JP3538395B2 - Optical disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus, and more particularly to a technique related to kick control in an optical disk apparatus, that is, control for moving an objective lens of an optical pickup across a track in a radial direction of an optical disk to a desired track. It is about.

[0002]

2. Description of the Related Art When a kick command is generated, a tracking servo loop is opened, and a kick pulse having a polarity, a pulse width, and a pulse level according to a kick direction is generated.
The actuator is applied to the optical pickup driving actuator, and the actuator is driven to move the movable part of the optical pickup. Then, when the tracking error signal reaches a certain reference value beyond a certain prescribed track, a brake pulse having a pulse width and a pulse level necessary for applying a brake is applied to the actuator. With this, when the beam spot reaches the center of the track,
The tracking servo loop is closed, the servo is pulled in, and the kick ends.

In the kick control described above, conventionally, the maximum number of kicks that can be kicked at one time has been determined in advance according to the eccentricity standard of the disk.

[0004]

Strictly speaking, the optical disk is not a perfect circle but eccentric. In addition, a chucking error occurs when the optical disc is mounted. The greater the number of these eccentric components, the more errors in track landing due to eccentricity caused an error in the landing point when performing a large number of kicks, and it was necessary to perform the kick again, resulting in variations in access time. .

When a large number of kicks are performed with the objective lens tilted, a tracking error signal is not correctly output, and the kick often fails.

[0006] The present invention has been made in view of the above points,
The purpose is to enable correct kick control and shorten the access time. Another object of the present invention is to make it possible to speed up servo pull-in in kick control.

[0007]

In order to achieve the above object, an optical disk apparatus according to the present invention measures an eccentricity including a chucking error when mounting an optical disk,
The maximum number of kicks to be kicked at once according to the eccentric amount is determined from a table created in advance. In the case of a multiple kick, the kick is started at the moment when the objective lens of the optical pickup is right below the track and swings in the same direction as the kick movement direction.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a main configuration of an optical disk device according to an embodiment of the present invention. In FIG. 1, 1
Is a tracking error signal detected by the optical pickup, 2 is a phase compensation filter, 3 is a gain compensation filter,
Reference numeral 4 denotes an adder, and reference numeral 5 denotes a swing amount detection LPF (for example, fc = 1H) for detecting the swing amount of the optical pickup.
z) and 6 are TRL-SENSE output from LPF5
A signal (a swing amount detection signal) 7 is a moving direction detecting LPF (for example, a moving direction detecting LPF) for detecting the moving direction of the optical pickup.
fc = 200 Hz), 8 is TR output from LPF 7
-SENSE signal (moving direction detection signal), 9 is a tracking equalizer changeover switch, 10 is a tracking drive output output from the switch 9, 11 is a kick and brake pulse, 12 is a thread equalizer, 13 is a thread equalizer changeover switch, and 14 is a thread equalizer changeover switch. This is a thread drive output from the switch 13.

In the configuration shown in FIG. 1, a tracking error signal 1 detected by an optical pickup passes through a phase compensation filter 2 and a gain compensation filter 3 and is added by an adder 4. When the tracking servo is ON, the calculation result is used as the tracking drive output 10 as it is. When a kick is being performed, a kick pulse and a brake pulse 11 are generated and used as the tracking drive output 10.

Also, a phase compensation 2, a gain compensation filter 3
And the signals added by the adder 4 are also output to the head movement amount detection LPF 5 and the movement direction detection LPF 7, respectively, and the head movement amount detection LPF 5 outputs the TRL-S
The ENSE signal 6 is output, and the TR-SENSE signal 8 is output from the moving direction detecting LPF 7.

The signal passed through the gain compensation filter 3 becomes a thread input signal, and is output from the thread equalizer 12.
, And when the thread servo is turned on by the thread equalizer changeover switch 13, the operation result is directly used as the thread drive output 14. When a kick is being performed, “0” is set as the thread drive output 14.

Next, with reference to FIG. 2 and FIG. 3, the processing relating to the kick control of the present embodiment will be described.

First, the processing at the time of loading an optical disk is described in FIG.
It will be explained by. When the optical disk is mounted, the amount of eccentricity of the optical disk is detected including the chucking error (step S1). Next, a table created in advance that defines the relationship between the amount of eccentricity and the maximum number of kicks that can be kicked at one time (for example, if the amount of eccentricity is ± 20 μm or less, the maximum number of kicks is 20; A table in which the relationship between the amount of eccentricity and the maximum number of kicks that can be kicked at one time is stored in advance in an appropriate storage area of the microcomputer.
(Step S2), the maximum number of kicks corresponding to the detected eccentric amount is determined as the maximum number of kicks that can be kicked at one time (Step S3).

Next, the processing at the time of kick control will be described with reference to FIG. At the time of issuing a kick command, the microcomputer checks the maximum number of kicks determined as described above, and if the number of kicks desired exceeds the maximum number of kicks, controls the microcomputer to repeatedly perform kicks with the maximum number of kicks or less. (Step S11). Next, the number of kicks and the kick direction are obtained (S12), the tracking servo and the thread servo are turned off (step S13), and the kick start timing is waited.

It is presumed that the influence of lens shift and eccentricity is relatively small when a few kicks are kicked, and it is better to start the kick without waiting for the kick start timing, as described later, to shorten the kick time. It seems to be connected. Therefore, although not shown in FIG. 3, at the time of a few kicks, control is performed so that a kick is started immediately after step S13 (it should be understood that FIG. 3 is a processing flow in the case of a large number of kicks). . The branch point of the number of kicks dividing the kick procedure needs to be experimentally examined and determined to be a suitable value.

The processing flow of FIG. 3 is a processing flow in the case of a multiple kick. At the time of the multiple kick, in step S14 following step S13, it is determined that the objective lens of the optical pickup is right below the track of the optical disk. For confirmation, it is determined whether or not the TRL-SENSE signal 6 is substantially "0" (as shown in FIG. 4, it is determined whether or not the TRL-SENSE signal 6 has a value that can be regarded as substantially "0"). If YES, the process proceeds to step S15, and if NO, the process remains at step S14. In the step S15, it is determined whether or not the kick direction is the forward direction.
The process advances to step S16, and if NO, the process advances to step S18.

In step S16, which proceeds when the direction is forward, the process proceeds to step S17 after the TR-SENSE signal 8 becomes negative. In step S17,
The timing waits for the timing when the TR-SENSE signal changes from negative to positive (timing A in FIG. 4), and when this timing comes, the process proceeds to step S20. In step S18, which proceeds when the direction is the reverse direction, the process proceeds to step S19 after the TR-SENSE signal 8 becomes positive. In step S19, the process waits for a timing when the TR-SENSE signal changes from positive to negative (timing B in FIG. 4), and when this timing comes, the process proceeds to step S20.

In step S20, a kick start command is issued.
In the next step S21, kick processing for applying the kick pulse and brake pulse 11 to the tracking actuator is performed, and then, in step S22, the tracking servo and the thread servo are turned on, thereby ending the kick processing. .

That is, steps S14 to S20
As shown in (1), when a large number of kicks are kicked, the kick is started at the moment when the objective lens of the optical pickup is right below the track and swings in the same direction as the kick movement direction. Therefore, the transient operation at the start of the kick can be performed quickly and stably, so that the vibration of the objective lens can be suppressed as much as possible, and the servo pull-in can be accelerated.

[0021]

According to the first aspect of the invention, by measuring the amount of eccentricity, it is possible to set a suitable maximum number of kicks according to the amount of eccentricity, and it is possible to perform kick control correctly. In addition, the number of kicks that can be performed at one time can be greatly increased as compared with the case where the amount of eccentricity is almost at the limit of the standard range, so that the access time can be reduced.

According to the second aspect of the present invention, the maximum number of kicks can be uniquely determined according to the amount of eccentricity.
No extra circuitry is required.

According to the third aspect of the present invention, since the kick operation can be always performed in the same state, it is possible to suppress variations in kick.

According to the fourth aspect of the present invention, the kick is started in the same direction as the direction in which the objective lens swings.
The vibration of the objective lens can be suppressed, and the servo pull-in can be accelerated.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a main configuration of an optical disc device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of processing when an optical disk is mounted in the optical disk device according to one embodiment of the present invention.

FIG. 3 is a flowchart showing a flow of processing at the time of kick control in the optical disc device according to one embodiment of the present invention.

FIG. 4 is an explanatory diagram showing signal waveforms representing kick start timing and the like in the optical disc device according to one embodiment of the present invention.

[Explanation of symbols]

1 Tracking error signal 2 Phase compensation filter 3 Gain compensation filter 4 Adder 5 LPF for swing amount detection 6 TRL-SENSE signal 7 LPF for moving direction detection 8 TR-SENSE signal 9 Tracking equalizer changeover switch 10 Tracking drive output 11 kick, brake pulse 12 thread equalizer 13 Thread equalizer changeover switch 14 Thread drive output

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B ^7/ 08-7/085

Claims (4)

(57) [Claims] Means for detecting the amount of eccentricity of an optical disk;
Means for determining the maximum number of kicks in one operation based on the detected amount of eccentricity. 2. The optical disk device according to claim 1, further comprising a table of the maximum number of kicks at one time corresponding to the eccentric amount. 3. The method according to claim 1, further comprising: after confirming that the objective lens of the optical pickup is located immediately below the track on the optical disk, when a large number of kicks are performed.
An optical disc device for starting a kick. 4. The kick according to claim 3, wherein the kick is started when the objective lens of the optical pickup swings from directly below the track in the same direction as the moving direction according to the moving direction of the multiple kicks. Optical disk device.