JPH06243511A - Optical disk for inspecting laser output and method for inspecting laser output of optical disk drive using the same - Google Patents

Abstract

PURPOSE:To provide an optical disk which can easily check the abnormality of the laser power of an optical disk drive and can easily pinpoint the cause of troubles, such as recording defect and reproducing defect, and the method for inspecting the laser power of the optical disk drive by using the optical disk. CONSTITUTION:The magneto-optical disk 1 is so formed that its recording sensibility is varied in 5 stages over the ranges R1, R2, R3, R4, R5 in the diametral direction of the magneto-optical disk 1 by changing the film thicknesses of reflection layers 6. The recording sensitivity in the range R3 is set at a level equal to the level of general magneto-optical disks. With the R3 as a reference, the range R1 is set at -30% recording sensitivity, the range R2 at -10%, the range R4 at +1% and the range R5 at +30%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for inspecting an abnormal output of laser light emitted from an optical disk drive to an optical disk.

[0002]

2. Description of the Related Art Optical discs are widely used as large capacity, exchangeable information recording media. A thermal recording system is a system for recording information on this optical disk. In the thermal recording method, usually, a laser beam is irradiated from an optical disk drive to form a light beam spot having a diameter of about 1 μm on the optical disk, and a local temperature of a recording film of the optical disk is raised to physically change the temperature. Record the encoded information signal.

For example, when a magneto-optical disk is used as the optical disk, the temperature of the recording portion of the recording film is raised up to the Curie point temperature (about 200 ° C.), and at the same time, a magnetic field is applied to the recording film so that the recording magnetic domain is changed. By changing the direction (up and down), binary information composed of 0 and 1 signals is recorded. The recorded information signal is reproduced by utilizing the so-called polar Kerr effect, which detects changes in the polarization plane of the laser light reflected at the recording location.

When the information signal is recorded on the optical disk, if the output of the laser light emitted from the optical disk drive (hereinafter, simply referred to as laser power) is lower than the normal level, the signal can be sufficiently written. Since it is not possible, a trouble of defective recording may occur. Also, even if the laser power is normal when recording the information signal, if the laser power decreases when the recorded information signal is reproduced after a certain time has elapsed, the reproduction signal amplitude cannot be obtained sufficiently. May result in poor reproduction. The causes of such a decrease in laser power include, for example, laser deterioration, laser power control circuit abnormality, scattering of laser light due to dirt adhering to the objective lens, and laser beam eclipse due to optical axis shift of the pickup. There is.

On the other hand, although the frequency of occurrence is lower than the decrease in laser power, the laser power may rise above the normal level due to an abnormality in the laser power control circuit or the like. In this case, the recording pits written in the recording film become too large, and adjacent recording pits interfere with each other, which may cause an error when reading the recorded signal.

As a method for inspecting whether the laser power applied to the optical disk is abnormal or not, conventionally, the optical disk drive is disassembled and the optical system is exposed to the outside, and the laser light is emitted from the pickup. , It was common to measure it with a laser power meter.

[0007]

However, in the above-mentioned conventional inspection method, the optical disk drive must be disassembled each time it is inspected, which is very troublesome.
Furthermore, when disassembled, dust or dirt may enter the inside of the drive and adhere to the optical system or the like to cause a new obstacle. Moreover, normally, the user inspects for the abnormality of the laser power when trouble occurs due to the recording failure or the reproduction failure of the information signal. However, the recording / reproduction failure is not limited to the abnormality of the laser power, but other hardware Or it may be caused by various soft causes. Therefore,
Even if a recording / reproducing failure occurs, the cause is not always clarified by the above-mentioned inspection. Therefore, there is a need for a means for inspecting the laser power as quickly as possible and with less effort.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to easily check the abnormality of the laser power of an optical disk drive and to easily find the cause of troubles such as defective recording and defective reproduction. It is an object of the present invention to provide an optical disc that can be used for the above, and a method for inspecting the laser power of an optical disc drive using the optical disc.

