JPH10247323A - Method for controlling access to optical disk, and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform stable access to a track at the time of sudden acceleration and deceleration of a pickup. SOLUTION: When the pickup traverses a target track from an initial position of an optical disk, a speed profile (PLF signal) is outputted by a microcomputer 2. Then, the difference value between a present speed of the pickup detected from a present speed detecting part 1 and the PLF signal is calculated by a differential amplifier 3 to output a speed control signal showing a speed error. This speed control signal is given via a resistor 12 to an actuator driver 4, and is also given via a resistor 13 and a high band compensation circuit 16 to a motor driver 5. Thus, the responsiveness of a pickup moving motor 7 is enhanced, and hence a burden on a tracking coil 6 is lightened, accordingly. Consequently, an inclination of an optical axis of a lens to be made at the time of sudden acceleration is diminished, and the stable access to a track can be carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical disk access control method for controlling the position of an optical disk drive pickup and an optical disk access control device.

[0002]

2. Description of the Related Art Conventionally, in an optical disk drive, various methods have been adopted as a track jump moving method for moving a pickup. In recent years, higher speed and more accurate optical disk drives have been required more and more. Among them, in a track counting method in which a track is jumped accurately while counting tracks on a disk, a speed of a pickup moving motor (also referred to as a traverse motor) is determined based on a track cross signal optically obtained from the pickup. Feedback control is being performed.

In this control method, a microcomputer sets a speed profile (PLF) in an acceleration section, a constant speed section, and a deceleration section, or a speed profile in an acceleration section and a deceleration section, based on the number of tracks to a destination, and crosses tracks. While counting the number of (track cross), the actual track cross speed obtained from the pickup,
A difference value with the speed profile is calculated. The difference value is applied as a speed control signal to the pickup moving motor to perform speed control according to the speed profile.

In this case, control using only the pickup moving motor cannot capture each track located at an interval of 1.6 μm (strictly speaking, 1.6 ± 0.1 μm in the Red Book standard). For this reason, control is performed to add a fixed amount of the difference value between the track cross speed and the speed profile to a lens actuator that performs tracking servo and focusing servo of a focusing lens (hereinafter, referred to as a lens). This control method will be described with reference to FIG.

FIG. 2 is a conceptual diagram showing a general configuration of a conventional optical disk access control device. The optical disk access control device includes a current speed detection unit 1 for detecting a current speed by counting the number of tracks traversed by a light beam in a unit time;
A microcomputer 2, which outputs a speed profile,
A differential amplifier 3 that calculates a difference value between the speed profile and the current speed, an actuator driver 4 that amplifies the output of the differential amplifier 3 to generate a drive signal, a motor driver 5, a tracking coil (lens) that performs tracking servo of the lens And a pickup moving motor 7 for moving the pickup in the transverse direction of the truck.

The current speed signal detected by the current speed detecting section 1 is supplied to a negative input terminal of the differential amplifier 3 via a resistor 8, and the PLF signal of the microcomputer 2 is supplied via a resistor 9 to the differential amplifier 3. + Input terminal. The differential amplifier 3 subtracts the current speed signal from the PLF signal, and outputs a feedback resistor 10, a ground resistor 11 at the + input terminal, a resistor 8 at the input terminal,
9 is a circuit for calculating and amplifying the difference value with the amplification factor determined in step (9). The speed control signal output from the differential amplifier 3 is supplied to the actuator driver 4 via the resistor 12 and to the motor driver 5 via the resistor 13.

First, the microcomputer 2 supplies a PLF signal to the + input terminal of the differential amplifier 3 and the current speed detecting unit 1
At the negative input terminal of the differential amplifier 3. At the start of the movement, the value of the current speed signal is 0, the value of the speed profile is output from the differential amplifier 3, and this signal is converted into a drive signal by the actuator driver 4 and the motor driver 5, and the tracking coil 6 and the pickup move. It is applied to each of the motors 7. Thus, the pickup starts moving.

When the pickup starts moving, the light beam emitted from the lens traverses the track of the optical disk, so that the current speed detecting section 1 outputs the speed at the start of the movement.
In this state, the differential amplifier 3 outputs a difference value between the value of the speed profile and the current speed. By such control, when the pickup moves faster than the indicated value of the speed profile, a speed control signal is output so as to reduce the speed of the pickup, and when the pickup moves slower than the indicated value of the speed profile, the speed of the pickup is increased. A speed control signal is output. When a preset time comes, the microcomputer 2 stops the acceleration instruction and outputs a constant speed instruction. Then, when the count value of the number of tracks becomes equal to or more than the set value, deceleration is instructed from there.

