JP2705264B2 - Information recording disk playback device - Google Patents

Description

The present invention relates to an information recording disk having information recorded on both sides thereof, without reversing the information recording disk.
The present invention relates to an information recording disk reproducing apparatus capable of reproducing an opposite surface.

2. Description of the Related Art In recent years, information recording disk playback devices have become widespread in various fields,
Higher performance is also being promoted in consumer devices such as video disk playback devices.

Hereinafter, an example of the above-described conventional information recording disk reproducing apparatus will be described with reference to the drawings.

FIG. 3 shows a block diagram of a conventional video disk reproducing apparatus. In FIG. 3, 31 is a video disk, 32 is a rotation speed detecting device for detecting the rotation speed of the video disk 31, and 33 is the video disk 31 by moving itself without turning over the recording surface of the video disk 31. 31
A pick-up device for reading out signals from both sides of the pick-up device, a sync signal detecting device for detecting a sync signal from a signal read from the video disk 31 by the pick-up device 33, a rotation speed detected by the rotation speed detecting device 32, or a sync signal A rotation speed control device that generates a rectangular wave signal for controlling the rotation speed of the video disk 31 from the synchronization signal detected by the detection device 34 and generates a signal obtained by smoothing the signal by a smoothing circuit, 36 is a rotation speed control device. A rotation drive device for rotating the video disk 31 in accordance with a signal generated by the device 35, and a rotation direction indicator device 37 for instructing the rotation drive device 36 on a rotation direction.

A description will be given of an example of an operation of reversing the rotation direction in order to reproduce the opposite surface from the recording surface being reproduced in the video disk reproducing device configured as described above.

Rotation speed control device during playback of video disc 31
35 uses the synchronization signal detected by the synchronization signal detection device 34,
A rectangular wave signal that maintains a rotation speed suitable for reproduction is generated, and the signal is smoothed by a smoothing circuit, and then output to the rotation driving device 36.

Also, when the rotation direction of the video disc 31 is reversed,
While monitoring the rotation speed detected by the rotation speed detection device 32, the rotation speed control device 35 generates a rectangular wave signal that decelerates until the video disk 31 stops rotating, and accelerates after the rotation stop, As in the case of the above-described reproduction, the signal is smoothed by a smoothing circuit, and then output to the rotation driving device 36.

At the time of this reversal, the rotation direction instructing device 37 gives a rotation direction instruction of the reverse rotation to the rotation driving device 36 when the rotation speed detecting device 32 confirms the stop of the rotation.

 FIG. 4 shows the waveform of each signal at the time of inversion.

The time constant of the smoothing circuit included in the rotation speed control device 35 is as follows:
The value is appropriate when the video disc 31 is reproduced. The rectangular wave signal generated by the rotation speed control device 35 always passes through the smoothing circuit. Therefore, as shown in FIG.
Even if the rotation speed control device 35 generates a rotation speed control signal of a rectangular wave from deceleration to acceleration when the rotation direction is reversed, the smoothed rotation speed control signal output to the rotation drive device 36 has a time delay of 4-A. Occur. There was a problem that the video disk 31 could not be quickly inverted because of the period of 4-A.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides an information recording disk reproducing apparatus capable of quickly reversing the rotation direction when reproducing an opposite surface of an information recording disk.

Means for Solving the Problems In order to solve the above problems, the information recording disk reproducing device of the present invention detects the rotation direction to reverse the rotation direction to reproduce the opposite surface of the information recording disk, and detects the rotation speed by the rotation speed detecting device. When the rotation speed is equal to or lower than a certain speed, a time constant switching device is provided to make the time constant of the smoothing circuit in the rotation speed control device smaller than otherwise.

According to the present invention, when the rotation direction of the information recording disc is reversed, the time constant switching device improves the signal given to the rotation drive device by the time constant switching device, and the reversal can be quickly performed.

