JPH048866B2 - - Google Patents

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 disk playback device that plays 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 systems are known for so-called disk playback devices 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 disk playback device has a pause function as one of its special functions. This function is designed to temporarily interrupt the playback operation when an emergency such as an incoming telephone call occurs during playback, and then resume the interrupted playback operation from the interrupted point after the requirement is completed.

However, the tracks on a disc-shaped recording medium are normally eccentric, and even if the stylus is raised once by a pause operation and lowered by the next pause release operation, the stylus will not always be the same as before the stylus was raised. It doesn't necessarily mean going down to the truck. For this reason, conventional video disk playback devices that have a pause function by simply stopping the arm and raising and lowering the stylus with a lifter do not play the screen midway through the pause operation due to the eccentricity of the track. However, there are disadvantages in that there are cases in which the playback is repeated, or in cases where the playback is repeated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a disc playback device that eliminates the above-mentioned drawbacks of the prior art and can always restart the playback operation 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 disc-shaped recording medium, and during a pause operation, the position information signal from this demodulation circuit is Temporarily stored in the storage device in the processor,
When the pause operation is canceled, the locked group is canceled when a locked group (a phenomenon in which the playback head repeatedly plays back the same signal track) occurs based on the position information signal stored in the storage device. A playback head control device, which is normally provided for this purpose, 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.

Embodiments of the disc playback device 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 pick-up section 2 attached to the arm 5 shown in FIG. 1, and FIG.
The figure shows the configuration of the stylus (playback head) control section, FIG. 4 shows the coil drive circuit, and FIG.
In FIGS. 2, 3, and 4, 1 is a video disk as a disk-shaped recording medium, 2 is a pickup section, 3 is a turntable, 4 is a disk 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, 10 is an arm motor drive circuit,
11 is an arm motor, 12 is a speed reduction mechanism, 13 is a lifter drive circuit, 14 is a lifter, 15 is a coil drive circuit, 16 is a stylus drive coil, 17 is a converter, 18 is a stylus position detection signal demodulation circuit, and 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 are transistors, 28
is resistance.

In FIG. 1, a disc-shaped recording medium 1 is placed on a turntable 3, and is rotated together with the turntable 3 at a constant rotational speed by a disc motor 4. 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 structure and operation of the pickup section 2 will be first explained using FIGS. 2, 3, and 4.

The stylus 22 attached to the tip of the cantilever 23 protrudes from a hole provided in the bottom of the arm 5 and traces a track on the disc-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 via the fly lead 21. The signal is transmitted to the signal detection circuit 6 shown in FIG.

The cantilever 23 is provided with a stylus drive magnet 19, and the magnet 19 and 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 in which the stylus 22 repeatedly traces the same track occurs due to scratches or the like on a track on the disc-shaped recording medium 1. is normally provided in a video disc playback device for moving a track to another adjacent track,
It is also used to achieve the objectives of the present invention.

The stylus drive coil 16 is driven by a coil drive circuit 15 shown in FIG. The circuit 15
is configured as shown in the figure with four transistors 24 to 27, and there are cases in which the transistors 24 and 27 are controlled to be turned on, and cases in which the transistors 25 and 26 are controlled to be turned on by the control pulse. Therefore, the stylus drive coil 16 connected in series with the resistor 23, which is provided between the connection point between the emitters of the transistors 24 and 25 and the connection point between the emitters of the transistors 26 and 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, the stylus drive magnet 19 attached to the cantilever 23 is magnetized with an N pole at the top and an S pole at the bottom, and two magnets arranged 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. The stylus 22 and the upper portions of the stylus drive magnet 19 are driven in the direction indicated by the solid arrow. Furthermore, when the stylus drive coil 16 is excited to the polarity indicated by the dotted line characters, the stylus 22 and the stylus drive magnet 19
The upper part of is driven in the direction indicated by the 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, a fritter 14 is provided at a position along the cantilever 23 of the arm 5. During the PAUSE operation, the flitter 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 aforementioned pickup section 2 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 sent to a television receiver via a converter 17, as well as to a track number demodulation circuit 8 and a 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 interval 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, and each time new track number information is input from the track number information demodulation circuit 8, the microprocessor 9 updates the track number information in the storage device and updates the track number information. Monitor 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 has already been shown in FIGS. 3 and 4.
This is done as explained in the figures.

When a pause command is input to the microprocessor 9 using a pause key (not shown) or the like while the video disc player is in playback mode, the microprocessor 9 reads the current data stored in the above-mentioned storage device inside the microprocessor 9. The track number information is held, and the operation of the arm drive circuit 10 is stopped to stop the operation of the arm 5. Thereafter, the microprocessor 9 provides a control signal to the lifter 14 via the lifter drive circuit 13. Lifter 14 controls cantilever 23 to move stylus 22 upwardly away from the track, as explained in conjunction with FIG. The above state is the pause state of the video disc playback device.

When a pause cancellation command is input to the microprocessor 9 using the pause key or other keys in order to cancel the pause state and restart the playback operation of the video disc playback device, the microprocessor 9 activates the lifter. A control signal is applied to the lifter 14 via the drive circuit 13, and the stylus 22 is slowly lowered 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 pause operation stored in the storage device within the microprocessor 9. 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 the track number information immediately before is compared with the previous track number information and the track number information matches. That is, the microprocessor 9 determines which track number information is larger as a result of the comparison described above, and thereby determines whether the stylus 22 has descended to the inner track or the outer track of the predetermined tracks. The stylus drive circuit 15 is controlled by determining the excitation direction of the stylus drive coil 16. 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 kept in a muting state, and when the stylus 22 has completed moving to the same track before the pause operation, the muting is canceled. If normal playback is performed, 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
The stylus position displacement signal from the stylus position detection device explained in the figure is separated and extracted from the video signal, converted into parallel digital signals, and sent to the microprocessor 9. 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 the playback operation correctly from the signal at the start of the pause operation after the pause operation.

[Brief explanation of drawings]

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 the stylus control section, and FIG. 4 is a coil diagram. FIG. 2 is a circuit diagram showing an example of a drive circuit. DESCRIPTION OF SYMBOLS 1...Disk-shaped recording medium, 2...Pickup section, 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 (reproducing head), 23... Cantilever, 24, 2
5, 26, 27...transistor, 28...resistor.

Claims (1)

[Claims] 1. A playback head that traces a track formed on a disc-shaped recording medium and detects a position information signal along with an information signal recorded on the disc-shaped recording medium, and demodulates the position information signal reproduced by the playback head. A disc playback device comprising a position information signal demodulation circuit for detecting a position information signal, and a playback head control device for supplying a pulse current to a drive coil of the playback head to move the playback head to an adjacent track,
A storage device that stores the position information signal at that time when the playback operation is paused, and a storage device that stores the position information signal at that time when the playback operation is paused.
The position information signal stored in the storage device is sequentially compared with the position information signal output from the position information signal demodulation circuit upon resuming playback, and each time the drive of the playback head is adjusted according to the comparison result. to the drive coil in order to determine the direction of the pulse current flowing through the coil and to sequentially move the reproducing head to adjacent tracks in the inner circumferential direction or outer circumferential direction according to the comparison result until both position information signals match. 1. A disk reproducing device comprising: a microprocessor for supplying a control signal for applied pulse current to the reproducing head control device.