JPH0461035A - Controller and method for optical head - Google Patents

Abstract

PURPOSE:To eliminate offset due to the mechanism of an actuator without applying offset amount to hold a lens system in a closed center by providing a holding circuit holding and outputting a first control value when exchanged from first position control to second position control. CONSTITUTION:In the first position control holding a lens actuator 1 in the closed center, the first control value outputted from first position control circuits 4/5/6/7/13 or the average value within constant time are held in a holding circuit 7 when shifting from the first position control to the second position control, for example, when shifted to tracking control, this held first control value is added with the original second control value in the second position control, and the second position control is performed by this addition result. Thus, the elimination of the offset due to the mechanism of the actuator without applying the offset amount to hold the lens system in the closed center from the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a control device for a Tameno optical head that performs recording/reproduction on an optical disk, and in particular to a control device for holding a lens system and controlling the position of the lens to a neutral position and controlling the position of other lenses. For example, the present invention relates to an optical head control device that includes an actuator for tracking control, and a positioner that holds the actuator and moves the actuator including a lens system in the radial direction of an optical disk.

Prior Art An example of a control device of this type is shown in FIG. In this figure, the lens actuator 1 holds the lens system and performs position control (first control) to hold the lens system in a neutral position and tracking control (second control) to make the lens system follow the track groove. It is also used as an actuator.
It is equipped with a coil 9. The positioner 2 holds the actuator 1 including the lens system with a spring 8, and moves the actuator 1 including the lens system in the radial direction of the optical disc. The sensor 4 detects the amount of positional deviation of the lens system (actuator 1) with respect to the positioner 2, and outputs a lens error signal LE.

This control device includes a tracking control circuit and a position control circuit. The tracking control circuit includes an input amplifier IO2 phase compensation filter 11 and an output amplifier 13. The position control circuit includes an input amplifier 51, a phase compensation filter 6, an adder circuit 14, and an output amplifier 7. The outputs of these control circuits are switched by a switching circuit I5, and the control value output from either one of the control circuits is applied to the actuator coil 9.

In tracking control, a track error signal TE output from a track error sensor (shown in the figure) of an optical system is applied to an input amplifier 10 and a phase compensation circuit 1
1. Coil 9 via output amplifier 13 and switching circuit 15
The lens system is controlled to follow the track groove of the optical disc.

Position control is performed to maintain the actuator 1 including the lens system at its neutral position, for example, when the actuator 1 is moved in the radial direction of the optical disk by the positioner 2. In this position control, the lens error signal LE output from the sensor 4 passes through an input amplifier 51 and a phase compensation filter 6, and then in an adder circuit 14, a constant value α corresponding to the offset amount of the lens actuator 1 given from the outside is determined. will be added. The added output of the adder circuit 14 is applied to the coil 9 via the output amplifier 7 and the switching circuit 15.

Problems to be Solved by the Invention In the conventional control device as described above, after the addition value α is once adjusted while the actuator 1 is held at the neutral position as shown by the solid line in FIG. For example, when an external force is applied to the positioner 2 and the spring 8 is deformed (for example, due to a collision), when the 1-position control is stopped (the switching circuit 15 selects the tracking control circuit), the actuator is activated as shown in the broken line in FIG. As shown in the figure, it deviates from the neutral position. Therefore, the additional value α must be adjusted again.

The second invention provides an apparatus and method that does not require any external adjustment of the offset of the actuator and can automatically adjust even if the amount of offset changes due to factors related to the operating mechanism of the actuator.

Means for Solving the Problems An optical head control device according to the present invention includes an actuator for holding a lens system and performing first position control to the neutral position of the lens system and second position control regarding the lens. a positioner that holds the actuator and moves the actuator including the lens system in the radial direction of the optical disk; a sensor that detects the amount of positional deviation of the actuator with respect to the positioner and outputs a first lens error signal; and a first lens error output from the sensor. a first position control circuit that drives the actuator to bring the lens system to a neutral position based on the signal; a second position control circuit that drives the actuator to move the lens system in a predetermined direction based on the second lens error signal; The control circuit is included in the first position control circuit, and during execution of the first position control, the first control value generated in the first position control circuit is passed through as is, and the first control value is changed from the first position control to the second position. A holding circuit that holds and outputs the first control value when switching to control, and a second control value generated by the second position control circuit in the second position control and the first control value held in the holding circuit. The actuator is characterized in that it includes an addition circuit that adds the control value and the actuator is driven based on a signal output from the addition circuit in the second position control.

A method for controlling an optical head according to the present invention includes: an actuator for holding a lens system and performing a first position control of the lens to its neutral position and a second position control regarding the lens; A positioner that moves the actuator in the radial direction of the optical disk, a sensor that detects the amount of positional deviation of the actuator with respect to the positioner and outputs a first lens error signal, and a lens system based on the first lens error signal output from the sensor. a first position control circuit that drives the actuator to bring the lens system to a neutral position; a second three-position control circuit that drives the actuator to move the lens system in a predetermined direction based on a second lens error signal; A holding circuit that is included in the position control circuit and holds the first control value generated by the first position control circuit, and a second control value generated by the second position control circuit and held in the holding circuit. In an optical head control device including an addition circuit for adding a first control value and a first control value, the first control value generated by the first position control circuit is passed through the holding circuit during execution of the first position control. is applied to the actuator to cause the holding circuit to hold the first control value generated by the first position control circuit when switching from the first position control to the second position control, and in the second position control, The present invention is characterized in that an added value of both control values outputted from the adding circuit is given to the actuator.

The first actuator holds the working lens actuator in its neutral position.
A holding circuit holds the first control value output from the first position control circuit in the position control or its average value within a certain period of time when the first position control is transferred from the first position control to the second position control, for example, tracking control. In the second position control, the held first control value is added to the original second control value, and the second position control is performed based on the addition result. Therefore, the offset caused by the actuator mechanism is removed without the need to externally provide an offset amount to maintain the lens system in its neutral position.

Embodiment FIG. 1 conceptually depicts an optical head control device according to an embodiment of the present invention. In this figure, the same components as those shown in FIG. 2 are denoted by the same reference numerals, and their explanation will be omitted.

The position control circuit (first position control circuit) includes a sensor 4, an input amplifier 52, a phase compensation filter, a holding circuit 7, and an output amplifier 13. The tracking control circuit (second position control circuit) includes an input amplifier 10. Phase compensation filter 11. It is composed of a control switch 3° adder circuit 12 and an output amplifier 13.

The control switch 3 is controlled on and off by a switching signal. The holding operation of the holding circuit 7 is also controlled by the switching signal.

In the first position control, the control switch 3 is turned off. Further, the holding circuit 7 does not hold the control value.

The amount of relative positional deviation between the lens actuator 1 and the positioner 2 is detected by the sensor 4, and the lens error signal (first lens error signal) LE output from the sensor 4 is sent to the input amplifier 5. It passes through the phase compensation filter 6 and the holding circuit 7, and is output as a position control value to the actuator coil 9 through the adder circuit 12 and the output amplifier 13. In this position control, the holding circuit 7 only passes the position control value;
It will not be retained.

When the switching signal switches from position control to tracking control (second position control), the control switch 3 is turned on. Further, the holding circuit 7 holds the last position control value (first control value) in the first position control.

Alternatively, the average value (first control value) of the position control values up to that point is held and output to the addition circuit 12. A track error signal (second lens error signal) TE representing the positional deviation of the laser spot projected from the lens system with respect to the track groove is output from the track error sensor (path shown), and input to the input amplifier 10 and the phase Compensation filter 1
1 and becomes the track direction control value of the lens actuator 1. This control value (second control value) passes through the switch 3 and is added to the control value (first control value) held in the holding circuit 7 in the adder circuit 12, and the result of this addition is passed through the output amplifier 13 to the actuator coil. 9.

In the above embodiment, the target control method for offset removal is as follows:
Although the position control (tracking control) with respect to the track groove has been described, it goes without saying that the present invention can be applied to any control method as long as it controls the lens actuator in the tracking direction.

Effects of the Invention As described above, according to the present invention, in the first position control for holding the lens actuator in its neutral position, the device control value constituted by the first position control circuit or its average value within a certain period of time is controlled. , from the first position control to the second position control For example, when transitioning to tracking control, it is held in a holding circuit, and in the second position control, this held first control value is added to the original second control value. However, the second position control is performed based on this addition result. Therefore, the offset caused by the actuator mechanism is removed without the need to externally apply an offset amount to maintain the lens system in its neutral position. Therefore, it is possible to eliminate unnecessary displacement, vibration, etc. of the lens actuator when switching from neutral position control to lens actuator control or other control.

[Brief explanation of the drawing]

FIG. 1 is a conceptual configuration and block diagram of the configuration of an optical head control device according to the present invention. FIG. 2 is a conceptual configuration and block diagram of a conventional optical head control device. 1... Lens actuator. 2...Positioner 3...Control switch 4...Sensor. 5.10... Input amplifier 6.11... Phase compensation filter. 7...Holding circuit. 8...Spring. 9...Actuator φ coil. I2...addition circuit. 13... Output amplifier. that's all

Claims (2)

[Claims] (1) An actuator that holds the lens system and performs first position control to its neutral position and second position control regarding the lens; A positioner for moving, a sensor for detecting the amount of positional deviation of the actuator with respect to the positioner and outputting a first lens error signal, and a sensor for moving the lens system to a neutral position based on the first lens error signal output from the sensor. a first position control circuit that drives the actuator; a second position control circuit that drives the actuator to move the lens system in a predetermined direction based on a second lens error signal; While the first position control is being executed, the first control value generated by the first position control circuit is passed through as is, and the first control value is held when switching from the first position control to the second position control. and an adder circuit that adds the second control value generated by the second position control circuit and the first control value held in the holding circuit in the second position control; 2. An optical head control device in which an actuator is driven based on a signal output from an adder circuit in position control. (2) An actuator for holding the lens system and performing first position control to its neutral position and second position control regarding the lens, holding the actuator and moving the actuator including the lens system in the radial direction of the optical disk. A positioner to be moved, a sensor that detects the amount of positional deviation of the actuator with respect to the positioner and outputs a first lens error signal, and a lens system that moves the lens system to a neutral position based on the first lens error signal output from the sensor. a first position control circuit that drives the actuator; a second position control circuit that drives the actuator to move the lens system in a predetermined direction based on the second lens error signal; A holding circuit that holds the first control value generated by the first position control circuit, and a second control value generated by the second position control circuit and the first control value held in the holding circuit. In the optical head control device including an adding circuit that performs the first position control, during execution of the first position control, the first control value generated by the first position control circuit is passed through the holding circuit and applied to the actuator; When switching from position control to second position control, the first control value generated by the first position control circuit is held in the holding circuit, and in the second position control, both values output from the addition circuit are A method of controlling an optical head in which an added value of control values is applied to the actuator.