KR930009642B1 - Pick-up transfer method and mechanism - Google Patents

Abstract

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Description

Pickup Move Method and Mechanism

1 is a plan view of an optical disc.

2 is an explanatory diagram for the pick-up movement operation according to the method of the present invention.

3 is a partial cross-sectional view of the pickup moving apparatus of the present invention.

4 is a schematic diagram of a pickup moving apparatus of the present invention.

* Explanation of symbols for main parts of the drawings

1: disk 2: hub

9: plate 11: disc drive motor

18: pickup 21: objective lens

27: comparator

The present invention relates to a method and mechanism for moving a pickup for an optical disc playback system, for example an optical audio disc or a video disc player.

1 shows an optical disc 1 mounted on an optical audio disc or video disc player. The disc 1 comprises a clamp hub 2 comprising a center hole 3, an annular lead-in 4 around the hub 2, and a pit train pulse-coded modulated outward of the projection 4. It consists of an information storage section 5 for storing the dense video or audio information in the form, and a lead-out 6 at the edge of the disc 1.

As shown in FIG. 2, the information storage unit 5 includes a first information storage unit 7 adjacent to the lead-out 6 and a table-of-content adjacent to the lead-in 4. Or TOC storage (8). The first information storage unit 7 includes a plurality of first information units K to K + n arranged in order from the TOC storage 8 toward the lead-out 6. Each first information unit consists of a first index pit train and a music pit train including multiplexed control pit trains. The control pit train consists of time code data and music identification number data, all of which are required to reproduce the music pit train as music. The TOC store 8 comprises a second index pit train identical to the first index pit train, each pit train being repeatedly recorded in hundreds of information tracks in strips as narrow as 1-2 mm.

An optical system consisting of a semiconductor laser and a photodetector, comprising a turntable, comprising a disk drive motor, which is located on the hub 2 of the disk 1 to drive the music pit train, and which the disk drive motor directly drives as its axis. A conventional optical disc player composed of a pickup including a pickup and a pickup moving mechanism for moving the pickup in the radial direction of the disc 1 is provided.

The semiconductor laser transmits the laser beam to the information track on the disk 1. The photo detector receives the laser beam reflected by the information track and whose array is reflected to convert the pulse code modulated optical signal derived from the reflected laser beam into an electrical pulse signal. First, the pickup movement mechanism positions the pickup in reverse with respect to the index train of the TOC storage unit 8 corresponding to the music pit train to be played, and then the pickup reads the index pit train and moves it according to the index or pointer into memory in the player. After outputting the pit train, the pickup is moved to the music pit train of the information storage unit 5.

This pickup movement mechanism requires a very accurate and expensive position sensor that can accurately detect the position error as zero for the movement of the pickup in the target index track in the TOC storage section 8. In addition, the mechanism must itself be very accurate in the player.

[Purpose of invention]

It is an object of the present invention to provide an improved method and mechanism for moving the pickup of the optical disc reproducing system in opposition to the target index track in the TOC storage 8 without having to detect the zero position error as zero.

[Essence of invention]

In order to carry out the object of the present invention, a pick-up movement method is applicable to an optical disc reproducing system, the system comprising an optical disc, which has a first information store comprising essential information and first control information and which is provided with a first disc. There is a TOC store containing only the second control information identical to the first control information track, wherein the disc includes a pick-up following the information track and a pick-up movement mechanism for moving the pick-up radially relative to the disc. The method installs a limit switch on the outer side opposite to the TOC storage, and when starting playback, moves the pickup toward the limit switch until the pickup activates the limit switch so that the first information storage unit has a predetermined distance to the opposite position. Moving the pickup and then moving the pickup in a direction opposite the target track of the second control information track until the pickup reaches the point opposite the target track of the second control information track.

In addition, the pick-up movement mechanism includes a limit switch, which is located outside of both the first information storage portion and the TOC storage portion and can be activated by the movement of the pick-up, which mechanism is also the first and the second. And a confirmation circuit for checking whether the pickup exactly faces the target track of the control information track. The pickup movement mechanism moves the pickup to a position opposite to the first information store by a predetermined distance after the pickup has activated the limit switch, and the pickup circuit is operated until the confirmation circuit confirms that the pickup is facing the target track of the second control information track. 2 Move the pickup to a position opposite the target track of the control information track.

[Effects of the Invention]

The pickup movement method and mechanism eliminates the need for detection of the zero position error of the pickup and at the same time eliminates the need for very precise and expensive position sensors. In addition, the method and mechanism eliminates the need for the movement of high precision limit switches and the screws for these switches.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the invention are described in more detail with reference to FIGS.

As shown in FIG. 3, the frame plate 9 extends in the radial direction opposite the disk 1 and covers the entire radiation width from the lead-in 4 to the lead-out 6. ). The disc drive motor 11 is mounted at the lower center of the frame plate 9. The shaft 12 of the disc drive motor 11 protrudes on the frame plate 9 through the center hole 13. The flanged upper end 14 of the shaft 12 is adjacent only to the hub 2 of the disk 1. The case 15 of the pickup moving device 16 is attached to the lower part of the frame plate 9. The moving shaft 17 extends radially to the disk 1 and is firmly attached to the case 15.

The pickup 18 includes a body 19 coupled with a moving shaft 17, a dual axis mover 20 mounted on the body 19, an objective lens 21, and a semiconductor laser (not shown). And a pick-up moving motor (not shown). The dual axis actuator 20 is an electromagnetic linear motor for moving the objective lens 21 in a direction perpendicular to the plane of the disk 1 and an electromagnetic linear motor for precisely moving the objective lens 21 in the radial direction of the disk 1. consist of. A pickup moving motor (not shown) cooperates with the moving shaft 17 and moves the body 19 in the radial direction of the disk 1.

The limit or confirmation switch 22 is fixed to the lower part of the frame plate 9 at the inner end 23 of the slot 10. The confirmation switch 22, which is a kind of compact and flat type switch, is simple and inexpensive, and includes a lead-type actuator 24 protruding downward. The mover 24 shown in FIG. 2 is located at the bottom of the lead-in 4, and the objective lens of the TOC storage 8 in the radial direction of the disc 1 is inwardly aligned with the already programmed start-up process. When a virtual beam spot is formed by passing through (since the semiconductor laser is not yet operating) it is kicked by the body 19. The confirmation switch 22 thus confirms that the pickup 18 has reached the TOC storage 8 and sends a signal instructing the immediate movement of the pickup 18 to go to the opposite of the first information storage 7. The pickup 18 is sufficiently returned to ensure that the pickup 18 reaches the first information storage 7 in spite of a possible movement error between the confirmation switch 22 and the pickup 18 and a movement error by the pickup movement motor. come.

4 is a block diagram of a control circuit in the pickup movement mechanism of the present invention. The pickup movement control circuit includes one of the regenerator 25 connected to the output of the photodetector of the pickup 18, the control data separator 26 connected to the output of the regenerator 25, and the control data separator 26. A comparator 27 connected to the output, a memory unit 28 connected to another output of the control data separator 26, a connected confirmation circuit 29 of the memory unit 28, a comparator 27 and a confirmation It consists of an OR circuit 30 which receives the output of the circuit 29, the pickup moving motor drive circuit 31, and the limit switch 22 connected to the output of the OR circuit 30. As shown in FIG.

The player 25 reproduces the first information bit and the index pit train in the TOC storage section 8. The control data separator 26 separates the control data pit string from the first information and the second index. The comparator 27 determines whether the control data separated by the control data separator 26 is a confirmation number indicating an information block K + i of the first information storage unit 7 or an address in the TOC storage unit 8. Determine. Therefore, when the control data is one confirmation number, the comparator 27 sends a pick-up movement signal to the OR circuit 30.

The memory 28 may be large enough to accommodate the ID values for the first and final music selection or other information units or time codes, the time code also being the time taken to play each music block, and the TOC storage unit ( It is the total reproduction time and the time required to reproduce all the music blocks from the first music block to the target music block in the index pit row in 8). The confirmation circuit 29 checks whether the data has been read when there is still any data missing and sends a pickup movement signal to the OR circuit. After the OR circuit 30 receives the pickup movement signal from the comparator 27 or the confirmation circuit 29, the pickup movement motor driving circuit 31 that receives the output of the OR circuit 30 is configured as a first information storage unit ( 7) to the TOC storage section 8, which supplies power to the pick-up moving motor for moving the objective lens 21, in particular the TOC under so-called track jump control over 100 information tracks. It moves from the arbitrary position of the TOC part 8 near the target position of the part 8.

Description of the operation of the embodiment

First, the hub 2 of the disk 1 is fixed to the upper end 14 of the shaft 12, and then a power switch (not shown) is turned on. As shown in FIG. 2B, the pickup moving motor moves the pickup 18 from the stop position toward the confirmation switch 22 so that the body 19 of the pickup 18 is movable, as shown in FIG. 2C. Contacts 24 to cause confirmation switch 22 to be on. Immediately thereafter, as shown in FIG. 2D, the pickup moving motor moves the pickup 18 to the first information storage 7 by a predetermined distance. The fine beam spot generated by the objective lens 21 opposes the first information storage unit 7 and the dual axis mover 20 so that the semiconductor laser and the light detector are turned on. Thus, the pickup 18 starts to obtain the laser beam reflected from the disk 1. As the pickup 18 reads the confirmation number data from the first information block of the first information storage 7, the comparator 27 instructs the pickup 18 to track-jump to the TOC storage 8 to return. Generates a pickup movement signal.

As a track jump is made to the TOC region, if the objective lens 21 of the pickup 18 is offset from the target index track of the TOC storage section 8, the memory 28 fails to store all the check data. Therefore, the confirmation circuit 29 outputs a pickup movement signal which instructs the pickup 18 to track jump to the target index track in the TOC storage section 8. The pickup 18 continues track jumping and reading until the objective lens 21 aligns the target index tracks of the TOC storage section 8 in a row. After the pickup 18 reads the three-check data indicating that the beam spot generated by the objective lens 21 is exactly opposite the target index track of the TOC storage section 8, the pickup 18 changes its operation mode. And move to the first track of the target first information track.

The pickup moving circuit described above can be replaced by a microcomputer having a similar function.

Claims (7)

An optical disc (1) having a first information storage (7) containing essential information and first control information and a TOC storage (8) having only second control information corresponding to the first control information track, An optical pickup 18 that follows the information track, and includes a pickup moving mechanism 16 for radially moving the optical pickup on the disc, the reference position outward relative to both the first information storage and the TOC storage. A pickup moving method for an optical disc reproducing system comprising a limit switch 22 provided in the present invention, comprising: (a) moving the pickup toward a reference position until the pickup starts the limit switch 22 as the playback starts; (B) moving the pickup 18 by a predetermined distance with respect to a position opposite the first information storage section or the TOC storage section, and (c) the pickup is directed to the target track of the second control information track. Moving the pick-up characterized in that consisting of moving the pickup (18) to the opposite side of the target track of the second control information track until it reaches the facing position. 2. The method according to claim 1, wherein in step (c), the pickup repeatedly tracks and samples the information encoded in the opposite track until the target track of the second control track is found. An optical disc (1) having a first information storage (7) containing essential information and first control information and a TOC storage (8) containing only second control information corresponding to the first control information track; And an optical pickup 18 following the information track, including a pickup moving mechanism for radially moving the pickup on the disc, positioned externally to both sides of the first information storage TOC storage. In the pickup movement mechanism including the limit switch 22 activated by the above, the pickup movement mechanism includes a confirmation circuit 29 for checking whether the pickup accurately faces the target tracks of the first and second control information tracks. And the pick-up movement mechanism is located at a position opposite to the first information storage section 7 or TOC storage section 8 by a predetermined distance after the pick-up activates the limit switch 22. Moving up, wherein the mechanism moves the pickup to a position opposite the target track of the second control information track until the confirmation circuit 29 confirms that the pickup is opposite the target track of the second control information track. Pick-up movement mechanism. 4. The pickup movement mechanism according to claim 3, wherein the limit switch (22) is located near the TOC storage (8). 4. The pickup movement mechanism according to claim 3, wherein the limit switch (22) comprises an actuator (24) driven by the contact of the pickup. 6. The pickup movement mechanism according to claim 5, wherein the limit switch is a leaf switch. 7. A pickup movement mechanism according to claim 6, wherein the confirmation circuit includes a temporary memory capable of holding all the second control information and confirms the position of the pickup when the memory is full.

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