JPH06274922A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain a device capable of making it hardly influenced by the environment of temperature and humidity or the like and selecting an optimal power by measuring the upper limit threshold value of the recording power of each disk while considering the variation of a disk characteristic, and searching the optimal recording output of a semiconductor laser from the value. CONSTITUTION:A 3T pattern being the maximum recording frequency is recorded at the arbitrary position of the recording face of a disk 1 by an arbitrary recording power. Next, the recording part is read, the amplitude value of a data signal is measured, and an amplitude value A is obtained. Then, a 8T pattern being the minimum frequency is recorded at the same part by the same recording power as that at the time of recording the maximum recording frequency, the recording part is read, and the amplitude value B of the data signal is obtained. The rate B/A of the amplitude of those data signals is used as a resolution at 5.0mW, and when the resolution is more than 40%, the resolution is searched again. The optimal power is 1.5mW less than the upper limit threshold value at the resolution 40%. Therefore, a value obtained by subtracting 1.5mW from a recording power PH obtained from the upper limit threshold measured value is used as the optimal recording output value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording / reproducing apparatus, and more particularly to the structure of an optical information recording / reproducing apparatus.

[0002]

2. Description of the Related Art In recent years, optical information recording / reproducing devices such as optical disk devices and magneto-optical disk devices are being prepared for standardization according to the ISO standard. The characteristics of the disc, which is an information recording medium used in such a device, are subtly different due to differences in the substrate, foil film material, etc., and in order to record information accurately, it depends on the characteristics of each information recording medium. Therefore, it is necessary to optimize the recording power output by the semiconductor laser. Conventionally, Japanese Patent Application No.
No. 252548, when the disc is initialized, the recording output value is gradually increased from a low output, the threshold value of the recordable output value is obtained, and the dust value is determined based on the threshold value. It has been proposed to add a predetermined recording power so as to compensate the recording power attenuation amount due to the above, and to set the obtained recording power value as the optimum recording power. That is, as a method of selecting the optimum recording power, a method of obtaining the lowest power capable of error correction and then adding a constant value from the obtained power value is generally used. Further, a method has also been considered in which an actual power upper and lower limit is measured every few mW to obtain the power with the best error rate.

However, in the former method of selecting the optimum power, the minimum recordable output is obtained, and the optimum power is set by adding a predetermined compensation amount to the minimum output, and the minimum output is measured. However, it was difficult to obtain the optimum power because the measurement values were apt to be affected by the environment such as temperature and humidity. When the optimum power selection method by the latter method is used, the power range to be raised or lowered is equal to or higher than the threshold value, for example,
Since it is necessary to change the power in the range of 7.5 mW to 9 mW (in the case of 1800 rotations), there is a problem that it takes time to select.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is an optical information recording which is not easily affected by the environment such as temperature and humidity and can select the optimum power quickly. An object is to provide a reproducing device.

[0005]

In order to achieve this object, an optical information recording / reproducing apparatus according to the present invention comprises means for recording data on a disc with a predetermined output, means for reading data recorded on the disc, and reading. Means for determining whether the characteristic of the data is a desired value or not, and detecting the upper limit threshold value of the recording power of the laser light emitted from the semiconductor laser, and a certain constant from the upper limit threshold value of the recording power. And means for setting the optimum recording power of the recording power by subtracting the value,
The upper limit threshold value has a resolution of 4 which is the ratio of the maximum recording frequency to the minimum frequency in the read data.
It is characterized in that the power is set to 0% or more or the error rate of the read data is set to a certain standard value.

[0006]

Therefore, the optical information recording / reproducing apparatus according to the present invention measures the recording power upper limit threshold value for each disc in consideration of variations in the characteristics of the disc, and determines the optimum semiconductor laser from the upper limit threshold value. Since the recording output value is obtained, it is fast and is not affected by environmental conditions such as temperature or humidity. That is, of the recording power, the upper limit on the high output side is measured, and the optimum recording output value is calculated by subtracting a predetermined value from the upper limit output value. As compared with the case where the output value is set, it is possible to suppress the occurrence of an error due to the variation of the measured value due to an external factor and to accurately obtain the optimum recording output value.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a block diagram showing the configuration of an optical information recording / reproducing apparatus which is an embodiment of the present invention. This optical information recording / reproducing apparatus includes a motor 2 for rotating a disc 1 which is an information recording medium for recording various data,
A rotation control system 3 for controlling the number of rotations of the motor 2, an optical pickup 4 for irradiating the recording surface of the disc 1 with laser light output from a semiconductor laser, and the optical pickup 4 is moved in the radial direction of the disc 1. An actuator control system 5 and a signal detector 6 for detecting a signal from the optical pickup 4 are provided. Further, a drive controller 7 with a built-in CPU for performing processing for obtaining an optimum recording output value and controlling the entire apparatus, and a drive controller 7
Is a storage area used by the
A memory 8 including M, RAM and the like, and a laser drive circuit 9 for controlling the output of the semiconductor laser provided in the optical pickup 4 according to the optimum output value output from the drive controller 7.

