JP2013062000A - Optical disk recording and reproducing device - Google Patents

Abstract

An object of the present invention is to shorten start-up time and improve recording quality.
A recording / reproducing unit (11) converts recording data into a recording pulse (WP) based on a recording parameter, and forms a recording area on the optical disc (10) based on the recording pulse (WP). The reproduction operation for generating the analog reproduction signal (AS) based on the recording area formed on the optical disc (10) by the recording operation is alternately repeated. The reproduction processing unit (12) converts the analog reproduction signal (AS) into a digital reproduction signal (DS). The decoding processing unit (13) performs a maximum likelihood decoding process on the digital reproduction signal (DS) to generate a binary signal (D302). The quality information detector (14) detects a reliability value for each edge pattern of the binarized signal (D302). The control unit (15) adjusts the recording parameter based on the reliability value detected for each edge pattern.
[Selection] Figure 1

Description

  The present invention relates to an optical disc recording / reproducing apparatus, and more particularly to a technique for adjusting a recording pulse based on a recording quality evaluation result.

  Conventionally, in an optical disk recording / reproducing apparatus, in order to suppress deterioration in recording quality due to individual differences between optical disks and apparatuses (such as lot variations at the time of manufacturing optical disks, wavelength variations of laser light in optical heads, and sensitivity variations of light receiving elements). A calibration operation (optimization of recording power and optimization of the shape of a recording pulse) is performed when an optical disk is attached or detached. As techniques for optimizing the shape of the recording pulse, Patent Documents 1, 2, 3 and the like are known. Patent Document 1 describes a technique for optimizing the shape of a recording pulse so that the error probability in maximum likelihood decoding is minimized. Patent Document 2 describes a technique for optimizing the shape of a recording pulse corresponding to the shortest recording mark so that reproduced signal quality (jitter and error probability) is improved. Patent Document 3 describes a technique for optimizing the shape of a recording pulse so that the length error value and phase error value of a recording mark become target values other than “0”.

JP 2004-335079 A JP 2004-213865 A JP 2007-280492 A

  However, the techniques described in Patent Documents 1, 2, and 3 are provided on the inner peripheral portion or the outer peripheral portion of the optical disc based on the recording pulse corresponding to the test pattern prepared for the optimization of the recording pulse. Since the recording mark corresponding to the test pattern is formed in the power calibration area (PCA) and the shape of the recording pulse is optimized based on the recording quality of the recording mark formed in the power calibration area, power calibration After the recording pulse optimization processing in the area is completed, recording processing of recording data (for example, user data) to be recorded on the optical disc is executed. For this reason, the activation time (time until recording of recording data is started) becomes long.

  In addition, when the recording mark formation conditions (for example, linear velocity and physical characteristics) are different for each area of the optical disk, even if the shape of the recording pulse is optimized in the power calibration area, the shape of the recording pulse is It may not be optimal for other areas. Therefore, the recording quality is deteriorated (the error probability in the maximum likelihood decoding process is increased).

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical disc recording / reproducing apparatus capable of reducing the startup time and improving the recording quality.

  According to one aspect of the present invention, an optical disk recording / reproducing apparatus records a predetermined amount of data to be recorded on an optical disk based on a recording parameter indicating a correspondence relationship between the length of a mark section of recording data and the shape of a recording pulse. A recording operation for converting data into recording pulses and irradiating a recording beam on the data area of the optical disc based on the recording pulses to form a recording area composed of a plurality of marks and spaces in the data area, and by the recording operation A recording / playback unit that alternately repeats a playback operation for generating an analog playback signal by irradiating a playback beam to the recording area formed in the data region, and a playback processing unit for converting the analog playback signal into a digital playback signal; A decoding processor that performs maximum likelihood decoding on the digital reproduction signal to generate a most likely binary signal; and An edge pattern expressed by a combination of a mark section and a space section of the binary signal adjacent to each other with the transition edge interposed is detected for each transition edge of the binary signal, and the edge pattern corresponds to the edge pattern A quality information detection unit for detecting a reliability value indicating the reliability of the result of the maximum likelihood decoding process, and a period from the start of the reproduction operation by the recording / reproduction unit to the start of the recording operation by the recording / reproduction unit, And a control unit that adjusts the shape of the recording pulse indicated by the recording parameter based on the reliability value detected for each edge pattern. In the optical disk recording / reproducing apparatus, a recording process for recording a predetermined amount of recording data, a verification process for adjusting the shape of the recording pulse indicated by the recording parameter based on the recording quality of the predetermined amount of recording data recorded on the optical disk, The write-and-verify operation that alternately repeats the start-up time (time until recording of recording data to be recorded on the optical disk) can be shortened, and the recording quality can be improved (in the maximum likelihood decoding process) Error probability can be reduced).

  The optical disc recording / reproducing apparatus further includes an information storage unit that stores a plurality of recording parameters corresponding to different recording conditions, and the control unit includes a plurality of recording parameters stored in the information storage unit. Select a recording parameter corresponding to the current recording condition from, adjust the shape of the recording pulse indicated in the recording parameter corresponding to the current recording condition based on the reliability value detected for each edge pattern, The recording / reproducing unit may perform the recording operation based on the recording parameter selected by the control unit. In the above optical disc recording / reproducing apparatus, the recording parameters processed by the write and verify operation can be managed for each recording condition, so even if the recording condition is changed during the write and verify operation, the change is made. It is possible to save the recording parameters adjusted under the previous recording conditions. Thereby, the recording parameter can be optimized for each recording condition.

  Further, the control unit, based on the reliability value detected for each of the edge patterns, the mark section of the binarized signal and two space sections of the binarized signal adjacent to each other with the mark section interposed therebetween An error value of the recording pattern is calculated for each recording pattern expressed by the combination, and the recording parameter is set so that at least one error value among the error values calculated for each recording pattern approaches a preset target value. The shape of the recording pulse shown in FIG. With this configuration, the recording quality can be improved.

  Further, the control unit determines whether a difference value between the error value and the target value is larger than an improvement reference value for each recording pattern, and determines that the difference value is larger than the improvement reference value. The shape of the recording pulse indicated by the recording parameter may be adjusted so that the error value of at least one recording pattern of the recorded patterns approaches the target value. With this configuration, the recording quality can be improved so that the error value becomes smaller than the improvement reference value.

  Further, the control unit determines whether or not a difference value between the error value and the target value is larger than a defect reference value for each recording pattern, and the recording pattern has a difference value larger than the defect reference value. The recording / reproducing is performed so that a predetermined amount of recording data recorded by the previous recording operation by the recording / reproducing unit is re-recorded in the alternate sector of the optical disc by the next recording operation by the recording / reproducing unit. The defect reference value may be larger than the improvement reference value. With this configuration, recorded data that cannot be normally reproduced due to poor quality can be relieved.

  The optical disc recording / reproducing apparatus further includes an information storage unit for storing a plurality of recording parameters corresponding to different recording conditions and a plurality of target values corresponding to different recording conditions, and the control unit includes: Selecting a recording parameter and a target value corresponding to the current recording condition from a plurality of recording parameters and a plurality of target values stored in the information storage unit, and at least an error value calculated for each recording pattern The pulse shape of the recording pulse indicated by the recording parameter corresponding to the current recording condition is adjusted so that one approaches the target value corresponding to the current recording condition, and the recording / reproducing unit is selected by the control unit The recording operation may be executed based on the recorded parameters. In the optical disc recording / reproducing apparatus, since the target value can be set accurately for each recording condition, the optimality of the recording parameters can be improved.

  The control unit instructs the quality information detection unit to transfer the reliability value of the edge pattern to be used for the adjustment of the recording parameter among the reliability values detected for each edge pattern, The quality information detection unit may transfer the reliability value of the edge pattern specified by the control unit among the reliability values detected for each edge pattern to the control unit. With this configuration, the time required for the transfer process between the quality information detection unit and the control unit can be shortened, so that the period from the start of the reproduction operation by the recording / reproduction unit to the start of the recording operation by the recording / reproduction unit This completes the adjustment of the recording parameters.

  In addition, the quality information detection unit is the second most reliable by the first index value indicating the likelihood of the first state transition sequence determined to be most likely by the maximum likelihood decoding process and the maximum likelihood decoding process. A second index value indicating the likelihood of the second state transition sequence determined to be correct, and the reliability value is calculated based on a difference value between the first and second index values. The edge pattern detection unit detects the edge pattern for each transition edge of the binarized signal, and the edge pattern detection unit detects the reliability value calculated by the reliability calculation unit. And a reliability storage unit that stores the edge patterns in association with each other. With this configuration, the reliability value can be detected for each edge pattern.

  As described above, the start-up time can be shortened and the recording quality can be improved.

The figure which shows the structural example of an optical disk recording / reproducing apparatus. FIG. 6 is a state transition diagram determined from a recording code having a minimum polarity inversion interval of 2 and an equalization method PR (1, 2, 2, 1). FIG. 5 is a trellis diagram determined from a recording code having a minimum polarity inversion interval of 2 and an equalization method PR (1, 2, 2, 1). The distribution diagram of the reliability value which showed the reliability of the result of maximum likelihood decoding. The figure which showed the expected value series of pattern PP1-PP8. The figure for demonstrating the correspondence of pattern PP1-PP8 and an edge pattern (edge part of a recording mark). The figure for demonstrating an edge shift value. The figure for demonstrating an edge shift value. The figure for demonstrating the recording pattern used as the calculation object of a length error value and a phase error value. The figure for demonstrating a length error value and a phase error value. The figure for demonstrating the shape of a recording pulse. The figure for demonstrating the correspondence of the adjustment amount of the shape of a recording pulse, and the variation | change_quantity of the length of a recording mark. The figure for demonstrating the correspondence of the adjustment amount of the shape of a recording pulse, and the variation | change_quantity of a length error value. The figure for demonstrating the correspondence of the adjustment amount of the shape of a recording pulse, and the variation | change_quantity of the phase of a recording mark. The figure for demonstrating the correspondence of the adjustment amount of the shape of a recording pulse, and the variation | change_quantity of a phase error value. The figure for demonstrating the structure of an optical disk. The figure for demonstrating the recording parameter set to a recording / reproducing part. The figure for demonstrating the process by a recording / reproducing part, a reproduction | regeneration processing part, and a decoding process part. The figure for demonstrating the process by a reliability calculation part. The figure for demonstrating the process by an edge pattern detection part. The figure for demonstrating the process by a quality information detection part. The figure for demonstrating the reliability value stored in a reliability storage part. The figure for demonstrating the structure of recording setting information. The figure for demonstrating the structure of quality control information. The figure for demonstrating the structure of target setting information. The figure for demonstrating the write-and-verify operation | movement by an optical disk recording / reproducing apparatus. The figure for demonstrating a recording parameter control process. The figure for demonstrating shortening of starting time. The figure for demonstrating the improvement of recording quality. The figure for demonstrating a jitter detection process. The figure which shows the structural example of a clock generator. The figure for demonstrating the length error value and phase error value in the case of jitter optimization. The figure for demonstrating the modification of a clock generator. The figure for demonstrating the process by the clock generator shown in FIG.

  Hereinafter, embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

  FIG. 1 shows a configuration example of an optical disc recording / reproducing apparatus. This apparatus includes a recording / playback unit 11, a playback processing unit 12, a decoding processing unit 13, a quality information detection unit 14, a controller 15 (control unit), and an information storage unit 16. Here, it is assumed that the optical disc 10 is a BD-RE (Blu-ray Disc Rewritable).

  The recording / reproducing unit 11 alternately repeats the recording operation and the reproducing operation in response to the control by the controller 15. In the case of a recording operation, the recording / reproducing unit 11 converts the recording data WD into a recording pulse WP based on the recording parameter, and irradiates the data area of the optical disc 10 with a recording beam based on the recording pulse WP. A recording area (an area composed of a plurality of recording marks and spaces) is formed in the data area. The recording parameter indicates the correspondence between the length of the mark section of the recording data WD (for example, the section in which bit values indicating 1 are continuous) and the shape of the recording pulse WP. In the case of a reproduction operation, the recording / reproducing unit 11 generates an analog reproduction signal AS by irradiating a reproduction beam to a recording area formed in the data area of the optical disc 10 by the recording operation.

  The reproduction processing unit 12 converts the analog reproduction signal AS generated by the reproduction operation of the recording / reproducing unit 11 into a digital reproduction signal DS. The frequency characteristic of the digital reproduction signal DS may have a predetermined equalization characteristic (for example, PR (1, 2, 2, 1) equalization characteristic).

  The decoding processing unit 13 performs maximum likelihood decoding processing on the digital reproduction signal DS obtained by the reproduction processing unit 12 to generate the most likely binary signal D302. In the binarized signal D302, a mark section (for example, a section where bit values indicating 0 continue) and a space section (for example, a bit value indicating 1) corresponding to the recording mark and space formed on the optical disc 10 respectively. (Continuous sections) are alternately repeated, and the mark section and the space section are adjacent to each other across the transition edge of the binarized signal D302.

  The quality information detection unit 14 detects an edge pattern for each transition edge of the binarized signal D302. The edge pattern is a bit pattern expressed by a combination of a mark section and a space section of the binarized signal D302 adjacent to each other with the transition edge of the binarized signal D302 interposed therebetween. Moreover, the quality information detection part 14 detects a reliability value for every edge pattern. The reliability value is an index value (for example, SAM (Sequence Amplitude Margin) or MLSE (Maximum Likelihood Sequence Error)) indicating the reliability of the result of the maximum likelihood decoding process corresponding to the edge pattern.

  Based on the reliability value detected for each edge pattern by the quality information detection unit 14 in the period from the start of the reproduction operation by the recording / reproduction unit 11 to the start of the recording operation by the recording / reproduction unit 11, the controller 15 The shape of the recording pulse WD shown in FIG. For example, the controller 15 calculates an error value (length error value and / or phase error value) for each recording pattern based on the reliability value detected for each edge pattern, and the error calculated for each recording pattern. The recording parameter is adjusted so that at least one error value of the values approaches a target value (length target value and / or phase error value). The recording pattern is a bit pattern expressed by a combination of a mark section of the binarized signal D302 and two space sections adjacent to each other with the mark section interposed therebetween. The length error value is a value indicating the difference between the length of the recording mark formed in the data area of the optical disc 10 and the ideal length of the recording mark, and the phase error value is the data of the optical disc 10. This is a value indicating the difference between the phase (center position) of the recording mark formed in the area and the phase (center position) of the ideal recording mark.

(Optimization of recording pulses suitable for maximum likelihood decoding)
Here, with reference to FIG. 2 to FIG. 15, a method for adjusting the shape of the recording pulse so as to reduce the error probability in the maximum likelihood decoding process will be described in detail.

[Maximum likelihood decoding method, reproduction signal quality evaluation method]
First, a maximum likelihood decoding method and a reproduction signal quality evaluation method will be described with reference to FIGS. Here, the reproduction polarity reversal interval of the recording code (recording data WD) is “2”, and the frequency characteristics of the signal during recording and reproduction are PR (1, 2, 2, 1) equalization characteristics. A case where the signal waveform is shaped will be described as an example. The recording code at the current time is b _k , the recording code one hour before is b _k−1 , the recording code two hours before is b _k−2, and the recording code three times before is b _k−3 . The ideal output value Level _v (expected value) of PR (1, 2, 2, 1) equalization is expressed as (Equation 1).

Here, k is an integer representing time, and v is an integer from 0 to 6. If the state at time k is S (b _k−2 , b _k−1 , b _k ), the state transition table of Table 1 is obtained.

For simplicity of explanation, at time k, state S (0,0,0) _{k is set} to S0 _k , state S (0,0,1) _{k is set} to S1 _k ,
State S (0,1,1) _k is S2 _k , State S (1,1,1) _k is S3 _k ,
State S (1,1,0) _k is S4 _k , State S (1,0,0) _k is S5 _k ,
Then, the state transition diagram shown in FIG. 2 is obtained. The state transition diagram shown in FIG. 2 represents a state transition rule determined from a recording code having a minimum polarity inversion interval of 2 and an equalization method PR (1, 2, 2, 1). 2 is developed along the time axis, the trellis diagram shown in FIG. 3 is obtained.

3, when attention is paid to the state S0 _k and time k-4 states _{S2 k-4} at time k, that two state transition sequence exists between the state S0 _k and state _{S2 k-4} Recognize. Here, the state transition sequence that transitions in the order of the states S2 _k-4 , S4 _k-3 , S5 _k-2 , S0 _k-1 , S0 _k is “path A”, and the states S2 _k-4 , S3 _{k− 3} , a state transition sequence that transitions in the order of S4 _k-2 , S5 _k-1 , S0 _k is _defined as “path B”. The decoded data (binarized signal D302) from time k-6 to time k obtained by the maximum likelihood decoding process is expressed as (C _k-6 , C _k-5 , C _k-4 , C _k-3 , C _{k- 2} , C _k−1 , C _k ), (C _k−6 , C _k−5 , C _k−4 , C _k−3 , C _k−2 , C _k−1 , C _k ) = (0 , 1, 1, x, 0, 0, 0) (x is 0 or 1), the path A or the path B is estimated as the most probable state transition sequence. Since both the path A and the path B have the same probability of the state S2 _{k-4 at} the time k-4, each sample value of the reproduction signal at the time k-3 to the time k for each of the path A and the path B. A path A is obtained by calculating a cumulative value (sum of squared differences) of values obtained by squaring the difference between (y _k−3 , y _k−2 , y _k−1 , y _k ) and each expected value of the state transition sequence. It is possible to discriminate which of the path transition path and the path B is likely. The difference sum of squares between each sample value of the reproduction signal from time k-3 to time k and each expected value of path A is defined as “index value Pa”, and each sample of the reproduction signal from time k-3 to time k When the difference square sum value between the value and each expected value of the path B is “index value Pb”, the index values Pa and Pb are expressed as (Equation 2) and (Equation 3), respectively.

  In the maximum likelihood decoding process, when Pa << Pb (when the index value Pa is sufficiently smaller than the index value Pb), the path A is selected as the most probable state transition sequence, and Pa >> Pb In the case where the index value Pa is sufficiently larger than the index value Pb, the path B is selected as the most likely state transition sequence. Further, when Pa = Pb, it does not matter which of path A and path B is selected as the most probable state transition sequence, and whether the result of the maximum likelihood decoding process is correct is 5 minutes 5 minutes.

  Here, assuming that the difference value (Pa−Pb) between the index values Pa and Pb is “reliability value”, the maximum likelihood decoding process is performed as the absolute value (| Pa−Pb |) of the reliability value is larger than 0. It can be judged that the reliability of the result is high. The reliability value (Pa-Pb) can be used to predict the error probability of the decoded data obtained by the maximum likelihood decoding process. For example, when the maximum likelihood decoding process is repeatedly executed for a predetermined time or a predetermined number of times to calculate the reliability value, a distribution of reliability values (Pa−Pb) as shown in FIG. 4A is obtained. FIG. 4A shows the distribution of reliability values when noise is superimposed on the reproduction signal. This distribution has two peaks, one having a maximum when Pa = 0, and the other having a maximum when Pb = 0. The reliability value (Pa−Pb) when Pa = 0 is “−Pstd”, the reliability value (Pa−Pb) when Pb = 0 is “Pstd”, and the absolute value (| When Pa−Pb |) is calculated and | Pa−Pb | −Pstd is calculated, a distribution as shown in FIG. 4B is obtained. Then, the standard deviation value σ and the average value Pave are obtained in the distribution of | Pa−Pb | −Pstd shown in FIG. Here, if the distribution of FIG. 4B is a normal distribution and the absolute value (| Pa−Pb |) of the reliability value is equal to or less than “−Pstd”, the standard deviation value is assumed. Based on σ and the average value Pave, the error probability P (σ, Pave) can be expressed as (Equation 4).

  Based on the average value Pave calculated from the distribution of reliability values (Pa−Pb) and the standard deviation σ, the error probability of the decoded data output according to the result of the maximum likelihood decoding process is predicted by (Expression 4) can do. That is, the average value Pave and the standard deviation σ can be used as an index of reproduction signal quality. Note that the case where the distribution of reliability values (Pa−Pb) is a normal distribution has been described as an example. However, when the distribution of reliability values (Pa−Pb) is not a normal distribution, | Pa−Pb | It is also possible to count the number of times −Pstd becomes equal to or less than a predetermined reference value, and use the counted number as an indicator of signal quality.

  As described above, the reliability value (Pa-Pb) can be used as an index of the reproduction signal quality. When the minimum polarity reversal interval of the recording code is “2” and the equalization method is PR (1, 2, 2, 1), the time k−n is the same as the combination of the path A and the path B described above. The combination of two state transition sequences having the same state at time k (n is an integer equal to or greater than 1) and the state at time k is 8 in the range from time k-4 to time k (when n = 4). There are pairs. When the time range is expanded (when n> 4), there are the same number of combinations as the reliability value (Pa−Pb). Note that not all combinations are subject to calculation of reliability values, but only combinations that have a relatively high possibility of error (combinations with relatively small reliability values) may be subject to calculation of reliability values. Thus, even when the reliability value is calculated, it is possible to obtain an index having a correlation with the error probability. For example, eight combinations of Pa−Pb = ± 10 may be calculated as reliability values. Table 2 shows the correspondence between these eight combinations and the reliability value (Pa-Pb).

  If the combinations shown in Table 2 are the patterns PP1, PP2,..., PP8 in order from the top, the reliability values of the patterns PP1 to PP8 can be calculated as shown in (Equation 5). .

^{_{However, A k = (y k -0}} ) 2, B k = (y k -1) 2, C k = (y k -2) 2,
D _k = (y _k −3) ² , E _k = (y _k −4) ² , F _k = (y _k −5) ² ,
G _k = (y _k −6) ²
It is.

Based on (Equation 5), the decoded data (c _k-6 , c _k-5 , c _k−4 , c _k−3 , c _k−2 , c _k−1 , c) obtained by the maximum likelihood decoding process. _The reliability value (Pa−Pb) can be calculated from _k ). Further, assuming that the distribution of reliability values (Pa−Pb) is a normal distribution, the standard deviation σ ₁₀ and the average value Pave ₁₀ are calculated. Based on the standard deviation value σ ₁₀ and the average value Pave ₁₀ , The error probability P ₁₀ (σ ₁₀ , Pave ₁₀ ) can be expressed as (Equation 6).

Patterns PP1 to PP8 correspond to combinations of state transition sequences in which a 1-bit shift error may occur, and other state transition sequences other than patterns PP1 to PP8 may generate a bit shift error of 2 bits or more. It is a characteristic state transition sequence. Further, when the error pattern after the PRML process is analyzed, since most errors are 1-bit shift errors, the error probability P ₁₀ (σ ₁₀ , Pave ₁₀ ) is calculated based on (Equation 6). The error probability can be accurately estimated.

[Pattern PP1 to PP8]
Next, the patterns PP1 to PP8 will be described with reference to FIGS. 5 (a) to 5 (h) and FIG. Figure 5 (a) ~ FIG 5 (h) shows the expected sequence pattern PP1～PP8 (expected value Level _v at each time k-. 4 to time k). In the figure, the horizontal axis indicates time (one scale corresponds to the channel clock cycle TCLK), the vertical axis indicates the signal level (0 to 6), the dotted line indicates the path A, and the solid line indicates the path B. Is shown.

  The expected value series of the state transition sequences (path A and path B) of the patterns PP1 to PP8 is a reproduction corresponding to the boundary part (starting edge part and ending edge part of the recording mark) between the recording mark and the space formed on the optical disk. It shows the ideal waveform of the signal. The patterns PP1 to PP4 correspond to the start edge portion of the recording mark, and the patterns PP5 to PP8 correspond to the end edge portion of the recording mark. The patterns PP1 to PP4 correspond to the start edge pattern of the decoded data (binary signal D302) obtained by the maximum likelihood decoding process, and the patterns PP5 to PP8 correspond to the end edge pattern of the decoded data. It can be said. A start edge pattern is a bit pattern expressed by a combination of a mark section of decoded data and a space section located immediately before the mark section. A terminal edge pattern is a mark section of decoded data and its mark. It is a bit pattern expressed by a combination with a space section located immediately after the section.

  Each of the patterns PP1 to PP8 is a combination of two state transition sequences that have a relatively high possibility of error. Therefore, the recording quality can be improved by adjusting the positions of the edge portions (start edge portion and end edge portion) of the recording mark formed on the optical disc so that the reliability value calculated based on the patterns PP1 to PP8 is high. It is possible to improve (the error probability in the maximum likelihood decoding process can be reduced).

  FIG. 6 shows the correspondence between the patterns PP1 to PP8 and the edge portion of the recording mark (the edge pattern of the decoded data). In the drawing, “2Tm”, “3Tm”, “4Tm”, and “5Tm or more” indicate that the length of the recording mark formed on the optical disc (the length of the mark section of the decoded data) is 2T (shortest mark length). , 3T, 4T, 5T or more (5T mark length to longest mark length), and “2Ts”, “3Ts”, “4Ts”, “5Ts or more” are the lengths of the spaces formed on the optical disc, respectively. The length (the length of the space section of the decoded data) is 2T (shortest space length), 3T, 4T, 5T or more (5T space length to longest space length). Further, “P1A”, “P2A”,..., “P8A” indicate the paths A of the patterns PP1, PP2,..., PP8, respectively, and “P1B”, “P2B”,. The paths B of the patterns PP1, PP2,..., PP8 are shown. For example, the path A (P3A) of the pattern PP3 has a start edge portion (start edge pattern 2Ts3Tm) in which the length of the recording mark is “3T” and the length of the space located immediately before the recording mark is “2T”. It corresponds to.

  In all of the patterns PP1 to PP8, the start edge pattern 2Ts2Tm (the start edge portion where the length of each of the recording mark and the immediately preceding space is “2T”) and the end edge pattern 2Tm2Ts (the length of each of the recording mark and the immediately following space) Does not correspond to a terminal edge portion having a length of “2T”. Since the reliability value (Pa-Pb) of the state transition sequence corresponding to these edge patterns is larger than the reliability value of the state transition sequence corresponding to other edge patterns, the reliability corresponding to the edge patterns 2Ts2Tm and 2Tm2Ts Even if the position of the edge portion of the recording mark formed on the optical disk is not strictly adjusted based on the value, it may be considered that the error probability of the decoded data is difficult to increase.

[Calculation method of edge shift value]
Next, a method for calculating an edge shift value will be described in detail with reference to FIGS. The edge shift value is a value indicating a difference between an ideal edge position of the recording mark and an edge position of the recording mark formed on the optical disc. Here, the pattern PP1 is taken as an example, and in the figure, the triangle mark indicates the sample value of the reproduction signal, and the black circle mark connected by the dotted line indicates the expected value series of the path A of the pattern PP1 and is connected by the solid line. The black circles indicate the expected value series of the path B of the pattern PP1.

FIG. 7A shows that the starting edge position of the recording mark MB1 formed on the optical disc is shifted backward from the ideal starting edge position of the recording mark MA1, and the sample value (y _k−3 , y of the reproduction signal). _{In this example, k-2} , _yk-1 , _yk ) is (4.2, 3.2, 1.2, 0.2). The reproduction signal is generated based on the recording mark MB1. In this case, the path A of the pattern PP1 is selected as the most probable state transition sequence. Further, the index values Pa and Pb of the path A and the path B are calculated as in (Expression 7) and (Expression 8).

  Here, when the value (| Pa−Pb | −Pstd) obtained by subtracting the standard value (Pstd) from the absolute value of the reliability value is the edge shift value E1, the edge shift value E1 is expressed by (Equation 9). Is calculated as follows.

FIG. 7B shows that the start edge position of the recording mark MB1 formed on the optical disc is shifted forward from the ideal start edge position of the recording mark MA1, and the sample value (y _k−3 , y of the reproduction signal). _{In this case, k-2} , _yk-1 , _yk ) is (3.8, 2.8, 0.8, -0.2). Also in this case, the path A of the pattern PP1 is selected as the most probable state transition sequence, and the edge shift value E2 is calculated as “2.4”.

  As described above, the absolute value of the edge shift value indicates the shift amount of the edge position of the recording mark MB1 formed on the optical disc with respect to the ideal edge position of the recording mark MA1, and the sign of the edge shift value is the ideal value. The deviation direction of the edge position of the recording mark MB1 formed on the optical disc with respect to the edge position of the recording mark MA1 is shown. Therefore, in the case of FIG. 7A, referring to the edge shift value E1, the starting edge position of the recording mark MB1 formed on the optical disc is only “2.4” than the ideal starting edge position of the recording mark MA1. In the case of FIG. 7B, the start edge position of the recording mark MB1 formed on the optical disc is more than the ideal start edge position of the recording mark MA1 in the case of FIG. 7B with reference to the edge shift value E2. It can also be judged that it has shifted forward by “2.4”.

FIG. 8A shows that the starting edge position of the recording mark MB1 formed on the optical disc is shifted backward from the ideal starting edge position of the recording mark MA1, and the sample value (y _k−3 , y of the reproduction signal). _{In this example, k-2} , _yk-1 , _yk ) is (5.2, 5.2, 3.2, 1.2). In this case, the path B of the pattern PP1 is selected as the most probable state transition sequence, and the edge shift value E3 is calculated as “2.4”.

FIG. 8B shows that the starting edge position of the recording mark MB1 formed on the optical disc is shifted forward from the ideal starting edge position of the recording mark MA1, and the sample value of the reproduction signal is the sample value (y _{k− 3} , y _k−2 , y _k−1 , y _k ) is (4.8, 4.8, 2.8, 0.8). Also in this case, the path B of the pattern PP1 is selected as the most probable state transition sequence, and the edge shift value E4 is calculated as “−2.4”.

  As described above, the path A is selected as the most probable state transition sequence as shown in FIGS. 7A and 7B, and the path as shown in FIGS. 8A and 8B. In the case where B is selected as the most probable state transition sequence, the correspondence relationship between the shift direction of the edge position and the sign of the edge shift value is different. This is a sample of the expected value series and the reproduced signal of the state transition sequence determined to be the most probable and the state transition sequence not determined to be the most probable (the state transition sequence determined to be the second most probable). Depends on the relationship with the value series. For example, as shown in FIG. 7B and FIG. 8A, the sum of squared differences between each sample value of the reproduction signal and each expected value of the state transition sequence determined to be the second most likely is the standard value (Pstd The edge shift value has a positive sign. In consideration of such characteristics, the shift direction of the start edge position of the recording mark may be detected. Therefore, in the case of FIG. 8A, referring to the edge shift value E3, the starting edge position of the recording mark MB1 formed on the optical disc is “2.4” more than the ideal starting edge position of the recording mark MA1. In the case of FIG. 8B, the start edge position of the recording mark MB1 formed on the optical disc is more than the ideal start edge position of the recording mark MA1 with reference to the edge shift value E4. It can also be judged that it has shifted forward by “2.4”.

[Calculation method of length error value / phase error value]
Next, a method for calculating the length error value and the phase error value will be described with reference to FIG. 9, FIG. 10 (a), and FIG. 10 (b). Here, an example in which the length error value and the phase error value are calculated for each of the 57 recording patterns shown in FIG. 9 will be described. For example, in the recording pattern 4Ts3Tm2Ts, the length of the recording mark (the length of the mark section) is “3T”, and the length of the space located immediately before the recording mark (the length of the space section immediately before the mark section) is set. The recording pattern is “4T” and the length of the space located immediately after the storage mark (the length of the space section immediately after the mark section) is “2T”.

  The error value (length error value and phase error value) of the recording pattern is the reliability of each of the start edge pattern and the end edge pattern corresponding to the mark section, the immediately preceding space section, and the immediately following space section indicated in the recording pattern. Calculated based on the value. For example, the error value of the recording pattern 3Ts3Tm3Ts includes the reliability value of the start edge pattern 3Ts3Tm in which the length of each of the mark section and the immediately preceding space section is “3T”, and the length of each of the mark section and the immediately following space section is “ And the reliability value of the end edge pattern 3Tm3Ts which is 3T ″.

Here, if the reliability of the start edge pattern is “Pas-Pbs” and the reliability of the termination edge pattern is “Pae-Pbe”, the edge shift value E5 of the start edge position and the edge shift value E6 of the termination edge position are ,
E5 = | Pas−Pbs | −Pstd
E6 = | Pae-Pbe | -Pstd
It is expressed. Further, the length error value Dl and the phase error value Dp can be expressed as (Equation 10) and (Equation 11).

  The absolute value of the length error value Dl indicates the amount of deviation of the length of the recording mark formed on the optical disc with respect to the ideal recording mark, and the sign of the length error value Dl is formed on the optical disc with respect to the ideal recording mark. The direction of deviation of the recorded mark length (long or short) is shown. The absolute value of the phase error value Dp indicates the amount of phase shift of the recording mark formed on the optical disc with respect to the ideal recording mark, and the sign of the phase error value Dp is formed on the optical disc with respect to the ideal recording mark. The recording mark phase shift direction (whether it is shifted forward or backward) is shown.

  A method for calculating the length error value and the phase error value will be specifically described with reference to FIGS. 10 (a) and 10 (b). The case where the length of each of the recording mark and the space immediately before and after the recording mark is “3T” (corresponding to the recording pattern 3Ts3Tm3Ts) will be described as an example.

FIG. 10A shows that the phase (center position) of the recording mark MB1 formed on the optical disc matches the phase (center position) of the ideal recording mark MA1, and the length of the recording mark MB1 formed on the optical disc is the same. A case where the length does not coincide with the ideal length of the recording mark MA1 (a case where a length error occurs) is shown. Also, the sample values (y _k−3 , y _k−2 , y _k−1 , y _k ) of the reproduction signal corresponding to the start edge portion of the recording mark MB1 are (5.2, 5.2, 3.2, 2). 1.2), and sample values (y _k−3 , y _k−2 , y _k−1 , y _k ) of the reproduction signal corresponding to the end edge portion of the recording mark MB1 are (1.2, 3.2). , 5.2, 5.2). In this case, the edge shift value E5 is calculated as “2.4”, and the edge shift value E6 is calculated as “2.4”. The length error value Dl is calculated as “4.8”, and the phase error value Dp is calculated as “0.0”. Accordingly, referring to the length error value Dl and the phase error value Dp, the phase (center position) of the recording mark MB1 formed on the optical disc matches the ideal phase (center position) of the recording mark MA1. It can be determined that the length of the recording mark MB1 formed on the optical disc is shorter by “4.8” than the ideal length of the recording mark MA1.

FIG. 10B shows that the length of the recording mark MB1 formed on the optical disc matches the length of the ideal recording mark MA1, and the phase (center position) of the recording mark MB1 is the phase of the ideal recording mark MA1 ( (Center position) does not match (when a phase error occurs). Also, the sample values (y _k−3 , y _k−2 , y _k−1 , y _k ) of the reproduction signal corresponding to the start edge portion of the recording mark MB1 are (5.2, 5.2, 3.2, 2). 1.2), and sample values (y _k−3 , y _k−2 , y _k−1 , y _k ) of the reproduction signal corresponding to the end edge portion of the recording mark MB1 are (0.8, 2.8). , 4.8, 4.8). In this case, the edge shift value E7 is calculated as “2.4”, and the edge shift value E8 is calculated as “−2.4”. The length error value Dl is calculated as “0.0”, and the phase error value Dp is calculated as “4.8”. Therefore, with reference to the length error value Dl and the phase error value Dp, the length of the recording mark MB1 formed on the optical disc matches the ideal length of the recording mark MA1, but it is formed on the optical disc. It can be determined that the phase (center position) of the recording mark MB1 is shifted backward by "4.8" from the ideal phase (center position) of the recording mark MA1.

  As described above, when the sign of the length error value Dl is positive, it can be determined that the length of the recording mark MB1 formed on the optical disc is shorter than the ideal length of the recording mark MA1, and the length error When the sign of the value Dl is negative, it can be determined that the length of the recording mark MB1 formed on the optical disc is longer than the ideal length of the recording mark MA1. When the sign of the phase error value Dp is positive, the phase (center position) of the recording mark MB1 formed on the optical disc is shifted backward from the phase (center position) of the ideal recording mark MA1. When the sign of the phase error value Dp is negative, the phase (center position) of the recording mark MB1 formed on the optical disc is shifted forward from the phase (center position) of the ideal recording mark MA1. Can be judged.

  When the sign of the length error value Dl calculated by (Equation 10) is inverted and the sign of the length error value Dl is positive, the length of the recording mark MB1 formed on the optical disc is ideal. When it is determined that the length of the recording mark MA1 is longer than the length of the typical recording mark MA1, and the sign of the length error value D1 is negative, the length of the recording mark MB1 formed on the optical disc is larger than the length of the ideal recording mark MA1. May be judged to be short. Similarly, when the sign of the phase error value Dp calculated by (Equation 11) is inverted and the sign of the phase error value Dp is positive, the phase (center of the recording mark MB1 formed on the optical disk is determined. Position) is shifted forward from the phase (center position) of the ideal recording mark MA1, and when the sign of the phase error value Dp is negative, the phase of the recording mark MB1 formed on the optical disc It may be determined that (center position) is shifted backward from the phase (center position) of the ideal recording mark MA1.

  The correspondence between the sign of the edge shift value and the shift direction is the state transition sequence determined to be the most probable and the state transition sequence not determined to be the most probable (the state transition determined to be the second most probable Depending on the relationship between each expected value series in the column) and the sample value series of the reproduction signal. In consideration of such characteristics, the calculation formulas (Equation 10) and (Equation 11) for the length error value Dl and the phase error value Dp may be appropriately changed.

[Recording pulse]
Next, the recording power of the recording pulse and the shape of the recording pulse will be described with reference to FIG. Here, the shape of the recording pulse is determined by the top pulse start position, the top pulse width, the end pulse width, and the cooling end position.

  As for the power of the recording pulse, the peak power Pw, bias power Pb, and cooling power Pc used for forming the recording mark on the optical disc and the recording mark already formed on the optical disc are erased to form a space. And the erase power Pe used in the above. The peak power Pw, the bias power Pb, the cooling power Pc, and the erase power Pe are set based on the extinction level detected when the laser light is extinguished. The power levels of the peak power Pw, bias power Pb, cooling power Pc, and erase power Pe are constant regardless of the length of the recording mark to be formed on the optical disc (the length of the mark section of the recording code). It may be set as described above, or may be changed according to the length of the recording mark or the length of the space (the length of the mark section of the recording code or the length of the space section).

  Further, the top pulse start positions dTtop2T, dTtop3T, dTtop4T, dTtop5T and the top pulse widths Ttop2T, Ttop3T, Ttop4T, Ttop5T according to the length of the recording mark (2T, 3T, 4T, 5T or more) to be formed on the optical disc. And cooling end positions dTe2T, dTe3T, dTe4T, and dTe5T are set. The top pulse start positions dTtop2T,..., DTtop5T indicate the time interval between the rising edge position of the first pulse and the rising edge position of the channel clock, and the top pulse widths Ttop2T,. The cooling end positions dTe2T,..., DTe5T indicate the time interval between the end position of the cooling power Pc and the rising edge position of the channel clock.

  The number of multi-pulses (second and subsequent pulses) is set according to the length of the recording mark excluding “2T”. For example, when the length of the recording mark to be formed on the optical disc is “3T”, one multipulse is generated, and when the length of the recording mark is “5T”, four multipulses are generated. Is generated, and when the length of the recording mark is “6T”, five multi-pulses are generated. The pulse width Tmp of the multi-pulse may be set to be constant regardless of the length of the recording mark, or may be changed according to the length of the recording mark or the length of the space.

  Furthermore, end pulse widths Te3T, Te4T, and Te5T may be set according to the length of the recording mark excluding “2T” (3T, 4T, and 5T or more). End pulse widths Te3T, Te4T, and Te5T indicate the pulse width of the last multi-pulse.

  Note that the recording parameter indicating the correspondence between the length of the recording mark and the shape of the recording pulse (recording power, pulse width, pulse position, etc.) may be registered in the disc information stored in a predetermined area of the optical disc. good. Further, the initial shape of the recording pulse may be set based on the recording parameter registered in the disc information. Further, when the recording parameter is not registered in the disc information, the initial shape of the recording pulse may be set to a predetermined shape (for example, a shape where the top pulse start position and the cooling end position are “0”). .

[Record mark edge position adjustment]
By changing the top pulse start position dTtop2T and / or the top pulse width Ttop2T, the start edge position of the 2T mark (the recording mark whose length corresponds to “2T”) can be adjusted, the cooling end position dTe2T and / or the top pulse By changing the width Ttop2T, the end edge position of the 2T mark can be adjusted. Further, by changing the top pulse start positions dTtop3T, dTtop4T, dTtop5T and / or the top pulse widths Ttop3T, Ttop4T, Ttop5T, a 3T mark (a recording mark corresponding to a length “3T”), a 4T mark (a length) The start edge position of the recording mark corresponding to “4T” and 5T mark (the recording mark corresponding to “5T”) can be adjusted, and the cooling end position dTe3T, dTe4T, dTe5T and / or the end pulse width Te3T, Te4T. , Te5T can be changed to adjust the end edge position of the 3T mark, 4T mark, and 5T mark.

[Record mark length adjustment / phase adjustment]
Further, the length error and phase error of the recording mark can be adjusted by appropriately adjusting the starting edge position and the ending edge position of the recording mark.

  For example, the top pulse start positions dTop2T, dTtop3T, dTtop4T, dTtop5T and / or the top pulse widths Ttop2T, Ttop3T, Ttop4T, Ttop5T are increased, and the cooling end positions dTe2T, dTe3T, dTe4T, and dTe5T are recorded. The length can be increased, and the top pulse start positions dTop2T, dTtop3T, dTtop4T, dTtop5T and / or the top pulse widths Ttop2T, Ttop3T, Ttop4T, Ttop5T are reduced and the cooling end positions dTe2T, dTe3T, dTe5T, Te are increased. By doing so, the length of the recording mark can be shortened.

  Further, by increasing the top pulse start positions dTop2T, dTtop3T, dTtop4T, dTtop5T, and by increasing the cooling end positions dTe2T, dTe3T, dTe4T, dTe5T, the phase (center position) of the recording mark can be shifted forward. By reducing the top pulse start positions dTop2T, dTtop3T, dTtop4T, and dTtop5T and decreasing the cooling end positions dTe2T, dTe3T, dTe4T, and dTe5T, the phase of the recording mark can be shifted backward.

[Change in length error value]
Next, the correspondence between the adjustment amount of the recording pulse shape and the change amount of the length error value will be described with reference to FIGS. 12 (a) to 12 (e) and FIG. Here, a case where the length of the recording mark is “3T” will be described as an example.

  As shown in FIGS. 12A to 12E, the top pulse start position and the top pulse width are increased at a time interval Δt (a constant time interval), and the cooling end position is decreased at a time interval Δt. The length of the recording mark can be gradually increased. That is, the length of the recording mark formed by the recording pulse shown in FIG. 12A is the shortest, and the length of the recording mark formed by the recording pulse shown in FIG. Further, by increasing the length of the recording mark in the order of FIG. 12A to FIG. 12E, the length error value of the recording mark is represented by the symbols (a) to (e) shown in FIG. It gradually changes in the order of. Note that the length error values corresponding to the symbols (a) to (e) shown in FIG. 13 are the recording marks formed by the recording pulses shown in FIGS. 12 (a) to 12 (e), respectively. The length error value is shown. Here, when the length target value is “0”, the shape of the recording pulse shown in FIG. 12C is an optimum shape.

[Change in phase error value]
Next, with reference to FIG. 14A to FIG. 14E and FIG. 15, the correspondence between the adjustment amount of the recording pulse shape and the change amount of the phase error value will be described. Here, a case where the length of the recording mark is “3T” will be described as an example.

  As shown in FIGS. 14A to 14E, the top pulse start position and the top pulse width are increased at the time interval Δt, and the cooling end position is increased at the time interval Δt. (Center position) can be gradually shifted forward. That is, the phase of the recording mark formed by the recording pulse shown in FIG. 14A is the most backward, and the phase of the recording mark formed by the recording pulse shown in FIG. is there. By shifting the phase of the recording mark forward in the order of FIG. 14A to FIG. 14E, the phase error value of the recording mark is changed in the order of symbols (a) to (e) shown in FIG. Change gradually. The phase error values corresponding to the symbols (a) to (e) shown in FIG. 15 are the values of the recording marks formed by the recording pulses shown in FIGS. 14 (a) to 14 (e), respectively. The phase error value is shown. Here, when the phase target value is “0”, the shape of the recording pulse shown in FIG. 14C is an optimum shape.

  Of the 57 recording patterns, at least a difference value between a recording pattern (for example, an error value (length error value and / or phase error value) and a target value (length target value and / or phase target value) is the largest. For a large recording pattern), the error probability in the maximum likelihood decoding process can be reduced by adjusting the shape of the recording pulse corresponding to the recording pattern so that the error value of the recording pattern approaches the target value. Yes (that is, the recording quality can be improved). For example, when the difference value between the error value of the recording pattern 3Ts3Tm3Ts and the target value is the largest of the 57 recording patterns, the shape of the recording pulse corresponding to the 3T mark so that the error value of the recording pattern 3Ts3Tm3Ts approaches the target value (Top pulse start position dTtop3T, top pulse width Ttop3T, end pulse width Te3T, cooling end position dTe3T) may be adjusted.

  When both the start edge portion and the end edge portion of the recording mark are changed simultaneously, it is ideal that the amount of change in the edge position in each of the start edge portion and the end edge portion is the same. However, for example, when the amount of heat accumulated in accordance with the laser beam differs due to the difference in the medium constituting the optical disc or the structure of the optical disc, the amount of change in the edge position at each of the start edge portion and the end edge portion is not the same. There are cases. In this case, the phase of the recording mark will change unintentionally. Therefore, it is preferable to execute the phase adjustment of the recording mark after the length adjustment of the recording mark.

  Also, if the rising edge position of the multi-pulse cannot be adjusted when adjusting the phase of the recording mark, the time interval between the top pulse and the second multi-pulse or the end pulse is used for the recording mark having a length of “4T” or more. And the time interval between the multi-pulse immediately before the end pulse may not be constant. Therefore, the pulse width and position of the recording pulse may be changed as necessary. For example, the adjustment amount of the top pulse width may be made larger than the time interval Δt, and the adjustment amount of the cooling end position may be set to the time interval Δt / 2. When performing such adjustment, it is desirable to detect that the recording mark length has not changed by detecting the recording mark length error.

[Adjustment amount of recording pulse shape]
Although the case where the recording pulse shape adjustment amount (time interval Δt) is a fixed time interval has been described as an example, the recording pulse shape adjustment amount may not be a fixed time interval. For example, when the correspondence between the adjustment amount of the recording pulse shape and the length error value (or phase error value) is non-linear, the adjustment amount of the recording pulse shape is changed according to the correspondence relationship. May be.

[Edge position adjustment priority]
In the adjustment of the recording mark length error, both the starting edge position and the ending edge position may be changed simultaneously, or either the starting edge position or the ending edge position may be preferentially adjusted. . For example, when only the start edge position is adjusted (for example, when adjusting only the top pulse start position and the top pulse width) rather than when adjusting only the end edge position (for example, when adjusting only the cooling end position) When the shape change amount of the recording mark is larger, it is preferable to adjust the start edge position before the end edge position.

(optical disk)
FIG. 16 shows an example of the structure of the optical disc 10 shown in FIG. The optical disc 10 includes an inner circumference power calibration area (inner circumference PCA), a lead-in area, a data area, a lead-out area, and an outer circumference power calibration area (outer circumference PCA). The inner circumference PCA and the outer circumference PCA are areas used for a calibration operation (for example, optimization of recording power) by the optical disc recording / reproducing apparatus. The lead-in area and the lead-out area are areas for storing information related to the optical disc 10 and information for managing the recording state of the optical disc 10. The data area is an area for storing recording data (for example, user data). Here, in the lead-in area and the lead-out area, disk information, defect management information, and the like are stored. In the disc information, the disc type of the optical disc 10 and the optimum value of the recording parameter (the optimum value of the shape of the recording pulse) are registered. Has been.

(Recording / playback unit)
The recording / reproducing unit 11 includes a buffer 101, a recording compensation unit 102, a laser driving unit 103, and an optical head 104.

  The buffer 101 accumulates recording data WD (recording code) to be recorded on the optical disc 10, and outputs the recording data WD in a predetermined data block unit (for example, ECC block unit) in response to control by the controller 15. The recording compensation unit 102 converts the data block DB (predetermined amount of recording data WD) from the buffer 101 into a recording pulse WP based on the recording parameters set by the controller 15. As shown in FIG. 17, the recording parameters include the length of the mark section of the recording data WD (the length of the recording mark to be formed on the optical disc 10) and the shape of the recording pulse (here, the top pulse start position, the top pulse). (Width, end pulse width, cooling end position). For example, the top mark start position dTtop3T, the top pulse width Ttop3T, the end pulse width Te3T, and the cooling end position dTe3T are associated with the recording mark length “3T”.

  The laser drive unit 103 controls the light emission operation of the recording laser of the optical head 104 based on the recording pulse WP obtained by the recording compensation unit 102. The laser drive unit 103 controls the light emission operation of the reproduction laser of the optical head 104 in response to the control by the controller 15. The optical head 104 can switch between the recording mode and the reproduction mode in response to control by the controller 15. When the recording mode is set, the optical head 104 irradiates the recording area with the recording beam in response to the control by the laser driving unit 103. As a result, a recording area composed of a plurality of recording marks and spaces is formed in the data area of the optical disc 10. When the reproduction mode is set, the optical head 104 irradiates the recording area formed in the data area of the optical disc 10 with a reproduction beam in response to the control by the laser driving unit 103. As a result, the analog reproduction signal AS is generated. For example, the optical head 104 includes a light source that irradiates the optical disc 10 with a recording beam and a reproduction beam, a light receiving unit that receives reflected light from the optical disc 10 and generates an analog reproduction signal AS according to the light intensity of the reflected light, A focus control unit that adjusts the focal position of the recording beam and the reproduction beam and a tracking control unit that adjusts the tracking position of the optical disc 10 may be included.

(Reproduction processing part)
The reproduction processing unit 12 includes a preamplifier 201, an automatic gain controller (AGC) 202, a waveform equalizer 203, a clock generator 204, and an analog / digital converter (ADC) 205.

  The preamplifier 201 amplifies the analog reproduction signal AS generated by the recording / reproducing unit 11. The automatic gain controller 202 amplifies or attenuates the analog reproduction signal from the preamplifier 201. The automatic gain controller 202 adjusts its amplification gain so that the output of the waveform equalizer 203 has a constant amplitude. The waveform equalizer 203 shapes the analog reproduction signal from the automatic gain controller 202 and outputs it as an analog reproduction signal Asa. The clock generator 204 generates a reproduction clock CLK based on the analog reproduction signal Asa. In addition, the clock generator 204 detects the phase error value PD between the analog reproduction signal Asa and the reproduction clock CLK, and adjusts the frequency of the reproduction clock CLK so that the phase error value PD becomes small. The analog / digital converter 205 converts the analog reproduction signal Asa into the digital reproduction signal DS in synchronization with the reproduction clock CLK. Note that the reproduction processing unit 12 may include a digital filter that executes waveform equalization processing in the subsequent stage of the analog / digital converter 205 instead of the waveform equalizer 203.

(Decryption processing unit)
The decoding processing unit 13 includes a shaping unit 301 and a maximum likelihood decoding unit 302. The shaping unit 301 uses the digital reproduction signal so that the frequency characteristic of the digital reproduction signal DS becomes equal to the characteristic assumed in the maximum likelihood decoding unit 302 (for example, PR (1, 2, 2, 1) equalization characteristic). The digital reproduction signal D301 is generated by adjusting the frequency of the DS. For example, the shaping unit 301 may be configured with a digital filter. When the reproduction distortion of the digital reproduction signal DS is small (when the frequency characteristic of the digital reproduction signal DS can be regarded as an equalization characteristic assumed in the maximum likelihood decoding process), the decoding processing unit 13 includes the shaping unit 301. May not be included.