[0009]

As described above, the optical pickup is feedback-controlled via both the pickup moving motor 7 and the tracking coil 6. Therefore,
In this way, the speed control signal is given to the actuator driver 4 and the motor driver 5 via a certain value of resistance,
When the pickup moves at high speed or suddenly accelerates and decelerates,
It is strongly affected by load fluctuations on pickup rails. Therefore, if the control is performed by using the speed control signal indicating the speed error as it is, the control is performed so that the tracking coil 6 bears the movement of the pickup that is insufficient.

In this case, the optical axis of the lens in the pickup is too deviated, and the visual field characteristics seen from the lens deteriorate,
Eventually, you will not be able to count the number of times you cross the track.
Also, even at the arrival position, there is a risk that the tracking servo is not applied because the lens is too biased.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and holds the position of the lens at the center of the pickup even when the pickup is moving at a high speed. It is an object to realize an optical disk access control method and an optical disk access control device capable of improving the positioning accuracy of the optical disk.

[0012]

According to a first aspect of the present invention, there is provided a tracking coil for controlling an optical axis of a focusing lens, and the focusing lens is finely movable. An optical disc access control method for controlling the positioning of the optical axis on a target track of an optical disc by using a pickup held in the optical disc, wherein when the number of tracks up to the target track is set, the set crossing of the pickup with respect to each track position is performed. The speed profile storing the speed data is read, the actual traversing speed of the pickup truck is detected, the difference value between the set traversing speed and the actual traversing speed is calculated as a speed control signal, and the speed control signal is tracked. The speed control signal and the high frequency component of the speed control signal are added to the coil It is characterized in that for the driver of up moving motor.

According to a second aspect of the present invention, there is provided a tracking coil for controlling an optical axis of a focusing lens, and the optical axis is set to a target of an optical disk by using a pickup for holding the focusing lens movably. An optical disc access control device for performing positioning control on a track, wherein when a number of tracks up to the target track is set, a speed instruction unit for reading a speed profile storing data of the set transverse speed of the pickup with respect to each track position; A current speed detecting unit for detecting an actual traversing speed of the pickup truck, a difference value between a set traversing speed of the speed indicating unit and an actual traversing speed of the current speed detecting unit, and the difference value is used as a speed control signal. And a speed control signal of the calculating means, and an algorithm for driving the tracking coil. A tutor driver, a high-frequency compensating means for extracting a high-frequency component of the speed control signal, and a pickup movement for moving the pickup by inputting a speed control signal of the calculating means and an output of the high-frequency compensating means together A motor driver for driving a motor is provided.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical disk access control method according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a basic configuration diagram of an optical disk access control device used in the optical disk access control method of the present embodiment. In this figure, the same parts as those of the conventional example are denoted by the same reference numerals, and detailed description is omitted.

The optical disk access control device according to the present embodiment has a current speed detecting section 1, a microcomputer 2, a differential amplifier 3, an actuator driver 4, a motor driver 5, a tracking coil 6, a pickup moving motor 7 as in the conventional example. It is comprised including.

When the number of tracks up to the target track of the optical disk is set, the microcomputer 2 has a function of a speed indicating unit for reading out a speed profile (PLF) storing data of the set transverse speed of the pickup for each track position. Have. Current speed detector 1
Is to detect the actual traversing speed of the pickup truck. The differential amplifier 3 is a calculating unit that calculates a difference value between the set crossing speed of the speed instruction unit and the actual crossing speed of the current speed detection unit, and outputs the difference value as a speed control signal.

The current speed signal of the current speed detector 1 is a resistor 8
, Which is applied to the negative input terminal of the differential amplifier 3 via the
The signal is applied to the + input terminal of the differential amplifier 3 via the resistor 9. The differential amplifier 3 subtracts the current speed signal from the PLF signal, and provides a feedback resistor 10, a ground resistor 11 at the + input terminal,
The subtraction value is amplified at an amplification rate determined by the resistors 8 and 9 at the input end. The speed control signal output from the differential amplifier 3 is given to the actuator driver 4 via the resistor 12.

Unlike the conventional example, the speed control signal output from the differential amplifier 3 is transmitted through the resistor 13 to the motor driver 5.
To the motor driver 5 through a high-frequency compensation circuit 16 comprising a series connection of a resistor 14 and a capacitor 15. The high-frequency compensation circuit 16 converts the high-frequency component of the speed control signal
It is a circuit that gives extra.

