JP2001023172A - Information recording device, information recording method, and information recording medium, and information reproducing device and information reproducing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the recording density by recording first data by the repetition of regions with different optical characteristics and recording second data by the local change of the regions and the change in entire width according to the repetition of the regions. SOLUTION: A ROM 18, a digital/analog conversion circuit (DA) circuit 19, a delay circuit 20, and an addition circuit 21 compose a second modulation means for switching a modulation method in reference to a pattern detection result by first and second modulation methods and for modulating an EFM signal SB according to addition information SC that are second data. In a case by the first modulation method, the EFM signal SB is modulated by second addition information to form the local change of a pit of space. On the other hand, in a case by the second modulation method, the EFM signal SB is modulated so that the change in the width of the entire pit can be formed. The change in a first shape is the local change of the pit and the space according to the addition information, and the change in a second shape is the change in the width of the entire pit according to the addition information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording apparatus, an information recording method, an information recording medium, an information reproducing apparatus and an information reproducing method, for example, an optical disk apparatus for reproducing a compact disk (CD) and a digital video disk (DVD). Etc. can be applied. According to the present invention, the first data is recorded by repeating regions having different optical characteristics, and the second data is formed by local changes in these regions and changes in the overall width in accordance with the repetition of the regions. By recording data, the data can be reproduced by a conventional reproducing apparatus, and the recording density can be further improved as compared with the conventional one.

[0002]

2. Description of the Related Art Conventionally, a compact disc has an audio signal modulated by EFM (Eight to Fourteen Modulation).
A pit string is formed in accordance with the EFM signal generated as described above, and an audio signal is recorded.

That is, in a compact disc,
An audio signal is sampled at a predetermined sampling frequency to generate a digital audio signal;
An error correction code (EC
C: Error Correcting Code) is added. In the compact disk, in the subsequent EFM modulation, the digital audio signal and the error correction code are converted into an 8-bit data string, and the 8-bit data is further converted into a 14-bit data. In the compact disk, 3-bit combined data is interposed between the data of the 14-bit string, thereby generating an EFM signal in which 1 byte is 17 bits.

In a compact disk, the laser beam is turned on and off in accordance with the EFM signal to form pits and spaces in sequence, so that the cycle T of the channel clock of the EFM signal is used as a reference cycle, and the reference cycle T Pits and spaces having a length corresponding to an integral multiple of the period are repeatedly formed, whereby a digital audio signal is recorded in units of 0.3 [μm] corresponding to the reference period T. I have.

On the other hand, a compact disk player receives a return beam obtained by irradiating a laser beam to a compact disk and processes the received light to reproduce a signal whose signal level changes in accordance with pits and spaces. A signal is generated. Further, the reproduced signal is binary-identified, the EFM signal generated at the time of recording is demodulated, and the EFM signal is processed corresponding to the processing at the time of recording, thereby reproducing the digital audio signal. In the EFM signal obtained in this way, errors such as defects and dust of the compact disc are generated. In the compact disc player, bit errors are effectively avoided by the error correction code added at the time of recording. It has been done.

[0006]

By the way, in this kind of optical disk, if the recording density can be improved,
To that extent, it is considered that an audio signal with high sound quality, which is higher quality than the conventional one, can be recorded and reproduced. However, in the case of a compact disk, there is a problem that it is difficult to improve the recording density because the recording density is determined by the standard such as the EFM signal.

[0007] One way to solve this problem is to use E
It is conceivable to employ a recording method other than the FM signal. However, in this case, there is a problem that it is difficult to reproduce with a conventional compact disk player.

The present invention has been made in view of the above points, and proposes an information recording apparatus and the like which can be reproduced by a conventional reproducing apparatus and can further improve the recording density as compared with the conventional one. What you want to do.

[0009]

According to the first aspect of the present invention, there is provided an information recording apparatus, wherein a second modulating means modulates a modulation method based on a pattern detection result. The first modulation scheme is switched between the first modulation scheme and the second modulation scheme to modulate the first modulation signal, and the first modulation scheme is adapted to perform the first and / or second modulation in accordance with second data. A modulation method that forms a local change in an area, and the second modulation method is a modulation method that changes the entire width of the first and / or second area according to the second data. I do.

Further, in the invention according to claim 5, in the information recording method, the second modulating step modifies the modulating method based on the pattern detection result with the first modulating method and the second modulating method. Modulating the first modulation signal by switching between the first and second methods, wherein the first modulation method forms a local change in the first and / or second area according to the second data. And the second modulation scheme is a modulation scheme that changes the entire width of the first and / or second area according to the second data.

In the invention according to claim 7, the present invention is applied to an information recording medium, and has a first shape corresponding to a pattern in which the first and second regions are formed for each predetermined pattern detection unit. The second data is recorded by the change and the change of the second shape, and the change of the first shape is a local change of the first and / or the second region according to the second data. , The change in the second shape corresponds to the first data according to the second data.
And / or a change in the overall width of the second region.

In the invention according to a tenth aspect, the present invention is applied to an information reproducing apparatus, wherein a pattern detecting means for detecting a continuous signal level change pattern in the first reproduced data and outputting a pattern detection result, A second decoding unit for decoding the second reproduction data by processing the digital reproduction signal by switching the processing method between the first processing method and the second processing method based on the pattern detection result; To do.

In the invention according to the thirteenth aspect, the present invention is applied to an information reproducing method, and includes a pattern detecting step of detecting a continuous signal level change pattern in the first reproduced data and outputting a pattern detection result. A second decoding step of decoding the second reproduction data by processing the digital reproduction signal by switching the processing method between the first processing method and the second processing method based on the pattern detection result; Be prepared to have.

According to the first aspect of the present invention, applied to the information recording apparatus, the second modulating means changes the modulating method based on the pattern detection result into the first modulating method and the second modulating method. And so as to modulate the first modulation signal,
The first modulation method is a modulation method for forming a first and / or second local change in a region according to the second data, and the second modulation method is a method according to the second data. And the first
And / or a modulation method in which the entire width of the second area is changed, so that the modulation by the second data is set so as not to affect the reproduction of the first data. The first data can be reproduced, and the recording density can be improved by recording the second data.

According to the fifth aspect of the present invention, in the information recording method, the second modulating step may use the first modulating method and the second modulating method based on a pattern detection result. This is a process of modulating a first modulation signal by switching with a modulation system, wherein the first modulation system forms a local change in a first and / or a second area according to second data. Since the second modulation scheme is a modulation scheme that changes the entire width of the first and / or second areas according to the second data, the modulation by the second data is the second modulation scheme. The first data can be made reproducible by a conventional reproducing apparatus by setting so as not to affect the reproduction of the first data, and the recording density can be reduced correspondingly by recording the second data. Can be improved.

