JPWO2013108400A1 - Recording / reproducing apparatus and method - Google Patents

Abstract

A recording / reproducing operation is performed on a recording medium in which information is suitably recorded on the guide layer while suppressing the influence on the tracking control. The recording / reproducing apparatus (100) is a recording medium including a guide layer (12) on which guide tracks (TR, GT, LT) are formed and a recording layer (13), and a beam of guide laser light (LB1). The same mark group (MG) in which a pair of recording marks (ML, MR) shifted by a predetermined distance from the track center to the left and right are combined at the same rotational phase position of each of the plurality of guide tracks included in the spot. ) And a reading means (103) for performing a recording / reproducing operation on the recording medium (11) on which the recording medium is formed and reading the bit data based on the push-pull signal obtained from the return light of the guide laser beam, and the bit data Recording / reproducing means (111) for performing a recording / reproducing operation on the recording layer based on the control information to be recorded.

Description

  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.

  As a recording medium having 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 in which a guide track for tracking 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.

  Although not a prior art document disclosing a guide layer separation type optical disc, Patent Documents 2 to 8 are cited as prior art documents related to the present invention described later.

Japanese Patent No. 4037034 Japanese Patent No. 3729467 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

  By the way, in such a recording medium, there is a demand for recording in advance on the guide layer some data (for example, data indicating control information such as address information, clock information, and recording start timing information). In this case, a method of recording data on the guide layer by forming the combination of the recording mark and the recording space on the guide layer as well as the combination of the recording mark and the recording space recorded on the recording layer is assumed as an example. Is done.

  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.

  The present invention provides a recording medium capable of suitably recording data while suppressing the influence on the tracking control with respect to the guide layer on which the tracking guide track is formed in the above-described optical disc having a large number of recording layers. 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.

  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) each of at least two guide tracks among a plurality of guide tracks included in a beam spot formed on the guide layer by a guide laser beam irradiated on the guide layer. Recording operation on a recording medium in which the same mark group is formed by combining a pair of recording marks shifted by a predetermined distance left and right with respect to the track center of each guide track at the same rotational phase position And a recording / reproducing apparatus that performs at least one of the reproducing operations, based on a push-pull signal obtained from a return light of the guide laser light from the guide layer, And at least one of the recording operation and the reproducing operation with respect to the plurality of recording layers, based on control means configured by reading means for reading bit data corresponding to a key group and bit data read by the reading means. Recording and reproducing means.

  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) each of at least two guide tracks among a plurality of guide tracks included in a beam spot formed on the guide layer by a guide laser beam irradiated on the guide layer. Recording operation on a recording medium in which the same mark group is formed by combining a pair of recording marks shifted by a predetermined distance left and right with respect to the track center of each guide track at the same rotational phase position And a recording / reproducing method for performing at least one of the reproducing operations, based on a push-pull signal obtained from a return light of the guide laser light from the guide layer, A reading process for reading bit data corresponding to a key group, and a recording / reproducing process for performing at least one of the recording operation and the reproducing operation for the plurality of recording layers based on the bit data read by the reading process. .

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). 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 recording mark which comprises the mark group formed in a groove track. 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 formed in a groove track. It is a top view which shows the structure of a pair of recording mark which comprises the mark group formed in a land track. 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 formed in a land track. It is a data structure figure which shows the data structure of a guide layer (further, a recording layer). It is a top view which shows an example of the mark group formed in a specific slot. It is a top view which shows the aspect by which a some mark group is disperse | distributed and recorded on a some slot. 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. It is a top view which shows the comparative example in which a mark group is formed on a single groove track. It is a graph which shows the relationship between a focus deviation and the amplitude of a push pull signal. 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, and a pair of recording mark. It is a graph which shows the push pull signal obtained from the mark group which comprises a pair of recording marks and the synchronous data containing the recording mark located on a track center. It is a top view which shows the 1st modification of the aspect in which many types of data are recorded by the mark group formed in a groove track. It is a top view which shows the 1st modification of the aspect in which many types of data are recorded by the mark group formed in a land track. It is a top view which shows the 2nd modification of the aspect in which many types of data are recorded by the mark group formed in a land track. It is a top view which shows the 3rd modification of the aspect by which many types of data are recorded by the mark group formed in a land track. It is a top view which shows the 4th modification of the aspect by which many types of data are recorded by the mark group formed in a groove track. It is a top view which shows the 4th modification of the aspect by which many types of data are recorded by the mark group formed in a land track. It is a top view which shows the 5th modification of the aspect by which many types of data are recorded by the mark group formed in a groove track. It is a top view which shows the 5th modification of the aspect by which many types of data are recorded by the mark group formed in a land track. It is a top view which shows the 6th modification of the aspect in which many types of data are recorded by the mark group formed in a groove track. It is a top view which shows the 7th modification of the aspect by which many types of data are recorded by the mark group formed in a groove track. It is a top view which shows the 8th modification of the aspect in which many types of data are recorded by the mark group formed in a groove track. It is a top view which shows the 9th modification of the aspect by which many types of data are recorded by the mark group formed in a land track. It is a block diagram which shows the structure of the recording / reproducing apparatus of a present Example. It is a block diagram which shows the structure of a signal recording / reproducing part. It is a flowchart which shows the flow of the whole operation | movement of the recording / reproducing apparatus of a present Example. It is a flowchart which shows the flow of recording operation | movement (step S50 of FIG. 29) of the recording / reproducing apparatus of a present Example. It is a flowchart which shows the flow of the reproducing operation (step S70 of FIG. 29) of the recording / reproducing apparatus of a present Example.

  Hereinafter, embodiments of the recording / reproducing apparatus and method will be described in order.

(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 same rotational phase of each of at least two guide tracks of a plurality of guide tracks included in a beam spot formed on the guide layer by a guide laser beam irradiated on the guide layer. The recording operation and the reproduction operation are performed on the recording medium in which the same mark group is formed at a position where a pair of recording marks shifted by a predetermined distance from side to side with respect to the track center of each guide track is combined. A recording / reproducing apparatus that performs at least one of the recording and reproducing devices according to the mark group based on a push-pull signal obtained from the return light of the guide laser light from the guide layer. Reading means for reading bit data; and recording / reproducing means for performing at least one of the recording operation and the reproducing operation for the plurality of recording layers based on control information composed of the bit data read by the reading means. .

  According to 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, the recording medium 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.

  In the present embodiment, a mark group is formed on the guide layer. Specifically, the mark group is formed at the same rotational phase position of at least two guide tracks among a plurality of guide tracks included in a beam spot formed by the guide laser beam on the guide layer. That is, the same mark group indicating the same bit data (for example, bit data of 1 bit to several bits or tens of bits) is at least two of a plurality of guide tracks included in the beam spot of the guide laser beam. Each guide track is formed so as to be adjacent to each other along a direction orthogonal to the traveling direction of the guide track. At this time, the mark group is formed on at least two guide tracks among a plurality of guide tracks included in a beam spot formed by the guide laser beam on the guide layer. That is, the number of guide tracks on which the same 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 greater than two.

  Further, the mark group formed at the same rotational phase position of at least two guide tracks is a mark group in which a pair of recording marks shifted by a predetermined distance from the track center of the guide track to the left and right are combined. . That is, the mark group includes a pair of 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 in any manner. It becomes a combined mark group. As such a pair of 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 along the traveling direction of the guide track. A pair of recording marks arranged in this order, a recording mark shifted to the right by a predetermined distance from the track center, and a recording mark shifted by a predetermined distance to the left from the track center are the traveling directions of the guide track An example is a pair of recording marks arranged in this order along. Therefore, the mark group may be a mark group in which only one pair of such recording marks is combined (that is, a mark group that matches the pair of recording marks themselves), or such a pair of recording marks. May be a mark group combined in an arbitrary manner. Alternatively, as described later, the mark group may be a mark group in which such a pair of recording marks and other recording marks (for example, a recording mark located on the track center) are combined in an arbitrary manner. Good.

  A more specific configuration will be exemplified and described. 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. A 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 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. A mark group that is a pair of recording marks, 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, It 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 °. A mark group is formed, which is a pair of recording marks, in which the recording marks and the recording marks shifted by a predetermined distance to the left with respect to the track center are arranged in this order along the traveling direction of the guide track. Also good.

  Note that all the mark groups formed on the guide layer may not be a mark group in which the pair of recording marks described above are combined. For example, while a part of the mark group formed on the guide layer is a mark group that becomes the above-described pair of recording marks themselves (or a combination of the above-described pair of recording marks), the mark group formed on the guide layer The other part may be an arbitrary recording mark that does not include the pair of recording marks described above (for example, a recording mark positioned on the center of the track).

  The recording / reproducing apparatus of the present embodiment performs at least one of a recording operation and a reproducing operation on the recording medium of the present embodiment on which such mark groups are formed. Specifically, the reading unit is configured to generate bit data corresponding to the mark group based on a push-pull signal obtained from the return light of the guide laser beam (for example, as described above, a pair of recording marks constituting the mark group). Read bit data according to the combination). The recording / reproducing means performs at least one of a recording operation and a reproducing operation for the plurality of recording layers based on the bit data. For this reason, the recording / reproducing apparatus of this embodiment has the following advantages.

  First, according to the present embodiment, the mark group formed in the guide layer is a mark group in which a pair of recording marks shifted by a predetermined distance from side to side with respect to the track center of the guide track is combined. For this reason, even if such a mark group is formed on the guide layer, the average value of the signal level fluctuation that the mark group can exert on the push-pull signal is zero (however, a margin that can be regarded as substantially zero). Included). Therefore, the presence of the 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.

  On the other hand, by assigning different bit data to the mark group according to the combination of the pair of recording marks constituting the mark group, the bit data can be recorded on the guide layer using the mark group. Such bit data (that is, the difference in the combination of a pair of recording marks) can be easily read by monitoring the change in the instantaneous value of the signal level variation 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 mark group formed in advance on the guide layer based on the push-pull signal. Can do.

