JP3019778B2 - Optical recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for setting an optimum recording intensity of laser light in optical recording for recording information by irradiating a recording medium with laser light.

[0002]

2. Description of the Related Art A technique for recording or reproducing information on a recording medium using a laser beam has already been put to practical use as an optical disk device. One type of rewritable optical disk device is a phase-change optical memory utilizing a reversible state change between crystal and non-crystal. The recording film used for this is in one of an amorphous state and a crystalline state depending on the heating condition and the cooling condition by the laser beam, and the two states are reversible. Since the optical characteristics are different between the amorphous state and the crystalline state, two states are selectively formed in accordance with a signal to be recorded, and the optical characteristic change in this state is read by a laser beam, whereby the recorded state is obtained. Information is being read.

In order to obtain these two states, there has been proposed a method of irradiating a recording film on an optical disk with a laser beam intensity-modulated between two values, a peak value and a bottom value, according to a signal to be recorded. . When the recording film is irradiated with such a laser beam, the portion irradiated with the peak value laser beam is irradiated with the bottom value laser beam in an amorphous state, regardless of the previous state. Part becomes a crystalline state,
Overwriting is performed by a single laser beam.

As a method for obtaining the optimum recording intensity of the laser beam in such an irradiation method, for example, there is a method described in Japanese Patent Application Laid-Open No. 4-141827. In this method, as described in the claims, one of the peak value and the bottom value of the laser beam is fixed,
The other is recorded from a high intensity gradually lower, and a lower limit value for judging the quality of the reproduced result as “good” is obtained, and a margin value is added to the lower limit value to set an optimum recording intensity.

[0005]

As described above, in order to determine the optimum recording intensity of the laser beam by trial writing, a dedicated inspection area for trial writing is provided on the optical disk, and the recording intensity is changed to the inspection area. By recording and reproducing information to determine pass / fail, a recording lower limit value in the inspection area is obtained, and an optimum recording intensity in the inspection area is first obtained based on the recording lower limit value, and user information is obtained from the optimum recording intensity. Is estimated in an area where the data is actually recorded. However, test writing to the inspection area may be performed in a different device or in a different environment (for example, temperature, humidity, power supply voltage of a power line, a battery, or the like). Writing is performed. When the lower recording limit is obtained using such an area, there is a problem that the lower recording limit fluctuates due to the recording intensity of the laser beam previously recorded in the inspection area.

An object of the present invention is to always obtain a fixed lower recording limit regardless of the history of the inspection area.

[0007]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention provides a method of erasing information recorded in an inspection area before inspecting a lower recording limit, or recording information for inspection. Greater than the intensity of the laser light
The information is recorded in advance in the inspection area at an intensity having a certain relationship with the intensity of the laser light to be recorded for the inspection.

Thus, regardless of the history of the inspection area,
It is possible to always obtain a fixed recording lower limit value.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, in optical recording for recording information on a recording medium by irradiating a laser beam, test writing is performed before recording user information, A recording method for setting the intensity of laser light when recording user information based on a result thereof, wherein information is recorded in a region where test writing is performed by using a second recording intensity higher than a first recording intensity for performing test writing. After recording the information, test writing is performed at the first recording intensity, and information is recorded in advance in the inspection area at a recording intensity having a fixed relationship with the intensity of the laser beam to be recorded for the inspection. This has the effect of preventing the recording lower limit from changing due to the history of the inspection area.

According to a second aspect of the present invention, in optical recording for recording information on a recording medium by irradiating a laser beam, test writing is performed before recording user information, and based on the result, A method of setting the intensity of laser light when recording user information by erasing information recorded in a test writing area at a first erasing intensity and then erasing the information at a first erasing intensity lower than the first erasing intensity. The test writing is performed after erasing again at the erasing intensity of 2, and before the test writing is performed, the information recorded in the inspection area is erased in advance, so that the lower recording limit value can be checked. This has the effect that it can be prevented from changing due to the history of the area.

According to a third aspect of the present invention, in the first aspect of the present invention, a test write is performed after erasing information recorded in a test write area, Before performing the trial writing, erase the information of unknown recording intensity recorded in the inspection area in advance,
By recording information in advance at a recording intensity having a fixed relationship with the intensity of the laser light to be recorded for the inspection, the recording lower limit value can be prevented from changing due to the history of the inspection region.

