JP3561245B2 - Optical disk, optical disk reproducing device, optical disk reproducing method, optical disk recording device, and optical disk recording method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disc having a recording track formed by alternately arranging groove tracks and land tracks in a radial direction. Further, the present invention relates to an optical disk reproducing apparatus and an optical disk reproducing method for reproducing information from such an optical disk. Further, the present invention relates to an optical disk recording device and an optical disk recording method for recording information on such an optical disk.
[0002]
[Prior art]
A DVD-RAM is known as an example of a rewritable optical disk using a phase change recording method. This optical disk has spirally provided guide grooves that are discontinuous at a constant period, and both inside the grooves (groove tracks) and between the grooves (land tracks) are used as recording tracks. The discontinuous portion of the guide groove is radially aligned, and header data is recorded in the discontinuous portion by pre-pits. A section from the head of the header data to the head of the next header data in the track direction is called one sector. Recording and reproduction of information on and from the optical disk are performed in sector units. At the time of recording / reproducing data on the optical disk, the address data contained in the header data is read, and information is recorded on a subsequent track by a phase change recording mark, or a phase change already recorded on a subsequent sector. Recording marks are reproduced.
[0003]
In a DVD-RAM, header data is recorded in discontinuous portions of guide grooves on the extension of a boundary between a groove track and a land track which are adjacent to each other, and this header data is used for recording / reproducing processing on both tracks. You. The effect of crosstalk generated when reproducing header data (pre-pits) is greater than the effect of crosstalk generated when reproducing phase change recording marks. Therefore, the header data is zigzag-recorded at every one track pitch in the radial direction, and as a result, the header data recording pitch in the radial direction is wider than one track pitch. When the light beam is scanned on the recording track, in the discontinuous portion of the guide groove, the header data arranged on one boundary extension of the track and the header data arranged on the other boundary extension of the track are sequentially arranged. Will be played. At this time, by comparing the levels of the reproduced signals of the two header data, it is possible to detect the deviation of the track scanning. Subsequently, a tracking error signal affected by the groove is obtained from the continuous portion of the guide groove. An off-track can be detected from the tracking error signal.
[0004]
[Problems to be solved by the invention]
However, as described above, since the guide groove is discontinuous in the header data recording portion, there is a problem that a tracking error signal cannot be obtained in the header data recording portion. When a plurality of sectors are continuously reproduced, the recording position of the header data can be predicted to some extent. Therefore, when scanning the header data recording portion, the scanning operation can be appropriately continued by interrupting the track servo while maintaining the level of the tracking error signal obtained immediately before. However, at the time of track search, the recording position of the header data cannot be predicted. For this reason, if a track search is accidentally attempted on the header data recording portion, the off-track and the retry of the track search are repeated, and as a result, a great amount of time is required to access the target sector. Will be done.
[0005]
A technique for solving such a problem is disclosed in Japanese Patent Application No. 2000-303855. In brief, the header data is recorded by changing the wall position at one boundary between the adjacent groove track and land track. Thereby, all the guide grooves can be made continuous. Therefore, even if a track search is attempted on the header data recording portion, a tracking error signal affected by the guide groove can be obtained. However, the wall positions at the boundaries at both ends of the track are not changed, only the wall positions at one boundary of the track are changed. For this reason, it is not possible to detect the deviation of track scanning from the reproduction signal at the header recording position.
[0006]
In recent years, development of an optical disc having a plurality of rewritable information recording layers stacked thereon has been promoted. In such an optical disc, information can be recorded and reproduced independently for each recording layer. If each recording layer has header data such as the DVD-RAM described above, the discontinuous portion of the track on which the header data is recorded affects the recording and reproduction of other layers. As described above, the header data is recorded in a zigzag manner at every track pitch in the radial direction, but the discontinuous portions of the track are substantially aligned in the radial direction (the discontinuous portions of the track are All together). The continuous part and the discontinuous part of the track in each recording layer do not always coincide with the optical axis direction of the light beam. In other words, when data is recorded or reproduced by irradiating a light beam on a track of a certain recording layer, even when the light transmittance or light reflectance of a continuous portion of the track of another recording layer is affected. If there is, there may be a case where the light transmittance or the light reflectance of the discontinuous portion of the track of another recording layer is affected. As a result, a problem occurs in the reliability of data recording and reproduction.
[0007]
An object of the present invention, which has been made in view of the above circumstances, is to provide the following optical disk, optical disk reproducing device, optical disk reproducing method, optical disk recording device, and optical disk recording method.
[0008]
(1) An optical disc that is configured to be able to obtain a tracking error signal from a header data recording position and that is capable of detecting deviation in track scanning.
[0009]
(2) An optical disc having a plurality of recording layers capable of reducing loss of recording / reproducing reliability.
[0010]
(3) an optical disk reproducing apparatus for reproducing a header data from an optical disk configured to be able to obtain a tracking error signal from a recording position of the header data and configured to detect deviation of track scanning; and Optical disc playback method.
