JP2000011379A - Device and method for recording to optical disk, optical disk medium and device and method for reproducing from optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide device and method for recording to an optical disk, the optical disk and device and method for reproducing from it capable of improving recording density by effectively using a detection method such as PP detection without being affected by a low frequency noise. SOLUTION: This optical recorder is constituted of a light modulator 16A as a laser beam position displacement means forming a first modulation signal Vm and a second modulation signal Vn from digital information recorded on the optical disk and displacing a position in the lateral direction of a laser beam Lo according to the first modulation signal Vm and a light modulator 16B as a laser intensity modulation means modulating the intensity of the laser beam Lo according to the second modulation signal Vn. Thus, since the information by the displacement in the lateral direction and the information by the intensity modulation can be superposed and recorded on the same groove, the high density recording is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has the same function as an optical disk recording apparatus used for producing an optical disk such as a compact disk (CD) or a digital video disk (DVD), for example, a CD or DVD. An optical disk recording method for producing an optical disk, for example, an optical disk having the same function as a CD, a DVD, etc., for example, an optical disk reproducing apparatus having the same function as a CD, DVD reproducing apparatus, etc., and a function similar to the CD, DVD reproducing method Can be applied as a reproducing method for realizing the above.

[0002]

2. Description of the Related Art Conventionally, in a compact disc (CD), an audio signal is sampled and converted into a digital signal, followed by adding an error correction code (ECC), and further, EFM (Eight to Fourteen Modulatio).
Recording was performed after n).

In a recording system called EFM modulation,
An 8-bit data string is converted to 17 bits, a signal is generated in which each bit is represented by 1 and 0 at intervals of about 0.3 μm, and a laser beam is turned on / off according to this signal string to form an optical disk medium. The information is recorded by forming a pit row in the pit line.

When decoding a disk recorded by such a conventional method, a laser beam is irradiated onto a pit on the optical disk medium, and the light amount of the light beam diffracted and reflected by the pit is converted into an electric signal by a detector. Then, the EFM signal is decoded bit by bit by discriminating the obtained electric signal into 1 and 0.

[0005]

That is, in the case of a CD, about 0.
It was necessary to determine whether the recorded information was 1 or 0 at minute intervals of 3 microns. Since the determination of 1 or 0 is made using a signal of such a short period, there is a problem that if noise is mixed at that moment, the determination of 1 or 0 is erroneously made. The DVD is also essentially the same except that the recording density is different and the data is changed so as to convert 8-bit data into 16 bits. That is, it is exactly the same that the DVD must determine whether it is 1 or 0 at every minute interval.

Of course, an error correction circuit (ECC circuit) is configured to correct an error so that even if such an error occurs, a finally obtained signal is not affected. However, in order for the error correction circuit to operate sufficiently to correct all errors, the original error rate must be sufficiently low. In other words, although an error correction circuit is provided, some errors are allowed, but it is basically assumed that 1 and 0 can be read correctly with a sufficiently high probability.

As described above, in order to read 1 or 0 information recorded at fine intervals in a CD or DVD,
The signal-to-noise ratio (SNR) needs to be high enough. Therefore, for a CD or DVD, a sufficiently high SN
In order to obtain R, it is necessary to lower the recording density and the reproduction speed, and to improve the quality of the disk.

Next, the frequency characteristics of the SNR will be discussed. In a recording system such as a CD or a DVD, the SNR must be good in almost all frequency bands.
For example, even when noise of a considerably high frequency is mixed, it is necessary to determine whether the noise is 0 or 1 in a short moment, so that the noise cannot be removed by the filter and causes an error. In addition, low-frequency noise can also cause an error if it cannot be distinguished from a signal recorded on a disk. As described above, the conventional recording / reproducing method is designed on the assumption that the SNR is uniform over almost the entire frequency band.

Regarding the frequency characteristics of the optical pickup,
For example, "Prin" published by Adam Hilger Ltd.
ciples of optical disc systems ”(ISBN 0-8
5274-275-3, G. Bouwhuis et al.
There is a commentary on the page. In this book, a method of directly detecting light diffracted and reflected by pits, such as a CD or a DVD, is called CA (Central Aperture) detection.
FIG. 2.12 shown in this book shows theoretical frequency characteristics in the case of CA detection. As is clear from this figure, in CA detection used for CDs and DVDs, it can be seen that the lower the frequency, the greater the amplitude of the reproduced signal. Considering only this fact, the lower frequency must be SNR
Is easy to fall into the illusion of good.

However, it is known that when the quality of a signal obtained from a CD or DVD is analyzed by a spectrum analyzer, noise appears concentrated in a relatively low frequency portion. Various causes can be considered for such a phenomenon that there is much noise at a low frequency. The simplest of these is the influence of dust or dust located on the surface of the disk. On the surface of the disk, the light beam from the optical pickup is far from the focal position, so that a large light spot is formed. For this reason, if dust or dirt adheres to the disk surface, the effect of the low-pass filter is generated by a large light spot. Stretched in size. Therefore, it is considered that dust and dirt located on the surface of the disk mainly generate low frequency noise.

As described above, the SN of the optical disc is
Considering R, it can be seen that the signal amplitude and the noise amplitude differ depending on the frequency. Therefore, it is correct to think that the SNR changes depending on the frequency. In many cases,
Due to the influence of dust and dirt attached to the surface of the disk as described above, a high noise level is often observed particularly at a low frequency, and the low frequency component has a relatively high S level.
It is considered that the NR is often bad. Thus, SN
In spite of the fact that R differs depending on the frequency, in the recording methods so far, almost no frequency characteristics are considered,
High SNR was required in all frequency regions.

[0012] The previously cited document "Principles of optica"
l disc systems] describes PP (abbreviation of Push Pull, which is called push-pull in Japanese) detection as a detection method corresponding to CA detection. PP detection calculates the difference between the light intensity received by the front half of the detector and the light intensity received by the rear half of the detector, among the light that has been diffracted and reflected by the pits and reached the detector. It is. FIG. 2.12 of this book shows frequency characteristics in the case of PP detection. It can be seen that the PP detection characteristic shown in this figure shows that the low frequency component is almost zero. Therefore, in consideration of the frequency distribution of noise specific to the optical disk described above, the PP method that does not detect low-frequency noise is considered to be suitable from the viewpoint of SNR.
Unfortunately, currently used modulation schemes such as EFM are based on the premise that detection is performed using the CA scheme. Therefore, if PP detection is used, the reproduced signal cannot be decoded and cannot be used. Met.

Accordingly, a first object of the present invention is to provide a recording apparatus and a recording method for an optical disk capable of improving a recording density by effectively using a detection method not affected by low-frequency noise such as PP detection. An optical disk, a reproducing apparatus, and a reproducing method are proposed. The applicant has
Patent application by the same inventor as the present applicant (Japanese Patent Application No. 10-1)
No. 24342), the recording information (8 bits) is obtained as the sum of a plurality of orthogonal signals, and this signal is dispersedly recorded as a groove width or groove wobble, so that it is effectively good by integrating during reproduction. We have filed an application for an "optical disk device, an optical disk recording method, an optical disk and an optical disk reproducing method" that can obtain a signal with a high signal-to-noise ratio (SNR).

Next, the second object of the present invention will be described. Japanese Patent Application Laid-Open No. Sho 62-43839 discloses a method in which a groove is recorded instead of a pit, and information is recorded as a shift in the lateral position of the groove. As described in this patent, it is possible to record different information as a position shift in the lateral direction of the groove, unlike the method of recording with “with or without” pits or grooves.

However, information recording by such a lateral shift cannot be used simultaneously with EFM modulation as in the past. In the EFM modulation, information is recorded as "with / without" pits, so that an area where information cannot be recorded as a lateral position shift is created. Further, the recorded information interferes with each other, and it has been impossible to detect each of them independently. Therefore, a recording method using such a lateral shift has not been put to practical use until now.

Therefore, a second object of the present invention is to record information by effectively using a lateral position shift which has not been effectively used so far, thereby improving the recording density. , Optical disk recording device, recording method,
An optical disk, a reproducing apparatus, and a reproducing method are proposed.

[0017]

According to a first aspect of the present invention, a first modulation signal and a second modulation signal are created from digital information recorded on an optical disk, and a first modulation signal and a second modulation signal are generated in the horizontal direction of the laser beam in accordance with the first modulation signal. The optical disk recording apparatus includes: a laser beam position displacement device for displacing the position of the laser beam; and a laser intensity modulation device for modulating the intensity of the laser beam according to the second modulation signal. In this manner, information by lateral displacement of the groove and information by modulation of the width of the groove can be superimposed and recorded on the same groove. A much higher recording density can be realized.

In the invention described in claim 2 and the following, sine waves and cosine waves having different frequencies are used as the first and second modulated signals in the invention described in claim 1 as a plurality of orthogonal signals. As a result, the information to be recorded is concentrated in a frequency region centered on the frequency of the sine wave or cosine wave used for recording. Therefore, it is possible to effectively use the frequency characteristic peculiar to the optical disk, and to realize a high recording density.

According to a fourteenth aspect of the present invention, there is provided a method of recording on an optical disk, wherein first and second recording signals are generated in accordance with information to be recorded, and the first and second recording signals are focused on a disk-shaped recording medium. This is an optical disc recording method in which the position of the light beam is displaced laterally with respect to the track, and the intensity of the converged light beam on the disc-shaped recording medium is changed by a first recording signal. In this way,
Information from lateral displacement and intensity modulation (groove width,
Or equivalent to depth modulation), it is possible to superimpose and record information on the same groove, so that the optical disc recording method according to the present invention achieves a much higher recording density than the conventional one. Becomes possible.

The invention described in claim 15 and thereafter is a recording method in which sine waves and cosine waves having different frequencies are used as the first and second recording signals in the invention described in claim 14. As a result, the information to be recorded is concentrated in a frequency region centered on the frequency of the sine wave or cosine wave used for recording. Therefore, it is possible to effectively use the frequency characteristics peculiar to the optical disk, and it is possible to realize a higher recording density.

An eighteenth aspect of the present invention is an optical disc, wherein a first signal and a second signal superimposed on the same groove are recorded, and the first signal is recorded on a track of the groove. Recorded as a lateral displacement,
The second signal is recorded by changing the width or depth of the groove. That is, in the present invention, two types of information are recorded in one groove, namely, information recorded by shifting the position in the horizontal direction and information recorded by changing the width or depth of the groove, so that high recording as a whole is achieved. Density is achieved.

In the invention described in claim 19 and thereafter, sine waves and cosine waves having different frequencies are used as the first and second signals in the invention described in claim 18. As a result, the recorded information is concentrated in a frequency region centered on the frequency of the sine wave or the cosine wave. Therefore, it is possible to effectively use the frequency characteristic peculiar to the optical disk, and it is possible to realize an optical disk recorded at a high recording density.

According to a twenty-fourth aspect of the present invention, there is provided a first detecting means for obtaining a first detection signal related to a track displacement amount from a laser beam reflected by the optical disk and reached by the detector when reproducing the optical disk. Signal processing means comprising: second detection means for obtaining a second detection signal related to the amount of change in track width or depth; and signal processing means for performing signal processing on the first and second detection signals. The digital information is decoded and output from the output of (i), so that information recorded as a positional shift in the horizontal direction of the track and information recorded as a change in the width or depth of the track are separated. And can be detected. Therefore, the optical disk reproducing apparatus according to the twenty-fourth aspect of the present invention can reproduce a disk recorded at a higher recording density than before.

According to a thirty-first aspect of the present invention, when reproducing an optical disk, a first detection signal relating to a displacement amount of a track is obtained from a light beam reflected by the disk, and a width or depth of the track is further obtained from a laser beam. To obtain a second detection signal related to the amount of change. Further, there is provided an optical disc reproducing method for outputting digital information recorded by subjecting the first and second detection signals thus obtained to signal processing. Therefore, in the present optical disk reproducing method, it is possible to separately detect information recorded as a change in position of a track in the lateral direction and information recorded as a change in the width or depth of a track. Therefore, the optical disk reproducing method according to the thirty-first aspect of the present invention can reproduce a disk recorded at a higher recording density than before.

[0025]

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

FIG. 1 is a block diagram showing an optical disk recording apparatus 1 according to an embodiment of the present invention. The optical disc apparatus 1 exposes a master disc 17 to an information source 10A.
The digital data SA output from the storage device is recorded. Further, in the optical disk device 1, the digital data 10B output from the information source 10B is also multiplex-recorded on the same disk master 17.

In the optical disk manufacturing process, the disk master 17 on which information from the information sources 10A and 10B is multiplex-recorded is developed. Next, a mother disk is created by electroforming the developed disk master 17 and a stamper is created from this mother disk. Further, in the optical disk manufacturing process, a disk-shaped substrate is formed from the stamper thus formed, and a reflection film and a protective film are formed on the disk-shaped substrate to form the optical disk 2.

That is, in this optical disk device 1,
The spindle motor 18 drives the disk master 17 to rotate, and outputs an FG signal FG whose signal level rises at every predetermined rotation angle from an FG signal generation circuit held at the bottom. The spindle servo circuit 19 drives the spindle motor 18 in accordance with the exposure position of the disk master 17 so that the frequency of the FG signal FG becomes a predetermined frequency, so that the disk master 17 has a predetermined rotation speed. Is driven to rotate.

The recording laser 15 is constituted by a gas laser or the like, and has a laser beam L for exposing the master disk.
Inject 0. The optical modulator 16A is an AOD (Accost Optic Deflector) composed of an electroacoustic optical element or the like, changes the emission direction of the laser beam L0 according to the modulation signal Vm, and outputs the laser beam L1. The laser beam L1 having the light traveling direction modulated in this manner.
Is input to the optical modulator 16B. The optical modulator 16B is
AOM (AccostOptic) composed of electroacoustic optical elements
Modulator), and the optical modulator 1 according to the modulation signal SB.
The light amount passing through 6B is controlled and output as laser light L2 whose light amount changes. Therefore, the traveling direction of the laser beam L2 is modulated by the modulation signal Vm, and the intensity thereof is changed according to the modulation signal Vp, so that the laser beam L2 is a light beam including both signal components of the modulation signals Vm and Vp at the same time.

The laser beam L2 thus obtained is
The optical path is bent by a mirror (not shown) and travels toward the disk master 17, and is further focused on the disk master 17 by an objective lens (not shown). These mirrors and objective lenses are synchronized with the rotation of the disk master 17 by a thread mechanism (not shown).
7, the exposure position by the laser beam L2 is sequentially displaced toward the outer periphery of the master disk 17.

Thus, in the optical disk apparatus 1, a spiral track is formed by moving the mirror and the objective lens while the master disk 17 is driven to rotate, and two signals of the modulation signal Vm and the modulation signal Vp are formed on the track. Exposure corresponding to. By performing recording after the laser light L2 has passed through the objective lens, a change in the traveling direction of the laser light L2 is recorded as a positional change of a spot focused on the master disk 17. The change in the intensity of the laser beam L2 is recorded as a change in the width of a groove (groove) recorded on the master disk 17. As described above, in this embodiment, information based on the two modulation signals Vm and Vp is multiplex-recorded on the same groove as a change in position in the track direction and a change in groove width.

Error correction code generation circuit (ECC) 11A
Is the digital data SA output from the information source 10A.
Then, after adding an error correction code, the signal is interleaved and output as 8-bit digital signals b0, b1,... B7. Similarly, an error correction code generation circuit (ECC) 11B
Is the digital data SB output from the information source 10B.
Then, after adding an error correction code, the signal is interleaved and output as an 8-bit digital signal b8, b9,... B15. In this way, by adding an error correction code to the two information sources to be superimposed and recorded, correct information can be read even if there is a defect on the disk.

The timing generator (TG) 12
Various time reference signals for controlling the timing of the entire optical disc recording apparatus 1 are generated and supplied to each section of the apparatus. Since it is not realistic to show all of these, only two signals, the BCLK signal and the SLCT signal, are shown in FIG. The BCLK signal is output from the ECC circuit 11A.
8 bit digital signal at a predetermined interval from
This is a clock signal that changes from logic 0 to 1 each time b0, b1,... b7 and b8, b9,. By knowing the change of the BCLK signal, the modulation circuits 4A and 4B transmit the 8-bit digital signals b0, b1,... B7 and b8, b9,.
Is updated.

Further, the SLCT signal is a signal which changes from logic 0 to 1 every time data for a predetermined time is recorded on the master disk 17. The selection of the analog switch 14 is switched according to the change of the SLCT signal, and the synchronization pattern obtained from the synchronization pattern generation circuit 13 is inserted. By inserting the synchronization pattern in this way, it is possible to obtain the synchronization of the reproduced signal from the generated disc by an easy method.

The modulation circuit 4A outputs the digital signals b0, b1,
... A modulated signal Vm is created in accordance with b7 and the BCLK signal.
As will be described later, the modulation signal V
m is an analog waveform. The modulation circuit 4B has almost the same configuration as that of the modulation circuit 4A.
.. b15 and the BCLK signal to generate a modulation signal Vn. Further, the modulation signal Vn created in this manner also has an analog waveform. The modulation signal Vn is corrected by the characteristic correction circuit 5 for signal characteristics specific to the push-pull signal in the tangential direction.
After the nonlinear characteristics of the modulated signal V
Output as o. Modulated signal Vo corrected
After passing through the analog switch 14
B is recorded on the master disk 17.

The synchronization pattern generation circuit 13 generates a synchronization pattern necessary for reproduction, address information, servo information necessary for access, and the like.

The laser modulation signal Vp obtained from the output of the analog switch 14 in this manner is
The output power of the laser beam L1 obtained from the optical modulator 16A is modulated and exposure is performed on the optical disk master 17, so that information from both the information source 10A and the information source 10B are simultaneously written on the optical disk master 17. It is superimposed and recorded.

FIG. 2 is a block diagram showing a configuration of the modulation circuit 4A. In the figure, digital signals b0, b1,..., B7 input to a modulation circuit 4A are input to eight level conversion circuits 49A to 49H, and have eight polarities whose amplitudes take either +1 or -1. Are converted to signals p0, p1, ... p7. These eight level conversion circuits 49A to 49H are:
Each is composed of a D flip-flop, an adder circuit and an amplitude adjustment circuit, and their configurations are all the same. Here, the configuration of the level conversion circuit 49A is shown in FIG. 3 as an example.

In FIG. 3, the input digital signal
The output of b0 is first latched by the D flip-flop 490 at the transition point of the BCLK signal from the timing generator 12. Therefore, the output of the D flip-flop 490 is configured to be held at a constant value until a new digital signal b0 is obtained. The D flip-flop 490 normally has a TTL (Transis
The output Vs is a digital signal having a voltage of about 0 V (volts) or +4 V because it is constituted by a circuit called tor transistor logic. Adder 4
In 91, the output Vs of the D flip-flop 490 and the output of the fixed voltage generator 492 are added, and the result is output to the amplitude adjustment circuit 493. Fixed voltage generator 49
2 is always -2 V, so the adder 491
Is + 2V when Vs is + 4V.
When Vs is 0 V, a voltage of −2 V is added to the adder 49.
1 is obtained.

In the amplitude adjustment circuit 493, 0.5
Therefore, the polarity signal p0, which is the output of this circuit, becomes -1 V when Vs is 0 V (when b0 is logic 0), and Vs is +4 V (where b0 is logic 1). ), The output is + 1V. In this way, a positive or negative 1 V polarity signal p0 is obtained at the output of the level conversion circuit 49A. Level conversion circuit 49A
The same conversion is performed on all of the eight input digital signals b0, b1,... B7 of .about.49H to obtain eight polarity signals p0, p1,.

In FIG. 2, 41A to 41D are transmitters for transmitting four types of sine waves. In this embodiment, the transmission frequency f2 of the transmitter 41B is twice as large as the transmission frequency f1 of the transmitter 41A. Further, the transmitter 41
The transmission frequency f3 of C is three times f1. The transmission frequency f4 of the transmitter 41D is four times as high as f1. Outputs of these four transmitters 41A to 41D are respectively + 45 ° phase shift circuits 42A, 42B and 42.
C, 42D, and -45 ° phase shift circuits 43A, 43
B, 43C and 43D.

The output of the transmitter 41A is connected to a + 45 ° phase shift circuit 42A and a −45 ° phase shift circuit 43A. Among them, the configuration of the + 45 ° phase shift circuit 42A is as shown in FIG. 4A. In this figure, the input signal Vin is composed of a resistor R42A and a capacitor C
Pass through a low pass filter according to 42A. The values of the resistor R42A and the capacitor C42A are
The transmission frequency f1 of 1A is determined so as to satisfy Expression 1.

[0043]

F1 = 1 ÷ (2π · R42A · C42A) By passing through such a low-pass filter,
The signal of the frequency f1 is subjected to a 45 ° phase shift. However, at the same time as the phase shift, the amplitude also drops by about 3 dB. Therefore, in the circuit shown in FIG. 4A, the output from the low-pass filter is amplified by 3 dB by the amplifier circuit 420A, and the signal amplitude by this circuit is not changed.

The configuration of the -45 ° phase shift circuit 43A is as shown in FIG. 4B. In this figure, an input signal Vin is composed of a resistor R43A and a capacitor C43.
Pass through a high pass filter according to 43A. Here, the values of the resistor R43A and the capacitor C43A are
Equation (2) is determined for the transmission frequency f1 of A.

[0045]

F1 = 1 ÷ (2π · R43A · C43A) By passing through such a high-pass filter,
The signal of the frequency f1 is subjected to a phase shift of −45 °.
However, at the same time as the phase shift, the amplitude also drops by about 3 dB. For this reason, in the circuit shown in FIG. 4B, the output from the low-pass filter is amplified by 3 dB by the amplifier circuit 430A, and the signal amplitude by this circuit is not changed.

As a result, the + 45 ° phase shift circuit 42
Carrier signal S1 obtained from the output of A, and -45 °
The carrier signal S2 obtained from the output of the phase shift circuit 43A is a signal that can be expressed by Expression 3 when the transmission frequency of the transmitter 41A is f1. (Here, A represents a constant, and t represents time.)

[0047]

S1 = A · sin (2π · f1 · t) S2 = A · cos (2π · f1 · t)

Similarly, the + 45 ° phase shift circuit 42
The B and −45 ° phase shift circuit 43B is also configured. Accordingly, the carrier signal S3 obtained from the output of the + 45 ° phase shift circuit 42B and the carrier signal S4 obtained from the output of the −45 ° phase shift circuit 43B are expressed by the following equation (4).

[0049]

S3 = A · sin (2π · 2 · f1 · t) S4 = A · cos (2π · 2 · f1 · t)

Similarly, the + 45 ° phase shift circuit 42
Carrier signal S5 obtained from the output of C, and -45 °
The carrier signal S6 obtained from the output of the phase shift circuit 43C is represented by Expression 5.

[0051]

S5 = A · sin (2π · 3 · f1 · t) S6 = A · cos (2π · 3 · f1 · t)

Similarly, the + 45 ° phase shift circuit 42
Carrier signal S7 obtained from the output of D, and -45 °
The carrier signal S8 obtained from the output of the phase shift circuit 43D is represented by Expression 6.

[0053]

S7 = A · sin (2π · 4 · f1 · t) S8 = A · cos (2π · 4 · f1 · t)

As described above, the + 45 ° phase shift circuits 42A, 42B, 42C, 42D, and -45 °
At the outputs of the phase shift circuits 43A, 43B, 43C, 43D, eight types of carrier signals S1 to S8 having different frequencies or phases are obtained. Each of these eight carrier signals has a frequency that is an integral multiple of the fundamental frequency f1. When these eight types of carrier signals are compared with each other at the same frequency, the phase shift is 90 degrees. Therefore, these eight types of carrier signals S1 to S8 are orthogonal to each other.

The eight types of carrier signals S1 to S8
Is input to the eight multiplication circuits 44A to 44H. Each of the eight multiplication circuits 44A to 44H has a carrier signal S
The calculation of the product of 1 to S8 and the eight polarity signals p0, p1,... P7 is performed. These results indicate that the eight amplifier circuits 45A to 45H
Are respectively amplified by K1 to K8 times, and the carrier signals V1 to V8 of Expression 7 are generated. That is, it is as follows.

[0056]

V1 = + K1 · A · sin (2π · f1 · t) . .
When b0 is logic 1. V1 = −K1 · A · sin (2π · f1 · t). . .
When b0 is logic 0. V2 = + K2 · A · cos (2π · f1 · t). . .
When b1 is logic 1. V2 = −K2 · A · cos (2π · f1 · t). . .
When b1 is logic 0. V3 = + K3 · A · sin (2π · 2 · f1 · t)
. . . When b2 is logic 1. V3 = -K3 · A · sin (2π · 2 · f1 · t)
. . . When b2 is logic 0. V4 = + K4 · A · cos (2π · 2 · f1 · t)
. . . When b3 is logic 1. V4 = -K4 · A · cos (2π · 2 · f1 · t)
. . . When b3 is logic 0. . . . V8 = + K8 · A · cos (2π · 4 · f1 · t)
. . . When b7 is logic 1. V8 = -K8 · A · cos (2π · 4 · f1 · t)
. . . When b7 is logic 0.

As described above, the 8-bit digital signal b
0, b1,..., B7, the eight different carrier signals S1 to S8 are modulated and the carrier signals V1 to V8 are modulated.
Is obtained. The eight types of carrier signals S1 to S8 used here are orthogonal to each other.

When reproducing an optical disk, not limited to the present invention, a phenomenon occurs that the amplitude of a reproduced signal differs depending on frequency components because the size of a light spot used for reproduction is finite. In an optical system generally used, the amplitude of a reproduced signal decreases as the frequency increases. In order to reduce the influence of such frequency characteristics, in this case, the values of the amplification factors K1 to K8 amplified in the eight amplifier circuits 45A to 45H are set to be different according to the frequencies of the input carrier signals S1 to S8. Have been. That is, each amplification factor is set so as to be expressed by Expression 8.

[0059]

## EQU8 ## K1, K2 <K3, K4 <K5, K6
<K7, K8

As described above, since the amplification factor differs depending on the frequency, the influence of the frequency characteristic upon reproducing the completed disc is reduced, and a substantially uniform signal amplitude can be obtained.

The eight carrier signals V1 to V8 obtained as described above are all added by the adder 46, and an added signal Vk is obtained. The added signal Vk obtained in this way is a signal whose amplitude changes to both plus and minus, usually around 0V. However, some optical modulators used in cutting machines do not accept negative voltages. In this figure, the adder 47 adds the fixed voltage Vb from the fixed voltage generator 48 to the addition signal Vk to prepare for the modulation signal Vk.
m.

The modulation signal Vm obtained from the modulation circuit 4A in this manner is replaced as a change in the direction of the laser beam L1 by the optical modulator 16A in FIG.

On the other hand, the information SB output from the information source 10B is also added with an error correction code by the error correction code generation circuit 11B, and after being subjected to interleaving processing, an 8-bit digital signal b8, b9,. Output as .b15. The 8-bit digital signals b8, b9, ...
A modulation signal Vn is created for b15 by the modulation circuit 4B. The configuration of the modulation circuit 4B is basically the same as that of the modulation circuit 4B.
Since it is equivalent to A, the description here is omitted.

The modulation signal Vn obtained from the modulation circuit 4 in this manner is sent to the characteristic correction circuit 5 in FIG. 1, and the information recorded as the change in the groove width is converted into a PP (push-pull) in the tangential direction. Is converted so that it can be detected as In the characteristic correction circuit 5,
Further, characteristics such as non-linear characteristics peculiar to the optical modulator 16B are corrected.

The configuration of the characteristic correction circuit 5 is as shown in FIG. The input modulation signal Vn is supplied to an oscillation circuit (O
Each time the clock signal ADCK is output from the SC) 55 at a constant period, the clock signal ADCK is converted into a digital value by the AD converter 51. The output of the AD converter 51 is input to the integration circuit 52, and the value obtained for each clock signal ADCK is integrated. As described later, it is assumed that the output signal Vo of the characteristic correction circuit 5 is detected as a PP (push-pull) signal in the tangential direction after being recorded as a change in groove width. When the detection is made with the PP signal in this manner, the differentiated waveform of the recorded signal is reproduced. Therefore, by performing integration in advance in the characteristic correction circuit 5, a signal having a correct waveform can be expected when PP detection in the tangential direction is performed.

The output signal of the integration circuit 52 is input as an address of a ROM (Read Only Memory) 53. In the ROM 53, characteristics for correcting expected non-linear characteristics such as the characteristics of the optical modulator 16B are recorded corresponding to each input address. In this way, a value according to the previously recorded correction characteristic is read out,
The original analog voltage is converted by the converter 54 and output as a modulation signal Vo. The oscillation circuit 55 oscillates at a sufficiently high predetermined frequency, and
1. A clock signal ADCK for driving the integration circuit 52 and the DA converter 54 is output.

When an example of such an input-output characteristic of the ROM 53 is shown, for example, a curve as shown in FIG. 6 is plotted. A sequence of numerical values according to the characteristics shown in FIG.

The modulation signal Vo thus created is input to the analog switch 14, and after a synchronization pattern is periodically inserted, is supplied to the optical modulator 16B as a signal Vp in FIG. The laser beam L
1 is intensity modulated. The laser beam L1 whose light direction has been changed by the light modulator 16A in this manner is further intensity-modulated by the light modulator 16B and then irradiated onto the master disc 17, whereby information from the information source 10A is transmitted. Information SB recorded as a change in the position of the groove on the disc master 17 and further sent from the information source 10B
Is recorded by exposure as a change in groove width.

On the disk master 17 on which the exposure recording has been performed in this manner, the portion recorded by the development appears as an uneven pattern. Further, a mother disk is prepared by electroforming. A stamper is created using this mother disk. By repeating injection molding on the basis of the stamper thus completed, it is possible to obtain the optical disk 2 copied in large quantities.

FIG. 7 shows the state of the optical disk 2 thus completed. When a part of the optical disk 2 is enlarged by, for example, a microscope, a recording signal as shown in the lower part of FIG. Here, the recording signal is basically a groove (groove) 70, and its width changes according to the modulation signal Vo. The center position of the groove 70 is changed by the modulation signal Vm. Further, although not shown in FIG. 7, a synchronization signal from the synchronization pattern generation circuit 13 is periodically embedded as a pit. Further, in a portion where the width of the groove 70 is narrow, the groove 70 may be partially interrupted to form a land.

Next, referring to FIG. 8, an optical disc reproducing apparatus 3 for reproducing the optical disc 2 on which digital information from the information sources 10A and 10B are recorded as groove widths and position shifts by the method described above. explain. The optical disk 2 is rotated by a spindle motor 31. The spindle motor 31 and the optical pickup 32 are controlled to perform predetermined operations by a servo circuit (not shown). 4 inside the optical pickup 32
Outputs from the split detectors 321 (A, B, C, D) are amplified to a sufficient amplitude by an amplifier circuit (not shown) provided inside the optical pickup 32, and then input to a matrix operation circuit (MA) 33.

In the matrix operation circuit 33, four outputs (A, B, C, D) from the quadrant detector 321
The following equation 9 is calculated for the output.

[0073]

RF signal = A + B + C + D PP signal = A + B−C−D TPP signal = A−B−C + D FE signal = A−B + C−D

In the equation (9), the FE signal is a focus error signal, which is used for focusing the objective lens provided inside the pickup 32. Accordingly, the FE signal is supplied to a servo circuit (not shown), and control is performed so that the light beam from the objective lens always focuses on the optical disk 2. Since the RF signal holds information recorded as pits, it is supplied to the PLL circuit 34. TP
The P signal is a push-pull signal in the tangential direction, and holds information recorded as the width of the groove.
Therefore, the TPP signal is sent to the decoding circuit 6A, and the information source 1
The information from 0A is decoded. The PP signal is a push-pull signal in the radial direction, and holds information recorded as a shift in groove position. Therefore, the PP signal is sent to the decoding circuit 6B, and the information from the information source 10B is decoded.

As an example, FIG. 11 shows an RF signal, a PP signal, and a TPP signal obtained by calculating a reproduction signal by computer simulation when a pattern as shown in FIG. 7 is recorded, for example. In the pattern shown in FIG. 7, as the simplest example, a sine wave of the fundamental frequency is recorded as a change in the position of the groove 70. Further, as a change in the width of the groove 70, a signal having a frequency that is twice the fundamental frequency described above is recorded. When such a signal is reproduced, the RF signal 11 as shown by the uppermost curve in FIG.
0 is obtained. Although this curve is modulated according to the change in the width of the groove 70, it is presumed that the curve is greatly affected by dust and dirt on the disk surface because the distortion is large and the DC component is included. On the contrary,
When a tangential push-pull (PP) is calculated, a clear signal with little distortion can be obtained as shown as a TPP signal 112 at the bottom of the figure. In addition, since the DC component is eliminated, it is expected that the disk surface is hardly affected by dust and dirt. Similarly, the push-pull signal in the radial direction is P
A beautiful signal as shown as the P signal 111 is obtained. Since this signal also has no DC component, it is less susceptible to dust and dirt. Further, according to the result of this figure, the information recorded as the change in the groove width (TPP signal 112) and the information recorded as the position shift of the groove (PP signal 111) are independent signals as signals of different frequencies. It can also be seen that it has been detected. As described above, since two types of signals can be independently recorded and reproduced, this system can realize a higher recording density than the conventional recording system.

The PLL circuit 34 converts the synchronization signals periodically embedded in the RF signal into channel clocks CK1 to CK1.
CK4 and a timing pulse BCLK are generated. The channel clock CK1 generated here has the same frequency as the carrier signal S1 or S2 used at the time of recording. Similarly, the channel clock CK2 includes the carrier signal S3 or S4 and the channel clock CK3.
Is carrier signal S5 or S6, channel clock C
K4 has the same frequency as the carrier signal S7 or S8. The timing pulse BCLK is a digital signal b0, b1,... B7 recorded on the optical disc 2.
Is a signal representing the delimitation of. That is, the digital signal b0, b recorded on the signal obtained from the optical disc 2
The signal is such that a pulse is generated at the switching portion of 1,... B7.

The decoding circuit 6A decodes information recorded based on the TPP signal, the channel clocks CK1 to CK4 from the PLL circuit 34, and the timing pulse BCLK, and supplies the information to the ECC circuit 36A. ECC circuit 36A
Is the ECC (Error
Based on the Correcting Code, errors in the signal output from the decoding circuit 6A are corrected. Such an error is caused, for example, by a defect on the optical disc 2 or the like.

In the decoding circuit 6B, the PP signal, PL
The information recorded based on the channel clocks CK1 to CK4 from the L circuit 34 and the timing pulse BCLK is decoded and supplied to the ECC circuit 36B. The ECC circuit 36B includes an ECC circuit added in encoding at the time of recording.
(Error Correcting Code), the decoding circuit 6B
To correct errors in the signal output from. Such an error is caused, for example, by a defect on the optical disc 2 or the like.

The output A signal obtained from the output of the ECC circuit 36A is equal to the information output from the information source 10A. The output B signal obtained from the output of the ECC circuit 36B is equal to the information output from the information source 10B. Therefore, for example, when the present reproducing apparatus is applied to the same application as a compact disk player, the ECC circuit 36A or the EC
By connecting a DA converter and a speaker to one of the outputs of the C circuit 36B, a music signal is reproduced from the speaker. Of course, the information recorded by the information source 10A and the information recorded by the information source 10B may be different from each other. For example, by switching the connection destination for connecting the DA converter and the speaker to the ECC circuit 36A and the ECC circuit 36B, for example, It becomes possible to enjoy various kinds of music.

The decoding circuits 6A and 6B have the same internal configuration. Therefore, only the internal configuration of the decoding circuit 6A will be described with reference to FIG.
B is omitted. In the figure, the channel clock CK1 is a signal having the same frequency (f1) as the carrier signals S1 and S2, but is a signal generated by the PLL circuit, and therefore includes a digital signal including a number of harmonics in addition to the frequency f1 component. Signal. Therefore, the channel clock CK1 is supplied to the bandpass filter 61A.
And only the frequency components equal to the carrier signal S1, that is, the frequency components before and after the frequency f1, are extracted, and unnecessary harmonic components are removed.

The signal composed of only the frequency component f1 obtained in this way is supplied to the + 45 ° phase shift circuit 62A and the −45 ° phase shift circuit 63A, and the phase is changed by ± 45 °. As a result, +45
The output of the phase shift circuit 62A is sin (2π · f
1 · t), and a signal of cos (2π · f1 · t) is obtained at the output of the −45 ° phase shift circuit 63A.

Similarly, the channel clock CK2
Is a signal having the same frequency (f2) as the carrier signals S3 and S4, but is a signal including a large number of harmonics because it is a signal generated by the PLL circuit. Therefore, the channel clock CK2 is supplied to the band-pass filter 61B, and only the frequency components before and after the frequency f2 are extracted, and unnecessary harmonic components are removed.

The signal consisting of only the frequency component f2 obtained in this manner is supplied to the + 45 ° phase shift circuit 62B and the −45 ° phase shift circuit 63B, and the phases thereof are changed by ± 45 °. As a result, +45
The output of the phase shift circuit 62B is sin (2π · 2
F1 · t), and the output of the −45 ° phase shift circuit 63B has cos (2π · 2 · f1 · t).
Is obtained.

Similarly, the channel clock CK3
Is a signal having the same frequency (f3) as the carrier signals S5 and S6, but is a signal generated by the PLL circuit, and thus contains many harmonics. Therefore, the channel clock CK3 is supplied to the band-pass filter 61C, and only the frequency components before and after the frequency f3 are extracted, and unnecessary harmonic components are removed.

The signal consisting of only the frequency component f3 obtained in this way is supplied to the + 45 ° phase shift circuit 62C and the −45 ° phase shift circuit 63C, and the phase thereof is changed by ± 45 °. As a result, +45
° The output of the phase shift circuit 62C is sin (2π · 3
F1 · t), and the output of the −45 ° phase shift circuit 63C has cos (2π · 3 · f1 · t).
Is obtained.

Further, the channel clock CK4 is a signal having the same frequency (f4) as the carrier signals S7 and S8, but is a signal generated by the PLL circuit, and thus contains many harmonics. Therefore, the channel clock CK4 is supplied to the band pass filter 61D,
Only the frequency components before and after the frequency f4 are extracted, and unnecessary harmonic components are removed.

The signal consisting of only the frequency component f4 obtained in this way is supplied to the + 45 ° phase shift circuit 62D and the −45 ° phase shift circuit 63D, and the phases thereof are changed by ± 45 °. As a result, +45
The output of the phase shift circuit 62D is sin (2π · 4
F1 · t), and the output of the −45 ° phase shift circuit 63D has cos (2π · 4 · f1 · t).
Is obtained.

The + 45 ° phase shift circuits 62A to 62A
2D and -45 ° phase shift circuits 63A to 63D
Can be realized by the method described with reference to FIG. 4A or FIG. 4B.

In this manner, the + 45 ° phase shift circuit 6
2A to 62D, and -45 ° phase shift circuit 63A to
The carrier signal obtained from 63D is connected to analog multiplying circuits 66A to 66H, and multiplied with the RF signal obtained from each pickup. The eight types of carrier signals S1 to S8 used for recording are orthogonal to each other. Therefore, a signal equivalent to the carrier signals S1 to S8 is created again by the playback player in this manner,
By multiplying, the original signal can be reproduced again.

The outputs of the eight analog multiplication circuits 66A to 66H are connected to integration circuits 64A to 64H. Since the internal configuration of each of the integrating circuits 64A to 64H is the same, FIG. 10 shows the inside of the integrating circuit 64A. As shown in FIG. 10, the input signal is a resistor R
The integration is performed by an integration circuit including the capacitor 64A and the capacitor C64A. However, prior to starting the integration, the condenser C64A is cleared.
That is, the timing signal B indicating the break of the recorded signal
CLK, the analog switch 641A is momentarily turned on immediately before starting the integration, and the capacitor C64A is turned on.
It is made clear by discharging the electrification that had been integrated until then.

In the integrating circuit 64A, the capacitor C
The integrated value appearing as the voltage of 64A is output after being amplified by the buffer amplifier 642A.

As described above, the integration circuits 64A to 64A
64H integrates the outputs of the eight analog multiplication circuits 66A to 66H, respectively. Also, before new data is read from the disc, BC
Each integrated value is cleared by the LK signal.

Outputs from integrating circuits 64A to 64H (FIG. 9)
X1 to X8 are input to the analog comparators 65A to 65H. The analog comparators 64A to 65H compare the input voltages X1 to X8 with a reference voltage (usually 0 volt), and when the voltage is higher than the reference voltage, set logic 1 and the input voltage is lower than the reference voltage. For example, a logic 0 is output. By comparing with the reference voltage in this way, even if there is some noise, it is possible to decode the digital signal b0, b1,... B7 recorded correctly.

Thus, the analog comparator 65
The signals obtained from A to 65H are input to D flip-flops 66A to 66H, respectively, and are latched at the transition points of BCLK. That is, the integration circuits 64A to 64H
Is completed, the outputs of the analog comparators 65A to 65H are latched and held as the outputs of the D flip-flops 66A to 66H. These output signals are the same as those obtained as digital signals b0, b1,... B7 during recording, except for the influence of defects and the like.

In the embodiment described above, the portion of the decoding circuit 6A is realized by hardware as shown in FIG. However, recently, elements called a DSP (Digital Signal Processor) have been remarkably advanced, and this part can be realized by software.

In the above description of the embodiment, the configuration in which the integrating circuit is provided inside the characteristic correction circuit 5 for the purpose of correcting the PP (push-pull) characteristic in the tangential direction has been described. However, the present invention is not limited to this. For example, the correction of the PP characteristic in the tangential direction
Of course, it can be placed inside the playback device.

In the above-described embodiment, the digital signals b0, b1,..., B15 are all described as 1-bit information. However, the present invention is not limited to this. For example, 2-bit information is used as b0. It is also possible to multi-modulate the quadrature signal. In this case, it is possible to further improve the recording density.

In the embodiment shown in FIG. 1, the optical modulator 16A first modulates the direction of the laser beam, and then the optical modulator 16B modulates the intensity of the laser beam. However, the present invention is not limited to this. For example, the positional relationship between the optical modulators 16A and 16B is exchanged, intensity modulation is performed first by the optical modulator 16B, and then the direction of the laser beam is modulated by the optical modulator 16A. Even if it is configured to do so, of course, it does not matter.