[0009]

In order to achieve the above object, the present invention according to claim 1 provides an optical disc in which a recording film is irradiated with a laser beam to record or reproduce information, and the reproduction signal amplitude is maximum. The optical disc for laser output inspection is configured so that the recording sensitivity changes depending on the radial position of the optical disc when the recording laser output value is defined as the recording sensitivity. The invention described in claim 2 is claim 1
Laser output inspection of an optical disk drive characterized by irradiating a laser beam on the optical disk described above by using an optical disk drive to record or reproduce information, and examining the quality of the information to inspect for an abnormal laser output of the optical disk drive. Is the way.

[0010]

According to the structure of the first aspect, when an abnormality occurs in the laser output applied to the optical disc, recording or reproduction at a specific position on the optical disc becomes defective, so that the abnormality occurs in the laser output. You can easily know what happened. Furthermore, it is possible to distinguish whether the laser output has decreased or increased, depending on the position on the optical disk where the recording or reproduction has become defective, and it is easy to pursue the cause of the trouble. According to the inspection method of claim 2, when the optical disk drive is irradiated with laser power from the optical disk drive, if the laser output is abnormal, recording or reproduction of information will be defective.
It is possible to easily inspect the abnormality of the laser output of the optical disc drive.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for inspecting the laser power of a magneto-optical disk drive will be illustrated and described below as an embodiment of the present invention. FIG. 1 is a sectional view showing a schematic configuration of a magneto-optical disk for laser power inspection (hereinafter, simply referred to as a disk) used in the inspection method of this embodiment. In FIG. 1, a disc 1 includes a light-transmissive substrate 2, a dielectric layer 3, a recording layer 4, which is a perpendicular magnetization film, a dielectric layer 5, and a reflective layer 6.
Are sequentially laminated. In this embodiment, the substrate 2
Was used for the dielectric layer 3, SiN for the dielectric layers 3 and 5, TbFeCoCr for the recording layer 4, and AlTi for the reflective layer 6. The line aa ′ in the figure indicates the rotation axis of the magneto-optical disk 1.

The reflective layer 6 is formed so that its film thickness differs in five steps in the radial ranges R1, R2, R3, R4 and R5 of the disk 1. In order to change the film thickness of the reflective layer 6 in this way, when forming the reflective layer 6, four types of inner peripheral masks having different diameters were used, and the film formation was performed five times. That is, the first film formation was performed without using the inner peripheral mask, and the layer L1 was formed in the entire area of the disk 1. Next, an inner peripheral mask having a radius of R (radius of the disk supporting portion) + R1 was set on the film formation surface, and the second film formation was performed to form the layer L2 in the range R2 to R5. Similarly, the radius R + R1 + R
2, R + R1 + R2 + R3, R + R1 + R2 + R3 + R
The inner peripheral mask of No. 4 was sequentially set to form layers L3, L4 and L5 in predetermined ranges.

It is generally known that the thicker the film thickness of the reflective layer 6, the larger the heat capacity and the more difficult it is to form recording pits. The recording sensitivity of the disc 1 is controlled by changing the film thickness of the reflective layer 6. be able to. In the present embodiment, the recording sensitivity in the range R3 is set to a level equivalent to that of a general magneto-optical disk, and based on this R3, the range R1 is -30%, the range R2 is -10%, and the range R4 is + 10%. In the range R5, the film thickness of the reflective layer 6 was changed so that the recording sensitivity was + 30%. However, the recording sensitivity referred to here is a recording laser power value at which the reproduction signal amplitude becomes maximum, and a minus sign indicates that the recording sensitivity is good and recording can be performed with low laser power.
On the contrary, if the sign is positive, it means that the recording sensitivity is poor. It is desirable that the amount of change in recording sensitivity is within the range of −50% to + 50%, and it is difficult to detect abnormal laser power outside this range.