[0011]
(4) The header data is reproduced from an optical disc configured so that a tracking error signal can be obtained from the recording position of the header data, and the deviation of the track scanning can be detected. An optical disk recording device and an optical disk recording method for recording data.
[0012]
[Means for Solving the Problems]
In order to solve the above problems and achieve the object, an optical disk, an optical disk reproducing device, an optical disk reproducing method, an optical disk recording device, and an optical disk recording method of the present invention are configured as follows.
[0013]
(1) An optical disk of the present invention is an optical disk having an information recording surface, wherein the information recording surface has a recording track formed by alternately arranging groove tracks and land tracks in a radial direction. The recording track has a plurality of uneven boundary walls, each of which is arranged at a position which is sequentially shifted by a predetermined distance with respect to a direction along the track, on a part of the boundary wall of each track; The wall is formed by irregularities on which header data including address data is reflected.
[0014]
(2) The optical disc of the present invention has a plurality of the information recording surfaces.
[0015]
(3) The optical disc reproducing apparatus of the present invention includes a reproducing means for reproducing header data from the uneven boundary wall.
[0016]
(4) The optical disk reproducing method of the present invention reproduces header data from the uneven boundary wall.
[0017]
(5) An optical disk recording apparatus according to the present invention, wherein: reproducing means for reproducing header data from the uneven boundary wall; and recording means for recording target information in a target recording field provided in a recording track based on the reproduced header data. And
[0018]
(6) The optical disk recording method of the present invention reproduces header data from the uneven boundary wall, and records target information in a target recording field provided in a recording track based on the reproduced header data.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0020]
FIG. 1 is a diagram schematically showing a header area of an optical disc according to the present invention.
[0021]
The optical disk of the present invention has one or a plurality of information recording surfaces, and the information recording surface has a recording track of a single spiral structure in which a land track and a groove track are switched every one round. That is, this optical disc has a recording track formed by alternately arranging land tracks and groove tracks in the radial direction. Then, data is recorded on both tracks.
[0022]
As shown in FIG. 1, an uneven boundary wall W1 is arranged on a part of a boundary wall between a land track LT1 and a groove track GT1 adjacent to the land track LT1. An uneven boundary wall W2 is arranged on a part of the boundary wall between the groove track GT1 and the land track LT2 adjacent to the groove track GT1. An uneven boundary wall W3 is arranged on a part of the boundary wall between the land track LT2 and the groove track GT2 adjacent to the land track LT2. An uneven boundary wall W4 is arranged on a part of the boundary wall between the groove track GT2 and the land track LT3 adjacent to the groove track GT2.
[0023]
The uneven boundary walls W1 to W4 are formed by unevenness on which header data including address data is reflected. The uneven boundary wall W2 is arranged at a position shifted from the W1 by one length of the uneven boundary wall in the direction along the track. Similarly, the uneven boundary wall W3 is arranged at a position shifted from the W2 by one length of the uneven boundary wall in the direction along the track. Similarly, the uneven boundary wall W4 is arranged at a position shifted from the W3 by one length of the uneven boundary wall in the direction along the track. That is, the uneven boundary walls W1 to W4 are arranged at positions that are sequentially shifted by the length of one uneven boundary wall with respect to the direction along the track.
[0024]
When the light beam scans on the groove track GT1, the uneven boundary walls W2 and W1 form one header section 101, the uneven boundary wall W2 forms the first half header section 103, and the uneven boundary wall W1 forms the second half header section 104. Become. When the light beam scans over the land track LT2, the uneven boundary walls W3 and W2 form one header section 101, the uneven boundary wall W3 forms the first half header section 103, and the uneven boundary wall W2 forms the second half header section 104. Become. When the light beam scans on the groove track GT2, the uneven boundary walls W4 and W3 form one header section 101, the uneven boundary wall W4 forms the first half header section 103, and the uneven boundary wall W3 forms the second half header section 104. Become.
[0025]
The unevenness forming the uneven boundary wall W1 includes header data relating to a recording field (data portion 102) arranged on the groove track GT1. The irregularities forming the irregular boundary wall W2 include header data relating to a recording field (data section 102) arranged on the land track LT2. The unevenness forming the uneven boundary wall W3 includes header data relating to a recording field (data portion 102) arranged on the groove track GW2. The unevenness forming the uneven boundary wall W4 includes header data relating to a recording field (data portion 102) arranged on the land track LT3.
[0026]
One sector is formed by the header section 101 and the subsequent data section 102. That is, the header section 102 is arranged at the head of each sector, and the header section 102 stores the address data of the subsequent data section.
[0027]
The above-mentioned uneven boundary wall is formed by making the boundary wall position between the groove track and the land track uneven on both track sides. The concavo-convex boundary walls W2 and W4 are formed such that the boundary wall position where the inner peripheral side is a land track and the outer peripheral side is a groove track is concave and convex on both track sides. On the other hand, the concavo-convex boundary walls W1 and W3 are formed such that the boundary wall position where the outer peripheral side is a land track and the inner peripheral side is a groove track is uneven on both track sides.
[0028]
With the above-described configuration, tracks formed on the optical disc of the present invention are continuous even at the position where the header section 101 is arranged. Therefore, when the light beam is scanned along the track formed on the optical disk of the present invention, a tracking error signal can be obtained from any position, and the off-track can be detected accurately.
[0029]
In order to manufacture an optical disk having the above-described track structure, for example, two beams are used for exposing the master of the optical disk. The two beams are arranged at a slightly shifted interval in the radial direction, and two beams having a predetermined power are simultaneously irradiated at the time of exposure of a groove track as a recording track. When the header portion 101 is formed, the intensity of the light beam located on the land side of the two beams is made higher than a predetermined power at the timing of extending the boundary wall to the land side, and the timing of extending the boundary wall to the groove side. The intensity of the light beam located on the groove side of the two beams is made lower than a predetermined power.
[0030]
In this way, a part of the boundary wall between the land track and the groove track is made uneven on both track sides to form an uneven boundary wall. When reproducing a certain track, the optical disc device can obtain a reproduction signal corresponding to an uneven boundary wall formed at a boundary between the certain track and a track adjacent to the certain track. In the case of a conventional DVD-RAM, header data is recorded by pre-pits on an extended line between a groove track and a land track. For this reason, the polarity of the reproduction signal on which the pre-pits are reflected is the same between the case where the same pre-pit is reproduced along the land track and the case where the same pre-pit is reproduced along the groove track. In the case of the optical disk of the present invention, the polarity of the reproduced signal reflecting the uneven boundary wall is reversed between the case where the same uneven boundary wall is reproduced along the land track and the case where the same uneven boundary wall is reproduced along the groove track. become. Therefore, in order to read a reproduced signal on which the uneven boundary wall is reflected, it is necessary to switch the polarity.
[0031]
In FIG. 1, the header data is reflected by the position of the portion of the uneven boundary wall projecting toward the land side. This corresponds to pit position recording when information is recorded in pits. Also, the header data is reflected by the position of the portion protruding toward the land on both the boundary between the inner track and the adjacent track and the boundary between the outer track and the adjacent track. Therefore, the polarity of the reproduced signal becomes the same when reproducing either header data. As described above, such a disc can be manufactured by making the relationship between the intensity of the beam intensity during exposure of the master disc and the polarity of the recording signal the same for two beams.
[0032]
FIG. 2 is a diagram illustrating a reproduced signal of the header data reflected on the uneven boundary wall shown in FIG.
[0033]
When the light beam for reproduction scans the center of the groove track, as shown in FIG. 2A, the signal amplitude of the first half header is equal to the signal amplitude of the second half header. When the inner circumference side of the groove track is scanned, as shown in FIG. 2B, the signal amplitude of the first half header decreases and the signal amplitude of the second half header increases. Conversely, when the outer circumference side of the groove track is scanned, as shown in FIG. 2C, the signal amplitude of the first half header increases and the signal amplitude of the second half header decreases. That is, by comparing the reproduction signal amplitude of the first half header with the reproduction signal amplitude of the second half header, it is possible to detect the tracking shift amount of the reproduction light. By feeding back this detection result, the center of the track can be scanned. When scanning a land track, the signal polarity of the portion protruding to the land side is opposite to that during groove track scanning. Further, the magnitude relationship between the reproduced signal amplitude of the first half header and the reproduced signal amplitude of the second half header and the directional relationship of the tracking error are also reversed.
[0034]
As a method of reproducing the uneven boundary wall of the optical disk according to the present invention, there is a method of separately detecting left and right reflected light amounts along a track and calculating a difference between left and right reflected light amounts. In this case, as shown in FIG. 1, if the header data is recorded at the position of the portion protruding toward the land track on both the inner boundary wall and the outer boundary wall, the reproduction signal The polarity is reversed in the first and second half headers. In order to cope with the optical disk device, it is necessary to switch the polarity of the reproduction signal. By reversing the polarity of the beam intensity at the time of master exposure with two beams, one boundary side of the groove track is the position of the part protruding toward the land, and the other boundary side is the position of the part protruding toward the groove side. Records the header data. When the header data is recorded at the position of the overhanging portion, the ratio of the unevenness on the boundary wall corresponding to the first half header and the unevenness on the boundary wall corresponding to the second half header paired with the first half header are not equal. In other words, if the header data is reversed before and after, even if the polarity is the same when the reproduced signal is detected by the difference, some correction means is required to detect the tracking deviation from the comparison of the amplitude of the reproduced signal. Become.
[0035]
Although the case of pit position recording has been described above, the header data may be reflected by the change position from the concave portion to the convex portion and the change position from the convex portion to the concave portion of the uneven boundary wall. In other words, the header data may be reflected by the position of the change point from the land side to the groove side of the uneven boundary wall and the position of the change point from the groove side to the land side. This corresponds to pit edge recording when information is recorded in pits. Edge recording is advantageous in that the amount of information per fixed length can be increased as compared with position recording, and that the ratio of unevenness on the left and right becomes equal because the signal polarity is symmetric. On the other hand, it is required to accurately form an edge position in consideration of the relationship with the profile of the reproduction beam.
[0036]
In the above description, the first half header is arranged on the boundary wall where the inner circumference side is a groove track and the outer circumference side is a land track, and the second half header is arranged on the boundary wall where the inner circumference side is a land track and the outer circumference side is a groove track. Although the case has been described, the present invention is not limited to this. In other words, the second half header is arranged on the boundary wall where the inner track is the groove track and the outer track is the land track, and the first header is arranged on the border wall where the inner track is the land track and the outer track is the groove track. Is also good.
[0037]
Further, although the description has been made assuming that the header data is reflected by the position of the portion protruding to the land track side, the present invention is not limited to this. That is, the header data may be reflected according to the position of the portion protruding toward the groove track. In the first place, the relationship between the land track and the groove track is relative, and may be reversed in the disc manufacturing process. Therefore, the present invention can be implemented even if the land and the groove in the above description are reversed.
[0038]
Subsequently, an optical disc including a plurality of recording layers having the above-described header will be described with reference to FIGS. As shown in FIG. 3, the optical disc 1 has a plurality of recording layers. When viewed from the incident light side, the optical disc 1 has a first recording layer 202 on the near side, a transparent layer 204 on the back, and a second recording layer 203 on the back. These first recording layer 202 and second recording layer 204 have a header structure shown in FIG. The light beam 205 for recording and reproduction is focused on one of the first and second recording layers by moving the position of the objective lens 8 (see FIG. 5) up and down.
[0039]
As shown in FIG. 4A, when the light beam is focused on the first recording layer 202, the reflected light from the first recording layer 202 includes the reflected light from the second recording layer 203. Superimposed. Further, as shown in FIG. 4B, when the light beam is focused on the second recording layer 203, the reflected light from the second recording layer 203 includes the reflected light from the first recording layer 202. Not only the light is superimposed, but also the transmittance of the first recording layer 202 affects. As is clear from FIGS. 4A and 4B, when a light beam is focused on a target recording layer to be recorded / reproduced, the light beam is focused on another recording layer. Instead, the light beam spreads on the other recording layers. In an optical disc having a plurality of recording layers, if there is an area having a different transmittance or reflectance in a part of the recording layer, the reliability of recording / reproducing with respect to a target recording layer is impaired. Such adverse effects can be reduced to some extent if regions having different transmittances and reflectivities are locally present. The header of the optical disk of the present invention shown in FIG. 1 is gradually shifted in the track direction. On the other hand, in a conventional optical disk, discontinuous portions of tracks are connected in a radial direction. In other words, it can be said that the optical disc of the present invention locally has regions having different transmittances and reflectivities as compared with the conventional optical disc. Therefore, according to the optical disk having a plurality of recording layers according to the present invention, the degree to which the reliability is impaired in recording and reproduction on any recording layer is reduced.
[0040]
FIG. 5 is a diagram showing a schematic configuration of an optical disk device according to an example of the present invention. This optical disk apparatus records target data on the optical disk 1 having the above-described uneven boundary wall as a header, and reproduces data recorded on the optical disk 1. The optical disc 1 may have a plurality of recording layers as described above.
[0041]
As shown in FIG. 4, the optical disc device includes a modulation circuit 2, a laser control circuit 3, a laser 4, a collimating lens 5, a polarizing beam splitter (PBS) 6, a quarter-wave plate 7, an objective lens 8, and a condenser. It includes a lens 9, a photodetector 10, a signal processing circuit 11, a demodulation circuit 12, a focus error signal generation circuit 13, a tracking error signal generation circuit 14, a header detection circuit 15, a focus control circuit 16, and a tracking control circuit 17.
[0042]
First, data recording by this optical disk device will be described. The recording data (data symbol) is modulated by the modulation circuit 2 into a predetermined channel bit sequence. The channel bit sequence corresponding to the recording data is converted by the laser control circuit 3 into a laser drive waveform. The laser control circuit 3 drives the laser 4 with a pulse to record data corresponding to a desired bit sequence on the optical disc 1. The recording light beam emitted from the laser 4 is converted into parallel light by the collimating lens 5, enters the PBS 6, and transmits. The beam transmitted through the PBS 6 passes through the quarter-wave plate 7 and is focused on the information recording surface of the optical disc 1 by the objective lens 8. The focused beam is maintained in a state where the best minute spot is obtained on the recording surface by the focus control by the focus control circuit 16 and the tracking control by the tracking control circuit 17. When the optical disc 1 has a plurality of recording layers, the focus control circuit 16 focuses the light beam on the target recording layer.
[0043]
Next, reproduction of data by the optical disk device will be described. Based on the data reproduction instruction, the laser 4 emits a light beam for reproduction. The light beam for reproduction emitted from the laser 4 is converted into parallel light by the collimator lens 5, enters the PBS 6, and transmits. The light beam transmitted through the PBS 6 is transmitted through the quarter-wave plate 7 and is focused on the information recording surface of the optical disk 1 by the objective lens 8. The focused beam is maintained in a state where the best minute spot is obtained on the recording surface by the focus control by the focus control circuit 16 and the tracking control by the tracking control circuit 17. At this time, the reproducing light beam irradiated on the optical disk 1 is reflected by the reflective film or the reflective recording film in the information recording surface. The reflected light passes through the objective lens 8 in the opposite direction, and becomes parallel light again. The reflected light passes through the quarter-wave plate 7, has polarization perpendicular to the incident light, and is reflected by the PBS 6. The beam reflected by the PBS 6 is converged by the condenser lens 9 and is incident on the photodetector 10. The photodetector 10 is composed of, for example, a four-divided photodetector. The light beam incident on the photodetector 10 is photoelectrically converted into an electric signal and amplified. The amplified signal is equalized and binarized by the signal processing circuit 11 and sent to the demodulation circuit 12. The demodulation circuit 12 performs a demodulation operation corresponding to a predetermined modulation method, and outputs reproduced data.
[0044]
Further, a focus error signal is generated by the focus error signal generation circuit 13 based on a part of the electric signal output from the photodetector 10. Similarly, a tracking error signal generation circuit 14 generates a tracking error signal based on a part of the electric signal output from the photodetector 10. The focus control circuit 16 controls the focus of the beam spot based on the focus error signal. The tracking control circuit 17 controls the tracking of the beam spot based on the tracking error signal.
[0045]
Further, the header is detected by the header detection circuit 15 based on the electric signal output from the photodetector 10. That is, the header detection circuit 15 detects the uneven boundary wall on which the header data is reflected. The reproduction data output from the demodulation circuit 12 at the timing when the header is detected by the header detection circuit 15 is the header data. Based on the header data, the target data is reproduced from the target recording field, or the target data is recorded in the target recording field. The header detection circuit 15 also detects the header detection state described in FIG. That is, the reproduction signal level of the header data reflected in the first half header section 103 and the reproduction signal level of the header data reflected in the second half header section 104 are compared to detect a track shift of the reproduction light beam. The tracking control circuit 17 controls the tracking of the beam spot based on the detection result so as to scan the center of the track.
[0046]
It should be noted that the present invention is not limited to the above-described embodiment, and can be variously modified in an implementation stage without departing from the spirit of the invention. In addition, the embodiments may be implemented in appropriate combinations as much as possible. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriate combinations of a plurality of disclosed constituent elements. For example, even if some components are deleted from all the components shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effects described in the column of the effect of the invention can be solved. Is obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.
[0047]
【The invention's effect】
According to the present invention, the following optical disk, optical disk reproducing device, optical disk reproducing method, optical disk recording device, and optical disk recording method can be provided.
[0048]
(1) An optical disc that is configured to be able to obtain a tracking error signal from a header data recording position and that is capable of detecting deviation in track scanning.
[0049]
(2) An optical disc having a plurality of recording layers capable of reducing loss of recording / reproducing reliability.
[0050]
(3) an optical disk reproducing apparatus for reproducing a header data from an optical disk configured to be able to obtain a tracking error signal from a recording position of the header data and configured to detect deviation of track scanning; and Optical disc playback method.
[0051]
(4) The header data is reproduced from an optical disc configured so that a tracking error signal can be obtained from the recording position of the header data, and the deviation of the track scanning can be detected. An optical disk recording device and an optical disk recording method for recording data.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a header area of an optical disc according to the present invention.
FIG. 2 is a diagram illustrating a reproduced signal of header data reflected on an uneven boundary wall shown in FIG. 1;
FIG. 3 is a diagram schematically showing an optical disc provided with a plurality of recording layers according to the present invention.
FIG. 4 is a diagram for describing reflected light when a light beam is applied to an optical disc having a plurality of recording layers.
FIG. 5 is a block diagram illustrating a schematic configuration of an optical disc device according to an example of the present invention.
[Explanation of symbols]
1: Optical disk
2 ... Modulation circuit
3. Laser control circuit
4 ... Laser
5 ... Collimating lens
6 ... Polarizing beam splitter (PBS)
7 ... quarter wave plate
8 Objective lens
9 ... Condensing lens
10. Photodetector
11 ... Signal processing circuit
12 Demodulation circuit
13: Focus error signal generation circuit
14. Tracking error signal generation circuit
15 ... Header detection circuit
16 Focus control circuit
17. Tracking control circuit
101: Header section
102: Data section
103: First half header
104: Second half header
LT1, LT2, LT3 ... land track
GT1, GT2 ... Groove track
W1, W2, W3, W4...

