JP2005174465A - Mastering apparatus, disk manufacturing method, disk type recording medium, disk reproducing apparatus, and disk reproducing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve efficiency of a mastering process and to stabilize reading of second information at the time of reproduction, in a disk type recording medium in which the second information (copyright protecting information) is superimposed on first information and recorded. <P>SOLUTION: Recording of the first information is performed by forming a pit string by irradiating an original disk with a first laser beam, while the second information as well as the first information is multiplex-recorded by converging the second laser beam and irradiating a position deviated in the direction of a radius of the original disk of the pit string with it. Thereby, an electroacoustic optical element (light deflector) for recording the second information by wobble of pits conventionally is not required, an exposing time for the original disk is shortened and manufacturing efficiency is improved. Also, at the time of reproduction, reading of such the second information is stabilized by discriminating the value based on a result in which a signal recorded based on the second laser beam is read a plurality of times and integrated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a mastering apparatus that performs mastering of a disc-shaped recording medium such as a CD (Compact Disc) or a DVD (Digital Versatile Disc), and manufacturing of a disc-shaped recording medium such as a CD or DVD by performing such mastering. The present invention relates to a disc manufacturing method. The present invention also relates to a disc-shaped recording medium such as a CD or a DVD, and a disc reproducing apparatus for reproducing the disc-shaped recording medium.

Japanese Patent Laid-Open No. 9-81938 JP-A-11-66739 JP 2000-242929 A JP 2002-197671 A JP 2000-195049 A

  For example, in a compact disc (CD), an IFPI (International Federation of the Phonographic Industry) is provided on the inner peripheral side of an area where audio signals and signals used by a user such as TOC (Table Of Contents) are recorded. ) There is one in which an area called a code is recorded. This code is engraved with a code indicating a manufacturer, a factory, a disk number, etc. for the purpose of preventing unauthorized copying such as so-called pirated copies.

The codes indicating the manufacturer, manufacturing place, disk number, etc. recorded in this way could be recognized visually. For this reason, when reproducing a CD or the like, the reproducing apparatus cannot read these codes.
In other words, the content of such an IFPI code cannot be reflected in the operation control of the playback device. Moreover, since the contents of the IFPI code can be visually confirmed as described above, the code itself is easily copied.

On the other hand, conventionally, a write-once optical disc that allows a user to easily make a copy of a CD, a DVD, or the like is also commercially available. For example, if a disk commercially available as a CD-R (Recordable) and an apparatus corresponding to the disk are used, digital information recorded on the CD can be copied as it is with a simple operation.
Under such circumstances, there are cases where copying is performed infringing on the copyright that should be protected by the Copyright Act, and there is a problem that the copyright holder cannot obtain a reward that should be obtained properly.

Therefore, conventionally, as a technique for solving such a problem, for example, when information used by a user such as an audio signal is the first information, the first information is used as information such as copyright protection. The second information is recorded in a superimposed manner.
As such a technique, conventionally, for example, a part of a large number of information pits is arranged such that the center line is displaced in the radial direction, and these are periodically and intermittently arranged on the information track in units of data blocks of the recording signal An optical disk in which a plurality of optical disks are arranged is proposed.

  As another example, the information pit row is moved from the center line to the track radial direction over a track length that causes a signal variation that can be detected within the tracking error signal band in a part of a specific radius region of the disk. There has been proposed an optical disk with an illegal copy prevention function that forms a displaced pit row displaced in the direction (see, for example, Patent Document 1).

  Further, conventionally, in the optical record carrier on which the first information as the main information and the second information relating to the control information for reproducing the first information are recorded, the first information is based on the second information. When the information is reproduced, the decrypted first information is not directly included, but third information different from the first and second information is associated with the second information. A recorded optical record carrier has been proposed (see Patent Document 2).

  As another example, there is provided a data recording medium in which first data is recorded by sequentially repeating pits and lands by a length that is an integral multiple of a length corresponding to a predetermined basic period, and the track of the pits is recorded. A data recording medium has been proposed in which the second data is recorded by the displacement from the track center in a direction crossing the direction, and the displacement is within a predetermined amount within a range not to be off-tracked (Patent Document). 3).

Further, conventionally, the recording track is composed of continuous lands or grooves, and a pit is formed on the recording track based on the main data, whereby a recording medium on which the main data is recorded has a predetermined on the recording track. Proposing an optical recording medium on which the additional data is recorded by displacing the pits formed at a distance away from each other by a predetermined amount in the direction orthogonal to the center line in the track direction of the recording track based on the additional data (See Patent Document 4).
In addition, in the invention shown by this patent document 4, it is described that the said displacement amount exists in the range of 20 nm-100 nm (refer Claim 5 in literature).

According to the prior art as listed above, the second information is recorded by the lateral displacement (wobble) of the pits. Such information recording by wobble is a technique that can be realized only in a mastering apparatus that exposes an optical disc master.
That is, information recorded by wobble cannot be recorded by a write-once type device such as a CD-R. For this reason, for example, if information by wobble is recorded on the master disk and checked for existence at the time of reproduction, an illegal disk copied by a write-once apparatus represented by CD-R or the like is eliminated. Is possible.

  However, the above-described prior art has a problem that wobble must be performed with a sufficiently large width so that information recorded by wobble can be reliably detected. This is to prevent deterioration of the signal-to-noise ratio (SNR) of the signal for detecting wobble.

  For example, in the prior art described in Patent Document 4, it is necessary to create a disc with a relatively large wobble amount so that the wobble amount is 20 nm to 100 nm. In such a large displacement, the presence of wobble is confirmed by observing with an electron microscope or the like. For this reason, there is a problem that the content of the wobble is analyzed and there is a high risk that illegal copying is possible.

By the way, as a technique generally employed when the SNR is poor as described above, it is conceivable to lengthen the pit row as the wobble area and remove noise with a low-pass filter. However, in this case, in an actual optical disc reproducing apparatus, the tracking servo is designed so that the position of the light spot is aligned with the wobble center. For this reason, when the wobble area is lengthened as described above, the amplitude of the wobble detection signal gradually decreases with the movement of the spot, and the amplitude of the wobble detection signal is hardly obtained at the position where the movement of the light spot is completed. It becomes a state.
Therefore, considering the action of the tracking servo in this way, the method of simply increasing the wobble area does not operate effectively. For this reason, when applying the prior art exemplified above, the wobble amplitude has to be increased.

  Therefore, the applicant has previously proposed a further improvement plan. That is, the main data is recorded by the length and interval of the pits along the track, and the sub-data is recorded by the displacement of the pits in the inner and outer circumferential directions with reference to the track center of the track. The pit is displaced corresponding to the result of arithmetic processing of the sub data and a predetermined binary number sequence (see Patent Document 5).

  In an optical disc to which the present invention is applied, when detecting information recorded by wobble, integral detection is performed using a predetermined binary number sequence. In the present invention, one bit of copyright protection information is allocated and recorded in one frame of a CD, for example. One frame has a length equivalent to 12 mm on the disc. By integrating and detecting the reproduction signal in such a long section, it is possible to sufficiently detect even a wobble recorded as a relatively small amplitude. It becomes.

  As a result, depending on the prior art disclosed in Patent Document 5, it is possible to significantly reduce the pit wobble amount, and to realize practical copyright protection by compensating for the disadvantages of the prior art exemplified above. Is possible.

  By the way, in the conventional examples described so far, the second information such as copyright protection information is recorded by wobbling the pits. When the second information is recorded by wobble in this way, it is necessary to insert an electroacoustic optical element (AOD: Acoustic Optical Deflector) as an optical deflector into the optical path.

However, when such an electroacoustic optical element is inserted into the optical path, there is a problem that the amount of laser light after passing is almost halved compared to the amount of light before passing.
Also, such an electroacoustic optical element (optical deflector) has a slow response speed to the wobble signal, and it is virtually impossible to modulate the wobble signal at high speed.

  Because of these problems, when trying to realize the previous prior art, the rotational speed of the master disc must be set low during cutting, which requires a relatively long time for the cutting process. It was impossible to improve manufacturing efficiency.

  Therefore, in the present invention, in order to solve the above-mentioned problems, for example, when accumulating copyright protection information for preventing unauthorized copying, etc., electroacoustic optics as an optical deflector that causes laser light attenuation. It is an object of the present invention to make it unnecessary to use an element and to reliably read copyright protection information and the like that are recorded in a multiplexed manner.

For this reason, in the present invention, the mastering apparatus is first configured as follows.
That is, first, a first recording means for recording the first digital information is provided by irradiating the disc master with a first laser beam to form a pit row.
Then, the second laser beam is condensed and irradiated to a position shifted in the radial direction of the disc master in the pit row formed by the first laser beam, and thereby, together with the first digital information. A second recording means for multiplex recording the second digital information is provided.

In the present invention, the disk manufacturing method is as follows.
That is, the first recording procedure for recording the first digital information by irradiating the disk master with the first laser beam to form the pit string, and the pit string in the radial direction of the disk master The second laser beam is condensed and irradiated to the shifted position, thereby executing the second recording procedure for multiplexing and recording the second digital information together with the first digital information.

Furthermore, in the present invention, the disk-shaped recording medium is as follows.
That is, the disc-shaped recording medium of the present invention is a disc-shaped recording in which the first modulation signal generated by modulating the first digital information according to the required format is recorded according to the pit length and interval. A medium,
Only one wall surface position of the pit is displaced in a direction orthogonal to the track longitudinal direction, whereby the second digital information is recorded in a multiplexed manner together with the first digital information.

Further, in the present invention, the disc reproducing apparatus is configured as follows.
In other words, first reading means is provided which first modulates the first digital information according to a required format to obtain a first modulated signal recorded as a pit length and interval on the disc-shaped recording medium.
Then, a second reading means is provided for reading the second digital information multiplexed and recorded together with the first modulation signal by the displacement of one wall surface of the pit in the radial direction of the disk.
After that, the second digital information read by the second reading means according to the relative position from the synchronization signal included in the first modulation signal read by the first reading means. A plurality of signal integration means for performing integration and a determination means for decoding a plurality of bits of the second digital information by determining the outputs of the plurality of signal integration means.

Further, in the present invention, the disc playback method is as follows.
That is, a first reading procedure in which first digital information is modulated according to a required format to obtain a first modulated signal recorded as a pit length and interval on a disc-shaped recording medium; A second reading procedure for reading the second digital information multiplexed and recorded together with the first modulation signal is executed by the displacement of one wall surface in the radial direction of the disk.
Then, according to the relative position from the synchronization signal included in the first modulation signal read by the first reading procedure, the second digital information read by the second reading procedure is changed. A plurality of signal integration procedures for integration and a determination procedure for decoding a plurality of bits of the second digital information are performed by determining the outputs of the plurality of signal integration procedures.

According to the present invention, the second digital information is recorded on the disc-shaped recording medium using a laser that is separate from the laser that forms the pit train recorded as the first modulation signal. Is recorded by shifting the wall surface position in the radial direction of the disk.
As a result, in recording the second digital information, an electroacoustic optical element as an optical deflector for deflecting and wobbling the laser light for forming the first modulation signal as in the prior art is provided in the optical path. No need to insert.

  Further, according to the disk reproducing apparatus and method of the present invention described above, the value of each bit constituting the second digital signal is determined after integration is performed at the time of reproduction. The digital signal can be read stably, and at the same time, the second digital information can be recorded on the disk-shaped recording medium by a relatively small wall position displacement.

As described above, in the present invention, when the second digital information (copyright protection information) is multiplexed and recorded together with the first digital information, it is not necessary to insert an optical deflector by an electroacoustic optical element into the recording optical system. It is possible to perform exposure while rotating the disc master at high speed.
According to this, it is possible to improve the manufacturing efficiency of the disc-shaped recording medium by advancing the exposure time for the disc master.

As described above, according to the disk reproducing apparatus and method of the present invention, the second digital signal can be stably read and recorded on the disk-shaped recording medium by a relatively small wall displacement. Is possible.
Since the second digital signal can be recorded with a relatively small wall displacement in this way, for example, in a write-once apparatus such as a CD-R, such a disc-shaped recording medium of the present invention is used. Even if the first digital information recorded in (1) can be copied, the second digital information can be prevented from being recorded. That is, it is possible to make it difficult to create an illegal copy (pirated) disk.
Further, in this case, if the displacement of the wall surface can be made small as described above, the analysis of the second digital information using means such as an electron microscope can be made difficult. Making a copy disc can be difficult.

That is, according to the present invention as described above, it is possible to improve the manufacturing efficiency and provide a strong copyright protection function for the disc-shaped recording medium on which the copyright protection information as the second digital information is multiplex-recorded. Can do.
Then, the second digital information recorded in this way can be read stably.

Hereinafter, the best mode for carrying out the invention (hereinafter referred to as an embodiment) will be described.
The disc-shaped recording medium of the embodiment is realized, for example, as a disc called CD (Compact Disc) or DVD (Digital Versatile Disc), a high-density disc (Blu-ray Disc) that has been developed in recent years, or the like.
Specifically, it is an optical disk having a diameter of 12 cm, and under the condition of a combination of a laser having a wavelength of 405 nm (so-called blue laser) and an objective lens having an NA of 0.85, an emboss pit with a depth of about λ / 4, for example. Playback-only data is recorded. Recording / reproduction is performed at a track pitch of 0.32 μm and a linear density of 0.12 μm / bit.

