JP2001014705A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make possible the execution of good tracking by previously recording the eccentric components corresponding to the rotating positions of a spindle motor and an optical disk in a memory and moving the optical head by reading out the eccentric components recorded in the memory at the time of recording and reproducing of the optical disk. SOLUTION: First, a control section 54 stops the operation of a feed forward(FF) signal forming section 53 and starts a tracking operation. Next, the control section 54 starts recording and reproducing operation after recording the track error signal which is the output of a BPF 51 corresponding to the rotating position detected by a rotating position detector 3 in the memory 52 via an I/O 55. The FF signal forming section 53 reads out the recording value of the memory 52 corresponding to the rotating position obtain through an I/O 57 from the rotating position detector 3 and drives a step motor 7 through an I/O 56 and a step motor drive section 9. As a result, the optical head 4 moves in correspondence to the eccentric components to allow the execution of the recording and reproducing to and from the optical disk 1 without errors.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device for recording and reproducing information on and from an optical disk, and more particularly to an optical disk device capable of performing good tracking.

[0002]

2. Description of the Related Art The configuration of a tracking control system of a conventional optical disk device will be described with reference to FIG. In FIG.
1 is an optical disk for recording and reproducing information, 2 is an optical disk 1
A rotary position detector for detecting the rotational position of the spindle motor 2; an optical head 4 for recording and reproducing information from the optical disk 1;
A tracking control circuit for causing the head to record and reproduce information on the optical disc 1; 6, a base on which an optical head is mounted; 7, a step motor;
Is a rotating column provided with a lead screw that rotates with the rotation of the optical disk 1 and moves the base 6 in the radial direction of the optical disk 1. Reference numeral 9 denotes a step motor drive unit that drives a step motor 7.

As shown in FIG. 7, light from a semiconductor laser light source 41 is converted into a parallel light by a collimating lens 42 and reaches an objective lens 44 via a beam splitter 43. The optical disc 1 is irradiated with the condensed beam condensed in the step (1).

[0004] The reflected light from the optical disk 1 is
4. The light receiving section 46 is condensed and irradiated through the beam splitter 43 and the detection lens 45. The output of the light receiving unit 46 is input to a track error (TE) signal generation unit 50 of the tracking control circuit 5, and a track error signal TE is output. The track error signal TE is input to the lens position control unit 47 and the objective lens 44 Is moved in the radial direction of the optical disc 1.

FIG. 8 shows a specific example of a track error signal generator. The light receiving section 46 is divided into four parts A, B, C and D in the radial direction of the optical disc 1 and in a direction orthogonal to the radial direction. In addition, a portion indicated by a circle indicates a spot of light that is condensed and irradiated via the detection lens 45.

The track error signal TE is obtained by
And D are added by an adder 50-1, B and C of the light receiving unit 46 are added by an adder 50-2, and the adder 50-2 is subtracted by the subtractor 50-3 from the output of the adder 50-1. As a result, a track error signal TE is obtained.

When the optical axis of the semiconductor laser light source 41 coincides with the optical axis of the objective lens 44, the spot of the reflected light applied to the light receiving section 46 irradiates the center of the light receiving section 46 as shown in FIG. . When the objective lens 44 moves to the left or right, the spot indicated by the circle also moves to the left or right.

When the center of the condensed beam that irradiates the optical disk 1 with the objective lens 44 irradiates the left or right of the center of the track for recording and reproducing information on the optical disk 1, the output of the adder 50-1 is output. 2, the track error signal TE output from the subtraction unit 50-3 is a positive or negative signal, and its value is proportional to a value far from the center of the track.

The tracks of the optical disk 1 are spiral, and the stepping motor driving section 9 sends a driving pulse to the stepping motor 7 based on the rotational position detected by the rotational position detector 3, as shown in FIG. The optical head 4 is moved by being sent out and rotated, and the condensed beam from the objective lens 44 is irradiated on the track.

In this case, when the condensed beam irradiates a position away from the center of the track, the aforementioned track error signal T
E is output, and the lens position control unit 47 moves the objective lens 44 to irradiate the center of the track by the output track error signal TE.

[0011]

When the optical disk 1 or a step motor for rotating the optical disk 1 is deviated from the axis, the track error signal TE generated by the track error signal generating section 50 is, as shown in FIG. Fluctuates greatly in the form of a sine wave with a cycle corresponding to the cycle of one rotation,
The lens position control unit 47 receives the track error signal T
Corresponding to E, the objective lens 44 is moved in a large sine wave shape to irradiate the center of the track with a condensed beam for tracking.