The actuator driver 4 power-amplifies the input speed control signal and outputs a drive current to the tracking coil 6. Similarly, the motor driver 25 power-amplifies the speed control signal input through the resistor 13 and the high-frequency compensation circuit 16 and outputs a drive current to the pickup moving motor 7.

The operation of the optical disk access control device thus configured will be described. The current speed signal output from the current speed detection unit 1 is provided to the minus input terminal of the differential amplifier 3, and the PLF signal output from the microcomputer 2 is provided to the plus input terminal. The differential amplifier 3 subtracts the current speed signal from the PLF signal to generate a speed control signal that is a speed error signal. This speed control signal is input to the actuator driver 4 via the resistor 12, where the power is amplified and the tracking coil 6 is driven.

On the other hand, the speed control signal is input to the motor driver 5 via the resistor 13 and the high-frequency compensation circuit 1
At 6, the high frequency component of the speed control signal is extracted, and the component is also input to the motor driver 5. These signals are amplified in power and drive the pickup moving motor 7.

The speed control of the entire pickup is feedback control, and both the tracking coil 6 and the pickup moving motor 7 are included in the control loop. Therefore, if the pickup moving motor 7 does not follow well, a load is applied to the tracking coil 6. Conversely, if the tracking actuator including the tracking coil 6 does not follow well, the pickup moving motor 7 is burdened.

However, since the tracking coil 6 only moves a light lens, it follows up to several kHz. However, since the pickup moving motor 7 moves the heavy pickup itself, it can follow only up to about several tens Hz at most.

Therefore, in the present embodiment, the following frequency of the pickup moving motor 7 is increased by adding a high-frequency component of the speed control signal to the pickup moving motor 7 that does not follow the high frequency sufficiently. In this case, the followability of the pickup moving motor 7 is improved, and the amount of shift of the lens is reduced by the amount of the improved component due to the feedback control. That is, in order to reduce the shift amount of the lens, the signal given to the pickup moving motor 7 should be increased rather than increasing the signal to the tracking coil 6 for directly finely moving the optical axis of the lens. Thus, the function of accessing the optical disk can be achieved.

With the above control, the optical axis of the lens is held perpendicular to the recording surface of the medium even when the pickup is moving at high speed, and stable track access can be realized.

[0026]

As described above, according to the present invention, even when the pickup is moving at a high speed, the position of the lens can be held at the center of the pickup, and the speed of track access can be increased. Further, the tracking servo is stably applied at the arrival position of the pickup. Since the pickup can be moved at high speed in this manner, the seek time of the track on the optical disk can be reduced.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of an optical disk access control device according to an embodiment of the present invention.

FIG. 2 is a basic configuration diagram of a conventional optical disk access control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Current speed detection part 2 Microcomputer 3 Differential amplifier 4 Actuator driver 5 Motor driver 6 Tracking coil 7 Pickup movement motor 8, 9, 10, 11, 12, 13, 14 Resistor 15 Capacitor 16 High frequency compensation circuit

Claims (2)

[Claims] 1. An optical disk access control method comprising a tracking coil for controlling an optical axis of a focusing lens, and positioning control of the optical axis on a target track of the optical disk by using a pickup for holding the focusing lens movably. When the number of tracks up to the target track is set,
A speed profile storing data of the set crossing speed of the pickup for each track position is read, an actual crossing speed of the pickup truck is detected, and a difference value between the set crossing speed and the actual crossing speed is set as a speed control signal. An optical disc access control method, comprising: calculating and providing the speed control signal to a driver of the tracking coil; and providing the speed control signal and a high-frequency component of the speed control signal to a driver of a pickup moving motor. 2. An optical disk access control device having a tracking coil for controlling the optical axis of a focusing lens, and positioning and controlling the optical axis on a target track of the optical disk by using a pickup for holding the focusing lens movably. When the number of tracks up to the target track is set,
A speed indicator for reading a speed profile storing data of the set crossing speed of the pickup for each track position; a current speed detector for detecting an actual crossing speed of the truck of the pickup; and a set crossing speed of the speed indicating unit. And a calculating means for calculating a difference value between the actual traversing speed of the current speed detecting unit and the difference value as a speed control signal; and an actuator driver for inputting a speed control signal of the calculating means and driving the tracking coil. A high-frequency compensating means for extracting a high-frequency component of the speed control signal; a pickup moving motor for inputting a speed control signal of the calculating means and an output of the high-frequency compensating means together to move the pickup; A motor driver to drive,
An optical disk access control device, comprising: