JP2592086B2 - Recording sensitivity correction method for recording media - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a recording sensitivity correction method for optimizing data recording on a recording medium such as an optical disk.

[Conventional technology]

Conventionally, for example, JP-A-51-133001 and JP-A-52-133001
As disclosed in Japanese Patent Publication No. 23902, when writing data consisting of a pulse train to an optical disk, recording is performed so that the formed pits have an optimum shape so that data can be read out best. The pulse width and pulse intensity of each pulse of the data to be output (hereinafter referred to as data pulse) are set. This is referred to as data pulse optimization. This data pulse optimization is mainly determined by the data clock of the system, and at the same time, the rotational speed and sensitivity of the optical disk are also taken into consideration. You will be asked to select a sample from the disk and test it.

[Problems to be solved by the invention]

By the way, conventionally, when the pulse width and pulse intensity of a data pulse are determined as described above, these are taken into a drive device, and data is written based on these. Of course, in the CAV (constant angular velocity) method,
The pulse width and pulse intensity of the data pulse are changed according to the position of the optical head in the radial direction of the optical disk. The pulse width and pulse intensity of the data pulse at each position of the optical head are also determined in advance as described above. It has been demanded.

On the other hand, the shape of the pit formed on the optical disk is also affected by the reflectance and sensitivity of the optical disk. These usually have variations, and differ from optical disk to optical disk, or even from the same optical disk, or depending on their respective positions.

For this reason, even if the data pulse is optimized by the above-described conventional method, an optimum pit shape cannot be obtained. Although it is conceivable to set the optimum width and amplitude of the data pulse in consideration of the reflectivity and sensitivity of the optical disk, it is practically impossible to optimize the data pulse for each disk by the conventional method. Impossible.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a recording medium recording sensitivity correction method which solves such a problem and enables optimization of data pulses over the entire recording area of the recording medium.

[Means for solving the problem]

In order to achieve the above-mentioned object, the present invention writes a desired signal every time data is written in a unit section such as a sector,
The shape of the pit or domain formed by reading is determined, and the pulse width and pulse intensity of the data written in the unit section are set according to the determination result so that the pit or domain shape is optimized.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a recording sensitivity correction method for a recording medium according to the present invention, wherein 1 is a pulse width control circuit, 2 is a pulse intensity control circuit, 3 is a laser drive circuit,
4 is an optical head, 5 is a reproduction signal detection circuit, 6 is a jitter amount detection circuit, 7 is a pulse width setting circuit, 8 is an amplitude value detection circuit, 9 is a pulse intensity setting circuit, 10 is an optical disk, and 11 is an input terminal. is there.

In the figure, write data a consisting of a pulse train for one sector inputted from an input terminal 11 is supplied to a pulse width control circuit 1, and each pulse of the write data a is determined by a pulse width setting circuit 7. Set to width. The write data processed in this manner is then supplied to the pulse intensity control circuit 2, and each pulse is set to the pulse intensity determined by the pulse width setting circuit 9 and supplied to the laser drive circuit 3. The laser drive circuit 3 sends a drive signal b to the optical head 4 so that the laser beam is intensity-modulated according to the write data and is irradiated on the optical disk 10. As a result, the write data is written to a predetermined sector of the optical disk 10.

When the data writing for one sector is completed, the data just written is read from the optical disk 10 by the optical head 4. The output signal c of the optical head 4 is supplied to a reproduction signal detection circuit 5, and pulse train data corresponding to the formed pit train is obtained. In a conventional drive device, a check is made as to whether or not data has been correctly written in the predetermined sector by using such a pulse train. In this embodiment, the data output from the reproduction signal detection circuit 5 further includes: Are supplied to the jitter amount detection circuit 6 and the amplitude amount detection circuit 8.

The jitter amount detection circuit 6 detects the amount of deviation of the peak of each supplied pulse from the set reference position as the amount of jitter. The pulse width setting circuit 7 is controlled in accordance with the detected amount of jitter, and the pulse width set by the pulse width setting circuit 7 is changed by a predetermined amount in one step in a direction in which the amount of jitter decreases. Further, the amplitude value detection circuit 8 calculates a difference between the amplitude value of the pulse written and read to the optical disk 10 last time and the amplitude value of the pulse read this time. The pulse intensity setting circuit 9 according to this difference
Is controlled, and the pulse intensity set by the pulse intensity setting circuit 9 is changed by a predetermined amount of one step in a direction in which the amplitude value of the pulse read from the optical disk 10 increases.

As described above, when the pulse width is newly set in the pulse width setting circuit 7 and the pulse intensity is newly set in the pulse intensity setting circuit 9, the write data a to be written to the next sector is input from the input terminal 11, and the pulse width is set. The control circuit 1 and the pulse intensity control circuit 2 process the pulse with the newly set pulse width and pulse intensity and write it to the optical disk 10, which is then read out and reads the jitter amount detection circuit 6 and amplitude value detection circuit 8. And the pulse width and pulse intensity for the write data to be written to the next sector are set.

FIG. 2 schematically shows changes in pulse width and pulse intensity to optimization, and FIG. 2 (a) shows pulse width and pulse intensity with respect to the optimum condition A of the optical disk used. FIG. 3B shows a case where the initial condition B is high when the initial condition B is low. The initial condition B is, for example, obtained by the above-described conventional method and taken into the drive device. In either case of FIGS. 2 (a) and 2 (b), the initial condition B is transmitted to the optical disk 10. With the writing of the data, the pulse width and the pulse intensity approach the optimum condition A step by step, and are set to the optimum condition A by writing the data a small number of times. Note that T is a period required for writing one data.

When the pulse intensity increases, the laser power increases, and the pit formed on the optical disk 10 increases, and the pit becomes longer when viewed in the track direction. In this case, the amount of jitter may change. Further, if the pulse width is changed to reduce the amount of jitter, the amplitude of the reproduced pulse may decrease. As described above, when one of the pulse width and the pulse intensity is changed, both the jitter amount and the amplitude amount may change. For this reason, the pulse width setting circuit 7 and the pulse intensity setting circuit 9 are used.
Control between them is also required. As an example of this control, the amount of one step of the set value in the pulse intensity setting circuit 9 is changed according to the set value of the pulse width setting circuit 7, and
The pulse width setting circuit 7 and the pulse intensity setting circuit 9 change the pulse width setting circuit 7 so that one step of the set value differs in accordance with the setting value of the pulse intensity setting circuit 9.
There is a method of weighting the amount of steps.

As described above, the data is actually written, the pit shape based on the data is determined, and the pulse width and pulse intensity of the data to be written are determined based on the determination result. Therefore, the reflectance and sensitivity are determined for each optical disk. Even if there is a difference,
The pit shape can be optimized without being affected by this, and even if the reflectivity or sensitivity varies depending on the position on the same optical disk, the pit shape is not reflected between adjacent sectors or tracks. Since the rate and sensitivity do not differ greatly, the pulse width and pulse intensity of the data to be written are determined by one step based on the determination result of the pit shape based on the data written in the sector immediately before the sector in which the data is written. By making only the change, the pit shape can be optimized in any sector and track.

In this case, the determination of the pit shape based on the data is, for example, to find the average of the shapes of a plurality of pits forming this data. Even if an error occurs, the pulse width and pulse intensity of the next data due to this change only by one step, and the influence of this determination error can be minimized. When writing data to an optical disk, usually, when data is written, it is read immediately and a check is performed to determine whether or not this data has been written correctly, that is, a RAW (read after write) check is performed. The determination of the pit shape can be performed by using the data read for this RAW check, so that the data writing speed is not reduced by the determination of the pit shape.

FIG. 3 is an explanatory view of another embodiment of the recording sensitivity correction method for a recording medium according to the present invention, and shows a part of a track pattern on an optical disk. , 13B are test areas, and 14A, 14B are data write areas.

In the figure, on an optical disk, a prepit is shown for each sector (sector A and sector B are shown here).
12A and 12B are formed, and the test areas 13A and 13B and the data write areas 14A and 1A are formed outside the formation areas of the pre-pits 12A and 1B.
4B.

Now, assuming that data is to be written in sector A, first, a test signal of a predetermined pattern is written in a test area 13A of this sector A to form a pit row, and then this is read out, and is read out according to the embodiment shown in FIG. Similarly, the jitter amount and the amplitude value are detected. Then, the optimum pulse width and pulse intensity are set from these detected values, and the data is written in the data write area 14A.

As described above, when writing data to each sector, first, a pit is formed in the test area to determine its shape, and based on the result of this determination, the pulse width and pulse intensity of the data to be next written to the same sector are set. . In this case, as in the embodiment shown in FIG. 1, the pulse intensity and pulse width are changed by one step in the direction of optimization.

In this embodiment, one beam or two beams may be used for writing data. When writing data with one beam, a test signal is written into the test areas 13A and 13B, and after one rotation of the optical disk, this test signal is read to determine the pit shape, and determine the pulse width and pulse intensity. Further, data is written after the next one rotation. When two beams are used, they are very close to each other, and a test signal is written to a test area by one preceding beam, and at the same time, this test signal is read by the other beam to determine a pit shape, pulse width and pulse width. A determination is made of the intensity and then the writing of data based on this determination is performed by the preceding beam. In the case of one beam, a test signal is written, and after the next rotation, the test signal is read out and the pit shape is determined. Data is written after the next rotation, and the RAW check is written after the next rotation. In order to write data for one sector, the optical disk must be rotated four times, and it takes time to write data. On the other hand, when two beams are used, writing, reading, and writing of test signals can be performed in the same rotation period of the optical disk, and
It is sufficient to rotate the optical disk twice for writing data of one sector together with the rotation for checking. However, when two beams are used, it goes without saying that the data writing means becomes more complicated than when one beam is used.

The embodiments of the present invention have been described above, but the present invention is not limited to these embodiments.

For example, in the above embodiment, the pulse width and the pulse intensity were changed. However, either one of them may be changed. Alternatively, instead of changing these, the total energy of laser focusing may be controlled. The energy may be regulated by optical means such as electronic shutter, polarization effect, diffraction, and vignetting.

Further, in the above embodiment, data or the like is written by forming a pit having a physical shape on the optical disk. However, a recording in which data is written by a domain having no physical shape is performed. It may be a medium (for example, an optical disk or a magneto-optical disk in which a portion irradiated with a laser beam is transparent).

Further, the pulse width and pulse intensity of the data may be set according to the jitter amount detected from the read pit shape and the difference between the amplitude value and the reference value. However, as described above, it is needless to say that it is preferable to change the pulse width and the pulse intensity by one step in consideration of the influence of defects on the recording medium.

〔The invention's effect〕

As described above, according to the present invention, while controlling the energy of the data writing while accurately grasping the characteristics of the recording medium for each data writing, variations in the characteristics of the recording media and Even if the characteristics vary depending on the position on the same recording medium, pits and domains can be formed under optimal recording conditions, and thus data can always be read in a good state.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a recording sensitivity correction method for a recording medium according to the present invention, FIG. 2 is an explanatory view showing a correcting operation in this embodiment, and FIG. 3 is a recording sensitivity of a recording medium according to the present invention. FIG. 11 is an explanatory diagram showing another embodiment of the correction method. 1 ... pulse width control circuit, 2 ... pulse intensity control circuit,
3 laser drive circuit 4 optical head 5 reproduced signal detection circuit 6 jitter amount detection circuit 7 pulse width setting circuit 8 amplitude value detection circuit 9 pulse intensity Setting circuit, 10 optical disk, 11 input terminal.

Claims (4)

(57) [Claims] 1. A system for sequentially writing data consisting of a pulse train for each unit section of a recording medium, wherein the data or the test signal is composed of one or both of a pulse intensity and a pulse width previously standardized in advance in the unit section. After performing writing using the write condition, the written data or the test signal is read from the recording medium to determine the write state, and the write state is determined according to the playback pulse jitter amount or the playback pulse amplitude value that is the determination result. A recording sensitivity correction method for a recording medium, wherein a writing condition comprising one or both of a pulse intensity and a pulse width as a writing condition of the data in a unit section is reset. 2. The recording medium according to claim 1, wherein the unit section is a section in which a recording position on a recording medium can be divided for each unit, and the entire recording area is divided to correspond to the recording position. A recording sensitivity correction method for a recording medium, wherein the recording sensitivity is optimized. 3. A system for sequentially writing data consisting of a pulse train for each unit section of a recording medium, wherein the data or the test signal is obtained for each unit section from one or both of a pulse intensity and a pulse width previously determined in advance. After performing writing using the following write conditions, the written data or the test signal is read from the recording medium to determine the write state, and the read state is determined according to the determined playback pulse jitter amount or playback pulse amplitude value. A recording sensitivity correction method for a recording medium, wherein a writing condition of the data in the unit section is reset by adding or subtracting a unit pulse width or unit pulse intensity as a unit. 4. The recording medium according to claim 3, wherein the unit section is a section that can divide a recording position on a recording medium for each unit, and divides an entire recording area to correspond to the recording position. A recording sensitivity correction method for a recording medium, wherein the recording sensitivity is optimized.