JPH1064124A - Apparatus for producing master disk for optical disk, production of master disk for optical disk, device for forming optical disk, method for forming optical disk, and optical disk reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the sure reproducing of addresses both at the time of reproduction of grooves and at the time of reproduction of lands by forming the grooves of a prescribed width on a master disk and forming header parts by prescribed pits. SOLUTION: A stamper is formed by using a glass master disk and an optical disk (RAM) 51 on which data are to be recorded in the grooves and the lands for recording and reproducing, is formed by using the stamper. The head parts of each recording area of the RAM 51 are composed of the plural pits and are preformatted for the grooves. The edges in the tangent direction of the disk on one side exist on the same line as the one side edge of the grooves and the edge on the other one side exist in the positions of the center lines of the lands in the form protruding to the lands. The pits of the head parts are asymmetrical with the center lines of the grooves. The output signals of adders 26c, 26d are supplied to a land/groove discrimination circuit 40. The circuit 40 discriminates whether the reproducing beam corresponds to the lands or grooves or not by the respective added outputs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for recording data or reproducing recorded data using both concentric or spiral grooves and lands, and using recording marks at predetermined intervals in a mastering step. The present invention relates to an optical disc master manufacturing apparatus, an optical disc master manufacturing method, an optical disc creating apparatus, an optical disc creating method, and an optical disc reproducing apparatus used when creating a rewritable optical disc in which address data is recorded.

[0002]

2. Description of the Related Art In recent years, data has been recorded in both guide grooves (grooves) and flat portions (lands) between the guide grooves.
Alternatively, an optical disk for reproducing recorded data has been proposed (see Japanese Patent Publication No. 63-57895).

In such an optical disk, an address signal is preformatted in each of a groove and a land. This preformat is performed at the same position in the tangential direction.

At this time, especially when the track pitch is narrow in a high-density optical disk, when an address signal is present at the same position in the tangential direction of the groove and the land, if the address signal is pre-formatted to both the land and the groove, However, there is a problem in that the edges of the contacts come into contact with each other, so that address pits are not formed and the address cannot be reproduced.

[0005]

As described above, data recording or reproduction of recorded data is performed using both the groove and the land, and address data is recorded at predetermined intervals by a recording mark in a mastering step. In a rewritable optical disc to be recorded, the disadvantage that address reproduction cannot be performed at the time of groove reproduction or land reproduction is eliminated, and address reproduction is reliably performed at both groove reproduction and land reproduction. It is an object of the present invention to provide an optical disc master manufacturing apparatus, an optical disc master manufacturing method, an optical disc creating apparatus, an optical disc creating method, and an optical disc reproducing apparatus capable of performing the following.

[0006]

According to the optical disk master manufacturing apparatus of the present invention, data is recorded or recorded data is reproduced by using both concentric or spiral grooves and lands. In the manufacture of a master for use in producing a rewritable optical disk having a header portion composed of address data at intervals, a groove having a predetermined width is formed on the master and a piece is formed asymmetrically with respect to the center line of the groove. The pits are formed by means for forming a header portion.

An optical disk master manufacturing apparatus according to the present invention comprises:
Data is recorded or reproduced using both concentric or spiral grooves and lands, and a rewritable optical disk having a header portion composed of address data at predetermined intervals is prepared in advance. In the production of masters used for
A groove having a predetermined width is formed on the master, and one edge of the pit constituting the header portion in the tangential direction of the disk is on the same tangential direction as one edge of the groove, and the other edge of the pit in the tangential direction of the disk is , Which are formed substantially tangentially to the center axis of the land.

An optical disk producing apparatus according to the present invention is used to produce a rewritable optical disk in which data is recorded or recorded data is reproduced using both concentric or spiral grooves and lands. While forming a groove of a predetermined width on the master,
Manufacturing means for producing pre-pit data consisting of address data by means of pits formed asymmetrically with respect to the center line of the groove at predetermined intervals to produce a master for a rewritable optical disc; A first creator for creating a rewritable optical disk stamper using the original master, and a second creator for creating a rewritable optical disk using the stamper created by the first creator. Is done.

An optical disk producing apparatus according to the present invention is used for producing a rewritable optical disk in which data is recorded or recorded data is reproduced by using both concentric or spiral grooves and lands. While forming a groove of a predetermined width on the master,
One edge of the pits constituting the header portion at predetermined intervals in the disk tangential direction is on the same tangential direction as one edge of the groove, and the other edge of the pits in the disk tangential direction is substantially tangent to the land center axis. Manufacturing means for manufacturing a master for a rewritable optical disc by forming the master on the direction, first creating means for creating a stamper for a rewritable optical disc using the master manufactured by the manufacturing means, and And a second creating means for creating a rewritable optical disk using the stamper created by the creating means.

