JPH1055606A - Detection of centroid deviated disk of disk player - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable saving cost by deciding a disk as the one having the deviated centroid when the servo deviation is caused in a state the gain of the tracking servo making an optical beam follow up to a signal track is lowered than a specific gain. SOLUTION: The disk D is loaded into the disk player, and the rotating speed of the disk D is increased by the rotational driving operation of a spindle motor 2 in accordance with a motor control circuit 12. When the disk D becomes the rotationally driven state at a linear speed of a prescribed multiple of a specified linear speed, the reading operation of TOC data being recorded at the specific position of the disk D is executed. Next, by lowering the servo gain down to the specific value, the operation of which is being performed in a servo signal processing circuit 5 with the control operation of a servo gain control circuit 6, the decision is made whether the servo deviation is generated or not. When the servo deviation is caused, the disk D is decided as the one having the deviated centroid, thereby the economization is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an eccentric disk of a disk player which is configured to read out a signal recorded on a rotating disk by an optical pickup.

[0002]

2. Description of the Related Art Disk players which record information data such as music by digital signals and perform a reproducing operation by reading signals from a disk rotating at a constant linear velocity by using an optical pickup have become widespread. A typical example of such a disc player is a CD player.

In such a disk player, a focusing control operation for focusing a light beam emitted from an optical pickup on a signal surface of the disk and a tracking control operation for following a signal track are performed, and a signal reading operation is performed. And a lock operation of a spindle motor for performing a rotational drive operation of the disk using a synchronization signal in the read signal, that is, a control operation for keeping the disk rotational speed at a constant linear speed. I have.

Recently, a CD-ROM for reproducing a disk called a CD-ROM in which a data signal used for a computer is recorded instead of an audio signal such as music.
Disk players called ROM players have become widespread.

[0005]

The CD-ROM player, unlike the CD player that reproduces an audio signal, requires a high-speed reading operation of a signal. 2. Description of the Related Art Disk players configured to perform a signal reading operation by rotating a disk at a high linear speed such as 6 times, 8 times, and 10 times are commercially available.

[0006] Among disks used in such a disk player, there is a disk called an eccentric disk whose center of gravity is shifted from the center. When such a disk is reproduced in a high-speed rotation state, abnormal vibration occurs. There is a problem of generating abnormal noise.

In order to solve such a problem, it is necessary to detect whether or not the disc is an eccentric disk. However, conventionally, such a detecting operation is expensive because a special element such as an acceleration sensor is used. There was a problem of becoming.

An object of the present invention is to provide a method of detecting an eccentric disk which solves the above problem.

[0009]

According to the present invention, there is provided an eccentric disk when a servo error occurs in a state where the gain of a tracking servo for causing a light beam of an optical pickup to follow a signal track recorded on the disk is lower than a predetermined gain. Is determined.

[0010]

FIG. 1 is a flow chart showing a method of detecting an eccentric disk according to the present invention, and FIG. 2 is a block circuit diagram of a disk player according to the present invention.

In FIG. 2, reference numeral 1 denotes a turntable on which a disk D is mounted and which rotates the disk D;
Reference numeral 2 denotes a spindle motor that drives the turntable 1 to rotate. Reference numeral 3 denotes an optical pickup that irradiates the disk D with a light beam and receives a light beam reflected on the signal surface of the disk D and has an objective lens and the like incorporated therein. (Not shown) so as to be moved in the radial direction of the disk D.

Reference numeral 4 denotes an RF amplifier circuit for amplifying an RF signal obtained from a photodetector of the optical pickup 3 and shaping the waveform, and 5 denotes an optical pickup based on a signal obtained via the RF amplifier circuit 4. 3 performs a focusing control operation for focusing the light beam on the signal surface of the disk D and a tracking control operation for causing the light beam to follow a signal track on the signal surface, and also performs a track operation by a displacement operation of an objective lens constituting the pickup 3. A servo signal processing circuit that performs jump control operations.
Such an operation is configured to be performed by controlling the movement of the objective lens. Reference numeral 6 denotes a servo gain control circuit for controlling the gain of the tracking servo operation by the servo signal processing circuit 5.

Reference numeral 7 denotes a digital signal processing circuit that performs digital signal processing of an output signal output from the RF amplifier circuit 4 and performs demodulation of various signals, and reference numeral 8 denotes a digital signal processed by the digital signal processing circuit 7. A signal reproduction circuit to which a data signal which is a digital signal is input,
It is configured to output a data signal to a computer or the like.

Reference numeral 9 denotes an operation switch 10 for inputting a signal demodulated by the digital signal processing circuit 7 and switching operation of a disc player, or a system control for performing various operation control in accordance with a switching signal output from a computer. It is a circuit and is composed of a microcomputer.

Numeral 11 is a pickup feed control circuit for controlling the feed operation of the optical pick-up 3 by controlling the rotational drive operation of the pick-up feed motor. The operation is controlled by the system control circuit 9. Have been. Reference numeral 12 denotes a motor control circuit for controlling the rotation operation of the spindle motor 2, and the operation is controlled by a motor control signal output from the system control circuit 9.

In such a circuit configuration, when an operation for starting a reproducing operation is performed, first, a focusing control operation for focusing a light beam emitted from the optical pickup 3 on a signal surface of the disk D is performed. The spindle motor 2 is configured to rotate. In addition, when the rotation speed of the disk D is increased by the rotation driving operation of the spindle motor 2 and the rotation speed becomes a lockable rotation speed, a tracking control operation for causing the light beam to follow a signal track recorded on the disk D is performed. And the operation of reading a signal from the disk D is performed. Then, a synchronization signal is detected from the signals read from the disk D, and the operation of locking the rotation speed of the spindle motor 2 using the synchronization signal, that is, the operation of controlling the rotation speed of the disk D to a constant linear speed, is performed. Is configured to do so.

When an operation of reproducing a signal recorded on the disk D at a speed several times higher than a prescribed speed is performed, the motor control circuit 12 rotates the motor 2 at a high speed. In addition, a control operation and a signal processing operation for performing a signal reading operation by the pickup 3 are performed. Then, when the disc D is mounted on the disc player, a read operation of a signal recorded on the disc D is set to a state of performing a highest-speed reproduction operation, and then an eccentric disc determination operation described later is performed. Have been.

As described above, the disc player according to the present invention is configured. Next, the reproducing operation of the present embodiment will be described. When an operation signal for operation of a reproduction switch provided on the operation switch 10 or reproduction from a computer is input, a control operation by the system control circuit 9 is performed, and a reproduction operation state of the disc player is configured. . In the reproducing operation state, the disk D is rotationally driven by the rotation control operation of the spindle motor 2 by the motor control circuit 12 so that the linear velocity becomes constant. Further, in such a state, the optical pickup 3 is driven by the servo operation by the servo signal processing circuit 5.
A focusing control operation and a tracking control operation of the light beam to be irradiated are performed. The tracking control operation is performed based on the servo gain controlled and set by the servo gain control circuit 6.

By performing the above-described control operations, the operation of reading signals from the disk D by the optical pickup 3 is performed normally. The signal read by the optical pickup 3 is input to an RF amplifier circuit 4 where it is amplified and waveform-shaped,
The signal is applied to the digital signal processing circuit 7. After the digital signal applied to the digital signal processing circuit 7 is subjected to digital signal processing, its data signal component is demodulated and input to the signal reproduction circuit 8. The digital signal input to the signal reproducing circuit 8 is output to a computer through an output terminal, and a signal processing operation by the computer is performed.

As described above, the reproducing operation of the disc player according to the present invention is performed. Next, a method of detecting an eccentric disc which is the gist of the present invention will be described with reference to the flowchart shown in FIG.

The operation of detecting an eccentric disk according to the present invention is performed as follows. When the disc D is mounted on the disc player, the disc player is brought into a state of performing a reproducing operation at the maximum speed of the disc player (step A). The rotation speed of the disk D is increased by the rotation driving operation of the spindle motor 2 by the motor control circuit 12, and the focus control operation and the tracking control operation of the optical pickup 3 are performed in parallel with this operation. This operation is performed, and the disk D is rotated at a predetermined multiple of the specified linear velocity by the control operation of the motor control circuit 12 by detecting and utilizing the synchronization signal recorded on the disk D. .

When the disk D is driven to rotate at a linear velocity that is a predetermined multiple of the specified linear velocity, the TOC data recorded at a predetermined position on the disk D is read, and the data is read out. It is determined whether or not the reading has been performed (step B). If the TOC data cannot be read in step B, it is determined that the disk D is an error disk that cannot perform a normal reproducing operation (step C). If it is determined that the disk is an error disk, the reproducing operation of the disk is not performed, and the discharging operation of the disk D and the error displaying operation are performed. In some cases, the disc cannot perform the high-speed reproduction operation but can perform the reproduction operation if the reproduction operation is the low-speed reproduction operation. Therefore, the operation is switched from the low-speed reproduction state to the operation from step B. You can do it.

