Method for obtaining recording pulse condition of optical disk and its device

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention is an optical disc that reads out the recording pulse standard condition from a writable optical disc in which the recording pulse standard condition is pre-recorded in a specific area, sets the recording pulse condition of the recording / reproducing device, and records / reproduces data. It relates to a method and an apparatus for obtaining the recording pulse condition of.

【0002】

[Conventional technology]

The DVDRAM standard is an example of an optical disc that can rewrite a large amount of data, and a device that can record 2.6 GB of data by the mark edge recording method on one side of an optical disc with a diameter of 12 cm using a phase change recording film has already been put into practical use. ing. In order to put a higher-density optical disc into practical use, the inventors have described a disc recording method capable of reducing the deviation of the mark edge position due to thermal interference between marks, which is a problem in high-density recording of a phase-changing optical disc (reference: patent). No. 2679596) is being considered.

【0003】

In the disk recording method, when data is recorded as an amorphous mark on a disk at a mark edge, the laser beam is composed of a plurality of pulse trains called multi-pulses and recorded. In high-density recording, the mark size to be recorded and the distance between the spaces (between the marks) are small, so the heat of the laser beam applied to form the mark reaches not only the self-mark but also the front and rear marks through the space. , Self-mark and front and rear mark shapes are distorted. In order to avoid this, the start pulse position of the multi-pulse for forming the mark is set by the relationship between the self-mark length and the front space length, and the final pulse position of the multi-pulse for forming the mark is set by the self-mark. By changing the relationship between the length and the back space length, the amount of thermal interference between the marks is corrected in advance and recorded. This control of the recording pulse position is generally called recording compensation. The recording pulse condition (recording compensation parameter) has a different value for each combination of mark spaces, and is, for example, a table as shown in FIG. Figure 3 shows the positional relationship between the mark and space for each value in the table.

【0004】

In order to realize an actual optical disc recording / playback device, it is necessary to store the recording pulse conditions for performing recording compensation in the device or disk. In order to enable the use of a plurality of disks having different characteristics, that is, different recording pulse conditions, this value may be recorded in advance on the disk and read out by an apparatus when used.

【0005】

[Problems to be Solved by the Invention]

When mass-produced optical disc recording / playback devices, the individual devices do not always have the same characteristics due to variations in the characteristics of the parts used and changes in the environment. For example, in a laser driving means related to recording and a head equipped with a laser, the pulse width changes even if the same current waveform is supplied to the laser mainly due to variations in laser characteristics. It is not always possible to obtain the same emission waveform with individual devices. Similarly, the characteristics of the optical disc itself vary to some extent during mass production, and even if the same emission waveform is recorded, the same mark shape is not always obtained for each optical disc.

【0006】

Therefore, if a reference disk with standard characteristics is used and the recording pulse standard conditions determined by the reference device with standard characteristics are used as they are for mass-produced disks and devices with varying characteristics, it is appropriate depending on the combination. There was a problem that quality defects occurred because the recording and reproduction were not performed properly.

【0007】

Furthermore, there are few problems if the disc is manufactured under sufficient quality control and has small variation in characteristics, but if the recording pulse standard conditions pre-recorded on the disc deviate significantly from the disc performance, the device Even if the recording pulse standard conditions read from the disc are faithfully reproduced, there is a problem that the characteristics cannot be exhibited with this disc.

【0008】

The present invention solves the above-mentioned problems, and reads the recording pulse standard condition from a writable optical disc in which the recording pulse standard condition is pre-recorded in a specific area, and sets the recording pulse condition of the recording / playback device. In the method of setting the recording condition of an optical disc for setting and recording / reproducing data, the first aspect is to provide a method of setting a recording condition of a writable optical disc and an optical disc capable of reducing the influence of variation in characteristics of a recording / playback device. The purpose of. It also provides a method for setting recording conditions for a writable optical disc in which recording pulse standard conditions are pre-recorded in a specific area, which can realize good recording characteristics even when there is a difference between the optical disc characteristics and the recording pulse standard conditions. The second purpose is to do. Another object of the third object is to provide an optical disc recording condition setting method capable of reducing the number of recording / playback times and shortening the time as compared with the optical disc recording condition setting method for achieving the second object.

【0009】

[Means for solving problems]

In order to achieve the first object described above, the recording pulse standard condition is read out from a writable optical disk in which the recording pulse standard condition is pre-recorded in a specific area, and the recording pulse condition of the recording / reproducing device is set. In the recording condition setting method of the optical disk for recording / reproducing data, among the recording pulse standard conditions, all of the plurality of mark front end pulse conditions defined by the combination of the front space length and the self-mark length, and the self-mark length and the rear All of the plurality of mark trailing end pulse conditions defined by the combination of space lengths are uniformly shifted by a predetermined amount of time, and the value corrected from the standard condition so that the jitter of the recording / playback signal becomes less than the allowable value is recorded / reproduced. Set as the recording pulse condition of the device to record and play back the data.

【0010】

Further, in order to achieve the second object described above, among the recording pulse standard conditions, each of a plurality of mark front end pulse conditions determined by the combination of the front space length and the self-mark length, and the self-mark length and the rear space. The recording pattern corresponding to each of the plurality of mark trailing end pulse conditions determined by the combination of lengths is recorded, and the value obtained by separately correcting each standard condition so that the jitter of the reproduction signal becomes less than the allowable value is recorded and reproduced. Set as the recording pulse condition of the device to record and play back the data.

