JPH0136165B2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to an optical information recording and reproducing device.
In particular, it has means for detecting the medium state of a recording medium on which additional recording is possible.

Prior Art There have been various non-optical file devices that use magnetic disks, etc., but even in the case of relatively large-capacity magnetic disks, each disk has a capacity of 10 ⁸ to 10 ⁹ bits, so it is difficult to store document images, etc. This is still not sufficient as a large-capacity file, and there has been a desire for an even larger-capacity file system suitable for materials files in libraries and literature files in companies.

In recent years, the development of file systems using optical disks and magneto-optical disks each having a recording capacity of 10 ¹⁰ to 10 ¹¹ bits has progressed, and the possibility of large-capacity file systems has increased.

However, recording thin films such as TeO ₂ for information recording in such optical disks and magneto-optical disks are susceptible to changes over time due to crystallization and oxidation. Therefore, efforts are being made to prevent deterioration of the recording layer by providing a protective layer on the surface of the recording thin film, but currently the lifespan of a disk is still only about 10 years even under the best preservation conditions, and new information can be stored on old disks. The current situation is that it cannot withstand long-term storage for 20 to 50 years, including the addition of additional information. Therefore, it is necessary to quickly transfer the information on a disk to a new disk when the disk begins to deteriorate due to its lifespan or storage in a bad environment. The only way to estimate the lifespan is based on this record, which has the disadvantage that the true state of deterioration of the disk at a certain point in time cannot be determined, and therefore there is a risk that important bibliographic information may deteriorate as is.

Purpose Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks, and to provide an optical information recording and reproducing apparatus for recording information on a recording medium or reproducing information recorded on a recording medium. It is an object of the present invention to provide an information recording and reproducing apparatus that can more reliably preserve recorded information.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an outline of a configuration example of the information recording and reproducing apparatus of the present invention, where 1 is a laser light source, 3 is a beam,
4 collimates the beam 3 (converts it into a parallel beam)
Collimator lens 5 is collimator lens 4.
an optical separator such as a half mirror or a beam splitter placed in the optical path of the beam 3 transmitted through the
7 is a tracking mirror that changes the optical path of the beams 3 and 11 that have passed through the optical separator 5; 7 is an objective lens that focuses the beam reflected by the tracking mirror 6; 8 is a recording medium (disk); 9 is a recording medium 8
10 is a beam spot on the recording surface 9. Further, 14 is a photoelectric detection element (photodetector), and the beam 13 reflected by the recording surface 9 passes through the objective lens 7 again, is reflected by the tracking mirror 6 and the optical separator 5, and is received by the photoelectric detection element 14. ,
Photoelectrically converted. M is a drive motor that rotates the recording medium 8 at a predetermined speed.

The laser light beam emitted from the laser light source 1 is
The recording surface 9 of a rotating recording medium (disc) 8 is irradiated with light through a tracking mirror 6 and an objective lens 7, with the beam focused to a diameter of approximately 1 μm.

Information is written on the disk 8 by intermittent (ON, OFF) of the laser beam, and the recording surface 9 of the disk 8 has a reversal of magnetization direction or a change in reflectance in response to the intermittent laser beam. Information is recorded in the form of changes or pithole formations.

To read information from the disk 8, a laser beam with a weaker output than when writing is sent to the objective lens 7.
The light is focused more narrowly and irradiated onto a specific position on the disk 8, and the change in the reflectance of the reflected light 13 from the recording surface 9 (in the case of a magnetic film, a polarizing plate is used) is detected by the photoelectric detection element 14. .

Figures 2A and 2B show changes over time in the reflectance of the recording medium, including deterioration of the antireflection layer, when a tellurium oxide film (TeO ₂ film) is used as the recording layer on the recording medium 8 shown in Figure 1. show. FIG. 2A shows a case where the reflectance increases due to crystallization, and FIG. 2B shows a case where the reflectance decreases due to oxidation, but which state is shown depends on how the protective layer is provided. Second
In the case of Figure A, the recording layer gradually crystallizes and the reflectance increases as time passes, but this rate of change varies greatly depending on the environmental conditions.

FIG. 3 shows an example of the configuration of the recording medium 8 shown in FIG. For example, it is provided at the outermost circumference or the innermost circumference.

When the disk 8 is light-exchanged, the detection area 16 is scanned by a laser beam before recording or reproduction, and the reflected light from the disk 8 is detected by the photoelectric detection element 14, and the detected value is used to detect the disk 8.
The degree of deterioration is detected, and when the deterioration exceeds a certain level shown by the broken line in FIG. 2A or B, a caution signal is given.

Actually, as shown in FIG.
The output current from 4 is converted into current/voltage by the current/voltage converter 17, and the voltage is further converted to the voltage by the comparator 1.
8, the disc 8 is compared with a reference voltage corresponding to the reflectance at the limit of the usable range, and when the voltage is below the reference voltage, a caution lamp 20 is turned on, and an instruction is given to replace the information recorded on the disc 8 with a new disc. .

Therefore, according to this example, it is possible to always use a normal disk, and the recorded information can be stored safely. Also, the detection area 16 is placed on the disk 8.
Therefore, the influence of the recording state of the disc can be eliminated.

Although this example shows an example in which a deterioration state is detected using a light beam for recording and reproducing information, it is also possible to use a detection optical system that can illuminate a wider area on the surface of the disk 8, for example. Of course, a system may also be used.

