JPH07121907A - Optical disk and checking apparatus therefor - Google Patents

Abstract

PURPOSE:To obtain an optical disk and a checking apparatus which allows the preventing of any wrong disc copy better. CONSTITUTION:When a setting of a disk 10 is detected with a disk setting detector 12, the detection thereof is reported to a microcomputer 24 to make a reference to addresses AD1-AD3 of a flaw pit DP in a memory 26. Then, a direction for driving is provided to a disk drive section 14 and a pickup drive section 18 from the microcomputer 24 and address parts thereof are read out with a pickup 16. A tracking error signal is supplied to the microcomputer 24 from a head amplifier circuit 20 and a signal processing circuit 22. The tracking error signal increases in any flaw pit DP. When a flaw pit DP exists, a normal disk is determined. Otherwise, a copy disk is identified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc for checking an optical disc such as a CD-ROM in which information such as a TV game is recorded to prevent illegal copying, and a checking device therefor.

[0002]

2. Description of the Related Art For example,
The CD-ROM and the like are manufactured based on the published standard such as "ISO9660". When copy protection is performed according to this standard, a copy protection code is recorded in advance. In other words, if this code is present, it is determined that the disc is a legitimate disc, and if the code is not present, it is determined that the disc is an improper copy disc, and measures such as stopping the reproduction are taken.

However, in such a copy protection method, it is possible to easily make a copy that is accepted as a regular disk by using a copying machine that copies the entire recorded data on the disk. Therefore, we created an original standard different from the standard of the above-mentioned disc,
A method of applying copy protection that makes it unreadable by software that reads a CD-ROM such as "60" is conceivable. However, even if such a method is used, the data is read from the disk in physical frame units, and C
If a copy machine that copies to D-WO is used, any disc will be copied.

By the way, a tracking error is monitored in an IC for a CD player or a CD-ROM drive which is currently on the market, and if the error exceeds a certain level, it is judged that a shock has occurred and the servo gain is determined. Measures to raise the number are taken (for example, "TC9236AF" manufactured by Toshiba Corporation). Alternatively, the amount of reflected light from the disc is monitored, and if the amount of light decreases or rises to some extent and changes at a rate higher than the slew rate, it is determined that the disc has dirt or defects, and the PLL is held or muted. Measures have been taken (for example, "AN8803S manufactured by Matsushita Co., Ltd."
B ").

Therefore, if such a function is effectively used, copy protection can be realized by using a conventional IC without special circuit design. The present invention focuses on these points, and an object of the present invention is to provide an optical disc and a checking apparatus therefor capable of satisfactorily preventing illegal disc copying.

[0006]

To achieve the above object, the first aspect of the present invention is an optical disc in which a large number of pit rows are arranged symmetrically with respect to the track center, and has an asymmetric shape with respect to the track center. Alternatively, at least one scratch pit in which the tracking error signal is obtained is arranged.
It is characterized by including one. A second aspect of the invention is an optical disc in which a large number of pit rows are arranged symmetrically with respect to the track center, and includes at least one scratch pit that has a mirror surface without pits or is similar thereto and that has an increased light amount signal. Characterize.

A third aspect of the present invention is an optical disc check device, comprising: memory means for storing address information of scratch pits formed on the optical disc; and a corresponding portion of the disc corresponding to the address information. A reproducing means for reproducing and obtaining a reproduced signal, and the reproduced signal obtained thereby and the address information are used to detect the presence or absence of the scratch pit, and based on the result, whether the disc is a legitimate disc or an unauthorized copy disc. And a determining means for determining.

[0008]

According to the present invention, at least one scratch pit is formed in the pit according to the normal standard on the optical disk. Since the tracking error signal or the light amount signal increases at this scratch pit portion, the detection is performed by utilizing this. Since the address information of the scratch pit on the regular optical disk is given in advance, it is possible to check the presence or absence of the scratch pit at this address position. Since the scratch pits are not copied, it is not possible to detect the scratch pits at a predetermined address in an unauthorized copy disc. This makes it possible to identify an illegally copied disk.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the optical disk and the checking apparatus therefor according to the present invention will be described in detail below with reference to the accompanying drawings. <First Embodiment> First, a first embodiment of the present invention will be described with reference to FIGS. In this embodiment, a normal disc and a copy disc are distinguished by increasing the tracking error.

