JPH01119967A - System for preventing projection of pickup - Google Patents

Abstract

PURPOSE:To prevent the spring-out of a pickup from a compact disk by calculating the number of tracks required for the shift of the pickup and the shifting time and stopping the shift of the pickup by the lapse of a calculating time and the clearance of the number of the tracks. CONSTITUTION:The number of the tracks where the pickup 1 shifts from a present position to an objective position is calculated, and the time require for shifting the number of the tracks is calculated, and then the pickup 1 is shifted accompanied by the start of time counting, whereby the shift of the pickup 1 is stopped by the elapse of the time obtained by calculation, and the clearance of the number of the tracks. Since the pickup 1 stops not only by the number of the tracks but by the elapse of the prescribed time, it can accurately be stopped at the objective position even if there is a scar in the compact disk 1. Thus, the spring-out of the pickup from the compact disk can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a pickup, particularly a pickup of a compact disc player, which prevents the pickup from jumping out from the outer edge of a compact disc into which it is inserted. Regarding.

[Prior Art] - In terms of C, as shown in Figure 2, the pickup 1 in a compact disc player roughens the servo to increase the access speed when the playback position on the compact disc 2 is farther from the existing position. In this state, a high-speed search process in which only the pickup 1 is moved at high speed can be performed.

This high-speed search process has conventionally been executed as shown in the flowchart shown in FIG. In other words, the conventional high-speed search processing
The start position of the V song (cumulative time during disc playback) is read from the OC into the RAM as first data, and the number of tracks corresponding to the cumulative time during disc playback is stored in the ROM of the microcomputer built into the player. Put it above and use it as the second data. Then, first, the track number corresponding to the playback position where the pickup is currently located is determined using this second data, and then the drag number corresponding to the target position is also determined from the second data. . Next, the number of trunks that the pickup l should move is calculated from these two truck numbers. Once the number of trunks to be moved is determined, the servo is placed in a rough state and only the movement of pink-up 1 is started, and a decision is made as to whether or not the required number of trunks has been moved.

This decision is repeated until the required number of tracks is cleared, and the criterion is based on the signal received from the LSI every 128 tracks.
If this signal is not received, a deadlock will occur. With this decision, when it is confirmed that the pickup l has moved by the required number of tracks, the pink up 1 stops moving, and the servo changes from the rough state to the normal state and starts the search process, that is, to adjust the focus. , the desired song on the compact disc is played.

(Problems that the invention seeks to solve) However, according to the conventional high-speed search processing method described above, if the compact disc is scratched, the signal that is supposed to come from the LSI cannot be read, and pink-up occurs. 1 continues to move as it is, and a situation arises in which it pops out from the outer edge of the compact disc 2, as shown by the imaginary line in FIG. , the pickup L cannot be stopped, or a focus error occurs and the focus is not adjusted, and after repeating the error process many times, the return process is 1゛8~20 in order to return the pickup L to the inner circumference of the compact disc 2. It will take a long time.

Therefore, the present invention has been made by focusing on the problems of the related art, and solves the problems by accurately stopping the pickup at the target position regardless of scratches on the compact disc. The object of the present invention is to provide a method for preventing a pickup from flying out.

[Means for solving problems]

In order to achieve this objective, the method for preventing the pick amplifier from jumping out according to the present invention calculates the number of tracks that the pink amplifier will move from its current position to the target position, and calculates the time required to move the pick amplifier by that number of tracks. The method is characterized in that the pickup is calculated, and then the pickup is moved when a time count starts, and the movement of the pickup amplifier is stopped when the time obtained by the calculation has elapsed or the number of tracks is cleared.

[Function] Since the moving pick amp is stopped by the process described above, it does not depend only on the number of tracks, but also stops after a predetermined time has elapsed, so even if there is a scratch on the compact disc, it can be corrected. The target position does not suddenly stop and jump out from the outer edge of the compact disc.

[Example] Next, an example of the implementation of the present invention will be described in detail with reference to FIGS. 1A to 1B.

FIGS. 1A to 1B are flowcharts showing the process of the pink-up pop-out prevention method according to the present invention, and the premise is that first data similar to the conventional one is stored in the RAM, and
The second data is stored in the ROM, and the time required to move a predetermined number of tracks is calculated in advance, and the third data is stored in the microcomputer's ROM. Using this data, calculate the number of tracks (number) corresponding to the current playback position and the number of trunks (number) corresponding to the target position to which Pickup 1 is trying to move.
seek. Next, calculate the number of trucks that the pickup 1 will move from the difference between the two numbers of trucks, and then
From the number of tracks, the time required for the pickup 1 to move the number of tracks is determined using third data. Specifically, this calculation reduces the number of tracks to be moved to 128.
This can be done by dividing by the track. Subsequently, a time count is started, the servo is put into a rough state, and only the pickup 1 starts moving. Next, the movement of the pickup l is stopped depending on whether the time obtained by the calculation has elapsed or the required number of tracks has been moved.
The camera returns from its rough state, focuses, and begins playing.

According to this embodiment, the Y-type disk.

Even if the pickup 2 is scratched, if the pickup 1 moves within the calculated time, the pickup 1 will stop moving regardless of whether the number of tracks is cleared. Further, even if the predetermined time has not elapsed, if the number of tracks is cleared, the movement of the pickup 1 is of course stopped.

〔Effect of the invention〕

As described above, according to the pickup prevention method according to the present invention, in addition to the number of trucks required for movement, the time required to move the number of trunks is also calculated. Even if the number of tracks cannot be accurately counted due to scratches on the compact disc, even if no signal is received from the LSI, the pickup will stop moving after the required time has elapsed, so the pickup will not protrude beyond the outer edge of the compact disc. , it is possible to prevent it from coming off.

[Brief explanation of the drawing]

Figures 1A and 1B are flowcharts showing the process of the pickup prevention method according to the present invention, Figure 2 is a diagram showing the positional relationship between the pink-up and the compact disc, and Figure 3 is a flowchart showing the conventional process. It is. 1...Pickup 2...Compact Disc IA Figure 1B Search l: Enter Figure 2 Figure 3 Booko jL! To L1

Claims (1)

[Claims] Calculate the number of tracks that the pickup will move from the current position to the target position, calculate the time required to move the number of tracks, then move the pickup as the time count starts, and perform the calculation according to the above calculation. A method for preventing a pickup from flying out, characterized in that the movement of the pickup is stopped when the obtained time elapses or the number of tracks is cleared.