a pair of discrimination recording marks. The discrimination mark group may include only one pair of discrimination recording marks, or may include a plurality of pairs of discrimination recording marks. The pair of discriminating recording marks is a pair of recording marks shifted by a predetermined distance from side to side with respect to the track center of the center track. That is, the pair of determination recording marks includes a recording mark shifted to the left by a predetermined distance with respect to the track center of the center track and a recording mark shifted to the right by a predetermined distance with respect to the track center of the center track. A pair of recording marks. In addition, the width of each of the pair of discrimination recording marks (that is, the length in the direction perpendicular to the traveling direction of the guide track and along the radial direction of the recording medium) is the width of the guide track. More than twice. That is, each of the pair of determination recording marks is formed so as to be distributed over two or more guide tracks.
　尚、判別用マーク群が含んでいる一対の判別用記録マークの全てが、センタートラックのトラック中心から同一距離シフトしていなくともよい。例えば、判別用マーク群は、センタートラックのトラック中心から左右に第１距離シフトしている一対の第１判別用記録マークと、センタートラックのトラック中心から左右に第２距離（但し、第２距離は第１距離とは異なる）シフトしている一対の第２判別用記録マークとを含んでいてもよい。もちろん、判別用マーク群は、センタートラックのトラック中心から左右に第１距離シフトしている一対の第１判別用記録マークと、センタートラックのトラック中心から左右に第１距離シフトしている一対の第２判別用記録マークとを含んでいてもよい。 Note that all of the pair of discrimination recording marks included in the discrimination mark group need not be shifted from the center of the center track by the same distance. For example, the discrimination mark group includes a pair of first discrimination recording marks shifted by a first distance from the center of the center track to the left and right and a second distance from the center of the center track to the left and right (however, the second distance). May be different from the first distance) and may include a pair of shifted second discrimination recording marks. Of course, the discrimination mark group includes a pair of first discrimination recording marks shifted by a first distance to the left and right from the track center of the center track, and a pair of shifts shifted by a first distance to the left and right from the track center of the center track. It may include a second discrimination recording mark.
　また、判別用マーク群は、同一の情報用マーク群と組になるように形成されていることが好ましい。この場合、例えば、あるガイドトラックがセンタートラックとなる複数のガイドトラックの夫々に複数の異なる情報用マーク群が形成されている場合には、複数の異なる情報用マーク群に夫々対応する複数の判別用マーク群が形成されてもよい。具体的には、例えば、第１ガイドトラックがセンタートラックとなる複数のガイドトラックの夫々に形成された同一の第１情報用マーク群に対応するように、センタートラックである第１ガイドトラックのトラック中心から左右に所定距離シフトしている一対の第１判別用記録マークを含む第１判別用マーク群が形成される一方で、第１ガイドトラックがセンタートラックとなる複数のガイドトラックの夫々に形成された同一の第２情報用マーク群に対応するように、センタートラックである第１ガイドトラックのトラック中心から左右に所定距離シフトしている一対の第２判別用記録マークを含む第２判別用マーク群が形成されてもよい。或いは、例えば、あるガイドトラックがセンタートラックとなる複数のガイドトラックの夫々に複数の異なる情報用マーク群が形成されている場合には、複数の異なる情報用マーク群に共通して対応する単一の判別用マーク群が形成されてもよい。具体的には、例えば、第１ガイドトラックがセンタートラックとなる複数のガイドトラックの夫々に形成された同一の第１情報用マーク群及び同一の第２情報用マーク群の双方に対応するように、センタートラックである第１ガイドトラックのトラック中心から左右に所定距離シフトしている一対の第１判別用記録マークを含む第１判別用マーク群が形成されてもよい。 Further, it is preferable that the discrimination mark group is formed to be paired with the same information mark group. In this case, for example, when a plurality of different information mark groups are formed in each of a plurality of guide tracks in which a certain guide track is a center track, a plurality of determinations respectively corresponding to the plurality of different information mark groups A mark group may be formed. Specifically, for example, the track of the first guide track that is the center track so that the first guide track corresponds to the same first information mark group formed on each of the plurality of guide tracks that become the center track. A first discriminating mark group including a pair of first discriminating recording marks shifted by a predetermined distance from the center to the right and left is formed, while the first guide track is formed on each of a plurality of guide tracks serving as a center track. Corresponding to the same second information mark group, the second discrimination mark including a pair of second discrimination recording marks shifted by a predetermined distance from the track center of the first guide track as the center track to the left and right. A mark group may be formed. Alternatively, for example, when a plurality of different information mark groups are formed in each of a plurality of guide tracks in which a certain guide track becomes a center track, a single corresponding to a plurality of different information mark groups in common The discriminating mark group may be formed. Specifically, for example, the first guide track corresponds to both the same first information mark group and the same second information mark group formed on each of the plurality of guide tracks serving as the center track. A first discriminating mark group including a pair of first discriminating recording marks shifted by a predetermined distance from the track center of the first guide track which is the center track may be formed.
　本実施形態の記録再生装置は、このような判別用マーク群が形成される本実施形態の記録媒体に対して記録動作及び再生動作の少なくとも一方を行う。具体的には、検出手段は、判別用マーク群に照射されたガイドレーザ光の戻り光から、第１プッシュプル信号を取得する。このとき、ガイドレーザ光のガイド層上におけるビームスポットのスポット中心は、判別用マーク群が形成されているガイドトラック上に位置する。判別手段は、第１プッシュプル信号（つまり、判別用マーク群を構成する複数の一対の判別用記録マークの組み合わせの違いに応じて信号レベルが変化する第１プッシュプル信号）に基づいて、ガイドレーザ光が現在トレースしているガイドトラック（つまり、スポット中心が位置しているガイドトラック）がセンタートラックであるか否かを判別する。このため、本実施形態の記録再生装置によれば、以下に示す利点がある。 The recording / reproducing apparatus of this embodiment performs at least one of a recording operation and a reproducing operation on the recording medium of this embodiment in which such a discrimination mark group is formed. Specifically, the detection means acquires the first push-pull signal from the return light of the guide laser light irradiated to the discrimination mark group. At this time, the spot center of the beam spot on the guide layer of the guide laser beam is located on the guide track on which the discrimination mark group is formed. The discriminating means is based on the first push-pull signal (that is, the first push-pull signal whose signal level changes according to the combination of a plurality of pairs of discriminating recording marks constituting the discriminating mark group). It is determined whether or not the guide track currently traced by the laser beam (that is, the guide track on which the spot center is located) is the center track. For this reason, the recording / reproducing apparatus of this embodiment has the following advantages.
　まず、本実施形態によれば、ガイド層に形成される判別用マーク群は、センタートラックのトラック中心を基準として左右に所定距離シフトしている一対の判別用記録マークが複数組み合わせられたマーク群である。このため、このような判別用マーク群をガイド層に形成したとしても、当該判別用マーク群がプッシュプル信号に及ぼし得る信号レベルの変動の平均値はゼロ（但し、実質的にゼロと同視し得る程度のマージンを含む）となる。従って、判別用マーク群の存在がプッシュプル信号に基づくトラッキング制御に悪影響を及ぼすことは殆ど或いは全くなくなる。従って、記録再生装置は、好適なトラッキング制御を行いながら、複数の記録層に対する記録動作及び再生動作の少なくとも一方を行うことができる。 First, according to the present embodiment, the discrimination mark group formed on the guide layer is a mark group in which a plurality of discrimination record marks that are shifted by a predetermined distance from the center of the center track to the left and right are combined. It is. Therefore, even if such a discrimination mark group is formed on the guide layer, the average value of signal level fluctuations that can be exerted on the push-pull signal by the discrimination mark group is zero (however, it is substantially regarded as zero. Including the margin to obtain). Therefore, the presence of the discrimination mark group has little or no adverse effect on the tracking control based on the push-pull signal. Therefore, the recording / reproducing apparatus can perform at least one of the recording operation and the reproducing operation with respect to the plurality of recording layers while performing suitable tracking control.
　その一方で、判別用マーク群を構成する複数の一対の判別用記録マークの組み合わせの違いに応じて、同一の情報用マーク群が形成されている複数のガイドトラックのうちのセンタートラックを判別することができる。このような複数の一対の判別用記録マークの組み合わせの違いは、プッシュプル信号の信号レベルの変動の瞬時値の変化を監視することで容易に読み取ることができる。従って、本実施形態によれば、プッシュプル信号を用いて読み取ることができる判別用記録マークを、ガイド層に形成することができる。言い換えれば、本実施形態によれば、ＲＦ信号（言い換えれば、総和信号）を用いて読み取らなくともよい判別用記録マークを、ガイド層に形成することができる。従って、記録再生装置は、プッシュプル信号に基づいて、同一の情報用マーク群が形成されている複数のガイドトラックのうちのセンタートラックを判別することができる。その結果、記録再生装置は、ガイド層に予め形成された情報用マーク群に応じたビットデータを好適に読み取りながら、複数の記録層に対する記録動作及び再生動作の少なくとも一方を行うことができる。 On the other hand, the center track of the plurality of guide tracks on which the same information mark group is formed is discriminated according to the difference in the combination of the plurality of pairs of discrimination recording marks constituting the discrimination mark group. be able to. Such a difference in the combination of a plurality of pairs of discriminating recording marks can be easily read by monitoring the change in the instantaneous value of the signal level fluctuation of the push-pull signal. Therefore, according to the present embodiment, the determination recording mark that can be read using the push-pull signal can be formed on the guide layer. In other words, according to the present embodiment, it is possible to form a determination recording mark on the guide layer that does not need to be read using an RF signal (in other words, a total signal). Therefore, the recording / reproducing apparatus can determine the center track among the plurality of guide tracks on which the same information mark group is formed based on the push-pull signal. As a result, the recording / reproducing apparatus can perform at least one of the recording operation and the reproducing operation with respect to the plurality of recording layers while preferably reading the bit data corresponding to the information mark group formed in advance on the guide layer.
　仮に、同一の情報用マーク群が形成されている複数のガイドトラックのうちのセンタートラックを判別することができなければ、以下に示す技術的問題点が生ずる。具体的には、本実施形態では、複数のガイドトラックの夫々に同一の情報用マーク群が形成されるがゆえに、一のガイドトラックをセンタートラックとする複数のガイドトラックの夫々に形成される一の情報用マーク群は、一のガイドトラックに隣接する他のガイドトラックにも形成される。従って、本来は一のガイドトラックにスポット中心を一致させたガイドレーザ光を用いて一の情報用マーク群が読み取られるべきところ、他のガイドトラックにスポット中心を一致させたガイドレーザ光を用いて一の情報用マーク群が読み取られてしまうおそれがある。このとき、例えば情報用マーク群がアドレス情報を示している場合には、アドレス情報の誤検出が発生してしまうおそれがある。つまり、他のガイドトラックにスポット中心を一致させたガイドレーザ光を用いて一の情報用マーク群を読み取った記録再生装置は、他のガイドトラックが一のガイドトラックであると誤って認識してしまうおそれがある。しかるに、本実施形態では、記録再生装置は、同一の情報用マーク群が形成されている複数のガイドトラックのうちのセンタートラックを判別することができる。つまり、記録再生装置は、現在トレースしているガイドトラックがセンタートラックであるか否かを判別することができる。従って、一のガイドトラックをセンタートラックとする複数のガイドトラックの夫々に形成される一の情報用マーク群が、他のガイドトラックにスポット中心を一致させたガイドレーザ光を用いて読み取られるおそれは殆ど又は全くなくなる。従って、上述した技術的問題が発生するおそれは殆ど又は全くなくなる。 If the center track of the plurality of guide tracks on which the same information mark group is formed cannot be discriminated, the following technical problems will occur. Specifically, in the present embodiment, since the same information mark group is formed on each of the plurality of guide tracks, one formed on each of the plurality of guide tracks having one guide track as the center track. This information mark group is also formed on another guide track adjacent to one guide track. Therefore, one information mark group should be read by using a guide laser beam whose spot center coincides with one guide track, but a guide laser beam whose spot center coincides with another guide track. One information mark group may be read. At this time, for example, when the information mark group indicates the address information, there is a risk of erroneous detection of the address information. In other words, a recording / reproducing apparatus that has read one information mark group using a guide laser beam whose spot center coincides with another guide track erroneously recognizes that the other guide track is one guide track. There is a risk that. However, in the present embodiment, the recording / reproducing apparatus can determine the center track among a plurality of guide tracks on which the same information mark group is formed. That is, the recording / reproducing apparatus can determine whether or not the guide track currently being traced is the center track. Therefore, there is a possibility that one information mark group formed on each of a plurality of guide tracks having one guide track as a center track may be read using a guide laser beam whose spot center coincides with another guide track. Little or no. Thus, there is little or no risk of the technical problems described above.
　加えて、本実施形態によれば、一対の判別用記録マークの夫々の幅がガイドトラックの幅の２倍以上となる。従って、記録再生装置は、ガイドレーザ光のフォーカスオフセットの偏差（いわゆる、デフォーカス）に影響を受けることなく、判別用マーク群に応じてセンタートラックを判別することができる。 In addition, according to the present embodiment, the width of each of the pair of discrimination recording marks is at least twice the width of the guide track. Accordingly, the recording / reproducing apparatus can discriminate the center track according to the discrimination mark group without being affected by the focus offset deviation (so-called defocus) of the guide laser beam.
　このように、本実施形態の記録再生装置によれば、ガイド層上の複数のガイドトラックの夫々に記録された情報用マーク群を好適に読み取るために、情報用マーク群が形成された複数のガイドトラックのうちの中心付近に位置するセンタートラックを好適に判別することができる。 As described above, according to the recording / reproducing apparatus of the present embodiment, in order to suitably read the information mark group recorded on each of the plurality of guide tracks on the guide layer, a plurality of information mark groups are formed. A center track located near the center of the guide tracks can be suitably determined.
　＜２＞
　本実施形態の記録再生装置の他の態様では、前記判別手段は、前記判別用マーク群を構成する前記一対の判別用記録マークの組み合わせに応じて変化する前記第１プッシュプル信号の信号レベルに基づいて、前記ガイドレーザ光がトレースしている前記ガイドトラックが前記センタートラックであるか否かを判別する。 <2>
In another aspect of the recording / reproducing apparatus of the present embodiment, the determination means has a signal level of the first push-pull signal that changes according to a combination of the pair of determination recording marks constituting the determination mark group. Based on this, it is determined whether or not the guide track traced by the guide laser beam is the center track.
　この態様によれば、判別手段は、判別用マーク群を構成する一対の判別用記録マークの組み合わせに応じた第１プッシュプル信号の信号レベルの変化に基づいて、ガイドレーザ光がトレースしているガイドトラックがセンタートラックであるか否かを好適に判別することができる。 According to this aspect, the discriminating means traces the guide laser beam based on the change in the signal level of the first push-pull signal according to the combination of the pair of discriminating recording marks constituting the discriminating mark group. Whether or not the guide track is the center track can be suitably determined.
　＜３＞
　本実施形態の記録再生装置の他の態様では、前記判別手段は、前記判別用マーク群を構成する前記一対の判別用記録マークの組み合わせに応じて変化する前記第１プッシュプル信号の信号レベルを、所定の処理単位毎に所定の閾値と比較することで、前記ガイドレーザ光がトレースしている前記ガイドトラックが前記センタートラックであるか否かを判別する。 <3>
In another aspect of the recording / reproducing apparatus of the present embodiment, the determination means determines the signal level of the first push-pull signal that changes according to the combination of the pair of determination recording marks constituting the determination mark group. Then, by comparing with a predetermined threshold value for each predetermined processing unit, it is determined whether or not the guide track traced by the guide laser beam is the center track.
　この態様によれば、判別手段は、所定の処理単位毎の第１プッシュプル信号の信号レベルの変化の態様を比較的容易に特定することができる。その結果、判別手段は、判別用マーク群を構成する一対の判別用記録マークの組み合わせに応じた第１プッシュプル信号の信号レベルの変化に基づいて、ガイドレーザ光がトレースしているガイドトラックがセンタートラックであるか否かを好適に判別することができる。 According to this aspect, the discriminating means can specify the aspect of the change in the signal level of the first push-pull signal for each predetermined processing unit relatively easily. As a result, the discriminating means has the guide track traced by the guide laser beam based on the change in the signal level of the first push-pull signal according to the combination of the pair of discriminating recording marks constituting the discriminating mark group. It can be suitably determined whether or not it is a center track.
　＜４＞
　本実施形態の記録再生装置の他の態様では、前記検出手段は、前記情報用マーク群に照射された前記ガイドレーザ光の戻り光から第２プッシュプル信号を更に検出し、前記第２プッシュプル信号に基づいて、前記判別手段によって前記センタートラックであると判別された前記ガイドトラックが中心付近に位置する前記複数のガイドトラックの夫々に形成されている前記情報用マーク群に応じたビットデータを取得する取得手段と、前記取得手段が取得したビットデータに基づいて、前記複数の記録層に対する前記記録動作及び前記再生動作の少なくとも一方を行う記録再生手段とを更に備える。 <4>
In another aspect of the recording / reproducing apparatus of the present embodiment, the detection means further detects a second push-pull signal from a return light of the guide laser light irradiated to the information mark group, and the second push-pull Based on the signal, bit data corresponding to the information mark group formed on each of the plurality of guide tracks in which the guide track determined to be the center track by the determining means is located near the center. An acquisition means for acquiring, and a recording / reproducing means for performing at least one of the recording operation and the reproducing operation for the plurality of recording layers based on the bit data acquired by the acquiring means are further provided.
　この態様によれば、取得手段は、ガイドレーザ光の戻り光から得られる第２プッシュプル信号に基づいて、情報用マーク群に応じたビットデータ（例えば、後述するように、情報用マーク群を構成する一対の情報用記録マークの組み合わせに応じたビットデータ）を取得することができる。その結果、記録再生手段は、当該ビットデータに基づいて、複数の記録層に対する記録動作及び再生動作の少なくとも一方を行うことができる。 According to this aspect, the acquisition unit obtains the bit data corresponding to the information mark group based on the second push-pull signal obtained from the return light of the guide laser beam (for example, as described later, the information mark group is Bit data corresponding to a combination of a pair of recording marks for information). As a result, the recording / reproducing means can perform at least one of a recording operation and a reproducing operation with respect to the plurality of recording layers based on the bit data.
　特に、この態様では、取得手段は、ガイドレーザ光が照射される全ての情報用マーク群に応じたビットデータを取得することに代えて、センタートラックであると判別されたガイドトラックが中心付近に位置する複数のガイドトラックの夫々に形成された情報用マーク群に応じたビットデータを選択的に取得する。このため、取得手段は、他のガイドトラックにスポット中心を一致させたガイドレーザ光から得られる第２プッシュプル信号に基づいて、一のガイドトラックをセンタートラックとする複数のガイドトラックの夫々に形成される一の情報用マーク群に応じたビットデータを取得するおそれは殆ど又は全くなくなる。従って、上述した技術的問題が発生するおそれは殆ど又は全くなくなる。 In particular, in this aspect, instead of acquiring the bit data corresponding to all the information mark groups irradiated with the guide laser beam, the acquisition unit has the guide track determined to be the center track near the center. Bit data corresponding to the information mark group formed on each of the plurality of guide tracks is selectively acquired. Therefore, the acquisition means is formed on each of a plurality of guide tracks having one guide track as the center track, based on the second push-pull signal obtained from the guide laser beam whose spot center coincides with the other guide tracks. There is little or no risk of acquiring bit data corresponding to one information mark group. Thus, there is little or no risk of the technical problems described above.
　＜５＞
　上述の如くセンタートラックであると判別されたガイドトラックが中心付近に位置する複数のガイドトラックの夫々に形成されている情報用マーク群に応じたビットデータを取得する記録再生装置の態様では、前記取得手段は、前記判別手段によって前記センタートラックであると判別されなかった前記ガイドトラック上に形成されている前記情報用マーク群に応じたビットデータを取得しない。 <5>
In the aspect of the recording / reproducing apparatus for acquiring the bit data corresponding to the information mark group formed on each of the plurality of guide tracks located near the center of the guide track determined to be the center track as described above, The acquisition unit does not acquire bit data corresponding to the information mark group formed on the guide track that is not determined to be the center track by the determination unit.
　この態様によれば、取得手段は、他のガイドトラックにスポット中心を一致させたガイドレーザ光から得られる第２プッシュプル信号に基づいて、一のガイドトラックをセンタートラックとする複数のガイドトラックの夫々に形成される一の情報用マーク群に応じたビットデータを取得するおそれは殆ど又は全くなくなる。言い換えれば、取得手段は、一のガイドトラックにスポット中心を一致させたガイドレーザ光から得られる第２プッシュプル信号に基づかなければ、一のガイドトラックをセンタートラックとする複数のガイドトラックの夫々に形成される一の情報用マーク群に応じたビットデータを取得することはない。従って、上述した技術的問題が発生するおそれは殆ど又は全くなくなる。 According to this aspect, the acquisition unit is configured to detect a plurality of guide tracks having one guide track as the center track based on the second push-pull signal obtained from the guide laser beam having the spot center aligned with another guide track. There is little or no risk of acquiring bit data corresponding to one information mark group formed respectively. In other words, if the acquisition means is not based on the second push-pull signal obtained from the guide laser beam whose spot center is coincident with one guide track, each of the plurality of guide tracks having the one guide track as the center track is provided. Bit data corresponding to one formed information mark group is not acquired. Thus, there is little or no risk of the technical problems described above.
　＜６＞
　上述の如くセンタートラックであると判別されたガイドトラックが中心付近に位置する複数のガイドトラックの夫々に形成されている情報用マーク群に応じたビットデータを取得する記録再生装置の態様では、前記記録再生手段は、(i)前記取得手段が取得した前記ビットデータを所定数だけ蓄積すると共に、(ii)前記所定数だけ蓄積した前記ビットデータに対してまとめて誤り訂正処理することで得られる前記ビットデータに基づいて、前記複数の記録層に対する前記記録動作及び前記再生動作の少なくとも一方を行う。 <6>
In the aspect of the recording / reproducing apparatus for acquiring the bit data corresponding to the information mark group formed on each of the plurality of guide tracks located near the center of the guide track determined to be the center track as described above, The recording / reproducing means is obtained by (i) accumulating a predetermined number of the bit data obtained by the obtaining means, and (ii) performing error correction processing on the bit data accumulated by the predetermined number collectively. Based on the bit data, at least one of the recording operation and the reproducing operation for the plurality of recording layers is performed.
　この態様によれば、記録再生手段は、取得手段が選択的に取得したビットデータ（つまり、センタートラックであると判別されたガイドトラックが中心付近に位置する複数のガイドトラックの夫々に形成された情報用マーク群に応じたビットデータ）に基づいて、記録動作及び再生動作の少なくとも一方を行うことができる。 According to this aspect, the recording / reproducing means is formed on each of the plurality of guide tracks in which the bit data selectively acquired by the acquiring means (that is, the guide track determined to be the center track is located near the center). Based on the bit data corresponding to the information mark group), at least one of the recording operation and the reproducing operation can be performed.
　＜７＞
　上述の如く所定数だけ蓄積したビットデータに対してまとめて誤り訂正処理する記録再生装置の態様では、前記所定数は、ＥＣＣブロックを構成するワードのビット数である。 <7>
As described above, in the aspect of the recording / reproducing apparatus that collectively performs error correction processing on the bit data stored in a predetermined number, the predetermined number is the number of bits of a word constituting the ECC block.
　この態様によれば、取得手段が選択的に取得したビットデータ（つまり、センタートラックであると判別されたガイドトラックが中心付近に位置する複数のガイドトラックの夫々に形成された情報用マーク群に応じたビットデータ）に基づいて、記録動作及び再生動作の少なくとも一方を行うことができる。 According to this aspect, the bit data selectively acquired by the acquisition means (that is, the information mark group formed on each of the plurality of guide tracks in which the guide track determined to be the center track is located near the center) Based on the corresponding bit data), at least one of the recording operation and the reproducing operation can be performed.
　＜８＞
　本実施形態の記録再生装置の他の態様では、前記判別用マーク群は、(i)同一の回転位相位置に形成される前記一対の判別用記録マーク及び(ii)異なる回転位相位置に形成される前記一対の判別用記録マークの少なくとも一方を含んでいる。 <8>
In another aspect of the recording / reproducing apparatus of the present embodiment, the determination mark group is formed at (i) the pair of determination recording marks formed at the same rotational phase position and (ii) at different rotational phase positions. At least one of the pair of discrimination recording marks.
　この態様によれば、一対の判別用記録マークは、センタートラックのトラック中心を基準として左側に所定距離シフトしている記録マークとセンタートラックのトラック中心を基準として右側に所定距離シフトしている記録マークを含む一対の記録マークであって且つ同一の回転位相位置に形成される一対の記録マークであってもよい。或いは、一対の判別用記録マークは、センタートラックのトラック中心を基準として左側に所定距離シフトしている記録マークであって且つ第１の回転位相位置に形成される記録マークとセンタートラックのトラック中心を基準として右側に所定距離シフトしている記録マークを含む一対の記録マークであって且つ第１の回転位相位置とは異なる第２の回転位相位置に形成される記録マークとを含む一対の記録マークであってもよい。 According to this aspect, the pair of determination recording marks is a recording mark shifted to the left by a predetermined distance with respect to the track center of the center track and a recording mark shifted to the right by a predetermined distance with respect to the track center of the center track. It may be a pair of recording marks including marks and a pair of recording marks formed at the same rotational phase position. Alternatively, the pair of determination recording marks is a recording mark shifted to the left by a predetermined distance with respect to the track center of the center track, and is formed at the first rotational phase position and the track center of the center track. A pair of recording marks including a recording mark that includes a recording mark that is shifted to the right by a predetermined distance with respect to the first rotational phase position that is different from the first rotational phase position It may be a mark.
　＜９＞
　上述の如く判別用マーク群が同一の回転位相位置に形成される一対の判別用記録マークを含む記録再生装置の態様では、同一の回転位相位置に形成される前記一対の判別用記録マークは、(i)前記センタートラックにスポット中心が一致するガイドレーザ光を前記一対の判別用記録マークに照射することで得られるプッシュプル信号の信号レベルの絶対値が第１閾値以下となり、且つ(ii)前記情報用マーク群が形成されている前記複数のガイドトラックのうち前記センタートラック以外の他のガイドトラックにスポット中心が一致する前記ガイドレーザ光を前記一対の判別用記録マークに照射することで得られるプッシュプル信号の信号レベルの絶対値が前記第１閾値より大きくなるように形成される。 <9>
In the aspect of the recording / reproducing apparatus including the pair of determination recording marks in which the determination mark group is formed at the same rotational phase position as described above, the pair of determination recording marks formed at the same rotational phase position includes: (i) the absolute value of the signal level of the push-pull signal obtained by irradiating the pair of determination recording marks with guide laser light whose spot center coincides with the center track is equal to or less than a first threshold; and (ii) It is obtained by irradiating the pair of determination recording marks with the guide laser light whose spot center coincides with a guide track other than the center track among the plurality of guide tracks on which the information mark group is formed. The absolute value of the signal level of the push-pull signal to be generated is larger than the first threshold.
　この態様によれば、記録再生装置は、同一の回転位相位置に形成される一対の判別用記録マークから得られるプッシュプル信号の信号レベルを監視することで、センタートラックを好適に判別することができる。 According to this aspect, the recording / reproducing apparatus can appropriately discriminate the center track by monitoring the signal level of the push-pull signal obtained from the pair of discriminating recording marks formed at the same rotational phase position. it can.
　具体的には、この態様では、センタートラックのトラック中心から左右に所定距離シフトしている一対の判別用記録マークが同一の回転位相位置に形成されている。従って、センタートラックにスポット中心が一致するガイドレーザ光が当該一対の判別用記録マークに照射されれば、スポット中心を基準とする一対の判別用記録マークの分布態様が左右対称となる（或いは、左右対称の状態に近づく）。このため、プッシュプル信号の信号レベルは相対的に小さくなる（例えば、ゼロに近づく）。一方で、センタートラック以外のガイドトラックにスポット中心が一致するガイドレーザ光が当該一対の判別用記録マークに照射されれば、スポット中心を基準とする一対の判別用記録マークの分布態様が左右対称ではなくなる（或いは、左右対称の状態から遠ざかる）。このため、プッシュプル信号の信号レベルは相対的に大きくなる。つまり、あるガイドトラックにガイドレーザ光を照射している状態で得られるプッシュプル信号の信号レベルの絶対値が第１閾値以下（或いは、第１閾値未満）であれば、このガイドトラックがセンタートラックである可能性が高いと判別される。一方で、あるガイドトラックにガイドレーザ光を照射している状態で得られるプッシュプル信号の信号レベルの絶対値が第１閾値より大きくなる（或いは、第１閾値以上である）のであれば、このガイドトラックがセンタートラックではない可能性が高いと判別される。 More specifically, in this embodiment, a pair of determination recording marks shifted by a predetermined distance from the center of the center track to the left and right are formed at the same rotational phase position. Therefore, if the pair of determination recording marks is irradiated with the guide laser beam whose spot center coincides with the center track, the distribution mode of the pair of determination recording marks with reference to the spot center becomes symmetrical (or It approaches a symmetrical state). For this reason, the signal level of the push-pull signal becomes relatively small (for example, approaches zero). On the other hand, if a guide laser beam whose spot center coincides with a guide track other than the center track is irradiated to the pair of determination recording marks, the distribution mode of the pair of determination recording marks with reference to the spot center is symmetrical. (Or move away from the symmetrical state). For this reason, the signal level of the push-pull signal becomes relatively high. In other words, if the absolute value of the signal level of the push-pull signal obtained in a state where the guide laser beam is irradiated to a certain guide track, this guide track is the center track. It is determined that there is a high possibility of being. On the other hand, if the absolute value of the signal level of the push-pull signal obtained in a state in which a guide track is irradiated with a guide laser beam is greater than the first threshold (or greater than or equal to the first threshold), this It is determined that there is a high possibility that the guide track is not the center track.
　＜１０＞
　上述の如く判別用マーク群が異なる回転位相位置に形成される一対の判別用記録マークを含む記録再生装置の態様では、異なる回転位相位置に形成される前記一対の判別用記録マークは、前記センタートラックにスポット中心が一致するガイドレーザ光を前記一対の判別用記録マークに照射することで得られるプッシュプル信号の信号レベルの絶対値が第１閾値より大きくなるように形成される。 <10>
In the aspect of the recording / reproducing apparatus including a pair of discrimination recording marks formed at different rotational phase positions as described above, the pair of discrimination recording marks formed at different rotational phase positions is the center. The absolute value of the signal level of the push-pull signal obtained by irradiating the pair of determination recording marks with the guide laser beam whose spot center coincides with the track is formed to be larger than the first threshold value.
　この態様によれば、記録再生装置は、異なる回転位相位置に形成される一対の判別用記録マークから得られるプッシュプル信号の信号レベルを監視することで、センタートラックを好適に判別することができる。 According to this aspect, the recording / reproducing apparatus can suitably discriminate the center track by monitoring the signal level of the push-pull signal obtained from the pair of discrimination recording marks formed at different rotational phase positions. .
　具体的には、この態様では、センタートラックのトラック中心から左右に所定距離シフトしている一対の判別用記録マークが異なる回転位相位置に形成されている。従って、センタートラックにスポット中心が一致するガイドレーザ光が当該一対の判別用記録マークに照射されれば、スポット中心を基準とする一対の判別用記録マークの分布態様が左右対称ではなくなる（或いは、左右対称の状態から遠ざかる）。このため、プッシュプル信号の信号レベルは相対的に大きくなる。つまり、あるガイドトラックにガイドレーザ光を照射している状態で得られるプッシュプル信号の信号レベルの絶対値が第１閾値より大きくなるのであれば、このガイドトラックがセンタートラックである可能性が高いと判別される。 Specifically, in this embodiment, a pair of discrimination recording marks shifted by a predetermined distance from the center of the center track to the left and right are formed at different rotational phase positions. Accordingly, if the pair of determination recording marks is irradiated with the guide laser beam whose spot center coincides with the center track, the distribution mode of the pair of determination recording marks based on the spot center is not symmetrical (or Move away from the symmetrical state). For this reason, the signal level of the push-pull signal becomes relatively high. That is, if the absolute value of the signal level of the push-pull signal obtained in a state where the guide laser beam is irradiated to a certain guide track is greater than the first threshold, it is highly likely that this guide track is the center track. Is determined.
　＜１１＞
　本実施形態の記録再生装置の他の態様では、前記判別用マーク群は、当該判別用マーク群が形成されている複数のガイドトラックの夫々において、(i)当該夫々のガイドトラックにスポット中心が一致するガイドレーザ光を照射することで得られるプッシュプル信号の信号レベルの絶対値が第１閾値より大きくなる第１領域が２つ以上含まれるように、(ii)当該夫々のガイドトラックにスポット中心が一致する前記ガイドレーザ光を照射することで得られる前記プッシュプル信号の信号レベルの絶対値が前記第１閾値よりも小さい第２閾値以下となる第２領域が２つ以上含まれるように、又は(iii)前記第１領域及び前記第２領域が共に１つずつ以上含まれるように形成されている。 <11>
In another aspect of the recording / reproducing apparatus of the present embodiment, the determination mark group includes (i) a spot center in each of the plurality of guide tracks on which the determination mark group is formed. (Ii) Spots on each guide track so that two or more first regions where the absolute value of the signal level of the push-pull signal obtained by irradiating the matching guide laser light is larger than the first threshold value are included. Two or more second regions in which the absolute value of the signal level of the push-pull signal obtained by irradiating the guide laser light having the same center is equal to or smaller than a second threshold value smaller than the first threshold value are included. Or (iii) the first region and the second region are formed so as to include one or more each.
　この態様によれば、後に図面を用いて詳細に説明するように、記録再生装置は、判別用マーク群を構成する複数の一対の判別用記録マークの組み合わせの違いに応じて、同一の情報用マーク群が形成された形成されている複数のガイドトラックのうちのセンタートラックをより好適に判別することができる。 According to this aspect, as will be described in detail later with reference to the drawings, the recording / reproducing apparatus performs the same information processing according to the difference in the combination of a plurality of pairs of determination recording marks constituting the determination mark group. The center track among the plurality of guide tracks formed with the mark group can be more suitably discriminated.
　＜１２＞
　本実施形態の記録再生装置の他の態様では、前記一対の判別用記録マークの夫々の幅は、前記ガイド層に照射されるガイドレーザ光が前記ガイド層上で形成するビームスポットの幅の１／２倍以上になる。 <12>
In another aspect of the recording / reproducing apparatus of the present embodiment, the width of each of the pair of discrimination recording marks is one of the widths of the beam spots formed on the guide layer by the guide laser light applied to the guide layer. / Two or more times.
　この態様によれば、一対の判別用記録マークの夫々の幅がビームスポットの幅の１／２倍以上となる。従って、記録再生装置は、ガイドレーザ光のフォーカスオフセットの偏差（いわゆる、デフォーカス）に影響を受けることなく、判別用マーク群に応じてセンタートラックを判別することができる。 According to this aspect, the width of each of the pair of discrimination recording marks is ½ times or more the width of the beam spot. Accordingly, the recording / reproducing apparatus can discriminate the center track according to the discrimination mark group without being affected by the focus offset deviation (so-called defocus) of the guide laser beam.
　尚、ここで言う「ビームスポットの幅」とは、フォーカスオフセットの状態（例えば、フォーカスオフセットの量）によって変動し得るマージンを考慮したビームスポットの幅を示す趣旨である。 The term “beam spot width” as used herein is intended to indicate the width of the beam spot in consideration of a margin that may vary depending on the focus offset state (for example, the amount of focus offset).
　＜１３＞
　本実施形態の記録再生装置の他の態様では、前記ガイドトラックは、交互に形成されたグルーブトラック及びランドトラックを含み、前記判別用マーク群は、(i)前記情報用マーク群が形成されている前記複数のグルーブトラックのうち中心付近に位置するグルーブセンタートラックを識別するための判別用マーク群として、(i-1)前記グルーブセンタートラックのトラック中心を基準として左右に所定距離シフトしている一対の判別用記録マークであって、且つ(ii-2)夫々の判別用記録マークの幅が前記グルーブトラックの幅の２倍以上となる一対の判別用記録マークを含んでおり、前記判別用マーク群は、(ii)前記情報用マーク群が形成されている前記複数のランドトラックのうち中心付近に位置するランドセンタートラックを識別するための判別用マーク群として、(ii-1)前記ランドセンタートラックのトラック中心を基準として左右に所定距離シフトしている一対の判別用記録マークであって、且つ(ii-2)夫々の判別用記録マークの幅が前記ランドトラックの幅の２倍以上となる一対の判別用記録マークを含んでいる。 <13>
In another aspect of the recording / reproducing apparatus of the present embodiment, the guide track includes alternately formed groove tracks and land tracks, and the determination mark group includes (i) the information mark group is formed. As a discrimination mark group for identifying a groove center track located near the center among the plurality of groove tracks, (i-1) shifted by a predetermined distance from side to side with respect to the track center of the groove center track. A pair of determination recording marks, and (ii-2) a pair of determination recording marks each having a width of at least twice the width of the groove track. The mark group is (ii) an identification for identifying a land center track located near the center among the plurality of land tracks on which the information mark group is formed. (Ii-1) a pair of discriminating recording marks shifted by a predetermined distance from side to side with respect to the track center of the land center track, and (ii-2) each discriminating recording mark Includes a pair of discriminating recording marks whose width is at least twice the width of the land track.
　この態様によれば、グルーブトラックに対応する判別用マーク群とランドトラックに対応する判別用マーク群の双方が形成される。従って、記録再生装置は、グルーブトラックにガイドレーザ光を照射すれば、判別用マーク群を構成する複数の一対の判別用記録マークの組み合わせの違いに応じて、同一の情報用マーク群が形成されている複数のグルーブトラックのうちのグルーブセンタートラックをより好適に判別することができる。同様に、記録再生装置は、ランドトラックにガイドレーザ光を照射すれば、判別用マーク群を構成する複数の一対の判別用記録マークの組み合わせの違いに応じて、同一の情報用マーク群が形成されている複数のランドトラックのうちのランドセンタートラックをより好適に判別することができる。 According to this aspect, both the discrimination mark group corresponding to the groove track and the discrimination mark group corresponding to the land track are formed. Therefore, when the recording / reproducing apparatus irradiates the groove track with the guide laser beam, the same information mark group is formed according to the difference in the combination of the plurality of pairs of determination recording marks constituting the determination mark group. Of the plurality of groove tracks, the groove center track can be discriminated more suitably. Similarly, when the land track is irradiated with the guide laser light, the same information mark group is formed according to the difference in the combination of a plurality of pairs of determination recording marks constituting the determination mark group. Among the plurality of land tracks, the land center track can be discriminated more suitably.
　＜１４＞
　本実施形態の記録再生装置の他の態様では、前記ガイド層に照射されるガイドレーザ光が前記ガイド層上で形成するビームスポットに包含される複数のガイドトラックのうちの少なくとも二つのガイドトラックの夫々の同一の回転位相位置に、当該夫々のガイドトラックのトラック中心を基準として左右に所定距離シフトしている一対の情報用記録マークが組み合わせられた同一の前記情報用マーク群が形成されるように、前記情報用マーク群が前記ガイド層に形成されている。 <14>
In another aspect of the recording / reproducing apparatus of the present embodiment, at least two guide tracks out of a plurality of guide tracks included in a beam spot formed on the guide layer by the guide laser beam irradiated on the guide layer. The same information mark group is formed by combining a pair of information recording marks shifted by a predetermined distance from side to side with respect to the track center of each guide track at the same rotational phase position. In addition, the information mark group is formed on the guide layer.
　この態様によれば、情報用マーク群は、ガイドレーザ光がガイド層上で形成するビームスポットに包含される複数のガイドトラックのうちの少なくとも二つのガイドトラックの夫々の同一回転位相位置に形成される。つまり、同一のビットデータ（例えば、１ビットから数ビットないしは十数ビットのビットデータ）を示す同一の情報用マーク群が、ガイドレーザ光のビームスポットに包含される複数のガイドトラックのうちの少なくとも二つのガイドトラックの夫々に、ガイドトラックの進行方向に対して直交する方向に沿って隣接するように形成されている。このとき、情報用マーク群は、ガイドレーザ光がガイド層上で形成するビームスポットに包含される複数のガイドトラックのうちの少なくとも二つのガイドトラックの夫々に形成される。つまり、同一の情報用マーク群が形成されるガイドトラックの数は、ガイドレーザ光のビームスポットに包含されるガイドトラックの数以下となり且つ２以上となる。 According to this aspect, the information mark group is formed at the same rotational phase position of at least two guide tracks among a plurality of guide tracks included in the beam spot formed by the guide laser beam on the guide layer. The That is, the same information mark group indicating the same bit data (for example, bit data of 1 bit to several bits or a dozen bits) is at least one of a plurality of guide tracks included in the beam spot of the guide laser beam. Each of the two guide tracks is formed so as to be adjacent along a direction orthogonal to the traveling direction of the guide track. At this time, the information mark group is formed on each of at least two guide tracks among a plurality of guide tracks included in the beam spot formed by the guide laser beam on the guide layer. That is, the number of guide tracks on which the same information mark group is formed is equal to or less than the number of guide tracks included in the beam spot of the guide laser beam and equal to or more than two.
　更に、少なくとも二つのガイドトラックの夫々の同一回転位相位置に形成される情報用マーク群は、ガイドトラックのトラック中心を基準として左右に所定距離シフトしている一対の情報用記録マークが組み合わせられたマーク群である。つまり、情報用マーク群は、トラック中心を基準として左側に所定距離シフトしている記録マークとトラック中心を基準として右側に所定距離シフトしている記録マークとを含む一対の情報用記録マークが、任意の態様で組み合わせられたマーク群となる。このような一対の情報用記録マークとして、トラック中心を基準として左側に所定距離シフトしている記録マークとトラック中心を基準として右側に所定距離シフトしている記録マークとがガイドトラックの進行方向に沿ってこの順に配列している一対の情報用記録マークや、トラック中心を基準として右側に所定距離シフトしている記録マークとトラック中心を基準として左側に所定距離シフトしている記録マークとがガイドトラックの進行方向に沿ってこの順に配列している一対の情報用記録マークが一例としてあげられる。従って、情報用マーク群は、このような一対の情報用記録マークが１つだけ組み合わせられたマーク群（つまり、一対の情報用記録マークそのものと一致するマーク群）であってもよいし、このような一対の情報用記録マークが任意の態様で組み合わせられたマーク群であってもよい。或いは、情報用マーク群は、後述するように、このような一対の情報用記録マークとその他の記録マーク（例えば、トラック中心上に位置する記録マーク）とが任意の態様で組み合わせられたマーク群であってもよい。 Further, the information mark group formed at the same rotational phase position of each of the at least two guide tracks is combined with a pair of information recording marks shifted by a predetermined distance from side to side with respect to the track center of the guide track. A group of marks. That is, the information mark group includes a pair of information recording marks including a recording mark shifted to the left by a predetermined distance from the track center and a recording mark shifted by a predetermined distance to the right from the track center. The mark group is combined in any manner. As such a pair of information recording marks, a recording mark shifted by a predetermined distance to the left with respect to the track center and a recording mark shifted by a predetermined distance to the right with respect to the track center are arranged in the traveling direction of the guide track. A pair of information recording marks arranged in this order along the track, a recording mark shifted to the right by a predetermined distance from the track center, and a recording mark shifted to the left by a predetermined distance from the track center An example is a pair of information recording marks arranged in this order along the track traveling direction. Therefore, the information mark group may be a mark group in which only one pair of such information recording marks is combined (that is, a mark group that matches the pair of information recording marks themselves). A mark group in which such a pair of information recording marks is combined in an arbitrary manner may be used. Alternatively, as described later, the information mark group is a mark group in which such a pair of information recording marks and other recording marks (for example, a recording mark located on the center of the track) are combined in an arbitrary manner. It may be.
