JPS6233359A - Positioning device for disk-shaped recording media - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a positioning device for a disk-shaped recording medium (hereinafter referred to as a disk), and is characterized by an adjusting means for aligning the center of the disk with the center of rotation. It is something.

2. Description of the Related Art Hereinafter, an example of a conventional positioning device for a disc-shaped recording medium will be described with reference to the drawings. FIGS. 4 and 6 show a conventional positioning device. In FIG. 4, a disk 1 without a center hole is suctioned onto a turntable 2 by vacuum suction means. 3 is a bearing, and an aerostatic bearing is used here. 4 is a motor for driving the turntable 2; 5 is a vacuum tube connected to the vacuum suction means; 0; the positioning means 6 includes a roller 7 connected to the disk 1; a bearing 8 supporting it; and a belt attached to the roller 7. a guide 11 that supports a motor 10 that applies rotational force through a motor 9 and a bearing 8 so as to be movable in the radial direction of the disk 1;
The device is composed of a linear drive unit 12 that transmits linear drive to the linear drive unit 1, and a motor 13 that provides driving force to the linear drive unit 12. Also, a laser device 14 is provided as a means for detecting the amount of eccentricity of the disk 1. 016 converts the beam 16 into an electrical signal. It is a detector.

FIG. 6 is a circuit block diagram of a positioning device for a disc-shaped recording medium, and FIG. 6 is a waveform diagram of each part thereof.

The amount of eccentricity of the disk 1 is detected by a detector 16, the detected output a is amplified by an AC amplifier 17, the output is full-wave rectified by an absolute value circuit 18, and the output C is reduced by a smoothing circuit 19 to reduce ripple. The waveform shown in FIG. 5d is obtained.

On the other hand, the reference voltage generation circuit 20 generates a voltage corresponding to the allowable eccentricity of the disk 1, and the voltage and the smoothing circuit 1
When the output voltage e from the smoothing circuit 19 is higher than the reference voltage, the motor control circuit 22 causes the motor 13 to move the roller 7 at a constant speed toward the center of the disk 1. Continue to send current so that it gradually moves. When the voltage e becomes equal to the reference voltage, the motor control circuit 22 sends a current to the motor 13 so that the roller 27 moves away from the disk 1, and at the same time, the motor 10, which is rotating the roller 7, is make it stop.

Problems to be Solved by the Invention However, in such a conventional configuration, when the output voltage e of the smoothing circuit 19 is larger than the output voltage of the reference voltage generation circuit 20, the motor control circuit 22 generates a signal that the voltage e becomes equal to the reference voltage. Since the roller 7 continues to push the disk 1 at a constant speed by sending a constant current to the motor 13 until Become,
In view of the above-mentioned conventional problems, the present invention has been developed to enable highly accurate eccentric alignment to be performed. An object of the present invention is to provide a positioning device for a disc-shaped recording medium.

Means for Solving the Problems In order to solve the above problems, the disc-shaped recording medium positioning device of the present invention includes a turntable on which a disc-shaped recording medium is movably mounted, and a turntable that is fixed at a constant position. A rotary drive device that rotates the disc-shaped recording medium at a high speed and an eccentricity detection means that generates an output corresponding to the eccentricity of the disc-shaped recording medium with respect to the rotation center of the turntable are used. The recording medium positioning means and the turntable are moved relative to each other according to the output of the eccentricity detection means, and the relative movement is controlled according to the eccentricity of the turntable.

Effect: With the above-described configuration, the present invention increases the moving speed of the roller when the amount of eccentricity of the disk-shaped recording medium is relatively large (than the allowable amount of eccentricity), and increases the moving speed of the roller when the amount of eccentricity approaches the allowable amount of eccentricity. By lowering the rate of change in the amount of eccentricity of the inner disk-shaped recording medium, it becomes easier to adjust the eccentricity for minute changes, making it possible to adjust the eccentricity with high accuracy of several microns. Become.