Disc FIG. 1 (A) shows a first example of the pit shape of the disc according to the first embodiment, and FIG. 1 (B) shows a tracking error obtained when reading it. The signal is shown. In FIG. 3A, the pit PA in the area on the left side indicated by the arrow FA complies with a normal standard and has a symmetrical width shape with the track TR as the center. On the other hand, the pit PB in the area on the right side indicated by the arrow FB has a shape in which the width is increased on one side (the lower side in the figure in this example) with respect to the track TR.

On the other hand, laser spots S1 to S3 of the three-beam method are applied to the pit row to wobble two spots S.
Subtracting the reflected light amounts of 1 and S3 yields a tracking error signal as is well known. Same figure (A)
In the case of the pit row shown in FIG. 2, since the pit shape is bilaterally symmetrical with respect to the track TR in the area of the normal pit shape indicated by the arrow FA, two wobbled spots S are formed.
The reflected light amounts of 1 and S3 are almost equal. Therefore, the tracking error signal is almost “0” as shown in FIG.

However, in the deformed pit-shaped region indicated by the arrow FB, since the pit shape is asymmetric with respect to the track TR, the reflected light amounts of the two spots S1 and S3 are not equal. Therefore, the tracking error increases, and the signal waveform as shown in FIG.

FIG. 2A shows a second example of the pit shape of the disk according to the first embodiment, and FIG. 2B shows a tracking error signal obtained when reading it. It is shown. In FIG. 4A, the area on the left side indicated by the arrow FA complies with the same standard as the above example. On the other hand, the pit PC in the right area indicated by the arrow FC has a wobbled arrangement with respect to the track TR without changing the pit shape itself.

When a laser beam is applied to such a pit row in the same manner as in the above example, the tracking error signal is almost "0" in the area of the normal pit shape shown by the arrow FA, as shown in FIG. Is. However, in the displaced pit-shaped area indicated by the arrow FC, since the pit position is displaced with respect to the track TR, the reflected light amounts of the two spots S1 and S3 are not equal.
As a result, the tracking error increases and the figure (B)
A signal waveform as shown in can be obtained.

The disk in the first embodiment includes any of the above pit-shaped portions. The scratched pits described above, that is, the pits that cause a tracking error, are added to the data format at positions that do not affect the original disc data. Further, the length of the scratch pit is set so as not to cause any inconvenience in reproduction such as the reproduction operation being stopped by the tracking error signal generated thereby. Furthermore, it is preferable to form the scratch pits at a plurality of positions on the disc. This is because, if there is only one place, there is a possibility that the disc is erroneously recognized as a legitimate disc if the illegally copied disc is dirty or has scratches in the manufacturing process. The more scratch pits are provided, the lower the probability of such misrecognition.

Checking Device Next, an embodiment of the checking device will be described with reference to FIG. The figure shows the main part related to the present embodiment.
The above-mentioned scratch pit DP is formed in AD3. The reproducing apparatus for the disc 10 is provided with a disc set detecting device 12, which detects the presence or absence of a disc set. The rotational drive of the disk 10 is controlled by the disk drive unit 14,
The drive of the pickup 16 that outputs the above-mentioned three laser beams and detects the reflected light of the disc is controlled by the pickup driving unit 18.

The beam detection output side of the pickup 16 is connected to a head amplifier circuit 20, and the head amplifier circuit 20 outputs a light amount signal and a tracking error signal. These signals are supplied to the signal processing circuit 22. A microcomputer 24 is connected to the signal processing circuit 22, and a tracking error signal is supplied to the microcomputer 24. The memory 26 of the microcomputer 24 stores the data of the addresses AD1 to AD3 where the scratch pits are formed. The microcomputer 24 is connected to the display device 28 in addition to the disc set detection device 12, the disc drive unit 14, and the pickup drive unit 18.

Next, the operation of the checking apparatus according to this embodiment will be described with reference to the flowchart of FIG. First, when the disk 10 is set and detected by the disk set detection device 12, the fact is notified to the microcomputer 24 (step SA). On the basis of the notification, the microcomputer 24 refers to the addresses AD1 to AD3 of the scratch pit DP stored in advance in the memory 26. Then, a drive instruction is issued from the microcomputer 24 to the disk drive unit 14 and the pickup drive unit 18, and the first address AD1
The reading of the pit train for is performed. That is, the disk 10 and the pickup 16 are driven so that the pit train at the address AD1 is sequentially irradiated with three beam spots.

