JPH0573935A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent the abnormality of a focus control and a tracking control, and the obstacle of a recording and reproduction by temporarily restraining an objective lens actuator at the position at the time of detecting a dust or a failure. CONSTITUTION:The focus control and the tracking control are started by a focus control circuit 15 and a tracking control circuit 21, and simultaneously the detecting operation of the dust or the failure is started by a detecting circuit 30 after a proceeding beam is emitted from a semiconductor laser 26 for the preceding beam. The preceding beam from an objective lens 8 is projected on an optical disk 1 in advance of a main beam from an objective lens actuator 7, and the detecting operation of the dust or the failure is performed in advance of the recording and reproducing operation. When the dust or the failure is detected, the operations of the circuits 15 and 21 are stopped, and the objective lens actuator 7 is restrained at the position based on a final control value. Thus, the abnormality of the focus control and the tracking control of the actuator 7 due to the defect such as the dust or crack of the disk 1 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / reproducing device such as an optical disk device and a magneto-optical disk device.

[0002]

2. Description of the Related Art As a conventional optical recording / reproducing apparatus, for example, there is an optical disk apparatus as shown in FIG. In the optical disk device shown in the figure, the optical disk 1 is driven by a disk motor 2 to rotate, and the data of the optical disk 1 is read / written (recorded / reproduced) by an optical head 3. The periphery of this optical disk device is covered by a housing 4, and a disk outlet 5 for inserting and removing the optical disk 1 is formed in the housing 4.

[0003]

However, in such an optical disk device, dust and dust (for example, cigarette smoke, hair, etc.) suspended in the air are included.
However, when the optical disk 1 is taken in and out, it enters from the disk outlet 5 and adheres to the optical disk 1, which not only causes a data read / write error, but also causes an abnormality in the focus control and tracking control of the optical head 3. 3 flies to a completely different track of the optical disc 1 or the focus position of the optical head 3 is deviated, which causes a serious problem in recording and reproducing data. Further, such an optical disk device also causes the same problem if the optical disk 1 has a defect such as a scratch. Then, this invention makes it a subject to solve the said problem.

[0004]

In order to solve the above problems, the present invention has an optical disc for recording data and an objective lens actuator for projecting light onto the optical disc, and the objective lens actuator has focus control and tracking control. Meanwhile, a main optical system for recording and reproducing data on the optical disc, and an objective lens for the main optical system when light or dust is detected on the optical disc by projecting light from the objective lens onto the optical disc prior to the main optical system. And a preceding optical system for temporarily stopping the focus control and tracking control of the actuator to constrain the position of the objective lens actuator.

[0005]

According to the optical recording / reproducing apparatus having such a structure, the main optical system projects the light from the objective lens actuator onto the optical disc to record / reproduce data,
The preceding optical system projects light from the objective lens and detects dust or defects on the optical disc by the reflected light from the optical disc. This detection temporarily stops the focus control and tracking control of the objective lens actuator of the main optical system. To constrain the position of the objective lens actuator. For this reason, the objective lens actuator is temporarily restrained at the position at the time of detecting dust or defects on the optical disc, thereby preventing the focus control and tracking control of the objective lens actuator from being abnormal due to the dust or defects on the optical disc. , It is possible to prevent the objective lens actuator from jumping to a completely different track of the optical disc, and to prevent the focus position of the objective lens actuator from being deviated, thereby preventing the recording and reproducing of the data of the optical disc from being seriously hindered. it can.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing an embodiment of an optical recording / reproducing apparatus according to the present invention. The same parts as those of the conventional example are designated by the same reference numerals. In FIG.
The optical disc 1 is chucked at a predetermined position on the apparatus body (not shown), and the optical disc 1 is driven by a disc motor 2. Reference numeral 7 is an objective lens actuator for projecting light onto the optical disc 1, and the objective lens actuator 7 constitutes a part of a main optical system described later in an optical head (not shown). Reference numeral 8 is also an objective lens actuator that projects light onto the optical disc 1.
Represents a part of a preceding optical system described later in an optical head different from the objective lens actuator 7. The objective lens actuator 7 projects the main beam onto the optical disc 1, and the objective lens actuator 8 projects the preceding beam at a position slightly ahead of the main beam on the same track.

In FIG. 2, reference numeral 10 is a main beam semiconductor laser, and this main beam semiconductor laser 10 emits a main beam to be projected onto the optical disc 1 from the objective lens actuator 7. Main beam semiconductor laser 10 and objective lens actuator 7
Beam splitters 11 and 12 are arranged in the optical path between and. The beam splitters 11 and 12 move the main beam emitted from the main-beam semiconductor laser 10 straight, but the main beam reflected from the optical disk 1 is reflected in the right angle direction and taken out. The main beam reflected from the optical disk 1 and taken out by the beam splitter 11 in the right angle direction is a photoelectric conversion amplifier 14
Is converted into a current value and amplified. The signal output from the photoelectric conversion amplifier 14 is input to the focus control circuit 15, and the focus control circuit 15 inputs the signal to the objective lens actuator 7 via the switching circuit 17 (first switching circuit). A hold circuit 18 is provided in parallel between the focus control circuit 15 and the switching circuit 17, and a signal from the focus control circuit 15 is directly output to the objective lens actuator 7 by the switching circuit 17 performing a switching operation. Or the signal from the hold circuit 18 is output to the objective lens actuator 7.

The main beam reflected from the optical disc 1 and extracted by the beam splitter 12 in the perpendicular direction is
The photoelectric conversion amplifier 20 converts the current value to a current value for amplification. The signal output from the photoelectric conversion amplifier 20 is input to the tracking control circuit 21, and the tracking control circuit 21
Causes a signal to be input to the objective lens actuator 7 via the switching circuit 23 (second switching circuit). A hold circuit 24 is provided in parallel between the tracking control circuit 21 and the switching circuit 23. When the switching circuit 23 performs the switching operation, the signal from the tracking control circuit 21 is directly output to the objective lens actuator 7. Or the signal from the hold circuit 24 is output to the objective lens actuator 7.

Reference numeral 26 is a semiconductor laser for a preceding beam, and this semiconductor laser 26 for a preceding beam emits a preceding beam to be projected onto the optical disk 1 from the objective lens actuator 8. Leading beam semiconductor laser 26
A beam splitter 27 is disposed in the optical path between the objective lens actuator 8 and the objective lens actuator 8. Similar to the beam splitter 11 and the like, the beam splitter 27 carries out an operation in which the preceding beam emitted from the semiconductor laser 26 for the preceding beam travels straight, and the preceding beam reflected from the optical disk 1 is reflected in the perpendicular direction and taken out. The preceding beam reflected from the optical disc 1 and extracted by the beam splitter 27 in the orthogonal direction is converted into a current value by the photoelectric conversion amplifier 29 and amplified. The signal output from the photoelectric conversion amplifier 29 is input to the detection circuit 30, and the detection circuit 30 detects whether or not the optical disc 1 has a defect such as dust or scratch based on the signal from the photoelectric conversion amplifier 29. The detection circuit 30 outputs a signal to the switching control circuit 32 when detecting dust or defects on the optical disk 1, and the switching control circuit 32 outputs a signal to the switching circuits 17 and 23 based on this signal.
Although the objective lens actuator 8 is shown in a simplified manner in FIG. 2 as compared with the objective lens actuator 7, the objective lens actuator 8 is also subjected to focus control and tracking control similarly to the objective lens actuator 7, and a circuit therefor is complicated. It is omitted for the sake of prevention.

The switching circuits 17 and 23 operate so that the signals from the focus control circuit 15 and the tracking control circuit 21 are directly input to the objective lens actuator 7 during the normal data reproducing operation, but the switching control circuit 32.
When the above signal is input from the focus control circuit 1
5 and the signals from the tracking control circuit 21 are blocked, and the switching operation is performed so that the signals from the hold circuits 18 and 24 are input to the objective lens actuator 7. The hold circuits 18 and 24 are switching circuits 17 and 23 of the preliminary focus control circuit 15 and the tracking control circuit 21, respectively.
When the switching circuits 17 and 23 operate as described above while holding the final control value until immediately before the switching operation by the, the subsequent focus control and tracking control operations for the objective lens actuator 7 are stopped, The position of the objective lens actuator 7 is constrained in place by signals from the hold circuits 18 and 24. The preceding beam projected from the objective lens actuator 8 preferably has a large beam spot diameter so that the control operation such as focus control is less likely to be affected by dust and scratches.
Therefore, it is preferable to use the semiconductor laser 26 for the preceding beam having a large wavelength and the objective lens of the objective lens actuator 8 having a small NA (numerical aperture).

Next, the operation of the above embodiment will be described with reference to the flow chart of FIG. When the main beam is emitted from the main beam semiconductor laser 10 and recording or reproduction of data recorded on the optical disc 1 is started, focus control by the focus control circuit 15, tracking control by the tracking control circuit 21, and preceding The preceding beam is emitted from the beam semiconductor laser 26, and the detection operation of dust and defects by the detection circuit 30 is simultaneously started. The preceding beam from the objective lens 8 is projected onto the optical disc 1 prior to the main beam from the objective lens actuator 7, and the detection circuit 30 detects dust and defects on the optical disc 1 prior to the recording or reproducing operation of the objective lens actuator 7. Take action. When the detection circuit 30 detects that the optical disc 1 has a defect such as dust or scratches, the switching control circuit 32 causes the switching circuits 17 and 23 to perform a switching operation so that the focus control circuit 15 and the tracking control circuit 21 can be controlled. The objective lens actuator 7 is stopped, and the objective lens actuator 7 is constrained to its position based on the final control value held by the hold circuits 18 and 24 by the signals from the hold circuits 18 and 24. For this reason, the objective lens actuator 7 is temporarily restrained at the position at the time of detection of a defect such as dust or scratch, so that the focus control or tracking control of the objective lens actuator 7 is caused by the defect of the optical disc 1 such as dust or scratch. To prevent the objective lens actuator 7 from jumping to another track of the optical disc 1 which is completely distant from the optical disc 1 or to prevent the focus position of the objective lens actuator 7 from being deviated. It is possible to prevent the reproduction from being seriously hindered. When a very short predetermined time elapses after the position of the objective lens actuator 7 is constrained, the control operation by the focus control circuit 15 and the tracking control circuit 21 is started again.

By setting the predetermined time during which the objective lens actuator 7 is restrained to be extremely short, it is possible to prevent the continuity of the recording or reproducing of the data on the optical disc 1 from being disturbed, and it is as if the dust is dust. It is possible to continue the operation in the same way as if there were no scratches. Further, even if the preceding beam of the preceding optical system is the optical disc 1
Even if the focus control or the tracking control becomes abnormal due to a defect of the objective lens actuator 8 and the objective lens actuator 8 jumps to a ridiculous place, the detection circuit 30 detects this and outputs a signal to the switching control circuit 32. As a result, the switching control circuit 32 operates in the same manner as the switching circuit 1 described above.
Objective lens actuator 7 by outputting a signal to 7, 23
By restraining the position of, the same effect as above can be obtained.

[0013]

As described above, according to the present invention, the objective lens actuator is temporarily restrained at the position at the time of detection of dust or defect, so that the focus of the objective lens actuator is reduced by the dust or defect of the optical disk. Prevents abnormalities in control and tracking control, prevents the objective lens actuator from jumping to a completely different track on the optical disc, and prevents the focus position of the objective lens actuator from changing, and recording and reproducing optical disc data. It is possible to prevent the trouble from occurring, and it is possible to stably record and reproduce the data. By setting the time for which the objective lens actuator is restrained to be extremely short, it is possible to prevent the continuity of the recording and reproduction of the data on the optical disc from being disturbed, and it is possible to prevent the data from as if there were no dust or defects. It is possible to continue the recording or reproducing operation of.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part showing an embodiment of an optical recording / reproducing apparatus according to the present invention.

FIG. 2 is a circuit diagram of a main optical system having the objective lens actuator 7 and a preceding optical system having the objective lens actuator 8 shown in FIG.

FIG. 3 is a flowchart showing an operation procedure of the embodiment shown in FIGS. 1 and 2.

FIG. 4 is a cross-sectional side view showing a conventional optical recording / reproducing apparatus.

[Explanation of symbols]

 1 Optical Disc 7 Objective Lens Actuator 8 Objective Lens Actuator 10 Main Beam Semiconductor Laser 11, 12, 27 Beam Splitter 14, 20, 29 Photoelectric Conversion Amplifier 15 Focus Control Circuit 17, 23 Switching Circuit 18, 24 Hold Circuit 21 Tracking Control Circuit 26 Leading beam semiconductor laser 30 Detection circuit 32 Switching control circuit

Claims (3)

[Claims] 1. An optical disc for recording data, a main optical system for recording / reproducing data on / from the optical disc, which has an objective lens actuator for projecting light onto the optical disc, while performing focus control and tracking control of the objective lens actuator. When dust or a defect is detected on the optical disc by projecting light onto the optical disc from the objective lens prior to the main optical system, the focus control and tracking control of the objective lens actuator of the main optical system are temporarily stopped to An optical recording / reproducing apparatus comprising: a preceding optical system that constrains the position of an objective lens actuator. 2. The main optical system, a main beam semiconductor laser, a focus control circuit for performing focus control of the objective lens actuator by reflected light from the optical disc, and a focus control circuit immediately before stopping the control operation of the focus control circuit. A hold circuit for holding a final control value, a first switching circuit for switching the focus control circuit or the hold circuit to output a signal to the objective lens actuator, and the objective lens by reflected light from the optical disc. A tracking control circuit for performing tracking control of the actuator, a hold circuit for holding a final control value immediately before the control operation of the tracking control circuit is stopped, and the objective lens actuator by switching to either the tracking control circuit or the hold circuit. To output a signal to The optical recording / reproducing apparatus according to claim 1, further comprising a second switching circuit. 3. The preceding optical system, the semiconductor laser for the preceding beam, a detection circuit for detecting dust and defects on the optical disc by reflected light from the optical disc, and the detection circuit detects dust and defects on the optical disc. And a switching control circuit for outputting a signal to the switching circuit to switch from the focus control circuit and the tracking control circuit to the hold circuit and to output a signal from the hold circuit to the objective lens actuator. The optical recording / reproducing device according to claim 2.