　より具体的な構成を例示して説明する。例えば、ガイドレーザ光のビームスポットに３本のガイドトラックが包含されるとする。この場合、第ｋ（但し、ｋは１以上の整数）番目のガイドトラック、第ｋ＋１番目のガイドトラック及び第ｋ＋２番目のガイドトラックのうちの少なくとも二つのガイドトラックの同一回転位相位置に、同一の情報用マーク群が形成される。例えば、第ｋ番目のガイドトラックの回転位相位置がｘ（但し、ｘは０≦ｘ≦３６０を満たす実数）°となる位置及び第ｋ＋２番目のガイドトラックの回転位相位置がｘ°となる位置に、同一の情報用マーク群が形成される。より具体的には、例えば、第１番目のガイドトラックの回転位相位置が１０°となる位置及び第３番目のガイドトラックの回転位相位置が１０°となる位置に、トラック中心を基準として左側に所定距離シフトしている記録マークとトラック中心を基準として右側に所定距離シフトしている記録マークとがガイドトラックの進行方向に沿ってこの順に配列している一対の情報用記録マークそのものとなる情報用マーク群が形成されてもよい。他方で、例えば、第４番目のガイドトラックの回転位相位置が６０°となる位置及び第６番目のガイドトラックの回転位相位置が６０°となる位置に、トラック中心を基準として右側に所定距離シフトしている記録マークとトラック中心を基準として左側に所定距離シフトしている記録マークとがガイドトラックの進行方向に沿ってこの順に配列している一対の情報用記録マークそのものとなる情報用マーク群が形成されてもよい。 A more specific configuration will be described as an example. For example, it is assumed that three guide tracks are included in the beam spot of the guide laser beam. In this case, the same rotational phase position of at least two of the kth (where k is an integer equal to or greater than 1) th guide track, the (k + 1) th guide track, and the (k + 2) th guide track have the same rotational phase position. An information mark group is formed. For example, the rotation phase position of the kth guide track is x (where x is a real number satisfying 0 ≦ x ≦ 360) ° and the rotation phase position of the k + 2th guide track is x °. , The same information mark group is formed. More specifically, for example, the position where the rotational phase position of the first guide track is 10 ° and the position where the rotational phase position of the third guide track is 10 ° are set to the left with reference to the track center. Information that is a pair of information recording marks themselves, in which a recording mark shifted by a predetermined distance and a recording mark shifted by a predetermined distance to the right with respect to the track center are arranged in this order along the traveling direction of the guide track A mark group may be formed. On the other hand, for example, the fourth guide track has a rotational phase position of 60 ° and the sixth guide track has a rotational phase position of 60 °. An information mark group consisting of a pair of information recording marks arranged in this order along the advancing direction of the guide track with the recording mark being recorded and the recording mark shifted to the left by a predetermined distance with respect to the track center May be formed.
　尚、ガイド層に形成される情報用マーク群の全てが、上述した一対の情報用記録マークが組み合わせられたマーク群でなくともよい。例えば、ガイド層に形成される情報用マーク群の一部が上述した一対の情報用記録マークそのもの（或いは、上述した一対の情報用記録マークの組み合わせ）となるマーク群である一方で、ガイド層に形成される情報用マーク群の他の一部が上述した一対の情報用記録マークを含まない任意の記録マーク（例えば、トラック中心上に位置する記録マーク）であってもよい。 Note that all of the information mark groups formed on the guide layer may not be a mark group in which the pair of information recording marks described above are combined. For example, a part of the information mark group formed on the guide layer is a mark group that becomes the above-described pair of information recording marks themselves (or a combination of the above-described pair of information recording marks), while the guide layer Another part of the information mark group formed on the recording medium may be an arbitrary recording mark that does not include the pair of information recording marks described above (for example, a recording mark located on the center of the track).
　このような情報用マーク群が形成される本実施形態の記録媒体によれば、以下に示す利点がある。 The recording medium according to this embodiment in which such information mark groups are formed has the following advantages.
　まず、本実施形態によれば、ガイド層に形成される情報用マーク群は、ガイドトラックのトラック中心を基準として左右に所定距離シフトしている一対の情報用記録マークが組み合わせられたマーク群である。このため、このような情報用マーク群をガイド層に形成したとしても、当該情報用マーク群がプッシュプル信号に及ぼし得る信号レベルの変動の平均値はゼロ（但し、実質的にゼロと同視し得る程度のマージンを含む）となる。従って、情報用マーク群の存在がプッシュプル信号に基づくトラッキング制御に悪影響を及ぼすことは殆ど或いは全くなくなる。従って、記録再生装置は、好適なトラッキング制御を行いながら、複数の記録層に対する記録動作及び再生動作の少なくとも一方を行うことができる。 First, according to the present embodiment, the information mark group formed on the guide layer is a mark group in which a pair of information recording marks shifted by a predetermined distance from side to side with respect to the track center of the guide track is combined. is there. For this reason, even if such an information mark group is formed on the guide layer, the average value of signal level fluctuations that can be exerted on the push-pull signal by the information mark group is zero (however, it is substantially regarded as zero. Including the margin to obtain). Therefore, the presence of the information mark group has little or no adverse effect on the tracking control based on the push-pull signal. Therefore, the recording / reproducing apparatus can perform at least one of the recording operation and the reproducing operation with respect to the plurality of recording layers while performing suitable tracking control.
　その一方で、情報用マーク群を構成する一対の情報用記録マークの組み合わせの違いに応じて、情報用マーク群に異なるビットデータを割り当てることで、当該情報用マーク群を用いてビットデータをガイド層に記録することができる。このようなビットデータ（つまり、一対の情報用記録マークの組み合わせの違い）は、プッシュプル信号の信号レベルの変動の瞬時値の変化を監視することで容易に読み取ることができる。従って、本実施形態によれば、プッシュプル信号を用いて読み取ることができるビットデータを、ガイド層に記録することができる。言い換えれば、本実施形態によれば、ＲＦ信号（言い換えれば、総和信号）を用いて読み取らなくともよいビットデータを、ガイド層に記録することができる。従って、記録再生装置は、プッシュプル信号に基づいて、ガイド層に予め形成された情報用マーク群に応じたビットデータを好適に読み取りながら、複数の記録層に対する記録動作及び再生動作の少なくとも一方を行うことができる。 On the other hand, by assigning different bit data to the information mark group according to the difference in the combination of the pair of information recording marks constituting the information mark group, the bit data is guided using the information mark group. Can be recorded in layers. Such bit data (that is, the difference in the combination of a pair of information recording marks) can be easily read by monitoring the change in the instantaneous value of the signal level of the push-pull signal. Therefore, according to the present embodiment, bit data that can be read using a push-pull signal can be recorded on the guide layer. In other words, according to the present embodiment, bit data that does not need to be read using an RF signal (in other words, a sum signal) can be recorded on the guide layer. Therefore, the recording / reproducing apparatus performs at least one of the recording operation and the reproducing operation on the plurality of recording layers while preferably reading the bit data corresponding to the information mark group formed in advance on the guide layer based on the push-pull signal. It can be carried out.
　加えて、本実施形態によれば、ガイドレーザ光のビームスポットに包含される複数のガイドトラックのうちの少なくとも二つのガイドトラックの夫々の同一回転位相位置に同一の情報用マーク群が形成される。従って、後に図面を用いて詳述するように、記録再生装置は、ガイドレーザ光のフォーカスオフセットの偏差（いわゆる、デフォーカス）に影響を受けることなく、情報用マーク群に応じたビットデータを読み取ることができる。 In addition, according to this embodiment, the same information mark group is formed at the same rotational phase position of each of at least two guide tracks included in the beam spot of the guide laser beam. . Therefore, as will be described in detail later with reference to the drawings, the recording / reproducing apparatus reads bit data corresponding to the information mark group without being affected by the focus offset deviation (so-called defocus) of the guide laser beam. be able to.
　このように、本実施形態の記録媒体によれば、トラッキング用のガイドトラックが形成されたガイド層に対して、トラッキング制御に及ぼす影響を抑えながら好適にデータ（例えば、上述のビットデータ等）を記録することができる。 As described above, according to the recording medium of the present embodiment, data (for example, the above-described bit data) is suitably applied to the guide layer on which the tracking guide track is formed while suppressing the influence on the tracking control. Can be recorded.
　＜１５＞
　上述の如く一対の情報用記録マークが組み合わせられた同一の情報用マーク群が形成される記録再生装置の態様では、前記複数のガイドトラックの夫々の同一の回転位相位置に、同一の前記情報用マーク群が形成されている。 <15>
In the aspect of the recording / reproducing apparatus in which the same information mark group in which a pair of information recording marks is combined as described above is formed, the same information mark is provided at the same rotational phase position of each of the plurality of guide tracks. A group of marks is formed.
　この態様によれば、ガイドレーザ光のビームスポットに包含される複数のガイドトラックの夫々の同一の回転位相位置に同一の情報用マーク群が形成される。つまり、ガイドレーザ光のビームスポットに包含される複数のガイドトラックの全ての同一回転位相位置に同一の情報用マーク群が形成される。つまり、同一の情報用マーク群が形成されるガイドトラックの数は、ガイドレーザ光のビームスポットに包含されるガイドトラックの数とほぼ等しい。尚、ここで言う「ほぼ等しい」とは、フォーカスオフセットの状態（例えば、フォーカスオフセットの量）によって変動し得るビームスポットの大きさのマージンを考慮した上で概ね等しいと同視し得る状態を含む趣旨である。従って、後に図面を用いて詳述するように、記録再生装置は、ガイドレーザ光のフォーカスオフセットの偏差（いわゆる、デフォーカス）に影響をより一層受けることなく、情報用マーク群に応じたビットデータを読み取ることができる。 According to this aspect, the same information mark group is formed at the same rotational phase position of each of the plurality of guide tracks included in the beam spot of the guide laser beam. That is, the same information mark group is formed at all the same rotational phase positions of the plurality of guide tracks included in the beam spot of the guide laser beam. That is, the number of guide tracks on which the same information mark group is formed is substantially equal to the number of guide tracks included in the beam spot of the guide laser beam. Note that “substantially equal” as used herein includes a state that can be regarded as being approximately equal in consideration of a margin of the size of a beam spot that may vary depending on the state of focus offset (for example, the amount of focus offset). It is. Therefore, as will be described in detail later with reference to the drawings, the recording / reproducing apparatus is not affected more by the deviation (so-called defocus) of the focus offset of the guide laser beam, and the bit data corresponding to the information mark group. Can be read.
　＜１６＞
　上述の如く一対の情報用記録マークが組み合わせられた同一の情報用マーク群が形成される記録再生装置の態様では、前記ガイドトラックは、交互に形成されたグルーブトラック及びランドトラックを含み、前記ビームスポットに包含される複数のグルーブトラックの夫々の同一位相位置に、当該夫々のグルーブトラックのトラック中心を基準として左右に所定距離シフトしている一対の情報用記録マークが組み合わせられた情報用マーク群が形成されており、前記ビームスポットに包含される複数のランドトラックの夫々の同一位相位置に、当該夫々のランドトラックのトラック中心を基準として左右に所定距離シフトしている一対の情報用記録マークが組み合わせられた情報用マーク群が形成されている。 <16>
In the aspect of the recording / reproducing apparatus in which the same information mark group in which a pair of information recording marks is combined as described above is formed, the guide track includes a groove track and a land track formed alternately, and the beam An information mark group in which a pair of information recording marks that are shifted by a predetermined distance from side to side with respect to the track center of each groove track are combined at the same phase position of each of the plurality of groove tracks included in the spot And a pair of information recording marks that are shifted by a predetermined distance to the left and right with respect to the track center of each land track at the same phase position of each of the plurality of land tracks included in the beam spot. An information mark group is formed by combining.
　この態様によれば、グルーブトラック及びランドトラックの双方に情報用マーク群が形成される。従って、記録再生装置は、グルーブトラック及びランドトラックのいずれかにガイドレーザ光を照射すれば、情報用マーク群に応じたビットデータを読み取ることができる。 According to this aspect, the information mark group is formed on both the groove track and the land track. Therefore, the recording / reproducing apparatus can read the bit data corresponding to the information mark group by irradiating either the groove track or the land track with the guide laser beam.
　＜１７＞
　上述の如く一対の情報用記録マークが組み合わせられた同一の情報用マーク群が形成される記録再生装置の態様では、前記検出手段は、前記情報用マーク群に照射された前記ガイドレーザ光の戻り光から第２プッシュプル信号を更に検出し、前記第２プッシュプル信号に基づいて、前記判別手段によって前記センタートラックであると判別された前記ガイドトラックが中心付近に位置する前記複数のガイドトラックの夫々に形成されている前記情報用マーク群に応じたビットデータを取得する取得手段と、前記取得手段が取得したビットデータに基づいて、前記複数の記録層に対する前記記録動作及び前記再生動作の少なくとも一方を行う記録再生手段とを更に備え、前記取得手段は、前記情報用マーク群を構成する前記一対の情報用記録マークの組み合わせに応じて変化する前記第２プッシュプル信号の信号レベルに基づいて、前記ビットデータを取得する。 <17>
In the aspect of the recording / reproducing apparatus in which the same information mark group in which a pair of information recording marks is combined as described above is formed, the detection means returns the guide laser light irradiated to the information mark group. A second push-pull signal is further detected from the light, and based on the second push-pull signal, the plurality of guide tracks in which the guide track determined to be the center track by the determining unit is located near the center. Acquisition means for acquiring bit data corresponding to the information mark group formed on each of the recording marks, and at least one of the recording operation and the reproduction operation for the plurality of recording layers based on the bit data acquired by the acquisition means; Recording information reproducing means for performing one of the information recording means, wherein the obtaining means comprises the pair of information recording markers constituting the information mark group. Based on the signal level of the second push-pull signal which varies according to the combination of click, to acquire the bit data.
　この態様によれば、取得手段は、ガイドレーザ光の戻り光から得られる第２プッシュプル信号に基づいて、情報用マーク群に応じたビットデータ（例えば、情報用マーク群を構成する一対の情報用記録マークの組み合わせに応じたビットデータ）を取得することができる。その結果、記録再生手段は、当該ビットデータに基づいて、複数の記録層に対する記録動作及び再生動作の少なくとも一方を行うことができる。 According to this aspect, the acquisition means is based on the second push-pull signal obtained from the return light of the guide laser light, and the bit data corresponding to the information mark group (for example, a pair of information constituting the information mark group) Bit data corresponding to the combination of recording marks for use). As a result, the recording / reproducing means can perform at least one of a recording operation and a reproducing operation with respect to the plurality of recording layers based on the bit data.
　特に、この態様では、取得手段は、ガイドレーザ光が照射される全ての情報用マーク群に応じたビットデータを取得することに代えて、センタートラックであると判別されたガイドトラックが中心付近に位置する複数のガイドトラックの夫々に形成された情報用マーク群に応じたビットデータを選択的に取得する。このため、取得手段は、他のガイドトラックにスポット中心を一致させたガイドレーザ光から得られる第２プッシュプル信号に基づいて、一のガイドトラックをセンタートラックとする複数のガイドトラックの夫々に形成される一の情報用マーク群に応じたビットデータを取得するおそれは殆ど又は全くなくなる。従って、上述した技術的問題が発生するおそれは殆ど又は全くなくなる。 In particular, in this aspect, instead of acquiring the bit data corresponding to all the information mark groups irradiated with the guide laser beam, the acquisition unit has the guide track determined to be the center track near the center. Bit data corresponding to the information mark group formed on each of the plurality of guide tracks is selectively acquired. Therefore, the acquisition means is formed on each of a plurality of guide tracks having one guide track as the center track, based on the second push-pull signal obtained from the guide laser beam whose spot center coincides with the other guide tracks. There is little or no risk of acquiring bit data corresponding to one information mark group. Thus, there is little or no risk of the technical problems described above.
　加えて、この態様によれば、取得手段は、情報用マーク群を構成する一対の情報用記録マークの組み合わせに応じた第２プッシュプル信号の信号レベルの変化に基づいて、ビットデータを好適に取得することができる。 In addition, according to this aspect, the acquisition unit preferably uses the bit data based on the change in the signal level of the second push-pull signal according to the combination of the pair of information recording marks constituting the information mark group. Can be acquired.
　（記録再生方法の実施形態）
　＜１８＞
　本実施形態の記録再生方法は、(i-1)トラッキング用のガイドトラックが形成されているガイド層と、(i-2)前記ガイド層上に積層されている複数の記録層とを備える記録媒体であって、(ii)前記ガイド層には、(ii-1)互いに隣接する複数のガイドトラックの夫々に形成される情報用マーク群と、(ii-2)前記情報用マーク群が形成されている前記複数のガイドトラックのうち中心付近に位置するガイドトラックであるセンタートラックを判別するための判別用マーク群とが形成されており、(iii)前記判別用マーク群は、(iii-1)前記センタートラックのトラック中心を基準として左右に所定距離シフトしている一対の判別用記録マークであって、且つ(iii-2)夫々の判別用記録マークの幅が前記ガイドトラックの幅の２倍以上となる一対の判別用記録マークを含んでいる記録媒体に対して記録動作及び再生動作の少なくとも一方を行う記録再生方法であって、前記判別用マーク群に照射された前記ガイドレーザ光の戻り光から第１プッシュプル信号を検出する検出工程と、前記検出工程が検出した前記第１プッシュプル信号に基づいて、前記ガイドレーザ光がトレースしている前記ガイドトラックが前記センタートラックであるか否かを判別する判別工程とを備える。 (Embodiment of recording / reproducing method)
<18>
The recording / reproducing method of the present embodiment includes (i-1) a guide layer in which a guide track for tracking is formed, and (i-2) a recording layer including a plurality of recording layers stacked on the guide layer. (Ii) the guide layer is formed with (ii-1) an information mark group formed on each of a plurality of guide tracks adjacent to each other; and (ii-2) the information mark group is formed. A discriminating mark group for discriminating a center track that is a guide track located near the center of the plurality of guide tracks, and (iii) the discriminating mark group is (iii- 1) a pair of discriminating recording marks shifted by a predetermined distance from side to side with respect to the track center of the center track, and (iii-2) the width of each discriminating recording mark is equal to the width of the guide track Includes a pair of discriminating recording marks that are more than doubled A recording / reproducing method for performing at least one of a recording operation and a reproducing operation on a recording medium, and detecting a first push-pull signal from a return light of the guide laser light irradiated to the discrimination mark group And a determination step of determining whether or not the guide track traced by the guide laser beam is the center track based on the first push-pull signal detected by the detection step.
　本実施形態の記録再生方法によれば、上述した本実施形態の記録再生装置が享受することができる各種効果と同様の効果を好適に享受することができる。 According to the recording / reproducing method of the present embodiment, the same effects as the various effects that can be enjoyed by the recording / reproducing apparatus of the present embodiment described above can be suitably enjoyed.
　尚、上述した本実施形態の記録再生装置が取り得る各種態様に対応して、本実施形態の記録再生方法もまた各種態様をとってもよい。 Incidentally, the recording / reproducing method of the present embodiment may also take various aspects, corresponding to the various aspects that the recording / reproducing apparatus of the present embodiment can take.
　本実施形態のこのような作用及び他の利得は次に説明する実施例から更に明らかにされる。 Such an operation and other advantages of the present embodiment will be further clarified from examples described below.
　以上説明したように、本実施形態の記録再生装置は、検出手段と、判別手段とを備える。本実施形態の記録再生方法は、検出工程と、判別とを備える。従って、ト従って、ガイド層上の複数のガイドトラックの夫々に記録された情報用マーク群を好適に読み取るために、情報用マーク群が形成された複数のガイドトラックのうちの中心付近に位置するセンタートラックを好適に判別することができる記録媒体に対する記録動作及び再生動作の少なくとも一方を行うことができる。 As described above, the recording / reproducing apparatus of the present embodiment includes a detection unit and a determination unit. The recording / reproducing method of this embodiment includes a detection step and discrimination. Therefore, in order to preferably read the information mark group recorded on each of the plurality of guide tracks on the guide layer, the information mark group is positioned near the center of the plurality of guide tracks on which the information mark group is formed. It is possible to perform at least one of a recording operation and a reproducing operation with respect to a recording medium that can appropriately determine the center track.
　以下、図面を参照しながら、実施例について説明する。 Hereinafter, examples will be described with reference to the drawings.
　（１）光ディスクの構成
　はじめに、図１及び図２を参照して、光ディスク１１の構成について説明する。図１は、一枚の光ディスク１１を構成する複数の層を、その積層方向（図１中、上下方向）について相互に間隔をあけて分解することで、各層を見易くしてなる模式的な斜視図である。図２は、光ディスク１１の断面を、ガイドレーザ光ＬＢ１及び記録再生レーザ光ＬＢ２の照射態様と共に示す断面図である。 (1) Configuration of Optical Disc First, the configuration of the optical disc 11 will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic perspective view in which a plurality of layers constituting one optical disk 11 are disassembled at intervals in the stacking direction (vertical direction in FIG. 1) to make each layer easy to see. FIG. FIG. 2 is a cross-sectional view showing a cross section of the optical disc 11 together with the irradiation modes of the guide laser beam LB1 and the recording / reproducing laser beam LB2.
　図１に示すように、光ディスク１１は、単一のガイド層１２と複数の（つまり、２層以上の）記録層１３とを備える。つまり、光ディスク１１は、いわゆるガイド層分離型光ディスクである。 As shown in FIG. 1, the optical disc 11 includes a single guide layer 12 and a plurality of (that is, two or more) recording layers 13. That is, the optical disk 11 is a so-called guide layer separation type optical disk.
　光ディスク１１に対する記録動作（特に、所望の記録層１３に対する記録動作）が行われる場合には、ガイド層１２に集光されるトラッキング用のガイドレーザ光ＬＢ１と、複数の記録層１３の夫々に集光される記録再生レーザ光ＬＢ２とが、記録再生装置１００から同時に照射される。一方で、光ディスク１１に対する再生動作（特に、所望の記録層１３に対する再生動作）が行われる場合にもまた、ガイドレーザ光ＬＢ１と記録再生レーザ光ＬＢ２とが、記録再生装置１００から同時に照射される。但し、光ディスク１１に対する再生動作が行われる場合には、記録再生レーザ光ＬＢ２が、トラッキング用に用いられてもよい（つまり、ガイドレーザ光ＬＢ１が用いられなくともよい）。 When a recording operation on the optical disc 11 (particularly, a recording operation on a desired recording layer 13) is performed, the tracking guide laser beam LB1 focused on the guide layer 12 and the plurality of recording layers 13 are collected. The recording / reproducing laser beam LB2 emitted is simultaneously irradiated from the recording / reproducing apparatus 100. On the other hand, also when a reproducing operation on the optical disc 11 (particularly, a reproducing operation on a desired recording layer 13) is performed, the guide laser beam LB1 and the recording / reproducing laser beam LB2 are simultaneously irradiated from the recording / reproducing apparatus 100. . However, when a reproducing operation is performed on the optical disc 11, the recording / reproducing laser beam LB2 may be used for tracking (that is, the guide laser beam LB1 may not be used).
　光ディスク１１はＣＬＶ方式を採用することが好ましい。同心円状又は螺旋状のガイドトラックＴＲ（具体的には、後述するグルーブトラックＧＴ及びランドトラックＬＴ）には、ＣＬＶ方式に準拠して、プリフォーマット情報（例えば、クロック情報やアドレス情報や記録開始タイミング情報等）が予め記録されている。本実施例では、このようなプリフォーマット情報は、トラック中心を基準として左右に等距離シフトしている一対の情報用記録マークＭＬ１及びＭＲ１（図３及び図５参照）が組み合わせられた情報用マーク群ＭＧ１（図４及び図６参照）を用いて記録されている。このような情報用マーク群ＭＧ１は、光ディスク１１の製造時に予めガイド層１２（言い換えれば、ガイド層１２が備えるガイドトラックＴＲ）に形成されることが好ましい。尚、一対の情報用記録マークＭＬ１及びＭＲ１が組み合わせられた情報用マーク群ＭＧ１については、図３以降の図面を参照しながら、後に詳述する。 The optical disk 11 preferably adopts the CLV method. For concentric or spiral guide tracks TR (specifically, a groove track GT and a land track LT described later), preformat information (for example, clock information, address information, recording start timing, etc.) conforms to the CLV system. Information etc.) is recorded in advance. In the present embodiment, such preformat information includes an information mark formed by combining a pair of information recording marks ML1 and MR1 (see FIGS. 3 and 5) that are shifted equidistantly from side to side with respect to the track center. Recorded using group MG1 (see FIGS. 4 and 6). Such an information mark group MG1 is preferably formed in advance on the guide layer 12 (in other words, the guide track TR included in the guide layer 12) when the optical disc 11 is manufactured. The information mark group MG1 in which the pair of information recording marks ML1 and MR1 are combined will be described in detail later with reference to the drawings after FIG.
　加えて、ガイドトラックＴＲ（具体的には、後述するグルーブトラックＧＴ及びランドトラックＬＴ）には、同一の情報用マーク群ＭＧ１が形成されている複数のガイドトラックＴＲのうちの中心に最も近いガイドトラックＴＲであるセンタートラックＣＴを判別するための判別用マーク群ＭＧ２が形成されている。本実施例では、このような判別用マーク群ＭＧ２は、センタートラックＣＴのトラック中心を基準として左右に等距離シフトしている一対の判別用記録マークＭＬ２及びＭＲ２（図７から図８及び図１０から図１１参照）を複数含んでいる。このような判別用マーク群ＭＧ２は、光ディスク１１の製造時に予めガイド層１２（言い換えれば、ガイド層１２が備えるガイドトラックＴＲ）に形成されることが好ましい。尚、一対の判別用記録マークＭＬ２及びＭＲ２が組み合わせられた判別用マーク群ＭＧ２については、図３以降の図面を参照しながら、後に詳述する。 In addition, the guide track TR (specifically, a groove track GT and a land track LT described later) is the guide closest to the center of the plurality of guide tracks TR in which the same information mark group MG1 is formed. A discrimination mark group MG2 for discriminating the center track CT which is the track TR is formed. In this embodiment, such a discrimination mark group MG2 includes a pair of discrimination recording marks ML2 and MR2 (FIGS. 7 to 8 and FIG. 10) that are shifted equidistant from side to side with respect to the track center of the center track CT. To FIG. 11). Such a discrimination mark group MG2 is preferably formed in advance on the guide layer 12 (in other words, the guide track TR included in the guide layer 12) when the optical disc 11 is manufactured. Note that the discrimination mark group MG2 in which the pair of discrimination recording marks ML2 and MR2 are combined will be described in detail later with reference to FIGS.
　尚、ガイド層１２に形成されているガイドトラックＴＲは、シングルスパイラルであってもよい。この場合、グルーブトラックＧＴは、ガイド層１２の所定の領域でランドトラックＬＴに切り替わることが好ましい。同様に、ランドトラックＬＴは、ガイド層１２の所定の領域でグルーブトラックＧＴに切り替わることが好ましい。但し、ガイドトラックＴＲは、グルーブトラックＧＴとランドトラックＬＴとが分離しているダブルスパイラルであってもよい。 The guide track TR formed on the guide layer 12 may be a single spiral. In this case, the groove track GT is preferably switched to the land track LT in a predetermined region of the guide layer 12. Similarly, the land track LT is preferably switched to the groove track GT in a predetermined region of the guide layer 12. However, the guide track TR may be a double spiral in which the groove track GT and the land track LT are separated.
　図２に示すように、記録再生レーザ光ＬＢ２は、ガイド層１２上に積層された複数の記録層１３のうち記録対象又は再生対象たる一つの所望の記録層１３に集光される。記録再生レーザ光ＬＢ２は、例えばＢＤ（Ｂｌｕ－ｒａｙ　Ｄｉｓｃ：ブルーレイディスク）と同じく比較的短波長の青色レーザビームである。一方で、ガイドレーザ光ＬＢ１は、例えばＤＶＤと同じく比較的長波長の赤色レーザビームである。ガイドレーザ光ＬＢ１によりガイド層１２上に形成されるビームスポットの直径は、記録再生レーザ光ＬＢ２により記録層１３上に形成されるビームスポットの直径と比べて、例えば数倍程度となる。 As shown in FIG. 2, the recording / reproducing laser beam LB2 is focused on one desired recording layer 13 to be recorded or reproduced among the plurality of recording layers 13 stacked on the guide layer 12. The recording / reproducing laser beam LB2 is a blue laser beam having a relatively short wavelength as in, for example, BD (Blu-ray Disc: Blu-ray Disc). On the other hand, the guide laser beam LB1 is a red laser beam having a relatively long wavelength as in the case of DVD, for example. The diameter of the beam spot formed on the guide layer 12 by the guide laser beam LB1 is, for example, about several times the diameter of the beam spot formed on the recording layer 13 by the recording / reproducing laser beam LB2.
　複数の記録層１３の夫々は、独立して記録情報を光学的に記録及び再生可能な記録層である。より具体的には、複数の記録層１３は夫々、例えば、２光子吸収材料を含む半透明の薄膜から構成される。例えば、２光子吸収材料としては、２光子吸収が起こった領域の蛍光強度が変化する蛍光物質を用いる蛍光タイプ、電子の局在化によって屈折率が変化するフォトリフラクティブ物質を用いる屈折率変化タイプなどが、採用可能である。屈折率変化タイプの２光子吸収材料としては、フォトクロミック化合物やビス（アラルキリデン）シクロアルカノン化合物などの利用が有望視されている。 Each of the plurality of recording layers 13 is a recording layer capable of optically recording and reproducing recording information independently. More specifically, each of the plurality of recording layers 13 is composed of, for example, a translucent thin film containing a two-photon absorption material. For example, as a two-photon absorption material, a fluorescent type using a fluorescent material in which the fluorescence intensity in a region where two-photon absorption occurs is changed, a refractive index changing type using a photorefractive material in which the refractive index is changed by electron localization, etc. However, it can be adopted. The use of photochromic compounds, bis (aralkylidene) cycloalkanone compounds, etc. is promising as refractive index changing type two-photon absorption materials.
　２光子吸収材料を利用した光ディスク構造としては、(i)光ディスク１１の全体が２光子吸収材料からなるバルク型と、(ii)２光子吸収材料の記録層及び別の透明材料のスペーサ層を交互に積層した層構造型とが存在する。層構造型は、記録層１３とスペーサ層との間の界面で反射される光を利用してフォーカス制御が可能となる利点がある。バルク型は、多層成膜工程が少なく、製造コストを抑えられる利点がある。 As an optical disk structure using a two-photon absorption material, (i) a bulk type in which the entire optical disk 11 is made of a two-photon absorption material, and (ii) a recording layer of a two-photon absorption material and a spacer layer of another transparent material are alternated. There is a layer structure type laminated on the substrate. The layer structure type has an advantage that focus control can be performed using light reflected at the interface between the recording layer 13 and the spacer layer. The bulk type has an advantage that the manufacturing cost can be suppressed because there are few multilayer film forming steps.
　複数の記録層１３は夫々、上述の２光子吸収材料、相変化材料以外にも、例えば色素材料等であってもよい。複数の記録層１３には夫々、未記録状態では、ガイドトラックＴＲは予め形成されておらず、例えば全域が鏡面或いは凹凸のない平面である。 Each of the plurality of recording layers 13 may be, for example, a dye material in addition to the above-described two-photon absorption material and phase change material. In each of the plurality of recording layers 13, the guide track TR is not formed in advance in an unrecorded state, and for example, the entire region is a mirror surface or a flat surface without unevenness.
　尚、以下の説明では、説明の便宜上、グルーブトラックＧＴ及びランドトラックＬＴがストレート構造を有する例を示す。しかしながら、グルーブトラックＧＴ及びランドトラックＬＴには、ウォブリングが適宜に施されていてよい。例えば、グルーブトラックＧＴ又はランドトラックＬＴは夫々、例えば光反射性の材料からなる反射膜が、凹凸溝が形成された基材としての透明膜上に成膜され、更に保護膜としての透明又は不透明な膜で埋められることで形成されてよい。このようなグルーブトラックＧＴやランドトラックＬＴの側壁に、ウォブリングが施されていてよい。 In the following description, for convenience of explanation, an example in which the groove track GT and the land track LT have a straight structure is shown. However, the wobbling may be appropriately performed on the groove track GT and the land track LT. For example, in each of the groove track GT and the land track LT, a reflective film made of, for example, a light-reflective material is formed on a transparent film as a substrate on which concave and convex grooves are formed, and is further transparent or opaque as a protective film. It may be formed by being filled with an appropriate film. Wobbling may be performed on the side walls of the groove track GT and the land track LT.
　（２）ガイド層に形成される情報用マーク群及び判別用マーク群の構成
　続いて、図３から図１２を参照して、ガイド層１２に形成される情報用マーク群ＭＧ１（つまり、ガイドトラックＴＲのトラック中心を基準として左右に等距離シフトしている一対の情報用記録マークＭＬ１及びＭＲ１が組み合わせられた情報用マーク群ＭＧ１）及び判別用マーク群ＭＧ２（つまり、センタートラックＣＴのトラック中心を基準として左右に等距離シフトしている一対の判別用記録マークＭＬ２及びＭＲ２が組み合わせられた判別用マーク群ＭＧ２）の構成について説明する。 (2) Configuration of Information Mark Group and Discrimination Mark Group Formed on Guide Layer Next, referring to FIGS. 3 to 12, information mark group MG1 (that is, guide track) formed on guide layer 12 An information mark group MG1 in which a pair of information recording marks ML1 and MR1 are shifted equidistant from side to side with respect to the TR track center as a reference, and a discrimination mark group MG2 (that is, the track center of the center track CT). A configuration of a discrimination mark group MG2) in which a pair of discrimination recording marks ML2 and MR2 shifted equidistantly from side to side as a reference will be described.
　（２－１）情報用マーク群の構成
　はじめに、図３から図６を参照して、ガイド層１２に形成される情報用マーク群ＭＧ１について説明する。 (2-1) Configuration of Information Mark Group First, the information mark group MG1 formed on the guide layer 12 will be described with reference to FIGS.
　（２－１－１）グルーブトラックに形成される情報用マーク群の構成
　はじめに、図３及び図４を参照して、情報用マーク群ＭＧ１のうちグルーブトラックＧＴに形成される情報用マーク群ＭＧ１の構成について説明する。図３は、グルーブトラックＧＴに形成される情報用マーク群ＭＧ１を構成する一対の情報用記録マークＭＬ１及びＭＲ１の構成を示す平面図である。図４は、グルーブトラックＧＴに形成される情報用マーク群ＭＧ１によって多種類のデータ（具体的には、ビットデータ及び同期データ）が記録される態様を示す平面図である。 (2-1-1) Configuration of Information Mark Group Formed on Groove Track First, referring to FIGS. 3 and 4, the information mark group MG1 formed on the groove track GT of the information mark group MG1 The configuration of will be described. FIG. 3 is a plan view showing the configuration of a pair of information recording marks ML1 and MR1 constituting the information mark group MG1 formed on the groove track GT. FIG. 4 is a plan view showing an aspect in which various types of data (specifically, bit data and synchronization data) are recorded by the information mark group MG1 formed on the groove track GT.
　図３に示すように、グルーブトラックＧＴには、当該グルーブトラックＧＴのトラック中心を基準として左右に等距離シフトした一対の情報用記録マークＭＬ１及びＭＲ１が形成されている。より具体的には、グルーブトラックＧＴには、(i)グルーブトラックＧＴのトラック中心を基準として左側（例えば、グルーブトラックＧＴの進行方向に対して左側）に所定距離だけシフトした情報用記録マークＭＬ１と、(ii)グルーブトラックＧＴのトラック中心を基準として右側（例えば、グルーブトラックＧＴの進行方向に対して右側）に所定距離だけシフトした情報用記録マークＭＲ１が形成されている。 As shown in FIG. 3, the groove track GT is formed with a pair of information recording marks ML1 and MR1 that are shifted equidistant from side to side with respect to the track center of the groove track GT. More specifically, the groove track GT includes (i) an information recording mark ML1 shifted by a predetermined distance to the left side (for example, the left side with respect to the traveling direction of the groove track GT) with respect to the track center of the groove track GT. (Ii) An information recording mark MR1 shifted by a predetermined distance to the right side (for example, right side with respect to the traveling direction of the groove track GT) with respect to the track center of the groove track GT is formed.
　グルーブトラックＧＴに形成される情報用マーク群ＭＧ１は、このような一対の情報用記録マークＭＬ１及びＭＲ１から構成される。例えば、図３は、グルーブトラックＧＴに形成される情報用マーク群ＭＧ１が、一対の情報用記録マークＭＬ１及びＭＲ１そのものである（つまり、ただ一つの一対の情報用記録マークＭＬ１及びＭＲ１が組み合わせられた）情報用マーク群ＭＧ１である例を示している。但し、後の図４（ａ）から図４（ｃ）等を参照して説明するように、グルーブトラックＧＴに形成される情報用マーク群ＭＧ１は、一対の情報用記録マークＭＬ１及びＭＲ１が複数組み合わせられた情報用マーク群ＭＧ１であってもよいし、一又は複数の一対の情報用記録マークＭＬ１及びＭＲ１と一又は複数のその他の記録マーク（例えば、情報用記録マークの中心がトラック中心上に位置する他の情報用記録マークＭＣ１（図４（ａ）参照）若しくは情報用記録マークが形成されない領域（図６（ａ）参照））とが組み合わせられた情報用マーク群ＭＧ１であってもよい。 The information mark group MG1 formed on the groove track GT is composed of such a pair of information recording marks ML1 and MR1. For example, in FIG. 3, the information mark group MG1 formed on the groove track GT is a pair of information recording marks ML1 and MR1 itself (that is, only one pair of information recording marks ML1 and MR1 are combined. An example of the information mark group MG1 is shown. However, as will be described later with reference to FIGS. 4A to 4C, the information mark group MG1 formed on the groove track GT has a plurality of information recording marks ML1 and MR1. The information mark group MG1 may be combined, or one or more pairs of information recording marks ML1 and MR1 and one or more other recording marks (for example, the center of the information recording mark may be on the track center). Even when the information mark group MG1 is combined with another information recording mark MC1 (see FIG. 4A) or an area where the information recording mark is not formed (see FIG. 6A) positioned at Good.
　本実施例では、同一の情報用マーク群ＭＧ１は、複数のグルーブトラックＧＴの夫々の同一の回転位相位置（言い換えれば、同一の回転角度位置）に形成される。つまり、同一の情報用マーク群ＭＧ１は、グルーブトラックＧＴの進行方向（図３中の左側から右側に向かう方向）に対して直交する方向（つまり、図３の上下方向）に沿って相隣接する又は配列するように、複数のグルーブトラックＧＴの夫々に形成される。図３は、３つのグルーブトラックＧＴ（つまり、トラック番号が「ｋ－２」となるグルーブトラックＧＴ、トラック番号が「ｋ」となるグルーブトラックＧＴ及びトラック番号が「ｋ＋２」となるグルーブトラックＧＴ）の夫々の同一の回転位相位置に、情報用記録マークＭＬ１と情報用記録マークＭＲ１とがグルーブトラックＧＴの進行方向に沿ってこの順に配列されている情報用マーク群ＭＧ１が形成される例を示している。 In the present embodiment, the same information mark group MG1 is formed at the same rotational phase position (in other words, the same rotational angle position) of each of the plurality of groove tracks GT. That is, the same information mark group MG1 is adjacent to each other along a direction (that is, a vertical direction in FIG. 3) orthogonal to the traveling direction of the groove track GT (the direction from the left side to the right side in FIG. 3). Alternatively, it is formed on each of the plurality of groove tracks GT so as to be arranged. FIG. 3 shows three groove tracks GT (that is, a groove track GT with a track number “k-2”, a groove track GT with a track number “k”, and a groove track GT with a track number “k + 2”). An information mark group MG1 in which the information recording mark ML1 and the information recording mark MR1 are arranged in this order along the traveling direction of the groove track GT is formed at the same rotational phase position. ing.
　特に、同一の情報用マーク群ＭＧ１は、ガイドレーザ光ＬＢ１のビームスポット（つまり、ガイド層１２上でのビームスポット）に包含されることになる複数のグルーブトラックＧＴの夫々の同一回転位相位置に形成される。言い換えれば、同一の情報用マーク群ＭＧ１が同一の回転位相位置に形成されることになる複数のグルーブトラックＧＴの数は、ガイドレーザ光ＬＢ１のビームスポットに包含されるグルーブトラックＧＴの数とほぼ同一になる。図３は、ガイドレーザ光ＬＢ１のビームスポットに包含されることになる複数のグルーブトラックＧＴの数が「３本」である例を示している。従って、図３は、３つのグルーブトラックＧＴの夫々の同一の回転位相位置に、同一の情報用マーク群ＭＧ１（つまり、情報用記録マークＭＬ１と情報用記録マークＭＲ１とがグルーブトラックＧＴの進行方向に沿ってこの順に配列されている情報用マーク群ＭＧ１）が形成される例を示している。 In particular, the same information mark group MG1 is at the same rotational phase position of each of the plurality of groove tracks GT to be included in the beam spot of the guide laser beam LB1 (that is, the beam spot on the guide layer 12). It is formed. In other words, the number of the plurality of groove tracks GT in which the same information mark group MG1 is formed at the same rotational phase position is almost the same as the number of the groove tracks GT included in the beam spot of the guide laser beam LB1. Be the same. FIG. 3 shows an example in which the number of the plurality of groove tracks GT to be included in the beam spot of the guide laser beam LB1 is “3”. Therefore, FIG. 3 shows that the same information mark group MG1 (that is, the information recording mark ML1 and the information recording mark MR1 travel in the traveling direction of the groove track GT) at the same rotational phase position of each of the three groove tracks GT. The information mark group MG1) arranged in this order is formed.
　尚、図３は、グルーブトラックＧＴの進行方向に沿って、情報用記録マークＭＬ１と情報用記録マークＭＲ１とがこの順に配列されている情報用マーク群ＭＧ１の例を示している。しかしながら、グルーブトラックＧＴの進行方向に沿って、情報用記録マークＭＲ１と情報用記録マークＭＬ１とがこの順に配列されている情報用マーク群ＭＧ１が用いられてもよい。 FIG. 3 shows an example of the information mark group MG1 in which the information recording mark ML1 and the information recording mark MR1 are arranged in this order along the traveling direction of the groove track GT. However, the information mark group MG1 in which the information recording marks MR1 and the information recording marks ML1 are arranged in this order along the traveling direction of the groove track GT may be used.
　また、図３では、周囲と比較して凹部となっている箇所がハッチングで示されている。一方で、周囲と比較して凸部となっている箇所が空白（白色）で示されている。従って、本実施例の光ディスク１１では、グルーブトラックＧＴが凹部となり且つランドトラックＬＴが凸部となると共に、情報用記録マークＭＬ１及びＭＲ１が凹部となる例を示している。但し、グルーブトラックＧＴが凸部となり且つランドトラックＬＴが凹部となると共に、情報用記録マークＭＬ１及びＭＲ１が凸部となっていてもよい。 Moreover, in FIG. 3, the location which is a recessed part compared with the periphery is shown by hatching. On the other hand, a portion that is a convex portion compared with the surroundings is indicated by a blank (white). Therefore, in the optical disk 11 of the present embodiment, an example is shown in which the groove track GT becomes a concave portion and the land track LT becomes a convex portion, and the information recording marks ML1 and MR1 become concave portions. However, the groove track GT may be a convex portion and the land track LT may be a concave portion, and the information recording marks ML1 and MR1 may be convex portions.
　本実施例では、このような情報用マーク群ＭＧ１を用いて、プリフォーマット情報（例えば、クロック情報やアドレス情報や記録開始タイミング情報等）がガイド層１２に（特に、グルーブトラックＧＴに）予め記録されている。より具体的には、本実施例では、同一の回転位相位置に形成される同一の情報用マーク群ＭＧを用いて、プリフォーマット情報の一部を構成するビットデータがガイド層１２に予め記録されている。従って、ガイド層１２の複数箇所に形成された複数の異なる情報用マーク群ＭＧ１から得られるビットデータを組み合わせる（言い換えれば、統合する）ことで、一つのプリフォーマット情報が得られる。更に、本実施例では、このような情報用マーク群ＭＧ１を用いて、プリフォーマット情報の少なくとも一部を構成するビットデータを読み取るときの同期をとるための同期データがガイド層１２に記録される。但し、プリフォーマット情報の少なくとも一部を構成するビットデータや同期データに限らず、情報用マーク群ＭＧ１を用いて、任意のデータがガイド層１２に予め記録されていてもよい。 In this embodiment, preformat information (for example, clock information, address information, recording start timing information, etc.) is recorded in advance on the guide layer 12 (particularly on the groove track GT) using such an information mark group MG1. Has been. More specifically, in this embodiment, bit data constituting a part of the preformat information is recorded in advance on the guide layer 12 using the same information mark group MG formed at the same rotational phase position. ing. Therefore, one preformat information can be obtained by combining (in other words, integrating) bit data obtained from a plurality of different information mark groups MG1 formed at a plurality of locations on the guide layer 12. Further, in the present embodiment, using such information mark group MG1, synchronization data for synchronization when reading bit data constituting at least part of the preformat information is recorded in the guide layer 12. . However, it is not limited to the bit data and synchronization data constituting at least a part of the preformat information, and arbitrary data may be recorded in advance on the guide layer 12 using the information mark group MG1.