In the optical disk reproducing apparatus of the present invention, a concentric or spiral groove having a predetermined width is formed, and a header portion is formed by pits which are asymmetrically formed with respect to the center line of the groove. In reproducing a rewritable optical disc in which data is recorded or recorded data is reproduced using both of the lands, an irradiating means for irradiating the optical disc with a laser beam; The reflected light is guided by the detecting means having two regions separated by a dividing line parallel to the tangential direction of the optical disc, and the detected light amount guided to the two regions detected by the detecting means is compared with each other. Judgment to determine whether the position irradiated with the laser beam by the irradiation means is a groove or a land Consisting of stage.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a cutting apparatus for producing a master glass (mastering step) when producing a stamper. In FIG. 1, the cutting device melts the photoresist by turning on and off the laser power while the photoresist is applied on the glass substrate 1 when a glass master for a recording / reproducing optical disk (RAM) is formed. By doing so, a groove (recess) is formed, and a header portion is formed by a minute concave recording mark (pit).

In FIG. 1, a glass substrate 1 coated with a photoresist is rotated by a motor 3 at a constant speed, for example. The motor 3 is controlled by a motor control circuit 4.

The cutting process on the glass substrate 1 is performed by the optical head 5. The optical head 5 is fixed to a drive coil 7 that constitutes a movable portion of a linear motor 6, and the drive coil 7 is connected to a linear motor control circuit 8
It is connected to the.

A speed detector 9 is connected to the linear motor control circuit 8, and a speed signal from the speed detector 9 is sent to the linear motor control circuit 8. Further, a permanent magnet (not shown) is provided at a fixed portion of the linear motor 6, and when the drive coil 7 is excited by the linear motor control circuit 8, the optical head 5
The glass substrate 1 is moved in the radial direction.

The optical head 5 holds an objective lens 10 by a wire or a leaf spring (not shown).
The objective lens 10 is moved in the focusing direction (the optical axis direction of the lens) by the drive coil 12 and is movable in the tracking direction (the direction orthogonal to the optical axis of the lens) by the drive coil 11.

The laser beam generated by the laser generator 19 driven by the laser control circuit 13 is transmitted through the half prism 21 and the objective lens 10 to the glass substrate 1.
The light reflected upward from the glass substrate 1 is guided to a photodetector 24 via an objective lens 10, a half prism 21, a condenser lens 22, and a cylindrical lens 23.

As shown in FIG. 2, the laser generator 19
A semiconductor laser oscillator (or an argon-neon laser oscillator) 19a for generating laser light, a collimator lens 19b for collimating the laser light from the semiconductor laser oscillator 19a, and a laser light from the collimator lens 19b for transmitted light and reflected light. Beam splitter 1
9c, a modulator 19d that modulates the laser light transmitted through the beam splitter 19c, a modulator 19f that modulates the laser light reflected by the beam splitter 19c and guided through the mirror 19e, and transmits the laser light from the modulator 19d. In addition, it is constituted by a half prism 19h that reflects a laser beam guided from the modulator 19f via a mirror 19g.

Each of the modulators 19d and 19f selectively shields a guided laser beam according to a control signal from the laser control circuit 13, and is composed of, for example, a shutter or the like. The modulator 19d modulates according to the modulation signal shown in FIG. 3C, thereby transmitting laser light at the time of generating a groove and at the time of generating an address pit. By modulating according to the modulation signal shown in FIG. 3B, the laser light is transmitted when the address pit is generated.

The laser beam Ca from the modulator 19d is guided to the glass substrate 1 via the half prism 19h, the half prism 21 and the objective lens 10, and the laser beam Cb from the modulator 19f is sent to the mirror 19g and the half prism 1
9h, it is guided to the glass substrate 1 via the half prism 21 and the objective lens 10.

At this time, the mirror 19g is adjusted so that the center of the laser beam Ca coincides with the center of the groove, and the center of the laser beam Cb is shifted from the center of the groove in the radial direction of the glass substrate 1. Have been.

As a result, as shown in FIG.
The center of the laser light Ca matches the center of the groove, and the upper end of the laser light Cb matches the center of the land. The photodetector 24 includes four divided photodetection cells 24a, 24b, and 24.
c, 24d.