FIG. 5 shows another example of the configuration of the detection means of the apparatus of the present invention shown in FIG.

The recording layer of the optical disk 8 shown in FIG. 3 is deposited in a vacuum, but since the recording pit system is very small, 1 to 2 .mu.m, even small particles can cause defective pinholes. Furthermore, once a defective pinhole occurs, the defective pinhole tends to develop into a pit defect at a faster rate than the change over time of the recording layer in a normal state due to a combination of defects such as poor coating of the protective layer. The reflectance of the portion of the recording layer where the pinhole has occurred is approximately 1/3 to 1/10 lower than that of the portion in the normal state. Therefore, in the present example shown in FIG. 5, changes in the reflectance of the optical disk 8 due to such pinholes are detected.

In FIG. 5, 21 is a filter that cuts low frequencies from the output from the current-voltage converter 17, 22 is a comparator that compares the output of the filter 21 with a reference voltage, which will be described later, and 23 counts the number of times the output voltage of the comparator is generated. 24 is a counter that detects the number of revolutions of the disk 8 via an encoder (not shown); 25 is a data setting means for supplying the error number B, which will be described later; 26 is a counter A comparator compares the output A of 23 with the number of errors B from the memory 25 and outputs a caution signal, and 27 is a caution lamp that lights up in response to the caution signal.

After the reflected light from the information recording area 15 or the detection area 16 (see FIG. 3) is photoelectrically converted by the photoelectric detection element 14 and the output current from the photoelectric detection element 14 is converted from current to voltage by the current-voltage converter 17, the filter 21 A comparator 18 compares the low frequency output voltage from the filter 21 with the reference voltage. This reference voltage is set in advance at a value approximately 1.2 to 2 times lower than the voltage due to reflection from the normal state portion of the disk 8, since the reflectance change due to the pinhole is relatively large as described above. Next, a count 23 counts the number of times an output voltage lower than this reference voltage is obtained.

Here, as an example, set the radius of disk 8 to 100
mm, and the average pit spacing is 2 μm, the average number of pits per revolution of the disk is approximately 3×10 ⁵ . Therefore, if the number of revolutions of the disk 8 is detected by the counter 24 via an encoder and, for example, the number of counts up on the counter 23 due to a pinhole during 100 revolutions of the disk 8 measured by the counter 24 is 30, then the assumed error rate is A can be thought of as ^1/106 .

The comparator 26 compares the assumed error rate A calculated by the counter 23 with the error number B corresponding to the limit error rate taking error correction into consideration, and the assumed error rate A is larger than the error number B. If so, the caution lamp 27 is turned on to instruct the user to replace the information recorded on the disk 8 with a new disk.

In the above-mentioned embodiment shown in Figure 4, it is difficult to set the reference voltage due to variations in reflectance due to differences in disks, whereas in this example shown in Figure 5, the influence of variations in reflectance between disks is It has the advantage of being small.

Further, in this example, since the error rate can be checked while reading the recorded information in the recording area 15, it is possible to know the actual state of deterioration of the recording layer in the recording area 15. Furthermore,
This example is particularly effective when there is a possibility that the protective surface is partially distorted, such as when acrylic or the like is used as a protective surface on the surface of the disk 8.
Of course, according to this example, it is also possible to detect a partial area of a disk with a high error rate and make it unusable.

Effects As explained above, according to the present invention, the change in the reflectance of the disk over time is detected, so the recording/reproducing ability of the disk can be detected at all times, thereby ensuring reliable data recording. The effect of enabling storage is obtained.

[Brief explanation of drawings]

FIG. 1 is a front view showing an example of the configuration of the information recording/reproducing apparatus of the present invention, and FIGS.
A graph showing an example of the characteristics of the reflectance change over time of the disk shown in the figure, FIG. 3 is a plan view showing an example of the configuration of the disk shown in the first figure, and FIG. Block diagram showing an example, No. 5
The figure is a block diagram showing another example of the configuration of the detection means of the present apparatus shown in the first figure. DESCRIPTION OF SYMBOLS 1... Laser light source, 3... Beam, 4... Collimator lens, 5... Optical separator, 6... Tracking mirror, 7... Objective lens, 8... Recording medium (optical disk), 9... ...Recording surface, 10...Beam spot, 14...Photoelectric detection element, 15...Information recording area, 16...Detection area, 17...Current voltage converter, 18...Comparator, 20...Caution lamp, 21 ...File, 22...Comparator, 23...Counter, 24...Counter, 25
...Data setting means, 26...Comparator, 2
7...Caution lamp.

Claims (1)

[Scope of Claims] 1. In an information recording and reproducing apparatus that records information on a recording medium or reproduces the information recorded on the recording medium, a light beam is irradiated onto the recording medium to emit information from the recording medium. It is characterized by comprising means for obtaining an output corresponding to either the amount of reflected light or the amount of transmitted light, and determining means for comparing the output from the means with a reference output to determine the state of deterioration of the recording medium. Information recording and reproducing device. 2. The discrimination means includes means for generating the reference output, comparison means for comparing the reference output with an output corresponding to either the amount of reflected light or the amount of transmitted light, and deterioration depending on the output of the comparison means. An information recording and reproducing apparatus according to claim 1, comprising means for outputting a state detection means signal.