JP2720098B2 - Optical head control apparatus and method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an optical head for recording / reproducing on / from an optical disk, in particular, holding a lens system, and controlling the position of the lens system to a neutral position and other lens positions. The present invention relates to an actuator for performing control, for example, tracking control, and an optical head control device including a positioner that holds the actuator and moves an actuator including a lens system in a radial direction of an optical disk.

2. Prior Art An example of this type of control device is shown in FIG. In this figure, a lens / actuator 1 holds a lens system, and performs position control (first control) for holding the lens system at a neutral position.
) And the tracking control (second control) for causing the lens system to follow the track groove, and the actuator coil 9 is provided. The positioner 2 holds the actuator 1 including the lens system by a spring 8, and moves the actuator 1 including the lens system in the radial direction of the optical disk. The sensor 4 detects the amount of displacement 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 10, a phase compensation filter 11, and an output amplifier 13. Position control circuit: input amplifier 5, phase compensation filter
6, including the adder circuit 14 and the output amplifier 7. The outputs of these control circuits are switched by the switching circuit 15, and the control value output from one of the control circuits is given to the actuator coil 9.

In the tracking control, a track error signal TE output from a track error sensor (not shown) of the optical system is given to an input amplifier 10, and a phase compensation circuit 11,
The control signal is supplied to the coil 9 via the output amplifier 13 and the switching circuit 15, and the lens system is controlled so as to follow the track groove of the optical disk.

The position control is performed, for example, when the actuator 1 is moved in the radial direction of the optical disk by the positioner 2, in order to hold the actuator 1 including the lens system at its neutral position. In this position control, the lens error signal LE output from the sensor 4 passes through an input amplifier 5 and a phase compensation filter 6 and is added to a constant value α in accordance with an offset amount of an externally applied lens actuator 1 in an addition circuit 14. Is added. The added output of the adding circuit 14 is supplied 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. When the position control is stopped (for example, the switching circuit 15 selects the tracking control circuit) when the spring 8 is deformed (for example, due to a collision) when an external force is applied to the positioner 2 (for example, due to a collision), the actuator moves to FIG. The position deviates from the neutral position as shown by the broken line. Therefore, the addition value α must be adjusted again.

An object of the present invention is to provide an apparatus and a method capable of automatically adjusting an offset of an actuator even if a change occurs in an offset amount due to a factor in an operation mechanism of the actuator without requiring any external adjustment of the offset.

Means for Solving the Problems An optical head control device according to the present invention includes an actuator and an actuator for holding a lens system and performing a first position control to a neutral position and a second position control for the lens. A positioner that holds and moves an actuator including a lens system in the radial direction of the optical disc;
A sensor that detects the amount of displacement of the actuator with respect to the positioner and outputs a first lens error signal, and drives the actuator based on the first lens error signal output from the sensor so that the lens system is in the neutral position. A first position control circuit, a second position control circuit for driving an actuator to move the lens system in a predetermined direction based on the second lens error signal, and a first position control circuit included in the first position control circuit. During the execution of the control, the first control value generated by the first position control circuit is passed as it is, and when the first position control is switched to the second position control, the first control value is held and output. And a adding circuit for adding the second control value generated by the second position control circuit and the first control value held by the holding circuit in the second position control. For example, the actuator is characterized in that it is driven on the basis of a signal output from the addition circuit in the second position control.

An optical head control method according to the present invention retains a lens system, holds an actuator for performing a first position control to a neutral position and a second position control for a lens, holds the actuator, and includes the lens system. A positioner that moves the actuator in the radial direction of the optical disk,
A sensor that detects the amount of displacement of the actuator with respect to the positioner and outputs a first lens error signal, and drives the actuator based on the first lens error signal output from the sensor so that the lens system is in the neutral position. A first position control circuit, a second position control circuit for driving an actuator to move the lens system in a predetermined direction based on the second lens error signal, and a first position control circuit included in the first position control circuit. A holding circuit for holding the first control value generated by the control circuit, and an adding circuit for adding the second control value generated by the second position control circuit to the first control value held by the holding circuit. In the optical head control device provided with 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 during the first position control. When switching from the first position control to the 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, the first control value is output from the addition circuit. The added value of the two control values is given to the actuator.

In the first position control for holding the lens / actuator at the neutral position, the first control value output from the first position circuit or the average value within a certain period of time is calculated from the first position control by the second position control. In the second position control, the held first control value is added to the original second control value, and the second control value is stored in the second position control. Is performed. Therefore, the offset due to the mechanism of the actuator is removed without the need to externally provide an offset amount for holding the lens system at the neutral position.