【0011】

Further, in order to achieve the above-mentioned third object, among the recording pulse standard conditions, each of a plurality of mark front end pulse conditions defined by a combination of the selected front space length and the self-mark length was selected. Record the recording pattern corresponding to each of the plurality of mark trailing end pulse conditions defined by the combination of the self-mark length and the trailing space length, and set each standard condition separately so that the jitter of the reproduced signal becomes less than the allowable value. The corrected value is set as the recording pulse condition of the recording / playback device, and the value obtained by interpolation from the correction value of the selected recording pulse condition is set as the recording pulse condition of the recording / playback device for the recording pulse condition that is not selected. , Record and play back the data.

【0012】

The present invention according to the first aspect records the recording from a writable optical disk in which the recording pulse standard conditions that specify the position information of the recording pulse for each of a plurality of possible combinations of mark length and space length are recorded in advance. A method of reading out the pulse standard condition, modifying the recording pulse standard condition, and obtaining the optimum recording pulse condition, using the position information for all the mark length and space length combinations in the recording pulse standard condition. The first trial writing is performed on the optical disk, the first trial writing is reproduced, the first jitter is detected from the reproduced signal, and the position information for all the mark length and space length combinations in the recording pulse standard condition is used. A first predetermined amount of change is uniformly applied, a second trial writing is performed on the optical disk using the uniformly changed position information, the second trial writing is reproduced, and the second jitter is detected from the reproduced signal. This is a method of comparing the first jitter and the second jitter to obtain the recording pulse condition for selecting the position information used for the trial writing with the smaller jitter.

【0013】

The present invention according to the second aspect further applies a second predetermined amount of change uniformly to the position information for all combinations of mark length and space length under the recording pulse standard condition, and uses the uniformly changed position information. , Perform the third trial writing on the optical disk, reproduce the third trial writing, detect the third jitter from the reproduced signal, compare the first jitter, the second jitter, and the third jitter, and the one with less jitter. This is a method of obtaining the recording pulse condition of the first viewpoint of selecting the position information used for the trial writing of.

【0014】

The present invention according to the third aspect records the recording from a writable optical disk in which the recording pulse standard conditions that specify the position information of the recording pulse for each of a plurality of possible combinations of the mark length and the space length are recorded in advance. It is a method of reading out the pulse standard condition, modifying the recording pulse standard condition, and obtaining the optimum recording pulse condition, and is one of all the combinations of the mark length and the space length in the recording pulse standard condition. Using the position information for the combination, the first trial writing is performed on the optical disk, the first trial writing is reproduced, the first jitter is detected from the reproduced signal, and all the mark lengths under the recording pulse standard conditions are used. A first predetermined amount of change is added to the position information for any one of the above combinations of space lengths, a second trial writing is performed on the optical disk using the changed position information, and a second trial writing is performed. Is reproduced, the second jitter is detected from the reproduced signal, the first jitter and the second jitter are compared, and the recording pulse condition for selecting the position information used for the trial writing with the smaller jitter is obtained.

【0015】

The present invention according to the fourth aspect further changes by adding a second predetermined amount of change to the position information for any one of the above combinations of mark length and space length under the recording pulse standard condition. Using the position information, the third trial writing is performed on the optical disk, the third trial writing is reproduced, the third jitter is detected from the reproduced signal, and the first jitter, the second jitter, and the third jitter are compared. However, this is a method of obtaining the recording pulse condition from the third viewpoint of selecting the position information used for the trial writing with less jitter.

【0016】

In the present invention according to the fifth aspect, if there is a first position information selected for any one combination and a second position information selected for another combination, the position information in between the two combinations is present. Is a method of obtaining the recording pulse condition of the third viewpoint obtained by interpolating the first position information and the second position information.

【0017】

The present invention according to the sixth aspect records the recording from a writable optical disk in which the recording pulse standard conditions that specify the position information of the recording pulse for each of a plurality of possible combinations of the mark length and the space length are recorded in advance. A device that reads out the pulse standard conditions, modifies the recording pulse standard conditions, and obtains the optimum recording pulse conditions, and uses the position information for all the mark length and space length combinations in the recording pulse standard conditions. It has a trial writing means for performing the first trial writing on the optical disk and a jitter detecting means for reproducing the first trial writing and detecting the first jitter from the reproduced signal. The trial writing means is the recording pulse. A first predetermined amount of change is uniformly applied to the position information for all combinations of mark length and space length under the standard conditions, and a second trial writing is performed on the optical disk using the uniformly changed position information, and the above jitter is performed. The detection means reproduces the above-mentioned second trial writing, detects the second jitter from the reproduced signal, compares the first jitter and the second jitter, and uses the position information used for the trial writing with the smaller jitter. It is an apparatus for obtaining a recording pulse condition having a selection means for selection.

【0018】

In the present invention according to the seventh aspect, the above-mentioned trial writing means uniformly changes the position information for all combinations of mark length and space length under the recording pulse standard condition by uniformly changing a second predetermined amount. Using the position information, the third trial writing is performed on the optical disk, the jitter detecting means reproduces the third trial writing, the third jitter is detected from the reproduced signal, and the selection means is the first. It is a device that compares the jitter, the second jitter, and the third jitter, and selects the position information used for the trial writing with the smaller jitter, and obtains the recording pulse condition from the sixth viewpoint.