The reading operation of the TOC data in step B is performed in a high-speed reproducing state. Such a reproducing operation is performed by setting the servo gain set by the servo gain control circuit 6 to a predetermined value. By performing the signal reading operation by such an operation, it is determined that the loaded disk D is not a signal readable disk capable of performing the signal reading operation at high speed, that is, a disk from which a signal cannot be read due to a scratch or the like. (Step D).

After the disc D determination operation is performed, the servo gain of the tracking servo operation performed in the servo signal processing circuit 5 by the control operation of the servo gain control circuit 6 is set to a predetermined value, that is, the eccentricity. In the case of a normal disk other than the disk, the signal reading operation is reduced to a value at which the signal reading operation can be performed normally (step E). When the servo gain decreases to such a value, it becomes difficult to perform the following operation of the light beam with respect to the signal track,
A determination is made as to whether the tracking operation cannot be performed normally, that is, whether or not the servo has deviated (step F).

If no servo slippage has occurred in step F, it is determined that the disk D is not an eccentric disk (step G). If it is determined that the disk D is not an eccentric disk, the control operation of the servo gain control circuit 6 is performed, and the gain of the tracking servo is set back to the gain necessary for performing the high-speed reproduction operation. Therefore, a reproducing operation required by a computer or the like can be performed.

If the servo deviates in step F, it is determined that the disk D is an eccentric disk (step H). If it is determined that the disk D is an eccentric disk, an abnormal vibration occurs and an abnormal sound is generated when the high-speed reproduction operation is performed, so that the disk player is set to a low-speed reproduction state (step I). Thus disk D
If the disc is an eccentric disc, the disc player is set to the low-speed playback state.When the disc player is switched to such a state, the gain of the tracking servo is set to the gain necessary for performing the low-speed playback operation. Become.

In the present embodiment, the servo gain is reduced to a predetermined value when the operation of detecting the center-of-gravity disc is performed. The eccentricity of the core disk can be measured, and the reproduction speed of the disk can be set according to the eccentricity.

[0028]

According to the present invention, it is determined whether or not a servo error occurs in a state where the gain of a tracking servo for making a light beam of an optical pickup follow a signal track recorded on a disk is lower than a predetermined gain. By doing so, whether or not the disc is an eccentric disc is detected, so that it is possible to manufacture the disc at low cost without requiring a special element such as an acceleration sensor.

Further, according to the present invention, when it is determined that the disc is an eccentric disc, the disc player is switched from a state of performing a high-speed reproduction operation to a state of performing a low-speed reproduction operation. Abnormal vibration does not occur during the operation, and generation of abnormal noise can be prevented.

Further, according to the present invention, the servo gain is reduced stepwise during the discrimination operation of the eccentric disk, so that the eccentricity of the eccentric disk can be measured.
The playback speed can be set using the measured eccentricity. Therefore, the playback speed of the disc player can be set to the fastest speed at which abnormal noise due to abnormal vibration does not occur.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a method for detecting an eccentric disk according to the present invention.

FIG. 2 is a block circuit diagram of a disc player according to the present invention.

[Explanation of symbols]

 D disk 2 spindle motor 3 optical pickup 5 servo signal processing circuit 6 servo gain control circuit 7 digital signal processing circuit 9 system control circuit 12 motor control circuit

Claims (4)

[Claims] In a disc player configured to read out a signal recorded on a disc by an optical pickup, a gain of a tracking servo for causing a light beam of the optical pickup to follow a signal track recorded on the disc is adjusted. A method of detecting an eccentric disk of a disk player, wherein the disk is determined to be an eccentric disk when a servo error occurs in a state where the gain is lowered below a predetermined gain. 2. The method for detecting an eccentric disk according to claim 1, wherein when it is determined that the disk is an eccentric disk, the reproduction speed of the disk is switched from a high speed side to a low speed side. 3. The method of detecting an eccentric disk according to claim 1, wherein the operation of determining the eccentric disk is performed while the servo gain is reduced stepwise. 4. The method of detecting an eccentric disk according to claim 3, wherein the disk is rotated at a reproduction speed corresponding to the servo gain at which the detection operation of the eccentric disk was performed.