KR100656687B1 - Optical disc recording apparatus, optical disc recording method, optical disc and optical disc reproducing apparatus - Google Patents

Abstract

The present invention relates to an optical disc recording apparatus, an optical disc recording method, and an optical disc. For example, the present invention is applied to a compact disc creator, a compact disc, and a compact disc player without affecting the reproduction of a main data string by a pit array or the like. By recording the sub data strings so that the main data strings can be reproduced by the optical pickup which reproduces the main data strings, and which are difficult to copy by the illegal copying, the pits and marks at timings that do not affect the positional information of the edges are recorded. The sub data string ED is recorded by locally changing the reflecting film of the back.

Main data stream, pit, land, information recording surface, light beam, sub data stream, repeat recording

Description

Optical disk recording apparatus and method, and optical disk             

1 is a block diagram showing an apparatus for completing a compact disc according to a first embodiment of the present invention.

FIG. 2 is a sectional view and a timing diagram provided in the description of a compact disc completed in the completion apparatus of FIG. 1; FIG.

3 is a timing diagram provided to explain the operation of the completion device of FIG. 1;

4 is a block diagram showing a modulation circuit of the completion device of FIG.

Fig. 5 is a block diagram showing a compact disc player for playing back the compact disc created by the completion device of Fig. 1;

6 is a block diagram showing a disc identification code reproducing circuit of the compact disc player of FIG.

7 is a block diagram showing an apparatus for completing a compact disc according to a second embodiment of the present invention.

FIG. 8 is a block diagram illustrating a 9T abnormal pattern detection circuit of the completion device of FIG. 7. FIG.

FIG. 9 is a block diagram illustrating a 9T or more pattern prediction circuit of the completion device of FIG. 7. FIG.

10 is a block diagram showing an apparatus for completing a compact disc according to a third embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

1: compact disc 2: disc board

3: reflective recording surface 4: protective film

10, 60, 80: completion device 13, 83A, 83B: optical pickup

14: APC circuit 18, 41, 70: sync pattern detection circuit

19, 71: Sync pattern prediction circuit 20: Disc identification code generation circuit

20A, 51, 69: sub code detection circuit 21, 75: modulation circuit

30: compact disc player 41: disc identification code reproduction circuit

62: 9T abnormal pattern detection circuit 63: 9T abnormal pattern prediction circuit

The present invention relates to an optical disc recording apparatus, an optical disc recording method and an optical disc, and can be applied to, for example, a compact disc producing apparatus, a compact disc, and a compact disc player. According to the present invention, a disc in which information is recorded as a pit row in advance can be reproduced by an optical pickup which reproduces the main data stream without affecting the reproduction of the main data stream by the pit row or the like by locally changing the reflection film. In addition, it is also possible to record a sub data string, making it difficult to copy by illegal copying.

(Conventional technology)

Conventionally, in a compact disc, data processing of a data string provided for recording is performed, followed by EFM modulation (Eight to Fourteen Modu1ation), whereby a pit string of periods 3T to 11T is formed for a predetermined basic period T, whereby audio Data and the like are recorded.

In contrast, a recording area for management data is formed in the lead-in area on the inner circumferential side, and a desired performance or the like can be selectively reproduced by the TOC (Table Of Contents) recorded in this recording area.

In this way, a compact disc having various data recorded thereon is marked with a code indicating a manufacturer, a place of manufacture, a disc number, etc. on the inner circumferential side of the lead-in area, whereby the history of the compact disc can be visually confirmed. It is supposed to be.

By the way, it is thought that the illegal copy can be identified by the presence or absence of this marking by being able to confirm the history of a compact disc in such marking. However, this mark has a drawback that it is difficult to reproduce by optical pickup of a compact disc player for the purpose of visual confirmation. As a result, when the illegal copy is identified by the marking, a dedicated reproducing mechanism is necessary separately in order to reproduce the marking.

In addition, the codes recorded by these methods are recorded by the same method as a normal pit, so that the protective film and the aluminum reflective film of the compact disk can be peeled off to create a stamper, thereby causing a problem of illegal copying.

Thereby, it has no effect on the reproduction of the audio data by the pit rows, and if the sub information can be recorded by the optical pickup which reproduces the audio data and it is difficult to copy by the illegal copying, this sub It is believed that the information can be used to rule out illegal copying.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has no effect on reproduction of data by pit rows or the like, and can be reproduced by optical pickup for reproducing data by pit rows or the like and copied by illegal copying. It is difficult to propose an optical disk recording apparatus capable of recording sub data strings, an optical disk recording method, and an optical disk created thereby.

In the present invention for solving such a problem, in the optical disk recording apparatus and the optical disk recording method, the pit is repeated on the information recording surface, and the information recording surface is irradiated with a light beam to the disk-type recording medium on which the main data string is recorded. The sub data string is recorded by changing the reflectance.

Further, in the optical disk, the reflectance of the information recording surface changes with respect to the pits and / or lands so that the sub data string is recorded.

The sub data recorded as the reflectance change of the information recording surface on the disc-shaped recording medium on which information is recorded in an uneven state such as a pit is difficult to copy by a method of peeling off the reflecting film to create a stamper. This makes it possible to record sub data strings by making illegal copying difficult. In addition, the sub data recorded in this way can be set so that the amount of change in reflectance caused by the sub data is small, so as not to disturb the reproduction of the main data. In addition, the sub data recorded as the change in the reflectance can be detected and decoded as the change in the reproduction signal by the optical pickup.

In the present invention, one bit of sub data can be recorded over a plurality of pits and lands. It is also possible to change the reflectance of the information recording surface locally at a point separated by a predetermined distance from the edge. When the present invention is constituted as described above, the reflectance can be changed more locally without affecting the timing of the edge. As a result, the sub data string recorded by the change in the larger reflectance can reproduce the sub data string with higher stability.

As a result, in the optical disc, the pit according to the length of the main data string is repeated on the information recording surface and the main data string is recorded, the pit is recorded as the physical shape change of the information recording surface, and the reflectance of the information recording surface is increased. When the sub data string is changed and recorded, the copy can be effectively excluded.

(Example)

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(1) First embodiment

(1-1) Configuration of First Embodiment

Fig. 2 is a timing diagram showing the format of the compact disc according to this embodiment together with the cross-sectional structure of the compact disc. In this compact disc 1 (FIG. 2D), the disk board | substrate 2 is created by injection molding of polycarbonate etc. which used the stamper like a normal compact disc. In this injection molding, the disk substrate 2 is formed with a fine concavo-convex shape corresponding to the pits and lands on the information recording surface side. In addition, the compact disc 1 is partially enlarged by an arrow a (as shown in Fig. 2E), for example, a reflection which reflects a laser beam on the information recording surface side of the disc substrate 2 by vapor deposition. The recording surface 3 is formed, and then the protective film 4 which protects the reflective recording surface 3 is formed.

As a result, the compact disc 1 is capable of recording an audio signal or the like by repetition of pits and lands as in a conventional compact disc. The compact disc 1 also penetrates the disc substrate 2 and reflects the laser beam L onto the recording surface. By irradiating (3) and receiving the returned light, the audio signal or the like thus recorded can be reproduced.

Here, the repetition of the pits and lands formed in this way is assigned 75 CD frames per second, as in a conventional compact disc (FIG. 2A), and 98 EFM frames are assigned to each CD frame, respectively ( (B) of FIG. 2). In addition, each EFM frame is divided into 588 channel clocks, and frame sync is assigned to the first 22 channel clocks. The pit and the land are repeated in one cycle of the one-channel clock by the length of an integer multiple of the basic period as the basic period T, and are created by the period 11T as the frame sink, respectively.

In addition, in this embodiment, the reflective recording surface 3 is made of the same film structure as the information recording surface of the CD-R. As a result, the compact disc 1 is configured to irreversibly change the reflectance of the reflective recording surface 3 at the laser beam irradiation position when irradiating the laser beam L by a predetermined light amount or more. It is possible to detect the change in the amount of light of the returned light.

Fig. 1 is a block diagram showing the completion device of this compact disc. The compact disc 1 is shipped with the disc identification code recorded by the completion device 10.

That is, in this completion device 10, the spindle motor 11 drives the compact disc 1 to rotate under the conditions of a constant linear velocity under the control of the servo circuit 12. As shown in FIG.

The optical pickup 13 irradiates the compact disc 1 with a laser beam, receives the returned light, and outputs a reproduction signal RF whose signal level changes in accordance with the amount of the returned light. At this time, the optical pickup 13 raises the light amount of the laser beam at a predetermined timing by the control of the APC (Automatic Power Control) circuit 14, whereby the reflective recording surface 3 of the compact disc 1 The reflectance is changed locally.

The amplifier circuit 15 amplifies this reproduced signal RF with a predetermined gain and outputs it. The binarization circuit 16 binarizes the reproduction signal output from the amplifier circuit 15 by a predetermined reference level and outputs the binarization signal BD. The PLL circuit 17 reproduces the channel clock CK from this binarized signal BD.

The sync pattern detection circuit 18 detects a sync pattern repeatedly appearing in the binarized signal BD. That is, in contrast to FIG. 2, as shown in FIGS. 3A-1 to 4-4, the binarized signal BD is switched in signal level corresponding to the pit string formed on the compact disc 1. In the frame sink assigned to the head of each frame, after the period of the period 11T and the signal level rise, the period of the period 11T and the signal level decrease continuously. The sync pattern detection circuit 18 detects this frame sync by determining the continuous signal level of the binarized signal BD with respect to the channel clock CK by means of a flip-flop circuit connected in multiple stages. From the detection result of this frame sync, the sync pattern detection pulse SY at which the signal level rises is output during the period T of the first and one channel clocks of each frame (FIG. 3C).

The synchronization pattern prediction circuit 19 is constituted by a ring counter that counts the channel clock CK on the basis of the synchronization pattern detection pulse SY, and the signal level during the period T of the first and one channel clocks of each frame. This rising frame pulse FP is output (FIG. 3C). As a result, the sync pattern prediction circuit 19 predicts each frame sync and outputs the frame pulse FP even when the sync pattern detection circuit 18 cannot accurately detect the frame sync due to a defect or the like.

The disc identification code generation circuit 20 is constituted by the sub code detection circuit 20A and the read only memory (ROM) 20B. Here, the sub code detection circuit 20A decodes the binarized signal BD to reproduce the sub code information included in the binarized signal BD. The disc identification code generation circuit 20 selectively outputs time information of minutes AMIN and ASEC from time information by minutes, seconds, and frames included in this subcode information.

Here, the time information of minutes AMIN and seconds ASEC is sub code information determined in the standard of the compact disc 1, and indicates the position of data on the compact disc 1. That is, the time information of minutes AMIN represents data recorded on the compact disc 1 in units of minutes, and can take a value from 0 to 74, for example. In addition, the time information of seconds (ASEC) defines the position of the minute unit determined in minutes (AMIN), and also specifies in detail in seconds, and takes a value from 0 to 59.

The read-only memory device 20B retains the disk identification code ED and outputs data held by addressing the time information of the minutes and seconds of the output from the sub-code detection circuit 20A as the address. . Here, the disc identification code (ED) is composed of ID information that is set as unique to each disc, information according to the manufacturing plant, the date of manufacture, information to control copying / imposability, and the like, and a synchronization signal indicating the start of the disc identification code, Error correction codes and the like. The read-only memory device 20B holds the disk identification code ED by bit data, and has a one-bit disk identification code ED for an address of 1 based on time information of minutes AMIN and seconds ASEC. ) As a result, the read-only storage device 2OB outputs a disc identification code ED of 1 bit per second.

The modulation circuit 21 raises the control signal MX of the APC circuit 14 at a predetermined timing in accordance with the disc identification code ED, thereby raising the light amount of the laser beam instantaneously and thereby compact disc 1 Change the reflectance locally.

That is, as shown in FIG. 4, in the modulation circuit 21, the M series generating circuit 23 is composed of a plurality of cascaded flip-flops and an exclusive OR circuit, and time information of seconds (ASEC). After the initial values are set to the plurality of flip-flops at the timing corresponding to the change of, the set contents are sequentially transferred in synchronization with the frame pulse FP, and the logic is returned between the predetermined flip-flop stages. Generate random data (MS) of the M series in which 1) and logic (0) are equally probability. As a result, the M sequence signal MS becomes a sequence of pseudorandom numbers repeating the same pattern at a period corresponding to one bit of the disc identification code ED.

The exclusive OR circuit 24 receives the M series signal MS and the disk identification code ED and outputs this exclusive OR signal. That is, the exclusive OR circuit 24 outputs the exclusive OR signal by the logic level of the M series signal MS when the disc identification code ED is logic (0). In the case of the logic (1), an exclusive OR signal generated by inverting the logic level of the M series signal MS is output. As a result, the exclusive OR circuit 24 modulates the disk identification code ED by the M series random number.

The flip-flops 22A to 22P are cascade-connected so that the frame pulse FP is input to the flip-flop 22A at the first stage. These flip-flops 22A to 22P transmit this frame pulse FP in synchronization with the sequential channel clock CK.

The OR circuit 25 receives an output from the fifth stage flip-flop 22E and the sixteenth stage flip-flop 22P among these flip-flops 22A to 22P, and outputs their logic sum signals. do. As a result, when the frame sync starts and the period for 5 cycles of the channel clock CK has elapsed, the signal level rises by one channel clock cycle T, and the frame sync starts and the channel clock ( When the period of 16 cycles of CK) has elapsed, the pulse signal WP which raises a signal level by one channel clock period T is output. By doing so, the period in which the signal level of the pulse signal WP rises is one channel clock period T at each center between the pit of the period 11T forming the sync pattern and the land of the period 11T, respectively. It corresponds to a position separated by a sufficient distance at both edges of the pit and the land.

The AND circuit 26 outputs the exclusive OR signal output from the exclusive OR circuit 24 and the logical signal with the pulse signal WP as the light amount control signal MX of the APC circuit 14 (Fig. 3 (D)).

The APC circuit 14 (FIG. 1) changes the light amount of the laser beam from the light amount at the time of reproduction to the light amount at the time of recording in accordance with this light amount control signal MX. Here, the light amount at the time of recording is the light amount sufficient to change the reflectance of the reflective recording surface of the compact disc 1.

The system control circuit 28 is constituted by a computer that controls the operation of the entirety of the completion device 10, and searches for the optical pickup 13 based on the sub code detected by the sub code detection circuit 20A. The disc identification code ED is recorded in the predetermined area of (1).

As a result, the completion device 10 uses the laser beam according to the disc identification code ED modulated by the random number data MS at the pit center of the period 11T and the land center of the period 11T for forming the sync pattern. The amount of light is raised and the disc identification code ED is additionally recorded ((E-1) and (E-2) in Fig. 3). Therefore, in the compact disc 1, when the disc identification code ED is not additionally recorded, the reproduction signal RF is obtained by the signal waveform saturated almost uniformly in these pits and lands (Fig. 3). (F-1), in the case where the disc identification code ED is additionally recorded, the reproduction signal RF is obtained by locally varying the signal level in accordance with the characteristics of the reflective recording surface 3 near the center of the pit and land. ) Is obtained ((F-2) in FIG. 3). The compact disc 1 reproduces the disc identification code ED on the basis of the change in the signal level of the reproduction signal RF.

5 is a block diagram showing a compact disc player for playing the compact disc 1. In this compact disc player 30, the spindle motor 32 rotates the compact disc 1 under the condition of a constant linear speed under the control of the servo circuit 33. As shown in FIG.

The optical pickup 34 irradiates the compact disc 1 with a laser beam and receives the returned light, and outputs a reproduction signal RF whose signal level changes in accordance with the amount of the returned light. Here, the reproduction signal RF changes in signal level corresponding to the pit recorded on the compact disc 1. In this case, in the compact disc 1, the reflectance is formed locally by the recording of the disc identification code ED, so that the signal level of the reproduction signal RF is determined by the reflectance of the disc identification code ED. It changes according to the change. However, the reflectance changes locally by a predetermined distance from the pit and land edges of the period 11T so that the signal level of the reproduction signal RF is 2 in these pit and land. The timing across the reference level for tooth identification is maintained at the same timing as if the reflectivity had not changed at all.

As a result, the binarization circuit 35 binarizes the reproduction signal RF by a predetermined reference level, and generates the binarization signal BD. By doing in this way, since the change of the local reflectance in the compact disc 1 is made in the center of the pit and land of the period 11T, this change of the local reflectance is not detected by the binarized signal BD. .

The PLL circuit 36 operates on the basis of the binarized signal BD to reproduce the channel clock CCK of the reproduction signal RF.

The EFM demodulation circuit 37 sequentially reproduces the reproduction data corresponding to the EFM modulated signal S2 by sequentially latching the binarized signal BD based on the channel clock CCK. The EFM demodulation circuit 37 also EFM demodulates this reproduction data, and then deinterleaves the 8-foot unit signal generated by separating the demodulation data into 8-bit units based on the frame sync, and then corrects the error correction code (ECC). Output to the circuit 38.

The ECC circuit 38 performs error correction processing on the output data according to the error correction code added to the output data of the EFM demodulation circuit 37, thereby reproducing and outputting the audio data D1.

The digital / analog conversion circuit (D / A) 39 digitally / analog converts the audio data D1 output from the ECC circuit 38 to output an audio signal S4 made of an analog signal. At this time, the digital-to-analog conversion circuit 39 stops the output of the audio signal S4 when it is determined that the compact disc 1 is caused by illegal copying under the control of the system control circuit 40.

The system control circuit 40 is constituted by a computer that controls the operation of the compact disc player 30. The system control circuit 40 controls the entire operation so as to access a predetermined area of the compact disc 1 in advance, and the compact disc 1 in accordance with the disc identification code ED output from the disc identification code reproducing circuit 41. Is judged to be due to an illegal copy, and if it is determined to be due to an illegal copy, the output of the audio signal S4 from the digital / analog conversion circuit 39 is stopped and controlled.

The disc identification code reproducing circuit 41 decodes the disc identification code ED from the reproduction signal RF and outputs it.

6 is a block diagram showing the disc identification code reproducing circuit 41 in detail. In this disc identification code reproducing circuit 41, the sync pattern detecting circuit 43 sequentially latches the binary signal BD on the basis of the channel clock CCK and determines the successive logic level to detect the sync pattern. do. The sync pattern detection circuit 43 also outputs a frame pulse FP in which the signal level rises during the period T of the one-channel clock at which each frame starts based on the detected sync pattern.

The M series generating circuit 45 initializes the address at a predetermined timing under the control of the system control circuit 40, and then sequentially advances the address by the frame pulse FP to access the built-in read-only memory device. Thereby, M series random number data MZ corresponding to M series random number data MS generated by the completion device 10 is generated.

The analog / digital conversion circuit (A / D) 47 performs an analog / digital conversion process on the reproduction signal RF based on the channel clock CCK, and outputs an 8-bit digital reproduction signal. The polarity inversion circuit (-1) 48 inverts the polarity of this digital reproduction signal and outputs it.

The selector 49 selects the digital reproduction signal and the polarity inversion circuit 48 directly input from the analog / digital conversion circuit 47 according to the logic level of the M series random number data MZ output from the M series generation circuit 45. Selectively outputs a digital reproduction signal formed by reversing the input polarity. That is, the selector 49 selects and outputs a digital reproduction signal that is directly input when the M series random number data MZ is logic 1, and on the contrary, when the M series random number data is logic 0, Select the polarity-inverted digital playback signal. As a result, the selector 49 reproduces the logical level of the disc identification code ED modulated by the M series random number data MS by multi-value data, and outputs the reproduction data RX by the multi-value data. .

Like the modulation circuit 21 in the completion device 10, the pit center detection circuit 50 is composed of 16 stages of flip-flops cascaded and an OR circuit that receives a predetermined output of these flip-flops. The pit center detection circuit 50 sequentially transmits the frame pulses FP by these flip-flops so that the signal level is increased by one channel clock period T at the pit center of the period 11T and the land center of the period 11T. The rising center detection signal CT is output.

The sub code detection circuit 51 monitors the binarized signal BD based on the channel clock CCK, and decodes the sub code information from the binarized signal BD. The sub code detection circuit 51 also monitors time information in the decoded sub code information, and outputs a one second detection pulse SECP in which the signal level rises every time the time information changes by one second.

