JPH0383228A - Optical disk device - Google Patents

Abstract

PURPOSE:To obtain the optical disk device with high reliability by providing an information read means, a write failure detection means and a rewrite means. CONSTITUTION:When the writing of information terminates, a control circuit 14 controls laser light and irradiates a recording track. A reproduction signal from a tracking detector 8 is binarized in a video circuit 19. When there is interruption in CPU from a recording abnormality detection circuit 30, namely, when the abnormal fluctuation of an envelope signal is detected, information is rewritten into the exchange area of the optical disk 1. When written information cannot accurately be reproduced, and when there are much errors, an exchange processing is executed. Thus, information which comes to be a write failure owing to a cause except for the deflection of focus can be interchanged and reliability improves.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a destination disk device having a replacement processing function for rewriting information that has been determined to be a write failure, for example.

(Prior Art) As is well known, optical disc devices have been put into practical use that write (record) or reproduce information by spot-irradiating an information track of an optical disc with a laser beam.

Some optical disk devices of this type include a replacement processing function for rewriting information that has been determined to be a write failure. In other words, the lead-after
The information written by the write operation is reproduced, and information that cannot be reproduced correctly is re-recorded, for example, in another area. Generally, the decision as to whether or not to perform this replacement process is determined based on the reading rate (error rate) of information read by read-after-write operations.

However, if foreign matter or scratches are present on the recording surface of the optical disc, the laser beam may be blocked or the focus may be temporarily shifted. For this reason, recording bits are insufficiently formed for information recorded in or near areas to which foreign matter or scratches are attached. Therefore, the amplitude of the reproduced signal obtained when reproducing information becomes small. If the amplitude of the reproduced signal is at the very edge of the binarization level, the information may or may not be reproduced depending on the situation. The problem with such unstable written information is that if it happens to be correctly reproduced by a read-after-write operation, replacement processing is not performed even though there is a writing failure.

(Problem to be Solved by the Invention) As described above, in an optical disk device equipped with a conventional replacement processing function, if information in an unstable writing state is accidentally reproduced correctly by a read-after-write operation, , despite the write failure.
There was a drawback that replacement processing was not performed.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a highly reliable optical disc device that can reliably replace information whose written state is unstable through replacement processing.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the optical disc device of the present invention records or records information by irradiating a recording track of an optical disc with a spot light. In a device that performs reproduction, following the completion of recording, a succession means reads out the information written on the recording track, and the information is written from a saturation line signal of a reproduction signal obtained when the information is read by the succession means. It is comprised of a detection means for detecting a defect, and a rewriting means for rewriting the information when a writing defect is detected by the detection means.

(Operation) This invention enables information recorded in an unstable state to be easily detected by the above-described means, so that information that has not been written correctly can be replaced by appropriate replacement processing. It is something that will be done.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of an optical disc device of the present invention.

That is, the optical disc 1 is rotated by the motor 2 at, for example, a constant speed. This motor 2 is controlled by a motor control circuit 18.

The optical disc 1 is irradiated with a spot of laser light by an optical head 3, and information is recorded or reproduced by irradiation with this laser light.

The optical head 3 is composed of a movable part and a fixed part. The fixed portion of the optical head 3 is fixed to a drive coil 13 that constitutes a movable portion of a linear motor, and this drive coil 13 is connected to a linear motor control circuit 17.

Further, a permanent magnet (not shown) is arranged at the fixed part of the linear motor. Therefore, when the drive coil 13 is excited by the linear motor control circuit 17, the linear motor is moved in the radial direction of the optical disc 1 (in the horizontal direction in the drawing). Then, as the linear motor moves, the optical head 3 is moved in the radial direction of the optical disc 1.

A linear motor position detector 26 is connected to the linear motor control circuit 17, and by detecting an optical scale 25 provided on the optical head 3, the linear motor position detector 26 detects the optical scale 25 provided on the optical head 3. The position of is now detected.

An objective lens 6 is held in the optical head 3 by a wire suspension (not shown), and the objective lens 6 is movable in the focusing direction (optical axis direction of the lens) by a drive coil 5. The coil 4 allows movement in the tracking direction (direction perpendicular to the optical axis of the lens 6).

On the other hand, laser light generated by the semiconductor laser 9 driven by the laser control circuit 14 is irradiated onto the optical disc 1 via the collimator lens 11a, the half prism 11b1, and the objective lens 6.

The reflected light from the optical disk 1 is guided to the half prism 11c via the objective lens 6 and the half prism llb, and the luminous flux separated by the half prism llc is transmitted via the condenser lens 10 to the position sensor (a pair of An image is formed on a tracking detector (detector) 8 and converted into an electrical signal. Further, the narrow beam separated by the half prism 11c is transmitted through the condensing lens 11d1 and the knife edge 12.
Through the position sensor (a pair of focus detectors)
7, where it is converted into an electrical signal.

The output signal of the tracking detector 8 is supplied to the tracking control circuit 16 via the differential amplifier OP1. A track difference signal (a signal indicating whether the laser beam is positioned on the recording track of the optical disc 1, for example, a differential signal) outputted from the tracking control circuit 16 is supplied to the linear motor control circuit 17 and , is supplied to the drive coil 4 in the tracking direction via the driver 27, thereby controlling the position of the objective lens 6 so that the laser beam follows the recording track on the optical disk 1.

The focus detector 7 outputs a signal related to the focus point of the laser beam, and this signal is supplied to the focusing control circuit 15 via the differential amplifier OP2. The output signal of this focusing control circuit 15 is
The laser beam is supplied to the driving coil 5 in the focusing direction through the driver 28, and thereby the laser beam is directed to the optical disc 1.
The position of the objective lens 6 is controlled so that it is always in just focus at the top.

The laser control circuit 14, the focusing control circuit 15, the tracking control circuit 16, the linear motor control circuit 17, the motor control circuit 18, etc. are connected to an input/output control circuit 31.
It is controlled by a CPU (central processing unit) 23 via 1.

The human output control circuit 31 may be configured, for example, with analog/digital (
The control circuit 14 has A/D) conversion and digital/analog (D/A) conversion functions, etc., as described above.
Focusing control circuit 15, tracking control circuit 1
6. In addition to the linear motor control circuit 17 and the motor control circuit 18, the timing circuit 33 and the host interface circuit 34 exchange information with the CPU 23.

Further, a pass line 35 is connected to the input/output control circuit 31. This pass line 35 has the CPU 2
3.Top: c! A CPU memory 24, the host interface circuit 34, a data buffer 36, an error correction circuit 37, and the like are connected.

The data buffer 36 temporarily stores information to be recorded on the optical disc 1 or information read from the optical disc 1, and the storage address and timing of reading and writing of the information are determined by the CPU 23 and the timing circuit 33. It is now controlled by.

The CPO 23 is configured to perform predetermined operations according to a program stored in the CPU memory 24.

As mentioned above, when focusing servo and tracking servo are performed, the sum signal of the output from the tracking detector 8 reflects the unevenness of the recording pits formed on the recording track of the optical disc 1. There is. Therefore, this sum signal is used as an information reproduction signal, is supplied to one video circuit, and is binarized by this one video circuit.

A binary signal (
The video signal) is sent to the modulation/demodulation circuit 32 and demodulated under the control of the timing circuit 33. Then, it becomes reproduction information and is stored in the data buffer 36.

The playback information stored in the data buffer 36 is transferred to an external host computer (not shown) via the host interface circuit 34. In this way, a normal playback operation is performed.

On the other hand, when recording information on the optical disc 1, the above changes/
The demodulation circuit 32 modulates the information to which an error correction code and the like are added, converts it into a pulse signal, and supplies the pulse signal to the laser control circuit 14. Then, by pulse-lighting the semiconductor laser 9 by this laser control circuit 14,
Recording pits are formed on the recording track of the optical disc 1 according to the above information.

Note that PD is a light receiving element provided near the semiconductor laser 9 to detect the amount of light emitted from the semiconductor laser 9, and the output of this light receiving element PD is supplied to the laser control circuit 14.

Reference numeral 30 denotes a recording abnormality detection circuit, and this recording abnormality detection circuit 30 detects an abnormality in the video circuit during a read-after-write operation, that is, when reading written information upon completion of recording of information. Detecting fluctuations in the saturation line (envelope) signal of the reproduced signal supplied to one of the above CP0
This interrupts 2B. This recording abnormality detection circuit 30 is reset by a reset signal from the CPO 23 supplied via the human output control circuit 31.

FIG. 2 shows the configuration of the recording abnormality detection circuit 30.

This recording abnormality detection circuit 30 includes a reference voltage generation section 30 that generates a reference voltage corresponding to the permissible limit of fluctuation of the saturation line signal.
a1 A comparator 30b that compares the reference voltage from the reference voltage generator 30a with the saturation line signal of the reproduced signal from one of the video circuits.

A flip-flop circuit 30 latches the change in the output of the comparator 30b and interrupts the CPU 2B.
It is composed of c.

That is, the saturation line signal is taken in from the positive input terminal of the comparator 30b and compared with the reference voltage from the reference voltage generation section 30a supplied to the negative input terminal. In this case, as shown in Figure 3(a), for example, if the laser beam is blocked by a foreign object or scratch, the focus of the reproduced signal will be temporarily shifted, resulting in insufficient formation of recording pits. , that part is considered to have a small amplitude. Therefore, as shown in FIG. 3(b), the saturation line signal is changed in accordance with the change in the amplitude of the reproduced signal.