According to a fourth aspect of the present invention, in the first and third aspects, the second recording intensity is equal to the first recording intensity.
The recording lower limit value changes according to the history of the inspection area by recording information in advance in the inspection area at a recording intensity higher than the recording intensity for performing test writing by a constant intensity. Has the effect of being able to prevent the

According to a fifth aspect of the present invention, in the first and third aspects, the second recording intensity is equal to the first recording intensity.
The recording magnification is set to a fixed magnification of 1 time or more and 1.5 times or less.
By recording information at a recording intensity that is higher than the recording intensity at which test writing is performed by a certain ratio, the recording lower limit value can be prevented from changing due to the history of the inspection area.

According to a sixth aspect of the present invention, in the second aspect of the invention, the first erasing intensity is a fixed magnification of not less than 1 and not more than twice the second erasing intensity. By erasing the information recorded in the inspection area twice with different recording intensities before performing the test writing, it is possible to prevent the recording lower limit value from changing according to the history of the inspection area. It has the effect that it can be prevented.

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a schematic configuration diagram of an optical disk recording / reproducing apparatus according to an embodiment of the present invention. In FIG. 1, an optical disk 1 is driven to rotate by a disk motor 2, a recording signal from a recording signal generator 6 is supplied to a laser driving circuit 4 through a switch 5, and is recorded on the optical disk 1 as a recording medium by a recording head 3. . In the laser drive circuit 4, a peak value setting circuit 7 and a bottom value setting circuit 8
, A recording laser beam having specific peak and bottom values is output. The switch 5 interrupts the recording signal in response to a command from the system control 9, and the laser drive circuit 4 outputs a laser beam for erasing at a fixed bottom value.

The signal recorded by the recording head 3 is read by the reproducing head 10, and the state of the reproduced signal read by the reproducing head 10 is determined by the restoration circuit 12 and the comparison circuit 1.
3 is determined by the pass / fail determination circuit 11 comprising: The restoration circuit 12 restores the reproduction signal to the original recording signal, and the comparison circuit 13 compares the restoration signal with the recording signal from the recording signal generator 6, and determines the difference between the two signals, that is, the error amount of the restoration signal. Pass / fail judgment is made based on the magnitude of. This determination result is supplied to the system control 9, and the system control 9 updates the setting values of the peak value setting circuit 7 and the bottom value setting circuit 8 based on this determination result.

FIG. 2 is a flow chart for explaining the test writing operation in the configuration of FIG. 1, FIG. 3 is a schematic diagram showing a state of erasing, and FIG. 4 is a recording intensity when the history of the inspection area is different. FIG. 5 is a diagram showing the relationship between the error and the amount of error in the restored signal, which will be described below with reference to FIGS.

First, the inspection track 14 in the inspection area is searched. Assuming that the lowest erasing intensity that can be surely erased even when the recording sensitivity of the optical disc 1 fluctuates is B0, the bottom value setting circuit 8 interrupts the recording signal from the recording signal generator 6 with the switch 5 and sets the bottom value. By setting the intensity of the recording head to 1.4 × B0.
Outputs a laser beam having a constant intensity of 1.4 × B0 which is not intensity-modulated, and the signal recorded on the inspection track 14 is erased. At this time, the recording pits 15 of the inspection track 14 are erased with a wider width as the output of the laser light is higher. However, if the output is too high, the output becomes excessive near the center of the laser light as shown in FIG. Will be left unerased,
By setting the bottom value to B0 by the bottom value setting circuit 8 to lower the erasing intensity from the previous time and erasing the vicinity of the center of the inspection track 14 again, as shown in FIG. Is erased.

Assuming that the peak value of the recording intensity to be firstly tested is P1 and the bottom value is B1, the cutoff of the recording signal from the recording signal generator 6 is released by the switch 5, and the peak value setting circuit 7 and the bottom value setting The circuit 8 sets the recording intensity of the bottom value to 1.25 × B1 and the recording intensity of the peak value to 1.2.
The recording head 3 outputs a laser beam modulated by a recording signal, and records the recording signal on the inspection track 14. Thereafter, when the bottom value is set to the recording intensity B1 and the peak value is set to the recording intensity P1 by the peak value setting circuit 7 and the bottom value setting circuit 8, the recording head 3 outputs a laser beam modulated by the recording signal. The recording signal is recorded again on the inspection track 14 on which the recording signal has been recorded.