  In addition, according to the present embodiment, the same mark group is formed at the same rotational phase position of each of at least two guide tracks among the plurality of guide tracks included in the beam spot of the guide laser light. Therefore, as will be described in detail later with reference to the drawings, the recording / reproducing apparatus can read the bit data corresponding to the mark group without being affected by the focus offset deviation (so-called defocus) of the guide laser beam. it can.

  As described above, according to the recording / reproducing apparatus 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.

<2>
In another aspect of the recording / reproducing apparatus of the present embodiment, the reading unit reads the bit data corresponding to a combination of the pair of recording marks constituting the mark group.

  According to this aspect, the reading means is based on the push-pull signal, and the bit data corresponding to the combination of the pair of recording marks constituting the mark group (for example, the difference in the combination of the pair of recording marks constituting the mark group). The corresponding bit data) can be suitably read.

<3>
In another aspect of the recording / reproducing apparatus of the present embodiment, the reading unit reads the bit data based on a level fluctuation of the push-pull signal according to a combination of the pair of recording marks constituting the mark group. .

  According to this aspect, the reading means is based on the push-pull signal, and the bit data corresponding to the combination of the pair of recording marks constituting the mark group (for example, the difference in the combination of the pair of recording marks constituting the mark group). The corresponding bit data) can be suitably read.

<4>
In another aspect of the recording / reproducing apparatus of the present embodiment, the depth of the pair of recording marks is λ / 6n (where λ is the wavelength of the guide laser beam and n is the refractive index of the substrate of the recording medium). Is less than.

  According to this aspect, since the tracking control and the reading of the mark group (that is, reading of the bit data indicated by the mark group) are performed using the push-pull signal as described above, the depth of the recording mark is pushed. It can be set according to the characteristics of the signal level of the pull signal. That is, the depth of the recording mark can be set according to the signal level characteristic of the push-pull signal without considering the signal level characteristic of the RF signal.

<5>
In another aspect of the recording / reproducing apparatus of this embodiment, the pair of recording marks has a depth of λ / 8n (where λ is the wavelength of the guide laser beam and n is the refractive index of the substrate of the recording medium). It is.

  According to this aspect, since the tracking control and the reading of the mark group (that is, reading of the bit data indicated by the mark group) are performed using the push-pull signal as described above, the depth of the recording mark is pushed. The depth at which the signal level characteristic of the pull signal is optimal can be set. That is, the depth of the recording mark can be set to a depth at which the signal level characteristic of the push-pull signal is the best without considering the signal level characteristic of the RF signal.

<6>
In another aspect of the recording / reproducing apparatus of the present embodiment, the same mark group is formed at the same rotational phase position of each of the plurality of guide tracks.

  According to this aspect, the same 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 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 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 reads bit data corresponding to the mark group without being further affected by the deviation (so-called defocus) of the focus offset of the guide laser beam. be able to.

<7>
In another aspect of the recording / reproducing apparatus of the present embodiment, the same mark group is located at the same rotational phase position of each of the other guide tracks excluding at least one guide track located near the center of the plurality of guide tracks. Is formed.

  According to this aspect, the mark group is not formed on at least one (preferably, one) guide track located near the center of the plurality of guide tracks included in the beam spot of the guide laser beam. Get better. For this reason, the formation of mark groups (in other words, the production of a recording medium on which such mark groups are formed) is relatively simplified.

<8>
In another aspect of the recording / reproducing apparatus of the present embodiment, the pair of recording marks is located at the same rotational phase position of each of the other guide tracks excluding at least one guide track located on the outermost side among the plurality of guide tracks. Are formed at the same rotational phase position of the at least one guide track located on the outermost side, and instead of the pair of recording marks, the track of the at least one guide track is formed. A mark group is formed by combining the single recording marks shifted by the predetermined distance in the center direction of the beam spot with respect to the center.

  According to this aspect, there is a possibility that part of the pair of recording marks constituting the mark group formed on the outermost guide track is not included in the beam spot of the guide laser beam. For this reason, according to this aspect, one of the pair of recording marks that may not be included in the beam spot of the guide laser beam does not need to be shifted with reference to the track center. For this reason, the formation of mark groups (in other words, the production of a recording medium on which such mark groups are formed) is relatively simplified.

<9>
In another aspect of the recording / reproducing apparatus of the present embodiment, the mark group includes (i) a mark group in which the pair of recording marks are combined, and (ii) a track of the pair of recording marks and the respective guide tracks. A mark group in which other recording marks located on the center are combined, and the reading unit corresponds to the pair of recording marks on the basis of the signal level of the push-pull signal corresponding to the other recording marks. The bit data is read by identifying the signal level of the push-pull signal.

  According to this aspect, in addition to the mark group in which the pair of recording marks are combined, the mark group in which the pair of recording marks and other recording marks located on the track center are combined is formed on the guide layer. . For this reason, the recording / reproducing apparatus reads a mark group in which a pair of recording marks and another recording mark located on the center of the track are combined to change the signal level of the push-pull signal according to the pair of recording marks. In addition, it is also possible to recognize a change in the signal level of the push-pull signal corresponding to another recording mark located on the track center (that is, a so-called zero level fluctuation that serves as a reference value for the signal level). Therefore, the recording / reproducing apparatus can detect other recording marks located on the track center even when the reference value of the signal level of the push-pull signal fluctuates (for example, an offset of the DC component occurs). The fluctuation of the signal level of the push-pull signal corresponding to the pair of recording marks can be suitably recognized on the basis of the signal level of the corresponding push-pull signal. Therefore, the recording / reproducing apparatus can suitably read the bit data recorded on the guide layer using the mark group.

<10>
In the aspect of the recording / reproducing apparatus in which the mark group in which the pair of recording marks and the other recording marks located on the track center are combined as described above is formed, the mark group in which the pair of recording marks is combined A mark group indicating predetermined bit data to be recorded on the guide layer, and a mark group in which the pair of recording marks and another recording mark located on the track center are combined is used when the bit data is read. You may comprise so that it may be a mark group which shows the synchronous data used in order to take a synchronization.

  According to this configuration, the recording / reproducing apparatus reads the synchronization data before reading the bit data, and therefore can recognize the fluctuation of the reference value of the signal level of the push-pull signal based on the reading result of the synchronization data. it can. Therefore, even when the reference value of the signal level of the push-pull signal fluctuates, the recording / reproducing apparatus can suitably read the bit data recorded on the guide layer using the mark group.

<11>
In another aspect of the recording / reproducing apparatus of this embodiment, the mark group includes the pair of pairs so that an average value of a signal level of a push-pull signal obtained by irradiating the mark group with the guide laser light becomes zero. These recording marks are combined.

  According to this aspect, even if such a mark group is formed on the guide layer, the average value of the signal level fluctuation that can be exerted on the push-pull signal by the mark group is zero (however, it is substantially regarded as zero. Including the margin to obtain). Therefore, the presence of the mark group has little or no adverse effect on the tracking control based on the push-pull signal.

<12>
In another aspect of the recording / reproducing apparatus of the present embodiment, the mark group includes the number of recording marks shifted to the left with respect to the track center and the number of recording marks shifted to the right with respect to the track center. It is formed so that the number is equal.

  According to this aspect, even if such a mark group is formed on the guide layer, the average value of the signal level fluctuation that can be exerted on the push-pull signal by the mark group is zero (however, it is substantially regarded as zero. Including the margin to obtain). Therefore, the presence of the mark group has little or no adverse effect on the tracking control based on the push-pull signal.

<13>
In another aspect of the recording / reproducing apparatus of the present embodiment, a plurality of different mark groups are discretely formed on the guide layer, and the recording / reproducing means includes a plurality of mark groups corresponding to the plurality of different mark groups. Based on the control information obtained by combining the bit data, at least one of the recording operation and the reproducing operation with respect to the plurality of recording layers is performed.

  According to this aspect, by combining a plurality of different bit data according to a plurality of different mark groups formed discretely, control information (for example, address information) that is relatively larger than the bit data. Clock information, recording start timing information, etc.) can be recorded on the guide layer. For this reason, the recording / reproducing apparatus reads control information whose size is relatively larger than bit data by combining a plurality of different bit data corresponding to a plurality of different mark groups formed discretely. Can do. Therefore, the recording / reproducing apparatus can perform at least one of the recording operation and the reproducing operation on a plurality of recording layers based on such control information.

<14>
In another aspect of the recording / reproducing apparatus of the present embodiment, one mark group formed at the same phase position of each of a plurality of guide tracks including one guide track as a center is different from the one guide track. Are formed at a rotational phase position different from other mark groups formed at the same rotational phase position of each of the plurality of guide tracks including the guide track.

  According to this aspect, at least a part of one mark group and at least a part of another mark group different from the one mark group are formed redundantly at the same rotational phase position of the same guide track. Nothing will happen. Therefore, even when the same mark group is formed on each of the plurality of guide tracks, one mark group is preferably formed without being influenced by other mark groups (in other words, interference). The For this reason, even when the same mark group is formed on each of the plurality of guide tracks, the recording / reproducing apparatus does not receive the influence (in other words, interference) of the other mark group. Can be suitably read.

<15>
In another aspect of the recording / reproducing apparatus of this embodiment, the guide track includes a groove track and a land track that are alternately formed, and each of the plurality of groove tracks included in the beam spot has the same phase position. A mark group is formed by combining a pair of recording marks shifted by a predetermined distance from side to side with respect to the track center of each groove track, and each of the plurality of land tracks included in the beam spot is the same. At the phase position, a mark group is formed by combining a pair of recording marks shifted by a predetermined distance from side to side with respect to the track center of each land track.

  According to this aspect, mark groups are formed on both the groove track and the land track. Therefore, the recording / reproducing apparatus can read the bit data corresponding to the mark group by irradiating either the groove track or the land track with the guide laser beam.

<16>
In the aspect of the recording / reproducing apparatus in which the mark group is formed on the land track as described above, the mark group formed on the land track is a mark formed simultaneously when forming two groove tracks adjacent to the land track. You may comprise so that it may form as a group.

  If comprised in this way, the mark group formed on a land track will be formed comparatively easily.

(Embodiment of recording / reproducing method)
<17>
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 same rotational phase of each of at least two guide tracks of a plurality of guide tracks included in a beam spot formed on the guide layer by a guide laser beam irradiated on the guide layer. The recording operation and the reproduction operation are performed on the recording medium in which the same mark group is formed at a position where a pair of recording marks shifted by a predetermined distance from side to side with respect to the track center of each guide track is combined. A recording / reproducing method for performing at least one of the method and the method according to the mark group based on a push-pull signal obtained from a return light of the guide laser light from the guide layer. A reading step for reading bit data; and a recording / reproducing step for performing at least one of the recording operation and the reproducing operation for the plurality of recording layers based on control information composed of the bit data read by the reading step. .

  According to the recording / reproducing method of the present embodiment, it is possible to suitably enjoy the same effects as the various effects that the above-described recording / reproducing apparatus of the present embodiment can enjoy.

  Incidentally, the recording / reproducing method of the present embodiment may also take various aspects in response to the various aspects that the recording / reproducing apparatus of the present embodiment can take.

  Such an operation and other advantages of the present embodiment will be further clarified from examples described below.

  As described above, the recording / reproducing apparatus of the present embodiment includes the reading unit and the recording / reproducing unit. The recording / reproducing method of this embodiment includes a reading process and a recording / reproducing process. Accordingly, at least one of a recording operation and a reproducing operation with respect to a recording medium capable of suitably recording data can be performed while suppressing the influence on the tracking control with respect to the guide layer on which the tracking guide track is formed.

  Hereinafter, examples will be described with reference to the drawings.

  Hereinafter, examples will be described with reference to the drawings.

(1) Configuration of Optical Disc First , the configuration of the optical disc 11 will be described with reference to FIG. 1 and FIG. 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.

  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.

  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).

  The optical disk 11 preferably adopts the CLV method. The concentric or spiral guide track TR (specifically, a groove track GT and a land track LT described later) includes control information (for example, clock information, address information, recording start timing) in accordance with the CLV method. Information etc.) is recorded in advance. In the present embodiment, such control information includes a mark group MG (FIG. 4) in which a pair of recording marks ML and MR (see FIGS. 3 and 5) that are shifted equidistant from side to side with respect to the track center. (A) to FIG. 4 (c) and FIGS. 6 (a) to 6 (c)). Such a mark group MG 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 mark group MG in which the pair of recording marks ML and MR are combined will be described in detail later with reference to the drawings after FIG.

  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.

  As shown in FIG. 2, the recording / reproducing laser beam LB <b> 2 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, for example, like 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.

  Each of the plurality of recording layers 13 is a recording layer capable of optically recording and reproducing recorded 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.

  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.

  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.

  In the following description, an example in which the groove track GT and the land track LT have a straight structure is shown for convenience of description. 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) Configuration of Mark Group Formed on Guide Layer Next, referring to FIG. 3 to FIG. 6, the mark group MG formed on the guide layer 12 (that is, shifted equidistant from side to side with reference to the track center). The structure of the mark group MG) in which a pair of recording marks ML and MR are combined will be described.

(2-1) Configuration of Mark Group Formed on Groove Track First , referring to FIG. 3 and FIGS. 4A to 4C, the groove track of the mark group MG formed on the guide layer 12 The configuration of the mark group MG formed on the GT will be described. FIG. 3 is a plan view showing a configuration of a pair of recording marks ML and MR constituting the mark group MG formed on the groove track GT. FIG. 4A to FIG. 4C are plan views showing an aspect in which various types of data (specifically, bit data and synchronization data) are recorded by the mark group MG formed on the groove track GT. is there.

  As shown in FIG. 3, the groove track GT is formed with a pair of recording marks ML and MR 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) a recording mark ML 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) A recording mark MR is formed that is shifted by a predetermined distance to the right side (for example, to the right side with respect to the traveling direction of the groove track GT) with reference to the track center of the groove track GT.

  The mark group MG formed on the groove track GT is composed of such a pair of recording marks ML and MR. For example, FIG. 3 shows a mark group MG formed on the groove track GT as a pair of recording marks ML and MR itself (that is, a single pair of recording marks ML and MR are combined). An example is shown. However, as described later with reference to FIGS. 4A to 4C, the mark group MG formed on the groove track GT is a mark in which a plurality of pairs of recording marks ML and MR are combined. It may be a group MG, or one or more pairs of recording marks ML and MR, and one or more other recording marks (for example, other recording marks MC in which the center of the recording mark is located on the track center (see FIG. 4 (a) to FIG. 4 (c)) or a mark group MG combined with a region where a recording mark is not formed (see FIG. 6 (a) to FIG. 6 (c)).

  In the present embodiment, the same mark group MG is formed at the same rotation phase position (in other words, the same rotation angle position) of each of the plurality of groove tracks GT. That is, the same mark group MG is adjacent or arranged along a direction (that is, the 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). In this way, it is formed on each of the plurality of groove tracks GT. 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”). In the example, a mark group MG in which recording marks ML and recording marks MR are arranged in this order along the traveling direction of the groove track GT is formed at the same rotational phase position.

  In particular, the same mark group MG is formed 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). The In other words, the number of the plurality of groove tracks GT in which the same mark group MG is formed at the same rotational phase position is 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, in FIG. 3, the same mark group MG (that is, the recording mark ML and the recording mark MR are arranged in this order along the traveling direction of the groove track GT at the same rotational phase position of each of the three groove tracks GT. The mark group MG) is formed.

  FIG. 3 shows an example of the mark group MG in which the recording marks ML and the recording marks MR are arranged in this order along the traveling direction of the groove track GT. However, a mark group MG in which recording marks MR and recording marks ML are arranged in this order along the traveling direction of the groove track GT may be used.

  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 is a concave portion, the land track LT is a convex portion, and the recording marks ML and MR are concave portions. However, the groove track GT may be a convex portion, the land track LT may be a concave portion, and the recording marks ML and MR may be convex portions.

  In this embodiment, control 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 a mark group MG. . More specifically, in this embodiment, bit data constituting part of the control information is recorded in advance on the guide layer 12 using the same mark group MG formed at the same rotational phase position. Therefore, one piece of control information can be obtained by combining (in other words, integrating) bit data obtained from a plurality of different mark groups MG formed at a plurality of locations on the guide layer 12. Furthermore, in this embodiment, using such a mark group MG, synchronization data for synchronization when reading bit data constituting at least part of the control information is recorded in the guide layer 12. However, it is not limited to the bit data and the synchronization data constituting at least a part of the control information, and arbitrary data may be recorded in advance on the guide layer 12 using the mark group MG.

  Specifically, as shown in FIG. 4A, the recording mark MC positioned on the track center, the recording mark ML shifted a predetermined distance to the left with respect to the track center, and positioned on the track center. A mark group MG in which a recording mark MC and a recording mark MR 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 groove track GT is a mark constituting the synchronization data The group MG may be formed on the groove track GT. In FIG. 4A, the lengths of the recording mark MC, the recording mark ML, and the recording mark MR (specifically, the length along the traveling direction of the groove track GT) are all “a”. An example is shown.

  In this case, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 for searching the groove track GT in which the mark group MG shown in FIG. 4A is formed is the recording mark MC, the recording mark ML, Due to reading the recording mark MC and the recording mark MR in this order, it changes to “0”, “+ (high)”, “0” and “− (low)” (however, the beam of the guide laser beam LB1) It is assumed that the state in which the center of the spot is shifted to the left from the track center of the groove track GT corresponds to a state in which 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 “−”.

  As shown in FIG. 4B, the recording mark MR shifted by a predetermined distance to the right with respect to the track center and the recording mark ML shifted by a predetermined distance to the left with respect to the track center are the groove tracks GT. The mark groups MG arranged in this order along the traveling direction may be formed on the groove track GT as the mark group MG constituting the bit data (bit 0). FIG. 4B shows an example in which the lengths of the recording marks ML and the recording marks MR (specifically, the length along the traveling direction of the groove track GT) are all “a”. ing.

  In this case, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that searches the groove track GT in which the mark group MG shown in FIG. 4B is formed is the same as the recording mark MR and the recording mark ML. Due to reading in this order, “−” and “+” change. Therefore, bit data (bit 0) is read from a push-pull signal whose signal level changes in the order of “−” and “+”.

  As shown in FIG. 4C, the recording mark ML shifted by a predetermined distance to the left with respect to the track center and the recording mark MR shifted by a predetermined distance to the right with respect to the track center are the groove tracks GT. The mark groups MG arranged in this order along the traveling direction may be formed on the groove track GT as the mark group MG constituting the bit data (bit 1). FIG. 4C shows an example in which the lengths of the recording mark ML and the recording mark MR (specifically, the length along the traveling direction of the groove track GT) are all “a”. ing.

  In this case, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that searches the groove track GT in which the mark group MG shown in FIG. 4C is formed is the recording mark ML and the recording mark MR. Due to reading in this order, “+” and “−” change. Therefore, bit data (bit 1) is read from a push-pull signal whose signal level changes in the order of “+” and “−”.

  Note that the mark group MG shown in FIG. 4 (that is, the mark group MG constituting the synchronization data, the mark group MG constituting the bit data (bit 0), and the mark group MG constituting the bit data (bit 1)) is shown. Is just an example. Therefore, the synchronization data, the bit data (bit 0), and the bit data (bit 1) may be configured by using three types of mark groups MG showing modes other than the mode shown in FIG.

(2-2) Configuration of Mark Group Formed on Land Track Subsequently, with reference to FIGS. 5 and 6A to 6C, the land group of the mark group MG formed on the guide layer 12 will be described. The configuration of the mark group MG formed on the track LT will be described. FIG. 5 is a plan view showing a configuration of a pair of recording marks ML and MR constituting the mark group MG formed on the land track LT. FIG. 6A to FIG. 6C are plan views showing modes in which various types of data (specifically, bit data and synchronization data) are recorded by the mark group MG formed on the land track LT. is there.

  As shown in FIG. 5, the land track LT is formed with a pair of recording marks ML and MR 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) a recording mark ML shifted by a predetermined distance to the left side (for example, the left side with respect to the traveling direction of the land track GT) with respect to the track center of the land track LT. (Ii) A recording mark MR 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 is formed.

  The mark group MG formed on the land track LT is composed of such a pair of recording marks ML and MR. For example, FIG. 5 shows a mark group MG formed on the land track LT as a pair of recording marks ML and MR itself (that is, a single pair of recording marks ML and MR are combined). An example is shown. However, as described later with reference to FIG. 6 and the like, the mark group MG formed on the land track LT may be a mark group in which a plurality of pairs of recording marks ML and MR are combined. Alternatively, a plurality of pairs of recording marks ML and MR and one or more other recording marks (for example, other recording marks MC in which the center of the recording mark is positioned on the track center (FIGS. 4A to 4C) The mark group MG may be combined with a region where the recording mark is not formed (see FIG. 6A to FIG. 6C).

  In the present embodiment, the same mark group MG 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 mark group MG is adjacent or arranged along a direction (that is, a vertical direction in FIG. 5) orthogonal to the traveling direction of the land track LT (the direction from the left side to the right side in FIG. 5). As described above, each of the plurality of land tracks LT is formed. FIG. 5 shows three land tracks LT (that 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”). In this example, the mark group MG in which the recording mark ML and the recording mark MR are arranged in this order along the traveling direction of the land track LT is formed at the same rotational phase position.

  In particular, the same mark group MG is formed 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). The In other words, the number of the plurality of land tracks LT in which the same mark group MG 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, in FIG. 5, the same mark group MG (that is, the recording mark ML and the recording mark MR are arranged in this order along the traveling direction of the land track LT at the same rotational phase position of each of the three land tracks LT. The mark group MG) is formed.

  FIG. 5 shows an example of the mark group MG in which the recording marks ML and the recording marks MR are arranged in this order along the traveling direction of the land track LT. However, a mark group MG in which recording marks MR and recording marks ML are arranged in this order along the traveling direction of the land track LT may be used.

  In this embodiment, control 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 a mark group MG. More specifically, in this embodiment, bit data constituting part of the control information is recorded in advance on the guide layer 12 using the same mark group MG formed at the same rotational phase position. Therefore, one piece of control information can be obtained by combining (in other words, integrating) bit data obtained from a plurality of different mark groups MG formed at a plurality of locations on the guide layer 12. Furthermore, in this embodiment, using such a mark group MG, synchronization data for synchronization when reading bit data constituting at least part of the control information is recorded in the guide layer 12. However, arbitrary data may be recorded on the guide layer 12 using the mark group MG without being limited to the bit data and the synchronization data constituting at least a part of the control information.

  Specifically, as shown in FIG. 6A, a region where no recording mark is formed, a recording mark ML shifted to the left by a predetermined distance with respect to the track center, a region where no recording mark is formed, and a track A mark group MG in which recording marks MR shifted to the right by a predetermined distance with respect to the center are arranged in this order along the traveling direction of the land track LT is used as a mark group MG constituting synchronization data as a land track. It may be formed in LT. In FIG. 6A, the length of each of the region where the recording mark is not formed, the recording mark ML, and the recording mark MR (specifically, the length along the traveling direction of the land track LT) is all “ An example of “a” is shown.

  In this case, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that searches the land track LT on which the mark group MG shown in FIG. 6A is formed is an area where no recording mark is formed. The recording mark ML, the area where the recording mark is not formed, and the recording mark MR are read in this order, so that “0”, “+”, “0”, and “−” change. Therefore, the synchronization data is read from the push-pull signal whose signal level changes in the order of “0”, “+”, “0”, and “−”.

  As shown in FIG. 6B, the recording mark MR shifted by a predetermined distance to the right with respect to the track center and the recording mark ML shifted by a predetermined distance to the left with respect to the track center are the land tracks LT. The mark groups MG arranged in this order along the traveling direction may be formed on the land track LT as the mark group MG constituting the bit data (bit 0). FIG. 6B shows an example in which the respective lengths of the recording mark ML and the recording mark MR (specifically, the length along the traveling direction of the land track LT) are all “a”. ing.

  In this case, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that searches the land track LT on which the mark group MG shown in FIG. 6B is formed is the recording mark MR and the recording mark ML. Due to reading in this order, “−” and “+” change. Therefore, bit data (bit 0) is read from a push-pull signal whose signal level changes in the order of “−” and “+”.

  As shown in FIG. 6C, the recording mark ML shifted by a predetermined distance to the left with respect to the track center and the recording mark MR shifted by a predetermined distance to the right with respect to the track center are the land tracks LT. The mark group MG arranged in this order along the traveling direction may be formed on the land track LT as the mark group MG constituting the bit data (bit 1). FIG. 6C shows an example in which the respective lengths of the recording mark ML and the recording mark MR (specifically, the length along the traveling direction of the land track LT) are all “a”. ing.

  In this case, the signal level of the push-pull signal generated from the return light of the guide laser beam LB1 that searches the land track LT on which the mark group MG shown in FIG. 6C is formed is the recording mark ML and the recording mark MR. Due to reading in this order, “+” and “−” change. Therefore, bit data indicating bit 1 is read from the push-pull signal whose signal level changes in the order of “+” and “−”.

  Note that the mark group MG shown in FIG. 6 (that is, the mark group MG constituting the synchronization data, the mark group MG constituting the bit data (bit 0), and the mark group MG constituting the bit data (bit 1)) is shown. Is just an example. Therefore, the synchronization data, the bit data (bit 0), and the bit data (bit 1) may be configured by using three types of mark groups MG showing modes other than the mode shown in FIG.

  The mark group MG 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 recording marks MR and ML become concave portions, and therefore, when the optical disc 11 is manufactured, cutting using a cutting laser beam is performed at positions corresponding to the groove track GT and the mark group MG. That is, the cutting laser light is irradiated to the position corresponding to the groove track GT, the position corresponding to the recording mark MR, and the position corresponding to the recording mark ML. 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. For this reason, if the mark group MG formed on the land groove LT is formed at the same time as 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 GT). It is only necessary to switch the cutting laser light on and off at the time of formation). Therefore, the manufacturing process of the optical disk 11 can be simplified.

(2-3) Distribution Mode of Mark Group Next, the distribution mode of the mark group MG formed on the guide layer 12 will be described with reference to FIGS. FIG. 7 is a data structure diagram showing the data structure of the guide layer 12 (and also the recording layer 13). FIG. 8 is a plan view showing an example of the mark group MG formed in a specific slot. FIG. 9 is a plan view showing a mode in which a plurality of mark groups MG are recorded in a plurality of slots.

  As shown in FIG. 7, the recording layer 13 is divided in units of 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, control 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 83 groups. One group is subdivided into units of 8 slots. One slot has a size corresponding to 21 wobbles. 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.

  As shown in FIG. 8, the mark group MG indicating two synchronization data and four bit data is formed using 8 wobbles out of 15 wobbles. That is, in the example shown in FIG. 8, 4-bit bit data can be recorded in one slot. If it is allowed to use all 15 wobbles for recording bit data, a mark group MG indicating two synchronization data and eleven bit data can be formed in one slot. .

  As shown in FIG. 9, in this embodiment, using such a slot unit, different data groups MG are not formed at the same rotational phase position of the same groove track GT or the same land track LT. Configured as follows. Hereinafter, the mark group MG 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” will be referred to as a mark group MG (k) and the description will proceed. .

  As shown in FIG. 9, it is assumed that the mark group MG (k) is formed in the slot # 1. 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. Accordingly, 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.

  On the other hand, the mark group MG other than the mark group MG (k) is a 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”. 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. The group MG (k-4) to the mark group MG (k-1) and the mark group MG (k + 1) to the 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.

  For example, in FIG. 9, 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. 9 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. 9 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. 9 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. 9 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 rotation 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.

  Note that the shift amounts of the recording marks ML and MR from the track center may be unified in all the mark groups MG, or may be different for each mark group MG. For example, in the example shown in FIG. 9, the shift amounts from the track center of the recording marks ML and MR constituting the mark group MG (k) constitute mark groups MG other than the mark group MG (k). The shift amounts of the recording marks ML and MR from the track center may be the same or different. In short, it is sufficient that the shift amount from the track center of the recording marks ML and MR constituting the mark group MG is unified at least within the same mark group MG. For example, the shift amounts from the track center of the recording marks ML and MR constituting the mark group MG (k) need only be unified at least within the mark group MG (k).

(2-4) Characteristics of Mark Group Next, the characteristics of the mark group MG of this embodiment will be described.

  First, as described above, regardless of the formation of the mark group MG, the center of the beam spot of the guide laser beam LB1 and the track of the guide track TR are derived from the return beam of the guide laser beam LB1 searching on the guide track TR. A push-pull signal corresponding to the positional relationship with the center is obtained. As a result, tracking control based on the push-pull signal is performed.

  On the other hand, the signal level of the push-pull signal obtained from the return light of the guide laser beam LB1 that searches on the guide track TR on which the mark group MG is formed depends on the patterns of the recording marks ML and MR constituting the mark group MG. (See, for example, FIGS. 4A to 4C and FIGS. 6A to 6C). In other words, in the present embodiment, the signal level of the push-pull signal varies according to the positional relationship between the center of the beam spot of the guide laser beam LB1 and the recording marks constituting the mark group MG. However, since the mark group MG is a mark group MG in which a pair of recording marks ML and MR that are shifted equidistantly from the center of the track to the left and right are combined, the average value of the signal levels of the push-pull signal (in other words, the integration Value) is zero. Therefore, even if the mark group MG is formed on the guide track TR, the mark group MG has a large adverse effect on the tracking control based on the push-pull signal (for example, an adverse effect to the extent that normal tracking control cannot be performed). Little or no effect. Therefore, even if the mark group MG is formed on the guide track TR, suitable tracking control is performed in substantially the same manner as when the mark group MG is not formed on the guide track TR.

  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 the present embodiment, by forming the mark group MG in which the pair of recording marks ML and MR are combined on the guide layer 12, various data read using the push-pull signal can be recorded. In other words, in this embodiment, a mark group MG in which a pair of recording marks ML and MR are combined is formed on the guide layer 12, thereby recording various types of data that need not be read using the RF signal on the guide layer 12. be able to.

  Here, with reference to FIG. 10, an advantage realized by reading information indicated by the mark group MG formed on the guide layer 12 from a push-pull signal used for tracking control will be described. FIG. 10 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.

  As shown in FIG. 10, the signal level of the push-pull signal used for tracking control is the 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 control information that needs to be read using an RF signal is recorded 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.

  However, in this embodiment, control information that can be read using a push-pull signal originally used for tracking control is 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.

  For this reason, in this embodiment, the depth of the groove track GT (further, the depth of the recording marks ML, MR, and MC) may be set to less than λ / 6n. Thereby, since the signal characteristic of the push-pull signal becomes a preferable characteristic, tracking control is preferably performed and control information recorded on the guide layer 12 is preferably read using the mark group MG.

  Alternatively, the depth of the groove track GT (further, the depth of the recording marks ML, MR, and MC) may be set to less than λ / 8n. Thereby, since the signal characteristic of the push-pull signal becomes the best, the tracking control is more suitably performed, and the control information recorded on the guide layer 12 using the mark group MG is more suitably read.

  In addition, in the present embodiment, the same mark group MG is formed at the same rotational phase position of each of the plurality of groove tracks GT. Similarly, in the present embodiment, the same mark group MG is formed at the same rotational phase position of each of the plurality of land tracks LT. For this reason, the dependence of the guide laser beam LB1 on the focus deviation (focus offset) is weakened (specifically, the control information indicated by the mark group MG is preferably read even when the focus deviation increases). Can do. Hereinafter, with reference to FIG. 11 to FIG. 13A and FIG. 13B, the effect of reducing the dependency on the focus deviation will be described. FIG. 11 is a plan view showing a comparative example in which the mark group MG is formed on a single groove track GT. FIG. 12 is a graph showing the relationship between the focus deviation and the amplitude of the push-pull signal. FIGS. 13A and 13B 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 recording marks ML and MR.

  As shown in FIG. 11, it is assumed that a mark group MG is formed on a single groove track GT. At this time, the amplitude of the push-pull signal when the shift amounts from the track center of the pair of recording marks ML and MR constituting the mark group are set to four types of 100 nm, 220 nm, 320 nm, and 640 nm are shown in FIG. It becomes like this. As shown in FIG. 12, in the comparative example in which the mark group MG is formed on a single groove track GT, the push-pull signal increases as the focus deviation increases (for example, in the negative direction in FIG. 12). It can be seen that the amplitude of is small. As a result, tracking control is not suitably performed, and control information recorded on the guide layer 12 using the mark group MG may not be suitably read. It is assumed that this is because if the degree of defocus increases as the focus change increases, only one mark group MG cannot be suitably read.

  On the other hand, according to the present embodiment, since the same mark group MG 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 of the push-pull signal is 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 preferably performed, and control information recorded on the guide layer 12 is preferably read using the mark group MG.

  This is because the state of the beam spot of the guide laser beam LB1 when searching for the recording mark MR shifted to the right side with respect to the track center (see the state A1 in FIG. 13A) opens the tracking servo. 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 B1 in FIG. 13B) that is shifted leftward from the track center (shifted by about 270 ° in phase). Similarly, in the state of the beam spot of the guide laser beam LB1 when searching for the recording mark MR shifted to the left with respect to the track center (see the state A2 in FIG. 13A), the tracking servo is opened. This is substantially the same as the state of the beam spot of the guide laser beam LB1 (see state B2 in FIG. 13B) that is shifted to the right from the track center in the state (shifted by about 90 ° in phase). Therefore, the waveform of the push-pull signal obtained from the guide laser beam LB1 in the state shown in FIG. 13A 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. 13C). 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.

  Each of the techniques disclosed in the prior arts 2 to 6 described above is formed on a single recording track in order to record a single data on a single recording track as shown in FIG. It only shifts the recording pits or wobbles left and right. In other words, the techniques disclosed in the prior arts 2 to 6 described above 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 formed). This is different from this embodiment.

  In addition, according to the present embodiment, the mark group MG is formed on both the groove track GT and the land track LT. Therefore, the size of control information that can be recorded on the guide layer 12 can be increased as compared with an optical disc in which the mark group MG is formed on only one of the groove track GT and the land track LT. Furthermore, this makes it easier to read control information recorded on the guide layer 12 than an optical disc in which the mark group MG is formed only on one of the groove track GT and the land track LT.

  In addition, according to the present embodiment, the mark group MG constituting the synchronization data includes the recording mark MC located on the track center in addition to the pair of recording marks ML and MR. Even when the reference value (for example, zero level) of the signal level of the push-pull signal changes, the change of the signal level of the push-pull signal corresponding to the pair of recording marks ML and MR is preferably recognized. Can do. Hereinafter, with reference to FIGS. 14A and 14B, even if the reference value of the signal level of the push-pull signal varies, the push-pull corresponding to the pair of recording marks ML and MR. An advantage that the fluctuation of the signal level of the signal can be suitably recognized will be described. FIGS. 14A and 14B are graphs showing push-pull signals obtained from the mark group MG constituting the synchronization data including the pair of recording marks ML and MR and the recording mark MC located on the track center. It is.

  As shown in FIG. 14A, when the reference value of the signal level of the push-pull signal does not fluctuate, the signal of the push-pull signal corresponding to the pair of recording marks ML and MR is used by using a so-called default zero level. Level variations are preferably recognized.

  On the other hand, when the reference value of the signal level of the push-pull signal fluctuates (for example, shifts in the positive direction) as shown by the solid line on the left side of FIG. If the level is used, the signal level of the push-pull signal corresponding to the recording mark ML is different from the signal level of the push-pull signal corresponding to the recording mark MR. As a result, the reliability of reading the recording marks ML and MR based on the push-pull signal may deteriorate.

  However, in this embodiment, as shown by the dotted line on the right side of FIG. 14B, the signal level of the push-pull signal is determined using the signal level of the push-pull signal corresponding to the recording mark MC located on the track center. The reference value can be adjusted. Therefore, even when the reference value (for example, zero level) of the signal level of the push-pull signal changes, the change in the signal level of the push-pull signal corresponding to the pair of recording marks ML and MR is preferably recognized. can do.

(3) Modified Example Next, with reference to FIGS. 15 (a) to 15 (c) to 26 (a) to 26 (c), a modified example of the optical disk 11 of the present embodiment will be described. In the following, all correspond to modifications of the mark group MG.

(3-1) First Modification First, a first modification will be described with reference to FIGS. 15 (a) to 15 (c) and FIGS. 16 (a) to 16 (c). FIG. 15A to FIG. 15C are plan views showing a first modification example in which various types of data are recorded by the mark group MG formed on the groove track GT. FIG. 16A to FIG. 16C are plan views showing a first modified example of a mode in which various types of data are recorded by the mark group MG formed on the land track LT.

  As shown in FIGS. 15 (a) to 15 (c) and FIGS. 16 (a) to 16 (c), in the first modification, the lengths of the recording marks ML and MR constituting the synchronization data, and the bit data The lengths of the recording marks ML and MR constituting the same are different from each other. More specifically, as shown in FIGS. 15A and 16A, the lengths of the recording marks ML and MR constituting the synchronization data are “a”. On the other hand, as shown in FIGS. 15B and 15C and FIGS. 16B and 16C, the lengths of the recording marks ML and MR constituting the bit data are “2a”. .

  Alternatively, as shown in FIGS. 15A and 16A, also in the mark group MG constituting the synchronization data, the lengths of the recording marks ML and MR and the recording mark MC (particularly in the middle portion of the synchronization data). The length of the recording mark MC) and the area where the recording mark is not formed (particularly, the area where the recording mark located in the middle part of the synchronization data is not formed) may be different. More specifically, the length of each of the recording marks ML and MR may be “a”, and the length of the area where the recording mark MC and the recording mark are not formed may be different from “2a”. The mark group MG shown in FIGS. 15A and 16A includes the length of the recording mark MC located at the top portion of the synchronization data, the length of the recording mark MR located at the tail portion, and the synchronization data It can be said that this is an example in which the recording mark MC located in the middle portion and the length of the area where the recording mark is not formed are different.

  With this configuration, the synchronization data and bit data can be indicated by the lengths of the recording marks MR and ML and the lengths of the areas where the recording marks MC and recording marks are not formed. In other words, the synchronization data and bit data can be read from the lengths of the areas where the recording marks MR and ML and the recording marks MC and recording marks are not formed. Therefore, it is possible to relatively improve the reliability in reading synchronous data and bit data.

  The mark group MG shown in FIGS. 15A to 15C and FIGS. 16A to 16C is merely an example, and FIGS. 15A to 15C and FIG. Marks formed on the land track LT in a state where the lengths of the recording marks constituting the mark group MG formed on the groove track GT are different from each other in a mode other than the mode shown in FIGS. You may implement | achieve the state from which the length of the recording mark which comprises group MG differs.

(3-2) Second Modification Next, a second modification will be described with reference to FIGS. 17 (a) to 17 (c). FIGS. 17A to 17C are plan views showing a second modified example of a mode in which various types of data are recorded by the mark group MG formed on the land track LT.

  As shown in FIGS. 17A to 17C, in the second modified example, a pair of recording marks MR and ML constituting the synchronization data and bit data indicated by the mark group MG formed on the groove track GT. Is different from the pattern of the pair of recording marks MR and ML constituting the synchronization data and bit data indicated by the mark group MG formed on the land track LT.

  Specifically, the mark group MG formed on the groove track GT shows the synchronization data and the bit data in the same manner as in FIGS. 4A to 4C. That is, the mark group MG in which the recording mark MC, the recording mark ML, the recording mark MC, and the recording mark MR are arranged in this order indicates the synchronization data. That is, a push-pull signal whose signal level changes in the order of “0”, “+”, “0”, and “−” corresponds to the synchronization data. A mark group MG in which the recording mark MR and the recording mark ML are arranged in this order indicates bit data of bit 0. That is, a push-pull signal whose signal level changes in the order of “−” and “+” corresponds to bit data of bit 0. A mark group MG in which the recording mark ML and the recording mark MR are arranged in this order indicates bit data of bit 1. That is, a push-pull signal whose signal level changes in the order of “+” and “−” corresponds to bit data of bit 1.

  On the other hand, the mark group MG formed on the land track LT shows the synchronization data and the bit data in the manner shown in FIGS. 17 (a) to 17 (c). That is, an area where no recording mark is formed, a recording mark MR, an area where no recording mark is formed, and a mark group MG in which the recording marks ML are arranged in this order indicate synchronization data. That is, a push-pull signal whose signal level changes in the order of “0”, “−”, “0”, and “+” corresponds to the synchronization data. A mark group MG in which the recording mark ML and the recording mark MR are arranged in this order indicates bit data of bit 0. That is, a push-pull signal whose signal level changes in the order of “+” and “−” corresponds to bit data of bit 0. A mark group MG in which recording marks MR and recording marks ML are arranged in this order indicates bit data of bit 1. That is, a push-pull signal whose signal level changes in the order of “−” and “+” corresponds to bit data of bit 1.

  According to this structure, the mark group MG is formed on the groove track GT or formed on the land track LT depending on the pattern of the recording marks MR and ML and the area where the recording marks MC and recording marks are not formed. Whether the mark group is MG can be identified. Therefore, it is possible to relatively improve the reliability in reading synchronous data and bit data.

  The mark group MG shown in FIGS. 17A to 17C is merely an example, and is formed on the groove track GT in a mode other than the modes shown in FIGS. 17A to 17C. A state in which the pattern of the mark group MG formed and the pattern of the mark group MG formed on the land track LT are different may be realized.

(3-3) Third Modification Next, a third modification will be described with reference to FIGS. 18 (a) to 18 (c). FIGS. 18A to 18C are plan views showing a third modified example of a mode in which various types of data are recorded by the mark group MG formed on the land track LT.

  As shown in FIGS. 18A to 18C, in the third modified example, the lengths of the pair of recording marks MR and ML constituting the mark group MG formed on the groove track GT, and the land track LT. The lengths of the pair of recording marks MR and ML constituting the mark group MG formed thereon are different.

  Specifically, the mark group MG formed on the groove track GT shows the synchronization data and the bit data in the same manner as in FIG. That is, the lengths of the recording marks MC, the recording marks ML, and the recording marks MR constituting the mark group MG formed on the groove track GT are all “a”.

  On the other hand, the mark group MG formed on the land track LT shows synchronous data and bit data in the manner shown in FIG. That is, the lengths of the recording marks MR and the recording marks ML constituting the mark group MG formed on the land track LT are both “2a”.

  With this configuration, it is possible to identify whether the mark group MG is formed on the groove track GT or the mark group MG formed on the land track LT based on the lengths of the recording marks MR and ML. Therefore, it is possible to relatively improve the reliability in reading synchronous data and bit data.

  The mark group MG shown in FIGS. 18A to 18C is merely an example, and is formed on the groove track GT in a mode other than the modes shown in FIGS. 18A to 18C. A state in which the length of the recording mark constituting the mark group MG and the length of the recording mark constituting the mark group MG formed on the land track LT may be realized.

(3-4) Fourth Modified Example Next, a fourth modified example will be described with reference to FIGS. 19 (a) to 19 (c) and FIGS. 20 (a) to 20 (c). FIG. 19A to FIG. 19C are plan views showing a fourth modification example in which various types of data are recorded by the mark group MG formed on the groove track GT. FIG. 20A to FIG. 20C are plan views showing a fourth modification of the aspect in which various types of data are recorded by the mark group MG formed on the land track LT.

  As shown in FIGS. 19 (a) to 19 (c), in the fourth modification, the pattern of the mark group MG formed on the groove track GT is the above-described FIGS. 4 (a) to 4 (c). This is different from the pattern of the mark group MG described with reference to FIG. For example, in the fourth modification, the recording mark MC positioned on the track center is used to indicate bit data instead of indicating synchronous data. Further, in the fourth modified example, for example, as in the first modified example, the length of the pair of recording marks ML and MR constituting the synchronization data and the length of the pair of recording marks ML and MR constituting the bit data are as follows. Is different.

  Specifically, as shown in FIG. 19A, a recording mark ML shifted to the left by a predetermined distance with respect to the track center, and a recording mark MR shifted to the right by a predetermined distance with respect to the track center. However, the mark group MG arranged in this order along the traveling direction of the groove track GT may be recorded on the groove track GT as the mark group MG constituting the synchronization data. FIG. 19A shows an example in which the lengths of the recording mark ML and the recording mark MR are all “2a”.

  As shown in FIG. 19B, the recording mark MC positioned on the track center, the recording mark MR shifted to the right by a predetermined distance with respect to the track center, and the left by a predetermined distance with respect to the track center. Are recorded on the groove track GT as a mark group MG constituting bit data indicating bit 0. The mark group MG is arranged in this order along the traveling direction of the groove track GT. Also good. FIG. 19B shows an example in which the lengths of the recording mark MC, the recording mark ML, and the recording mark MR are all “a”. FIG. 19B shows an example in which the recording mark MC is arranged before the recording mark MR (that is, the top portion of the bit data). However, the recording mark MC may be arranged between the recording mark MR and the recording mark ML (that is, the middle part of the bit data), or arranged behind the recording mark ML (that is, the tail part of the bit data). May be.

  As shown in FIG. 19C, the recording mark MC located on the track center, the recording mark ML 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 mark group MG in which the recording marks MR are arranged in this order along the traveling direction of the groove track GT is recorded on the groove track GT as a mark group MG constituting bit data indicating bit 1. Also good. FIG. 19C shows an example in which the lengths of the recording mark MC, the recording mark ML, and the recording mark MR are all “a”. FIG. 19C shows an example in which the recording mark MC is arranged in front of the recording mark ML (that is, the top portion of the bit data). However, the recording mark MC may be arranged between the recording mark ML and the recording mark MR (that is, the middle part of the bit data) or arranged behind the recording mark MR (that is, the tail part of the bit data). May be.

  As shown in FIGS. 20A to 20C, in the fourth modified example, the pattern of the mark group MG formed on the land track LT is the same as that of FIGS. 6A to 6C described above. This is different from the pattern of the mark group MG described with reference to FIG. For example, in the fourth modification, an area where no recording mark is formed is used to indicate bit data instead of indicating synchronous data. Further, in the fourth modified example, for example, as in the first modified example, the length of the pair of recording marks ML and MR constituting the synchronization data and the length of the pair of recording marks ML and MR constituting the bit data are as follows. Is different.

  Specifically, as shown in FIG. 20A, a recording mark ML shifted to the left by a predetermined distance with respect to the track center, and a recording mark MR shifted to the right by a predetermined distance with respect to the track center. However, the mark group MG arranged in this order along the traveling direction of the land track LT may be recorded on the land track LT as the mark group MG constituting the synchronization data. FIG. 20A shows an example in which the lengths of the recording mark ML and the recording mark MR are all “2a”.

  As shown in FIG. 20B, an area where no recording mark is formed, a recording mark MR shifted to the right by a predetermined distance with respect to the track center, and a recording shifted by a predetermined distance to the left with respect to the track center. A mark group MG in which marks ML are arranged in this order along the traveling direction of the land track LT may be recorded on the land track LT as a mark group MG constituting bit data indicating bit 0. Note that FIG. 20B shows an example in which the area where the recording mark is not formed and the lengths of the recording mark ML and the recording mark MR are all “a”. FIG. 20B shows an example in which the area where the recording mark is not formed is arranged in front of the recording mark MR (that is, the top portion of the bit data). However, the region where the recording mark is not formed may be arranged between the recording mark MR and the recording mark ML (that is, the middle portion of the bit data), or behind the recording mark ML (that is, the tail portion of the bit data). ) May be arranged.

  As shown in FIG. 20 (c), an area where no recording mark is formed, a recording mark ML shifted to the left by a predetermined distance from the track center, and a recording shifted by a predetermined distance to the right from the track center. A mark group MG in which marks MR are arranged in this order along the traveling direction of the land track LT may be recorded on the land track LT as a mark group MG constituting bit data indicating bit 1. FIG. 20C shows an example in which the area where the recording mark is not formed and the lengths of the recording mark ML and the recording mark MR are all “a”. FIG. 20C shows an example in which the area where the recording mark is not formed is arranged in front of the recording mark ML (that is, the top portion of the bit data). However, the region where the recording mark is not formed may be arranged between the recording mark ML and the recording mark MR (that is, the middle portion of the bit data), or behind the recording mark MR (that is, the tail portion of the bit data). ) May be arranged.

  Even if comprised in this way, the reliability in reading synchronous data or bit data can be relatively improved as in the first modification. In addition, since the recording mark MC or the area where the recording mark is not formed is arranged at the top part of the data bit (that is, the signal level of the push-pull signal corresponding to the top part of the data bit becomes zero), the bit data The separation becomes clear.

  The mark group MG shown in FIGS. 19A to 19C and 20A to 20C is merely an example, and FIGS. 19A to 19C and FIG. The mark group MG may be formed in a mode other than the mode shown in 20 (a) to 20 (c).

(3-5) Fifth Modification Next, a fifth modification will be described with reference to FIGS. 21 (a) to 21 (c) and FIGS. 22 (a) to 22 (c). FIG. 21A to FIG. 21C are plan views showing a fifth modification example in which various types of data are recorded by the mark group MG formed on the groove track GT. FIG. 22A to FIG. 22C are plan views showing a fifth modified example of a mode in which many types of data are recorded by the mark group MG formed on the land track LT.

  As shown in FIGS. 21 (a) to 21 (c), in the fifth modification, the above-described groove track GT is positioned above the groove track GT in which the mark group MG is to be formed. The recorded marks ML and MR are not formed. In other words, according to the embodiment shown in FIGS. 4A to 4C, the condensing of the guide laser beam LB1 when searching the mark group MG among the plurality of groove tracks GT on which the mark group MG is to be formed. The recording marks ML and MR described above are not formed on the groove track GT designated as the position. For example, the mark group MG (k) is assigned to the groove track GT having the track number “k−2”, the groove track GT having the track number “k”, and the groove track GT having the track number “k + 2”. Assume the state to be formed. In this case, according to the fifth modification, the mark group MG (k) is formed on each of the groove track GT having the track number “k−2” and the groove track GT having the track number “k + 2”. On the other hand, the mark group MG (k) is not formed on the groove track GT whose track number is “k”.

  Similarly, as shown in FIGS. 22 (a) to 22 (c), in the fifth modification, on the land track LT positioned at the most center among the plurality of land tracks LT on which the mark group MG is to be formed. The above-described recording marks ML and MR are not formed. In other words, according to the mode shown in FIGS. 6A to 6C, the condensing of the guide laser beam LB1 when searching the mark group MG among the plurality of land tracks GT on which the mark group MG is to be formed. The recording marks ML and MR described above are not formed on the land track LT designated as the position. For example, mark group MG (k + 1) is assigned to each of land track LT with track number “k−1”, land track LT with track number “k + 1”, and land track LT with track number “k + 3”. Assume the state to be formed. In this case, according to the fifth modification, the mark group MG (k + 1) is formed on each of the land track LT with the track number “k−1” and the land track LT with the track number “k + 3”. On the other hand, the mark group MG (k + 1) is not formed on the land track LT whose track number is “k + 1”.

  With this configuration, since the number of recording marks MR and ML to be formed on the guide layer 12 is relatively reduced, the manufacturing process of the optical disc 11 can be simplified.

(3-6) Sixth Modification Subsequently, a sixth modification will be described with reference to FIGS. 23 (a) to 23 (g). FIG. 23A to FIG. 23G are plan views showing a sixth modification of the aspect in which many types of data are recorded by the mark group MG formed on the groove track GT.

  As shown in FIGS. 23A to 23G, in the sixth modification, the number of recording marks ML and MR constituting the mark group MG is the same. FIG. 23A to FIG. 23G show examples of the mark group MG indicating seven types of bit data while satisfying the condition that the numbers of the recording marks ML and MR are the same.

  FIG. 23A to FIG. 23G show a mode in which various types of data are recorded by the mark group MG formed on the groove track GT. However, even when many types of data are recorded by the mark group MG formed on the land track LT, the number of recording marks ML and MR constituting the mark group MG is the same. It is preferred that

  If comprised in this way, the average value (in other words, integral value) of the fluctuation | variation of the signal level of a push pull signal will be zero. Therefore, even if the mark group MG is formed on the guide track TR, the mark group MG has little or no adverse effect on the tracking control based on the push-pull signal. Therefore, even if the mark group MG is formed on the guide track TR, suitable tracking control is performed in substantially the same manner as when the mark group MG is not formed on the guide track TR.

(3-7) Seventh Modification Next, a seventh modification will be described with reference to FIGS. 24 (a) and 24 (b). FIG. 24A and FIG. 24B are plan views showing a seventh modification of the aspect in which many types of data are recorded by the mark group MG formed on the groove track GT.

  As shown in FIGS. 24A and 24B, in the seventh modification, a pair of recording marks MR and ML are arranged in the top portion and the tail portion of bit data, respectively, and then the two pairs are recorded. The bit data of bit 0 and the bit data of bit 1 are distinguished depending on whether or not a pair of recording marks MR and ML are arranged in an area between the recording marks MR and ML (that is, the middle portion of the bit data). The Specifically, as shown in FIG. 24A, a mark group MG in which a pair of recording marks MR and ML are not arranged in an area between two pairs of recording marks MR and ML is bit data of bit 0. Configure. On the other hand, as shown in FIG. 24B, a mark group MG in which a pair of recording marks MR and ML are arranged in an area sandwiched between two pairs of recording marks MR and ML constitutes bit 1 bit data. To do.

  Even with this configuration, the reliability in reading bit data can be relatively improved.

(3-8) Eighth Modification Next, with reference to FIG. 25, an eighth modification will be described. FIG. 25 is a plan view showing an eighth modification of the aspect in which many types of data are recorded by the mark group MG formed on the groove track GT.

  As shown in FIG. 25, in the eighth modification, synchronous data is arranged both before and after 4-bit bit data, and then a pair of recording marks MR and ML in an area between the two synchronous data. The bit data of bit 0 and the bit data of bit 1 are distinguished depending on whether or not is arranged. Specifically, as shown in FIG. 25, a portion where a pair of recording marks MR and ML in an area between two synchronization data is not arranged constitutes bit 0 bit data. On the other hand, as shown in FIG. 25, a portion where a pair of recording marks MR and ML are arranged in an area between two synchronization data forms bit 1 bit data.

  Even with this configuration, the reliability in reading bit data can be relatively improved. In addition, according to the eighth modification, bit data of bit 0 can be represented without using a pair of recording marks ML and MR. Therefore, the mark group MG indicating the bit data of bit 0 does not affect the fluctuation of the signal level of the push-pull signal. Therefore, even if the mark group MG is formed on the guide track TR, the possibility that the mark group MG has a great adverse effect on tracking control based on the push-pull signal can be further reduced. Therefore, even if the mark group MG is formed on the guide track TR, much more suitable tracking control is performed as in the case where the mark group MG is not formed on the guide track TR.

(3-9) Ninth Modification Next, with reference to FIGS. 26A to 26C, a ninth modification will be described. FIG. 26A to FIG. 26C are plan views showing a ninth modification example in which various types of data are recorded by the mark group MG formed on the land track LT.

  As shown in FIGS. 26A to 26C, in the ninth modification, the mark group MG formed on the landmark LT is formed simultaneously with the formation of the landmark LT.

  In the above description, the mark group MG formed on the landmark LT is formed simultaneously with the formation of the groove track GT in order to simplify the manufacturing process of the optical disc 11. However, in order to exhibit the effect of recording control information on the guide layer 12 using the mark group MG, as shown in the ninth modification, the mark group MG formed on the landmark LT is a land group. It may be formed at the same time when the mark LT is formed.

(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.

(4-1) Configuration of Recording / Reproducing Device First, the configuration of the recording / reproducing device 100 of this embodiment will be described with reference to FIG. FIG. 27 is a block diagram showing the configuration of the recording / reproducing apparatus 100 of the present embodiment.

  As shown in FIG. 27, 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. 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.

  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.

  The optical pickup 102 includes a red semiconductor laser light source that emits guide laser light LB1, a blue semiconductor laser light source that emits recording / reproducing laser light 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. 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.

  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 caused by the return light. Based on this push-pull signal, tracking control and reading of bit data according to the mark group MG 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.

  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.

  Next, a more detailed configuration of the signal recording / playback unit 103 will be described with reference to FIG. FIG. 28 is a block diagram showing a configuration of the signal recording / reproducing unit 103.

  As shown in FIG. 28, 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 detects the mark group MG formed on the guide layer 12 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). To do. More specifically, the mark group detection circuit 130 detects the mark group MG by monitoring fluctuations in the signal level of the push-pull signal output from the guide light receiving element, and also includes the synchronization data indicated by the mark group MG and Bit Data Detection To detect such a mark group MG, the mark group detection circuit 130 includes an LPF (Low Path Filter) 131, an LPF 132, an S / H (Sample Hold) circuit 133, and an S / H A circuit 134, a comparator 135, a synchronous data detector 136, a bit data detector 137, a memory 138, and a reproduction timing generation unit 139 are provided.

  The push-pull signal output from the guide light receiving element is input to both LPFs 131 and 132.

  The LPF 131 is a filter for removing the noise of the push-pull signal, for example, a filter having a cutoff frequency through which a waveform of a frequency due to the mark group MG passes. The push-pull signal that has passed through the LPF 131 is sampled and held by the S / H circuit 133 at every predetermined timing. The push-pull signal (that is, the signal level) sampled and held in the S / H circuit 133 is input to the comparator 135. Note that the signal level of the push-pull signal sampled and held in the S / H circuit 133 can vary depending on the pattern of the mark group MG.

  On the other hand, the LPF 132 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 132 is sampled and held at a predetermined timing in the S / H circuit 134. The push-pull signal (that is, the signal level) sampled and held in the S / H circuit 134 is input to the comparator 135. Note that the push-pull signal (that is, the signal level) sampled and held in the S / H circuit 134 corresponds to a reference value of the signal level of the push-pull signal (so-called zero level, see FIG. 14).

  The comparator 135 compares the signal level of the push-pull signal sampled and held in the S / H circuit 133 with the signal level of the push-pull signal sampled and held in the S / H circuit 134. More specifically, for example, the comparator 135 determines whether or not the difference between the signal level of the push-pull signal that varies according to the pattern of the mark group MG and the reference value of the push-pull signal is greater than or equal to a threshold value. . As a result, the comparator 135 determines whether the signal level of the push-pull signal is “0”, “+”, or “−”.

  The synchronization data detector 136 detects synchronization data based on the comparison result in the comparator 135. That is, the synchronization data detector 136 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 135.

  The bit data detector 137 detects bit data based on the comparison result in the comparator 135. That is, the bit data detector 137 detects bit data by detecting a push-pull signal whose signal level varies in a manner corresponding to bit data based on the comparison result in the comparator 135. As described above, the bit data appears following the synchronization data. Therefore, the bit data detector 137 may start the operation of detecting the bit data after the synchronous data is detected by the synchronous data detector 136.

  The memory 138 temporarily stores bit data detected by the bit data detector 137. The bit data stored in the memory 138 is input to the CPU 111 as appropriate. As a result, the CPU 111 acquires control information (for example, address information, clock information, recording start timing information, etc.) by combining a plurality of bit data detected by the mark group detection circuit 130.

  The reproduction timing generation unit 139 defines the timing at which the S / H circuit 133, the S / H circuit 134, the comparator 135, the synchronous data detector 136, and the bit data detector 137 operate. Specifically, the recording is performed so that the fluctuation of the signal level of the push-pull signal is monitored at an appropriate timing according to the length of the recording marks MC, ML, and MR (or the length of the mark group MG). The S / H circuit 133, the S / H circuit 134, the comparator and 135, and the synchronization data detection are performed at an appropriate timing according to the lengths of the marks MC, ML and MR (or the length of the mark group MG). To the device 136 and the bit data detector 137.

(4-2) Flow of Operation of Recording / Reproducing Device Next, the flow of operation of the recording / reproducing device 100 of this embodiment will be described with reference to FIGS.

