JP2002074668A - Optical disk recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of malfunction such as increase in error in recording parameter to be obtained or the obtainment of erroneous values, when the property of a recording track (sector) to be used is deteriorated due to defect or expiration of its life at test recording or reproducing operation to obtain recording pulse condition. SOLUTION: The quality of recording tracks for each sector is inspected and discriminated by recording and reproducing a single signal with respect to the objective recording track and taking the reproduced jitter values for each obtained sector as the reference for the discrimination. Further, a test pattern is recorded and reproduced while changing the recording condition for each sector with respect to the already inspected recording track, then the optimum value of the recording pulse condition is searched by taking the average jitter value for each obtained recording condition as the reference for the discrimination. Since the same recording conditions are radially and dispersedly arranged (figure 1) as to the recording track, the influence of the variance of the property in the circumferential direction of an optical disk is suppressed to the minimum when averaging process is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk recording / reproducing apparatus for obtaining optimum recording conditions by performing test recording / reproducing on a recording track of an optical disk.

[0002]

2. Description of the Related Art A DVDRAM is an example of an optical disk capable of rewriting a large amount of data. Discs and devices capable of recording 4.7 GB data on one side of a 12 cm diameter optical disc using a phase change recording film are being put to practical use. The inventor of the present application performed a test recording / reproduction in a high-density optical recording / reproducing apparatus such as a DVDRAM, and was able to determine an optimum recording condition in any combination of a disk and a device. We have been studying the equipment. (Reference: Japanese Patent Application No. 11-313657). The test recording / reproduction is performed using a track in a drive test zone provided in advance in the disc or using a track in which data in the user area is not recorded. The present invention has been invented so that the recording pulse conditions can be determined more accurately when the technique of the above-mentioned prior application is implemented.

[0003]

If the characteristics of the recording track on which the test recording / reproduction is performed are deteriorated for some reason, the error of the obtained recording pulse condition becomes large or the wrong recording pulse condition is obtained. There was a problem of getting it. Possible causes of track deterioration include defects (adhesion of dust and scratches), deterioration of the recording film due to previous recording with excessive recording power, and life of the disc due to repeated use. There are cases where the recording track (or sector) does not have sufficient recording / reproducing characteristics necessary to determine the recording conditions.

The recording / reproducing characteristics of an optical disk are liable to cause variations in characteristics in the circumferential direction of a rotating disk due to the eccentricity and runout of the disk. Further, the characteristics of the individual sectors constituting the track may vary depending on the past use history. When test recording / reproducing is performed in a state where there is a characteristic variation in the disk circumferential direction, there is a problem that an error is included in a recording pulse condition obtained by using sectors having different locations in the disk circumferential direction.

On the other hand, it is considered that the aforementioned error can be reduced by performing test recording and reproduction using a large number of recording tracks (or sectors) and simply averaging the results. There is a problem that it takes longer in proportion to the number of times of reproduction.

The present invention has been made to solve the above-mentioned problems, and in order to improve the accuracy of obtaining a recording pulse condition when performing test recording and reproduction, a recording track (sector) is used.
To provide an optical disk recording / reproducing apparatus capable of previously inspecting the recording / reproducing quality of an optical disk and selecting an area having good characteristics, and an optical disk recording / reproducing apparatus capable of effectively reducing a characteristic variation in a circumferential direction of an optical disk without increasing a required time. It is intended to provide a device.

[0007]

In order to achieve the above-mentioned object, an optical disk recording / reproducing apparatus according to the present invention records a random signal on a recording track having a plurality of sectors distinguished for each predetermined information amount. A recording means for overwriting a single signal, a reproduction jitter measuring means for reproducing a recording track on which the single signal is recorded and measuring a reproduction jitter for each sector, and a condition 1 in which the reproduction jitter is smaller than a predetermined value 1.
A track jump unit for replacing a recording track when the number of sectors satisfying the condition 2 is not less than a predetermined value 2 and the number of a sector satisfying the condition 1 in a recording track satisfying the condition 2 is stored. Before performing test recording / reproduction, a recording track satisfying the condition 2 is selected, and a sector satisfying the condition 1 is stored.

When N and M are integers of 2 or more, a test pattern is applied to a recording track having N × M or more sectors distinguished for each predetermined information amount while changing recording conditions for each sector. Recording means for performing N-sector recording and repeating the N-sector recording M times, and reproducing jitter measuring means for reproducing a recording track on which the test pattern is recorded and measuring a reproducing jitter for each sector, under the same recording conditions. A reproduction jitter averaging means for obtaining N reproduction jitter average values of sectors satisfying the condition 1 according to claim 1 out of the M sectors obtained for each recording condition. Are recorded on the recording tracks in a dispersed manner, and the recording condition is obtained by using the average value of the reproduction jitter of only the selected sector.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. DVDR as a specific example of an optical disk
An example in which an AM disk is used to determine a recording pulse condition in the recording / reproducing apparatus will be described.

FIG. 2 shows a DVDRAM disk (capacity 4.
7 GB type) is shown in a simplified form. The recording track in the user area of the disk is divided into 35 zones in the radial direction, and one round of the track in each zone is further divided into an integer number of sectors. It is an increasing format. For example, the innermost zone is zone 0 and one round is divided into 25 sectors, and the outermost zone is zone 34 and one round is divided into 59 sectors. Each zone has 1568 recording tracks. Further inside the 0th zone, there is an area called a drive test zone that can be used by the disk recording / reproducing apparatus to determine recording power and recording pulse conditions. It has become. In the present embodiment, it is assumed that test recording and reproduction are performed using the drive test zone.

FIG. 3 is a block diagram of an optical disk recording / reproducing apparatus commonly used in the first and second embodiments. In FIG. 3, reference numeral 1 denotes an optical disk of the DVDRAM format, 2 denotes a motor for rotating the optical disk 1, and 3 denotes an optical head for irradiating a drive test zone of the optical disk 1 with a laser beam and recording and reproducing signals. Reference numeral 5 denotes the whole recording means, in which 6 is a random signal generating means for generating a random signal for base recording, and 7 is 6T.
(T is one cycle of the recording clock) 6 to generate a single signal
T single signal generating means 8 is a test pattern generating means for generating a pattern for obtaining a recording pulse condition. The test pattern will be described later. Reference numeral 9 denotes switch means for switching the signals generated by the above 6 to 8; 10 denotes recording pulse generation means for converting the signal selected by the switch means 9 into a multi-pulse to convert it into a laser drive current 12; Recording pulse condition setting means for setting the recording pulse conditions of the recording pulse generating means 10 based on the output of the averaging means.

The laser drive current 12 is supplied to the optical head 3 and performs recording on the optical disk 1. Numeral 14 denotes a sector synchronizing means for detecting a break (ID) of a sector from the reproduction signal 13 output from the optical head 3 and generating a sector synchronizing signal 15 of the apparatus. The sector synchronizing means 14 controls both during recording and during reproduction. Works with Reference numeral 16 denotes a reproduction jitter measuring means for detecting a reproduction jitter 17 for each sector of the reproduction signal 13, and 18 compares the reproduction jitter 17 for each sector with a predetermined value 1 to obtain a reproduction jitter of a sector where the reproduction jitter 17 is smaller than the predetermined value 1. 1
9 is a reproduction sector storage unit that outputs 9 and outputs the number 20 of sectors where the reproduction jitter 17 is smaller than the predetermined value 1 and stores the number of the sector where the reproduction jitter 17 is smaller than the predetermined value 1. Condition 1 in which the reproduction jitter 17 is smaller than the predetermined value 1
Is defined. Reference numeral 21 denotes reproduction jitter averaging means for obtaining, for each recording condition, an average value of the reproduction jitter of the sectors satisfying the condition 1 and recorded under the same recording conditions. Reference numeral 22 denotes a track that replaces the recording track of the drive test zone where the optical head 3 performs recording and reproduction when the number of sectors 20 that satisfies the condition 1 is compared with the predetermined value 2 and the number of sectors 20 is not more than the predetermined value 2. It is a jump means. A condition in which the number of sectors satisfying the condition 1 is equal to or more than a predetermined value 2 is defined as a condition 2.

