JPH1166708A - Optical disk, optical disk recorder and optical disk reproducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the unauthorized duplication of an optical exclusive for reproduction by making pit lengths of the optical disk minutely variable. SOLUTION: Aftrer an input signal is subjected to EMF modulation in an EMF encoder, it is inputted to a duty correcting circuit 12, applied with duty corrections and transmitted to an E/O modulation controller to control the output of a laser beam and then cuttings are performed. When the signal is to be recorded in a copy guard area being an objective area where pit lengths are made variable regularly and minutely duty is corrected in the duty correcting circuit 12 by inputting the input signal from the EMF encoder and the delayed signal obtained by delaying the signal in a programable delay element 121 to an AND circuit (or an OR circuit) 122 and by ADDing (or ORing) them. An optical dick reproducer judges whether an optical disk is the disk of an unauthorized duplication or not by detecting the amount of change in the duty while reproducing the disk and comparing this amount of change with the prescribed amount of the change of the minute fluctuation of duty which should be recorded on a formal optical disk to perform a necessary action.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the prevention of illegal copying of an optical disk. More specifically, the present invention relates to an optical disk having an unauthorized copy prevention function, a recording device for recording a signal on a master disk of the optical disk, and a reproducing device for the optical disk.

[0002]

2. Description of the Related Art In a compact disk (CD), which is a read-only optical disk, a recording signal is EFM-modulated.
Pits (or lands) having a length of 3T to 11T are recorded on the disk. Here, T is one channel bit period, that is, the length of a pit (land) that generates a reproduction signal having a reproduction clock length. Hereinafter, in this specification, T
Is used in this sense.

In order to record a signal after EFM modulation as a pit having a length of 3T to 11T, the duty cycle of the signal after EFM modulation is corrected. this is,
This is signal correction in consideration of the beam waist of the laser beam. That is, when the disk master is laser-cut according to the signal after the correction, the correction is performed so that the pits are accurately formed with a length of 3T to 11T. For this correction, a duty correction circuit is provided between the EFM encoder and the E / O modulator controller in the laser cutting device (recording device) of the master disk.

[0004] Unauthorized copying of an optical disk is performed, for example, by removing a protective film from a properly manufactured optical disk, plating the exposed aluminum reflective layer as an electrode to form a stamper, and using this stamper to perform injection. It is performed by a method of illegally duplicating an optical disk by a molding method or the like. Alternatively, the data of the optical disk manufactured properly is read, and the CD-R is read in accordance with the data.
A method of duplicating the information by recording it in a computer has been used.

[0005]

There is a demand to prevent unauthorized copying of a read-only optical disk. In addition, there is a demand for identifying an illegally duplicated optical disk. Further, there is a demand to provide a reproducing apparatus having a function of canceling reproduction of an unauthorized disk or the like. An object of the present invention is to meet such a demand.

[0006]

SUMMARY OF THE INVENTION According to the present invention, accurate transfer cannot be performed by the above illegal copy method, and if the transfer cannot be performed accurately, a duty fluctuation component different from that of a regular disc is detected. The pit length of the optical disk is provided with a small variation in advance, and it is determined whether the disk is a regular disk based on whether or not the small variation is properly detected. Based on the determination result, cancellation of reproduction or the like is performed. Is what you do.

[0007] The first aspect of the present invention is an optical disc in which the length of a pit modulated by recording information is provided with a regular and minute fluctuation. In other words, the optical disk has a pit on which a signal modulated by a predetermined method is recorded, the length of which is slightly longer or shorter than the original length in accordance with a predetermined rule.

According to a second aspect of the present invention, there is provided the optical disk according to the first aspect, wherein the minute fluctuation is periodic. The invention according to claim 3 is the optical disk according to claim 1, wherein the minute fluctuation is modulated by a predetermined code. The invention according to claim 4 is the optical disc according to claim 2 or 3, wherein the minute fluctuation exists in a part of a recording track. That is,
This is an optical disc in which the pit length of at least a part of a track on which a signal is recorded is slightly longer or shorter than the original length in accordance with a predetermined rule. A fifth aspect of the present invention is the optical disc according to the fourth aspect, wherein the minute fluctuation exists in a predetermined range in a radial direction of the optical disc. That is, the optical disk is such that at least a part thereof is within a certain range in the radial direction. A sixth aspect of the present invention is the optical disc according to the second or third aspect, wherein the minute fluctuation exists over the entire surface of the optical disc. According to a seventh aspect of the present invention, in the optical disk according to any one of the second to fifth aspects, the minute variation exists in a lead-in area of the optical disk. An eighth aspect of the present invention is the optical disk according to any one of the second to fifth aspects, wherein the minute fluctuation exists in a lead-out area of the optical disk. A ninth aspect of the present invention is the optical disk according to any one of the second to fifth aspects, wherein the minute variation exists in a program area of the optical disk.

According to a tenth aspect of the present invention, there is provided a duty changing means for changing a duty cycle of a recording signal which is inputted and outputted, and a control means for regularly and minutely changing the output of the duty changing means. An optical disc recording apparatus characterized by the above-mentioned. That is, duty changing means for changing and outputting the duty cycle of the input recording signal, and control means for minutely changing the degree of change by the duty changing means according to a predetermined rule,
An optical disk recording device having

An eleventh aspect of the present invention is the optical disk recording apparatus according to the tenth aspect, wherein the control means periodically and minutely changes the output of the duty changing means. A twelfth aspect of the present invention is the optical disc recording apparatus according to the tenth aspect, wherein the control means modulates an output of the duty changing means with a predetermined code. According to a thirteenth aspect of the present invention, there is provided an optical disc recording apparatus according to the eleventh or twelfth aspect, wherein the control means slightly varies an output of the duty changing means with respect to a recording signal recorded in a predetermined area on the disk. is there. According to a fourteenth aspect of the present invention, there is provided the optical disc recording apparatus according to the thirteenth aspect, wherein the control means slightly varies an output of the duty changing means with respect to a recording signal recorded in a predetermined range in a radial direction on the disk. .

According to a fifteenth aspect of the present invention, an optical disk is provided with a detection circuit for detecting a duty fluctuation component of a reproduction signal of the optical disk, and identification means for identifying a regular fluctuation of the duty fluctuation component. It is a playback device. An invention according to claim 16 is the optical disk reproducing apparatus according to claim 15, further comprising a duty fluctuation component suppressing circuit for suppressing the detected duty fluctuation component by feedback. According to a seventeenth aspect of the present invention, there is provided an optical disc reproducing apparatus according to the fifteenth or sixteenth aspect, wherein the detecting circuit is a circuit for detecting an integral value of an EFM signal reproduced from the optical disc.

The invention according to claim 18 is an optical disc reproducing apparatus in which the length of pits arranged in a predetermined area has regular minute fluctuations, wherein the predetermined area is changed according to the mounting of the optical disc. A search means for performing a search scan, a detection circuit for detecting the minute change in the search scan by the search means, and an output from the detection circuit, and a regular disk based on the minute change in the predetermined area. An identification means for identifying whether or not there is an optical disk. For example, if the detected minute change is the same as the minute change that should have been recorded on the regular disk, the mounted disk can be identified as the regular disk. This is because a disc copied illegally does not accurately copy the above-mentioned minute fluctuation.

The invention of claim 19 is the invention according to any one of claims 15 to 18, further comprising a prohibition means for prohibiting the reproduction of the disc when the discrimination means identifies that the disc is not a regular disc. An optical disc reproducing apparatus characterized by having: For example, it is means for discharging the disk or stopping the rotation of the spindle motor. According to a twentieth aspect of the present invention, in any one of the fifteenth to eighteenth aspects, a display means for displaying that the disc is not a regular disc when the discriminating means identifies the disc as not a regular disc. An optical disc reproducing apparatus characterized by having:

[0014]

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

Recording device. FIG. 1 is a block diagram showing a recording apparatus for laser-cutting an optical disc master according to the embodiment, and FIG. 2 is a block diagram showing details of a duty correction circuit 12 in FIG.

The input signal is input to the EFM encoder 11
After being FM-modulated, the signal is input to the duty correction circuit 12, and subjected to the duty correction described in the section of the prior art. In accordance with the data after the EFM modulation and the data after the duty correction, the E / O modulation controller 13
The modulator 15 is controlled. The laser beam output from the laser 14 is modulated by the E / O modulator 15 so that the master 91
Of the photoresist layer. Thus, the photoresist layer can be cut so as to correspond to the data after the EFM modulation and the data after the duty correction.

When a signal is recorded in a copy guard area, which is a target area in which a pit length is to be provided with a regular small fluctuation, a signal to that effect is sent from the controller 10 to the duty correction circuit 12. This signal, in this example,
As shown in FIG. 2, this is a signal for controlling the amount of delay of the programmable delay element 121, whereby the duty correction amount is controlled. That is, in the duty correction circuit 12, E
An input signal from the FM encoder 11 and a delay signal obtained by delaying the input signal by the programmable delay element 121 are:
The signal is input to an AND circuit (or an OR circuit) 122 and is subjected to logical product (or logical sum). As a result, a signal whose duty has been corrected is output as shown in the lower right part of FIG.
Therefore, by controlling the data sent from the controller 10 to the programmable delay element 121 so as to follow a desired rule, the duty cycle can be minutely changed so as to follow the desired rule.

With respect to the EFM signal whose duty cycle fluctuates, the slice level at the time of reproduction changes correspondingly as shown in FIG. If the correction amount of the pit duty is fixed, the slice level can be changed to a rectangular shape as shown in FIG. Further, if the correction amount of the pit duty is changed continuously, the slice level can be changed sinusoidally (FIG. 4B) or triangularly changed (FIG. 4B). . In the case of a rectangle, desired data can be represented by a combination of “1” and “0”. The desired data is, for example, security information. The frequency range of each waveform shown in FIG. 4B is, for example, when the disc has a recording density twice as high as the physical format of a compact disc and the linear velocity of laser cutting is 0.9 ± 0.1 m / sec. Is 10
It is 0 Hz to 50 KHz. If the frequency is less than 100 Hz, the surface runout component of about 10 Hz cannot be separated.
If the frequency exceeds 100 Hz, the frequency component of 200 KHz corresponding to 11T cannot be separated by the low-pass filter. The same applies when the disc follows the physical format of a compact disc and the linear velocity of laser cutting is 1.2 m / sec.

Further, the frequency of the sine wave or the like is changed, for example, as shown in FIG.
May be used. This makes it possible to incorporate desired data into the frequency. For a sine wave,
Modulation such as FM modulation may be performed.

Although the lead-in area 91a is shown in FIG. 1 as a copy guard area, it is not necessarily limited to the lead-in area 91a as described later. The fact that the laser beam irradiated via the objective lens 16a is positioned in the copy guard area can be detected by inputting a signal of the position sensor 17 for detecting the position of the optical system 16 to the controller 10. it can.

Reproducing device. FIG. 3 shows an optical disk 95 created using a master cut by the recording apparatus described above.
FIG. 2 is a block diagram showing a reproducing apparatus for reproducing the recorded signal of FIG.

The reflected light from the disk is photoelectrically converted by an optical pickup 51, and then sent to an RF amplifier 52 to be output as an RF signal. This RF signal is a CD / CD-ROM
The signal is input to the decoder 53, demodulated into an EFM signal, and output.

The EFM signal output from the CD / CD-ROM decoder 53 is supplied to a slice level controller.
It is input to 54 and integrated. This integral value corresponds to the duty change amount. During normal playback, this integral value is R
The slice level is controlled by being fed back to the F amplifier 52, and as a result, the quality of the RF signal output from the RF amplifier 52 is improved.

When reproducing the copy guard area, the output of the slice level controller 54 is switched from the RF amplifier 52 to the duty detection decoder 55 in accordance with an instruction from the controller 50. It should be noted that the playback device may first be configured to read a predetermined copy guard area when a disc is loaded.

By the above switching, the duty change amount is input to the duty detection decoder 55, and is compared with a predetermined change amount that should have been recorded on the regular disk.
The result of this comparison, that is, the result of comparison as to whether or not the amount of change that matches the amount of change that should have been recorded on the authorized disk, is sent to the controller 50.

When a signal (non-detection) is input from the duty detection decoder 55 to the effect that the same amount of change as that of the regular disk has not been detected, the controller 50 determines that the illegally copied disk has been mounted. Then, for example,
The spindle motor M2 is stopped, a false display indicating that the disk is illegal is displayed on the display panel 59 to warn the user, and the disk ejector 58 is actuated to perform necessary processing such as discharging the duplicate disk.

Although the lead-in area 95a is shown in FIG. 3 as a copy guard area, it is not necessarily limited to the lead-in area 95a but may be a program area as described later. In this case, it may be a part of a specific area of the program area, or may be over the entire circumference. Further, the fact that the laser beam irradiated on the optical disc 95 is located in the copy guard area can be detected by inputting a signal from a position sensor (not shown) to the controller 50.

Copy guard area. FIG.
2 shows an example of a copy guard area in the area. For example, a copy guard area may be provided in the lead-in area 95a or the lead-out area. When a copy guard area is provided in a lead-in area where a current playback device reads a signal first, it is possible to first determine whether the disc is authentic.