【0019】

The present invention according to the eighth aspect records the recording from a writable optical disk in which the recording pulse standard conditions that specify the position information of the recording pulse for each of a plurality of possible combinations of the mark length and the space length are recorded in advance. A device that reads out the pulse standard conditions, modifies the recording pulse standard conditions, and obtains the optimum recording pulse conditions, and is one of all the combinations of mark length and space length in the recording pulse standard conditions. It has a trial writing means for performing the first trial writing on the optical disk using the position information for the combination, and a jitter detecting means for reproducing the first trial writing and detecting the first jitter from the reproduced signal. The trial writing means adds a first predetermined amount of change to the position information for any one of the above combinations of the mark length and the space length under the recording pulse standard condition, and uses the changed position information. , The second trial writing is performed on the optical disk, the jitter detecting means reproduces the second trial writing, detects the second jitter from the reproduced signal, and further compares the first jitter and the second jitter. This is a device for obtaining a recording pulse condition having a selection means for selecting the position information used for the trial writing with less jitter.

【0020】

In the present invention according to the ninth aspect, the above-mentioned trial writing means further provides a second predetermined amount of position information for any one of the above combinations of mark length and space length under the recording pulse standard condition. The third trial writing is performed on the optical disk using the changed position information, and the jitter detecting means reproduces the third trial writing, detects the third jitter from the reproduced signal, and performs the above. The selection means is a device that compares the first jitter, the second jitter, and the third jitter, and obtains the recording pulse condition of the eighth viewpoint of selecting the position information used for the trial writing with the smaller jitter.

【0021】

In the present invention according to the tenth aspect, if there is a first position information selected for any one combination and a second position information selected for another combination, the position information in between the two combinations is present. Is a device for obtaining the recording pulse condition of the eighth viewpoint obtained by interpolating the first position information and the second position information.

【0022】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, as preferred embodiments of the present invention, three embodiments will be described using a specific optical disc and a recording / playback device.

【0023】

First, the recording method used in this embodiment will be described. When writing data to an optical disc, a multi-pulse mark edge recording method is used, and the data is written to the optical disc as mark and space length information. In addition, it is assumed that a modulation method is used in which the mark length is 3T to 14T (T is the time for one clock cycle) and the space length is a combination of integer values of 3T to 14T. Further, in the present embodiment, the marks having lengths of 3T, 4T and 5T or more (abbreviated as 3Tm, 4Tm, 5Tm) and the spaces having lengths of 3T, 4T and 5T or more (abbreviated as 3Ts, 4Ts, 5Ts). ), It is assumed that distortion of the mark shape and thermal interference between marks occur at the boundary between the mark and the space. For one mark, there are two parts adjacent to the space, the front end and the rear end of the mark. Therefore, the recording state of the correct mark length is achieved by compensating for the edge position of the recording pulse used at the time of recording with these combinations. If the combination of 5Tm or more and 5Ts or more is one combination, there are 9 combinations of 3x3 pulse conditions at the front end of the mark and 9 combinations of 3x3 pulse conditions at the rear end of the mark, and different value conditions are set for each. It has a total of 18 condition settings. FIG. 2 is a table of the values of the mark front end pulse condition and the mark rear end pulse condition. For example, in Table (A) of FIG. 2, "5Ts5Tm" in the upper left indicates that the condition of the mark front end pulse at the boundary between the space of 5T or more and the mark of 5T or more following it is included. In Table (B) of FIG. 2, "3Tm5Ts" in the upper right indicates that the condition of the mark trailing end pulse at the boundary between the 3T mark and the space of 5T or more following it is included.

【0024】

As shown in Fig. 3, "5Ts5Tm" (Ts comes first, Tm comes after) in the table of Fig. 2 is the tip edge of the recording pattern to be recorded on the optical disk and the continuous recording for actually driving the laser. The positional relationship with the first pulse of the pulse is shown, and "5Tm5Ts" (Tm comes first, Ts comes after) is the end edge of the recording pattern you want to record on the optical disc and the continuous recording pulse for actually driving the laser. The positional relationship with the last pulse of is shown. That is, FIG. 3 shows the relationship between the mark space on the disk and the recording pulse for these values.

【0025】

For example, if the mark front end pulse condition in FIG. 2 is 3Ts5Tm, the condition when the self-mark length is 5Tm or more and the space length immediately before it is 3Ts is defined. The condition at this time is, as shown in the lower left of FIG. 3, when recording a mark of 5T or more next to the 3T space, the front end position of the recording pulse is recorded at the tip edge of the recording pattern (that is, the boundary between the space and the mark). ) Is followed by a value of 3Ts5Tm, and the laser recording is performed with a time lag.

【0026】

The 18 conditions shown in Fig. 2 are determined using the representative disc that serves as the reference for the characteristics and the representative recording / playback device that serves as the reference. The determined recording pulse condition shall be recorded in advance in a specific area on the optical disc as the recording pulse standard condition. The standard conditions for recording pulses also include other items, such as the width of the head pulse of the recording pulse, the width of the intermediate pulse, the width of the final pulse, and the width of the cooling pulse attached after the final pulse. In the present embodiment, as an example, a pulse condition whose value changes adaptively depending on the combination pattern of the mark and the space to be recorded will be described.

【0027】

(Embodiment 1) FIG. 1 is a block diagram of an optical disc recording / playback device that realizes the method for setting recording conditions for an optical disc of the present invention. First, the components and signals will be described. 1 is a phase change type optical disk to which data can be written, 2 is a motor that rotates optical disk 1, 3 is a head that reads recorded data from rotating optical disk 1 and obtains a reproduction signal 4, and 5 is a reproduction signal 4. After correcting the frequency characteristics, the equalizer binarization means for obtaining the digital binarization signal 6 from the analog reproduction signal by the duty feedback slicing method, 7 detects the edge of the binarization signal 6 and synchronizes with it. A PLL that generates a reproduction clock, converts the binarized signal 6 into data 8 synchronized with the reproduction clock, and outputs the time lag between the edge of the reproduction clock and the edge of the binarization signal 6 as a phase error pulse 11. Means, 9 is a recording pulse standard condition demodulation means that detects the recording pulse standard condition 10 from the data 8, and 12 is a phase error pulse 11 separated by Hi or Lo of the binarization signal 6, and the average value of the pulse widths is the voltage. A jitter measuring means that converts to and outputs the mark front end jitter voltage 13 and the mark rear end jitter voltage 14, and 22 stores the past values of the mark front end jitter voltage 13 and the mark rear end jitter voltage 14 and sets them as predetermined allowable values. The recording / playback control means that outputs the correction value 23 according to the magnitude relationship of, 25 is the changing means that generates the amount of change to be added to the value of the recording pulse standard condition 10, and outputs the amount of change as the correction value 23, 24 is the recording pulse standard. The recording pulse condition correction means that outputs the value obtained by adding the correction value 23, which is the amount of change, to the value of condition 10 as the recording pulse condition setting value 18, and 15 generates the recording pattern 16 used to determine the recording pulse condition. The pattern generating means, 17 is a recording compensating means for converting the recording pattern 16 into multi-pulse data 19 based on the recording pulse condition set value 18, and 20 drives the laser mounted on the head 3 with a predetermined current according to the multi-pulse data 19. It is a laser driving means. The head 3 emits laser light with a current 21 supplied from the laser driving means 20, and the light is emitted.

【0028】

The jitter measuring means 12 measures as follows.

【0029】

In FIG. 11, the waveform (A) is a recording pattern generated from the pattern generating means 15, the waveform (B) is a recording pulse generated from the laser driving means 20, and the waveform (C) is a recording mark and a waveform (D). ) Indicates the reproduction signal 4 obtained from the head 3, the waveform (E) indicates the binarization signal obtained from the equalizer binarizing means 5, and the waveform (F) indicates the reproduction clock generated in the PLL means 7. .. Waveforms (G), (H), and (I) show the measured values of jitter when they are different. In any of the waveforms (G), (H), and (I) shown in FIG. 11, at the position where the recording pattern corresponds to the tip edge of the 8 Tm pulse, the tip edge of the binarized signal and the edge of the reproduction clock are Since they are synchronized, there is a jitter distribution centered on the synchronized points. At the position where the recording pattern corresponds to the tip edge of the 4 Tm pulse in FIG. 11, when the tip edge of the binarized signal is ahead of the edge of the reproduction clock (waveform (G)), it is synchronized (waveform (G)). Waveform (H)) and when delayed (waveform (I)) are shown. If it is advanced, there is a jitter distribution centered on the advanced point. If they are synchronized, there is a jitter distribution centered on the synchronized point, and if they are delayed, there is a jitter distribution centered on the delayed point. Such jitter distributions are collected on the time axis and superposed are shown at the right ends of the waveforms (G), (H), and (I). If there are many cases of synchronization (waveform (H)), the spread width of the superimposed jitter distribution is narrow. If it is advanced (waveform (G)) or lagging (waveform (I)), the spread of the superimposed jitter distribution becomes wide. In this way, the jitter distribution for the mark front end jitter is collected at regular time intervals, and the superposed result is output as the signal 13. In addition, the jitter distribution for the mark trailing edge jitter is collected, and the superposed result is output as a signal 14. These signals 13 and 14 represent the degree of jitter and are sent to the recording / playback control means 22 as a measurement result.

【0030】

The pattern generating means 15 includes a random pattern generator 15a that generates a random pattern and a predetermined pattern generator 15b that generates a predetermined predetermined pattern. In the first embodiment, the random pattern generator 15a is used, and in the second embodiment, the predetermined pattern generator 15b is used.

【0031】

The changing means 25 includes a uniform changer 25a that uniformly changes all nine default values under the recording pulse standard condition, and an individual changer 25b that changes the nine default values one by one individually. ..

【0032】

Next, the operation steps of the present embodiment will be described. The first step is to read the recording pulse standard conditions pre-recorded on the optical disc 1. For this purpose, the spot is moved to a specific area of the optical disc 1 on which the head 3 rotates, and a track of a pre-recorded recording pulse standard condition is traced. The reproduced signal 4 at this time is converted into the binarized signal 6 by the equalizer binarizing means 5, and the data 8 synchronized by the PLL means 7 is obtained. Next, the recording pulse standard condition 10 is extracted from the data 8 by the recording pulse standard condition demodulation means 9. Tables (B) and (E) of FIG. 6 are specific examples of the recording pulse standard condition 10. In Table (B), the default values for all combinations at the mark tip are set as the mark front end pulse conditions, and in Table (E), the default values for all combinations at the mark end are set as the mark rear end pulse conditions. It is set. The units of numerical values 2, 4, 6, etc. shown in the table are nanoseconds, and the recording clock period T is 17 nanoseconds.

【0033】

The second step is to test-write data on an optical disc under standard recording pulse conditions. For this purpose, first, the laser spot of the head 3 is moved to the writable track of the optical disk 1. The pattern generating means 15 generates a random signal 16 from the random pattern generator 15a as a recording pattern. The above-mentioned recording pulse standard condition 10 is output as the recording pulse condition setting value 18 as it is without being corrected by the recording pulse condition correction means 24. The recording compensation means 17 converts the random signal 16 into multi-pulse data 19 based on the recording pulse condition set value. For example, as shown in FIG. 8, if the random signal 16 contains a signal of 6Ts4Tm (4T mark following 6T space), the leading edge of the recording pulse for the 4T mark is + from Table (B) in FIG. 4 nanoseconds Shifted along the time axis. Further, as shown in FIG. 8, when the random signal 16 contains a signal of 4Tm6Ts (6T mark following the 4T mark), the edge of the last pulse of the recording pulse with respect to the 4T mark is shown in Table (E) of FIG. Shifts from to -25 nanoseconds along the time axis. The shift of the tip pulse or the tail pulse may be such that the entire pulse is shifted or the tip edge of each pulse is shifted. The multi-pulse data 19 in which the tip pulse and the tail pulse are shifted in this way is converted into a current 21 for driving the laser in the laser driving means 20 and supplied to the head 3. The head 3 records on the writable track.

【0034】

The third step is to reproduce the random data trial-written using the multi-pulse data 19 in which the pulse is shifted under the recording pulse standard condition, and measure the jitter of the reproduced signal. For this purpose, the track recorded in the second step is reproduced by the head 3, and the binarization signal 6 is obtained by the equalizer binarization means 5. A reproduction clock is generated from the binarization signal 6 by the PLL means 7, and the phase error pulse 11 of the reproduction clock and the binarization signal is output. The jitter measuring means 12 separately detects the mark front end jitter voltage 13 and the mark rear end jitter voltage 14. The mark front end jitter voltage Vf (0) and the mark rear end jitter voltage Vr (0), which are the detected results, are stored in the recording / reproduction control means 22. Here, 0 in parentheses indicates that it is a standard condition. If the jitter voltages Vf (0) and Vr (0) are recorded, the changing means 25 is notified to that effect, and then the fourth step is performed.

【0035】

In the fourth step, the uniform changer 25a included in the changing means 25 uniformly changes the recording pulse standard condition 10 sent from the recording pulse standard condition demodulation means 9, that is, shifts the time and tries the data on the optical disk. Write. The recording pulse standard conditions are shown in Tables (B) and (E) of Fig. 5, and examples of uniform changes in these tables (B) and (E) are shown in Tables (A) and (D). ing. In FIG. 5, the two tables (B) and (E) above and below the center are the standard recording pulse conditions read from the disc. The table (A) on the left shows the correction value obtained by uniformly adding 1 to the value of the recording pulse standard condition of the mark front end pulse. The table (D) on the left shows the correction value obtained by uniformly adding -1 to the value of the recording pulse standard condition of the mark trailing end pulse. Similarly, the table (C) on the right side shows the correction value obtained by uniformly adding -1 to the value of the recording pulse standard condition of the mark front end pulse, and the table (F) on the right side shows the recording pulse condition of the mark rear end pulse. The correction value obtained by uniformly adding 1 to the value of is shown. Examples of specific numerical values in Tables (A) to (F) of FIG. 5 are shown in Tables (A) to (F) of FIG. 6, respectively.

【0036】

In the fourth step, it is assumed that a trial writing is performed using the correction values of the table (A) having the front end +1 and the table (D) having the rear end -1. The uniform changer 25a outputs +1 for the mark front end pulse condition and -1 for the mark rear end pulse condition as the correction value 23. In the recording pulse condition correction means 24, the correction value 23 is added to the recording pulse standard condition 10 and the recording pulse condition setting value 18 is output. Hereinafter, a random signal is recorded on the optical disk 1 in the same manner as in the second step.

【0037】

The fifth step reproduces the random data recorded in the fourth step and measures the jitter of the reproduced signal. In the same manner as in the third step, the mark front end jitter voltage Vf (+1) and the mark rear end jitter voltage Vr (-1) are stored in the recording / reproduction control means 22. Here, the numerical values in parentheses indicate the amount of change from the standard conditions.

【0038】

Further, the fourth and fifth steps are repeated while changing the correction value 23, and the jitter voltage is collected. For example, as shown in FIG. 4, the correction values 23 of the mark front end pulse condition and the mark rear end pulse condition are paired with (+1, -1), (+2, -2), (-1, +). It changes to 1) and (-2, +2). Examples of changes to (+1 and -1) are shown in Tables (A) and (D) of Fig. 5, and specific numerical values are shown in Tables (A) and (D) of Fig. 6. .. In this embodiment, the amount of change +1 represents a change of +1 nanosecond. In this way, the recording pulse standard condition is uniformly changed by the correction value 23, and the plotted points as shown in FIG. 4 are recorded in the recording / playback control device 22.

【0039】

FIG. 4 shows two examples of the measurement results of the jitter voltages Vf and Vr obtained by uniformly changing the correction value 23 as described above. The pair of the mark front end pulse condition and the mark rear end pulse condition when the jitter voltage is below the permissible value or the lowest value is adopted. If the characteristics of the optical disc used, the pre-written recording pulse standard conditions, and the characteristics of the recording / playback device match, the mark front end when the correction value is 0 as shown in Fig. 4 (A). Both the jitter voltage Vf at the mark and the jitter voltage Vr at the trailing edge of the mark are smaller than the minimum or allowable value. On the other hand, if the characteristics of the optical disc used, the pre-written recording pulse standard conditions, and the characteristics of the recording / playback device do not match, as shown in Fig. 4 (B), the jitter at the rear end of the mark. When the correction value is 0, the voltage exceeds the permissible value, and when the correction value is not 0, the jitter becomes the minimum or the permissible value or less.

【0040】

The embodiment of the present invention is a recording condition setting method focusing on the uniform correction of the recording pulse condition and the change of the reproduction jitter, and is a combination of the mark front end jitter and the mark rear end jitter obtained by trial writing under each condition. Among them, a combination in which the larger of the front end and the rear end jitter is the minimum value or the allowable value or less is used as the optimum recording condition of the apparatus.

【0041】

In the sixth step, the recording pulse condition setting value to be used in the recording / playback device thereafter is determined by the jitter voltage collected in the fourth and fifth steps. In the recording / playback control means 24 of FIG. 1, from the set of the mark front end jitter voltage and the mark rear end jitter voltage for each correction value, the correction value in which the larger of the front end and the rear end jitter voltages is equal to or less than the allowable value is selected. , Used as the recording condition of the subsequent recording / playback device.

【0042】

Assuming that the allowable value or less is the adoption condition, in the case of FIG. 4B, a pair in which the correction values of the mark front end pulse condition and the mark rear end pulse condition are (-1, +1) may be adopted. , A pair in which the correction values of the mark front end pulse condition and the mark rear end pulse condition are (0, +1) may be adopted.

【0043】

The adopted correction value is used when recording an optical disc currently loaded in the recording / playback device.

【0044】

By the above steps, the embodiment of the present invention reads out the recording pulse standard conditions pre-recorded on the optical disk, and among the recording pulse standard conditions, a plurality determined by the combination of the front space length and the self-mark length. All the mark front end pulse conditions and all the multiple mark rear end pulse conditions determined by the combination of the self-mark length and the rear space length are uniformly shifted for a certain amount of time, and the jitter of the recording / playback signal is less than the allowable value. The value corrected from the standard condition is set as the recording pulse condition of the recording / reproducing device so that the data is recorded / reproduced. By this method, it is possible to reduce the influence of variations in the characteristics of the writable optical disc and the recording / reproducing device, and to always realize the optimum recording / reproducing state of the optical disc.

【0045】

In the present embodiment, the correction value 23 is described by a method in which the mark rear end pulse condition is decremented by 1 when the mark front end pulse condition is +1. However, the correction value is not limited to this value, and the front end and the rear end are not limited to this value. There are various combinations within the range of uniformly correcting each of the above conditions, and the effect of the present invention that minimizes jitter can be exhibited even with other correction values.

【0046】

(Embodiment 2) Next, in the second embodiment, good recording is performed even when there is a difference between the optical disc characteristics and the recording pulse standard condition of the writable optical disc in which the recording pulse standard condition is pre-recorded in a specific area. A method for setting recording conditions for an optical disc that can realize the characteristics will be specifically described. The second embodiment will also be described with reference to FIG. The parts different from those of the first embodiment will be described, and the same parts will be omitted. In the present embodiment, of the 18 recording pulse conditions, the recording pulse standard conditions are used as they are for the two values of 5Ts5Tm and 5Tm5Ts. Furthermore, in order to determine the remaining 16 recording pulse conditions, 12 types of recording patterns corresponding to each are used. Such 12 types of recording patterns are generated by the predetermined pattern generator 15b of the pattern generating means 15.

【0047】

Figure 7 shows the relationship between each recording pulse condition and the recording pattern used.

【0048】

For example, the recording pattern (1) shown in FIG. 7 (A) is used to determine the mark front end pulse condition 5Ts4Tm with a self-mark length of 4Tm and a front mark length of 5Ts or more. The recording pattern (1) is a repeating signal of 8Tm, 6Ts, 4Tm, and 6Ts. All recording patterns have the same total mark length and total space length, and contain two marks and two spaces to change the edge to be determined, and the other three edges are fixed and used. It is characterized by that. In FIG. 7, the front edge of the mark to be changed is represented by , and the rear edge of the mark to be changed is represented by . The rest are all fixed edges.

【0049】

The operation steps of this embodiment will be described. In the following, an example of using the recording pattern (1) to determine the mark front end pulse condition 5Ts 4Tm with a self-mark length of 4Tm and a front mark length of 5Ts or more will be described in detail, but the steps for determining other recording pulse conditions are recorded. The same is true except that the patterns are different.

【0050】

First, the first step reads out the recording pulse standard conditions pre-recorded on the optical disc 1. This step is the same as in the first embodiment.

【0051】

The second step is to test-write a predetermined recording pattern (1) on an optical disc in order to determine the recording pulse condition of 5Ts4Tm. The recording pulse standard condition of 5Ts4Tm is output as it is as the recording pulse condition setting value 18, and the recording compensation means 18 converts the recording pattern (1) into multi-pulse data 19 based on the recording pulse condition setting value. The multi-pulse data 19 is converted into a current 21 for driving the laser in the laser driving means 20 and supplied to the head 3. The head 3 records on the writable track.

【0052】

The third step is to reproduce the test-written recording pattern (1) and measure the jitter of the reproduced signal. For this purpose, the track recorded in the second step is reproduced by the head 3, and the binarization signal 6 is obtained by the equalizer binarization means 5. A reproduction clock is generated from the binarization signal 6 by the PLL means 7, and the phase error pulse 11 of the reproduction clock and the binarization signal is output. The jitter measuring means 12 outputs a signal 13 representing the mark front end jitter voltage Vf (0) with the average value of the widths of the phase error pulses 11 as the jitter voltage. Here, 0 in parentheses means that the amount of change of the recording pulse with respect to the changing edge of the recording pattern (1) is 0, that is, the default value 4 from the recording pulse standard condition 10 (in Table (B) of FIG. 6). (Value of the part corresponding to 5Ts4Tm) is the jitter voltage obtained as a result of using it as it is. Since this step is for determining the mark front end pulse condition, only the mark front end jitter voltage Vf is detected. On the contrary, when the mark rear end pulse condition is obtained, only the mark rear end jitter voltage Vr is detected. The detected mark front end jitter voltage Vf (0) is stored in the recording / playback control means 22. If the jitter voltage Vf (0) is recorded, the changing means 25 is notified to that effect, and then the fourth step is performed.