Before performing test recording / reproduction for determining recording pulse conditions using the optical disk recording / reproducing apparatus having the above configuration, recording tracks and sectors used in test recording / reproduction are sufficient and sufficient to determine recording pulse conditions. Embodiment 1 shows an example of inspecting and selecting whether or not re-characteristics are provided.
An example in which the recording pulse condition is efficiently obtained using the sector selected by the inspection will be described as a second embodiment.

(Embodiment 1) In this embodiment, in order to check the characteristics of each sector of a sector-divided recording track using the same criterion, the same signal is recorded in each sector with a constant recording condition. Then, the jitter of a signal reproduced from each sector is measured, and a recording track and a sector suitable for test recording and reproduction are selected. The operation of the optical disk recording / reproducing apparatus shown in FIG. 3 will be described with reference to the flowchart shown in FIG.

First, a random signal is base-recorded in all sectors of one track. For this purpose, in FIG. 3, the random signal output from the random signal generation means 6 passes through the switch means 9 and passes through the recording pulse generation means 1.
At 0, the current is converted into a laser drive current 12 and is recorded on a recording track (drive test zone) of the optical disk 1 by the optical head 3. At this time, the recording pulse condition setting means performs the same setting for the recording pulse generation means for all the sectors so that the same recording can be performed for all the sectors of the recording track for test recording.

Next, a single 6T signal is overwritten on the same track. Therefore, in FIG.
The 6T single signal output from the single signal generating means 7 is converted into a laser drive current 12 by the recording pulse generating means 10 through the switch means 9 and is recorded by the optical head 3 on the recording track where the random signal is recorded. Overwritten on top. The 6T single signal is a signal in which a 6T mark and a 6T space are alternately repeated, where T is the length of one cycle of the recording clock.

In the inspection according to the present embodiment, recording is performed at a stage where the recording compensation condition (recording pulse condition) has not yet been determined, so that the recording compensation condition is hardly affected and relatively stable recording / reproducing characteristics can be obtained. Use a single signal. Further, a single signal having a short inner mark length of the single signal has a large absolute value of the jitter value and is likely to fluctuate under the influence of intersymbol interference. On the other hand, when recording is performed for the same period, the number of edges included in inverse proportion to the length of the mark to be recorded decreases, so that the longer the mark length, the lower the accuracy of the detection jitter.
For the above reasons, of the single signals from 3T to 14T, the present embodiment uses a 6T single signal.

Although the drive test zone is actually composed of a plurality of recording tracks, FIG. 4 is a diagram in which one track in the drive test zone is extracted and drawn. The drive test zone is composed of 25 sectors in one round, and a random signal is under-recorded under the same recording conditions (constant recording pulse conditions and the same power conditions) for all 25 sectors in one track. After that, the 6T single signal is overwritten.

The purpose of recording a random signal first before recording a single signal is to eliminate the influence of the background by overwriting and erasing the data originally recorded on the recording track to be used. When a single signal is directly recorded without recording a random signal underlay, if a different type of signal is originally recorded in each sector, the measured reproduction jitter of each sector may vary. is there. Further, when the underlying recording is DC erased, a single signal is overwritten on an unrecorded track, so that a characteristic defect due to a decrease in the erasing rate of the track cannot be detected.

Next, the same track is reproduced, and the reproduction jitter of each sector is measured. Therefore, in FIG. 3, the reproduced signal 13 of the 6T single signal output from the optical head 3 is shown in FIG.
Then, the reproduction jitter measuring means 16 detects the reproduction jitter 17 for each sector while the sector synchronization means 14 identifies the sector.

FIG. 5 is a graph showing the reproduction jitter of a single 6T signal measured as an example. In FIG. 5, the horizontal axis indicates the sector number of one track round, and the vertical axis indicates the detected jitter value for each sector.

