JPS63188861A - Optical disk retrieval method - Google Patents

Abstract

PURPOSE:To reduce an access time by reading the number of revolutions from a number of revolution control table stored with number of revolutions calculated from a disk actual linear velocity so as to use a control object number of revolutions. CONSTITUTION:A pickup 3 reads the content of a TOC of a Compact disk 2 and uses a detection circuit 13 to detect the disk actual linear velocity V and stores the result in a linear velocity memory 14. A CPU 7 calculates number of revolutions N from the linear velocity V and stores it in the number of revolution control table 15. The number of revolution N of a disk with respect to an object track location is read from the table 15 by a search command and it is used as the number of revolution to be controlled as an object to control the revolution control of a spindle motor 1 via a servo signal processing circuit 6. Thus, after the movement of the optical pickup 3, the number of revolution control waiting time till the disk revolution reaches a normal revolution is minimized to reduce the access time.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical disk search method, and firstly, a search Q.
The present invention relates to a disk rotation speed control method.

[Prior Art] Compact discs (so-called CDs) and readout Tachikawa memories using compact discs (so-called CD-ROMs) use the f3 method of recording constant linear velocity (so-called CLV) as j degrees of disk rotation. is adopted. According to the standard, the linear velocity is 1.2 to 1.4
It is said that a constant speed within the range of +b/s (7 seconds per meter) is sufficient.

As mentioned above, since the disk is written at a constant linear velocity, during random access, the optical pickup is moved to the target track position on the disk, and at the same time the disk rotational speed (revolutions per second r, p, s) is changed. Regular disk rotation speed according to track position: This must be controlled, but conventionally, the rotation speed control method for this random access u, 'f does not take into account the difference in linear speed of individual disks, and The speed is assumed to be -f11 as 1,2 m/O. That is, the disk rotation 1 for each track position measured as a linear velocity of 1.2 w/s.
Read the disk rotation number 111t C1 at the target track position from the rotation speed control table stored in
The rotational speed of the disk was controlled as 0 with δ and the rotational speed of the disk with -C.

[Fixed Points to be Solved by the Invention] In the conventional search method described above, if the linear velocity of the disk is exactly 1.2 m10, the rotational speed of the disk at the read target track position (i.e., the control target rotational speed) matches the regular disc rotational speed that should actually be considered, so the actual disc rotational speed after the movement is controlled to the regular disc rotational speed in a short time, but if the disc is not 1.2m/”, In case j, the read disk rotation speed at the target track position is 4° from the normal disk rotation speed at the target position, so there is a deviation in the control target value itself, and for this reason, the disk rotation speed is actually normal. It took a long time to reach the disk rotation speed of It was causing an increase.

The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide an optical disk search method that can shorten access time.

Means for Solving Problem E The optical disc retrieval method of the present invention for solving the above problem α detects the actual linear velocity of the disc and
The disk rotation speed N corresponding to the horizontal track position 1°1t is read out from the rotation speed control table in which the disk rotation speed for each track position calculated using this disk actual linear velocity \I is stored, and search 11 is performed. The control target rotation speed at the target track position is set to be the control target rotation speed at the target track position.

[Effect 1] In the above search method, the disk rotation t number N read from the rotation speed control table at the time of search is calculated according to the actual line i of the disk, and is the normal rotation speed at the target trunk position. . In other words, the value of the control target rotational speed matches the actual disk rotational speed that should be achieved.

Therefore 1. Even when searching for discs with different speeds, rotational speed control is always performed based on the correct control target rotational speed. For this reason, all optical discs [
On the other hand, the number of disk rotations after the optical pickup is moved can be controlled to the normal number of disk rotations within a short range of n, 7, thereby shortening the access time.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a CD device according to an embodiment of the present invention.
is a spindle motor, 2 is a disk, 3 is a pickup, 4 is a reproduction signal amplifier, 5 is a Denotalui No. 3 processing circuit,
6 is a servo J processing circuit, and 7 is a system control circuit. 8 is an audio conversion processing circuit, which includes a digital filter 9, a digital/analog converter 10, and an audio circuit 1.
The 1st prize is poor in Ia. In the case of a CD-110M device, instead of the audio conversion processing circuit 8, a CD-ROM circuit 12 shown by a two-dot chain line is connected.

In the present invention, a linear velocity detection circuit 13 for detecting the actual FA velocity of the disk;
A linear velocity memory 14 for storing the actual linear velocity of the disk detected by , and the number of disk rotations for each track position (revolutions per second (r, p, s)) calculated from the actual linear velocity . It is equipped with a rotation speed control table 15 that stores the rotation speed.

The system control circuit 7 includes 70-- in FIG.
A rotation speed control program as shown in the chart is included.

In the above configuration, when starting the CDA device, the focus control is first turned on and the spindle motor 1 is rotated.
After performing various initializations, pickup 3 moves to the lead-in area on the inner circumference of the disc, and 7! is placed in the TOC (table on content) there. For example, when reading the TOC, the actual linear velocity of the disc is detected by the linear velocity detection circuit 13, and the detected actual linear velocity of the disc is stored in the linear velocity memory. 14. Note that there are various methods for detecting the actual linear velocity of the disc, and any method may be used.

Refer to chart 70 in Figure 2 for the disk direct transmission speed control procedure during random access. S1), waits for a search command (step S2), and when a search command is received, reads out the disk rotation speed N for the target track position from the rotation speed control table 15 (step S3).

Set the disc rotation speed N at the target track position! The rotation speed of the spindle motor 1 is controlled using the rotation speed that should be set to 2, that is, the control target rotation speed (step S4, step S5). , an example of closed loop control in which it is fed back is shown (step SS).

The disk rotation speed N read out from the rotation speed control table 15 in the third step of the disk rotation speed control is recalculated and set every time the disk is replaced, and is set correctly to the actual disk line jgL degrees ■. This is the normal rotational speed of the corresponding target track position. In other words, the value of the control target rotational speed matches the disk rotational speed that should actually be achieved. Therefore, even if you search for themes with different linear velocities,
The rotational speed is always controlled based on the correct control port (7 times 1), and the disk rotational speed after the optical pickup is moved is controlled to the normal disk rotational speed in a short time. The waiting time for controlling the rotational speed after the /upf hyperactivity is shortened, and the access time is shortened.

Note that the present invention is not limited to current CDVC devices and CD-ROM devices, but can be applied to other disk devices of the same standard as these.

[Effects of the Invention] As explained above, according to the search method of the present invention, changes in the actual linear velocity of the disk are detected, and the rotational speed of the disk for each track position calculated in n1M degrees is detected. Disk rotation speed Nf corresponding to one target track position from the rotation speed control table in which is stored:
Since this is the control target rotation speed at the target track position during reading and searching, the rotation speed is always controlled based on the correct control target rotation speed for all disks with different linear velocities. Therefore, the number of times it takes for the disk rotation speed to reach the normal rotation speed after moving the optical pickup! The number control waiting time is always the shortest,
Access time has been reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a CD device showing an embodiment of the present invention, and FIG. fjS2 is a flowchart showing a disk rotation speed control program when searching for an optical disk. 7... System control circuit, 13... Linear velocity detection circuit, 14... Linear velocity memory, 15... Rotation speed control table.

Claims (1)

[Claims] The actual linear velocity of the disk is detected, and the disk rotational speed N corresponding to the target track position is calculated from the rotational speed control table in which the disk rotational speed for each track position calculated using this disk actual linear velocity V is stored. An optical disc search method characterized in that the control target rotation speed is set at a target track position during reading and searching.