JP2010218665A - Optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform destruction of data with reliability and stability by making effictive use of an unrecorded area of a write-once optical disk and detecting radiation power necessary and optimam for the destruction of data of the write-once optical disk. <P>SOLUTION: An optical disk device 100 has: a pickup 154; a condition setting record section 212 which irradiates a groove of the unrecorded area of an optical disk 130 with a laser beam, to record a mark, and then carries out overwrite recording by changing radiation power of the laser beam stepwisely; a reproduced signal detection section 156 which reproduces the overwritten data, to obtain a reproduced signal; and a overwrite recording section 214 which calculates laser beam radiation power the asymmetry rate of which is a predetermined value or higher, from the laser beam radiation power changed stepwisely on the basis of the reproduced signal, and carries out the overwrite recording on the mark of a part in the data area of the optical disk and a recorded area of the data area by using the calculated laser beam radiation power. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus for overwriting data on a write-once optical disc.

  An optical disc such as a CD (Compact Disc), a DVD (Digital Versatile Disk), or a BD (Blu-ray Disc) has a small occupying volume and is inexpensive, has a large recording capacity, and can accommodate a large amount of data in a compact manner. On the other hand, even if a part of the data recorded on the optical disc becomes unnecessary, it is not possible to simply discard the optical disc on which a large amount of data is recorded from the viewpoint of preventing information leakage. In particular, write-once optical discs such as CD-R and DVD-R are not easy to update or erase data, and once written data is maintained effectively unless special data destruction processing is performed.

  In order to solve this problem, it is possible to write an optical disc that can destroy existing data by further overwriting (superimposing) the data on a data recording area of a write-once optical disc in which recorded data is no longer needed. A read-in device is known (for example, Patent Document 1). Also disclosed is a technique in which data modulated by a run length constraint modulation method that is the same as the run length constraint of the data modulation method already recorded on a write-once optical disc is used for overwriting (for example, Patent Document 2). ).

Japanese Patent Laid-Open No. 9-097432 JP 2006-048763 A

  However, in the prior art documents as described above, there is little description of the irradiation power of the specific laser beam when data is overwritten on the data recorded on the write-once optical disc, and the irradiation power necessary for data destruction is specified. I couldn't. In Patent Document 2, there is a description that, when data is overwritten, irradiation is performed at the same level as the irradiation intensity of the laser beam at the time of reproduction, but there is no way of grasping whether the data has been securely overwritten by the irradiation intensity. Therefore, trials with an appropriately set irradiation power had to be repeated.

  In this way, when data is overwritten on a write-once optical disc in a situation where the appropriate laser beam irradiation power cannot be grasped, if the laser beam irradiation power required for the overwrite is too small, the data destruction is insufficient. There is a risk of information leakage. On the other hand, if the irradiation power is too large, the servo gain increases as the tracking error signal rises, and the tracking control becomes unstable, which hinders normal data overwriting.

  In addition, when data on the write once optical disk is continuously overwritten, the irradiation power fluctuates due to changes over time such as the laser diode of the pickup for recording data and the ambient temperature, and the destruction of the data is still insufficient. Or the servo system became unstable.

  In view of such problems, the present invention detects the optimum laser beam irradiation power necessary and necessary for data destruction of a write-once optical disk by effectively using an unrecorded area of the write-once optical disk, and ensures reliable and stable data destruction. An object of the present invention is to provide an optical disc apparatus capable of performing the above.