【0053】

In the fourth step, first, the individual changer 25b in the changing means 25 outputs, for example, +1 as the correction value 23 for the default value 4 of the mark front end pulse condition 5Ts4Tm. The recording pulse condition correction means 24 outputs a value 5 obtained by adding the correction value 23 +1 to the default value 4 of 5Ts4Tm included in the recording pulse standard condition 10 as the recording pulse condition setting value 18. Hereinafter, the recording pattern (1) is recorded on the optical disc 1 in the same manner as in the second step.

【0054】

The fifth step reproduces the recording pattern (1) recorded in the fourth step and measures the jitter of the reproduced signal. In the same manner as in the third step, the mark front end jitter voltage Vf (1) is stored in the recording / reproducing control means 22. Further, the fourth and fifth steps are repeated while changing the correction value 23, and the jitter voltage is collected.

【0055】

Here, the recording / playback waveforms when the correction value 23 of the recording pulse condition 5Ts4Tm is changed to +1, +2, and +3 using the recording pattern (1) are shown in FIGS. 8, 9, and 10, respectively.

【0056】

5Ts4Tm in Fig. 8 (B) is corrected by +1. When recording under this condition, the front edge position of the recorded 4T mark becomes the ideal position as shown in Fig. 8 (C). Compared to the left. Therefore, there is a phase error pulse (FIG. 8 (F)) that represents the phase shift between the binarized signal (FIG. 8 (E)) obtained by binarizing the reproduced signal (FIG. 8 (D)) and the reproduction clock (FIG. 8 (F)). G)) has a wider width at the front edge of the 4T mark. Therefore, the jitter voltage Vf (+1), which indicates the average value of the widths of the phase error pulses, is large.

【0057】

In addition, 5Ts4Tm in Fig. 9 (B) is corrected by +2, and when recorded under this condition, the front edge of the recorded 4T mark is at the ideal position as shown in Fig. 9 (C). is there. Therefore, the binarized signal (Fig. 9 (E)) obtained by binarizing the reproduced signal (Fig. 9 (D)) and the phase error pulse (Fig. 9 (F)) representing the phase shift of the reproduced clock (Fig. 9 (F)). G)) are all narrow. Therefore, the jitter voltage Vf (+2), which indicates the average value of the widths of the phase error pulses, is small.

【0058】

Furthermore, 5Ts4Tm in Fig. 10 (B) is corrected by +3, and when recorded under this condition, the front edge position of the recorded 4T mark is ideal as shown in Fig. 10 (C). It is shifted to the right compared to the position. Therefore, there is a phase error pulse (FIG. 10 (F)) that represents the phase shift between the binarized signal (FIG. 10 (E)) obtained by binarizing the reproduced signal (FIG. 10 (D)) and the reproduction clock (FIG. 10 (F)). In G)), the width becomes thicker at the front edge of the 4T mark. Therefore, the jitter voltage Vf (+3), which indicates the average value of the widths of the phase error pulses, is large.

【0059】

The embodiment of the present invention is a recording condition setting method focusing on the correction condition of the recording pulse condition and the change of the reproduction jitter voltage, and the mark front end jitter obtained by trial writing under each condition is less than or equal to the allowable value or the minimum. It is characterized in that the correction value is used as the optimum recording condition of the apparatus.

【0060】

In the sixth step, the set value of the recording pulse condition 5Ts4Tm to be used in the recording / playback device thereafter is determined by the jitter voltage Vf collected in the fourth and fifth steps. That is, the case where the jitter voltage Vf is equal to or less than the minimum value or the allowable value is obtained from the results of a plurality of trial writings and their readings, and the correction value in that case is adopted. In the case of the examples shown in FIGS. 8, 9, and 10, +2 is adopted as the correction value of the mark front end pulse condition 5Ts4Tm. In this way, in the recording / reproducing control means 24 of FIG. 1, the correction value at which the mark front end jitter voltage for each correction value becomes equal to or less than the allowable value or the minimum is selected, and the value of the mark front end pulse condition 5Ts4Tm of the subsequent recording / reproducing apparatus Used as.

【0061】

In the same manner thereafter, test writing is performed using the recording pattern (1) to determine the mark rear end pulse condition 4Tm5Ts, and the correction value at which the mark rear end jitter voltage Vr is less than or equal to the allowable value is selected, and thereafter. It is used as the value of the mark trailing end pulse condition 4Tm5Ts of the recording / playback device. Next, perform trial writing using the recording pattern (2) to determine the mark front end pulse condition 4Ts5Tm, select the correction value that makes the mark front end jitter voltage Vf less than or equal to the allowable value, and then record and play back. Used as the value of the device mark front end pulse condition 4Ts5Tm. In this way, the second step to the sixth step are repeated while changing the recording pattern.

【0062】

By the above steps, in the embodiment of the present invention, the recording pulse standard conditions pre-recorded on the optical disk are read out, and among the recording pulse standard conditions, a plurality determined by the combination of the front space length and the self-mark length. Record the recording patterns (Figs. 7 (A) to (P)) corresponding to each of the mark front end pulse conditions and each of the plurality of mark rear end pulse conditions determined by the combination of the self-mark length and the rear space length. Data is recorded and reproduced by setting the value obtained by separately correcting each standard condition as the recording pulse condition of the recording / reproducing device so that the jitter of the reproduction signal becomes less than or equal to the allowable value or the minimum. By this method, even if there is a difference between the characteristics of the writable optical disc and the standard recording pulse condition, each value of the recording pulse condition can be corrected to the optimum value by the combination of the optical disc to be used and the recording / reproducing device. , It is possible to always realize a good recording / playback state of an optical disc.

