CN100378834C - CD - Google Patents

Abstract

An optical disc (D) alternately provided with a plurality of grooves (G) and a plurality of lands (L), wherein the structure of the address data recording area is formed on the two side walls of the groove (G). A pair of oscillating parts (31a, 31b) of phase. Thus, a push-pull signal with a large amplitude can be obtained, which is beneficial to increase the data recording density.

Description

CD

technical field

The invention relates to an optical disc. The "optical disk" referred to in this specification refers to an optical disk that can record and/or reproduce data by using an optical device, and is a broad concept, excluding CD-ROMs and other read-only optical disks in a narrow sense. In addition, it also includes a type of optical disc in which data can be written by using a magneto-optical recording method, a phase change method, or an organic photochromic method.

Background technique

As for optical disks, high density is being developed. If an example of optical disks is to be given, AS-MO (Advanced Storage Magneto-Optical Disk) is the specification of the optical disks. The optical disk of this specification is a single side with a diameter of 120mm, and has a storage capacity of about 6GB. As shown in FIG. 7, the magneto-optical magnetic disk forms tracks by alternately forming grooves G (Groove) and lands L (Land) in the radial direction (arrow Ra direction). On each track, there are provided areas for forming a plurality of precise time marks 70 at constant intervals in the circumferential direction of the magneto-optical disk, so that each track is divided into a plurality of segments by each area. As these plural segments, there are address segments 8 and data segments 9 , and one frame includes one address segment 8 and thirty-eight data segments 9 . The data segment 9 is an area where the user records data by magneto-optical recording, while the address segment 8 is an area where address data such as a track address is recorded.

As shown in FIG. 8 , the recording area of the magneto-optical disk is divided into a plurality of zones B (ring zones), and in each zone B, a plurality of frames are arranged in the radial direction and the circumferential direction. In the circumferential direction, as shown in FIG. 9 , frame 1 to frame n are arranged, and after one circle, there is frame 1 again. In each zone B, the numbers (frame addresses) of a plurality of frames arranged in the radial direction are the same. As address data recorded in the address field 8 shown in FIG. 7, there are frame addresses, tape addresses, and track addresses.

The address data recording method for the address segment 8 adopts a so-called wobble method (Wobble) where a wobble portion 80 is provided on one side wall of the groove G. In addition, in the drawing, the shape of the swing portion 80 is schematically shown. This is the same as in other drawings of FIGS. 1 to 6 described later. In the address data, for example, track addresses such as track N, (N+1), or (N+2) of the groove G, in order to perform correct reading, in one address segment 8 along the circumferential direction of the disc, Two swing portions 80a, 80b are provided. The two oscillating portions 80a, 80b are separately disposed on each of a pair of side walls of the groove G, that is, in a staggered manner. According to the staggered method, even if it is difficult to detect one of the two wobble portions 80a, 80b when the magneto-optical disk is tilted, the other can be detected, so that the reading reliability of address data can be improved.

The push-pull method is used for reading the above address data. Briefly explaining the push-pull method, first, as shown in FIG. 10, the laser light condensed by the objective lens 60 is irradiated on the concave-convex surface where the convex area L and the groove G are formed, and when the light is reflected, positive and negative Negative reflections diffract light R1. As a result, those reflected diffracted lights R1 are also incident on the objective lens 60 in addition to the directly reflected light R0 . The return light is received by a spectroscopic detector 61 having two light-receiving regions 61a, 61b, and a signal SG1 output from the detector 61 corresponding to the light-receiving amounts on the two light-receiving regions 61a, 61b is taken. , SG2 difference. The signal is a push-pull signal, and based on the signal, the swing amount of the laser-irradiated portion in the swing portion can be judged.

The pattern of the above-mentioned magneto-optical disk having the address segment 8 and the data segment 9 is formed as follows: While rotating the disc substrate coated with the photoresist material, the laser beam converged by the objective lens is moved in the radial direction, thereby performing exposure. , and proceed with its development. In the exposure, when one laser beam is divided into two and a portion corresponding to the swing portion 80 is exposed, control is performed so that only one of the two beams is swinged. As described above, one side wall is subjected to wobble processing, and the side wall opposite thereto can form the groove G in a non-wobble state.

However, in the prior art described above, there are problems as described below.

First, in the AS-MO standard magneto-optical disk, the track interval is 0.6 μm. If it is such an interval, it can be properly formed on one side wall of the groove G by using the above-mentioned two laser beams. swing portion 80 . However, in order to further increase the data recording density, for example, when the track pitch is reduced to about 0.3 μm, it is difficult to properly form the wobble portion 80 of the groove G by the above-mentioned method using two laser beams. This is because, if the center-to-center spacing of these beam spots is reduced, their degree of overlap increases so that it is substantially the same as the case of one beam spot.

Second, in the AS-MO optical disc, a red laser with a wavelength of about 650nm is used. On the other hand, in order to further increase the density of magneto-optical disks, it is desirable to use cyan laser light with a wavelength shorter than that of red laser light (for example, a wavelength of about 405 nm) to reduce the size of the beam spot. However, when the cyan laser light is used, the sensitivity of the detector is lowered compared with the case of using the red laser light, and thus there is a problem that the detection of the oscillating portion 80 is incorrect. Especially in the photodetection system of a magneto-optical disk device, since photodetectors are divided into photomagnetic signal detection and servo signal detection, the amount of light used for detection of the wobble portion 80 is reduced, so that the detection error is likely to occur. correct. Furthermore, in order to increase the S/N of the magneto-optical signal, it is necessary to reduce the amount of light used for servo and to increase the amount of light used for detection of the magneto-optical signal, and thus this tendency is further strengthened.

Contents of the invention

It is an object of the present invention to provide an optical disc which eliminates or alleviates the above-mentioned problems.

In the optical disk provided by the present invention, a plurality of grooves and a plurality of lands are arranged alternately in the radial direction of the disk, and an address data recording area is formed on the plurality of grooves by wobbling, and it is characterized in that the address data recording The region has a structure in which a pair of wobbles in phase are formed on both side walls of the groove.

Preferably, the structure of the plurality of grooves is such that a pair of wobble parts with the same phase are formed on each adjacent groove in the radial direction of the disk, and each convex area is provided with a pair of wobble parts formed by the pair of wobble parts. The part that is sandwiched between the parts.

Preferably, as the address data recording area provided in the plurality of grooves, there are a first recording area indicating the respective addresses of the respective grooves and a second recording area indicating the addresses of other grooves adjacent to the respective grooves. recording area, the plurality of grooves has a structure in which a first recording area of one groove and a second recording area of another groove adjacent thereto are opposed with the lands interposed therebetween, and their wobbles are in phase .

Preferably, the first and second recording areas of the plurality of grooves are arranged in an arrangement in which positions are shifted in the circumferential direction of the disc between adjacent grooves in the radial direction of the disc, and the first and second recording areas The portions facing each other with the lands interposed therebetween are configured so as not to be adjacent in the disc radial direction.

Preferably, the plurality of grooves have a structure in which first to third grooves are repeatedly arranged in the radial direction of the disk and have a non-track address area that avoids data recording of the track address, and the first groove has a A structure in which a region representing a track address of the first groove, the above-mentioned non-track address region, and a region representing a track address of a third groove adjacent to the first groove are formed in the following order in the circumferential direction; The second groove has an area indicating the track address of the adjacent first groove, an area indicating the track address of the second groove, and the non-track address formed in the following order in the disk circumferential direction. The structure of the area; the third groove has an area in which the above-mentioned non-track address is formed in the following order in the disk circumferential direction, an area indicating the track address of the adjacent second groove, and an area indicating the third groove. The structure of the field of the track address.

It is preferable that an additional wobble portion indicating data different from the track address is formed in each of the non-track address areas.

It is preferable that the information indicated by the additional wobble portion is information shared by adjacent grooves.

Preferably, the additional wobble portions are respectively provided in adjacent grooves along the radial direction of the disc, and the pair of additional wobble portions are opposed to each other across the land and are in phase.

Preferably, in the first to third grooves, indication data is recorded, the indication data showing which track address is the track address of the groove among the track address data read from the groove. data.

Preferably, the recording of the indication data is realized by a pair of wobbles disposed in phase on both side walls of the respective grooves.

Preferably, the indication data is recorded at the head of one frame area including the first to third grooves.

Preferably, the plurality of grooves and lands includes a plurality of sectors divided by formation areas of a plurality of time marks arranged at constant intervals along the disc circumferential direction on at least the same track.

Preferably, the plurality of sectors includes an address sector and a plurality of data sectors serving as areas used by users, and an address data recording area formed by the wobble is formed in the plurality of address sectors.

Preferably, a portion where the address data recording area is not formed is provided in a portion of the plurality of address segments, and the portion is configured to allow writing of data as a part of an area used by a user.

Other features and advantages of the present invention will be further clarified through the description of the following embodiments of the invention.

Description of drawings

FIG. 1A is a plan view of main parts schematically showing an example of the recording surface pattern of the optical disc of the present invention, and FIG. 1B is a schematic explanatory diagram of an example of a signal obtained when a beam spot is irradiated to the land of the optical disc. ;

2 is a plan view of main parts schematically showing another example of the recording surface pattern of the optical disc of the present invention;

3 is a plan view of main parts schematically showing another example of the recording surface pattern of the optical disc of the present invention;

4 is a plan view of main parts schematically showing another example of the recording surface pattern of the optical disc of the present invention;

5 is a plan view of main parts schematically showing another example of the recording surface pattern of the optical disc of the present invention;

Fig. 6 A is the main part plan view that shows other example of groove and land pattern, and Fig. 6 B is the schematic explanatory diagram of an example of the signal that is obtained by the pattern shown in Fig. 6 A;

FIG. 7 is a plan view of main parts showing an example of the prior art;

The explanatory diagram of the belt of Fig. 8 magneto-optical disc;

Fig. 9 is a schematic diagram of an arrangement of multiple frames;

FIG. 10 is an explanatory diagram of the push-pull method.

Detailed ways

Hereinafter, the best mode for carrying out the present invention will be specifically described with reference to the drawings.

FIG. 1A shows a recording surface pattern of a magneto-optical disk to which the present invention is applicable. The magneto-optical disk D of this embodiment adopts the so-called land/groove recording method, that is, a method in which a plurality of grooves G and lands L arranged in the radial direction (arrow Ra direction) are used as tracks for recording. . Of course, a configuration different from the present embodiment is also possible in which only one of the groove G and the land L is used as a track for recording.

As sectors formed on the track of the groove G, there are first to third address sectors 10A to 10C and a plurality of data sectors 11 with the formation area of the precise time mark 20 interposed therebetween, and on the circumference of the disc. aligned in the direction. The magneto-optical disk D of the present embodiment has a characteristic structure concerning the first to third address fields 10A to 10C, and the other structures are the same as those of conventionally known magneto-optical disks. Therefore, the following description focuses on the structures of the first to third address segments 10A-10C.

In the magneto-optical disk D, so-called address data recording areas formed by double wobble are provided in the first to third address segments 10A to 10C.

More specifically, in the Nth groove G, wobble portions 31a, 31b are formed on both side walls of the first address segment 10A thereof. The wobbling portions 31a and 31b are formed in the same phase in which the wobbling directions are completely coincident, so that the address data indicated by the wobbling portions 31a and 31b are identical to each other. The address data is data modulated in an appropriate way. As the address data, there are frame addresses, tape addresses, and track addresses. The track address indicated by the wobble portions 31a and 31b is N. The track address N is repeatedly recorded twice to one address segment 10A. For the frame address and the tape address, if the track of the same frame and the same tape is common data, it can reduce reading errors. In contrast, for the track address, it is repeated twice in order to avoid false detection. . In this regard, the same applies to other wobbles provided in the first to third address segments 10A to 10C.

Wobble portions 33a', 33b' are formed on both side walls of the third address segment 10C on the Nth groove G. The wobble portions 33a', 33b' are also wobbled in phase with each other, and the track addresses shown by them are the previous address (N-1) of the Nth groove G where they are provided.

As described above, in the N-th groove G, the wobbles 31a, 31b show the original track address of the groove G, and on the other hand, the wobbles 33a', 33b' show the adjacent grooves G's track address. The second address segment 10B of the groove G is an area where no address data is recorded.

In the (N+1)th groove G, wobble portions 31a', 31b', 32a, 32b are formed on both side walls of the first and second address segments 10A, 10B. The wobble portions 31a', 31b' are wobbles in the same phase as the wobble portions 31a, 31b of the above-mentioned N-th groove G, so that the indicated track address thereof is N. The wobble portions 32a, 32b wobble in phase with each other, and the track address shown therein is (N+1). The third address segment 10C of the groove G is an area where no address data is recorded.

In the (N+2)th groove G, wobble portions 32a', 32b', 33a, 33b are formed on both side walls of the second and third address segments 10B, 10C. The wobble portions 32a', 32b' wobble in the same phase as the wobble portions 32a, 32b so that the indicated track address thereof is (N+1). The wobble parts 33a and 33b also wobble in phase with each other, and the track address shown therein is (N+2). The first address segment 10A of the groove G is an area where no address data is recorded.

The structure of the address segment of the groove G after the (N+3)th is basically the same as the address segment of the above-mentioned Nth, (N+1) and (N+2) three grooves G structure repetition. That is, on both side walls of the first address segment 10A of the (N+3)th groove G, wobbles 31c, 31d in phase indicating that the address data is (N+3) are formed, and, in the On the two side walls of the third address segment 10C of the above-mentioned groove G, wobble portions 33 a ′, 33 b ′ having the same phase as the wobble portions 33 a , 33 b of the (N+2)th groove G are formed. Wobbles 31c', 31d in phase with wobbles 31c, 31d indicating that the address data is (N+3) are formed on both side walls of the first address segment 10A of the (N+4)th groove G. ', and, on the two side walls of the second address segment 10B of the groove G, wobbles 32c and 32d indicating that the address data is (N+4) are formed.

Next, the function of the magneto-optical disk D will be described.

First, when a beam spot irradiates the groove G to read address data, two track data can be read. More specifically, for example, with respect to the Nth groove G, the track address N is read from the wobbles 31a, 31b, and the track address (N-1) is simultaneously read from the wobbles 33a', 33b'. For reading the address data of the groove G, the control circuit of the magneto-optical disk device is set in advance so that a track address with a large numerical value is selected as the original track address of the groove G. Thus, for example, for the N-th groove G, the track address of N with a larger numerical value is correctly selected from N and (N-1). The same applies to the grooves G other than the Nth, and these track addresses can be read correctly.

Also, for example, when address data is read by spot-irradiating the first address segment 10A of the N-th groove G with a beam, reflected light from the two wobble portions 31a, 31b can be obtained. Since the two swing portions 31a, 31b swing in phase with each other, the overall swing amount is doubled compared to, for example, a case where only one of the two is formed. Therefore, the wobble detection signal (push-pull signal) detected in the push-pull method described with reference to FIG. 10 has approximately twice the amplitude, thereby improving detection accuracy of wobble, that is, read accuracy of address data. In the magneto-optical disk D, the address segments representing the address data are each provided with two wobbles with the same phase structure, so when reading the address of each groove G, the same result as above can be obtained. effect.

If the detection accuracy of address data can be improved based on the above principle, it is not necessary to increase the amount of light for servo in the photodetection system of the magneto-optical disk device. Therefore, it is possible to increase the amount of light for detecting the magneto-opto signal for data reading from the data segment 11 by a corresponding amount, and also to improve the S/N of the magneto-opto signal. In addition, as described above, if a cyan laser is used instead of a red laser as a laser for reading and writing data, the sensitivity of the photodetector tends to decrease. However, as described above, the magneto-optical disk D of this embodiment can improve The detection sensitivity of address data is also suitable for second-generation optical disk devices using cyan lasers.

When manufacturing the magneto-optical disk D, it is necessary to set two wobbles on the two side walls of an address segment, but since the two wobbles are in the same phase, it can also be formed by using a laser beam . Therefore, the track pitch can be made finer, and the data recording density can be increased.

In the magneto-optical disk D, address data of each land L can also be appropriately read as described below.

If the beam spot Bs shown in FIG. 1A is moved in the direction of the arrow Na along the land L, the swing portions 31b', 32b, and 32a formed on the two grooves G sandwiching the land L are sequentially read. ', 33a. At this time, the wobbles 32b and 32a', which correctly indicate the track address of the land L, are in phase and read simultaneously, so the detection signal has a large amplitude as indicated by symbol Sb in FIG. 1B. On the other hand, the swing portions 31b', 33a exist only on one side of the land L, and no swing portion is formed on the portion facing the land L across the land. Therefore, the detection signal has a half amplitude of the signal shown by symbol Sb, as shown by symbols Sa and Sc in FIG. 1B . Due to the above, when processing the detection signals represented by these symbols Sa~Sc, if the signal detection process is performed using the threshold for cutting off the signals of symbols Sa, Sc, only the signal represented by symbol Sb can be properly extracted , so that the data of the track address of the land L is appropriately read based on this. On the magneto-optical disk D, each of the plurality of lands L is provided with a portion sandwiched by two wobbles of the same phase that correctly represent the address of the land L. Therefore, address reading can be appropriately performed for each land L.

2 to 5 show other examples of the present invention. In these figures, the same symbols as those in the above-mentioned embodiment are used for elements that are the same as or similar to those in the above-mentioned embodiment.

Every two address segments 10A, 10B shown in FIG. 2 correspond to the first and second address segments 10A, 10B on the (N+1)th and (N+2)th grooves G shown in FIG. 1A . Wherein, the first address segment 10A on the (N+2)th groove G shown in FIG. It is different in that swing parts 310a', 310b' and swing parts 311a', 311b' are formed on the two side walls.

The two wobbles 31a', 31b' of the first address segment 10A on the (N+1)th groove G include wobbles 310a, 310b representing preambles, Synchronization (sync), frame address and each data with address. Furthermore, the wobble parts 311a, 311b indicating the preamble and resynchronization (resync) again are included in the wobble parts 31a', 31b'. In the wobble portions 31a', 31b', the portion other than the above is a portion indicating CRC data for track address and data error detection. The wobble parts 310a', 310b' represent the same data as the wobble parts 310a, 310b, and are in the same phase as these wobble parts 310a, 310b. Also, the wobble parts 311a', 311b' represent the same data as the wobble parts 311a, 311b, and are in the same phase as these wobble parts 311a, 311b.

According to the above structure, since data such as a preamble signal is also added to the first address segment 10A (10A') on the (N+2)th groove G, compared with the case of the embodiment shown in FIG. 1A, the frame The starting position of is more explicit. As described above, in the present invention, data other than the track address or CRC can be recorded in the address segment where it is not necessary to record the track address. In the structure shown in FIG. 1A, there are second and third address fields 10B and 10C without wobbles. Of course, wobbles representing common data other than track addresses and CRCs may be provided for these address fields.

In the structure shown in FIG. 3, as the address field of the groove G, only the first and second address fields 10A, 10B are provided. In this structure, no segment corresponding to the third address segment 10C of the embodiment shown in FIG. 1A is provided. The first address segment 10A is divided into an area s1 on the left and an area s2 on the right in the same figure, and an address including N, (N+1), The wobble part 30 of the address data of the track address such as (N+2) or (N+3). On the other hand, in the second address field 10B, only the area s3 on the left in the figure is used as an area representing address data, and the wobble portion 30 is appropriately provided. In addition, the same track address is not repeated twice in any of the wobble parts 30, but only once, and the structure is also different from the embodiment shown in FIG. 1A in this point.

