JP2002133665A - Method for detecting address of optical disc, optical disc device, optical disc, and method for making optical disc original - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for detecting optical disc address that can detect address information even if a wobble mark exists overlapping radially. SOLUTION: Figure 3 shows the block diagram of an address signal processing part in an optical disc device. The address signal processing part is composed of a wobble signal/a wobble mark signal separating circuit, a wobble mark detecting circuit, and a L/G identifying circuit. The wobble signal/ the wobble mark signal separating circuit inputting PP1 and PP2 separates the wobble signal controlling the number of revolutions of the disc from the wobble mark signal of the address information. The wobble mark signal outputted from the separating circuit is detected by threshold levels th1 and th2 in the wobble mark detecting circuit, inputs the detecting signal to the L/G identifying circuit, identifies from which of PP1 and PP2 the wobble mark has been outputted and outputs the L/G identifying signal and the address information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk, an optical disk apparatus, an optical disk address detection method, and a method for manufacturing an optical disk master.

[0002]

2. Description of the Related Art In recent years, recordable optical disks (for example, CD-Rs and MDs), which have spread rapidly, record address information by wobbling grooves. In this method, grooves are wobbled in the radial direction, and address information is given by modulating the wobble frequency in a certain method. If the wobble frequency is set to a frequency higher than the trackable frequency of the optical disk recording / reproducing device, the light spot does not follow the wobble frequency, so that a wobble frequency component is superimposed on the tracking error signal, and the address is detected by detecting the wobble signal. Information is obtained. The density of this optical disc has been remarkably increased in recent years, and there is an L / G (land / groove) recording method as a method for expanding the recording capacity. In this method, data recorded in only one of the groove and the land is recorded in both the groove and the land. However, in the above-described method of wobbling the groove, there is a problem in that the address information of the land track cannot be obtained because the address information of two adjacent groove tracks is superimposed on the wobble signal of the land track. . By the way, in the invention described in Japanese Patent Application Laid-Open No. 9-44907, address information is formed on an optical disk substrate as a wobble mark that can be shared by a land track and a groove track.
The demodulation is performed by changing the RF signal or the TE signal.

[0003]

The prior art is called CLV (Co
It is applied to an optical disk of the nstant Liner Velocity (constant linear velocity) method, and the address information is push-pull signal (hereinafter P)
When the detection is performed using the P signal, there is a problem as described below. FIG. 7A is an enlarged view of the optical disk substrate, and FIG. 7B shows a PP signal obtained when the reproduction light spot moves along the line AB in the figure. FIG.
When tracking the L Tr1 (land track) in (1), a PP signal is generated at a position where a wobble mark exists because the groove cross-sectional shape in the radial direction is asymmetric, and the PP signal shown in FIG. can get. By using this signal, address information can be detected. However, when the wobble marks of the adjacent tracks overlap in the radial direction, L
When tracking Tr2, the groove cross-sectional shape in the radial direction is symmetric even at the position where the wobble mark exists.
No PP signal is generated. Therefore, if the wobble marks overlap in the radial direction, the address information cannot be detected. The same applies to groove tracks.

Accordingly, a first object of the present invention is to provide an optical disk address detecting method capable of detecting address information even when wobble marks are overlapped in the radial direction. A second object of the present invention is to provide an optical disk device capable of detecting address information even when wobble marks are overlapped in the radial direction. A third object of the present invention is to provide an optical disc capable of accurately controlling the number of revolutions of the disc without impairing the recording capacity. A fourth object of the present invention is to provide an optical disk capable of improving the reproduction signal characteristics.

A fifth object of the present invention is to provide a method for detecting an address of an optical disk which can identify each track even when one track is shared by four tracks. A sixth object of the present invention is to provide an optical disk device that can identify each track even if one track is shared by four tracks. A seventh object of the present invention is to provide an optical disk capable of improving the reproduction signal characteristics and a method for producing a master disk of an optical disk capable of accurately controlling the rotation speed of the disk without impairing the recording capacity. .

[0006]

According to the present invention, lands and grooves having substantially the same track width are formed on a substrate, and address information is recorded by wobbling the grooves by the track width in the radial direction. First detecting means for detecting the first reflected light applied to one of the track boundaries on the L / G recording optical disc, and second reflected light applied to the other track boundary. Detecting means for detecting the third reflected light irradiated on the center of the track, based on the third reflected light detected by the third detecting means. When recording and reproducing information while performing tracking control, the land address information is grouped by a push-pull signal obtained from the first reflected light detected by the first detection means. The first object is achieved by detecting the address information of the bus with a push-pull signal obtained from the second reflected light detected by the second detecting means.

According to the second aspect of the present invention, lands and grooves having substantially the same track width are formed on the substrate, and address information is recorded by wobbling the grooves by the track width in the radial direction. An optical disc apparatus for reproducing address information of a recording type optical disc, comprising: a first detecting means for detecting a first reflected light irradiated on one track boundary; and a second detecting means for irradiating the other track boundary. Second detecting means for detecting the reflected light, third detecting means for detecting the third reflected light applied to the center of the track, and control for performing tracking control based on the reflected light detected by the third detecting means With means,
Comparing a push-pull signal obtained from the first reflected light detected by the first detecting means with a push-pull signal obtained from the second reflected light detected from the second detecting means, The second object is achieved by further including an identification means for identifying whether the third reflected light is a land or a groove reflected light.

According to the third aspect of the invention, lands and grooves having substantially the same track width are formed on the substrate, and the address information is recorded by wobbling the grooves by the track width in the radial direction. In the optical disc of the recording system, only the odd-numbered or even-numbered grooves wobble at a constant frequency, and the frequency is lower than the wobble frequency of the address information, thereby achieving the third object.

According to the fourth aspect of the invention, lands and grooves having substantially the same track width are formed on the substrate, and address information is recorded by wobbling the grooves by the track width in the radial direction. The fourth object is achieved by recording address information on every other track of a recording optical disk and sharing address information between adjacent lands and non-wobbled grooves. According to a fifth aspect of the present invention, in the fourth aspect, only the groove in which the address information is recorded wobbles at a constant frequency, and the frequency is lower than the wobble frequency of the address information. .

According to a sixth aspect of the present invention, there is provided the optical disk address information detecting method according to the fourth or fifth aspect, wherein the first reflected light applied to one track boundary is detected, and the other track is detected. When reproducing the land or groove address information while performing tracking control based on the third reflected light by detecting the second reflected light irradiated on the boundary, detecting the third reflected light irradiated on the track center, The fifth object is achieved by detecting a change in the push-pull signal obtained from the first, second, and third reflected lights to identify the land and the groove. According to a seventh aspect of the present invention, there is provided an optical disc apparatus for recording / reproducing the optical disc according to the fourth or fifth aspect, wherein the first reflected light detected on the one track boundary is detected.
Detecting means, a second detecting means for detecting the second reflected light applied to the other track boundary, and a third detecting means for detecting the third reflected light applied to the track center,
When reproducing the land or groove address information while performing tracking control based on the third reflected light detected by the third detecting means, the first detecting means and the second
And a signal processing means for detecting a change in the push-pull signal obtained from the reflected light detected by the detecting means and the third detecting means and discriminating the land and the groove from the detected change in the push-pull signal. The sixth object is achieved.

