JPH06325393A - Device for setting gain value of servo control system for optical pickup actuator - Google Patents

Abstract

PURPOSE:To make the servo performance of several device uniform by severally setting the gain value of a servo control system at every reproducing device when the dispersion in the sensitivity of the actuator of an optical pickup exists at every reproducing device. CONSTITUTION:Switches S1-S4 are connected to the input port of a CPU 17. Then, according to the switching states of the switches S1-S4, the gain setting value of an actuator coil 15 in the direction of focusing among the gain setting values outputted from the CPU 17 to a gain setting/phase compensation circuit 9 is made revisable. Further, according to the switching states of the switches S3, S4, the gain setting value of the actuator coil 15 in the direction of tracking is made revisable. Then, by optionally setting the switching states of the switches S1-S4, the dispersion in the sensitivity of the actuator is absorbed by setting the gain of the servo control system. Thus, the dispersion in the gain of the servo control system due to the dispersion in the sensitivity of the actuator is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided in an optical disk reproducing apparatus, and sets a gain value for focus servo control or tracking servo control of an actuator of an optical pickup for a servo control system. It relates to the device.

[0002]

2. Description of the Related Art CDs and CD-Is (CD-interacs)
A playback device for playing back information from an optical disk such as a Tive) or a CD-ROM is provided with an optical pickup arranged so as to face the disk surface, and the information is played from the optical pickup toward a track on the disk surface. The information recorded on the optical disk is reproduced based on the reflected light. Further, in such a reproducing apparatus, in order to move the optical pickup to follow the track in accordance with surface wobbling or eccentric rotation of the optical disc, the shift of the focus position or tracking position of the optical pickup with respect to the disc surface is detected and detected. In accordance with the result, the voltage applied to the focusing or tracking actuator coil provided in the actuator for moving the optical pickup in the focusing direction or the tracking direction is servo-controlled.

FIG. 4 is a block diagram showing a schematic structure of a conventional servo control system for digitally servo-controlling the voltage applied to the actuator coil 15. As shown in this figure, conventionally, from the optical pickup 1 to the optical disc 3,
A focus error signal FE is obtained from the reflected light by irradiating light for focus error detection or light for tracking error detection, and a tracking error signal TE is obtained by the push-pull method or the three-beam method. There is. The focus error signal FE and the tracking error signal TE are supplied to the servo processor 11 including the A / D converter 5, the level adjustment circuit 7, and the gain setting / phase compensation circuit 9.

In the servo processor 11, the focus error signal FE and the tracking error signal TE are first converted into digital signals by the A / D converter 5, and then the level adjusting circuit 7 compensates for variations in the reflectance of the optical disk 3. Is adjusted to the desired level to
The gain setting / phase compensation circuit 9 sets the gain of the servo control system and also compensates the phase. Then, the focus error signal FE and the tracking error signal TE for which gain setting and phase compensation have been performed are applied as a voltage to the actuator coil 15 for focusing and tracking through the actuator driver 13,
The actuator coil 15 moves the position of the optical pickup 1 in the focus direction and the tracking direction.

[0005]

By the way, the gain value of the servo control system set by the gain setting / phase compensation circuit 9 is determined by the CPU 17 provided for the overall control of the reproducing apparatus. The gain value set by is a fixed and single value. Therefore, if there is a variation in the sensitivity of the actuator coil 15 with respect to the voltage applied from the servo processor 11, the variation remains as a variation in the gain of the servo control system, and a variation occurs in the servo performance of each device. There is a problem that the playability of the servo is lowered due to the change of the intersection, and the quality of each device is not stable.

The present invention has been made in view of the above problems, and can reduce variations in gain of a servo control system due to variations in actuator sensitivity of an optical pickup, and particularly for an optical pickup actuator performing digital servo control. An object of the present invention is to provide a gain value setting device for a servo control system.

[0007]

In order to solve the above problems, the present invention provides an optical pickup for reproducing information recorded on an optical disc, and an actuator for moving the optical pickup in a focus direction and a tracking direction.
A servo control system for an optical pickup actuator, which is provided with a servo processor for digitally servo-controlling the drive of the actuator so as to eliminate the deviation of the focus direction and the tracking direction of the optical pickup with respect to the optical disc, and the servo control by the servo processor A gain value setting device for setting the gain value of the gain value and outputting the gain value to the servo processor, wherein the gain value input means is operated according to the gain value, and a signal indicating the gain value according to the operation of the gain value input means. And a gain value signal generating / outputting means for generating and outputting to the servo processor.

[0008]

According to the gain value setting device of the servo control system for an optical pickup actuator of the present invention, when the gain value input means is operated in accordance with a desired gain value to be set to the servo processor, the operation is performed in response to the operation. A signal indicating the gain value is generated by the gain value signal generation / output means, the generated signal is output to the servo processor, and the actuator for moving the optical pickup in the focus direction and the tracking direction is driven by the gain value signal generation / output means. Focus and tracking servo control is performed according to the gain value output from the servo processor.

Therefore, for example, when there is a variation in the sensitivity of the actuator of the optical pickup for each reproducing device, the actuator sensitivity of each reproducing device is measured in advance, and the reproducing device is adjusted for each reproducing device according to the measurement result. By setting different gain values by operating the gain value input means, it is possible to set a gain value of the servo control system suitable for absorbing the variation in the actuator sensitivity between the reproducing devices for each reproducing device. The servo performance of each device can be made uniform to stabilize the quality of the device.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are views showing an embodiment of a gain value setting device of a servo control system for an optical pickup actuator according to the present invention. FIG. 1 is a partial block diagram showing a digital servo control system for an optical pickup actuator including a gain setting device according to an embodiment of the present invention. In FIG. 1, the same parts as those shown in FIG. 4 will be described with the same reference numerals as those shown in FIG.

In the servo control system of this embodiment shown in FIG. 1,
Two contact type switches S ₁ , S ₂ , S ₃ , S ₄ (corresponding to gain value input means) such as a DIP switch are connected to the four input ports of the CPU 17. Then, the gain set value in the focus direction of the actuator coil 15 can be changed among the set values of the gain output from the CPU 17 to the gain setting / transfer compensation circuit 9 according to the switching state of the switches S ₁ and S _2. , The gain setting value of the actuator coil 15 in the tracking direction can be changed according to the switching states of the switches S ₃ and S ₄ .

FIG. 2 shows the correspondence between the switching states of the switches S ₁ and S ₂ and the gain setting value in the focus direction output from the CPU 17, and the switching states of the switches S ₃ and S _{4 and} the output from the CPU 17. It is a figure which shows the correspondence with the gain setting value of a tracking direction. In addition, "L" in FIG. 2 indicates a switch ON, and "H" indicates a switch OF.
F is shown. In the present embodiment, assuming that the range of variation in the sensitivity of the actuator coil 15 is ± 7 dB in the focusing direction and the tracking direction, respectively, the switching states of the switches S ₁ and S ₂ and the switches S ₃ and S ₄ are changed. The gain setting value output from the CPU 17 according to
"0 dB", "-4.5 dB", "+4.
CPU so that it can be changed to three of "5 dB"
Make up 17. That is, in this embodiment, the CPU 17
Corresponds to the gain value signal generation / output means.

Therefore, for example, the actuator coil 1
When the sensitivity in the focus direction (tracking direction) of 5, that is, the initial value is +3 dB or more, the switch S ₁ (switch S ₃ ) is turned on and the switch S ₂ (switch S ₄ ) is turned on.
Set to FF, and gain of servo control system is "-4.5dB".
Set to. On the contrary, when the initial value is -3 dB or less, the switch S ₁ (switch S ₃ ) is turned off and the switch S is turned off.
₂ (Switch S ₄ ) is turned on and the gain is set to “+ 4.5d
Set to "B". When the initial value is within ± 3 dB, the switch S ₁ (switch S ₃ ) and the switch S _3
2 (switch S ₄ ) is turned off and gain is set to “+
0 dB ”.

FIG. 3 shows the switches S ₁ and S ₁ as described above.
₂ is a diagram showing a correlation between variations in sensitivity of the actuator coil 15 before and after gain adjustment when the switching state of ₂ (switches S ₃ and S ₄ ) is changed. This Figure 3
As shown in (1), it is understood that the range of the variation in the sensitivity of the actuator coil 15 which was ± 7 dB before the gain adjustment (initial value) is suppressed to ± 2.5 dB after the gain adjustment.

As described above, in the servo control system of the present embodiment, the CPU 17 which outputs the gain setting value to the gain setting / phase compensation circuit 9 of the servo processor 11 has four switches S ₁ and S for changing the setting value. ₂ , S ₃ , S ₄ are connected, the gain setting value in the focus direction of the actuator coil 15 can be changed according to the switching state of the switches S ₁ , S ₂ , and the switching state of the switches S ₃ , S ₄ can be changed. Depending on,
The CPU 17 is configured so that the gain setting value of the actuator coil 15 in the tracking direction can be changed.

Therefore, for example, when assembling and manufacturing the disc reproducing apparatus, the variations in the sensitivity of the actuator coil 15 in the focus direction and the tracking direction are measured, and the switches S ₁ , S ₂ and the switch S are adjusted according to the measured values. By arbitrarily setting the switching state of ₃ and S ₄ , the variation in the sensitivity of the actuator coil 15 can be absorbed by the gain setting of the servo control system. Therefore,
It is possible to reduce the variation in the gain of the servo control system due to the variation in the sensitivity of the actuator coil 15, eliminate the variation in the servo performance of each device, and the reduction in the playability of the servo due to the variation in the gain intersection point.
It is possible to stabilize the servo control system, improve the playability of the servo, and stabilize the quality of the device.

In this embodiment, the patterns of gain setting values obtained according to the switching states of the switches S ₁ and S ₂ and the switches S ₃ and S ₄ are “0 dB”, “−4.5 dB”,
Although the case of “+4.5 dB” has been described, this numerical value can be appropriately changed depending on the range of variations in the sensitivity of the actuator coil 15. Further, in the present embodiment, the case where the four switches S ₁ , S ₂ , S ₃ and S ₄ are connected to the CPU 17 has been described, but the number of switches may be further increased. Then, if the number of switches is increased, the interval of the gain setting values obtained becomes narrower, and the variation in the sensitivity of the actuator coil 15 can be suppressed within a narrower range, and ultimately the variation can be suppressed to the limit.

[0018]

As described above, according to the present invention, by operating the gain value input means according to a desired gain value to be set for the servo processor, a signal indicating the gain value according to the operation. Is generated by the gain value signal generation output means, the generated signal is output to the servo processor, and the drive of the actuator for moving the optical pickup in the focus direction and the tracking direction is output from the gain value signal generation output means to the servo processor. Since the focus and tracking servo control is performed according to the gain value, for example, when there is a variation in the sensitivity of the actuator of the optical pickup for each reproducing device, the actuator between the reproducing devices according to the actuator sensitivity of each reproducing device. Gain value of servo control system suitable for absorbing sensitivity variations , Can be set individually for each player, the quality of the device to equalize the servo performance of individual devices can be stabilized.

[Brief description of drawings]

FIG. 1 is a partial block diagram showing a digital servo control system for an optical pickup actuator including a gain setting device according to an embodiment of the present invention.

2 is a switching state of a switch shown in FIG. 1 and a CPU
It is a figure which shows the correspondence with the gain setting value of the focus direction and tracking direction output from.

FIG. 3 is a diagram showing a correlation between variations in sensitivity of actuator coils before and after gain adjustment (initial value) and after adjustment when the switching state of the switch shown in FIG. 1 is changed.

FIG. 4 is a block diagram showing a conventional digital servo control system for an optical pickup actuator.

[Explanation of symbols]

1 Optical Pickup 3 Optical Disc 5 A / D Converter 7 Level Adjustment Circuit 9 Gain Setting / Phase Compensation Circuit 11 Servo Processor 13 Actuator Driver 15 Actuator Coil 17 CPU (Gain Value Signal Generation / Output Means) FE Focus Error Signal TE Tracking Error Signal S ₁ , S ₂ , S ₃ , S ₄ switches (gain value input means)

Claims (1)

[Claims] 1. An optical pickup for reproducing information recorded on an optical disc, an actuator for moving the optical pickup in a focus direction and a tracking direction, and a shift of the optical pickup in the focus direction and the tracking direction with respect to the optical disc. In a gain value setting device which is provided in a servo control system for an optical pickup actuator, which comprises a servo processor for digitally servo-controlling the drive of the actuator, and which sets a gain value for servo control by the servo processor and outputs the gain value to the servo processor. There is a gain value input unit that is operated according to the gain value, and a gain value signal generation and output unit that generates a signal indicating a gain value according to the operation of the gain value input unit and outputs the signal to the servo processor. Equipped with And a gain value setting device for a servo control system for an optical pickup actuator.