　具体的には、図４（ａ）に示すように、トラック中心上に位置する情報用記録マークＭＣ１と、トラック中心を基準として左側に所定距離シフトしている情報用記録マークＭＬ１と、トラック中心上に位置する情報用記録マークＭＣ１と、トラック中心を基準として右側に所定距離シフトしている情報用記録マークＭＲ１とが、グルーブトラックＧＴの進行方向に沿ってこの順に配列されている情報用マーク群ＭＧ１が、同期データを構成する情報用マーク群ＭＧ１として、グルーブトラックＧＴに形成されてもよい。尚、図４（ａ）は、情報用記録マークＭＣ１、情報用記録マークＭＬ１及び情報用記録マークＭＲ１の夫々の長さ（具体的には、グルーブトラックＧＴの進行方向に沿った長さ）が、全て「ａ」となる例を示している。 Specifically, as shown in FIG. 4A, the information recording mark MC1 located on the track center, the information recording mark ML1 shifted to the left by a predetermined distance from the track center, and the track center The information recording mark MC1 positioned above and the information recording mark MR1 shifted to the right by a predetermined distance from the track center are arranged in this order along the traveling direction of the groove track GT. The group MG1 may be formed on the groove track GT as the information mark group MG1 constituting the synchronization data. In FIG. 4A, the length of each of the information recording mark MC1, the information recording mark ML1, and the information recording mark MR1 (specifically, the length along the traveling direction of the groove track GT) is shown. , All show “a”.
　この場合、図４（ａ）に示す情報用マーク群ＭＧ１が形成されたグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、情報用記録マークＭＣ１、情報用記録マークＭＬ１、情報用記録マークＭＣ１及び情報用記録マークＭＲ１がこの順に読み取られることに起因して、「０」、「＋（ハイ）」、「０」及び「－（ロー）」と変化する（但し、ガイドレーザ光ＬＢ１のビームスポットのスポット中心がグルーブトラックＧＴのトラック中心から左側にずれた状態が、プッシュプル信号の極性がマイナスになる状態に相当すると仮定している）。従って、信号レベルが「０」、「＋」、「０」及び「－」の順に変化するプッシュプル信号から、同期データが読み取られる。 In this case, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 tracing the groove track GT on which the information mark group MG1 shown in FIG. 4A is formed is the information recording mark MC1, Due to the fact that the information recording mark ML1, the information recording mark MC1, and the information recording mark MR1 are read in this order, “0”, “+ (high)”, “0”, and “− (low)”. However, the state where the spot center of the beam spot of the guide laser beam LB1 is shifted to the left from the track center of the groove track GT is assumed to correspond to a state where the polarity of the push-pull signal is negative. Therefore, the synchronization data is read from the push-pull signal whose signal level changes in the order of “0”, “+”, “0”, and “−”.
　図４（ｂ）に示すように、トラック中心上に位置する情報用記録マークＭＣ１と、トラック中心を基準として右側に所定距離シフトしている情報用記録マークＭＲ１と、トラック中心を基準として左側に所定距離シフトしている情報用記録マークＭＬ１と、トラック中心上に位置する情報用記録マークＭＣ１とが、グルーブトラックＧＴの進行方向に沿ってこの順に配列されている情報用マーク群ＭＧ１が、ビットデータ（ビット０）を構成する情報用マーク群ＭＧ１として、グルーブトラックＧＴに形成されてもよい。尚、図４（ｂ）は、情報用記録マークＭＣ１、情報用記録マークＭＬ１及び情報用記録マークＭＲ１の夫々の長さが、全て「ａ」となる例を示している。 As shown in FIG. 4B, the information recording mark MC1 located on the track center, the information recording mark MR1 shifted by a predetermined distance to the right with respect to the track center, and the left with respect to the track center. An information mark group MG1 in which an information recording mark ML1 shifted by a predetermined distance and an information recording mark MC1 located on the center of the track are arranged in this order along the traveling direction of the groove track GT is a bit. The information mark group MG1 constituting the data (bit 0) may be formed on the groove track GT. FIG. 4B shows an example in which the lengths of the information recording mark MC1, the information recording mark ML1, and the information recording mark MR1 are all “a”.
　この場合、図４（ｂ）に示す情報用マーク群ＭＧ１が形成されたグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、情報用記録マークＭＣ１、情報用記録マークＭＲ１、情報用記録マークＭＬ１及び情報用記録マークＭＣ１がこの順に読み取られることに起因して、「０」、「－」、「＋」及び「０」と変化する。従って、信号レベルが「０」、「－」、「＋」及び「０」の順に変化するプッシュプル信号から、ビットデータ（ビット０）が読み取られる。 In this case, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 tracing the groove track GT on which the information mark group MG1 shown in FIG. 4B is formed is the information recording mark MC1, Due to the fact that the information recording mark MR1, the information recording mark ML1, and the information recording mark MC1 are read in this order, they change to “0”, “−”, “+”, and “0”. Therefore, bit data (bit 0) is read from a push-pull signal whose signal level changes in the order of “0”, “−”, “+”, and “0”.
　図４（ｃ）に示すように、トラック中心上に位置する情報用記録マークＭＣ１と、トラック中心を基準として左側に所定距離シフトしている情報用記録マークＭＬ１と、トラック中心を基準として右側に所定距離シフトしている情報用記録マークＭＲ１と、トラック中心上に位置する情報用記録マークＭＣ１とが、グルーブトラックＧＴの進行方向に沿ってこの順に配列されている情報用マーク群ＭＧ１が、ビットデータ（ビット１）を構成する情報用マーク群ＭＧ１として、グルーブトラックＧＴに形成されてもよい。尚、図４（ｃ）は、情報用記録マークＭＣ１、情報用記録マークＭＬ１及び情報用記録マークＭＲ１の夫々の長さが、全て「ａ」となる例を示している。 As shown in FIG. 4C, the information recording mark MC1 located on the track center, the information recording mark ML1 shifted by a predetermined distance to the left with respect to the track center, and the right with respect to the track center. An information mark group MG1 in which an information recording mark MR1 shifted by a predetermined distance and an information recording mark MC1 located on the center of the track are arranged in this order along the traveling direction of the groove track GT is a bit. The information mark group MG1 constituting the data (bit 1) may be formed on the groove track GT. FIG. 4C shows an example in which the lengths of the information recording mark MC1, the information recording mark ML1, and the information recording mark MR1 are all “a”.
　この場合、図４（ｃ）に示す情報用マーク群ＭＧ１が形成されたグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、情報用記録マークＭＣ１、情報用記録マークＭＬ１、情報用記録マークＭＲ１及び情報用記録マークＭＣ１がこの順に読み取られることに起因して、「０」、「＋」、「－」及び「０」と変化する。従って、信号レベルが「０」、「＋」、「－」及び「０」の順に変化するプッシュプル信号から、ビットデータ（ビット１）が読み取られる。 In this case, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 tracing the groove track GT on which the information mark group MG1 shown in FIG. 4C is formed is the information recording mark MC1, Due to the fact that the information recording mark ML1, the information recording mark MR1, and the information recording mark MC1 are read in this order, it changes to “0”, “+”, “−”, and “0”. Therefore, bit data (bit 1) is read from a push-pull signal whose signal level changes in the order of “0”, “+”, “−”, and “0”.
　尚、図４に示す情報用マーク群ＭＧ１（つまり、同期データを構成する情報用マーク群ＭＧ１、並びにビットデータ（ビット０）を構成する情報用マーク群ＭＧ１及びビットデータ（ビット１）を構成する情報用マーク群ＭＧ１）の態様はあくまで一例である。従って、図４に示す態様以外の態様を示す３種類の情報用マーク群ＭＧ１を用いて、同期データ並びにビットデータ（ビット０）及びビットデータ（ビット１）が構成されてもよい。 Note that the information mark group MG1 shown in FIG. 4 (that is, the information mark group MG1 constituting the synchronization data, and the information mark group MG1 and bit data (bit 1) constituting the bit data (bit 0)) are constituted. The mode of the information mark group MG1) is merely an example. Therefore, the synchronization data, the bit data (bit 0), and the bit data (bit 1) may be configured by using the three types of information mark groups MG1 showing aspects other than those shown in FIG.
　（２－１－２）ランドトラックに形成される情報用マーク群の構成
　続いて、図５及び図６を参照して、ガイド層１２に形成される情報用マーク群ＭＧ１のうちランドトラックＬＴに形成される情報用マーク群ＭＧ１の構成について説明する。図５は、ランドトラックＬＴに形成される情報用マーク群ＭＧ１を構成する一対の情報用記録マークＭＬ１及びＭＲ１の構成を示す平面図である。図６は、ランドトラックＬＴに形成される情報用マーク群ＭＧ１によって多種類のデータ（具体的には、ビットデータ及び同期データ）が記録される態様を示す平面図である。 (2-1-2) Configuration of Information Mark Group Formed on Land Track Subsequently, with reference to FIGS. 5 and 6, the information mark group MG1 formed on the guide layer 12 includes a land track LT. The configuration of the formed information mark group MG1 will be described. FIG. 5 is a plan view showing a configuration of a pair of information recording marks ML1 and MR1 constituting the information mark group MG1 formed on the land track LT. FIG. 6 is a plan view showing an aspect in which various types of data (specifically, bit data and synchronization data) are recorded by the information mark group MG1 formed on the land track LT.
　図５に示すように、ランドトラックＬＴには、当該ランドトラックＬＴのトラック中心を基準として左右に等距離シフトした一対の情報用記録マークＭＬ１及びＭＲ１が形成されている。より具体的には、ランドトラックＬＴには、(i)ランドトラックＬＴのトラック中心を基準として左側（例えば、ランドトラックＬＴの進行方向に対して左側）のに所定距離だけシフトした情報用記録マークＭＬ１と、(ii)ランドトラックＬＴのトラック中心を基準として右側（例えば、ランドトラックＬＴの進行方向に対して右側）に所定距離だけシフトした情報用記録マークＭＲ１が形成されている。 As shown in FIG. 5, the land track LT is formed with a pair of information recording marks ML1 and MR1 that are shifted equidistant from side to side with respect to the track center of the land track LT. More specifically, the land track LT includes (i) an information recording mark shifted by a predetermined distance to the left side (for example, the left side with respect to the traveling direction of the land track LT) with respect to the track center of the land track LT. ML and (ii) an information recording mark MR1 shifted by a predetermined distance to the right side (for example, right side with respect to the traveling direction of the land track LT) with respect to the track center of the land track LT.
　ランドトラックＬＴに形成される情報用マーク群ＭＧ１は、このような一対の情報用記録マークＭＬ１及びＭＲ１から構成される。例えば、図５は、ランドトラックＬＴに形成される情報用マーク群ＭＧ１が、一対の情報用記録マークＭＬ１及びＭＲ１そのものである（つまり、ただ一つの一対の情報用記録マークＭＬ１及びＭＲ１が組み合わせられた）情報用マーク群ＭＧ１である例を示している。但し、後の図６等を参照して説明するように、ランドトラックＬＴに形成される情報用マーク群ＭＧ１は、一対の情報用記録マークＭＬ１及びＭＲ１が複数組み合わせられた情報用マーク群ＭＧ１であってもよいし、一又は複数の一対の情報用記録マークＭＬ１及びＭＲ１と一又は複数のその他の情報用記録マーク（例えば、記録マークの中心がトラック中心上に位置する他の情報用記録マークＭＣ１（図４（ａ）参照）若しくは情報用記録マークが形成されない領域（図６（ａ）参照））とが組み合わせられた情報用マーク群ＭＧ１であってもよい。 The information mark group MG1 formed on the land track LT is composed of such a pair of information recording marks ML1 and MR1. For example, in FIG. 5, the information mark group MG1 formed on the land track LT is a pair of information recording marks ML1 and MR1 itself (that is, only one pair of information recording marks ML1 and MR1 are combined. An example of the information mark group MG1 is shown. However, as described later with reference to FIG. 6 and the like, the information mark group MG1 formed on the land track LT is an information mark group MG1 in which a plurality of pairs of information recording marks ML1 and MR1 are combined. There may be one or more pairs of information recording marks ML1 and MR1 and one or more other information recording marks (for example, other information recording marks in which the center of the recording mark is located on the track center). The information mark group MG1 may be combined with MC1 (see FIG. 4A) or an area where the information recording mark is not formed (see FIG. 6A).
　本実施例では、同一の情報用マーク群ＭＧ１は、複数のランドトラックＬＴの夫々の同一の回転位相位置（言い換えれば、同一の回転角度位置）に形成される。つまり、同一の情報用マーク群ＭＧ１は、ランドトラックＬＴの進行方向（図５中の左側から右側に向かう方向）に対して直交する方向（つまり、図５の上下方向）に沿って相隣接する又は配列するように、複数のランドトラックＬＴの夫々に形成される。図５は、３つのランドトラックＬＴ（つまり、トラック番号が「ｋ－１」となるランドトラックＬＴ、トラック番号が「ｋ＋１」となるランドトラックＬＴ及びトラック番号が「ｋ＋３」となるランドトラックＬＴ）の夫々の同一の回転位相位置に、情報用記録マークＭＬ１と情報用記録マークＭＲ１とがランドトラックＬＴの進行方向に沿ってこの順に配列されている情報用マーク群ＭＧ１が形成される例を示している。 In the present embodiment, the same information mark group MG1 is formed at the same rotation phase position (in other words, the same rotation angle position) of each of the plurality of land tracks LT. That is, the same information mark group MG1 is adjacent to each other along a direction orthogonal to the traveling direction of the land track LT (the direction from the left side to the right side in FIG. 5) (that is, the vertical direction in FIG. 5). Alternatively, it is formed on each of the plurality of land tracks LT so as to be arranged. FIG. 5 shows three land tracks LT (ie, a land track LT with a track number “k−1”, a land track LT with a track number “k + 1”, and a land track LT with a track number “k + 3”). An information mark group MG1 in which the information recording mark ML1 and the information recording mark MR1 are arranged in this order along the traveling direction of the land track LT is formed at the same rotational phase position. ing.
　特に、同一の情報用マーク群ＭＧ１は、ガイドレーザ光ＬＢ１のビームスポット（つまり、ガイド層１２上でのビームスポット）に包含されることになる複数のランドトラックＬＴの夫々の同一回転位相位置に形成される。言い換えれば、同一の情報用マーク群ＭＧ１が同一回転位相位置に形成されることになる複数のランドトラックＬＴの数は、ガイドレーザ光ＬＢ１のビームスポットに包含されるランドトラックＬＴの数と同一になる。図５は、ガイドレーザ光ＬＢ１のビームスポットに包含されることになる複数のランドトラックＬＴの数が「３本」である例を示している。従って、図５は、３つのランドトラックＬＴの夫々の同一の回転位相位置に、同一の情報用マーク群ＭＧ１（つまり、情報用記録マークＭＬ１と情報用記録マークＭＲ１とがランドトラックＬＴの進行方向に沿ってこの順に配列されている情報用マーク群ＭＧ１）が形成される例を示している。 In particular, the same information mark group MG1 is at the same rotational phase position of each of the plurality of land tracks LT to be included in the beam spot of the guide laser beam LB1 (that is, the beam spot on the guide layer 12). It is formed. In other words, the number of the plurality of land tracks LT in which the same information mark group MG1 is formed at the same rotational phase position is the same as the number of land tracks LT included in the beam spot of the guide laser beam LB1. Become. FIG. 5 shows an example in which the number of the plurality of land tracks LT to be included in the beam spot of the guide laser beam LB1 is “3”. Therefore, FIG. 5 shows that the same information mark group MG1 (that is, the information recording mark ML1 and the information recording mark MR1 travel in the traveling direction of the land track LT at the same rotational phase position of each of the three land tracks LT. The information mark group MG1) arrayed in this order along is formed.
　尚、図５は、ランドトラックＬＴの進行方向に沿って、情報用記録マークＭＬ１と情報用記録マークＭＲ１とがこの順に配列されている情報用マーク群ＭＧ１の例を示している。しかしながら、ランドトラックＬＴの進行方向に沿って、情報用記録マークＭＲ１と情報用記録マークＭＬ１とがこの順に配列されている情報用マーク群ＭＧ１が用いられてもよい。 FIG. 5 shows an example of the information mark group MG1 in which the information recording mark ML1 and the information recording mark MR1 are arranged in this order along the traveling direction of the land track LT. However, the information mark group MG1 in which the information recording marks MR1 and the information recording marks ML1 are arranged in this order along the traveling direction of the land track LT may be used.
　本実施例では、このような情報用マーク群ＭＧ１を用いて、プリフォーマット情報（例えば、クロック情報やアドレス情報や記録開始タイミング情報等）がガイド層１２に（特に、ランドトラックＬＴに）記録される。より具体的には、本実施例では、同一の回転位相位置に形成される同一の情報用マーク群ＭＧ１を用いて、プリフォーマット情報の一部を構成するビットデータがガイド層１２に予め記録されている。従って、ガイド層１２の複数箇所に形成された複数の異なる情報用マーク群ＭＧ１から得られるビットデータを組み合わせる（言い換えれば、統合する）ことで、一つのプリフォーマット情報が得られる。更に、本実施例では、このような情報用マーク群ＭＧ１を用いて、プリフォーマット情報の少なくとも一部を構成するビットデータを読み取るときの同期をとるための同期データがガイド層１２に記録される。但し、プリフォーマット情報の少なくとも一部を構成するビットデータや同期データに限らず、情報用マーク群ＭＧ１を用いて、任意のデータがガイド層１２に記録されてもよい。 In this embodiment, preformat information (for example, clock information, address information, recording start timing information, etc.) is recorded on the guide layer 12 (particularly, on the land track LT) using such information mark group MG1. The More specifically, in this embodiment, bit data constituting a part of the preformat information is recorded in advance on the guide layer 12 using the same information mark group MG1 formed at the same rotational phase position. ing. Therefore, one preformat information can be obtained by combining (in other words, integrating) bit data obtained from a plurality of different information mark groups MG1 formed at a plurality of locations on the guide layer 12. Further, in the present embodiment, using such information mark group MG1, synchronization data for synchronization when reading bit data constituting at least part of the preformat information is recorded in the guide layer 12. . However, not only the bit data and the synchronization data constituting at least part of the preformat information, but arbitrary data may be recorded on the guide layer 12 using the information mark group MG1.
　具体的には、図６（ａ）に示すように、情報用記録マークが形成されない領域と、トラック中心を基準として左側に所定距離シフトしている情報用記録マークＭＬ１と、情報用記録マークが形成されない領域と、トラック中心を基準として右側に所定距離シフトしている情報用記録マークＭＲ１とが、ランドトラックＬＴの進行方向に沿ってこの順に配列されている情報用マーク群ＭＧ１が、同期データを構成する情報用マーク群ＭＧ１として、ランドトラックＬＴに形成されてもよい。尚、図６（ａ）は、情報用記録マークが形成されない領域、情報用記録マークＭＬ１及び情報用記録マークＭＲ１の夫々の長さが、全て「ａ」となる例を示している。 Specifically, as shown in FIG. 6A, an area where the information recording mark is not formed, an information recording mark ML1 shifted to the left by a predetermined distance from the track center, and an information recording mark An information mark group MG1 in which an area not formed and an information recording mark MR1 shifted to the right by a predetermined distance with respect to the track center as a reference is arranged in this order along the traveling direction of the land track LT. May be formed on the land track LT as the information mark group MG1 constituting the. FIG. 6A shows an example in which the lengths of the area where the information recording mark is not formed, the information recording mark ML1, and the information recording mark MR1 are all “a”.
　この場合、図６（ａ）に示す情報用マーク群ＭＧ１が形成されたランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、情報用記録マークが形成されていない領域、情報用記録マークＭＬ１、情報用記録マークが形成されていない領域及び情報用記録マークＭＲ１がこの順に読み取られることに起因して、「０」、「＋」、「０」及び「－」と変化する。従って、信号レベルが「０」、「＋」、「０」及び「－」の順に変化するプッシュプル信号から、同期データが読み取られる。 In this case, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 tracing the land track LT on which the information mark group MG1 shown in FIG. The unrecorded area, the information recording mark ML1, the area where the information recording mark MR1 is not formed, and the information recording mark MR1 are read in this order, so that “0”, “+”, “0” and It changes to “-”. Therefore, the synchronization data is read from the push-pull signal whose signal level changes in the order of “0”, “+”, “0”, and “−”.
　図６（ｂ）に示すように、情報用記録マークが形成されない領域と、トラック中心を基準として右側に所定距離シフトしている情報用記録マークＭＲ１と、トラック中心を基準として左側に所定距離シフトしている情報用記録マークＭＬ１と、情報用記録マークが形成されない領域とが、ランドトラックＬＴの進行方向に沿ってこの順に配列されている情報用マーク群ＭＧ１が、ビットデータ（ビット０）を構成する情報用マーク群ＭＧ１として、ランドトラックＬＴに形成されてもよい。尚、図６（ｂ）は、情報用記録マークＭＬ１及び情報用記録マークＭＲ１の夫々の長さが、全て「ａ」となる例を示している。 As shown in FIG. 6B, the area where the information recording mark is not formed, the information recording mark MR1 shifted by a predetermined distance to the right with respect to the track center, and the predetermined distance shifted to the left with respect to the track center. The information mark group MG1 in which the information recording mark ML1 and the area where the information recording mark is not formed are arranged in this order along the traveling direction of the land track LT is used for the bit data (bit 0). The information mark group MG1 to be configured may be formed on the land track LT. FIG. 6B shows an example in which the lengths of the information recording mark ML1 and the information recording mark MR1 are all “a”.
　この場合、図６（ｂ）に示す情報用マーク群ＭＧ１が形成されたランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、情報用記録マークが形成されない領域、情報用記録マークＭＲ１、情報用記録マークＭＬ１及び情報用記録マークが形成されない領域がこの順に読み取られることに起因して、「０」、「－」、「＋」及び「０」と変化する。従って、信号レベルが「０」、「－」、「＋」及び「０」の順に変化するプッシュプル信号から、ビットデータ（ビット０）が読み取られる。 In this case, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 tracing the land track LT on which the information mark group MG1 shown in FIG. The non-recorded area, the information recording mark MR1, the information recording mark ML1, and the area where the information recording mark is not formed are read in this order, so that "0", "-", "+", and "0" Change. Therefore, bit data (bit 0) is read from a push-pull signal whose signal level changes in the order of “0”, “−”, “+”, and “0”.
　図６（ｃ）に示すように、情報用記録マークが形成されない領域と、トラック中心を基準として左側に所定距離シフトしている情報用記録マークＭＬ１と、トラック中心を基準として右側に所定距離シフトしている情報用記録マークＭＲ１と、情報用記録マークが形成されない領域とが、ランドトラックＬＴの進行方向に沿ってこの順に配列されている情報用マーク群ＭＧ１が、ビットデータ（ビット１）を構成する情報用マーク群ＭＧ１として、ランドトラックＬＴに形成されてもよい。尚、図６（ｃ）は、情報用記録マークＭＬ１及び情報用記録マークＭＲ１の夫々の長さが、全て「ａ」となる例を示している。 As shown in FIG. 6C, the area where the information recording mark is not formed, the information recording mark ML1 shifted to the left by a predetermined distance from the track center, and the right shift by a predetermined distance from the track center. The information mark group MG1 in which the recording mark for information MR1 and the area where the recording mark for information is not formed are arranged in this order along the traveling direction of the land track LT is the bit data (bit 1). The information mark group MG1 to be configured may be formed on the land track LT. FIG. 6C shows an example in which the lengths of the information recording mark ML1 and the information recording mark MR1 are all “a”.
　この場合、図６（ｃ）に示す情報用マーク群ＭＧ１が形成されたランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、情報用記録マークが形成されない領域、情報用記録マークＭＬ１、情報用記録マークＭＲ１及び情報用記録マークが形成されない領域がこの順に読み取られることに起因して、「０」、「＋」、「－」及び「０」と変化する。従って、信号レベルが「０」、「＋」、「－」及び「０」の順に変化するプッシュプル信号から、ビット１を示すビットデータが読み取られる。 In this case, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 tracing the land track LT on which the information mark group MG1 shown in FIG. The areas that are not formed, the information recording mark ML1, the information recording mark MR1, and the area where the information recording mark is not formed are read in this order, so that "0", "+", "-", and "0" Change. Therefore, bit data indicating bit 1 is read from a push-pull signal whose signal level changes in the order of “0”, “+”, “−”, and “0”.
　尚、図６に示す情報用マーク群ＭＧ１（つまり、同期データを構成する情報用マーク群ＭＧ１、並びにビットデータ（ビット０）を構成する情報用マーク群ＭＧ１及びビットデータ（ビット１）を構成する情報用マーク群ＭＧ１）の態様はあくまで一例である。従って、図６に示す態様以外の態様を示す３種類の情報用マーク群ＭＧ１を用いて、同期データ並びにビットデータ（ビット０）及びビットデータ（ビット１）が構成されてもよい。 Note that the information mark group MG1 shown in FIG. 6 (that is, the information mark group MG1 constituting the synchronization data, and the information mark group MG1 and bit data (bit 1) constituting the bit data (bit 0)) are constituted. The mode of the information mark group MG1) is merely an example. Therefore, the synchronization data, the bit data (bit 0), and the bit data (bit 1) may be configured by using the three types of information mark groups MG1 showing aspects other than those shown in FIG.
　このようなランドグルーブＬＴに形成される情報用マーク群ＭＧ１は、光ディスク１１の製造時には、グルーブトラックＧＴの形成と同時に形成されることが好ましい。というのも、グルーブトラックＧＴ並びに情報用記録マークＭＲ１及びＭＬ１が凹部となるため、光ディスク１１の製造時には、グルーブトラックＧＴ及び情報用マーク群ＭＧ１に相当する位置に対してカッティングレーザ光を用いたカッティングが行われる。つまり、グルーブトラックＧＴに相当する位置並びに情報用記録マークＭＲ１に相当する位置及び情報用記録マークＭＬ１に相当する位置に対して、カッティングレーザ光が照射される。一方で、ランドトラックＬＴが凸部となるため、光ディスク１１の製造時には、ランドトラックＬＴに相当する位置に対してカッティングレーザ光を用いたカッティングが行われなくともよい。つまり、ランドトラックＬＴに相当する位置に対して、カッティングレーザ光が照射されなくともよい。このため、ランドグルーブＬＴ上に形成される情報用マーク群ＭＧ１をグルーブトラックＧＴの形成と同時に形成すれば、ランドトラックＬＴの形成時にカッティングレーザ光を全く照射しなくともよくなる（言い換えれば、グルーブトラックＧＴの形成時にカッティングレーザ光のオンオフを切り替えればよくなる）。従って、光ディスク１１の製造工程の簡略化が図られる。 The information mark group MG1 formed on the land groove LT is preferably formed simultaneously with the formation of the groove track GT when the optical disc 11 is manufactured. This is because the groove track GT and the information recording marks MR1 and ML1 become concave portions, and therefore, when the optical disc 11 is manufactured, a cutting laser beam is used to cut the position corresponding to the groove track GT and the information mark group MG1. Is done. That is, the cutting laser light is irradiated to the position corresponding to the groove track GT, the position corresponding to the information recording mark MR1, and the position corresponding to the information recording mark ML1. On the other hand, since the land track LT is a convex portion, when the optical disc 11 is manufactured, the cutting laser light may not be cut at a position corresponding to the land track LT. That is, the cutting laser light does not have to be irradiated to the position corresponding to the land track LT. Therefore, if the information mark group MG1 formed on the land groove LT is formed simultaneously with the formation of the groove track GT, it is not necessary to irradiate the cutting laser beam at the time of forming the land track LT (in other words, the groove track). It is only necessary to switch the cutting laser light on and off when forming the GT). Therefore, the manufacturing process of the optical disk 11 can be simplified.
　（２－２）判別用マーク群の構成
　続いて、図７から図１２を参照して、ガイド層１２に形成される判別用マーク群ＭＧ２について説明する。 (2-2) Configuration of Discriminating Mark Group Next, the discriminating mark group MG2 formed on the guide layer 12 will be described with reference to FIGS.
　（２－２－１）グルーブトラックに形成される情報用マーク群のための判別用マーク群の構成
　はじめに、図７から図９を参照して、判別用マーク群ＭＧ２のうちグルーブトラックＧＴに形成される情報用マーク群ＭＧ１のための（つまり、グルーブトラックＧＴに形成される情報用マーク群ＭＧ１のセンタートラックを判別するための）判別用マーク群ＭＧ２の構成について説明する。図７は、グルーブトラックＧＴに形成される情報用マーク群ＭＧ１のための判別用マーク群ＭＧ２の構成を示す平面図である。図８は、判別用マーク群ＭＧ２が形成されたグルーブトラックＧＴ上をトレースするガイドレーザ光ＬＢ１の戻り光から得られるプッシュプル信号の信号レベルを示すグラフである。図９は、図７に示す判別用マーク群ＭＧ２を用いてセンタートラックＣＴを判別する動作を示すフローチャートである。 (2-2-1) Configuration of Discriminating Mark Group for Information Mark Group Formed on Groove Track First, with reference to FIGS. 7 to 9, the discriminating mark group MG2 is formed on the groove track GT. The configuration of the determination mark group MG2 for the information mark group MG1 to be performed (that is, for determining the center track of the information mark group MG1 formed on the groove track GT) will be described. FIG. 7 is a plan view showing the configuration of the discrimination mark group MG2 for the information mark group MG1 formed on the groove track GT. FIG. 8 is a graph showing the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 that traces on the groove track GT on which the discrimination mark group MG2 is formed. FIG. 9 is a flowchart showing an operation of discriminating the center track CT using the discrimination mark group MG2 shown in FIG.
　尚、図７から図９は、トラック番号が「ｋ－２」となるグルーブトラックＧＴ、トラック番号が「ｋ」となるグルーブトラックＧＴ及びトラック番号が「ｋ＋２」となるグルーブトラックＧＴの夫々の同一の回転位相位置に形成される同一の情報用マーク群ＭＧ１（図３参照）を対象として、トラック番号が「ｋ」となるグルーブトラックＧＴ（つまり、センタートラックＣＴ）を判別するための判別用マーク群ＭＧ２の構成の例を示している。 7 to 9, the groove track GT with the track number “k-2”, the groove track GT with the track number “k”, and the groove track GT with the track number “k + 2” are the same. A discrimination mark for discriminating a groove track GT (that is, a center track CT) having a track number “k” for the same information mark group MG1 (see FIG. 3) formed at the rotational phase position of The example of composition of group MG2 is shown.
　図７に示すように、判別用マーク群ＭＧ２は、センタートラックＣＴのトラック中心を基準として左右に等距離シフトした一対の判別用記録マークＭＬ２及びＭＲ２を含んでいる。具体的には、判別用マーク群ＭＧ２は、(i)センタートラックＣＴのトラック中心を基準として左側（例えば、センタートラックＣＴの進行方向に対して左側）に所定距離だけシフトした判別用記録マークＭＬ２と、(ii)センタートラックＣＴのトラック中心を基準として右側（例えば、センタートラックＣＴの進行方向に対して右側）に所定距離だけシフトした判別用記録マークＭＲ２とを含んでいる。 As shown in FIG. 7, the discrimination mark group MG2 includes a pair of discrimination recording marks ML2 and MR2 that are shifted equidistant from side to side with respect to the track center of the center track CT. Specifically, the discrimination mark group MG2 includes (i) a discrimination recording mark ML2 shifted by a predetermined distance to the left side (for example, the left side with respect to the traveling direction of the center track CT) with respect to the track center of the center track CT. And (ii) a discriminating recording mark MR2 shifted by a predetermined distance to the right side (for example, right side with respect to the traveling direction of the center track CT) with respect to the track center of the center track CT.
　一対の判別用記録マークＭＬ２及びＭＲ２は、同一の回転位相位置に形成されていてもよい。図７は、一対の判別用記録マークＭＬ２（＃２）及びＭＲ２（＃２）が同一の回転位相位置に形成される例を示している。或いは、一対の判別用記録マークＭＬ２及びＭＲ２は、異なる回転位相位置に形成されていてもよい。図７は、一対の判別用記録マークＭＬ２（＃１）及びＭＲ２（＃１）が異なる回転位相位置に形成される例を示している。 The pair of discrimination recording marks ML2 and MR2 may be formed at the same rotational phase position. FIG. 7 shows an example in which the pair of discrimination recording marks ML2 (# 2) and MR2 (# 2) are formed at the same rotational phase position. Alternatively, the pair of determination recording marks ML2 and MR2 may be formed at different rotational phase positions. FIG. 7 shows an example in which the pair of discrimination recording marks ML2 (# 1) and MR2 (# 1) are formed at different rotational phase positions.
　判別用マーク群ＭＧ２は、このような一対の判別用記録マークＭＬ２及びＭＲ２から構成される。例えば、図７は、グルーブトラックＧＴに形成される判別用マーク群ＭＧ２が、同一の回転位相位置に形成される一対の判別用記録マークＭＬ２（＃２）及びＭＲ２（＃２）並びに異なる回転位相位置に形成される一対の判別用記録マークＭＬ２（＃１）及びＭＲ２（＃１）を含む判別用マーク群ＭＧ２である例を示している。但し、グルーブトラックＧＴに形成される判別用マーク群ＭＧ２は、一対の判別用記録マークＭＬ２及びＭＲ２をただ一つだけ含んでいてもよいし、一又は複数の一対の判別用記録マークＭＬ２及びＭＲ２と一又は複数のその他の記録マーク（例えば、判別用記録マークの中心がセンタートラックＣＴのトラック中心上に位置する他の判別用記録マーク）若しくは判別用記録マークが形成されない領域とが組み合わせられた判別用マーク群ＭＧ２であってもよい。 The discrimination mark group MG2 includes such a pair of discrimination recording marks ML2 and MR2. For example, FIG. 7 shows that the discrimination mark group MG2 formed on the groove track GT has a pair of discrimination recording marks ML2 (# 2) and MR2 (# 2) formed at the same rotational phase position and different rotational phases. An example is shown in which the discrimination mark group MG2 includes a pair of discrimination recording marks ML2 (# 1) and MR2 (# 1) formed at positions. However, the discrimination mark group MG2 formed on the groove track GT may include only one pair of discrimination recording marks ML2 and MR2, or one or more pairs of discrimination recording marks ML2 and MR2. And one or a plurality of other recording marks (for example, other discrimination recording marks whose center of the discrimination recording mark is located on the track center of the center track CT) or an area where no discrimination recording mark is formed. The determination mark group MG2 may be used.
　本実施例では、判別用マーク群ＭＧ２を構成する判別用記録マークＭＬ２及び判別用記録マークＭＲ２の夫々の幅（つまり、グルーブトラックＧＴの進行方向に対して直交する方向（つまり、光ディスク１０の半径方向）に沿った長さであって、図７の上下方向の長さ）は、ガイドトラックＴＲの幅（或いは、グルーブトラックＧＴの幅）の２倍以上である。図７は、判別用記録マークＭＬ２及び判別用記録マークＭＲ２の夫々の幅が、ガイドトラックＴＲの幅の２倍となる例を示している。但し、判別用記録マークＭＬ２及び判別用記録マークＭＲ２の夫々の幅は、ガイドトラックＴＲの幅の２倍未満であり且つガイドトラックＴＲの幅よりも大きくともよい。 In this embodiment, the width of each of the determination recording mark ML2 and the determination recording mark MR2 constituting the determination mark group MG2 (that is, the direction orthogonal to the traveling direction of the groove track GT (that is, the radius of the optical disk 10). (Length in the vertical direction in FIG. 7) is at least twice the width of the guide track TR (or the width of the groove track GT). FIG. 7 shows an example in which the width of each of the determination recording mark ML2 and the determination recording mark MR2 is twice the width of the guide track TR. However, the width of each of the determination recording mark ML2 and the determination recording mark MR2 may be less than twice the width of the guide track TR and larger than the width of the guide track TR.
　尚、図７は、グルーブトラックＧＴの進行方向に沿って、判別用記録マークＭＬ２と判別用記録マークＭＲ２とがこの順に配列されている判別用マーク群ＭＧ１の例を示している。しかしながら、グルーブトラックＧＴの進行方向に沿って、判別用記録マークＭＲ２と判別用記録マークＭＬ２とがこの順に配列されている判別用マーク群ＭＧ２が用いられてもよい。 FIG. 7 shows an example of the discrimination mark group MG1 in which the discrimination recording mark ML2 and the discrimination recording mark MR2 are arranged in this order along the traveling direction of the groove track GT. However, a discrimination mark group MG2 in which discrimination recording marks MR2 and discrimination recording marks ML2 are arranged in this order along the traveling direction of the groove track GT may be used.
　また、図７は、グルーブトラックＧＴが凹部となり且つランドトラックＬＴが凸部となると共に、判別用記録マークＭＬ２及びＭＲ２が凹部となる例を示している。但し、グルーブトラックＧＴが凸部となり且つランドトラックＬＴが凹部となると共に、判別用記録マークＭＬ２及びＭＲ２が凸部となっていてもよい。 FIG. 7 shows an example in which the groove track GT becomes a concave portion and the land track LT becomes a convex portion, and the determination recording marks ML2 and MR2 become concave portions. However, the groove track GT may be a convex portion and the land track LT may be a concave portion, and the determination recording marks ML2 and MR2 may be convex portions.
　本実施例では、このような判別用マーク群ＭＧ２を用いて、同一の情報用マーク群ＭＧ１が形成されている複数のグルーブトラックＧＴのうちのセンタートラックＣＴが判別される。センタートラックＣＴが判別された後には、センタートラックＣＴをトレースする（つまり、センタートラックＣＴ上にスポット中心が位置する）ガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号に基づいて、情報用マーク群ＭＧ１が示すプリフォーマット情報が読み取られる。 In this embodiment, such a determination mark group MG2 is used to determine the center track CT among a plurality of groove tracks GT on which the same information mark group MG1 is formed. After the center track CT is determined, the center track CT is traced (that is, the center of the spot is located on the center track CT), based on the push-pull signal generated from the return light of the guide laser beam LB1. The preformat information indicated by the mark group MG1 is read.
　センタートラックＣＴが判別される際には、判別用マーク群ＭＧ２が形成されているグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から得られるプッシュプル信号の信号レベルと所定の第１閾値ａ（但し、ａは、正の実数）及び所定の第２閾値ｂ（但し、ｂは、ａよりも小さい正の実数）との比較が行われる。このようなプッシュプル信号の信号レベルと第１閾値ａ及び第２閾値ｂとの比較は、判別用記録マークＭＬ２及びＭＲ２が形成される単位（図７では、“マーク区間”と表現）毎に行われる。 When the center track CT is discriminated, the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 tracing the groove track GT on which the discriminating mark group MG2 is formed, and a predetermined first threshold value a A comparison is made with (where a is a positive real number) and a predetermined second threshold value b (where b is a positive real number smaller than a). The comparison between the signal level of the push-pull signal and the first threshold value a and the second threshold value b is made for each unit (expressed as “mark section” in FIG. 7) in which the recording marks ML2 and MR2 for determination are formed. Done.
　具体的には、まず、プッシュプル信号の信号レベルと第１閾値ａ及び第２閾値ｂとの比較結果に応じて、各マーク区間がどのような区間であるかが判定される。図８に示すように、プッシュプル信号の信号レベルが＋ａより大きくなる（つまり、＋ａ＜信号レベルとなる）場合には、当該マーク区間は「＋区間」であると判定される。また、プッシュプル信号の信号レベルが－ａより小さくなる（つまり、信号レベル＜－ａとなる）場合には、当該マーク区間は「－区間」であると判定される。また、プッシュプル信号の信号レベルがａ以下であって且つｂより大きい（つまり、ｂ＜信号レベル≦ａとなる）場合には、当該マーク区間は「＋不定区間」であると判定される。また、プッシュプル信号の信号レベルが－ａ以上であって且つ－ｂ未満となる（つまり、－ａ≦信号レベル＜－ｂとなる）場合には、当該マーク区間は「－不定区間」であると判定される。また、プッシュプル信号の信号レベルが－ｂ以上であって且つｂ未満となる（つまり、－ｂ≦信号レベル≦ｂとなる）場合には、当該マーク区間は「０区間」であると判定される。 Specifically, first, according to the comparison result between the signal level of the push-pull signal and the first threshold value a and the second threshold value b, it is determined what section each mark section is. As shown in FIG. 8, when the signal level of the push-pull signal is higher than + a (that is, + a <signal level), it is determined that the mark section is “+ section”. When the signal level of the push-pull signal is smaller than −a (that is, when the signal level <−a), the mark section is determined to be “−section”. Further, when the signal level of the push-pull signal is a or less and greater than b (that is, b <signal level ≦ a), it is determined that the mark section is “+ indefinite section”. In addition, when the signal level of the push-pull signal is equal to or higher than −a and lower than −b (that is, −a ≦ signal level <−b), the mark interval is “−indefinite interval”. It is determined. Further, when the signal level of the push-pull signal is −b or more and less than b (that is, −b ≦ signal level ≦ b), the mark section is determined to be “0 section”. The
　より具体的には、図８の１番目のグラフは、トラック番号が「ｋ－２」となるグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルを示している。この信号レベルは、第１マーク区間が「＋区間」であり、第２マーク区間が「－区間」であり且つ第３マーク区間が「０区間」であることを示している。 More specifically, the first graph in FIG. 8 shows the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT whose track number is “k-2”. ing. This signal level indicates that the first mark section is “+ section”, the second mark section is “− section”, and the third mark section is “0 section”.
　同様に、図８の２番目のグラフは、トラック番号が「ｋ」となるグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルを示している。この信号レベルは、第１マーク区間が「－区間」であり、第２マーク区間が「＋不定区間及び－不定区間」であり且つ第３マーク区間が「＋区間」であることを示している。 Similarly, the second graph of FIG. 8 shows the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k”. This signal level indicates that the first mark section is “−section”, the second mark section is “+ undefined section and −undefined section”, and the third mark section is “+ section”. .
　尚、第２マーク区間では、本来は、「０区間」と判定されることが好ましい。しかしながら、実際の記録再生装置においては、ガイドレーザ光ＬＢ１のトラッキングずれやガイドレーザ光ＬＢ１の戻り光を受光するフォトディテクタの取り付け位置のずれ等に起因して、図８に示すように、ｂよりも大きい信号レベルや－ｂよりも小さい信号レベルが検出されることがある。或いは、実際の記録再生装置においては、ガイドレーザ光ＬＢ１のトラッキングずれやガイドレーザ光ＬＢ１の戻り光を受光するフォトディテクタの取り付け位置のずれ等に起因して、ａよりも大きい信号レベルや－ａよりも小さい信号レベルが検出されることがある。しかしながら、第２マーク区間において仮にｂ若しくはａよりも大きい信号レベルや－ｂ若しくは－ａよりも小さい信号レベルが検出される場合には、ｂ若しくはａよりも大きい信号レベル及び－ｂ若しくは－ａよりも小さい信号レベルの双方が検出されるはずである。従って、単一のマーク区間内においてｂ若しくはａよりも大きい信号レベル及び－ｂ若しくは－ａよりも小さい信号レベルの双方が検出された場合には、当該マーク区間は、「隣接ではない区間（つまり、センタートラックＣＴである可能性が相対的に高い区間）」であると判定されることが好ましい。 In the second mark section, it is preferably determined that it is originally “0 section”. However, in the actual recording / reproducing apparatus, as shown in FIG. 8, the tracking laser beam is shifted more than b as shown in FIG. 8 due to the tracking shift of the guide laser beam LB1 or the shift of the mounting position of the photodetector that receives the return light of the guide laser beam LB1. A large signal level or a signal level smaller than −b may be detected. Alternatively, in an actual recording / reproducing apparatus, a signal level higher than a or -a due to a tracking shift of the guide laser beam LB1 or a shift of a mounting position of a photodetector that receives the return light of the guide laser beam LB1. A small signal level may be detected. However, if a signal level higher than b or a or a signal level lower than -b or -a is detected in the second mark section, a signal level higher than b or a and -b or -a. Both small signal levels should be detected. Therefore, when both a signal level higher than b or a and a signal level lower than −b or −a are detected in a single mark interval, the mark interval is “a non-adjacent interval (that is, It is preferable to determine that the section is relatively likely to be the center track CT).
　同様に、図８の３番目のグラフは、トラック番号が「ｋ＋２」となるグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルを示している。この信号レベルは、第１マーク区間が「０区間」であり、第２マーク区間が「＋区間」であり且つ第３マーク区間が「－区間」であることを示している。 Similarly, the third graph in FIG. 8 shows the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT whose track number is “k + 2”. This signal level indicates that the first mark section is “0 section”, the second mark section is “+ section”, and the third mark section is “−section”.
　その後、各マーク区間の判定結果の組み合わせに応じて、ガイドレーザ光ＬＢ１がトレースしているグルーブトラックＧＴがセンタートラックＣＴであるか否かが判別される。 Thereafter, whether or not the groove track GT traced by the guide laser beam LB1 is the center track CT is determined according to the combination of the determination results of the respective mark sections.
　具体的には、図９に示すように、まず、第１マーク区間が「－区間」であるか否かが判定される（ステップＳ１１）。 Specifically, as shown in FIG. 9, it is first determined whether or not the first mark section is “−section” (step S11).