[0099]

According to the first aspect of the present invention, a first modulation signal and a second modulation signal are generated from digital information recorded on an optical disk, and the lateral position of a laser beam is displaced in accordance with the first modulation signal. An optical disk recording apparatus comprising: a laser beam position displacement device for causing a laser beam to move;
In this manner, the information by the lateral shift and the information by the intensity modulation (modulation of the width of the groove, which is equivalent to recording information without pits in the conventional method) are superimposed on the same groove. Since recording is possible, the optical disc recording apparatus according to the present invention can realize a recording density much higher than that of the conventional one.

In the invention described in claim 2 or later, sine waves and cosine waves having different frequencies are used as the first and second modulated signals in the invention described in claim 1 as a plurality of orthogonal signals. As a result, the information to be recorded is concentrated in a frequency region centered on the frequency of the sine wave or cosine wave used for recording. Therefore, it is possible to effectively use the frequency characteristic peculiar to the optical disc, and it is possible to realize a high recording density.

According to a fourteenth aspect of the present invention, there is provided a method for recording on an optical disk, wherein first and second recording signals are generated in accordance with information to be recorded, and the first and second recording signals are used to collect light on a disk-shaped recording medium. This is an optical disc recording method in which the position of the light beam is displaced laterally with respect to the track, and the intensity of the converged light beam on the disc-shaped recording medium is changed by a first recording signal. In this way,
Information by lateral displacement and information by intensity modulation (modulation of groove width, which is equivalent to recording information without pits in the conventional method) can be superimposed and recorded on the same groove Therefore, by using the optical disk recording method according to the present invention, it is possible to realize a recording density much higher than that of the conventional one.

The invention described in claim 15 or later is a recording system using sine waves and cosine waves having different frequencies as the first and second recording signals in the invention described in claim 14. As a result, the information to be recorded is concentrated in a frequency region centered on the frequency of the sine wave or cosine wave used for recording. Therefore, it is possible to effectively use the frequency characteristics peculiar to the optical disk, and it is possible to realize a higher recording density.

An eighteenth aspect of the present invention is an optical disc, wherein a first signal and a second signal superimposed on the same groove are recorded, and the first signal is recorded on a track of the groove. Recorded as a lateral displacement,
The second signal is recorded by changing the width or depth of the groove. That is, in the present invention, two types of information are recorded in one groove, namely, information recorded by shifting the position in the horizontal direction and information recorded by changing the width or depth of the groove, so that high recording as a whole is achieved. Density is achieved.

In the invention described in claim 19 and thereafter, sine waves and cosine waves having different frequencies are used as the first and second signals in the invention described in claim 18. As a result, the recorded information is concentrated in a frequency region centered on the frequency of the sine wave or the cosine wave. Therefore, it is possible to effectively use the frequency characteristic peculiar to the optical disk, and it is possible to realize an optical disk recorded at a high recording density.

According to a twenty-fourth aspect of the present invention, when reproducing an optical disk, a first detecting means for obtaining a first detection signal relating to a track displacement amount from a laser beam reflected by the optical disk and arrived at the detector. Signal processing means comprising: second detection means for obtaining a second detection signal related to the amount of change in track width or depth; and signal processing means for performing signal processing on the first and second detection signals. The digital information is decoded and output from the output of (i), so that information recorded as a positional shift in the horizontal direction of the track and information recorded as a change in the width or depth of the track are separated. And can be detected. Therefore, the optical disk reproducing apparatus according to the twenty-fourth aspect of the present invention can reproduce a disk recorded at a higher recording density than before.

According to a thirty-first aspect of the present invention, when reproducing an optical disk, a first detection signal relating to a displacement of a track is obtained from a light beam reflected by the disk, and the width or depth of the track is obtained from a laser beam. To obtain a second detection signal related to the amount of change. Further, there is provided an optical disc reproducing method for outputting digital information recorded by subjecting the first and second detection signals thus obtained to signal processing. Therefore, in the present optical disk reproducing method, it is possible to separately detect information recorded as a change in position of a track in the lateral direction and information recorded as a change in the width or depth of a track. Therefore, the optical disk reproducing apparatus according to the thirty-first aspect can reproduce a disk recorded at a higher recording density than before.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a configuration of a modulation circuit 4A in the optical disk device of FIG.

FIG. 3 is a block diagram illustrating a configuration of a level conversion circuit in the modulation circuit of FIG. 2;

FIG. 4 is a block diagram showing a phase shift circuit in the modulation circuit of FIG. 2;

FIG. 5 is a block diagram illustrating a configuration of a characteristic correction circuit in FIG. 1;

FIG. 6 is a diagram showing an example of input / output characteristics recorded in a ROM in the characteristic correction circuit in FIG. 6;

FIG. 7 schematically shows an optical disk according to an embodiment of the present invention and a partial enlargement thereof.

FIG. 8 is a block diagram showing an overall configuration of an optical disc reproducing apparatus according to the present invention.

9 is a block diagram illustrating a configuration of a decoding circuit in FIG.

FIG. 10 is a block diagram illustrating a configuration of an integration circuit in FIG. 9;

FIG. 11 is a waveform chart in a case where the principle of a reproduced signal in the optical disc of the present invention is confirmed by computer simulation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk recording device, 2 ... Compact disk, 2 ... Optical disk reproducing device, 4A, 4B ... Modulation circuit, 5 ... Characteristic correction circuit, 6A, 6B ... Decoding circuit, 1
5. Laser, 16A, 16B ... Optical modulator, 17 ...
Master disk, 18 ... Spindle motor, 19 ... Spindle servo circuit

Claims (32)

[Claims] 1. An optical disk recording apparatus for recording digital information inputted by irradiating a laser beam condensed by optical means, wherein a first modulation signal for generating a first modulation signal which changes in accordance with the digital information is provided. Means, a second modulation means for creating a second modulation signal that changes according to the digital information, a laser light position displacement means for displacing the position of the laser beam on the optical disk according to the first modulation signal, An optical disk recording apparatus comprising: a laser intensity modulation unit that modulates the intensity of the laser beam according to the second modulation signal. 2. The optical disk recording apparatus according to claim 1, wherein the first modulating means includes: a plurality of orthogonal signal generating means for generating orthogonal signals orthogonal to each other; An optical disc recording apparatus, comprising: synthesized signal generating means for generating a synthesized signal by performing an operation. 3. The optical disk recording apparatus according to claim 2, wherein the plurality of orthogonal signals are a plurality of sine waves having different frequencies and a plurality of cosine waves having different frequencies. apparatus. 4. The optical disk recording device according to claim 3, wherein the frequency of the plurality of orthogonal signals is an integral multiple of a predetermined frequency. 5. The optical disk recording apparatus according to claim 4, wherein said second modulating means comprises: a plurality of orthogonal signal generating means for generating orthogonal signals orthogonal to each other; An optical disc recording apparatus, comprising: synthesized signal generating means for performing an operation to generate a synthesized signal. 6. The optical disc recording apparatus according to claim 5, wherein the plurality of orthogonal signals are a plurality of sine waves having different frequencies from each other and a plurality of cosine waves having different frequencies from each other. apparatus. 7. The optical disk recording apparatus according to claim 6, wherein the frequency of the plurality of orthogonal signals is an integral multiple of a predetermined frequency. 8. The optical disc recording apparatus according to claim 2, wherein the composite signal generating means calculates a product of a predetermined bit of the digital information and a predetermined signal of the plurality of orthogonal signals. An optical disc recording apparatus, comprising: a product calculating means for calculating the sum of outputs of the plurality of product calculating means. 9. The optical disc recording apparatus according to claim 5, wherein the composite signal generating means calculates a product of a predetermined bit of the digital information and a predetermined signal of the plurality of orthogonal signals. An optical disc recording apparatus, comprising: a product calculating means for calculating the sum of outputs of the plurality of product calculating means. 10. The optical disk recording apparatus according to claim 8, wherein said composite signal generation means includes a synchronization signal generation means for generating a synchronization signal. 11. The optical disk recording apparatus according to claim 9, wherein said composite signal generating means includes a synchronizing signal generating means for generating a synchronizing signal. 12. The optical disk recording apparatus according to claim 1, wherein the laser light intensity modulation means is an intensity modulator for modulating the intensity of the laser light, and corrects a nonlinear characteristic of the intensity modulator. An optical disk recording device comprising means. 13. The optical disk recording apparatus according to claim 1, wherein the laser light intensity modulation means is an intensity modulator for modulating the intensity of the laser light, and integrates a signal input to the laser light intensity modulation means. An optical disc recording apparatus, comprising an integrating means for performing an operation. 14. A method for recording an optical disk in which desired input data is recorded on the disk-shaped recording medium by irradiating a focused light beam on the disk-shaped recording medium, wherein a first and a second are obtained from the input data. The position of the condensed light beam on the disk-shaped recording medium is displaced in a lateral direction with respect to a track by the first recording signal, and the first recording signal An optical disk recording method, comprising changing the intensity of the condensed light beam on a disk-shaped recording medium. 15. The optical disc recording method according to claim 14, wherein the first recording signal generates a plurality of sets of orthogonal reference signals, generates a plurality of data strings from the input data, and An optical disc recording method, comprising: modulating a plurality of sets of modulated signals by respectively modulating the corresponding reference signals with a column; and adding the modulated signals to generate the first recording signal. 16. The optical disk recording method according to claim 15, wherein the second recording signal generates a plurality of sets of orthogonal reference signals, generates a plurality of data strings from the input data, and An optical disc recording method, comprising: modulating each of the reference signals corresponding to a column to generate a plurality of sets of modulation signals; and adding the modulation signals to generate the second recording signal. 17. The optical disk recording method according to claim 16, wherein the plurality of orthogonal reference signals include a plurality of sine wave signals and a plurality of cosine wave signals, and the plurality of sine wave signals and the cosine wave signals. Wherein the frequency is an integral multiple of a predetermined frequency. 18. A method for reading digital information recorded on an optical disk medium by irradiating the optical disk medium with a laser beam and converting the laser beam reflected by a substantially focal position on the optical disk medium into an electric signal. An optical disc medium, wherein the digital information is recorded by a first signal and a second signal which are superimposed and recorded on the same groove, and wherein the first signal is recorded on a track of the groove. An optical disk medium characterized in that the second signal is recorded as a lateral displacement, and the second signal is recorded as the width or depth of the groove changes. 19. The optical disk medium according to claim 18, wherein the first signal is recorded on the medium so as to be a sum of a plurality of orthogonal signals orthogonal to each other. 20. The optical disk medium according to claim 18, wherein the second signal is recorded on the medium so as to be a sum of a plurality of orthogonal signals orthogonal to each other. 21. The optical disc medium according to claim 19, wherein the plurality of orthogonal reference signals are composed of a plurality of sine wave signals and a plurality of cosine wave signals. An optical disk medium, wherein the frequency is an integer multiple of a predetermined frequency. 22. The optical disc medium according to claim 20, wherein the plurality of orthogonal reference signals are constituted by a plurality of sine wave signals and a plurality of cosine wave signals. An optical disk medium, wherein the frequency is an integer multiple of a predetermined frequency. 23. The optical disk medium according to claim 18, wherein the second signal is reflected forward of the laser beam reflected by the optical disk medium in a direction in which the groove is formed. The difference between the intensity of the light beam and the intensity of the light beam reflected in the direction behind the groove is recorded so as to be the sum of a plurality of orthogonal signals that are substantially orthogonal to each other. An optical disc medium characterized by the following. 24. An optical disk reproducing apparatus for reading out digital information recorded on a medium in which information is recorded in advance on a spirally formed track by condensing and irradiating a laser beam with an optical means. An apparatus comprising: first detection means for obtaining a first detection signal related to a displacement amount of the track from the laser beam reflected by the medium and passing through the optical means again; and Second detection means for obtaining a second detection signal related to a change in the width or depth of the track from the laser beam having passed through the means again; and performing signal processing on the first and second detection signals. An optical disc reproducing apparatus comprising signal processing means, decoding and outputting the digital information from an output of the signal processing means. 25. The optical disc reproducing apparatus according to claim 24, wherein the first detecting means detects a light beam diffracted rightward with respect to the track in the laser beam; A second photoelectric detector for detecting light diffracted leftward with respect to the track in the laser beam; and a difference signal calculator for calculating a difference between the first and second photoelectric detectors. An optical disc reproducing apparatus characterized by the above-mentioned. 26. The optical disk reproducing apparatus according to claim 24, wherein the second detecting means detects third light of the laser beam diffracted forward with respect to the track; A fourth photoelectric detector for detecting light diffracted backward with respect to the track in the laser beam; and a difference signal calculator for calculating a difference between the third and fourth photoelectric detectors. An optical disc reproducing apparatus characterized by the above-mentioned. 27. The optical disk reproducing apparatus according to claim 26, wherein the signal processing unit includes: a quadrature signal generation unit that generates a plurality of orthogonal signals orthogonal to each other; a product of the quadrature signal and the first detection signal. A plurality of sum-of-products calculating means for performing a sum calculation, a plurality of sum-of-products calculating means for performing a sum-of-products operation of the orthogonal signal and the second detection signal, and digital information based on an output of the sum-of-products calculating means. An optical disc reproducing apparatus comprising: decoding means for decoding. 28. The optical disk reproducing apparatus according to claim 27, wherein said orthogonal signal generating means generates a sine wave or a cosine wave having a plurality of different frequencies. 29. The optical disc reproducing apparatus according to claim 28, wherein said orthogonal signal generating means and said product-sum operation means are FFT
(Fast Fourier Transform) means. 30. The optical disk reproducing apparatus according to claim 27, wherein said first decoding means is constituted by comparing means for decoding by comparing the output of said first product sum operation means with a predetermined slice level. Optical disk reproducing device. 31. A digital signal recorded on the medium by irradiating a laser beam that focuses on the medium and converting the laser beam reflected by the medium into an electric signal to obtain a reproduction signal. An optical disc reproducing method for reading out, obtaining a first detection signal related to a displacement amount of the track from the laser beam, and a second detection signal related to a variation amount of the width or depth of the track from the laser beam. Obtaining the digital information by subjecting the first and second detection signals to signal processing. 32. The optical disk reproducing method according to claim 31, wherein the signal processing includes: a quadrature signal generation step of generating a plurality of orthogonal signals orthogonal to each other; and a signal operation for calculating the orthogonal signal and the reproduction signal. And a decoding step of decoding the digital information based on an output of the signal operation means.