(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. 29 is a flowchart showing an overall flow of the operation of the recording / reproducing apparatus 100 of the present embodiment.

  As shown in FIG. 29, when the optical disk 11 is loaded onto the recording / reproducing apparatus 100 (step S10), 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 beam LB1 based on the push-pull signal generated from the return light of the guide laser beam LB1 (step S20). 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 S20).

  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 control information such as address information, clock information, and recording start timing information.

  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 S30).

  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 S40).

  As a result of the determination in step S40, when it is determined that a recording operation on the desired recording layer 13 is performed (step S40: Yes), the recording / reproducing apparatus 100 performs a recording operation (step S50). The recording operation performed by the recording / reproducing apparatus 100 will be described in detail later with reference to FIG.

  On the other hand, as a result of the determination in step S40, when it is determined that the recording operation for the desired recording layer 13 is not performed (step S40: No), the CPU 111 determines the desired recording of the plurality of recording layers 13. It is determined whether or not the reproducing operation for the layer 13 is performed (step S60).

  As a result of the determination in step S60, when it is determined that the reproduction operation for the desired recording layer 13 is performed (step S60: Yes), the recording / reproducing apparatus 100 performs the reproduction operation (step S70). The reproduction operation performed by the recording / reproducing apparatus 100 will be described in detail later with reference to FIG.

  On the other hand, as a result of the determination in step S60, when it is determined that the reproducing operation for the desired recording layer 13 is not performed (step S60: No), the recording / reproducing apparatus 100 may end the operation.

(4-2-2) Flow of Recording Operation Next, with reference to FIG. 30, the flow of the recording operation (step S50 in FIG. 29) of the recording / reproducing apparatus 100 of the present embodiment will be described. FIG. 30 is a flowchart showing the flow of the recording operation (step S50 in FIG. 29) of the recording / reproducing apparatus 100 of this embodiment.

  As shown in FIG. 30, 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 region on the guide layer 12 indicated by the desired address information (step). S51). 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.

  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 S52).

  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 S53).

  Further, the CPU 111 acquires clock information and recording start timing information obtained by combining the bit data detected by the mark group detection circuit 130 (step S54).

  Thereafter, the CPU 111 determines whether or not the current timing matches the recording start timing information acquired in step S54 (step S55).

  As a result of the determination in step S55, when it is determined that the current timing does not match the recording start timing information (step S55: No), the CPU 111 continues the determination in step S55.

  On the other hand, if it is determined that the current timing coincides with the recording start timing information as a result of the determination in step S55 (step S55: Yes), the CPU 111 synchronizes with the clock information acquired in step S550. The optical pickup 102 and the signal recording / reproducing unit 103 are controlled to perform the recording operation on the recording layer 13 (step S56). As a result, the record information is recorded on the desired recording layer 13.

  Thereafter, the CPU 111 determines whether or not to end the recording operation (step S57). 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.

  As a result of the determination in step S57, if it is determined not to end the recording operation (step S57: No), the CPU 111 continues the recording operation.

  On the other hand, if it is determined in step S57 that the recording operation is to be terminated (step S57: Yes), the CPU 111 updates the management information to reflect the current recording operation. Thereafter, the recording / reproducing apparatus 100 ends the recording operation.

(4-2-3) Flow of Reproducing Operation Next, with reference to FIG. 31, the flow of the reproducing operation (step S70 in FIG. 29) of the recording / reproducing apparatus 100 of the present embodiment will be described. FIG. 31 is a flowchart showing the flow of the reproducing operation (step S70 in FIG. 29) of the recording / reproducing apparatus 100 of this embodiment.

  As shown in FIG. 31, 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 region on the guide layer 12 indicated by the desired address information (step). S71). 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 reproduction operation is to be started.

  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 S72).

  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, the tracking control of the recording / reproducing laser beam LB2 is performed (step S73). 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.

  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 S76). As a result, the recorded information recorded on the desired recording layer 13 is reproduced.

  Thereafter, the CPU 111 determines whether or not to end the recording operation (step S77). 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.

  As a result of the determination in step S77, when it is determined not to end the reproduction operation (step S77: No), the CPU 111 continues the reproduction operation.

  On the other hand, as a result of the determination in step S770, when it is determined that the reproduction operation is to be ended (step S77: Yes), the recording / reproducing apparatus 100 ends the reproduction operation.

  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. .

  29 to 31 illustrate an example in which the recording / reproducing apparatus 100 performs both the recording operation and the reproducing operation. 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).

  Further, the present invention can be appropriately changed without departing from the gist or the idea of the invention which can be read from the claims and the entire specification, and a recording / reproducing apparatus accompanied with such a change is also included in the technical idea of the invention. included.

DESCRIPTION OF SYMBOLS 11 Optical disk 12 Guide layer 13 Recording layer 102 Optical pick-up 103 Signal recording / reproducing part 111 CPU
120 Tracking control circuit 130 Mark group detection circuit 136 Synchronization data detector 137 Bit data detector GT Groove track LT Land track MG Mark group ML, MR, MC Recording mark LB1 Guide laser beam LB2 Recording / reproducing laser beam

Claims (17)

(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 laser beam irradiated to the guide layer is placed at the same rotational phase position of each of at least two guide tracks included in the beam spot formed on the guide layer. A recording / reproducing apparatus that performs at least one of a recording operation and a reproducing operation on a recording medium on which the same mark group is formed by combining a pair of recording marks shifted by a predetermined distance from side to side with respect to the center of the track. And
Based on a push-pull signal obtained from the return light of the guide laser light from the guide layer, reading means for reading bit data corresponding to the mark group;
A recording / reproducing apparatus comprising: a recording / reproducing unit that performs at least one of the recording operation and the reproducing operation on the plurality of recording layers based on the bit data read by the reading unit.   The recording / reproducing apparatus according to claim 1, wherein the reading unit reads the bit data corresponding to a combination of the pair of recording marks constituting the mark group.   2. The recording / reproducing according to claim 1, wherein the reading unit reads the bit data based on a level fluctuation of the push-pull signal according to a combination of the pair of recording marks constituting the mark group. apparatus.   2. The depth of the pair of recording marks is less than λ / 6n (where λ is the wavelength of the guide laser beam and n is a substrate refractive index of the recording medium). Recording and playback device.   2. The depth of the pair of recording marks is λ / 8n (where λ is the wavelength of the guide laser beam and n is the refractive index of the substrate of the recording medium). Recording / playback device.   The recording / reproducing apparatus according to claim 1, wherein the same mark group is formed at the same rotational phase position of each of the plurality of guide tracks.   2. The same mark group is formed at the same rotational phase position of each of the other guide tracks excluding at least one guide track located near the center of the plurality of guide tracks. The recording / reproducing apparatus described in 1. The same mark group in which the pair of recording marks are combined is formed at the same rotational phase position of each of the other guide tracks excluding at least one guide track located on the outermost side of the plurality of guide tracks. And
At the same rotational phase position of the at least one guide track located at the outermost side, the predetermined distance shift in the center direction of the beam spot with reference to the track center of the at least one guide track instead of the pair of recording marks 2. The recording / reproducing apparatus according to claim 1, wherein a mark group is formed by combining a single recording mark. The mark group includes (i) a mark group in which the pair of recording marks are combined, and (ii) another pair of recording marks located on the track center of the pair of recording marks and the respective guide tracks. Including a group of marks,
The reading means reads the bit data by identifying the signal level of the push-pull signal corresponding to the pair of recording marks on the basis of the signal level of the push-pull signal corresponding to the other recording mark. The recording / reproducing apparatus according to claim 1. The mark group in which the pair of recording marks is combined is a mark group indicating predetermined bit data to be recorded on the guide layer,
The mark group in which the pair of recording marks and other recording marks located on the track center are combined is a mark group indicating synchronization data used for synchronization when reading the bit data. The recording / reproducing apparatus according to claim 9.   The mark group is formed by combining the pair of recording marks so that an average value of a signal level of a push-pull signal obtained by irradiating the guide laser beam to the mark group becomes zero. The recording / reproducing apparatus according to claim 1.   The mark group is formed such that the number of recording marks shifted to the left with respect to the track center is equal to the number of recording marks shifted to the right with respect to the track center. The recording / reproducing apparatus according to claim 1, wherein: A plurality of different mark groups are discretely formed at a plurality of locations on the recording medium,
The recording / reproducing means performs at least one of the recording operation and the reproducing operation on the plurality of recording layers based on control information obtained by combining a plurality of bit data corresponding to the plurality of different mark groups. The recording / reproducing apparatus according to claim 1.   One mark group formed at the same phase position of each of the plurality of guide tracks including one guide track as a center includes each of the plurality of guide tracks including another guide track different from the one guide track. 2. The recording / reproducing apparatus according to claim 1, wherein the recording / reproducing apparatus is formed at a rotational phase position different from other mark groups formed at the same rotational phase position. The guide track includes a groove track and a land track formed alternately,
A mark group is formed at the same phase position of each of the plurality of groove tracks included in the beam spot by combining a pair of recording marks shifted by a predetermined distance from side to side with respect to the track center of each groove track. Has been
A mark group is formed at the same phase position of each of the plurality of land tracks included in the beam spot by combining a pair of recording marks shifted by a predetermined distance from side to side with respect to the track center of each land track. The recording / reproducing apparatus according to claim 1, wherein:   16. The recording / reproducing apparatus according to claim 15, wherein the mark group formed on the land track is formed as a mark group formed simultaneously when two groove tracks adjacent to the land track are formed. . (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 laser beam irradiated to the guide layer is placed at the same rotational phase position of each of at least two guide tracks included in the beam spot formed on the guide layer. A recording / reproducing method for performing at least one of a recording operation and a reproducing operation on a recording medium on which the same mark group is formed by combining a pair of recording marks shifted by a predetermined distance from side to side with respect to the center of the track. And
Based on a push-pull signal obtained from the return light of the guide laser light from the guide layer, a reading process of reading bit data corresponding to the mark group;
A recording / reproducing method comprising: a recording / reproducing step of performing at least one of the recording operation and the reproducing operation on the plurality of recording layers based on the bit data read by the reading step.

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