JPH01315093A - Searching method for disk player - Google Patents

Abstract

PURPOSE:To prevent the occurrence of searching errors by shifting a pickup at high speed up to a position near a desired point in case the total reproduction time is longer than a prescribed level to perform a pulse feed searching action and then performing the searching action just with the feed of pulses in case the total reproduction time is shorter than the prescribed level. CONSTITUTION:In case the reproduction time of a compact disk 1 exceeds 20min, the time needed for shift to a desired position (d) from the present track position (c) is calculated. Then a searching action is performed up to a track position (e) preceding the position (d) by an optical pickup 3 via the high-speed thread feed. Then the mode is switched to a pulse feed searching mode and the searching actions are carried out by the 1-pulse/100-track jump of a 1st step, the 1-pulse/10-track jump of a 2nd step, and the 1-pulse/1-track jump of a 3rd step respectively. While only the searching action using the pulse feed is carried out in case the reproduction time of the disk 1 does not exceed 20min. In such a way, the searching errors can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a search method in a disc player that takes search error prevention into consideration.

"Prior Art" FIG. 3 is a block diagram showing the configuration of a disc player.

In the figure, 1 is a compact disc (hereinafter referred to as CD)
, 2 is a spindle motor that rotationally drives the CDI, 3 is an optical pickup that reads digital bit information on the recording surface of the CDI, and 4 is a feed motor that moves this optical pickup 3.

The above CDI contains digital audio information and TOC.
Information etc. are recorded. Among these, the TOC+R information is recorded on the innermost track of the CDI, and the total performance time (that is, the total playback time of digital audio information) is 13 minutes, and the TOC+R information is recorded on the innermost track of the CDI, and the total playing time (that is, the total playback time of digital audio information) is 13 minutes. The performance of the first song starts and the entire performance ends after Te minutes, the performance (playback) time of the first song is T1 minutes, the performance time of the second song is 13 minutes, etc. This is table of contents information consisting of. The above optical surprise 3 includes a semiconductor laser, an objective lens, an optical sensor, a focus actuator (focus adjustment mechanism), and a tracking actuator (tracking adjustment mechanism).
It is composed of etc. 5 is an RF amplifier that amplifies the read signal output from the optical pickup 3; 6 is a signal processing circuit that demodulates the amplified read signal and corrects code errors; and 7 converts the digital read signal into an analog audio signal. 8 is an audio circuit that performs amplification processing of audio signals, and 9 is an output terminal. Further, a servo controller 10 and a servo circuit 11 are provided to control the spindle motor 2, optical pickup 3, and feed motor 4. The servo controller 10 is composed of a CPU (central processing unit), a ROM in which a control program is recorded, a RAM for data recording, and an I10 board, and creates various control signals and sends them to the servo circuit 11, etc. do. Also,
Above servo circuit 1! performs startup control and CLV servo control (constant linear velocity control) of the spindle motor 2, focus servo control, and tracking servo control of the optical pickup 3 based on various control signals supplied from the servo controller 10.

When using a disc player with the above configuration, conventionally, a so-called high-speed search method is used to move the optical pickup 3 at high speed from the current track position to the track position where the beginning of the target track is recorded (target track position). is being explored.

This method is as follows.

Using the above TOC information, we know the time required to perform from the current track position to the target track position, and perform arithmetic processing using this required time and linear velocity (relative track running speed of the optical pickup). Calculate the number of tracks to the target track position. Next, the sled is moved at high speed while measuring the number of jump tracks until the measured value of the number of tracks reaches the calculated value. By this method, the optical pickup 3 is moved at high speed to near the target track position.

``Problem to be solved by the invention'' By the way, the linear velocity differs depending on the various CDs (12 m /
s~1.4 m/s), the number of tracks from the current track position to the target track position calculated by the above method includes an error.

Therefore, according to the conventional search method described above, feeding errors occur due to high-speed thread feeding, and the optical pickup
There were cases where the machine ran over and over towards the outer circumference of D.

In this case, the movement range of the optical pickup is set according to the diameter of a normal CD (12 cm), so it will not be a big problem when using a normal CD, but if you use a CD single (8 cm in diameter) or CDV
When using (CD with video), the following problems have been a problem. That is, in the case of a CD single with a small outer diameter, the optical pickup may come out of the CD, causing the disc to run out of control.

Furthermore, in the case of CDVs, the maximum length of the digital audio recording portion is 20 minutes, so the optical pickup could get stuck in the video track and cause the disc to go out of control.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a search method for a disc player that takes measures to prevent runaway of a high-speed pickup during a high-speed search.

