JPH0268727A - Optical disk device - Google Patents

Abstract

PURPOSE:To stabilize a track jump control by measuring the eccentric accelera tion (driving current) of a track jump position with an eccentric acceleration correcting means and correcting the driving current of the track jump according to the eccentric acceleration. CONSTITUTION:In an optical disk device equipped with a light pick-up part 10, driving parts 12 and 14, an actuator 15 and a control part 17 for a track jump, an optical disk 1 is mounted, and a focus action and a tracking action are stabilized. Thereafter, based on a driving current S14 for tracking outputted from the driving part 14, the eccentric acceleration in the track jump position is detected, and according to the eccentric acceleration, the driving current for the track jump is corrected by eccentric acceleration correcting means 18 and 17. For such a reason, the influence of the eccentric acceleration is offset. Thus, the track jump action can be stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides an optical disc device, particularly an optical pickup.
? - Track jump control method for stably performing track jumps for rack movement % type % (Conventional technology) Conventionally, as a technology in this field, Kazuo Terada's ``Key Points of Optical Pickup System Design, 1, [6] (Sho 5
9-10-31>Japan Industrial Technology Center, P, 1.51
, 152, 161.

As described in this document, conventional optical disc devices irradiate a light beam onto an optical disc and detect focus errors (focusing errors) and tracking errors (trace errors with respect to tracks on the optical disc) from the reflected light. an optical pickup unit that outputs a focus error signal and a tracking error signal, a drive unit that outputs a focus drive current and a tracking drive current based on the focus error signal and the tracking error signal, and the focus drive current and an actuator that moves the optical pickup section in the focusing direction and the tracking direction using a tracking drive current.

In this optical disc device, for example, a spindle motor rotates the optical disc, and a drive unit moves the optical pickup unit in a focusing direction and a tracking direction via an actuator based on a focus error signal and a tracking error signal output from the optical pickup. Feedback control (servo) is performed to eliminate focus errors and tracking errors, and information on the optical disc is read.

Here, as shown in FIG. 2, an optical disc 1. Since the track 1a has a spiral shape from the inner circumference to the outer circumference, when the optical pickup section follows the track 1a, the optical pickup section moves toward the outer circumference side every rotation of the optical disc 1. This inconvenience arises. Therefore, in order to keep the optical pickup section on a constant track, an l-rack jump or 1lJrn is performed in which the optical pickup section jumps one track toward the inner circumference of the optical disk 1 every time the optical disk 1 rotates.

In order to perform this trap jump control, a control section is provided which causes the drive section to output a track jump drive current to the actuator based on track jump position information for each track that is not detected by the signal detection processing section. For example, if one track is divided into 17 sectors, the signal detection processing unit reads sector number information that has been formatted in advance on the optical disc for each sector.
By doing this, when 17 sectors are detected, the control section causes the optical pickup section to jump one track in the inner circumferential direction. The jump procedure is such that when the signal detection processing section detects sector 17, the control section stops the tracking operation, and the actuator is driven with a predetermined drive current and drive time to perform the track jump operation. .

(Problems to be Solved by the Invention) However, the apparatus with the above configuration has the following problems.

The optical disc 1 is rotated at 900 rpm by a spindle motor etc.
m, 1800 r p m to 2400 r'pm, 36
If the rotation speed is increased to 00 rpm, etc., the eccentricity of the optical disk due to the center hole eccentricity and track eccentricity of the optical disk, and the eccentric acceleration due to the misalignment of the rotation axis of the spindle motor will increase, and when the focus and tracking servo is turned on, this The disturbance of eccentric acceleration disturbs the servo, preventing a stable I-rack jump operation, and it takes time for a stable tracking operation to occur after a track jump. Furthermore, in the worst case, there is a risk that the actuator will cause the optical pickup section to run out of control, and it has been difficult to prevent this.

The present invention provides an optical disc device that solves the problem of the prior art in that the track jump operation becomes unstable due to eccentric acceleration.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides an optical disc device equipped with an optical pickup section, a drive section, an actuator, and a track jump control section. After the I-racking operation is stabilized, the steel core acceleration at the track jump position is detected based on the tracking drive current output from the drive unit, and the ?-rack jump drive current is corrected according to the eccentric acceleration. This is provided with eccentric acceleration correction means.

(Function) According to the present invention, since the optical disc device is configured as described above, the eccentric acceleration correction means detects the tracking drive current at the track jump position after the optical disc is mounted and the servo is stabilized. The eccentric acceleration is determined and the track jump drive current is corrected according to the eccentric acceleration, thereby working to cancel out the effects of face center acceleration. Therefore, the above problem can be solved.