The output signal of the photodetector cell 24a of the photodetector 24 is supplied to one end of adders 26a and 26d via an amplifier 25a, and the output signal of the photodetector cell 24b is supplied to the adder 26b via an amplifier 25b. , 26c, the output signal of the photodetection cell 24c is supplied to the other ends of the adders 26a, 26c via the amplifier 24c, and the output signal of the photodetection cell 24d is supplied to the adder via the amplifier 25d. 2
6b and 26d.

The output signal of the adder 26a is a differential amplifier OP
2 and the non-inverting input terminal of the differential amplifier OP2 is supplied with the output signal of the adder 26b.
As a result, the differential amplifier OP2 includes the adders 26a, 26
A signal related to the focus point is supplied to the focusing control circuit 27 in accordance with the difference b. The output signal of the focusing control circuit 27 is supplied to the focusing drive coil 12, and the laser light is
The above is controlled so that it is always in just focus.

The output signal of the adder 26d is a differential amplifier OP
1, and the output signal of the adder 26c is supplied to the non-inverting input terminal of the differential amplifier OP1.
As a result, the differential amplifier OP1 includes the adders 26d and 26d.
A track difference signal is supplied to the tracking control circuit 28 in accordance with the difference c. The tracking control circuit 28 creates a track drive signal according to the track difference signal supplied from the differential amplifier OP1.
However, for the glass substrate 1, a track drive signal is generated according to a control signal supplied from the CPU 30.

The track driving signal output from the tracking control circuit 28 is the driving coil 1 in the tracking direction.
1 is supplied. The track difference signal used in the tracking control circuit 28 is supplied to the linear motor control circuit 8.

The supply of the track drive signal to the drive coil 11 causes the objective lens 10 to move gradually from groove to groove while the glass substrate 1 makes one rotation. .

When the tracking control circuit 28 moves the objective lens 10, the linear motor control circuit 8
Moves the linear motor 6, that is, the optical head 5, so that the objective lens 10 is located near the center position in the optical head 5.

Further, a data generation circuit 14 is provided at a stage preceding the laser control circuit 13. This data generation circuit 14 stores header data as recording data in 8-15.
It has a modulation circuit that performs conversion (modulation) by a code conversion method or the like.

The focusing device has a focusing control circuit 27 and a tracking control circuit 2 respectively.
8, a D / A converter 31 used to transfer data between the linear motor control circuit 8 and the CPU 30 is provided.

The laser control circuit 13, focusing control circuit 27, tracking control circuit 28, linear motor control circuit 8, motor control circuit 4, data generation circuit 14 and the like are controlled by a CPU 30 via a bus line 29. The CPU 30 has an operation panel 3
A predetermined operation is performed in accordance with a cutting start instruction from the control unit 4 and a program stored in the memory 33.

With the cutting device as described above,
After the cutting process is completed by melting the photoresist of the glass substrate 1 in accordance with the recording data for the entire surface, development and conductivity are performed to produce a glass master. Using this glass master, a stamper made of nickel or the like is created by electroplating or the like.

Using this stamper, an optical disk (RAM) 51 for recording and reproducing data recorded on grooves and lands by injection molding or the like is prepared. The recording / reproducing optical disk (RAM) 51 is configured such that preformat data (for example, 54 bytes) of a header portion is formed for each recording area (for example, 38688 bytes) of ECC block data as shown in FIG. Has become.

As shown in FIG.
Byte synchronization code part VFO1, two synchronization code parts VFO2 of eight bytes each, three ID detection synchronization codes of two bytes each, three address parts ID of five bytes each
1, ID2, ID3, and 1-byte postamble PA areas.

As shown in FIG. 5, this header section is composed of a plurality of pits 101 and a groove 102.
The disk is preformatted as shown in the figure, and the edge in the tangential direction of the disk on one side is co-linear with one edge of the groove 102, and the other edge protrudes into the land 103, and the position of the center line 103a of the land 103 Exists.
As a result, the pit 101 in the header portion is
Are asymmetric with respect to the center line 102a of FIG.

Next, an optical disk apparatus for recording data on the recording / reproducing optical disk 51 and reproducing the recorded data will be described with reference to FIG. Since the configuration is almost the same as that of the cutting device, the same portions are denoted by the same reference numerals and description thereof will be omitted.

However, before the recording of the ECC block data, a 12-byte synchronization code portion VFO3 is recorded,
At the time of reproduction, the PLL is corrected with the recorded synchronization code. In portions other than the header portion, as shown in FIGS. 7A and 7B, recording data as recording marks is recorded on each of the groove and the land.