  The maximum likelihood decoding unit 302 performs the maximum likelihood decoding process on the digital reproduction signal D301 generated by the shaping unit 301 to generate the most likely binary signal D302. More specifically, the maximum likelihood decoding unit 302 has a plurality of transitions from the first state at time k−n (n is an integer equal to or greater than 1 and here n = 4) to the second state at time k. The most probable state transition sequence (the state transition sequence having the smallest difference square sum between the expected value sequence and the sample value sequence of the digital reproduction signal D301) is selected from the state transition sequences of The binarized signal D302 is output. For example, the maximum likelihood decoding unit 302 may be configured by a Viterbi decoding circuit.

(Recording and playback processing)
As shown in FIG. 18, the recording data WD is converted into the recording pulse WP by the recording operation of the recording / reproducing unit 11, and a recording mark is formed in the data area of the optical disc 10 based on the recording pulse WP. Further, the reproduction operation by the recording / reproducing unit 11 generates an analog reproduction signal AS based on the recording mark, and the reproduction processing unit 12 converts the analog reproduction signal AS into a digital reproduction signal DS. Then, the decoding processing unit 13 generates a binarized signal D302 based on the digital reproduction signal DS (or the digital reproduction signal D301 waveform-shaped by the shaping unit 301).

(Quality information detector)
The quality information detection unit 14 includes a reliability calculation unit 401, an edge pattern detection unit 402, a reliability storage unit 403, and a transfer unit 404.

[Reliability Calculator]
The reliability calculation unit 401 detects state transitions from time k-4 to time k based on the bit values of the binarized signal D302 at time k-6 to time k, and state transition sequences P1A, P1B,. , P8A, and P8B, the state transition sequence (first state transition sequence) determined to be the most probable by the maximum likelihood decoding unit 302 and the state transition sequence selected as the second most probable (the second state sequence) State transition sequence) is detected. Then, the reliability calculation unit 401 calculates the first index value indicating the probability of the first state transition sequence (the square of the difference between the expected value sequence of the first state transition sequence and the sample value sequence of the digital reproduction signal D301). And a second index value indicating the probability of the second state transition sequence (sum of squared differences between the expected value sequence of the second state transition sequence and the sample value sequence of the digital reproduction signal D301) And a difference value between the first and second index values is calculated to calculate a reliability value indicating the reliability of the first state transition sequence. For example, the reliability calculation unit 401 may be configured by a differential metric detection circuit, or may be realized by a part of functions (a function for calculating the reliability value) of the maximum likelihood decoding unit 302.

As shown in FIG. 19, when the bit value of the binarized signal changes as “0, 0, 1, x, 0, 0, 0”, the reliability calculation unit 401 indicates that the state transition is “S2 _k−4 → S0 _k ”is detected. The state transition sequence determined to be the most probable is the state transition sequence P1A (path A of the pattern PP1), and the state transition sequence determined to be the second most probable is the state transition sequence P1B (path B of the pattern PP1). ), The reliability calculation unit 401 calculates a reliability value (Pa−Pb) from the index value Pa of the state transition sequence P1A and the index value Pb of the state transition sequence P1B, and the reliability value (Pa−Pb). ) As the reliability value DP1A of the state transition sequence P1A. In FIG. 19, reliability values DP1A, DP1B,..., DP8A, DP8B indicate the reliability values of the state transition sequences P1A, P1B,..., P8A, P8B, respectively. Thus, a reliability value is calculated for each state transition sequence.

[Edge pattern detector]
The edge pattern detection unit 402 detects an edge pattern for each transition edge of the binarized signal D302. More specifically, the edge pattern detection unit 402 detects a transition edge of the binarized signal D302, and responds to the transition edge based on two data intervals (intervals of 0 or 1) sandwiching the transition edge. Detect edge patterns. For example, in the edge pattern detection unit 402, the data section located immediately before the transition edge is a 2T space section (a space section having a length of “2T”), and the data section located immediately after the transition edge is a 3T mark section ( In the case of a mark section having a length of “3T”, it is determined that the edge pattern corresponding to the transition edge is the start edge pattern 2Ts3Tm. In this way, the edge pattern detection unit 402, for each transition edge of the binarized signal D302, has 15 start edge patterns and 15 end edges corresponding to the transition edge shown in FIG. It is determined which of the patterns is applicable.

(Reliability storage)
The reliability storage unit 403 stores the edge pattern detected by the edge pattern detection unit 402 in association with the reliability value calculated by the reliability calculation unit 401.

  As shown in FIG. 21, when the bit value of the binarized signal D302 changes to “1, 0, 0, 1, 1, 1, 0”, the reliability calculation unit 401 indicates that the state transition is “S5 → S1 → It is detected that S2 → S3 → S4 ″, and the reliability value DP6B of the state transition sequence P6B is calculated. On the other hand, since the bit value of the binarized signal D302 is changed to “1, 0, 0, 1, 1, 1, 0”, the edge pattern detection unit 402 detects the end edge pattern 2Tm3Ts. The reliability storage unit 403 stores the termination edge pattern 2Tm3Ts in association with the reliability value DP6B.

  When the bit value of the binarized signal D302 changes to “0, 1, 1, 1, 0, 0, 0, 1”, the reliability calculation unit 401 determines that the bit value “0, 1, 1, 1”. , 0, 0, 0 ”, the state transition“ S 2 → S 3 → S 4 → S 5 → S 0 ”is detected and the reliability value DP 1 B is calculated, and the bit values“ 1, 1, 1, 0, 0, 0, Based on “1”, the state transition “S3 → S4 → S5 → S0 → S1” is detected and the reliability value DP4A is calculated. On the other hand, since the bit value of the binarized signal D302 has changed to “0, 1, 1, 1, 0, 0, 0, 1”, the edge pattern detection unit 402 detects the start edge pattern 3Ts3Tm. The reliability storage unit 403 stores the start edge pattern 3Ts3Tm in association with the reliability values DP1B and DP4A.

  In this way, as shown in FIG. 22, the reliability values DP1A, DP1B,..., DP8A, DP8B calculated by the reliability calculation unit 401 are 15 start edge patterns and 15 end edge patterns, respectively. The data is stored in the reliability storage unit 403 in association with any one of them.

  Note that a buffer may be provided in each of the reliability calculation unit 401 and the edge pattern detection unit 402 in order to adjust the calculation timing of the reliability value and the detection timing of the edge pattern.

[Transfer section]
In response to the transfer instruction from the controller 15 (parameter control unit 503), the transfer unit 404 sends the reliability value (reliability value detected for each edge pattern) stored in the reliability storage unit 403 to the controller 15. Forward.

(Control part)
The controller 15 includes a mode control unit 501, a recording / reproduction control unit 502, and a parameter control unit 503. The mode control unit 501 sets the operation mode of the recording / playback control unit 502 and the parameter control unit 503 to either the write mode or the verify mode. Further, the mode control unit 501 sets the recording / reproduction control unit 502 and the parameter control unit 503 when the write period (for example, a period required for the recording process of the data block DB) has elapsed after setting the recording / reproduction control unit 502 and the parameter control unit 503 to the write mode. After the parameter control unit 503 is set to the verify mode and the recording / playback control unit 502 and the parameter control unit 503 are set to the verify mode, a verification period (for example, data block DB playback processing, reliability value detection processing, and recording parameter control) is set. When the period required for processing elapses, the recording / playback control unit 502 and the parameter control unit 503 are set to the write mode. The recording / playback control unit 502 sets the recording parameters of the recording / playback unit 11 and controls the recording process of the data block DB by the recording / playback unit 11 when the write mode is set. The recording / playback control unit 502 controls the playback process of the data block DB by the recording / playback unit 11 when the verify mode is set. When the verify mode is set, the parameter control unit 503 executes a recording parameter control process (error value calculation, quality improvement determination, quality defect determination, recording parameter adjustment, etc.).

(Information storage)
The information storage unit 16 stores recording setting information D601, quality management information D602, target setting information D603, and learning result information D604. For example, the information storage unit 16 may be configured by a rewritable memory.

[Record setting information]
As shown in FIG. 23, a plurality of recording parameters associated with different recording conditions (here, disc type, recording speed, recording position) are registered in the recording setting information D601. The disc type indicates information about the optical disc such as the name of the optical disc manufacturer, the type of the optical disc (DVD-RAM, BD-RE, etc.), the recording capacity of the optical disc, and the recording layer in the multilayer disc. The recording speed indicates information relating to the recording speed such as the optical disc rotation method (CAV, CLV, etc.) and the rotation speed (double speed, triple speed, etc.). The recording position indicates the position of one of the divided areas Z1, Z2,..., Zn obtained by dividing the data area of the optical disc. Here, the recording parameters are managed hierarchically. .., Discn (n is an integer of 2 or more) is associated with recording speeds CAV1, CAV2,..., CAVn, CLV1, CLV2,. , CAV2, ..., CAVn, CLV1, CLV2, ..., CLVn are associated with recording positions Z1, Z2, ..., Zn, and recording parameters Z1, Z2, ..., Zn have recording parameters. It is associated.

[Quality control information]
As shown in FIG. 24, a plurality of pieces of reliability information associated with different recording conditions (here, disc type, recording speed, recording position) are registered in the quality management information D602. In the reliability information, a reliability value detected for each edge pattern is registered. Here, the reliability information is managed hierarchically.

[Target setting information]
As shown in FIG. 25, a plurality of pieces of target information associated with different recording conditions (here, disc type, recording speed, and recording position) are registered in the target setting information D603. In the target information, a length target value and a phase target value set for each recording pattern are registered. Here, the length target values DLT323, DLT423,..., DLT555 indicate the length target values set for the 57 recording patterns 3Ts2Tm3Ts, 4Ts2Tm3Ts,. .., DPT555 indicate phase target values set for 57 recording patterns 3Ts2Tm3Ts, 4Ts2Tm3Ts,..., 5Ts5Tm5Ts, respectively.

[Learning result information]
The learning result information D604 is information indicating the learning result of the recording parameter by the write and verify operation of the optical disc recording / reproducing apparatus, and has the same structure as the recording setting information D601.

(Write and verify operation)
Next, with reference to FIG. 26, a write and verify operation by the optical disc recording / reproducing apparatus shown in FIG. 1 will be described.

<Step ST101>
First, the optical disk 10 is loaded in the optical disk recording / reproducing apparatus, and in order to start the write and verify operation, the recording / reproducing control unit 502 and the parameter control unit 503 perform recording conditions (here, the optical disk type, the recording speed) by external control. , Recording position) is set. The mode control unit 501 sets the recording / playback control unit 502 and the parameter control unit 503 to the write mode. The recording / playback control unit 502 selects the first data block DB stored in the buffer 101 as a target for the recording process. Further, the recording / playback control unit 502 controls the recording / playback unit 11 to play back the disc information stored in the lead-in area or the lead-out area of the optical disc 10. As a result, the disc information is read as the binarized signal D302 via the reproduction processing unit 12 and the decoding processing unit 13. Note that the recording / playback control unit 502 and the parameter control unit 503 may detect information related to the optical disc type from the disc information.

<Step ST102>
Next, the recording / playback control unit 502 determines whether or not a recording parameter corresponding to the current recording condition is registered in the learning result information D604 stored in the information storage unit 16. If a recording parameter corresponding to the current recording condition is registered, the process proceeds to step ST103, and if not, the process proceeds to step ST104.

<Step ST103>
The recording / playback control unit 502 reads a recording parameter (recording parameter corresponding to the current recording condition) registered in the learning result information D604, and sets the read recording parameter as a recording parameter of the recording compensation unit 102. Further, the recording / playback control unit 502 registers the recording parameters read from the learning result information D604 in the recording setting information D601 in association with the current recording conditions. Next, the process proceeds to step ST105.

<Step ST104>
On the other hand, when the recording parameter corresponding to the current recording condition is not registered in the learning result information D604, the recording / reproducing control unit 502 records the recording parameter indicated in the disc information read from the optical disc 10 by the recording / reproducing unit 11. Set as a recording parameter. In addition, the recording / playback control unit 502 registers the recording parameters shown in the disc information in the recording setting information D601 in association with the current recording conditions. Next, the process proceeds to step ST105.

<Step ST105>
Next, the recording / reproducing control unit 502 is based on the current recording condition so that the i-th data block (the data block selected as the target of the recording process) is recorded at a predetermined position in the data area of the optical disc 10. The buffer 101, the recording compensation unit 102, the laser driving unit 103, and the optical head 104 are controlled. The buffer 101 outputs the i-th data block DB, and the recording compensation unit 102 converts the i-th data block DB into a recording pulse WP based on the recording parameters set by the recording / playback control unit 502, The laser driver 103 controls the recording laser emission operation by the optical head 104 based on the recording pulse WP. In this way, the i-th recording area corresponding to the i-th data block is formed at a predetermined position in the data area of the optical disc 10.

<Step ST106>
Next, when the write period elapses after the recording / playback control unit 502 and parameter control unit 503 are set to the write mode, the mode control unit 501 sets the recording / playback control unit 502 and parameter control unit 503 to the verify mode. The recording / reproducing control unit 502 controls the laser driving unit 103 and the optical head 104 based on the current recording conditions so that the i-th data block recorded at a predetermined position in the data area of the optical disc 10 is reproduced. . The laser drive unit 103 controls the light emission operation of the reproduction beam by the optical head 104, and the optical head 104 irradiates the i-th recording area formed at a predetermined position in the data area of the optical disc 10 with the reproduction beam. An analog reproduction signal AS is generated based on the reflected light. The reproduction processing unit 12 converts the analog reproduction signal AS into a digital reproduction signal DS, and the decoding processing unit 13 performs a maximum likelihood decoding process on the digital signal DS to generate a binary signal D302.

<Step ST107>
The quality information detection unit 14 detects an edge pattern for each transition edge of the binarized signal D302 obtained by the decoding processing unit 13, and detects a reliability value for each edge pattern.

<Step ST108>
The parameter control unit 503 instructs the quality information detection unit 14 to transfer the reliability value detected for each edge pattern, and the reliability information registered in the quality management information D602 stored in the information storage unit 16 Among them, the reliability value transferred from the quality information detection unit 14 is registered in the reliability information corresponding to the current recording condition. Next, the parameter control unit 503 determines an error value (length) for each recording pattern based on the reliability value (reliability value detected for each edge pattern) registered in the reliability information corresponding to the current recording condition. Error error value and / or phase error value). In addition, the parameter control unit 503 performs quality improvement determination (processing for determining whether or not recording parameter adjustment is necessary) and quality failure determination (whether the data block is poor quality) based on the error value calculated for each recording pattern. In accordance with the result of the quality improvement determination, the recording parameter corresponding to the current recording condition among the recording parameters registered in the recording setting information D601 stored in the information storage unit 16 is indicated. The shape of the recorded pulse (here, top pulse start position, top pulse width, end pulse width, cooling end position) is adjusted.

<Step ST109>
Next, when the verify period elapses after the recording / playback control unit 502 and parameter control unit 503 are set to the verify mode, the mode control unit 501 determines whether or not to end the write and verify operation. When the write and verify operation is continued (for example, when recording of the recording data WD is not completed), the process proceeds to step ST110, and when the write and verify operation is terminated (for example, recording data WD If the recording is completed), the process proceeds to step ST113.

<Step ST110>
The recording / reproducing control unit 502 confirms whether or not the parameter control unit 503 determines in step ST108 that the i-th data block is poor in quality. If the i-th data block is not defective, the process proceeds to step ST111, and if the i-th data block is defective, the process proceeds to step ST114.

<Step ST111>
Next, the mode control unit 501 sets the recording / playback control unit 502 and the parameter control unit 503 to the write mode. The recording / playback control unit 502 selects the (i + 1) th data block (next data block) as a target for recording processing.

<Step ST112>
Next, the recording / playback control unit 502 determines whether or not the recording condition has been changed. If the recording condition is changed, the process proceeds to step ST102. On the other hand, when the recording condition is not changed, the recording / reproducing control unit 502 sets the recording parameter adjusted in step ST108 as the recording parameter of the recording / reproducing unit 11. Next, the process proceeds to step ST105.

<Step ST113>
On the other hand, when it is determined in step ST109 that the write and verify operation is to be terminated, the parameter control unit 503 selects a recording parameter adjusted by the write and verify operation from among the recording parameters registered in the recording setting information D601. The learning result information D604 is overwritten. For example, when the recording parameters corresponding to the disc type Disc1, recording speed CAV1, and recording position Z1 are adjusted, the parameter control unit 503 causes the disc type Disc1, recording speed CAV1, and recording position registered in the learning result information D604. The recording parameter corresponding to Z1 is rewritten to the recording parameter corresponding to the disc type Disc1, recording speed CAV1, and recording position Z1 registered in the recording setting information D601. In this way, the recording parameter registered in the learning result information D604 is updated.

<Step ST114>
When it is confirmed in step ST110 that the i-th data block is of poor quality, the recording / playback control unit 502 sets the recording parameter adjusted in step ST108 as the recording parameter of the recording / playback unit 11. Next, the recording / playback control unit 502 selects the i-th data block again as a target of the recording process, and the i-th data block is located in the alternate sector of the optical disc 10 (immediately after the i-th recording area). The recording / reproducing unit 11 is controlled so as to be re-recorded in an area or an area prepared in advance as a replacement sector in the optical disc 10. Further, the recording / reproducing control unit 502 stores defect management information (for example, the address of the replacement sector) indicating that the i-th data block has been recorded in the replacement sector in the lead-in area of the optical disc 10. The recording / reproducing unit 11 is controlled. Next, the process proceeds to step ST106.

(Recording parameter control processing)
Next, recording parameter control processing (step ST108) by the optical disc recording / reproducing apparatus shown in FIG. 1 will be described with reference to FIG.

<Step ST201>
The parameter control unit 503 transfers the reliability value of the edge pattern to be used for adjusting the recording parameter among the reliability values detected for each edge pattern (reliability values stored in the reliability storage unit 403). Instruct the quality information detection unit 14 (transfer unit 404). The quality information detection unit 14 transfers the reliability value to the controller 15 in response to an instruction from the controller 15. The parameter control unit 503 registers the reliability value transferred from the quality information detection unit 14 in the quality management information D602. For example, the parameter control unit 503 transfers the reliability value of the edge pattern corresponding to the 2T mark in the first verification period in order to adjust the shape of the recording pulse corresponding to the 2T mark in the first verification period. In order to adjust the shape of the recording pulse corresponding to the 3T mark in the second verification period, the reliability value of the edge pattern corresponding to the 3T mark is transferred in the second verification period. May be instructed.

<Step ST202>
Next, the parameter control unit 503 calculates an error value (length error value and / or phase error value) for each recording pattern based on the reliability value registered in the quality management information D602. For example, in the first verification period, the parameter control unit 503 calculates an error value of the recording pattern corresponding to the 2T mark based on the reliability value of the edge pattern corresponding to the 2T mark, and the second verification period. Then, the error value of the recording pattern corresponding to the 3T mark may be calculated based on the reliability value of the edge pattern corresponding to the 3T mark.

<Step ST203>
Next, the parameter control unit 503 selects any one recording pattern as a determination target from among the recording patterns for which quality determination (quality improvement determination and quality defect determination) has not yet been performed. For example, the parameter control unit 503 selects a recording pattern for which quality determination has not yet been performed among the recording patterns corresponding to the 2T mark in the first verification period, and sets the 3T mark in the second verification period. You may select the recording pattern from which the quality determination is not yet performed among the corresponding recording patterns.

<Step ST204: Quality Improvement Determination>
Next, the parameter control unit 503 selects target information corresponding to the current recording condition from the target information registered in the target setting information D603, and sets the target value (length target value) registered in the selected target information. And / or a phase error value), a target value corresponding to the recording pattern to be determined is selected. The parameter control unit 503 calculates a difference value between the error value of the determination target recording pattern and the target value, and an improvement reference value in which the difference value between the error value of the determination target recording pattern and the target value is set in advance. It is judged whether it is larger than. The improvement reference value is a reference value for determining whether or not it is necessary to adjust the shape of the recording pulse indicated by the recording parameter. If the difference value between the error value and the target value is larger than the improvement reference value, the process proceeds to step ST205, and if not, the process proceeds to step ST208.

<Step ST205>
Next, the parameter control unit 503 determines that the recording pattern to be determined is “necessity of improvement (recording pattern to be used for adjusting recording parameters)”.

<Step ST206: Quality Defect Determination>
Next, the parameter control unit 503 determines whether or not the difference value between the error value of the recording pattern to be determined and the target value is greater than a preset defect reference value. The defect reference value is a reference value for determining whether or not the i-th data block is defective in quality (whether re-recording in a replacement sector is necessary), and is larger than the improvement reference value. Value. If the difference value between the error value and the target value is larger than the defect reference value, the process proceeds to step ST207, and if not, the process proceeds to step ST208.

<Step ST207>
Next, the parameter control unit 503 determines that the i-th data block is “quality defect (data block that needs to be re-recorded in a replacement sector)”.

<Step ST208>
Next, the parameter control unit 503 determines whether or not to end the quality determination (quality improvement determination and quality defect determination). That is, the parameter control unit 503 determines whether or not the quality determination has been completed for the recording pattern to be used for adjusting the recording parameter. For example, the parameter control unit 503 determines whether or not the quality determination has been completed for all the recording parameters corresponding to the 2T mark in the first verification period, and corresponds to the 3T mark in the second verification period. It may be determined whether or not the quality determination has been completed for all the recording parameters to be performed. When the quality determination ends, the process proceeds to step ST209. On the other hand, when continuing quality determination, it progresses to step ST203.

<Step ST209>
Next, the parameter control unit 503 sets the recording so that the error value of at least one recording pattern among the error values of the recording pattern determined to be improved approaches the target value (target value corresponding to the recording pattern). Of the recording parameters registered in the information D601, the shape of the recording pulse indicated by the recording parameter corresponding to the current recording condition is adjusted. For example, in the first verification period, the parameter control unit 503 sets the shape of the recording pulse corresponding to the 2T mark (top) so that the error value of the recording pattern corresponding to the 2T mark determined to be improved approaches the target value. The pulse start position dTtop2T, the top pulse width Ttop2T, and the cooling end position dTe2T) are adjusted so that the error value of the recording pattern corresponding to the 3T mark determined to be improved approaches the target value in the second verification period. The shape of the recording pulse corresponding to the 3T mark (top pulse start position dTtop3T, top pulse width Ttop3T, end pulse width Te3T, cooling end position dTe2T) may be adjusted.

(Start-up time)
Next, with reference to FIG. 28A and FIG. 28B, the activation time (time until recording of recording data to be recorded on the optical disk is started) will be described.

  As shown in FIG. 28 (a), the conventional apparatus (for example, Patent Documents 1, 2, and 3) performs servo learning processing (optimization of tracking control, optimization of focus control) in the inner peripheral power calibration region of the optical disc. After performing the recording learning process (optimization of recording power, optimization of the shape of the recording pulse), the recording process is executed in the data area of the optical disc. In this case, the start-up time corresponds to the time required for servo learning processing, recording power optimization, and recording pulse shape optimization.

  On the other hand, as shown in FIG. 28 (b), the optical disc recording / reproducing apparatus shown in FIG. 1 executes the servo learning process and the recording learning process (optimization of recording power) in the inner peripheral power calibration area of the optical disc, The write and verify operation is executed in the data area. In this case, the startup time corresponds to the time required for servo learning processing and recording power optimization. As described above, in the optical disk recording / reproducing apparatus shown in FIG. 1, the time spent for adjusting the recording parameters (record pulse shape) is not concentrated at the start of the activation of the optical disk recording / reproducing apparatus. Can be shortened.

(Recording quality)
Next, recording quality (error probability in the maximum likelihood decoding process) will be described with reference to FIG. Here, a case where the rotation speed of the optical disk is controlled to be constant will be described as an example.

  When the optimum value of the shape of the recording pulse at each position in the data area is linearly predicted based on the optimum value of the shape of the recording pulse in the inner circumference power calibration area (in the case of inner circumference PCA learning), a recording mark is to be formed. As the position is farther from the inner peripheral power calibration area, the amount of difference in the recording mark formation conditions (for example, linear velocity, physical characteristics, etc.) increases, and the recording quality deteriorates. In particular, as the distance from the central portion in the radial direction of the optical disk increases (the closer to the inner or outer periphery of the optical disk), the variation in the physical characteristics of the optical disk (for example, heat transfer coefficient) increases. Even if the shape of the recording pulse is optimized, the recording quality deteriorates significantly in the outer peripheral portion of the optical disk. Even when the rotational speed of the optical disc is controlled so that the linear velocity of the optical disc is constant, there is a possibility that the recording quality may be deteriorated due to variations in physical characteristics of the optical disc.

  When linearly predicting the optimum value of the recording pulse shape at each position in the data area based on the optimum value of the recording pulse shape in each of the inner power calibration area and the outer power calibration area (in the case of inner / outer PCA learning) ) In the vicinity of the inner power calibration area, in the vicinity of the outer power calibration area, and in the central area of the data area in the radial direction of the optical disc, the recording quality is relatively less deteriorated. Degradation of quality becomes remarkable. Even when the rotational speed of the optical disc is controlled so that the linear velocity of the optical disc is constant, there is a possibility that the recording quality may be deteriorated due to variations in the physical characteristics of the optical disc.

  On the other hand, in the optical disc recording / reproducing apparatus shown in FIG. 1 (in the case of write and verify), a write process for recording a predetermined amount of recording data, and the recording quality (reliability) of the predetermined amount of recording data recorded on the optical disc. The shape of the recording pulse can be gradually optimized by alternately repeating the verifying process for adjusting the shape of the recording pulse indicated by the recording parameter based on the value). In addition, since the position where the recording mark is to be formed by the recording process is adjacent to the position where the shape of the recording pulse has been adjusted by the verify process, the conditions for forming the recording mark are almost the same. Therefore, there is almost no deterioration in recording quality due to the difference in the recording mark formation conditions. Therefore, the optical disk recording / reproducing apparatus shown in FIG. 1 can improve the recording quality as compared with the conventional art. Even when the rotational speed of the optical disc is controlled so that the linear velocity of the optical disc is constant, the recording quality can be improved as compared with the conventional case.