Embodiment FIG. 1 conceptually illustrates an optical head control device according to an embodiment of the present invention. In this figure, the same parts as those shown in FIG.

The position control circuit (first position control circuit) includes a sensor 4, an input amplifier 5, a phase compensation filter 6, a holding circuit 7, and an output amplifier 13. Tracking control circuit (second
The position control circuit) has an input amplifier 10, a phase compensation filter 11,
It comprises a control switch 3, an adder circuit 12, and an output amplifier 13. The control switch 3 is turned on / 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. The holding circuit 7 does not perform the operation of holding the control value. The relative displacement between the lens actuator 1 and the positioner 2 is detected by the sensor 4, and a lens error signal (first lens
The error signal (LE) passes through the input amplifier 5 and the phase compensation filter 6, passes through the holding circuit 7, and is output as a position control value to the actuator coil 9 through the addition circuit 12 and the output amplifier 13. In this position control, the holding circuit 7 only passes the position control value but does not hold it.

From the position control to the tracking control (second
Is turned on, the control switch 3 is turned on. The holding circuit 7 holds the last position control value (first control value) in the first position control or the average value (first control value) of the previous position control values and outputs it to the addition circuit 12. . A track error signal (second lens error signal) TE indicating a displacement of the laser spot projected from the lens system with respect to the track groove is output from a track error sensor (not shown), and an input amplifier 10 and a phase It passes through the compensation filter 11 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 adding circuit 12,
This addition result is output to the actuator
Output to the coil 9.

In the above embodiment, the position control (tracking control) with respect to the track groove is used as the target control method for offset removal.
However, it goes without saying that the present invention can be applied to any control method as long as the control is performed in the tracking direction of the lens / actuator.

Effects of the Invention As described above, according to the present invention, in the first position control for holding the lens actuator at its neutral position, the position control value output from the first position control circuit or its average value within a certain period of time is calculated. , When the control shifts from the first position control to the second position control, for example, the tracking control, the holding circuit holds the first control value and the original second control value in the second position control. The second position control is performed based on the result of the addition. Therefore,
There is no need to externally provide an offset amount for holding the lens system at its neutral position, and the offset caused by the actuator mechanism is removed. Therefore,
Unnecessary displacement and vibration of the lens / actuator when switching from the neutral position control to the lens / actuator control or other control can be eliminated.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a configuration of a control device for an optical head according to the present invention. FIG. 2 is a configuration and a block diagram conceptually depicting a conventional optical head control device. DESCRIPTION OF SYMBOLS 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 coil, 12 ... addition circuit, 13 ... output amplifier.

Claims (2)

(57) [Claims] 1. A lens system for holding a first lens system in a neutral position.
An actuator for controlling the position of the optical disk and a second position control for the lens, a positioner for holding the actuator and moving the actuator including the lens system in the radial direction of the optical disk, and detecting the amount of displacement of the actuator with respect to the positioner. A first position control circuit that drives an actuator based on a first lens error signal output from the sensor so that the lens system comes to a neutral position; and a second lens. A second position control circuit for driving the actuator to move the lens system in a predetermined direction based on the error signal, which is included in the first position control circuit and is generated by the first position control circuit during execution of the first position control When the first control value is passed as it is and is switched from the first position control to the second position control, And a holding circuit for holding and outputting the first control value, and a second control value generated by the second position control circuit in the second position control and the first control value held by the holding circuit. An optical head control device, comprising: an adder circuit for adding an actuator; and driving an actuator based on a signal output from the adder circuit in the second position control. 2. A lens system, comprising:
A positioner that holds an actuator and an actuator for performing the position control of the lens and the second position control of the lens, moves the actuator including the lens system in the radial direction of the optical disk, and detects the amount of displacement of the actuator with respect to the positioner. A first position control circuit for driving an actuator based on a first lens error signal output from the sensor so as to bring the lens system to a neutral position;
A second position control circuit for driving an actuator to move the lens system in a predetermined direction based on the lens error signal of the first position control circuit and a first control generated by the first position control circuit A control circuit for an optical head, comprising: a holding circuit for holding the value; and an adding circuit for adding the second control value generated by the second position control circuit and the first control value held by the holding circuit. During the execution of the first position control, the first control value generated by the first position control circuit is passed through the holding circuit and given to the actuator, so that the first position control is switched from the first position control to the 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, an added value of both control values output from the addition circuit is supplied to the actuator. control Method.