Embodiment A video disk reproducing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a video disk reproducing apparatus according to an embodiment of the present invention. In FIG. 1, 11
Is a video disk, 12 is a rotation speed detector that detects the rotation speed of the video disk 11, and 13 is a pickup that reads signals from both sides of the video disk 11 by moving itself without turning over the recording surface of the video disk 11. Device, 14 is a synchronization signal detection device for detecting a synchronization signal from a signal read from the video disk 11 by the pickup device 13, 15 is the rotation speed detected by the rotation speed detection device 12, or the synchronization detected by the synchronization signal detection device 14. From the signal, a rectangular wave signal for controlling the rotation speed of the video disk 11 is generated, and a rotation speed control device for generating a signal obtained by smoothing the signal by a smoothing circuit, and 16 according to the signal generated by the rotation speed control device 15 A rotation drive device for rotating the video disc 11, a rotation direction indication device 17 for instructing the rotation drive device 16 in the direction of rotation, and an information recording data device 18. When reversing the rotation direction to reproduce the opposite surface of the disc 11, if the rotation speed detected by the rotation speed detection device 12 is lower than a certain speed, the smoothing in the rotation speed control device 15 is performed more than otherwise. This is a time constant switching device for reducing the time constant of the circuit.

A description will be given of an example of an operation of reversing the rotation direction in order to reproduce the opposite surface from the recording surface being reproduced in the video disk reproducing device configured as described above.

During playback of the video disc 11, a rotation speed control device
15 uses the synchronization signal detected by the synchronization signal detection device 14,
A rectangular wave signal that maintains a rotation speed appropriate for reproduction is generated, and the signal is smoothed by a smoothing circuit, and then output to the rotation driving device 16.

Also, when the rotation direction of the video disc 11 is reversed,
While monitoring the rotation speed detected by the rotation speed detection device 12, the rotation speed control device 15 generates a rectangular wave signal that decelerates until the video disc 11 stops rotating, and accelerates after the rotation stop, As in the case of reproduction, the signal is smoothed by a smoothing circuit and then output to the rotation drive device 16.

At the time of this reversal, the rotation direction indicating device 17 gives a rotation direction instruction of the reverse rotation to the rotation driving device 16 when the rotation speed detecting device 12 confirms that the rotation has stopped. Further, when the rotation speed detected by the rotation speed detection device 15 is equal to or lower than a certain speed, the time constant switching device 18 controls the rotation speed control device 15 more than otherwise.
To reduce the time constant of the smoothing circuit inside.

 FIG. 2 shows the waveform of each signal at the time of inversion.

As described above, according to the present embodiment, by providing the time constant switching device, the time delay 2-A of the rotational speed control signal after smoothing can be reduced as compared with the conventional 4-A, and Reversal is possible.

Effect of the Invention As described above, the present invention provides a method for reversing the rotation direction for reproducing the opposite surface of an information recording disc, when the rotation speed detected by the rotation speed detection device is equal to or lower than a certain speed, By providing a time constant switching device that makes the time constant of the smoothing circuit in the rotation speed control device smaller than in the case of, the signal given by the rotation speed control device to the rotation drive device is improved,
Quick reversal becomes possible.

[Brief description of the drawings]

FIG. 1 is a block diagram of a video disk reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a waveform diagram of each signal when an information disk is inverted in an embodiment of the present invention, and FIG. FIG. 4 is a block diagram, and FIG. 4 is a waveform diagram of each signal when the information disk is inverted in the conventional example. 11 Video disc, 12 Rotational speed detector, 13
... Pickup device, 14 ... Sync signal detection device, 15 ...
Rotation speed control device, 16 ... Rotation drive device, 17 ... Rotation direction indicating device, 18 ... Time constant switching device, 31 ... Video disc, 32 ... Rotation speed detection device, 33 ... Pickup device, 34 ... ... Synchronous signal detection device, 35 ... Rotation speed control device, 36 ... Rotation drive device, 37 ... Rotation direction indicating device.

Claims (1)

(57) [Claims] An information recording disk on which information including a synchronization signal is recorded on both sides; a rotation speed detecting device for detecting a rotation speed of the information recording disk; A pickup device for reading signals from both sides of the information recording disk, a synchronization signal detection device for detecting a synchronization signal from a signal read from the information recording disk by the pickup device, a rotation speed detected by the rotation speed detection device, Alternatively, a rotation speed control device that generates a rectangular wave signal for controlling the rotation speed of the information recording disk from the synchronization signal detected by the synchronization signal detection device and generates a signal obtained by smoothing the signal by a smoothing circuit. A rotation drive device for rotating the information recording disk in accordance with a signal generated by a rotation speed control device; When reversing the rotation direction to reproduce the opposite surface of the disk, if the rotation speed detected by the rotation speed detection device is equal to or lower than a certain speed, the smoothing circuit in the rotation speed control device is more than otherwise. An information recording disk reproducing device, comprising: a time constant switching device for reducing the time constant of the information recording disk;