  The process for manufacturing the disk as described above is roughly divided into a so-called master process (mastering process) and a disk forming process (replication process). The master process is a process until the completion of a metal master (stamper) used in the disc making process, and the disc making process is a process for mass-producing an optical disc as a duplicate using the stamper.

Specifically, in the master process, so-called mastering is performed, in which a photoresist is applied to a polished glass substrate, and pits and wobbles are formed on the photosensitive film by exposure with a laser beam.
When the mastering is completed, after performing predetermined processing such as development, information is transferred onto the metal surface by, for example, electroforming, and a stamper necessary for duplicating the disk is created.
Next, using this stamper, the information is transferred onto the resin substrate by, for example, the injection method, a reflective film is formed on it, and then processed into the required disk form to complete the final product. To do.

FIG. 1 is a block diagram showing an example of the internal configuration of a mastering apparatus 1 according to the present embodiment that performs a master process (mastering) in the disk manufacturing process as described above.
In this figure, the disk master 15 is first rotated by a spindle motor 14 shown in the figure. The rotation of the spindle motor 14 is controlled by the spindle servo circuit 13 and is controlled to be driven at a rotation speed corresponding to the rotation control method employed.

Digital information such as music and / or video recorded on the disc master 15 is supplied from the first signal source 2 shown as first information SA.
In addition to the first information SA, the second information SB is supplied from the second signal source 6 shown in the present embodiment as information for preventing illegal copying such as so-called pirated copies.
The second information SB includes, for example, ID information set so as to be unique to each disc master 15, information relating to the manufacturing factory, date of manufacture, information for controlling whether copying is possible, and the like. Digital information.

In the present embodiment, the first information SA is encrypted and recorded by the encryption circuit 3 described below using the second information SB as key information. In other words, the second information SB is used to prevent unauthorized copying.
In the present embodiment, in order to avoid complication of explanation, an example in which the second information SB is composed of 32-bit data will be described below. However, in practice, the number of bits is further increased. As a result, it is possible to complicate decoding and make illegal copying more difficult.

  The encryption circuit 3 encrypts the first information SA supplied from the first signal source 2 using 32-bit data supplied as the second information SB from the second signal source 6 as key information. For example, any encryption method such as DES (Data Encryption Standard) may be employed as the encryption method.

  An ECC (Error Correcting Code) circuit 4 adds an error correction code to the output of the encryption circuit 3 and performs an interleaving process on the data to which the error correction code is added in this way. As a result, even when a defect or a defect occurs on a disc created based on the master disc 15, data can be reliably reproduced.

The 1-7PP modulation circuit 5 modulates the input data from the ECC circuit 4 by the RLL (1, 7) PP modulation method (RLL: Run Length Limited / Parity preserve Prohibit rmtr (repeated minimum transition run-length)). I do.
The 1-7PP modulation circuit 5 generates a pit modulation signal SD such that the level 1 and the level 0 change in a cycle that is an integral multiple of a predetermined cycle. At this time, the DC component is suppressed in the pit modulation signal SD, and a synchronization pattern is periodically inserted.

The additional modulation circuit 7 detects the synchronization pattern from the pit modulation signal SD subjected to RLL (1-7) PP modulation and performs timing synchronization so as to convert the second information SB into the pit wall displacement signal SBW. Configured. Then, by outputting the pit wall displacement signal SBW obtained in this way to the second laser 8 as shown in the figure, the first information SA and the second information SB are simultaneously recorded on the disc master 15.
The internal configuration of the additional modulation circuit 7 will be described later.

The first laser 9 is composed of a gas laser, for example, and emits a laser beam L0 to the optical modulator 10. The optical modulator 10 is configured by an electro-acoustic modulator (Acoustic Optical Modulator) or the like, and turns on / off the laser beam L0 at a high speed according to the level of the pit modulation signal SD supplied from the 1-7PP modulation circuit 5 described above. Turns off and outputs as laser beam L1.
The optical path of the laser beam L1 is bent at an angle at which the laser beam L1 is emitted with respect to the recording surface of the disk master 15 by the mirror 11 shown in the figure, passes through the objective lens 12 and the half mirror 16, and then onto the recording surface of the disk master 15. It is designed to collect light.

The second laser 8 is made of, for example, a semiconductor laser, and emits a laser beam L2 when the pit wall displacement signal SBW supplied from the additional modulation circuit 7 is level 1. Conversely, when the pit wall displacement signal SBW is level 0, the laser beam L2 is not irradiated.
The laser beam L2 corresponding to the pit wall displacement signal SBW irradiated from the second laser 8 is mixed with the laser beam L1 by the half mirror 16, and is condensed on the surface of the disk master 15 by the objective lens 12.

The mirror 11, the half mirror 16, and the objective lens 12 are configured to sequentially move in the disk radial direction in synchronization with the rotation of the disk master 15 by a thread mechanism (not shown).
That is, the condensing positions of the laser beam L1 and the laser beam L2 are sequentially shifted in, for example, the outer circumferential direction of the disc master 15, and thereby, the disc master 15 has a spiral track (pit array). ) Is formed.

  Here, the intensity of the laser beam L1 irradiated by the first laser 9 is set higher than that of the laser beam L2 irradiated by the second laser 8. Therefore, the length and interval of the pit rows formed on the disc master 15 are determined by the laser beam L1 having higher intensity. Thereby, the length and interval of the pit train can be set according to the pit modulation signal SD.

In this case, the irradiation position on the disc master 15 of the laser beam L2 irradiated by the second laser 8 is shifted from the irradiation position of the laser beam L1 in the direction perpendicular to the track. .
This is shown in FIG. 2 below. In this case, a light spot formed by the laser beam L2 on the disk master 15 with respect to a light spot (spot 1) formed by the laser beam L1 on the disk master 15 is shown. The position of (spot 2) is slightly shifted downward in the figure.

As a result, when the laser beam L2 is irradiated (when the pit wall displacement signal SBW is level 1), the position of the lower wall surface of the pit is displaced. For example, in the case of FIG. 2 described above, as for the three pits (P1, P2, P3 in the figure) recorded when SBW = 1, the lower wall surface position is displaced downward by Δ.
In this way, a pit row whose pit wall surface position is displaced according to the pit wall displacement signal SBW is recorded on the disc master 15. That is, the length and interval of the pit row represent the first information SA, and the wall surface position difference below the pit reflects the second information SB.

  In FIG. 1, a disc master 15 exposed by the laser beams irradiated by the first laser 9 and the second laser 8 described above is generated as a stamper by being developed and plated as described above. . Then, by transferring information onto the resin substrate using this stamper, forming a reflective film on the resin substrate, and performing processing such as processing into a required disk shape, the disk 100 as the present embodiment is generated. Will be.

FIG. 3 shows an internal configuration example of the additional modulation circuit 7 shown in FIG.
First, in FIG. 3, the pit modulation signal SD is a signal output from the 1-7PP modulation circuit 5 shown in FIG. 1, and this pit modulation signal SD is synchronized in the additional modulation circuit 7 as shown in the figure. Input to the pattern (FS) detection circuit 20.
That is, the first information SA subjected to the RLL (1-7) PP modulation process is input to the synchronization pattern detection circuit 20.

  Here, RLL (1-7) PP modulation processing is performed, and a signal recorded on the above-described master disc 15 (disc 100) has a configuration as shown in FIG.

  FIG. 4 is a diagram schematically illustrating the configuration of signals recorded on the disc 100 (disc master 15) in the present embodiment. As shown in this figure, a pit row is recorded on the disc 100 in a spiral or concentric circle. As shown in FIG. 4A, the pit train recorded here is divided into units called blocks each having a predetermined length. Each block is added with an error correction code and address information, and is a minimum unit from which data can be read independently.

  Each block is divided into six frames named “Frame 0” to “Frame 5” as shown in FIG. 4B. As shown in FIG. 4C, different synchronization patterns are added to the heads of these frames, and the frame number can be determined by the type of these synchronization patterns. Further, as shown in FIG. 4C, each synchronization pattern is configured such that data of 220 bytes follows.

As the synchronization pattern as described above, for example, a 30-bit length pattern as described in Japanese Patent Laid-Open No. 2000-68846 is used.
As an example of this synchronization pattern, as shown in FIG. 5, for example, different synchronization patterns are used for six different frames (FS0 to FS5 in the figure). In the example shown in FIG. 5, a fixed pattern in which the first 24 bits of the 30-bit length forming the synchronization pattern is a sync body is assigned. That is, the bit indicated by “#” in the figure is determined in accordance with the value of the immediately preceding bit, and then the sync pattern is assigned by allocating a fixed pattern in which the inversion interval of 9T-9T follows the inversion of “010”. Detection is possible.
Further, subsequently, different 6-bit sync IDs (sync IDs) are allocated, and each frame of FS0 to FS5 can be identified by this sync ID.

In FIG. 3, the synchronization pattern detection circuit 20 detects the above six types of synchronization patterns (FS0 to FS5) included in the pit modulation signal SD, and latches them as frame number information FN as shown in FIG. ) 21.
The synchronization pattern detection circuit 20 activates the reset pulse RS at the timing when the synchronization pattern is detected, and resets the counts of the first counter 22 and the second counter 23. As a result, the count values of the first counter 22 and the second counter 23 are both reset to “0” immediately after detection of the synchronization pattern, and the values are sequentially increased.

The second counter 23 starts from the count value “0” and increases the value in units of channel clocks, and the count value becomes “0” again as the count value becomes a predetermined value. It works to be. In this case, “164” is set as the predetermined value, and the second counter 23 is a 165-ary counter.
On the other hand, the first counter 22 is configured to count up by one each time the count value of the second counter 23 overflows and returns to “0”.
As a result, the output PN of the first counter 22 shown in the figure is reset to “0” immediately after the synchronization pattern, and thereafter the value is incremented by 1 every 165 clocks.

The reference table 24 includes a memory element such as a ROM (Read Only Memory). In the ROM provided in the reference table 24, a reference for outputting a predetermined select signal SLCT according to the frame number information FN supplied from the illustrated latch 21 and the value of the output PN of the first counter 22 is provided. Information 24a is stored.
The reference table 24 outputs a select signal SLCT output by referring to the reference information 24a based on the frame number information FN and the output PN to the analog switch 28 shown in the drawing. .
The structure of the reference information 24a stored in the reference table 24 will be described later.

The second information SB shown in FIG. 1 is input to a CRC (Cyclic Redundancy Check) addition circuit 25. The CRC adding circuit 25 is configured by a flip-flop, an exclusive OR, and the like, and adds a CRC code to the input second information SB.
In this case, the CRC adding circuit 25 inputs the second information SB composed of 32 bits and adds a 16-bit CRC code for error detection. That is, here, the second information SB is 48-bit information (B0 to B47) in total.
By adding a CRC code in this way, it becomes possible to detect and remove errors during reading.

The copyright protection information (second information SB) B0 to B47 with the CRC code and 48 bits as described above is input to the serial / parallel (SP) conversion circuit 26 as shown in the figure.
The serial / parallel conversion circuit 26 is constituted by a flip-flop or the like, and outputs 48-bit information input as 48 parallel output signals in 1-bit units. Each of the 48 outputs is branched and supplied to the corresponding non-inverting amplifier 27A (0 to 47) and inverting amplifier 27B (0 to 47) as shown in the figure.

The non-inverting amplifier 27A (0 to 47) is configured to output a level of “1” or “0” according to the logic of the input signal.
Conversely, the inverting amplifier 27B (0 to 47) outputs the input signal after inverting the logic of the input signal. Therefore, the output of the inverting amplifier 27B (0 to 47) is configured to output a level of “1” or “0” with logic inverted from the input signal.

The analog switch 28 is 1 based on the value of the select signal SLCT supplied from the reference table 24 out of the signals input from the non-inverting amplifier 27A (0 to 47) and the inverting amplifier 27B (0 to 47). The signal is selected.
Then, the voltage of “1” or “0” level thus selected is output as the pit wall displacement signal SBW.

  According to the above configuration, depending on the additional modulation circuit 7, one of the copyright protection information B 0 to B 47 according to the passage of time (relative position) from the synchronization pattern detected from the pit modulation signal SD as described below. A bit is selected. At the same time, two outputs of positive logic and negative logic as the pit wall displacement signal SBW are obtained corresponding to one bit of B0 to B47 selected in this way.

Here, operations obtained in the mastering apparatus 1 configured as described above will be described with reference to the following FIGS.
6 and 7 are diagrams for explaining the transition of the value of the select signal SLCT for designating selection by the analog switch 28 shown in FIG. 6 and 7 schematically show the frames FS0 to FS6 forming one block shown in FIG.
First, in the present embodiment, as described above, 220 bytes of data are recorded for each frame. Therefore, in this case, if the synchronization pattern portion is excluded, 220 × 8 = 1760 bit information is recorded in each frame as shown in FIGS.
At this time, in the RLL (1-7) PP modulation method, since 2-bit data is converted into 3-bit, the length of each frame is 1760 × 3/2 = 2640 clocks as shown in the figure. .

