JPS60187978A - Disc reproducing device - Google Patents

Abstract

PURPOSE:To position the head of a desired music at a high speed by moving a pickup at a high speed on the basis of the detection signal from a pickup position detecting mechanism. CONSTITUTION:A slide device 5 is provided with a mechanism which detects the moving position of a pickup 4, and the pickup 4 is moved at a high speed within the precision of this mechanism. In this case, this position detecting mechanism 10 fractionizes the moving position of the pickup, and a slit plate 12 provided with slit groups 11 of the binary mode is fixed in parallel with the moving direction of the pickup, and a light source 13 and a sensor block 15 provided with a photodetector group 14 are connected and fixed to the pickup 4 on both sides of the plate 12 and are moved together with the pickup 4 as one body, and the position of the pickup 4 is detected digitally in accordance with a light reception pattern of the photodetector group 14. As the result, ony the device 5 is moved without applying servo to reach the position where the pickup 4 just goes out from a lead-in track, and servo is applied from this position to read information on a disc 1, and thus, reproducing is started from a more accurate position.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a playback device for a 1d1 video disc or an audio disc, and more particularly to an improvement in a method for locating the beginning of information recorded on a disc.

<Prior art> Conventionally, for example, on an audio compact disc, in addition to music information, the song number and elapsed time of the music are recorded, and each piece of music is recorded in the lead intratrack before the music information begins. The address (absolute time, etc.) at which the song number starts is recorded. That is, after the lead-in rank, from 0 minutes 00 seconds onward from the first song, addresses are recorded that increase, for example, every second along with music information.

Therefore, by reading and storing the track number and address using the lead intratrack, it is possible to locate the beginning of a desired track number.

In other words, the information read in the lead intratrack for the first song:
O minutes OO seconds, 2nd song: 3 minutes 34 seconds, 3rd song: 12 minutes 40
second, 4th song: 20 minutes 10 seconds, etc., and 4th song -1
It becomes possible to randomly play a desired song from the beginning of the song, such as the third song.

However, the song or address is unknown until the information on the disc can be read, and in order to reach the desired song, the pickup must be moved little by little to read the information on the disc and search for the desired song. This search was time consuming and inconvenient.

<Purpose> The present invention has been made for the purpose of enabling the above-mentioned search to be performed at high speed.

<Example> Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an outline of a disc playback device. In the figure, 1 is a disc, 2 is a turntable on which the disc 1 is mounted, 3 is a spin motor that rotates the turntable 2 in a fixed direction at high speed, and 4 is a spin motor that rotates the disc 1 at high speed. A pickup 5 that optically reads signals from the bottom surface is a slide device that moves the pickup 4 in the radial direction.
The pickup 4 is slid in the forward and reverse directions by being driven in the forward and reverse directions by the motor 7.

Then, the optical signal from the disk 1 is picked up by the pickup 4.
A servo control circuit 8 processes this electrical signal to control the spin motor 3 and pickup slide motor 7, and digital information on the disk 1, such as music, music track number, address, etc. A disk reproducing apparatus is constituted by electrical means such as the decoder circuit 9 for converting the data into a 100% 100 kHz data, and the above-mentioned mechanical means.

The servo control circuit 8 converts the reflected light from the disk 1 of the laser beam emitted from the pickup 4 into an electrical signal using the light receiving element, and then focuses the laser beam on the disk surface so that the signal becomes clearer. A focus servo is applied to ensure that the lines match, and a tracking servo is applied to ensure that the linear track does not deviate from the linear track. The tracking servo works to trace according to the track, but beyond a certain range (1 to 2 mm) it exceeds the movable range and the servo comes off, so a slide device 5 is used to move the pickup 4 at the same time as the tracking servo. .

In the above configuration, in the present invention, the slide device 5 is equipped with a mechanism for detecting the moving position of the pickup 4, and the pickup 4 is moved at high speed to within the accuracy of this detection mechanism.

FIG. 2 shows an example of the position detection mechanism 10, in which the pickup movement position is subdivided into the vicinity of the pink-up 4.
A slit plate 12 in which this is indicated by a group of slits 11 in binary mode is fixed parallel to the pick-up moving direction, and a sensor block 15 equipped with a light source 13 and a light-receiving element group 14 is placed on both sides of the slit plate 12, and a sensor block 15 is attached to the pick-up 4. The light receiving element group 14 is configured to be movable together with the pickup 4 by being connected and fixed to each of them, and the position of the pickup 4 is digitally detected based on the light receiving pattern of the light receiving element group 14.

By using this pickup position detection mechanism 10, in order to search up to the 4th track in the above example, pick up 4 must be located at the position where the lead intra track is exited, that is, at 0 minute O.
Assuming that the position is at O seconds, the high speed is reached by moving only the slide device 5 without applying the servo at a position change of 20 minutes and 10 seconds, and then the servo is applied to move the disk 1.
, and more accurate location, i.e. 20 minutes 10
It is possible to start playing from the second (fourth song) onwards.

Note that various types of pickup position detection mechanism 10 are conceivable. For example, as shown in FIG. Alternatively, the rotation speed of the pulley 16 may be detected from the number of output pulses from the Hall element 18, and the pickup position may be calculated based on this. Further, as a means for detecting the rotation speed of the pulley 16, a disk having a transparent slit or a small hole formed on the circumference may be attached to the pulley 16, and a photo sensor may be used to detect the light pulse transmitted through the slit or the small hole. ,
Possible means include adding a disk with a gear portion formed on the periphery to the pulley 16, and providing a pickup coil opposite the gear portion to measure the output pulse. or,
It is also possible to detect the pickup position in an analog manner using a linear potentiometer.

<Effects> As explained above, according to the present invention, in order to locate the beginning of desired information, the pickup position can be adjusted without having to intermittently apply a servo to move the pickup little by little to read the information. Based on the detection signal from the detection mechanism,
The pickup can be moved all at once to near the beginning of the desired information without applying the servo, making it possible to cue at an extremely high speed compared to conventional methods.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a disc playback device, FIG. 2 is a partially cutaway perspective view showing an example of a pickup position detection mechanism,
FIG. 3 is a perspective view showing another embodiment of the pickup position detection mechanism. 1. Disk, 4. Pickup, 5. Slide device, 10. Pickup position detection mechanism.

Claims (1)

[Claims] (1) In a disc playback device that irradiates a disc 1 with information such as video and audio recorded with a light beam and reads information based on optical changes, a slide moves the pickup 4 that reads information from the disc 1 in the radial direction of the disc. The device 5 is equipped with a detection mechanism 10 for detecting the moving position of the pickup 4, and configured to move the pickup 4 at high speed using the detection result from the detection mechanism 10 to the vicinity of the desired information location on the disk 1. A disc playback device characterized by: