JPH01236478A - disc playback device - 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 The present invention relates to a disk playback device that plays back information signals recorded on a disk-shaped recording medium, and particularly to a disk playback device that plays back an information signal recorded on a disk-shaped recording medium, and in particular, a playback device that can play back an information signal recorded on a disk-shaped recording medium, and in particular, a playback device that can play back an information signal recorded on a disk-shaped recording medium. The present invention relates to a disc playback device having functions.

In general, various types of so-called disk playback devices are known that play back information signals from a disk-shaped recording medium on which video signals and the like are recorded. In addition to the normal playback function, a normal disc playback device has two special functions:
Has a pause function.

This function is for temporarily interrupting the playback operation when an emergency such as an incoming telephone call occurs during playback, and restarting the interrupted playback operation from the interrupted part after the requirement is completed.

However, the tracks on a disc-shaped recording medium are normally eccentric, and even if the stylus is lifted once by a pause operation and lowered by the next pause release operation, the stylus will not necessarily be the same as before raising the stylus. It doesn't necessarily mean going down to the truck.

For this reason, conventional video disc playback devices that have a pause function by simply stopping the arm and lowering the stylus by the top four bars with a lifter have a problem with the screen being interrupted during the pause operation due to the eccentricity of the track. There may be cases where it is not played.

Alternatively, there are drawbacks such as the possibility that the data may be reproduced in duplicate.

SUMMARY OF THE INVENTION An object of the present invention is to provide a disc playback device that eliminates the drawbacks of the prior art described above and can always resume playback from the same track as when the pause operation was started when the pause operation is canceled.

In order to achieve this object, the present invention provides a demodulation circuit that demodulates the position information signal attached to each track on a disk-shaped recording medium, and during a pause operation, the position information signal from this demodulation circuit is Temporarily stored in a storage device within the processor.

When the pause operation is canceled, based on the position information signal stored in the storage device, when a locked group (a phenomenon in which the playback head repeatedly plays back the same signal track) occurs, the locked group is canceled. A playback head control device, which is normally provided in the machine, controls the movement of the playback head so that the playback operation always restarts from the same track as when the pause operation was started.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a disc reproducing apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention;
FIG. 2 is a schematic configuration diagram of the pickup section 2 attached to the arm 5 shown in FIG. 1, and FIG. 3 is a configuration diagram of the stylus (playback head) control section.

FIG. 4 shows a coil movement circuit. In FIGS. 1, 2, 3, and 4, 1 is a video disk as a disc-shaped recording medium, 2 is a pickup section, and 3 is a turntable. , 4 is a disc motor.

5 is an arm, 6 is a signal detection circuit, 7 is a signal processing circuit, 8
is a track number demodulation circuit, 9 is a microprocessor, 1
0 is arm motor drive circuit, 11 is arm motor, 12
13 is a reduction mechanism, 13 is a lifter opening circuit, 14 is a lifter, 15 is a coil driving circuit, 16 is a stylus drive coil, 17 is a converter, and 18 is a stylus position detection signal demodulation circuit.

19 is a stylus drive magnet, 20 is a position detection electrode, 21 is a fly lead, 22 is a stylus (reproducing head), 23 is a cantilever, 24° 25.26 and 27
is a transistor, and 28 is a resistor.

In FIG. 1, a disc-shaped recording medium 1 is placed on a turntable 3, and is rotated together with the turntable 3 by a disc motor 4 at a constant rotational speed. A video signal recorded on a track on a disc-shaped recording medium 1 is detected by a pickup section 2 attached to an arm 5.

Hereinafter, for convenience of explanation, the configuration and operation of the pickup section 2 will be first explained using FIGS. 2, 3, and 4.

Stylus 22 attached to the tip of cantilever 23
The tip of the arm 5 protrudes from a hole provided in the bottom surface of the arm 5 and traces a track on the disk-shaped recording medium 1.

Further, the fly lead 21 provided on the stylus 22 transmits the video signal in the track detected by the stylus 22 to the signal detection circuit 6 shown in FIG. In combination, a capacitive stylus position detection device is constructed.

An AC signal voltage is applied between the fly lead 21 and the stylus position detection electrode by a known method, and displacement information of the relative position of the stylus 22 and the arm 5 is transmitted as a stylus position detection signal to the first first The signal is transmitted to the signal detection circuit 6 shown in the figure.

The cantilever 23 has a stylus drive magnet 1.
The magnet 19 and the stylus drive coils 16 arranged on both sides of the magnet 19 constitute a stylus control device. This stylus control device applies a driving pulse to a stylus drive coil 16 when a locked group occurs in which the stylus 22 repeatedly traces the same track due to scratches or the like on a track on a disc-shaped recording medium 1. This is normally provided in a video disc playback device to move the track to another adjacent track, and is also utilized to achieve the object of the present invention.

The stylus drive coil 16 is driven by a coil drive circuit 15 shown in FIG. The circuit 15 is composed of four transistors 24 to 27 as shown in the figure, and there are cases in which transistors 24 and 27 are turned on and transistors 25 and 26 are turned on by a control pulse. be. For this reason, the stylus drive coil 16 connected in series with the resistor 23 provided between the connection point of both emitters of the transistors 24.25 and the connection point of both emitters of the transistors 26.27, It is driven by pulse currents in different directions depending on the control state of 27. In the stylus control device shown in FIG. 3, a stylus drive magnet 19 attached to a cantilever 23 is magnetized with an N pole at the top and an S pole at the bottom, and two magnets placed on both sides of the magnet 19. The stylus drive coils 16 are connected in series. Now, when a pulsed current is applied to the stylus drive coil 16 and the coil is excited to the electrode indicated by the solid line in FIG. When viewed from above, the stylus 22 and the upper portions of the stylus drive magnet 19 are driven in the direction indicated by the solid arrow. In addition, the stylus drive coil 1
When 6 is excited with the polarity indicated by the dotted line character, the upper portions of the stylus 22 and the stylus drive magnet 19 are driven in the direction indicated by the one dotted arrow. As a result, the stylus 22 is moved to an adjacent track in the inner or outer circumferential direction.

Referring again to FIG. 2, the cantilever 23 of arm 5
A fritter 14 is provided at a position along. During the PAUSE operation, this lifter 14 is controlled to drive the cantilever 23 upward to move the stylus 22 upward away from the track.

Next, the operation of the video disc player according to the present invention will be explained with reference to FIG.

The video signal and stylus position detection signal recorded on the track on the disc-shaped recording medium 1 detected by the pickup section 2 described above are applied to the signal processing circuit 7 via the signal detection circuit 6, and are subjected to well-known signal processing. It is performed. The output of the signal processing circuit 7 is as follows.

The signal is sent to the television receiver via the converter 17, and also to the track number demodulation circuit 8 and the stylus position detection signal demodulation circuit 18. The track number demodulation circuit 8 extracts the track number information (position information signal) inserted into each vertical retrace period in the video signal, converts it into a parallel data format, and sends it to the microprocessor 9.

The microprocessor 9 has a storage device therein,
Every time new track number information is input from the track number information demodulation circuit 8, the track number information in the storage device is updated, and the track number information is monitored to detect whether a locked group has occurred. Upon detecting that a locked group has occurred, the microprocessor 9 controls the stylus drive coil 1 via the stylus drive circuit 15.
6, the stylus 22 is moved to an adjacent track inside the disc-shaped recording medium 1, and the locked group is released. The movement of the stylus 22 in this case takes place as already explained with reference to FIGS. 3 and 4.

During the playback operation of the Pidio disc player, a pause command is issued to the microprocessor 9 using a pause key (not shown) or the like.
When the microprocessor 9 receives the input, the microprocessor 9 causes the current track number information stored in the above-described internal storage device to be held, and stops the operation of the arm drive circuit 10 to stop the operation of the arm 5. let The microprocessor 9 then provides a control signal to the lifter 14 via the lifter drive circuit 13. As explained with reference to FIG. 2, the one or more states in which the lifter 14 controls the cantilever 23 to move the stylus 22 upward away from the track are the pause states of the video disc reproducing apparatus.

In order to cancel the above-mentioned pause state and restart the playback operation of the video disc playback device, a pause release command is issued to the microprocessor 9 by the pause key or other keys.
When the input signal is input, the microprocessor 9 gives a control signal to the lifter 14 via the lid drive circuit 13 to lower the stylus 22 onto the track on the disc-shaped recording medium 1.

When the stylus 22 comes into contact with the track and a playback operation is started, the microprocessor 9 receives the track number information from the track number information demodulation circuit 8 and the track number information stored in the storage device within the microprocessor 9 immediately before the pause operation. The stylus drive coil 16 is controlled via the stylus drive circuit 15 to move the stylus 22 in the inner circumferential direction or the outer circumferential direction so that both track number information match. That is, the microprocessor 9 determines which track number information is larger as a result of the comparison described above, and accordingly, the microprocessor 9 determines which track number information is larger.
The stylus drive circuit 15 is controlled by determining whether the stylus drive coil 2 has descended to the inner trunk or the outer track of a predetermined track, determines the excitation direction of the stylus drive coil 16, and controls the stylus drive circuit 15. In this way, the stylus 22 is moved to the same track as before the pause operation, but during this time the video signal is muted, and when the stylus 22 completes moving to the same track before the pause operation, the muting If this is canceled and playback is performed while commuting to school, the continuous video signal from before the pause operation can be played back even after the pause operation is canceled.

The stylus position detection signal demodulation circuit 18 extracts the stylus position displacement signal from the stylus position detection device described in FIG. The microprocessor 9 controls the arm motor 11 via the arm motor drive circuit 10 based on the stylus position signal from the stylus position detection signal demodulation circuit 18 . The rotation of arm motor 11 controls movement of arm 5 via deceleration mechanism 12 . The arm 5 is controlled to move in the inner circumferential direction of the disk-shaped recording medium 1 in accordance with the movement of the stylus 22 in the inner circumferential direction of the disk-shaped recording medium 1 while tracing a track.

As described above, according to the present invention, it is possible to provide a disc playback device that can always perform a playback operation correctly from the signal at the start of the pause operation after the pause operation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
FIG. 2 is a configuration diagram of the pickup section 2 in FIG. 1,
FIG. 3 is a configuration diagram of a stylus control section, and FIG. 4 is a circuit diagram showing an example of a coil drive circuit. 1... Disc-shaped recording medium, 2... Pink-up portion, 3
... Turntable, 4... Disc motor, 5.
... Arm, 6... Signal detection circuit, 7... Signal processing circuit, 8... Track number demodulation circuit, 9... Microprocessor, 10... Arm motor drive circuit, 11
...Arm motor, 12...Deceleration mechanism, 13...
Lifter drive circuit, 14... Lifter, 15... Coil drive circuit, 16... Stylus drive coil, 17...
Converter, 18... Stylus position detection signal demodulation circuit, 19... Stylus drive magnet, 20...
...Position detection electrode, 21...Fly lead, 22.
...Stylus (playback head), 23...Cantilever, 24,25°26.27...Transistor, 28
···resistance.

Claims (1)

[Claims] 1. A playback head that traces a track formed on the disk-shaped recording medium and detects a positional information signal together with the information signal recorded on the disk-shaped recording medium, and demodulates the positional information signal reproduced by the playback head. In a disk playback device equipped with a position information signal demodulation circuit and a playback head control device that supplies a pulse current to a drive coil included in the playback head to move the playback head to an adjacent signal track, when the playback operation is paused, the current A storage device that stores a position information signal, and when the pause is released, the position information signal stored in the storage device is compared with the position information signal output from the position information signal demodulation circuit when playback is resumed, and the playback is performed. The above control signal determines the direction of the pulse current flowing through the drive coil of the head and sequentially moves the reproducing head to adjacent tracks in the inner circumferential direction or outer circumferential direction depending on the comparison result until both position information signals match. 1. A disc playback device comprising: a microprocessor that supplies a playback head control device.