JP4042054B2 - Recording condition setting method, information recording apparatus using the same, and program - Google Patents

Description

  The present invention relates to a recording condition setting method, an information recording apparatus using the same, and a program, and in particular, a recording condition setting method for satisfactorily forming a plurality of recording marks including a recording mark near the optical diffraction limit, and The present invention relates to an information recording device and a program.

  In recent years, large-capacity optical disks represented by DVD and the like have become widespread. When recording information on an optical disc, a recording laser beam is focused on the information recording surface of the optical disc by an information recording optical disc apparatus to form a recording mark. When information is reproduced from the optical disc, the reproduction laser beam is condensed on the information recording surface of the optical disc by the information reproducing optical disc device, and the reflected light modulated by the recording mark is detected to reproduce the information. As long as the optical disk is an optical disk apparatus that reproduces an optical disk of the same standard, recorded information can be reproduced even by an apparatus different from the optical disk apparatus that performed the recording.

  There are two types of methods for recording information on an optical disc: a mark position recording method in which information is provided at the position of a recording mark, and a mark edge recording method in which information is provided at the front and rear ends of the recording mark. When both methods are compared, the mark edge recording method is a recording method suitable for higher density, but the length of the recording mark is required to be controlled with particularly high accuracy.

  In a writable optical disk, a recording mark is generally formed by a temperature rise of a recording film due to laser light irradiation. The length of the recording mark varies depending on the composition of the disk including the dye used for the optical disk, metal, track pitch, etc., and conditions such as the recording clock and linear velocity. Therefore, in order to control the recording mark length with high accuracy, the recording conditions including the intensity, pulse shape and pulse width (hereinafter referred to as recording strategy) of the pulsed light of the laser light irradiated on the optical disc are determined according to the configuration of the disc and It is necessary to set appropriately according to the linear velocity.

  FIG. 17 shows an example of a waveform of a laser output when a recording mark is formed on an optical disc. When forming the recording mark, for example, the laser output is controlled by any one of the waveform patterns from (a) to (d) in the same figure, and the laser beam applied to the recording surface of the optical disk is controlled. In FIG. 2A, a recording mark is formed by applying a laser beam having a constant output for a time corresponding to the length of the recording mark. In FIGS. 5B and 5C, a recording mark having a desired mark length is formed by n or (n−1) pulse trains. In FIG. 4D, the laser output is increased in correspondence with the leading and trailing ends of the recording mark by a non-pulse train to form a recording mark having a desired mark length.

  In general, a recording mark is formed to have a length that is an integral multiple of T, where T is a period of a clock (channel clock) serving as a reference when recording / reproducing is performed. Each recording mark is composed of, for example, one of recording marks having a length of 2T to 8T in the (1, 7) RLL method in which encoding is 2/3 conversion. Here, 2T is composed of a signal having a period composed of a space twice as long as the period T of the channel clock and a mark twice as long, and 8T is eight times as long as the period T of the channel clock. It is composed of a signal having a period composed of a space having a length and a mark having a length eight times longer.

  In the optical disc apparatus, prior to recording on the optical disc, after the leading width Ttop of the writing pulse shown in FIG. 17, the intermediate pulse width Tmp (or Tw), the trailing end width Tlp of the writing pulse, and the cooling control time are set. An end cooling width Tcl or the like is set as a recording strategy parameter. Among these parameters, parameters that have a strong influence on the quality of recording mark formation vary depending on the type of the medium, a medium having a large influence of the leading width Ttop, a medium having a large influence of the trailing edge cooling width Tcl, and the trailing edge width. A medium having a large influence of Tlp or a medium in which those parameters are combined and influenced is known. In the mark edge recording method, since the head and the rear end of the recording mark need to be recorded satisfactorily, the head width Ttop and the rear end cooling width Tcl are often important parameters.

  In an optical disc apparatus, the recording strategy is usually configured according to a certain rule because of the restrictions on the circuit scale and the target medium. For example, when recording is performed with a recording strategy set to a certain time width, the recording width is formed by setting the leading width Ttop to the same value (or equivalent to Ttop). Taking the (1, 7) RLL system as an example, each of the configuration marks 2T to 8T is recorded with a recording strategy in which the leading pulse width Top and the trailing edge cooling width Tcl are set in common to the marks.

  As a method for appropriately setting a recording strategy, a β method employed in a DVD rewritable system including a DVD-R is known. FIG. 18 shows an example of a signal waveform used in the β method. In the β method, a long mark (for example, 11T) and a space, and a short mark (for example, 3T) and a space are recorded while changing the recording conditions, and the asymmetry value (β value) is obtained by reproducing the signal. Set the recording conditions including.

As shown in FIG. 18, the β value is obtained by first obtaining the reference point Ref from the reproduction waveforms of the 11T and 3T recording marks, then setting the 11T peak level as A and the 11T bottom level as B.
β = 0.5 × (A−B) / (A + B)
Is calculated by β value correlates with jitter σ, which is an evaluation index of recording signal quality, and by setting recording conditions so that β value is within a predetermined range, formation of good recording marks with little jitter in the reproduction signal Is possible.

In general, when the jitter σ is 15% or more, the error of the reproduced signal cannot be corrected even if error correction processing is performed, so the jitter σ needs to be suppressed to 15% or less. For example, as the correlation between the jitter σ and the bit error rate BER, there is known a correlation in which the bit error rate BER = 10 ⁻⁴ and the jitter σ = 12.8%. Deterioration factors of the jitter σ include a recording power setting error, a recording strategy setting error, a focus setting error, a tilt setting error, and the like.

  In the current optical disk apparatus, even when all the recording conditions are set to optimum values, the jitter σ is reduced only to about 8%. Since the jitter degradation allowed for the setting error of the recording power and the recording strategy is about 2%, when setting the recording condition, the parameters of the recording power and the recording strategy are set so that the jitter σ is 10% or less. It is desirable to adjust.

  As a technique for optimizing the recording conditions, Japanese Patent Laid-Open No. 2000-30254 (Patent Document 1) determines the theoretical mark length of the longest mark with respect to the recording power, and all the recording marks with respect to the recording strategy. A technique for selecting a recording strategy that minimizes the included jitter or the jitter of only the shortest recording mark is described.

In addition, as a high-density reproduction technology in an optical disc apparatus, PRML (Partial Response Maximum Likelihood) technology (“1994, Annual Conference of Television Society (ITE'94)) combining partial response waveform equalization and maximum likelihood detection. Preliminary book, pages 287 to 288 (Non-Patent Document 1)) is known. In this technique, the maximum likelihood detection is performed after correcting the reproduction signal by waveform equalization in order to maximize the characteristics of the maximum likelihood detector in consideration of the reproduction channel. When the PRML technology is used, there is an advantage that high-density reproduction performance can be ensured even if the reproduction resolution of the shortest mark is not sufficient.
JP 2000-30254 A 1994, Annual Conference of the Institute of Television Engineers (ITE'94), 287-288 pages

  Here, FIG. 19 shows an example (a) of recording data and an example (b) of a reproduction signal waveform of the recording data. A solid line 22 in FIG. 5B shows a reproduction signal waveform when the recording density is higher than that indicated by the dotted line 21. As the recording density is further increased and the recording mark length recorded on the disk becomes shorter, as shown in FIG. 5B, the amplitude of the reproduction signal is reduced and a recording mark is formed with a short recording mark. Nevertheless, the signal slice level 23 for measuring the mark position may be lower. When the amplitude of the reproduction signal is lower than the slice level 23, there arises a problem that the positions of the front end and the rear end of the recording mark cannot be accurately measured.

  In particular, with a recording mark having a length close to the optical diffraction limit, sufficient reproduction signal amplitude cannot be obtained, and the influence of intersymbol interference increases, so that the accuracy of detection of jitter and asymmetry values decreases. For this reason, it is difficult to optimize the recording strategy by directly using the reproduction signal in the conventional method using jitter and the method using the asymmetry value including the above-mentioned Patent Document 1.

  FIG. 20 shows an optical disk on which an optical head having a laser wavelength of 405 nm and a numerical aperture NA = 0.85 is mounted, and a reproduction eye pattern obtained by performing recording / reproduction with a phase change disk having a cover layer thickness (substrate thickness) of 0.1 mm. The example of a waveform is shown. FIG. 6A shows a reproduction eye pattern when recording is performed at a recording density at which the recording mark length of the shortest mark in the modulation code is 0.166 μm, and FIG. A reproduction eye pattern when recording is performed at a recording density of 148 μm is shown, and FIG. 10C shows a reproduction eye pattern when recording is performed at a recording density where the recording mark length of the shortest mark is 0.125 μm. . As shown in FIGS. 9A to 9C, it can be seen that as the recording mark length of the shortest mark becomes shorter, that is, as the recording density becomes higher, the waveform separation becomes impossible at the short mark portion with the amplitude center. .

  FIG. 21 shows the relationship between the shortest mark length and jitter. It can be seen that the jitter of the reproduction signal increases as the recording density is increased and the shortest mark length in the modulation code is shortened. In particular, the ratio between the reproduction signal amplitude of the shortest mark and the reproduction signal amplitude of the longest mark in the modulation code is 10% or less, and the shortest mark length is shorter than the mark length indicated by the dotted line in FIG. It can be seen that the mark reproduction signal has a jitter exceeding 15%. It is known that when the jitter exceeds 15%, the dispersion of each recording mark is large and the window exceeds the window allowed for each mark. This is because the inter-symbol interference is caused by the insufficient separation of the reproduced signal, especially at the short recording mark, and the mark generation accuracy that can be detected when the recording density is low is accurately detected using jitter. Indicates that it will not be possible. Similarly, in the β method, the detection accuracy of the asymmetry value of the shortest mark is lowered, which indicates that it is impossible to accurately determine whether or not the recording mark can be formed satisfactorily.

  The PRML technique is effective when recording marks are recorded at a high density to such an extent that a sufficient reproduction signal amplitude cannot be obtained. However, since the PRML technology requires a separate PRML detection circuit, the circuit configuration is complicated. In the PRML technique, the bit error rate is calculated by comparing the known data with the PRML detected recording / reproduction data. Therefore, the comparison source data needs to be known, and jitter and asymmetry values are used. In contrast, there is a drawback that it is difficult to handle universally.

  The present invention solves the above-mentioned problems, and even when recording is performed at a recording density that is so high that the reproduction signal of the shortest mark cannot be directly used, the recording conditions can be set easily and with high accuracy. An object of the present invention is to provide a recording condition setting method that can be used, an information recording apparatus using the same, and a program.

  In order to achieve the above object, a recording condition setting method according to a first aspect of the present invention is a recording condition setting method for an information recording medium, and is one recording length unit from the shortest mark in a modulation code used for information recording. The first test mark that is longer than the shortest mark length is recorded under a plurality of recording conditions, and the first recording condition is selected based on a plurality of reproduction signals obtained by reproducing the recorded first test mark. 2. One or more second test marks selected from marks having a length longer than the recording unit length and not longer than the longest mark are recorded under a plurality of recording conditions, and the recorded second test mark is reproduced. The second recording condition is selected based on the plurality of reproduced signals, and the recording condition of the shortest mark is obtained based on the first and second recording conditions.

  In the recording condition setting method according to the first aspect of the present invention, for each of the first and second test marks recorded under a plurality of recording conditions, a recording condition for obtaining a good signal reproduced from the test mark is obtained. Based on the recording conditions that can favorably form the second test mark, for example, the recording conditions that favorably form the shortest mark are determined using linear estimation interpolation. For this reason, even when it is not possible to directly determine a recording condition that can satisfactorily form the shortest mark from the reproduction signal of the shortest mark because the recording density is high, the recording condition of the shortest mark can be easily determined.

  According to a first aspect of the present invention, there is provided a recording condition setting method for recording on an information recording medium in which the reproduction amplitude of the shortest mark is 10% or less of the reproduction amplitude of the longest mark and a reproduction signal including a reproduction signal of the shortest mark. This can be applied to recording on an information medium having a jitter of 15% or more. In these cases, the quality of the signal reproduced from the shortest mark is poor and the recording conditions cannot be obtained directly from the reproduced signal, but a longer recording mark can be formed better than the recording condition obtained directly from the reproduced signal. Based on the possible recording conditions, the recording conditions for the shortest mark can be set.

  In the recording condition setting method of the first aspect of the present invention, the plurality of recording conditions are set to at least one of a laser power of a recording laser, a leading pulse width, an intermediate pulse width, a trailing edge pulse width, and a trailing edge cooling width. Is preferably obtained as variable. Of these parameters, the recording mark can be satisfactorily formed even for the shortest mark by appropriately setting a parameter having a large influence when recording on the recording medium.

  In the recording condition setting method according to the first aspect of the present invention, the first and second recording conditions are preferably selected based on asymmetry or jitter of the reproduction signal. The first and second recording conditions can be selected by a method similar to the conventional method based on the reproduction signals of the first and second test patterns.

  A recording condition setting method according to a second aspect of the present invention is a recording condition setting method for an information recording medium, wherein at least the shortest mark is recorded at a plurality of recording densities in which the information recording density is lower than the recording density during normal recording. Recording test marks, reproducing the recorded test marks, obtaining recording conditions for obtaining a good reproduction signal at each of the plurality of recording densities, and recording at the recording density at the time of normal recording The mark recording condition is obtained based on the plurality of recording densities and the recording condition under which the good reproduction signal is obtained.

  In the recording condition setting method according to the second aspect of the present invention, a test mark including at least the shortest mark in the modulation code is changed in the recording condition in each of a plurality of recording densities with a recording density lower than that during normal recording. Based on the reproduction signal, a recording condition for recording on the information recording medium and satisfactorily forming a recording mark of each mark length included in the test mark is obtained. Based on the relationship between the recording conditions at a plurality of recording densities, at least the recording conditions during normal recording of the shortest mark are obtained by estimation. For this reason, even when the recording condition cannot be set by directly using the reproduction signal of the shortest mark during normal recording, the recording condition of the shortest mark can be recorded by using the recording condition obtained by lowering the recording density. Conditions can be easily obtained.

  In the recording condition setting method according to the second aspect of the present invention, the plurality of recording densities are set to a channel clock having a longer period than a channel clock used for normal information recording, and recording used for normal information recording. It is preferable to obtain at least one of linear speeds higher than the linear speed of the medium. In this case, a plurality of recording densities lower than those during normal recording can be easily obtained.

  According to the recording condition setting method of the second aspect of the present invention, at the recording density at the time of normal recording, the reproduction amplitude of the shortest mark is 10% or less of the reproduction amplitude of the longest mark, and the recording density at the time of normal recording For a plurality of recording densities smaller than the above, it is preferable that the reproduction amplitude of the shortest mark is 10% or more of the reproduction amplitude of the longest mark. In this case, the reproduction condition of the shortest mark when the recording density is lowered is directly used to obtain a recording condition that can satisfactorily form the shortest mark at the recording density, and the shortest mark during normal recording is obtained using them. It is possible to set a recording condition that allows favorable mark formation.

  In the recording condition setting method according to the second aspect of the present invention, the recording condition of the shortest mark is preferably obtained by approximation of a quadratic function. By approximating the relationship of recording conditions that can satisfactorily form the shortest marks at a plurality of recording densities with a quadratic curve, it is possible to obtain the recording conditions that can satisfactorily form the shortest marks during normal recording.

In the recording condition setting method of the present invention, the shortest mark length includes the numerical aperture NA of the condenser lens that forms a light spot on the information recording medium, the light source wavelength λ, the substrate thickness d of the information recording medium, and the constant α. The following formula defined by:
Shortest mark length ≧ (α / d) × λ / (4 × NA) (where 1.0 <α / d <1.2)
It is preferable to satisfy. When the shortest mark length is set in the vicinity of the optical diffraction limit, the reproduction signal amplitude of the shortest mark is small and the reproduction signal cannot be directly used to determine the recording condition of the shortest mark. Even in such a case, it is possible to easily obtain a recording condition that allows easy formation of the shortest mark.

  In the recording condition setting method of the present invention, the numerical aperture NA is 0.6 or more and 0.7 or less, the light source wavelength λ is 390 nm or more and 410 nm or less, the substrate thickness of the optical disk to be recorded is 0.6 mm, and the lower limit of the shortest mark length. Can be 145 nm.

  In the recording condition setting method of the present invention, the numerical aperture NA is 0.7 or more and 0.85 or less, the light source wavelength λ is 390 nm or more and 410 nm or less, the substrate thickness of the optical disk for recording is 0.1 mm, and the lower limit of the shortest mark length. Can be 120 nm.

  An information recording apparatus according to a first aspect of the present invention is an information recording apparatus for optically recording information on an information recording medium, and recording condition setting means for setting recording conditions for recording information on the information recording medium And adopting a plurality of recording conditions set by the recording condition setting means, a first test mark that is longer by one recording length unit than the shortest mark in the modulation code used for information recording, and 2 shorter than the shortest mark length. Recording means for recording one or more second test marks selected from marks having a length longer than the recording unit length and not longer than the longest mark on the information recording medium, and the first test mark from the information recording medium And reproduction means for reproducing the second test mark and generating a reproduction signal, and a first recording condition based on the reproduction signal of the first test mark, and the reproduction signal of the second test mark. And a signal processing means for selecting a second recording condition based on the first recording condition, and a recording for setting the recording condition for the shortest mark based on the first recording condition and the second recording condition selected by the signal processing means. And a condition setting means.

  In the information recording apparatus according to the first aspect of the present invention, the signal processing means selects a recording condition for improving the signal reproduced from the test mark for each of the first and second test marks recorded under a plurality of recording conditions. To do. The recording condition setting means sets a recording condition that allows the shortest mark to be formed satisfactorily using, for example, linear estimation interpolation, based on the selected recording condition that allows the first and second test marks to be formed satisfactorily. For this reason, the information recording apparatus simply sets the recording condition of the shortest mark even when the recording density is high and the recording condition that can satisfactorily form the shortest mark from the reproduction signal of the shortest mark cannot be directly obtained. be able to.

  An information recording apparatus according to a second aspect of the present invention is an information recording apparatus that optically records information on an information recording medium, and has a plurality of recording densities in which the information recording density is lower than the recording density during normal recording. Recording means for recording a test mark including at least the shortest mark; reproduction means for reproducing a test mark recorded by the recording means to generate a reproduction signal; and for each of the plurality of recording densities, A signal processing means for obtaining a recording condition for obtaining a good reproduction signal from the inside, a recording condition for at least the shortest mark to be recorded at the recording density at the time of the normal recording, the plurality of recording densities, and the good reproduction signal. Recording condition setting means for setting based on the set recording conditions.

  In the information recording apparatus according to the second aspect of the present invention, the signal processing means changes the recording condition of at least the test mark including the shortest mark in the modulation code at each of a plurality of recording densities having a recording density lower than that during normal recording. Then, recording is performed on the information recording medium, and a recording condition that can satisfactorily form a recording mark of each mark length included in the test mark is obtained based on the reproduction signal. The recording condition setting unit obtains at least a recording condition during normal recording of at least the shortest mark based on the relationship between the recording conditions at a plurality of recording densities. For this reason, the information recording apparatus uses the recording condition obtained by lowering the recording density even when the recording condition cannot be set by directly using the reproduction signal of the shortest mark during normal recording. The recording conditions for the shortest mark can be set easily.

  A program according to a first aspect of the present invention is a program for setting a recording condition for recording information on an information recording / reproducing medium, and is an initial recording preset in the information recording medium or information recording / reproducing apparatus. A step of setting a plurality of test recording conditions based on the conditions, and a recording mark that is one recording length unit longer than the shortest mark in the modulation code used for information recording under each of the set test recording conditions (First test mark) and data including one or more recording marks (second test mark) selected from marks having a length that is two recording unit lengths longer than the shortest mark and shorter than the longest mark. And recording the signal, reproducing the recorded signal, detecting asymmetry or jitter of the reproduced signal reproduced, and Extracting one test recording condition for each of the first test mark and the second test mark based on an absolute value of asymmetry or jitter detected for each of the recording test conditions; and obtaining for the first test mark And determining a recording condition for the shortest mark based on the test recording condition obtained and the test recording condition obtained for the second test mark.

  The program according to the first aspect of the present invention directly controls the recording conditions under which the shortest mark can be satisfactorily formed from the reproduction signal of the shortest mark due to the high recording density under the control of a computer that controls an apparatus for reading and writing information recording / reproducing media. Even when it cannot be obtained automatically, the recording condition of the shortest mark can be easily obtained.

  Alternatively, in place of the above, another program according to the first aspect of the present invention is a program for setting recording conditions for recording information on an information recording / reproducing medium, the information recording medium or the information recording medium A first step of selecting a plurality of test recording conditions based on an initial recording condition or a modified recording condition set in advance in the playback device, and is used for information recording under the selected test recording condition. 1 selected from a recording mark (first test mark) that is one recording length unit longer than the shortest mark in the modulation code, and a mark that is longer than the shortest mark by two recording unit lengths and shorter than the longest mark. A second step of recording a signal using data including two or more recording marks (second test marks), reproducing the recorded signal, and reproducing the reproduced signal A third step of detecting asymmetry or jitter, and determining the quality of each test recording condition based on the absolute value of the asymmetry or jitter detected for each of the test recording conditions, the first test mark and the second test mark If there is no test recording condition determined to be good, the test recording condition is determined to be good for both the first test mark and the second test mark by returning to the second step and reselecting the test recording condition. When there is a fourth step, the process proceeds to the next step, a test recording condition obtained for the first test mark and determined to be good, and a test recording condition obtained for the second test mark and determined to be good. And a fifth step of sequentially determining a recording condition of the shortest mark based on the fifth step.

  In another program according to the first aspect of the present invention, when it is determined in the fourth step that there is a test recording condition determined to be good for both the first test mark and the second test mark, the fifth step For example, when setting the recording conditions by changing the values of the two parameters of the recording conditions within a predetermined range, the second step does not have to be executed for all the combinations. As compared with the case where the second step is executed, the time required for setting the recording condition can be shortened.

  A program according to a second aspect of the present invention is a program for setting a recording condition for recording information on an information recording / reproducing medium, and a plurality of recordings whose information recording density is lower than that during normal recording. A step of setting a density; a step of selecting a plurality of test recording conditions for each of the plurality of recording densities based on an initial recording condition preset in the information recording medium or the information recording / reproducing apparatus; For each recording density, recording a signal including a mark having a predetermined recording unit length under the selected plurality of test recording conditions, and reproducing the recorded signal for each of the plurality of recording densities Detecting asymmetry or jitter of the reproduced signal reproduced, and for each of the plurality of recording densities, Selecting one test recording condition for the mark having the predetermined recording unit length based on the absolute value of asymmetry or jitter detected for each of the test recording conditions, the plurality of recording densities, and the recording density And setting the recording condition of the mark having the predetermined recording unit length at the recording density at the time of normal recording based on the test recording condition selected for each of the above.

  The program according to the second aspect of the present invention records, for example, the shortest mark as a mark having a predetermined recording unit length on an information recording medium under the control of a computer that controls an apparatus for reading and writing the information recording / reproducing medium. Even in the case of normal recording, when the recording condition cannot be set by directly using the reproduction signal of the shortest mark, the recording condition of the shortest mark obtained by lowering the recording density is used. The recording condition of the shortest mark can be easily obtained.

  Alternatively, another program according to the second aspect of the present invention is a program for setting a recording condition for recording information on an information recording / reproducing medium, and the information recording density is set at the time of normal recording. A first step of setting the recording density to one of a predetermined number of recording densities lower than the recording density, and an initial recording condition or a modified recording condition preset in the information recording medium or information recording / reproducing apparatus A second step of selecting a plurality of test recording conditions; a third step of recording a signal including a mark having a predetermined recording unit length under the selected plurality of test recording conditions; and A fourth step of reproducing and detecting asymmetry or jitter of the reproduced signal reproduced, and an absolute value of the asymmetry or jitter detected for each of the test recording conditions On the basis of the test recording conditions, the test recording conditions are determined to be good. If there is no test recording condition determined to be good, the process returns to the second step and the plurality of test recording conditions are selected again. At some point, when all of the predetermined number of recording densities have not been selected, the process returns to the first step to select another recording density and all of the predetermined number of recording densities have been selected. The predetermined recording unit at the recording density at the time of the normal recording, based on the fifth step that shifts to the next step when it is, the plurality of recording densities, and the recording conditions selected for each of the recording densities And a sixth step of setting recording conditions for marks having a length.

  In another program according to the second aspect of the present invention, in order to determine whether or not there is a test recording condition determined to be good for both the first test mark and the second test mark in the fifth step, for example, recording is performed. When setting the recording conditions by changing the values of the two parameters of the conditions within a predetermined range, the third step does not have to be executed for all combinations, so the second step is executed for all combinations. Compared to the case, the time required for setting the recording condition can be shortened.

According to the first aspect of the present invention, a recording condition setting method, an information recording apparatus using the same, and a program are provided on the basis of the reproduction signals of the first and second test marks. Recording conditions that allow good reproduction (formation) of the mark are selected, and the recording condition of the shortest mark is obtained based on the selected recording conditions of the first and second test marks. For this reason, the ratio between the amplitude of the reproduction signal of the longest mark and the amplitude of the generation signal of the shortest mark is about 10% or less, and the recording condition cannot be obtained by directly using the reproduction signal of the shortest mark. The recording condition of the shortest mark can be easily obtained.
In addition, the second viewpoint recording condition setting method, the information recording apparatus using the method, and the program each include a shortest mark in at least a modulation code in each of a plurality of recording densities having a recording density lower than that during normal recording. Based on the reproduction signal, a recording condition that can satisfactorily form a recording mark of each mark length included in the included test mark is obtained, and at least the shortest mark is recorded during normal recording based on the relationship of the recording conditions at a plurality of recording densities. The condition is obtained by estimation. For this reason, the recording condition of the shortest mark can be obtained without adding a new detection function even when the recording condition cannot be set directly using the reproduction signal of the shortest mark during normal recording. .

  Hereinafter, with reference to the drawings, the present invention will be described in more detail based on exemplary embodiments of the present invention. FIG. 1 shows an outline of the processing of the recording condition adjusting method of the first embodiment of the present invention. Prior to recording information on an optical disc (information recording medium), an optical disc apparatus that records and reproduces information sets recording conditions including parameters of the recording strategy according to the procedure shown in FIG.

  First, the prescribed values of each parameter of the recording strategy including the recording power used for recording are read from the optical disk device or the recording target optical disk itself (step S11). These specified values are set in advance by the manufacturer as recording conditions suitable for the optical disc to be recorded, for example, and are stored in a storage device in the optical disc apparatus. Alternatively, it is recorded in a predetermined area of the optical disc. In step S11, for example, parameters such as the head width Ttop and the rear end cooling width Tcl in the (n-1) T pulse train similar to the waveform shown in FIG. Recording power suitable for recording is read out.

  Next, a predetermined recording pattern is recorded on the optical disc while changing the recording conditions. In the predetermined recording pattern used for recording, the ratio of the amplitude of the reproduction signal of the longest mark (Lmax) and the amplitude of the reproduction signal of the shortest mark (Lmin) in the data after recording modulation limited in run length is approximately 10%. The shortest mark is a recording mark (first test mark) that is at least 1T longer than the shortest mark, and a recording mark (second test mark) that is longer than the shortest mark by 2T or more and less than the longest mark. . In step S12, for example, the specified recording power read in step S11 and the specified start width Ttop in the (n-1) T pulse train are varied within a range of ± 0.15T, and the recording conditions are changed for each sector. Then, a predetermined recording pattern is recorded on the optical disk in units of 2048 bytes / sector.

Next, the predetermined recording pattern recorded in step S12 is reproduced, and the reproduction signal having the shortest mark length is removed from the predetermined recording pattern, and an asymmetry value is calculated for each recording mark length (step S13). When the asymmetry value is calculated, the recording power that allows good reproduction of the recording mark and the parameters of the recording strategy for each recording mark length excluding the shortest mark length are determined from the correlation between the jitter value and the asymmetry value. (Step S14). From the parameters of the recording strategy for each recording mark length determined in step S14, the parameters of the recording strategy at the shortest mark length are obtained by calculation. Specifically, for example, when the data after recording modulation is (1, 7) RLL, the estimated interpolation is used from the leading pulse width 4Ttop of the 4T mark length determined in step S14 and the leading pulse width 3Ttop of the 3T mark length. Thus, the head pulse width 2Ttop having the shortest mark length 2T is calculated. As the estimation interpolation, for example, the following equation can be used.
2Ttop = 2 × 3Ttop-4Ttop

  In this embodiment, each parameter of the recording strategy of the recording mark that is 1T longer than the shortest mark length included in the predetermined recording pattern, and each of the recording strategy of the recording mark that is longer than the shortest mark length by 2T or more and below the longest mark. Each parameter of the recording strategy with the shortest mark length is set using the parameters. For this reason, even when the playback signal jitter is large and the recording strategy parameters cannot be set from the playback signal with the shortest mark length, the recording strategy parameters for recording the recording mark with the shortest mark length satisfactorily. It can be set easily.

Example 1
As an example, an experiment was performed using an optical disc apparatus equipped with an optical head having a numerical aperture NA of 0.85 and a laser wavelength of λ405 nm. In the experiment, on a phase change optical disk with a cover layer thickness of 0.1 mm, the linear velocity is 5 m / s, the shortest mark 2T length in (1,7) RLL is 0.13 μm (the shortest bit length is 0.104 μm / bit). The recording conditions when recording was set according to the procedure shown in FIG. The (n-1) T pulse train shown in FIG. 17B is used as the laser drive waveform when forming the recording mark on the optical disk. In the optical disc apparatus, parameters other than the recording power Pw, the leading width Ttop, and the trailing edge cooling width Tcl are set to the specified values read from the optical disc itself in step S11 (FIG. 1).

  FIG. 2 shows an example of a combination of changes in recording conditions. In step S12 (FIG. 1), for example, the recording power Pw is changed in 5% steps in the range of −10 to +10 (%), for example, with the value read in step S11 as the center. Further, the head width Ttop and the rear end cooling width Tcl are each in the range of −0.15 to +0.15 (T), for example, 0.05T step with the specified value read in step S11 as the center. Change. For example, when the head pulse width Top read in step S11 is 1T, the head pulse width Top is changed in the range of 0.85T to 1.15T, and when the head width Ttop is 0.5T, The pulse width Top is changed in the range of 0.35T to 0.65T.

  In the experiment, in step S12, the recording power Pw was changed in the range indicated by the shaded portion in FIG. 2 (25 patterns) for each of the changed leading width Ttop and trailing edge cooling width Tcl. The leading width Ttop and the trailing edge cooling width Tcl are a combination of changing the trailing edge cooling width Tcl by fixing the leading width Ttop, or conversely, a combination of changing the leading width Ttop by fixing the trailing edge cooling width Tcl. It was decided to climb as appropriate and changed.

  In step S12, recording is performed on the optical calibration area (PCA) of the optical disc by changing each mark from the shortest mark (2T) to the longest mark (8T) in the combination shown in FIG. 2 in units of 2048 bytes / sector. It was. In step S12, first, the recording power in each head width Ttop and rear end cooling width Tcl was selected. In selecting the recording power, an 8T mark and a space having a large signal amplitude and suitable as an adjustment target were used. Specifically, a technique of selecting a laser power as a recording power, which has been used in the past and whose 8T mark and space size are closest to the theoretical values, was employed.

  Next, in step S13, the recorded recording mark is reproduced, an asymmetry value is calculated for each recording condition for each recording mark length excluding the shortest mark (2T), and recording can be performed satisfactorily based on the asymmetry value. Strategy parameters (Ttop, Tcl) were determined for each recording mark length. Since the value of the asymmetry value varies depending on the combination of the optical head and the type of the optical disk, it is preferable to estimate in advance the range in which it is determined that the recording can be satisfactorily performed according to the configuration of the optical head. Further, when there is an encouragement value for each optical disc, the determination may be made based on the encouragement value. It should be noted that the same value can be commonly used for the recording mark as the leading width Ttop and the trailing edge cooling width Tcl when recording the 4T mark to the 8T mark. Therefore, in this embodiment, parameters of a recording strategy that can be recorded satisfactorily for the 4T mark are obtained, and the same parameters as the 4T mark are adopted for the 5T mark to the 8T mark.

In step S15, the estimated interpolation is performed from the relationship between the recording strategy parameter (3Ttop, 3Tcl) of 3T mark 1T larger than the shortest mark 2T and the recording strategy parameter (4Ttop, 4Tcl) of 2T larger than the shortest mark 2T by 2T. Thus, the parameters (2Ttop, 2Tcl) of the recording strategy at the shortest mark 2T were obtained. Linear interpolation is used for the estimation interpolation, and the difference between the parameters at the 3T mark and the 4T mark is subtracted from the parameter at the 3T mark,
2Ttop = 2 × (3Ttop) − (4Ttop)
2Tcl = 2 × (3Tcl) − (4Tcl)
Sought by.

  As for the reproduction signal of the signal recorded in step S12, the amplitude ratio when reproducing the shortest recording mark 2T and the longest recording mark 8T in the data after the recording modulation limited in run length is 10% or less. The jitter at each recording mark has a large variance, and the jitter between the clock and data exceeds 15%, and it is impossible to measure the performance using the reproduced signal.

  3 and 4 show the relationship between the recording strategy parameter and the mark length obtained in the above embodiment. In FIG. 3, the vertical axis represents the leading width Ttop, and the horizontal axis represents the recording mark length. The leading width Ttop of the 2T mark length is obtained from the relationship between the leading widths Ttop of both the 3T mark length and the 4T mark length (4T mark length or more). In FIG. 4, the vertical axis represents the rear end cooling width Tcl, and the horizontal axis represents the recording mark length. The rear end cooling width Tcl of the 2T mark length is obtained from the relationship between the rear end cooling width Tcl of both the 3T mark length and the 4T mark length (4T mark length or more). In FIGS. 3 and 4, the parameters for the recording power of −10% to + 5% are plotted with the recording power determined in step S14 (FIG. 1) as the center (◇). As shown in FIGS. 3 and 4, the head width Ttop at each recording mark length becomes shorter (smaller) as the recording power increases.

Next, in order to verify whether or not the recording conditions determined according to the procedure shown in FIG. 1 are appropriate, verification was performed by PRML detection. When recording was performed under the recording conditions determined as described above, it was confirmed that the bit error rate (hereinafter referred to as BER) in PRML detection was 10 ⁻⁴ or less of the target. For reference, the parameters (Ttop, Tcl) for the recording power of −10% to + 5% with the recording power determined in step S14 as the center are obtained and the bit error rate is verified. Even when recording was performed under the conditions, the BER was 10 ⁻⁴ or less. That is, a recording power of −10% to + 5% indicates a margin with respect to the central recording power.

  As described above in the embodiment, by setting the recording strategy parameters of the 2T mark from the recording strategy of the 3T mark and the 4T mark or more, the recording density at which the jitter or asymmetry value cannot be obtained using the reproduction signal. Also in the case where the 2T mark is formed, it was confirmed that the parameters of the recording strategy used for forming the 2T mark can be set easily and with high accuracy.

  FIG. 5 shows an outline of the procedure of the recording condition setting method according to the second embodiment of the present invention. In this embodiment, by changing the linear velocity and the channel clock period, the recording density is lowered to such an extent that the jitter and asymmetry values can be calculated using the reproduction signal for the shortest mark, and each recording strategy is determined by the recording density. A parameter is obtained, and each parameter of the recording strategy when the recording density is set high is determined based on the parameter.

  As shown in FIG. 5, first, similarly to step S11 shown in FIG. 1, parameters of the recording power and the recording strategy are read and set as specified values (step S21). When each parameter of recording power and recording strategy corresponding to a plurality of recording conditions (recording density) is stored (recorded) on the optical disc apparatus or optical disc, each parameter of recording power and recording strategy corresponding to the recording conditions Is read out.

  Next, a predetermined recording pattern including each recording mark length in the modulation rule is recorded on the optical disc by changing the recording power and the recording strategy, changing the recording conditions and changing the recording density (step S22). At this time, when the recording mark formed on the optical disc is reproduced, the recording in which the ratio of the reproduction signal having the longest mark length to the reproduction signal having the shortest mark length is 10% or less is performed. The density is set to a recording density at which the amplitude ratio becomes larger than 10% by relaxing the recording conditions. In step S2, if the shortest mark length at the original recording density is Lmin, for example, for each recording density where the shortest mark (test mark) length is Lp2, Lp1, Lp0 (Lp2> Lp1> Lp0> Lmin), the recording power And change each parameter of the recording strategy.

  The data recorded in step S22 is reproduced, and the jitter value or β value is calculated based on the reproduced signal (step S23). At the original recording density, since the reproduction amplitude ratio between the longest mark and the shortest mark is 10% or less, the jitter value and β value of the shortest mark cannot be calculated from the reproduction signal, but the recording density is lowered. Therefore, the jitter value and β value can be calculated by directly using the reproduction signal. Based on the jitter value or β value calculated in step S23, each parameter of recording power and recording strategy capable of satisfactorily reproducing the recording signal at each recording mark length is obtained for each recording density (step S24).

  Based on the recording strategy parameters obtained at a recording density lower than the original recording density, the recording strategy parameters for recording at the original recording density are determined (step S25). For example, when recording is performed at three recording densities such that the shortest mark length is Lp2, Lp1, Lp0 (Lp2> Lp1> Lp0> Lmin), the parameters of the three recording strategies for each recording mark length are used. Then, the estimated interpolation is performed to determine the parameter value at each recording mark length at the original recording density where the shortest mark length is Lmin. For example, as the estimated interpolation, an approximation of the second order can be used for the shortest recording mark length and the recording mark length longer by one channel clock period than the shortest recording mark length, and the primary order is used for recording marks longer than these. An approximation can be used.

  In the present embodiment, the recording density is reduced to calculate the jitter value and β value of the reproduction signal, and the recording strategy parameter at the original high recording density is estimated by estimation interpolation from the recording strategy parameter obtained based thereon. Is determined. The parameter setting in a state where the recording density is low can be performed by a method similar to the conventional method and does not require a new device. For this reason, even in the case of performing high density recording in which the jitter value and β value cannot be calculated by directly using the reproduction signal, it is possible to easily determine the recording strategy parameter capable of good recording.

Example 2
As an example, an experiment was performed using an optical disc apparatus equipped with an optical head having a numerical aperture NA of 0.65 and a laser wavelength of λ405 nm. In the experiment, FIG. 5 shows recording conditions when recording is performed on a phase change optical disk having a cover layer thickness of 0.6 mm and the shortest mark 2T length (Lmin) in (1, 7) RLL is set to 0.125 μm. Set according to the procedure shown. When the shortest mark 2T length is set to 0.125 μm, the ratio between the reproduction signal of the longest mark and the reproduction signal of the shortest mark is 10% or less, and the reproduction signal including the reproduction signal of the shortest mark The jitter exceeded 15%, and it was impossible to determine the recording strategy parameters and the like by directly using the reproduction signal.

  In the experiment, the (n-1) T pulse train shown in FIG. 17B was used as the laser drive waveform when forming the recording mark on the optical disc. In the optical disc apparatus, parameters other than the recording power Pw, the leading width Ttop, and the trailing end cooling width Tcl are set to the specified values read from the optical disc apparatus in step S21 (FIG. 5) or read from the optical disc itself. .

  In step S22, a predetermined recording pattern constituted by each mark from the shortest mark (2T) to the longest mark (8T) in units of 2048 bytes / sector in the PCA (power calibration area) of the optical disk is combined as shown in FIG. Recording was performed while changing the recording density while changing the same combination. At this time, the recording density was changed by reducing the channel clock while keeping the linear velocity constant. Specifically, the recording density at which the shortest mark length was Lmin = 0.125 was lowered to the recording density at which Lp2 = 0.17 μm, Lp1 = 0.16 μm, and Lp0 = 0.15 μm. At this time, at a recording density where the shortest mark length is Lp0 or more, the ratio of the reproduction signal with the longest mark length to the reproduction signal with the shortest mark length exceeds 10%, and the reproduction signal has a jitter value of 15%. It became less than.

  In step S24, first, the recording power was selected in the same procedure as in step S14 in the first embodiment. Next, the recorded recording mark is reproduced, an asymmetry value is calculated for each recording condition, and a recording strategy parameter (Ttop, Tcl) that can be recorded satisfactorily based on the asymmetry value is recorded for each recording density. We asked for each length.

  FIG. 6 shows the relationship between the recording strategy parameter and the recording density (shortest mark length) obtained in the above embodiment. In step S25, parameters of the recording strategy at the original recording density (shortest mark length Lmin) are obtained by quadratic approximation from the relationship of the recording strategy parameters (● in graph (a)) at the shortest mark 2T at each recording density. (A) ○) was determined. Similarly, from the relationship of the recording strategy parameters (● in graph (b)) at the 3T mark at each recording density, the recording strategy parameters (graph (b)) at the original recording density (shortest mark length Lmin) are obtained by quadratic approximation. )) Is determined, and from the relationship of the recording strategy parameter (● in graph (c)) at the 4T mark at each recording density, the recording strategy at the original recording density (shortest mark length Lmin) is obtained by first-order approximation. The parameters (O in graph (b)) were determined.

Next, in order to verify whether or not the recording conditions determined according to the procedure shown in FIG. 5 are appropriate, verification was performed by PRML detection. When recording was performed under the recording conditions determined as described above, it was confirmed that the bit error rate (hereinafter referred to as BER) in PRML detection was 10 ⁻⁴ or less of the target.

  As described above, as shown in the embodiment, each parameter of the recording strategy when the recording density is low is obtained for a plurality of recording densities, and from the relationship of each parameter in the plurality of recording densities, when the recording density is high by estimated interpolation By calculating the parameters, it was confirmed that each parameter of the recording strategy can be easily set even for the recording density in which the jitter and asymmetry values cannot be calculated using the reproduction signal.

  FIG. 7 shows an outline of the procedure of the recording condition setting method according to the third embodiment of the present invention. First, as in step S21 shown in FIG. 5, the recording power and recording strategy parameters are read and set as specified values (step S31). Next, a predetermined recording pattern including each recording mark length in the modulation rule is recorded on the optical disc with a plurality of recording densities while changing each parameter of the recording power and the recording strategy (step S32). At this time, the ratio between the reproduction signal amplitude of the longest mark and the reproduction signal amplitude of the shortest mark is set to 10% or more for any recording density of the plurality. In step S32, for example, a predetermined recording pattern is recorded in units of 2040 bytes / sector at recording densities at which the shortest mark length is Lp2, Lp1, and Lp0 (Lp2> Lp1> Lp0).

  The data recorded in step S32 is reproduced, and the performance of the reproduction signal is measured based on the data (step S33). In the performance measurement, for example, a bit error rate using PRML detection can be used. Based on the measured performance, a range of recording conditions for each recording mark length satisfying a predetermined performance index is derived (step S34).

FIG. 8 shows, for each recording mark length, a range in which the error bit rate is 10 ⁻⁴ or less when the leading width Ttop is changed. In step S34, for each recording mark length, for example, a range in which the bit error rate BER indicated by hatching in the drawing is 10 ⁻⁴ or less is obtained from the boundary of whether or not predetermined performance at each recording density is satisfied.

  Using the range obtained in step S34, the ratio between the amplitude of the reproduction signal with the maximum mark length and the amplitude of the reproduction signal with the shortest mark length is 10% or less, that is, the recording whose performance cannot be obtained directly from the reproduction signal. Determine the recording conditions in terms of density. For example, when the leading width 2Ttop at the shortest mark 2T when the recording density is increased is determined from the range shown in FIG. 8, it becomes a boundary of a range satisfying predetermined performance in each of Lp2, Lp1, and Lp0. A plurality of relational expressions may be obtained by approximation using parameter values, and a recording parameter of 2 Ttop may be determined using the obtained relational expressions.

  In this embodiment, since the approximation is performed with a plurality of relational expressions based on the boundary of the range satisfying the predetermined performance, the recording condition is high even when the recording density is high and the jitter of the reproduction signal exceeds 15%. In the setting, parameters defined by a plurality of relational expressions can be selected from a range satisfying a predetermined performance. The plurality of relational expressions may be configured to use a plurality of values within the range as well as the boundary of the range satisfying the predetermined performance.

  FIG. 9 shows the configuration of an optical disc apparatus that employs the recording condition setting method of the present invention. The optical disk device 10 includes an optical head 2 having a laser (LD), an LD driver 3, a determination circuit 4, a strategy selection circuit 5, and a strategy setting circuit 6. The optical head 2 irradiates the optical disk 1 with laser light and reads / writes the optical disk. The LD driver 3 drives the laser in the optical head 2 with the recording strategy set by the strategy setting circuit 6. The determination circuit 4 determines whether or not the recording conditions used for recording on the optical disc 1 are good. The strategy selection circuit 5 instructs the strategy setting circuit 6 on a recording strategy to be used for recording on the optical disc 1 based on the determination result of the determination circuit 4.

  In the optical disc apparatus 10, when data is recorded, a signal from a format controller (not shown) is supplied to a data modulation circuit (not shown) to modulate the data. The strategy setting circuit 6 drives the laser in the optical head 2 via the LD tribar 3 with a strategy set so as to improve recording and reproduction, and the modulated data is recorded on the optical disc 1. When setting a recording strategy, a reproduction signal from the optical disc 1 is supplied to a determination circuit 4 through a reproduction amplifier (not shown), and the determination circuit 4 determines whether or not recording can be performed satisfactorily. Based on the determination result of the determination circuit 4, the strategy selection circuit 5 executes a strategy selection operation.

  FIG. 10 shows a detailed configuration of the strategy selection circuit 5. The strategy selection circuit 5 includes a recording condition derivation circuit 51, a control variable setting / storage circuit 52, a high density recording condition setting circuit 53, and a recording condition setting circuit 54. The storage condition derivation circuit 51 sets recording conditions according to the procedure shown in the above embodiment. Based on the determination of the determination circuit 4, the control variable setting / storage circuit 52 selects, stores, and sets strategy control variables that can be recorded satisfactorily. The high-density recording condition setting circuit 53 sets the recording strategy of the recording mark, which has a high recording density and cannot directly set the parameters of the recording strategy by directly using the reproduction signal, using estimated interpolation. The recording condition setting circuit 54 sets a recording strategy for recording marks that can set each parameter of the recording strategy using the reproduction signal.

  It should be noted that the predetermined recording pattern recorded on the optical disc in the above embodiment does not need to include all the constituent marks. For a recording mark that is longer than the shortest recording mark by 2T or more, any one of the recording marks is set to 1 It is sufficient to include the above. Further, the combination of changes in the parameters of the recording power and the recording strategy may be a combination other than that shown in FIG. 2, and the range of combinations and changes can be arbitrarily set.

  Hereinafter, an embodiment in which recording conditions are set by a microcomputer or the like mounted on an optical disc apparatus will be described. Here, an example in which the head width Ttop is selected from the parameters of the recording strategy will be described. In addition, since each parameter of the recording strategy for the 4T mark or more (≧ 4T mark) can be the same value as the parameter of the 4T mark, each parameter of the ≧ 4T mark will be described as each parameter of the 4T mark. .

  FIG. 11 is a flowchart showing a processing procedure of a program for selecting a recording condition by a procedure similar to the procedure shown in the flowchart shown in FIG. In the optical disc apparatus, the leading width Ttop is set under the control of a controller that implements functions corresponding to the determination circuit 4, the strategy selection circuit 5, and the strategy setting circuit 6 of FIG. The controller moves the optical head on which the laser or the like is mounted to the PCA area of the optical disc, and reads the prescribed value of the recording condition from the optical disc device or from the optical disc (step S41). Based on the read specified value, the controller creates a recording condition table used when recording a predetermined recording pattern including at least the 3T mark and the 4T mark under a plurality of recording conditions (step S42).

  12A and 12B show examples of the recording condition table created in step S42, respectively. In the figure, the initial value “× 1” of the relative power means the recording power of the specified value × 1 read in step S41. Further, in the table, the unit of the value of items other than the relative power is the channel clock T, and “-” in the table means that the same value as that of the column above that column is used. In step S42, for example, a recording condition table is created in which the specified value read in step S41 is set as an initial value, and the value of the parameter to be selected is varied within a predetermined range.

  In step S42, for example, as shown in FIG. 12A, the leading width 3Ttop of the 3T mark is within a range of ± 0.1T from the initial value (0.5T), that is, within a range of 0.4T to 0.6T. Thus, a recording condition table having five recording conditions from conditions 11 to 15 is created, which varies in increments of 0.05T and uses the same value as the initial value as other parameters. Further, as shown in FIG. 4B, the leading width 4Ttop of the 4T mark (4T mark or more) is in the range of ± 0.1T from the initial value (0.6T), that is, 0.5T to 0.7T. A recording condition table having five recording conditions from conditions 21 to 25 is generated, which varies in increments of 0.05T within the range and uses the same value as the initial value as other parameters.

  Returning to FIG. 11, the controller refers to the recording condition table created in step S42, and records a predetermined recording pattern on the optical disc while changing the recording condition (step S43). When the recording condition table shown in FIGS. 12A and 12B is created in step S42, in step S43, each of the conditions 11 to 15 in the table of FIG. The predetermined recording pattern is recorded under 25 (5 × 5) recording conditions in which the conditions 21 to 25 in the table of FIG. In step S43, for example, first, a predetermined recording pattern is recorded under five recording conditions in which the condition 11 and each of the conditions 21 to 25 are combined, and then the conditions 21 to 25 are sequentially set for the conditions 12 to 15. A predetermined recording pattern is recorded under five recording conditions each in combination.

  The controller reproduces a predetermined recording pattern recorded on the optical disc (step S44), and measures a β value or jitter σ when a mark other than the shortest mark included in the predetermined recording pattern is reproduced (step S45). The controller selects, as the selected recording condition, a recording condition that can best reproduce the predetermined recording pattern based on the absolute value of the measured β value or jitter σ for the marks other than the shortest mark (step S46). . In step S46, each parameter for recording the 3T mark and the recording mark of 4T mark or more is selected from the recording condition table shown in FIGS. 12A and 12B, for example.

  Subsequently, a parameter for recording the shortest mark is derived based on the parameter for recording a recording mark larger than the shortest mark obtained in step S46 (step S47). In step S47, as described in the first embodiment, the leading width 2Ttop of the shortest mark is derived based on the leading width 3Ttop of the 3T mark and the leading width 4Ttop of the 4T mark. The controller sets the recording conditions selected in step S46 and the parameters for recording the shortest mark derived in step S47 to the recording conditions used for data recording, and sets them in a predetermined area of the optical disc. The recorded recording conditions are recorded (step S48). By using a program that operates in such a procedure, as in the first embodiment, in the optical disc apparatus, it is possible to easily select recording conditions including parameters when recording the shortest mark.

  In the above embodiment, the recording power is fixed and the predetermined recording pattern is recorded. However, in step S42, a plurality of recording condition tables having different relative powers (FIG. 12) are created, A predetermined recording pattern may be recorded. At this time, as for the recording strategy parameter, when obtaining a parameter that can best reproduce the predetermined recording pattern for each recording power, as shown in FIG. Has a range of areas. In this case, in step S47, the center value of the area may be adopted as a parameter for recording a recording mark larger than the shortest mark, and a parameter for recording the shortest mark may be derived based on the parameter.

  FIG. 13 is a flowchart showing a processing procedure of a program obtained by changing a part of the program having the processing procedure shown in FIG. In this example, the controller records a predetermined recording pattern on the optical disc with some combination of the recording condition table, reads the recorded predetermined recording pattern, and measures the β value or jitter σ. In this example, when the measured β value or jitter σ does not satisfy the predetermined performance, the recording condition is changed to a combination of recording conditions different from the combination that has already been used. Until the performance is satisfied or until a predetermined recording pattern is recorded with all combinations of the recording condition table, a method of recording the predetermined recording pattern on the optical disc while changing the recording condition and deriving the parameter of the shortest mark is adopted. .

  Similar to the procedure shown in FIG. 11, the controller reads the specified value of the recording condition in step S41, and creates a recording condition table in step S42. In step S43, the controller records a predetermined recording pattern on the optical disc using only a part of the recording condition combinations in the recording condition table created in step S42. For example, when the recording condition table created in step S42 is as shown in FIG. 12, the controller sets the three recording conditions of conditions 11 to 13 (FIG. 12A) out of a total of 25 combinations. Then, a predetermined recording pattern is recorded on the optical disc using a total of nine combinations of recording conditions, which is a combination of the three recording conditions of conditions 21 to 23 ((b) in FIG. 5).

  The controller reproduces the recorded predetermined recording pattern in step S44, and measures the β value or jitter σ of the reproduction signal in step S45. The controller determines whether or not the β value (β0) or jitter (σ0) under the recording conditions in which the reproduction of the predetermined recording pattern can be best performed among the measured β value or jitter σ satisfies the predetermined performance. Judgment is made (step S51). In other words, the controller performs the performance of the reproduction signal when recording is performed using the recording conditions that can best reproduce the predetermined recording pattern among the recording conditions used for recording in step S43. Determine whether or not. When the β0 value or σ0 satisfies the predetermined performance, the controller proceeds to step S47, derives a parameter for recording the shortest recording mark, and sets the recording condition in step S48.

  When the controller determines in step S51 that β0 or σ0 does not satisfy the predetermined performance, the controller stores the value of β0 or σ0 and the recording condition corresponding to β0 or σ0 in the temporary storage device. The recording condition used when recording the predetermined recording pattern in step S43 of the loop is set to a combination that has not been used yet among the combinations of the recording condition table created in step S42 (step S52), and then proceeds to step S43. Returning, step S43 to step S51 are repeatedly executed. In step S52, the recording conditions used when the predetermined recording pattern is recorded in step S43 of the next loop are, for example, conditions 11 to 15 (FIG. 12A) and conditions 24 and 25 (FIG. 12B). Are set to 10 combinations.

  In step S43, the controller records a predetermined recording pattern again using the plurality of recording conditions set in step S52, and measures the β value or jitter σ of the reproduced signal. In step S51, the controller determines whether or not β0 or σ0 in the current loop satisfies a predetermined performance. When the controller determines that β0 or σ0 in the current loop satisfies the predetermined performance, the controller proceeds to step S47 and derives a parameter for recording the shortest mark.

  If it is determined in step S51 that β0 or σ0 of the current loop does not satisfy the predetermined performance, the controller compares β0 or σ0 in the previous loop with β0 or σ0 in the current loop, The β0 or σ0 that can reproduce the recorded pattern is memorized, and the process proceeds to step 52 again, and the recording conditions used when recording the predetermined recording pattern in step S43 of the next loop are not yet used. Set to combination. The controller determines whether or not β0 or σ0 satisfies the predetermined performance in step S51 or until there is no combination of recording conditions to be set in step S52, that is, the predetermined recording pattern for all combinations of the recording condition table. Step S43 to Step S51 are repeatedly executed until.

  In the example of FIG. 13, since the recording condition satisfying the predetermined performance can be found before recording the predetermined recording pattern using all combinations of the recording condition table, compared to the example shown in FIG. The time required for setting the recording conditions can be shortened. In addition, since the number of predetermined recording patterns to be recorded on the optical disc for setting the recording conditions can be reduced, it is not necessary to increase the area for recording the predetermined recording patterns on the recording medium.

  In the example of FIG. 13, in step S42, the recording condition table shown in FIGS. 12A and 12B is different from the recording condition table shown in FIGS. 12A and 12B only in relative power. When it is created, in step S43 of the first loop, a predetermined recording pattern is recorded under the recording conditions of combinations (25 types) of the recording condition tables shown in FIGS. In step S43 of this loop, it is also possible to record a predetermined recording pattern under recording conditions of combinations (25 ways) of recording condition tables that differ only in relative power from FIGS. In this case, selection of the leading width Ttop and selection of recording power can be performed simultaneously.

  FIG. 14 is a flowchart showing a processing procedure of a program for selecting a recording condition by the same procedure as that shown in the flowchart shown in FIG. The controller moves the optical head to the PCA area of the optical disk, and reads the specified value of the recording condition from the optical disk device or from the optical disk (step S61). When recording conditions corresponding to a plurality of recording densities are stored in the optical disk device or the optical disk, a configuration in which a prescribed value of the recording conditions is read for each recording density can be employed in step S61.

  The controller sets a plurality of recording densities used when recording a predetermined recording pattern including at least a 2T mark, a 3T mark, and a 4T mark on the optical disc (step S62). The recording density set here is lower than the original recording density, and for any recording density, the β value or the jitter σ can be satisfactorily measured from the reproduction signal of the 2T mark. In step S62, for example, the recording density at which the 2T mark length is Lp2, Lp1, Lp0 (Lp2> Lp1> Lp0> Lmin) is set with the 2T mark length at the recording density originally used for recording being Lmin.

  Based on the read specified value, the controller creates a recording condition table to be used when recording a predetermined recording pattern on the optical disc under a plurality of recording conditions (step S63). FIGS. 15A, 15B, and 15C show examples of the recording condition table created in step S63, respectively. In step S63, for example, the specified value read in step S61 is set as an initial value corresponding to each of the plurality of recording densities set in step S62, and the value of the parameter to be selected is changed within a predetermined range. A recording condition table is created.

In step S63, for each of the plurality of recording densities, for example, as shown in FIG. 15A, the leading width 2Ttop of the 2T mark is within a range of ± 0.1T from the initial value ( 0.6T ), that is, 0. A recording condition table having five recording conditions from conditions 31 to 35, in which the same value as the initial value is used as other parameters, varying in increments of 0.05T within a range of 5T to 0.7T. Is done. Further, the 3T mark leading width 3Ttop as shown in FIG. 6B fluctuates in increments of 0.05T within a range of ± 0.1T from the initial value ( 0.6T ), and other parameters are A recording condition table having five recording conditions from condition 41 to 45, in which the same value as the value is used, is created, and the leading width 4Ttop of the 4T mark (4T mark or more) as shown in FIG. Fluctuates in increments of 0.05T within the range of ± 0.1T from the initial value (0.6T), and the same values as the initial values are used as other parameters. A recording condition table having recording conditions is created.

  The controller refers to the recording condition table created in step S63, and records a predetermined recording pattern on the optical disc while changing the recording condition for each of the plurality of recording densities set in step S62 (step S64). When the recording condition tables shown in FIGS. 15A, 15B, and 15C are created in step S63, in step S64, the conditions in the table of FIG. 5 × 5 × 5 = 125 in which each of 31 to 35, each of the conditions 41 to 45 in the table of FIG. 15B, and each of the conditions 51 to 55 in the table of FIG. A predetermined recording pattern is recorded under the same recording conditions.

  In step S64, for example, in step S62, when three recording densities with the 2T mark length of Lp2, Lp1, and Lp0 are set, first, for the recording density with the 2T mark length of Lp2, the predetermined recording pattern is Are recorded under the 125 recording conditions. Next, for a recording density at which the 2T mark length is Lp1, a predetermined recording pattern is recorded under the 125 recording conditions described above, and for a recording density at which the 2T mark length is Lp0, the predetermined recording pattern is the above 125 patterns. Recorded under recording conditions. In this case, 125 × 3 predetermined recording patterns are recorded on the optical disc.

  The controller reproduces the predetermined recording pattern recorded on the optical disc (step S65), and measures the β value or jitter σ of the reproduced predetermined recording pattern for each recording density (step S66). Based on the measured β value or jitter σ, the controller selects, as the selected recording condition, a recording condition that can best reproduce the predetermined recording pattern for each recording density (step S67). In step S67, for example, the top width 2Ttop (2) of the 2T mark and the top width 3top (2) of the 3T mark and the top width 4Ttop (2) of the 4T mark at the recording density at which the 2T mark length is Lp2, are selected. The 2T mark start width 2Ttop (1) and the 3T mark start width 3top (1) and the 4T mark start width 4Ttop (1) are selected at a recording density at which the 2T mark length is Lp1, and the 2T mark length is Lp0. The leading width 2Ttop (0) of the 2T mark and the leading width 3top (0) of the 3T mark and the leading width 4Ttop (0) of the 4T mark are selected at the recording density.

  Subsequently, each parameter at the original recording density that is higher than the recording density used for recording the predetermined recording pattern at step S64 is a plurality of parameters whose density is lower than the original recording density obtained at step S66. Derivation is performed based on the parameter in the recording density (step S68). In step S68, as described in the second embodiment, the leading width 4Ttop of the 4T mark at the original recording density is 4Ttop (2), 4Ttop (1), and 4Ttop (1) obtained in step S67. 0) is derived by estimated interpolation. Similarly, the leading width 3Ttop of the 3T mark at the original recording density is derived from 3Ttop (2), 3Ttop (1), and 3Ttop (0), and 2Ttop (2), 2Ttop (1), and 2Ttop ( 0), the leading width 2Ttop of the 2T mark at the original recording density is derived.

  The controller sets the recording condition derived in step S68 as a recording condition used for data recording, and records the set recording condition in a predetermined area of the optical disc (step S69). By using a program that operates in such a procedure, as in the second embodiment, in the optical disc apparatus, the recording conditions including each parameter for recording the shortest mark at the original high recording density can be simplified. Can be selected. Also in this example, similarly to the example of FIG. 11, a plurality of recording condition tables having different relative powers (FIG. 12) may be created, and a predetermined recording pattern may be recorded with a plurality of recording powers. In this case, when the parameters for the recording strategy are determined so that the predetermined recording pattern can be reproduced most favorably for each recording power, the parameters that allow the predetermined recording pattern to be reproduced most favorably as shown in FIG. Will now have a range of areas. In this case, in step S68, the center value of the area may be adopted as a representative value, and parameters at the original recording density may be derived.

  FIG. 16 is a flowchart showing a processing procedure example of a program obtained by changing a part of the program having the processing procedure shown in FIG. In this example, as in the example of FIG. 13, the controller records a predetermined recording pattern on the optical disc with a partial combination of the recording condition table, reads the recorded predetermined recording pattern, and measures the β value or jitter σ. The In this example, when the measured β value or jitter σ does not satisfy the predetermined performance, the recording condition is changed to a combination of recording conditions different from the combination that has already been used. Until the performance is satisfied or until a predetermined recording pattern is recorded with all combinations of the recording condition table, the predetermined recording pattern is recorded on the optical disc while changing the recording condition, and the parameter at the original recording density is derived. Adopted.

  Similarly to the procedure shown in FIG. 14, the controller reads the specified value of the recording condition in step S61, sets a plurality of recording densities in step S62, and creates a recording condition table in step S63. In step S64, the controller records a predetermined recording pattern on the optical disc at one of the plurality of recording densities set in step S62. At that time, the controller uses only a part of the combination of the recording conditions in the recording condition table created in step S63. For example, when the recording condition table created in step S63 is as shown in FIG. 15, the controller records the three recording conditions of conditions 31 to 13 (FIG. 15A) and conditions 41 to 43 (same as above). The predetermined recording pattern is recorded on the optical disc under a total of 27 combinations of recording conditions in which the three recording conditions in FIG. (B)) and the three recording conditions 51 to 53 (FIG. (C)) are combined. To record.

  In step S65, the controller reproduces the recorded predetermined recording pattern, and in step S66, measures the β value or jitter σ of the reproduction signal. The controller determines whether or not the β value (β0) or the jitter σ (σ0) under the recording conditions in which the reproduction of the predetermined recording pattern can be best performed among the measured β value or jitter σ satisfies the predetermined performance. Is determined (step S71). In other words, the controller performs the performance of the reproduction signal when recording is performed using the recording conditions that can best reproduce the predetermined recording pattern among the recording conditions used for recording in step S64. Determine whether or not. When it is determined that the β0 value or σ0 does not satisfy the predetermined performance, the controller stores the value of β0 or σ0 and the recording condition corresponding to β0 or σ0 in the temporary storage device as in step S52 of FIG. Then, the recording condition used when recording the predetermined recording pattern in step S64 of the next loop is set to a combination that has not been used yet among the combinations of the recording condition table created in step S63 (step S72). Returning to Step S64, Steps S64 to S71 are repeatedly executed.

  In step S72, the recording conditions used when recording the predetermined recording pattern in step S64 of the next loop are, for example, conditions 31 to 35 (FIG. 15A) and conditions 44 and 45 (FIG. 15B). , Conditions 54 and 55 (FIG. 5C) are set to 20 combinations. In step S64, the controller records a predetermined recording pattern again using the plurality of recording conditions set in step S72, and again measures the β value or jitter σ value of the reproduced signal. In step S71, the controller determines whether or not β0 or σ0 in the current loop satisfies a predetermined performance.

  When the controller determines that β0 or σ0 satisfies the predetermined performance, the controller determines whether or not there remains a recording density in which the predetermined recording pattern has not yet been recorded among the plurality of recording densities set in step S62 (step S62). S73). If the controller determines that there is a recording density that is not yet used for recording the predetermined recording pattern, the recording density is not used for recording the predetermined recording pattern among the plurality of recording densities set in step S62. The recording density is changed (step S74), the process returns to step S63, and steps S63 to S66 and steps S71 and S72 are repeatedly executed.

  If it is determined in step S73 that there is no recording density that is not used for recording the predetermined recording pattern, the process proceeds to step S68, and parameters at the original recording density are derived. In this way, the controller changes the recording condition and the recording density until the recording condition satisfying the predetermined performance of β0 or σ0 is obtained for all of the plurality of recording densities set in step S62. The process up to step S71 is repeated. In this example, as in the example of FIG. 13, the recording condition satisfying the predetermined performance can be found before the predetermined recording pattern is recorded using all combinations of the recording condition table. Compared to the example, the time required for setting the recording conditions can be shortened. In addition, since the number of predetermined recording patterns to be recorded on the optical disc for setting the recording conditions can be reduced, it is not necessary to increase the area for recording the predetermined recording patterns on the recording medium.

  In the above-described embodiments with reference to FIGS. 11 to 16, the example of setting the head width Ttop has been described. However, instead of or in addition to this, other parameters may be set. it can. For example, in FIG. 11, when there are a plurality of parameters to be selected, step S42 to step S47 may be repeated according to the number of parameters to be selected. Specifically, an example in which both the leading width Ttop and the trailing edge cooling width Tcl are set according to the procedure shown in FIG. In this case, first, in step S42 of the first loop, the specified values read in step S41 are used for parameters other than the head width Ttop, and a recording condition table in which the value fluctuates for the head width Ttop is created. Then, the leading width Ttop is selected. Next, in step S42 of the second loop, a value selected in the first loop is used for the leading width Ttop, and a recording condition table in which the value varies for the trailing end cooling width Tcl is created. The end cooling width Tcl is selected. By such a procedure, both the leading width Ttop and the trailing edge cooling width Tcl can be selected.

  Although the present invention has been described based on the preferred embodiment, the recording condition setting method, the information recording apparatus using the same, and the program are limited only to the above embodiment. Rather, various modifications and changes made from the configuration of the above embodiment are also included in the scope of the present invention.

6 is a flowchart showing the flow of processing in the recording condition setting method according to the first embodiment of the present invention. The table | surface which shows an example of the combination of the recording conditions changed by step S2 of FIG. The graph which shows the relationship between head width Ttop and recording mark length. The graph which shows the relationship between the rear end cooling width Tcl and the recording mark length. The flowchart which shows the flowchart of the process in the recording condition setting method of 2nd Embodiment of this invention. The graph which shows the relationship between the head width Ttop and the shortest mark length (recording density). 10 is a flowchart showing the flow of processing in a recording condition setting method according to a third embodiment of the present invention. The graph which shows the relationship between the head width Ttop and the shortest mark length (recording density). 1 is a block diagram showing a configuration of an information recording / reproducing apparatus according to an embodiment of the present invention. The block diagram which shows the detailed structure of the strategy selection circuit structure 5 of FIG. The flowchart which shows the process sequence of the program which selects a recording condition by the procedure similar to the procedure shown by the flowchart shown in FIG. (A) And (b) is a table | surface which shows the example of the recording condition table respectively produced by step S42. The flowchart which shows the process sequence of the program which changed a part of program which has the process sequence shown in FIG. 6 is a flowchart showing a processing procedure of a program for selecting a recording condition by a procedure similar to the procedure shown in the flowchart shown in FIG. (A), (b), and (c) are tables showing examples of the recording condition table created in step S63, respectively. The flowchart which shows the process sequence example of the program which changed a part of program which has the process sequence shown in FIG. The wave form diagram which shows an example of the general laser drive waveform used for recording mark formation. An example of a waveform of a signal used for a general asymmetry value (β value). (A) shows recording data, (b) is a waveform example showing the waveform of the reproduction signal. Reproduction eye pattern waveform example when the shortest bit length is changed. The plot figure which shows the relationship between the shortest mark length and the jitter of the reproduction signal.

Explanation of symbols

1: Optical disk medium 2: Optical head 3: LD driver 4: Determination circuit 5: Strategy selection circuit 6: Strategy setting circuit 10: Optical disk device 51: Recording condition derivation circuit 52: Control variable setting / storage circuit 53: High density recording condition Setting circuit 54: recording condition setting circuit

Claims (17)

A recording condition setting method for an information recording medium,
A plurality of reproduction signals obtained by recording a first test mark that is longer by one recording length unit than a shortest mark in a modulation code used for information recording under a plurality of recording conditions and reproducing the recorded first test mark Select the first recording condition based on
One or more second test marks selected from marks having a length two recording units longer than the shortest mark length and not longer than the longest mark are recorded under a plurality of recording conditions, and the recorded second test mark is recorded The second recording condition is selected based on a plurality of reproduction signals obtained by reproduction,
A recording condition setting method for an information recording medium, wherein the recording condition of the shortest mark is obtained based on the first and second recording conditions.   The recording condition setting method for an information recording medium according to claim 1, wherein the reproduction amplitude of the shortest mark is 10% or less of the reproduction amplitude of the longest mark.   3. The recording condition setting method for an information recording medium according to claim 1, wherein a jitter of a reproduction signal including the reproduction signal of the shortest mark is 15% or more.   4. The method according to claim 1, wherein the plurality of recording conditions are obtained by varying at least one of a laser power of a recording laser, a leading pulse width, an intermediate pulse width, a trailing edge pulse width, and a trailing edge cooling width. Recording condition setting method described in 1.   5. The recording condition setting method according to claim 1, wherein the first and second recording conditions are selected based on asymmetry or jitter of the reproduction signal. A recording condition setting method for an information recording medium,
Record a test mark including at least the shortest mark at a plurality of recording densities where the information recording density is lower than the recording density during normal recording,
Reproducing the recorded test mark, obtaining a recording condition for obtaining a good reproduction signal based on the absolute value of asymmetry or jitter at each of the plurality of recording densities,
A recording condition setting method characterized in that a recording condition of at least the shortest mark recorded at the recording density at the time of normal recording is obtained based on the plurality of recording densities and the recording condition from which the good reproduction signal is obtained. .   The plurality of recording densities employ at least one of a channel clock having a longer period than a channel clock used for normal information recording and a linear velocity faster than the linear velocity of a recording medium used for normal information recording. The recording condition setting method according to claim 6, wherein the recording condition setting method is obtained.   At the recording density at the time of normal recording, the reproduction amplitude of the shortest mark is 10% or less of the reproduction amplitude of the longest mark. At a plurality of recording densities lower than the recording density at the time of normal recording, The recording condition setting method according to claim 6 or 7, wherein the reproduction amplitude is 10% or more of the reproduction amplitude of the longest mark.   The recording condition setting method according to claim 6, wherein the recording condition of the shortest mark is obtained by approximation of a quadratic function. The numerical aperture NA is 0.6 to 0.7, light source wavelength λ is 390nm or 410nm or less, the substrate thickness is 0.6mm disc to be recorded, the lower limit of the shortest mark length is 145 nm, claims 1-9 The recording condition setting method according to any one of the above. The numerical aperture NA is 0.7 to 0.85, the light source wavelength λ is 390nm or 410nm or less, the substrate thickness is 0.1mm disc to be recorded, the lower limit of the shortest mark length is 120 nm, claims 1 to 10, The recording condition setting method according to any one of the above. An information recording apparatus for optically recording information on an information recording medium,
Recording condition setting means for setting recording conditions when recording information on the information recording medium;
Adopting a plurality of recording conditions set by the recording condition setting means, a first test mark longer than the shortest mark in the modulation code used for information recording by one recording length unit, and two recording units from the shortest mark length A recording means for recording one or more second test marks selected from marks having a length greater than or equal to a length and less than or equal to the longest mark on an information recording medium;
Reproducing means for reproducing the first test mark and the second test mark from the information recording medium to generate a reproduction signal;
Signal processing means for selecting a first recording condition based on the reproduction signal of the first test mark and a second recording condition based on the reproduction signal of the second test mark, respectively .
The recording condition setting means, based on the first recording condition and the second recording condition is selected by the signal processing unit, the information recording apparatus characterized by setting the recording condition of the shortest mark. An information recording apparatus for optically recording information on an information recording medium,
A recording means for recording a test mark including at least the shortest mark at a plurality of recording densities in which the information recording density is lower than the recording density at the time of normal recording;
Reproducing means for reproducing a test mark recorded by the recording means to generate a reproduction signal;
In each of the plurality of recording densities, signal processing means for obtaining a recording condition for obtaining a good reproduction signal based on an absolute value of asymmetry or jitter from the reproduction signal;
Recording condition setting means for setting the recording conditions of at least the shortest mark to be recorded at the recording density at the time of normal recording based on the plurality of recording densities and the recording conditions from which the good reproduction signal was obtained. An information recording apparatus characterized by the above. A program for setting recording conditions for recording information on an information recording / reproducing medium,
Setting a plurality of test recording conditions based on initial recording conditions set in advance in the information recording medium or information recording / reproducing apparatus;
Under each set test recording condition, a recording mark (first test mark) that is longer by one recording length unit than the shortest mark in the modulation code used for information recording, and two recording units than the shortest mark Recording a signal using data including one or more recording marks (second test marks) selected from marks having a length greater than or equal to a length and less than or equal to the longest mark;
Replaying the recorded signal and detecting asymmetry or jitter of the regenerated reproduction signal;
Extracting one test recording condition for each of the first test mark and the second test mark based on an absolute value of asymmetry or jitter detected for each of the test recording conditions;
A program comprising: determining a recording condition for the shortest mark based on a test recording condition obtained for the first test mark and a test recording condition obtained for the second test mark. A program for setting recording conditions for recording information on an information recording / reproducing medium,
A first step of selecting a plurality of test recording conditions based on an initial recording condition or a modified recording condition preset in the information recording medium or information recording / reproducing apparatus;
Under the selected test recording conditions, a recording mark (first test mark) that is one recording length unit longer than the shortest mark in the modulation code used for information recording, and two recording unit lengths than the shortest mark A second step of recording a signal using data including one or more recording marks (second test marks) selected from marks having a length longer than or equal to or longer than the longest mark;
A third step of reproducing the recorded signal and detecting asymmetry or jitter of the reproduced signal;
Based on the absolute value of asymmetry or jitter detected for each of the test recording conditions, the quality of each test recording condition is determined, and the test recording condition determined to be good for either the first test mark or the second test mark. If there is no test recording condition, the process returns to the second step and the test recording condition is selected again. If there is a test recording condition determined to be good for both the first test mark and the second test mark, the process proceeds to the next step. When,
Fifth step of determining the recording condition for the shortest mark based on the test recording condition obtained for the first test mark determined as good and the test recording condition obtained for the second test mark determined as good. A program characterized by having the above sequentially. A program for setting recording conditions for recording information on an information recording / reproducing medium,
Setting the information recording density to a plurality of recording densities lower than the recording density during normal recording;
For each of the plurality of recording densities, selecting a plurality of test recording conditions based on an initial recording condition preset in the information recording medium or the information recording / reproducing apparatus;
For each of the plurality of recording densities, recording a signal including a mark having a predetermined recording unit length under the selected plurality of test recording conditions;
Replaying the recorded signal for each of the plurality of recording densities and detecting asymmetry or jitter of the regenerated reproduction signal;
Selecting one test recording condition for a mark having the predetermined recording unit length based on an absolute value of asymmetry or jitter detected for each of the test recording conditions for each of the plurality of recording densities;
Setting recording conditions for the mark having the predetermined recording unit length at the recording density at the time of normal recording based on the plurality of recording densities and the test recording conditions selected for each of the recording densities. A program characterized by having. A program for setting recording conditions for recording information on an information recording / reproducing medium,
A first step of setting the information recording density to one of a predetermined number of recording densities lower than the recording density during normal recording;
A second step of selecting a plurality of test recording conditions based on an initial recording condition or a modified recording condition preset in the information recording medium or information recording / reproducing apparatus;
A third step of recording a signal including a mark having a predetermined recording unit length under the plurality of selected test recording conditions;
A fourth step of reproducing the recorded signal and detecting asymmetry or jitter of the reproduced signal;
Whether or not each test recording condition is good is determined based on the absolute value of asymmetry or jitter detected for each of the test recording conditions, and when there is no test recording condition determined to be good, the process returns to the second step to return to the plurality of test recording conditions. The test recording conditions are selected again, and when there is a test recording condition determined to be good, and when all of the predetermined number of recording densities have not been selected, the process returns to the first step and another recording density is obtained. And when all of the predetermined number of recording densities have been selected, the fifth step moves to the next step;
A sixth step of setting recording conditions for the mark having the predetermined recording unit length at the recording density at the time of normal recording based on the plurality of recording densities and the recording conditions selected for each of the recording densities A program characterized by having the above sequentially.

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