Next, a sector having a jitter smaller than the predetermined value 1, that is, satisfying the condition 1, is selected. For this purpose, in FIG. 3, a sector having a jitter smaller than the predetermined value 1 is selected by the sector storage means 18, the number 20 is output, and the sector number is stored.

Finally, it is determined whether or not the number of selected sectors is smaller than a predetermined value 2, that is, whether or not the condition 2 is satisfied. If not, a track jump is performed to replace a recording track. For this purpose, the track jump means 22 in FIG. 3 compares the number of sectors 20 satisfying the condition 1 with a predetermined value 2, and if the condition 2 is not satisfied, issues a command to the optical head 3 to execute a track jump and perform a sector inspection. Again. If condition 2 is satisfied, the track inspection is not performed and the sector inspection ends.
In order to prevent an infinite loop, the number of track jumps is stored, and while the number of track jumps is smaller than the predetermined value 3, track replacement and sector inspection are repeatedly executed. Interrupts processing as an error.

The specific numerical value of each predetermined value will be described. As a preferable numerical value, the value of the predetermined value 1 is 10%, the value of the predetermined value 2 is 15 and the value of the predetermined value 3 is 16 times. When a 6T single signal is recorded on a track having good characteristics,
Usually, the reproduction jitter value is 8% or less. However, when a defect is present on the track or the characteristics of each sector are deteriorated, a jitter value of 10% or more is detected, so that the quality of the sector can be easily identified. When the jitter value obtained by recording / reproducing a 6T single signal is 10% or less,
If three-fifths (that is, 15) of the 25 sectors are good sectors, detection accuracy can be sufficiently ensured when the recording pulse condition is later determined using this track. If the number of track replacements exceeds 16, the error processing is desirably performed because the failure of the apparatus itself is considered to be a cause other than the deterioration of the recording track.

In the example shown in FIG. 5, since a jitter exceeding a predetermined value of 10% is detected in the sector number 3, this sector is regarded as defective, and the operation shifts to an operation for obtaining a recording pulse condition using other sectors. . In this example, track replacement is not performed.

By the above operation, the optical disk recording / reproducing apparatus according to the first embodiment performs recording / reproducing of a single signal with respect to a target recording track, and performs recording / reproducing using the obtained reproduction jitter value for each sector as a criterion. The quality of each track sector can be inspected and identified. Further, even when there are many defective sectors in the recording track, the tracks are replaced and the sector is re-examined, and a sector having good characteristics can be searched. In addition, the stored good sector numbers can be effectively used for reducing test errors in later test recording and reproduction.

(Second Embodiment) In a second embodiment, test recording and reproduction are performed using the recording tracks and sectors selected in the first embodiment, and optimum recording is performed for a combination of a disk and a recording / reproducing apparatus. Explore pulse conditions.
Since the principle of obtaining the recording pulse condition is described in the literature (Japanese Patent Application No. 11-313657), the detailed description is omitted. Here, 8Tm / 6Ts / 4 is used to determine the mark front end pulse condition 5Ts4Tm among the recording pulse conditions.
In the case where test recording and reproduction are performed using a test pattern of a repetitive signal of Tm / 6Ts, a case where an optimum value is searched for by changing five types of mark front end pulse conditions will be described.

The operation of the optical disk recording / reproducing apparatus shown in FIG.
This will be described with reference to the flowchart shown in FIG. In the recording / reproducing operation according to the second embodiment, recording / reproducing is performed on all sectors including a defective sector. On the other hand, when judging a recording pulse condition, a reproducing jitter value of only a good sector excluding a defective sector is determined. Use

First, in order to eliminate the influence of the background by overwriting and erasing the data originally recorded on the recording track to be used, a random signal is base-recorded in all the sectors around one track. For this purpose, in FIG. 3, the random signal output from the random signal generating means 6 passes through the switch means 9, is converted into a laser drive current 12 by the recording pulse generating means 10, and is recorded by the optical head 3 on the recording track of the optical disc 1. (A drive test zone in which one round is composed of 25 sectors).

Next, a test pattern is recorded in five sectors while changing the recording pulse condition for each sector. for that reason,
In FIG. 3, the test pattern output from the test pattern generator 8 is input to the recording pulse generator 10 via the switch 9. At this time, the sector synchronization means 1
The recording pulse condition setting means 11 operates based on the sector synchronizing signal 15 output from the recording section 4 and sequentially sets the recording conditions for the recording pulse generating means 10 for each sector from # 1 to # 5. Thereby, 8Tm / 6Ts / 4Tm / 6Ts
Are converted into five types of laser drive currents 12 having different recording pulse conditions, and the optical head 3 sequentially applies the test patterns to the recording track on which the random signal is recorded for each recording condition. Overwritten by 5 sectors.

FIG. 8 illustrates the relationship between the test pattern and the laser drive current. FIG. 8 shows the rising edge of the boundary between 6Ts and 4Tm in the test pattern and 4Ts.
The time interval from the head position of the mark recording pulse, that is, the waveforms of five types of laser drive currents set under different conditions of the mark front end pulse condition 5Ts4Tm are shown.

Next, the above-described 5-sector recording is repeated five times until all 25 sectors in one round of the recording track are filled. FIG. 1 is a schematic diagram of a recording state in which five sectors of five conditions are repeatedly recorded five times for 25 sectors on one circumference of a recording track.

Next, the same track is reproduced, and the reproduction jitter of each sector is measured. Therefore, in FIG. 3, the reproduced signal 13 of the test pattern output from the optical head 3 is shown in FIG.
Then, the reproduction jitter measuring means 16 detects the reproduction jitter 17 for each sector while the sector synchronization means 14 identifies the sector. FIG. 9A is a graph showing the reproduction jitter of a test pattern measured as an example.

Next, the average value of the jitter for each recording condition is calculated except for the defective sector. For this purpose, the reproduction jitter 17 for each sector passes only the reproduction jitter 19 in the sector storage means 18 based on the sector number stored in advance (satisfies the condition 1 in the first embodiment). As for the reproduction jitter 19, a reproduction jitter averaging means 21 calculates an average value of reproduction jitter of sectors recorded under the same recording conditions. FIG. 9B is a graph showing the average jitter under the same recording conditions. FIG.
In (b), when averaging is performed, the sector number 3
Are indicated by a bold line, and when the calculation is also performed using the value of the sector number 3, the line is indicated by a thin line for comparison. In this embodiment, if the average jitter is obtained using the reproduction jitter value of the sector number 3 without using the information of the stored sector, as shown in a thin line in FIG. Under the condition that the average jitter value is minimized, the value of # 3 becomes large when the value is originally # 3, and # 4 is erroneously determined to be the optimum recording pulse condition. However, in this embodiment, since the average jitter value is calculated excluding the defective sector, a more correct result can be obtained.

Finally, a recording condition that minimizes the average jitter value is selected. Therefore, the recording pulse condition setting means 1
In step 1, the recording pulse condition that minimizes the average jitter value detected by the reproduction jitter averaging means 21 is fixed as a value to be used by the apparatus thereafter. The same procedure is repeated for the other test patterns, and after all the recording pulse conditions have been searched, the process is terminated.

By the above operation, the optical disk recording / reproducing apparatus according to the second embodiment performs recording / reproducing of the test pattern on the inspected recording track and sector, and determines the obtained average jitter value for each recording condition as a criterion. As a result, the optimum value of the recording pulse condition can be searched. In the recording / reproducing method, since the same recording conditions are radially dispersed as shown in FIG. 1, it is necessary to minimize the influence of variations in the characteristics of the optical disc in the circumferential direction when the averaging process is performed. Can be. Further, even if there is a defective sector in the recording track, this is not used in the internal processing, so that the search accuracy of the recording pulse condition can be improved. Therefore, as compared with the case where the averaging process is performed simply by increasing the number of times of recording, an increase in the recording / reproduction time is minimized, and the accuracy is improved.

