JP2011118961A - Method, device, and program for evaluating data recording, and optical information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for evaluating data recording which quickly derives an evaluation index value that contributes to comprehensive evaluation and correction of recording conditions. <P>SOLUTION: The method comprises the steps of: detecting a reproduction signal, detecting reproduction data from the reproduction signal by a PRML signal process; calculating, with respect to predetermined data patterns included in the reproduction data, a first evaluation index value for each data pattern on the basis of a reproduction signal after a PR process corresponding to the data pattern and an ideal signal of the reproduction signal after the PR process corresponding to the data pattern; and setting again the data patterns subjected to calculation in the evaluation index value calculation step, on the basis of the first evaluation index value for each calculated data pattern. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for evaluating data recording on an optical disc.

  A method of evaluating the recording state by irradiating a laser beam onto the information recorded area of the optical disk and obtaining the recording state of the recorded area using the return light, and the recording power and recording using the evaluation result Conventional methods for setting the pulse include a method that evaluates the reproduced signal alone such as jitter, β, and asymmetry, and a method that evaluates the deviation from the ideal by comparing it with the ideal signal that should be detected. Is generally known.

  The former evaluation / setting method is often used in recording power adjustment called OPC (Optical Power Calibration) performed in a test area prior to recording of recording information. As the latter evaluation / setting method, for example, those described in Patent Documents 1 to 5, and those called SbER and PRSNR are known. These are effective techniques for evaluating / setting data recorded with high density as in the Blu-ray standard.

  However, the latter method is effective for comprehensive evaluation of the recording state, but it is a total evaluation, and if one parameter condition is optimized, the other parameter condition that was previously adjusted deviates from the optimal state. Therefore, it is not a sufficient technique when optimizing some or each of a plurality of parameters of recording power and recording pulse conditions.

  On the other hand, various methods have been proposed to solve such a problem (see, for example, Patent Documents 6 and 7). However, these methods have a problem that a comprehensive evaluation of the recording state cannot be performed.

  In view of the above circumstances, the applicant proposes a recording state evaluation method that is capable of comprehensive evaluation of the recording state and that is suitable for optimizing some or each of a plurality of parameters of the recording pulse waveform condition. (See Patent Document 8). This evaluation method is based on the premise that reproduction data is detected by PRML processing (Partial Response Maximum Likelihood) signal processing, and a reproduction signal after PR processing corresponding to the data pattern and a predetermined data pattern included in the reproduction data The difference between the reproduction signal after PR processing corresponding to the data pattern and the ideal signal is used as the evaluation index value. Specifically, a first evaluation index value for each data pattern, a first evaluation index value for each data pattern, and a second evaluation index value calculated from the appearance probability of the data pattern are calculated. Since the first evaluation index value is obtained for each data pattern, it is suitable for correcting the recording conditions for each data pattern. On the other hand, the second evaluation index value is suitable as a comprehensive index value for correcting recording conditions.

JP 2003-151219 A JP 2002-197660 A JP 2003-303417 A JP 2003-141823 A JP 2004-335079 A JP 2007-323781 A JP 2006-344382 A JP 2008-165863 A

  Incidentally, the evaluation index value described in Patent Document 8 not only serves as an evaluation index value in development / design of an optical disc drive or the like, but also contributes to correction of recording conditions by performing an evaluation process in the optical disc drive. For this reason, a mode in which the calculation processing of the evaluation index value is performed in the optical disk drive is preferable, and it is required to be able to calculate as fast as possible with high load.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a data recording evaluation method capable of deriving evaluation index values that contribute to comprehensive evaluation and correction of recording conditions at a low load and at high speed. There is to do.

  In order to achieve the above object, the present invention provides an optical information recording / reproducing system for recording / reproducing information by irradiating an optical information recording medium with laser light, and reproducing information from the reflected light of the laser light irradiated on the optical information recording medium. A reproduction signal detection step for detecting a signal, a PRML processing step for detecting reproduction data from the reproduction signal by PRML (Partial Response Maximum Likelihood) signal processing, and a predetermined data pattern included in the reproduction data corresponding to the data pattern A first evaluation index value calculating step for calculating a first evaluation index value for each data pattern based on a reproduction signal after PR processing and an ideal signal of the reproduction signal after PR processing corresponding to the data pattern; A second evaluation index for calculating a second evaluation index value based on the first evaluation index value of the data pattern and the appearance probability of the data pattern A value calculation step, a determination step for determining whether the recording state is good or not based on one or both of the first evaluation index value and the second evaluation index value, and the determination step determines that the recording state is not good. A data pattern selection step for selecting a data pattern to be calculated in the evaluation index value calculation step based on the calculated first evaluation index value for each data pattern, and the selected data pattern as the evaluation index And a resetting step for resetting as a calculation target in the value calculating step.

  According to the present invention, after calculating the first and second evaluation index values, a data pattern to be subjected to the calculation process is reset based on the first evaluation index value. In this resetting, the number of data patterns to be processed is reduced at least from the first time, so that it is possible to reduce the amount of calculation in the subsequent calculation processing of the first and second evaluation index values. As a result, the processing load can be reduced and the processing speed can be increased.

  Here, more specifically, the first evaluation index value is a statistically calculated value based on a value obtained by quantifying the distance between the reproduction signal after PR processing and the ideal signal, and is calculated for each data pattern. Is done. More specifically, the first evaluation index value is a value obtained by quantifying the distance between each reproduction signal after PR processing and the ideal signal when a plurality of reproduction signals are acquired for one data pattern. It is preferable to calculate the average value. The second evaluation index value is a statistically calculated value based on the first evaluation index value of each data pattern and the appearance probability of the data pattern, and more specifically, the first evaluation index value of each data pattern. This is the total sum of all data patterns obtained by multiplying the evaluation index value by the appearance probability of the data pattern.

  As an example of a preferable aspect of the present invention, in the determination step, it is determined that the recording state is not good when the second evaluation index value exceeds the first threshold value. In this case, in the data pattern selection step, it is preferable to select a data pattern in which the first evaluation index value exceeds the second threshold as a calculation target in the evaluation index value calculation step. Further, in the data pattern selection step, the top N (N is a natural number of 1 or more) data patterns having a low evaluation of the first evaluation index value may be selected as a calculation target. Here, the second threshold is preferably calculated by multiplying the first threshold by a predetermined constant (contribution).

  In the present invention, when it is determined in the determination step that the recording state is not good, the write strategy at the time of data recording is based on one or both of the first evaluation index value and the second evaluation index value. It is preferable that a correction step for correcting these parameters is included.

  As described above, according to the present invention, after calculating the first and second evaluation index values, the data pattern to be subjected to the calculation process is reset based on the first evaluation index value. In this resetting, the number of data patterns to be processed is reduced at least from the first time, so that it is possible to reduce the amount of calculation in the subsequent calculation processing of the first and second evaluation index values. As a result, the processing load can be reduced and the processing speed can be increased.

System configuration diagram of optical information recording / reproducing apparatus Diagram explaining the concept of PRerror The figure explaining the correlation between PRerror_ttl and SER Graph showing PRerror_ptn (p) for each data pattern Flowchart for explaining evaluation index value calculation and recording condition optimization processing

  A data record evaluation apparatus according to an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a data recording / evaluating apparatus is built in the optical information recording / reproducing apparatus. FIG. 1 is a system configuration diagram of an optical information recording / reproducing apparatus. In FIG. 1, only the configuration according to the present invention is shown, and other configurations are omitted. In this embodiment, the Blu-ray standard will be described as an example of an optical information recording / reproducing apparatus.

