JPH0877688A - Optical disc player - Google Patents

Abstract

PURPOSE: To protect an optical disc and a player against damage due to abnormal operation at the time of high speed rotation by detecting an FG pulse and stopping a driver immediately upon detection of abnormal application of load to a spindle motor. CONSTITUTION: When an optical disc 3 is unclamped 4, for example, and the load being applied to a spindle motor 1 varies abruptly to lessen the rotary load, the period T2 decreases significantly as compared with the period T1 of normal rotation. It is detected by an FG detector and a CPU 7 makes a decision that an abnormal operation has occurred and interrupts power supply to a drive circuit immediately. A motor control circuit 8 delivers a control output for interrupting power supply to the motor 1. Consequently, the motor 1 deviates from accelerating state and then decelerates through friction of the shaft or the like to stop quickly. In case of a CLV disc, data of the width of pulse generated during normal operation relative to the position of an optical pickup 9 is stored in a memory and compared with a rotational period corresponding to the position of the pickup 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for protecting a player and a disc when an abnormal operation occurs in a rotary drive system of an optical disc reproducing device such as a laser disc player.

[0002]

2. Description of the Related Art As a method of detecting an abnormal operation such as the disc being out of the clamped state due to an abnormal operation such as tilting the player or vibration during reproduction, continuous defocusing and reproduction of information is performed. Detecting missing parts etc.,
After the error was detected, the servo system was re-controlled to correct the abnormal operation.

[0003]

However, in the conventional method for detecting an abnormal operation of the disk reproducing apparatus, it is difficult to detect the abnormal operation, and there is a drawback that the processing corresponding to the abnormal operation takes too much time. Therefore, the load applied to the motor is lightened due to the disc coming out of the clamped state or floating during high-speed rotation, and the turntable rotates abnormally at high speed.For a moment, the turntable is trying to properly connect to the turntable during high-speed rotation. It was not possible to prevent the player and the disc from being damaged due to the disc coming off from the turntable being spattered and rotating at high speed and coming off and rotating at high speed.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a device for rotating and reproducing an optical disk, a drive means for mounting the optical disk on a turntable and rotating, a pulse generating means for detecting the rotation and generating a pulse, and a pulse. The optical disk reproducing apparatus includes means for measuring a pulse generation signal output from the generating means and detecting a load abnormality applied to the driving means, and detecting the load abnormality and stopping the driving means. Further, in an apparatus for rotating and reproducing an optical disc, a motor for mounting the optical disc on a turntable and rotating it,
Pulse generation means for detecting rotation of the motor and generating pulses, FV conversion means for converting the number of pulses generated by the pulse generation means into a voltage to obtain a rotation speed information signal, and acceleration information signal from the rotation speed information signal. The optical disk reproducing apparatus includes means and a detecting means for detecting that the acceleration information signal deviates from the normal range, and stops the motor.

[0005]

[Function] FG (Frequency Generato)
r) Detecting the pulse width or cycle, and immediately judging the sudden change as abnormal occurrence, and decelerating and stopping the rotation of the disk, the high-speed rotation of the disk or the player and the FG servo are disengaged. The abnormal operation state is stopped, and damage to the player and the disc can be prevented. Also, the number of pulses of the signal generated from the pulse generating means,
By performing FV conversion from the pulse period or pulse width to obtain the acceleration signal from the rotation speed signal, it is possible to determine that an abnormal operation has occurred when exceeding a predetermined fluctuation width, and it is possible to improve the detection accuracy of the rotation abnormality.

[0006]

EXAMPLES The present invention will be described by way of examples. FIG. 1 is a block diagram showing one embodiment of the present invention. CD on the turntable 2 which is rotated by the spindle motor 1.
Alternatively, an optical disk 3 such as an LD is placed and fixed by a clamper 4. A detection circuit 6 detects a pulse generated from an FG pulse generator 5 provided in a spindle motor 1 for rotating an optical disk 3 in proportion to the number of revolutions, and a signal processing is performed by a microcomputer (CPU) 7 to generate a motor. The rotation control of the spindle motor 1 is performed via the control circuit 8. The CPU controls the focus servo F, the tracking servo TR, the sled servo SL, etc. to reproduce the signal recorded on the optical disk 3 which is rotationally driven, and the reproduction circuit 10 reproduces the signal reproduced from the optical pickup 9. Audio and video signals are processed by AOU after signal processing.
It is output from T11 and VOUT12.

