JPH08339544A - Optical disk, reproducing method and reproducing device - Google Patents

Abstract

PURPOSE: To provide an optical disk and its reproducing device with duplicate preventing function. CONSTITUTION: The optical disk is provided with an area 24 in which recorded with a regenerative signal is recorded so that its 0 and 1 are inverted when the signal is reproduced after the signal 26 of a fixed pattern. The reproducing device is additionally provided with a function for demodulating an RF signal into a digital signal and then inverting the signal when the signal 26 of the fixed pattern is detected and a function for stopping reproducing when the signal in the area 24 is not reproduced. Since only a regular signal can be recorded on a duplicated disk, when a part corresponding to the area 24 is to be inverted and reproduced, this is not reproduced as the regular signal, so that the reproduction is stopped to make the duplicated disk unreproducible, thus preventing illegal duplication.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium, and more particularly to an optical disc having an anti-duplication function, an optical disc reproducing method, an optical disc reproducing apparatus and the like.

[0002]

2. Description of the Related Art Optical discs are generally manufactured from a master disc to a master disc.
It is manufactured by making a mother and a stamper and replicating them in large quantities by injection molding. In some cases, the stamper is directly manufactured from the master.

In general, the master disc of an optical disk is formed by coating a glass substrate having a polished surface with a photoresist, exposing the photoresist with a laser beam whose intensity is modulated by an information signal to be recorded, and developing it to obtain an unevenness corresponding to its photosensitivity. It is manufactured by forming a rectangular signal or a groove or an uneven signal and a groove. Hereinafter, the uneven signal or groove or the uneven signal and groove will be collectively referred to as a signal pit.

FIG. 5 shows a block diagram of a master recording apparatus. A beam expander of a laser optical system for focus control and a laser optical system for recording is omitted. In FIG. 5, 1
Is a recording laser, 2 is a light modulator, 3 is a mirror, 4 is a lens actuator, 5 is a glass plate coated with a photoresist, 6 is a spindle motor, 7 is a signal source, and 8 is a recording equalizer.

The signal generated by the signal source 7 has its pulse width changed by a certain amount by the recording equalizer 8 and is input to the optical modulator 2 to intensity-modulate the laser light. The intensity-modulated laser light passes through the mirror 3 and exposes the photoresist on the glass plate 5 through the focus-controlled lens of the lens actuator 4.

A reproducing apparatus for an optical disk focuses a semiconductor laser on the signal surface of the optical disk, converts the intensity of light reflected from the signal surface into an electric signal by a photodiode or the like (this signal is called an RF signal), and shapes the waveform. Then, the original signal is reproduced by demodulating into a digital signal and performing digital signal processing.

FIG. 6 shows a block diagram of a conventional reproducing apparatus. In FIG. 6, 9 is an optical disk, 10 is an optical pickup, 11 is a spindle motor, 12 is an analog waveform shaping section, 13 is a digital demodulation section, 14 is a digital signal processing section, 15 is a control section, 16 is a focus servo section,
Reference numeral 17 is a tracking servo unit, and 18 is a rotation servo unit.

Optical discs such as compact discs,
Although the copy inhibition bit is defined, the playback device has not conventionally been provided with a copy protection function.

This is because a disc medium which can be written only once and which can be reproduced by an ordinary reproducing device has been put on the market. However, it is more expensive than the regular purchase of an optical disc.
This is because there is almost no need to take countermeasures against illegal duplication because the writing device is expensive and has not spread.

However, as games and the like are recorded on optical discs, the price of optical discs rises as the price of software rises, and on the other hand, the price of disc media that can be written only once and that can be reproduced by a normal reproducing apparatus decreases. By doing so, illegal copying becomes cheaper, and a copy protection function has been demanded.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical disc having a copy protection function and its reproducing device.

[0012]

The present invention has the above-mentioned objects.
The optical disc is provided with a recorded area so that 0 and 1 of the reproduction signal are inverted when the signal reproduction is performed after the signal of the constant pattern, and the reproduction device detects the signal of the constant pattern and then the RF signal. This is achieved by adding a function of inverting the signal after being demodulated into a digital signal and a function of stopping the subsequent reproduction if the signal in the region where the reproduction signal is inverted is not reproduced.

[0013]

The signal reproduced by the reproducing device and digitally demodulated from the recorded area so that 0 and 1 of the reproduced signal are inverted when the signal is reproduced is a normal signal,
When the demodulated signal is recorded on the recordable optical disc medium, the reproduced signal is recorded so as not to be inverted when reproduced.

Therefore, if the reproducing device demodulates the RF signal into a digital signal and then inverts the signal and reproduces the signal, the signal is not reproduced as a normal signal and the reproduction is stopped.
The duplicated disc cannot be played back, and illegal duplication can be prevented.

[0015]

The present invention relates to an optical disc having a copy protection function, a method for producing an optical disc master for producing such an optical disc, a reproducing method for reproducing such an optical disc, and a reproducing apparatus.

According to the present invention, a special master copy is created by mixing a special copy protection signal, which is different from usual, with a recording signal when a master disk of an optical disc such as a CD is created, and duplication is prevented. This special copy protect signal is C
Expressed as P signal.

An optical disc and its reproduction according to an embodiment of the present invention will be described below. FIG. 1 shows an embodiment of the optical disc of the present invention. In FIG. 1, 9 is an optical disk, 24 is an area recorded so that 0 and 1 of a reproduced signal are inverted when a signal is reproduced, 25 is a CP signal arrangement information signal, 26 is a CP signal preceding signal, 31 Is a program area, and 32 is a lead-in section.

In the optical disc of the present embodiment, the area 24 is recorded so that 0 and 1 of the reproduced signal are inverted when the signal is reproduced as the CP signal after the CP signal arrangement information signal 25 of the specific pattern. Is provided. Further, since the CP signal preceding signal 26 of a specific pattern is provided,
It serves as a preceding signal for clarifying that there is the inversion region 24 after that.

A plurality of CP signal advance signals 26 and a plurality of inversion regions 24 can be provided as shown in FIG.

FIG. 2 shows a block diagram of an embodiment of an optical disk reproducing apparatus of the present invention. In the reproducing apparatus of this embodiment, after the specific pattern signal, the CP signal arrangement information and the CP signal preceding signal 26 shown in FIG. 1 are detected by the CP signal arrangement information reproducing section, the RF signal is demodulated to a digital signal. It is provided with means for inverting the signal and means for deciding the reproduction disk to stop the reproduction or program operation unless the signal in the area where the reproduction signal is inverted is reproduced.

In FIG. 2, 9 is an optical disk, 10 is an optical pickup, 11 is a spindle motor, 12 is an analog waveform shaping section, 14 is a digital signal processing section, 16 is a focus servo section, 17 is a tracking servo section, and 1 is a tracking servo section.
Reference numeral 8 is a rotary servo unit, 19 is a digital demodulation unit capable of inverting a signal when demodulating an RF signal into a digital signal, 20
Is a control unit for controlling the digital demodulation unit 19 so as to invert the signal when the CP signal preceding signal of the specific pattern is detected.

The optical disc 9 has a spindle motor 11
Is rotated by. The semiconductor laser is focused on the signal surface of the optical disc 9 by the optical pickup 10, and the intensity of the reflected light from the signal surface is converted into an electric signal by a photodiode or the like to obtain an RF signal.

The optical pickup 10 is controlled by the focus servo section 16 so that the signal surface of the optical disk 9 is always focused, and the tracking servo section 17 is also provided.
The control is performed so that the focus of the semiconductor laser follows the signal track.

The RF signal is subjected to waveform shaping by the analog waveform shaping section 12, demodulated into a digital signal by the digital demodulation section 19, and digital signal processed by the digital signal processing section 14 to reproduce the original signal.

The control section 20 controls the movement of the entire reproducing apparatus and gives an instruction to invert the signal demodulated by the digital demodulating section 19 according to the reproduced signal.

As also shown in the disc of this embodiment, the optical disc of the present invention is provided with the area 24 in which the reproduced signals 0 and 1 are inverted when the signal is reproduced. When this disc is reproduced, an arrangement table 25 indicating the arrangement state of CP signals and a CP signal preceding signal 26 of a specific pattern are recorded in a normally recorded area.

CP signal arrangement information 25 of this specific pattern
When the CP signal preceding signal is reproduced, the optical disc reproducing apparatus of the present invention considers that after the specific pattern, the reproduced signals 0 and 1 are recorded so as to be inverted when the signal is reproduced. In order to correctly reproduce this signal, for example, in the apparatus of the embodiment shown in FIG. 2, the digital demodulation unit 19 is instantaneously controlled so as to demodulate the RF signal into a digital signal and then invert the signal.

In this way, when the signal of the specific pattern is subsequently reproduced, the recorded area is reproduced so that 0 and 1 of the reproduced signal are inverted. In this area, the RF signal is digitally reproduced. Since the digital demodulation unit 19 is set to demodulate the signal and then invert the signal,
It is possible to correctly reproduce the recorded area so that 0 and 1 of the reproduced signal are inverted when the signal is reproduced.

In order to stably reproduce the normally recorded area, 0 and 1 of the reproduced signal when the signal reproduction is performed.
A signal of a specific pattern is also recorded in the area recorded so that and are inverted.