In the information recording / reproducing apparatus having the above structure, when recording information on the disc 1, the rotation control system 3 drives the motor 2 to rotate the disc 1 under the control of the drive controller 7, and The actuator control system 5 moves the optical pickup 4 based on the output of the drive controller 7, irradiates the control track of the disk 1 with laser light, and detects a signal corresponding to the reflected light by the signal detection unit 6 to drive it. Send to controller 7. In addition, the drive controller 7
The optimum recording output value according to the detection signal is output to the laser drive circuit 9, the power of the laser light with which the recording surface of the disk 1 is irradiated is adjusted, and various information is recorded. On the other hand, disk 1
When reproducing the information recorded on the disk, the laser drive circuit 9 is operated by the reproduction output value from the drive controller 7 to irradiate the disk 1 with a laser beam of a predetermined power, and a signal corresponding to the reflected light. Is detected by the signal detection unit 6 to reproduce various information.

As a method of obtaining the optimum value of the power of the laser light emitted from the optical pickup 4 to the disk 1 via the laser drive circuit 9, for example, a method of considering C / N, a method of considering an error rate, and a jitter. , Etc., and FIG. 2 shows the relationship between C / N, error rate, jitter, and power. As is clear from the figure, the power value at which a C / N of a predetermined value or more and the jitter value of a predetermined value or less are slightly narrower than the power value range considering the error rate. However, the power value that becomes the optimum value is set as the optimum power regardless of which factor is taken into consideration. The C / N curve, the jitter curve, and the error rate curve fluctuate due to variations in manufacturing of the disk and variations in the drive of the information recording / reproducing apparatus, but the fluctuation amount is suppressed to about 10 mW by limiting the quality of the disk. is doing.

FIG. 3 shows the fluctuation of the C / N curve and the fluctuation of the optimum power value due to the fluctuation of the disk. As shown in the figure, the C / N curve due to the disc variation fluctuates by about 10 mW, so that the optimum power of the semiconductor laser is also 10 m.
It varies about W. Therefore, in order to detect the disc variation and determine the optimum power value, it is desirable to perform trial writing on the disc and determine the optimum power value based on the result of the trial writing.

Hereinafter, the setting of the threshold and the setting of the optimum recording power in the optical information recording / reproducing apparatus according to the present invention will be described using the case where C / N is taken into consideration. FIG. 4 is a flow chart showing the setting of the upper limit threshold value of the recording power in the present invention,
First, the 3T pattern, which is the maximum recording frequency, is recorded at an arbitrary position on the recording surface of the disc 1 with an arbitrary recording power.
For example, in the case of a 90 mm diameter magneto-optical disk, the recording output value is 5.0 mW and the maximum recording frequency is 2.9 MHz.
An amplitude value A is obtained by recording the T pattern on the disk 1 and then reading the recorded portion and measuring the amplitude value of the data signal. Next, after recording an 8T pattern (1.09 MHz in the case of a 90 mm magneto-optical disk) having the same recording power as that used when recording the maximum recording frequency and the minimum frequency at the same position, reading was performed. Then, the amplitude value B of the data signal is obtained. The ratio B / A of the amplitude values of the detected data signals is set as the resolution at 5.0 mW, and when the resolution is 40% or more, the recording power is changed and the resolution is calculated again by the procedure described above.

In general, the relationship between the resolution and the recording power decreases linearly with the increase of the recording power as shown in FIG. 5. Therefore, when the detected resolution is 40% or more, for example, the recording power is increased. The power is increased by 1.0 mW, the resolution is detected again, and the measurement of the resolution is repeated until the detected resolution becomes 40% or less. Therefore, 40%
The recording power P _H used when the following resolutions are detected is the upper limit threshold value, and the optimum recording power is set based on the upper limit threshold value P _H.

FIG. 6 shows the relationship between the optimum recording power and the upper limit threshold value of the recording power. The optimum recording power is 1.5 mW lower than the upper limit threshold value at the resolution of 40%, and the upper limit threshold value at the resolution of 30%. The power lower by 2.5 mW is the optimum recording power value. Therefore, from the recording power P _H obtained by the above-mentioned upper limit threshold value measurement, 1.5
The value obtained by subtracting mW is the optimum recording output value. In the above description, the upper limit threshold value measurement was set with a resolution of 40%, which is based on the ISO standard that the resolution of the recording characteristics is 40% or more. However, the value is not limited to this value.

FIG. 7 is a flow chart showing another embodiment of setting the upper threshold value of the optical information recording / reproducing apparatus according to the present invention. In the setting of the upper limit threshold value described above, the upper limit threshold value is obtained based on the resolution of the data signal, but in the second embodiment, the upper limit threshold value is obtained based on the error rate and the optimum recording output value is set. It is a thing. First, after recording a data pattern at a high output of, for example, 9 mW at an arbitrary position on the recording surface of the disc 1, the recorded data pattern is read and the error rate is measured. As for the relationship between the error rate and the recording power, as shown in FIG. 8, the error rate is low in the range of the predetermined recording power.
Therefore, gradually reduce the recording power from high output,
For example, the recording power when the error rate becomes 5 × 10 ⁻⁵ or less is set as the upper limit threshold value P _H. On the other hand, the relationship between the upper limit threshold value P _H set based on the error rate and the optimum recording output value is as shown in FIG. 9, because the upper limit threshold value P _H is about 2.5 mW higher than the optimum recording output value. The optimum recording output value can be calculated by subtracting 2.5 mW from the upper limit threshold obtained by the measurement.

In the above description, the deviation between the upper limit threshold value set based on the error rate and the optimum recording output value is 2.5 mW, but it is set in consideration of the life of the laser diode and the like. However, the present invention is not limited to this. Generally, the recording power considering the error rate can be used in a wider power range as the recording power in comparison with the recording power considering C / N or jitter. However, considering the life of the laser diode, Use with low power is preferable, and
Considering the situation that higher power is required at the outer circumference of the disc than at the inner circumference, the usable recording power range is set, and the amount subtracted from the upper limit threshold value and the optimum recording output value in the set recording power range. Should be set.

[0016]

Since the present invention is configured and functions as described above, the threshold value on the high power side is obtained, and the optimum recording output value is calculated from the upper limit threshold value. This is extremely effective in setting the optimum recording output value according to the characteristics of each disk at high speed without being affected by temperature and the like.

[0017]

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an optical information recording / reproducing apparatus that is an embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between C / N, error rate, jitter, and power.

FIG. 3 is a diagram showing a change in a C / N curve and a change in an optimum power value due to a disc variation.

FIG. 4 is a flowchart showing setting of an upper limit threshold value of recording power according to the present invention.

FIG. 5 is a diagram showing a relationship between resolution and recording power.

FIG. 6 is a diagram showing a relationship between an optimum recording power and an upper limit threshold value of the recording power.

FIG. 7 is a flow chart showing another embodiment of setting the upper limit threshold value of the optical information recording / reproducing apparatus according to the present invention.

FIG. 8 is a diagram showing a relationship between an error rate and recording power.

FIG. 9 is a diagram showing a relationship between an upper limit threshold value P _H set based on an error rate and an optimum recording output value.

[Explanation of symbols]

1 ... Disk, 2 ... Motor, 3 ... Rotation control system, 4 ... Optical pickup, 5 ... Actuator control system,
6 ... Signal detection unit, 7 ... Drive controller,
8 ... Memory, 9 ... Laser drive circuit

Claims (3)

[Claims] 1. An optical information recording / reproducing apparatus for recording data on a disc, which is an information recording medium, using a semiconductor laser, and reading and reproducing the data, and means for recording the data on the disc with a predetermined output, A means for reading the data recorded on the disc, a means for determining whether or not the characteristics of the read data have a desired value, and a means for detecting the upper limit threshold value of the recording power of the laser light emitted from the semiconductor laser, An optical information recording / reproducing apparatus comprising: means for setting an optimum recording power of the recording power by subtracting a certain value from the upper limit threshold value of the recording power. 2. The upper limit threshold value of the recording power is set to a power satisfying a resolution of 40% or more, which is a ratio of the maximum recording frequency to the minimum frequency, of the read data. Optical information recording / reproducing device. 3. The optical information recording / reproducing apparatus according to claim 1, wherein a power satisfying a certain standard value of an error rate of the read data is set as an upper threshold value of recording power.