　ステップＳ１１の判定の結果、第１マーク区間が「－区間」であると判定される場合には（ステップＳ１１：Ｙｅｓ）、続いて、第３マーク区間が「＋区間」であるか否かが判定される（ステップＳ１２）。 As a result of the determination in step S11, if it is determined that the first mark section is “−section” (step S11: Yes), then whether or not the third mark section is “+ section” is determined. Determination is made (step S12).
　ステップＳ１２の判定の結果、第３マーク区間が「＋区間」であると判定される場合には（ステップＳ１２：Ｙｅｓ）、ガイドレーザ光ＬＢ１が現在トレースしているグルーブトラックＧＴがセンタートラックＣＴであると判別される（ステップＳ１３）。 As a result of the determination in step S12, when it is determined that the third mark section is “+ section” (step S12: Yes), the groove track GT currently being traced by the guide laser beam LB1 is the center track CT. It is determined that there is (step S13).
　他方で、ステップＳ１２の判定の結果、第３マーク区間が「＋区間」でないと判定される場合には（ステップＳ１２：Ｎｏ）、続いて、第３マーク区間が「＋不定区間」であるか否かが判定される（ステップＳ１６）。 On the other hand, as a result of the determination in step S12, if it is determined that the third mark section is not the “+ section” (step S12: No), then, is the third mark section a “+ indefinite section”? It is determined whether or not (step S16).
　ステップＳ１６の判定の結果、第３マーク区間が「＋不定区間」であると判定される場合には（ステップＳ１６：Ｙｅｓ）、ガイドレーザ光ＬＢ１が現在トレースしているグルーブトラックＧＴがセンタートラックＣＴであると判別される（ステップＳ１３）。 As a result of the determination in step S16, if it is determined that the third mark section is “+ undefined section” (step S16: Yes), the groove track GT currently being traced by the guide laser beam LB1 is the center track CT. (Step S13).
　他方で、ステップＳ１６の判定の結果、第３マーク区間が「＋不定区間」でないと判定される場合には（ステップＳ１６：Ｎｏ）、ガイドレーザ光ＬＢ１がトレースしているグルーブトラックＧＴがセンタートラックＣＴでないと判別される（ステップＳ１７）。 On the other hand, if it is determined in step S16 that the third mark section is not “+ undefined section” (step S16: No), the groove track GT traced by the guide laser beam LB1 is the center track. It is determined that it is not CT (step S17).
　他方で、ステップＳ１１の判定の結果、第１マーク区間が「－区間」でないと判定される場合には（ステップＳ１１：Ｎｏ）、続いて、第１マーク区間が「－不定区間」であるか否かが判定される（ステップＳ１４）。 On the other hand, if it is determined in step S11 that the first mark section is not “−section” (step S11: No), then whether the first mark section is “−undefined section” or not. It is determined whether or not (step S14).
　ステップＳ１４の判定の結果、第１マーク区間が「－不定区間」であると判定される場合には（ステップＳ１４：Ｙｅｓ）、続いて、第２マーク区間が「隣接ではない区間」であるか否かが判定される（ステップＳ１５）。 As a result of the determination in step S14, if it is determined that the first mark section is “−indefinite section” (step S14: Yes), then whether the second mark section is “a section that is not adjacent”. It is determined whether or not (step S15).
　ステップＳ１５の判定の結果、第２マーク区間が「隣接ではない区間」であると判定される場合には（ステップＳ１５：Ｙｅｓ）、ステップＳ１２以降の動作が行われる。 As a result of the determination in step S15, when it is determined that the second mark section is “a section that is not adjacent” (step S15: Yes), the operations after step S12 are performed.
　他方で、ステップＳ１５の判定の結果、第２マーク区間が「隣接ではない区間」でないと判定される場合には（ステップＳ１５：Ｎｏ）、ガイドレーザ光ＬＢ１が現在トレースしているグルーブトラックＧＴがセンタートラックＣＴでないと判別される（ステップＳ１７）。 On the other hand, as a result of the determination in step S15, when it is determined that the second mark section is not “a non-adjacent section” (step S15: No), the groove track GT currently being traced by the guide laser beam LB1 is determined. It is determined that the track is not the center track CT (step S17).
　他方で、ステップＳ１４の判定の結果、第１マーク区間が「－不定区間」でないと判定される場合には（ステップＳ１４：Ｎｏ）、ガイドレーザ光ＬＢ１が現在トレースしているグルーブトラックＧＴがセンタートラックＣＴでないと判別される（ステップＳ１７）。 On the other hand, as a result of the determination in step S14, when it is determined that the first mark section is not “−undefined section” (step S14: No), the groove track GT currently being traced by the guide laser beam LB1 is the center track. It is determined that it is not the track CT (step S17).
　図９に示す動作を図８に示す判別用マーク群ＭＧ２に具体的に適用した場合の例について、以下に説明する。 An example in which the operation shown in FIG. 9 is specifically applied to the discrimination mark group MG2 shown in FIG. 8 will be described below.
　トラック番号が「ｋ－２」となるグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「＋区間」であり、第２マーク区間が「－区間」であり且つ第３マーク区間が「０区間」であることを示している。従って、この場合には、第１マーク区間が－区間でない（ステップＳ１１：Ｎｏ）と判定され且つ第１マーク区間が－不定区間でない（ステップＳ１４：Ｎｏ）と判定される。従って、ガイドレーザ光ＬＢ１が現在トレースしているグルーブトラックＧＴ（つまり、トラック番号が「ｋ－２」となるグルーブトラックＧＴ）がセンタートラックＣＴでないと判別される（ステップＳ１７）。 The signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k−2” is the “+ section” in the first mark section, and the second mark This indicates that the section is “−section” and the third mark section is “0 section”. Therefore, in this case, it is determined that the first mark section is not a −section (step S11: No), and the first mark section is not a −indefinite section (step S14: No). Accordingly, it is determined that the groove track GT currently traced by the guide laser beam LB1 (that is, the groove track GT with the track number “k−2”) is not the center track CT (step S17).
　続いて、トラック番号が「ｋ」となるグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「－区間」であり、第２マーク区間が「隣接ではない区間」であり且つ第３マーク区間が「＋区間」であることを示している。従って、この場合には、第１マーク区間が－区間である（ステップＳ１１：Ｙｅｓ）と判定され且つ第３マーク区間が＋区間である（ステップＳ１２：Ｙｅｓ）と判定される。従って、ガイドレーザ光ＬＢ１が現在トレースしているグルーブトラックＧＴ（つまり、トラック番号が「ｋ」となるグルーブトラックＧＴ）がセンタートラックＣＴであると判別される（ステップＳ１３）。 Subsequently, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k” is the “−section” in the first mark section, The mark section is “a section that is not adjacent”, and the third mark section is “+ section”. Therefore, in this case, it is determined that the first mark section is the-section (step S11: Yes) and the third mark section is the + section (step S12: Yes). Therefore, it is determined that the groove track GT currently traced by the guide laser beam LB1 (that is, the groove track GT with the track number “k”) is the center track CT (step S13).
　同様に、トラック番号が「ｋ＋２」となるグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「０区間」であり、第２マーク区間が「＋区間」であり且つ第３マーク区間が「－区間」であることを示している。従って、この場合には、第１マーク区間が－区間でない（ステップＳ１１：Ｎｏ）と判定され且つ第１マーク区間が－不定区間でない（ステップＳ１４：Ｎｏ）と判定される。従って、ガイドレーザ光ＬＢ１が現在トレースしているグルーブトラックＧＴ（つまり、トラック番号が「ｋ＋２」となるグルーブトラックＧＴ）がセンタートラックＣＴでないと判別される（ステップＳ１７）。 Similarly, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k + 2” is “0 section” in the first mark section, The mark section is “+ section” and the third mark section is “− section”. Therefore, in this case, it is determined that the first mark section is not a −section (step S11: No), and the first mark section is not a −indefinite section (step S14: No). Therefore, it is determined that the groove track GT currently traced by the guide laser beam LB1 (that is, the groove track GT with the track number “k + 2”) is not the center track CT (step S17).
　このように、判別用マーク群ＭＧ２を用いて、センタートラックＣＴが好適に判別される。 Thus, the center track CT is suitably discriminated using the discrimination mark group MG2.
　尚、図７及び図８に示す判別用マーク群ＭＧ２の態様はあくまで一例である。従って、図７及び図８に示す態様以外の態様を示す判別用マーク群ＭＧ２（つまり、同一の回転位相位置に形成される一対の判別用記録マークＭＬ２及びＭＲ２並びに異なる回転位相位置に形成される一対の判別用記録マークＭＬ２及びＭＲ２の少なくとも一方を一つ以上含む任意の判別用マーク群ＭＧ２）を用いて、センタートラックＣＴが判別されてもよい。この場合、当然に、図９に示すフローチャートも、図７及び図８に示す態様以外の態様を示す判別用マーク群ＭＧ２に合わせて変更されることが好ましい。 Note that the mode of the discrimination mark group MG2 shown in FIGS. 7 and 8 is merely an example. Accordingly, a discrimination mark group MG2 showing a mode other than the mode shown in FIGS. 7 and 8 (that is, a pair of discrimination recording marks ML2 and MR2 formed at the same rotational phase position and different rotational phase positions). The center track CT may be discriminated using an arbitrary discriminating mark group MG2) including at least one of the pair of discriminating recording marks ML2 and MR2. Naturally, in this case, it is preferable that the flowchart shown in FIG. 9 is also changed in accordance with the determination mark group MG2 showing a mode other than the modes shown in FIGS.
　また、図７は、判別用記録マークＭＬ２（＃１）と一対の判別用記録マークＭＬ２（＃２）及びＭＲ２（＃２）と判別用記録マークＭＲ２（＃１）とが連続的に（言い換えれば、間隔をあけずに）形成される例を示している。しかしながら、判別用記録マークＭＬ２（＃１）と一対の判別用記録マークＭＬ２（＃２）及びＭＲ２（＃２）と判別用記録マークＭＲ２（＃１）とが離散的に（言い換えれば、間隔をあけて）形成されてもよい。 FIG. 7 shows that the determination recording mark ML2 (# 1), the pair of determination recording marks ML2 (# 2) and MR2 (# 2), and the determination recording mark MR2 (# 1) are continuously (in other words, In this example, the gap is formed without a gap. However, the discriminating recording mark ML2 (# 1), the pair of discriminating recording marks ML2 (# 2) and MR2 (# 2), and the discriminating recording mark MR2 (# 1) are discretely (in other words, spaced apart). May be formed).
　（２－２－２）ランドトラックに形成される判別用マーク群の構成
　続いて、図１０から図１２を参照して、判別用マーク群ＭＧ２のうちランドトラックＬＴに形成される情報用マーク群ＭＧ１のための（つまり、ランドトラックＬＴに形成される情報用マーク群ＭＧ１のセンタートラックを判別するための）判別用マーク群ＭＧ２の構成について説明する。図１０は、ランドトラックＬＴに形成される情報用マーク群ＭＧ１のための判別用マーク群ＭＧ２の構成を示す平面図である。図１１は、判別用マーク群ＭＧ２が形成されたランドトラックＬＴ上をトレースするガイドレーザ光ＬＢ１の戻り光から得られるプッシュプル信号の信号レベルを示すグラフである。図１２は、図１０に示す判別用マーク群ＭＧ２を用いてセンタートラックＣＴを判別する動作を示すフローチャートである。 (2-2-2) Configuration of Discrimination Mark Group Formed on Land Track Subsequently, with reference to FIGS. 10 to 12, an information mark group formed on the land track LT in the discrimination mark group MG2 The configuration of the determination mark group MG2 for MG1 (that is, for determining the center track of the information mark group MG1 formed on the land track LT) will be described. FIG. 10 is a plan view showing the configuration of the discrimination mark group MG2 for the information mark group MG1 formed on the land track LT. FIG. 11 is a graph showing the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 that traces on the land track LT on which the discrimination mark group MG2 is formed. FIG. 12 is a flowchart showing an operation of discriminating the center track CT using the discrimination mark group MG2 shown in FIG.
　尚、図１０から図１２は、トラック番号が「ｋ－１」となるランドトラックＬＴ、トラック番号が「ｋ＋１」となるランドトラックＬＴ及びトラック番号が「ｋ＋３」となるランドトラックＬＴの夫々の同一の回転位相位置に形成される同一の情報用マーク群ＭＧ１（図５参照）を対象として、トラック番号が「ｋ＋１」となるランドトラックＬＴ（つまり、センタートラックＣＴ）を判別するための判別用マーク群ＭＧ２の構成の例を示している。 10 to 12, the land track LT with the track number “k−1”, the land track LT with the track number “k + 1”, and the land track LT with the track number “k + 3” are the same. A discriminating mark for discriminating the land track LT (that is, the center track CT) whose track number is “k + 1” for the same information mark group MG1 (see FIG. 5) formed at the rotational phase position of The example of composition of group MG2 is shown.
　図１０に示すように、ランドトラックＬＴに形成される判別用マーク群ＭＧ２は、グルーブトラックＧＴに形成される判別用マーク群ＭＧ２と同様に、センタートラックＣＴのトラック中心を基準として左右に等距離シフトした一対の判別用記録マークＭＬ２及びＭＲ２を含んでいる。従って、ランドトラックＬＴに形成される判別用マーク群ＭＧ２の特徴のうちグルーブトラックＧＴに形成される判別用マーク群ＭＧ２と同様の特徴については、詳細な説明を省略する。 As shown in FIG. 10, the discrimination mark group MG2 formed on the land track LT is equidistant from side to side with respect to the track center of the center track CT, like the discrimination mark group MG2 formed on the groove track GT. It includes a pair of shifted recording marks ML2 and MR2. Accordingly, the detailed description of the features of the discrimination mark group MG2 formed on the land track LT that are the same as those of the discrimination mark group MG2 formed on the groove track GT will be omitted.
　本実施例では、このような判別用マーク群ＭＧ２を用いて、同一の情報用マーク群ＭＧ１が形成されている複数のランドトラックＬＴのうちのセンタートラックＣＴが判別される。センタートラックＣＴが判別された後には、センタートラックＣＴをトレースする（つまり、センタートラックＣＴ上にスポット中心が位置する）ガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号に基づいて、情報用マーク群ＭＧ１が示すプリフォーマット情報が読み取られる。 In this embodiment, such a determination mark group MG2 is used to determine the center track CT among a plurality of land tracks LT on which the same information mark group MG1 is formed. After the center track CT is determined, the center track CT is traced (that is, the center of the spot is located on the center track CT), based on the push-pull signal generated from the return light of the guide laser beam LB1. The preformat information indicated by the mark group MG1 is read.
　センタートラックＣＴが判別される際には、判別用マーク群ＭＧが形成されているランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から得られるプッシュプル信号の信号レベルと所定の第１閾値ａ及び所定の第２閾値ｂとの比較が行われる。このようなプッシュプル信号の信号レベルと第１閾値ａ及び第２閾値ｂとの比較は、判別用記録マークＭＬ２及びＭＲ２が形成される単位（つまり、マーク区間）毎に行われる。つまり、ランドトラックＬＴに形成される判別用マーク群ＭＧ２についても、グルーブトラックＧＴに形成される判別用マーク群ＭＧ２と同様に、各マーク区間がどのような区間であるかが判定される。 When the center track CT is discriminated, the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 tracing the land track LT on which the discrimination mark group MG is formed and a predetermined first threshold value a And a comparison with a predetermined second threshold value b. Such a comparison between the signal level of the push-pull signal and the first threshold value a and the second threshold value b is performed for each unit (that is, the mark section) in which the discrimination recording marks ML2 and MR2 are formed. That is, as for the discrimination mark group MG2 formed on the land track LT, it is determined what each mark interval is like the discrimination mark group MG2 formed on the groove track GT.
　より具体的には、図１１の１番目のグラフは、トラック番号が「ｋ－１」となるランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルを示している。この信号レベルは、第１マーク区間が「＋区間」であり、第２マーク区間が「－区間」であり且つ第３マーク区間が「０区間」であることを示している。 More specifically, the first graph in FIG. 11 shows the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k−1”. ing. This signal level indicates that the first mark section is “+ section”, the second mark section is “− section”, and the third mark section is “0 section”.
　同様に、図１１の２番目のグラフは、トラック番号が「ｋ＋１」となるランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルを示している。この信号レベルは、第１マーク区間が「－区間」であり、第２マーク区間が「隣接でない区間」であり且つ第３マーク区間が「＋区間」であることを示している。 Similarly, the second graph of FIG. 11 shows the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 1”. This signal level indicates that the first mark section is a “− section”, the second mark section is a “non-adjacent section”, and the third mark section is a “+ section”.
　同様に、図１１の３番目のグラフは、トラック番号が「ｋ＋３」となるランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルを示している。この信号レベルは、第１マーク区間が「０区間」であり、第２マーク区間が「＋区間」であり且つ第３マーク区間が「－区間」であることを示している。 Similarly, the third graph of FIG. 11 shows the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 3”. This signal level indicates that the first mark section is “0 section”, the second mark section is “+ section”, and the third mark section is “−section”.
　その後、各マーク区間の判定結果の組み合わせに応じて、ガイドレーザ光ＬＢ１がトレースしているランドトラックＬＴがセンタートラックＣＴであるか否かが判別される。 Thereafter, whether or not the land track LT traced by the guide laser beam LB1 is the center track CT is determined according to the combination of the determination results of the respective mark sections.
　具体的には、図１２に示すように、まず、第１マーク区間が「－区間」であるか否かが判定される（ステップＳ２１）。 Specifically, as shown in FIG. 12, first, it is determined whether or not the first mark section is “−section” (step S21).
　ステップＳ２１の判定の結果、第１マーク区間が「－区間」であると判定される場合には（ステップＳ２１：Ｙｅｓ）、続いて、第３マーク区間が「＋区間」であるか否かが判定される（ステップＳ２２）。 As a result of the determination in step S21, when it is determined that the first mark section is “−section” (step S21: Yes), it is subsequently determined whether the third mark section is “+ section” or not. Determination is made (step S22).
　ステップＳ２２の判定の結果、第３マーク区間が「＋区間」であると判定される場合には（ステップＳ２２：Ｙｅｓ）、ガイドレーザ光ＬＢ１が現在トレースしているランドトラックＬＴがセンタートラックＣＴであると判別される（ステップＳ２３）。 As a result of the determination in step S22, when it is determined that the third mark section is “+ section” (step S22: Yes), the land track LT currently traced by the guide laser beam LB1 is the center track CT. It is determined that there is (step S23).
　他方で、ステップＳ２２の判定の結果、第３マーク区間が「＋区間」でないと判定される場合には（ステップＳ２２：Ｎｏ）、続いて、第３マーク区間が「＋不定区間」であるか否かが判定される（ステップＳ２６）。 On the other hand, as a result of the determination in step S22, if it is determined that the third mark section is not “+ section” (step S22: No), then, is the third mark section “+ indefinite section”? It is determined whether or not (step S26).
　ステップＳ２６の判定の結果、第３マーク区間が「＋不定区間」であると判定される場合には（ステップＳ２６：Ｙｅｓ）、ガイドレーザ光ＬＢ１が現在トレースしているランドトラックＬＴがセンタートラックＣＴであると判別される（ステップＳ２３）。 As a result of the determination in step S26, when it is determined that the third mark section is “+ undefined section” (step S26: Yes), the land track LT currently being traced by the guide laser beam LB1 is the center track CT. (Step S23).
　他方で、ステップＳ２６の判定の結果、第３マーク区間が「＋不定区間」でないと判定される場合には（ステップＳ２６：Ｎｏ）、ガイドレーザ光ＬＢ１が現在トレースしているランドトラックＬＴがセンタートラックＣＴでないと判別される（ステップＳ２７）。 On the other hand, as a result of the determination in step S26, if it is determined that the third mark section is not “+ indefinite section” (step S26: No), the land track LT currently being traced by the guide laser beam LB1 is the center. It is determined that it is not the track CT (step S27).
　他方で、ステップＳ２１の判定の結果、第１マーク区間が「－区間」でないと判定される場合には（ステップＳ２１：Ｎｏ）、続いて、第１マーク区間が「－不定区間」であるか否かが判定される（ステップＳ２４）。 On the other hand, if it is determined in step S21 that the first mark section is not “−section” (step S21: No), then whether the first mark section is “−indefinite section” or not. It is determined whether or not (step S24).
　ステップＳ２４の判定の結果、第１マーク区間が「－不定区間」であると判定される場合には（ステップＳ２４：Ｙｅｓ）、続いて、第２マーク区間が「隣接ではない区間」であるか否かが判定される（ステップＳ２５）。 As a result of the determination in step S24, if it is determined that the first mark section is “−indefinite section” (step S24: Yes), then whether the second mark section is “non-adjacent section” or not. It is determined whether or not (step S25).
　ステップＳ２５の判定の結果、第２マーク区間が「隣接ではない区間」であると判定される場合には（ステップＳ２５：Ｙｅｓ）、ステップＳ２２以降の動作が行われる。 As a result of the determination in step S25, when it is determined that the second mark section is “a section that is not adjacent” (step S25: Yes), the operations in and after step S22 are performed.
　他方で、ステップＳ２５の判定の結果、第２マーク区間が「隣接ではない区間」でないと判定される場合には（ステップＳ２５：Ｎｏ）、ガイドレーザ光ＬＢ１が現在トレースしているランドトラックＬＴがセンタートラックＣＴでないと判別される（ステップＳ２７）。 On the other hand, as a result of the determination in step S25, if it is determined that the second mark section is not “a non-adjacent section” (step S25: No), the land track LT currently being traced by the guide laser beam LB1 is determined. It is determined that the track is not the center track CT (step S27).
　他方で、ステップＳ２４の判定の結果、第１マーク区間が「－不定区間」でないと判定される場合には（ステップＳ２４：Ｎｏ）、ガイドレーザ光ＬＢ１がトレースしているランドトラックＬＴがセンタートラックＣＴでないと判別される（ステップＳ２７）。 On the other hand, as a result of the determination in step S24, if it is determined that the first mark section is not “−indefinite section” (step S24: No), the land track LT traced by the guide laser beam LB1 is the center track. It is determined that it is not CT (step S27).
　図１２に示す動作を図１１に示す判別用マーク群ＭＧ２に具体的に適用した場合の例について、以下に説明する。 An example in which the operation shown in FIG. 12 is specifically applied to the discrimination mark group MG2 shown in FIG. 11 will be described below.
　トラック番号が「ｋ－１」となるランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「＋区間」であり、第２マーク区間が「－区間」であり且つ第３マーク区間が「０区間」であることを示している。従って、この場合には、第１マーク区間が－区間でない（ステップＳ２１：Ｎｏ）と判定され且つ第１マーク区間が－不定区間でない（ステップＳ２４：Ｎｏ）と判定される。従って、ガイドレーザ光ＬＢ１が現在トレースしているランドトラックＬＴ（つまり、トラック番号が「ｋ－１」となるランドトラックＬＴ）がセンタートラックＣＴでないと判別される（ステップＳ２７）。 The signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k−1” is the “+ section” in the first mark section, and the second mark This indicates that the section is “−section” and the third mark section is “0 section”. Accordingly, in this case, it is determined that the first mark section is not a −section (step S21: No), and the first mark section is not a −indefinite section (step S24: No). Accordingly, it is determined that the land track LT currently traced by the guide laser beam LB1 (that is, the land track LT with the track number “k−1”) is not the center track CT (step S27).
　続いて、トラック番号が「ｋ＋１」となるランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「－区間」であり、第２マーク区間が「隣接ではない区間」であり且つ第３マーク区間が「＋区間」であることを示している。従って、この場合には、第１マーク区間が－区間である（ステップＳ２１：Ｙｅｓ）と判定され且つ第３マーク区間が＋区間である（ステップＳ２２：Ｙｅｓ）と判定される。従って、ガイドレーザ光ＬＢ１が現在トレースしているランドトラックＬＴ（つまり、トラック番号が「ｋ＋１」となるランドトラックＬＴ）がセンタートラックＣＴであると判別される（ステップＳ２３）。 Subsequently, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 1” is the “−section” in the first mark section, The mark section is “a section that is not adjacent”, and the third mark section is “+ section”. Therefore, in this case, it is determined that the first mark section is the-section (step S21: Yes) and the third mark section is the + section (step S22: Yes). Accordingly, it is determined that the land track LT currently traced by the guide laser beam LB1 (that is, the land track LT with the track number “k + 1”) is the center track CT (step S23).
　同様に、トラック番号が「ｋ＋３」となるランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「０区間」であり、第２マーク区間が「＋区間」であり且つ第３マーク区間が「－区間」であることを示している。従って、この場合には、第１マーク区間が－区間でない（ステップＳ２１：Ｎｏ）と判定され且つ第１マーク区間が－不定区間でない（ステップＳ２４：Ｎｏ）と判定される。従って、ガイドレーザ光ＬＢ１が現在トレースしているランドトラックＬＴ（つまり、トラック番号が「ｋ＋３」となるランドトラックＬＴ）がセンタートラックＣＴでないと判別される（ステップＳ２７）。 Similarly, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 3” is “0 section” in the first mark section, The mark section is “+ section” and the third mark section is “− section”. Accordingly, in this case, it is determined that the first mark section is not a −section (step S21: No), and the first mark section is not a −indefinite section (step S24: No). Accordingly, it is determined that the land track LT currently traced by the guide laser beam LB1 (that is, the land track LT with the track number “k + 3”) is not the center track CT (step S27).
　このように、判別用マーク群ＭＧ２を用いて、センタートラックＣＴが好適に判別される。 Thus, the center track CT is suitably discriminated using the discrimination mark group MG2.
　尚、図１０及び図１１に示す判別用マーク群ＭＧ２の態様はあくまで一例である。従って、図１０及び図１１に示す態様以外の態様を示す判別用マーク群ＭＧ２（つまり、同一の回転位相位置に形成される一対の判別用記録マークＭＬ２及びＭＲ２並びに異なる回転位相位置に形成される一対の判別用記録マークＭＬ２及びＭＲ２の少なくとも一方を一つ以上含む任意の判別用マーク群ＭＧ２）を用いて、センタートラックＣＴが判別されてもよい。この場合、当然に、図１２に示すフローチャートも、図１０及び図１１に示す態様以外の態様を示す判別用マーク群ＭＧ２に合わせて変更されることが好ましい。 Note that the mode of the discrimination mark group MG2 shown in FIGS. 10 and 11 is merely an example. Accordingly, a discrimination mark group MG2 showing a mode other than the modes shown in FIGS. 10 and 11 (that is, a pair of discrimination recording marks ML2 and MR2 formed at the same rotational phase position and different rotational phase positions). The center track CT may be discriminated using an arbitrary discriminating mark group MG2) including at least one of the pair of discriminating recording marks ML2 and MR2. Naturally, in this case, it is preferable that the flowchart shown in FIG. 12 is also changed in accordance with the determination mark group MG2 showing an aspect other than the aspects shown in FIGS.
　（２－３）情報用マーク群及び判別用マーク群の分布の態様
　続いて、図１３から図１５を参照して、ガイド層１２に形成されている情報用マーク群ＭＧ１及び判別用マーク群ＭＧ２の分布の態様について説明する。図１３は、ガイド層１２（更には、記録層１３）のデータ構造を示すデータ構造図である。図１４は、特定のスロットに形成される情報用マーク群ＭＧ１及び判別用マーク群ＭＧ２の一例を示す平面図である。図１５は、複数の情報用マーク群ＭＧ１及び複数の判別用マーク群ＭＧ２が複数のスロットに分散して記録される態様を示す平面図である。 (2-3) Distribution Mode of Information Mark Group and Discrimination Mark Group Subsequently, with reference to FIGS. 13 to 15, the information mark group MG1 and the discrimination mark group MG2 formed on the guide layer 12 The distribution mode will be described. FIG. 13 is a data structure diagram showing the data structure of the guide layer 12 (and also the recording layer 13). FIG. 14 is a plan view showing an example of the information mark group MG1 and the discrimination mark group MG2 formed in a specific slot. FIG. 15 is a plan view showing an aspect in which a plurality of information mark groups MG1 and a plurality of determination mark groups MG2 are recorded in a plurality of slots.
　図１３に示すように、記録層１３は、ＥＣＣブロックという単位で区分される。つまり、記録層１３上に記録される記録情報は、ＥＣＣブロックという単位で記録される。このため、記録層１３と同様に、ガイド層１２もまた、ＥＣＣブロックという単位で区分される。つまり、ガイド層１２上に記録されるプリフォーマット情報（例えば、アドレス情報やクロック情報や記録開始タイミング情報等）は、ＥＣＣブロックという単位で記録される。 As shown in FIG. 13, the recording layer 13 is divided into units called ECC blocks. That is, the recording information recorded on the recording layer 13 is recorded in units of ECC blocks. For this reason, like the recording layer 13, the guide layer 12 is also divided in units of ECC blocks. That is, preformat information (for example, address information, clock information, recording start timing information, etc.) recorded on the guide layer 12 is recorded in units of ECC blocks.
　１個のＥＣＣブロックは、２個のワードという単位に細分化される。１個のワードは、４０個のグループ又は４３個のグループという単位に細分化される。１個のグループは、８個のスロットという単位に細分化される。１個のスロットは、２１ウォブルに相当するサイズを有している。尚、ここでいう「ウォブル」とは、例えば、Ｂｌｕ－ｒａｙ規格で規定されているウォブルを示すものとする。
２１ウォブルのうちヘッダに相当する３ウォブル及びフッタに相当３ウォブルは、夫々、隣接するスロットとの間の干渉を防ぐための緩衝領域に相当する。従って、１個のスロットには、実質的には、最大で１５ウォブルに相当するサイズの情報を記録することができる。 One ECC block is subdivided into units of two words. One word is subdivided into units of 40 groups or 43 groups. One group is subdivided into units of 8 slots. One slot has a size corresponding to 21 wobbles. The “wobble” here refers to, for example, a wobble defined in the Blu-ray standard.
Of the 21 wobbles, 3 wobbles corresponding to the header and 3 wobbles corresponding to the footer each correspond to a buffer area for preventing interference with adjacent slots. Accordingly, information of a size corresponding to a maximum of 15 wobbles can be recorded in one slot.
　図１４に示すように、２つの同期データ及び３つのビットデータを示す５種類の情報用マーク群ＭＧ１は、１５ウォブルのうちの１０ウォブルを用いて形成される。加えて、図１４に示すように、３つのビットデータを示す３種類の情報用マーク群ＭＧ１が形成されている３つのグルーブトラックＧＴのうちのセンタートラックＣＴを判別するための判別用マーク群ＭＧ２は、１５ウォブルのうちの２ウォブルを用いて形成される。つまり、図８に示す例では、１個のスロットには、３ビットのビットデータを記録することができる。 As shown in FIG. 14, five types of information mark groups MG1 indicating two synchronization data and three bit data are formed using 10 wobbles out of 15 wobbles. In addition, as shown in FIG. 14, a discrimination mark group MG2 for discriminating the center track CT among the three groove tracks GT on which the three types of information mark groups MG1 indicating the three bit data are formed. Is formed using 2 out of 15 wobbles. That is, in the example shown in FIG. 8, 3-bit bit data can be recorded in one slot.
　図１４に示す例では、３つのビットデータを示す３種類の情報用マーク群ＭＧ１の夫々が形成されている３つのグルーブトラックＧＴのうちのセンタートラックＣＴを判別するために、１つの判別用マーク群ＭＧ２が用いられる。従って、図１４に示す判別用マーク群ＭＧ２によってセンタートラックＣＴが判別された後には、図１４に示す３つのビットデータを示す３種類の情報用マーク群ＭＧ１が読み取られる。尚、他のスロットに形成された他の情報用マーク群ＭＧ１の夫々が形成されている３つのグルーブトラックＧＴのうちのセンタートラックＣＴを判別するためには、当該他のスロットに形成された他の判別用マーク群ＭＧ２が用いられる。つまり、本実施例では、情報用マーク群ＭＧ１と判別用マーク群ＭＧ２とは、スロット単位で対応付けられている。但し、情報用マーク群ＭＧ１と判別用マーク群ＭＧ２とは、スロット単位以外のその他の単位で対応付けられていてもよい。 In the example shown in FIG. 14, one discrimination mark is used to discriminate the center track CT among the three groove tracks GT in which each of the three types of information mark groups MG1 representing three bit data is formed. Group MG2 is used. Therefore, after the center track CT is discriminated by the discriminating mark group MG2 shown in FIG. 14, three types of information mark groups MG1 showing the three bit data shown in FIG. 14 are read. In order to determine the center track CT among the three groove tracks GT on which the other information mark groups MG1 formed in the other slots are formed, the other information formed in the other slots The discriminating mark group MG2 is used. That is, in this embodiment, the information mark group MG1 and the discrimination mark group MG2 are associated with each other in slot units. However, the information mark group MG1 and the discrimination mark group MG2 may be associated with other units other than the slot unit.
　図１５に示すように、本実施例では、このようなスロットの単位を利用して、異なる情報用データ群ＭＧ１が同一のグルーブトラックＧＴ又は同一のランドトラックＬＴの同一の回転位相位置に重複して形成されないように構成される。加えて、このようなスロットの単位を利用して、異なる判別用データ群ＭＧ２が同一のグルーブトラックＧＴ又は同一のランドトラックＬＴの同一の回転位相位置に重複して形成されないように構成される。以下、トラック番号が「ｋ」となるガイドトラックＴＲを中心とする複数のガイドトラックＴＲの夫々の同一の回転位相位置に形成される情報用マーク群ＭＧ１及び当該情報用マーク群ＭＧ１に対応付けられている判別用マーク群ＭＧ２を、マーク群ＭＧ（ｋ）と称して説明を進める。 As shown in FIG. 15, in this embodiment, using such a slot unit, different information data groups MG1 are overlapped at the same rotational phase position of the same groove track GT or the same land track LT. It is configured not to be formed. In addition, by using such a slot unit, different discrimination data groups MG2 are configured not to be duplicated at the same rotational phase position of the same groove track GT or the same land track LT. Hereinafter, the information mark group MG1 formed at the same rotational phase position of each of the plurality of guide tracks TR centering on the guide track TR having the track number “k” and the information mark group MG1 are associated with each other. The determination mark group MG2 is referred to as a mark group MG (k), and the description will proceed.
　図１５に示すように、マーク群ＭＧ（ｋ）がスロット＃１に形成されているとする。この場合、マーク群ＭＧ（ｋ）は、トラック番号が「ｋ」となるグルーブトラックＧＴのみならず、トラック番号が「ｋ－２」となるグルーブトラックＧＴ及びトラック番号が「ｋ＋２」となるグルーブトラックＧＴにも同様に形成されている。従って、マーク群ＭＧ（ｋ）以外の他のマーク群ＭＧは、トラック番号が「ｋ－２」となるグルーブトラックＧＴからトラック番号が「ｋ＋２」となるグルーブトラックＧＴに至るまでのガイドトラックＴＲ上のスロット＃１の位置には形成されない。これにより、マーク群ＭＧ（ｋ）と当該マーク群ＭＧ（ｋ）以外の他のマーク群ＭＧとが、同一のガイドトラックＴＲ上の同一回転位相位置に重複的に形成されることはなくなる。 Suppose that mark group MG (k) is formed in slot # 1 as shown in FIG. In this case, the mark group MG (k) includes not only the groove track GT with the track number “k”, but also the groove track GT with the track number “k−2” and the groove track with the track number “k + 2”. It is similarly formed in GT. Therefore, the mark group MG other than the mark group MG (k) is on the guide track TR from the groove track GT with the track number “k−2” to the groove track GT with the track number “k + 2”. It is not formed at the position of slot # 1. As a result, the mark group MG (k) and the mark group MG other than the mark group MG (k) are not repeatedly formed at the same rotational phase position on the same guide track TR.
　一方で、マーク群ＭＧ（ｋ）以外の他のマーク群ＭＧは、トラック番号が「ｋ－２」となるグルーブトラックＧＴからトラック番号が「ｋ＋２」となるグルーブトラックＧＴに至るまでのガイドトラックＴＲ上であっても、スロット＃１以外のスロットには形成されてもよい。つまり、本実施例では、あるマーク群ＭＧ（ｋ）と、当該マーク群ＭＧ（ｋ）が形成されるガイドトラックＴＲと同一のガイドトラックＴＲ上に形成される他のマーク群ＭＧ（例えば、マーク群ＭＧ（ｋ－４）からマーク群ＭＧ（ｋ－１）及びマーク群ＭＧ（ｋ＋１）からマーク群ＭＧ（ｋ＋４））とは、別々のスロットに形成されることが好ましい。これにより、マーク群ＭＧ（ｋ）と当該マーク群ＭＧ（ｋ）以外の他のマーク群ＭＧとが、同一のガイドトラックＴＲ上の同一回転位相位置に重複的に形成されることはなくなる。 On the other hand, the other mark groups MG other than the mark group MG (k) are guided track TR from the groove track GT having the track number “k−2” to the groove track GT having the track number “k + 2”. Even above, it may be formed in slots other than slot # 1. That is, in this embodiment, a certain mark group MG (k) and another mark group MG (for example, a mark group MG) formed on the same guide track TR as the guide track TR on which the mark group MG (k) is formed. Group MG (k-4) to mark group MG (k-1) and mark group MG (k + 1) to mark group MG (k + 4)) are preferably formed in separate slots. As a result, the mark group MG (k) and the mark group MG other than the mark group MG (k) are not repeatedly formed at the same rotational phase position on the same guide track TR.
　例えば、図１５は、ＭＧ（ｋ－１）が、トラック番号が「ｋ－３」となるランドトラックＬＴ、トラック番号が「ｋ－１」となるランドトラックＬＴ及びトラック番号が「ｋ＋１」となるランドトラックＬＴのスロット＃８の位置に形成される例を示している。同様に、例えば、図１５は、ＭＧ（ｋ＋１）が、トラック番号が「ｋ－１」となるランドトラックＬＴ、トラック番号が「ｋ＋１」となるランドトラックＬＴ及びトラック番号が「ｋ＋３」となるランドトラックＬＴのスロット＃２の位置に形成される例を示している。同様に、例えば、図１５は、ＭＧ（ｋ＋２）が、トラック番号が「ｋ」となるグルーブトラックＧＴ、トラック番号が「ｋ＋２」となるグルーブトラックＧＴ及びトラック番号が「ｋ＋４」となるグルーブトラックＧＴのスロット＃３の位置に形成される例を示している。同様に、例えば、図１５は、ＭＧ（ｋ＋３）が、トラック番号が「ｋ＋１」となるランドトラックＬＴ、トラック番号が「ｋ＋３」となるランドトラックＬＴ及びトラック番号が「ｋ＋５」となるランドトラックＬＴのスロット＃４の位置に形成される例を示している。同様に、例えば、図１５は、ＭＧ（ｋ＋４）が、トラック番号が「ｋ＋２」となるグルーブトラックＧＴ、トラック番号が「ｋ＋４」となるグルーブトラックＧＴ及びトラック番号が「ｋ＋６」となるグルーブトラックＧＴのスロット＃５の位置に形成される例を示している。このように、マーク群ＭＧが形成される回転半径位置をスロットの単位で区別することで、トラック番号が「ｋ－２」となるグルーブトラックＧＴからトラック番号が「ｋ＋２」となるグルーブトラックＧＴに至るまでのガイドトラックＴＲに一部の記録マークが形成されることになるマーク群ＭＧ（ｋ－１）からマーク群ＭＧ（ｋ＋４）は、互いに重複する位置（つまり、同一回転半径位置）に形成されなくなる。 For example, in FIG. 15, MG (k−1) is a land track LT with a track number “k-3”, a land track LT with a track number “k−1”, and a track number “k + 1”. An example is shown in which it is formed at the position of slot # 8 of the land track LT. Similarly, for example, FIG. 15 shows that MG (k + 1) is a land track LT with a track number “k−1”, a land track LT with a track number “k + 1”, and a land track LT with a track number “k + 3”. An example is shown in which it is formed at the position of slot # 2 of the track LT. Similarly, for example, FIG. 15 shows that MG (k + 2) is a groove track GT with a track number “k”, a groove track GT with a track number “k + 2”, and a groove track GT with a track number “k + 4”. In the example shown in FIG. Similarly, for example, FIG. 15 shows that MG (k + 3) is a land track LT with a track number “k + 1”, a land track LT with a track number “k + 3”, and a land track LT with a track number “k + 5”. In the example shown in FIG. Similarly, for example, FIG. 15 shows that MG (k + 4) is a groove track GT with a track number “k + 2”, a groove track GT with a track number “k + 4”, and a groove track GT with a track number “k + 6”. In the example shown in FIG. Thus, by distinguishing the rotational radius position where the mark group MG is formed in slot units, the groove track GT with the track number “k−2” is changed to the groove track GT with the track number “k + 2”. The mark groups MG (k−1) to MG (k + 4) in which a part of the recording marks are formed on the guide tracks TR are formed at positions overlapping each other (that is, at the same rotational radius position). It will not be done.
　ここで、記録再生装置１００が、トラック番号が「ｋ」となるグルーブトラックＧＴ（以降、適宜“グルーブトラックＧＴ（ｋ）”と称する）をトレースする場合の動作について簡単に説明する。この場合、記録再生装置１００は、スロット＃１に形成されたマーク群ＭＧ（ｋ）に含まれる判別用マーク群ＭＧ２によって、グルーブトラックＧＴ（ｋ）がセンタートラックＣＴであると判別する。その後、記録再生装置１００は、マーク群ＭＧ（ｋ）に含まれる情報用マーク群ＭＧ１からビットデータ等を読み取る。その後も、記録再生装置１００はルーブトラックＧＴ（ｋ）のトレースを継続する。このとき、記録再生装置１００は、スロット＃２からスロット＃８に形成されたマーク群ＭＧ（２）からＭＧ（８）をも読み取る可能性がある。しかしながら、スロット＃２からスロット＃８に形成されたマーク群ＭＧ（２）からＭＧ（８）に含まれる判別用マーク群ＭＧ２によれば、グルーブトラックＧＴ（ｋ）がセンタートラックＣＴでないと判別される。従って、記録再生装置１００は、スロット＃２からスロット＃８に形成されたマーク群ＭＧ（２）からＭＧ（８）に含まれる情報用マーク群ＭＧ１からビットデータ等を読み取らない。つまり、記録再生装置１００は、現在トレースしているガイドトラックＴＲがセンタートラックＣＴであると判別された場合にのみ、当該判別用マーク群ＭＧ２に対応付けられた（言い換えれば、同一スロットに含まれている）情報用マーク群ＭＧ１が示すビットデータを読み取る。 Here, the operation when the recording / reproducing apparatus 100 traces the groove track GT (hereinafter referred to as “groove track GT (k)” where the track number is “k”) will be briefly described. In this case, the recording / reproducing apparatus 100 determines that the groove track GT (k) is the center track CT based on the determination mark group MG2 included in the mark group MG (k) formed in the slot # 1. Thereafter, the recording / reproducing apparatus 100 reads bit data and the like from the information mark group MG1 included in the mark group MG (k). Thereafter, the recording / reproducing apparatus 100 continues tracing the lube track GT (k). At this time, the recording / reproducing apparatus 100 may also read the mark groups MG (2) to MG (8) formed in the slot # 2 to the slot # 8. However, according to the determination mark group MG2 included in the mark groups MG (2) to MG (8) formed in the slot # 2 to the slot # 8, it is determined that the groove track GT (k) is not the center track CT. The Therefore, the recording / reproducing apparatus 100 does not read bit data or the like from the information mark group MG1 included in the mark groups MG (2) to MG (8) formed in the slot # 2 to the slot # 8. That is, the recording / reproducing apparatus 100 is associated with the determination mark group MG2 only when the currently tracked guide track TR is determined to be the center track CT (in other words, included in the same slot). The bit data indicated by the information mark group MG1 is read.
　ここで、判別用マーク群ＭＧ２が形成されていない比較例の光ディスクについて説明する。比較例の光ディスクにおいても、記録再生装置１００は、グルーブトラックＧＴ（ｋ）をトレースすることでスロット＃１に形成されたマーク群ＭＧ（ｋ）に含まれる情報用マーク群ＭＧ１からビットデータ等を読み取ることができる。しかしながら、比較例の光ディスクでは、記録再生装置１００は、グルーブトラックＧＴ（ｋ）とは異なるグルーブトラックＧＴ（ｋ－２）やグルーブトラックＧＴ（ｋ＋２）をトレースしても、スロット＃１に形成されたマーク群ＭＧ（ｋ）に含まれる情報用マーク群ＭＧ１を読み取ることができる。この場合、仮に情報用マーク群ＭＧ１が示すビットデータがアドレス情報である場合には、記録再生装置１００は、現在トレースしている箇所のアドレス情報を誤認識してしまうおそれがある。つまり、記録再生装置１００は、本来グルーブトラックＧＴ（ｋ＋２）をトレースしているにも関わらず、グルーブトラックＧＴ（ｋ）をトレースしていると誤って認識してしまうおそれがある。その結果、適切な記録動作や適切な再生動作が行われないおそれがある。しかるに、本実施例では、記録再生装置１００は、グルーブトラックＧＴ（ｋ）とは異なるグルーブトラックＧＴ（ｋ－２）やグルーブトラックＧＴ（ｋ＋２）をトレースしても、スロット＃１に形成されたマーク群ＭＧ（ｋ）に含まれる情報用マーク群ＭＧ１を読み取ることがない。従って、比較例の光ディスクで生ずる技術的問題は生じない。 Here, an optical disk of a comparative example in which the discrimination mark group MG2 is not formed will be described. Also in the optical disc of the comparative example, the recording / reproducing apparatus 100 traces the groove track GT (k) to obtain bit data or the like from the information mark group MG1 included in the mark group MG (k) formed in the slot # 1. Can be read. However, in the optical disk of the comparative example, the recording / reproducing apparatus 100 is formed in the slot # 1 even if the groove track GT (k-2) or the groove track GT (k + 2) different from the groove track GT (k) is traced. The information mark group MG1 included in the mark group MG (k) can be read. In this case, if the bit data indicated by the information mark group MG1 is address information, the recording / reproducing apparatus 100 may erroneously recognize the address information of the currently traced location. That is, the recording / reproducing apparatus 100 may erroneously recognize that the groove track GT (k) is being traced although the groove track GT (k + 2) is originally being traced. As a result, there is a possibility that an appropriate recording operation and an appropriate reproduction operation are not performed. However, in this embodiment, the recording / reproducing apparatus 100 is formed in the slot # 1 even if the groove track GT (k-2) or the groove track GT (k + 2) different from the groove track GT (k) is traced. The information mark group MG1 included in the mark group MG (k) is not read. Therefore, the technical problem which arises with the optical disk of a comparative example does not arise.
　尚、情報用記録マークＭＬ１及びＭＲ１のトラック中心からのシフト量は、全ての情報用マーク群ＭＧ１において統一されていてもよいし、情報用マーク群ＭＧ１毎に異なっていてもよい。例えば、図１５に示す例で言えば、マーク群ＭＧ（ｋ）に含まれる情報用マーク群ＭＧ１を構成する情報用記録マークＭＬ１及びＭＲ１のトラック中心からのシフト量は、マーク群ＭＧ（ｋ）以外の他のマーク群ＭＧに含まれる情報用マーク群ＭＧ１を構成する情報用記録マークＭＬ１及びＭＲ１のトラック中心からのシフト量と同一であってもよいし、異なっていてもよい。要は、情報用マーク群ＭＧ１を構成する情報用記録マークＭＬ１及びＭＲ１のトラック中心からのシフト量は、少なくとも同一の情報用マーク群ＭＧ１内において統一されていれば足りる。例えば、マーク群ＭＧ（ｋ）に含まれる情報用マーク群ＭＧ１を構成する情報用記録マークＭＬ１及びＭＲ１のトラック中心からのシフト量は、少なくともマーク群ＭＧ（ｋ）に含まれる情報用マーク群ＭＧ１内において統一されていれば足りる。 Note that the shift amounts of the information recording marks ML1 and MR1 from the track center may be unified in all the information mark groups MG1, or may be different for each information mark group MG1. For example, in the example shown in FIG. 15, the shift amount from the track center of the information recording marks ML1 and MR1 constituting the information mark group MG1 included in the mark group MG (k) is the mark group MG (k). The shift amounts from the track center of the information recording marks ML1 and MR1 constituting the information mark group MG1 included in the other mark group MG may be the same or different. In short, it is sufficient that the shift amounts from the track center of the information recording marks ML1 and MR1 constituting the information mark group MG1 are at least unified within the same information mark group MG1. For example, the shift amount from the track center of the information recording marks ML1 and MR1 constituting the information mark group MG1 included in the mark group MG (k) is at least the information mark group MG1 included in the mark group MG (k). It is sufficient if they are unified within the company.
　また、判別用記録マークＭＬ２及びＭＲ２のセンタートラックＣＴのトラック中心からのシフト量は、全ての判別用マーク群ＭＧ２において統一されていてもよいし、判別用マーク群ＭＧ２毎に異なっていてもよい。例えば、図１５に示す例で言えば、マーク群ＭＧ（ｋ）に含まれる判別用マーク群ＭＧ２を構成する判別用記録マークＭＬ２及びＭＲ２のセンタートラックＣＴのトラック中心からのシフト量は、マーク群ＭＧ（ｋ）以外の他のマーク群ＭＧに含まれる判別用マーク群ＭＧ２を構成する判別用記録マークＭＬ２及びＭＲ２のセンタートラックＣＴのトラック中心からのシフト量と同一であってもよいし、異なっていてもよい。或いは、判別用記録マークＭＬ２及びＭＲ２のセンタートラックＣＴのトラック中心からのシフト量は、同一の判別用マーク群ＭＧ２内においても異なっていてもよい。例えば、図１５に示す例で言えば、マーク群ＭＧ（ｋ）に含まれる判別用マーク群ＭＧ２を構成する第１の判別用記録マークＭＬ２及びＭＲ２のセンタートラックＣＴのトラック中心からのシフト量は、マーク群ＭＧ（ｋ）に含まれる判別用マーク群ＭＧ２を構成する第２の判別用記録マークＭＬ２及びＭＲ２のセンタートラックＣＴのトラック中心からのシフト量と異なっていてもよい。 Further, the shift amounts of the discrimination recording marks ML2 and MR2 from the center of the center track CT may be unified in all discrimination mark groups MG2, or may be different for each discrimination mark group MG2. . For example, in the example shown in FIG. 15, the shift amount from the track center of the center track CT of the discrimination recording marks ML2 and MR2 constituting the discrimination mark group MG2 included in the mark group MG (k) is expressed as follows. The shift amount from the track center of the center track CT of the discrimination recording marks ML2 and MR2 constituting the discrimination mark group MG2 included in the other mark group MG other than MG (k) may be the same or different. It may be. Alternatively, the shift amounts of the discrimination recording marks ML2 and MR2 from the track center of the center track CT may be different within the same discrimination mark group MG2. For example, in the example shown in FIG. 15, the shift amount from the track center of the center track CT of the first discrimination recording mark ML2 and MR2 constituting the discrimination mark group MG2 included in the mark group MG (k) is The shift amount from the track center of the center track CT of the second discrimination recording marks ML2 and MR2 constituting the discrimination mark group MG2 included in the mark group MG (k) may be different.
　（２－４）情報用マーク群及び判別用マーク群の特性
　続いて、本実施例の情報用マーク群ＭＧ１及び判別用マーク群ＭＧ２の特性について説明する。 (2-4) Characteristics of Information Mark Group and Discrimination Mark Group Next, the characteristics of the information mark group MG1 and the discrimination mark group MG2 of this embodiment will be described.
　まず、上述したように、情報用マーク群ＭＧ１及び判別用マーク群ＭＧ２の形成の有無に関わらず、ガイドトラックＴＲ上をトレースするガイドレーザ光ＬＢ１の戻り光からは、ガイドレーザ光ＬＢ１のビームスポットの中心とガイドトラックＴＲのトラック中心との間の位置関係に応じたプッシュプル信号が得られる。その結果、当該プッシュプル信号に基づくトラッキング制御が行われる。 First, as described above, regardless of the formation of the information mark group MG1 and the determination mark group MG2, the beam spot of the guide laser beam LB1 is derived from the return beam of the guide laser beam LB1 that traces on the guide track TR. And a push-pull signal corresponding to the positional relationship between the center of the guide track TR and the track center of the guide track TR. As a result, tracking control based on the push-pull signal is performed.
　一方で、情報用マーク群ＭＧ１が形成されたガイドトラックＴＲ上をトレースするガイドレーザ光ＬＢ１の戻り光から得られるプッシュプル信号の信号レベルは、情報用マーク群ＭＧ１を構成する情報用記録マークＭＬ１及びＭＲ１のパターンに応じて変動する（例えば、図４及び図６参照）。つまり、本実施例では、プッシュプル信号の信号レベルは、ガイドレーザ光ＬＢ１のビームスポットのスポット中心と情報用マーク群ＭＧ１を構成する情報用記録マークＭＬ１及びＭＲ２との間の位置関係に応じて変動する。しかしながら、情報用マーク群ＭＧ１が、トラック中心から左右に等距離シフトした一対の情報用記録マークＭＬ１及びＭＲ１が組み合わせられた情報用マーク群ＭＧ１であるため、プッシュプル信号の信号レベルの変動の平均値（言い換えれば、積分値）は、ゼロになる。従って、情報用マーク群ＭＧ１がガイドトラックＴＲ上に形成されたとしても、当該情報用マーク群ＭＧ１が、プッシュプル信号に基づくトラッキング制御に大きな悪影響（例えば、正常なトラッキング制御を行うことができない程度の悪影響）を及ぼすことは殆ど又は全くない。従って、情報用マーク群ＭＧ１がガイドトラックＴＲ上に形成されたとしても、情報用マーク群ＭＧ１がガイドトラックＴＲ上に形成されていない場合と概ね同様に、好適なトラッキング制御が行われる。 On the other hand, the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 traced on the guide track TR on which the information mark group MG1 is formed is the information recording mark ML1 constituting the information mark group MG1. And fluctuate according to the pattern of MR1 (see, for example, FIGS. 4 and 6). That is, in this embodiment, the signal level of the push-pull signal depends on the positional relationship between the spot center of the beam spot of the guide laser beam LB1 and the information recording marks ML1 and MR2 constituting the information mark group MG1. fluctuate. However, since the information mark group MG1 is an information mark group MG1 in which a pair of information recording marks ML1 and MR1 that are shifted equidistant from the center of the track to the left and right are combined, the average of the signal level fluctuation of the push-pull signal is averaged. The value (in other words, the integral value) becomes zero. Therefore, even if the information mark group MG1 is formed on the guide track TR, the information mark group MG1 has a large adverse effect on tracking control based on the push-pull signal (for example, normal tracking control cannot be performed). Little or no adverse effects). Accordingly, even if the information mark group MG1 is formed on the guide track TR, suitable tracking control is performed in substantially the same manner as when the information mark group MG1 is not formed on the guide track TR.
　それでいて、上述したように、プッシュプル信号の信号レベルの変動から、各種データ（例えば、上述した同期データやビットデータ）が読み取られる。つまり、本実施例では、一対の情報用記録マークＭＬ１及びＭＲ１が組み合わせられた情報用マーク群ＭＧ１をガイド層１２上に形成することで、プッシュプル信号を用いて読み取られる各種データを記録することができる。言い換えれば、本実施例では、一対の情報用記録マークＭＬ１及びＭＲ１が組み合わせられた情報用マーク群ＭＧ１をガイド層１２に形成することで、ＲＦ信号を用いて読み取らなくともよい各種データをガイド層１２に記録することができる。 Nevertheless, as described above, various data (for example, the above-described synchronization data and bit data) are read from the fluctuation of the signal level of the push-pull signal. That is, in this embodiment, the information mark group MG1 in which the pair of information recording marks ML1 and MR1 are combined is formed on the guide layer 12, thereby recording various data read using the push-pull signal. Can do. In other words, in this embodiment, the information mark group MG1 in which the pair of information recording marks ML1 and MR1 are combined is formed on the guide layer 12, and various data that does not need to be read using the RF signal can be obtained from the guide layer. 12 can be recorded.
　加えて、判別用マーク群ＭＧ２が形成されたガイドトラックＴＲ上をトレースするガイドレーザ光ＬＢ１の戻り光から得られるプッシュプル信号の信号レベルは、判別用マーク群ＭＧ２を構成する判別用記録マークＭＬ２及びＭＲ２のパターンに応じて変動する（例えば、図８及び図１１参照）。つまり、本実施例では、プッシュプル信号の信号レベルは、ガイドレーザ光ＬＢ１のビームスポットのスポット中心と判別用マーク群ＭＧ２を構成する判別用記録マークＭＬ２及びＭＬ２との間の位置関係に応じて変動する。しかしながら、判別用マーク群ＭＧ２が、センタートラックＣＴのトラック中心から左右に等距離シフトした一対の判別用記録マークＭＬ２及びＭＲ２が組み合わせられた判別用マーク群ＭＧ２であるため、プッシュプル信号の信号レベルの変動の平均値（言い換えれば、積分値）は、ゼロになる。従って、判別用マーク群ＭＧ２がガイドトラックＴＲ上に形成されたとしても、当該判別用マーク群ＭＧ２が、プッシュプル信号に基づくトラッキング制御に大きな悪影響（例えば、正常なトラッキング制御を行うことができない程度の悪影響）を及ぼすことは殆ど又は全くない。従って、判別用マーク群ＭＧ２がガイドトラックＴＲ上に形成されたとしても、判別用マーク群ＭＧ２がガイドトラックＴＲ上に形成されていない場合と概ね同様に、好適なトラッキング制御が行われる。 In addition, the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 that traces on the guide track TR on which the discrimination mark group MG2 is formed is the discrimination recording mark ML2 that constitutes the discrimination mark group MG2. And fluctuate according to the MR2 pattern (see, for example, FIGS. 8 and 11). That is, in the present embodiment, the signal level of the push-pull signal depends on the positional relationship between the spot center of the beam spot of the guide laser beam LB1 and the discrimination recording marks ML2 and ML2 constituting the discrimination mark group MG2. fluctuate. However, since the discrimination mark group MG2 is a discrimination mark group MG2 in which a pair of discrimination recording marks ML2 and MR2 that are shifted equidistant from the center of the center track CT to the left and right are combined, the signal level of the push-pull signal The average value of the fluctuations (in other words, the integral value) becomes zero. Therefore, even if the discrimination mark group MG2 is formed on the guide track TR, the discrimination mark group MG2 has a large adverse effect on tracking control based on the push-pull signal (for example, normal tracking control cannot be performed). Little or no adverse effects). Therefore, even if the discrimination mark group MG2 is formed on the guide track TR, suitable tracking control is performed in substantially the same manner as when the discrimination mark group MG2 is not formed on the guide track TR.
　それでいて、上述したように、プッシュプル信号の信号レベルの変動から、現在トレースしているガイドトラックＴＲがセンタートラックＣＴであるか否かを好適に判別することができる。つまり、本実施例では、一対の判別用記録マークＭＬ２及びＭＲ２が組み合わせられた判別用マーク群ＭＧ２をガイド層１２上に形成することで、プッシュプル信号を用いたセンタートラックＣＴの判別を実現することができる。言い換えれば、本実施例では、一対の判別用記録マークＭＬ２及びＭＲ２が組み合わせられた判別用マーク群ＭＧ２をガイド層１２に形成することで、ＲＦ信号を用いることなく、センタートラックＣＴの判別を実現することができる。 Nevertheless, as described above, it is possible to suitably determine whether or not the currently tracked guide track TR is the center track CT from the fluctuation of the signal level of the push-pull signal. That is, in this embodiment, the discrimination of the center track CT using the push-pull signal is realized by forming the discrimination mark group MG2 in which the pair of discrimination recording marks ML2 and MR2 are combined on the guide layer 12. be able to. In other words, in this embodiment, the discrimination of the center track CT is realized without using the RF signal by forming the discrimination mark group MG2 in which the pair of discrimination recording marks ML2 and MR2 are combined on the guide layer 12. can do.
　ここで、図１６を参照して、ガイド層１２に形成された情報用マーク群ＭＧ１及び判別用マーク群ＭＧ２を、トラッキング制御に用いられるプッシュプル信号から読み取ることで実現される利点について説明する。図１６は、グルーブトラックＧＴの凹部の深さ（つまり、ランドトラックＬＴに対するグルーブトラックＧＴの相対的な深さ）とプッシュプル信号及びＲＦ信号の信号レベルとの関係を示すグラフである。 Here, with reference to FIG. 16, an advantage realized by reading the information mark group MG1 and the discrimination mark group MG2 formed on the guide layer 12 from a push-pull signal used for tracking control will be described. FIG. 16 is a graph showing the relationship between the depth of the concave portion of the groove track GT (that is, the relative depth of the groove track GT with respect to the land track LT) and the signal levels of the push-pull signal and the RF signal.
　図１６に示すように、トラッキング制御に用いられるプッシュプル信号の信号レベルは、グルーブトラックＧＴの深さがλ／８ｎ（つまり、λ÷（８×ｎ））となる場合に最良となる。一方で、トラッキング制御に用いられないＲＦ信号の信号レベルは、グルーブトラックＧＴの深さがλ／４ｎ（つまり、λ÷（４×ｎ））となる場合に最良となる。仮に、ガイド層１２上に、ＲＦ信号を用いて読み取る必要があるマーク群を形成した場合には、プッシュプル信号の信号レベル（言い換えれば、信号特性）のみならず、ＲＦ信号の信号レベル（信号特性）をも考慮する必要がある。 As shown in FIG. 16, the signal level of the push-pull signal used for tracking control is best when the depth of the groove track GT is λ / 8n (that is, λ ÷ (8 × n)). On the other hand, the signal level of the RF signal that is not used for tracking control is best when the depth of the groove track GT is λ / 4n (that is, λ ÷ (4 × n)). If a mark group that needs to be read using an RF signal is formed on the guide layer 12, not only the signal level of the push-pull signal (in other words, signal characteristics) but also the signal level of the RF signal (signal (Characteristics) must also be considered.
　しかるに、本実施例では、ガイド層１２上には、元々トラッキング制御に用いられるプッシュプル信号を用いて読み取ることができる情報用マーク群ＭＧ１及び判別用マーク群ＭＧ２が記録される。従って、プッシュプル信号の信号レベル（言い換えれば、信号特性）が考慮されれば足りる。言い換えれば、ＲＦ信号の信号レベル（信号特性）が考慮されなくともよくなる。 However, in this embodiment, the information mark group MG1 and the discrimination mark group MG2 that can be read using a push-pull signal originally used for tracking control are recorded on the guide layer 12. Therefore, it is only necessary to consider the signal level (in other words, signal characteristics) of the push-pull signal. In other words, the signal level (signal characteristics) of the RF signal need not be considered.
　このため、本実施例では、グルーブトラックＧＴの深さ（更には、情報用記録マークＭＬ１、ＭＲ１及びＭＣ１、並びに判別用記録マークＭＬ２及びＭＲ２の深さ）は、λ／６ｎ未満に設定されてもよい。これにより、プッシュプル信号の信号特性が好適な特性となるため、トラッキング制御が好適に行われると共に情報用マーク群ＭＧ１及び判別用マーク群ＭＧ２が好適に読み取られる。 Therefore, in this embodiment, the depth of the groove track GT (and the depths of the information recording marks ML1, MR1 and MC1, and the recording marks ML2 and MR2 for determination) is set to be less than λ / 6n. Also good. Thereby, since the signal characteristic of the push-pull signal becomes a suitable characteristic, tracking control is suitably performed and the information mark group MG1 and the discrimination mark group MG2 are preferably read.
　或いは、グルーブトラックＧＴの深さ（更には、情報用記録マークＭＬ１、ＭＲ１及びＭＣ１、並びに判別用記録マークＭＬ２及びＭＲ２の深さ）は、λ／８ｎ未満に設定されてもよい。これにより、プッシュプル信号の信号特性が最良となるため、トラッキング制御がより一層好適に行われると共に情報用マーク群ＭＧ１及び判別用マーク群ＭＧ２がより一層好適に読み取られる。 Alternatively, the depth of the groove track GT (further, the depth of the information recording marks ML1, MR1, and MC1, and the determination recording marks ML2 and MR2) may be set to less than λ / 8n. As a result, the signal characteristics of the push-pull signal are optimized, so that tracking control is performed more suitably, and the information mark group MG1 and the discrimination mark group MG2 are more suitably read.
　加えて、本実施例では、複数のグルーブトラックＧＴの夫々の同一の回転位相位置に同一の情報用マーク群ＭＧ１が形成される。同様に、本実施例では、複数のランドトラックＬＴの夫々の同一の回転位相位置に同一の情報用マーク群ＭＧ１が形成される。このため、ガイドレーザ光ＬＢ１のフォーカス偏差（フォーカスオフセット）に対する依存性を弱める（具体的には、フォーカス偏差が大きくなった場合であっても、情報用マーク群ＭＧ１が示すプリフォーマット情報を好適に読み取る）ことができる。以下、図１７から図１９を参照して、フォーカス偏差に対する依存性を弱める効果を説明する。図１７は、単一のグルーブトラックＧＴ上に情報用マーク群ＭＧ１が形成される比較例を示す平面図である。図１８は、フォーカス偏差とプッシュプル信号の振幅との間の関係を示すグラフである。図１９（ａ）から図１９（ｃ）は、ガイド層１２でのガイドレーザ光ＬＢ１のビームスポットとグルーブトラックＧＴ並びに一対の情報用記録マークＭＬ１及びＭＲ１との位置関係を示す平面図である。 In addition, in this embodiment, the same information mark group MG1 is formed at the same rotational phase position of each of the plurality of groove tracks GT. Similarly, in this embodiment, the same information mark group MG1 is formed at the same rotational phase position of each of the plurality of land tracks LT. Therefore, the dependence of the guide laser beam LB1 on the focus deviation (focus offset) is weakened (specifically, the preformat information indicated by the information mark group MG1 is preferably used even when the focus deviation increases). Read). Hereinafter, with reference to FIG. 17 to FIG. 19, the effect of reducing the dependency on the focus deviation will be described. FIG. 17 is a plan view showing a comparative example in which the information mark group MG1 is formed on a single groove track GT. FIG. 18 is a graph showing the relationship between the focus deviation and the amplitude of the push-pull signal. FIGS. 19A to 19C are plan views showing the positional relationship between the beam spot of the guide laser beam LB1 on the guide layer 12, the groove track GT, and the pair of information recording marks ML1 and MR1.
　図１７に示すように、単一のグルーブトラックＧＴ上に情報用マーク群ＭＧ１が形成されるとする。このとき、情報用マーク群ＭＧ１を構成する一対の情報用記録マークＭＬ１及びＭＲ１のトラック中心からのシフト量を、１００ｎｍ、２２０ｎｍ、３２０ｎｍ及び６４０ｎｍの４種類に設定したときのプッシュプル信号の振幅は、図１８に示すようになる。図１８に示すように、単一のグルーブトラックＧＴ上に情報用マーク群ＭＧ１が形成される比較例では、フォーカス偏差が大きくなる（例えば、図１８では、負の方向に大きくなる）につれて、プッシュプル信号の振幅が小さくなっているのが分かる。その結果、トラッキング制御が好適に行われないばかりか、情報用マーク群ＭＧ１を用いてガイド層１２に記録されたプリフォーマット情報が好適に読み取られなくなってしまうおそれがある。これは、フォーカス偏差が大きくなるにつれてデフォーカスの度合いが強くなると、ただ一つの情報用マーク群ＭＧ１を好適に読み取ることができないことが理由であると想定される。 Suppose that the information mark group MG1 is formed on a single groove track GT as shown in FIG. At this time, the amplitude of the push-pull signal when the shift amounts from the track center of the pair of information recording marks ML1 and MR1 constituting the information mark group MG1 are set to four types of 100 nm, 220 nm, 320 nm, and 640 nm are as follows. As shown in FIG. As shown in FIG. 18, in the comparative example in which the information mark group MG1 is formed on a single groove track GT, as the focus deviation increases (for example, in the negative direction in FIG. 18, the push increases). It can be seen that the amplitude of the pull signal is small. As a result, not only tracking control is not suitably performed, but preformat information recorded on the guide layer 12 using the information mark group MG1 may not be suitably read. It is assumed that this is because if the degree of defocus increases as the focus deviation increases, only one information mark group MG1 cannot be suitably read.
　一方で、本実施例によれば、複数のグルーブトラックＧＴ（或いは、複数のランドトラックＬＴ）の夫々の同一の回転位相位置に同一の情報用マーク群ＭＧ１が形成されるため、プッシュプル信号の振幅は、トラッキングサーボをオープンにした状態で得られるプッシュプル信号の振幅と概ね同様になる。つまり、本実施例のプッシュプル信号の振幅のフォーカス偏差に対する依存性は、トラッキングサーボをオープンにした状態で得られるプッシュプル信号の振幅のフォーカス偏差に対する依存性と概ね同様になる。その結果、本実施例では、トラッキング制御が好適に行われると共に、情報用マーク群ＭＧ１を用いてガイド層１２に記録されたプリフォーマット情報が好適に読み取られる。 On the other hand, according to the present embodiment, the same information mark group MG1 is formed at the same rotational phase position of each of the plurality of groove tracks GT (or the plurality of land tracks LT). The amplitude is substantially the same as the amplitude of the push-pull signal obtained with the tracking servo open. That is, the dependency of the push-pull signal on the focus deviation in this embodiment is substantially the same as the dependency of the push-pull signal amplitude on the focus deviation obtained with the tracking servo open. As a result, in this embodiment, tracking control is suitably performed, and preformat information recorded on the guide layer 12 is suitably read using the information mark group MG1.
　というのも、トラック中心に対して右側にシフトした情報用記録マークＭＲ１をトレースしている時のガイドレーザ光ＬＢ１のビームスポットの状態（図１９（ａ）の状態Ａ１参照）は、トラッキングサーボをオープンにした状態でトラック中心から左側にずれている（位相にして、約２７０°ずれている）ガイドレーザ光ＬＢ１のビームスポットの状態（図１９（ｂ）の状態Ｂ１参照）と概ね同様である。同様に、トラック中心に対して左側にシフトした情報用記録マークＭＲ１をトレースしているときのガイドレーザ光ＬＢ１のビームスポットの状態（図１９（ａ）の状態Ａ２参照）は、トラッキングサーボをオープンにした状態でトラック中心から右側にずれている（位相にして、約９０°ずれている）ガイドレーザ光ＬＢ１のビームスポットの状態（図１９（ｂ）の状態Ｂ２参照）と概ね同様である。従って、図１９（ａ）に示す状態のガイドレーザ光ＬＢ１から得られるプッシュプル信号の波形は、図１９（ｂ）に示す状態のガイドレーザ光ＬＢ１から得られるプッシュプル信号の波形と概ね同様になる（図１９（ｃ）参照）。このため、上述したように、本実施例のプッシュプル信号の振幅のフォーカス偏差に対する依存性は、トラッキングサーボをオープンにした状態で得られるプッシュプル信号の振幅のフォーカス偏差に対する依存性と概ね同様になる。 This is because the state of the beam spot of the guide laser beam LB1 (see the state A1 in FIG. 19A) when the information recording mark MR1 shifted to the right with respect to the track center is being traced is determined by the tracking servo. It is substantially the same as the state of the beam spot of the guide laser beam LB1 (see state B1 in FIG. 19B) shifted to the left side from the track center in the open state (shifted by about 270 ° in phase). . Similarly, the tracking servo is opened in the state of the beam spot of the guide laser beam LB1 (see the state A2 in FIG. 19A) when tracing the information recording mark MR1 shifted to the left with respect to the track center. In this state, it is substantially the same as the state of the beam spot of the guide laser beam LB1 (referred to as state B2 in FIG. 19B) shifted to the right side from the track center (shifted by about 90 ° in phase). Accordingly, the waveform of the push-pull signal obtained from the guide laser beam LB1 in the state shown in FIG. 19A is almost the same as the waveform of the push-pull signal obtained from the guide laser beam LB1 in the state shown in FIG. (See FIG. 19C). For this reason, as described above, the dependency of the amplitude of the push-pull signal on the focus deviation in this embodiment is almost the same as the dependency of the amplitude of the push-pull signal obtained with the tracking servo open on the focus deviation. Become.
　尚、上述した先行技術３及び６から１１に開示された技術は、いずれも図１７に示すような単一の記録トラック上に単一のデータを記録するために単一の記録トラック上に形成される記録ピットないしはウォブルを左右にシフトさせているに過ぎない。つまり、上述した先行技術３及び６から１１に開示された技術は、複数の記録トラックの同一の回転位相位置に同一のデータを記録していない（言い換えれば、同一のデータを示すピットないしはウォブルを形成していない）という点で本実施例とは異なっている。 The techniques disclosed in the prior arts 3 and 6 to 11 described above are all formed on a single recording track in order to record a single data on a single recording track as shown in FIG. It just shifts the recorded pit or wobble to the left or right. In other words, the techniques disclosed in the above-described prior arts 3 and 6 to 11 do not record the same data at the same rotational phase position of a plurality of recording tracks (in other words, pits or wobbles indicating the same data are not recorded). This is different from the present embodiment in that it is not formed.
　加えて、本実施例では、判別用記録マークＭＬ２及び判別用記録マークＭＲ２の夫々の幅は、ガイドトラックＴＲの幅の２倍以上である。このため、判別用マーク群ＭＧ２においても、情報用マーク群ＭＧ１と同様に、ガイドレーザ光ＬＢ１のフォーカス偏差（フォーカスオフセット）に対する依存性を弱める（具体的には、フォーカス偏差が大きくなった場合であっても、判別用マーク群ＭＧ２を好適に読み取る）ことができる。 In addition, in this embodiment, the width of each of the discrimination recording mark ML2 and the discrimination recording mark MR2 is twice or more the width of the guide track TR. For this reason, in the discrimination mark group MG2 as well as the information mark group MG1, the dependency of the guide laser beam LB1 on the focus deviation (focus offset) is weakened (specifically, when the focus deviation increases). Even in such a case, the discrimination mark group MG2 can be read suitably).
　尚、上述した先行技術２から５に開示された技術は、いずれも記録トラックの幅と同一の幅を有する記録ピットを形成しているに過ぎない。つまり、上述した先行技術２から５に開示された技術は、記録トラックの幅の２倍以上の幅を有する記録ピットを形成していないという点で本実施例とは異なっている。 Note that all of the techniques disclosed in the prior arts 2 to 5 described above merely form recording pits having the same width as the width of the recording track. That is, the techniques disclosed in the prior arts 2 to 5 described above are different from the present embodiment in that no recording pits having a width twice or more the width of the recording track are formed.
　加えて、本実施例によれば、グルーブトラックＧＴ及びランドトラックＬＴの双方に情報用マーク群ＭＧ１が形成される。このため、グルーブトラックＧＴ及びランドトラックＬＴの一方のみに情報用マーク群ＭＧ１が形成される光ディスクと比較して、ガイド層１２に記録可能なプリフォーマット情報のサイズを増大させることができる。更に、このため、グルーブトラックＧＴ及びランドトラックＬＴの一方のみに情報用マーク群ＭＧ１が形成される光ディスクと比較して、ガイド層１２に記録されたプリフォーマット情報が読み取りやすくなる。 In addition, according to the present embodiment, the information mark group MG1 is formed on both the groove track GT and the land track LT. Therefore, the size of the preformat information that can be recorded on the guide layer 12 can be increased as compared with the optical disc in which the information mark group MG1 is formed only on one of the groove track GT and the land track LT. Furthermore, this makes it easier to read the preformat information recorded on the guide layer 12 as compared with an optical disc in which the information mark group MG1 is formed on only one of the groove track GT and the land track LT.
　加えて、本実施例によれば、グルーブトラックＧＴ及びランドトラックＬＴの双方に判別用マーク群ＭＧ２が形成される。このため、グルーブトラックＧＴ及びランドトラックＬＴの一方のみに判別用マーク群ＭＧ２が形成される光ディスクと比較して、グルーブトラックＧＴ及びランドトラックＬＴの双方を対象としてセンタートラックＣＴであるか否かの判別が行われる。このためグルーブトラックＧＴ及びランドトラックＬＴの双方に情報用マーク群ＭＧ１が形成される場合であっても、当該情報用マーク群ＭＧ１が好適に読み取られる。 In addition, according to the present embodiment, the discrimination mark group MG2 is formed on both the groove track GT and the land track LT. For this reason, it is determined whether or not the center track CT is for both the groove track GT and the land track LT as compared with the optical disc in which the discrimination mark group MG2 is formed only on one of the groove track GT and the land track LT. A determination is made. Therefore, even when the information mark group MG1 is formed on both the groove track GT and the land track LT, the information mark group MG1 is preferably read.
　加えて、本実施例によれば、同期データを構成する情報用マーク群ＭＧ１には、一対の情報用記録マークＭＬ１及びＭＲ１に加えて、トラック中心上に位置する情報用記録マークＭＣ１が含まれる。このため、プッシュプル信号の信号レベルの基準値（例えば、ゼロレベル）が変動してしまう場合であっても、一対の情報用記録マークＭＬ１及びＭＲ１に応じたプッシュプル信号の信号レベルの変動を好適に認識することができる。以下、図２０を参照しながら、プッシュプル信号の信号レベルの基準値が変動してしまう場合であっても、一対の情報用記録マークＭＬ１及びＭＲ１に応じたプッシュプル信号の信号レベルの変動を好適に認識することができる利点について説明する。図２０は、一対の情報用記録マークＭＬ１及びＭＲ１並びにトラック中心上に位置する情報用記録マークＭＣ１が含まれる同期データを構成する情報用マーク群ＭＧ１から得られるプッシュプル信号を示すグラフである。 In addition, according to the present embodiment, the information mark group MG1 constituting the synchronization data includes the information recording mark MC1 located on the track center in addition to the pair of information recording marks ML1 and MR1. . For this reason, even if the reference value (for example, zero level) of the signal level of the push-pull signal varies, the signal level of the push-pull signal varies according to the pair of information recording marks ML1 and MR1. It can be suitably recognized. Hereinafter, referring to FIG. 20, even if the reference value of the signal level of the push-pull signal varies, the signal level of the push-pull signal corresponding to the pair of information recording marks ML1 and MR1 is varied. The advantages that can be suitably recognized will be described. FIG. 20 is a graph showing a push-pull signal obtained from the information mark group MG1 constituting the synchronization data including the pair of information recording marks ML1 and MR1 and the information recording mark MC1 located on the track center.
　図２０（ａ）に示すように、プッシュプル信号の信号レベルの基準値が変動しない場合には、いわゆるデフォールトのゼロレベルを用いて、一対の情報用記録マークＭＬ１及びＭＲ１に応じたプッシュプル信号の信号レベルの変動が好適に認識される。 As shown in FIG. 20A, when the reference value of the signal level of the push-pull signal does not fluctuate, the push-pull signal corresponding to the pair of information recording marks ML1 and MR1 is used by using a so-called default zero level. Signal level fluctuations are preferably recognized.
　一方で、図２０（ｂ）の左側の実線で示すように、プッシュプル信号の信号レベルの基準値が変動してしまう（例えば、正方向にシフトしてしまう）場合には、いわゆるデフォールトのゼロレベルを用いると、情報用記録マークＭＬ１に応じたプッシュプル信号の信号レベルと情報用記録マークＭＲ１に応じたプッシュプル信号の信号レベルとが互いに異なるものとなってしまう。その結果、プッシュプル信号に基づく情報用記録マークＭＬ１及びＭＲ１の読み取りの信頼性が悪化してしまいかねない。 On the other hand, as shown by the solid line on the left side of FIG. 20B, when the reference value of the signal level of the push-pull signal changes (for example, shifts in the positive direction), the so-called default zero is obtained. When the level is used, the signal level of the push-pull signal corresponding to the information recording mark ML1 and the signal level of the push-pull signal corresponding to the information recording mark MR1 are different from each other. As a result, the reliability of reading the information recording marks ML1 and MR1 based on the push-pull signal may deteriorate.
　しかるに、本実施例では、図２０（ｂ）の右側の点線で示すように、トラック中心上に位置する情報用記録マークＭＣ１に応じたプッシュプル信号の信号レベルを用いて、プッシュプル信号の信号レベルの基準値を調整することができる。従って、プッシュプル信号の信号レベルの基準値（例えば、ゼロレベル）が変動してしまう場合であっても、一対の情報用記録マークＭＬ１及びＭＲ１に応じたプッシュプル信号の信号レベルの変動を好適に認識することができる。 However, in this embodiment, as shown by the dotted line on the right side of FIG. 20B, the signal of the push-pull signal is used by using the signal level of the push-pull signal corresponding to the information recording mark MC1 located on the track center. The level reference value can be adjusted. Therefore, even if the reference value (for example, zero level) of the signal level of the push-pull signal varies, it is preferable to vary the signal level of the push-pull signal according to the pair of information recording marks ML1 and MR1. Can be recognized.
　（３）変形例
　続いて、図２１から図２８を参照して、本実施例の光ディスク１１の変形例について説明する。尚、以下は、いずれも、判別用マーク群ＭＧ２の変形例に相当する。 (3) Modified Example Next, with reference to FIGS. 21 to 28, a modified example of the optical disc 11 of the present embodiment will be described. The followings correspond to modifications of the discrimination mark group MG2.
　（３－１）第１変形例
　はじめに、図２１及び図２２を参照して、第１変形例について説明する。図２１は、第１変形例の判別用マーク群ＭＧ２が形成されたグルーブトラックＧＴ上をトレースするガイドレーザ光ＬＢ１の戻り光から得られるプッシュプル信号の信号レベルを、グルーブトラックＧＴに形成される第１変形例の判別用マーク群ＭＧ２の構成と対応付けて示すグラフである。図２２は、図２１に示す第１変形例の判別用マーク群ＭＧ２を用いてセンタートラックＣＴを判別する動作を示すフローチャートである。 (3-1) First Modification First, a first modification will be described with reference to FIGS. 21 and 22. In FIG. 21, the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 tracing on the groove track GT on which the discrimination mark group MG2 of the first modification is formed is formed on the groove track GT. It is a graph shown in association with the configuration of the discrimination mark group MG2 of the first modification. FIG. 22 is a flowchart showing an operation of discriminating the center track CT using the discrimination mark group MG2 of the first modification shown in FIG.
　図２１に示すように、第１変形例では、グルーブトラックＧＴに形成される判別用マーク群ＭＧ２は、異なる回転位相位置に形成される一対の判別用記録マークＭＬ２及びＭＲ２をただ一つだけ含んでいる一方で、同一の回転位相位置に形成される一対の判別用記録マークＭＬ２及びＭＲ２を含んでいない。つまり、第１変形例では、判別用マーク群ＭＧ２は、上述した判別用マーク群ＭＧ２（図７及び図８参照）と比較して、第１マーク区間に対応する判別用記録マークＭＬ２（＃１）及び第３マーク区間に対応する判別用記録マークＭＲ２（＃１）を含んでいる一方で、第２マーク区間に対応する一対の判別用記録マークＭＬ２（＃２）及びＭＲ２（＃２）を含んでいないという点で異なっている。 As shown in FIG. 21, in the first modification, the discrimination mark group MG2 formed on the groove track GT includes only one pair of discrimination recording marks ML2 and MR2 formed at different rotational phase positions. On the other hand, it does not include the pair of discrimination recording marks ML2 and MR2 formed at the same rotational phase position. That is, in the first modification, the discrimination mark group MG2 is compared with the discrimination mark group MG2 (see FIGS. 7 and 8) described above, and the discrimination recording mark ML2 (# 1) corresponding to the first mark section. ) And the third mark section, and a pair of determination recording marks ML2 (# 2) and MR2 (# 2) corresponding to the second mark section. It differs in that it does not contain.
　第１変形例では、図２１の１番目のグラフに示すように、トラック番号が「ｋ－２」となるグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「＋区間」であり且つ第３マーク区間が「０区間」であることを示している。 In the first modification, as shown in the first graph of FIG. 21, the signal of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k-2”. The level indicates that the first mark section is “+ section” and the third mark section is “0 section”.
　同様に、図２１の２番目のグラフに示すように、トラック番号が「ｋ」となるグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「－区間」であり且つ第３マーク区間が「＋区間」であることを示している。 Similarly, as shown in the second graph of FIG. 21, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k” is the first level. The mark section is “−section” and the third mark section is “+ section”.
　同様に、図２１の３番目のグラフに示すように、トラック番号が「ｋ＋２」となるグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「０区間」であり且つ第３マーク区間が「－区間」であることを示している。 Similarly, as shown in the third graph of FIG. 21, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k + 2” is the first level. The mark section is “0 section” and the third mark section is “−section”.
　この場合、ガイドレーザ光ＬＢ１がトレースしているグルーブトラックＧＴがセンタートラックＣＴであるか否かを判別するために、図２２に示すように、まず、第１マーク区間が「－区間」であるか否かが判定される（ステップＳ１１）。 In this case, in order to determine whether or not the groove track GT traced by the guide laser beam LB1 is the center track CT, first, as shown in FIG. 22, the first mark section is a “−section”. It is determined whether or not (step S11).
　ステップＳ１１の判定の結果、第１マーク区間が「－区間」であると判定される場合には（ステップＳ１１：Ｙｅｓ）、続いて、第３マーク区間が「＋区間」であるか否かが判定される（ステップＳ１２）。 As a result of the determination in step S11, if it is determined that the first mark section is “−section” (step S11: Yes), then whether or not the third mark section is “+ section” is determined. Determination is made (step S12).
　ステップＳ１２の判定の結果、第３マーク区間が「＋区間」であると判定される場合には（ステップＳ１２：Ｙｅｓ）、ガイドレーザ光ＬＢ１が現在トレースしているグルーブトラックＧＴがセンタートラックＣＴであると判別される（ステップＳ１３）。 As a result of the determination in step S12, when it is determined that the third mark section is “+ section” (step S12: Yes), the groove track GT currently being traced by the guide laser beam LB1 is the center track CT. It is determined that there is (step S13).
　他方で、ステップＳ１２の判定の結果、第３マーク区間が「＋区間」でないと判定される場合には（ステップＳ１２：Ｎｏ）、ガイドレーザ光ＬＢ１が現在トレースしているグルーブトラックＧＴがセンタートラックＣＴでないと判別される（ステップＳ１７）。 On the other hand, if it is determined in step S12 that the third mark section is not the “+ section” (step S12: No), the groove track GT currently being traced by the guide laser beam LB1 is the center track. It is determined that it is not CT (step S17).
　他方で、ステップＳ１１の判定の結果、第１マーク区間が「－区間」でないと判定される場合には（ステップＳ１１：Ｎｏ）、ガイドレーザ光ＬＢ１が現在トレースしているグルーブトラックＧＴがセンタートラックＣＴでないと判別される（ステップＳ１７）。 On the other hand, as a result of the determination in step S11, if it is determined that the first mark section is not the “− section” (step S11: No), the groove track GT currently being traced by the guide laser beam LB1 is the center track. It is determined that it is not CT (step S17).
　図２２に示す動作を図２１に示す判別用マーク群ＭＧ２に具体的に適用した場合の例について、以下に説明する。 An example in which the operation shown in FIG. 22 is specifically applied to the discrimination mark group MG2 shown in FIG. 21 will be described below.
　トラック番号が「ｋ－２」となるグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「＋区間」であり且つ第３マーク区間が「０区間」であることを示している。従って、この場合には、第１マーク区間が－区間でない（ステップＳ１１：Ｎｏ）と判定される。従って、ガイドレーザ光ＬＢ１が現在トレースしているグルーブトラックＧＴ（つまり、トラック番号が「ｋ－２」となるグルーブトラックＧＴ）がセンタートラックＣＴでないと判別される（ステップＳ１７）。 The signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k-2” is the “+ interval” in the first mark interval and the third mark This indicates that the section is “0 section”. Therefore, in this case, it is determined that the first mark section is not the − section (step S11: No). Accordingly, it is determined that the groove track GT currently traced by the guide laser beam LB1 (that is, the groove track GT with the track number “k−2”) is not the center track CT (step S17).
　続いて、トラック番号が「ｋ」となるグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「－区間」であり且つ第３マーク区間が「＋区間」であることを示している。従って、この場合には、第１マーク区間が－区間である（ステップＳ１１：Ｙｅｓ）と判定され且つ第３マーク区間が＋区間である（ステップＳ１２：Ｙｅｓ）と判定される。従って、ガイドレーザ光ＬＢ１が現在トレースしているグルーブトラックＧＴ（つまり、トラック番号が「ｋ」となるグルーブトラックＧＴ）がセンタートラックＣＴであると判別される（ステップＳ１３）。 Subsequently, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k” is the “−section” in the first mark section and the third level. It indicates that the mark section is “+ section”. Therefore, in this case, it is determined that the first mark section is the-section (step S11: Yes) and the third mark section is the + section (step S12: Yes). Therefore, it is determined that the groove track GT currently traced by the guide laser beam LB1 (that is, the groove track GT with the track number “k”) is the center track CT (step S13).
　同様に、トラック番号が「ｋ＋２」となるグルーブトラックＧＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「０区間」であり且つ第３マーク区間が「－区間」であることを示している。従って、この場合には、第１マーク区間が－区間でない（ステップＳ１１：Ｎｏ）と判定される。従って、ガイドレーザ光ＬＢ１が現在トレースしているグルーブトラックＧＴ（つまり、トラック番号が「ｋ＋２」となるグルーブトラックＧＴ）がセンタートラックＣＴでないと判別される（ステップＳ１７）。 Similarly, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the groove track GT with the track number “k + 2” is the “0 section” in the first mark section and the third level. It indicates that the marked section is “−section”. Therefore, in this case, it is determined that the first mark section is not the − section (step S11: No). Therefore, it is determined that the groove track GT currently traced by the guide laser beam LB1 (that is, the groove track GT with the track number “k + 2”) is not the center track CT (step S17).