"Means for Solving the Problem" The present invention provides a search method for a disc player that moves an optical pickup from a current track position to a target track position, in which all digital information is searched based on table of contents information recorded at a predetermined position on a CD. It is determined whether the playback time is longer than a predetermined time, and if it is determined that the playback time is longer than a predetermined time, the optical pickup is first moved close to the target track position by high-speed feeding, and then, Search is performed by pulse sending, while
If it is determined that the total playback time is less than or equal to a predetermined time, the above problem is solved by performing a search only by sending pulses.

"Operation" According to the present invention, the total playback time of digital information is determined, and if the total playback time is greater than or equal to a predetermined time, a search including high-speed forwarding is performed; In this case, only the search by pulse sending is performed.

Thereby, it is possible to avoid an accident in which the optical pickup runs out of control during a search caused by different types of CDs.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 and 2 are explanatory diagrams for explaining the operation of a search method for a disc player according to an embodiment of the present invention. The search operation in the disc player according to this embodiment is performed by the following procedure.

In this embodiment, from the read TOC information, the playback time of the digital audio portion, that is,
It is determined whether the required tracing time from the innermost track a to the outermost track b exceeds 20 minutes. The subsequent search method differs depending on the results.

(a) When the required playback time exceeds 20 minutes An example of this case will be explained with reference to FIG. This is the case when using regular CDs, where the digital audio portion can be up to 74 minutes.

In this case, the number of tracks from the current track position C to the destination track position d is calculated from the required time and the like using the same method as in the conventional example. Using this result, the feed motor 4 performs a search by high-speed thread feeding of the optical pickup 3 to a predetermined track position e before the target track position d, and after reaching the predetermined track position e, a search is performed by pulse feeding. You can switch to search. In the above-mentioned search by pulse sending, the first stage is a 1-pulse 100 track jump, the second stage is a 1-pulse 10 track jump, and the third stage is a 1-pulse 1 track jump.
A search is performed by track jump. That is,
As a first step, the optical pickup 3 is caused to jump 100 tracks every time one pulse of the drive command signal is applied to the feed motor 4. As a result, the optical pickup 3 further approaches the target track position d, and after reaching the track position f, a second stage search by IO track jump is performed every time one pulse is applied. As a result, after reaching a track position g that is close to the target track position d, a search is performed in which the optical pickup 3 moves one track for each pulse in the third stage. In this way, the optical pickup 3 can be moved to the target track position d at high speed.

(b) When the required playback time does not exceed 20 minutes: This case applies when using a CD single or CDV whose digital audio portion is at most 20 minutes.

In this case, the search by high-speed thread feeding described in (a) above is not performed.

Then, as shown in FIG. 2, only a search is performed by pulse feeding. That is, after the number of tracks from the current track position C to the target track position d is calculated by the same method as above, the track jump is performed by one pulse of 100 in the first stage to a predetermined track position before the target track position d. A search is performed, and then a second stage search is performed with one pulse and 10 track jumps to a track position i that is closest to the target track position d, and finally,
3rd stage 1 pulse to target track position d! A search is performed using track jump.

The above example is generally applied to a disc player for normal music playback, but is not limited to this.
It can also be applied to playback devices such as ROM, CD-[(compact disc interactive media), CD-■ (compact disc video), and LD (laser disc).

"Effects of the Invention" As explained above, according to the search method for a disc player of the present invention, if the total playback time of digital information is longer than a predetermined time, a search including high-speed forwarding is performed; If the total reload interval is less than a predetermined time, only a search is performed by pulse feed, so even if the target track position is overrun, the optical pickup will not run out of control, regardless of the type of CD. can be avoided. In other words, for CDs whose total playback time is longer than a predetermined time, even if an overrun occurs due to high-speed forwarding, runaway can be avoided because the same type of digital information is still recorded, and the total playback time can be reduced. For CDs whose duration is less than a predetermined time, the search is performed only by pulse feeding, so overrun does not occur, and runaway can therefore be avoided. In the latter case, since the maximum travel distance of the optical pickup is relatively short, the relatively slow search speed is not a substantial problem.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams for explaining the operation of a search method in a disc player according to an actual example of the present invention, and FIG. FIG. 2 is a block diagram showing the electrical configuration of such a disc player. l...Compact disc (CD), 3...
...Optical pickup, 4...Feed motor, U...Innermost track position, b...
Outermost track position, C...Current track position, d...Target track position, es', g
* hs r...Other intermediate track positions.

Claims (1)

[Claims] In a search method for a disc player in which an optical pickup is moved from a current track position to a target track position, based on table of contents information recorded at a predetermined position on the disc, the total playback time of digital information is equal to or longer than a predetermined time. If it is determined that the time is longer than a predetermined time, the optical pickup is first moved close to the target track position by high-speed feeding, and then a search is performed by pulse feeding. On the other hand, if the total playback time is determined to be less than a predetermined time, the search is performed only by pulse feeding.