The adder 52 is a 16-bit digital adder, which adds and reproduces the reproduction data RX and the output data AX of the accumulator (ACU) 53. The accumulator 53 is composed of a 16-bit memory holding the output data of the adder 52, and forms a cumulative adder together with the adder 52 by returning the retained data to the adder 52. In other words, the accumulator 53 clears the contents held by the one-second detection pulse SECP, and then records the output data of the adder 52 at the timing of the center detection signal CT. As a result, the adder 52 accumulates the logical values of the reproduction data RX reproduced by the selector 49 every second of time information based on the sub code information (between 7350 frames), and outputs the accumulated value AX.

The binarization circuit 54 binarizes and outputs the output data AX of the accumulator 53 by a predetermined reference value at a timing at which the one-second detection pulse SECP rises. As a result, the reproduction data RX of the disc identification code ED reproduced by the selector 49 is converted into a binary disc identification code ED.

The ECC circuit 55 performs error correction processing on the disc identification code ED by the error correction code added to the disc identification code ED and outputs it.

(1-2) Operation of the First Embodiment

In the above structure, in the manufacturing process of the compact disc 1 which concerns on this embodiment, a mother disk is created by a normal mastering apparatus, and the disk board | substrate 2 is created by the stamper created from this mother disk. In addition, the reflective recording surface 3 and the protective film 4 are formed in this disk substrate 2, and the compact disc 1 is created (FIG. 2). As a result, the compact disc 1 repeats the pits and lands of the integral length corresponding to the predetermined basic period T, and records digital audio signals and the like.

At this time, the compact disc 1 is applied to the reflective recording surface 3 with the same film structure as the information recording surface of the CD-R. As a result, when the laser beam L is irradiated for a predetermined light amount or more, the compact disc 1 is located at this laser beam irradiation position. The reflectance of the reflective recording surface 3 is reversibly changed, and the sub data can be additionally recorded in addition to the main data recorded by the repetition of pits and lands.

In the compact disc 1 thus produced, a predetermined region is reproduced by the control of the system control circuit 28 in the completion device 10 (FIG. 1), and the digital audio signal recorded by repetition of pits and lands. The disc identification code (ED) is recorded in this predetermined area so as to have no effect on reproduction.

That is, in the completion apparatus 10, the reproduction signal RF obtained by the optical pickup 13 is converted into the binarization signal BD by the binarization circuit 16, and the synchronous pattern detection circuit 18 The sync pattern is detected in this binarized signal. Thereby, the start timing of these pit and land is detected regarding the pit and land of the longest period 11T among the pit and land formed in the compact disc 1. As shown in FIG.

In the subsequent synchronous pattern prediction circuit 19, a frame pulse FP in which the signal level rises at the start timing of the sync pattern is generated, whereby the binarized signal BD is not reproduced correctly due to a defect or the like. Even with the correct timing, the start timing is detected for the pits and lands of the period 11T.

In the modulation circuit 21 (FIG. 4), the frame pulses FP are sequentially transmitted in the flip-flops 22A to 22P, so that the outputs of the flip-flops of the fifth and sixteenth stages are the arc circuits 25. Is synthesized so that one channel clock period T of the central portion of the pit and one channel clock period T of the central portion of the land are detected for the pits and lands of these periods 11T.

In conjunction with these, the sub code is reproduced in the sub code detection circuit 20A (Fig. 1), and information specifying the reproduction position is detected from the sub code by minutes (AMIN) and seconds (ASEC). From the read-only memory device 20B, a disc identification code ED is output in correspondence with the information specifying these reproduction positions. At this time, the read-only storage device 20B holds the disk identification code ED by the bit information, and outputs the disk identification code ED accessed and held by the information of minutes AMIN and seconds ASEC. The disk identification code (ED) is output at a very low bit rate of 1 bit per second.

In addition, in the M series generating circuit 23, M series random number data MS in which logic 1 and logic 0 are generated with equal probability in synchronization with the frame pulse FP is generated, and an exclusive OR circuit ( 24), the disk identification code ED is modulated by this M series random number data MS. In the AND circuit 26, the output of this exclusive OR circuit 24 is gated by the output of the OR circuit 25, thereby modulating the disk identification code ED modulated by the M series random number data MS. ), A control signal MX is generated in which the signal level rises at each central portion of the pit and land of the period 11T.

In the compact disc 1, the light amount of the laser beam is increased by this control signal MX, and the reflectance of the reflective recording surface 3 is locally changed. As a result, the compact disc 1 is applied to each central portion of the pit and land of the period 11T. Marks are locally formed to form a disc identification code (ED).

These marks are formed in the center portion of the pits and lands of the period 11T, so that in the reproduction signals varying with the pits and lands, the signal levels corresponding to the respective edges of these pits and lands are different from those in which the marks are formed. The same signal level is maintained when no mark is formed. As a result, the disc identification code ED made of the sub data is recorded without any influence on the reproduction of the main data by the pit and the land.

That is, if NA of the optical system for reproducing data by this type of pit array is set to NA and the wavelength of the laser beam is λ, the light spot of diameter D1 represented by the following equation is displayed on the information recording surface of the compact disc 1; Is formed. In addition, diameter D1 is half value width in a light spot here.

[Equation 1]

As a result, when the mark is formed at a distance D from the front and rear edges, the mark and the edge are not scanned simultaneously in the light spot. On the other hand, the positional information of the edge is a timing at which the average level of the reproduction signal RF is set to a threshold value, so that the signal level of the reproduction signal RF crosses this threshold value, and the timing of the center of the optical spot is the edge. Corresponds to the crossing timing. In this timing, when the light beams do not irradiate the mark at the same time, the timing across this threshold value remains the same as when no mark is formed.

As a result, when the diameter D1 of Equation 1 is 1/2, and the mark is formed at a distance D1 at a distance D1 from the front and rear edges, the mark is formed by the pit and the land. The disc identification code ED made of the sub data can be reproduced without any influence on the reproduction of the main data.

[Formula 2]

Here, the general numerical aperture NA in the compact disc player is 0.45 and the wavelength lambda is 0.78 [μm]. When Equation 2 is solved, D = 1.06 [μm]. The compact disc 1 rotates at a linear speed of 1.2 [m / sec], and since the frequency of the channel clock CK is 4.3218 [MHz], the mark is separated by a distance corresponding to a four-channel clock period at the edge. If formed, the mark is created apart from the edge by the distance D1 according to the expression (2).

That is, when marks are formed by a distance corresponding to the period of about 4T or more from the edges of the pits and lands, the edge information of the pits and lands detected by the change in the amount of light of the returned light and the information by the marks are separated. Can play. As a result, the disc identification code ED made of the sub data is recorded without any influence on the reproduction of the main data by the pit and the land.

