JP2000311349A - Optical disk evaluating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable evaluating the degradation of a recording film with respect to all recording areas of an optical disk and to shorten a time required for the evaluation. SOLUTION: In this optical disk evaluating method, a random signal which is generated in a random signal generator 12 is recorded by being lappedly several times in the same area of an optical disk by using an optical disk drive 11. Thereafter, a signal which is generated in a single signal generator 13 and has a prescribed cycle is recorded in the same area, Then, the ratio of the maximum value and the minimum value of the amplitude in the reproduced signal of the recorded single cycle signal or the duty ratio of the reproduced signal is measured, The evaluating of the degradation of a recording film of the disk is performed by deciding whether the ratio or the duty ratio satisfies the criterion of the quality of an optical disk or not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating an optical disc, and more particularly to a method for evaluating a recording film of a recordable / reproducible optical disc.

[0002]

2. Description of the Related Art A general evaluation method for an optical disc is to use a modulation degree of a reproduction signal, an amplitude of a tracking error signal, a reflectivity, and the like as evaluation parameters to determine whether an actually measured value is within a specified range. This is a method of determining. In the method for evaluating a recording / reproducing optical disk, the degree of deterioration of the recording film due to an increase in the number of times of recording is set as one of the evaluation parameters. The evaluation of the deterioration of the recording film is performed by recording a random signal in which a signal having a different cycle appears at random in the same recording area a plurality of times, and reproducing the area in a specific cycle included in the reproduction signal when the area is reproduced. The ratio or the duty ratio between the maximum value and the minimum value of the signal amplitude is measured, and it is determined whether the measured value satisfies the regulation. FIG. 4 shows an example of a schematic diagram of a reproduced signal when such an evaluation method is used.

In FIG. 4, three types of periods are included in a random signal. A, b, and c in FIG. 4 indicate the periods of the respective signals. The vertical axis A indicates the amplitude, and the horizontal axis T indicates the time axis. As shown in FIG.
In the random signal, the appearance of the signal periods a, b, and c has no regularity, and their amplitudes are different.

[0004] Here, a specific signal period is defined as a, and a ratio (a1 / a2) between the maximum value and the minimum value of the amplitude is defined as an evaluation parameter. To measure this evaluation parameter,
It is necessary to extract and process only a portion having a specific signal period a. However, since the appearance of the signal periods a, b, and c has no regularity, the signal period is detected by hardware or software to select a signal of a specific period and measure (a1 / a2). .

[0005]

However, in the above-mentioned conventional configuration, the evaluation result depends on the location where the signal to be measured is recorded, and it is impossible to evaluate all recording areas. There was a problem. Furthermore, since the signal period is detected by hardware or software, a complicated circuit or software is required to actually measure the evaluation parameter (a1 / a2), which increases the cost and decreases the measurement speed. There was a problem.

In the above example, three types of signal periods are included in the random signal.
Since a random signal containing a signal having more than one kind of period is used, there is a problem that the processing means is further complicated. Although the example shown in FIG. 4 is an example of measuring the amplitude, there is a similar problem in the case of measuring the duty ratio.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to make it possible to evaluate the deterioration of a recording film in all recording areas of an optical disk, to reduce the evaluation cost and to increase the measuring speed. And

[0008]

In order to solve the above-mentioned problems, the present invention provides a method for evaluating an optical disk, which comprises the steps of: combining a random signal in which signals having different periods appear randomly and a single-period signal having a specific period. After the random signal is selectively supplied as a recording signal, and a random signal is recorded in the same area of the optical disc a plurality of times, a single-period signal is recorded at least once in the same area, and the amplitude of the reproduced signal is increased. The ratio or duty ratio between the maximum value and the minimum value is measured to determine whether or not the criterion for determining the quality of the recording film of the optical disk is satisfied.

With this configuration, it is not necessary to detect the signal period, and the measurement can be easily performed at low cost.
Further, the measurement can be performed independently of the recording area, and the measurement can be performed quickly and accurately.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION
A random signal in which signals having different periods appear randomly and a single-period signal having a specific period are generated, and either one is selectively supplied as a recording signal, and the random signal is supplied to the same area of the optical disc a plurality of times. After overlapping recording, the single-period signal is recorded at least once in the area, and the ratio or duty ratio between the maximum value and the minimum value of the amplitude of the reproduced signal of the single-period signal is measured, and the recording of the optical disc is performed. This is an evaluation method for an optical disc that determines whether or not the film quality criterion is satisfied. By recording and reproducing a single periodic signal superimposed on a random signal, it is possible to evaluate the deterioration of the recording film in all areas. Has the effect of enabling

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described in detail with reference to FIG.

(Embodiment) In an embodiment of the present invention, after a random signal is recorded a plurality of times, a single period signal is recorded once, and the ratio between the maximum value and the minimum value of the reproduced signal is determined. This is an optical disc evaluation method for measuring and determining the quality of the optical disc.

FIG. 1 is a diagram showing an apparatus configuration for realizing an optical disk evaluation method according to an embodiment of the present invention.
In FIG. 1, an optical disk drive 11 is an optical disk recording / reproducing apparatus on which an optical disk to be evaluated is mounted. The random signal generator 12 is a signal generator that generates a random signal in which signals having different signal periods appear at random and supplies the signal to the optical disk drive 11. The single signal generator 13 is a signal generator that generates a signal having only one of the different periods included in the output signal of the random signal generator 12. In the conventional evaluation, a signal having a different cycle is recorded a plurality of times in the same recording area, and a ratio between a maximum value and a minimum value of the amplitude of a signal having a specific cycle included in the reproduced signal or a duty ratio is measured. This corresponds to a “specific period” in the method.

The selector 14 is a means for selecting which output signal of the random signal generator 12 or the single signal generator 13 is to be supplied to the optical disk drive 11 in accordance with an external command. The reproduction signal 15 is a signal output from the optical disk drive 11. The CPU 16 is a central processing unit that outputs various control commands 17 relating to recording and reproduction of the optical disk drive 11 and the like. Whether the recording signal for the optical disk drive 11 is the output signal of the random signal generator 12,
A control command 18 for determining whether to output the signal from the single signal generator 13 is output to the selector 14.

The procedure of the optical disk evaluation method according to the embodiment of the present invention configured as described above will be described. First, in order to supply the output signal of the random signal generator 12 to the optical disc drive 11, a command for controlling the selector 14 is provided.
18 is output from the CPU 16. Thereafter, the CPU 16 instructs the random number to be recorded a specified number of times in the same area of the optical disk mounted on the optical disk drive 11.
17 is output to execute the recording operation of the output signal of the random signal generator 12. By recording a plurality of signals having different periods randomly in the same area a plurality of times, the recording film of the optical disc is almost uniformly degraded.

Next, a command 18 for controlling the selector 14
The output signal from U16 is supplied from the single signal generator 13 to the optical disk drive 11. Thereafter, the output signal of the single signal generator 13 is recorded at least once in the same area of the optical disc on which the random signal has been recorded, so that
The command 17 is output from the PU 16 to execute the recording operation. By recording signals having a specific cycle in a superimposed manner, a uniform signal can be recorded. If the recording film has not deteriorated, it means that a signal from which a uniform reproduction signal should be obtained has been recorded.

Next, a command 17 is output from the CPU 16 to the optical disk drive 11, and the area in which the above two types of recording operations have been performed is reproduced to obtain a reproduction signal 15. FIG. 2 is a schematic diagram showing a state of the reproduced signal at this time. The signal shown in FIG.
This is a continuous waveform as in FIG. However, as is apparent from FIG. 2, the type of the signal period included therein is only a. The reproduction signal 15 may be directly input to the oscilloscope, and the ratio (a1 / a2) of the maximum value and the minimum value of the amplitude may be directly read and measured, or the maximum value and the minimum value of the envelope may be measured. . Also, it is easy to obtain a measured value by inputting the data to a computer via an analog / digital converter and performing waveform data processing. In FIG. 2, only the amplitude has been described, but the measurement method can be similarly considered for the duty ratio, except that the dimension of measurement is the time axis.

A specific measurement example will be described with reference to FIG. Assume that the signal of the maximum period is 14T. The maximum value of the amplitude of this signal is I14max, and the minimum value of the amplitude is I14min. I14max and I14min are measured, and the value calculated by Expression 1 is obtained and evaluated. (I14max-I14min) / I14max ..... 1

The maximum level of this signal is I14hmax and the minimum level of the signal is I14hmin. I14hmax and I14hmin are measured, and the value calculated by Expression 2 is obtained and evaluated. (I14hmax-I14hmin) / I14hmax Equation 2

If the recording film of the optical disk has not deteriorated, these values should be equal to or higher than a predetermined threshold. If any of them is equal to or smaller than the threshold value, it can be determined that the deterioration characteristic does not satisfy the specified value.

Since a signal having the same period is recorded and reproduced in all recording areas, a signal to be measured can be secured in all recording areas, and measurement can be performed for all recording films.

Although the selector 14 and the optical disk drive 11 are controlled by the CPU 16 in the present embodiment, the CPU 16 may be omitted and the selector 14 and the optical disk drive 11 may be manually set.

As described above, in the embodiment of the present invention,
The evaluation method of the optical disk is such that a random signal is superimposed and recorded a plurality of times, then a single-period signal is recorded once, and the ratio between the maximum value and the minimum value of the amplitude of the reproduced signal of the single-period signal is measured. Since the quality is determined, the optical desk can be easily and quickly evaluated for all recording films.

[0024]

As is apparent from the above description, in the present invention, the method for evaluating an optical disk is performed by generating a random signal in which signals having different periods appear at random and a single-period signal having a specific period. , One of which is selectively supplied as a recording signal, a random signal is recorded in the same area of the optical disc a plurality of times, and then a single-period signal is recorded at least once in the same area, and a reproduction signal of the single-period signal is The ratio of the maximum value and the minimum value of the amplitude or the duty ratio is measured to determine whether or not the quality criterion for the recording film quality of the optical disk is satisfied. The effect is obtained that the deterioration of the recording film can be measured and the evaluation time can be shortened.

[Brief description of the drawings]

FIG. 1 is a diagram showing an apparatus configuration of an optical disc evaluation method according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a reproduction signal waveform when the method for evaluating an optical disc according to the embodiment of the present invention is used;

FIG. 3 shows a maximum value I14 of the amplitude of a reproduced signal waveform when the method of evaluating an optical disk according to the embodiment of the present invention is used.
FIG. 7 is an explanatory diagram of max, a minimum value I14min of the amplitude, a maximum level I14hmax of the periodic signal, and a minimum level I14hmin of the periodic signal;

FIG. 4 is a schematic diagram of a reproduced signal waveform when a conventional evaluation method is used.

[Explanation of symbols]

 11 Optical disk drive 12 Random signal generator 13 Single signal generator 14 Selector 15 Playback signal 16 CPU 17 Various control commands from CPU to optical disk drive 18 Control commands from CPU to selector

Claims (1)

[Claims] 1. A random signal in which signals having different periods appear at random and a single-period signal having a specific period are generated, and either one is selectively supplied as a recording signal, and the random signal is supplied to an optical disk. After overlapping and recording in the same area a plurality of times, the single cycle signal is recorded at least once in the area, and the ratio or duty ratio between the maximum value and the minimum value of the amplitude in the reproduced signal of the single cycle signal is measured. An evaluation method for an optical disk, comprising: determining whether a criterion for determining the quality of a recording film of the optical disk is satisfied.