  When a frame sync located at the head of each frame shown in FIGS. 6 to 7 is input, the synchronization pattern detection circuit 20 shown in FIG. 3 detects this frame sync. At this time, as described above, there are six different frames (FS0 to FS5) in the present embodiment, and the synchronization pattern detection circuit 20 recognizes the sync ID of the detected frame sync. Accordingly, the value of the frame number information FN recognized by the synchronization pattern detection circuit 20 in this way is output from the latch 21 to the reference table 24.

At the same time, when the frame sync is detected as described above, the reset pulse RS is also output from the synchronization pattern detection circuit 20, and the count value of the first counter 22 is reset to “0” accordingly. Is done. That is, “0” is output to the reference table 24 as the value of the output PN of the first counter 22.
At this time, the count value of the second counter 23 is also reset to “0” in response to the reset pulse RS. Then, the second counter 23 starts counting in 165 based on the channel clock described above.

  Thereafter, the first counter 22 increments the count value by 1 every time the count value of the second counter 23 makes a round (the channel clock changes 165 times). That is, the value of the output PN of the first counter 22 is incremented by 1 every 165 clocks out of the clock “2640” for one frame described above. Therefore, in this case, the value of the output PN is By 2640 ÷ 165 = 16, 16 values from 0 to 15 are taken as shown in the figure.

Then, the output PN having a value from 0 to 15 and the frame number information FN output from the latch 21 are input to the reference table 24. In the reference table 24, these output PNs are output. And a predetermined select signal SLCT based on the frame number information FN.
Thus, a plurality of bits constituting the second information SB are allocated in correspondence with a predetermined position in the frame based on the relative time from the time when the synchronization pattern is detected.

As such bit allocation method, as shown in FIGS. 6 to 7, the 48-bit information (B0 to B47) constituting the second information SB is converted into six frames (one frame). FS0 to FS5) are allocated in order.
Here, since each of these 48-bit information is converted into two signal outputs by the non-inverting circuit 27A and the inverting circuit 27B as described in FIG. 3, the 1-bit information is composed of two signals. Will be.
Therefore, when 48-bit information is allocated in order from FS0 as described above, first, 16 signals from [B0A, B0B... B7A, B7B] are allocated to the frame FS0 as shown in the figure. Will be. Further, signals up to [B8A, B8B... B15A, B15B] following B7B are allocated to the subsequent FS1 frame.
Thereafter, in the frame FS2 shown in FIG. 6C, [B16A, B16B... B23A, B23B], and in the frame FS3 shown in FIG. 7A, [B24A, B24B ... B31A, B31B], [B32A, B32B... B39A, B39B] is assigned to the frame FS4 shown in FIG. 7B, and [B40A, B40B... B47A, B47B] is assigned to the frame FS5 shown in FIG. Become.

Here, as described above with reference to FIG. 4, a plurality of bits constituting the second information SB can be allocated to predetermined positions in each frame in the reference table 24 as described above. Reference information 24a is stored.
The reference information 24a stored in the reference table 24 has a structure as shown in FIG.

In FIG. 8, as the reference information 24a, the output signal (B0A) of the non-inverting amplifier 27A is associated with the combination of the frame number information FN output from the latch 21 and the output PN of the first counter 22 as shown. To B47A) and one of the output signals (B0B to B47B) of the inverting amplifier 27B is assigned.
When the frame number information FN is “0” so that the signals are allocated in the order shown in FIGS. 6 to 7, the values corresponding to the output PN values “0 to 15” are as shown in the figure. [B0A, B0B... B7A, B7B] are assigned to the signals, and the signals are assigned in order according to the value of the frame number information FN and the value of the output PN so as to continue thereafter. is there.
As a result, as shown in FIGS. 6 to 7, as the value of the select signal SLCT output from the reference table 24, [B0A, B0B... B47A, B47B] are sequentially selected every 165 clocks. It will be something to go.

  As the value of the select signal SLCT transitions as described above, a signal corresponding to the value of the second information SB is output as the pit wall displacement signal SBW output from the analog switch 28. The pit wall displacement signal SBW as a signal output in this way is input to the second laser 8 as described with reference to FIG. 1, and the laser beam L2 is turned on / off based on this. As a result, the second information SB is recorded on the disk master 15 as a displacement of one wall surface of the pit.

FIG. 9 is a diagram schematically showing the operation when the second information SB is recorded by the wall surface displacement based on the pit wall displacement signal SBW in this way.
In this figure, when the value of the frame number information FN is “0”, that is, as shown in FIG. 9A, the second information SB for 8 bits recorded in the frame FS0 is illustrated. .
In this figure, first, it is assumed that the values of the lower bits B0 to B7 of the second information SB are as shown in FIG. In this case, according to the value “0” of the least significant bit “B0”, the output of the non-inverting amplifier 27A-0 is “0” and the output of the inverting amplifier 27B-0 as described with reference to FIG. Becomes “1”. As a result, the pit wall displacement signal SBW shown in FIG. 9E is output at the “0” level in the first section in which “B0A” is selected as the value of the select signal SLTC shown in FIG. 9C. Next, “1” level is output in the section in which “B0B” is selected.

Further, according to the value “1” of the lower second bit “B1”, the output of the non-inverting amplifier 27A-1 is “1” and the output of the inverting amplifier 27B-1 is “0”. Accordingly, in this case, a level of “1” is output in a section in which “B1A” is selected by the select signal SLTC, and a level of “0” is output in a section in which “B1B” is selected. It becomes like this.
In this way, a voltage change as shown in FIG. 9E is output as the pit wall displacement signal SBW.

  The pit wall displacement signal SBW shown in FIG. 9E is input to the second laser 8 shown in FIG. 1 as described above. Then, on / off of the laser beam L2 is determined according to the pit wall displacement signal SBW. Accordingly, the lower side wall surface of the pit recorded on the recording surface of the disk master 15 is displaced in a direction perpendicular to the track length direction.

FIG. 9F schematically shows the state of this displacement. For example, in a section in which “B1A” is selected by the select signal SLCT signal, the level “1” is output, so the light spot 2 is lit.
As described above, the light spot 2 has a weak light intensity as compared with the light spot 1 by the laser light L1 from the first laser 9. However, by irradiating with the laser light L1 at the same time, the light spot 2 irradiating the lower wall surface of the pit displaces the lower wall surface position of the pit downward by “+ Δ”.
As a result, as shown in FIG. 9F, in the section in which “B1A” is selected, the lower side wall surface of the pits P1, P2, and P3 moves downward in the figure by the displacement amount “Δ”. Will do.

Further, in the section in which “B1B” is selected by the select signal SLCT, the level “0” is output as the pit wall displacement signal SBW, so that the light spot 2 is not lit. In other words, in this case, the pit lower wall surface is not displaced.
Therefore, the positions of the lower side wall surfaces of the pit rows P4, P5, and P6 formed in this section are formed at the same place as usual without being shifted.

  In this way, the second information SB as the copyright protection information is recorded on the master disc 15 and thus on the disc 100 by slightly shifting or not shifting one wall surface of the pit row.

Subsequently, an optical disc reproducing apparatus 30 that reproduces the disc 100 manufactured by using the mastering apparatus 1 described so far and on which the first information SA and the second information SB are superimposed and recorded will be described with reference to FIGS. Will be described with reference to FIG.
FIG. 10 is a block diagram showing an internal configuration example of an optical disc playback apparatus 30 as an embodiment to which the disc playback apparatus of the present invention is applied.
In FIG. 10, a disc 100 is a disc-shaped recording medium manufactured using the mastering device 1, and as can be understood from the above description, the first information SA and the first information SA The second information SB as the copyright protection information is recorded as the displacement of the wall position on one side of the pit row.
The disk 100 is rotated by a spindle motor 31 shown in the figure. The spindle motor 31 and the optical pickup 32 are controlled by the servo circuit 39 so as to perform predetermined operations.

  The optical pickup 32 converts the light beam reflected from the disk 100 into an electrical signal by a plurality of detectors and outputs the electrical signal. The matrix amplifier (MA) 33 generates a track error signal TK, a focus error signal FS, a push-pull signal PP, and a reproduction signal HF by performing a matrix operation on a plurality of electrical signals detected by the optical pickup 32. Output.

  The track error signal TK and the focus error signal FS are supplied to the servo circuit 39 and used for controlling the focal position of the optical pickup 32 and the like. Further, the reproduction signal HF is supplied to the binarization circuit 34, and is used for detection of information recorded on the disc 100 as a pit modulation signal SD.

  The push-pull signal PP is supplied to a band-pass filter (BPF) 40 to remove unnecessary low-frequency and high-frequency noise components, and then supplied to the second decoding circuit 41. The second decoding circuit 41 reads out the second information SB recorded on the disc 100 by the wall surface displacement as described above based on the push-pull signal PP. The internal configuration of 41 will be described later.

  The binarization circuit 34 binarizes the supplied reproduction signal HF to generate a binarized signal BD. The binarized signal BD is also supplied to the 1-7PP decoding circuit 35, the PLL circuit 38, and the second decoding circuit 35 described above.

The 1-7PP decoding circuit 35 performs reverse operation of RLL (1-7) PP modulation to restore the recorded information, and supplies it to the ECC circuit 36.
The ECC circuit 36 corrects an error based on an ECC (Error Correcting Code) added in encoding at the time of recording.
The PLL circuit 38 generates a channel clock CK based on the supplied binary signal BD. The channel clock CK generated in this way is supplied to each part in the figure and used as an operation clock.

The CRC check circuit 42 receives the 48-bit second information SB read out by the second decoding circuit 41, and is added to the second information SB by the CRC adding circuit 25 described in FIG. An error check is performed based on the code.
In the CRC check circuit 42, when it is determined that the second information SB is correctly read by the error check, the CRC code (16 bits) is excluded from the 48-bit information (B0 to B47). The first 32 bits as the copyright protection information are sent to the decryption circuit 37.
Then, the decryption circuit 37 decrypts the encryption performed at the time of recording using such second information SB, restores the first information SA, and reproduces and outputs it.
That is, this makes it possible to decrypt the first information SA that has been encrypted using the copyright protection information as the second information SB as a key, and to reproduce it normally.

  Note that if the CRC check circuit 42 determines that an error is included by error check, the encryption of the first information SA cannot be correctly canceled. Therefore, in this case, for example, this is notified to a system controller (not shown), each part of the optical disk playback device 30 is controlled by this system controller, the system is reset, and the copyright protection information B0 to B47 is detected again. And so on.

FIG. 11 is a block diagram illustrating an internal configuration example of the second decoding circuit 41 illustrated in FIG. 10.
First, in this figure, the push-pull signal PP supplied from the bandpass filter 40 shown in FIG. 10 is input to the AD converter 51 shown in the figure and converted into a digital signal.

Also, the binarized signal BD shown in FIG. 10 is input to the synchronous pattern (FS) detection circuit 58 shown in the figure. The synchronization pattern detection circuit 58 performs the same operation as the synchronization detection circuit 20 shown in FIG.
That is, six types of synchronization patterns (FS0 to FS5) included in the binary signal BD as the RLL (1-7) PP modulation signal are detected, and these are held in the latch 59 as frame number information FN. Further, the reset pulse RS is activated at the timing when the synchronization pattern is detected as described above, and the count values of the first counter 60 and the second counter 61 shown in the figure are reset.
That is, in this case, the first counter 60 and the second counter 61 also have a value of “0” immediately after the synchronization pattern, and the values are sequentially increased.

  The first counter 60 and the second counter 61 also perform the same operation as that shown in FIG. That is, the second counter 61 is a 165-ary counter, and the first counter 60 is configured to increment the count value by 1 each time the count value of the second counter 61 returns to “0”.

The reference table 62 also outputs a predetermined value as the select signal SLCT shown in the figure in accordance with the frame number information FN and the value of the output PN of the first counter 60, as shown in FIG.
In this case as well, the select signal SLCT is inputted to the analog switch 52 shown in the figure, and this allows the analog signal to be analogized at the same timing as the recording described above with reference to FIGS. One of the signals (B0A, B0B... B47A, B47B) input to the switch 52 is selected.
In this case, the reference information stored in the reference table 62 is equivalent to the reference information 24a shown in FIG.

Thereby, for example, at the time of recording, at the timing when the area where the “B0A” terminal of the analog switch 28 shown in 3 is selected is reproduced, the output of the push-pull signal PP from the AD converter 51 shown in FIG. The analog switch 52 appears at the terminal “B0A”.
Similarly, at the time of recording, for example, the push-pull signal PP obtained by reproducing the area where “B0B” is selected and recorded is displayed at the “B0B” terminal of the analog switch 52. .
In this way, in the analog switch 52, 48-bit information converted into the pit wall position displacement at the time of recording can be obtained based on the input push-pull signal PP.

Each of the inverting elements 53-0 to 53-47 shown in the figure is connected to the terminals B0B to B47B in the analog switch 52, and is configured to invert the signal polarity and to output the signals.
At this time, for example, when the least significant bit of the second information SB inputted as the push-pull signal PP is “0”, the “B0A” and “B0B” terminals of the analog switch 52 are connected. According to the description of FIG. 9, the obtained signals correspond to the wall surface positions of “0” and “+ Δ”, respectively.
Here, since the DC component of the push-pull signal PP is removed by the band pass filter 40, the voltages of “−Δ / 2” and “+ Δ / 2” are actually “B0A” and “B0B”, respectively. It will be obtained at the terminal. According to the inverting element 53 connected as described above, in this case, the detected voltage of “+ Δ / 2” obtained at the terminal “B0B” is inverted, and “−Δ / 2” is output. Become so.
That is, by performing such an inversion operation, when the value of the bit as the second information SB is “0”, only a negative polarity signal can be obtained. On the contrary, when the bit value as the second information SB is “1”, only a signal corresponding to the positive polarity is obtained.

  The signals obtained in this way are added by the adder circuits 54-0 to 54-47 shown in the drawing, and the added signals are added to the corresponding digital integration circuits 55 (0 to 47). ).

The digital integration circuits 55-0 to 55-47 integrate the addition signals (V0 to V47) supplied from the corresponding addition circuits 54, respectively.
In this case, each digital integration circuit 55 performs integration on the signal that has been inverted as described above. That is, for example, when the logic of the recorded bit is “0”, the signal “−Δ” as the addition result of the addition circuit 54 is integrated in each integration circuit 55. Accordingly, when the logic of the recorded bit is “0”, the digital integration circuit 55 can obtain a negative value.
On the other hand, if the bit logic is “1”, for example, the signal “Δ” as the addition result of the adder circuit 54 is integrated, so that a relatively positive value is obtained. It will be obtained.

  In this embodiment, the noise component mixed in the recording / reproducing process is expected to be averaged to have a relatively small amplitude as a result of the integration operation in the digital integration circuit 55 as described above. is there.

Each determination circuit 56 (0 to 47) counts the number of times integrated in each of the digital integration circuits 55, and when the number of integration exceeds a predetermined number, the output of the corresponding digital integration circuit 55 is output. The polarity of the integrated output (S0 to S47) obtained is determined. That is, each determination circuit 56 outputs a logic “1” when the output of the digital integration circuit 55 is positive, and outputs a logic “0” when it is negative. .
The digital data (B0 to B47) output from each determination circuit 56 is supplied to the parallel / serial (PS) conversion circuit 57 and output as the second information SB.

Here, in the case of the present embodiment, the predetermined value for the number of integrations set in each determination circuit 56 is set to satisfy a predetermined value n> 64. That is, the digital integration circuit 55 integration operation as described above is repeated until, for example, a reproduction signal having the same frame number information FN is input at least 64 times.
As described above, in this example, the second information SB is recorded so as to be completed in a section of 6 frames (one block shown in FIG. 4). Therefore, when the predetermined value n is set as described above, the integration operation is repeatedly performed until the push-pull signal PP for at least 64 blocks is input.
As a result of performing the integration over the section of at least 64 blocks by each digital integration circuit 55 in this way, the optical disk reproducing device 30 of this embodiment removes the influence of noise and records with a pit wall position displacement of 5 nm or less. The determined second information SB can be reliably determined.

Here, conventionally, a displacement of at least 20 nm or more is necessary as the wobble amount Δ. On the other hand, in the present embodiment, as described above, the displacement amount Δ of one side wall surface of the pit can be set to 5 nm or less.
However, with such a small amount of displacement, there is a concern that the signal-to-noise ratio (SNR) of the push-pull signal PP is considerably reduced as compared with the conventional case.
However, at this time, assuming that noise is randomly generated, the value of SNR increases in proportion to the square root of the number of integrations. Therefore, in the optical disc reproducing apparatus 30 of the present embodiment, the digital integration circuit 55 is configured to perform integration at least 64 times as described above, and a disc that can obtain only a push-pull signal smaller than the conventional one, This makes it possible to reliably detect with an SNR equal to or higher than that of the prior art.

In the present embodiment, the second information SB is allocated and recorded in one block as shown in FIGS. 6 to 7 and then recorded in a plurality of blocks as described above. The That is, depending on this, the same information as the second information SB is recorded across a plurality of blocks on the disc 100.
As a result, when the second information SB recorded in this way is reproduced by the optical disc reproducing apparatus 30, a specific frame causes a dropout, a bit slip, etc. due to a defect on the disc and becomes unreadable. Even in this case, although this portion is reflected as a slight noise level, the second information SB (copyright protection information) can be correctly reproduced.
That is, according to the present embodiment, the second information SB can be read stably and reliably without being affected by defects or pits missing in the recording signal on the disc 100. It will be.

As described above, in the present embodiment, the second information SB recorded as wobble is integrated multiple times during reproduction of the disc 100, so that the amount of wobble displacement on the disc 100 is suppressed to 5 nm or less. It is possible.
Further, as described above, such second information SB is repeatedly recorded on a plurality of blocks on the disc 100. Further, when reproducing the second information SB, the same information repeatedly recorded as described above is read a plurality of times and integrated. Thus, for example, even when a defect or pit is missing at the head of the frame, the second information SB as the copyright protection information can be reliably reproduced.
In other words, depending on the present embodiment, even when the second information SB is recorded with the slight amount of displacement of the pit wall position equivalent to the conventional one, for example, when there is a defect or a missing pit at the beginning of the frame, This second information SB can be reliably reproduced.

Since the second information SB recorded by the slight displacement of the pit wall position as described above does not give any change to the recording signal, the first information SA can be copied as it is. In other words, in this case, even if the encrypted first information SA can be copied, it is difficult to analyze and copy the second information SB superimposed and recorded in order to cancel the first information SA. .
For this reason, the illegally copied disc becomes unreproducible in the optical disc reproducing apparatus 30 because the second information SB is not copied in this way, and only the regular disc is distributed, thereby protecting the copyright. Can be made stronger.

  Further, since the second information SB recorded by the minute pit wall position displacement as described above is difficult to illegally read by, for example, an electron microscope, it is possible to prevent unauthorized copying of the disc.

Further, as described above, depending on the mastering device 1 of this example, the signal as the second information SB is recorded by the displacement of the one side wall surface of the pit row due to the irradiation of the laser beam L2 by the second laser 8, In recording such second information SB, there is no need to insert an optical deflector (electroacoustic optical element) in the optical path as in the prior art.
Thus, since it is not necessary to insert the electroacoustic optical element into the recording optical system, it becomes possible to perform exposure while rotating the master disk 15 at a high speed, thereby improving the manufacturing efficiency of the master disk 15. Can do.

In the above embodiment, the case where the present invention is adapted to the RLL (1-7) PP modulation signal system is taken as an example. However, the present invention is not limited to this, and for example, EFM modulation or RLL (8-16). ) Modulation, RLL (2-7) modulation, etc., and can be applied to almost all modulation methods.
In addition, the method of allocating each bit as each second information SB described in the above embodiment is merely an example, and of course is not limited to this.

  Further, in the above embodiment, each bit of the second information SB is alternately allocated to the positive polarity signal and the negative polarity signal by the non-inverting amplifier 27A and the inverting amplifier 27B. However, it is also possible to configure so as to perform such positive and negative allocation using, for example, a pseudo-random number sequence. This further complicates the recording signal of the second information SB, making it more difficult to create a pirated version.