According to the seventh aspect of the present invention, the present invention is applied to an information recording medium, and a first pattern detecting unit for each predetermined pattern detection unit is used.
And a first region corresponding to a pattern in which the second region is formed.
The second data is recorded by the change of the shape of the second shape and the change of the second shape, and the change of the first shape is caused by the local change of the first and / or the second region according to the second data. A change in the second shape, the first shape corresponding to the second data,
And / or the change in the entire width of the second area, the recording density can be improved by the amount of the second data recorded, and the recording of the second data is the reproduction of the first data. , So that the first data can be reproduced by the conventional reproducing apparatus.

According to a tenth aspect of the present invention, in the information reproducing apparatus, the pattern detecting means detects a continuous signal level change pattern in the first reproduced data and outputs a pattern detection result. A second decoding means for switching the processing method between the first processing method and the second processing method based on the pattern detection result and processing the digital reproduction signal to decode the second reproduction data. By providing the first optical information recording medium, the first and second areas recorded by repeating the first and second areas in the same manner as the conventional optical information recording medium.
In addition to the reproduction of the data, it is also possible to reproduce the second data recorded by the change of the first and second areas, whereby information having a higher recording density can be reproduced by a conventional reproducing apparatus. The recording medium can be reproduced.

Further, according to the configuration of the thirteenth aspect, a pattern detecting step of applying the information reproducing method to detect a continuous signal level change pattern in the first reproduced data and outputting a pattern detection result. And a second decoding step of decoding the second reproduction data by processing the digital reproduction signal by switching the processing method between the first processing method and the second processing method based on the pattern detection result. In addition to the reproduction of the first data recorded by repeating the first and second areas in the same manner as in the conventional optical information recording medium, the change in the first and second areas It is also possible to reproduce the recorded second data, whereby it is possible to reproduce an information recording medium having a higher recording density so that it can be reproduced by a conventional reproducing apparatus.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(1) Configuration of Embodiment FIG. 2 is a block diagram showing an optical disk recording apparatus according to an embodiment of the present invention. In the manufacturing process of the optical disk according to this embodiment, a mother disk is created by exposing and developing the master disk 2 by the optical disk recording device 1 and then electroforming to create a stamper from the mother disk. . Further, in the optical disk manufacturing process, the disk-shaped substrates are mass-produced from the stamper thus produced, and the optical disks are mass-produced by forming a reflection film and a protective film on each disk-shaped substrate.

That is, in the optical disk recording device 1,
The spindle motor 3 drives the disk master 2 to rotate,
The FG signal generator held at the bottom outputs an FG signal FG whose signal level rises at every predetermined rotation angle. The spindle servo circuit 4 drives the spindle motor 3 in accordance with the exposure position of the master disc 2 so that the frequency of the FG signal FG becomes a predetermined frequency, thereby rotating the master disc 2 at a constant linear velocity. Drive.

The laser 5 is composed of a gas laser or the like, and a laser beam L for exposing the master disc 2 is used.
Inject 1. The optical modulator 6 includes an electroacoustic optical element (AO
M: Acoustic Optical Modulator, and controls the light amount of the laser beam L1 according to the modulation signal SD, thereby outputting a laser beam L2 whose light amount changes according to the signal level of the modulation signal SD.

The mirror 7 bends the optical path of the laser beam L2 and emits the laser beam L2 toward the master disk 2. The objective lens 8 focuses the laser beam L2 reflected by the mirror 7 on the master disc 2. The mirror 7 and the objective lens 8 are sequentially moved in the outer circumferential direction of the disk master 2 by a thread mechanism (not shown) in synchronization with the rotation of the disk master 2, thereby sequentially shifting the exposure position by the laser beam L 2 to the disk master 2.
Is displaced in the outer circumferential direction.

Thus, in the optical disk recording apparatus 1,
A track is formed in a spiral by moving the mirror 7 and the objective lens 8 in a state where the disk master 2 is rotationally driven,
This track is exposed by irradiating a laser beam L2 according to the modulation signal SD.

The signal source 10 is constituted by, for example, a digital audio tape recorder, and sequentially outputs 16-bit parallel audio data SA in the same manner as when a conventional compact disc is created.

The ECC circuit 11 receives the audio data SA, adds an error correction code according to the compact disc standard, and outputs the data. The EFM circuit 12
The output data of the CC circuit 11 is received and processed in the same way as when a conventional compact disc is created, and the EFM signal SB
Is output. That is, the EFM circuit 12 is
1 is output after interleaving processing and EFM modulation processing. At this time, the EFM circuit 12 generates the EFM signal SB by inserting the subcode data based on the TOC information output from the subcode generator. Further, in these processes, the EFM circuit 12 generates the EFM signal SB by inserting a synchronization pattern at a predetermined cycle. Hereinafter, in the EFM signal by the EFM modulation, 17 bits obtained by adding 3 combined bits to 14-bit data will be described as 1 byte.

Thus, in the conventional manufacturing process of a compact disc, the optical modulator 6 is directly driven by the EFM signal SB generated in this way to control the on / off of the laser beam L2, and the master disc 2 is controlled by the laser beam L2. It will be exposed. On the other hand, in the optical disk recording apparatus 1, the additional modulation circuit 13 modulates the EFM signal SB with the information of the signal source 14, and obtains the driving signal S, which is the second modulation signal obtained as a result.
D exposes the master disc 2.

As a result, in the optical disc recording apparatus 1, E
The audio data SA as the first data is recorded by repeating pits and spaces in accordance with the FM signal SA, and the second data as the information of the signal source 14 is recorded on the master disk 2. And can record desired data at a higher density than before. As a result, the ECC circuit 11
A first modulation means for generating a first modulation signal corresponding to repetition of pits and spaces in accordance with audio data SA as first data is constituted.

Here, the signal source 14 includes, for example, the copyright information of the disk, the ID information of the disk, information on the manufacturing factory,
The additional information SC, which is information for controlling the date of manufacture or copying permission / prohibition, is output. The signal source 14 outputs the additional information SC after adding the error correction code. Note that the additional information S
In the case of C, music information, image information, and the like can be assigned. The signal source 14 sequentially outputs the additional information SC in the form of serial data in synchronization with the processing of the additional modulation circuit 13, thereby outputting 1-bit additional information SC for one byte of the EFM signal SB. .

The additional modulation circuit 13 enables the EFM signal SB to be reproduced by a conventional compact disc player.
Further, depending on a dedicated reproducing apparatus, the drive signal SD is generated by modulating the EFM signal SB with the additional information SC so that the additional information SC can be reproduced in addition to the EFM signal SB.

FIG. 3 is a block diagram showing the additional modulation circuit 13 in detail. The additional modulation circuit 13 includes a PL (not shown).
The EFM signal SB is input to the L circuit, where a channel clock synchronized with the EFM signal is generated. Each circuit block of the additional modulation circuit 13 operates based on the channel clock.

The shift register 15 is a 17-bit shift register, takes in the sequentially input EFM signals SB on the basis of the channel clock, and outputs the data as 17-bit parallel data X0 to X16.

The synchronization detection circuit 16 detects a synchronization signal by sequentially taking in the EFM signal SB based on the channel clock and judging a continuous signal level. The synchronization detection circuit 16 outputs a byte delimiter signal SY indicating a byte boundary of the EFM signal SB based on the detection result of the synchronization signal.

The latch 17 receives the byte delimiter signal SY
, The output data of the shift register 15 is latched on a byte-by-byte basis, and data Y0, Y1,..., Y1 of the latch result are latched.
6 is output. Thereby, the shift register 15, the synchronization detection circuit 16, and the latch 17 detect and output a signal pattern appearing in the EFM signal SB in units of 1 byte of the EFM signal SB.

As a result, the shift register 15, the synchronization detection circuit 16, and the latch 17 store the first modulation signal, EFM.
The signal SB constitutes a pattern detecting means for detecting a change pattern of the signal level in the modulated signal and outputting a pattern detection result.

The read only memory (ROM) 18 has
.., Y16 output from the latch 17 are assigned to the lower 17 bits of the address, and added to the address of the most significant bit. Information SC
Is assigned. The read-only memory 18 sequentially outputs the modulated data ZD corresponding to the 17 bits of the EFM signal SB in synchronization with the channel clock in accordance with these addresses. Thereby, the read-only memory 18 outputs the modulation data ZD so that a specific channel determined by the signal pattern of the EFM signal SB can be modulated according to the logical level of the additional information SC.

That is, the digital / analog conversion circuit 19
Converts the modulated data ZD into a digital-to-analog signal and outputs it. The delay circuit 20 delays and outputs the EFM signal SB so as to correspond to the output signal of the digital-to-analog conversion circuit 19. The adding circuit 21 adds the output signal of the delay circuit 20 to the digital / analog conversion circuit 19
Of the read-only memory 1
8 according to the modulation data ZD output from the EFM signal S
The drive signal SD is generated by modulating B.

As shown in FIG. 4, when the disk master 2 is exposed by the drive signal SD generated in this way, the read-only memory 18 is shifted with respect to the cycle T of the channel clock which is the cycle of pit formation. When a pit or space with a period of 7T or more is formed between 1-byte sections (FIGS. 4A1 and 4A2), the center of the longest pit or space among the pits or spaces with a period of 7T or more is set. , So that the pit width becomes narrow (Fig. 4
(B1)) or outputs the modulation data ZD so as to form minute pits with a period T (FIG. 4 (B2)). The read-only memory 18 outputs the modulation data ZD so as to change the signal level of the drive signal SD only during the one-channel clock corresponding to the center.

Thus, in the optical disk recording apparatus 1, if the pits and spaces have a period of 7T or more according to the pattern of the pits and spaces formed on the optical disk, reproduction is performed at approximately the center of the longest pits and spaces. The additional information SC is recorded by locally changing the shape of the pit or space so that the signal level of the signal changes.

On the other hand, when pits or spaces with a period of 7T or more are not formed between 1-byte sections, for example, pits and spaces with a period of 3T are repeated on the master disk 2 (FIG. 4 (A3)). ). Here, in the pits and spaces having a period of 3T, when reproducing with a compact disk player, the shape is locally formed at the central portion, as in the case of a pit or space having a period of 7T or more, due to the beam diameter of the reproducing laser beam. Even if it is changed, this change will be observed as jitter in the reproduced signal.

Therefore, in this case, the read only memory 18
Generates the modulation data ZD such that the entire width of the pits having a period of 6T or less becomes wider.

Thus, in the optical disk recording apparatus 1, the EFM signal SB is changed according to the pattern of the pits and spaces formed on the optical disk, by a local change in the pits or spaces, or by a change in the width of the entire pits. One-bit additional information SC is assigned to one byte as a processing unit and recorded.

When the pits having a period of 6T or less are widened in this manner, the change in the signal level of the reproduced signal starts earlier on the pit start side as compared with the case where the pits are not widened during reproduction. At the end of the pit, the change in the signal level is delayed, and these are observed as jitter. The additional modulation circuit 13 corrects the timing of the corresponding drive signal SD for the pits whose overall pit width is wide by a timing correction circuit (not shown) so as to effectively avoid the occurrence of this kind of jitter. Has been made.

Thus, the read-only memory 18, the digital-to-analog conversion circuit 19, the delay circuit 20, and the addition circuit 21 perform the first modulation method based on the pattern detection result.
And a second modulation means for modulating the EFM signal SB by the additional information SC which is the second data by switching with the second modulation method. In the case of the first modulation method, a local pit or space is formed. The second additional information modulates the EFM signal SB so as to form a change in the width of the entire pit.
The signal SB is modulated.

Thus, in the optical disk produced from the master disk 2, pits and spaces as first and second regions exhibiting different optical characteristics depending on the length of the reference period T substantially integer times are repeated. The first shape change and the second shape change according to the pattern in which pits and spaces are formed for each byte of the FEM signal, which is a pattern detection unit, in which audio data as data No. 1 is recorded. Thus, the additional information as the second data is recorded. The change in the first shape is a local change in pits and spaces according to the additional information, and the change in the second shape. Is formed to be a change in the width of the entire pit according to the additional information.

FIG. 1 is a block diagram showing the optical disk reproducing apparatus 31. The optical disk reproducing device 31 reproduces the optical disk 30 mass-produced from the master disk 2.

That is, in the optical disk reproducing apparatus 31, the spindle motor 32 drives the optical disk 30 to rotate at a predetermined rotation speed. The optical pickup 33 is
Return light obtained by irradiating the optical disk 30 with a laser beam is received by a predetermined light receiving element, and the light receiving result is subjected to current-voltage conversion processing and output. Matrix amplifier 34
Are obtained by calculating the light receiving results to obtain a tracking error signal TK whose signal level changes according to the tracking error amount, a focus error signal FS whose signal level changes according to the focus error amount, pits and spaces of the optical disk 30. A reproduction signal HF whose signal level changes in accordance with. The servo circuit 35 performs tracking control and focus control of the optical pickup 33 based on the tracking error signal TK and the focus error signal FS. Also, the optical disk reproducing device 3
In 1, the spindle motor 32 is driven so that the clock detected from the reproduction signal HF has a predetermined frequency.

The binarizing circuit 36 binarizes the reproduction signal HF at a predetermined slice level and outputs a binarized signal BD. Here, as shown in FIG. 5 in comparison with FIGS. 4 (A1) and 4 (B1), in the reproduction signal HF detected from pits having a period of 7T or more of the compact disk whose pit width does not change at all (FIG. 5 (B ) And (C)), after the signal level starts to change at the start of the pit, it saturates at a constant signal level and changes to the original signal level at the end of the pit.

On the other hand, in this optical disc 30, a reproduced signal HF detected from pits having a period of 7T or more is used.
(FIGS. 5 (D) and (E)), since the pit width is locally narrowed at the center of the pit, similarly, after the signal level starts to change in accordance with the pit start time, The signal level is saturated at a constant signal level, and at the time of the saturation, the signal level temporarily changes to the original signal level side (the signal level side of the space portion). After that, after returning to the original saturation value, the signal level changes to the original signal level corresponding to the end point of the pit. At this time, the pit having a period of 7T or more has a sufficient length as compared with the beam diameter of the reproducing system. The reproduction signal HF crosses the slice level SL at the same timing as when the central portion is not formed narrow.

As shown in FIG. 6 in comparison with FIGS. 4 (A2) and 4 (B2), as shown in FIG. 6, in the reproduced signal HF detected from a space having a period of 7T or more of a compact disc having no small pits (FIG. 6 (B) and (C)), after the signal level starts to change at the start of the space, the signal level saturates at a constant signal level, and returns to the original signal level at the end of the space.

On the other hand, in this optical disc 30, the reproduction signal H detected from the space having a period of 7T or more is used.
In F (FIGS. 6 (D) and 6 (E)), a small pit is formed in the center of the space, so that the signal level starts changing in response to the space start point and then becomes constant. And the signal level temporarily changes to the original signal level side (the signal level side of the pit portion) at the time of the saturation. After that, after returning to the original saturation value, the signal level changes to the original signal level corresponding to the end of the space. At this time, in the space having a period of 7T or more, since it has a sufficient length compared to the beam diameter of the reproducing system, it is binarized by the slice level SL in a normal compact disk player, and any space The reproduction signal HF crosses the slice level SL at the same timing as when no minute pits are formed in the central portion.

As shown in FIG. 7 in comparison with FIGS. 4 (A3) and 4 (B3), in the reproduction signal HF detected from the pits and spaces of the conventional compact disc having the pit width not changed and having a period of 3T. Is (FIG. 7 (B)
And (C)), the signal level starts to change in accordance with the pit start time, and changes to the original signal level in accordance with the pit end time before the saturation value is reached. Similarly, on the space side, after the signal level starts changing, the signal level changes to the original signal level before reaching the saturation value.

On the other hand, in the reproduced signal HF obtained from the optical disk 30 (FIGS. 6D and 6E), the signal is sharply increased in accordance with the pit start time due to the wide pit width. Since the level changes and the pits are formed widely, the signal level of the bottom value in the pits increases. On the other hand, at the point of crossing the slice level SL, the timing of the drive signal SD is corrected and the jitter is corrected by the width of the pit, so that the timing is set to the same as that of a normal compact disk. Also, since the space interval is widened by the amount that this timing is corrected, the peak value in the space portion is
It will be closer to the saturation value side than in the case of a normal compact disk.

In the pits from the period 4T to the period 6T, the signal level suddenly starts to change in response to the pit formation start time in substantially the same manner as described for the period 3T. As in the case of the bottom value, the signal level of the bottom value approaches the saturation value by forming the pits widely.

Thus, in the binarized signal BD generated by the binarizing circuit 36, the 16-bit parallel audio data SA is recorded without recording the additional information SC.
Will be exhibited in the same manner as when only is recorded.

A PLL (Phase Locked Loop) 38 operates on the basis of the binarized signal BD, and outputs a channel clock CK (FIGS. 5A to 7) based on the binarized signal BD.
(A)) is reproduced and output. The decoding circuit 38 sequentially latches the binary signal BD based on the channel clock CK. Further, the decoding circuit 38 performs EFM demodulation and deinterleave processing on the data obtained by the latch, thereby outputting audio data in 8-bit parallel.

The ECC circuit 39 performs an error correction process on the output data of the decoding circuit 38 and reproduces the audio data SA in the optical disk recording device 1. The error in the output data of the decoding circuit 38 is, for example,
This is caused by a defect on 0. Thus, in the optical disc reproducing device 31, this EC
In the reproducing system up to the C circuit 39, a reproducing system similar to a normal compact disk player is formed, so that the optical disk reproducing device 31 reproduces a normal compact disk in place of the optical disk 30 and reproduces audio data. It has been made reproducible. Thus, in the optical disc reproducing apparatus 31, the audio data SA output from the ECC circuit 39 is digital-to-analog converted and an amplifier and a speaker are connected to reproduce the music information from the signal source 10 and enjoy it. be able to.

Thus, the PLL circuit 37 and the decoding circuit 38
Constitutes a first decoding means for reproducing the audio data recorded by repeating the pits and spaces by binary-identifying the reproduction signal HF.

The analog-to-digital conversion circuit 40 performs an analog-to-digital conversion process on the reproduction signal HF based on the channel clock CK to generate an 8-bit digital reproduction signal DX.

The second decoding circuit 41 processes the digital reproduction signal DX to produce the additional information SE recorded by the local change of the pits and spaces and the change of the width of the entire pit described above with reference to FIGS. To play. E
The CC circuit 42 performs error correction processing on the additional information SE reproduced by the error correction code added to the additional information SE, and outputs the result. In the optical disk reproducing device 31, copying of the optical disk 30 and the like are restricted based on the error-corrected additional information SC, which is useful for copyright protection.

FIG. 8 is a block diagram showing the second decoding circuit 41 in detail. The shift register 45 is a 17-bit shift register, and takes in the sequentially input binary signals BD based on the channel clock CK.
It is output as 17-bit parallel data S0 to S16.

The synchronization detection circuit 46 detects a synchronization signal by sequentially taking in the binary signal BD with reference to the channel clock CK and determining a continuous signal level. The synchronization detection circuit 46 outputs a byte delimiter signal SY indicating a byte boundary of the EFM signal SB based on the detection result of the synchronization signal.

The latch 47 outputs the byte delimiter signal SY
, The output signal of the shift register 45 is latched in units of one byte, and the data T0, T1,...
6 is output. Accordingly, the shift register 45, the synchronization detection circuit 46, and the latch 47 detect and output a signal pattern appearing in the reproduction signal HF in units of 1 byte of the reproduction signal HF.

Thus, the shift register 45, the synchronization detection circuit 46, and the latch 47 set the pattern detection period to EFM.
By setting a period corresponding to one byte of the signal, the reproduction signal H
A pattern detecting means for detecting a change pattern of the signal level at F is constituted.

The 17-decimal counter 48 resets the count value CT to 0 by the byte delimiter signal SY, and sequentially counts the channel clock CK. This gives 17
The ternary counter 48 outputs a count value CT indicating the number of channels from the head in one byte of the reproduction signal HF.

The read only memory (ROM) 49
.., T16 output from the latch 47 are assigned to the lower 17 bits of the address, and 17 bits are assigned to the remaining upper bits of the address. The count value CT of the binary counter 48 is assigned.

The read-only memory 49 stores 4-bit parallel latch data P corresponding to these addresses.
1, P2, R1, and R2 are sequentially output. Here, these latch data P1, P2, R1, R2 are data indicating the timing of latching the reproduction signal HF, and in the second decoding circuit 41, the corresponding latches in latches (R) 51 to 54, which will be described later, respectively. Data P1, P2, R
When the logical values of R1 and R2 rise, the digital reproduction signal DX is latched.

Here, the read only memory 49 is shown in FIGS.
The latch data P1, P2 and P3 allow the change of the signal level of each reproduction signal HF described above with reference to FIG.
2, R1 and R2 are output. That is, as shown in FIG. 5F, when the pit width is locally narrowed as shown by comparison with the case where the pit width is not changed at all, the boundary between the channels before and after the narrowed central channel. (Signs P1 and P1 are compared with the latch data.
2), the pit width is reduced so that the changing signal level of the reproduced signal HF can be detected. Further, the latch timing is set at the channel boundary (indicated by reference symbols R1 and R2 in comparison with the latch data) on the side of the channel which is two channels away from the channel boundary indicated by reference symbols P1 and P2, respectively. The signal level of the reproduction signal HF can be detected in a portion where the signal level does not change even if the width is reduced.

In FIG. 6 (F), when a minute pit is formed, as shown by comparison with the case where no space is changed, the channels before and after the center channel to which the minute pit is allocated are shown. Boundary (sign P
1 and P2), the timing of the latch is set to thereby reduce the pit width and change the reproduced signal H
The signal level of F can be detected. Also, the code P1
And the latch timing is set at the channel boundary (indicated by R1 and R2) on the side farther from the center channel by two channels than the channel boundary indicated by P2, so that even if the pit width is reduced, the signal level is reduced. The signal level of the reproduction signal HF can be detected in a portion that does not change.

In FIG. 7 (F), when the entire pit width is changed, as shown by comparison with the case where the pit width is not changed at all, the bit boundaries at the center of the pits (denoted by symbols P1 and P2) The latch timing is set at a bit boundary (indicated by R1 and R2) at the center of the space, so that the amplitude A of the reproduced signal HF can be detected. Note that the read-only memory 49 reproduces the four peak values and bottom values corresponding to the pits and spaces as in the case of the period 3T, for example, when the pits and spaces of the period 4T are repeated. Since it does not appear in one byte of the signal HF, in this case, for example, the timings indicated by symbols P1 and P2 are set to the same timing.

The read-only memory 49 outputs a judgment switching signal SJ for instructing to switch the judgment criterion depending on whether the pit or space is locally changed or when the entire pit is changed in width.

In the second decoding circuit 41, the delay circuit 55
Outputs the digital reproduction signal DX with a delay so as to correspond to the latch data P1, P2, R1, R2 output from the read only memory 49.

The latches 51 and 52 latch the digital reproduction signal DX output from the delay circuit 55 with the latch data P1 and P2, respectively, to
The digital reproduction signal DX is latched and held at the timings described by the corresponding symbols in FIGS. Similarly, the latches 53 and 54 latch the digital reproduction signal DX output from the delay circuit 55 with the latch data R1 and R2, respectively.
The reproduction signal DX is latched and held at the timing described by the corresponding reference numerals in FIGS. 5 (F) to 7 (F).

The addition circuit 56 adds the output data of the latches 51 and 52 to reduce the noise component, while the addition circuit 57 similarly adds the output data of the latches 53 and 54 to reduce the noise component. Remove.

The subtraction circuit 58 subtracts the output data RD of the addition circuit 57 from the output data QD of the addition circuit 56, and thereby, an error signal component different for each signal pattern of the binary signal BD, and a bias appearing in the reproduction signal HF. Eliminate the effects of fluctuations. As a result, when the pits and spaces are locally changed in the output signal of the subtraction circuit 58, the change in the signal level of the reproduced signal HF that fluctuates due to the local change is indicated. When the width of the entire pit is increased, the amplitude of the reproduced signal HF (indicated by the symbol A in FIG. 7) based on the pit width is shown.

The determination circuit 59 switches the determination criterion based on the determination switching signal SJ to identify the output signal of the subtraction circuit 58 in binary, thereby reproducing the additional information SE to which the error correction code is added. That is, when the pattern based on the signal level of the reproduction signal HF is a pattern corresponding to a local change in the pits and spaces, when the output signal level of the subtraction circuit 58 rises above a predetermined signal level, a determination result of logic 1 is output. .

On the other hand, when the pattern based on the signal level of the reproduction signal HF is formed so that the entire width of the pit is wide, a subtraction circuit is used with reference to the amplitude of the reproduction signal detected when the standard pit width is used. The output signal level at 58 is determined. In the determination circuit 59, for example, the reproduced signal HF detected in the same manner from a portion to which no additional information is assigned, such as a lead-in area, a subcode, etc.
Is determined with reference to the signal level of.

Thus, the read only memory 49, the latches 51 to 54, the delay circuit 55, the adders 56 and 57,
The subtraction circuit 58 and the determination circuit 59 switch the processing method between the first processing method and the second processing method based on the detection result of the pattern detection means and process the digital reproduction signal, thereby obtaining the second reproduction data. The second decoding means for reproducing certain additional information is constituted.

(2) Operation of Embodiment In the above configuration, in this embodiment, in the manufacturing process of the optical disk, the disk master 2 is exposed by the optical disk recording device 1 (FIG. 2), and the disk master 2 is exposed. An optical disk 30 is created (FIG. 1), and the optical disk 30 is reproduced by a conventional compact disk player and by a dedicated optical disk reproducing device 31.

In the optical disk manufacturing process (FIG. 1), the 16-bit audio data SA input from the signal source 10 is processed in the same manner as when a conventional compact disk is created, and an EFM signal SB is generated. . Further, additional information SC based on disk copyright information, disk ID information, and the like is sequentially input from the signal source 14 so that one bit corresponds to one byte of the EFM signal SB. The EFM modulation signal SB is modulated. In the manufacturing process of the optical disc, the laser beam L1 is modulated by the drive signal SD generated by the modulation, and the disc master 2 is exposed, whereby the audio data SA and the additional information SC are recorded on the disc master 2.

At the time of modulation by the additional modulation circuit 13, the optical disk recording apparatus 1 (FIG. 3)
The signal SB is sequentially input to the shift register 15 to generate 17-bit parallel data X0 to X16, and these data X0 to X16 are latched by the latch 17 based on the byte delimiter signal SY based on the synchronization signal. As a result, a change pattern of the signal level is detected for one byte of the EFM signal SB.

Further, the data Y0 to Y
16 and read-only memory 18 based on additional information SC
With this access, the modulation data ZD is generated by a modulation method according to the detected pattern, the modulation data ZD is converted into an analog signal, and
The EFM signal SB is modulated by being added to the FM signal SB.

That is, when a pit or space with a period of 7T or more is formed between 1-byte sections with respect to the period T of the channel clock which is the period of pit formation (FIG. 4), the pit or space with a period of 7T or more is used. Of the longest pit or space, the modulation data ZD is generated such that the pit width is narrowed or a minute pit having a period T is formed. Additional information S due to change
Modulation data ZD is generated such that C is recorded on master disk 2.

When a pit or space having a period of 7T or more is not formed in a 1-byte section, the modulation data ZD is generated so that the entire pit becomes wider in the 1-byte section.

As a result, in the optical disc recording apparatus 1, E
The modulation method is set to the first according to the change pattern of the FM signal SB.
When the pits or spaces having a long period are formed, the pits or spaces are formed by a local change of the pits or spaces. The additional information SC is recorded according to the change in the width of.

In such a long pit or space having a period of 7T or more, since the length is sufficiently long compared to the beam diameter of the reproducing system, even if it is locally changed almost at the center, the audio is not affected. There is a feature that does not affect the detection timing of the pit edge which is a data reproduction reference at all. On the other hand, in a pit or space with a period of 6T or less, when a local change is made at the center, the distance from the edge of the pit to the locally changed portion is shorter than the beam diameter of the reproducing system. As a result, this local change affects the timing detection of the edge of the pit, and in a severe case, the length of the pit and the space may be erroneously detected. Incidentally, when the lengths of the pits and the spaces are erroneously detected as described above, it is difficult to reproduce the optical disk created by the disk master 2 using a conventional compact disk player.

On the other hand, when the entire pit width is changed as described above, the deviation of the timing detection of the edge due to the change in the pit width is easily corrected by the timing correction of the modulation signal SD in advance. Can be. As a result, even in a 1-byte period in which only pits and spaces shorter in length than the beam diameter of the reproducing system are formed, audio data can be reliably reproduced by the conventional compact disk player so that the additional information SC
Can be recorded.

Further, by recording in this way, it is possible to reliably allocate and record 1-bit additional information SC to one byte of the EFM signal SB, which is one processing unit of audio data. Thus, for example, the 18-bit audio data is divided into lower 2 bits and upper 16 bits, and the upper 16 bits are recorded by repeating pits and spaces, and the lower 2 bits are recorded instead of the additional information. In this way, the data can be reproduced by a conventional compact disc player, and the audio data having a higher sound quality than the conventional one can be reproduced by a dedicated reproducing device.

That is, in the optical disk recording apparatus 1, after the timing of the drive signal SD thus formed is corrected by a timing correction circuit (not shown), it is used for modulating the laser beam L1. The exposure trajectory corresponding to the repetition of the pits and spaces is sequentially formed on the audio data S.
A is recorded, and the additional information SC is recorded by a local change of the exposure trajectory corresponding to the pit and the space or a change of the entire width.

Further, the master disc 2 exposed in this manner is subjected to processing such as development and electroforming to produce an optical disc 30 (FIG. 1).

In the optical disc 30, in the optical disc reproducing apparatus 31, a laser beam is emitted from the optical pickup 33 and return light is detected, thereby generating a reproduction signal HF corresponding to the repetition of pits and spaces. The signal HF is binarized by the binarization circuit 36, whereby the binarized signal BD corresponding to the EFM signal SB at the time of recording is reproduced. Further, the binary signal B
D reproduces a channel clock CK from the PLL 37. The audio data S recorded by repeating the pits and spaces by the processing of the binary signal BD in the decoding circuit 38 based on this channel clock CK.
A is played.

Here, even in the conventional compact disc, the audio data is recorded by repeating the pits and spaces in the same manner as the optical disc 30, so that in the optical disc reproducing apparatus 31, the reproducing system of the audio data SA is used. Thereby, a conventional compact disc can be reproduced.

The conventional compact disk player has almost the same configuration as the audio data SA reproducing system in the optical disk reproducing apparatus 31, so that the optical disk 30 can also be reproduced by the conventional compact disk player. be able to.

In the optical disk reproducing device 31, the reproduction signal HF is further subjected to analog-to-digital conversion processing with reference to the channel clock CK to generate a digital reproduction signal DX, and this digital reproduction signal DX is recorded in the second decoding circuit 41. Sometimes, the additional information SC is reproduced by being processed by a corresponding process.

That is, in the optical disk reproducing apparatus 31 (FIG. 8), the binary signal BD is sequentially latched in the shift register 45 of the second decoding circuit 41 to generate 17-bit parallel data S0 to S16, and the synchronization signal These data S0 to S16 are latched by the latch 47 based on the byte delimiter signal SY based on
In the pattern detection unit corresponding to one byte of the EFM signal SB, a pattern of a change in the signal level of the reproduction signal HF is detected.

Further, the data T0 to T
16 and a count value C indicating the number of channels in one byte
By accessing the read-only memory 49 by T,
The latch data P1, P2, R1, R2 corresponding to the modulation scheme corresponding to the detected pattern and the determination switching signal S
J, and these latch data P1, P2, R
The additional information SC is reproduced by processing the digital reproduction signal DX based on the decision switching signal SJ based on the determination switching signal SJ by switching the processing method according to the signal level change pattern of the reproduction signal HF so as to correspond to the time of recording. You.

That is, when a pit or space having a period of 7T or more is formed between 1-byte sections, the additional information SC is recorded by a local change in the central portion of the longest pit or space. 5 (FIGS. 5 and 6), the processing method is switched so that a change in the signal level of the digital reproduction signal DX is detected by the local change.

When a pit or space having a period of 7T or more is not formed in a 1-byte section, the additional information SC is recorded so that the pit becomes wider in the 1-byte section. (FIG. 7), the processing system is switched so as to detect the amplitude A of the digital reproduction signal DX based on the pit width.

That is, in the second decoding circuit 41, the latch data P1, P2, R1,.
The digital reproduction signal DX is latched by the latches 51 to 54 at the timing corresponding to R2, and the latched result is averaged by the addition circuits 56 and 57, and then the subtraction circuit 58
When the additional information SC is reproduced due to a local change in pits or spaces, a change in the signal level of the digital reproduction signal DX due to the local change is detected. When reproducing the additional information SC due to a change in the width of the entire pit, the amplitude A of the digital reproduction signal DX corresponding to the pit width is detected.

In the succeeding decision circuit 59, the output signal of the subtraction circuit 58 is binary-identified based on a decision criterion corresponding to the decision switching signal SJ, whereby the additional information is reproduced. As a result, the optical disk reproducing device 31 can reliably reproduce data recorded at a higher density than before.

(3) Effects of the Embodiment According to the above configuration, the first data is recorded by repeating pits and spaces which are areas having different optical characteristics. Accordingly, by recording the second data by the local change of the pits and spaces and the change of the width of the entire pit, the first data can be reproduced by the conventional reproducing apparatus, and further, compared with the conventional one. With higher recording density
And the second data.

At this time, by assigning and recording one bit of the second data to the processing unit of the first data, the data for improving the sound quality of the audio data as the first data is correspondingly allocated. In the case of recording by allocating to the second data, various data are allocated to and recorded on the second data, so that the usability of this kind of optical disk system can be improved.

Further, by processing the digital reproduction signal by switching the processing method according to the change pattern of the signal level in the reproduction signal, it is possible to reliably reproduce the data recorded at high density in this manner.

(4) Other Embodiments In the above-described embodiment, in a pit or space having a period of 7T or more, a period of 6T
In the following case, the case where the additional information is recorded by changing the width of the entire pit has been described. However, the present invention is not limited to this. For example, a pit or space having a period of 6T or more is locally changed to have a period of 5T or less. In such a case, the additional information may be recorded by changing the width of the entire pit.

In the above-described embodiment, the case where the pit width is locally narrowed as the local change of the pit has been described. However, the present invention is not limited to this, and conversely, the pit width is locally reduced. It may be wider.

In the above embodiment, when reproducing additional information based on a change in the width of the entire pit, any additional information such as a lead-in area and a subcode is assigned as a criterion for determining the amplitude A of the digital reproduction signal. Although the case where the signal level of the reproduced signal HF detected in the same way from the unexposed portion has been described as a reference, the present invention is not limited to this. For example, the saturation of the reproduced signal level detected in the land portion and the pit portion Various setting methods can be applied to the criterion, such as when making a determination based on the value.

In the above-described embodiment, a case has been described in which audio data is binarized and reproduced by latching it with a clock. However, the present invention is not limited to this. The present invention can also be widely applied to the case of discriminating and reproducing.

Further, in the above-described embodiment, the case where the additional information is reproduced by comparison with a predetermined criterion has been described. However, the present invention is not limited to this, and the reproduction signal level is determined by the maximum likelihood determination. You may make it reproduce | regenerate.

Further, in the above-described embodiment, the case where the present invention is applied to the case where the audio main signal is recorded by pits and spaces has been described. However, the present invention is not limited to this. It is widely applied to the case where the first and second regions having different optical characteristics with respect to the irradiation of the laser beam are repeatedly formed with a length almost an integral multiple of the predetermined reference length to record this kind of information. be able to.

In the above-described embodiment, a case has been described in which audio data is recorded while maintaining compatibility with a compact disk. However, the present invention is not limited to this, and for example, a DVD (Digital Video Disk) may be used. The present invention can be widely applied to a case where a video signal is recorded while maintaining compatibility. In the case of maintaining compatibility with DVD, video data, which is the first information recorded on DVD, is subjected to 8-16 modulation.

In the above embodiment, EFM
In the case where various data are recorded by signals, the case where additional information is recorded in addition to this data has been described. However, the present invention is not limited to this, and 1-7 modulation, 8-16, 2-7 modulation, etc. It can be widely applied when data is recorded by various modulation signals.

Also, in the above-described embodiment, a case has been described in which the copyright information of the disc, the ID information of the disc, and the like are recorded as the additional information as the second data.
The present invention is not limited to this, and can be widely applied to recording various data such as audio data, image data, and text data.

Further, in the above-described embodiment, a case was described in which the desired data was recorded by exposing the master disc by irradiating a laser beam. However, the present invention is not limited to this, and an electron beam may be used instead of the laser beam. The present invention can be widely applied to a case where desired data is recorded by beam irradiation.

In the above-described embodiment, the case where the present invention is applied to the optical disk apparatus has been described. However, the present invention is not limited to this. The present invention can be widely applied to various information recording devices for recording information, information recording media recorded on the information recording device, and information reproducing devices for reproducing the information recording medium.

[0115]

As described above, according to the present invention, the first data is recorded by repetition of areas having different optical characteristics. By recording the second data based on the change in the overall width, the data can be reproduced by the conventional reproducing apparatus, and the recording density can be further improved as compared with the conventional case.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an optical disc reproducing device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an optical disk recording device corresponding to the optical disk reproducing device of FIG.

FIG. 3 is a block diagram showing a configuration of an additional modulation circuit of the optical disk recording device of FIG. 2;

FIG. 4 is a schematic diagram used for describing an additional modulation circuit in FIG. 4;

FIG. 5 is a signal waveform diagram for explaining a reproduction signal in the optical disk reproducing device of FIG. 2;

FIG. 6 is a signal waveform diagram showing a case where additional information is recorded in a space in comparison with FIG.

FIG. 7 is a signal waveform diagram showing a case where additional information is recorded due to a change in the width of the entire pit in comparison with FIG.