A laser power inspection method will be described. An ordinary magneto-optical disk is manufactured so as to have a power margin of ± 20% or more with respect to the laser power of the magneto-optical disk drive. Therefore, when data is written on the disk 1 configured as described above by using a general magneto-optical disk drive, for example, ranges R1, R2,
When writing was possible in R3 and not normally in the ranges R4 and R5, it was found that the laser power of this drive was -10 to -20% lower than the standard value. Data can be written on the magneto-optical disk, but the laser power is considerably low, so it can be determined that maintenance is required in the near future. Further, when writing is possible in the range R1 and writing is not possible in the ranges R2, R3, R4, and R5, the laser power of the drive is -50 to -30% lower than the standard value. It turns out that the disc is not writable.

When inspecting a magneto-optical disk drive using the disk 1 for laser power inspection by the above-mentioned method, the drive sector should not be subjected to the exchange sector processing normally performed when a data write error occurs. It is desirable to use a test program that controls

As described above, according to the inspection method of the present embodiment, the laser power of the magneto-optical disk drive is changed by writing on the disk 1 for laser power inspection in a procedure almost the same as that of a normal magneto-optical disk. You can check for abnormalities. Conventionally, it was necessary to disassemble the magneto-optical disk drive to expose the optical system when checking the laser power, but in the inspection method of the present embodiment, the laser power is adjusted by recording or reproducing data. Since the abnormality is identified, the disassembling work of the device is not necessary and the inspection can be performed easily and quickly. Further, it is assumed that the cause of the data writing / reading failure is not only the laser power abnormality but also another hardware or software failure, but if the inspection method of this embodiment is used, At least it will be immediately known whether there is an abnormality in the laser power,
It is easy to investigate the cause of data write / read failure. On the other hand, by regularly performing the write test of the magneto-optical disk drive by the inspection method of the present embodiment, troubles can be prevented and the reliability of data recording / reproduction is improved.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and various modifications are possible. For example, if the change in the film thickness of the reflective layer 6 is set in multiple stages, the change in laser power can be examined in more detail. Further, the recording sensitivity can be changed by changing the film thickness of the layers other than the reflective layer 6. Further, the material of the recording layer 4 is changed, or an oxide layer is formed on the surface of the recording layer 4. Alternatively, the recording layer 4 may be composed of a plurality of layers. In the above embodiment,
Although the magneto-optical disk has been described as an example, the present invention can be similarly applied to a phase change optical disk, an organic dye-based optical disk, and the like.

On the other hand, although the optical disk having the structure as described in the above description of the embodiment has been shown to be used for inspecting the laser power at the time of occurrence of an abnormality in the drive or the periodical inspection, it is usually used as an ordinary optical disk. Similarly, it can be used as a recording medium, and the normality / abnormality of data recording / reproduction may be checked during its use, and it can be effectively used as an inspection means with a simple configuration and easy handling. You can

[0019]

As described above, according to the present invention, the recording sensitivity of the optical disc is changed depending on the radial position of the disc (claim 1). It is possible to check whether the output of the laser beam applied to the optical disk is abnormal, depending on whether recording / reproduction is good or bad. By inspecting the laser output of an optical disk drive using this optical disk (claim 2), it is possible to use a normal optical disk without requiring troublesome work such as disassembling the drive as in the conventional case. With the same procedure, the laser output can be checked easily and quickly. Further, as the cause of the recording failure and the reproduction failure, it is assumed that there are various obstacles other than the abnormality of the laser output. With the use of the optical disc and the inspection method of the present invention, at least the laser output has an abnormality. Whether or not the recording / reproduction is defective can be easily determined because it can be immediately determined.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of an optical disc used in a laser output inspection method of the present invention.

[Explanation of symbols]

 1 Magneto-optical disk 2 Substrate 3 Dielectric layer 4 Recording layer 5 Dielectric layer 6 Reflective layer

Claims (2)

[Claims] 1. An optical disc in which information is recorded or reproduced by irradiating a recording film with a laser beam, and when a recording laser output value that maximizes a reproduction signal amplitude is defined as a recording sensitivity, it depends on a radial position of the optical disc. An optical disk for laser output inspection, characterized in that the recording sensitivity is changed. 2. The optical disk according to claim 1, wherein an optical disk drive is used to irradiate a laser beam to record or reproduce information, and the quality of the information is checked to check the abnormality of the laser output of the optical disk drive. Laser output inspection method for optical disk drive.