JP3656340B2 - Optical disc and its identification device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical disc used for a game disc such as a TV game and an identification device thereof.
[0002]
[Prior art]
In general, software products such as read-only optical disks can be easily copied to other media and models, and even copyrighted data can be easily copied and modified, and copyright infringement easily occurs. For this reason, a large number of illegally copied products are rampant centering on software such as game applications, and there is a strong demand for a method for preventing the illegally copying.
For this reason, various preventive measures have been taken against copying of software product media, and many prevention techniques have been proposed. These copy protection technologies are roughly classified into logical methods and physical methods.
[0003]
The physical method is basically that the software medium itself writes some physical code on the external medium, and is generally more effective as a copy prevention measure. In other words, in order to write a unique physical mark, very advanced manufacturing equipment such as modulation of fine pits is required, which requires expensive investment, but the physical method is relatively less than the logical method. The copy protection effect is powerful.
[0004]
As an example of this type of physical copy prevention method, a production lot number and a serial number are marked for each disc after production. This marking is performed, for example, by forming a pit with a laser (Japanese Patent Laid-Open No. 8-124219) or by cutting a barcode-like groove on the inner peripheral mirror surface (Japanese Patent Laid-Open No. 6-203212). Further, as shown in Japanese Patent Laid-Open No. 61-178732, a unique mark is made on the software storage medium itself after the disk is manufactured, and for example, a physical mark [pseudo pit] is formed by manipulating the pit of the optical disk. Since it cannot be copied, it can be identified as a genuine product.
[0005]
[Problems to be solved by the invention]
However, writing the barcode serial number after manufacturing the disc in this way can be done with relatively simple equipment and at a low cost, but it is also easy when manufacturing illegal copies, and illegal copy discs. There was a problem that the preventive effect on the production of was not sufficient.
The present invention focuses on the above-described problems and has been devised to effectively solve this problem. The purpose of the present invention is to use a relatively inexpensive groove forming facility and to build on a normal groove shape. It is another object of the present invention to provide an optical disc and a discriminating apparatus that make it difficult to make a copy by forming a unique groove shape.
[0006]
[Means for Solving the Problems]
According to the first aspect of the present invention, in the optical disk in which a groove corresponding to a barcode is formed after manufacturing the disk, the shape of the groove is modulated at a predetermined frequency in the depth direction, and the groove corresponds to the barcode. The first information and the second information by the shape modulation of the groove are included.
[0007]
The invention defined in claim 2 is an optical disk in which a groove corresponding to a barcode is formed after manufacturing the disk, the bottom of the groove is modulated in a wavy shape, and the first information by the groove corresponding to the barcode; Second information by wave-like modulation of the bottom of the groove is provided.
According to a third aspect of the present invention, there is provided a discriminating apparatus for identifying an optical disk as defined in the first aspect, wherein a pickup means for optically detecting the groove and a reflected light quantity detecting means for detecting a reflected light quantity obtained by the pickup means. An amplitude detecting means for detecting the amplitude of the reflected light amount, an amplitude comparing means for comparing an output signal from the amplitude detecting means with a predetermined reference value, and determining whether the optical disk is correct or not based on a comparison result of the comparing means It is comprised so that the judgment means to perform may be provided.
[0008]
According to a fourth aspect of the present invention, there is provided a discriminating apparatus for identifying an optical disc according to the second aspect, wherein a pickup means for optically detecting the groove and a tracking error detection for detecting a tracking error signal from the output of the pickup means. Means, zero cross counting means for counting zero crosses of the tracking error signal, timer means for measuring the detection time of the tracking error signal, the number of zero crosses measured within a predetermined period measured by the timer means, and a predetermined number A zero cross count value comparing means for comparing with a reference value and a judging means for judging whether the optical disk is correct or not based on the comparison result of the comparing means are provided.
[0009]
According to the invention defined in claims 1 and 3, the optical disk of the present invention is rotated, the groove portion corresponding to the bar code is irradiated with the laser beam from the pickup means, and the engraved bar code data is detected by the reflected light amount. The signal is detected as data by the means, the amplitude comparison means compares it with a predetermined reference value, the output signal is taken into a judgment means made of, for example, a microcomputer, etc. Judge as genuine.
If the barcode modulation signal cannot be detected, it is determined that the optical disk is an illegal optical disk, and the reproduction is stopped and the disk is ejected.
[0010]
According to the invention defined in claims 2 and 4, the optical disk of the present invention is rotated, the groove corresponding to the bar code is irradiated with the laser beam from the pickup means, and the signal of the bar code data engraved is tracked. Input to the error detection means and output a tracking error signal. From this output signal, the zero cross counting means counts the number of track crossings, the zero cross count value comparing means compares it with a reference value, and based on this result, the judging means judges whether the optical disk is correct or not. For example, when a signal modulated with a bar code can be detected, the optical disc is determined to be a genuine product, and when it cannot be detected, it is determined to be an illegal product. For example, playback is stopped and the optical disc is ejected. To do.
As a matter of course, the identification device has a barcode identification means for identifying the barcode itself, and also determines whether or not there is a barcode code unique to the disc.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an optical disk and an identification apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
First, an optical disk and its identification device defined in claims 1 and 3 will be described. FIG. 1 is a plan view showing an optical disk, and FIG. 2 is a partially enlarged view showing a conventional optical disk and a first optical disk of the present invention.
[0012]
2A is a partially enlarged view showing a conventional optical disk, and FIG. 2B is a partially enlarged view showing a first optical disk of the present invention. Here, in order to clarify the difference between them, the conventional optical disk is shown. The structure of
The optical disc 1 of the present invention has a clamp hole 2 as an opening into which the rotation shaft is fitted at the center thereof, and forms a clamp region 3 and a barcode-like groove 4 that come into contact with the turntable toward the outer periphery. It mainly has an identification area 5 and a data area 6 for recording data.
[0013]
FIG. 2 shows a cross-sectional view of the identification region 5 where the barcode-like groove 4 is formed. This portion is configured by sequentially laminating an aluminum layer 8 and an overcoat layer 9 on a disk substrate 7 made of, for example, polycarbonate resin. The aluminum layer 8 is formed with a permanent groove 4 that is not erasable and obtained by converting ID information such as a manufacturing lot number and a serial number of the optical disk into a barcode. Such a groove 4 can be easily formed by the technique disclosed in, for example, Japanese Patent Application Laid-Open No. 6-203212. For example, after the optical disk is manufactured, the laser light that is turned on / off corresponding to the barcode pattern shape is used for By irradiating the aluminum layer 8 in the identification region 5 while rotating the disk, the groove 4 having the barcode pattern shape can be formed radially.
Here, it should be noted that in the case of the optical disk shown in FIG. 2A, the aluminum layer 8 is completely penetrated up and down, whereas a hole shown in FIG. In the optical disc 1 of the present invention, the groove 4 portion of the aluminum layer 8 does not penetrate, and the depth is varied to modulate the depth. An enlarged view of this portion is shown in FIG. 3 (A). The groove 4 is modulated and has different depths. In the figure, the dotted line indicates the groove shape of the conventional structure.
[0014]
FIG. 4 is a schematic configuration diagram showing a groove forming apparatus for forming the grooves of the optical disk described above. First, groove data as shown in FIG. 5A is generated from a barcode generator 10 that generates groove data corresponding to a barcode serving as a script, and a laser output from the laser light source 11 based on the groove data. The light L1 is turned on / off. If the aluminum layer of the disk is cut with the laser light L1, a conventional groove structure as shown in FIG. 2A can be obtained, but here, the laser light L1 is modulated. That is, a modulation signal having a frequency considerably different from the barcode data transfer rate, for example, a significantly lower frequency, is generated from the modulation signal generator 12, and this modulation signal is input to the laser light intensity modulator 13.
[0015]
Then, the modulator 13 modulates the laser light L1 with a modulation signal to add strength to the laser light. For example, when a sine wave having a frequency much lower than the barcode data transfer rate shown in FIG. 5B is used as the modulation signal, the intensity of the modulated laser beam L2 is shown in FIG. 5C. The intensity has changed. In the figure, the dotted line represents the laser light intensity when forming the conventional groove structure.