A high level signal as shown in FIG. 3(C) is outputted from the comparator 30b in response to a portion of the saturation line signal in which the fluctuation exceeds the reference voltage indicated by the broken line in the figure. The high level signal from the comparator 30b is latched by the flip-flop circuit 30C, so that a recording abnormality detection signal as shown in FIG. 3(d) is supplied to the interrupt terminal of the CPU 23. .

In this way, when a fluctuation exceeding the permissible limit of the saturation line signal is detected during the read-after-write operation, that is, when it is detected that recording pits are not correctly formed on the recording track, an interrupt is generated in the CPU 23. It has become.

Next, the operation when recording information in the above configuration will be explained.

For example, suppose that information to be recorded is input from the host computer. Then, the information is stored in the data buffer 36 via the host interface circuit 34 under the control of the CPU 23.

Further, the CPU 23 controls the laser control circuit 14, the linear motor control circuit 17, the motor control circuit 18, and the like. Then, the linear motor control circuit 17
Control signal from U23 and linear motor position detector 2
The optical head 3 is controlled based on a position signal from the optical disk 6, and address information on the optical disk 1 is read, so that the optical head 3 corresponds to a target recording track on which information is to be recorded, for example. Further, the focus servo is turned on so that the light from the semiconductor laser 9 that is focused by the objective lens 6 is just in focus with respect to the recording track, and the focus servo is turned on so that the laser light follows the recording track. Tracking servo is turned on.

In this state, the error correction circuit 37 adds an error correction code or the like to the information stored in the data buffer 36. The information to which the error correction code and the like are added is modulated by the modulation/demodulation circuit 32 and then supplied to the laser control circuit 14 as a pulse signal. As a result, the semiconductor laser 9 is pulse-lit, thereby forming irregularities corresponding to information called recording bits on the recording track.

In this manner, when writing of information is completed, a read-after-write operation is performed. That is, the laser control circuit 14 is controlled so that the laser beam 11J necessary for reproduction is irradiated onto the recording track in which the above-mentioned information has been written. Then, the sum signal of the output from the tracking detector 8 obtained by irradiating the recording track with the laser beam, that is, the reproduction signal, is binarized by one video circuit.

In addition, in parallel with this information reproduction operation, the recording abnormality detection circuit 30 detects whether or not a recording abnormality has occurred during the read-after-write operation. Then, when an interrupt is received from the recording abnormality detection circuit 30 to the CPO 23,
In other words, if abnormal fluctuations in the saturation route signal are detected,
For example, information is rewritten in a spare area provided separately from the information recording area of the optical disc 1 in the same manner as described above. Since the information is guaranteed by this replacement process, it is possible to prevent a situation in which the information cannot be reproduced later.

Thereafter, if, for example, no abnormal fluctuation of the saturation line signal is detected, the information reproduced by the read-after-write operation is checked.

As a result of this check, if the information that was supposed to have been written could not be reproduced correctly or if there were a large number of errors, the replacement process described above is performed. As a result, even information that has been written poorly due to factors other than focus fluctuation can be replaced, and higher reliability can be obtained.

As described above, the variation in the saturation line signal of the reproduced signal during the read-after-write operation is detected, and this is added to the condition for whether or not to perform replacement processing.

In other words, information whose recording bits are insufficiently formed due to focus fluctuation during recording is detected by checking the saturation line signal of the reproduced signal obtained during read-after-write operation. . This makes writing unstable information relatively easy.
And it becomes possible to detect it reliably. Therefore, by using this detection result as a condition for whether or not to perform replacement processing, a more reliable optical disc device can be realized.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the invention.

[Effects of the Invention] As detailed above, according to the present invention, information whose writing state is unstable can be reliably replaced by replacement processing (':i) A highly reliable optical disc device can be provided. .

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a block diagram showing an optical disc device, FIG. 2 is a block diagram showing the configuration of a recording abnormality detection circuit, and FIG. 3 is a diagram showing the operation of the recording abnormality detection circuit. FIG. 2 is a diagram shown for explaining. 1... Optical disk, 3... Optical head, 7.8...
・Position sensor, 19...Video circuit, 23...CP
U. 30... Recording abnormality detection circuit, 30a... Reference voltage generation section, 30b... Comparator, 30C... Flip-flop circuit.

Claims (1)

[Scope of Claims] In an optical disc device that records or reproduces information by irradiating a spot light onto a recording track of an optical disc, there is provided a reading method that reads information written on the recording track upon completion of recording. means for detecting a writing failure of the information from a saturation line signal of a reproduced signal obtained when reading the information by the reading means; and rewriting the information when the writing failure is detected by the detection means. What is claimed is: 1. An optical disc device comprising: rewriting means for performing the following steps.