  As described above, the start-up time can be shortened and the recording quality can be improved by adjusting the shape of the recording pulse indicated by the recording parameter by the write and verify operation. In general, “verify processing” refers to verifying the recording quality of a predetermined amount of recording data recorded on an optical disc. In this embodiment, “verify processing” refers to optical discs. Is to detect the recording quality of a predetermined amount of recording data recorded on the recording medium, and to adjust the shape of the recording pulse indicated by the recording parameter based on the recording quality.

[Record setting information]
Also, by recording the recording parameters in association with the recording conditions and registering them in the recording setting information D601, the recording parameters processed in the write-and-verify operation can be managed for each recording condition. As a result, even if the recording conditions are changed during the write and verify operation, the recording parameters optimized under the recording conditions before the change can be saved. The recording parameters can be optimized. Note that the recording parameters need not be managed for each recording condition.

[Learning result information]
Further, by managing the learning result of the recording parameter by the write and verify operation as the learning result information D604, it is possible to accumulate the learning result of the recording parameter. Thus, by continuing accumulation of learning results, the optimality of recording parameters can be improved. Further, by managing the recording parameters for each recording condition in the learning result information D604, it is possible to improve the optimality of the recording parameters for each recording condition. Note that the recording parameter learning result may not be managed for each recording condition.

[Quality control information]
Further, the reliability information indicating the reliability value detected for each edge pattern is associated with the recording condition and registered in the quality management information D602, so that the reliability detected for each edge pattern in the write and verify operation is recorded. The sex value can be managed for each recording condition. Thereby, even if the recording condition is changed during the write and verify operation, the reliability value detected under the recording condition before the change can be stored. Note that the reliability information may not be managed for each recording condition. Similarly to the recording setting information D601, the quality management information D602 may be stored in the information storage unit 16 as learning result information.

[Target setting information]
Furthermore, by registering the target information indicating the length target value and the phase target value set for each recording pattern in the target setting information D603 in association with the recording conditions, the length target value and the phase target for each recording condition are registered. The value can be managed. As a result, the length target value and the phase target value can be accurately set for each recording condition, so that the optimality of the recording parameters can be further improved. For example, by setting a target value for each optical disc type, it is possible to appropriately set the target value according to individual differences of optical discs (differences in optical disc materials, lot variations in optical disc manufacturing processes, etc.). Further, by setting a target value for each recording speed, it is possible to appropriately set the target value in consideration of the influence of thermal interference and thermal degeneration according to the recording speed. Further, by setting a target value for each recording position, the target value can be appropriately set according to the difference in physical characteristics at each position of the optical disc. Note that the length target value and the phase target value may not be managed for each recording condition.

  The target setting information D603 may be stored in the information storage unit 16 at the time of manufacturing the optical disc recording / reproducing apparatus, or may be updated after the manufacture of the optical disc recording / reproducing apparatus. For example, a target value corresponding to a new optical disc may be added to the target setting information D603 in association with the disc type of the optical disc.

  Further, the phase error value and the target error value may be values other than “0”. For example, another recording in which the thermal interference characteristics differ depending on the combination of the recording mark and the space, and the recording mark corresponding to a specific recording pattern (for example, the 5T mark corresponding to the recording pattern 2Ts5Tm2Ts) is positioned before and after the recording pattern. When the mark length or phase is affected, the phase target value of the recording pattern corresponding to other recording marks positioned before and after the specific recording pattern is set to “0” so that such influence is suppressed. A value other than may be set.

(Quality improvement judgment)
Further, by adjusting the recording parameters so that the error value of at least one recording pattern out of the recording patterns determined that the difference value between the error value and the target value is larger than the improvement reference value, the error is obtained. The recording quality can be improved so that the value becomes smaller than the improvement reference value.

(Quality defect judgment)
In addition, when a recording pattern in which the difference value between the error value and the target value is determined to be larger than the defect reference value is detected, the i-th recorded on the optical disc 10 by the previous recording operation by the recording / reproducing unit 11 is detected. By re-recording the data block DB in the alternate sector of the optical disc 10 by the next recording operation by the recording / reproducing unit 11, recorded data that cannot be normally reproduced due to poor quality can be relieved.

[Transfer processing]
Further, by transferring the reliability value to be used for adjusting the recording parameter among the reliability values detected for each edge pattern (reliability values stored in the reliability storage unit 403) for each verification period. The data bus between the quality information detection unit 14 (transfer unit 404) and the controller 15 (parameter control unit 503) is compared to the case where all reliability values detected for each edge pattern are transferred in one verification period. The amount of use can be reduced, and the time required for the transfer process between the quality information detector 14 and the controller 15 can be shortened. As a result, the adjustment of the recording parameters can be completed within the verify period.

  The parameter control unit 503 transfers the reliability values detected for each edge pattern in a predetermined order (for example, 2T mark, 3T mark,..., 5T mark) for each verification period. The transfer may be instructed so that all the reliability values detected for each edge pattern are transferred in one verify period. Further, the parameter control unit 503 causes the quality information detection unit 14 to transfer any of the reliability values detected for each edge pattern during the current verification period based on the calculation result of the error value in the previous recording parameter control process. You may decide.

(Jitter optimization)
When the jitter optimization is performed together with the optimization of the error probability of the maximum likelihood decoding process, the length target value and the phase error value may be changed according to the result of the jitter optimization. In this case, the length target value may be a value other than “0”.

[Jitter detection method]
Here, the jitter detection method will be described with reference to FIGS. 30 (a) to 30 (e). As shown in FIG. 30A, when a reproducing beam is irradiated onto a recording area composed of 2T space, 3T mark, 4T space, 2T mark, and 3T space, a reproducing waveform as shown by a solid line in FIG. Is generated. Here, when the analog reproduction signal is binarized based on a predetermined threshold voltage (broken line in FIG. 30B), a binarized signal as shown in FIG. 30C is generated. Next, the phase difference between the binarized signal and the recovered clock is detected, and the recovered clock is controlled so that the integral value of the phase difference between the binarized signal and the recovered clock becomes “0”. In this way, a reproduction clock as shown in FIG. 30 (d) is generated. A time error between the rising edge position and the falling edge position of the binarized signal and the rising edge position of the reproduction clock becomes a phase error value.

The phase error value Δt _2Ts3Tm indicates the phase error value at the _start edge position of the 3T mark (the boundary position between the 2T space and the 3T mark), and the phase error value Δ _3Tm4Ts indicates the end edge position of the 3T mark (the 3T mark The phase error values Δt _4Ts2Tm and Δt _2Tm3Ts indicate the phase error values at the start edge position and the end edge position of the 2T mark, respectively. The length of the recording mark can be determined based on the time interval between the rising edge and falling edge of the binarized signal. By detecting and integrating the phase error value for each edge pattern, a distribution of phase error values as shown in FIG. 30E is obtained for each edge pattern. FIG. _30E shows the distribution of the phase error value Δt _2Ts3Tm . The average value of the distribution of phase error values corresponds to the jitter value. The jitter can be optimized by adjusting the start edge position and the end edge position (that is, the shape of the recording pulse) of the recording mark so that the jitter value approaches “0”. Note that the accumulated value of the absolute values of the phase error values, not the average value of the distribution of the phase error values, may be calculated as the jitter value.

[Clock generator]
FIG. 31 shows a configuration example of the clock generator 204 shown in FIG. The clock generator 204 includes a comparator 211, a phase difference detector 212, a low pass filter (LPF) 213, and a voltage controlled oscillator (VCO) 214. The comparator 211 compares the signal level of the analog reproduction signal Asa with a threshold voltage. If the signal level of the analog reproduction signal Asa is higher than the threshold voltage, the comparator 211 sets the output of the comparator 211 to a high level and performs analog reproduction. When the signal level of the signal Asa is lower than the threshold voltage, the output of the comparator 211 is set to a low level. Thereby, the analog reproduction signal Asa is binarized (converted into a binarized signal). The threshold voltage is feedback-controlled so that the integrated value of the binarized signal (output of the comparator 211) becomes “0”. The phase difference detector 212 detects a phase error value PD between the reproduction clock CLK and the binarized signal (output of the comparator 211). The low-pass filter 213 smoothes the output of the phase difference detector 212. The voltage controlled oscillator 214 controls the frequency of the reproduction clock CLK according to the output of the low pass filter 213.

[Jitter detector]
The jitter detection unit 17 illustrated in FIG. 1 calculates a jitter value for each edge pattern by integrating the phase error value PD for each edge pattern of the binarized signal (output of the comparator 211). Note that the jitter detector 17 may calculate the accumulated value of the absolute values of the phase error values as the jitter value instead of the average value of the distribution of the phase error values.

[Relationship between jitter optimization, length difference error value and phase error value]
Next, the relationship between the jitter optimization and the length difference error value and the phase error value will be described with reference to FIG. Here, a case where the length of a recording mark and the length of two spaces adjacent to each other with the recording mark interposed therebetween are “3T” will be described as an example.

In FIG. 32, jitter is optimized, and sample values (y _k−3 , y _k−2 , y _k−1 , y _k ) of the reproduction signal corresponding to the start edge portion of the recording mark are (4.8). , 4.8, 3.0, 1.2), and sample values (y _k−3 , y _k−2 , y _k−1 , y _k ) of the reproduction signal corresponding to the end edge portion of the recording mark are (1.2, 3.0, 4.8, 4.8). In this case, the path B of the pattern PP1 is selected as the most likely state transition sequence at the start edge portion of the recording mark, and the path B of the pattern PP5 is selected as the most likely state transition sequence at the end edge portion of the recording mark. Will be. The length error value Dl is calculated as “−1.6”, and the phase error value Dp is calculated as “0.0”.

  When the shape of the recording pulse is adjusted so as to optimize the jitter, the edge position (that is, the intersection of the signal level “3” and the reproduction signal) at the start edge portion and the end edge portion of the recording mark is the channel clock. It coincides with the cycle TCLK. However, the sample values other than the intersection with the signal level “3” among the sample values of the reproduction signal do not coincide with the expected values of the most probable state transition sequence. This is because the equalization characteristic (boost amount for each frequency band of the input signal) differs between the signal processing sequence for performing the jitter detection process and the signal processing sequence for performing the maximum likelihood decoding process.

  Since the ideal length error value of the recording mark that is optimal for the maximum likelihood decoding process is “0.0”, in the case of FIG. 32, the length target value Dlt is set to “−1.6 <Dlt <0.0. By setting to "", optimization control that is not biased to one of optimization of jitter and optimization of error probability of maximum likelihood decoding processing becomes possible. That is, if a length error value detected when a recording mark formed based on a recording parameter with an optimum jitter is reproduced is “Dlj”, Dlj <Dlt <0 when Dlj <0, and Dlj The length target value Dlt may be set so that 0 <Dlt <Dlj when> 0.

  In addition, since the ideal phase error value of the recording mark that is optimal for the maximum likelihood decoding process is “0.0”, it is detected when the recording mark formed based on the recording parameter that optimizes the jitter is reproduced. The phase target value Dpt may be set so that Dpj <Dpt <0 when Dpj <0, and 0 <Dpt <Dpj when Dpj> 0, where Dpj <0. .

  Note that the length error value is set to a value other than “0” only for a recording pattern (for example, a recording pattern corresponding to a 3T mark) in which the difference in equalization characteristics between the jitter detection process and the maximum likelihood decoding process is the largest. May be set. Even in such a setting, optimization control that is not biased to either optimization of jitter or optimization of error probability of maximum likelihood decoding processing is possible.

  Next, jitter optimization processing and target value calculation processing by the optical disc recording / reproducing apparatus shown in FIG. 1 will be described. Here, for simplification of explanation, it is assumed that the recording conditions are not changed.

[Jitter optimization processing]
First, the recording / playback control unit 502 causes the recording / playback unit 11 to perform a recording operation. The recording / reproducing unit 11 converts a predetermined amount of recording data WD into a recording pulse PW based on the recording parameter, and forms a recording area in the data area of the optical disc 10 based on the recording pulse PW. Next, the recording / playback control unit 502 causes the recording / playback unit 11 to perform a playback operation. The recording / reproducing unit 11 reproduces the analog reproduction signal AS by irradiating a reproduction beam to the recording area formed in the data area of the optical disc 10. The reproduction processing unit 12 generates a reproduction clock CLK based on the analog reproduction signal AS and detects a phase error value PD between the analog reproduction signal AS and the reproduction clock CLK. The jitter detector 17 detects a jitter value based on the phase error value PD. The parameter control unit 503 adjusts the shape of the recording pulse indicated by the recording parameter so that the jitter value detected by the jitter detecting unit 17 approaches “0”. Next, the recording / reproducing control unit 502 causes the recording / reproducing unit 11 to perform a recording operation, and the recording / reproducing unit 11 converts a predetermined amount of recording data WD into a recording pulse PW based on the recording parameter (adjusted recording parameter). Conversion is performed, and a recording area is formed in the data area of the optical disc 10 based on the recording pulse PW. By repeating such processing, an optimum recording parameter for the jitter is detected.

[Target value calculation processing]
First, the recording / reproducing control unit 502 sets the recording parameter detected by the jitter optimization process as the recording parameter of the recording / reproducing unit 11 and then causes the recording / reproducing unit 11 to perform a recording operation. The recording / reproducing unit 11 converts a predetermined amount of recording data WD into a recording pulse PW based on the recording parameter, and forms a recording area in the data area of the optical disc 10 based on the recording pulse PW. Next, the recording / playback control unit 502 causes the recording / playback unit 11 to perform a playback operation. The recording / reproducing unit 11 reproduces the analog reproduction signal AS by irradiating a reproduction beam to the recording area formed in the data area of the optical disc 10. The reproduction processing unit 12 converts the analog reproduction signal AS into a digital reproduction signal DS, and the decoding processing unit 13 performs a maximum likelihood decoding process on the digital reproduction signal DS to generate a binary signal D302. The quality information detection unit 14 detects an edge pattern for each transition edge of the binarized signal D302 and detects a reliability value for each edge pattern. The parameter control unit 503 calculates a length error value and a phase error value for each recording parameter based on the reliability value detected for each edge pattern. Next, the parameter control unit 503 calculates a length target value and a phase target value based on the length error value and the phase error value for each recording pattern. For example, when the length error value is “Dlj”, the parameter control unit 503 sets the length target so that Dlj <Dlt <0 when Dlj <0 and 0 <Dlt <Dlj when Dlj> 0. When the value Dlt is set and the phase error value is “Dpj”, the phase error value Dpt is set so that Dpj <Dpt <0 when Dpj <0 and 0 <Dpt <Dpj when Dpj> 0. Set. Next, the parameter control unit 503 registers the length target value and the phase target value calculated for each recording parameter in the target setting information D603. In this way, it is possible to set the length target value and the phase target value that are not biased to one of the optimization of jitter and the optimization of the error probability of the maximum likelihood decoding process for each recording pattern.

  In addition, in the inner peripheral power calibration area (or outer peripheral power calibration area) of the optical disc 10 instead of the data area of the optical disc 10, a jitter optimization process and a test pattern suitable for jitter detection are used instead of the recording data WD. A target value calculation process may be executed.

[Modified example of clock generator]
Note that the reproduction processing unit 12 may include the clock generator 204a shown in FIG. 33 instead of the clock generator 204 shown in FIG. 33 includes a phase difference detector 221, a low-pass filter 222, a digital / analog converter (DAC) 223, and a voltage controlled oscillator (VCO) 224. As shown in FIG. 34, the phase difference detection unit 221 sequentially acquires a plurality of digital values Q1, Q2,... Constituting the digital reproduction signal DS and determines the polarity of the digital value with respect to a reference value (for example, threshold voltage value). When the polarity of the digital value (for example, digital value Q2) acquired this time is different from the polarity of the digital value (for example, digital value Q1) acquired last time, the average value of the current digital value and the previous digital value ( For example, the average value PD1) is detected. When the current digital value is larger than the previous digital value, the phase difference detection unit 221 outputs an average value (for example, average value PD1, average value DP3 of digital values Q5, Q6) as a phase error value PD. If the current digital value is smaller than the previous digital value, the sign of the average value (for example, the average value Q34 of the digital values Q3, Q4, the average value Q78 of the digital values Q7, Q8) is inverted and the inverted value (For example, the inverted values PD2 and PD4) are output as the phase error value PD. The low-pass filter 222 smoothes the output of the phase difference detection unit 221. Thereby, the low-pass filter 222 outputs a signal indicating a phase error curve of the digital reproduction signal DS. The digital / analog converter 223 converts the output of the low-pass filter 222 into a control signal (analog signal). The voltage controlled oscillator 224 adjusts the frequency of the reproduction clock CLK according to the voltage level of the control signal from the digital / analog converter 223. For example, in the case of FIG. 34, since the output of the low-pass filter 222 (ie, the phase error curve) has a positive polarity with respect to the reference value, the voltage controlled oscillator 224 increases the frequency of the recovered clock CLK.

  The optical disk recording / reproducing apparatus shown in FIG. 1 does not have to include the jitter detection unit 17.

(Other embodiments)
The write and verify operation and the recording parameter optimization process in the power calibration area may be used in combination. In the recording parameter optimization process in the power calibration area, the recording / reproducing unit 11 may convert the test pattern into the recording pulse WP instead of the recording data WD based on the recording parameter. In the test pattern, the combination of the mark section and the space section necessary for optimizing the recording parameter occurs at the same frequency, and the DC component (DSV) included in the test pattern is “0”. Even in such a configuration, it is possible to suppress the time spent for optimization (adjustment) of the recording parameters from concentrating at the start of activation of the optical disc recording / reproducing apparatus, so that it is more than the case where only the optimization processing of the recording parameters is executed. Start-up time can be shortened.

  The patterns PP1 to PP8 do not correspond to the start edge pattern 2Ts2Tm and the end edge pattern 2Tm2Ts, but the reliability values of the start edge pattern 2Ts2Tm and the end edge pattern 2Tm2Ts may be detected by other decoding methods. .

  Further, the number of recording patterns for calculating the error value may be determined in consideration of the influence of the recording mark and space on the optical disc 10 on the error value. For example, in the above example, the 5T mark to the longest mark are combined into one “5T mark or more”, and the 5T space to the longest space are combined into “5T space or more” as an error value (length error). Value and / or phase error value) is expressed, but all the recording patterns expressed by all the marks from the shortest mark to the longest mark and all the spaces from the shortest space to the longest space An error value may be calculated.

  Or, if the error value of the recording mark can be detected without being affected by the space positioned before and after the recording mark (the length of the recording mark is the same even if the length of the space positioned before and after the recording mark is different) If the error values of the recording marks are the same), the four recording patterns (2T mark, 3T mark, 4T mark, and 5T mark) expressed only by the recording mark instead of the 57 recording patterns. The recording parameters may be adjusted by calculating error values for the above. In this way, by reducing the number of recording patterns to be detected as error values, it is possible to reduce the calculation amount of error values and the storage area for reliability values.

  The controller 15 may be realized by a dedicated circuit (hardware) or may be realized as a CPU function. For example, the CPU mounted on the optical disc recording / reproducing apparatus may control the write and verify operation according to a recording / reproducing program (a program for executing a write and verify operation). The recording / reproducing program may be stored in a storage unit (not shown) provided inside the optical disc recording / reproducing apparatus, or may be downloaded by a user from a specific website on the Internet for a fee or free of charge. You may install in an optical disk recording / reproducing apparatus. The installed recording / reproducing program is stored in a storage unit (not shown) provided in the optical disc recording / reproducing apparatus. Further, the recording / reproducing program may be stored in a computer-readable recording medium (for example, a flexible disk, a CD-ROM, a DVD-ROM, etc.). In this case, the recording / reproducing program stored in the recording medium may be installed in the optical disc recording / reproducing apparatus by the input device.

  The optical disc 10 is an optical disc such as a CD (Compact Disc), a DVD (Digital Versatile Disc), a DVD-RAM (Digital Versatile Disc-Random Access Memory), a BD (Blu-ray Disc), or an MO (Magneto-Optical Disc). ), And information recording for recording digital signals by changing the length or phase of information formed according to the polarity interval of digital signals (the length of continuous recording codes (0 or 1)) It may be a medium.

  In the above description, the case where the minimum polarity inversion interval of the recording code (recording data WD) is “2” and the equalization method is PR (1, 2, 2, 1) equalization is taken as an example. It is not limited to this. For example, when the minimum polarity inversion interval such as 8-16 modulation code used for DVD is “3”, there are six states at time k due to PR (1, 2, 2, 1) equalization. To do. In this case, a state transition rule that restricts eight possible state transitions to six states at time k + 1 may be used. Also, a combination of a recording code having a minimum polarity inversion interval of “2” or “3” and PR (C0, C1, C1, C0) equalization, or a minimum polarity inversion interval of “2” or “3”. The present invention can also be applied to a combination of a recording code and PR (C0, C1, C2, C1, C0) equalization (C0, C1, C2 are arbitrary positive numbers).

  As described above, the above-described optical disc recording / reproducing apparatus can be used as a DVD driver, a DVD recorder, a BD recorder, and the like because it can shorten the startup time and improve the recording quality.

DESCRIPTION OF SYMBOLS 11 Recording / reproducing part 12 Reproduction | regeneration processing part 13 Decoding processing part 14 Quality information detection part 15 Controller 16 Memory 17 Jitter detection part 101 Buffer 102 Recording compensation part 103 Laser drive part 104 Optical head 201 Amplifier 202 Automatic gain controller 203 Waveform equalizer 204 Clock generator 205 Analog / digital converter 301 Shaping unit 302 Maximum likelihood decoding unit 401 Reliability calculation unit 402 Edge pattern detection unit 403 Reliability storage unit 404 Transfer unit 501 Mode control unit 502 Recording / playback control unit 503 Parameter control unit

Claims (8)

A predetermined amount of recording data to be recorded on the optical disc is converted into a recording pulse based on the recording parameter indicating the correspondence between the length of the mark section of the recording data and the shape of the recording pulse, and based on the recording pulse, the recording pulse A recording operation for irradiating the data area of the optical disc with a recording beam to form a recording area composed of a plurality of marks and spaces in the data area, and a reproducing beam for irradiating the recording area formed in the data area by the recording operation A recording / playback unit that alternately repeats a playback operation for generating an analog playback signal,
A reproduction processing unit for converting the analog reproduction signal into a digital reproduction signal;
A decoding processor that performs maximum likelihood decoding on the digital reproduction signal to generate the most likely binary signal;
For each transition edge of the binarized signal, an edge pattern expressed by a combination of the mark section and the space section of the binarized signal adjacent to each other with the transition edge interposed therebetween is detected, and the edge pattern is detected for each edge pattern. A quality information detection unit for detecting a reliability value indicating reliability of the result of the corresponding maximum likelihood decoding process;
In the period from the start of the reproducing operation by the recording / reproducing unit to the start of the recording operation by the recording / reproducing unit, the shape of the recording pulse indicated by the recording parameter is determined based on the reliability value detected for each edge pattern. An optical disc recording / reproducing apparatus comprising: a control unit for adjustment. In claim 1,
An information storage unit for storing a plurality of recording parameters each corresponding to a different recording condition;
The control unit selects a recording parameter corresponding to a current recording condition from a plurality of recording parameters stored in the information storage unit, and based on the reliability value detected for each edge pattern, Adjust the shape of the recording pulse shown in the recording parameters corresponding to the recording conditions,
The optical disc recording / reproducing apparatus, wherein the recording / reproducing unit performs the recording operation based on a recording parameter selected by the control unit. In claim 1 or 2,
The control unit, based on a reliability value detected for each edge pattern, by a combination of a mark section of the binarized signal and two space sections of the binarized signal adjacent to each other across the mark section An error value of the recording pattern is calculated for each recording pattern to be expressed, and the recording parameter indicates that at least one of the error values calculated for each recording pattern approaches a preset target value. An optical disc recording / reproducing apparatus characterized by adjusting the shape of the recorded pulse. In claim 3,
The control unit determines whether a difference value between the error value and the target value is larger than an improvement reference value for each recording pattern, and the difference value is determined to be larger than the improvement reference value. An optical disc recording / reproducing apparatus, wherein the shape of a recording pulse indicated by the recording parameter is adjusted so that an error value of at least one recording pattern of the recording patterns approaches the target value. In claim 4,
The control unit determines whether or not a difference value between the error value and the target value is larger than a defect reference value for each recording pattern, and detects a recording pattern in which the difference value is larger than the defect reference value. In this case, the recording / reproducing unit is configured so that a predetermined amount of recording data recorded by the previous recording operation by the recording / reproducing unit is re-recorded in the alternate sector of the optical disc by the next recording operation by the recording / reproducing unit. Control
The optical disc recording / reproducing apparatus, wherein the defect reference value is larger than the improvement reference value. In claim 3,
An information storage unit that stores a plurality of recording parameters each corresponding to a different recording condition and a plurality of target values each corresponding to a different recording condition;
The control unit selects a recording parameter and a target value corresponding to a current recording condition from a plurality of recording parameters and a plurality of target values stored in the information storage unit, and calculates an error calculated for each recording pattern Adjusting the pulse shape of the recording pulse indicated in the recording parameter corresponding to the current recording condition so that at least one of the values approaches a target value corresponding to the current recording condition;
The optical disc recording / reproducing apparatus, wherein the recording / reproducing unit performs the recording operation based on a recording parameter selected by the control unit. In claim 1,
The control unit instructs the quality information detection unit to transfer a reliability value of an edge pattern to be used for adjusting the recording parameter among reliability values detected for each edge pattern,
The optical information recording / reproducing apparatus, wherein the quality information detection unit transfers the reliability value of the edge pattern specified by the control unit among the reliability values detected for each edge pattern to the control unit. In claim 1,
The quality information detection unit
The first index value indicating the probability of the first state transition sequence determined to be most likely by the maximum likelihood decoding process and the second state determined to be the second most likely by the maximum likelihood decoding process A reliability calculation unit that calculates a second index value indicating the probability of the transition sequence, and calculates the reliability value based on a difference value between the first and second index values;
An edge pattern detection unit that detects the edge pattern for each transition edge of the binarized signal;
An optical disk recording / reproducing apparatus, comprising: a reliability storage unit that stores the edge value detected by the edge pattern detection unit in association with the reliability value calculated by the reliability calculation unit.

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