  As shown in FIG. 1, the optical information recording / reproducing apparatus 100 is an apparatus that records and reproduces data by irradiating an optical disc 10 with a laser beam 20. An optical information recording / reproducing apparatus 100 performs overall control of operations of an optical pickup 200 that emits and receives laser light 20, a recording system apparatus 300, a reproduction system apparatus 400, an evaluation apparatus 500, and each apparatus. It is roughly divided into a control unit that does not.

  The recording apparatus 300 includes an error correction encoding unit 310 that uses ECC encoding or the like for data (user data) to be recorded, and 1-7PP that performs 1-7PP modulation on the error correction encoded data. The modulation unit 320, the recording compensation processing unit 330 that performs various corrections on the modulated signal from the 1-7PP modulation unit 320 so as to optimize the recording state on the optical disc 10, and the recording compensation processing unit 330 And a laser driving unit 340 for driving the laser diode of the optical pickup 200 based on the signal.

  The reproduction system apparatus 400 includes a Pre-EQ 410 that performs waveform equalization processing on a reproduction signal from a light receiving element of the optical pickup 200, and an ADC (Analog Digital Converter) 420 that digitizes the analog reproduction signal that has been subjected to waveform equalization. A PRML processing unit 430 that performs PRML (Partial Response Maximum Likelihood) processing on the digitized playback signal, and 1-7PP demodulation processing on the playback signal derived by PRML processing before error correction. 1-7PP demodulator 440 for deriving a data string, and error correction decoder 450 that performs error correction on the output data of 1-7PP demodulator 440 and outputs reproduced data (user data). Here, the PRML processing unit 430 includes a PR equalizer 431 that performs PR equalization processing on a digitized reproduction signal, and a reproduction signal that has been PR equalized by a maximum likelihood signal (ML) technique. And a Viterbi decoder 432 for selecting and combining the most probable signal sequences. In the present embodiment, the PR equalizer 431 employs PR (1, 2, 2, 1) characteristics because it conforms to the Blu-ray standard.

  Since the configuration and operation of the optical pickup 200, the recording system device 300, the reproduction system device 400, and the control unit are the same as those of the conventional one, detailed description thereof is omitted. Next, the evaluation apparatus 500 will be described in detail.

  First, the evaluation index value derived in the present invention will be described. In the present invention, how much the signal after PR equalization (hereinafter referred to as PR equalization signal) by the PRML processing unit 430 deviates from the ideal signal of the PR equalization signal is calculated as an evaluation index value. Then, two values are calculated as the evaluation index values. The first evaluation index value is an evaluation index value for each data pattern. In the present application, it is expressed as PRerror_ptn (p) (p represents a data pattern). The second evaluation index value is an evaluation index value calculated from PRerror_ptn (p) for each data pattern. In this application, it is written as PRerror_ttl. Here, the data pattern means a combination of mark (pit) length and space (land) length.

  The former PRerror_ptn (p) will be described with reference to FIG. FIG. 2 shows an example of an amplitude level when a pattern in which a 3T-long space is adjacent to both sides of a 4T-long mark is read. In the figure, the vertical axis represents the amplitude level, and the horizontal axis represents the data sample number. When the PR (1, 2, 2, 1) used in the Blu-ray standard is used as the PR equalization ideal signal in such a data pattern, 1, 3, 5, 6, 5, 3, 1 On the other hand, as shown in FIG. 2, the actual detection signal deviates from the ideal state depending on hardware, media, and recording conditions. Therefore, in the present application, PRerror_ptn (p) is calculated by the following equation (1) in order to quantify the deviation amount (distance) between the ideal signal and the detection signal and evaluate the recording state.

  Here, D (x) is the value of the PR equalized signal, R (x) is the value of the ideal signal, x is the number of the sampled data, a is the calculation start data number, and n is the number of calculation data samples [pieces] , P represents the recording pattern type (number). For example, PRerror_ptn (p) is calculated using 7 points centered on the peak value when a = 1 and n = 7, but with 3 points centered on the peak value such as a = 3 and n = 3. PRerror_ptn (p) may be calculated. In addition, p is a number assigned to specify a recording pattern, and the number is the number of recording patterns necessary for evaluation, and varies depending on how many code sequences are defined as the unit configuration of the recording pattern. Come. In the example of FIG. 2, one recording pattern is configured by space_mark_space or mark_space_mark, but the pattern may be configured by a combination other than this.

  The expression (1) shows the calculation when the recording pattern p is detected once. However, in actuality, a plurality of values (cnt (p)) are considered in consideration of the influence of recording or detection variation. It is desirable to obtain an average value of. cnt (p) is the detection count number of the recording pattern p obtained in the sample data of a predetermined length, and in deriving the final value of PRerror_ptn (p), PRerror_ptn (p) calculated for each detection Is preferably recorded as PRerror_ptn (p, cnt (p)) in a memory (not shown) and averaged.

  The latter PRerror_ttl is calculated by the following equation (2).

  Here, the appearance frequency (p) is the appearance probability (or appearance frequency) of the recording pattern p in a predetermined data range.

  As a result of the experiment and research by the applicant, it has been found that the above PRerror_ttl is strongly related to the current evaluation indices DC jitter (DCJ) and symbol error rate (SER). It was also found that PRerror_ptn for each data pattern constituting PRerror_ttl is also strongly related to the recording state of the data pattern. Accordingly, in the present invention, the write compensation parameter in the recording compensation processing unit 330 is corrected using these evaluation index values. For the relationship between PRerror_ptn and PRerror_ttl and the current evaluation index value and write strategy, refer to Patent Document 9.

  Next, the evaluation apparatus 500 will be described in detail with reference to FIG. 1 again. As shown in FIG. 1, the evaluation apparatus 500 sequentially identifies a mark length and a space length from an output signal of the PRML processing unit 430 and outputs a mark length or space length data string, and a code identification unit A detection command unit 520 that detects the appearance of a predetermined data pattern from the data string identified in 510 and commands the calculation of PRerror, and an ideal signal by PR processing for the predetermined data pattern detected by the detection command unit 520 An ideal signal generation unit 530, a delay unit 540 for synchronizing the ideal signal generated by the ideal signal generation unit 530 and the PR equalization signal from the PR equalizer 431, a PR equalization signal, And an evaluation index value calculation unit 550 for calculating PRerror_ptn (p) and PRerror_ttl based on the ideal signal. Note that each unit of the evaluation apparatus 500 may be realized by a combination of a program for executing each function and a processor. At that time, the program may be stored in a memory in the processor.

  The detection command unit 520 varies the data pattern to be detected according to the number of evaluations in the optical disc 10, the form of evaluation processing, and the like. In the case of the first evaluation value calculation process in the optical disc 10, that is, when PRerror_ptn (p) and PRerror_ttl are calculated for the first time, all data patterns are detected. On the other hand, when the evaluation value calculation process is performed after the second time, that is, after calculating PRerror_ptn (p) and PRerror_ttl, data selected from all data patterns based on PRerror_ptn (p) and PRerror_ttl calculated for the first time The pattern is the detection target. Here, the first evaluation value calculation process is performed in a test recording performed prior to the main recording of user data. The second and subsequent evaluation value calculation processes are processes that are performed again after correcting the recording conditions as a result of evaluating the evaluation index value in the same test recording and determining that the recording state is not good. Alternatively, the second and subsequent evaluation value calculation processes are processes that are performed when the recording process is temporarily stopped when performing WOPC (Walking Optimum Power Control) in the main recording. The data pattern to be detected is set by the control unit.

  Here, the evaluation criteria of the recording state by the evaluation index value will be described. Whether or not the recording state is good is determined by whether or not PRerror_ttl exceeds the first threshold during the first evaluation process. In the second and subsequent evaluation processes, determination is made based on whether or not PRerror_ptn (p) of each data pattern to be calculated exceeds the second threshold value.

  As the first threshold value, it is preferable to use a value obtained from a correlation between an evaluation parameter used in compatibility verification with a recording medium and PRerror_ttl. Such an evaluation parameter may be a general evaluation index such as SER or DCJ, or may be a unique evaluation index used by a manufacturer during design and development. Then, the first threshold value may be calculated based on the spec value of the evaluation parameter and the correlation between the evaluation parameter. Here, the specification value of the evaluation parameter is a reference value for determining OK / NG in stably reproducing the data recorded on the medium, and the manufacturer side according to the design specifications and capabilities of the recording / reproducing machine. It may be set in. Further, the first threshold value may be recorded in a predetermined memory in advance, or the threshold value itself or data necessary for calculating the threshold value may be recorded in a predetermined area of the optical disc 10. May be read and used.

  FIG. 3 shows an example of the correlation between SER and PRerror_ttl as an example of the evaluation parameter. As shown in FIG. 3, it can be seen that SER and PRerror_ttl are correlated with each other by the function f. Thus, for example, when the SER spec value is 1.0E-03 or less, it is understood that PRerror_ttl is 0.176 or less, and therefore 0.176 may be adopted as the first threshold value.

  The second threshold value is preferably calculated based on the first threshold value. For example, a product of the first threshold value and a predetermined constant 1 / k (for example, 1/50) is preferable. This constant 1 / k is a contribution indicating the degree to which one data pattern contributes in PRerror_ttl. Note that k is an arbitrary value, and is appropriately selected and determined according to the design specifications and capabilities of the recording / reproducing device. Further, the second threshold value may be recorded in a predetermined memory in advance, or the threshold value or contribution (1 / k) itself or data necessary for calculating these values may be stored in a predetermined area of the optical disc 10. It may be recorded and used by reading it. FIG. 4 shows a graph for explaining the second threshold value. The graph of FIG. 4 is a plot of PRerror_ptn (p) for each data pattern when one mark and one space are combined. For example, when the main code is 2 and the sub code is 2, a data pattern of 2T mark-2T space is shown.

  The data pattern selection criterion is determined based on whether or not PRerror_ptn (p) calculated for the first time exceeds the second threshold. That is, in the present invention, in the second and subsequent evaluation index value calculation processes, a data pattern that is determined to be unsatisfactory by the first evaluation index value calculation process is selected, and the data pattern is used as a calculation target. In addition, as another selection criterion, it may be limited to only the top N (N is a natural number of 1 or more, for example, 3) from the low (high value) evaluation of PRerror_ptn (p). The value of N may be, for example, a total number that occupies 80% of the total, or may be selected and determined as appropriate according to the design specifications and capabilities of the recording / reproducing device.

  The ideal signal generation unit 530 generates a PR ideal signal at a command timing from the detection command unit 520 for a predetermined data pattern (for example, a pattern of space 3T, mark 4T, and space 3T) detected by the detection command unit 520.

  The evaluation index value calculation unit 550 is based on the PR ideal signal generated by the ideal signal generation unit 530 and the PR equalization signal from the PR equalizer 431 based on the equation (1). PRerror_ptn (p) is calculated at the command timing and stored in a predetermined memory. Here, as described above, it is preferable that the evaluation index value calculation unit 550 obtains a plurality of samples for one data pattern and calculates the average value of PRerror_ptn (p). Further, the evaluation index value calculation unit 550 calculates PRerror_ttl based on the calculated PRerror_ptn (p). Each calculated evaluation index value is sent to the recording compensation processing unit 330, and is used for correcting a write strategy parameter (for example, dTtop2T) in the recording compensation processing unit 330. Each calculated evaluation index value is output to another control unit of the optical information recording / reproducing apparatus 100, an external device, or the like.

  Next, a data recording evaluation method in the optical information recording / reproducing apparatus according to the present embodiment will be described in detail with reference to the flowchart of FIG. Here, prior to the actual recording of the user data, the evaluation index value calculation and the recording condition optimization process are performed using the test writing area provided in the innermost circumference of the optical disc 10, and then the actual recording of the user data is performed. The case will be described.

  As shown in FIG. 5, first, the optical disc 10 is inserted into the optical information recording / reproducing apparatus 100 (step S1). The control unit (not shown) reads disc information such as a media ID (step S2), and sets recording conditions (power, recording speed, initial strategy, etc.) in the recording compensation processing unit 330 (step S3). Next, the control unit sets all the data patterns as detection targets to the detection command unit 520 (step S4). Next, the control unit writes predetermined test data to the optical disc 10 (step S5), and then controls to read the recorded test data (step S6). During the reading process, the evaluation index value calculation unit 550 calculates PRerror_ptn (p) and PRerror_ttl (step S6). Next, the control unit determines the recording state based on the calculated evaluation index value (step S7). The determination of the recording state is determined based on PRerror_ttl when the evaluation index value is calculated for the first time, that is, when the evaluation index value is calculated for all data patterns. Specifically, when PRerror_ttl exceeds the first threshold, it is determined that the recording state is not good. On the other hand, when the evaluation index value is calculated for the second time or later, that is, when the evaluation index value is calculated using a data pattern selected by the processing described later as a calculation target, the evaluation index value is determined based on PRerror_ptn (p) of each data pattern. Specifically, when there is even one data pattern in which PRerror_ptn (p) exceeds the second threshold, it is determined that the recording state is not good.

  If it is determined that the recording state is not good, the control unit selects a data pattern in which PRerror_ptn (p) exceeds the second threshold value from all the data patterns, and sets only the data pattern as a detection target. The detection command unit 520 is set (step S8). Here, as described above, the second threshold value is calculated by multiplying the first threshold value by the contribution degree. In step S8, the top N items having the largest PRerror_ptn (p) may be selected from all data patterns. Next, the control unit corrects the recording condition in the recording compensation processing unit 330 (step S9). Next, control is performed so that predetermined test data is written to the optical disc 10 (step S10), and then the recorded test data is read (step S11). During the reading process, the evaluation index value calculation unit 550 calculates PRerror_ptn (p) and PRerror_ttl (step S6). Here, it should be noted that the calculation process is the second or subsequent calculation process, and as described above, the data pattern to be calculated is selected in step S8. Next, the control unit moves the process to step S7, and determines the recording state based on the calculated evaluation index value.

  When determining that the recording state is good, the control unit sets recording conditions for the main recording of the user data (step S12), and performs the main recording process of the user data (step S13). The recording conditions set in step S12 are the test data recording conditions when it is determined that the recording state is good. In this recording process, WOPC or ROPC (Running Optimum Power Control) is performed as necessary. When this recording process ends, the control unit ejects the optical disc 10 from the optical information recording / reproducing apparatus 100 as necessary.

  Depending on the quality, conditions, etc. of the optical disk 10, it may not be determined that the recording state is good no matter how much the recording state is corrected. In such a case, the processing may be interrupted because the disk is abnormal. Specifically, a limited number of times is provided in the evaluation process in step S7, and the process may be interrupted when the limit number is exceeded.

  As described above, according to the present invention, after the evaluation index value is calculated once, the data pattern to be calculated in the calculation process is selected based on the evaluation index value, so that the subsequent calculation process of the evaluation index value is accelerated. can do.

  Although one embodiment of the present invention has been described in detail above, the present invention is not limited to this. For example, in the above embodiment, the ideal signal generation unit 530 generates the PR ideal signal based on the output signal of the PRML processing unit 430, that is, the reproduction data. However, the ideal signal generation unit 530 may generate the PR ideal signal based on the recording data. Good.