Further, at this time, the disc identification code ED is modulated by M series random number data MS in which logic 1 and logic 0 are equally probable, thereby changing the reproduction signal RF due to the change in reflectance. Is observed like noise mixed in the reproduction signal RF, whereby it may be difficult to observe and find the disc identification code ED. In addition, copying of the disk identification code ED may be difficult.

In addition to this, by allocating one bit of the disc identification code (ED) in one second period, i.e., distributing and recording all of the one bit into 7350 (7350 = 75 x 98) CD frames, the reproduction signal is reproduced by noise or the like. The disc identification code ED can be reliably reproduced even if is changed.

Further, the compact disc 1 in which the disc identification code ED is recorded in this manner is copied with respect to the digital audio signal D1 by the pit string by the conventional illegal copying technique, but the disc identification code ED ) Becomes difficult to copy.

That is, when making an illegal copy similarly to this compact disc 1, it is necessary to record the disc identification code ED by the same mark, and the digital audio signal D1 is previously recorded by the pit string. In addition, it is necessary to prepare a disk-type recording medium having a reflective recording surface. Moreover, it is also necessary to prepare the apparatus by the same structure as this completion apparatus 10. FIG. As a result, the disc identification code ED can be recorded with difficulty in copying.

That is, in the compact disc 1 thus produced (FIG. 5), the compact disc player 30 detects a reproduction signal RF whose signal level changes in accordance with the light amount of the returned light obtained by irradiating a laser beam. The signal level of the reproduction signal RF changes depending on the pit and the land and the reflectance of the compact disc 1, and the reproduction signal RF is binarized by the binarization circuit 35. Subsequently, the binarized signal BD is binarized and identified by the EFM demodulation circuit 37, and then EFM demodulated and deinterleaved to perform error correction processing by the ECC circuit 38, whereby the digital audio signal D1 is obtained. Is played.

At this time, in the compact disc 1, the mark formed by the locally changing reflectance corresponds to the period 4T at the pits and lands of the period 11T and at the edges (both of the front edge and the rear edge). By being formed in the center of the pit and land spaced more than a distance, the change of the signal level in the vicinity of each edge by forming this mark is prevented, and by this the compact disc which recorded the disc identification code ED (1) Can be accurately reproduced by a normal compact disc player.

In the reproduction of the digital audio signal D1 performed in this manner, the compact disc 1 has a predetermined area accessed beforehand, and the disc identification code ED is reproduced in this area. If the reproduction cannot be performed correctly, the digital / analog conversion processing by the digital / analog conversion circuit 39 is stopped and controlled as illegal copying.

That is, in the reproduction of the disc identification code ED (Fig. 6), the frame sync is detected by the sync pattern detecting circuit 43 in the compact disc 1, and the M series is generated based on the detection of the frame sync. In the circuit 45, M series random number data MZ corresponding to M series random number data MS at the time of recording is generated.

Also, the reproduction signal RF is converted into a digital reproduction signal by the analog / digital conversion circuit 47, and the digital reproduction signal or polarity is inverted by the selector 49 on the basis of the M series random number data MZ. The selected digital reproduction signal is selected to reproduce the reproduction data RX formed by expressing the logic level of the disc identification code ED by multi-value data.

In the compact disc 1, this reproduction data RX is accumulated by the accumulator 53 and the adder 52 in units of one second, thereby improving the SN ratio. The cumulative result is binarized by the binarization circuit 54 to decode the disk identification code ED, and is then subjected to error correction processing by the ECC circuit 55 and output to the system control circuit 40.

(1-3) Effects of the First Embodiment

According to the above structure, the pit and land of the sync pattern which consist of period 11T were detected, the mark was formed in the center of these pit and land which separated 4 cycles or more from the edge, and the disc identification code was recorded, and the edge was recorded. An optical pickup that locally changes the reflective films of the pit and the land at a timing that does not affect the positional information of the digital signal and reproduces the digital audio signal D1 without affecting the reproduction of the digital audio signal D1 by the pit rows. The disc identification code can be recorded so that it can be reproduced by an illegal copy and that copying is difficult by illegal copying.

In addition, the disc identification codes can be simply recorded using this regularity by recording disc identification codes with marks for the pit and land of the sync pattern regularly recorded.

In this case, by allocating and recording one bit of the disk identification code in the pit and land of the sync pattern allocated for about one second, the disk identification code can be reliably reproduced by avoiding the influence of noise and the like.

In addition, by modulating and recording the disk identification code by the M series random number data, the disk identification code can be recorded with noise and difficulty in identification, and the disk identification code can be found and difficult to interpret. In addition, the disk identification code can be reproduced by effectively avoiding the influence of noise during reproduction.

In addition, by forming the mark with a length corresponding to the basic period T, the disk identification code can be recorded in the same way as noise and difficulty in identification, and the disc identification code can be found and difficult to interpret.

Further, in the compact disc player, the signal level of the reproduction signal RF is detected to decode the disc identification code, and the signal level is accumulated to eliminate the influence of noise mixed in the disc identification code, thereby making it difficult to record noise and difficulty. The disc identification code ED can be reliably reproduced.

In the selector 49, the digital reproduction signal is selectively processed by the M series random number data MZ to reproduce the disc identification code, whereby the disc identification code recorded with difficulty in finding and analyzing can be reliably reproduced.

(2) Second Embodiment

7 is a block diagram showing a completion device according to a second embodiment of the present invention. The completion device 60 detects a pit of period 9T or more and records the disk identification code ED in these pit. In addition, in the structure shown in this FIG. 7, the structure similar to the completion apparatus 10 of FIG. 1 is attached | subjected with the code | symbol, and the overlapping description is abbreviate | omitted.

That is, in this completion device 60, the system control circuit 61 is constituted by a computer that controls the operation of the entirety of the completion device 60, and the light is based on the sub code detected by the reproduction signal RF. The operation of the pickup 13 is controlled, whereby the area set in the recording area of the disc identification code ED is traced by the optical pickup 13 two times in sequence.

At this time, the system control circuit 61 keeps the trace signal T1 in the logic 0 in the first trace, whereas the second control which continuously scans the point scanned by the first trace. In tracing, the trace signal T1 is changed to logic 1. In this case, the first trace is for detecting a pit more than the period 9T, and the second trace is for additionally recording the disc identification code at the pit more than the period 9T from the detection result.

The 9T abnormal pattern detection circuit 62 detects a pit more than the period 9T by detecting the pulse width of the channel clock 9T or more in the first trace.

That is, as shown in Fig. 8, the 9T or more pattern detection circuit 62 has 13 stages of flip-flops 64A to 64M that are cascade-connected, and the binarized signal BD at the first stage of these flip-flops 64A to 64M. Enter). These flip-flops 64A to 64M transfer sequential input data in synchronization with the channel clock CK.

The AND circuits 65A to 65C input the outputs of these flip-flops 64A to 64M, respectively, to output logical signals. At this time, the AND circuit 65A inverts the logic level with respect to the output output from the flip-flops 64A, 64B, 64L, and 64M of the first stage, the second stage, the twelfth stage, and the last stage, thereby inputting the logic. When the output of "O011111111100" is obtained, that is, when the logic level corresponding to the pit shape of the length 9T is continuous, the logic level of the logical signal is raised.

Subsequently, the AND circuit 65B inverts the logic level with respect to the output from the flip-flops 64A, 64L, and 64M of the first stage, the twelfth stage, and the last stage, thereby outputting the logic " 0011111111110 " If obtained, i.e., if the logic level corresponding to the pit shape of length 100T is continuous, the logic level of the logical signal is raised.

The AND circuit 65C inverts the logic level with respect to the outputs output from the flip-flops 64A and 64M at the first and last stages, whereby the output of logic "0111111111110" is obtained, that is, the length 11T. If the logic level corresponding to the pit shape is continuous, the logic level of the logical signal is raised.

The OR circuit 66 calculates a logical sum of the output signals outputted from the AND circuits 65A to 65C, so that when a pit of any one of the periods 9T, 10T, and 11T is detected, the logical sum signal becomes logical " 1 ". Outputs (MD). The flip-flop 67 samples the logical sum signal MD at the channel clock CK to form a waveform to remove the influence of glitch noise and output the detection pulse NP.

The pattern prediction circuit 63 of 9T or more changes the operation according to the logic level of the trace signal T1 output from the system control circuit 61, so that the positional information is obtained with respect to the pit of period 9T or more in the first trace. In the second trace, the timing signal EP for recording the disc identification code is output in accordance with the recorded positional information.

That is, as shown in Fig. 9, in the 9T or more pattern prediction circuit 63, the sub code detection circuit 69 is written as a sub code by processing the binarized signal BD on the basis of the channel clock CK. The positional information (frame AFRAME, second (ASEC), minute (AMIN)) of the compact disc 1 is reproduced. In this case, the frame AFRAME is positional information divided into 75 equal parts for one second. Further, the sub code detection circuit 69 decodes the SO flag (composed of a sub-coding sync pattern) included in the sub code and outputs it as a sub code flag (SOFLAG) representing one frame of the sub code.

The sync pattern detection circuit 70 detects a sync frame by monitoring a continuous logic level of the binarized signal BD based on the channel clock CK, and the sync frame detection signal whose signal level rises at the start timing of each frame. Outputs (SY).

 The sync pattern prediction circuit 71 is constituted by a ring counter that counts a channel clock based on the sync frame detection signal SY, whereby a sync frame is not detected by the sync pattern detection circuit 70 due to a defect or the like. Even in this case, the frame pulse FP without defect is sent out using the sync frame periodicity.

The counter 72 is constituted by a ring counter that counts up the channel clock CK based on the frame pulse FP, whereby a count value composed of position information such as dividing the inside of one EFM frame by 588 ( EFMC). The counter 72 counts up the frame pulse FP on the basis of the sub code flag SOFLAG, thereby creating a count value CDC composed of position information for dividing 1 CD frame by 98. FIG.

In this way, when outputting the count values EFMC and CDC, the counter 72 raises the frame pulse FP when the trace signal Tl is logic 0 (that is, the first trace). When the trace signal T1 is the logic 1 for counting up the continuous channel clock CK such that the count value EFMC becomes the value 0 at the timing to be set (that is, the second trace) ), The continuous channel clock CK is counted up so that the count value EFMC becomes the value 7 at the timing when the frame pulse FP rises.

Here, the seven periods of the channel clock CK corresponding to this value 7 output the timing signal EP by the count value EFMC to the laser beam irradiation position specified by the count value EFMC. It corresponds to the delay time until the light amount of a laser beam rises. As a result, in the second trace, the counter 72 counts up the channel clock CK such that the delay time minute and the count value EFMC advance.

The memory 74 is composed of position information (frames AFRAME, seconds (ASEC), minutes (AMIN)) by the sub code detection circuit 69, and count values (EFMC, CDC) formed by the position information by the counter 72. Is composed of a memory for recording the detection pulse NP with the address as an address, and the operation is changed in accordance with the trace signal T1. That is, when the trace signal T1 is logic 0 (that is, the first trace), the memory 74 is outputted from the pattern detection circuit 62 with 9T or more as its address information. Record the detection pulse NP. On the other hand, when the trace signal T1 is the logic 1 (that is, the second trace), the memory 74 stores the contents held with these position information as addresses as the timing signal EP. Output

The modulation circuit 75 is configured similarly to the modulation circuit 21 described above with respect to FIG. That is, the modulation circuit 75 cascades a predetermined number of flip-flops and sequentially transmits the frame pulse FP in the channel clock period by the flip-flops. In addition, the modulation circuit 75 receives an output at a predetermined number of stages of these flip-flops, whereby the period T of the one-channel clock is passed when the period 4T or more passes from the start edge of the pit for a period 9T or more. Generates a timing signal at which the logic level rises by.

In addition, the modulation circuit 75 generates M series random number data based on the timing signal EP, and modulates the disk identification code ED by the random number data. Further, the modulation result is gated by the timing signal generated by the flip-flop and output as the control signal MX.

As a result, the completion device 60 is configured to record the disc identification code with respect to the pit of the period 9T or more that satisfies the condition described for the expression (2).

That is, in the pit of period 9T or more, even if the reflectance is changed by the period 1T apart from the start edge by the period 4T, the reflectance can be changed without affecting the positional information of the front and rear edges. Moreover, in the pit of this period 9T or more, the frequency | count of occurrence is high compared with the pit and land of the period 11T. As a result, one bit of the disc identification code can be recorded in many pit, and the reliability of the disc identification code can be improved by that much.

By doing so, in the case of reproducing the compact disc according to the present embodiment, the pits of 9T or more are detected by the pattern detection circuit having the same configuration as the 9T or more pattern detection circuit 62 applied to the completion device 60. In this regard, the signal level of the reproduction signal RF is detected to reproduce the disc identification code.

According to the configuration of the second embodiment, even if a pit longer than or equal to 9T is detected and the reflectance of the information recording surface is locally changed at a timing separated by a predetermined distance from the edge of the pit, the disc identification code is recorded. The same effect as in the embodiment can be obtained. In addition, the disc identification code can be recorded using the pit which is generated more frequently than in the first embodiment, so that the disc identification code can be reliably recorded, and the time allocated to one bit of the disc identification code as necessary. Can be shortened to improve the recording density of the disc identification code.

(3) Third embodiment

Fig. 10 is a block diagram showing the completion device of the compact disc 1 according to the third embodiment. In the completion device 80, a pit detection process of a period 9T or more and an additional recording process of a disc identification code are executed simultaneously and in parallel. In addition, in the structure shown in this FIG. 10, the structure similar to the completion device 60 mentioned above regarding FIG. 7 is shown with the code | symbol, and the overlapping description is abbreviate | omitted.

That is, in this embodiment, the completion device 80 is a recording optical pickup for delaying scanning by a predetermined time the scanning trajectory scanned by the preceding reading optical pickup 83A and the preceding reading optical pickup 83A. 83B).

As a result, the completion device 80 processes the reproduction signal RF obtained by the preceding optical pickup 83A, detects the pit more than the period 9T, and further writes the recording optical pickup (following the detection result). 83B), the disc identification code ED is recorded.

That is, the completion device 80 inputs the detection result NP of the pattern detection circuit 62 of 9T or more to the FIF0 memory 84, and supplies it to the modulation circuit 75 with a predetermined time delay to advance optical pickup ( The delay time until the recording optical pickup 83B scans the scan trajectory scanned by 83A) is compensated for.

The system control circuit 82 is constituted by a computer that controls the operation of the completion device 80, and searches the optical pickups 83A and 83B to the recording position of the disc identification code.

According to the configuration shown in Fig. 10, the time required for the processing can be shortened in addition to the same effect as in the second embodiment by simultaneously executing the pit detection processing of the period 9T or more and the additional recording processing of the disc identification code in parallel. .

(4) another embodiment

In the above embodiment, the case where the CD-ROM film structure is applied to the reflective recording surface has been described. However, the present invention is not limited to this, and the film structure of the phase change type optical disk can also be applied. In addition, since the change of reflectance is very good at least, it is also possible to use reflecting films, such as a normal aluminum alloy.

Further, in the first embodiment, when the reflectance of the information recording surface is locally changed by 5 or more periods at the edge of the pit, in the second and third embodiments, the period is 4T or more at the edge of the pit. Although the case where the reflectance of the information recording surface is locally changed is described above, the present invention is not limited to this. The effect can be obtained.

In addition, by reducing the amount of change in the reflectance, it is also possible to record information using all pits and spaces regardless of the pit size.

In other words, when the reflectance of the information recording surface of the edge portion of the pit is slightly changed, jitter is generated in the reproduction signal. In an actual compact disc player, however, even if some jitter occurs in the reproduction signal from the pit, the data in the pit rows can be reproduced without any problem at all. Therefore, when such deterioration of the jitter can be tolerated, it is also possible to record the disc identification code by changing the reflectivity of all the pit or space by a small amount (about 2%) regardless of the pit size or the length of the space.

In relation to this jitter, in the EFM system used for modulating a compact disc, for example, the minimum inversion interval is a three-channel clock. This minimum inversion interval is defined as the distance that the occurrence of jitter by the change is almost negligible even if a change in the pit such as a reflectance change occurs at a point separated by this minimum inversion interval from the edge of the pit. As a result, when the disc identification code ED is additionally recorded at a position apart from the edge of the pit by a minimum reversal interval, the deterioration of jitter caused by the disc identification code ED can be kept at a sufficiently small value, thereby ensuring the data of the pit row. Can play. Therefore, for example, in the case of a compact disc, the disc identification code can be recorded by changing the reflectance locally by a distance corresponding to the three-channel clock at the edge of the pit.

In the case where the disc identification code is recorded at a distance corresponding to the three-channel clock from the edge of the pit in this manner, the disc identification code can be recorded in the pit and land of the period 7T or more.

Incidentally, in the above second and third embodiments, the case where the disc identification code is recorded in the pit more than the period 9T has been described. However, the present invention is not limited to this, so that the disc is recorded in the pit and land more than the period 9T. can do.

Further, in the second and third embodiments, the case where the disc identification code is recorded at intervals of the pit start side by a period 4T in the pit more than the period 9T is described. The recording can be performed in the center of each pit of the period 9T or more without limitation.

It is also possible to record the disc identification code by using the land portion rather than the pit. In general, since the land portion has a higher reflectance than the pit portion, recording and reproduction may be easy as a result by recording on the land portion.

In the first embodiment, the disc identification code is recorded in the predictable sync frame portion. However, the present invention is not limited thereto, and the present invention can be applied to any signal if it is possible to predict the appearing signal in advance. There is a number. For example, when all or part of the signals recorded on the compact disc type are known, it is possible to predict the disc type pit array. Even in this case, the disk identification code ED can be additionally recorded by applying the present method to anticipate a place sufficiently far from the edge portion of the pit to instantly increase the laser output at the expected place.

Incidentally, in the above embodiment, a case is described in which the reflectance of the information recording surface is locally changed by only one channel clock period with a pit of a predetermined length or more. However, the present invention is not limited to this, and the yaw is provided at the front edge and the rear edge. If the reflectance is partially changed by a predetermined distance, the disc identification code can be recorded without damaging the edge information. For example, for the pits and lands of the period 9T, the reflectance is changed by the center period 3T. You can.

Incidentally, in the above embodiment, a case has been described in which the disc identification code is recorded. However, the present invention is not limited to this, but the digital audio signal encrypted by the pit is recorded, and key information necessary for releasing this encryption is recorded. For example, various types of data necessary for canceling encryption can be recorded, such as selecting key information or recording data for decryption.

Incidentally, in the above embodiment, the case where the disc identification code is recorded in the compact disc completion apparatus is described. However, the present invention is not limited to this, and is applied to the compact disc player to reproduce data by, for example, pit rows. The number of times and the number of copies can be recorded.

Incidentally, in the above embodiment, a case has been described in which the cumulative value by the accumulator is reproduced by binary to reproduce the sub data string formed by the disc identification code. Can be played.

In the above embodiment, the digital audio signal is recorded by EFM modulation. However, the present invention is not limited to this, but is applied to various modulations such as 1-7 modulation, 8-16 and 2-7 modulation. Widely applicable to

In the above embodiment, the case where the desired data is recorded by the pit has been described. However, the present invention is not limited to this, but can be widely applied to the case where the desired data is recorded by the mark and space.

In the above embodiment, although the audio signal is recorded by applying the present invention to a compact disc and its peripheral device, the present invention is not limited to this, but various optical discs such as a video desk and its peripheral device are described. Widely applicable to

As described above, according to the present invention, by changing the reflectance of the recorded reflective film of the pit, it is possible to reproduce the main data string by the optical pickup which reproduces the main data string without any influence on the reproduction of the main data string. By illegal copying, the sub data string can be recorded with difficulty in copying.