According to an eighth aspect of the present invention, there is provided the optical disk master forming method for an optical disk according to the third, fourth or fifth aspect, wherein the signal generated every rotation of the turntable on which the optical disk master is mounted is provided. To determine whether or not to wobble the exposure laser light based on the detection,
The seventh object is achieved by determining whether or not to output a wobble signal every other track.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. (Reproduction method, optical disk device) L / G shown in FIG.
The optical disk of the recording method includes a groove Gn and a land Ln (n:
1, 2, 3, ...) share the address information. Recording and reproduction of information are performed by a three-beam method, and the positions of the beam spots are arranged as shown in FIG. The land and groove address information are respectively stored in the sub beam 1
(SB1) and the PP signals PP1 and PP2 obtained from the sub beam 2 (SB2) are used. When the MB tracks the land, as shown in FIG. 1 (2), when there is a wobble mark, PP1 (the PP signal of SB1) drops, but when there is no wobble mark, it is constant. Therefore, if the threshold value th1 is provided for PP1,
A wobble mark signal can be detected. On the other hand, the groove uses PP2 (PP signal of SB2). When tracking the groove, as shown in FIG. 1 (3), when there is a wobble mark, PP2 drops, while when there is no wobble mark, it is constant. Therefore, if a threshold value th2 is provided for PP2, a wobble mark signal can be detected in the same manner as for a land.

Further, even when a wobble mark is formed in an adjacent groove such as a land Ln + 2,
Since SB1 is arranged at the boundary between the groove and the land, the signal amplitude of PP1 changes due to the wobble mark. Similarly, in the case of the groove Gn + 3, the signal amplitude of the PP2 changes due to the wobble mark.

FIG. 3 is a block diagram of an address signal processing section of the optical disk device according to the present embodiment. The address signal processing unit includes a wobble signal / wobble mark signal separation circuit, a wobble mark detection circuit, and an L / G identification circuit. The wobble signal / wobble mark signal separation circuit for inputting PP1 and PP2 separates a wobble signal for controlling the disk rotation speed and a wobble mark signal as address information. The wobble mark signal output from the separation circuit is detected by a wobble mark detection circuit based on threshold levels th1 and th2,
This detection signal is input to the L / G identification circuit to identify which of the PP1 and PP2 the wobble mark has been output from, and outputs an L / G identification signal and address information.

(Optical Disk) In order to accurately record information on an optical disk, it is necessary to accurately control the number of rotations of the disk. To control it with a wobble mark,
A synchronization mark is required in addition to the address information mark, and the area for recording and reproducing information is reduced accordingly, that is, the recording capacity of the disk is reduced. Therefore, in the optical disc of the present embodiment, as shown in FIG. 2, the grooves are wobbled at a constant frequency every other track.
Thus, even in the land, the disk rotation speed can be controlled by the wobble signal of the predetermined groove without being affected by the wobble of the adjacent groove. The wobble signal is detected at PP1 in the land and at PP2 in the groove. A wobble signal is superimposed on PP1 and PP2 in addition to the wobble mark. Since the wobble frequency is set higher than the trackable frequency and lower than the wobble mark frequency, the wobble signal and the wobble mark signal are separated. be able to. Therefore, the disk rotation speed can be controlled so that the wobble signal has a predetermined frequency.

Next, a second embodiment will be described. (Optical Disk) FIG. 4A is an enlarged view of a disk substrate according to the present embodiment. Track [L1, G1,
[L2, G2], the four tracks share an address. Therefore, the wobble marks are formed every other track of the groove, so that the wobble marks of the adjacent tracks are not formed overlapping. In addition, there is an advantage that the influence of crosstalk due to the wobble mark can be reduced in a reproduced signal after data recording. Further, if only the groove forming the wobble mark is wobbled at a constant frequency, no unnecessary wobble mark is formed as in the first embodiment, so that the number of rotations of the disk is controlled without impairing the recording capacity. be able to.

(Reproduction method, optical disk apparatus) FIG. 4 (4)
As shown in the figure, when the MB tracks G2 or L1, the wobble mark causes the PPO to be on the + side. When the MB tracks G1 or L2, the PPO
Then, a PP signal is generated on the negative side. Here, when PPO occurs on the + side, it is necessary to identify which of G2 and L1 is being tracked. This is possible by monitoring the PP signal PP3 obtained from BS3.

If the MB is tracking L1,
The PP signal shown by the solid line in FIG. 4 (2) is generated by the wobble mark, whereas the PP signal shown by the dotted line in G2.
A P signal is generated. Therefore, G2 and L1 can be identified by setting the threshold value th3 and detecting whether or not this is detected.
Similarly, when PPO occurs on the negative side, G1 and L2 can be identified by monitoring PP4 obtained from BS4 and setting a threshold th4.