The reflected light of each beam spot is received by the pickup 16, converted into an electric signal and supplied to the head amplifier circuit 20. In the head amplifier circuit 20,
A tracking error signal and a light amount signal are respectively obtained from the incident signal and supplied to the signal processing circuit 22. Then, the tracking error signal is supplied from the signal processing circuit 22 to the microcomputer 24.

As described above, since the tracking error signal increases at the scratch pit DP portion, the presence or absence of the scratch pit DP is detected using this relationship (step S).
B). Such a detection operation of the scratch pit DP is performed at the address A.
D2 and AD3 are sequentially performed. When the scratch pit DP is detected at the three addresses AD1 to AD3 (step SC), the microcomputer 24 determines that the disk 10 is a normal disk, and thereafter, the normal reproduction operation is executed (step SC). SD).

Next, the case of reproducing a disc obtained by copying the regular disc 10 will be described. When copying the regular disc 10, first, the regular disc 10 is reproduced by a CD-ROM drive or the like, and the obtained reproduction signal is recorded on a CD-WO or the like by a recording device. In this case, the data is copied with the flaw pit portion being error-corrected, so that there is no flaw pit. In other words, it looks like a good copy, but it has no scratch pits.

When such a copy disc is set in the reproducing apparatus shown in FIG. 3, addresses AD1 to AD1 are similarly set.
The portion of AD3 is accessed and the tracking error signal is detected. However, in the case of the copy disc, since the scratch pit DP does not exist, the tracking error signal is not detected either. Therefore, the microcomputer 24 determines that the disc is a copy disc, and instructs the display device 28 to display that fact, and also instructs the signal processing circuit 22 to stop the signal output (step S).
E).

Thus, in the case of a copy disc, the reproducing operation is stopped. Therefore, copying of the disc is consequently prevented. Even if a copying machine that makes a copy in physical frame units is made, some appropriate data will be inserted in the portion where the tracking error has occurred. Therefore, when the copy disc is reproduced, no tracking error occurs in the scratched pit portion, and as a result, reproduction is prevented.

Further, if the disc reproducing apparatus does not have the above-mentioned checking device or the address information of the scratch pit is incorrect, the seek may be performed even if the disc is read due to the existence of the scratch pit. An error or data error comes out and it stops. In other words, according to the present embodiment, the reproducing apparatus is also required to have a predetermined function, so that copy protection can be applied also from this point.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment or components corresponding to the first embodiment will be designated by the same reference numerals.
In the first embodiment, a regular disc and a copy disc are distinguished by increasing the amount of reflected light.

FIGS. 5A to 5C show examples of the pit shape of the disc according to the second embodiment. In the figure, the pits PA in the left and right areas indicated by the arrow FA comply with the normal standard. In contrast, the arrow FD
The pit PD in the area indicated by is the characteristic portion of this embodiment. In the example of FIG. 9A, the length of the pit PD is shorter than, for example, 3T which is the shortest rule in EFM. In the example of FIG. 7B, the mirror surface portion PE is formed by eliminating the pit. In the example of FIG. 6C, the pit P is changed by changing the exposure amount of an exposure device (not shown) when forming the pit.
The depth of F is shallow. The mirror surface portion PE is also called a scratch pit for convenience.

When the laser spots S1 to S3 are applied to the pit train and the amount of reflected light is obtained in the same manner as in the first embodiment, a light amount signal as shown in FIG. This light quantity signal is obtained by adding all photoelectric conversion signals of a four-division light receiving element (not shown) that receives the reflected light of the central laser spot S2 or the photoelectric conversion signals of the light receiving elements of the laser spots S1 and S3. Obtained as a sum. As shown in the figure, the amount of reflected light is increased in the portions of the scratch pits PD to PF because the influence of the mirror surface is great.

The disk in the second embodiment includes any of the above pit-shaped portions. Incidentally, the scratch pits as described above, that is, the scratch pits that cause an increase in the amount of reflected light, are added to a position on the data format that does not affect the original disc data, as in the first embodiment. There is. Further, the length of the scratch pit is such that the reproduction operation is not stopped by the light amount signal generated thereby and the reproduction pit does not occur. It is also the same as forming the scratch pits at a plurality of positions on the disc.

The disc checking device of the second embodiment may have the same structure except that the light quantity signal is used instead of the tracking error signal of the device of the first embodiment.

<Specific Example> Next, a specific example of a commercially available disk signal processing IC will be described. For example, in "TC9236AF" manufactured by Toshiba, tracking error is constantly monitored, and when the absolute value of the difference between a certain threshold value and the tracking error exceeds a predetermined value, a detection signal to that effect is output. ing. Figure 3
If input to the microcomputer 24 of
The above-described check operation is possible. Further, in the same IC, when the absolute value of the difference between the light amount level and the slew rate limiting signal exceeds a predetermined value, a detection signal to that effect is output. If this is input to the microcomputer 24 of FIG. 3, the check operation can be performed in the same manner.

Next, a head amplifier IC "AN" manufactured by Matsushita
8803SB "outputs a detection signal to that effect when the tracking error deviates from a predetermined range, and outputs a signal to that effect when the reflected light amount increases and the RF signal level relatively decreases. It is like this.
By using these signals, the above-described check operation can be performed similarly.

<Other Embodiments> The present invention is not limited to the above embodiments, and includes, for example, the following. (1) In the above-described embodiment, the address information in which the scratch pit is formed is stored in advance in the checking device side. However, the address information of this scratch pit is stored in a predetermined position of the disc, and the checking device sets the disc. Sometimes, the predetermined position may be read first. In this way, the address of the scratch pit can be changed for each type of disc, so that analysis of the copy protection of the disc becomes difficult and the effect of preventing illegal copying can be improved.

(2) The scratch pits of the first embodiment in which the tracking error signal is obtained and the scratch pits of the second embodiment in which the light amount signal is obtained may be mixed in one disk. By doing so, it is possible to improve the reliability of detection of the copy disk.

(3) According to the general standard of CD, the error should not exceed a certain range, but the standard can be set by appropriately setting the length of the scratch pit as described above. It is possible not to violate. Also, in the field of TV games and the like, it is usually not necessary for a game disc to be reproducible on any device other than the replay game console. Therefore, it is not necessary to consider compatibility with a disc used for a personal computer or the like, and there is no problem in practical use.

(4) In the above embodiment, the presence or absence of scratch pits is determined when the disc is set, and it is checked whether or not the disc is a copy disc. However, when there is an instruction to reproduce the disc, the check is performed. However, it may be appropriately set if necessary.

[0036]

As described above, according to the optical disc and the checking apparatus therefor of the present invention, it is possible to form a flaw pit at a predetermined address of the optical disc and check the presence or absence of the flaw pit. There is an effect that it is possible to detect and realize good copy protection.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a first example of a pit shape and its tracking error signal in a first embodiment of an optical disc according to the present invention.

FIG. 2 is an explanatory diagram showing a second example of a pit shape and its tracking error signal in the first embodiment.

FIG. 3 is a block diagram showing an embodiment of a check device according to the present invention.

FIG. 4 is a flowchart showing the operation of the checking device.

FIG. 5 is an explanatory diagram showing an example of a pit shape and how the light amount changes in the second embodiment of the present invention.

[Explanation of symbols]

10 ... Disc, 12 ... Disc set detection device, 14
... disk drive section, 16 ... pickup, 18 ... pickup drive section, 20 ... head amplifier circuit, 22 ... signal processing circuit, 24 ... microcomputer, 26 ... memory,
28 ... Display device, AD1 to AD3 ... Address of scratch pit, DP, PB to PF ... Scratch pit, FA ... Arrow indicating normal pit recording area, FB, FC ... Arrow indicating scratch pit recording area, PA ... Normal Pits, S1 to S3 ... Laser spots.

Claims (3)

[Claims] 1. An optical disc in which a large number of pit rows are arranged symmetrically with respect to a track center, and at least one scratch pit having an asymmetric shape or arrangement with respect to the track center and providing a tracking error signal. An optical disc comprising: 2. An optical disc in which a large number of pit rows are arranged symmetrically with respect to the track center, and includes at least one scratch pit which has a mirror surface without pits or is similar thereto and has an increased light quantity signal. Optical disc. 3. A memory means for storing address information of a scratch pit formed on the optical disc according to claim 1 and reproducing the corresponding portion of the disc corresponding to the address information. Using the reproducing means for obtaining a reproduced signal, the reproduced signal obtained thereby, and the address information, the presence or absence of the scratch pit is detected, and based on this result, it is judged whether the disc is a legitimate disc or an unauthorized copy disc. An optical disk checking device comprising: a discriminating means.