When this signal is reproduced, the optical disk reproducing apparatus of this embodiment demodulates the RF signal into a digital signal, and then instantaneously controls the digital demodulation unit 19 so as to output the signal as it is without inverting it.

As a result, the normal recorded area is reproduced following the signal of the specific pattern, but since the RF signal is demodulated to a digital signal and the signal is output as it is without being inverted, it is correct. Can be played.

Any signal may be used as the signal having a constant pattern for inverting the signal when demodulating the RF signal into a digital signal.

As described above, how to prevent the duplication of the optical disc of the present invention having an area recorded so that 0 and 1 of the reproduced signal are inverted when the signal is reproduced is described. explain.

When the optical disc of the present invention is duplicated on an optical disc medium which can be written only once and can be reproduced by an ordinary reproducing apparatus, the optical disc of the present invention is reproduced by the reproducing apparatus and written based on a signal demodulated into a digital signal. The light is modulated and written on the above optical disk medium.

When the signal is reproduced, 0 and 1 of the reproduced signal
The area recorded so that and are also inverted is reproduced as a normal correct signal because the signal is inverted and output when the reproducing apparatus demodulates into a digital signal.

Therefore, a normal signal which is not inverted is written in the recorded area so that 0 and 1 of the reproduced signal are inverted when the signal is reproduced on the duplicated disc. .

When the reproducing apparatus reproduces the above-mentioned duplicated optical disk, in the area where the signal is recorded so that it is inverted in the regular disk, the signal is inverted and output when demodulating the RF signal into a digital signal. , Does not play properly.

When the signal is reproduced, 0 and 1 of the reproduced signal
Since there is a means for stopping the reproduction unless the recorded area is recorded in the regular area so as to be reversed and is not reproduced correctly, the reproduction or the program operation is automatically stopped.

As described above, the program of the duplicated optical disc cannot be reproduced or operated, and the illegally duplicated optical disc can be prevented from being used.

On the optical disc, generally, signals are spirally recorded from the innermost circumference to the outer circumference. In a CD or the like, a lead-in area is provided on the innermost circumference, and disk index information and the like are recorded.

Also in the optical disc of the present invention, the area recorded so that 0 and 1 of the reproduced signal are inverted when the signal is reproduced corresponds to the lead-in area 32 of the CD as shown in FIG. If it is provided in the inner peripheral portion, it is desirable that it can be quickly discriminated whether or not it is a duplicated optical disk at the start of reproduction.

The copy protection program will be described in more detail below. At step 40a in FIG. 3, the reproduction of the program on the optical disk starts. In step 40b, it is confirmed by a TOC flag or the like whether the disc is compatible with the CP signal. If Yes, the CP signal arrangement information 25 is obtained from the reproduced signal in step 40d as shown in FIG. When it is not step 40e, the process is stopped, and when it is, the process proceeds to step 40f.

In step 40f, the inverted signal is checked in the inverted signal recording area, and in step 40g, C
Check P signal, if not, go to step 40r,
If all the check data have not been completed, the process returns to step 40f. If all the check data has been completed, the process proceeds to step 40p to determine that the disk is a duplicate disk.

If Yes in Step 40g, Step 40
In step h, it is confirmed whether or not the data of the CP signal arrangement information and the physically detected address and angular position of the CP signal match in the normal disk collating unit 33 of FIG.

If the collation is OK in step 40i, step 4
0j, it is checked whether an error or an incorrect signal has occurred in the CP signal arrangement area. If an error of a certain level or more occurs in step 40k, it is determined that the disk is a duplicate disk in step 40p, and if it does not occur, step 40m If all check data are completed, the program is operated in step 40n. If not completed, step 40f
Return to.

When it is determined in step 40p that the disc is a duplicate disc, the display of "duplicate disc" is displayed on the display unit 41 in step 40p, the disc is ejected in step 40s, the operation of the program is stopped, and the data is written in step 40t. The output is stopped and all the operations are stopped in step 40u.

When the address of the recorded area is recorded in the CP signal arrangement area so that 0 and 1 of the reproduced signal are inverted when the signal is reproduced, it is not necessary to record the CP signal preceding signal. .

FIG. 4 shows an example of a master recording apparatus capable of reversing a recording signal during recording. In FIG. 4, 1 is a recording laser, 2 is an optical modulator, 3 is a mirror, 4 is a lens actuator, 5 is a glass plate coated with photoresist, 6 is a spindle motor, 7 is a signal source, and 21 is a recording signal. A reversible recording equalizer 22 is a control unit. A beam expander of a laser optical system for focus control and a laser optical system for recording is omitted.

CP that is normally input separately from input data
The CP signal generator 22a inverts the recording signal based on the signal arrangement information 25. The CP signal arrangement information is recorded on the optical disc together with the input data.

After the CP signal arrangement signal of a specific pattern is generated from the signal source 7, in order to invert the recording signal, the control unit 22 instructs the recording equalizer 21 to invert the signal.

The recording laser 1 includes a laser and a power adjusting element such as a noise eater or an AO modulator,
The power of the laser itself is changed, or the power adjustment element is used to change the power. Record equalizer 21
Has a configuration in which a signal can be inverted by a command from the outside.

The area recorded so that 0 and 1 of the reproduced signal are inverted when the signal is reproduced by the above method can be easily formed without making a major modification to the master recording apparatus. The optical disk of the present invention can be manufactured in a large amount at low cost because it can be manufactured by the same steps as those of the conventional optical disk except the recording of the master disk.

In the optical disc and the optical disc reproducing apparatus of the present invention, it is possible to prevent reproduction of the duplicated disc and prevent duplication of the optical disc.

[0054]

The optical disk of the present invention and the reproducing apparatus for the same are provided with a recorded area on the optical disk so that 0 and 1 of the reproduced signal are inverted when the signal reproduction is performed after the signal of the fixed pattern, After the signal of a certain pattern is detected by the playback device, the function of inverting the signal after demodulating the RF signal into a digital signal and the function of inverting the playback signal, if the signal in the area is not played, the subsequent playback is stopped. The function to do is added.

0 and 1 of the reproduced signal when the signal is reproduced
The signal reproduced by the reproducing apparatus from the area recorded so that and are inverted and digitally demodulated is a regular signal, and when the demodulated signal is recorded on the recordable optical disk medium, the reproduced signal is reproduced when the signal is reproduced. Is recorded so as not to be reversed.

Therefore, if the reproducing device demodulates the RF signal into a digital signal and then inverts and reproduces the signal, the signal is not reproduced as a normal signal and the reproduction is stopped.
The duplicated disc cannot be played back, and illegal duplication can be prevented.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of recording signals on an optical disc according to an embodiment of the present invention.

FIG. 2 is a block diagram of a reproducing apparatus for the disc of the embodiment.

FIG. 3 is a flow chart of a duplicate disk operation prevention program in the embodiment.

FIG. 4 is a block diagram of an example of a recording apparatus for an optical disk master according to the present invention.

FIG. 5 is a block diagram of a conventional optical disc master recording device.

FIG. 6 is a block diagram of a conventional optical disc reproducing apparatus.

[Explanation of symbols]

 1 laser for recording 2 optical modulator 3 mirror 4 lens actuator 5 glass plate coated with photoresist 6 spindle motor 7 signal source 9 optical disk 10 optical pickup 11 spindle motor 12 analog waveform shaping section 14 digital signal processing section 16 focus servo section 17 Tracking servo section 18 Rotation servo section 19 Digital demodulation section 20 Control section 21 Recording equalizer 22 Control section 23 Recording circuit 24 Inversion signal 25 CP signal arrangement information 26 CP signal preceding signal 27 CP signal arrangement information reproducing section 31 Program area 32 Lead-in section 33 collation unit 39 playback / program stop unit 40 step 41 display unit

Claims (7)

[Claims] 1. A reproduced signal of 0 and 1 when the signal is reproduced.
An optical disc having an area recorded so that and are reversed. 2. The optical disc according to claim 1, further comprising a specific signal area corresponding to the recording area prior to the recording area for recognizing the existence of the recording area. 3. The optical disc according to claim 1, wherein the recording area is formed in a lead-in area. 4. A method of manufacturing an optical disk master used for manufacturing the optical disk according to claim 1, wherein the base material to be the optical disk master is coated with a photoresist, and the information to be recorded on the photoresist. A signal having a specific pattern was detected when the photoresist was developed by light intensity-modulated with a signal, and then the photoresist was developed to form uneven pits corresponding to the photosensitivity on the base material serving as the optical disc master. After that, by inverting the information signal to be recorded, a recorded area is formed so that 0 and 1 of the reproduced signal are reversed when the signal is reproduced, and the manufacture of the optical disc master. Method. 5. A method of reproducing an optical disk, which comprises detecting a signal of a specific pattern, demodulating an RF signal into a digital signal, and then inverting the signal. 6. An optical disk reproducing apparatus comprising: a detection means for detecting a signal of a specific pattern; a demodulation means for demodulating an RF signal into a digital signal; and an inverting means for inverting the signal. 7. An optical disk reproducing apparatus according to claim 6, further comprising a function of stopping the subsequent reproduction when the reproduction of the signal in the area where the reproduction signal is inverted is not reproduced.