JPH10112045A - Optical disk recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent information recording from being erroneously recorded in the optical disk by surely detecting the track-jumping. SOLUTION: This optical disk recording/reproducing device executing the recording operation while tracing the track of the optical disk 1 by irradiating the optical disk 1 with a laser beams through a lens supported by a lens actuator is provided with a 1st integration means 17 for detecting the lens speed by integrating a driving current of the lens actuator, a 2nd integration means 18 for detecting the displacement of lens from the speed, a means 19 for comparing the specified displacement of lens with the detected displacement of lens, and a control means for stopping the recording operation when the displacement of lens exceeds the prescribed position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk recording / reproducing apparatus for recording information.

[0002]

2. Description of the Related Art In an optical disk recording / reproducing apparatus, when a track servo is performed and a track of the optical disk is traced by a laser spot of the optical head, if the optical disk is damaged, a photodetector of the optical head generates optical noise. Detect. The voltage noise generated at this time is mixed into the tracking servo, and is applied to the lens actuator, causing the lens actuator to swing, thereby causing the track to go off.

In addition, when vibration is applied, a servo voltage is generated to endure an external force, and the servo voltage is applied to the lens actuator to prevent the track from coming off. However, when the allowable value is exceeded, the rack comes off. For this reason, if an out-of-track occurs during recording on the optical disc, the information is destroyed by overwriting the previously recorded information, or the information is recorded when the off-track is recorded in an unrecorded portion. If the optical disc is of a non-rewritable type (write-once type), information cannot be newly recorded. Conventionally, the off-track during recording is detected to prevent these problems.

[0004]

However, when vibration is applied to the tracking servo system, the vibration component of the lens is converted into voltage noise. Noise is converted to voltage noise. These voltage noises appear in the tracking error signal and cause the track to go off. It is necessary to separate the noise into voltage noise that actually causes an off-track or voltage noise that does not lead to an off-track.
For this reason, the voltage level of the voltage noise waveform and the time during which the level is maintained are measured, and when the voltage at or above the specified threshold level is maintained for the specified time or longer, it is determined that an off-track occurs. I was

[0005] In addition, even if the duration is short, off-track may occur, and it is necessary to shorten the duration detection threshold. Since the detection threshold of the duration time was shortened, there was a case where it was determined that the track was off even though the tracking servo was not actually off. In particular, the disk is easily scratched, and a short-duration waveform is apt to be generated due to a defect such as a bubble generated at the time of molding the disk. Some of these waveforms are close to the specified value for determining the duration, and although there is no actual off-track, an over-reaction has occurred and the frequency of interrupting recording has increased. Further, even in a system in which recording data is buffered in a memory, recording processing cannot be performed in response to a recording input, causing an overflow. In the case of vibration (shock) with a high voltage noise level and a short duration, no detection was possible. At that time, overwriting on the already recorded area was caused due to the off track.

[0006]

SUMMARY OF THE INVENTION The present invention relates to an optical disk recording / reproducing apparatus for irradiating an optical disk with a laser from a lens supported by a lens actuator and recording the data while tracing the track of the optical disk. First integrating means for detecting the lens speed, second integrating means for detecting the displacement of the lens from the speed, means for comparing the detected lens displacement with a predetermined lens displacement, An optical disk recording / reproducing apparatus including a control means for stopping recording when the number of recordings exceeds the limit.

[0007]

FIG. 1 is a block diagram showing an embodiment of the apparatus of the present invention. FIG. 1 shows a CD-R as an example.
(CD-Recordable) Disc and a phase change type disc are shown in the case of the laser modulation recording method. In the case of a mini-disc device, a magnetic field modulation method is used. Optical disk 1
Is driven to rotate while the number of rotations is controlled by the spindle motor 3 from the drive circuit 2. The recorded information recorded on the optical disc 1 is read by the optical pickup 4 and the head amplifier 5 detects a tracking error signal. Then, the tracking error signal is input to the phase compensation circuit 6 and the drive circuit 2. The phase compensation circuit 6 and the drive circuit 2 form a servo control circuit, and are controlled by a system controller 7 such as a microcomputer.

The RF signal detected from the head amplifier 5
The signal is input to the decoder 8, and the decoded reproduction signal is output from the main terminal 9. A slide control signal from the drive circuit 2 is applied to the feed motor 10 to move the optical pickup 4. By the position control based on the slide signal, the movement of the optical pickup 4 is controlled to a predetermined track position.

At the time of recording, a recording signal input from an input terminal 11 is encoded by an encoder 12, applied to a laser control circuit 13, and irradiates the optical disc 1 with a laser via an optical pickup 4. The laser control circuit 13
It is controlled by the system controller 7.

Instructions for recording and playback are provided by a playback button 14a, a recording button 14b, and a stop button 1 provided on the operation unit 14.
4c. These commands are detected by the system controller 7. The recording time and operation status of recording and reproduction are displayed on a display unit 15 including a liquid crystal display or the like.

The detection of the amount of displacement of the lens in the optical disk recording / reproducing apparatus having the above configuration will be described below.
First, detection of a drive current of a coil drive type actuator used for tracking control will be described. The detection of the driving current differs depending on the driving method of the actuator. In the case of an actuator driven by a constant voltage drive circuit,
Since the drive current changes depending on the frequency due to the inductance of the coil, the drive current is detected by detecting the voltage across the resistor inserted in series with the coil of the actuator. Then, the amount of displacement of the lens is detected via an integrating circuit including a capacitor and a resistor. In the case of the present invention, the actuator is driven by a constant current drive circuit as shown in FIG. 4, and a voltage at an input terminal proportional to the actuator drive current is used.

FIG. 4 is a circuit diagram showing an embodiment of an actuator driven by a constant current drive circuit. The input resistor (R1) 20, the negative feedback resistor (R2) 21, and the resistor (R
3) 22 are connected in series. The drive current is input to the amplifier 23 via the resistor (R1) 20. The output of the amplifier is connected to the drive coil L24 of the actuator, and is grounded via the resistor (R3) 22. The drive current is the voltage across the resistor (R3) 22 inserted in series with the actuator drive coil L24 or the resistor (R1).
It can be calculated when 20 is detected. In the circuit diagram of FIG. 4, the detection is performed at the input terminal of the resistor (R1) 20 avoiding the resistor (R2) 22 through which a relatively large current flows. At this time, detection can be performed in the same manner as detecting both ends of the resistor (R3) 22.

FIG. 5 is a block diagram showing one embodiment of detecting the amount of lens displacement when an actuator driven by a constant current drive circuit is used. The output of the phase compensation output circuit is controlled by an optical pickup via a constant current drive circuit, and the integration amount is twice performed by an integration circuit to detect the displacement of the lens. As described above, when the drive current of the actuator is detected, it can be detected without being affected by the inductance of the drive coil L24 shown in FIG. Drive coil L
If the inductance of 24 is negligible in practice, it may be replaced with a constant voltage drive circuit.

FIG. 2 is a diagram showing one embodiment of a circuit constituting the lens displacement amount detection of the present invention. FIG. 3 is a waveform diagram at a point in the circuit of FIG. 2 and 3, when the output of the actuator current signal detection circuit 16 in FIG. 1 is input from the input terminal (a) shown in FIG. 2 to the drive current having the waveform shown in FIG. Is integrated by a first integration circuit (17 in FIG. 1) composed of a resistor R and a capacitor C. Then, from the output of the buffer amplifier,
The lens speed signal having the waveform shown in FIG.

Next, the lens speed signal is integrated by a second integration circuit (18 in FIG. 1) composed of C'R 'to obtain a lens displacement signal. FIG. 3C is a waveform diagram of the lens displacement signal. The obtained lens displacement signal is detected by a window comparator or a comparison circuit using an absolute value circuit and a comparator (19 in FIG. 1) to determine whether or not the displacement amount exceeds a predetermined displacement amount. In the above description, the integration circuit is configured by a CR circuit, but may be configured by an active filter.

FIG. 6 is a flowchart showing the processing of the present invention. When the recording button 14b of the operation unit 14 is pressed to start recording the recording signal, the system controller 7 detects whether or not the recording signal is being recorded on the optical disk 1 in step ST1. When the system controller recognizes that the recording is being performed (Yes in ST1), the first integration circuit 1
7. The system controller 7 detects the voltage of the lens displacement signal integrated by the second integration circuit 18 and compared with a predetermined value by the comparison circuit 19.

If the amount of lens displacement exceeds a predetermined amount in step ST2 (Yes in ST2), the process proceeds to step ST2.
In 3 stop recording. For example, if the track pitch is 1.6
It is determined whether or not the lens displacement exceeds 0.3 μm. When the displacement amount of the lens is equal to or less than the predetermined amount, (S
(No in T2), the processing from step ST1 is repeated. According to the present invention, the amount of displacement of the lens can be detected as a physical quantity, so that the amount of displacement of the lens can be detected more reliably than in the past.

[0018]

According to the present invention, the displacement of the lens is detected by detecting the driving current applied to the lens actuator and calculating the acceleration proportional to the driving current. The calculation can be performed accurately, and the off-track can be reliably detected and the recording can be stopped. Therefore, when the track goes to the previously recorded information part, the destruction of the recorded information due to overwriting is prevented, and when the track goes to the unrecorded part,
When the optical disc to be recorded is of a non-rewritable type (write-once type), it is possible to prevent information from being unable to be newly recorded.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the apparatus of the present invention.

FIG. 2 is a circuit diagram showing an embodiment of an integration circuit for detecting a lens displacement amount according to the present invention.

FIG. 3 is a waveform chart at each point in the circuit diagram of FIG. 2;

FIG. 4 is a circuit diagram showing an embodiment of an actuator driven by a constant current drive circuit.

FIG. 5 is a block diagram showing an embodiment of detecting a lens displacement amount when using an actuator driven by a constant current drive circuit.

FIG. 6 is a flowchart showing processing of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 optical disk 23 amplifier 2 drive circuit 24 drive coil L 3 spindle motor 4 optical pickup 5 head amplifier 6 phase compensation circuit 7 system controller 8 decoder 9 output terminal 10 feed motor 11 input terminal 12 encoder 13 laser control circuit 14 operation unit 14a playback button 14b Record raw button 14c Stop button 15 Display 16 Actuator current signal detection circuit 17 First integration circuit 18 Second integration circuit 19 Comparison circuit 20 Resistance (R1) 21 Resistance (R2) 22 Resistance (R3)

Claims (1)

[Claims] 1. An optical disk recording / reproducing apparatus for irradiating a laser beam to an optical disk from a lens supported by a lens actuator and recording while tracing tracks of the optical disk, wherein a drive current of the lens actuator is integrated to detect a lens speed. (1) integrating means, second integrating means for detecting the displacement of the lens from the speed, means for comparing the detected displacement of the lens with a predetermined lens displacement, and when the displacement of the lens exceeds a predetermined position. An optical disc recording / reproducing apparatus characterized by further comprising control means for stopping recording.