When the objective lens 44 largely moves as described above, the spot of the condensed beam indicated by a circle irradiating the light receiving section 46 shown in FIG. When the spot moves largely right and left, an offset output of a DC component corresponding to the movement of the spot is generated in the track error signal TE, and the occurrence of the offset causes an error in tracking, so that information can be recorded and reproduced without error. Did not.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical disk apparatus capable of performing good tracking by minimizing an optical axis shift even if an optical disk or a spindle motor for rotating the optical disk has an eccentricity.

[0014]

According to a first aspect of the present invention, an optical disk rotated by a spindle motor is irradiated with a condensed beam from an optical head, and the condensed beam is emitted in response to a track error signal generated from reflected light. A lens position controller for moving an objective lens for generating a light beam in the radial direction of the optical disc; and an optical head moving means for moving the optical head in the radial direction of the optical disc, wherein the optical head moving means corresponds to the rotation of the optical disc. An optical disk device which is moved and positioned on a track of an optical disk, a memory in which an eccentric component corresponding to the rotational position of the spindle motor is recorded in advance, and a rotational position detector for detecting the rotational position of the spindle motor. Recorded in the memory corresponding to the rotational position detected by the rotational position detector. Reads the core component, and a feedforward signal generation section for feedforward control is outputted to the optical head moving means.

According to a second aspect of the present invention, an optical disk rotated by a spindle motor is irradiated with a condensed beam from an optical head, and an object for generating the condensed beam in accordance with a track error signal generated from reflected light. A lens position control unit for moving a lens in a radial direction of the optical disc; and an optical head moving means for moving the optical head in a radial direction of the optical disc. In an optical disc device positioned at a track,
A rotational position detector for detecting a rotational position of the spindle motor, and an eccentric component recorded in the memory corresponding to the rotational position detected by the rotational position detector, and output to the optical head moving means. And a feedforward signal generator for performing feedforward control.

According to a third aspect of the present invention, an optical disk rotated by a spindle motor is irradiated with a condensed beam from an optical head, and an object for generating the condensed beam in accordance with a track error signal generated from reflected light. In an optical disc apparatus including a lens position control unit for moving a lens in a radial direction of the optical disc and an optical head moving unit for moving the optical head in a radial direction of the optical disc, a rotation position detector for detecting a rotation position of the spindle motor; A feedforward signal generation unit for reading out an eccentric component recorded in the memory corresponding to the rotation position detected by the rotation position detector, outputting the eccentricity component to the optical head moving means, and performing feedforward control.

According to a fourth aspect of the present invention, the rotation position of the recording data read from the memory by the feedforward signal generation unit is changed to the recording data of the rotation position before the time corresponding to the operation delay time of the optical head moving means. Is read. In the invention according to claim 5, the eccentricity of the optical disk is recorded in addition to the eccentricity component recorded in the memory in addition to the eccentricity of the spindle motor.

According to a sixth aspect of the present invention, the recording of the eccentric component in the memory is recorded at the start of the recording / reproducing operation of the optical disk. In the invention according to claim 7, an eccentric component recorded in the memory is an AC component of the track error signal.

In the invention of claim 8, the eccentric component to be recorded in the memory is a component from which noise of the track error signal has been removed. According to the ninth aspect of the present invention, the optical head moving means is moved by meshing with the lead screw provided with a stepping motor, a lead screw rotating with the rotation of the stepping motor, and the lead screw. And a base on which the optical head is mounted.

According to a tenth aspect of the present invention, the frequency of the drive pulse for driving the step motor is made not to coincide with the primary or higher order resonance frequency of the objective lens including the lens position controller. Further, in the invention according to claim 11, the natural frequency of the objective lens including the lens position control unit is set so as not to coincide with the frequency of the eccentric component recorded in the memory.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention are shown in FIGS.
This will be described with reference to FIG. FIG. 1 is a block diagram of a first embodiment of the present invention, and FIG. 2 is an operation flowchart of the first embodiment. In FIG. 1, 1 is an optical disk, 2 is a spindle motor,
Reference numeral 3 denotes a rotational position detector, 4 denotes an optical head, 6 denotes a base, 7 denotes a step motor, 8 denotes a rotating column, and 9 denotes a step motor drive unit, which are as described with reference to FIG.

Reference numeral 50 denotes a track error (TE) signal generation unit as described with reference to FIG. In the first embodiment, in addition to the conventional example, a band-pass filter (BP)
F) 51, memory 52, feedforward (FF) signal generation unit 53, control unit 54, interface (I / O)
55, 56, 57 and a processor (CPU) 58 are added.

The BPF 51 passes the eccentric component of the track error signal TE shown in FIG.
The output of the I / O 56 is connected to the step motor drive unit 9. Also, the rotation position output from the rotation position detector 3 via the I / O 57 is fetched.

Next, the operation of the embodiment will be described with reference to FIG. When the optical disk 1 is loaded and the operation of recording and reproducing information on the optical disk 1 is started, first, in step S1
Is performed. In step S1, the control unit 54
The operation of the FF signal generation unit 53 is stopped, and the process proceeds to step S2 to start the same tracking operation as usual.

In step S3, the control unit 54 controls the BP corresponding to the rotational position detected and output by the rotational position detector 3.
The AC component (eccentric component) of the track error signal TE output from F51 is taken in the I / O 55 and recorded in the memory 52. When the recording in the memory 52 is completed, the process proceeds to step S4, and the recording and reproducing operation is started.

In step S5, the FF signal generator 53
Represents the rotational position output from the rotational position detector 3 as an I / O 57
The process proceeds to step S7 to fetch the recorded value stored in the memory 52 corresponding to the fetched rotation position, and proceeds to step S8 to output the value to the step motor drive unit 9 via the I / O 56.

The step motor drive section 9 rotates the step motor 7 by adding a signal output via the I / O 56 in addition to following the normal track described in the conventional example. As a result, since the optical head 4 moves in accordance with the eccentric component, as shown in FIG. 3, the output from the track error signal generation unit 50 has a smaller amplitude of the eccentric component, and the optical axis shift is smaller. It is small, good tracking can be performed, and information can be recorded and reproduced accurately.

In this embodiment, the recorded value in the memory 52 corresponding to the rotational position output from the rotational position detector 3 is read out in step S7 and output to the step motor drive section 9. If there is a delay in the operation due to the above, the recording data at the rotational position before the time corresponding to the delay time may be read and output.

In the embodiment, as described in steps S1 to S3, at the start of the recording / reproducing operation, the eccentricity of the optical disk to be used and the eccentricity of the rotation axis for rotating the optical disk are added. Although the components are recorded in the memory 52, the eccentricity of the rotation axis may be measured at the time of product shipment and recorded in the memory 52, and steps S1 to S3 may be removed during recording and reproduction.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a configuration diagram of a second embodiment of the present invention. The second embodiment shown in FIG. 4 is different from the first embodiment shown in FIG.
The difference from the second embodiment is that in the first embodiment, the movement of the optical head 4 is based on the open loop control for moving the optical head 4 based on the rotation position outputted from the rotation position detector 3.

However, in the second embodiment, a DC component is extracted from the track error signal TE output from the track error signal generation section 50 via a low-pass filter (LPF) 61 and output from the I / O 50. Adder 6 with eccentric component
2 and the result is input to the step motor drive unit 9 to control the step motor 7 in a closed loop. By doing so, the configuration of the step motor drive unit 9 can be simplified.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a configuration diagram of a third embodiment of the present invention. The third embodiment shown in FIG. 5 corresponds to the first embodiment shown in FIG.
The difference from the first embodiment is that the optical head 4 is moved based on the rotation position output from the rotation position detector 3 in the first embodiment.

However, in the third embodiment, as shown in FIG. 5, the track error signal T output from the track error signal generator 50 using a low-pass filter (LPF) 63.
E removes noise and higher-order components contained in E, passes a DC component and an eccentric component, records it in the memory 52, reads out a DC component + eccentric component recorded in the memory 52 at the time of recording and reproduction, and reads the DC component and the eccentric component. Input to the control unit 9 to move the step motor 7.

Although the optical head 4 is moved by the stepping motor 7 and the rotating column provided with the lead screw in the embodiment, a linear motor or a DC motor may be used instead of the stepping motor. Alternatively, the optical head 4 may be moved using other means.

In order to move the optical head 4 with high accuracy, it is necessary to reduce the rotation angle of the step motor 2 by one driving pulse and to transmit the driving pulse at a high speed. However, the objective lens 44 and the lens position controller 4
In the case where the primary or higher order frequency of the resonance frequency including the drive frequency 7 and the frequency of the drive pulse to the step motor 7 match, the rotation angle per drive pulse of the step motor 7 is changed to change the frequency of the drive pulse. Change away from it.

Further, the natural frequency is changed by changing the mass or the rigidity of the resonance frequency including the objective lens 44 and the lens position controller 47 without changing the frequency of the drive pulse.

[0037]

An eccentric component corresponding to the rotational position of the spindle motor and the optical disk is recorded in advance in the memory, and the eccentric component recorded in the memory is read out at the time of recording / reproducing of the optical disk and input to the optical head moving means. Since the head is moved, the displacement between the optical axis of the objective lens and the optical axis of the laser beam is reduced, good tracking can be performed, and recording and reproduction on the optical disk can be performed without error.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is an operation flowchart of the embodiment.

FIG. 3 shows a track error signal (optical axis shift) according to the embodiment.
FIG.

FIG. 4 is a configuration diagram of a second embodiment of the present invention.

FIG. 5 is a configuration diagram of a third embodiment of the present invention.

FIG. 6 is a configuration diagram of a tracking control system of a conventional optical disk device.

FIG. 7 is a configuration diagram of an optical head and a tracking control circuit.

FIG. 8 is a specific example of a track error signal generation unit.

FIG. 9 is an explanatory diagram of a track error signal (optical axis shift) of a conventional example.

[Explanation of symbols]

 Reference Signs List 1 optical disk 2 spindle motor 3 rotation position detector 4 optical head 5 tracking control circuit 6 base 7 step motor 8 rotation column 9 step motor drive unit 41 semiconductor laser light source 42 collimator lens 43 beam splitter 44 objective lens 45 detection lens 46 light receiving unit 47 lens position control unit 50 track error signal generation unit 51 band pass filter (BPF) 52 memory 53 feed forward signal generation unit 54 control unit 55, 56, 57 interface (I / O) 58 processor (CPU) 61, 62 low Bandpass filter

Continued on front page F term (reference) 5D066 AA03 FA01 FA02 5D096 AA05 CC05 DD01 DD02 FF01 HH02 KK01 5D117 AA02 BB04 EE27 EE29 FF21 FF25 FF27 FF28 FX06 GG05 JJ06 JJ10 5D118 AA13 AA19 CD01

Claims (11)

[Claims] 1. An optical disk rotated by a spindle motor is irradiated with a condensed beam from an optical head, and an objective lens for generating the condensed beam in a radial direction of the optical disk in response to a track error signal generated from reflected light. The optical head moving means for moving the optical head in the radial direction of the optical disc, and moving the optical head moving means in accordance with the rotation of the optical disc so as to be positioned on the track of the optical disc. A memory in which an eccentric component corresponding to the rotational position of the spindle motor is recorded in advance, a rotational position detector for detecting the rotational position of the spindle motor, and a rotational position detected by the rotational position detector Read out the eccentricity component recorded in the memory corresponding to An optical disc device comprising: a feedforward signal generation unit that performs output and feedforward control. 2. An optical disc rotated by a spindle motor is irradiated with a condensed beam from an optical head, and an objective lens for generating the condensed beam corresponding to a track error signal generated from reflected light is moved in a radial direction of the optical disc. The optical head moving means for moving the optical head in the radial direction of the optical disc, and inputting the DC component of the track error signal to the optical head moving means to position the optical head on the track of the optical disc. A rotation position detector for detecting a rotation position of the spindle motor; reading an eccentric component recorded in the memory corresponding to the rotation position detected by the rotation position detector; And a feed-forward signal generator for performing feed-forward control by outputting the Optical disc apparatus characterized by a. 3. An optical disk rotated by a spindle motor is irradiated with a condensed beam from an optical head, and an objective lens for generating the condensed beam corresponding to a track error signal generated from reflected light is moved in a radial direction of the optical disk. An optical head device including a lens position control unit for moving the optical head in a radial direction of the optical disk, a rotation position detector for detecting a rotation position of the spindle motor, and a rotation position detector. An optical disk comprising: a feedforward signal generation unit that reads an eccentric component recorded in the memory corresponding to the detected rotational position, outputs the eccentric component to the optical head moving unit, and performs feedforward control. apparatus. 4. The recording apparatus according to claim 1, wherein the feedforward signal generating section reads out the recording data at a rotation position before the rotation position of the recording data read from the memory before a time corresponding to the operation delay time of the optical head moving means. 4. The optical disk device according to claim 1, wherein 5. The eccentric component of the optical disk in addition to the eccentric component of the spindle motor to be recorded in the memory.
The optical disk device according to 3 or 4. 6. The optical disk device according to claim 1, wherein the recording of the eccentric component in said memory is performed at the start of the recording / reproducing operation of said optical disk. 7. The optical disk device according to claim 1, wherein the eccentric component recorded in the memory is an AC component of the track error signal. 8. The optical disk apparatus according to claim 3, wherein the eccentric component recorded in the memory is a component from which noise of the track error signal has been removed. 9. A stepping motor for moving the optical head, a rotating column provided with a lead screw rotating with the rotation of the stepping motor, and the light moving by meshing with the lead screw of the rotating column. 2. The base according to claim 1, wherein said base is provided with a head.
The optical disk device according to 2, 3, 4, 5, 6, 7, or 8. 10. The apparatus according to claim 9, wherein a frequency of a drive pulse for driving said step motor does not coincide with a first-order or higher-order resonance frequency of said objective lens including said lens position control unit. Optical disk device. 11. The apparatus according to claim 1, wherein a natural frequency of said objective lens including said lens position control unit does not match a frequency of an eccentric component recorded in said memory. , 4,5,6,7,8,9 or 10
An optical disk device as described in the above.