JPH11213401A - Access control method for optical disk reproducing device and access control circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an access control method of an optical disk reproducing device and an access control device capable of performing the exact correcting of erroneous tracks every time of access control without using a ROM table or a large-capacity memory. SOLUTION: In the access control of an optical disk reproducing device reproducing recorded information on a spiral shaped track of an optical disk 1, this device is made so as to correct the number of erroneous tracks every revolution of the optical disk 1 by detecting the number of revolution of the disk 1 through a revolution detecting means 4, by correcting the number of track traverses of a pickup 2 while detecting how many times the disk 1 is revolved during the movement of the pickup at the time of the access control from the revolution detection signal through a remaining tracks correcting means 4 and by calculating the number (y) of remaing access tracks from the present track address of the pickup at the time of the access control to a target track address based on the track correcting signal through a remaining track calculating means 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an access control method and an access control circuit of an optical disk reproducing apparatus for reproducing information recorded on a spiral track formed on an optical disk including a magneto-optical disk by a pickup.

[0002]

2. Description of the Related Art Access control of an optical disk having spiral tracks is basically performed as follows.
The number of access tracks, which is the difference between the current track address and the target track address at the start of access control, is calculated by a computer counter. While moving the pickup in the tracking direction with respect to the rotating optical disc,
Detects the number of tracks traversed by the pickup. The number of tracks traversing the pickup is subtracted from the previously calculated number of access tracks to detect the number of remaining access tracks, and the pickup moving speed is controlled according to the number of remaining access tracks. When the number of remaining access tracks becomes zero, the pickup movement is stopped and the access control is terminated.

In access control of an optical disk having spiral tracks, a count error based on the pickup moving time and the optical disk rotation speed occurs in principle in the count value of the number of track crossings. That is, since the tracks of the optical disk are formed in a spiral shape,
One rotation of the optical disc with the pickup position fixed results in 1
It may be an illusion that the track crosses a track. In actual access control, if the pickup moves outward in the radial direction of the optical disk, a count error occurs in which the number of track traverses is increased by one. When the pickup moves inward in the direction, the number of truck traverses is 1
This causes a small count error.

Therefore, it is necessary to perform access control by correcting the number of track traverses during the movement of the pickup. As a method of correcting the number of error tracks due to the track count error, a ROM table (time table, speed table, etc.) of a computer is used. Or a track count correction method using a large-capacity memory. For example, the error track number of the track traversal number after the pickup movement at the time of the first access control is stored in the memory, and the number of access tracks from the current access address to the target access address of the track when newly performing access control is There is an access control method in which error track correction is performed by adding and subtracting the number of error tracks stored during the first access control (Japanese Patent Laid-Open No. Hei 4-305).
No. 823).

[0005]

However, according to the access control method for performing error track correction at the time of subsequent access control using the number of error tracks stored at the time of the first access control, accurate access track movement is performed at the time of the first access control. In addition, since the number of error tracks varies depending on the position of the pickup moving on the optical disk, the rotation speed of the optical disk, and the number of track traversals, an enormous amount of correction data is required to correct the number of error tracks. There was a problem that had to be stored in the memory of the capacity.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an access control method of an optical disk reproducing apparatus capable of accurately correcting an error track every time access control is performed without using a ROM table or a large-capacity memory. It is to provide a control device.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an optical disk reproducing apparatus for reproducing information recorded on a spiral track of an optical disk by a pickup in an optical disk during access control for moving the pickup in a tracking direction with respect to a rotating optical disk. Detect the rotation speed of
The object is achieved by determining how many rotations of the optical disk have been made during the movement of the pickup based on the rotation detection signal and correcting the number of tracks traversed by the pickup.

Further, the present invention relates to an optical disk reproducing apparatus for reproducing recorded information of a spiral track on an optical disk by a pickup, and a rotational speed of the optical disk during access control for moving the pickup in a tracking direction with respect to the rotating optical disk. Rotation detection means for detecting the number of rotations of the optical disk during the movement of the pickup during access control from the disk rotation detection signal of the rotation detection means, and a remaining track correction means for correcting the number of track traversal of the pickup, The above-mentioned object is achieved by providing a configuration including a remaining track calculating means for calculating the number of access tracks from the current track address of the pickup to the target track address at the time of access control based on the track correction signal of the remaining track correcting means. To achieve It is.

Here, as the rotation detecting means, means for optically directly or indirectly detecting the rotation angle of the optical disk, means for counting pulses generated by a spindle motor for rotating the optical disk, and the like are applied. . If such correction of the number of error tracks at the time of access control from the rotation speed of the optical disk is performed for each rotation of the optical disk, access control by linear correction independent of the position of the pickup on the optical disk can be performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.
Will be described with reference to the block diagram of FIG.

The optical disk reproducing apparatus shown in FIG. 1 rotates an optical disk 1 by a spindle motor 3 and
The access control circuit of the present invention incorporated in the optical disc reproducing apparatus includes a new circuit of the next rotation detecting means 4 and the remaining track correcting means 7. And the remaining track calculation means 8 using an existing circuit.

The pickup control unit 1 shown in FIG.
Numeral 0 controls the drive of the pickup 2 with respect to the optical disc 1 in the tracking direction, and is connected to the computer 9 and the track counter 11. The computer 9 outputs a pickup movement control signal to the pickup control unit 10 at the time of access control, and controls the movement speed of the pickup 2 in the tracking direction. Track counter 11
Counts how many tracks of the optical disk 1 the pickup 2 has traversed during access control, and outputs the counted number of track traversals x to the remaining track calculating means 8.

The rotation detecting means 4 detects the number of rotations of the optical disc 1 at the time of access control. For example, a spindle FG generating circuit 5 directly connected to the spindle motor 3
And its spindle FG pulse counter 6.
The remaining track correction means 7 detects how many rotations of the optical disk 1 have been made during the movement of the pickup during the access control from the disk rotation detection signal of the rotation detection means 4, and corrects the number x of tracks traversed by the pickup 2 to obtain the remaining track. It is a correction circuit that outputs to the calculation means 8. The remaining track calculating means 8 calculates the number y of access tracks from the current track address to the target track address of the pickup 2 at the time of access control based on the track correction signal from the remaining track correcting means 7 and outputs the calculated number to the computer 9. Next, an access control method of the present invention using the above-described access control circuit will be described with reference to the flowchart of FIG.

When an access command is issued in step S1, the process proceeds to step S2, where the remaining track calculating means 8 calculates the number y of access tracks from the current track address of the pickup 2 to the target track address, and based on the calculated value. Then, the computer 9 outputs a pickup moving speed signal or the like to the pickup control section 10, and the pickup movement in step S3 is started. At the same time, the rotation detecting means 4 detects the number of rotations of the optical disk 1, and the process proceeds to step S4.

In step S4, it is determined whether the optical disk 1 has made one rotation. If it is determined that the optical disk 1 has not made one rotation, the process proceeds to step S5. If it has been determined that it has made one rotation, the process skips step S5 and proceeds to step S6. Move to When the process proceeds from step S4 to step S5, the remaining track correction means 7 sets the number y of remaining access tracks to [y ± 1].
Is corrected by the following formula. That is, access control is started by rotation of the optical disk and movement of the pickup, and the optical disk 1
The rotation y of the pickup 2 is corrected every time the disk rotates once. This correction is made for pickup 2
Moves to the outside of the optical disc 1 in the radial direction, [y−
In [1], the movement inward in the radial direction is performed in [y + 1], and the corrected access track signal is input to the remaining track calculation means 8, and the number y of remaining access tracks is updated in step S6.

In step S6, the number of updated access tracks [y ← y−x] up to the target track address is calculated, and the flow advances to step S7. If it is determined in step S7 that the number y of remaining access tracks is zero (y = 0),
It is determined that the pickup 2 has reached the target track address, and the access control ends in step S8. In step S7, the number y of remaining access tracks is not zero (y ≠).
0), the process returns to step S4 and returns to step S4.
The above operations after 4 are repeated.

[0017]

As described above, according to the present invention, the correction of the count error at the time of crossing the track of the pickup which is inevitably generated in the access control of the optical disk having the spiral track is performed by correcting the data for this correction. Since the operation can be performed only by detecting the number of rotations of the optical disk and performing arithmetic processing without storing it in the memory, it is possible to perform access control by linear correction irrespective of the position of the pickup on the optical disk, facilitating faster access control. Will be able to

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a flowchart of the access control circuit of FIG. 1;

[Description of Signs] 1 optical disk 2 pickup 4 rotation detection means 7 remaining track correction means 8 remaining track calculation means

Claims (2)

[Claims] An optical disk reproducing apparatus for reproducing recorded information of a spiral track of an optical disk by a pickup detects a rotation number of the optical disk during access control for moving the pickup in a tracking direction with respect to a rotating optical disk. An access control method for an optical disk reproducing apparatus, wherein the number of rotations of an optical disk while the pickup is moving is determined based on a detection signal, and the number of track crossings of the pickup is corrected. 2. An optical disc reproducing apparatus for reproducing recorded information of a spiral track of an optical disc by a pickup, wherein a rotation detection for detecting a rotation number of the optical disc during access control for moving the pickup in a tracking direction with respect to a rotating optical disc. Means for detecting the number of rotations of the optical disk during the movement of the pickup during access control from the disk rotation detection signal of the rotation detection means, and correcting the number of traversing tracks of the pickup; and the remaining track correction means. An access control circuit for an optical disc reproducing apparatus, comprising: a remaining track calculating means for calculating the number of access tracks from the current track address of the pickup to the target track address at the time of access control based on the track correction signal of