Claims (44)

An optical pickup for irradiating a light beam to a disc-shaped recording medium in which the pits and lands or marks and spaces according to the length of the main data string are repeated on the information recording surface, and the main data string is recorded in advance; Locally the said pit and / or land or the mark and / or space of a predetermined length or more are spaced apart by a predetermined distance from an edge of the pit or mark recorded on the information recording surface based on a sub data string. And recording means for changing the reflectance of the information recording surface and for additionally recording the sub data string on the disc-shaped recording medium. The method of claim 1, And one bit of the sub data string is repeatedly recorded in a plurality of the pits and / or lands or the marks and / or spaces. The method of claim 1, Optical disc recording, characterized in that the sub data string is recorded on the disc-shaped recording medium by locally changing the reflectance of the information recording surface according to the data string obtained by modulating the sub data string by M series random numbers. Device. The method of claim 1, The predetermined distance is the following formula:

Wherein the NA is a numerical aperture of the optical system for reproducing the main data sequence, and? Is a wavelength D of the optical beam applied to the optical system. The method of claim 1, And the predetermined distance is the shortest length of the pits and lands or the marks and spaces formed in the disc-shaped recording medium. The method of claim 1, And the sub data string comprises an identification data string for identifying the disc-shaped recording medium. The method of claim 1, The main data string is composed of an encrypted data string, And the sub data string comprises a data string necessary for decryption of the main data string. The method of claim 1, And the sub data string comprises reproducing count data of the main data string. The method of claim 1, And the sub data string comprises copy number data of the main data string. The method of claim 1, Detection means for detecting pits and / or lands or marks and / or spaces of the predetermined length or more based on the returned light obtained by irradiating a light beam, and outputting a detection result; Storage means for temporarily holding the detection result; Control means for scanning the light beam into bits and / or lands, marks and / or spaces corresponding to the detection result held in the storage means; And an amount of light switching means for temporarily raising the light amount of the light beam and locally changing the reflectance of the information recording surface based on the detection result held in the storage means and the sub data string. Disc burner. The method of claim 1, A first optical system for irradiating the disc-shaped recording medium with a first light beam to receive return light and output a light reception result; Detection means for detecting bits and / or lands or marks and / or spaces of the predetermined length or more based on the light reception result, and outputting a detection result; The second optical beam is irradiated onto the disc-shaped recording medium following the first optical beam by the first optical system, and based on the detection result and the sub data string, the light amount of the second optical beam is temporarily And a second optical system which raises and locally changes the reflectance of the information recording surface. Pits and lands or marks and spaces according to the length of the main data string are repeated on the information recording surface to irradiate light beams onto the disc-shaped recording medium on which the caution data is recorded in advance, Locally the said pit and / or land or the mark and / or space of a predetermined length or more are spaced apart by a predetermined distance from an edge of the pit or mark recorded on the information recording surface based on a sub data string. An optical disk recording method, characterized in that the sub data string is additionally recorded on the disc-shaped recording medium by changing the reflectance of the information recording surface. The method of claim 12, 1 bit of the sub data string is repeatedly recorded in a plurality of the pits and / or lands or the marks and / or spaces. The method of claim 12, Optical disc recording, characterized in that the sub data string is recorded on the disc-shaped recording medium by locally changing the reflectance of the information recording surface according to the data string obtained by modulating the sub data string by M series random numbers. Way. The method of claim 12, The predetermined distance is the following formula:

Wherein NA is a numerical aperture of the optical system for reproducing the main data string, and λ is a wavelength of the light beam applied to the optical system. The method of claim 12, And the predetermined distance is the shortest length of the pits and lands or the marks and spaces formed on the disc-shaped recording medium. The method of claim 12, And the sub data string comprises an identification data string for identifying the disc-shaped recording medium. The method of claim 12, The main data string is composed of an encrypted data string, And the sub data string comprises a data string necessary for decrypting the main data string. The method of claim 12, And the sub data string comprises reproducing count data of the main data string. The method of claim 12, And the sub data string comprises copy number data of the main data string. The method of claim 12, Based on the returned light obtained by irradiating the light beam, the pits and / or lands or marks and / or spaces of the predetermined length or more are detected, Predict the timing at which the light beam scans the bits and / or lands, marks, and / or spaces above the predetermined length from the detection result; And the reflectance of the information recording surface is locally changed by temporarily raising the light amount of the light beam based on the prediction result and the sub data string. The method of claim 12, Based on the returned light obtained by irradiating the light beam, the pits and / or lands or marks and / or spaces of the predetermined length or more are detected to temporarily hold the detection results, Scanning the same location again, based on the temporarily held detection result and the sub data string, temporarily increases the light amount of the light beam, and locally changes the reflectance of the information recording surface. Way. The method of claim 12, Irradiating a set of light beams to the disc-shaped recording medium, and temporarily increasing the amount of light of the following light beams based on the result of reproduction by the preceding light beams, thereby locally changing the reflectance of the information recording surface. An optical disc recording method. Pits and lands or marks and spaces based on the length of the main data string are repeated in advance on the information recording surface, and the main data string is recorded. With respect to the pit and / or land or the mark and / or space of a predetermined length or more, at a portion spaced from the edge of the pit or mark by a predetermined distance, a portion formed by locally changing the reflectance of the information recording surface is formed. An optical disc, characterized in that an additional data string is additionally recorded. The method of claim 24, 1 bit of the sub data string is repeatedly recorded in a plurality of the pits and / or lands or the marks and / or spaces. The method of claim 24, And the sub data stream is modulated by an M series random number and recorded. The method of claim 24, The predetermined distance is the following formula:

Wherein NA is a numerical aperture of the optical system for reproducing the main data string, and λ is a wavelength of the light beam applied to the optical system. The method of claim 24, And the predetermined distance is the shortest length of the pits and lands or the marks and spaces. The method of claim 24, And the sub data string comprises an identification data string identifying an optical disk. The method of claim 24, The main data string is composed of an encrypted data string, And the sub data string comprises a data string necessary for decrypting the main data string. The method of claim 24, And the sub data string comprises reproducing count data of the main data string. The method of claim 24, And the sub data string comprises copy number data of the main data string. An optical disc reproducing apparatus which irradiates a laser beam to an optical disc and reproduces data recorded on the optical disc by the return light of the optical disc. In the optical disc, pits and lands or marks and spaces of lengths corresponding to the main data string are repeated on the information recording surface, and the main data string is recorded in advance. In a part spaced apart from the edge of the pit or mark by a predetermined distance with respect to the pit and / or land or the mark and / or space of a predetermined length or more, a portion formed by locally changing the reflectance of the information recording surface is formed. Additional data strings are recorded, The optical disk reproducing apparatus, Light receiving means for receiving the returned light and outputting a light receiving result; Binarization means for binarizing the light receiving result; Main decoding means for processing the output signal of said binarization means to reproduce said main data string; Sub-decoding means for reproducing the sub data string based on the signal level of the light reception result; And control means for controlling the output of said main data string by said main decoding means in accordance with said sub data string reproduced by said sub decoding means. The method of claim 33, wherein The encoding and decoding means, M series generating means for generating a predetermined M series, Calculating means for calculating the light reception result and the M series; Integrating means for integrating the calculation result of the computing means during a predetermined integration period; And identification means for identifying an integration result of the integration means and outputting the sub data string. The method of claim 34, wherein And the sub-decoding means outputs the sub data string outputted from the identification means by error correction processing. delete delete delete delete delete delete delete delete delete

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