　このように、第１変形例においても、判別用マーク群ＭＧ２を用いて、センタートラックＣＴが好適に判別される。 Thus, also in the first modification, the center track CT is suitably discriminated using the discrimination mark group MG2.
　特に、第１変形例では、一対の判別用記録マークＭＬ２及びＭＲ２のみ（つまり、ただ２つの判別用記録マークＭＬ２及びＭＲ２）を用いて、ガイドレーザ光ＬＢ１がトレースしているグルーブトラックＧＴがセンタートラックＣＴであるか否かが判別される。このため、判別用マーク群ＭＧ２が形成される領域のサイズ（例えば、グルーブトラックＧＴの進行方向に沿った長さ）を相対的に短くすることができる。 In particular, in the first modification, the groove track GT traced by the guide laser beam LB1 is centered using only a pair of determination recording marks ML2 and MR2 (that is, only two determination recording marks ML2 and MR2). It is determined whether or not the track CT. For this reason, the size (for example, the length along the traveling direction of the groove track GT) of the region where the discrimination mark group MG2 is formed can be relatively shortened.
　加えて、第１変形例では、５つのガイドトラックＴＲ（つまり、トラック番号がｋ－２となるガイドトラックＴＲからトラック番号がｋ＋２となるガイドトラックＴＲ）に収まるように判別用マーク群ＭＧ２を形成することができる。このため、異なるガイドトラックＴＲの同一の回転位相位置に異なる判別用マーク群ＭＧを形成する場合において、異なる判別用マーク群ＭＧの間の間隔を相対的に狭くすることができる。 In addition, in the first modified example, the determination mark group MG2 is formed so as to fit on the five guide tracks TR (that is, from the guide track TR with the track number k-2 to the guide track TR with the track number k + 2). can do. Therefore, when different determination mark groups MG are formed at the same rotational phase position of different guide tracks TR, the interval between the different determination mark groups MG can be relatively narrowed.
　加えて、第１変形例では、ガイドレーザ光ＬＢ１がトレースしているグルーブトラックＧＴがセンタートラックＣＴであるか否かを判別するための動作（言い換えれば、アルゴリズムであり、図２１に示す動作）が相対的に簡略化される。 In addition, in the first modification, an operation for determining whether or not the groove track GT traced by the guide laser beam LB1 is the center track CT (in other words, an algorithm, the operation shown in FIG. 21). Is relatively simplified.
　（３－２）第２変形例
　続いて、図２３及び図２４を参照して、第２変形例について説明する。図２２は、第２変形例の判別用マーク群ＭＧ２が形成されたランドトラックＬＴ上をトレースするガイドレーザ光ＬＢ１の戻り光から得られるプッシュプル信号の信号レベルを、ランドトラックＬＴに形成される第２変形例の判別用マーク群ＭＧ２の構成と対応付けて示すグラフである。図２４は、図２３に示す第２変形例の判別用マーク群ＭＧ２を用いてセンタートラックＣＴを判別する動作を示すフローチャートである。 (3-2) Second Modification Next, a second modification will be described with reference to FIGS. 23 and 24. FIG. In FIG. 22, the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 tracing on the land track LT on which the discrimination mark group MG2 of the second modification is formed is formed on the land track LT. It is a graph shown in association with the configuration of the discrimination mark group MG2 of the second modification. FIG. 24 is a flowchart showing an operation of discriminating the center track CT using the discrimination mark group MG2 of the second modification shown in FIG.
　図２３に示すように、第２変形例では、ランドトラックＬＴに形成される判別用マーク群ＭＧ２は、異なる回転位相位置に形成される一対の判別用記録マークＭＬ２及びＭＲ２をただ一つだけ含んでいる一方で、同一の回転位相位置に形成される一対の判別用記録マークＭＬ２及びＭＲ２を含んでいない。つまり、第２変形例では、判別用マーク群ＭＧ２は、上述した判別用マーク群ＭＧ２（図１０及び図１１参照）と比較して、第１マーク区間に対応する判別用記録マークＭＬ２（＃１）及び第３マーク区間に対応する判別用記録マークＭＲ２（＃１）を含んでいる一方で、第２マーク区間に対応する一対の判別用記録マークＭＬ２（＃２）及びＭＲ２（＃２）を含んでいないという点で異なっている。 As shown in FIG. 23, in the second modification, the discrimination mark group MG2 formed on the land track LT includes only one pair of discrimination recording marks ML2 and MR2 formed at different rotational phase positions. On the other hand, it does not include the pair of discrimination recording marks ML2 and MR2 formed at the same rotational phase position. That is, in the second modification, the discrimination mark group MG2 is compared with the discrimination mark group MG2 (see FIGS. 10 and 11) described above, and the discrimination recording mark ML2 (# 1) corresponding to the first mark section. ) And the third mark section, and a pair of determination recording marks ML2 (# 2) and MR2 (# 2) corresponding to the second mark section. It differs in that it does not contain.
　第２変形例では、図２３の１番目のグラフに示すように、トラック番号が「ｋ－１」となるランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「＋区間」であり、且つ第３マーク区間が「０区間」であることを示している。 In the second modification, as shown in the first graph of FIG. 23, the signal of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k−1”. The level indicates that the first mark section is “+ section” and the third mark section is “0 section”.
　同様に、図２３の２番目のグラフに示すように、トラック番号が「ｋ＋１」となるランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「－区間」であり且つ第３マーク区間が「＋区間」であることを示している。 Similarly, as shown in the second graph of FIG. 23, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 1” is the first level. The mark section is “−section” and the third mark section is “+ section”.
　同様に、図２３の３番目のグラフに示すように、トラック番号が「ｋ＋３」となるランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「０区間」であり且つ第３マーク区間が「－区間」であることを示している。 Similarly, as shown in the third graph of FIG. 23, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 3” is the first level. The mark section is “0 section” and the third mark section is “−section”.
　この場合、ガイドレーザ光ＬＢ１がトレースしているランドトラックＬＴがセンタートラックＣＴであるか否かを判別するために、図２３に示すように、まず、第１マーク区間が「－区間」であるか否かが判定される（ステップＳ２１）。 In this case, in order to determine whether or not the land track LT traced by the guide laser beam LB1 is the center track CT, first, as shown in FIG. 23, the first mark section is a “−section”. Is determined (step S21).
　ステップＳ２１の判定の結果、第１マーク区間が「－区間」であると判定される場合には（ステップＳ２１：Ｙｅｓ）、続いて、第３マーク区間が「＋区間」であるか否かが判定される（ステップＳ２２）。 As a result of the determination in step S21, when it is determined that the first mark section is “−section” (step S21: Yes), it is subsequently determined whether the third mark section is “+ section” or not. Determination is made (step S22).
　ステップＳ２２の判定の結果、第３マーク区間が「＋区間」であると判定される場合には（ステップＳ２２：Ｙｅｓ）、ガイドレーザ光ＬＢ１が現在トレースしているランドトラックＬＴがセンタートラックＣＴであると判別される（ステップＳ２３）。 As a result of the determination in step S22, when it is determined that the third mark section is “+ section” (step S22: Yes), the land track LT currently traced by the guide laser beam LB1 is the center track CT. It is determined that there is (step S23).
　他方で、ステップＳ２２の判定の結果、第３マーク区間が「＋区間」でないと判定される場合には（ステップＳ２２：Ｎｏ）、ガイドレーザ光ＬＢ１が現在トレースしているランドトラックＬＴがセンタートラックＣＴでないと判別される（ステップＳ２７）。 On the other hand, if it is determined in step S22 that the third mark section is not the “+ section” (step S22: No), the land track LT currently being traced by the guide laser beam LB1 is the center track. It is determined that it is not CT (step S27).
　他方で、ステップＳ２１の判定の結果、第１マーク区間が「－区間」でないと判定される場合には（ステップＳ２１：Ｎｏ）、ガイドレーザ光ＬＢ１が現在トレースしているランドトラックＬＴがセンタートラックＣＴでないと判別される（ステップＳ２７）。 On the other hand, as a result of the determination in step S21, if it is determined that the first mark section is not the “− section” (step S21: No), the land track LT currently traced by the guide laser beam LB1 is the center track. It is determined that it is not CT (step S27).
　図２４に示す動作を図２２に示す判別用マーク群ＭＧ２に具体的に適用した場合の例について、以下に説明する。 An example where the operation shown in FIG. 24 is specifically applied to the discrimination mark group MG2 shown in FIG. 22 will be described below.
　トラック番号が「ｋ－１」となるランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「＋区間」であり且つ第３マーク区間が「０区間」であることを示している。従って、この場合には、第１マーク区間が－区間でない（ステップＳ２１：Ｎｏ）と判定される。従って、ガイドレーザ光ＬＢ１がトレースしているランドトラックＬＴ（つまり、トラック番号が「ｋ－１」となるランドトラックＬＴ）がセンタートラックＣＴでないと判別される（ステップＳ２７）。 The signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT whose track number is “k−1” is the first mark section is “+ section” and the third mark This indicates that the section is “0 section”. Therefore, in this case, it is determined that the first mark section is not the − section (step S21: No). Accordingly, it is determined that the land track LT traced by the guide laser beam LB1 (that is, the land track LT with the track number “k−1”) is not the center track CT (step S27).
　続いて、トラック番号が「ｋ＋１」となるランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「－区間」であり且つ第３マーク区間が「＋区間」であることを示している。従って、この場合には、第１マーク区間が－区間である（ステップＳ２１：Ｙｅｓ）と判定され且つ第３マーク区間が＋区間である（ステップＳ２２：Ｙｅｓ）と判定される。従って、ガイドレーザ光ＬＢ１がトレースしているランドトラックＬＴ（つまり、トラック番号が「ｋ＋１」となるランドトラックＬＴ）がセンタートラックＣＴであると判別される（ステップＳ２３）。 Subsequently, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 1” is the “−section” in the first mark section and the third level. It indicates that the mark section is “+ section”. Therefore, in this case, it is determined that the first mark section is the-section (step S21: Yes) and the third mark section is the + section (step S22: Yes). Accordingly, it is determined that the land track LT traced by the guide laser beam LB1 (that is, the land track LT with the track number “k + 1”) is the center track CT (step S23).
　同様に、トラック番号が「ｋ＋３」となるランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、第１マーク区間が「０区間」であり且つ第３マーク区間が「－区間」であることを示している。従って、この場合には、第１マーク区間が－区間でない（ステップＳ２１：Ｎｏ）と判定される。従って、ガイドレーザ光ＬＢ１がトレースしているランドトラックＬＴ（つまり、トラック番号が「ｋ＋３」となるランドトラックＬＴ）がセンタートラックＣＴでないと判別される（ステップＳ２７）。 Similarly, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 3” is “0 section” in the first mark section and the third level. It indicates that the marked section is “−section”. Therefore, in this case, it is determined that the first mark section is not the − section (step S21: No). Accordingly, it is determined that the land track LT traced by the guide laser beam LB1 (that is, the land track LT with the track number “k + 3”) is not the center track CT (step S27).
　このように、第２変形例においても、判別用マーク群ＭＧ２を用いて、センタートラックＣＴが好適に判別される。加えて、第２変形例においても、第１変形例において享受することができる各種効果を好適に享受することができる。 As described above, also in the second modification, the center track CT is suitably discriminated using the discrimination mark group MG2. In addition, also in the 2nd modification, the various effects which can be enjoyed in the 1st modification can be enjoyed suitably.
　（３－３）第３変形例
　続いて、図２５及び図２６を参照して、第３変形例について説明する。図２５は、第３変形例の判別用マーク群ＭＧ２が形成されたランドトラックＬＴ上をトレースするガイドレーザ光ＬＢ１の戻り光から得られるプッシュプル信号の信号レベルを、ランドトラックＬＴに形成される第３変形例の判別用マーク群ＭＧ２の構成と対応付けて示すグラフである。図２６は、図２５に示す第３変形例の判別用マーク群ＭＧ２を用いてセンタートラックＣＴを判別する動作を示すフローチャートである。 (3-3) Third Modification Next, a third modification will be described with reference to FIGS. 25 and 26. In FIG. 25, the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 tracing on the land track LT on which the discrimination mark group MG2 of the third modification is formed is formed on the land track LT. It is a graph shown in association with the configuration of the discrimination mark group MG2 of the third modification. FIG. 26 is a flowchart showing an operation of discriminating the center track CT using the discrimination mark group MG2 of the third modification shown in FIG.
　図２５に示すように、第３変形例では、ランドトラックＬＴに形成される判別用マーク群ＭＧ２は、異なる回転位相位置に形成される一対の判別用記録マークＭＬ２及びＭＲ２を複数含んでいる。具体的には、判別用マーク群ＭＧ２は、異なる回転位相位置に形成される一対の判別用記録マークＭＬ２（＃１）及びＭＲ２（＃１）と、異なる回転位相位置に形成される一対の判別用記録マークＭＬ２（＃２）及びＭＲ２（＃２）とを含んでいる。但し、判別用マーク群ＭＧ２は、同一の回転位相位置に形成される一対の判別用記録マークＭＬ２及びＭＲ２を含んでいてもよい。 As shown in FIG. 25, in the third modification, the discrimination mark group MG2 formed on the land track LT includes a plurality of a pair of discrimination recording marks ML2 and MR2 formed at different rotational phase positions. Specifically, the discrimination mark group MG2 includes a pair of discrimination recording marks ML2 (# 1) and MR2 (# 1) formed at different rotational phase positions and a pair of discrimination formed at different rotational phase positions. Recording marks ML2 (# 2) and MR2 (# 2). However, the discrimination mark group MG2 may include a pair of discrimination recording marks ML2 and MR2 formed at the same rotational phase position.
　特に、第３変形例では、各ランドトラックＬＴをトレースする場合に２つ以上のマーク区間において「０区間」、「＋区間」又は「－区間」であると判定されるように、一対の判別用記録マークＭＬ２及びＭＲ２が形成される。言い換えれば、各ランドトラックＬＴをトレースする場合に２つ以上のマーク区間において「隣接でない区間」、「＋不定区間」又は「－不定区間」であると判定されないように、一対の判別用記録マークＭＬ２及びＭＲ２が形成される。 In particular, in the third modified example, when each land track LT is traced, a pair of determinations are made so that it is determined as “0 section”, “+ section”, or “− section” in two or more mark sections. Recording marks ML2 and MR2 are formed. In other words, when tracing each land track LT, a pair of discriminating recording marks is used so that the two or more mark sections are not determined to be “non-adjacent sections”, “+ undefined sections” or “−undefined sections”. ML2 and MR2 are formed.
　尚、判別用記録マークＭＬ２及びＭＲ２がビームスポットに包含されないマーク区間は、「０区間」であると確実に判定されるものと取り扱ってもよい。また、ガイドトラックＴＲの幅の３倍以上となる幅を有する判別用記録マークＭＬ２及びＭＲ２がビームスポットに包含されるマーク区間は、「＋区間」又は「－区間」であると確実に判定されるものとして取り扱ってもよい。他方で、ガイドトラックＴＲの幅の２倍以下となる（或いは、３倍未満となる）幅を有する判別用記録マークＭＬ２及びＭＲ２がビームスポットに包含されるマーク区間は、「＋区間」若しくは「＋不定区間」又は「－区間」若しくは「－不定区間」であると判定されやすくなる。従って、２つ以上のマーク区間において「０区間」、「＋区間」又は「－区間」であると判定されるためには、各ランドトラックＬＴ上の２つ以上のマーク区間が、判別用記録マークＭＬ２及びＭＲ２がビームスポットに包含されないマーク区間又はガイドトラックＴＲの幅の３倍以上となる幅を有する判別用記録マークＭＬ２及びＭＲ２がビームスポットに包含されるマーク区間となるように、判別用マーク群ＭＧ２が形成されてもよい。 It should be noted that the mark section in which the discrimination recording marks ML2 and MR2 are not included in the beam spot may be handled as being reliably determined as “0 section”. Further, the mark section in which the discrimination recording marks ML2 and MR2 having a width that is three times or more the width of the guide track TR are included in the beam spot is reliably determined to be the “+ section” or the “− section”. It may be handled as a thing. On the other hand, the mark section in which the recording marks ML2 and MR2 for determination having a width that is less than or equal to twice (or less than three times) the width of the guide track TR are included in the beam spot is “+ section” or “ It becomes easy to determine that it is “+ undefined section”, “−section” or “−undefined section”. Accordingly, two or more mark sections on each land track LT need to be recorded for determination in order to be determined as “0 section”, “+ section”, or “− section” in two or more mark sections. For determination so that the marks ML2 and MR2 are not included in the beam spot, or the determination recording marks ML2 and MR2 having a width that is three times or more the width of the guide track TR are included in the beam spot. A mark group MG2 may be formed.
　具体的には、図２５の１番目のグラフに示すように、トラック番号が「ｋ－１」となるランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、以下のようになる。まず、第１マーク区間では、ビームスポットに判別用記録マークＭＬ２及びＭＲ２が包含されないため、当該第１マーク区間が「０区間」であると判定される。第２マーク区間では、ビームスポットにガイドトラックＴＲの幅の２倍となる幅を有する判別用記録マークＭＬ２（＃１）が包含されるため、当該第２マーク区間が「＋不定区間（但し、場合によっては＋区間）」であると判定されるおそれがある。第３マーク区間では、ビームスポットにガイドトラックＴＲの幅の３倍となる幅を有する判別用記録マークＭＲ２（＃２）の一部のみが包含される（つまり、実質的には、ビームスポットにガイドトラックＴＲの幅の２倍となる幅を有する判別用記録マークＭＲ２（＃２）が包含される）ため、当該第３マーク区間が「－不定区間」若しくは「＋不定区間」であると判定されるおそれがある。第４マーク区間では、ビームスポットにガイドトラックＴＲの幅の３倍となる幅を有する判別用記録マークＭＬ２（＃２）が包含されるため、当該第４マーク区間が「＋区間」であると判定される。従って、図２５に示す例によれば、トラック番号が「ｋ－１」となるランドトラックＬＴをトレースする場合には、第１マーク区間及び第４マーク区間において、「０区間」、「＋区間」と判定される。 Specifically, as shown in the first graph of FIG. 25, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k−1”. Is as follows. First, in the first mark section, since the recording marks ML2 and MR2 for determination are not included in the beam spot, it is determined that the first mark section is “0 section”. In the second mark section, the beam spot includes the determination recording mark ML2 (# 1) having a width that is twice the width of the guide track TR. Therefore, the second mark section is “+ indefinite section (however, In some cases, it may be determined that it is “+ section)”. In the third mark section, only a part of the determination recording mark MR2 (# 2) having a width that is three times the width of the guide track TR is included in the beam spot (that is, the beam spot is substantially included in the beam spot. Since the determination recording mark MR2 (# 2) having a width that is twice the width of the guide track TR is included), it is determined that the third mark section is “−undefined section” or “+ undefined section”. There is a risk of being. In the fourth mark section, the recording mark ML2 (# 2) for determination having a width that is three times the width of the guide track TR is included in the beam spot, so that the fourth mark section is “+ section”. Determined. Therefore, according to the example shown in FIG. 25, when the land track LT having the track number “k−1” is traced, the “0 section”, “+ section” in the first mark section and the fourth mark section. Is determined.
　同様に、図２５の２番目のグラフに示すように、トラック番号が「ｋ＋１」となるランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、以下のようになる。まず、第１マーク区間では、ビームスポットにガイドトラックＴＲの幅の２倍となる幅を有する判別用記録マークＭＲ２（＃１）が包含されるため、当該第１マーク区間が「＋不定区間（但し、場合によっては＋区間）」であると判定されるおそれがある。第２マーク区間では、ビームスポットにガイドトラックＴＲの幅の２倍となる幅を有する判別用記録マークＭＬ２（＃１）が包含されるため、当該第２マーク区間が「－不定区間（但し、場合によっては－区間）」であると判定されるおそれがある。第３マーク区間では、ビームスポットにガイドトラックＴＲの幅の３倍となる幅を有する判別用記録マークＭＲ２（＃２）が包含されるため、当該第３マーク区間が「＋区間」であると判定される。第４マーク区間では、ビームスポットにガイドトラックＴＲの幅の３倍となる幅を有する判別用記録マークＭＬ２（＃２）が包含されるため、当該第４マーク区間が「－区間」であると判定される。従って、図２５に示す例によれば、トラック番号が「ｋ＋１」となるランドトラックＬＴをトレースする場合には、第３マーク区間及び第４マーク区間において、「＋区間」、「－区間」と判定される。 Similarly, as shown in the second graph of FIG. 25, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 1” is as follows. It becomes like this. First, in the first mark section, the recording mark MR2 (# 1) for determination having a width that is twice the width of the guide track TR is included in the beam spot. Therefore, the first mark section is “+ undefined section ( However, in some cases, it may be determined that it is “+ section)”. In the second mark section, the recording spot ML2 (# 1) having a width that is twice the width of the guide track TR is included in the beam spot. Therefore, the second mark section is “−indefinite section (however, In some cases, it may be determined as “-section)”. In the third mark section, the recording mark MR2 (# 2) for determination having a width that is three times the width of the guide track TR is included in the beam spot, and therefore the third mark section is “+ section”. Determined. In the fourth mark section, the recording mark ML2 (# 2) for determination having a width that is three times the width of the guide track TR is included in the beam spot, so that the fourth mark section is “−section”. Determined. Therefore, according to the example shown in FIG. 25, when the land track LT having the track number “k + 1” is traced, the “+ section” and “− section” in the third mark section and the fourth mark section Determined.
　同様に、図２５の３番目のグラフに示すように、トラック番号が「ｋ＋３」となるランドトラックＬＴをトレースするガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号の信号レベルは、以下のようになる。まず、第１マーク区間では、ビームスポットにガイドトラックＴＲの幅の２倍となる幅を有する判別用記録マークＭＲ２（＃１）が包含されるため、当該第１マーク区間が「－不定区間（但し、場合によっては－区間）」であると判定されるおそれがある。第２マーク区間では、ビームスポットに判別用記録マークＭＬ２及びＭＲ２が包含されないため、当該第２マーク区間が「０区間」であると判定される。第３マーク区間では、ビームスポットにガイドトラックＴＲの幅の３倍となる幅を有する判別用記録マークＭＲ２（＃２）が包含されるため、当該第３マーク区間が「－区間」であると判定される。第４マーク区間では、ビームスポットにガイドトラックＴＲの幅の３倍となる幅を有する判別用記録マークＭＬ２（＃２）の一部のみが包含されるため、当該第４マーク区間が「－不定区間」若しくは「＋不定区間」であると判定されるおそれがある。従って、図２５に示す例によれば、トラック番号が「ｋ＋３」となるランドトラックＬＴをトレースする場合には、第２マーク区間及び第３マーク区間において、「０区間」、「－区間」と判定される。 Similarly, as shown in the third graph of FIG. 25, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that traces the land track LT with the track number “k + 3” is as follows. It becomes like this. First, since the first mark section includes the determination recording mark MR2 (# 1) having a width that is twice the width of the guide track TR in the beam spot, the first mark section is “−indefinite section ( However, in some cases, it may be determined as “-section)”. In the second mark section, since the recording marks ML2 and MR2 for determination are not included in the beam spot, it is determined that the second mark section is “0 section”. In the third mark section, the recording mark MR2 (# 2) for determination having a width that is three times the width of the guide track TR is included in the beam spot, so that the third mark section is “−section”. Determined. In the fourth mark section, the beam spot includes only a part of the determination recording mark ML2 (# 2) having a width that is three times the width of the guide track TR. There is a risk of being determined to be “section” or “+ indefinite section”. Therefore, according to the example shown in FIG. 25, when the land track LT having the track number “k + 3” is traced, “0 section” and “−section” are displayed in the second mark section and the third mark section. Determined.
　この場合、ガイドレーザ光ＬＢ１がトレースしているランドトラックＬＴがセンタートラックＣＴであるか否かを判別するために、図２６に示すように、まず、第１マーク区間が「０区間」であるか否かが判定される（ステップＳ３１）。 In this case, in order to determine whether or not the land track LT traced by the guide laser beam LB1 is the center track CT, first, the first mark section is “0 section” as shown in FIG. Is determined (step S31).
　ステップＳ３１の判定の結果、第１マーク区間が「０区間」であると判定される場合には（ステップＳ３１：Ｙｅｓ）、ガイドレーザ光ＬＢ１が現在トレースしているランドトラックＬＴがセンタートラックＣＴでないと判別される（ステップＳ３６）。 As a result of the determination in step S31, when it is determined that the first mark section is “0 section” (step S31: Yes), the land track LT currently traced by the guide laser beam LB1 is not the center track CT. Is determined (step S36).
　他方で、ステップＳ３１の判定の結果、第１マーク区間が「０区間」でないと判定される場合には（ステップＳ３１：Ｎｏ）、第２マーク区間が「０区間」であるか否かが判定される（ステップＳ３２）。 On the other hand, if it is determined in step S31 that the first mark section is not “0 section” (step S31: No), it is determined whether or not the second mark section is “0 section”. (Step S32).
　ステップＳ３２の判定の結果、第２マーク区間が「０区間」であると判定される場合には（ステップＳ３２：Ｙｅｓ）、ガイドレーザ光ＬＢ１が現在トレースしているランドトラックＬＴがセンタートラックＣＴでないと判別される（ステップＳ３６）。 As a result of the determination in step S32, when it is determined that the second mark section is “0 section” (step S32: Yes), the land track LT currently traced by the guide laser beam LB1 is not the center track CT. Is determined (step S36).
　他方で、ステップＳ３２の判定の結果、第２マーク区間が「０区間」でないと判定される場合には（ステップＳ３２：Ｎｏ）、第３マーク区間が「＋区間」であるか否かが判定される（ステップＳ３３）。 On the other hand, as a result of the determination in step S32, when it is determined that the second mark section is not “0 section” (step S32: No), it is determined whether or not the third mark section is “+ section”. (Step S33).
　ステップＳ３３の判定の結果、第３マーク区間が「＋区間」でないと判定される場合には（ステップＳ３３：Ｎｏ）、ガイドレーザ光ＬＢ１が現在トレースしているランドトラックＬＴがセンタートラックＣＴでないと判別される（ステップＳ３６）。 As a result of the determination in step S33, if it is determined that the third mark section is not “+ section” (step S33: No), the land track LT currently being traced by the guide laser beam LB1 is not the center track CT. A determination is made (step S36).
　他方で、ステップＳ３３の判定の結果、第３マーク区間が「＋区間」であると判定される場合には（ステップＳ３３：Ｙｅｓ）、第４マーク区間が「－区間」であるか否かが判定される（ステップＳ３４）。 On the other hand, if it is determined in step S33 that the third mark section is “+ section” (step S33: Yes), whether or not the fourth mark section is “−section” is determined. Determination is made (step S34).
　ステップＳ３４の判定の結果、第４マーク区間が「－区間」でないと判定される場合には（ステップＳ３４：Ｎｏ）、ガイドレーザ光ＬＢ１が現在トレースしているランドトラックＬＴがセンタートラックＣＴでないと判別される（ステップＳ３６）。 As a result of the determination in step S34, when it is determined that the fourth mark section is not “−section” (step S34: No), the land track LT currently being traced by the guide laser beam LB1 is not the center track CT. A determination is made (step S36).
　他方で、ステップＳ３４の判定の結果、第４マーク区間が「－区間」であると判定される場合には（ステップＳ３４：Ｙｅｓ）、ガイドレーザ光ＬＢ１が現在トレースしているランドトラックＬＴがセンタートラックＣＴであると判別される（ステップＳ３５）。 On the other hand, as a result of the determination in step S34, when it is determined that the fourth mark section is “−section” (step S34: Yes), the land track LT currently being traced by the guide laser beam LB1 is the center. It is determined that the track is a CT (step S35).
　このように、第３変形例においても、判別用マーク群ＭＧ２を用いて、センタートラックＣＴが好適に判別される。加えて、第３変形例においても、第１変形例において享受することができる各種効果を好適に享受することができる。 Thus, also in the third modified example, the center track CT is suitably discriminated using the discrimination mark group MG2. In addition, also in the 3rd modification, the various effects which can be enjoyed in the 1st modification can be enjoyed suitably.
　更には、第３変形例では、各ランドトラックＬＴをトレースする場合に「０区間」、「＋区間」又は「－区間」であると確実に判定される２つ以上のマーク区間が確保される。その結果、「０区間」、「＋区間」又は「－区間」であると確実に判定される２つ以上のマーク区間を用いて、センタートラックＣＴを判別することができる。従って、センタートラックＣＴの判別の精度を相対的に向上させることができる。 Furthermore, in the third modified example, when each land track LT is traced, two or more mark sections that are surely determined as “0 section”, “+ section”, or “− section” are secured. . As a result, the center track CT can be determined using two or more mark sections that are reliably determined to be “0 section”, “+ section”, or “− section”. Accordingly, it is possible to relatively improve the accuracy of discrimination of the center track CT.
　尚、図２５に示す判別用マーク群ＭＧ２の態様はあくまで一例である。従って、各ランドトラックＬＴをトレースする場合に２つ以上のマーク区間において「０区間」、「＋区間」又は「－区間」であると判定される限りは、判別用マーク群ＭＧ２はどのような態様を有していてもよい。この場合、当然に、図２６に示すフローチャートも、図２５に示す態様以外の態様を示す判別用マーク群ＭＧ２に合わせて変更されることが好ましい。 Note that the mode of the discrimination mark group MG2 shown in FIG. 25 is merely an example. Therefore, as long as each land track LT is traced and determined to be “0 section”, “+ section” or “− section” in two or more mark sections, what kind of mark group MG2 is used for determination You may have an aspect. In this case, as a matter of course, it is preferable that the flowchart shown in FIG. 26 is also changed in accordance with the determination mark group MG2 showing an aspect other than the aspect shown in FIG.
　また、上述した説明では、ランドトラックＬＴに形成される判別用マーク群ＭＧ２について説明している。しかしながら、グルーブトラックＧＴに形成される判別用マーク群ＭＧ２についても同様である。つまり、各グルーブトラックＧＴをトレースする場合に２つ以上のマーク区間において「０区間」、「＋区間」又は「－区間」であると判定されるように、グルーブトラックＧＴに判別用マーク群ＭＧ２が形成されてもよい。 In the above description, the determination mark group MG2 formed on the land track LT is described. However, the same applies to the discrimination mark group MG2 formed on the groove track GT. That is, when tracing each groove track GT, the mark group MG2 for determination is added to the groove track GT so that it is determined that it is “0 section”, “+ section” or “− section” in two or more mark sections. May be formed.
　（３－４）第４変形例
　続いて、図２７及び図２８を参照して、第４変形例について説明する。図２７は、ランドトラックＬＴに形成される第４変形例の判別用マーク群ＭＧ２の構成を示す平面図である。図２８は、図２７に示す第４変形例の判別用マーク群ＭＧ２を用いてセンタートラックＣＴを判別する動作を示すフローチャートである。 (3-4) Fourth Modified Example Next, with reference to FIGS. 27 and 28, a fourth modified example will be described. FIG. 27 is a plan view showing a configuration of the discrimination mark group MG2 of the fourth modified example formed on the land track LT. FIG. 28 is a flowchart showing an operation of discriminating the center track CT using the discrimination mark group MG2 of the fourth modified example shown in FIG.
　図２７に示すように、第４変形例では、同一のスロットに形成される判別用マーク群ＭＧ２は、各ランドトラックＬＴのトラック中心を基準として左右に等距離シフトした一対の判別用記録マークＭＬ２及びＭＲ２を含んでいる。具体的には、判別用マーク群ＭＧ２は、(i)トラック番号が「ｋ＋３」となるランドトラックＬＴのトラック中心を基準として左右に等距離シフトし且つ異なる回転位相位置（第１及び第２マーク区間）に形成される一対の判別用記録マークＭＬ２（＃１）及びＭＲ２（＃１）と、(ii)トラック番号が「ｋ＋１」となるランドトラックＬＴのトラック中心を基準として左右に等距離シフトし且つ異なる回転位相位置（第３及び第４マーク区間）に形成される一対の判別用記録マークＭＬ２（＃２）及びＭＲ２（＃２）と、(iii)トラック番号が「ｋ－１」となるランドトラックＬＴのトラック中心を基準として左右に等距離シフトし且つ異なる回転位相位置（第５及び第６マーク区間）に形成される一対の判別用記録マークＭＬ２（＃３）及びＭＲ２（＃３）とを含んでいる。 As shown in FIG. 27, in the fourth modified example, the discrimination mark group MG2 formed in the same slot has a pair of discrimination recording marks ML2 shifted equidistantly from side to side with respect to the track center of each land track LT. And MR2. Specifically, the discrimination mark group MG2 is (i) shifted equidistantly from side to side with respect to the track center of the land track LT having the track number “k + 3” and different rotational phase positions (first and second marks). (Ii) Equal distance shift from side to side with reference to the track center of the land track LT with the track number “k + 1” and the pair of discrimination recording marks ML2 (# 1) and MR2 (# 1) formed in the section) And a pair of discrimination recording marks ML2 (# 2) and MR2 (# 2) formed at different rotational phase positions (third and fourth mark sections), and (iii) the track number is “k−1”. A pair of discriminating recording marks ML2 (# 3) and MR that are shifted equidistant from side to side with respect to the track center of the land track LT and formed at different rotational phase positions (fifth and sixth mark sections) Contains (# 3) and.
　第４変形例では、第１及び第２マーク区間に形成された一対の判別用記録マークＭＬ２（＃１）及びＭＲ２（＃１）を用いて、現在トレースしているランドトラックＬＴが、センタートラックＣＴの外側に位置する（つまり、センタートラックＣＴの外側に隣接する）ランドトラックＬＴであるか否かが判別される。具体的には、図２８に示すように、第１マーク区間が「－区間」であると判定され（ステップＳ４１：Ｙｅｓ）且つ第２マーク区間が「＋区間」であると判定される（ステップＳ４２：Ｙｅｓ）場合に、現在トレースしているランドトラックＬＴが、センタートラックＣＴの外側に位置するランドトラックＬＴであると判別される（ステップＳ４７）。 In the fourth modification, the land track LT currently being traced using the pair of discrimination recording marks ML2 (# 1) and MR2 (# 1) formed in the first and second mark sections is the center track. It is determined whether or not the land track LT is located outside the CT (that is, adjacent to the outside of the center track CT). Specifically, as shown in FIG. 28, the first mark section is determined to be “− section” (step S41: Yes), and the second mark section is determined to be “+ section” (step In the case of S42: Yes), it is determined that the currently tracked land track LT is a land track LT located outside the center track CT (step S47).
　同様に、第４変形例では、第３及び第４マーク区間に形成された一対の判別用記録マークＭＬ２（＃２）及びＭＲ２（＃２）を用いて、現在トレースしているランドトラックＬＴがセンタートラックＣＴであるか否かが判別される。具体的には、図２８に示すように、第３マーク区間が「－区間」であると判定され（ステップＳ４３：Ｙｅｓ）且つ第４マーク区間が「＋区間」であると判定される（ステップＳ４４：Ｙｅｓ）場合に、現在トレースしているランドトラックＬＴがセンタートラックＣＴであると判別される（ステップＳ４８）。 Similarly, in the fourth modification, the land track LT currently being traced is determined using the pair of determination recording marks ML2 (# 2) and MR2 (# 2) formed in the third and fourth mark sections. It is determined whether or not the center track CT. Specifically, as shown in FIG. 28, it is determined that the third mark section is “−section” (step S43: Yes) and the fourth mark section is determined to be “+ section” (step S43). S44: Yes), it is determined that the currently tracked land track LT is the center track CT (step S48).
　同様に、第４変形例では、第５及び第６マーク区間に形成された一対の判別用記録マークＭＬ２（＃３）及びＭＲ２（＃３）を用いて、現在トレースしているランドトラックＬＴが、センタートラックＣＴの内側に位置する（つまり、センタートラックＣＴの内側に隣接する）ランドトラックＬＴであるか否かが判別される。具体的には、図２８に示すように、第５マーク区間が「－区間」であると判定され（ステップＳ４５：Ｙｅｓ）且つ第６マーク区間が「＋区間」であると判定される（ステップＳ４６：Ｙｅｓ）場合に、現在トレースしているランドトラックＬＴが、センタートラックＣＴの内側に位置するランドトラックＬＴであると判別される（ステップＳ４９）。 Similarly, in the fourth modification, the land track LT currently being traced is determined using a pair of determination recording marks ML2 (# 3) and MR2 (# 3) formed in the fifth and sixth mark sections. It is determined whether or not the land track LT is located inside the center track CT (that is, adjacent to the inside of the center track CT). Specifically, as shown in FIG. 28, it is determined that the fifth mark section is “− section” (step S45: Yes), and the sixth mark section is determined to be “+ section” (step S45). In the case of S46: Yes), it is determined that the currently tracked land track LT is the land track LT located inside the center track CT (step S49).
　このように、第４変形例においても、判別用マーク群ＭＧ２を用いて、センタートラックＣＴが好適に判別される。加えて、第４変形例においても、第１変形例において享受することができる各種効果を好適に享受することができる。 Thus, also in the fourth modified example, the center track CT is suitably discriminated using the discrimination mark group MG2. In addition, also in the fourth modification, various effects that can be enjoyed in the first modification can be suitably enjoyed.
　尚、図２７に示す判別用マーク群ＭＧ２は、(i)センタートラックＣＴのトラック中心を基準として左右に等距離シフトしている一対の判別用記録マークＭＬ２（＃１）及びＭＲ２（＃３）と、(ii)センタートラックＣＴのトラック中心を基準として左右に等距離シフトしている一対の判別用記録マークＭＬ２（＃３）及びＭＲ２（＃１）と、(iii)センタートラックＣＴのトラック中心を基準として左右に等距離シフトしている一対の判別用記録マークＭＬ２（＃２）及びＭＲ２（＃２）とを含んでいるとも言える。従って、第４変形例の判別用マーク群ＭＧ２もまた、センタートラックＣＴのトラック中心を基準として左右に等距離シフトした一対の判別用記録マークＭＬ２及びＭＲ２を複数含んでいるとも言える。 Note that the discrimination mark group MG2 shown in FIG. 27 includes (i) a pair of discrimination recording marks ML2 (# 1) and MR2 (# 3) that are shifted equidistant from side to side with respect to the track center of the center track CT. And (ii) a pair of discriminating recording marks ML2 (# 3) and MR2 (# 1) that are shifted equidistantly with respect to the center of the track of the center track CT, and (iii) the track center of the center track CT It can be said that it includes a pair of discriminating recording marks ML2 (# 2) and MR2 (# 2) that are shifted equidistantly to the left and right with reference to. Therefore, it can be said that the discrimination mark group MG2 of the fourth modified example also includes a plurality of a pair of discrimination recording marks ML2 and MR2 shifted equidistantly to the left and right with respect to the track center of the center track CT.
　（４）記録再生装置
　続いて、図２９から図３７を参照して、上述した光ディスク１１に対する記録動作及び再生動作の少なくとも一方を行う記録再生装置１００について説明する。 (4) Recording / Reproducing Device Next, a recording / reproducing device 100 that performs at least one of the recording operation and the reproducing operation with respect to the optical disc 11 will be described with reference to FIGS. 29 to 37.
　（４－１）記録再生装置の構成
　はじめに、図２９を参照して、本実施例の記録再生装置１００の構成について説明する。図２９は、本実施例の記録再生装置１００の構成を示すブロック図である。 (4-1) Configuration of Recording / Reproducing Device First, the configuration of the recording / reproducing device 100 of the present embodiment will be described with reference to FIG. FIG. 29 is a block diagram showing the configuration of the recording / reproducing apparatus 100 of the present embodiment.
　図２９に示すように、記録再生装置１００は、ディスクドライブ１０１と、ホストコンピュータ２０１とを備えている。 As shown in FIG. 29, the recording / reproducing apparatus 100 includes a disk drive 101 and a host computer 201.
　ディスクドライブ１０１は、光ピックアップ（ＰＵ：Pick Up）１０２と、信号記録再生部１０３と、スピンドルモータ１０４と、バス１０６と、ＣＰＵ１１１と、メモリ１１２と、データ入出力制御部１１３とを備える。光ディスク１１に対する記録動作（特に、所望の記録層１３に対する記録動作）が行われる場合には、光ピックアップ１０２から、光ピックアップ１０２が有する対物レンズ１０２Ｌ（図２参照）を介して、ガイドレーザ光ＬＢ１及び記録再生レーザ光ＬＢ２が照射される。光ディスク１１に対する再生動作（特に、所望の記録層１３に対する再生動作）が行われる場合には、光ピックアップ１０２から、対物レンズ１０２Ｌを介して、記録再生レーザ光ＬＢ２のみが又はガイドレーザ光ＬＢ１及び記録再生レーザ光ＬＢ２の双方が照射される。 The disk drive 101 includes an optical pickup (PU) 102, a signal recording / reproducing unit 103, a spindle motor 104, a bus 106, a CPU 111, a memory 112, and a data input / output control unit 113. When a recording operation on the optical disc 11 (particularly, a recording operation on a desired recording layer 13) is performed, the guide laser beam LB1 is transmitted from the optical pickup 102 via the objective lens 102L (see FIG. 2) of the optical pickup 102. Further, the recording / reproducing laser beam LB2 is irradiated. When a reproducing operation on the optical disc 11 (particularly a reproducing operation on a desired recording layer 13) is performed, only the recording / reproducing laser beam LB2 or the guide laser beam LB1 and the recording are performed from the optical pickup 102 via the objective lens 102L. Both reproduction laser beams LB2 are irradiated.
　ホストコンピュータ２０１は、操作／表示制御部２０２と、操作ボタン２０３と、表示パネル２０４と、バス２０６と、ＣＰＵ２１１と、メモリ２１２と、データ入出力制御部２１３とを備える。光ディスク１１に対する記録動作（特に、所望の記録層１３に対する記録動作）が行われる場合には、所望の記録層１３に記録すべきデータが、データ入出力制御部２１３から入力される。光ディスク１１に対する再生動作（特に、所望の記録層１３に対する再生動作）が行われる場合には、再生されたデータが、データ入出力制御部２１３から出力される。 The host computer 201 includes an operation / display control unit 202, an operation button 203, a display panel 204, a bus 206, a CPU 211, a memory 212, and a data input / output control unit 213. When a recording operation on the optical disc 11 (particularly, a recording operation on the desired recording layer 13) is performed, data to be recorded on the desired recording layer 13 is input from the data input / output control unit 213. When a reproducing operation for the optical disc 11 (particularly, a reproducing operation for a desired recording layer 13) is performed, the reproduced data is output from the data input / output control unit 213.
　光ピックアップ１０２は、ガイドレーザ光ＬＢ１を発する赤色半導体レーザ光源と、記録再生レーザ光ＬＢ２を発する青色半導体レーザ光源と、対物レンズ１０２Ｌ、プリズム及びミラー等を含む合成分離光学系とを備える。光ピックアップ１０２は、共通の対物レンズ１０２Ｌを介して、ガイドレーザ光ＬＢ１及び記録再生レーザ光ＬＢ２を同軸的に且つ異なるフォーカスにて（図１及び図２参照）照射する。 The optical pickup 102 includes a red semiconductor laser light source that emits a guide laser beam LB1, a blue semiconductor laser light source that emits a recording / reproducing laser beam LB2, and a combining / separating optical system including an objective lens 102L, a prism, a mirror, and the like. The optical pickup 102 irradiates the guide laser beam LB1 and the recording / reproducing laser beam LB2 coaxially and with different focus (see FIGS. 1 and 2) through a common objective lens 102L.
　光ピックアップ１０２は、ガイド層１２からのガイドレーザ光ＬＢ１の戻り光を受光する二分割或いは四分割のガイド受光素子と、所望の記録層１３からの記録再生レーザ光ＬＢ２の戻り光を受光する二分割或いは四分割の記録再生受光素子とを備える。光ピックアップ１０２は、光ディスク１１に対する記録動作（特に、所望の記録層１３に対する記録動作）が行われる場合には、相対的に高強度の記録再生レーザ光ＬＢ２を出射する。一方で、光ピックアップ１０２は、光ディスク１１に対する再生動作（特に、所望の記録層１３に対する再生動作）が行われる場合には、相対的に低強度の記録再生レーザ光ＬＢ２を出射する。 The optical pickup 102 receives a two-divided or four-divided guide light receiving element that receives the return light of the guide laser light LB1 from the guide layer 12, and a second light receiving the return light of the recording / reproducing laser light LB2 from the desired recording layer 13. And a divided or quadrant recording / reproducing light receiving element. The optical pickup 102 emits a relatively high-intensity recording / reproducing laser beam LB2 when a recording operation on the optical disc 11 (particularly, a recording operation on a desired recording layer 13) is performed. On the other hand, the optical pickup 102 emits a relatively low-intensity recording / reproducing laser beam LB2 when a reproducing operation on the optical disc 11 (particularly, a reproducing operation on a desired recording layer 13) is performed.
　光ピックアップ１０２が備えるガイド受光素子は、ガイドレーザ光ＬＢ１の戻り光を受光することで、当該戻り光に起因したプッシュプル信号を生成する。このプッシュプル信号に基づいて、トラッキング制御や判別用マーク群ＭＧ２に応じたセンタートラックＣＴの判別や情報用マーク群ＭＧ１に応じたビットデータの読み取りが行われる。一方で、光ピックアップ１０２が備える記録再生受光素子は、ディスク１１に対する再生動作（特に、所望の記録層１３に対する再生動作）が行われる場合には、記録再生レーザ光ＬＢ２の戻り光を受光することで、当該戻り光に起因したＲＦ信号を生成する。このＲＦ信号に基づいて、所望の記録層１３に記録されたデータが再生される。また、光ピックアップ１０２が備える記録再生受光素子は、記録再生レーザ光ＬＢ２の戻り光を受光することで、当該戻り光に起因したプッシュプル信号を生成してもよい。このプッシュプル信号に基づいて、トラッキング制御が行われてもよい。 The guide light receiving element included in the optical pickup 102 receives the return light of the guide laser light LB1, thereby generating a push-pull signal resulting from the return light. Based on this push-pull signal, tracking control, discrimination of the center track CT corresponding to the discrimination mark group MG2, and reading of bit data corresponding to the information mark group MG1 are performed. On the other hand, the recording / reproducing light receiving element included in the optical pickup 102 receives the return light of the recording / reproducing laser beam LB2 when a reproducing operation on the disk 11 (particularly, a reproducing operation on the desired recording layer 13) is performed. Thus, an RF signal resulting from the return light is generated. Based on this RF signal, the data recorded on the desired recording layer 13 is reproduced. The recording / reproducing light receiving element included in the optical pickup 102 may generate a push-pull signal caused by the return light by receiving the return light of the recording / reproducing laser beam LB2. Tracking control may be performed based on this push-pull signal.
　メモリ１１２及びメモリ２１２は、(i)記録再生装置１０１におけるＣＰＵ１１１等の各要素、及びホストコンピュータ２０１におけるＣＰＵ２１１等の各要素を、次に説明する記録動作及び再生動作が行われるように制御するためのコンピュータプログラム、並びに(ii)記録再生動作に必要な各種データを、バス１０６、バス２０６等を介して一時的又は恒久的に保持するのに適宜用いられる。 The memory 112 and the memory 212 are for controlling (i) each element such as the CPU 111 in the recording / reproducing apparatus 101 and each element such as the CPU 211 in the host computer 201 so that a recording operation and a reproducing operation described below are performed. The computer program and (ii) various data necessary for the recording / reproducing operation are appropriately used to temporarily or permanently hold the data via the bus 106, the bus 206, and the like.
　続いて、図３０を参照して、信号記録再生部１０３のより詳細な構成について説明する。図３０は、信号記録再生部１０３の構成を示すブロック図である。 Next, a more detailed configuration of the signal recording / reproducing unit 103 will be described with reference to FIG. FIG. 30 is a block diagram showing a configuration of the signal recording / reproducing unit 103.
　図３０に示すように、信号記録再生部１０３は、トラッキング制御回路１２０と、マーク群検出回路１３０とを備えている。 As shown in FIG. 30, the signal recording / reproducing unit 103 includes a tracking control circuit 120 and a mark group detection circuit 130.
　トラッキング制御回路１２０は、ガイド受光素子が出力するプッシュプル信号（つまり、ガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号）に基づいて、トラッキング制御を行う。例えば、トラッキング制御回路１２０は、プッシュプル信号に基づいてトラッキング制御信号を生成すると共に、当該トラッキング制御信号を光ピックアップ１０２（より具体的には、光ピックアップ１０２をトラッキング方向に駆動するアクチュエータ）に出力することで、トラッキング制御を行う。尚、トラッキング制御そのものについては、既存のトラッキング制御と同様の態様で行われてもよいため、詳細な説明を省略する。 The tracking control circuit 120 performs tracking control based on a push-pull signal output from the guide light receiving element (that is, a push-pull signal generated from the return light of the guide laser beam LB1). For example, the tracking control circuit 120 generates a tracking control signal based on the push-pull signal and outputs the tracking control signal to the optical pickup 102 (more specifically, an actuator that drives the optical pickup 102 in the tracking direction). By doing so, tracking control is performed. The tracking control itself may be performed in the same manner as the existing tracking control, and thus detailed description thereof is omitted.
　マーク群検出回路１３０は、ガイド受光素子が出力するプッシュプル信号（つまり、ガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号）に基づいて、ガイド層１２に形成された情報用マーク群ＭＧ１及び判別用マーク群ＭＧ２を検出する。より具体的には、マーク群検出回路１３０は、ガイド受光素子が出力するプッシュプル信号の信号レベルの変動を監視することで、情報用マーク群ＭＧ１を検出すると共に、当該情報用マーク群ＭＧ１が示す同期データ及びビットデータを検出する。同期データ及びビットデータを検出する際には、マーク群検出回路１３０は、ガイド受光素子が出力するプッシュプル信号の信号レベルの変動を監視することで、判別用マーク群ＭＧ２を検出すると共に、当該判別用マーク群ＭＧ２に基づいて現在トレースしているガイドトラックＴＲがセンタートラックＣＴであるか否かを判別する。 The mark group detection circuit 130 is based on the push-pull signal output from the guide light receiving element (that is, the push-pull signal generated from the return light of the guide laser beam LB1), and the information mark group MG1 formed on the guide layer 12. Then, the discrimination mark group MG2 is detected. More specifically, the mark group detection circuit 130 detects the information mark group MG1 by monitoring fluctuations in the signal level of the push-pull signal output from the guide light receiving element, and the information mark group MG1 The synchronization data and bit data shown are detected. When detecting the synchronization data and the bit data, the mark group detection circuit 130 detects the discrimination mark group MG2 by monitoring the fluctuation of the signal level of the push-pull signal output from the guide light receiving element, and Based on the determination mark group MG2, it is determined whether or not the guide track TR currently being traced is the center track CT.
　このような情報用マーク群ＭＧ１及び判別用マーク群ＭＧ２を検出するために、マーク群検出回路１３０は、ＬＰＦ（Low Path Filter）１３１０と、ＬＰＦ１３１１と、Ｓ／Ｈ（Sample Hold）回路１３１２と、Ｓ／Ｈ回路１３１３と、差分器１３１４と、比較器１３１５と、同期データ検出器１３１６と、ワードマーカ検出器１３１８と、ニブルマーカ検出器１３１９と、プリデータ検出器１３２０と、バッファメモリ１３２１と、データ蓄積制御部１３２２と、誤り訂正部１３２３と、検出ウインドウ生成部１３２４と、再生タイミング生成部１３２５とを備えている。 In order to detect such information mark group MG1 and discrimination mark group MG2, the mark group detection circuit 130 includes an LPF (Low Path Filter) 1310, an LPF 1311, an S / H (Sample Hold) circuit 1312, S / H circuit 1313, differencer 1314, comparator 1315, synchronous data detector 1316, word marker detector 1318, nibble marker detector 1319, pre-data detector 1320, buffer memory 1321, and data An accumulation control unit 1322, an error correction unit 1323, a detection window generation unit 1324, and a reproduction timing generation unit 1325 are provided.
　ガイド受光素子が出力するプッシュプル信号は、ＬＰＦ１３１０及び１３１１の双方に入力される。 The push-pull signal output from the guide light receiving element is input to both LPFs 1310 and 1311.
　ＬＰＦ１３１０は、プッシュプル信号のノイズを除去するためのフィルタであって、例えば、情報用マーク群ＭＧ１及び判別用マーク群ＭＧ２に起因した周波数の波形が透過するカットオフ周波数を有するフィルタである。ＬＰＦ１３１０を透過したプッシュプル信号は、Ｓ／Ｈ回路１３１２において所定のタイミング毎にサンプルホールドされる。Ｓ／Ｈ回路１３１２においてサンプルホールドされたプッシュプル信号（つまり、信号レベル）は、差分器１３１４に入力される。尚、Ｓ／Ｈ回路１３１２においてサンプルホールドされたプッシュプル信号の信号レベルは、情報用マーク群ＭＧ１及び判別用マーク群ＭＧ２のパターンによって変動し得る。 The LPF 1310 is a filter for removing noise of the push-pull signal, and is a filter having a cutoff frequency through which the waveform of the frequency caused by the information mark group MG1 and the discrimination mark group MG2 is transmitted, for example. The push-pull signal that has passed through the LPF 1310 is sampled and held by the S / H circuit 1312 at every predetermined timing. The push-pull signal (that is, the signal level) sampled and held in the S / H circuit 1312 is input to the differentiator 1314. Note that the signal level of the push-pull signal sampled and held in the S / H circuit 1312 may vary depending on the patterns of the information mark group MG1 and the determination mark group MG2.
　一方で、ＬＰＦ１３１１は、プッシュプル信号の偏心成分に起因した波形がその位相も含めて透過するカットオフ周波数を有するフィルタである。ＬＰＦ１３１１を透過したプッシュプル信号は、Ｓ／Ｈ回路１３１３において所定のタイミング毎にサンプルホールドされる。Ｓ／Ｈ回路１３１３においてサンプルホールドされたプッシュプル信号（つまり、信号レベル）は、差分器１３１４に入力される。尚、Ｓ／Ｈ回路１３１３においてサンプルホールドされたプッシュプル信号の信号レベルは、プッシュプル信号の信号レベルの基準値（いわゆる、ゼロレベルであり、実質的にはＤＣ成分）に相当する。 On the other hand, the LPF 1311 is a filter having a cutoff frequency through which a waveform caused by the eccentric component of the push-pull signal is transmitted including its phase. The push-pull signal that has passed through the LPF 1311 is sampled and held at a predetermined timing in the S / H circuit 1313. The push-pull signal (that is, the signal level) sampled and held in the S / H circuit 1313 is input to the differentiator 1314. Note that the signal level of the push-pull signal sampled and held in the S / H circuit 1313 corresponds to a reference value of the signal level of the push-pull signal (so-called zero level, substantially DC component).
　差分器１３１４は、Ｓ／Ｈ回路１３１２においてサンプルホールドされたプッシュプル信号の信号レベルから、Ｓ／Ｈ回路１３１３においてサンプルホールドされたプッシュプル信号の信号レベルを除算する。その結果、差分器１３１４は、基準値（いわゆる、ゼロレベル）の変動の影響を排除したプッシュプル信号の信号レベルを出力する。 The subtractor 1314 divides the signal level of the push-pull signal sampled and held in the S / H circuit 1313 from the signal level of the push-pull signal sampled and held in the S / H circuit 1312. As a result, the differentiator 1314 outputs the signal level of the push-pull signal from which the influence of the fluctuation of the reference value (so-called zero level) is eliminated.
　比較器１３１５は、差分器１３１４から出力されるプッシュプル信号（特に、情報用マーク群ＭＧ１に対応するプッシュプル信号）の信号レベルを所定の閾値と比較する。その結果、比較器１３１５は、プッシュプル信号の信号レベルが、「０」であるのか、「＋」であるのか、又は「－」であるのかを判定する。 The comparator 1315 compares the signal level of the push-pull signal (particularly, the push-pull signal corresponding to the information mark group MG1) output from the differentiator 1314 with a predetermined threshold value. As a result, the comparator 1315 determines whether the signal level of the push-pull signal is “0”, “+”, or “−”.
　加えて、比較器１３１５は、差分器１３１４から出力されるプッシュプル信号（特に、判別用マーク群ＭＧ２に対応するプッシュプル信号）の信号レベルを所定の閾値と比較する。と、上述した第１閾値ａ及び第２閾値ｂとを比較する。その結果、比較器１３１５は、プッシュプル信号の信号レベルが、「０」であるのか、「＋」であるのか、「－」であるのか「＋不定」であるのか、「－不定」であるのか、又は「隣接でない」であるのかを判定する。言い換えれば、比較器１３１５は、プッシュプル信号が検出されているマーク区間が、「０区間」であるのか、「＋区間」であるのか、「－区間」であるのか、「＋不定区間」であるのか、「－不定区間」であるのか、又は「隣接でない区間」であるのかを判定する。 In addition, the comparator 1315 compares the signal level of the push-pull signal (particularly, the push-pull signal corresponding to the discrimination mark group MG2) output from the differentiator 1314 with a predetermined threshold value. And the above-described first threshold value a and second threshold value b are compared. As a result, the comparator 1315 determines whether the signal level of the push-pull signal is “0”, “+”, “−”, “+ indeterminate”, or “−indeterminate”. Or “not adjacent”. In other words, the comparator 1315 determines whether the mark interval in which the push-pull signal is detected is “0 interval”, “+ interval”, “− interval”, or “+ indefinite interval”. It is determined whether there is a “−indefinite section” or a “non-adjacent section”.
　同期データ検出器１３１６は、比較器１３１５における比較結果に基づいて、同期データを検出する。つまり、同期データ検出器１３１６は、比較器１３１５における比較結果に基づいて、同期データに相当する態様で信号レベルが変動するプッシュプル信号を検出することで、同期データを検出する。 The synchronization data detector 1316 detects synchronization data based on the comparison result in the comparator 1315. That is, the synchronization data detector 1316 detects the synchronization data by detecting a push-pull signal whose signal level varies in a manner corresponding to the synchronization data based on the comparison result in the comparator 1315.
　判別マーク群検出器１３１７は、比較器１３１５における比較結果に基づいて、判別マーク群ＭＧ２を検出する。判別マーク群検出器１３１７による判別マーク群ＭＧ２の検出は、同期データ検出器１３１６によって同期データが検出された直後に行われることが好ましい。というのも、本実施例では、上述したように、判別マーク群ＭＧ２は、同期データに相当する情報用マーク群ＭＧ１の直後に形成されるからである（図１４参照）。その結果、判別マーク群検出器１３１７は、比較器１３１５における比較結果に基づいて、ガイドレーザ光ＬＢ１がトレースしているガイドトラックＴＲがセンタートラックＣＴであるか否かを判定する。 The discrimination mark group detector 1317 detects the discrimination mark group MG2 based on the comparison result in the comparator 1315. The detection of the discrimination mark group MG2 by the discrimination mark group detector 1317 is preferably performed immediately after the synchronization data is detected by the synchronization data detector 1316. This is because in the present embodiment, as described above, the discrimination mark group MG2 is formed immediately after the information mark group MG1 corresponding to the synchronization data (see FIG. 14). As a result, the discrimination mark group detector 1317 determines whether or not the guide track TR traced by the guide laser beam LB1 is the center track CT based on the comparison result in the comparator 1315.
　ワードマーカ検出器１３１８は、比較器１３１５における比較結果に基づいて、ビットデータの一例であるワードマーカを検出する。つまり、ワードマーカ検出器１３１８は、比較器１３１５における比較結果に基づいて、ワードマーカに相当する態様で信号レベルが変動するプッシュプル信号を検出することで、ワードマーカを検出する。尚、ワードマーカについては後述する（図３２参照）。 The word marker detector 1318 detects a word marker which is an example of bit data based on the comparison result in the comparator 1315. That is, the word marker detector 1318 detects a word marker by detecting a push-pull signal whose signal level varies in a manner corresponding to the word marker based on the comparison result in the comparator 1315. The word marker will be described later (see FIG. 32).
　ワードマーカ検出器１３１８によるワードマーカの検出は、ガイドレーザ光ＬＢ１がトレースしているガイドトラックＴＲがセンタートラックＣＴであると判別マーク群検出器１３１７によって判定された場合に行われる。つまり、ガイドレーザ光ＬＢ１がトレースしているガイドトラックＴＲがセンタートラックＣＴでないと判別マーク群検出器１３１７によって判定された場合には、ワードマーカ検出器１３１８は、仮にプッシュプル信号が入力されていたとしても、ワードマーカを検出しない。 The detection of the word marker by the word marker detector 1318 is performed when the discrimination mark group detector 1317 determines that the guide track TR traced by the guide laser beam LB1 is the center track CT. That is, if the determination mark group detector 1317 determines that the guide track TR traced by the guide laser beam LB1 is not the center track CT, the word marker detector 1318 has been temporarily input with a push-pull signal. However, the word marker is not detected.
　ニブルマーカ検出器１３１９は、比較器１３１５における比較結果に基づいて、ビットデータの一例であるニブルマーカを検出する。つまり、ニブルマーカ検出器１３１９は、比較器１３１５における比較結果に基づいて、ニブルマーカに相当する態様で信号レベルが変動するプッシュプル信号を検出することで、ニブルマーカを検出する。尚、ニブルマーカについては後述する（図３２参照）。 The nibble marker detector 1319 detects a nibble marker which is an example of bit data based on the comparison result in the comparator 1315. That is, the nibble marker detector 1319 detects the nibble marker by detecting a push-pull signal whose signal level varies in a manner corresponding to the nibble marker based on the comparison result in the comparator 1315. The nibble marker will be described later (see FIG. 32).
　ニブルマーカ検出器１３１９によるニブルマーカの検出は、ガイドレーザ光ＬＢ１がトレースしているガイドトラックＴＲがセンタートラックＣＴであると判別マーク群検出器１３１７によって判定された場合に行われる。つまり、ガイドレーザ光ＬＢ１がトレースしているガイドトラックＴＲがセンタートラックＣＴでないと判別マーク群検出器１３１７によって判定された場合には、ニブルマーカ検出器１３１９は、仮にプッシュプル信号が入力されていたとしても、ニブルマーカを検出しない。 The detection of the nibble marker by the nibble marker detector 1319 is performed when the determination mark group detector 1317 determines that the guide track TR traced by the guide laser beam LB1 is the center track CT. That is, if the determination mark group detector 1317 determines that the guide track TR traced by the guide laser beam LB1 is not the center track CT, the nibble marker detector 1319 assumes that a push-pull signal has been input. Does not detect nibble markers.
　プリデータ検出器１３２０は、比較器１３１５における比較結果に基づいて、ビットデータの一例であるプリデータ（つまり、プリフォーマット情報そのもの）を検出する。つまり、プリデータ検出器１３２０は、比較器１３１５における比較結果に基づいて、ワードマーカ及びニブルマーカ以外のビットデータを、プリフォーマット情報として検出する。 The pre-data detector 1320 detects pre-data (that is, pre-format information itself) that is an example of bit data based on the comparison result in the comparator 1315. That is, the predata detector 1320 detects bit data other than the word marker and nibble marker as preformat information based on the comparison result in the comparator 1315.
　プリデータ検出器１３２０によるプリフォーマット情報の検出は、ガイドレーザ光ＬＢ１がトレースしているガイドトラックＴＲがセンタートラックＣＴであると判別マーク群検出器１３１７によって判定された場合に行われる。つまり、ガイドレーザ光ＬＢ１がトレースしているガイドトラックＴＲがセンタートラックＣＴでないと判別マーク群検出器１３１７によって判定された場合には、プリデータ検出器１３２０は、仮にプッシュプル信号が入力されていたとしても、プリフォーマット情報を検出しない。 The detection of the preformat information by the predata detector 1320 is performed when the discrimination mark group detector 1317 determines that the guide track TR traced by the guide laser beam LB1 is the center track CT. In other words, if the determination mark group detector 1317 determines that the guide track TR traced by the guide laser beam LB1 is not the center track CT, the pre-data detector 1320 has temporarily received a push-pull signal. However, preformat information is not detected.
　バッファメモリ１３２１は、データ蓄積制御部１３２３の制御の下で、プリデータ検出器１３２０によって検出されたプリフォーマット情報を一時的に保存する。 The buffer memory 1321 temporarily stores the preformat information detected by the predata detector 1320 under the control of the data accumulation control unit 1323.
　データ蓄積制御部１３２２は、プリデータ検出器１３２０が検出したプリフォーマット情報が、後述するＥＣＣブロックの単位で順番にバッファメモリ１３２１に保存されるように、バッファメモリ１３２１を制御する。つまり、データ蓄積制御部１３２２は、ＥＣＣブロックの単位のプリフォーマット情報（言い換えれば、ワードの単位のプリフォーマット情報）が順番に保存されるように、バッファメモリ１３２１を制御する。尚、バッファメモリ１３２１に保存されるプリフォーマット情報は、ガイドレーザ光ＬＢ１がトレースしているガイドトラックＴＲがセンタートラックＣＴであると判定された場合にプリデータ検出器１３２０によって検出されたプリフォーマット情報であることは、上述したとおりである。 The data accumulation control unit 1322 controls the buffer memory 1321 so that the preformat information detected by the predata detector 1320 is stored in the buffer memory 1321 in order of ECC blocks described later. That is, the data accumulation control unit 1322 controls the buffer memory 1321 so that preformat information in units of ECC blocks (in other words, preformat information in units of words) is stored in order. Note that the preformat information stored in the buffer memory 1321 is preformat information detected by the predata detector 1320 when it is determined that the guide track TR traced by the guide laser beam LB1 is the center track CT. This is as described above.
　誤り訂正部１３２３は、バッファメモリ１３２１に保存されたプリフォーマット情報に対して誤り訂正処理（ＥＣＣ処理：Error Correction Code処理）を行う。ＥＣＣ処理が行われたプリフォーマット情報は、記録動作及び再生動作の際に参照されるべく、ＣＰＵ１１１へと転送される。 The error correction unit 1323 performs error correction processing (ECC processing: Error Correction Code processing) on the preformat information stored in the buffer memory 1321. The preformat information that has been subjected to the ECC processing is transferred to the CPU 111 so as to be referred to during the recording operation and the reproducing operation.
　検出ウインドウ生成部１３２４は、比較器１３１５がプッシュプル信号の信号レベルと第１閾値ａ及び第２閾値ｂとを比較する際のタイミングを規定する検出ウインドウを生成する。その結果、比較器１３１５は、検出ウインドウの単位で、プッシュプル信号の信号レベルと第１閾値ａ及び第２閾値ｂとを比較する。加えて、同期データ検出器１３１７による同期データの検出、ワードマーカ検出器１３１８によるワードマーカの検出、ニブルマーカ検出器１３１９によるニブルマーカの検出及びプリデータ検出器１３２０によるプリフォーマット情報の検出もまた、検出ウインドウの単位で行われてもよい。従って、検出ウインドウ生成部１３２４は、このような検出ウインドウを生成することが好ましい。 The detection window generation unit 1324 generates a detection window that defines the timing when the comparator 1315 compares the signal level of the push-pull signal with the first threshold value a and the second threshold value b. As a result, the comparator 1315 compares the signal level of the push-pull signal with the first threshold value a and the second threshold value b in units of detection windows. In addition, the detection of the synchronization data by the synchronization data detector 1317, the detection of the word marker by the word marker detector 1318, the detection of the nibble marker by the nibble marker detector 1319, and the detection of the preformat information by the predata detector 1320 are also performed. It may be performed in units of. Therefore, it is preferable that the detection window generation unit 1324 generates such a detection window.
　尚、実質的には、検出ウインドウは、上述したマーク区間（つまり、情報用記録マークや判別用記録マークが形成される区間）に対応する長さを有するウインドウとなる。 In practice, the detection window is a window having a length corresponding to the above-described mark section (that is, a section in which an information recording mark or a discrimination recording mark is formed).
　タイミング生成部１３２５は、１ＥＣＣブロックのタイミングや、１グループのタイミングや、１スロットのタイミングや、１ウォブルのタイミング等を適宜生成する。タイミング生成部１３２５が生成したこれらのタイミングを参照することで、データ蓄積制御部１３２２や誤り訂正部１３２３は、ＥＣＣブロック、グループ、スロット及びウォブルのタイミングを認識する。 The timing generation unit 1325 appropriately generates 1 ECC block timing, 1 group timing, 1 slot timing, 1 wobble timing, and the like. By referring to these timings generated by the timing generation unit 1325, the data accumulation control unit 1322 and the error correction unit 1323 recognize the timing of the ECC block, group, slot, and wobble.
　（４－２）記録再生装置の動作の流れ
　続いて、図３１から図３７を参照して、本実施例の記録再生装置１００の動作の流れについて説明する。 (4-2) Operation Flow of Recording / Reproducing Device Next, with reference to FIGS. 31 to 37, the operation flow of the recording / reproducing device 100 of the present embodiment will be described.
　（４－２－１）動作の全体の流れ
　はじめに、図３１を参照して、本実施例の記録再生装置１００の動作の全体の流れについて説明する。図３１は、本実施例の記録再生装置１００の動作の全体の流れを示すフローチャートである。 (4-2-1) Overall Flow of Operation First, the overall flow of operation of the recording / reproducing apparatus 100 of the present embodiment will be described with reference to FIG. FIG. 31 is a flowchart showing an overall flow of the operation of the recording / reproducing apparatus 100 of the present embodiment.
　図３１に示すように、光ディスク１１が記録再生装置１００にローディングされると（ステップＳ１００）、光ピックアップ１０２からガイド層１２に対して、ガイドレーザ光ＬＢ１が照射される。このとき、トラッキング制御回路１２０は、ガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号に基づいて、ガイドレーザ光ＬＢ１のトラッキング制御を行う（ステップＳ１１０）。加えて、記録再生装置１００が備える不図示のフォーカス制御回路は、ガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号に基づいて、ガイドレーザ光ＬＢ１のフォーカス制御を行う（ステップＳ１１０）。 As shown in FIG. 31, when the optical disc 11 is loaded onto the recording / reproducing apparatus 100 (step S100), the guide laser beam LB1 is irradiated from the optical pickup 102 to the guide layer 12. At this time, the tracking control circuit 120 performs tracking control of the guide laser light LB1 based on the push-pull signal generated from the return light of the guide laser light LB1 (step S110). In addition, a focus control circuit (not shown) included in the recording / reproducing apparatus 100 performs focus control of the guide laser light LB1 based on a push-pull signal generated from the return light of the guide laser light LB1 (step S110).
　このとき、マーク群検出回路１３０は、ガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号に基づいて、ビットデータの検出を行ってもよい。その結果、ＣＰＵ１１１は、アドレス情報やクロック情報や記録開始タイミング情報等のプリフォーマット情報を取得することができる（ステップＳ１２０）。尚、記録再生装置１００が行うプリフォーマット情報の取得動作は、図３２から図３５を参照しながら後に詳述する。 At this time, the mark group detection circuit 130 may detect bit data based on a push-pull signal generated from the return light of the guide laser beam LB1. As a result, the CPU 111 can acquire preformat information such as address information, clock information, and recording start timing information (step S120). The preformat information acquisition operation performed by the recording / reproducing apparatus 100 will be described in detail later with reference to FIGS.
　その後、光ピックアップ１０２から複数の記録層１３のうちの所定の記録層１３に対して、記録再生レーザ光ＬＢ２が照射される。このとき、ＣＰＵ１１１は、マーク群検出回路１３０が検出したビットデータを組み合わせることで得られるアドレス情報を参照しながら、記録再生レーザ光ＬＢ２が所定の記録層１３上の適切な領域（より具体的には、後述するディスク管理情報が記録されている領域）に照射されるように、光ピックアップ１０２及び信号記録再生部１０３を制御する。その結果、ＣＰＵ１１１は、光ディスク１１上での記録態様を示すディスク管理情報（例えば、メディアIdentification情報、エリア管理情報等）を取得する（ステップＳ１３０）。 Thereafter, the recording / reproducing laser beam LB2 is irradiated from the optical pickup 102 to a predetermined recording layer 13 of the plurality of recording layers 13. At this time, the CPU 111 refers to the address information obtained by combining the bit data detected by the mark group detection circuit 130, and the recording / reproducing laser beam LB2 is applied to an appropriate region (more specifically, on the predetermined recording layer 13). Controls the optical pickup 102 and the signal recording / reproducing unit 103 so as to irradiate an area in which disc management information (to be described later) is recorded. As a result, the CPU 111 acquires disc management information (for example, media identification information, area management information, etc.) indicating the recording mode on the optical disc 11 (step S130).
　その後、ＣＰＵ１１１は、複数の記録層１３のうちの所望の記録層１３に対する記録動作が行われるか否かを判定する（ステップＳ１４０）。 Thereafter, the CPU 111 determines whether or not a recording operation is performed on a desired recording layer 13 among the plurality of recording layers 13 (step S140).
　ステップＳ１４０の判定の結果、所望の記録層１３に対する記録動作が行われると判定される場合には（ステップＳ１４０：Ｙｅｓ）、記録再生装置１００は、記録動作を行う（ステップＳ１５０）。尚、記録再生装置１００が行う記録動作は、図３６を参照しながら後に詳述する。 As a result of the determination in step S140, when it is determined that a recording operation on the desired recording layer 13 is performed (step S140: Yes), the recording / reproducing apparatus 100 performs a recording operation (step S150). The recording operation performed by the recording / reproducing apparatus 100 will be described in detail later with reference to FIG.
　他方で、ステップＳ１４０の判定の結果、所望の記録層１３に対する記録動作が行われないと判定される場合には（ステップＳ１４０：Ｎｏ）、ＣＰＵ１１１は、複数の記録層１３のうちの所望の記録層１３に対する再生動作が行われるか否かを判定する（ステップＳ１６０）。 On the other hand, as a result of the determination in step S140, when it is determined that the recording operation for the desired recording layer 13 is not performed (step S140: No), the CPU 111 determines the desired recording of the plurality of recording layers 13. It is determined whether or not the reproduction operation for the layer 13 is performed (step S160).
　ステップＳ１６０における判定の結果、所望の記録層１３に対する再生動作が行われると判定される場合には（ステップＳ１６０：Ｙｅｓ）、記録再生装置１００は、再生動作を行う（ステップＳ１７０）。尚、記録再生装置１００が行う再生動作は、図３７を参照しながら後に詳述する。 As a result of the determination in step S160, when it is determined that the reproduction operation for the desired recording layer 13 is performed (step S160: Yes), the recording / reproducing apparatus 100 performs the reproduction operation (step S170). The reproduction operation performed by the recording / reproducing apparatus 100 will be described in detail later with reference to FIG.
　他方で、ステップＳ１６０における判定の結果、所望の記録層１３に対する再生動作が行われないと判定される場合には（ステップＳ１６０：Ｎｏ）、記録再生装置１００は、動作を終了してもよい。 On the other hand, as a result of the determination in step S160, when it is determined that the reproduction operation for the desired recording layer 13 is not performed (step S160: No), the recording / reproducing apparatus 100 may end the operation.
　（４－２－２）プリフォーマット情報の取得動作
　続いて、図３２から図３５を参照して、本実施例の記録再生装置１００によるプリフォーマット情報の取得動作（図３１のステップＳ１２０）について説明を進める。 (4-2-2) Preformat Information Acquisition Operation Next, with reference to FIGS. 32 to 35, the preformat information acquisition operation (step S120 in FIG. 31) by the recording / reproducing apparatus 100 of the present embodiment will be described. To proceed.
　（４－２－２－１）プリフォーマット情報のデータ構造
　初めに、図３２及び図３３を参照しながら、プリフォーマット情報のデータ構造について説明する。図３２は、ＥＣＣブロックに含まれるスロット内でのビットデータのデータ構造を示すデータ構造図である。図３３は、ＥＣＣブロックに含まれる各ワードのプリフォーマット情報のデータ構造を示すデータ構造図である。 (4-2-2-1) Data Structure of Preformat Information First, the data structure of preformat information will be described with reference to FIG. 32 and FIG. FIG. 32 is a data structure diagram showing a data structure of bit data in a slot included in the ECC block. FIG. 33 is a data structure diagram showing a data structure of preformat information of each word included in the ECC block.
　上述したように、ガイド層１２上に記録されるプリフォーマット情報は、ＥＣＣブロックという単位で記録される。図１３では、ビットデータが、各スロットに３つ存在する例を示している。この場合、１つのスロットに含まれる３つのビットデータの構造は、図３２に示す３つの構造に分類される。 As described above, the preformat information recorded on the guide layer 12 is recorded in units of ECC blocks. FIG. 13 shows an example in which three bit data exist in each slot. In this case, the structure of the three bit data included in one slot is classified into the three structures shown in FIG.
　まず、３つのビットデータの第１の構造として、図３２の最上段のグラフに示すように、３つのビットデータの全てが、ＥＣＣブロックに含まれる各ワードの先頭部分であることを示すワードマーカとなる例がある。尚、図３２は、信号レベルが「０」、「＋」、「０」及び「－」と変化するプッシュプル信号がワードマーカに相当する例を示している。 First, as a first structure of three bit data, as shown in the uppermost graph of FIG. 32, a word marker indicating that all three bit data is the head portion of each word included in the ECC block. There is an example. FIG. 32 shows an example in which a push-pull signal whose signal level changes to “0”, “+”, “0”, and “−” corresponds to a word marker.
　３つのビットデータの第２の構造として、図３２の中段のグラフに示すように、３つのビットデータのうちの先頭の１つのビットデータが、後に続く４ビットのプリフォーマット情報の配列（このような配列を、“ニブル”と称している）の先頭であることを示すニブルマーカとなる一方で、３つのビットデータのうちの先頭以外の２つのビットデータが、プリフォーマット情報となる例がある。尚、図３２は、信号レベルが「０」、「－」、「０」及び「＋」と変化するプッシュプル信号がニブルマーカに相当する例を示している。 As the second structure of the three bit data, as shown in the middle graph of FIG. 32, the leading one bit data of the three bit data is followed by an array of 4-bit preformat information (such as this There is an example in which two bit data other than the head of the three bit data become the preformat information, while a nibble marker indicating that this is the head of “a nibble”). FIG. 32 shows an example in which a push-pull signal whose signal level changes to “0”, “−”, “0”, and “+” corresponds to a nibble marker.
　３つのビットデータの第３の構造として、図３２の下段段のグラフに示すように、３つのビットデータの全てが、プリフォーマット情報となる例がある。尚、プリフォーマット情報は、上述したビットデータ（ビット０）又はビットデータ（ビット１）に相当する。 As a third structure of the three bit data, there is an example in which all of the three bit data becomes preformat information as shown in the lower graph of FIG. The preformat information corresponds to the bit data (bit 0) or bit data (bit 1) described above.
　図３２の最上段に示すワードマーカを含むビットデータは、各ワードの最初のグループの全てのスロットに割り当てられる。つまり、１つのＥＣＣブロックに着目すれば、ワード＃１のグループ＃１に含まれるスロット＃１からスロット＃８は全て、図３２の最上部に示すデータ構造を有している。同様に、１つのＥＣＣブロックに着目すれば、ワード＃２のグループ＃４１に含まれるスロット＃１からスロット＃８は全て、図３２の最上段に示すデータ構造を有している。 32. Bit data including the word marker shown at the top of FIG. 32 is assigned to all slots of the first group of each word. In other words, focusing on one ECC block, all slots # 1 to # 8 included in group # 1 of word # 1 have the data structure shown at the top of FIG. Similarly, if attention is paid to one ECC block, all of the slots # 1 to # 8 included in the group # 41 of the word # 2 have the data structure shown in the uppermost stage of FIG.
　一方で、図３２の中段に示すニブルマーカを含むビットデータ及び図３２の最下段に示すプリフォーマット情報のみを含むビットデータは、各ワードの最初のグループ以外の他のグループの各スロットに交互に割り当てられる。例えば、１つのＥＣＣブロックに着目すれば、ワード＃１のグループ＃２からグループ＃４０の夫々のスロット＃１、スロット＃３、スロット＃５及びスロット＃７が、図３２の中段に示すデータ構造を有している一方で、ワード＃１のグループ＃２からグループ＃４０の夫々のスロット＃２、スロット＃４、スロット＃６及びスロット＃８が、図３２の最下段に示すデータ構造を有していてもよい。 On the other hand, the bit data including the nibble marker shown in the middle of FIG. 32 and the bit data including only the preformat information shown in the bottom of FIG. It is done. For example, focusing on one ECC block, the slot # 1, slot # 3, slot # 5, and slot # 7 of the group # 2 to the group # 40 of the word # 1 have the data structure shown in the middle of FIG. On the other hand, slot # 2, slot # 4, slot # 6 and slot # 8 of group # 2 to group # 40 of word # 1 have the data structure shown at the bottom of FIG. You may do it.
　このようなプリフォーマット情報が９０ビット集められる（つまり、１ワード分のプリフォーマット情報が集められる）ことで、図３３に示すように、１ＥＣＣブロックのプリフォーマット情報（例えば、当該ＥＣＣブロックのアドレス情報等）が得られる。つまり、プリデータ検出器１３２０によって検出されたプリフォーマット情報をワードマーカが検出された時点を基準としてビット１から順番に保存することで、図３３に示す１ＥＣＣブロックのプリフォーマット情報が得られる。このとき、図３３に示すように、プリフォーマット情報は、ビットｋ（但し、ｋは、１≦ｋ≦８を満たす整数）からビットｋ＋３及びビットｋ＋５からビットｋ＋８が有効なデータを示す一方で、ビットｋ＋４及びビットｋ＋９がパリティを示す。 By collecting 90 bits of such preformat information (that is, collecting preformat information for one word), as shown in FIG. 33, preformat information of one ECC block (for example, address information of the ECC block). Etc.) is obtained. That is, the preformat information of one ECC block shown in FIG. 33 is obtained by storing the preformat information detected by the predata detector 1320 in order from bit 1 with reference to the time point when the word marker is detected. At this time, as shown in FIG. 33, the preformat information indicates valid data from bit k (where k is an integer satisfying 1 ≦ k ≦ 8) to bit k + 3 and bit k + 5 to bit k + 8. Bit k + 4 and bit k + 9 indicate parity.
　（４－２－２－２）プリフォーマット情報の取得動作の流れ
　続いて、図３４から図３５を参照しながら、本実施例の記録再生装置１００のプリフォーマット情報の取得動作（図３１のステップＳ１２０）の流れについて説明する。図３４は、本実施例の記録再生装置１００の記録動作（図３１のステップＳ１２０）の流れを示すフローチャートである。図３５は、トラック番号がｋとなるグルーブトラックＧＴ（ｋ）がセンタートラックＣＴであると判定される場合に読み取られる情報用マーク群ＭＧ１を示す平面図である。 (4-2-2) Preformat Information Acquisition Operation Flow Next, with reference to FIGS. 34 to 35, the preformat information acquisition operation of the recording / reproducing apparatus 100 of the present embodiment (step of FIG. 31). The flow of S120) will be described. FIG. 34 is a flowchart showing the flow of the recording operation (step S120 in FIG. 31) of the recording / reproducing apparatus 100 of the present embodiment. FIG. 35 is a plan view showing the information mark group MG1 that is read when it is determined that the groove track GT (k) with the track number k is the center track CT.
　図３４に示すように、同期データ検出器１３１６は、比較器１３１５における比較結果に基づいて、同期データが検出されたか否かを判定する（ステップＳ１２１１）。 34, the synchronization data detector 1316 determines whether or not synchronization data has been detected based on the comparison result in the comparator 1315 (step S1211).
　ステップＳ１２１１の判定の結果、同期データが検出されていないと判定される場合には（ステップＳ１２１１：Ｎｏ）、同期データ検出器１３１６は、同期データが検出されたか否かを再度判定する。 If it is determined that the synchronization data is not detected as a result of the determination in step S1211 (step S1211: No), the synchronization data detector 1316 determines again whether the synchronization data is detected.
　他方で、ステップＳ１２１１の判定の結果、同期データが検出されたと判定される場合には（ステップＳ１２１１：Ｙｅｓ）、続いて、判別マーク群検出器１３１７は、比較器１３１５における比較結果（特に、判別マーク群ＭＧ２に対応するプッシュプル信号の信号レベルと第１及び第２閾値との比較結果）に基づいて、ガイドレーザ光ＬＢ１がトレースしているガイドトラックＴＲがセンタートラックＣＴであるか否かを判定する（ステップＳ１２１２）。尚、ガイドレーザ光ＬＢ１がトレースしているガイドトラックＴＲがセンタートラックＣＴであるか否かの判定動作については、上述したとおりである（図７から図１２参照）。 On the other hand, if it is determined that the synchronization data has been detected as a result of the determination in step S1211 (step S1211: Yes), the determination mark group detector 1317 then determines the comparison result (particularly, the determination) in the comparator 1315. Based on the comparison result between the signal level of the push-pull signal corresponding to the mark group MG2 and the first and second threshold values), it is determined whether or not the guide track TR traced by the guide laser beam LB1 is the center track CT. Determination is made (step S1212). The operation for determining whether or not the guide track TR traced by the guide laser beam LB1 is the center track CT is as described above (see FIGS. 7 to 12).
　ステップＳ１２１２の判定の結果、ガイドレーザ光ＬＢ１がトレースしているガイドトラックＴＲがセンタートラックＣＴでないと判定される場合は（ステップＳ１２１２：Ｎｏ）、ステップＳ１２１１以降の動作が繰り返される。つまり、同期データ検出器１３１６は、同期データが検出されたか否かを再度判定する。 As a result of the determination in step S1212, when it is determined that the guide track TR traced by the guide laser beam LB1 is not the center track CT (step S1212: No), the operations after step S1211 are repeated. That is, the synchronization data detector 1316 determines again whether synchronization data has been detected.
　他方で、ステップＳ１２１２の判定の結果、ガイドレーザ光ＬＢ１がトレースしているガイドトラックＴＲがセンタートラックＣＴであると判定される場合は（ステップＳ１２１２：Ｙｅｓ）、ワードマーカ検出器１３１８は、比較器１３１５における比較結果に基づいて、ビットデータの一例であるワードマーカが検出されたか否かを判定する（ステップＳ１２１３）。つまり、ワードマーカ検出器１３１８は、判別用マーク群ＭＧ２に応じたプッシュプル信号が検出された直後に、ワードマーカに相当する態様で信号レベルが変動するプッシュプル信号が検出されたか否かを判定する。 On the other hand, if it is determined as a result of the determination in step S1212 that the guide track TR traced by the guide laser beam LB1 is the center track CT (step S1212: Yes), the word marker detector 1318 includes a comparator. Based on the comparison result in 1315, it is determined whether or not a word marker, which is an example of bit data, has been detected (step S1213). That is, the word marker detector 1318 determines whether or not a push-pull signal whose signal level fluctuates in a manner corresponding to the word marker is detected immediately after the push-pull signal corresponding to the discrimination mark group MG2 is detected. To do.
　ステップＳ１２１３の判定の結果、ワードマーカが検出されていないと判定される場合は（ステップＳ１２１３：Ｎｏ）、ステップＳ１２１１以降の動作が繰り返される。つまり、同期データ検出器１３１６は、同期データが検出されたか否かを再度判定する。 If it is determined that the word marker is not detected as a result of the determination in step S1213 (step S1213: No), the operations after step S1211 are repeated. That is, the synchronization data detector 1316 determines again whether synchronization data has been detected.
　他方で、ステップＳ１２１３の判定の結果、ワードマーカが検出されたと判定される場合は（ステップＳ１２１３：Ｙｅｓ）、ワードの先頭が検出されたがゆえに、今からプリフォーマット情報がビットデータとして検出されることが予想される。つまり、以降、図３２の中段のデータ構造を有するスロット及び図３２の最下段のデータ構造を有するスロットが、１ワード分検出されると想定される。 On the other hand, if it is determined that the word marker is detected as a result of the determination in step S1213 (step S1213: Yes), the preformat information is detected as bit data from now because the head of the word is detected. It is expected that. In other words, it is assumed that a slot having the middle data structure in FIG. 32 and a slot having the lowermost data structure in FIG. 32 are detected for one word.
　このため、この場合には、同期データ検出器１３１６による同期データの検出（ステップＳ１２１４）及び判別マーク群検出器１３１７によるセンタートラックＣＴの判定（ステップＳ１２１５）が改めて行われる。尚、ステップＳ１２１４の同期データの検出動作は、ステップＳ１２１１の同期データの検出動作と同一である。また、ステップＳ１２１５のセンタートラックＣＴの判定動作は、ステップＳ１２１２のセンタートラックＣＴの判定動作と同一である。 For this reason, in this case, detection of the synchronization data by the synchronization data detector 1316 (step S1214) and determination of the center track CT by the discrimination mark group detector 1317 (step S1215) are performed again. The synchronous data detection operation in step S1214 is the same as the synchronous data detection operation in step S1211. Further, the operation for determining the center track CT in step S1215 is the same as the operation for determining the center track CT in step S1212.
　ステップＳ１２１４及びステップＳ１２１５の判定の結果、同期データが検出されていない又はガイドレーザ光ＬＢ１がトレースしているガイドトラックＴＲがセンタートラックＣＴでないと判定される場合には（ステップＳ１２１４：Ｎｏ又はステップＳ１２１５：Ｎｏ）、ステップＳ１２１４以降の動作が繰り返される。つまり、同期データ検出器１３１６は、同期データが検出されたか否かを再度判定する。 As a result of the determination in step S1214 and step S1215, when it is determined that the synchronization data is not detected or the guide track TR traced by the guide laser beam LB1 is not the center track CT (step S1214: No or step S1215). : No), the operation after step S1214 is repeated. That is, the synchronization data detector 1316 determines again whether synchronization data has been detected.