That is, the output signals of the adders 26c and 26d are supplied to the land / groove discriminating circuit 40. The land / groove discriminating circuit 40 discriminates whether the reproduction beam corresponds to a land or a groove based on output signals from the adders 26c and 26d.
For example, as shown in FIG. 8, the land / groove discriminating circuit 40 includes a low-pass filter 41 that low-passes the output from the adder 26c, a low-pass filter 42 that low-passes the output from the adder 26c, and an offset to the output of the low-pass filter 41. Adder 43 for adding, and adder 43
And the output of the low-pass filter 42.

For example, as shown in FIG. 9A, when the reproduction beam traces the groove, the output of the adder 26c is output by the pit in the header as shown in FIG. 9B. , And the output of the adder 26d decreases slightly as shown in FIG. 9 (c).

In this case, when the pit in the header portion is reproduced by the reproduction beam, the detection state of the photodetector 24 is as follows.
This is as shown in FIG. For example, the pit images correspond to the entirety of the detection cells 24a and 24d,
A part of the pit image corresponds to the detection cells 24b and 24c.

As shown in FIG. 11A, when the reproduction beam is tracing the land, the output of the adder 26c is output by the pits in the header as shown in FIG. 11B. , And the output of the adder 26d is
As shown in (c) of FIG.

In this case, when the pits in the header portion are reproduced by the reproduction beam, the detection state of the photodetector 24 is as follows.
This is as shown in FIG. For example, the detection cells 24a and 24d correspond to a part of the image of the adjacent pit, and the detection cells 24b and 24c correspond to almost the entire image of the pit.

Therefore, as shown in FIG. 5, when the reproduction beam 104 is tracing the land 103, the output of the adder 26c is output by the pit 101 of the header part, as shown in FIG.
As shown on the left side of (a) of FIG. 2, the output of the adder 26d decreases slightly as shown on the left side of (b) of FIG.
It greatly decreases. As a result, as shown on the left side of FIGS. 12C and 12D, the output Va of the adder 43 is larger than the output Vb of the low-pass filter. As shown on the left side, a land determination signal (H level) is output to the CPU 30.

Further, as shown in FIG.
When the track 05 is tracing the groove 102, the output of the adder 26c is output by the pit 101 in the header part as shown in FIG.
As shown on the right side of FIG.
The output of 6d decreases slightly as shown on the right side of FIG. As a result, as shown on the right side of FIGS. 12C and 12D, the output Va of the adder 43 is smaller than the output Vb of the low-pass filter.
4 to the right side of FIG. 12E, a groove determination signal (L level) is output to the CPU 30.

Thus, the CPU 30 can record data or reproduce data according to the land / groove determination signal from the land / groove determination circuit 40.

In such a configuration, the same address is reproduced during land reproduction and groove reproduction.
By simultaneously generating the land / groove discrimination signal, it is possible to discriminate between the land and the groove, and the CPU can also discriminate at the same time.

With the above configuration, it is possible to reproduce a pit having a large signal amplitude during land / groove reproduction, and it is also possible to generate a land / groove discrimination signal.

It should be noted that each of the photodetecting cells 24a,.
The sum signal of the output of 4d, that is, the output signal from the adder 26e, reflects the change in the reflectance from the pits (recording data) formed on the grooves and lands of the track. This signal is supplied to the data reproducing circuit 18, where the E of the ID to be recorded is recorded.
An access permission signal for the CC block is output, and reproduction data for the ECC block of the ID to be reproduced is output.

The reproduced data reproduced by the data reproducing circuit 18 is subjected to an error correction using an error correction code ECC provided by an error correction circuit 32, and then, via an interface circuit 35, an optical disk control as an external device. The data is output to the device 36.

The data generation circuit 14 outputs recording data to the laser control circuit 13 when recording data. The data generation circuit 14 is supplied with recording data to which an error correction code (ECC) has been added by the error correction circuit 32. The recording data from the control device 46 as an external device is supplied to the error correction circuit 32 via the interface circuit 45 and the bus 20.

The error correction circuit 32 converts the 32 Kbytes of recording data supplied from the control unit 46 into horizontal and vertical error correction codes (ECC) for recording data in sector units (16 sectors) every 4 Kbytes. And a sector ID and a synchronization code,
ECC block format data is generated.

Next, a description will be given of a process for recording data in a state where the land and the groove are determined. For example, an address ID as an ECC block number for recording data is transmitted from the optical disk control device 36 to the CPU 3 via the interface circuit 35 and the bus 29.
0 is supplied.

The CPU 30 determines a track number corresponding to the ECC block number, and according to the track number, the linear motor control circuit 8 and the tracking control circuit 2
8 is controlled. Thereby, the laser light from the optical head 5 moves to the vicinity of the track corresponding to the track number.

In this state, the data reproducing circuit 18 reads the address part ID, and outputs the read result to the CPU 3.
0, and when it matches the address ID to be accessed supplied from the optical disk control device 36 as an external device via the CPU 30, an access permission signal is output to the data generation circuit 14.

Thus, when the access permission signal is supplied, the data generation circuit 14 converts the recording data supplied from the error correction circuit 32 into the recording ECC block format data obtained by adding the ECC block synchronization code to the recording data. After conversion, the recording data is converted (modulated) by an 8-15 code conversion method or the like and output to the laser control circuit 13. The laser control circuit 13 generates a laser beam by driving the semiconductor laser oscillator 19a by the data generation circuit 14, thereby forming pits on the optical disk 51.

Next, a description will be given of a process for reproducing data in a state where the land and the groove are determined. For example, an address ID as an ECC block number for reproducing data is transmitted from the optical disk control device 36 to the CPU 3 via the interface circuit 35 and the bus 29.
0 is supplied.

The CPU 30 determines the track number corresponding to the ECC block number, and according to the track number, the linear motor control circuit 8 and the tracking control circuit 2
8 is controlled. Thereby, the laser light from the optical head 5 moves to the vicinity of the track corresponding to the track number.

In this state, the data reproducing circuit 18 reads the address part ID according to the read signal of the data from the optical disk 51, outputs the read result to the CPU 30, and outputs the read result to the CPU 30.
When the address matches the address ID supplied from the CPU 6 through the CPU 30, the subsequently supplied data is read as reproduced data and demodulated by inverse conversion of 8-15 code by a demodulation circuit (not shown) to generate an error. Output to the correction circuit 32.

The error correction circuit 32 corrects the error using the error correction code ECC given to the supplied reproduction data, and then performs the interface correction.
Via the optical disk control device 36 as an external device.

The CPU 30 reads the read address ID.
Does not match the address ID to be accessed, the access processing is performed again in the same manner as described above. As described above, by recording address pits that are not symmetrical with respect to the center line of the groove on the optical disc, a reproduced signal of the address pit can be obtained stably both when reproducing the land and when reproducing the groove. A discrimination signal can be obtained at the same time.

[0060]

As described above in detail, according to the present invention, an optical disk master manufacturing apparatus and an optical disk master capable of reliably reproducing an address both when reproducing a groove and when reproducing a land. An original disk manufacturing method, an optical disk creating device, an optical disk creating method, and an optical disk reproducing device can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a cutting device for explaining an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a laser generator.

FIG. 3 is a diagram for explaining generation of a groove, generation of an address pit, and a modulation signal.

FIG. 4 is a diagram for explaining preformat data in a header portion.

FIG. 5 is a diagram for explaining a configuration of a pit in a header section.

FIG. 6 is a block diagram showing a schematic configuration of an optical disk device.

FIG. 7 shows a record in which data is recorded in a groove and a land;
FIG. 3 is a diagram showing an example of data recording on a reproduction optical disc.

FIG. 8 is a diagram showing a schematic configuration of a land / groove determination circuit. .

FIG. 9 is a diagram illustrating an output example of an adder when a reproduction beam traces a groove.

FIG. 10 is a diagram showing an example of a detection state of a photodetector when a pit in a header portion is reproduced by a reproduction beam.

FIG. 11 is a diagram showing an output example of an adder when a reproduction beam traces a land.

FIG. 12 is a diagram for explaining output waveforms of each unit in the land / groove discriminating circuit at the time of land tracing and groove tracing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Glass substrate 10 ... Objective lens 13 ... Laser control circuit 19 ... Laser generating part 24 ... Photodetector 26a, 26b, 26c, 26d ... Adder 30 ... CPU 40 ... Land / groove discriminating circuit 51 ... Optical disk

Claims (9)