  In the above embodiment, the process of recording / reproducing / evaluating the test data is performed every time the recording conditions are corrected (steps S9, S10, S11, S7). In step S9, a plurality of recording conditions are determined. In step S10, test data may be recorded under each recording condition, and an evaluation index value may be calculated for each recording condition in step S11. In this case, in step S12, the recording condition relating to the test recording determined to be good may be set as the recording condition in the main recording.

  In the above embodiment, the second and subsequent recording states are determined based on PRerror_ptn (p) of the selected data pattern. However, PRerror_ttl is calculated from PRerror_ptn (p) and based on PRerror_ttl. The recording state may be determined.

  In the above embodiment, WOPC or ROPC is used as necessary during the main recording process of user data. However, the present invention can also be applied to the WOPC process.

  In the above embodiment, the PR (1, 2, 2, 1) characteristic is exemplified. However, for example, other PR characteristics such as PR (1, 2, 2, 2, 1) used in the HD-DVD standard or the like are used. Even if it exists, this invention can be implemented. In the above embodiment, the optical disk 10 is exemplified as a medium in which the reflected light amount at the mark portion is larger than the reflected light amount at the space portion. However, the reflected light amount at the mark portion is smaller than the reflected light amount at the space portion. It may be media.

  DESCRIPTION OF SYMBOLS 10 ... Optical disk, 100 ... Optical information recording / reproducing apparatus, 200 ... Optical pick-up, 300 ... Recording system apparatus, 330 ... Recording compensation process part, 400 ... Reproduction system apparatus, 430 ... PRML process part, 431 ... PR equalizer, 432 ... Viterbi decoder 500 ... Evaluation device 510 ... Code identification unit 520 ... Detection command unit 530 ... Ideal signal generation unit 540 ... Delay unit 550 ... Evaluation index value calculation unit

Claims (24)

In an optical information recording / reproducing system for recording / reproducing information by irradiating an optical information recording medium with laser light,
A reproduction signal detection step of detecting a reproduction signal from the reflected light of the laser beam irradiated on the optical information recording medium;
A PRML processing step of detecting playback data from the playback signal by PRML (Partial Response Maximum Likelihood) signal processing;
For a predetermined data pattern included in the reproduction data, the first evaluation index value is assigned to each data based on the reproduction signal after PR processing corresponding to the data pattern and the ideal signal of the reproduction signal after PR processing corresponding to the data pattern. A first evaluation index value calculating step for calculating for each pattern;
A second evaluation index value calculating step of calculating a second evaluation index value based on the first evaluation index value of each data pattern and the appearance probability of the data pattern;
A determination step of determining pass / fail of the recording state based on one or both of the first evaluation index value and the second evaluation index value;
A data pattern for selecting a data pattern to be calculated in the evaluation index value calculation step based on the calculated first evaluation index value for each data pattern when it is determined in the determination step that the recording state is not good A selection step;
A data recording evaluation method comprising: a resetting step of resetting the selected data pattern as a calculation target in the evaluation index value calculating step. The first evaluation index value calculating step includes a step of calculating a value obtained by quantifying a distance between a reproduction signal after PR processing and an ideal signal for each data pattern. Data recording evaluation method. The first evaluation index value calculating step includes a step of calculating an average value of values obtained by quantifying the distance between the reproduction signal after the plurality of PR processes and the ideal signal for each data pattern. The data recording evaluation method according to claim 2. In the second evaluation index value calculation step, a second evaluation index value is obtained by taking a sum of all data patterns obtained by multiplying the first evaluation index value of each data pattern by the appearance probability of the data pattern. The data recording evaluation method according to claim 1, wherein the data recording evaluation method is calculated. The data recording evaluation method according to claim 4, wherein, in the determination step, it is determined that the recording state is not good when the second evaluation index value exceeds the first threshold value. 6. The data recording evaluation according to claim 5, wherein in the data pattern selection step, a data pattern having a first evaluation index value exceeding a second threshold is selected as a calculation target in the evaluation index value calculation step. Method. 6. The data recording according to claim 5, wherein, in the data pattern selection step, the top N data patterns (N is a natural number of 1 or more) having a low evaluation of the first evaluation index value are selected as calculation targets. Evaluation methods. The data recording evaluation method according to claim 6, wherein the second threshold value is calculated by multiplying the first threshold value by a predetermined constant (contribution). Correction for correcting a write strategy parameter at the time of data recording based on one or both of the first evaluation index value and the second evaluation index value when it is determined that the recording state is not good in the determination step The data recording evaluation method according to claim 1, further comprising a step. The method includes: reading at least one of the first threshold value, the second threshold value, the degree of contribution, and a value necessary for calculating these values from an optical recording medium. The data recording evaluation method according to any one of the preceding claims. In an optical information recording / reproducing system for recording / reproducing information by irradiating an optical information recording medium with laser light,
Reproduction signal detection means for detecting a reproduction signal from the reflected light of the laser beam irradiated on the optical information recording medium;
PRML processing means for detecting reproduction data from the reproduction signal by PRML (Partial Response Maximum Likelihood) signal processing;
For a predetermined data pattern included in the reproduction data, the first evaluation index value is assigned to each data based on the reproduction signal after PR processing corresponding to the data pattern and the ideal signal of the reproduction signal after PR processing corresponding to the data pattern. First evaluation index value calculating means for calculating for each pattern;
Second evaluation index value calculating means for calculating a second evaluation index value based on the first evaluation index value of each data pattern and the appearance probability of the data pattern;
Determination means for determining the quality of the recording state based on one or both of the first evaluation index value and the second evaluation index value;
A data pattern for selecting a data pattern to be calculated in the evaluation index value calculation step based on the calculated first evaluation index value for each data pattern when it is determined in the determination step that the recording state is not good A selection means;
A data record evaluation apparatus comprising: resetting means for resetting a selected data pattern as a calculation target in the evaluation index value calculation step. The data recording evaluation apparatus according to claim 11, wherein the first evaluation index value calculation means calculates a value obtained by quantifying the distance between the reproduction signal after PR processing and the ideal signal for each data pattern. . 13. The first evaluation index value calculation unit calculates an average value of values obtained by quantifying the distances between a plurality of PR-processed reproduction signals and ideal signals for each data pattern. Data record evaluation device. The second evaluation index value calculating means calculates the second evaluation index value by taking the sum of all data patterns obtained by multiplying the first evaluation index value of each data pattern by the appearance probability of the data pattern. The data recording evaluation apparatus according to any one of claims 11 to 13, wherein the data recording evaluation apparatus calculates. The data recording evaluation apparatus according to claim 14, wherein the determination unit determines that the recording state is not good when the second evaluation index value exceeds the first threshold value. The data record evaluation device according to claim 15, wherein the data pattern selection unit selects a data pattern having a first evaluation index value exceeding a second threshold as a calculation target in the evaluation index value calculation step. . 16. The data recording according to claim 15, wherein the data pattern selection unit selects, as calculation targets, the top N (N is a natural number of 1 or more) data patterns having a low evaluation of the first evaluation index value. Evaluation device. The data recording evaluation apparatus according to claim 16 or 17, wherein the second threshold value is calculated by multiplying the first threshold value by a predetermined constant (contribution). Correction for correcting a write strategy parameter at the time of data recording based on one or both of the first evaluation index value and the second evaluation index value when the determination unit determines that the recording state is not good The data recording evaluation apparatus according to claim 11, further comprising: means. The first threshold value, the second threshold value, the degree of contribution, or means for reading out at least one of these values from the optical recording medium is included. Data recording evaluation apparatus according to item.   A data recording evaluation program for causing a processor to execute the data recording evaluation method according to any one of claims 1 to 10.   22. A processor comprising a memory storing the data recording evaluation program according to claim 21.   6. An optical information recording medium on which the first threshold value according to claim 5 is recorded.   An optical information recording medium on which the second threshold value according to claim 6 is recorded.

Images