The signal recorded on the inspection track 14 is read by the reproducing head 10, and the read reproduction signal is restored to the original recording signal by the restoration circuit 12. This restoration signal and the recording signal from the recording signal generator 6 are read. Is compared by the comparison circuit 13 and the pass / fail judgment is made based on the magnitude of the error amount of the restored signal. If the pass / fail judgment result is "good", the peak value and the bottom value of the current inspection recording intensities P1 and B1 are decreased by [Delta] P and [Delta] B, respectively. repeat.

If the result of the pass / fail judgment is "No" and the result of the previous pass / fail judgment is also "No", the recording intensity is considered to be too low.
Only by P, the bottom value is increased by 2 × ΔB, and the search after the first search track is repeated until the quality judgment result becomes “good”.

When the result of the pass / fail judgment is "No" and the result of the previous pass / fail judgment is "Good", the previous recording intensity is the lower limit of recording.
The recording intensity multiplied by 1.25 is set as the optimum recording intensity.

As shown in FIG. 4, the recording is performed twice at different recording powers because the recording lower limit value a of A when the recorded signal is recorded on the inspection track 14 which has been erased in advance,
Inspection track 1 on which a signal is recorded with high recording power
In the case of recording at 4, the recording lower limit b of B is greatly different, and the latter B, which can record a signal even if the signal was previously recorded at a high recording power, is considered to be a substantial recording lower limit. Because you can do it.

In the above description, the recording operation of the user information at the optimum recording intensity is omitted because it is not directly related to the present invention. In addition, although the first erasing intensity is set to 1.4 times the second erasing intensity, other magnifications can be similarly applied. However, if the first erasing intensity is too high, it is considered that the recording medium may be damaged or the unerased portion cannot be erased in the second erasing. Therefore, the first erasing intensity is twice or less the second erasing intensity. It is desirable that Similarly, the recording intensity for recording a signal on the inspection track before the inspection is set to 1.25 times the inspection recording intensity, but other magnifications can be similarly applied. However, if the recording intensity for recording the signal on the inspection track before the inspection is too high, it is conceivable that the recording medium may be damaged and the quality judgment may not be “good”. The recording intensity for recording the signal is desirably 1.5 times or less the inspection recording intensity. Furthermore, in the description of the first embodiment, the recording lower limit is obtained after erasing and recording information on the inspection track 14. However, after erasing, the recording lower limit may be obtained without recording information on the inspection track 14. It is also apparent that the case where the recording lower limit value is obtained after recording information on the inspection track 14 without erasing data is within the scope of the present invention.

[0025]

As described above, according to the present invention, it is possible to always detect a constant lower recording limit regardless of the history of the inspection track, and to set the optimum recording intensity to a constant value. The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an optical disc recording / reproducing apparatus according to an embodiment of the present invention;

FIG. 2 is a flowchart for explaining a test writing operation;

FIG. 3 is a schematic diagram showing the state of the erasure.

FIG. 4 is a diagram showing the relationship between the recording intensity and the amount of error in the restored signal when the histories of the inspection areas are different.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical disk 2 Disk motor 3 Recording head 4 Laser drive circuit 5 Switch 6 Recording signal generator 7 Peak value setting circuit 8 Bottom value setting circuit 9 System control 10 Reproduction head 11 Pass / fail judgment circuit 12 Restoration circuit 13 Comparison circuit 14 Inspection track 15 Recording pit

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Claims (6)

(57) [Claims] 1. An optical recording system for recording information on a recording medium by irradiating a laser beam with a laser beam for recording user information based on a result of trial writing before recording user information. Recording information in a region where test writing is performed at a second recording intensity higher than the first recording intensity at which test writing is performed, and then performing test writing with the first recording intensity. Recording method for optical recording. 2. An optical recording system for recording information on a recording medium by irradiating a laser beam, wherein a test writing is performed before recording the user information, and a laser beam for recording the user information based on the result. A method of setting the intensity of the information recorded in the test writing area after erasing the information at the first erasing intensity and then erasing the information again at the second erasing intensity lower than the first erasing intensity; A recording method for optical recording, comprising performing trial writing. 3. The test writing is performed after erasing the information recorded in the test writing area.
The recording method of the optical recording according to the above. 4. The optical recording method according to claim 1, wherein the second recording intensity is higher than the first recording intensity by a constant intensity. 5. The optical recording method according to claim 1, wherein the second recording intensity is a constant magnification of not less than 1 and not more than 1.5 times the first recording intensity. . 6. The optical recording method according to claim 2, wherein the first erasing intensity is a fixed magnification not less than 1 and not more than twice the second erasing intensity.