JPH08249797A - Optical disk reproducing device - Google Patents

Abstract

PURPOSE: To prevent slippage by instantly changing the rotation of a spindle motor by providing a means for rotating an optical disk, a slip detecting means of the optical disk and a means for controlling the revolving speed of the rotating means. CONSTITUTION: A count value of a 1st counter 7 for showing the revolving speed of the spindle motor 5 and a count value of a 2nd counter 8 for showing the revolving speed of the optical disk 1 are compared with each other. When the count value of the counter 7 is larger than the count value of the counter 8, it is judged that a slip is taking place between the dusk 1 and a turntable, and the motor 5 is decelerated. On the other hand, when the count value of the counter 7 is smaller than the count value of the counter 8, it is judged that the motor has suddenly been decelerated, and the revolving speed is controlled to be increased. The control of the control means 10 is performed to make the count value of the counter 7 and the count value of the counter 8 always equalized. Thus, the slippage 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 disk reproducing device.

[0002]

2. Description of the Related Art For example, a magneto-optical disk reproducing apparatus records and reproduces information by irradiating a focused micro laser beam spot on the magneto-optical disk while rotating the magneto-optical disk. Further, in a disc-shaped information record carrier such as a magneto-optical disc, information recording tracks are provided concentrically or spirally, and the light emitted from an optical head is rotated by rotating the optical disc at a constant rotational speed or linear velocity. Information is recorded or reproduced by causing the beam to follow the recording track.

[0003]

When the turntable is rotated to access the optical disc mounted on the turntable of the optical disc reproducing apparatus, the spindle motor, which is the rotating means of the turntable, attempts to shorten the start-up time. If a large amount of current is applied, the optical disc will slip with the turntable. Even when the current flowing through the spindle motor is suddenly stopped in an attempt to stop the recording / reproducing of the optical disk, the optical disk slips with the turntable.

Therefore, in the case where the rapid increase / decrease of the current flowing through the spindle motor is eliminated and the increase / decrease is made gentle, it takes a long time to access the optical disk. It is an object of the present invention to provide an optical disc reproducing apparatus that can eliminate slip between the optical disc and the turntable of the optical disc reproducing apparatus and shorten the access time to the optical disc.

[0005]

In order to solve the above problems, according to the present invention, a rotating means for rotating an optical disk, a first rotating speed reading means for reading the rotating speed of the rotating means, and a rotating speed of the optical disk are set. An optical disk reproducing device is constituted by a second rotation speed reading means for reading, a calculation means for obtaining a difference between the rotation speed of the rotation means and the rotation speed of the optical disk, and a control means for controlling the rotation speed of the rotation means.

[0006]

In the present invention, the means for reading the number of rotations of the rotating means of the optical disc and the means for reading the number of rotations of the optical disc are provided. It is possible to know whether or not a slip has occurred with the turntable. If there is a difference between the number of revolutions of the optical disc rotating means and the number of revolutions of the optical disc, it can be determined that slip has occurred. In this case, the control means can decelerate or accelerate the rotating means of the optical disc to eliminate the slip.

[0007]

1 is a block diagram showing the configuration of an optical disk reproducing apparatus according to this embodiment. The optical disc 1 inserted in the optical disc reproducing device and a laser beam from a semiconductor laser (not shown) are condensed and irradiated onto a target position of the optical disc for recording, and the reflected light is converted into an electric signal. An optical pickup 3 for reproducing information, a coarse movement motor 4 for moving the optical pickup 3 in the radial direction of the optical disc 1, a spindle motor 5 for rotating the optical disc 1, and a rotation speed of the spindle motor 5. The first counter 7 for recording, the second counter 8 for recording the number of revolutions of the optical disc 1, the calculating means 9 for obtaining the difference between the number of revolutions of the spindle motor 5 and the number of revolutions of the optical disc 1, and the rotating means of the optical disc. It is composed of control means 10 for decelerating or accelerating the rotating means of the optical disk when there is a difference between the rotating speed and the rotating speed of the optical disk.

When the optical disc 1 is inserted from the insertion opening of the optical disc reproducing device, it is pulled in by the loading mechanism of the optical disc reproducing device. When the optical disk 1 is pulled up onto the turntable of the optical disk reproducing device, the spindle motor 5 starts rotating. with this,
The optical disc 1 mounted on the turntable also starts to rotate. The optical pickup 3 emits the laser light 2 and focuses it on the recording / reproducing surface of the optical disc 1. The condensed laser beam 2 is reflected by the recording / reproducing surface of the optical disc 1 and returns to the optical pickup 3 again. The laser beam 2 returning to the optical pickup 3 traces the same optical path as when it was emitted, but the optical path is bent at a right angle by a beam splitter (not shown). Then, the laser light 2 is converted into an electric signal by a light receiving element (not shown), and is sent to a control circuit (not shown) of the coarse movement motor 4 and a second counter 8 for counting the number of rotations of the optical disk 1. Sent. The rotation speed of the spindle motor 5 is sent to the first counter 7 in real time. The counter value of the first counter 7 and the second
The counter value of the counter 8 is sent to the calculating means 9. The calculation means 9 constantly calculates the difference between the two counter values. The result of this calculation is sent to the control means 10 which controls the rotation speed of the spindle motor 5. The control means 10 controls the rotation speed of the spindle motor 5 based on the difference between the count value of the first counter 7 and the count value of the second counter 8 sent from the calculating means 9. The counter value of the first counter 7 that indicates the rotation speed of the spindle motor 5 is the second counter 8 that indicates the rotation speed of the optical disc 1.
If it is larger than the counter value of
Since it is considered that a slip has occurred between the spindle motor 5 and the turntable that rotates in synchronization with the spindle motor 5, the spindle motor 5 is decelerated to control the rotation speed. On the other hand, when the counter value of the first counter 7 indicating the rotation speed of the spindle motor 5 is smaller than the counter value of the second counter 8 indicating the rotation speed of the optical disc 1, the spindle motor 5 is decelerated rapidly. Since it is considered that the slip occurred due to the above-mentioned operation, the control is performed so as to increase the rotation speed. The control means 10 controls so that the counter value of the first counter 7 and the counter value of the second counter 8 are always equal.

[0009]

As described above, according to the present invention, the rotation speed of the spindle motor and the rotation speed of the optical disk can be known in real time. As a result, when there is a difference in the number of rotations, that is, when a slip occurs between the optical disk and the turntable that rotates in synchronization with the spindle motor, the number of rotations of the spindle motor is instantaneously changed to Can be prevented. Further, since the spindle motor is rotated at a high speed while the slip is not detected, the access time to the optical disk can be shortened.

[Brief description of drawings]

FIG. 1 is a block diagram showing an optical disc reproducing apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 1 ... Optical disc 2 ... Laser light 3 ... Optical pickup 4 ... Coarse movement motor 5 ... Spindle motor 6 ... Slip control circuit 7 ... First counter 8 ... 2 counter 9 ... arithmetic means 10 ... control means

Claims (2)

[Claims] 1. An optical disk reproducing apparatus comprising: rotating means for rotating an optical disk; slip detecting means for the optical disk; and control means for controlling the number of rotations of the rotating means. 2. Rotating means for rotating the optical disk, first rotation speed reading means for reading the rotation speed of the rotation means, second rotation speed reading means for reading the rotation speed of the optical disk, and rotation of the rotation means. 2. The optical disc reproducing apparatus according to claim 1, further comprising: a calculating unit that obtains a difference between the number of rotations of the optical disc and a control unit that controls the number of rotations of the rotating unit.