JPH08273174A - Optical disk device - Google Patents

Abstract

PURPOSE: To eliminate the variation of track error signals at the position of a disk due to various primary factors by measuring an amplitude value of the track error signal during the seek operation and providing a means for setting the optimum tracking gain and offset value based on the measured amplitude value. CONSTITUTION: In this optical disk device 1, an optical disk is irradiated with a luminous flux emitted from a semiconductor laser, and the reflected light is detected to detect a reproduced signal, track error signal, focus error signal, etc. These detected signals are amplified by an amplifier 2, then converted into digital signals by an analog-digital converter 3 and inputted to a digital signal processor 4. The signals are subjected to specified process by the processor 4 and outputted. The track error signal and the focus error signal among the outputted signals are amplified by an amplifier 5 nd inputted to an objective lens actuator 6 to execute the tracking control and focusing control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk drive apparatus, and more particularly to an optical disk apparatus capable of setting optimum servo loop gain and offset value in tracking control.

[0002]

2. Description of the Related Art As a conventional technique, for example, Japanese Patent Application Laid-Open No. 4-95.
There is one disclosed in Japanese Patent No. 231. That is, an optical head having a photodetecting means for detecting the position of a light spot with respect to a track of a disk, a tracking error signal generating means for generating a tracking error signal based on a detection value of the photodetecting means, and the tracking error signal. Is a control device having a phase compensating means for compensating the phase of the signal, and a driving means for moving the lens of the optical head in the radial direction based on the phase-compensated signal, the direct current included in the tracking error signal. Based on the detection means for detecting the component and the detection value detected by this detection means, an offset giving means for giving an offset for correcting the fluctuation of the direct current level of the tracking error signal caused by the warp of the disk to the tracking error signal A tracking control device is described having

[0003]

However, this tracking error signal varies due to various factors. Therefore, in the above tracking control device, it is possible to prevent the fluctuation of the DC level of the track error signal due to the warp of the disk obtained through the injection molding process or the like. However, there is a problem in that it cannot be prevented. Further, if the variation of the tracking error signal is large, the servo band becomes high, the rigidity of the optical pickup needs to be increased, and the cost is increased. To further reduce the variation, the precision of the drive mechanism parts and the mounting precision are increased. There is also a problem that it is necessary and the cost is increased.

The present invention has been made in order to solve the above problems, and electrically measures the variation of the tracking error signal due to various factors, sets the optimum servo loop gain and offset value, and changes the variation. It is an object of the present invention to provide a downsized device.

[0005]

According to the present invention, in order to achieve the above object, the position of a light spot with respect to a track of an optical disc is detected to generate a tracking error signal, and the track error signal is used to generate a lens of an optical head. In an optical disk device that performs tracking control by moving a position in the radial direction, the amplitude value of the track error signal is measured during a seek operation, and setting is made to set an optimum tracking gain and offset value based on the measured amplitude value. An optical disk device comprising means. The setting means sets an optimum tracking gain and offset value based on the amplitude value in the final section of the seek operation, and outputs the focus error signal when the spot crosses the track during the seek operation at the zero cross point of the track error signal. It has a focus control means for ringing and performing focusing control. Further, in an optical disc device for performing tracking servo correction for detecting a position of an optical spot with respect to a track of an optical disc, generating a tracking error signal, and moving a lens position of an optical head in a radial direction by the track error signal to perform tracking control An optical disk device comprising a setting means for measuring an amplitude value of a track error signal during a track jump operation and setting an optimum tracking gain and offset value based on the measured amplitude value.

[0006]

In the optical disk device according to the present invention, the
The tracking gain and the offset value are determined based on the amplitude value of the track error signal measured during the seek period, and the track error signal becomes stable. If this measurement is performed in the final section of the seek, the track error signal becomes more stable. Also, during seek operation, the focus error signal is sampled at the zero-cross point of the tracking error signal, and the focus is controlled by the optimum focus error signal.
A track error signal without deterioration is detected. further,
The tracking gain and the offset value are determined based on the amplitude value of the track error signal measured during the track jump operation, and the track error signal becomes stable.

[0007]

EXAMPLES The present invention will be specifically described below with reference to examples. FIG. 1 is a schematic block diagram of an optical disc device according to an embodiment of the present invention, in which an optical pickup device 1 illuminates an optical disc with a light beam emitted from a semiconductor laser and detects the reflected light. A reproduction signal, a track error signal, a focus error signal, etc. are detected. These detected signals are amplified by the amplifier (AMP) 2, and then the signals are converted into digital signals by the analog-digital converter (A / D converter) 3.
It is input to the digital signal processor (DSP) 4. The digital signal processor 4 performs a predetermined process on the signal and outputs it. Of the output signals, the track error signal and the focus error signal are amplified by the amplifier (AMP) 5 and input to the objective lens actuator 6 in the optical pickup device, and tracking control and focusing control are performed.

The optical pickup device 1 has an optical system that guides the light flux emitted from the semiconductor laser to the optical disc and guides the light reflected by the optical disc to each detector, and also moves in the radial direction of the disc. It is configured so that it moves in the radial direction of the disk during seek operation. The amplifier 2 is for amplifying the signal output from each detector, and the A / D converter 3
Is for converting the amplified signal into a digital signal. The DSP 4 is for performing predetermined arithmetic processing based on the digital signal output from the A / D converter 3 and outputting various signals, and the amplifier 5 outputs the signal output from the DSP 4. It is for amplification. The objective lens actuator 6 is for moving the objective lens in the tracking direction and the focusing direction based on the signal output from the amplifier 5, specifically, the track error signal and the focus error signal.

Next, the operation of determining the tracking servo gain and the offset value by this apparatus will be described. FIG. 2 is an explanatory diagram showing a tracking error signal in the case of seeking from the radial position X to Y of the disk for tracking, and the tracking servo is performed so that the tracking error signal (TE) = a in the section A before the seek operation is started. The tracking servo is turned on in the section B
FF, a tracking error signal when the optical pickup device 1 is moving is shown, a section C shows a TE signal when the target position Y is reached, and a section D shows a target position Y.
Shows the state in which the tracking servo is turned on after reaching. In this embodiment, when the section C is reached during the seek operation, the DSP 4 measures the positive peak value c and the negative peak value d of the track error signal, and d = (b +
c) / 2 is calculated to determine the offset value of the track error signal. Also, the calculation of (c-b) / 2 is performed,
Find the variation with respect to the target amplitude and multiply it by the reciprocal, for example, 2 /
If it is tripled, the offset value and the servo gain are determined and set so that the harp gain of the tracking servo becomes 3/2 times. Then, the tracking servo is turned on, and information is recorded or reproduced on the track.

FIG. 3 shows the focus error signal during the seek operation, and the dotted line in the figure shows the focus error signal of the conventional example. When the track is traversed, the signal received by the land portion between the tracks is When riding, the average value of the focus error signal rises. Therefore, an offset occurs during the operation of the focus servo, and the track error signal deteriorates due to the offset. Therefore, in this embodiment, the focus error signal is sampled at the positive zero-cross point of the track error signal (pointed by the arrow in the figure), and this sampled focus error signal is not affected by the land, and optimum focus control is performed. Made, and thus
A track error signal without deterioration can be obtained. The focus servo can be implemented with the same configuration as that shown in FIG.

FIG. 4 is a diagram showing a track error signal during a track jump operation, and specifically shows a track error signal when jumping from the outside to the inside and when jumping from the inside to the outside. A when jumping inward
Is measured, b is measured when jumping outward, and d =
(A + b) / 2 and (amplitude) = (a−b) / 2 are calculated to determine the offset value and the gain as described above. In addition,
By shortening the track jump time T to 100 to 300 ms, the focus servo band is 1 to 3 kHz.
Since it is higher than z, it does not respond and it is possible to eliminate the deterioration of the amplitude of the track error signal due to defocus. In this embodiment, the analog-digital converter 3
And DSP4, but it is also possible to use an OP amplifier and a peak hold circuit.

[0012]

According to the present invention, the amplitude value of the track error signal is measured during the seek operation to determine the tracking servo gain and the offset value, so that the variations of the track error signal at the disk position due to various factors are eliminated. There is an effect that can be. In addition, a stable tracking error signal can be obtained by performing the above measurement in the final section of the seek operation. Also, during seek operation,
Since the focus error signal when the spot crosses the track is sampled at the zero cross point of the track error signal, accurate focus control is performed and a track error signal without deterioration can be obtained. Further, when the track jump is performed, the amplitude value of the track error signal is measured and the tracking servo gain and the offset value are determined. Therefore, it is possible to remove the variation of the track error signal at the disk position due to various factors.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an optical disk device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a track error signal when the optical pickup device moves in a radial direction of a disc to perform a seek operation.

FIG. 3 is an explanatory diagram showing a track error signal and a focus error signal during a seek operation.

FIG. 4 is an explanatory diagram showing a track error signal during a track jump.

[Explanation of symbols]

 1 ... Optical pickup device 2 ... Amplifier 3 ... A / D converter 4 ... DSP 5 ... Amplifier 6 ... Objective lens actuator

Claims (4)

[Claims] 1. A tracking error signal is generated by detecting a position of a light spot with respect to a track of an optical disc,
In an optical disc device that performs tracking control by moving the lens position of an optical head in the radial direction by the track error signal, the amplitude value of the track error signal is measured during a seek operation, and the optimum value is determined based on the measured amplitude value. An optical disk device comprising a setting means for setting a tracking gain and an offset value. 2. The optical disk apparatus according to claim 1, wherein the setting means sets an optimum tracking gain and offset value based on the amplitude value in the final seek operation section. 3. A focus control means for performing focusing control by sampling a focus error signal when a spot crosses a track during a seek operation at a zero cross point of the track error signal. 2. The optical disk device described in 2. 4. A tracking error signal is generated by detecting a position of a light spot with respect to a track of an optical disc,
In the optical disc device that performs tracking servo correction that moves the lens position of the optical head in the radial direction by this track error signal to perform tracking control, the amplitude value of the track error signal is measured during the track jump operation, and the measured amplitude value is measured. An optical disk device comprising a setting means for setting an optimum tracking gain and offset value based on the above.