[Claims] 1. A rewritable type in which data is recorded or recorded data is reproduced using both concentric or spiral grooves and lands, and has a header portion made up of address data at predetermined intervals in advance. In a master manufacturing apparatus for manufacturing a master used for creating an optical disc, a groove having a predetermined width is formed on the master, and a header portion is formed by pits formed asymmetrically with respect to the center line of the groove. An apparatus for manufacturing a master of an optical disc, characterized by comprising means. 2. A rewritable type in which data is recorded or recorded data is reproduced using both concentric or spiral grooves and lands, and has a header portion made up of address data at predetermined intervals in advance. In a master disc manufacturing apparatus for manufacturing a master disc used for producing an optical disc, a groove having a predetermined width is formed on the master disc, and one edge of a pit constituting a header portion in the tangential direction of the disc is the same tangent as one edge of the groove. An optical disk master manufacturing apparatus, characterized in that the pit has a forming means formed so that the other edge of the pit in the disk tangential direction is substantially tangential to the land center axis. 3. A rewritable type in which data is recorded or recorded data is reproduced by using both concentric or spiral grooves and lands, and a header portion composed of address data is provided at predetermined intervals in advance. In the manufacture of a master used for making an optical disc, a groove having a predetermined width is formed in the master, and a header portion is formed by pits which are asymmetrically formed with respect to the center line of the groove. Method for producing an original master of an optical disc. 4. A rewritable type in which data is recorded or recorded data is reproduced by using both concentric or spiral grooves and lands, and a header portion composed of address data is provided at predetermined intervals in advance. In manufacturing a master used for making an optical disc, a groove having a predetermined width is formed in the master, and one edge of a pit constituting a header portion in the tangential direction of the disk is in the same tangential direction as one edge of the groove. Wherein the other edge of the pit in the tangential direction of the disk is formed substantially on the tangential direction of the center axis of the land. 5. A master disk having a predetermined width is provided on a master disk used for producing a rewritable optical disk on which data is recorded or recorded data is reproduced using both concentric or spiral grooves and lands. Manufacturing means for manufacturing a rewritable optical disc master by creating pre-pit data consisting of address data with pits formed asymmetrically in one piece with respect to the center line of the groove at predetermined intervals, First producing means for producing a rewritable optical disk stamper by using the master produced by the producing means; and a first producing means for producing a rewritable optical disk by using the stamper produced by the first producing means. 2. An optical disk producing apparatus, comprising: (2) a producing means. 6. A master having a predetermined width is provided on a master disk used for producing a rewritable optical disk on which data is recorded or recorded data is reproduced using both concentric or spiral grooves and lands. And the edge of one side in the disk tangential direction of the pit constituting the header portion at a predetermined interval is in the same tangential direction as the one side edge of the groove, and the other edge of the pit in the disk tangential direction is substantially Manufacturing means for manufacturing a rewritable optical disk master formed on the tangential direction of the land center axis, and first manufacturing for manufacturing a rewritable optical disk stamper using the master manufactured by the manufacturing means Means, and second creating means for creating a rewritable optical disk using the stamper created by the first creating means. An optical disk producing apparatus, characterized in that: 7. A master disk having a predetermined width is provided on a master used for producing a rewritable optical disk in which data is recorded or reproduced data is recorded using both concentric or spiral grooves and lands. And pits formed asymmetrically with respect to the center line of the groove at predetermined intervals to create pre-pit data consisting of address data to produce a rewritable optical disc master. A rewritable optical disk stamper is created using the master disc, and a rewritable optical disk is created using the created stamper. 8. A master disk having a predetermined width is provided on a master disk used for producing a rewritable optical disk in which data is recorded or reproduced data is recorded using both concentric or spiral grooves and lands. And the edge of one side in the disk tangential direction of the pit constituting the header portion at a predetermined interval is in the same tangential direction as the one side edge of the groove, and the other edge of the pit in the disk tangential direction is substantially A rewritable optical disk master is formed on the tangential direction of the land center axis, a rewritable optical disk stamper is created using the manufactured master, and rewritable using the created stamper. A method for producing an optical disk, comprising: creating an optical disk of a shape. 9. A concentric or spiral groove having a predetermined width is formed, and a header portion is formed by asymmetrically formed pits with respect to a center line of the groove, and the header portion is formed by using both the groove and the land. An optical disc reproducing apparatus for reproducing a rewritable optical disc in which data is recorded or in which recorded data is reproduced, irradiating means for irradiating the optical disc with laser light, reflected light from the optical disc by irradiation of the irradiating means The detection means having two areas separated by a dividing line parallel to the tangential direction of the optical disc and the detected light quantity guided to the two areas detected by the detection means are compared with each other. Determination means for determining whether the position irradiated with the laser beam is a groove or a land; Optical disk reproducing apparatus, characterized in that.