(Embodiment) FIG. 1 is a schematic block diagram of an optical disc device showing an embodiment of the present invention.

This optical disc device has an optical pickup section 10 configured using, for example, the astigmatism method or the knife method described in the above-mentioned document. This optical pickup section 10
includes a semiconductor laser as a light source, an objective lens, a mirror,
It irradiates the optical disc 11 in FIG. 2 with a light beam, detects focus errors and tracking errors from the reflected light, and outputs a focus error signal 510a and a tracking error signal 510b. , a signal 5 containing address information formatted in advance on the optical disc 1.
It has a function of outputting 10c.

Optical pickup unit] 0 includes a focus phase compensation unit 11
and a focus drive section 12 are connected, and a tracking phase compensation section 13 and a tracking drive section 14 are also connected, and an actuator 15 is connected to the output sides of the focus drive section 12 and tracking drive section 14. The focus phase compensation unit 11 has a function of performing phase compensation for focus servo on the focus error signal 510a. The focus drive section 12 has a function of generating a drive current S12 in the focus direction (optical disk direction) according to the output of the focus phase compensation section 11, and is composed of an amplifier and the like. The tracking phase compensation unit 13 has a function of performing phase compensation for tracking servo on the tracking error signal 510b. The tracking drive section 14 has a function of outputting a drive current S14 in the tracking direction (radial direction of the optical disk) according to the output of the tracking phase compensation section 13, and is composed of an amplifier and the like.

The actuator 15 includes the entire optical pickup section 10,
Alternatively, it has a function of mounting a part thereof and moving the 1ζ optical pickup section 10 in the focusing direction and the tracking direction using the drive current S12, 813. Then, an optical pickup section 10, a focus phase compensation section 11,
The focus drive section 12 and the actuator 15 constitute a focus servo f*rM, and the optical pickup section 10, the tracking phase compensation section 13, the tracking drive section 14, and the actuator 15 constitute a tracking servo 14''A.

Further, a signal detection processing section 16 and a control section 1-7 are connected to the optical pickup section 10, and the input sides of a focus drive section 12 and a tracking drive section 14 are connected to the output side of the control section 17. The output side of 14 is connected to the input side of control section 17 via eccentric acceleration extraction section 18 . The signal detection processing unit 16 has a function of extracting the address information formatted in advance on the optical disc L shown in FIG. have. The control section 17 has a function of controlling the focus drive section 12 and the tracking drive section 14 based on the outputs of the signal detection processing section 16 and the eccentric acceleration extraction section 18, and is composed of a control circuit and an arithmetic circuit. The eccentric acceleration extraction unit 18 has a function of inputting the drive current SL4 output from the tracking drive unit 14, detecting the direction and magnitude of eccentric acceleration proportional to the drive current SL4, and providing the detection signal to the control unit 17. It consists of analog/digital converters, etc. The eccentric acceleration extraction section 18 and the control section 17 constitute eccentric acceleration correction means. The eccentric acceleration correction means detects the eccentric acceleration at the track jump position based on the drive current S14, and adjusts the eccentric acceleration by 1 in accordance with the eccentric acceleration.
Drive current during rack jump operation (hereinafter referred to as 31
4a).

The operation of the optical disc device configured as above will be explained.

First, a normal servo state in which data can be read will be explained.

When the optical disc 1 shown in FIG. 2 is rotated by a spindle motor or the like, the optical pickup section 10 generates a focus error signal 510a and a tracking error signal 5 for the track 1a.
tob and a signal 510c. Then, the focus error signal SI Oa becomes 1. The phase of the signal is compensated by the focus phase compensator 11 and provided to the focus driver 12 .

The focus drive section 12 generates a drive current SL2 based on the output of the focus phase compensation section 11, moves the optical pickup section 10 in the focusing direction via the actuator 15, and performs focusing. Next, the tracking error signal 510b is transmitted to the tracking phase compensator 13.
The phase of the signal is compensated for by 1, and the signal is applied to the tracking drive unit 14.

The tracking drive unit 14 includes the tracking phase compensation unit 1
Based on the output of step 3, a drive current S14 is generated, and the optical pickup section 10 is moved in the tracking direction via the actuator 15 to trace the l-rack 1a. This makes it possible to read data from the track 1a.

Next, the track jump operation will be explained with reference to FIGS. 3 and 4. 3 is an explanatory diagram of the track jump operation in FIG. 1, and FIG. 4 is an eccentric acceleration distribution diagram of one rotation of the optical disc 1 in FIG. 2.