  In order to solve the above problems, an optical disc apparatus according to the present invention is a write-once type in which lands and grooves are alternately formed along a radial direction, and a plurality of zones are formed along the circumferential direction in the groove. Data is recorded by irradiating a laser beam on the groove of the optical disc to form a mark, or by irradiating a laser beam on the groove in which the data of the write-once optical disc is recorded, and detecting the reflected return light. And a condition setting recording unit for overwriting by changing the irradiation power of the laser beam stepwise after irradiating the laser beam to the groove in the unrecorded area of the write-once optical disc and recording the mark. A reproduction signal detector that reproduces the overwritten data to obtain a reproduction signal, a mark formed on the groove, and a space other than the mark formed When the ratio of the reproduction signal obtained from each of the mark and the space obtained at a ratio of 50% is used as a reference, the ratio of the reproduction signal deviating from the reference is referred to as an asymmetry ratio. Based on the obtained reproduction signal, the laser beam irradiation power whose asymmetry ratio is equal to or greater than a predetermined value is calculated from the laser beam irradiation power changed stepwise, and the calculated laser beam irradiation power is calculated. And an overwrite recording unit that overwrites and records on a mark of a recorded part of the data area in the data area of the write-once optical disc. Here, the predetermined value may be 23% or more.

  In the present invention, the unrecorded area (first area) of the write-once optical disc is effectively used, and the irradiation power of the laser beam at which the asymmetry ratio of the reproduction signal becomes a predetermined value or more, that is, necessary for data destruction of the write-once optical disc. Optimal laser light irradiation power is detected. With this configuration, it is possible to perform stable data destruction while maintaining tracking control effectively. In addition, by using the first area where the data to be destroyed is not recorded as the area for detecting the irradiation power of the laser beam, a portion where the data destruction is insufficient is generated in the first area. However, actual damage does not occur, and the data in the second area, which is the recorded part of the data area as the destruction target, can be reliably destroyed.

  The optical disk apparatus, when overwriting onto a mark in the data area of a write-once optical disk and already recorded in the data area, immediately after moving to the next zone, obtains the asymmetry ratio and groove obtained in advance. An irradiation power correction unit that corrects the overwrite laser irradiation power of the immediately preceding zone using the relationship with the overwrite laser irradiation power of the previous zone and continues the overwrite recording to the next zone may be further provided.

  In a write-once optical disc, data is generally recorded in units of zones or sound tracks. Therefore, due to the difference in recording timing, changes with time such as the laser diode of the pickup and the ambient temperature are likely to occur between zones or between sound tracks. In the present invention, the irradiation power of the laser beam can be corrected based on the asymmetry ratio of the reproduction signal of the new zone or sound track at the boundary of the zone or sound track where the switching timing can be grasped. Stable data destruction is possible regardless of changes over time such as diodes and ambient temperature.

  The optical disc apparatus stores completion information having a result of completing overwriting on a mark in the data area of the write-once optical disc and already recorded in the data area, and identification information associated with the result. You may further provide the completion information production | generation part to produce | generate.

  Content data (digital content data) that can be recorded on a write-once optical disc is protected by copyright, and the number of dubbing operations may be limited. At this time, if the content data of the write-once optical disc that has been dubbed is inadvertently destroyed, the limited number of dubbing operations is substantially reduced. In the present invention, the management information for managing the number of times of dubbing is linked with the completion information for proving destruction of the write-once optical disc, and the limit on the number of times of dubbing is returned by one according to the destruction of the content data, thereby unintentionally reducing the number of times of dubbing Can be avoided.

  The optical disk apparatus further includes an error correction unit that performs error correction on the data of the overwritten portion by changing the irradiation power of the laser beam in a stepped manner, and the overwriting recording unit cannot perform error correction. The recording power may be overwritten on the groove in the data area of the write-once optical disc and the already recorded portion of the data area with the irradiation power of the laser beam.

  With this configuration, it is possible to detect the optimum laser beam irradiation power necessary and necessary for data destruction of a write-once optical disc based on whether or not error correction can be performed in addition to or independently of the asymmetry ratio of the reproduction signal. Thus, reliable and stable data destruction can be performed.

  The optical disk apparatus according to the present invention performs reliable and stable data destruction by detecting an optimum irradiation power of laser light necessary for data destruction of the write-once optical disk by effectively using an unrecorded area of the write-once optical disk. Is possible.

1 is a functional block diagram showing an electrical configuration of an optical disc device according to an embodiment. It is explanatory drawing which showed the specific structure of the disk drive part concerning this embodiment. It is explanatory drawing which showed transition of the irradiation power of the laser beam in the overwrite of the data to the 1st area | region concerning this embodiment. It is an eye pattern for demonstrating the asymmetry ratio of the reproduction signal concerning this embodiment. It is explanatory drawing which showed transition of the asymmetry ratio of the reproduction signal of the 1st field concerning this embodiment. It is explanatory drawing for demonstrating the relationship information concerning this embodiment. It is explanatory drawing for demonstrating the predetermined timing which stops overwriting of the arbitrary data to the 2nd area | region concerning this embodiment. It is the flowchart which showed the specific process of the data recording method concerning this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(Optical disk device 100)
FIG. 1 is a functional block diagram showing an electrical configuration of the optical disc apparatus 100 according to the present embodiment. The optical disk device 100 includes a disk drive unit 110, a data buffer 112, an image signal output unit 114, an audio signal output unit 116, and a central control unit 118.

  The disc drive unit 110 reproduces content data recorded on the optical disc 130 such as a CD, DVD, or BD, transmits it to the data buffer 112, and holds it in the data buffer 112 in response to a user operation input to the optical disc device 100. The desired content data thus recorded is recorded on the optical disk 130. Hereinafter, when expressed simply as the optical disk 130, it includes at least a write-once optical disk such as a CD-R or DVD-R.

  On the optical disc 130, lands and grooves are alternately formed adjacent to each other in the radial direction. When the optical disk 130 is a write-once optical disk, data is obtained by recording a mark (dent) on the groove. A portion where no mark is recorded is a space.

  FIG. 2 is an explanatory diagram showing a specific configuration of the disk drive unit 110. The disk drive unit 110 includes a transport mechanism 150, a rotation mechanism 152, a pickup 154, a reproduction signal detection unit 156, and an error correction unit 158.

  The transport mechanism 150 includes a tray 170 and its drive unit (not shown), and transports the tray 170 loaded with the optical disk 130 forward and backward in the direction of the white arrow in accordance with a user operation input.

  The rotating mechanism 152 includes a clamper 174 provided with a magnetic body 172, a turntable 178 provided with a magnet 176 for attracting the magnetic body 172, and a spindle motor 180 connected to the turntable 178, and is conveyed. The optical disk 130 transported by the mechanism 150 is clamped by the clamper 174 and the turntable 178, and the spindle motor 180 rotates the optical disk 130 together with the clamper 174 and the turntable 178.

  The pickup 154 irradiates the groove of the optical disk 130 rotating according to the rotation mechanism 152 to form a mark to record data, or irradiates the groove on which the data of the optical disk 130 is recorded with laser light. Then, the reflected return light is detected to reproduce the data.

  At the time of data reproduction by the pickup 154, since the optical disk 130 is rotating, the position of the track on the recording surface with respect to the pickup 154 slightly varies in the radial direction and the perpendicular direction to the recording surface due to the eccentricity or inclination of the optical disk 130 or the spindle motor 180. To do. Therefore, the pickup 154 performs tracking control in the radial direction and focus control in the vertical direction of the recording surface by tracking servo and focusing servo in addition to the above-described rough movement in the radial direction, and follows the fluctuation of the track.

  For example, in tracking control, when the pickup 154 is deviated from the center of the track of the optical disk 130, the deviation amount is grasped through a tracking error signal, and the pickup 154 is moved in a direction to cancel the deviation amount. Thus, the relative position in the radial direction between the pickup 154 and the track is maintained within a predetermined error range.

  However, when recording the data through the pickup 154, if the irradiation power of the laser beam required for the recording is too small, the track cannot be correctly tracked (traced), and the servo may be lost. On the contrary, even if the irradiation power of the laser beam is too large, the amplitude (sensitivity) of the tracking error signal increases, and the servo deviation may occur as follows.