　他方で、ステップＳ１２１４及びステップＳ１２１５の判定の結果、同期データが検出され且つガイドレーザ光ＬＢ１がトレースしているガイドトラックＴＲがセンタートラックＣＴであると判定される場合には（ステップＳ１２１４：Ｙｅｓ且つステップＳ１２１５：Ｙｅｓ）、ニブルマーカ検出器１３１９は、比較器１３１５における比較結果に基づいて、ビットデータの一例であるニブルマーカが検出されたか否かを判定する（ステップＳ１２１６）。つまり、ニブルマーカ検出器１３１９は、判別用マーク群ＭＧ２に応じたプッシュプル信号が検出された直後に、ニブルマーカに相当する態様で信号レベルが変動するプッシュプル信号が検出されたか否かを判定する。 On the other hand, as a result of the determination in step S1214 and step S1215, when it is determined that the synchronization data is detected and the guide track TR traced by the guide laser beam LB1 is the center track CT (step S1214: Yes and In step S1215: Yes, the nibble marker detector 1319 determines whether a nibble marker, which is an example of bit data, is detected based on the comparison result in the comparator 1315 (step S1216). That is, the nibble marker detector 1319 determines whether or not a push-pull signal whose signal level varies in a manner corresponding to the nibble marker is detected immediately after the push-pull signal corresponding to the discrimination mark group MG2 is detected.
　ステップＳ１２１６の判定の結果、ニブルマーカが検出されたと判定される場合は（ステップＳ１２１６：Ｙｅｓ）、図３２の中段のデータ構造を有するスロットが検出されたものと推測される。従って、この場合には、プリデータ検出器１３２０は、比較器１３１５における比較結果に基づいて、ニブルマーカに続いて現れる２ビットのプリフォーマット情報を検出する（ステップＳ１２１７）。２ビットのプリフォーマット情報は、バッファメモリ１３２１に保存される（ステップＳ１２１７）。 If it is determined that the nibble marker has been detected as a result of the determination in step S1216 (step S1216: Yes), it is estimated that a slot having the middle data structure in FIG. 32 has been detected. Accordingly, in this case, the pre-data detector 1320 detects 2-bit pre-format information that appears following the nibble marker based on the comparison result in the comparator 1315 (step S1217). The 2-bit preformat information is stored in the buffer memory 1321 (step S1217).
　他方で、ステップＳ１２１６の判定の結果、ニブルマーカが検出されていないと判定される場合は（ステップＳ１２１６：Ｎｏ）、図３２の最下段のデータ構造を有するスロットが検出されたものと推測される。従って、この場合には、プリデータ検出器１３２０は、比較器１３１５における比較結果に基づいて、判別用マーク群ＭＧ２に続いて現れる３ビットのプリフォーマット情報を検出する（ステップＳ１２１８）。３ビットのプリフォーマット情報は、バッファメモリ１３２１に保存される（ステップＳ１２１８）。 On the other hand, if it is determined that the nibble marker has not been detected as a result of the determination in step S1216 (step S1216: No), it is presumed that the slot having the lowermost data structure in FIG. 32 has been detected. Accordingly, in this case, the pre-data detector 1320 detects 3-bit pre-format information that appears following the discrimination mark group MG2 based on the comparison result in the comparator 1315 (step S1218). The 3-bit preformat information is stored in the buffer memory 1321 (step S1218).
　その後、データ蓄積制御部１３２２は、９０ビットのプリフォーマット情報（つまり、１ワード分のプリフォーマット情報）がバッファメモリ１３２１に保存されたか否かを判定する（ステップＳ１２１９）。 Thereafter, the data accumulation control unit 1322 determines whether 90-bit preformat information (that is, preformat information for one word) is stored in the buffer memory 1321 (step S1219).
　ステップＳ１２１９の判定の結果、９０ビットのプリフォーマット情報が保存されていないと判定される場合には（ステップＳ１２１９：Ｎｏ）、ステップＳ１２１４以降の動作が繰り返される。つまり、同期データ検出器１３１６は、同期データが検出されたか否かを再度判定する。 If it is determined that the 90-bit preformat information is not stored as a result of the determination in step S1219 (step S1219: No), the operations after step S1214 are repeated. That is, the synchronization data detector 1316 determines again whether synchronization data has been detected.
　他方で、ステップＳ１２１９の判定の結果、９０ビットのプリフォーマット情報が保存されたと判定される場合には（ステップＳ１２１９：Ｙｅｓ）、誤り訂正部１３２３は、９０ビットのプリフォーマット情報（つまり、１ワードの（言い換えれば、１ＥＣＣブロックの）プリフォーマット情報）に対して誤り訂正処理を行う（ステップＳ１２２０）。その後、誤り訂正処理が行われた１ＥＣＣブロックのプリフォーマット情報（例えば、当該ＥＣＣブロックのアドレス情報等）は、記録動作及び再生動作の際に参照されるべく、ＣＰＵ１１１へと転送される。 On the other hand, as a result of the determination in step S1219, when it is determined that 90-bit preformat information is stored (step S1219: Yes), the error correction unit 1323 determines that the 90-bit preformat information (that is, one word) (In other words, preformat information of one ECC block) is subjected to error correction processing (step S1220). Thereafter, preformat information (for example, address information of the ECC block) of one ECC block on which error correction processing has been performed is transferred to the CPU 111 so that it can be referred to during recording and reproduction operations.
　このように、本実施例では、ガイドレーザ光ＬＢ１がトレースしているガイドトラックＴＲがセンタートラックＣＴであると判別マーク群検出器１３１７によって判定された場合に、プリフォーマット情報の検出及び保存が行われる。ここで、より明瞭な説明のために、図３５に示すように、トラック番号が「ｋ」となるグルーブトラックＧＴ（ｋ）をトレースしている場合を例に挙げて説明する。この場合、トラック番号が「ｋ」となるグルーブトラックＧＴ（ｋ）がセンタートラックＣＴとなるため、グループ＃ｊのスロット＃１をトレースしている場合及びグループ＃ｊ＋１のスロット＃１をトレースしている場合には、情報用マーク群ＭＧ１（図３５中で黒塗りの情報用マーク群ＭＧ１（ｋ））に応じたプリフォーマット情報の検出及び保存が行われる。 As described above, in this embodiment, when the determination mark group detector 1317 determines that the guide track TR traced by the guide laser beam LB1 is the center track CT, the preformat information is detected and stored. Is called. Here, for clearer explanation, a case where a groove track GT (k) having a track number “k” is traced as shown in FIG. 35 will be described as an example. In this case, since the groove track GT (k) with the track number “k” is the center track CT, when tracing the slot # 1 of the group #j and when tracing the slot # 1 of the group # j + 1 If so, preformat information is detected and stored in accordance with the information mark group MG1 (black information mark group MG1 (k) in FIG. 35).
　一方で、トラック番号が「ｋ」となるグルーブトラックＧＴ（ｋ）をトレースしているガイドレーザ光ＬＢ１の戻り光から取得されるプッシュプル信号には、図３５中にハッチングで示されているグループ＃ｊのスロット＃２に形成される情報用マーク群ＭＧ１（ｋ＋１）に応じた信号レベルの変動が含まれる。しかしながら、グループ＃ｊのスロット＃２に形成される情報用マーク群ＭＧ１（ｋ＋１）からは、同期データは検出されるものの、センタートラックＣＴではないことを示す判別用マーク群ＭＧ２が検出される。というのも、グループ＃ｊのスロット＃２に形成される情報用マーク群ＭＧ１（ｋ＋１）にとってのセンタートラックＣＴ（つまり、グループ＃ｊのスロット＃２におけるセンタートラックＣＴ）は、ガイドレーザ光ＬＢ１が現在トレースしているトラック番号が「ｋ」となるグルーブトラックＧＴ（ｋ）ではなく、トラック番号が「ｋ＋１」となるランドトラックＬＴ（ｋ＋１）だからである。このため、グループ＃ｊのスロット＃２に形成される情報用マーク群ＭＧ１（ｋ＋１）に応じたプリフォーマット情報の検出及び保存は行われない。グループ＃ｊのスロット＃３に形成される情報用マーク群ＭＧ１（ｋ＋２）や、グループ＃ｊのスロット＃４に形成される情報用マーク群ＭＧ１（ｋ＋３）や、グループ＃ｊのスロット＃５に形成される情報用マーク群ＭＧ１（ｋ＋４）や、グループ＃ｊのスロット＃８に形成される情報用マーク群ＭＧ１（ｋ－１）や、グループ＃ｊ＋１のスロット＃２に形成される情報用マーク群ＭＧ１（ｋ＋１）や、グループ＃ｊ＋１のスロット＃３に形成される情報用マーク群ＭＧ１（ｋ＋２）や、グループ＃ｊ＋１のスロット＃４に形成される情報用マーク群ＭＧ１（ｋ＋３）や、グループ＃ｊ＋１のスロット＃５に形成される情報用マーク群ＭＧ１（ｋ＋４）や、グループ＃ｊ＋１のスロット＃８に形成される情報用マーク群ＭＧ１（ｋ－１）についても同様である。 On the other hand, the push-pull signal acquired from the return light of the guide laser beam LB1 tracing the groove track GT (k) with the track number “k” is indicated by hatching in FIG. The fluctuation of the signal level according to the information mark group MG1 (k + 1) formed in the slot # 2 of #j is included. However, from the information mark group MG1 (k + 1) formed in the slot # 2 of the group #j, the discrimination mark group MG2 indicating that it is not the center track CT is detected although the synchronization data is detected. This is because the center track CT for the information mark group MG1 (k + 1) formed in the slot # 2 of the group #j (that is, the center track CT in the slot # 2 of the group #j) is the guide laser beam LB1. This is because the land track LT (k + 1) with the track number “k + 1” is not the groove track GT (k) with the track number currently being traced “k”. For this reason, detection and storage of preformat information according to the information mark group MG1 (k + 1) formed in the slot # 2 of the group #j is not performed. Information mark group MG1 (k + 2) formed in slot # 3 of group #j, information mark group MG1 (k + 3) formed in slot # 4 of group #j, and slot # 5 of group #j Information mark group MG1 (k + 4) to be formed, information mark group MG1 (k-1) formed in slot # 8 of group #j, and information mark formed in slot # 2 of group # j + 1 Group MG1 (k + 1), information mark group MG1 (k + 2) formed in slot # 3 of group # j + 1, information mark group MG1 (k + 3) formed in slot # 4 of group # j + 1, group Information mark group MG1 (k + 4) formed in slot # 5 of # j + 1 and information mark group MG1 (k-1) formed in slot # 8 of group # j + 1. Stomach is the same.
　（４－２－３）記録動作の流れ
　続いて、図３６を参照して、本実施例の記録再生装置１００の記録動作（図３１のステップＳ１５０）の流れについて説明する。図３６は、本実施例の記録再生装置１００の記録動作（図３１のステップＳ１５０）の流れを示すフローチャートである。 (4-2-3) Flow of Recording Operation Next, with reference to FIG. 36, the flow of the recording operation (step S150 in FIG. 31) of the recording / reproducing apparatus 100 of the present embodiment will be described. FIG. 36 is a flowchart showing the flow of the recording operation (step S150 in FIG. 31) of the recording / reproducing apparatus 100 of the present embodiment.
　尚、記録再生装置１００は、記録動作を行う際にも、アドレス情報やクロック情報や記録開始タイミング情報を含むプリフォーマット情報を参照することが好ましい。従って、記録再生装置１００は、図３０に示す記録動作を行う際にも、適宜プリフォーマット情報の取得動作（図３１のステップＳ１２０参照）を行っている。 The recording / reproducing apparatus 100 preferably refers to preformat information including address information, clock information, and recording start timing information when performing a recording operation. Therefore, the recording / reproducing apparatus 100 appropriately performs the preformat information acquisition operation (see step S120 in FIG. 31) when performing the recording operation shown in FIG.
　図３６に示すように、ＣＰＵ１１１は、所望のアドレス情報が示すガイド層１２上の領域に対してガイドレーザ光ＬＢ１が照射されるように、光ピックアップ１０２及び信号記録再生部１０３を制御する（ステップＳ１５１）。このとき、ＣＰＵ１１１は、マーク群検出回路１３０が検出したビットデータを組み合わせることで得られるアドレス情報を参照しながら、光ピックアップ１０２及び信号記録再生部１０３を制御する。尚、ここでの「所望のアドレス情報」とは、例えば、記録動作を開始したい領域のアドレス情報が一例となる。 As shown in FIG. 36, the CPU 111 controls the optical pickup 102 and the signal recording / reproducing unit 103 so that the guide laser beam LB1 is irradiated onto the area on the guide layer 12 indicated by the desired address information (step). S151). At this time, the CPU 111 controls the optical pickup 102 and the signal recording / reproducing unit 103 while referring to address information obtained by combining the bit data detected by the mark group detection circuit 130. The “desired address information” here is, for example, address information of an area where a recording operation is to be started.
　所望のアドレス情報が示すガイド層１２上の領域に対してガイドレーザ光ＬＢ１が照射された時点で、ＣＰＵ１１１は、所望の記録層１３に対して記録再生レーザ光ＬＢ２のフォーカスが合わせられるように、記録再生レーザ光ＬＢ２の戻り光から生成されるプッシュプル信号に基づいて、記録再生レーザ光ＬＢ２のフォーカス制御を行う（ステップＳ１５２）。 When the guide laser beam LB1 is irradiated to the area on the guide layer 12 indicated by the desired address information, the CPU 111 adjusts the focus of the recording / reproducing laser beam LB2 to the desired recording layer 13. Based on the push-pull signal generated from the return light of the recording / reproducing laser beam LB2, focus control of the recording / reproducing laser beam LB2 is performed (step S152).
　更に、ＣＰＵ１１１は、ガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号に基づいて、ガイドレーザ光ＬＢ１のトラッキング制御を行う（ステップＳ１５３）。 Further, the CPU 111 performs tracking control of the guide laser beam LB1 based on the push-pull signal generated from the return light of the guide laser beam LB1 (step S153).
　更に、ＣＰＵ１１１は、マーク群検出回路１３０が検出したビットデータを組み合わせることで得られるアドレス情報や、クロック情報及び記録開始タイミング情報を取得する（ステップＳ１５４）。 Further, the CPU 111 acquires address information, clock information, and recording start timing information obtained by combining the bit data detected by the mark group detection circuit 130 (step S154).
　その後、ＣＰＵ１１１は、現在のタイミングが、ステップＳ１５４において取得した記録開始タイミング情報と一致するか否かを判定する（ステップＳ１５５）。 After that, the CPU 111 determines whether or not the current timing matches the recording start timing information acquired in step S154 (step S155).
　ステップＳ１５５の判定の結果、現在のタイミングが記録開始タイミング情報と一致しないと判定される場合には（ステップＳ１５５：Ｎｏ）、ＣＰＵ１１１は、ステップＳ１５５の判定を継続する。 As a result of the determination in step S155, when it is determined that the current timing does not match the recording start timing information (step S155: No), the CPU 111 continues the determination in step S155.
　他方で、ステップＳ１５５の判定の結果、現在のタイミングが記録開始タイミング情報と一致すると判定される場合には（ステップＳ１５５：Ｙｅｓ）、ＣＰＵ１１１は、ステップＳ１５４において取得したクロック情報に同期して、所望の記録層１３に対する記録動作を行うように光ピックアップ１０２及び信号記録再生部１０３を制御する（ステップＳ１５６）。その結果、記録情報が所望の記録層１３に記録される。 On the other hand, as a result of the determination in step S155, if it is determined that the current timing coincides with the recording start timing information (step S155: Yes), the CPU 111 synchronizes with the clock information acquired in step S154, and selects the desired timing. The optical pickup 102 and the signal recording / reproducing unit 103 are controlled so as to perform the recording operation on the recording layer 13 (step S156). As a result, the record information is recorded on the desired recording layer 13.
　その後、ＣＰＵ１１１は、記録動作を終了するか否かを判定する（ステップＳ１５７）。例えば、ＣＰＵ１１１は、所定サイズの記録情報或いは今回の記録動作で記録するべき記録情報の記録が完了した場合には、記録動作を終了すると判定してもよい。 Thereafter, the CPU 111 determines whether or not to end the recording operation (step S157). For example, the CPU 111 may determine to end the recording operation when recording of recording information of a predetermined size or recording information to be recorded in the current recording operation is completed.
　ステップＳ１５７の判定の結果、記録動作を終了しないと判定される場合には（ステップＳ１５７：Ｎｏ）、ＣＰＵ１１１は、記録動作を継続する。 As a result of the determination in step S157, if it is determined not to end the recording operation (step S157: No), the CPU 111 continues the recording operation.
　他方で、ステップＳ１５７の判定の結果、記録動作を終了すると判定される場合には（ステップＳ１５７：Ｙｅｓ）、ＣＰＵ１１１は、今回の記録動作を反映するように管理情報を更新する。その後、記録再生装置１００は、記録動作を終了する。 On the other hand, if it is determined that the recording operation is to be ended as a result of the determination in step S157 (step S157: Yes), the CPU 111 updates the management information to reflect the current recording operation. Thereafter, the recording / reproducing apparatus 100 ends the recording operation.
　（４－２－４）再生動作の流れ
　続いて、図３７を参照して、本実施例の記録再生装置１００の再生動作（図３１のステップＳ１７０）の流れについて説明する。図３７は、本実施例の記録再生装置１００の再生動作（図３１のステップＳ１７０）の流れを示すフローチャートである。 (4-2-4) Flow of Reproducing Operation Next, with reference to FIG. 37, the flow of the reproducing operation (step S170 in FIG. 31) of the recording / reproducing apparatus 100 of the present embodiment will be described. FIG. 37 is a flowchart showing the flow of the reproducing operation (step S170 in FIG. 31) of the recording / reproducing apparatus 100 of the present embodiment.
　尚、記録再生装置１００は、再生動作を行う際にも、アドレス情報やクロック情報や記録開始タイミング情報を含むプリフォーマット情報を参照することが好ましい。従って、記録再生装置１００は、図３７に示す再生動作を行う際にも、適宜プリフォーマット情報の取得動作（図３１のステップＳ１２０参照）を行っている。 Note that the recording / reproducing apparatus 100 preferably refers to preformat information including address information, clock information, and recording start timing information when performing a reproducing operation. Therefore, the recording / reproducing apparatus 100 appropriately performs the preformat information acquisition operation (see step S120 in FIG. 31) even when performing the reproduction operation shown in FIG.
　図３７に示すように、ＣＰＵ１１１は、所望のアドレス情報が示すガイド層１２上の領域に対してガイドレーザ光ＬＢ１が照射されるように、光ピックアップ１０２及び信号記録再生部１０３を制御する（ステップＳ１７１）。このとき、ＣＰＵ１１１は、マーク群検出回路１３０が検出したビットデータを組み合わせることで得られるアドレス情報を参照しながら、光ピックアップ１０２及び信号記録再生部１０３を制御する。このため、記録再生装置１００は、ステップＳ１７１の動作を行う際にも、適宜プリフォーマット情報の取得動作（図３１のステップＳ１２０参照）を行っている。尚、ここでの「所望のアドレス情報」とは、例えば、再生動作を開始したい領域のアドレス情報が一例となる。 As shown in FIG. 37, the CPU 111 controls the optical pickup 102 and the signal recording / reproducing unit 103 so that the guide laser beam LB1 is irradiated to the area on the guide layer 12 indicated by the desired address information (step). S171). At this time, the CPU 111 controls the optical pickup 102 and the signal recording / reproducing unit 103 while referring to address information obtained by combining the bit data detected by the mark group detection circuit 130. Therefore, the recording / reproducing apparatus 100 appropriately performs the preformat information acquisition operation (see step S120 in FIG. 31) when performing the operation in step S171. The “desired address information” here is, for example, address information of an area where a reproduction operation is to be started.
　所望のアドレス情報が示すガイド層１２上の領域に対してガイドレーザ光ＬＢ１が照射された時点で、ＣＰＵ１１１は、所望の記録層１３に対して記録再生レーザ光ＬＢ２のフォーカスが合わせられるように、記録再生レーザ光ＬＢ２の戻り光から生成されるプッシュプル信号に基づいて、記録再生レーザ光ＬＢ２のフォーカス制御を行う（ステップＳ１７２）。 When the guide laser beam LB1 is irradiated to the area on the guide layer 12 indicated by the desired address information, the CPU 111 adjusts the focus of the recording / reproducing laser beam LB2 to the desired recording layer 13. Based on the push-pull signal generated from the return light of the recording / reproducing laser beam LB2, focus control of the recording / reproducing laser beam LB2 is performed (step S172).
　更に、ＣＰＵ１１１は、所望の記録層１３に記録された記録情報を示す記録マークに記録再生レーザ光ＬＢ２が照射されるように、記録再生レーザ光ＬＢ２の戻り光から生成されるプッシュプル信号に基づいて、記録再生レーザ光ＬＢ２のトラッキング制御を行う（ステップＳ１７３）。但し、上述したように、ガイドレーザ光ＬＢ１の戻り光から生成されるプッシュプル信号に基づいてガイドレーザ光ＬＢ１のトラッキング制御を行うことで、実質的に記録再生レーザ光ＬＢ２のトラッキング制御を行ってもよい。 Further, the CPU 111 is based on the push-pull signal generated from the return light of the recording / reproducing laser beam LB2 so that the recording mark indicating the recording information recorded on the desired recording layer 13 is irradiated with the recording / reproducing laser beam LB2. Then, tracking control of the recording / reproducing laser beam LB2 is performed (step S173). However, as described above, the tracking control of the recording / reproducing laser beam LB2 is substantially performed by performing the tracking control of the guide laser beam LB1 based on the push-pull signal generated from the return light of the guide laser beam LB1. Also good.
　その後、ＣＰＵ１１１は、所望の記録層１３に対する再生動作を行うように光ピックアップ１０２及び信号記録再生部１０３を制御する（ステップＳ１７６）。その結果、所望の記録層１３に記録された記録情報が再生される。 Thereafter, the CPU 111 controls the optical pickup 102 and the signal recording / reproducing unit 103 so as to perform a reproducing operation on the desired recording layer 13 (step S176). As a result, the recorded information recorded on the desired recording layer 13 is reproduced.
　その後、ＣＰＵ１１１は、記録動作を終了するか否かを判定する（ステップＳ１７７）。例えば、ＣＰＵ１１１は、所定サイズの記録情報或いは今回の再生動作で再生するべき記録情報の再生が完了した場合には、再生動作を終了すると判定してもよい。 Thereafter, the CPU 111 determines whether or not to end the recording operation (step S177). For example, the CPU 111 may determine to end the reproduction operation when the reproduction of the recording information of a predetermined size or the recording information to be reproduced in the current reproduction operation is completed.
　ステップＳ１７７の判定の結果、再生動作を終了しないと判定される場合には（ステップＳ１７７：Ｎｏ）、ＣＰＵ１１１は、再生動作を継続する。 As a result of the determination in step S177, when it is determined not to end the reproduction operation (step S177: No), the CPU 111 continues the reproduction operation.
　他方で、ステップＳ１７７の判定の結果、再生動作を終了すると判定される場合には（ステップＳ１７７：Ｙｅｓ）、記録再生装置１００は、再生動作を終了する。 On the other hand, as a result of the determination in step S177, when it is determined that the reproduction operation is to be ended (step S177: Yes), the recording / reproducing apparatus 100 ends the reproduction operation.
　以上説明したように、本実施例の記録再生装置１００は、上述した本実施例の光ディスク１１に対する記録動作及び再生動作を好適に行うことができる。このため、本実施例の記録再生装置１００は、上述した本実施例の光ディスク１１が享受する各種効果と同様の効果を享受しながら、光ディスク１１に対する記録動作及び再生動作を好適に行うことができる。 As described above, the recording / reproducing apparatus 100 according to the present embodiment can suitably perform the recording operation and the reproducing operation with respect to the optical disc 11 according to the above-described embodiment. For this reason, the recording / reproducing apparatus 100 of a present Example can perform suitably the recording operation and reproduction | regeneration operation | movement with respect to the optical disk 11, enjoying the effect similar to the various effects which the optical disk 11 of a present Example mentioned above enjoys. .
　尚、上述の説明では、記録再生装置１００が記録動作及び再生動作の双方を行う例を説明している。しかしながら、記録再生装置１００は、記録動作のみを行ってもよい（つまり、再生動作を行わなくともよい）し、再生動作のみを行ってもよい（つまり、記録動作を行わなくともよい）。 In the above description, an example in which the recording / reproducing apparatus 100 performs both the recording operation and the reproducing operation has been described. However, the recording / reproducing apparatus 100 may perform only the recording operation (that is, the reproduction operation may not be performed) or may perform only the reproduction operation (that is, the recording operation may not be performed).
　また、本発明は、請求の範囲及び明細書全体から読み取るこのできる発明の要旨又は思想に反しない範囲で適宜変更可能であり、そのような変更を伴う記録再生装置及び方法もまた本発明の技術思想に含まれる。 Further, the present invention can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and a recording / reproducing apparatus and method involving such a change are also applicable to the technology of the present invention. Included in thought.
　１１　光ディスク
　１２　ガイド層
　１３　記録層
　１００　記録再生装置
　１０２　光ピックアップ
　１０３　信号記録再生部
　１１１　ＣＰＵ
　１２０　トラッキング制御回路
　１３０　マーク群検出回路
　１３１５　比較器
　１３１６　同期データ検出器
　１３２０　プリデータ検出器
　ＴＲ　ガイドトラック
　ＧＴ　グルーブトラック
　ＬＴ　ランドトラック
　ＣＴ　センタートラック
　ＭＧ１　情報用マーク群
　ＭＬ１、ＭＲ１、ＭＣ１　情報用記録マーク
　ＭＧ２　判別用マーク群
　ＭＬ２、ＭＲ２　判別用記録マーク
　ＬＢ１　ガイドレーザ光
　ＬＢ２　記録再生レーザ光 DESCRIPTION OF SYMBOLS 11 Optical disk 12 Guide layer 13 Recording layer 100 Recording / reproducing apparatus 102 Optical pick-up 103 Signal recording / reproducing part 111 CPU
120 Tracking control circuit 130 Mark group detection circuit 1315 Comparator 1316 Synchronization data detector 1320 Pre-data detector TR Guide track GT Groove track LT Land track CT Center track MG1 Information mark group ML1, MR1, MC1 Information recording mark MG2 Discrimination Mark group ML2, MR2 Discriminating recording mark LB1 Guide laser beam LB2 Recording / reproducing laser beam

Claims (18)

  1. 　(i-1)トラッキング用のガイドトラックが形成されているガイド層と、(i-2)前記ガイド層上に積層されている複数の記録層とを備える記録媒体であって、(ii)前記ガイド層には、(ii-1)互いに隣接する複数のガイドトラックの夫々に形成される情報用マーク群と、(ii-2)前記情報用マーク群が形成されている前記複数のガイドトラックのうち中心付近に位置するガイドトラックであるセンタートラックを判別するための判別用マーク群とが形成されており、(iii)前記判別用マーク群は、(iii-1)前記センタートラックのトラック中心を基準として左右に所定距離シフトしている一対の判別用記録マークであって、且つ(iii-2)夫々の判別用記録マークの幅が前記ガイドトラックの幅の２倍以上となる一対の判別用記録マークを含んでいる記録媒体に対して記録動作及び再生動作の少なくとも一方を行う記録再生装置であって、
    　前記判別用マーク群に照射された前記ガイドレーザ光の戻り光から第１プッシュプル信号を検出する検出手段と、
    　前記検出手段が検出した前記第１プッシュプル信号に基づいて、前記ガイドレーザ光がトレースしている前記ガイドトラックが前記センタートラックであるか否かを判別する判別手段と
    　を備えることを特徴とする記録再生装置。     (i-1) a recording medium comprising a guide layer in which a guide track for tracking is formed, and (i-2) a plurality of recording layers stacked on the guide layer, (ii) The guide layer includes (ii-1) an information mark group formed on each of a plurality of guide tracks adjacent to each other, and (ii-2) a plurality of guide tracks on which the information mark group is formed. A discriminating mark group for discriminating a center track which is a guide track located in the vicinity of the center, and (iii) the discriminating mark group is (iii-1) the track center of the center track. A pair of discriminating recording marks shifted by a predetermined distance to the left and right as a reference, and (iii-2) a pair of discriminating records in which the width of each discriminating recording mark is at least twice the width of the guide track Recording to a recording medium containing a recording mark A recording and reproducing apparatus for performing at least one of the work and reproducing operation,
    Detecting means for detecting a first push-pull signal from the return light of the guide laser light irradiated on the discrimination mark group;
    And determining means for determining whether or not the guide track traced by the guide laser beam is the center track based on the first push-pull signal detected by the detecting means. Recording / playback device.
  2. 　前記判別手段は、前記判別用マーク群を構成する前記一対の判別用記録マークの組み合わせに応じて変化する前記第１プッシュプル信号の信号レベルに基づいて、前記ガイドレーザ光がトレースしている前記ガイドトラックが前記センタートラックであるか否かを判別することを特徴とする請求項１に記載の記録再生装置。 The discriminating means traces the guide laser beam based on the signal level of the first push-pull signal that changes in accordance with the combination of the pair of discriminating recording marks constituting the discriminating mark group. 2. The recording / reproducing apparatus according to claim 1, wherein it is determined whether or not a guide track is the center track.
  3. 　前記判別手段は、前記判別用マーク群を構成する前記一対の判別用記録マークの組み合わせに応じて変化する前記第１プッシュプル信号の信号レベルを、所定の処理単位毎に所定の閾値と比較することで、前記ガイドレーザ光がトレースしている前記ガイドトラックが前記センタートラックであるか否かを判別することを特徴とする請求項１に記載の記録再生装置。 The discriminating means compares the signal level of the first push-pull signal, which changes according to the combination of the pair of discriminating recording marks constituting the discriminating mark group, with a predetermined threshold for each predetermined processing unit. The recording / reproducing apparatus according to claim 1, wherein it is determined whether or not the guide track traced by the guide laser beam is the center track.
  4. 　前記検出手段は、前記情報用マーク群に照射された前記ガイドレーザ光の戻り光から第２プッシュプル信号を更に検出し、
    　前記第２プッシュプル信号に基づいて、前記判別手段によって前記センタートラックであると判別された前記ガイドトラックが中心付近に位置する前記複数のガイドトラックの夫々に形成されている前記情報用マーク群に応じたビットデータを取得する取得手段と、
    　前記取得手段が取得したビットデータに基づいて、前記複数の記録層に対する前記記録動作及び前記再生動作の少なくとも一方を行う記録再生手段と
    　を更に備えることを特徴とする請求項１に記載の記録再生装置。     The detection means further detects a second push-pull signal from the return light of the guide laser light irradiated on the information mark group,
    Based on the second push-pull signal, the information track group formed on each of the plurality of guide tracks in which the guide track determined to be the center track by the determining means is located near the center. Obtaining means for obtaining the corresponding bit data;
    The recording / reproducing device according to claim 1, further comprising: a recording / reproducing unit that performs at least one of the recording operation and the reproducing operation with respect to the plurality of recording layers based on the bit data obtained by the obtaining unit. apparatus.
  5. 　前記取得手段は、前記判別手段によって前記センタートラックであると判別されなかった前記ガイドトラック上に形成されている前記情報用マーク群に応じたビットデータを取得しないことを特徴とする請求項４に記載の記録再生装置。 5. The acquisition unit according to claim 4, wherein the acquisition unit does not acquire bit data corresponding to the information mark group formed on the guide track that is not determined to be the center track by the determination unit. The recording / reproducing apparatus as described.
  6. 　前記記録再生手段は、(i)前記取得手段が取得した前記ビットデータを所定数だけ蓄積すると共に、(ii)前記所定数だけ蓄積した前記ビットデータに対してまとめて誤り訂正処理することで得られる前記ビットデータに基づいて、前記複数の記録層に対する前記記録動作及び前記再生動作の少なくとも一方を行うことを特徴とする請求項４に記載の記録再生装置。 The recording / reproducing means is obtained by (i) accumulating a predetermined number of the bit data obtained by the obtaining means, and (ii) performing error correction processing on the bit data accumulated by the predetermined number collectively. 5. The recording / reproducing apparatus according to claim 4, wherein at least one of the recording operation and the reproducing operation with respect to the plurality of recording layers is performed based on the bit data to be recorded.
  7. 　前記所定数は、ＥＣＣブロックを構成するワードのビット数であることを特徴とする請求項６に記載の記録再生装置。 The recording / reproducing apparatus according to claim 6, wherein the predetermined number is the number of bits of a word constituting an ECC block.
  8. 　前記判別用マーク群は、(i)同一の回転位相位置に形成される前記一対の判別用記録マーク及び(ii)異なる回転位相位置に形成される前記一対の判別用記録マークの少なくとも一方を含んでいることを特徴とする請求項１に記載の記録再生装置。 The determination mark group includes (i) at least one of the pair of determination recording marks formed at the same rotational phase position and (ii) the pair of determination recording marks formed at different rotational phase positions. The recording / reproducing apparatus according to claim 1, wherein
  9. 　同一の回転位相位置に形成される前記一対の判別用記録マークは、(i)前記センタートラックにスポット中心が一致するガイドレーザ光を前記一対の判別用記録マークに照射することで得られるプッシュプル信号の信号レベルの絶対値が第１閾値以下となり、且つ(ii)前記情報用マーク群が形成されている前記複数のガイドトラックのうち前記センタートラック以外の他のガイドトラックにスポット中心が一致する前記ガイドレーザ光を前記一対の判別用記録マークに照射することで得られるプッシュプル信号の信号レベルの絶対値が前記第１閾値より大きくなるように形成されることを特徴とする請求項８に記載の記録再生装置。 The pair of discriminating recording marks formed at the same rotational phase position is (i) a push-pull obtained by irradiating the pair of discriminating recording marks with a guide laser beam whose spot center coincides with the center track. The absolute value of the signal level of the signal is equal to or less than the first threshold, and (ii) the spot center coincides with a guide track other than the center track among the plurality of guide tracks on which the information mark group is formed. 9. The push-pull signal obtained by irradiating the pair of determination recording marks with the guide laser beam has an absolute value greater than the first threshold value. The recording / reproducing apparatus as described.
  10. 　異なる回転位相位置に形成される前記一対の判別用記録マークは、前記センタートラックにスポット中心が一致するガイドレーザ光を前記一対の判別用記録マークに照射することで得られるプッシュプル信号の信号レベルの絶対値が第１閾値より大きくなるように形成されることを特徴とする請求項８に記載の記録再生装置。 The pair of discriminating recording marks formed at different rotational phase positions has a signal level of a push-pull signal obtained by irradiating the pair of discriminating recording marks with guide laser light whose spot center coincides with the center track. 9. The recording / reproducing apparatus according to claim 8, wherein the absolute value of the recording / reproducing apparatus is larger than the first threshold value.
  11. 　前記判別用マーク群は、当該判別用マーク群が形成されている複数のガイドトラックの夫々において、(i)当該夫々のガイドトラックにスポット中心が一致するガイドレーザ光を照射することで得られるプッシュプル信号の信号レベルの絶対値が第１閾値より大きくなる第１領域が２つ以上含まれるように、(ii)当該夫々のガイドトラックにスポット中心が一致する前記ガイドレーザ光を照射することで得られる前記プッシュプル信号の信号レベルの絶対値が前記第１閾値よりも小さい第２閾値以下となる第２領域が２つ以上含まれるように、又は(iii)前記第１領域及び前記第２領域が共に１つずつ以上含まれるように形成されていることを特徴とする請求項１に記載の記録再生装置。 The discriminating mark group is a push obtained by irradiating a guide laser beam whose spot center coincides with each guide track in each of the plurality of guide tracks on which the discriminating mark group is formed. (Ii) By irradiating each guide track with the guide laser beam whose spot center coincides so that two or more first regions where the absolute value of the signal level of the pull signal is greater than the first threshold value are included. Two or more second regions in which the absolute value of the signal level of the obtained push-pull signal is less than or equal to the second threshold smaller than the first threshold are included, or (iii) the first region and the second 2. The recording / reproducing apparatus according to claim 1, wherein each of the areas is formed so as to include one or more areas.
  12. 　前記一対の判別用記録マークの夫々の幅は、前記ガイド層に照射されるガイドレーザ光が前記ガイド層上で形成するビームスポットの幅の１／２倍以上になることを特徴とする請求項１に記載の記録再生装置。 The width of each of the pair of recording marks for discrimination is ½ times or more the width of a beam spot formed on the guide layer by the guide laser light irradiated on the guide layer. 2. The recording / reproducing apparatus according to 1.
  13. 　前記ガイドトラックは、交互に形成されたグルーブトラック及びランドトラックを含み、
    　前記判別用マーク群は、(i)前記情報用マーク群が形成されている前記複数のグルーブトラックのうち中心付近に位置するグルーブセンタートラックを識別するための判別用マーク群として、(i-1)前記グルーブセンタートラックのトラック中心を基準として左右に所定距離シフトしている一対の判別用記録マークであって、且つ(ii-2)夫々の判別用記録マークの幅が前記グルーブトラックの幅の２倍以上となる一対の判別用記録マークを含んでおり、
    　前記判別用マーク群は、(ii)前記情報用マーク群が形成されている前記複数のランドトラックのうち中心付近に位置するランドセンタートラックを識別するための判別用マーク群として、(ii-1)前記ランドセンタートラックのトラック中心を基準として左右に所定距離シフトしている一対の判別用記録マークであって、且つ(ii-2)夫々の判別用記録マークの幅が前記ランドトラックの幅の２倍以上となる一対の判別用記録マークを含んでいることを特徴とする請求項１に記載の記録再生装置。     The guide track includes a groove track and a land track formed alternately,
    The discrimination mark group is (i) as a discrimination mark group for identifying a groove center track located near the center among the plurality of groove tracks on which the information mark group is formed. ) A pair of discriminating recording marks shifted by a predetermined distance from side to side with respect to the track center of the groove center track, and (ii-2) the width of each discriminating recording mark is equal to the width of the groove track. Includes a pair of discriminating recording marks that are more than doubled,
    The determination mark group includes (ii) a determination mark group for identifying a land center track located near the center among the plurality of land tracks on which the information mark group is formed. ) A pair of discriminating recording marks shifted by a predetermined distance from side to side with respect to the track center of the land center track, and (ii-2) the width of each discriminating recording mark is equal to the width of the land track. 2. The recording / reproducing apparatus according to claim 1, further comprising a pair of discriminating recording marks which is twice or more.
  14. 　前記ガイド層に照射されるガイドレーザ光が前記ガイド層上で形成するビームスポットに包含される複数のガイドトラックのうちの少なくとも二つのガイドトラックの夫々の同一の回転位相位置に、当該夫々のガイドトラックのトラック中心を基準として左右に所定距離シフトしている一対の情報用記録マークが組み合わせられた同一の前記情報用マーク群が形成されるように、前記情報用マーク群が前記ガイド層に形成されていることを特徴とする請求項１に記載の記録再生装置。 Each of the guides at the same rotational phase position of at least two of the plurality of guide tracks included in a beam spot formed on the guide layer by the guide laser light irradiated on the guide layer. The information mark group is formed on the guide layer so that the same information mark group is formed by combining a pair of information recording marks shifted by a predetermined distance from side to side with respect to the track center of the track. The recording / reproducing apparatus according to claim 1, wherein:
  15. 　前記複数のガイドトラックの夫々の同一の回転位相位置に、同一の前記情報用マーク群が形成されていることを特徴とする請求項１４に記載の記録再生装置。 15. The recording / reproducing apparatus according to claim 14, wherein the same information mark group is formed at the same rotational phase position of each of the plurality of guide tracks.
  16. 　前記ガイドトラックは、交互に形成されたグルーブトラック及びランドトラックを含み、
    　前記ビームスポットに包含される複数のグルーブトラックの夫々の同一位相位置に、当該夫々のグルーブトラックのトラック中心を基準として左右に所定距離シフトしている一対の情報用記録マークが組み合わせられた情報用マーク群が形成されており、
    　前記ビームスポットに包含される複数のランドトラックの夫々の同一位相位置に、当該夫々のランドトラックのトラック中心を基準として左右に所定距離シフトしている一対の情報用記録マークが組み合わせられた情報用マーク群が形成されていることを特徴とする請求項１４に記載の記録再生装置。     The guide track includes a groove track and a land track formed alternately,
    A pair of information recording marks that are shifted to the left and right by a predetermined distance with respect to the track center of each groove track at the same phase position of each of the plurality of groove tracks included in the beam spot. Marks are formed,
    A pair of information recording marks that are shifted to the left and right by a predetermined distance with respect to the track center of each land track at the same phase position of each of the plurality of land tracks included in the beam spot. 15. The recording / reproducing apparatus according to claim 14, wherein a mark group is formed.
  17. 　前記検出手段は、前記情報用マーク群に照射された前記ガイドレーザ光の戻り光から第２プッシュプル信号を更に検出し、
    　前記第２プッシュプル信号に基づいて、前記判別手段によって前記センタートラックであると判別された前記ガイドトラックが中心付近に位置する前記複数のガイドトラックの夫々に形成されている前記情報用マーク群に応じたビットデータを取得する取得手段と、
    　前記取得手段が取得したビットデータに基づいて、前記複数の記録層に対する前記記録動作及び前記再生動作の少なくとも一方を行う記録再生手段と
    　を更に備え、
    　前記取得手段は、前記情報用マーク群を構成する前記一対の情報用記録マークの組み合わせに応じて変化する前記第２プッシュプル信号の信号レベルに基づいて、前記ビットデータを取得することを特徴とする請求項１４に記載の記録再生装置。     The detection means further detects a second push-pull signal from the return light of the guide laser light irradiated on the information mark group,
    Based on the second push-pull signal, the information track group formed on each of the plurality of guide tracks in which the guide track determined to be the center track by the determining means is located near the center. Obtaining means for obtaining the corresponding bit data;
    Recording / reproducing means for performing at least one of the recording operation and the reproducing operation on the plurality of recording layers based on the bit data obtained by the obtaining means,
    The acquisition means acquires the bit data based on a signal level of the second push-pull signal that changes in accordance with a combination of the pair of information recording marks constituting the information mark group. The recording / reproducing apparatus according to claim 14.
  18. 　(i-1)トラッキング用のガイドトラックが形成されているガイド層と、(i-2)前記ガイド層上に積層されている複数の記録層とを備える記録媒体であって、(ii)前記ガイド層には、(ii-1)互いに隣接する複数のガイドトラックの夫々に形成される情報用マーク群と、(ii-2)前記情報用マーク群が形成されている前記複数のガイドトラックのうち中心付近に位置するガイドトラックであるセンタートラックを判別するための判別用マーク群とが形成されており、(iii)前記判別用マーク群は、(iii-1)前記センタートラックのトラック中心を基準として左右に所定距離シフトしている一対の判別用記録マークであって、且つ(iii-2)夫々の判別用記録マークの幅が前記ガイドトラックの幅の２倍以上となる一対の判別用記録マークを含んでいる記録媒体に対して記録動作及び再生動作の少なくとも一方を行う記録再生方法であって、
    　前記判別用マーク群に照射された前記ガイドレーザ光の戻り光から第１プッシュプル信号を検出する検出工程と、
    　前記検出工程が検出した前記第１プッシュプル信号に基づいて、前記ガイドレーザ光がトレースしている前記ガイドトラックが前記センタートラックであるか否かを判別する判別工程と
    　を備えることを特徴とする記録再生方法。     (i-1) a recording medium comprising a guide layer in which a guide track for tracking is formed, and (i-2) a plurality of recording layers stacked on the guide layer, (ii) The guide layer includes (ii-1) an information mark group formed on each of a plurality of guide tracks adjacent to each other, and (ii-2) a plurality of guide tracks on which the information mark group is formed. A discriminating mark group for discriminating a center track which is a guide track located in the vicinity of the center, and (iii) the discriminating mark group is (iii-1) the track center of the center track. A pair of discriminating recording marks shifted by a predetermined distance to the left and right as a reference, and (iii-2) a pair of discriminating records in which the width of each discriminating recording mark is at least twice the width of the guide track Recording to a recording medium containing a recording mark A recording and reproducing method of performing at least one of work and reproducing operation,
    A detection step of detecting a first push-pull signal from the return light of the guide laser light irradiated on the discrimination mark group;
    And a determination step of determining whether or not the guide track traced by the guide laser beam is the center track based on the first push-pull signal detected by the detection step. Recording and playback method.
PCT/JP2012/063800 2012-05-29 2012-05-29 Record/play device and method WO2013179396A1 (en)

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