Embodiment Hereinafter, a positioning device for a disk-shaped recording medium according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a circuit block diagram of a positioning device for a disk-shaped recording medium in one embodiment of the present invention.

The amount of eccentricity of the disk 1 is detected by a detector 14, the detected output a is amplified by an AC amplifier 17, the output is subjected to full-wave rectification by an absolute value circuit 18, and the ripple is reduced by a smoothing circuit 19 for the output C. The waveform shown in FIG. 2d is obtained. Furthermore, by passing it through a filter 3o, a ripple-free DC voltage as shown in FIG. 2e is obtained.

On the other hand, the reference voltage generation circuit 20 generates an electric seedling corresponding to the allowable eccentricity of the disk 1, and the comparator 21 compares the generated voltage with the output voltage of the filter 30, so that the output voltage from the filter 30 becomes the reference voltage. When larger, the third
As shown in the figure, when the amount of eccentricity is large, the current control circuit 31
The motor control circuit 22 controls the amount of current by
The amount of current flowing to the motor 13 is increased, and the roller 7
Increases movement speed. As the amount of eccentricity of the disk 1 decreases, the output voltage from the filter 30 also decreases, so the current amount is controlled by the current control circuit 31 to reduce the value of the current flowing from the motor control circuit 22 to the motor 13. Slows movement speed.

When the output voltage of the filter 30 becomes equal to the reference voltage, the correction has been completed, and the motor control circuit 22 sends a current to the motor 13 so as to move the roller 7 away from the disk 1, and at the same time rotates the roller 7. The driving motor 10 is stopped.

This completes the correction of the amount of eccentricity.

In this way, according to this embodiment, when the amount of eccentricity is large, the moving speed of the roller is increased, and when the amount of eccentricity is small, the moving speed is decreased, so that
Moreover, in the final stage, the eccentricity can be adjusted with high precision.

Effects of the Invention As described above, according to the present invention, by providing a means for controlling the relative moving speed between the positioning means and the turntable according to the amount of eccentricity of the disk-shaped recording medium, the amount of eccentricity is large. can be moved quickly to perform adjustment efficiently, and moreover, by moving at a low speed in the final stage, eccentric alignment can be performed with high accuracy.

[Brief explanation of the drawing]

Fig. 1 is a circuit block diagram of a positioning device for a disc-shaped recording medium according to an embodiment of the present invention, Fig. 2 is a waveform diagram of the output signal of its eccentricity detector, and Fig. 3 is its eccentricity, voltage, and movement. A speed characteristic diagram, FIG. 4 is a perspective view of the positioning device, and FIG. 6 is a circuit block diagram of a conventional rotary drive device.
FIG. 6 is a signal waveform diagram of each part of the circuit. DESCRIPTION OF SYMBOLS 1...Disc, 2...Turntable, e...Positioning means, 7...Roller, 9...Belt, 1o... ...Motor, 12...Linear drive unit, 13...
・Motor, 14... Laser device, 16...
...Detector, 17...AC amplifier, 1
8... Absolute value circuit, 19... Smoothing circuit, 20... Reference voltage generation circuit, 21...
・Contractor 122...Motor control circuit, 30...Filter, 31...
...Current control circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 2 Zero Plate Invitation Ward d

Claims (1)

[Claims] A turntable on which a disc-shaped recording medium is movably mounted, a rotation drive device that rotates the turntable at a constant speed, and an output that corresponds to the eccentricity of the disc-shaped recording medium with respect to the rotation center of the turntable. a means for detecting the amount of eccentricity that occurs; a recording medium positioning means that is movable toward and away from the outer periphery of the disc-shaped recording medium on the turntable and relatively movable in the diametrical direction of the turntable; and a means for detecting the amount of eccentricity that occurs. A disk-shaped disk-shaped recording medium comprising: a drive means for relatively moving the recording medium positioning means and the turntable according to an output; and a means for controlling the relative moving speed according to the eccentricity of the disk-shaped recording medium. Recording medium positioning device.