Claims (12)

An optical disc having an information recording surface,
The information recording surface has a recording track formed by alternately arranging groove tracks and land tracks in the radial direction,
The recording track ,
A first uneven boundary wall disposed on a part of a boundary wall between the first land track and a first groove track adjacent to the first land track;
A second uneven boundary wall disposed on a part of a boundary wall between the first groove track and a second land track adjacent to the first groove track;
A third uneven boundary wall disposed on a part of a boundary wall between the second land track and a second groove track adjacent to the second land track;
A fourth uneven boundary wall arranged on a part of a boundary wall between the second groove track and a third land track adjacent to the second groove track;
Has,
The first, second, third, and fourth uneven boundary walls are formed by unevenness reflecting header data including address data,
The first, second, third, and fourth uneven boundary walls are arranged at positions sequentially shifted by one length of the uneven boundary wall with respect to the direction along the track,
For the first groove track, the first uneven boundary wall is defined as a second half header, the second uneven boundary wall is defined as a first half header,
For the second land track, the second uneven boundary wall is defined as a second half header, the third uneven boundary wall is defined as a first half header,
For the second groove track, the third uneven boundary wall is defined as a second half header, the fourth uneven boundary wall is defined as a first half header,
The inner peripheral side of the second half header defined for the first and second groove tracks is a groove track, the outer peripheral side is a land track,
The inner peripheral side of the second half header defined for the third land track is a land track, the outer peripheral side is a groove track,
One sector is formed by the first and second uneven boundary walls and the recording field of the first groove track, and header data for a recording field included in this sector is defined as the second half header. Included in the uneven boundary wall,
One sector is formed by the second and third uneven boundary walls and the recording field of the second land track, and the header data for the recording field included in this sector is defined as the second half header. Included in the uneven boundary wall,
One sector is formed by the third and fourth uneven boundary walls and the recording field of the second groove track, and the header data for the recording field included in this sector is defined as the second half header. Included in the uneven boundary wall,
An optical disc characterized by the above-mentioned.   The header data is reflected by the position of one of the concave and convex portions of the first, second, third, and fourth uneven boundary walls,
  The optical disk according to claim 1, wherein:   The header data is reflected by changing positions of the concave and convex portions of the first, second, third, and fourth uneven boundary walls,
  The optical disk according to claim 1, wherein:   The optical disc according to claim 1, wherein the optical disc has a plurality of information recording surfaces.   An optical disc reproducing apparatus for reproducing information from an optical disc,
  The optical disc has an information recording surface,
  The information recording surface has a recording track formed by alternately arranging groove tracks and land tracks in the radial direction,
  The recording track,
  A first uneven boundary wall disposed on a part of a boundary wall between the first land track and a first groove track adjacent to the first land track;
  A second uneven boundary wall disposed on a part of a boundary wall between the first groove track and a second land track adjacent to the first groove track;
  A third uneven boundary wall disposed on a part of a boundary wall between the second land track and a second groove track adjacent to the second land track;
  A fourth uneven boundary wall arranged on a part of a boundary wall between the second groove track and a third land track adjacent to the second groove track;
  Has,
  The first, second, third, and fourth uneven boundary walls are formed by unevenness reflecting header data including address data,
  The first, second, third, and fourth uneven boundary walls are arranged at positions sequentially shifted by one length of the uneven boundary wall with respect to the direction along the track,
  For the first groove track, the first uneven boundary wall is defined as a second half header, the second uneven boundary wall is defined as a first half header,
  For the second land track, the second uneven boundary wall is defined as a second half header, the third uneven boundary wall is defined as a first half header,
  For the second groove track, the third uneven boundary wall is defined as a second half header, the fourth uneven boundary wall is defined as a first half header,
  The inner peripheral side of the second half header defined for the first and second groove tracks is a groove track, the outer peripheral side is a land track,
  The inner peripheral side of the second half header defined for the third land track is a land track, the outer peripheral side is a groove track,
  One sector is formed by the first and second uneven boundary walls and the recording field of the first groove track, and the header data for the recording field included in this sector is defined as the second half header. Included in the uneven boundary wall,
  One sector is formed by the second and third uneven boundary walls and the recording field of the second land track, and the header data for the recording field included in this sector is defined as the second half header. Included in the uneven boundary wall,
  One sector is formed by the third and fourth uneven boundary walls and the recording field of the second groove track, and the header data for the recording field included in this sector is defined as the second half header. Included in the uneven boundary wall,
  This optical disc playback device,