【0063】

(Embodiment 3) Next, a specific example of a method of reducing the number of recordings and reproductions and shortening the time from the step of the second embodiment will be described. In FIG. 2, when the mark front end pulse condition is 5Ts3Tm, it is determined according to the above-described second embodiment using the recording pattern (3) of FIG. In FIG. 2, when the mark front end pulse condition is 3Ts3Tm, the determination is made using the recording pattern (11) in FIG. Here, in order to determine the case where the mark front end pulse condition is 4Ts3Tm, the correction value of 5Ts3Tm obtained and the value of 5Ts3Tm of the standard condition are obtained instead of determining using the recording pattern (7). From the relationship between the correction value of 3Ts3Tm, the value of 3Ts3Tm under the standard condition, and the value of 4Ts3Tm under the standard condition, the correction value of 4Ts3Tm is obtained by calculation such as interpolation. Since the operation of determining the correction value of 4Ts3Tm is an electrical calculation operation, the required time is much shorter than when the recording pattern (7) is actually recorded and reproduced.

【0064】

That is, the embodiment of the present invention is characterized in that all recording pulse conditions are not determined by recording and reproduction of each corresponding recording pattern, but some conditions are interpolated by calculation from other conditions.

【0065】

For this purpose, in the recording / playback apparatus of the optical disc of FIG. 1, among the recording pulse standard conditions, each of a plurality of mark front end pulse conditions determined by the combination of the selected front space length and the self-mark length, and the selected self The recording pattern corresponding to each of the plurality of mark trailing end pulse conditions defined by the combination of the mark length and the trailing space length is recorded, and each standard condition is corrected separately so that the jitter of the reproduced signal becomes less than the allowable value. The value is set as the recording pulse condition of the recording / reproducing device (the above is partly the same as the step of the second embodiment). For the recording pulse condition not selected in the recording / reproducing control means 24, a value obtained by interpolation from the correction value of the selected recording pulse condition is set as the recording pulse condition of the recording / reproducing apparatus, and data is recorded / reproduced. .. As a result, the time required to complete setting all the recording pulse conditions can be significantly reduced.

【0066】

In the present embodiment, 5Ts5Tm and 5Tm5Ts of the recording pulse conditions show an example in which the recording pulse standard conditions read from the optical disc are used as they are, but the present invention is not limited to this, and for example, a repeating signal of 6Tm6Ts is used. The recording condition setting method of the present invention may be applied after making correction by a method of recording and detecting asymmetry or duty. Furthermore, as the recording pattern, the pattern shown in FIG. 7 was used, but the total mark length and the total space length were the same, two marks and two spaces were included, and at least one edge of the attribute to be determined was defined. Jitter detection is possible if the pattern includes it.

【0067】

Further, although the recorded waveform has been described with the example of binary power in the first embodiment and the second embodiment, the same effect can be obtained even when the power is multi-valued. Further, although the case where the recording pulse condition is 18 of 3 × 3 × 2 has been described, the same can be performed even if the number of parameters increases such as 4 × 4 × 2. However, the recording pattern used in the second embodiment needs to be increased according to the number of parameters.

【0068】

[Effect of the invention]

As described above, according to the recording condition setting method of the optical disc of the present invention, the recording pulse standard condition is read out from a writable optical disc in which the recording pulse standard condition is pre-recorded in a specific area, and the recording / playback apparatus is used. In the recording condition setting method for an optical disc that sets recording pulse conditions and records / reproduces data, it is possible to reduce the influence of variations in the characteristics of a writable optical disc and a recording / reproducing device. Further, it is possible to realize good recording characteristics even when there is a difference between the optical disc characteristics and the recording pulse standard conditions of a writable optical disc in which the recording pulse standard conditions are pre-recorded in a specific area. Therefore, the yield during mass production of optical discs and recording / playback devices is improved, which is effective in improving product quality and reducing costs.

[Simple explanation of drawings]

[Figure 1]

Block diagram of an optical disc recording / playback device according to an embodiment of the present invention [Figure 2]

Table showing recording pulse conditions [Fig. 3]

Explanatory drawing of recording pulse condition [Fig. 4]

Characteristic graph showing the jitter measurement result in the first embodiment [Fig. 5]

Table of uniform time shifts in Embodiment 1 [Fig. 6]

A table showing specific numerical values for uniform time shifts [Fig. 7]

Recorded pattern waveform diagram in the second embodiment [Fig. 8]

Waveform diagram showing recording / playback operation in the second embodiment [Fig. 9]

Waveform diagram showing recording / playback operation in the second embodiment [Fig. 10]

Waveform diagram showing recording / playback operation in the second embodiment [Fig. 11]

Waveform diagram showing the method of jitter measurement [Explanation of symbols]

1 optical disc 2 motor 3 heads 4 Playback signal 5 Equalizer binarization means 6 Binarized signal 7 PLL means 8 data 9 Recording pulse standard condition demodulation means 10 Recording pulse standard conditions 11 Phase error pulse 12 Jitter measuring means 13 Mark front end jitter voltage 14 mark rear end jitter voltage 15 Pattern generation means 16 Recording pattern 17 Record compensation means 18 Recording pulse condition setting value 19 Multi-pulse data 20 Laser drive means 21 Recording current 22 Recording / playback control means 23 Correction value 24 Recording pulse condition correction means 25 Means of change