Further, a copy guard area may be provided in an inner buffer or an outer buffer where no signal is recorded. A copy guard area can be provided at an arbitrary position. In this case, if the information related to the information recorded at the arbitrary position is incorporated as shown in FIG. 4B, the associated information can be reproduced at the same time. Become. If the reproducing apparatus is configured to read the copy guard area first, it is possible to identify the duplicated disc at the time of loading the disc and take necessary measures such as discharging the disc.

[0030]

The minute fluctuation recorded on the optical disk of the present invention cannot be accurately transferred by a method generally used for illegal copying. For this reason, it is determined whether the disc is an illegally duplicated disc or a legitimate disc based on the presence or absence of the minute fluctuation and whether or not the minute fluctuation matches the minute fluctuation that should have been recorded on the authorized disk. can do. Also, based on the result, the reproduction of the unauthorized disk can be canceled.

[Brief description of the drawings]

FIG. 1 is a block diagram of a recording apparatus for a master disc of an embodiment.

FIG. 2 is a block diagram showing details of a duty correction circuit 12 in FIG. 1;

FIG. 3 is a block diagram of a disk reproducing apparatus according to the embodiment.

4A is an explanatory diagram showing a change in a slice level during reproduction, FIG. 4B is a waveform diagram illustrating various minute fluctuations,
(C) is an explanatory view showing a method of recording data by modulating a sine waveform diagram of minute fluctuation.

FIG. 5 is an explanatory diagram exemplifying a recording position of a pit or a pit row for preventing unauthorized copying.

[Explanation of symbols]

 91 master disc 95 optical disc

Claims (20)

[Claims] 1. An optical disk characterized in that pits modulated by recording information are provided with regular minute fluctuations in the length of pits. 2. The optical disc according to claim 1, wherein the minute fluctuation is periodic. 3. The optical disk according to claim 1, wherein the minute fluctuation is modulated by a predetermined code. 4. The optical disc according to claim 2, wherein the minute fluctuation exists in a part of a recording track. 5. The optical disc according to claim 4, wherein the minute fluctuation exists in a predetermined range in a radial direction of the optical disc. 6. The optical disk according to claim 2, wherein the minute fluctuation exists over the entire surface of the optical disk. 7. The optical disk according to claim 2, wherein the minute fluctuation exists in a lead-in area of the optical disk. 8. The optical disk according to claim 2, wherein the minute fluctuation exists in a lead-out area of the optical disk. 9. The optical disk according to claim 2, wherein the minute fluctuation exists in a program area of the optical disk. 10. A printing apparatus comprising: a duty changing means for changing a duty cycle of a print signal which is input and output by a print signal; and a control means for regularly and minutely changing the output of the duty changing means. Optical disk recording device. 11. The optical disk recording apparatus according to claim 10, wherein said control means periodically and minutely changes the output of said duty changing means. 12. The optical disk recording apparatus according to claim 10, wherein said control means modulates an output of said duty changing means with a predetermined code. 13. The control device according to claim 11, wherein the control unit slightly changes an output of the duty changing unit with respect to a recording signal recorded in a predetermined area on a disk. Optical disk recording device. 14. The optical disk recording method according to claim 13, wherein said control means slightly varies an output of said duty changing means with respect to a recording signal recorded in a predetermined radial direction on the disk. apparatus. 15. An optical disk reproducing apparatus comprising: a detection circuit for detecting a duty fluctuation component of a reproduction signal of an optical disk; and an identification unit for identifying a regular fluctuation of the duty fluctuation component. 16. The optical disc reproducing apparatus according to claim 15, further comprising: a duty fluctuation component suppressing circuit for suppressing the detected duty fluctuation component by feedback. 17. The optical disc reproducing apparatus according to claim 15, wherein the detection circuit is a circuit for detecting an integrated value of an EFM signal reproduced from the optical disc. 18. A reproducing apparatus for an optical disk in which the length of pits arranged in a predetermined area has regular minute fluctuations, wherein a search means for searching and scanning the predetermined area according to the mounting of the optical disk. A detection circuit for detecting the minute change in the search scan by the search means; receiving an output from the detection circuit to determine whether or not the disc is a regular disc based on the minute change in the predetermined area. An optical disc reproducing apparatus, comprising: an identification unit for identifying; 19. The apparatus according to claim 15, further comprising: a prohibition unit for prohibiting reproduction of the disc when the discrimination unit identifies the disc as not a regular disc. Optical disk playback device. 20. The display device according to claim 15, further comprising: display means for displaying that the disc is not a regular disc when the discrimination means identifies the disc as not a regular disc. An optical disc reproducing apparatus characterized by the above-mentioned.