  From the first uneven boundary wall defined as a second half header of the first groove track, a sector formed by the first and second uneven boundary walls and a recording field of the first groove track. The header data is reproduced, and the second and third uneven boundary walls and the recording field of the second land track are defined from the second uneven boundary wall defined as the second half header of the second land track. The header data for the sector formed by the second groove track is reproduced from the third uneven boundary wall defined as the second half header of the second groove track, and the third and fourth uneven boundary walls and the second A reproducing means for reproducing header data for a sector formed by the recording field of the groove track.   Compare the reproduction signal level of the header data reflected on the two uneven boundary walls located on a part of the boundary wall on both sides of the predetermined track and shifted by a predetermined distance with respect to the direction along the track. 6. The optical disk reproducing apparatus according to claim 5, further comprising a track deviation detecting means for detecting a track deviation of the reproduction light beam with respect to the predetermined track.   An optical disc reproducing method for reproducing information from an optical disc, comprising:
  The optical disc has an information recording surface,
  The information recording surface has a recording track formed by alternately arranging groove tracks and land tracks in the radial direction,
  The recording track,
  A first uneven boundary wall disposed on a part of a boundary wall between the first land track and a first groove track adjacent to the first land track;
  A second uneven boundary wall disposed on a part of a boundary wall between the first groove track and a second land track adjacent to the first groove track;
  A third uneven boundary wall disposed on a part of a boundary wall between the second land track and a second groove track adjacent to the second land track;
  A fourth uneven boundary wall arranged on a part of a boundary wall between the second groove track and a third land track adjacent to the second groove track;
  Has,
  The first, second, third, and fourth uneven boundary walls are formed by unevenness reflecting header data including address data,
  The first, second, third, and fourth uneven boundary walls are arranged at positions sequentially shifted by one length of the uneven boundary wall with respect to the direction along the track,
  For the first groove track, the first uneven boundary wall is defined as a second half header, the second uneven boundary wall is defined as a first half header,
  For the second land track, the second uneven boundary wall is defined as a second half header, the third uneven boundary wall is defined as a first half header,
  For the second groove track, the third uneven boundary wall is defined as a second half header, the fourth uneven boundary wall is defined as a first half header,
  The inner peripheral side of the second half header defined for the first and second groove tracks is a groove track, the outer peripheral side is a land track,
  The inner peripheral side of the second half header defined for the third land track is a land track, the outer peripheral side is a groove track,
  One sector is formed by the first and second uneven boundary walls and the recording field of the first groove track, and the header data for the recording field included in this sector is defined as the second half header. Included in the uneven boundary wall,
  One sector is formed by the second and third uneven boundary walls and the recording field of the second land track, and the header data for the recording field included in this sector is defined as the second half header. Included in the uneven boundary wall,
  One sector is formed by the third and fourth uneven boundary walls and the recording field of the second groove track, and the header data for the recording field included in this sector is defined as the second half header. Included in the uneven boundary wall,
  This optical disc playback method is
  From the first uneven boundary wall defined as a second half header of the first groove track, a sector formed by the first and second uneven boundary walls and a recording field of the first groove track. The header data is reproduced, and the second and third uneven boundary walls and the recording field of the second land track are defined from the second uneven boundary wall defined as the second half header of the second land track. The header data for the sector formed by the second groove track is reproduced from the third uneven boundary wall defined as the second half header of the second groove track, and the third and fourth uneven boundary walls and the second The header data for the sector formed by the recording field of the groove track is reproduced.   The reproduction signal levels of the header data reflected on the two uneven boundary walls located on a part of the boundary wall on both sides of the predetermined track and displaced by a predetermined distance from the direction along the track are compared. 8. The optical disk reproducing method according to claim 7, wherein a track shift of the reproducing light beam with respect to a predetermined track is detected.   An optical disk recording device that records information on an optical disk,
  The optical disc has an information recording surface,
  The information recording surface has a recording track formed by alternately arranging groove tracks and land tracks in the radial direction,
  The recording track,
  A first uneven boundary wall disposed on a part of a boundary wall between the first land track and a first groove track adjacent to the first land track;
  A second uneven boundary wall disposed on a part of a boundary wall between the first groove track and a second land track adjacent to the first groove track;
  A third uneven boundary wall disposed on a part of a boundary wall between the second land track and a second groove track adjacent to the second land track;
  A fourth uneven boundary wall arranged on a part of a boundary wall between the second groove track and a third land track adjacent to the second groove track;
  Has,
  The first, second, third, and fourth uneven boundary walls are formed by unevenness reflecting header data including address data,
  The first, second, third, and fourth uneven boundary walls are arranged at positions sequentially shifted by one length of the uneven boundary wall with respect to the direction along the track,
  For the first groove track, the first uneven boundary wall is defined as a second half header, the second uneven boundary wall is defined as a first half header,
  For the second land track, the second uneven boundary wall is defined as a second half header, the third uneven boundary wall is defined as a first half header,
  For the second groove track, the third uneven boundary wall is defined as a second half header, the fourth uneven boundary wall is defined as a first half header,
  The inner peripheral side of the second half header defined for the first and second groove tracks is a groove track, the outer peripheral side is a land track,