FIG. 5 is a block diagram of an address signal processing section of the optical disk device according to the present embodiment. The basic configuration is the same as that of FIG. 3, but a similar separation circuit and wobble mark detection circuit are added to the PPO in order to identify lands and grooves. In the wobble detection circuit of the PPO, the wobble mark signal is set to a threshold value t.
The signal indicating which of h5 and th6 has been detected is L / G
Input to the identification circuit. Further, in the wobble detection circuits of PP3 and PP4, a signal indicating whether the wobble mark signal is detected at the threshold value th3 or th4 is set to L /
By inputting to the G identification circuit, the address information becomes G
1, G2, L1, or L2.

(Method of Manufacturing Optical Disk Master) The method of manufacturing the optical disk master according to the present embodiment will be described with reference to FIG. FIG. 6 is a configuration diagram of an optical disk master exposure machine. The laser beam emitted from the laser tube passes through an optical modulator and an optical deflector, and its beam diameter is expanded by a beam expander (not shown).
= 0.9) and is focused on the master optical disc. The optical modulator sets the laser light intensity on the light-converging surface and turns on / off the laser light in accordance with a signal from a formatter via an exposure machine control device. The optical deflector deflects a laser beam according to a signal from a formatter via an exposure machine control device. The formatter outputs a wobble signal and a wobble mark signal. The exposure machine control device controls the rotation speed of the turntable, focus control of the optical head, and the like, in addition to the control of the optical modulator and the optical deflector.

The glass master was prepared by applying a photoresist on a polished and washed glass substrate by a spin coating method and then baking it in a clean oven. By moving the glass master or the optical head by a fixed distance TP for each rotation while rotating the glass master using the optical disk master exposure apparatus described above, the glass master is grooved with a track pitch TP on the glass master. Is formed. By developing this, a groove is formed on the glass master. In order to form a wobble mark every other groove track, a signal generated every time the turntable makes one rotation is detected by a formatter, and a wobble mark signal is output only for an odd track. In the same manner, grooves wobbled every other track were formed.

[0022]

According to the first aspect of the present invention, in the optical disk reproducing method, the address information is detected by the change of the PP signal of the sub-beam irradiated on the track boundary, so that even if the wobble mark exists in the adjacent track, the address is detected. Information can be demodulated. In the invention according to claim 2,
Since the optical disk device is provided with a signal processing means for determining which of the two sub beams has detected the wobble mark, it is possible to identify whether the track being reproduced is a land or a groove.

According to the third aspect of the present invention, in the optical disk, the grooves are wobbled at a constant frequency separately from the wobble mark, so that the disk rotation speed can be accurately controlled without impairing the recording capacity. According to the fourth aspect of the present invention, in the optical disc, since the address information is shared by four tracks, the influence of the crosstalk of the wobble mark can be reduced, so that a good reproduction signal can be obtained.

According to the fifth aspect of the present invention, in the optical disk, the groove is wobbled at a constant frequency separately from the wobble mark, so that the disk rotation speed can be accurately controlled without impairing the recording capacity. According to the sixth aspect of the present invention, in the optical disk reproducing method, changes in the PP signal of the main beam and the sub beam are detected, and whether they are lands or grooves is identified based on the relationship, so that one address information is recorded in four tracks. Can be shared.

According to the seventh aspect of the present invention, the optical disk apparatus is provided with signal processing means for monitoring a wobble mark detection signal at each spot of three beams and judging a relation between them, so that four tracks are provided. At 1
Each track can be identified by sharing one piece of address information. According to the eighth aspect of the present invention, in the method of manufacturing the master optical disc, a signal generated every rotation of the turntable is detected to determine whether or not the exposure laser light is wobbled. Grooves can be formed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an optical disk of the L / G recording system.

FIG. 2 is a diagram showing that the groove is wobbled every other track at a constant frequency in the optical disc of the present embodiment.

FIG. 3 is a block diagram of an address signal processing unit of the optical disc device according to the present embodiment.

FIG. 4 is an enlarged view of a disk substrate according to the embodiment.

FIG. 5 is a block diagram of an address signal processing unit of the optical disc device according to the present embodiment.

FIG. 6 is a diagram showing a configuration of an optical disk master exposure machine.

FIG. 7 is an enlarged view of a conventional optical disk substrate.

Claims (8)

[Claims] 1. An L / G recording type optical disk in which lands and grooves having substantially equal track widths are formed on a substrate, and address information is recorded by wobbling the grooves by a track width in a radial direction. First detecting means for detecting the first reflected light applied to one track boundary, second detecting means for detecting the second reflected light applied to the other track boundary, and track center And a third detecting means for detecting a third reflected light applied to the recording medium. When recording and reproducing information while performing tracking control based on the third reflected light detected by the third detecting means, The push-pull signal obtained from the first reflected light which detects the land address information by the first detecting means converts the groove address information into the second detecting means. Optical disk address detection method characterized by detecting by the second push-pull signal obtained from the reflected light of which is detected more. 2. An address of an L / G recording type optical disk in which lands and grooves having substantially equal track widths are formed on a substrate, and address information is recorded by wobbling the grooves by a track width in a radial direction. An optical disc device for reproducing information, comprising: a first detecting means for detecting a first reflected light applied to one track boundary; and a second detecting means for detecting a second reflected light applied to the other track boundary. A second detecting means, a third detecting means for detecting a third reflected light irradiated to the center of the track, and a control means for performing tracking control based on the reflected light detected by the third detecting means. A push-pull signal obtained from the first reflected light detected by the first detecting means, and a push-pull signal obtained from the second reflected light detected by the second detecting means. An optical disc device further comprising an identification unit that compares the signal with a double signal to identify whether the third reflected light is land or groove reflected light. 3. An L / G recording type optical disk in which lands and grooves having substantially equal track widths are formed on a substrate and address information is recorded by wobbling the grooves by a track width in a radial direction. An optical disc characterized in that only odd-numbered or even-numbered grooves wobble at a constant frequency, and that frequency is lower than the wobble frequency of address information. 4. An L / G recording type optical disk in which lands and grooves having substantially equal track widths are formed on a substrate and address information is recorded by wobbling the grooves by a track width in a radial direction. An optical disk characterized in that address information is recorded on every other track of a groove, and the address information is shared between adjacent lands and non-wobbled grooves. 5. The optical disk according to claim 4, wherein only the groove in which the address information is recorded wobbles at a constant frequency, and the frequency is lower than the wobble frequency of the address information. 6. The method for detecting address information of an optical disk according to claim 4, wherein the first reflected light applied to one track boundary is detected, and the first reflected light applied to the other track boundary is detected. 2 reflected light is detected, and the third reflected light irradiated to the track center is detected,
When reproducing land or groove address information while performing tracking control based on the third reflected light, a change in the push-pull signal obtained from the first, second, and third reflected lights is detected, and the land and the groove are detected. A method for detecting address information of an optical disc, characterized by identifying 7. An optical disk apparatus for recording / reproducing an optical disk according to claim 4 or 5, wherein a first detecting means for detecting a first reflected light applied to one track boundary, and a second detecting means for detecting the first reflected light. A second detecting means for detecting a second reflected light applied to the track boundary, and a third detecting means for detecting a third reflected light applied to the center of the track; When reproducing the land or groove address information while performing tracking control based on the third reflected light, the first detecting means and the second
And a signal processing means for detecting a change in the push-pull signal obtained from the reflected light detected by the detecting means and the third detecting means, and identifying a land and a groove from the detected change in the push-pull signal. Characteristic optical disk device. 8. A method for preparing an optical disk master for an optical disk according to claim 3, 4 or 5, wherein a signal generated every rotation of a turntable on which the optical disk master is mounted is detected, and the detection is performed. Determining whether or not to wobble the exposure laser beam based on the above, and determining whether or not to output a wobble signal every other track.