In FIG. 3, when the signal detection processing unit 16 detects a sector address (hereinafter referred to as a jump sector), for example 17 sector, where the track jumps every rotation based on the output signal -810c of the optical pickup unit 10, the signal detection processing unit 16 receives the detection signal. is given to the control section 17. Then, the control unit 17 controls the tracking drive unit 14 to perform a track jump, and turns the tracking servo on (low level, hereinafter referred to as 1).
1+L jl) and the direction in which the inner hair actuator 15 of the optical disc 1 is moved (positive direction).
A drive current 514a having a current value 11 and a time t1 is outputted from the tracking drive unit 14. This drive current 514a causes the actuator 15 to move the optical pickup section 10 one track toward the inner circumference. Next, the control unit 17 causes the tracking drive unit 14 to output a negative drive current 514a having a current value of 12 and a time t2, and stops the actuator 15. After that, the control unit 17 controls the tracking drive unit 14 to turn the tracking servo on (high level, hereinafter referred to as 'Topa').This causes the normal servo state and a state in which data reading is possible. becomes.

In addition, time 1.1 in FIG. t2 is appropriately selected in consideration of the gain of the tracking servo (total gain including the gain of the actuator 15), the weight and friction of the actuator 15, and the like.

Here, the operation of the eccentric acceleration extraction section 18, which is a feature of this embodiment, will be explained.

Eccentric acceleration is, for example, as shown in FIG.
This distribution is proportional to the drive current S14 during tracking. This distribution differs depending on the optical disc 1 mounted, and its size also changes. Furthermore, the distribution also changes depending on the position of the optical disc 1 when it is loaded. Therefore, after loading the optical disc 1, a focus search is performed, the focus servo is turned on, and then the tracking drive current is By sampling S14 at the timing of jump sector detection, the direction and magnitude of the concentric acceleration are measured.

Let the value of this eccentric acceleration be Δi. If the child direction is the outer circumferential direction of the optical disc 1, and one direction is the inner circumferential direction, then the timing of the jump sector is 1 in the outer circumferential direction when it is in the child direction.
This means that shoulder center acceleration is working. Therefore, the control unit 17 uses the drive current i1. The value of i2 is calculated and corrected according to the following equation.

i 1 = i 1 + Δα ... (], > 12 = i 2 - Δα When the control unit 17 corrects the drive current 11°12 based on equation (1), the influence of eccentric acceleration is canceled, and even during high-speed rotation, eccentricity does not occur. A stable track jump will be performed without being affected by acceleration.

Note that the present invention is not limited to the illustrated embodiment, and various modifications are possible. Examples of such modifications include the following.

In the above embodiment, the control phloem 17 and the eccentric acceleration extraction unit 18
The drive current i1. of FIG. Although the value of i2 was corrected, instead of the value of il and i2, the value of time t1. Even if the value of t2 or the values of 1lXtl and 12Xt2 are corrected, substantially the same advantages as in the above embodiment can be obtained.

(Effects of the Invention) As described in detail above, according to the present invention, the eccentric acceleration correction means measures the eccentric acceleration (drive current) at the track jump position (jump sector), and adjusts the Since the jump drive current is corrected, stable track jump control can be performed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the configuration of an optical disc device showing an embodiment of the present invention, Fig. 2 is a diagram showing the track shape of an optical disc, Fig. 3 is an explanatory diagram of the track jump operation in Fig. 1, and Fig. 4 is an optical disc FIG. 2 is an eccentric acceleration distribution diagram for one rotation of FIG. 1... Optical disc, 10... Optical pickup section, 11... Focus phase complement 1 prize section,
13... Tracking phase compensation section, 14...
... Tracking drive section, 15 ... Actuator, 16 ... Signal detection processing section, 17 ...
. . . control unit, 18 . . . eccentric acceleration extraction unit.

Claims (1)

[Scope of Claims] An optical pickup unit that irradiates a light beam onto an optical disk, detects a focus error and a tracking error from the reflected light, and outputs a focus error signal and a tracking error signal, and an optical pickup unit that outputs a focus error signal and a tracking error signal; a drive unit that outputs a focus drive current and a tracking drive current based on a signal; an actuator that moves the optical pickup unit in the focus direction and the tracking direction using the focus drive current and the tracking drive current; and the signal detection process. an optical disc device comprising: a control unit that outputs a track jump drive current from the drive unit to the actuator based on track jump position information for each track detected by the unit; After the operation is stabilized, eccentric acceleration correction means is provided for detecting eccentric acceleration at the tracking jump position based on the tracking drive current and correcting the track jump drive current according to the eccentric acceleration. optical disk device.