  The inner peripheral side of the second half header defined for the third land track is a land track, the outer peripheral side is a groove track,
  One sector is formed by the first and second uneven boundary walls and the recording field of the first groove track, and the header data for the recording field included in this sector is defined as the second half header. Included in the uneven boundary wall,
  One sector is formed by the second and third uneven boundary walls and the recording field of the second land track, and the header data for the recording field included in this sector is defined as the second half header. Included in the uneven boundary wall,
  One sector is formed by the third and fourth uneven boundary walls and the recording field of the second groove track, and the header data for the recording field included in this sector is defined as the second half header. Included in the uneven boundary wall,
  This optical disk recording device
  From the first uneven boundary wall defined as a second half header of the first groove track, a sector formed by the first and second uneven boundary walls and a recording field of the first groove track. The header data is reproduced, and the second and third uneven boundary walls and the recording field of the second land track are defined from the second uneven boundary wall defined as the second half header of the second land track. Reproduces the header data for the sector formed by the second groove track, and defines the second half header of the second groove track. Reproducing means for reproducing, from the third uneven boundary wall, header data for a sector formed by the third and fourth uneven boundary walls and the recording field of the second groove track;
  Recording means for recording target information in a target recording field based on the header data reproduced by the reproducing means,
  It is characterized by having.   The reproduction signal levels of the header data reflected on the two uneven boundary walls located on a part of the boundary wall on both sides of the predetermined track and displaced by a predetermined distance from the direction along the track are compared. 10. The optical disk recording apparatus according to claim 9, further comprising: a track shift detecting means for detecting a track shift of the reproduction light beam with respect to a predetermined track.   An optical disc recording method for recording information on an optical disc, comprising:
  The optical disc has an information recording surface,
  The information recording surface has a recording track formed by alternately arranging groove tracks and land tracks in the radial direction,
  The recording track,
  A first uneven boundary wall disposed on a part of a boundary wall between the first land track and a first groove track adjacent to the first land track;
  A second uneven boundary wall disposed on a part of a boundary wall between the first groove track and a second land track adjacent to the first groove track;
  A third uneven boundary wall disposed on a part of a boundary wall between the second land track and a second groove track adjacent to the second land track;
  A fourth uneven boundary wall arranged on a part of a boundary wall between the second groove track and a third land track adjacent to the second groove track;
  Has,
  The first, second, third, and fourth uneven boundary walls are formed by unevenness reflecting header data including address data,
  The first, second, third, and fourth uneven boundary walls are arranged at positions sequentially shifted by one length of the uneven boundary wall with respect to the direction along the track,
  For the first groove track, the first uneven boundary wall is defined as a second half header, the second uneven boundary wall is defined as a first half header,
  For the second land track, the second uneven boundary wall is defined as a second half header, the third uneven boundary wall is defined as a first half header,
  For the second groove track, the third uneven boundary wall is defined as a second half header, the fourth uneven boundary wall is defined as a first half header,
  The inner peripheral side of the second half header defined for the first and second groove tracks is a groove track, the outer peripheral side is a land track,
  The inner peripheral side of the second half header defined for the third land track is a land track, the outer peripheral side is a groove track,
  One sector is formed by the first and second uneven boundary walls and the recording field of the first groove track, and the header data for the recording field included in this sector is defined as the second half header. Included in the uneven boundary wall,
  One sector is formed by the second and third uneven boundary walls and the recording field of the second land track, and the header data for the recording field included in this sector is defined as the second half header. Included in the uneven boundary wall,
  One sector is formed by the third and fourth uneven boundary walls and the recording field of the second groove track, and the header data for the recording field included in this sector is defined as the second half header. Included in the uneven boundary wall,
  This optical disk recording method
  From the first uneven boundary wall defined as the second half header of the first groove track to the sector formed by the first and second uneven boundary walls and the recording field of the first groove track. Reproducing the header data from the second uneven boundary wall defined as the second half header of the second land track, from the second and third uneven boundary wall, and the recording field of the second land track; The header data for the sector formed by the second groove track is reproduced from the third uneven boundary wall defined as the second half header of the second groove track, and the third and fourth uneven boundary walls and the second Reproduction of the header data for the sector formed by the recording field of the groove track of
  Based on the reproduced header data, record target information in a target recording field,
  It is characterized by the following.   The reproduction signal levels of the header data reflected on the two uneven boundary walls located on a part of the boundary wall on both sides of the predetermined track and displaced by a predetermined distance in the direction along the track are compared. 12. The optical disk recording method according to claim 11, wherein a track deviation of a reproduction light beam with respect to a predetermined track is detected.

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