When irradiating laser light to a magneto-optical disk to read data, there are two methods, that is, by irradiating laser light on a transparent substrate of a magneto-optical disk so that the light transmitted through the transparent substrate reaches the recording surface, and from a transparent A method in which the thin transparent protective film on the opposite side of the substrate is irradiated with laser light to the recording surface. According to the so-called double swing method of the present invention, compared with the so-called single swing method of the prior art, it is difficult to be affected by the tilt, but if the latter method is adopted, it is more difficult to be affected by the tilt of the magneto-optical disk during data reading. . Therefore, even if the track address is not repeatedly stored twice, the track address can be properly read. The structure shown in FIG. 3 is the best when the above method is adopted.

In the embodiment shown in FIG. 3, the address data area can be reduced by not repeating the same track address twice on the same track, and only using the first and second address segments 10A, 10B as address segments so that the total number is reduced. . Therefore, it is possible to expand the data area for users. In particular, the right area s4 of the second address segment 10B can be used as a magnetically recorded data area similarly to the data segment 11 . Therefore, it is advantageous to improve format efficiency and increase data storage capacity.

In FIG. 3, for example, the right region s2 of the first address field 10A indicated by symbol n1 and the left region s3 of the second address field 10B indicated by symbol n2 are structures in which no wobble is formed. In the present invention, as described with reference to FIG. 2 , a wobble portion representing a preamble signal or other data may be formed on the above-mentioned portion. More specifically, for example, as shown in FIG. 4 , wobble portions 300a', 300b' are formed on address fields 10A, 10B indicated by symbols n1', n2' as portions corresponding to the above address fields. The wobble portion 300a' is synchronized with the wobble portion 300a representing the re-preamble signal and resynchronized data included in the wobble portion 30 of the adjacent address segment 10A indicated by symbol n3. In addition, the wobble 300b' is synchronized with the wobble 300b representing the preamble, synchronization, frame address, and data with address included in the wobble 30 of the adjacent address segment 10B indicated with symbol n4. Also in this configuration, as in the case shown in FIG. 2 , it is easy to recognize the head of the frame when reading data.

In the structure shown in FIG. 5, the wobble portion 30 is formed by constant arrangement in the right region s6 of the first address segment 10A and the left and left regions s7, s8 of the second address segment 10B. Regarding these oscillating portions 30 , the point that the opposing oscillating portions have the same phase relationship is the same as in the previous embodiment. A pattern seen in plan as shown in FIG. 6A is formed on the left region s5 (head region) of the first address segment 10A. According to the pattern shown in the figure, the passing beam spot passes through the Nth, (N+1) and (N+2)th respective convex areas L(N), L(N+1), L(N+2) ) The obtained push-pull signal is the waveform as described in (a)-(c) of FIG. 6B. This is because, among the portions shown in FIG. 6A , the amplitude of the push-pull signal is larger in the portion that oscillates in the same phase than in other portions. Here, if in the push-pull signal shown in Fig. 6B(a)~(c), the part with large amplitude is set to "1" and the part with small amplitude is set to "0", then in the land L(N) A (1,0) signal can be obtained, a (0,1) signal can be obtained in the convex area L(N+1), and a (0,0) signal can be obtained in the convex area L(N+2). Based on these signals, three types of lands L(N), L(N+1), L(N+2) can be distinguished. Therefore, based on the data, it can be judged which of the track addresses read on the land L is to be employed.

Specifically, in the structure shown in FIG. 5, when the beam spot is made to pass through the portion of the land L(N), the three track addresses of N, (N+1) and (N-1) are Read in the above sequence, but when the signal is detected, it is predetermined to use the first track address to be read. As mentioned above, the second and third read (N+1), (N-1) have wrong addresses and are not used. Also, based on the above-mentioned signal, it is possible to cause the address to be read second with respect to the land L(N+1), and the address to be read third with respect to the land L(N+2). As described above, on the portion where the wobble portion is provided only on one side of the land L, since the amplitude of the push-pull signal becomes small, it can be prevented from being detected as an appropriate track address by mistake. The above method can further reliably prevent the problem of wrongly detecting the track address.

The present invention is not limited to the contents of the above-mentioned embodiments. The specific structure of each part of the optical disc in the present invention can be freely changed in various designs.

In the present invention, the specific number of address fields provided on one track or frame is not limited to two or three. For example, only one address field may be provided, and wobbles representing N, (N+1) or (N+2) types of track addresses may be formed on this one address field so that they are arranged in the circumferential direction of the disc.

The optical disk of the present invention is not limited to a magneto-optical disk as understood in the opening definition. The present invention is applicable to various optical discs as long as wobble is used for address data recording.

Claims (12)

1. An optical disc, on the radial direction of the disc, a plurality of grooves and a plurality of lands are intersected in the manner of forming different tracks, and an address data recording area is formed by wobbling on the plurality of grooves, It is characterized in that, The structure of the address data recording area is: at the same position in the disc circumferential direction, a pair of wobble parts with the same phase are formed on the two side walls of the groove, As the address data recording areas provided on the plurality of grooves included in each track, there are first recording areas indicating the original addresses of the respective tracks and addresses indicating other tracks adjacent to the respective tracks. second area, A groove in which the first recording area is formed in one track and another groove in which the second recording area is formed in an adjacent track are opposed to each other across the land, and Their swing parts are in phase. 2. The optical disc according to claim 1, wherein the arrangement of the first and second recording areas in the one track, the arrangement of the first and second recording areas in other tracks adjacent to the radial direction of the disc, The arrangement of the regions is staggered in the circumferential direction of the disk, Furthermore, the positions of the lands sandwiched between the first and second recording regions having the same phase are shifted in the disk circumferential direction for each track. 3. The optical disc as claimed in claim 2, wherein the structure of the plurality of grooves is: repeatedly arranged in the disc radial direction, and has a non-track address area that avoids the recording of data of the track address, The structure of the groove included in the Nth track is that an area indicating the track address of the track, the non-track address area, and an area indicating the track address related to the Nth track are formed in the following order in the disk circumferential direction. The area of the adjacent N-1 track address; The structure of the groove included in the N+1-th track is that an area indicating the track address of the N-th track, an area indicating the N+1-th track are formed in the following order in the disk circumferential direction. the track address area, and the non-track address area; The structure of the groove included in the N+2th track is that the non-track address region, the region representing the track address of the N+1th track, and the An area indicating the track address of the N+2th track. 4. The optical disc according to claim 3, wherein an additional wobble representing data different from the track address is formed in each of the non-track address areas. 5. The optical disc according to claim 4, wherein the information indicated by the added wobble is common to grooves adjacent to each other at the same position in the disc circumferential direction. 6. The optical disc according to claim 5, wherein the additional wobble part is opposite to the wobble part of the adjacent groove in the radial direction of the disc with the land sandwiched between them, and is in phase. 7. The optical disc according to claim 3 , wherein indication data is recorded in each of the tracks, and the indication data shows which track address is the track address among the track address data read from the track. The data of the track address of the track. 8. The optical disc according to claim 7, wherein the recording of said index data is formed by a pair of wobbles arranged in phase on both side walls of said respective grooves. 9. The optical disc according to claim 8, wherein the indication data is recorded at the head of one frame area in each track. 10. The optical disc according to claim 1, wherein the plurality of grooves and lands comprise a plurality of segments formed by a plurality of segments arranged at constant intervals along the disc circumferential direction on at least the same track. The formation area of multiple time stamps is divided. 11. The optical disc according to claim 10, wherein, as the plurality of sectors, there are an address sector and a plurality of data sectors serving as areas used by users, and the plurality of address sectors are formed with the wobble. Address data recording area. 12. The optical disc as claimed in claim 11, wherein, a part where the address data recording area is not formed is provided on a part of the plurality of address segments, and the structure of the place can be performed as a part of the user use area. Data writing.

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