JPS6040536A - Optical disk device - Google Patents

Abstract

PURPOSE:To attain the focusing and tracking controls of light beams regardless of the length of record and erasion by shifting the center part of the light beam to the edge part of an erased part together with microvibrations given to the center part in case the erased part is long and discontinuous. CONSTITUTION:The reflected light is not produced any more when a pickup 1 of an optical system reaches a record erased part 11, and therefore a read amplifier 2 has no output. A no-signal detecting circuit 4 detects said no-output state and delivers a signal to an FF circuit 5. Receiving this signal, the circuit 5 gives an indication to a tracking control circuit 8 for offset of the optical axis of a light beam and at the same time delivers a signal to an FF circuit 6. Then the circuit 6 delivers a wobbling indication signal of the light beam to a wobbling control circuit 9. As a result, the center of the optical axis is shifted to a position 13 from a position 12 and the wobbling control is carried out. The light beam is reset to its original state when the pickup 1 reads the information again.

Description

Detailed Description of the Invention (a) Technical Field of the Invention The present invention relates to a write-once optical disc device that optically detects the position of the irregular surface of a disc and records/reproduces information. This article relates to a trunk tracking method for areas where records have been erased.

(b) Background of the Technology Optical disks include read-only optical disks, write-once optical disks, and rewritable optical disks, and the read-only optical disks and write-once optical disks are currently in practical use.

A write-once optical disc focuses a light beam into a minute spot of about 1 pm, and directs this light beam to a recording film to form a hole (focus) and record information. This hole (
The focal point) is approximately 1.0 μm in diameter. When reproducing information, the reflectance of the light beam differs where there are holes (Pip 1~) and where there are none, so the record is read out using this. Furthermore, in order to perform these operations, it is necessary to always keep the focal length of the light beam constant, and this control is based on the light reflected from the optical disk surface. Therefore, if there is a portion where the two reflected lights are not reflected, the focal length of the optical beam cannot be kept constant.

This means that information cannot be recorded/played back.

On the other hand, recently there has been a strong demand for erasing recorded information from the standpoint of protecting the confidentiality of information. but.

Since reflected light cannot be obtained from the erased portion, it is necessary to develop some kind of countermeasure to the above-mentioned requirement in write-once optical disk devices as well.

(C) Prior Art and Problems Even in write-once type optical discs, it is necessary to erase records in order to protect the confidentiality of information and eliminate recording errors during recording (100 errors). However, if records are erased over a long distance, reflected light cannot be obtained.

The focal length of the light beam cannot be kept constant, making it impossible to follow the track.

In conventional write-once optical discs, recording and erasing is not performed at all, or is performed within an extremely short range of control time of the focusing servo mechanism 5, which controls the optical axis tip of the light beam, and the tracking servo mechanism, which performs trunk tracking control. Ta. There are various restrictions when performing within an extremely short range, so
There are other problems such as the recording/erasing control circuit becomes complicated, and since the recording/erasing is not complete, security protection is not perfect.

(d) Purpose of the Invention The object of the present invention is to provide a new optical disc device that eliminates the above-mentioned drawbacks, and in particular, the purpose of the present invention is to provide a new optical disc device that eliminates the above-mentioned drawbacks, and in particular, to improve the focus and tracking of the light beam at the erased portion, regardless of the length of the erased record. The object of the present invention is to realize an optical disk device that can be controlled.

(e) Structure of the Invention The present invention includes a focusing servo mechanism that optically detects the position of a reflective surface of a disk and moves an objective lens so as to always focus on the recording surface.

A write-once optical disk device comprising a tracking servo mechanism that optically detects the track position using a light beam passing through the objective lens, and uses a mirror to follow the movement of the trunk position due to eccentricity of the disk. GJ at the erased portion where recording is continuously erased over the length, the center of the light beam is moved to the end of the erased portion within the control time range of the focusing servo mechanism or the tracking servo mechanism, whichever is shorter. and means for causing the erased portion to follow the track by slightly vibrating the light beam in the track direction and the radial direction of the disk, regardless of the length of recording and erasure. This can be achieved by an optical disk device characterized in that it is possible to control the focus and tracking of the light beam in the recording/erasing area.

(f) Examples of the invention The present invention will be explained below with reference to the drawings.

FIG. 1 shows one embodiment of the optical disk device according to the present invention, and FIG.
The figures each show examples of trajectories of the light beam in the recording/erasing portion of the write-once optical disc according to the present invention.

In the figure, 1 is an optical system pink-up, 2 is a read amplifier, 3 is a signal output detection circuit, 4 is a no-signal detection circuit, 5,
6 is a flip-flop circuit (hereinafter abbreviated as F, F circuit), 7 is a focusing control circuit, 8 is a trunking control circuit, 9 is a wobbling control circuit, 10 is a hole (focus), 1] is a recording/erasing section, 12 is the light beam center point (1),
Reference numeral 13 indicates a light beam center point (2), and 14 indicates a wobbling trajectory.

