JPH0636285A - Deciding method for optimum recording power and optical disk apparatus - Google Patents

Abstract

PURPOSE:To obtain an optical disk apparatus having high reliability by obtaining a true optimum recording power and recording with the power. CONSTITUTION:An area (test area) for obtaining an optimum recording power is erased, and reference data to be output from a reference data generator 23 is recorded on the test area with recording power Pwn. A focus track controller 11 is controlled by a CPU 22, data recorded with the power Pwn is altered, for example, to a state having a focus offset, and then reproduced. At the time of reproducing the data, a signal detected by a signal detecting optical system is fed through an analog signal processor 24, binarized by a binarizer 25, compared with the reference data generated from the generator 23 by a comparator 26, and number of errors (discordant number) is counted. This is executed by altering the Pwn to obtain a correlation between the recording power and the number of errors.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for determining an optimum recording power in an optical disc device and an optical disc device. For example, it is applied to an optical card.

[0002]

2. Description of the Related Art As a known document describing the prior art according to the present invention, there is, for example, Japanese Patent Application Laid-Open No. 3-46131. "Optical disk control device" proposed in this publication
When recording information on an optical disc, the recording power is obtained in advance so that the information can be recorded correctly. That is, it has a recording power changing means, a reference data storing means, and a comparing means for comparing the reference data and the reproduced data, and the reference data is recorded while changing the recording power, and this is reproduced to obtain the reference data. The optimum recording power is obtained by detecting the non-coincidence condition.

In general, the optimum recording power at the time of recording in the optical disc device varies depending on the external environment (temperature, humidity) and various conditions of the recording medium. For this reason, optimum recording cannot be performed with a constant recording power, and therefore a method such as the above-mentioned Japanese Patent Laid-Open No. 3-46131 has been proposed.

However, the above method has the following drawbacks. For example, when a predetermined number of data (8K bits) is recorded by the above method and the number of errors at the time of reproduction and the recording power are graphed, it becomes as shown in FIG. In this case, since the recording power can be recorded with almost no error at the recording power of 6 mW to 9 mW, the true optimum power cannot be obtained. For this reason, there is a risk that recording will be performed with no margin for changes in various recording conditions due to differences in recording areas, etc., and reliability will be poor. Further, the maximum power of the optical disk device used is limited by the maximum rating of the semiconductor laser used in the optical pickup therein, and in some cases, the recording power of up to 9 mW may be obtained. In this case, it is not even possible to obtain a recording power range with almost no error and perform recording with a medium power.

[0005]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for determining an optimum recording power for determining the true optimum recording power and a highly reliable optical disk device. It was made as.

[0006]

In order to achieve the above object, the present invention provides (1)
In a method of determining the optimum recording power in an optical disk device for collecting light from a semiconductor laser on an optical disk and recording, reproducing or erasing information, a test data generating means and a recording power varying means used for obtaining the optimum recording power. And a reproduction signal confirmation means for confirming the recording state of the recorded data, the test data is recorded while changing the recording power, and the reproduction condition is deteriorated to confirm the recording state by the reproduction signal confirmation means. , Determining the optimum recording power, and (2) gradually deteriorating the reproduction condition, or (3) focusing the light from the semiconductor laser on the optical disc to record and reproduce information. Alternatively, in an optical disc device for erasing, a test data generating means and a recording power varying means used for obtaining an optimum recording power are described. A reproduction signal confirmation means for confirming the recording state of the recorded data and a focus offset addition means, and a focus offset is given to the deterioration of the reproduction condition, or (4) the light from the semiconductor laser is recorded on the optical disc. In an optical disk device for collecting, recording, reproducing or erasing information, a test data generating means and a recording power varying means used for obtaining an optimum recording power, and a reproduction signal confirmation means for confirming a recording state of recorded data. And an inclination means for attaching an optical disk,
It is characterized in that the optical disc is tilted to make the reproduction condition worse. Hereinafter, description will be given based on examples of the present invention.

FIG. 1 is a block diagram for explaining an embodiment of an optical disk device according to the present invention. In the figure, 1 is a fixed optical system, 2 is a semiconductor laser (LD), 3 is a coupling lens, and 4 is a coupling lens. Beam splitter (BS) 5, light emission monitor light receiving element, 6 moving optical system, 7 mirror, 8 objective lens, 9 optical disk, 10 signal detection optical system, 11 focus / track control circuit, 12 focus An actuator, 13 is a track actuator, 14 is a first stage amplifier, 15 is a reproduction power control circuit, 16 is a recording power control circuit, 17 is an LD drive circuit, 18 is a spindle motor control circuit, 19 is a spindle motor, and 20 is a seek motor control circuit. , 21 is a seek motor, 22 is a CPU (central processing unit), 23 is a reference data generation circuit, 24 is an analog signal processing circuit, 5 binarization circuit, 26 is a comparator.

Light emitted from a semiconductor laser (hereinafter referred to as LD) 2 in the fixed optical system 1 is collimated by a coupling lens 3 and emitted by a beam splitter (hereinafter referred to as BS) 4. It is split into light that goes to the monitor light receiving element 5 and the moving optical system 6. The light that has entered the moving optical system 6 is reflected back by the mirror 7, and the objective lens 8
The light is focused on the optical disk 9 by. The light reflected by the optical disk 9 travels in the opposite direction to the objective lens 8, the mirror 7 and the BS 4, and the signal detection optical system 10 detects the servo signal and the reproduction signal. The servo signal is input to the focus / track control circuit 11, and the focus actuator 1
Track servo is realized by moving the focus servo or the track actuator 13 by moving 2.

Further, the light split to the light emission monitor light receiving element 5 side by BS4 is photoelectrically converted by the light emission monitor light receiving element 5 and input to the reproduction power control circuit 15 and the recording power control circuit 16 via the first stage amplifier 14. Each of them is controlled and is used to cause the LD 2 to emit light with a reproducing power or a recording power via the LD drive circuit 17. The optical disc 9 is rotated by a spindle motor 19 controlled by a spindle motor control circuit 18, and the moving optical system 6 is moved by a seek motor 21 controlled by a seek motor control circuit 20 in the radial direction of the optical disc 9. To be made. In addition, each control circuit 11, 15, 16,
The CPUs 17 and 18 are controlled by the CPU 22 to record and reproduce information on the optical disc 9.

Next, the procedure for obtaining the optimum recording power will be described. First, an area (test area) for obtaining the optimum recording power is erased, and the reference data output from the reference data generation circuit 23 is set to a certain recording power Pwn.
Record in the test area with. The focus / track control circuit 11 is controlled by the CPU 22 to change the data recorded with the recording power Pwn to, for example, a state having a focus offset and then reproduce the data.
During data reproduction, the signal detected by the signal detection optical system is passed through the analog signal processing circuit 24 and the binarization circuit 25.
The reference data generated by the reference data generation circuit 23 is compared by the comparator 26, and the number of errors (the number of mismatches) is counted. By executing this while changing Pwn, the correlation between the recording power and the number of errors can be obtained.

Now, reproduction of a signal with a focus offset will be described. Assuming that the reference data is a repeating signal of 0011, 1000, 0101, 0100, and the output signal of the analog signal processing circuit 24 when recorded with the true optimum power and reproduced without the focus offset is the signal a of FIG. It was. Further, a signal when recording is performed with a power weaker than the optimum power and is reproduced without a focus offset is represented by b. When this is binarized, it becomes the signals c and d in FIG. 2, and the signal c is obviously better as the signal quality. However, when detected at the rising edge of the clock synchronized with the read signal, the signal c and the signal d become the signal e and the signal f, respectively, and there is no difference between the signals. For this reason, as shown in FIG. 5, the reproduction can be performed with almost no error with the recording power in a considerably wide range. Note that this is the signal n
The same applies to the case where the optimum power is written with a stronger power like.

Next, considering the optimum recording power and the one written with a power weaker than the optimum recording power, the signals g and h in FIG. 3 are obtained. That is, as compared with the signals a and b in FIG. 2, the rising / falling of the signal becomes dull due to the blurred spot on the optical disc 9, and the amplitude becomes smaller in the short pattern (the repeating portion of 0101 ...). There is. Especially, the one written with weaker than the optimum power,
Since the signal is originally close to the 0 level side and the waveform is distorted, the amplitude is significantly reduced. Therefore, like the signal j, it is not binarized correctly, and the number of errors increases.
In this case, there is a possibility that the clock that should be synchronized with the reproduction signal may not be synchronized, but since the number of errors increases, this is not a problem here. Also, in this example, a binarization method having a fixed threshold value is assumed,
Since the signal amplitude is reduced by defocusing, it can be applied to other binarization circuits regardless of the binarization method.

As described above, by defocusing at the time of reproduction for obtaining the optimum recording power, if the defocusing is not performed, the relationship between the recording power and the error number as shown in FIG. The true optimum power is required.