It is a block diagram which shows the internal structural example of the mastering apparatus as embodiment in this invention. It is a figure which shows typically two laser beam spot positions in embodiment, and the mode of the pit row | line | column formed by this. It is a block diagram which shows the internal structural example of the additional modulation circuit 7 with which the mastering apparatus of embodiment is equipped. It is a figure which shows typically the structure of the modulation signal by a RLL (1-7) PP modulation system. It is a figure which shows the structural example of the synchronous pattern inserted in the said modulation | alteration signal. It is a figure for demonstrating the transition of the value of the select signal SLCT for designating selection by the analog switch 28 shown by FIG. Similarly, it is a diagram for explaining the transition of the value of a select signal SLCT for designating selection by the analog switch 28 shown in FIG. It is a data structure figure which shows the structure of the reference information 24a stored in the reference table 24 shown by FIG. It is a figure which shows typically the operation | movement at the time of recording 2nd information SB based on the pit wall displacement signal SBW. It is a block diagram which shows the example of an internal structure of the disc reproducing | regenerating apparatus as embodiment in this invention. It is a block diagram which shows the example of an internal structure of the 2nd decoding circuit 41 with which the disk reproduction apparatus as embodiment is provided.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Mastering apparatus, 2 1st signal source, 3 Encryption circuit, 4 ECC circuit, 5 1-7PP modulation circuit, 6 2nd signal source, 7 Additional modulation circuit, 8 2nd laser, 9 1st laser, 10 Electroacoustic Modulator (AOM), 11 mirror, 12 objective lens, 13 spindle servo circuit, 14 spindle motor, 15 disc master, 16 half mirror, 20 synchronization pattern detection circuit, 21 latch, 22 first counter, 23 second Counter, 24 reference table, 24a reference information, 25 CRC addition circuit, 26 serial / parallel conversion circuit, 27A (0-47) non-inverting amplifier, 27B (0-47) inverting amplifier, 28 analog switch, 30 optical disk playback device, 31 spindle motor, 32 optical pickup, 33 matrix amplifier, 4 Binarization circuit, 35 1-7PP decryption circuit, 36 ECC circuit, 37 Decryption circuit, 38 PLL circuit, 39 Servo circuit, 40 Band pass filter, 41 Second decryption circuit, 42 CRC check circuit, 51 AD converter , 52 Analog switch, 53 (0-47) Inverting element, 54 (0-47) Adder circuit, 55 (0-47) Accumulator circuit, 56 (0-47) Judgment circuit, 57 Parallel / serial converter circuit, 58 Sync Pattern detection circuit, 59 latch, 60 first counter, 61 second counter, 62 reference table

Claims (12)

A first recording means for recording the first digital information by irradiating the disk master with a first laser beam to form a pit row;
By condensing and irradiating the second laser beam at a position shifted in the radial direction of the disk master of the pit row formed by the first laser beam, a second digital together with the first digital information is provided. A second recording means for multiplex recording information;
A mastering device comprising: Furthermore, a first signal generating means for generating a first modulated signal by modulating the first digital information according to a required format;
Bit selection means for allocating a plurality of bits constituting the second digital information in a unit interval of the same synchronization signal according to a relative position from the synchronization signal included in the first modulation signal;
The first recording means records the first modulated signal generated by the first signal generating means as the first digital information, and
The second recording means is configured to multiplex-record the second digital information by irradiating the second laser beam according to the output of the bit selection means.
The mastering apparatus according to claim 1. A first recording procedure for recording the first digital information by irradiating the disk master with a first laser beam to form a pit row;
A second recording procedure for multiplexing and recording the second digital information together with the first digital information by condensing and irradiating the second laser beam at a position shifted in the radial direction of the disc master of the pit row. When,
The disc manufacturing method characterized by performing these. In the first recording procedure,
A first signal generation procedure for generating a first modulated signal is further performed by modulating the first digital information according to a required format, and the first modulated signal is used as the first digital information. As well as record
In the second recording procedure,
A bit selection procedure for allocating a plurality of bits constituting the second digital information within a unit interval of the same synchronization signal according to a relative position from the synchronization signal included in the first modulation signal; The second digital information is multiplexed and recorded by irradiating the second laser beam according to the value of the bit allocated by the bit selection procedure.
The disc manufacturing method according to claim 3. A first modulation signal generated by modulating the first digital information according to a required format is a disc-shaped recording medium on which the pit length and interval are recorded;
A disc-shaped recording medium in which second digital information is multiplexed and recorded together with the first digital information by only displacing one wall surface position of the pit in a direction orthogonal to the track longitudinal direction.   In accordance with the relative position from the synchronization signal included in the first modulation signal, a plurality of bits constituting the second digital information are allocated within a unit interval of the same synchronization signal, and the value of the allocated bit 6. The disc-shaped recording medium according to claim 5, wherein the displacement of the pit wall surface position is performed according to the above.   6. The disc-shaped recording medium according to claim 5, wherein a displacement amount of the pit wall surface position is 5 nm or less.   6. The disc-shaped recording medium according to claim 5, wherein the first digital information is encrypted using the second digital information as key information. There are a plurality of types of synchronization signals, and the plurality of types of synchronization signals are periodically inserted into the first modulation signal, and the second digital signal is supplied to each of these different synchronization signals. Multiple bits that make up the information are allocated,
The disk-shaped recording medium according to claim 5. First reading means for modulating a first digital information according to a required format to obtain a first modulated signal recorded as a pit length and interval on a disc-shaped recording medium;
Second reading means for reading the second digital information multiplexed and recorded together with the first modulation signal by displacement of one wall surface of the pit in the radial direction of the disk;
A plurality of integrations of the second digital information read by the second reading means in accordance with the relative position from the synchronization signal included in the first modulation signal read by the first reading means. Signal integration means,
Determination means for decoding a plurality of bits of the second digital information by determining outputs of the plurality of signal integration means,
A disc player characterized by that. A first reading procedure in which first digital information is modulated according to a required format to obtain a first modulated signal recorded as a pit length and interval on a disc-shaped recording medium;
A second reading procedure for reading the second digital information multiplexed and recorded together with the first modulation signal by displacement of one wall surface of the pit in the radial direction of the disc;
A plurality of integrations of the second digital information read by the second reading procedure according to the relative position from the synchronization signal included in the first modulation signal read by the first reading procedure. The signal integration procedure of
A determination procedure for decoding a plurality of bits of the second digital information by determining an output of the plurality of signal integration procedures;
A disc playback method characterized in that   12. The disk reproducing method according to claim 11, wherein in the signal integration procedure, integration is performed for each bit constituting the second digital information at least 64 times.

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