JP2000011536A - Disk type recording medium with duplication prohibiting function and its reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk type recording medium with duplication prohibiting function and its reproducing device which can prohibit duplication using an error added previously and intentionally. SOLUTION: Before data are recorded in a disk 1, a correctable error is added to the data at a fixed period previously and intentionally. When an error added previously at a fixed error is detected, outputting to a duplication recording device 9 from this disk 1 is provided so that duplication data from the disk 1 is made disable. A period of an error is made a period being different from a rotation period of the disk 1 to distinguish the intentional error from an error caused by scratch and the like. Also, a part on the disk from which output is limitted, is selected in accordance with a region to which an error is added. Also, plural error-added patterns of the disk 1 are prepared so that an output limit mode is selected in accordance with a detected pattern. Also, output is limitted in accordance with whether a set data has elapsed or not. Further, output is limitted in accordance with an output region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk with a copy inhibiting function and a reproducing apparatus for the same. In particular, the present invention relates to a disk-shaped recording medium with a copy prohibition function for adding a correctable error in advance at the time of data recording, detecting the error, and prohibiting duplication, and a reproducing apparatus therefor.

[0002]

2. Description of the Related Art A description will be given of a CD as an example. When data is recorded on a CD, an error correction operation is performed by CIRC to encode the data. That can be restored. FIG. 1 shows an outline of a system for restoring and reproducing data encoded and recorded on a disc by performing an error correction operation by the CIRC even if the disc is damaged. In FIG. 1, recording data is encoded by performing an error correction operation by CIRC (S1), EFM-modulated (S2), and recorded on a disk (S3). In reproduction, the data recorded on the disk is read by the optical head (S4), and EFM demodulated (S5). Next, the data is reproduced by performing an error correction operation by the CIRC (S6), and becomes reproduced data. And
Even if the disc is damaged, the recorded data and the reproduced data are the same data.

[0003]

Recently, the quality of reproduced output has been improved, and it is now possible to obtain a high-quality copy by recording the recorded data. On the other hand, it is also necessary to prohibit copying because of copyright.
Conventionally, in order to obtain a high correction capability, CIRC is employed when encoding and recording data on a CD. But,
Recently, the quality of the manufacturing apparatus has been improved, and it is less likely that dust and bubbles are mixed in the disk manufacturing process to lower the data quality. In addition, the tracing capability of the reproducing apparatus has been increased, and the influence of scratches, dust, etc. on the disc has been reduced. As a result, since the correction capability has been increased, it is possible to intentionally add a correctable error at the time of reproduction at the time of encoding.

Accordingly, an object of the present invention is to provide a disk-shaped recording medium with a copy prohibition function and a reproducing apparatus for the same, which can surely and easily prohibit duplication by using an error which is intentionally added in advance. .

[0005]

In order to solve the above-mentioned problems, according to the present invention, when data is recorded on a disk, a correctable error is added in advance at a fixed period. Then, if an error is added in advance at a fixed cycle and an error is detected, output from the disk is restricted by, for example, prohibiting the data from being copied from the disk. The period of this error is made different from the rotation period of the disk so that it can be distinguished from errors due to scratches and the like. Further, it is possible to select a portion for restricting the output on the disk according to the area to which the error has been added. Further, a plurality of additional error patterns of the disk are prepared, and the output restriction mode can be selected according to the detected pattern. Also, the output can be limited according to whether or not the set date has passed. Further, the output can be limited according to the region where the product is shipped.

[0006]

FIG. 2 is a diagram showing a configuration of an error correction system for performing encoding and decoding by performing an error correction operation by CIRC. In FIG. B, (a) shows a system configuration of a CIRC recording system that performs an error correction operation by the CIRC when recording digital data on a disk and encodes the data.
Bits x 12 symbols become one unit and C
Enter the IRC recording system. Then, delay scrambling of two symbols is performed (S11), and rearrangement is performed to obtain 8 bits × 24 symbols. Thereafter, C2 encoding is performed (S12), and a code for error correction of 4 symbols is added. This gives a data length of 28 symbols.
Subsequently, the data sequence is sent to the interleave (S13), the C1 encoding is performed on the interleaved data sequence (S14), and a code for error correction of 4 symbols is added. Thus, the data length becomes 32 symbols. Thereafter, delay scrambling of one symbol is performed (S1
5) CIRC encoded data having a length of 32 symbols to be recorded is obtained. This data is arranged one bit at a time, and the data is output in series. Synchronous addition, EFM modulation and the like are performed and the data is recorded on a disk.

According to the present invention, when recording CIRC encoded data on a disc in order to add an error used for duplication prohibition in advance, one frame as an error correction unit, that is, one bit in 8 bits × 32 symbols. Only the bit is inverted. As a result, an error is artificially added (S16). FIG. 2B shows a configuration of a CIRC reproduction system that reproduces digital data recorded on a disk by performing an error correction operation using the CIRC and decoding and reproducing the data. Decoding may be performed in the reverse of encoding. The data read from the disk is one frame worth after synchronous processing and EFM demodulation.
Bits × 32 symbols are input in parallel, and a one-symbol delay descrambling is first performed (S21), and a one-symbol delay scrambled signal at the time of recording is canceled. Next, C1 decoding is performed (S22), and the data length becomes 28 symbols. Next, it is sent to the deinterleave (S2
3) C2 decoding is performed on the deinterleaved data sequence (S24), resulting in 8 bits × 24 symbols. Then, two-symbol delay descrambling is performed (S25), and rearrangement is performed to obtain 16 bits × 12 symbols. When this is applied to a D / A converter, a sound comes out.

In the reproducing system shown in FIG.
Is an erasure flag. When C1 decoding and C2 decoding are performed, there is an error correction, and when the correction is performed, the fact is output. By monitoring the erasure flag, it is possible to detect whether an error has occurred. The erasure flag is output in the same manner in the case of an error due to a scratch or the like generated at the time of recording and in the case of the added error, and it is impossible to identify both.

FIG. 3 is a diagram showing how an error is added to a disc in the present invention in order to identify both. The error to be added needs to have the following conditions. First, it must be correctable. For that purpose, it is necessary to minimize the amount of error to be added. Next, it is necessary to be able to identify the scratches and dust that the user has made during use. Signal errors due to scratches or dust applied by the user often occur in accordance with the rotation cycle of the disk. For example, if the scratch is made in a straight line in the radial direction of the disc, one revolution of the disc makes one revolution.
Missing signals occur at the rate of the number of times. Therefore, for example, if an error is added in a cycle shorter than the shortest rotation cycle of the disk, it is possible to distinguish between a signal error due to scratches and dust and the added error.

In FIG. 3, a spiral line represents a track of a CD, and e represents an added error. Since a CD is recorded at a constant linear velocity (CLV), the recording density on the circumference of the disc is constant. Therefore, if the rotation period, which is the time required for the disk to make one revolution, is t, the linear velocity is v, and the radius of the track at that time is r, t = 2πr / v. In this equation, since v is constant, when r is small, that is, when the signal of the track inside the disk is being reproduced, the rotation period becomes small. According to the CD standard, the radius r of the innermost disk
_min = 46 mm (46 × 10 ⁻³ m), linear velocity v = 1.2
１1.4 m / s. Accordingly, the innermost rotation period t _min = 2π × 46 × 10 ⁻³ /1.4=2.06×1
0 ⁻¹ s. Therefore, if an error is added at a cycle shorter than 2.06 × 10 ⁻¹ s, which is the shortest rotation cycle of the disk, it is possible to identify a signal error due to scratches or dust. On the other hand, since the unit for performing error correction is one frame, if an error is added in a cycle of a frame number smaller than the number of frames included in 2.06 × 10 ^-1 s, which is the shortest rotation cycle of the disc, damage is caused. Signal errors due to dust and dust can be identified.

Since the length t _f = 1/75 s of one frame, which is a unit for performing error correction, the number of blocks included in 2.06 × 10 ⁻¹ s, which is the shortest rotation cycle of the disk, is 2. 06 × 10 ⁻¹ s ÷ 1/75 s = 15.45 frames. Therefore, if an error is added at a cycle of 15.45 frames or less, for example, once every 14 frames, it can be identified as an error caused by scratches or dust applied by the user during use.

FIG. 4 is a diagram showing how an error due to a scratch or dust and an added error are identified in frame units. (A) shows a waveform of an FG signal which generates a pulse each time the disk makes one rotation. (B)
Indicates a frame in which an erasure flag is detected, that is, a frame in which an erasure flag is detected. ing. In this case, a frame in which an error added in advance according to the present invention has been corrected is not included, and only a frame in which an error due to a flaw or the like has been corrected is detected in each rotation cycle T. (C) shows a frame in which an erasure flag, which is also an error correction signal of the disk, is detected, and “○” means a frame without error correction,
“X” means a frame in which an error due to a scratch or the like has been corrected. The difference from (b) is that a frame “△” in which an error intentionally added in advance according to the present invention is corrected is included. This error correction frame “△” is detected every additional error period Te shorter than the rotation period, for example, once every 14 frames, so that it can be identified as an error correction frame due to a flaw detected at each rotation period. It has become.

In FIGS. 3 and 4, a disk having a constant linear velocity has been described as an example. However, even if the linear velocity is not constant, an error may be added so that the disk can be detected at a constant period. FIG. 5 is a diagram showing an outline of an embodiment of a disc reproducing apparatus according to the present invention, which can detect an added error in a disc and control the output.
1 is an optical disk on which data is recorded, and 2 is a disk motor for rotating the optical disk 1. Reference numeral 3 denotes an optical pickup unit for reading a signal from the optical disk 1, which includes a laser diode and a focus actuator, and a tracking actuator and a condenser lens. Reference numeral 4 denotes a servo signal processing circuit, which is a focus servo that focuses on the signal surface of the optical disk, a tracking servo that tracks a signal track, a thread servo that sends a pickup according to the diameter of a signal reading area, and a spindle that controls a signal reading linear velocity. Control the servo. Reference numeral 5 denotes a digital signal processing circuit, which includes a PLL circuit for synchronizing a clock with a read signal at the time of data extraction, a decoder for decoding the extracted signal, and a circuit for deinterleaving the decoded signal and correcting errors. Reference numeral 6 denotes an amplifier for amplifying a signal from the digital signal processing circuit 5, and the amplified signal is output from a speaker 7. Reference numeral 8 denotes an output control circuit for controlling the output of the digital signal processing circuit according to the present invention, which is connected to the duplication recording device 9. It should be noted that the duplication recording device 9 may be integrated with the optical disk reproducing device, or may be separate. Reference numeral 10 denotes a control unit constituted by a microcomputer or the like, which controls the servo signal processing circuit 4 and the digital signal processing circuit 5, monitors an erasure flag fe output from the digital signal processing circuit 5, and outputs an output control circuit 6 based on the result. Control. That is, the erasure flag fe
Is monitored and its cycle is measured, and the erasure flag fe
If it is determined that the added error is included from the cycle of, the disk is determined to be a copy prohibited disk and the output of the output control circuit 8 is stopped. The output control circuit 8 can not only stop the output but also limit the output by stopping a part of the signal output.

FIG. 6 is a diagram showing a pattern of an added error according to the present invention. It has been described that if an error is added at a cycle of 15.45 frames or less, an error caused by scratches or dust applied by a user during use and an added error can be identified. FIG. 6 shows disk data in units of 15 frames. In the figure, as described above, “○” means a frame without error correction, and “×”
Indicates a frame in which an error due to a scratch or the like has been corrected. “△” indicates a frame in which an error added in advance according to the present invention has been corrected. The frame “x” in which an error due to a flaw or the like has been corrected is normally detected at the same cycle as the rotation cycle. On the other hand, in this example, the frame “Δ” in which the added error has been corrected is detected once in 14 blocks, which is a cycle shorter than the rotation cycle, and detected in a cycle shorter than the rotation cycle. Therefore, an error correction frame “x” having the same cycle as the rotation cycle is determined to be an error correction frame due to a scratch or the like,
If an error correction frame is detected at a different cycle from the rotation cycle and at a constant interval, the disc is determined to be a copy-prohibited disc. Note that the FG signal of the disk motor 2 is used to detect the rotation cycle. F
If there is no G signal, the rotation period can be calculated by jumping several tracks, and by the time difference between the two subcode information.

FIG. 7 is a flowchart showing the control operation for determining whether the disk is a copy-prohibited disk. The control of this flowchart is performed by the control unit 10 shown in FIG.
Done by In FIG. 7, when the control is started, for example, the cycle of the FG signal, that is, the rotation cycle T of the disk is measured (S1). Next, an error correction signal, that is, an erasure flag is detected, and the cycle of this signal is measured (S2). The error correction signal alone cannot identify whether the error is due to a scratch or an added error. Therefore, a signal having a cycle different from the rotation cycle T of the disk is taken out of the error correction signal (S3), and it is determined whether or not the cycle is a fixed cycle (S3).
4). If it is a fixed cycle (Yes), it is determined whether this cycle is shorter than the rotation cycle (S5). If Yes, the disc is determined to be copy-prohibited, and the output is restricted by prohibiting output (S6). S4
Or, if No in S5, the output is not stopped.

In the case of error correction due to scratches, the detected signal often has almost the same rotation period. Therefore, since the detected fixed cycle may be different from the rotation cycle, it is not determined whether or not the rotation cycle is shorter than the rotation cycle, that is, the determination in S5 of FIG. 7 is not performed. If the period is constant (S4), the output may be limited by judging that copying is prohibited.

In the case of the flowchart shown in FIG. 7, when an added error is detected, the output is limited. According to the present invention, which signal is output according to the area on the disk to which the error has been added. Can be selected. FIG. 8 shows a flowchart in such a case. In this flowchart, S1 to S4 are the same as those in the flowchart of FIG. In this flowchart, if it is determined in S4 that the period is a fixed period (Yes), an error-added area on the disk is detected (S5). For example, when it is detected that an error is added only to a certain track No., output of only the track No. is prohibited (S6), and when an error is added to the lead-in area of the disc, The output of the entire disk is prohibited (S7). Further, it is possible to prohibit the output only in the area where the error is added (S8). In this way, the output restricted areas A, B, C, and the like can be selected depending on which part of the disk is to be restricted in output.

In the case of the flowchart shown in FIG. 8, a signal for inhibiting the output can be selected according to the area on the disk to which the error has been added. According to the present invention, the pattern of the error to be added can be selected. By changing, a plurality of output restriction modes corresponding to the pattern can be obtained. FIG. 9 shows a flowchart in such a case. In this flowchart, S1 to S4 are the same as those in the flowchart of FIG. In this flowchart, if it is determined in S4 that the period is a fixed period (Yes), an added error pattern is detected (S5). When the pattern A is detected, the output restriction mode A is selected (S6). For example, if the output signal is a voice signal, the output of the digital signal is prohibited. This makes it impossible to duplicate the digital output of the audio. When the pattern B is detected, the output restriction mode B is selected (S7). For example, when the output signal is an audio signal, the output of both the digital signal and the analog signal is prohibited. This makes it possible to prevent the digital output and the analog output of the sound from being duplicated. Therefore, in this case, it is possible to perform reproduction with a speaker built in the disk reproducing device. If another pattern is detected, the output restriction mode C is selected (S
8).

Although the above-described output restriction mode has been described with respect to audio as an example, when the output is video and audio, for example, only video or audio output can be prohibited according to the added error pattern. . FIG. 10 is a diagram showing a different pattern of the added error from FIG. FIG. 10 shows the error correction signal in units of 15 frames as in FIG. In the figure, as described above, “○” means a frame without error correction, and “×”
Indicates a frame in which an error due to a scratch or the like has been corrected. “△” indicates a frame in which an error added in advance according to the present invention has been corrected. In the upper frame of the figure, a pattern (referred to as a pattern A) in which a frame “Δ” in which an error added in advance according to the present invention is corrected is detected twice in 15 frames. Also,
In the lower block of this figure, a pattern (referred to as pattern B) in which a frame “Δ” in which an error added in advance according to the present invention is corrected is detected three times in 15 frames. By detecting such patterns A and B, the output restriction modes A, B and C according to these patterns can be selected.

According to the present invention, the output from the disk can be restricted based on the date set on the disk. For example, a date may be set in advance according to an error pattern to be added, and output may be prohibited so that copying cannot be performed until the date has passed. FIG.
Reference numeral 1 denotes a flowchart when a date is set, and output prohibition or release can be performed based on the date. In this flowchart, S
Steps 1 to S4 are the same as those in the flowchart of FIG.
In this flowchart, if it is determined in S4 that the cycle is a fixed cycle (Yes), the current date is detected from the calendar function built in the disc reproducing apparatus (S5).
Next, the set date is detected from the additional error pattern (S
6). If the detected date is before the date set on the disc (Yes), the output is limited. However, if the date is after the set date (No), the output is not restricted and copying can be performed. In this way, by limiting the output according to the due date, for example, in the case of a music CD, the output can be prohibited and a copy cannot be made until a predetermined period elapses from the release. Conversely, in S7 of FIG.
The output can be prohibited after elapse of the set date by reversing s and No.

Although FIG. 11 shows that duplication can be prohibited according to the due date, it is also possible to restrict output, for example, to prohibit duplication depending on the country of shipment. FIG.
Shows a flowchart in the case where the country or region where the product is shipped is identified, and output prohibition or release can be performed according to the country or region. In this flowchart, S1 to S4 are the same as those in the flowchart of FIG. In this flowchart, if it is determined in S4 that the period is a fixed period (Yes), the shipping country or region stored in the memory of the disk reproducing device is identified (S5). If the identified country or region is a country or region for which copying is prohibited, the output is prohibited in (Yes). But if not (No)
The output is not prohibited and can be duplicated.