In the present embodiment, the description has been made using the drive test zone in which the number of sectors in one track is 25. However, the present invention is not limited to this. The user area in the user area where no user data is recorded is recorded. A track or a drive test zone on the outer peripheral side having 59 sectors may be used. In this case, if the test writing of the five types of recording conditions is repeated five or more times, the effect of averaging can be expected. When the track has a number of sectors that cannot be divided by 5, unrecorded sectors of less than 5 sectors may remain. However, in the case where an odd number of recording conditions are provided for a recording track having 25 sectors per circumference of a DVDRAM so that optimum conditions can be easily searched, and the repetition is performed so that no more sectors are left, recording is performed under five conditions. , This is 5
When it is repeated twice, the utilization efficiency of the sector is the best.

[0038]

As described above, according to the optical disk recording / reproducing apparatus of the present invention, in order to reduce the influence of variations in the characteristics of the optical disk and the recording / reproducing apparatus, the recording pulse condition is determined for each disk and apparatus. In, the condition parameters can be obtained with high accuracy in a short time. Therefore, this is effective in improving the performance and reliability of the optical disc recording / reproducing apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a recording track according to a second embodiment.

FIG. 2 is a diagram showing a format of an optical disc in the embodiment.

FIG. 3 is a block diagram of an optical disc recording / reproducing apparatus according to the embodiment;

FIG. 4 is a schematic diagram of a recording track according to the first embodiment.

FIG. 5 is a characteristic diagram showing a measurement example of a reproduction jitter of a single signal.

FIG. 6 is a flowchart showing the operation of the first embodiment.

FIG. 7 is a flowchart showing the operation of the second embodiment.

FIG. 8 is a waveform diagram showing a relationship between a test pattern and a laser drive current.

FIG. 9 is a characteristic diagram showing a measurement example of a reproduction jitter of a test pattern.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical disk 2 Motor 3 Optical head 5 Recording means 6 Random signal generation means 7 6T single signal generation means 8 Test pattern generation means 9 Switch means 10 Recording pulse generation means 11 Recording pulse condition setting means 14 Sector synchronization means 15 Sector synchronization signal 16 Reproduction jitter measurement means 18 Sector storage means 21 Reproduction jitter averaging means 22 Track jump means

Claims (3)

[Claims] 1. A recording means for overwriting a single signal after recording a random signal on a recording track having a plurality of sectors distinguished for each predetermined information amount, and reproducing the recording track on which the single signal is recorded. A read jitter measuring means for measuring a read jitter for each sector; and a recording track is replaced when the number of sectors satisfying the condition 1 where the read jitter is smaller than the predetermined value 1 does not satisfy the condition 2 which is not less than the predetermined value 2. A track jump unit for performing the above-mentioned condition 2; and a sector storage unit for storing the number of a sector which satisfies the condition 1 in the recording track which satisfies the condition 2; An optical disk recording / reproducing apparatus, wherein a sector that satisfies condition 1 is selected and stored. 2. An optical disk recording / reproducing apparatus for performing test recording / reproduction for obtaining recording conditions using a recording track selected by the optical disk recording / reproducing apparatus according to claim 1, wherein N and M are two or more. In a recording track having N × M or more sectors distinguished for each predetermined amount of information, a test pattern is recorded in N sectors while changing the recording condition for each sector, and the N sector recording is performed by M Recording means for repeating the recording pattern, and reproducing a recording track on which the test pattern is recorded,
A reproduction jitter measuring means for measuring a reproduction jitter for each sector; and an average reproduction jitter value of a sector which satisfies the condition 1 according to claim 1 among M sectors recorded under the same recording condition, is calculated by N for each recording condition. Reproducing jitter averaging means for determining the number of sectors, recording the sectors having the same recording condition in a dispersed manner on the recording track, and calculating the recording condition using the average value of the reproducing jitter of only the selected sector. Optical disk recording and playback device. 3. The optical disk recording / reproducing apparatus according to claim 2, wherein N = 5 and M = 5.