  Tracking control during recording is performed in a state where the laser beam irradiation power (write power) during mark recording and the laser beam irradiation power (read power) during playback to leave as a space are frequently switched. Of the average value servo system in which the average value of the return light reflected by the recording surface of the optical disk 130 and the return light of the reproduction laser light reflected by the recording surface of the optical disk 130 is calculated and servoed. In this case, as the write power increases, the return light also increases in proportion to it, and the amplitude (sensitivity) of the tracking control signal increases accordingly, and the servo loop gain increases. Conversely, if the write power becomes too low, the control becomes unstable and the servo is lost.

  As another servo method, there is also a method in which only the return light at the previous read power is sampled. In this case, even if the light power changes slightly, it will not be affected, but if the light power becomes too high and the return light exceeds the input level of the photodetector and it becomes in a state of clipping, the characteristics of the photodetector Even when switching from 1 to read power, the output level does not return to the normal value, and a high state is sampled, and the loop gain becomes high and the servo becomes unstable.

  As described above, when the loop gain continues to increase, tracking control becomes unstable, and finally, servo detachment may occur due to oscillation. In the present embodiment, reliable and stable data destruction is performed by controlling the irradiation power of the laser beam during recording to an appropriate value.

  The reproduction signal detector 156 detects a reproduction signal (RF (Radio Frequency) signal) at each recording position of the data on the optical disk 130 through the pickup 154. Further, the reproduction signal detection unit 156 includes a peak detection circuit 182 that detects a peak value of the reproduction signal, a bottom detection circuit 184 that detects a bottom value of the reproduction signal, and a low-pass filter circuit that derives an average value of the reproduction signal. 186.

  In the optical disk 130, data is recorded so as to indicate “1” when the mark and the space are switched, and “0” when the mark and the space are not switched, but the 8-bit original data is EFM so that the change points are not continuous. (Eight to Fourteen Modulation) is converted to 14 bits and recorded. According to such EFM, the mark and the space have a length of at least 3 bits, and the appearance rate of the mark and the space is 50% respectively. Therefore, the average value from the low-pass filter circuit 186 in one recording shows the center value of the peak value from the peak detection circuit 182 and the bottom value from the bottom detection circuit 184. The average value, peak value, and bottom value are used in the overwriting recording unit 214 described later.

  The error correction unit 158 performs error correction of data on the optical disc 130 through the pickup 154. Among the optical disks 130, for example, a DVD-R employs a parity system called a Reed-Solomon code as an error correction system, and several to several tens of each ECC (Error Correcting Code) block according to the number of bits of horizontal parity and vertical parity. Byte errors can be corrected. The error correction unit 158 corrects such an error, and when the error correction is normally completed, the error correction unit 158 transmits the number of error portions for which the error correction has been executed to the central control unit 118, and the error correction is not normally completed. In other words, if error correction does not function effectively, a message to that effect is sent to the overwriting recording unit 214. Further, according to the instruction from the overwriting recording unit 214, error correction is performed when the laser beam irradiation power is changed stepwise.

  The data buffer 112 is configured by an HDD or a VRAM, and holds content data of the optical disc 130 reproduced by the disc drive unit 110 and content data acquired through a communication network such as the Internet or broadcast.

  The image signal output unit 114 extracts the image data in the content data from the data buffer 112, converts it into a video signal, and outputs it to the monitor 132.

  The audio signal output unit 116 extracts the audio data in the content data from the data buffer 112, converts it into an audio signal, and outputs the audio signal to the speaker 134.

  The central control unit 118 is configured by a semiconductor integrated circuit including a central processing unit (CPU), and manages and controls the entire optical disc apparatus 100 in cooperation with the RAM and other components. In this embodiment, the central control unit 118 includes a recording area extraction unit 210, a condition setting recording unit 212, an overwriting recording unit 214, a relationship information generation unit 216, an irradiation power correction unit 218, a management information generation unit 220, and a completion. It functions as the information generator 222.

  The recording area extraction unit 210 extracts a first area that is an unrecorded area on the optical disc 130 through the pickup 154. Here, the first area refers to an area remaining without being recorded in the power calibration area or data area on the optical disc 130. The second area described later is an area where data is recorded in the data area on the optical disc 130 and is overwritten and destroyed.

  The condition setting recording unit 212 irradiates the groove of the first region with laser light and records a mark, and then changes the irradiation power of the laser light stepwise to record arbitrary data by overwriting. Here, random data is used as arbitrary data, and the laser beam irradiation power uses an average value or a previous value at the time of recording.

  FIG. 3 is an explanatory diagram showing the transition of the irradiation power of the laser light in overwriting data in the first area. The condition setting recording unit 212 changes the average irradiation power at the time of reproduction to the point a which is the boundary of the first region, and from the point a indicating the entire length of the first region from the point d slightly inside the point d. Record data at point c.

  Here, although the irradiation power is changed stepwise, the average value of the irradiation power at the time of recording is used as the center value in order to appropriately perform correction by the irradiation power correction unit 218 described later. Further, when data is being recorded, the condition setting recording unit 212 maintains a correspondence relationship so that the irradiation power of the laser beam when the recording is performed from the recording position can be specified later. In FIG. 3, the data is overwritten by the irradiation power of seven steps, but the number of steps is not limited to this, and it can be divided into smaller steps or can be changed linearly.

The overwrite recording unit 214 causes the reproduction signal detection unit 156 to detect the reproduction signal of the first region after the condition setting recording unit 212 overwrites the data in the first region, and the reproduction signal obtained by the reproduction signal detection unit 156 Based on the above, the laser beam irradiation power with which the asymmetry ratio is equal to or greater than a predetermined value is calculated from the laser beam irradiation power changed stepwise. Here, the reproduction signal asymmetry ratio [%] is based on the ratio of the reproduction signal obtained from each of the mark and the space when the mark and the space formed on the groove are present at a ratio of 50%. , The ratio of the reproduction signal deviates from the reference, and the values detected by the peak detection circuit 182, bottom detection circuit 184, and low-pass filter circuit 186 of the reproduction signal detection unit 156 are the average value Avg and the peak value, respectively. When Pek is the bottom value Btm, the deviation of the average value, which is the difference between the center value and the average value, is divided by the fluctuation range.
((Pek + Btm) / 2−Avg) / (Pek−Btm) × 100 (Equation 1)
Can be expressed as

  FIG. 4 is an eye pattern for explaining the asymmetry ratio of the reproduction signal. After recording the first data, the reproduction signal has a length of at least 3 bits and is formed corresponding to the uniformly appearing marks and spaces. Therefore, as described above, the average value Avg of the reproduction signal is located between the peak value Pek in the space and the bottom value Btm in the mark. When the average value Avg, the peak value Pek, and the bottom value Btm are applied to the equation 1, the asymmetry ratio is almost 0%.

  However, in the second data recording (overwriting), a mark (dent) is formed in the portion that was a space in the first time, but the portion that was a mark cannot be returned to the space. Is the logical sum of the mark at the first recording and the mark at the second recording, and the appearance frequency of the mark is higher than the space. Then, the average value Avg is displaced to be lower than the intermediate value between the peak value Pek in the space and the bottom value Btm in the mark, and the asymmetry ratio becomes a positive value.

  For example, when recording is performed with stepwise irradiation power as shown in FIG. 3, the asymmetry ratio of the reproduction signal in the first region increases stepwise as shown in FIG. Referring to FIG. 5, the asymmetry rate is stable at 0% up to the point b where no overwriting is performed and the region from the point c, but the asymmetry rate is maintained from the point b where the overwriting is performed to the point c. Becomes a positive value and the absolute value of the asymmetry ratio increases as the irradiation power of the laser beam increases.

  Subsequently, the overwrite recording unit 214 sets the irradiation power corresponding to the recording position where the asymmetry ratio of the reproduction signal is a predetermined value, which is 23% or more in the present embodiment, as the optimum irradiation power for overwriting. Here, the predetermined value is set to 23% if the asymmetry ratio is 1.5 times or more of the upper limit of −5 to 15%, which is a standard value of a reproduction signal that can correctly restore data. This is because it can be considered that the data has been destroyed. Further, the overwrite recording unit 214 sets the irradiation power corresponding to the recording position at which the error correction by the error correction unit 158 becomes impossible in addition to or independently of the asymmetry ratio of the reproduction signal. It can also be set as the irradiation power.

  Then, the overwriting recording unit 214 irradiates the pickup 154 with the optimum laser beam for overwriting set on the marks in at least the second area where data is recorded, other than the first area of the optical disk 130. Use power to overwrite any data.

  In the present embodiment, as described above, the unrecorded first area of the optical disk 130 is effectively used as a trial area for deriving the optimum irradiation power of laser light for overwriting. Accordingly, even if the optical disk 130 is in a different recording state, or even when the disk drive unit 110 has changed over time, the irradiation power at which the asymmetry ratio of the reproduction signal is a predetermined value or more, that is, It is possible to detect the optimum irradiation power necessary and necessary for data destruction of the optical disk 130.

  With such a configuration, it is possible to absorb the variation of the optical disk 130 and the disk drive unit 110 and perform stable data destruction while keeping tracking control effective.

  In addition, by using the first area where the data to be destroyed is not recorded as the area for detecting the irradiation power of the laser beam, a portion where the data destruction is insufficient is generated in the first area. However, actual damage does not occur, and it is possible to reliably destroy the data in the second area to be destroyed.

  The relation information generation unit 216 causes the reproduction signal detection unit 156 to detect the reproduction signal of the first region, and the asymmetry ratio of the reproduction signal of the first region detected by the reproduction signal detection unit 156 and the laser beam required for the overwriting thereof. The relation information showing the relation with the irradiation power of is generated.

  FIG. 6 is an explanatory diagram for explaining the relationship information. By associating the irradiation power of the laser light in the first region shown in FIG. 3 with the asymmetry ratio of the reproduction signal in the first region shown in FIG. 5, reproduction with respect to the irradiation power of the laser light as shown in FIG. The transition of the signal asymmetry ratio (related information) is derived and used for the irradiation power correction unit 218 described later.

  When the irradiation power correction unit 218 performs overwriting recording on the mark in the second area, the relationship between the asymmetry ratio obtained in advance by the reproduction signal detection unit 156 at a predetermined timing and the overwrite laser irradiation power to the groove Is used to correct the immediately preceding overwrite laser irradiation power, and the overwriting recording is continued with the corrected laser irradiation power. Specifically, the reproduction signal detector 156 feeds back the asymmetry ratio of the reproduced signal, and performs a closed-loop control in which a difference from the target asymmetry ratio is applied as the irradiation power of the laser beam, thereby reproducing the asymmetry of the reproduction signal. When the sex ratio falls below the target value (23%), the laser beam irradiation power is increased to reliably destroy the data. When the sex ratio exceeds the target value (23%), the laser beam irradiation is performed to maintain tracking control. Reduce power.

  With this configuration, it is possible to grasp fluctuations in the asymmetry ratio of the reproduction signal at every predetermined timing, and perform uniform data destruction regardless of changes over time such as the laser diode of the pickup that records data and the ambient temperature. It becomes possible.

  Further, the irradiation power correction unit 218 corrects the irradiation power of the laser light based on the relationship information generated by the relationship information generation unit 216. By using the relationship information indicating the relationship between the asymmetry ratio of the reproduction signal and the irradiation power of the laser light for correcting the irradiation power, the target value of the asymmetry ratio of the reproduction signal and the current value of the asymmetry ratio of the reproduction signal are obtained. From this difference, the irradiation power to be increased or decreased can be accurately derived, stable data destruction can be achieved by optimal closed-loop control, and tracking error signals are sampled when data is overwritten (sampling position, etc.) Can also be predetermined.

  The predetermined timing for stopping overwriting of arbitrary data in the second area by the overwrite recording unit 214 may be a timing at which the zone on the DVD or the sound track on the CD is switched. Here, the zone and the sound track indicate a data recording unit and are represented by a capacity that is an integral multiple of the ECC block.

  FIG. 7 is an explanatory diagram for explaining a predetermined timing for stopping overwriting of arbitrary data in the second area.

  In the optical disc 130, data is generally recorded in units of zones or sound tracks as shown in FIG. Therefore, due to the difference in recording timing, changes with time such as laser diode and ambient temperature are likely to occur between zones or between sound tracks. Here, the irradiation power of the laser beam can be corrected based on the asymmetry ratio of the playback signal of the new zone or sound track at the boundary of the zone or sound track where the switching timing can be grasped. Therefore, stable data destruction is possible by absorbing the difference in the recording state.

  However, if the irradiation power correction unit 218 detects the reproduction signal of the data in the second area overwritten immediately before the boundary of the zone or sound track is strictly exceeded, the new zone or sound track that is originally required is detected. The playback signal cannot be detected. Therefore, it is desirable that the irradiation power correction unit 218 detects the reproduction signal when it slightly exceeds the zone or sound track boundary, for example, after 2 to 3 seconds.

  Further, as shown in FIG. 7B, the predetermined timing may be set every predetermined capacity, for example, every 500 Mbytes from the innermost circumference when the optical disk 130 is a DVD-R. With such a configuration, it is possible to review the irradiation power of laser light for each predetermined capacity, and stable data destruction is possible.

  Furthermore, as the predetermined timing, as shown in FIG. 7C, the logical sum of the above-described zone or sound track boundary and the boundary for each predetermined capacity can be taken. However, since the boundary of the zone or sound track and the boundary of each predetermined area are poorly related, an area with a small recording capacity of, for example, 100 Mbytes or less may occur due to the logical sum of the two. In this case, unnecessary subdivision of the area can be avoided by arbitrarily integrating with the front and back areas.

  The management information generation unit 220 generates management information for managing the number of times of dubbing when the content data is protected by copyright and the number of times of dubbing is limited to, for example, 1, 3, and 10. The management information is associated with the identifier of the content data and the remaining number of times that dubbing is possible, and the management information generation unit 220 decrements the remaining number of times of management information every time content data is dubbed. Further, when the content data transferred (checked out) to the external device is returned to the optical disc apparatus 100 (check-in), the management information generating unit 220 increments and returns the remaining number of decrements.

  When the overwriting recording unit 214 completes overwriting of arbitrary data in the second area, the completion information generating unit 222 displays the result of completing the overwriting recording on the mark and the identification information associated with the result. Completion information is generated.

  As described above, content data that can be recorded on the optical disc 130, particularly digital content data, is protected by copyright, and the number of dubbing operations is limited. At this time, if the content data of the optical disk 130 dubbed with care is inadvertently destroyed, the number of times of dubbing that is limited is substantially reduced. Here, the management information managed by the management information generation unit 220 and the completion information that proves the destruction of the optical disk 130 are linked, and the limit of the number of times of dubbing is returned by one according to the destruction of the content data. Reduction can be avoided.

  As described above, the above-described optical disc apparatus 100 detects the laser beam irradiation power necessary and optimum for data destruction of the optical disc 130 by effectively using an unrecorded area of the optical disc 130, and performs reliable and stable data destruction. Is possible.

(Data recording method)
Next, a data recording method using the above-described optical disc apparatus 100 will be described. FIG. 8 is a flowchart showing specific processing of the data recording method according to the present embodiment.

  If there is a destructive input of the optical disk 130 by the user (YES in S300), the recording area extraction unit 210 of the optical disk apparatus 100 extracts the first unrecorded area on the optical disk 130 through the pickup 154 (S302). The unit 212 causes the pickup 154 to record arbitrary data in the first area (S304), and further overwrite arbitrary data in the first area while gradually increasing the irradiation power of the laser light (S306).

  Then, the reproduction signal detection unit 156 detects the reproduction signal at each recording position in the first area where the data is overwritten, through the pickup 154 (S308).

  Subsequently, the overwrite recording unit 214 derives the irradiation power of the laser beam corresponding to the recording position where the asymmetry ratio of the reproduction signal detected by the reproduction signal detection unit 156 is equal to or greater than a predetermined value (S310), and the pickup 154 Then, arbitrary data is overwritten on the mark in the second region by using the derived irradiation power of the laser beam (S312).

  Even with such a data recording method, it is possible to perform the reliable and stable data destruction by detecting the optimum irradiation power of the laser light necessary and necessary for the data destruction of the optical disk 130 by effectively using the unrecorded area of the optical disk 130. It becomes.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  Note that each step in the data recording method of the present specification does not necessarily have to be processed in time series in the order described in the flowchart, and may include processing in parallel or by a subroutine.

  The present invention can be used in an optical disc apparatus that overwrites data on a write-once optical disc.

DESCRIPTION OF SYMBOLS 100 ... Optical disk apparatus 130 ... Optical disk (write-once type optical disk)
152... Rotation mechanism 154... Pickup 156... Reproduction signal detection unit 158... Error correction unit 210... Recording area extraction unit 212 ... Condition setting recording unit 214 ... Overwrite recording unit 216. ... Management information generator 222 ... Completion information generator

Claims (5)

Lands and grooves are formed alternately along the radial direction, and a plurality of zones are formed along the circumferential direction of the groove. Or a pickup for reproducing the data by irradiating the groove on which the data of the write-once optical disc is recorded with a laser beam and detecting the reflected return light;
A condition setting recording unit for overwriting recording by irradiating the groove in the unrecorded area of the write-once optical disc with the laser beam and recording the mark, and then changing the irradiation power of the laser beam in a stepped manner,
A reproduction signal detector that reproduces the overwritten data to obtain a reproduction signal;
When the ratio of the reproduction signal obtained from each of the mark and the space when the mark formed on the groove and the space other than the mark is present at a ratio of 50% is used as a reference When the ratio of the reproduction signal deviates from the reference is called asymmetry ratio,
Based on the reproduction signal obtained by the reproduction signal detection unit, the irradiation power of the laser beam at which the asymmetry ratio is equal to or greater than a predetermined value is calculated from the irradiation power of the laser beam changed in a stepped manner. Using the calculated laser beam irradiation power, an overwrite recording unit for overwriting on the mark in the data area of the write-once optical disc and the already recorded portion of the data area; ,
An optical disc apparatus comprising:   When overwriting on the mark that is in the data area of the write-once optical disc and is already recorded in the data area, immediately after moving to the next zone, the asymmetry ratio obtained in advance and the Using a relationship with the overwrite laser irradiation power to the groove, further comprising an irradiation power correction unit for correcting the overwrite laser irradiation power of the immediately preceding zone and continuing the overwrite recording to the next zone. 2. The optical disk apparatus according to claim 1, wherein   Completion information having a result of completion of overwrite recording on the mark that is in the data area of the write-once optical disc and already recorded in the data area, and identification information associated with the result is generated The optical disc apparatus according to claim 2, further comprising a completion information generation unit that performs the operation.   4. The optical disc apparatus according to claim 1, wherein the predetermined value is 23% or more. The laser beam irradiation power is changed stepwise, and further comprises an error correction unit that performs error correction of the overwritten recorded data,
The overwrite recording unit has an irradiation power of the laser beam that has made the error correction impossible, is in the data area of the write-once optical disc, and is on the groove of the recorded part of the data area. 5. The optical disc apparatus according to claim 1, wherein overwriting is recorded on the optical disc apparatus.

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