FIG. 6 is a flow chart for explaining the operation of the central processing unit. First, seek to the test area that is the area for obtaining the optimum recording power (step
1) Then, the test area is erased (step 2). Seek to the test area again (step 3) and set the recording power Pwn (step 4). Next, record the data in the test area (s
Seek to the test area again (step 5) (step 6). Next, defocusing is performed (step 7), test area reproduction and data comparison are performed (step 8), and defocusing is turned off (s
tep9). Next, it is judged whether or not it is finished (step 10),
If it has not ended, the process returns to the step 1, and if it has ended, the optimum recording power is calculated from the recording power Pwn and the number of errors (step 11).

Although the above embodiment has been described by focusing, the same effect can be obtained by tilting the optical disk 9. Further, even if the defocus amount (or the tilt of the optical disk) is constant, if the recording power range with few errors is wide as shown in FIG. 5, the above operation is performed while changing the defocus amount (or the tilt of the optical disk). By carrying out, the true optimum recording power can be obtained.

[0016]

As is apparent from the above description, the present invention has the following effects. (1) According to the first aspect of the present invention, since the reproduction condition is deteriorated to confirm the recording state, the recording power range determined to be recordable is narrowed, so that a more accurate optimum recording power is required and reliability is improved. A high optical disk device can be obtained. (2) In claim 2, since the reproduction condition is deteriorated stepwise, the optimum recording power can be detected surely, and the focus is not defocused due to a sudden offset addition or the tilt of the optical disk. It becomes possible to detect. (3) In claim 3, a circuit and a circuit for removing a focus offset due to an error in assembling a light receiving element for focus detection and a circuit offset are shared, and an offset is used when confirming a recording state. Since it is also possible to add, it is possible to obtain a highly reliable optical disk without increasing the circuit scale. (4) In claim 4, since the reproduction condition is deteriorated by changing the inclination of the optical disc, the optimum recording condition can be detected without the possibility of defocusing.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of an optical disc device according to the present invention.

FIG. 2 is a diagram showing a signal process for reproducing a signal with a focus offset according to the present invention.

FIG. 3 is a diagram showing signal processing in the case of writing with an optimum recording power and a weaker power according to the present invention.

FIG. 4 is a diagram showing the true optimum power according to the present invention.

FIG. 5 is a diagram showing recording power with almost no error according to the present invention.

FIG. 6 is a flowchart for explaining the operation of the central processing unit of the present invention.

[Explanation of symbols]

1 ... Fixed optical system, 2 ... Semiconductor laser (LD), 3 ... Coupling lens, 4 ... Beam splitter (BS), 5 ...
Emission monitor light receiving element, 6 ... Emission monitor light receiving element, 7 ... Mirror, 8 ... Objective lens, 9 ... Optical disk, 10 ... Signal detection optical system, 11 ... Focus / track control circuit, 12
... focus actuator, 13 ... track actuator, 14 ... first stage amplifier, 15 ... reproduction power control circuit, 16 ... recording power control circuit, 17 ... LD drive circuit,
18 ... Spindle motor control circuit, 19 ... Spindle motor, 20 ... Seek motor control circuit, 21 ... Seek motor, 22 ... CPU (central processing unit), 23 ... Reference data generation circuit, 24 ... Analog signal processing circuit, 25 ... 2 Quantization circuit, 26 ... Comparator.

Claims (4)

[Claims] 1. A test data generating means used for obtaining an optimum recording power in an optimum recording power determining method in an optical disk device for condensing light from a semiconductor laser on an optical disk and recording, reproducing or erasing information. A recording power varying means and a reproduction signal confirming means for confirming a recording state of the recorded data, the test data is recorded while changing the recording power, and the reproduction condition is deteriorated by the reproduction signal confirming means. Check the recording status,
A method for determining an optimum recording power, which comprises determining an optimum recording power. 2. The optimum recording power determination method according to claim 1, wherein the reproduction condition is gradually deteriorated. 3. A test data generating means and a recording power varying means used for obtaining an optimum recording power in an optical disk device for condensing light from a semiconductor laser on an optical disk to record, reproduce or erase information. Reproduction signal confirmation means for confirming the recording state of the recorded data,
An optical disk device comprising a focus offset adding means, which is provided with a focus offset for deterioration of reproduction conditions. 4. A test data generating means and a recording power varying means used for obtaining an optimum recording power in an optical disk device for condensing light from a semiconductor laser on an optical disk to record, reproduce or erase information. Reproduction signal confirmation means for confirming the recording state of the recorded data,
An optical disk device comprising an inclining means for attaching an optical disk, and inclining the optical disk when reproduction conditions deteriorate.