FIG. 8 is a block diagram showing a second decoding circuit of the optical disc reproducing device of FIG. 1;

[Explanation of symbols]

1 ... optical disk recording device, 2 ... master disk, 6 ...
.., Optical modulators, 10, 14... Signal sources, 11... ECC circuits, 12... EFM circuits, 13.
…… optical disk, 31 …… optical disk playback device, 36…
... Binarization circuit, 37 ... PLL, 38 ... Decoding circuit, 4
0: analog-to-digital conversion circuit, 41: second decoding circuit

Claims (15)

[Claims] An information recording medium is irradiated with a recording beam to repeatedly form first and second regions exhibiting different optical characteristics according to a length substantially equal to an integral multiple of a predetermined reference period. An information recording apparatus that records data on the information recording medium; a first modulation unit that generates a first modulation signal corresponding to repetition of the first and second areas according to the first data; Pattern detection means for detecting a pattern of a change in signal level of the first modulated signal and outputting a pattern detection result for each predetermined pattern detection period; and a second input data based on the pattern detection result. A second modulation means for modulating the first modulation signal to generate a second modulation signal, and a beam modulation means for modulating the recording beam based on the second modulation signal. The second modulating means modulates the first modulation signal by switching a modulation method between a first modulation method and a second modulation method based on the pattern detection result; The modulation method is a modulation method that forms a local change in the first and / or second area according to the second data, and the second modulation method is a function according to the second data. An information recording apparatus using a modulation method for changing the entire width of the first and / or second area. 2. The pattern detection period is a period corresponding to a processing unit of the first data, and the second modulating means converts one bit of the second data into one pattern detection period. The information recording apparatus according to claim 1, wherein the second modulated signal is generated by allocating the signal. 3. The constant signal level when the first modulation signal is maintained at a constant signal level for a predetermined period or more during the pattern detection period. The second modulation signal by the first modulation method so as to form a local change in the first and / or second region at a portion corresponding to a substantially intermediate point in the period held in the second modulation signal. If the period during which the first modulation signal is held at a constant signal level during the pattern detection period is less than the predetermined period, the second modulation method is used to perform the second modulation. The information recording apparatus according to claim 1, wherein the information recording apparatus generates a signal. 4. The first modulating means generates the first modulated signal by dividing the first input data by a predetermined bit unit, and wherein the pattern detection period is a period corresponding to the predetermined bit unit. The information according to claim 1, wherein the second modulation unit generates the second modulation signal by allocating one bit of the second data to one pattern detection period. Recording device. 5. An information recording medium is irradiated with a recording beam to repeatedly form first and second regions exhibiting different optical characteristics with a length substantially equal to an integral multiple of a predetermined reference period. An information recording method for recording data on the information recording medium, comprising: a first modulation step of generating a first modulation signal corresponding to repetition of the first and second areas according to the first data; A pattern detection step of detecting a pattern of a change in the signal level of the first modulation signal and outputting a pattern detection result for each predetermined pattern detection period; A second modulation step of modulating the first modulation signal with input data to generate a second modulation signal; and a bead for modulating the recording beam based on the second modulation signal. A second modulation step, wherein the second modulation step switches a modulation method between a first modulation method and a second modulation method based on the pattern detection result. The first modulation scheme is a modulation scheme that forms a local change in the first and / or second area according to the second data, and the second modulation scheme is An information recording method, wherein the modulation method is a modulation method that changes the entire width of the first and / or second area in accordance with the second data. 6. The method according to claim 6, wherein the step of performing the second modulation comprises: when the first modulated signal is maintained at a constant signal level for a predetermined period or more during the pattern detection period. The second modulation method according to the first modulation method so as to form a local change in the first and / or second region at a portion corresponding to a substantially middle point of the period held at the level. A signal is generated, and a period during which the first modulation signal is held at a constant signal level during the pattern detection period is less than the predetermined period. The information recording method according to claim 5, wherein a modulated signal is generated. 7. A first light beam having different optical characteristics depending on the length of a predetermined reference period by substantially an integral number of times by irradiation of a recording beam.
And an information recording medium on which first data is recorded by repeating the second area, wherein a first pattern corresponding to a pattern formed by forming the first and second areas is provided for each predetermined pattern detection unit. The second data is recorded by the change of the shape of the second shape and the change of the second shape, and the change of the first shape is the local of the first and / or the second region according to the second data. An information recording medium, wherein the change in the second shape is a change in the entire width of the first and / or second area according to the second data. 8. The pattern detection unit is a unit corresponding to a processing unit of the first data, and one bit of the second data is allocated to one pattern detection unit. The information recording medium according to claim 7, wherein 9. The method according to claim 1, wherein the change in the first shape is such that the first or second region having a predetermined length or more is formed in the pattern detection unit. The first in an intermediate portion
And / or a local change in a second area, wherein the change in the second shape is the pattern detection unit, and the length of the first and second areas is less than the predetermined length. The information recording medium according to claim 7, wherein: 10. A reproduction signal detecting means for irradiating an information recording medium with a laser beam, receiving return light, and generating a reproduction signal whose signal level changes according to the optical characteristics of the laser beam irradiation position; First decoding means for binary-discriminating a signal to detect first reproduction data; analog-to-digital conversion means for generating a digital reproduction signal by performing analog-to-digital conversion on the reproduction signal; signal level in the reproduction signal Pattern detection means for detecting a pattern of change of the pattern and outputting a pattern detection result; and, based on the pattern detection result, switching a processing method between a first processing method and a second processing method to convert the digital reproduction signal. An information reproducing apparatus comprising: a second decoding unit that decodes second reproduction data by performing processing. 11. The first processing method is a processing of detecting a local change in signal level from the first digital reproduction signal and decoding the second reproduction data, wherein the second processing is performed. The information reproducing apparatus according to claim 10, wherein the method is a process of detecting an amplitude of the first digital reproduction signal and decoding the second reproduction data. 12. The second decoding means: sampling means for sampling the digital reproduction signal at a timing corresponding to the pattern detection result to detect a plurality of sampling results; and subtracting data between the plurality of sampling results. 11. The information reproducing apparatus according to claim 10, further comprising: a subtraction unit that generates the subtraction data; and a determination unit that determines the subtraction data based on a reference value according to the first and second processing methods. 13. A reproduction signal detecting step of irradiating an information recording medium with a laser beam, receiving return light, and generating a reproduction signal whose signal level changes in accordance with the optical characteristics of the laser beam irradiation position. A first decoding step of binary-identifying a reproduction signal to detect first reproduction data; an analog-digital conversion step of generating a digital reproduction signal by performing an analog-to-digital conversion of the reproduction signal; A pattern detection step of detecting a pattern of a change in the signal level of the signal and outputting a pattern detection result; and switching a processing method between a first processing method and a second processing method based on the pattern detection result. A second decoding step of decoding the second reproduced data by processing the digital reproduced signal. Information reproduction method to be used. 14. The first processing method is a process of detecting a local change in signal level from the first digital reproduction signal and decoding the second reproduction data. 14. The information reproducing method according to claim 13, wherein the method is a process of detecting an amplitude of the first digital reproduction signal and decoding the second reproduction data. 15. The second decoding step comprises: sampling the digital reproduction signal at a timing corresponding to the pattern detection result to detect a plurality of sampling results; and subtracting data between the plurality of sampling results. 14. The information reproducing method according to claim 13, further comprising: generating the subtraction data; and determining the subtraction data based on reference values according to the first and second processing methods.