Although the present invention has been described with reference to a CD as an example, a disc in the present invention is not limited to a CD, but may be a DVD, M
Needless to say, D, MO, etc. are also included.

[0023]

As described above, according to the present invention, duplication of data on a disk can be simply and reliably inhibited by adding a correctable error in a fixed cycle in advance. At this time, data on the disk whose duplication is prohibited can be selected by the error addition area. The output inhibition mode can be selected by changing the pattern of the error to be added. In addition, by setting a date, duplication before or after the date can be prohibited. Furthermore, by identifying a country or region, copying in a specific country or region can be prohibited.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of a system for performing an error correction operation by a CIRC and restoring and reproducing data encoded and recorded on a disk even when there is an error.

FIG. 2 is a diagram showing a configuration of an error correction system that performs an error correction operation by CIRC to perform encoding and decoding.

FIG. 3 is a diagram showing how an error is added in the present invention.

FIG. 4 is a diagram illustrating how an error due to a scratch or dust and an added error are identified in frame units.

FIG. 5 is a diagram showing an outline of an embodiment of a disk reproducing apparatus according to the present invention, which can detect an added error in a disk and limit the output.

FIG. 6 is a diagram showing a pattern of an error intentionally added.

FIG. 7 is a flowchart showing an operation of control for determining whether the disk is a copy-prohibited disk.

FIG. 8 is a flowchart showing a control operation when a signal for inhibiting output is selected according to an area on a disk to which an error has been added.

FIG. 9 is a flowchart showing a control operation when changing a pattern of an error to be added to obtain a plurality of output inhibition modes corresponding to the pattern.

FIG. 10 is a diagram showing another pattern of an intentionally added error.

FIG. 11 is a flowchart showing an operation of control when a date is designated and output can be prohibited or released based on the date.

FIG. 12 is a flowchart showing a control operation in a case where a country, a region, and the like are identified, and output can be prohibited or released based on the result.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical disk 2 ... Disk motor 3 ... Optical pick-up unit 4 ... Servo signal circuit 5 ... Digital signal processing circuit 6 ... Amplifier 7 ... Speaker 8 ... Output control circuit 9 ... Copying recording device 10 ... Control part

Claims (10)

[Claims] 1. A disk-shaped recording medium intentionally added in advance so that a correctable error can be detected at a fixed period during data recording. 2. The disk-shaped recording medium according to claim 1, wherein the period is shorter than a rotation period of the disk. 3. The disk-shaped recording medium according to claim 1, wherein the error is added to a specific area of the disk. 4. The disk-shaped recording medium according to claim 1, wherein the added error has a plurality of patterns that can be selected for each disk to which the error is added. 5. An error correction signal detecting means for detecting a signal indicating that error correction of a disk error has been performed, a means for extracting a signal having a cycle different from the rotation cycle of the disk from the detected signal, Means for judging whether or not the read signal has a fixed period, signal processing means for processing and outputting a signal read from a disk, and controlling the output of the signal processing means when outputting the output to the duplication recording means. A disc reproducing apparatus comprising: output control means; and means for controlling the output control means so as to limit the output from the signal processing means when the extracted signal has a fixed period. 6. The apparatus according to claim 5, further comprising means for judging whether a cycle of the extracted signal is shorter than a rotation cycle of the disk, and when the cycle is shorter, the output control means limits an output from the signal processing means. A disk playback device according to claim 1. 7. A means for detecting an error-added area of the disk which has caused the extracted signal, and the output control means limits an output on the disk according to the detected error-added area. 6. The disc reproducing device according to claim 5, wherein the portion is selected. 8. The disk reproducing apparatus according to claim 5, further comprising means for detecting an additional error pattern of the disk, wherein said output control means selects an output restriction mode according to the detected pattern. 9. An output control method according to claim 9, further comprising: means for detecting an additional error pattern of the disc; and means for identifying a preset date from the detected pattern. 6. The disc reproducing apparatus according to claim 5, wherein the means limits an output. 10. shipping area data stored in a memory;
6. The disc reproducing apparatus according to claim 5, further comprising: shipping area identification means for identifying a shipping area from the data, wherein the output control means limits an output according to the identified area.