By irradiating the modulated laser beam L2 onto the aluminum layer 8 of the optical disc, the barcode-like groove 4 modulated in the depth direction as shown in FIG. 5D can be formed. Therefore, such an optical disc includes first information obtained from a bar code represented by the groove itself and second information represented by a modulation state in the depth direction of the groove.
[0016]
Next, an identification device for identifying correctness of the first optical disc will be described. FIG. 6 is a block diagram showing a first identification device according to the present invention. This device is provided together with a disk reproducing device, and some components, for example, pickup means are also used. First, the playback device 14 will be briefly described. The playback device 14 has a rotary table 16 that is rotated by a spindle motor 15 to rotate the optical disc 1. Pickup means 17 is provided which is movable. The signal obtained by the pickup means 17 is converted into a data signal (RF signal) by the light detection circuit 18 and input to the reproduction control means 19 made of, for example, a microcomputer. The reproduction control means 19 performs operation control and reproduction control of the entire apparatus.
[0017]
On the other hand, the discriminating apparatus 20 of the present invention has a pick-up means 17 that is also used as the reproducing apparatus 14, and inputs the output to the reflected light quantity detecting means 21 to obtain a light quantity signal.
This light quantity signal is branched into two, one of which is led to the barcode identifying means 25 side in order to extract the first information. That is, this branch signal is input to the barcode comparator 24 for comparison with the barcode reference value Vt via the amplifier 22 and the limiter 23, and is binarized. The binarized output signal is input to the barcode decoder 25 so as to obtain corresponding barcode data.
[0018]
On the other hand, in order to obtain the second information, the other branched light quantity signal is inputted to the amplifier 26, and its output is connected to, for example, a detector 27 as an amplitude detecting means for detecting the amplitude. The output of the detector 27 is connected to an amplitude comparator 30 as an amplitude comparison means through a capacitor 28 for cutting a direct current component and a low pass filter 29 for cutting a high frequency component. The amplitude comparator 30 binarizes the amplitude of the input light amount signal using a predetermined modulation reference value Vtm as a threshold, and the output signal is determined by a determination unit 31 made of, for example, a microprocessor. To determine whether or not there is modulation and whether or not the optical disc is a genuine product. In this determination, the output signal from the previous barcode decoder 25 is also used as a determination criterion.
[0019]
Next, the operation of the identification apparatus configured as described above will be described with reference to FIG.
As described above, FIG. 3A is a diagram showing the groove shape of the optical disk, which is modulated in the depth direction. Now, as shown in FIG. 3B, the light quantity signal detected by the pick-up means 17 is modulated in a concavo-convex shape corresponding to the barcode shape, and is also modulated in the depth direction of the concave portion. . This light quantity signal is branched into two, and one is input to the bar code identification means 25 side. That is, this branch signal is input to the bar code comparator 24 via the amplifier 22 and the limiter 23, where it is compared with the bar code reference value Vt, and as shown in FIG. To be made. The binarized signal is input to the barcode decoder 25, and the corresponding barcode data is obtained by decoding, and is output to the determination unit 31. In FIG. 3, r _n Indicates the output obtained from the conventional groove, r _m Is obtained from the groove of the present invention.
Output to be displayed.
[0020]
On the other hand, the other branched signal is input to the detector 27 via the amplifier 26, where, for example, average value detection is performed, and a sinusoidal modulation signal as indicated by the solid line Vm in FIG. Is demodulated. By cutting the DC component of this signal through the capacitor 28, only the AC component is taken out and further converted into a substantially DC signal through the low-pass filter 29 as shown in FIG. Next, the output of the low-pass filter 29 is input to the amplitude comparator 30, and is compared with the modulation reference value Vtm to be binarized. Then, the result signal is input to the determination unit 31 to determine whether the optical disk is correct.
In this determination, only when the input signal of the previous barcode data decoder 25 indicates the predetermined ID information and the input signal from the amplitude comparator 30 indicates that there is modulation, that is, the first information and the first information. Only when both pieces of information 2 indicate that the optical disc is a regular optical disc, the judging means 31 judges that the disc is a legitimate product, and then executes a reproduction operation.
[0021]
Further, when the determination unit 31 determines that at least one of the first information and the second information is not a genuine product but an unauthorized product, the fact is sent to the reproduction control unit 19. For example, the reproduction operation is stopped and the reproduction is rejected by ejecting the optical disk.
For example, when a bar code-like groove is formed on an illegal copy disc but is not modulated in the depth direction, that is, the first information exists but the second information does not exist Therefore, the output waveform of the detector 27 becomes a substantially DC signal having no modulation signal component as indicated by Vn in FIG. 3D, and therefore the output of the low-pass filter 29 has an AC component in the input signal. Therefore, the output is substantially zero volts as indicated by Vn in FIG. Therefore, if a substantially intermediate value Vtm between Vn and Vm is set as the modulation reference value of the amplitude comparator 30, whether the groove is modulated in the depth direction, that is, whether the second information exists. It can be determined whether or not.
[0022]
In addition, since the optical disc has the second information obtained by modulating not only the first information obtained by arranging the grooves in a bar code shape but also the groove in the depth direction, This duplication becomes very difficult.
In this embodiment, the case where a sine wave is used as the modulation signal has been described as an example. However, the present invention is not limited to this. For example, a digital signal may be used. For example, when a digital signal is used as the modulation signal, two types of groove depths are provided as shown in FIG. 7A, and each groove is arranged in a burst shape. In FIG. The multi-level signal can be recorded by providing three kinds of depths, and therefore, more information can be recorded. Therefore, it is further difficult to manufacture a duplicate disk. Further, in FIG. 7C, there are two types of groove depths, but there are a plurality of types of horizontal lengths. In this case, the difference in lengths has a meaning as data. In addition, a large amount of information can be recorded, and accordingly, it is possible to make the disk copy more difficult.
[0023]
In the above embodiment, the groove depth is modulated. However, the present invention is not limited to this. The groove depth is constant, and the bottom portion is modulated in a wave shape to provide the second information. You may make it have. Hereinafter, this embodiment will be described. The same parts as those described above are denoted by the same reference numerals, and description thereof is omitted.
FIG. 8 is a partially enlarged view showing a conventional optical disk as a second optical disk of the present invention. FIG. 8A is the same as FIG. 2A, and is a partially enlarged view showing a conventional optical disc, and FIG. 8B is a partially enlarged view showing a second optical disc of the present invention. Again, in order to clarify the difference between the two, the conventional optical disk structure is also shown.
In the first optical disc shown in FIG. 2 (B), modulation is applied by changing the depth of the groove 4, but in the second optical disc 1 shown in FIG. The depth of the cord-like groove 4 is made constant, the bottom 32 thereof, in the figure, the upper part of the groove is formed in a wave shape, and second information is added thereto.
[0024]
Such a second optical disk 1 can be easily formed by the groove forming apparatus shown in FIG. The waveforms of the respective parts at this time are shown in FIG. 10, FIG. 10A shows the same barcode data as FIG. 5A, and FIG. 10B shows the modulation output from the modulation signal generator 12. The signal waveform is shown. This modulated signal is not a waveform having a low frequency as shown in FIG. 5B, but a sine wave having a frequency considerably higher than the transfer rate of the barcode data.
Therefore, in the modulated laser beam L2, the signal corresponding to the groove has a wave shape as shown in FIG. As shown in FIG. 10D, the depth of the groove formed by the laser beam L2 is substantially constant, and the bottom 32 is modulated in a wave shape.
[0025]
Next, an identification device for identifying whether the second optical disk is correct or not will be described. FIG. 11 is a block diagram showing a second identification device of the present invention, which is provided in the disk reproducing device 14 in the same manner as the first device, and also includes some components such as pickup means and tracking. The error detection means is also used. Further, the barcode identifying means 25 for obtaining the first information by decoding the barcode data from the groove 4 of the optical disk is the same as the first apparatus.
In order to obtain the second information, the output of the pickup means 17 is branched and connected to the tracking error detection means 33, where a tracking error signal is obtained. The obtained tracking error signal is branched, and one is input to a servo circuit (not shown) of the reproduction control means 19 for tracking control. The other is connected to the crossover comparator 34, where it is converted to a binary signal by comparing with the reference value Vo. The output of the comparator 34 is connected to a track crossing counter 35 as zero cross counting means, and measures the number of track crossings. This output result is input to the microprocessor 37, where the zero cross number measured within a predetermined period and the predetermined reference value are compared by the zero cross count value comparing means 38. This comparison result is input to the determination means 39, and it is determined whether or not this optical disc is a genuine product.
[0026]
Here, the operations of the zero cross count value comparing means 38 and the judging means 39 are processed by software in the microprocessor 37. A predetermined period for measuring the number of zero crosses is counted by the timer means 40 connected to the microprocessor 37. Further, the reference value of the zero cross count value comparing means 38 is preliminarily stored in the track crossing setting unit 41 such as a ROM. Set it.
[0027]
Next, the operation of the identification apparatus configured as described above will be described with reference to the diagram shown in FIG. In FIG. 9, the left half of the figure shows the conventional groove shape and the corresponding waveform, and the right half of the figure shows the groove shape of the second optical disc of the present invention and the corresponding waveform. Indicates. 9A shows the conventional groove shape and the groove shape of the disk of the present invention, and the bottom 32 of the groove of the disk of the present invention is wave-shaped and modulated as described above.
The tracking error signal detected by the pick-up means 17 is introduced to the comparator 34 via the tracking error detection means 33, where it is compared with the reference value, and the zero-crossed signal is binarized. This output signal is input to the track crossing counter 35 and the number of crossings is measured. The number of crossings at this time is measured in units of a predetermined time, and the time management is performed based on the output signal from the timer means 40. The output of the counter 35 is input to the zero cross count value comparing means 38 of the microprocessor 37, and this is compared with the reference value of the track crossing number, and the result is introduced to the judging means 39 to judge whether the disk is correct or not. To do.
[0028]
Here, the tracking error signal output from the tracking error detection means 33 is as shown in FIG. 8B. In the case of a groove formed by penetrating the aluminum layer as in the conventional case, as shown in the left half. An irregular tracking error occurs only at the portion corresponding to the edge of the slot, and the tracking error is almost zero because the central portion of the slot has a very low light reflectance. On the other hand, in the case of the groove of the disk of the present invention, the bottom of the groove is wavy, so that a large number of tracking error zero crosses occur as shown in the right half of FIG. Therefore, the zero-cross count value per predetermined unit time (period) C1 is much larger in the right half count value V2 than in the left half count value V1. In the figure, V1 and V2 are both expressed as voltage conversion values for the sake of schematic explanation, but they are actually digital counter values. Therefore, by comparing this count value with a predetermined reference value (track crossing setting value) Vs located between V1 and V2, it is possible to determine whether the optical disc is a genuine product or an unauthorized product. .
[0029]
Also in this case, as a matter of course, determination is made on the barcode identification means 25 side as to whether or not the barcode indicates a disc-specific ID number. Only when the bar code indicates the ID number unique to the disk and the modulation signal at the bottom of the groove is detected, it is recognized as a genuine product and the disk is reproduced.
If at least one of the conditions is not satisfied, the disc is recognized as an illegal illegal copy disc, the reproduction operation is stopped, and the disc is ejected.
Also in this disk, not only is the groove provided in a bar code shape to give the first information but also the groove bottom is modulated in a wave shape to give the second information. This can contribute to prevention of unauthorized copying.
In each of the above embodiments, a compact disk has been described as an example. However, the present invention is not limited to this, and can be applied to a mini disk, a double-sided bonded MO disk, a DVD-ROM, or the like. .
[0030]
【The invention's effect】
As described above, according to the optical disc and the identification device of the present invention, the following excellent operational effects can be exhibited.
Since the groove is arranged in a bar code shape to give the first information, and the groove itself is given the second information by modulating the depth direction or the groove bottom, it takes a lot of time for the analysis. Equipment is required, and as a result, it is very difficult to manufacture an illegal duplicate disk.
Further, since the components used in the optical disc identification device are originally essential as a reproduction circuit, they are built in a commercially available LSI and can be provided at low cost without much assembling cost.
Furthermore, since the barcode pattern and its modulation frequency are not so high and low, the read data transfer rate is much lower than the disk data transfer rate, so the read data is read directly by the software by a microprocessor or the like. This is cost effective because it does not require hardware for data interpretation.
[Brief description of the drawings]
FIG. 1 is a plan view showing an optical disc.
FIG. 2 is a partially enlarged view showing a conventional optical disc and a first optical disc of the present invention.
FIG. 3 is a diagram showing the shape of a groove and the corresponding waveform of each part of the apparatus in FIG. 6;
FIG. 4 is a schematic configuration diagram showing a groove forming apparatus for forming the groove of the optical disk described above.
FIG. 5 is a diagram showing a waveform of each part when a groove is formed.
FIG. 6 is a block diagram showing a first identification device of the present invention.
FIG. 7 is a diagram showing a modification of the modulation mode of the groove.
FIG. 8 is a partially enlarged view showing a conventional optical disc and a second optical disc of the present invention.
FIG. 9 is a diagram showing a conventional groove, a groove shape of the present invention, and waveforms of respective parts corresponding thereto.
FIG. 10 is a diagram showing a waveform of each part when a groove is formed.
FIG. 11 is a block diagram showing a second identification device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Optical disk, 4 ... Groove on barcode, 5 ... Identification area | region, 7 ... Disc base, 8 ... Aluminum layer, 17 ... Pick-up means, 20 ... Identification apparatus, 21 ... Reflected light quantity detection means, 25 ... Barcode identification means , 27 ... detector (amplitude detection means), 30 ... amplitude comparator (amplitude comparison means), 31 ... judgment means, 32 ... bottom of the groove, 33 ... tracking error detection means, 34 ... crossing comparator, 35 ... track crossing counter ( Zero cross count means), 38... Zero cross count value comparison means, 39.

Claims (5)

In an optical disk in which a groove corresponding to a bar code is formed after manufacturing the disk, the shape of the groove is modulated at a predetermined frequency in the depth direction, and first information by the groove corresponding to the bar code, An optical disc comprising second information by shape modulation. In an optical disk in which a groove corresponding to a barcode is formed after manufacturing the disk, the bottom of the groove is modulated in a wave shape. First information by the groove corresponding to the barcode and a first information by a wave modulation of the bottom of the groove. 2. An optical disc characterized by having information of 2. 2. An identification apparatus for identifying an optical disk as defined in claim 1, wherein a pickup means for optically detecting the groove, a reflected light quantity detection means for detecting a reflected light quantity obtained by the pickup means, and an amplitude of the reflected light quantity are detected. An amplitude detecting means for comparing the output signal from the amplitude detecting means with a predetermined reference value, and a judging means for judging whether the optical disk is correct based on the comparison result of the comparing means. An optical disc identification device. 3. An identification apparatus for identifying an optical disk as defined in claim 2, wherein a pickup means for optically detecting the groove, a tracking error detection means for detecting a tracking error signal from an output of the pickup means, and a zero cross of the tracking error signal Zero cross counting means for counting, timer means for measuring the detection time of the tracking error signal, and zero cross count value for comparing a predetermined reference value with the number of zero crosses measured within a predetermined period measured by the timer means An optical disc identification apparatus comprising: comparing means; and judging means for judging whether the optical disk is correct or not based on a comparison result of the comparing means. 4. The apparatus according to claim 3, further comprising: a barcode identification unit that recognizes the barcode from an output signal of the pickup unit, wherein the determination unit determines whether the optical disc is correct based on the identified barcode. 4. An optical disc identification device according to 4.

Images