This embodiment includes an optical system pickup 1 that writes/reads information using a light beam, a read amplifier 2 that amplifies the information read by the optical system pickup 1 so that it can be easily processed in the next circuit, and detects the presence of an information signal. A signal output detection circuit 3 outputs to F and F circuits 6, a no-signal detection circuit 4 detects the absence of an information signal, and a tracking control circuit generates an offset L-instruction signal of the tracking servo by the signal from the no-signal detection circuit 4. F outputs to 8, F circuit 5, F.

When the offset instruction signal is output from the F circuit 5, the wobbling instruction signal is output to the wobbling control circuit 9, and the wobbling instruction signal is turned off by the output signal from the signal output detection circuit 3, and the offset instruction signal from the F and F circuits 5 is output. F, F circuit 6, lead amplifier 2 that also turns off the signal output
A focusing control circuit 7 controls the focus of the light beam generated in the optical system pickup 1 based on information from the optical pickup 1, a focusing control circuit 7 controls the focus of the light beam generated in the optical system pickup 1 based on information from the read amplifier 2,
, a tracking control circuit 8 which offsets the optical axis of the light beam by an offset instruction signal from the F circuit 5 and wobbles the optical axis of the light beam by control from the wobbling control circuit 9; It is composed of a wobbling control circuit 9 that controls wobbling.

The optical system pink-up 1 reads information on an optical disk (not shown), and this information is input to the focusing control circuit 7 and the tracking control circuit 8 via the read amplifier 2, and the information is input from the focusing control circuit 7 and the tracking control circuit 8. Under control, the optical system pickup 1 continues to read information in a compressed manner.

When the optical system pink-up 1 is applied to the recording/erasing section I, no reflected light can be obtained, so no signal is input from the optical system pink-up 1, and the read amplifier 2 becomes in a non-output state. No-signal detection circuit 4 detects the state of the cigarette and sends the signal to F.
, output to the F circuit 5. Upon receiving this signal, the F, F circuit 5 instructs the trunking control circuit 8 to offset the optical axis of the light beam, and also outputs a signal to the F, F circuit 6.

The F, F circuit 6 receives this signal and outputs a light beam wobbling control instruction signal to the wobbling control circuit 9.

On the other hand, the tracking control circuit 8 adjusts the center position of the optical axis of the light beam from the optical axis center position 12 by a distance of 1/2 of the hole (focus) diameter according to the offset instruction signal from the F and F circuits 5.
The wobbling of the light beam is controlled by the signal from the wobbling control circuit 9. The wobbling of the light beam continues until the optical system pink-up 1 reads the information, and when the information is read and the read amplifier 2 outputs a signal, the signal output detection circuit 3 detects the signal and outputs it to the F, FIi'J path 6.

The F and F circuits 6 cancel the wobbling control instruction signal, and also cancel the offset 1 instruction signal to the tracking control circuit 8 via the F and F circuits 5, and return the center position of the optical axis of the light beam to position 12, returning it to its original position. Shift to trunk tracking.

(g) Effects of the Invention According to the invention described above, an optical disk device is capable of controlling focus and tracking at the erased portion regardless of the length of recording and erasing, and is capable of erasing records with reliable confidentiality. It has the effect of providing

[Brief explanation of the drawing]

FIG. 1 shows one embodiment of the optical disk device according to the present invention, and FIG.
The figures each show examples of 1ilL traces of the light beam at the recording/erasing portion on the write-once optical disc according to the present invention. In the figure, 1 is an optical pickup, 2 is a read amplifier, 3 is a signal output detection circuit, 4 is a no-signal detection circuit, 5,
6 is F, F circuit, 7 is a focusing control circuit, 8 is a tracking control circuit, 9 is a wobbling control circuit, 10
11 is a recording/erasing part, 12 is a light beam center point (1), 13 is a light beam center point (2), and 14 is a wobbling trace.

Claims (1)

[Claims] A focusing servo mechanism that optically detects the position of the reflective surface of the disk and moves an objective lens so as to always focus on the recording surface, and a focusing servo mechanism that optically detects the track position using a light beam that passes through the objective lens. The write-once optical disk device is composed of a tracking servo mechanism that uses a mirror to follow the movement of the track position due to the eccentricity of the disk, and in the erased portion where records are continuously erased over a fixed length, the focusing servo means for moving the center of the light beam to the edge of the erased portion within a control time range of either the tracking servo mechanism or the tracking servo mechanism, whichever is shorter; 1. An optical disk device comprising means for causing the erased portion to follow the track by slightly vibrating the erased portion in the direction.