FIG. 2 is a diagram for explaining the operation of determining an abnormality in the output pulse of the FG pulse generator. In FIG. 2, when the disk is normally rotating at a constant angular velocity (CAV), for example, the rotation speed is about 1800 rpm, and the period of the FG pulse including the time axis fluctuation component (jitter, rotation unevenness, etc.) is T1 = 3.3. It is ± 1.0 [ms], and the range of normal rotation should be within 30%. When the load applied to the spindle motor 1 suddenly changes due to an abnormal operation such as the optical disk 3 being disengaged from the clamp 4 and the rotational load is reduced, the cycle T2 becomes a cycle T2 << T1 and this is abnormally operated by the FG detection device. It is determined by the CPU 7 that the power supply to the drive circuit is stopped immediately after time t1.
By outputting a control output from the motor control circuit 8 to supply power to the spindle motor 1 and stopping the supply of drive power, the spindle motor 1 deviates from the accelerating state, decelerates due to shaft friction, etc., and stops immediately after time t2. To do. In the case of a CLV disk with a constant linear velocity, the rotation cycle of the pulse width generated during normal operation changes depending on the position of the optical pickup 9 with respect to the optical disk 3. Therefore, the relative comparison data is stored in a storage device and the optical pickup 9 is used. The abnormal rotation is detected by comparison detection with the rotation cycle corresponding to the position.

Although the CPU 7 detects and determines the above, FIG. 3 shows a comparison circuit according to another embodiment of the present invention. When an abnormality is detected by this detection circuit, the power supply circuit of the spindle motor is cut off so that the abnormal rotation increase can be stopped. The number of pulses generated from the FG device 5 is converted into a voltage (A) as speed information by the FV converter 13, and converted into acceleration information (B) by the differentiating circuit 14. FIG. 4 shows the motion determination range. The output of the differentiating circuit 14 is input to the window comparator 15 whose upper and lower limits are set to the threshold value of the normal operation range, and immediately (after T ') its output (C) is output as an abnormal operation detection signal, which is not shown. Also shuts off the power switch of the spindle motor 1 and stops the motor. In this way, it is possible to immediately detect and stop an abnormality in the mounting relationship between the turntable 2 and the clamper 4 that connect the optical disk 3 that rotates at high speed and the spindle motor 1 that drives and controls the optical disk 3 at high output.

[0009]

According to the present invention, an FG pulse is detected, an abnormality in the load applied to the spindle motor is immediately detected, and the drive unit is stopped. Therefore, damage to the optical disk or the apparatus due to an abnormal operation that occurs when the optical disk rotates at high speed can be prevented. Can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment according to the present invention.

FIG. 2 is a diagram illustrating an abnormal operation.

FIG. 3 is a block diagram of another embodiment of the present invention.

FIG. 4 is a diagram illustrating a determination range.

[Explanation of symbols]

 1 Spindle Motor 2 Turntable 3 Optical Disc 4 Clamper 5 FG Pulse Generator 6 Detection Circuit 7 CPU 8 Motor Control Circuit 9 Optical Pickup 10 Reproduction Circuit 11 AOUT 12 VOUT 13 FV Converter 14 Differentiation Circuit 15 Wind Comparator 16 Servo Circuit

Claims (2)

[Claims] 1. An apparatus for rotating and recording and reproducing an optical disk, wherein the optical disk is mounted on a turntable and rotated, a drive means for detecting the rotation, a pulse generating means for generating a pulse, and an output from the pulse generating means. An optical disk reproducing apparatus comprising means for detecting an abnormal change in the load applied to the driving means from the pulse signal generated, and stopping the driving means upon detecting the abnormal change. 2. A device for rotating and recording and reproducing an optical disk, wherein a motor rotates the optical disk by mounting the optical disk on a turntable, pulse generating means for detecting rotation of the motor and generating a pulse, and the pulse generating means. FV conversion means for converting the generated pulse into voltage to obtain a rotation speed information signal, means for obtaining an acceleration information signal from the rotation speed information signal, and detection means for detecting that the acceleration information signal deviates from the normal range. An optical disk reproducing apparatus comprising: