JPH03235226A - Oscillation brake circuit for optical pickup lens - Google Patents

Abstract

PURPOSE:To converge oscillation at the time of tracking an optical pickup and to shorten stop time to a target position by an oscillation brake circuit combining existent parts such as a phase compensating circuit, reversal arithmetic circuit and a filter, etc. CONSTITUTION:For an LRF signal A removing a direct current component from a reproducing signal 2 to detect the laser spot position of a pickup lens, a low-pass filter 4 shifts the phase of the LRF signal A at -45 deg., and on the other hand, a phase compensating circuit 5 shifts the phase of a track error signal (TE signal) 1 at +45 deg.. Therefore, difference between the phases of the LRF signal A and the TE signal 1 becomes 0 deg. and 180 deg. corresponding to an oscillating direction 10 of the lens. According to the level of the LRF signal A, the ON/OFF of a TE signal B inverting the TE signal is alternately repeated and a brake signal D is formed to be operated in the reverse direction of the pickup lens oscillation direction 10. Then, when moving an actuator, the oscillation of the pickup lens is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is an optical system that quickly converges natural vibrations that occur when an optical pickup lens crosses a bit string in a signal reading device such as a CD that uses an optical pickup. This invention relates to a vibration brake circuit for a pickup lens.

[Conventional technology]

CD player, LD player, CDV player, CD-ROM player, CDI player, CDW
, ○, Player, CDM, O, Player, etc., in electrical/electronic equipment that uses optical pickups, magneto-optical pickups, etc., when controlling the movement of the pickup in the tracking direction, the pickup The pickup lens causes self-vibration due to its natural vibration frequency, and until this vibration converges, the pickup operation becomes uncontrollable and a blank period occurs in the player's function.

As a means of damping the above-mentioned vibration, a sampling mark bit is provided with the position shifted by 1/4 trunk pinch back and forth with respect to the trunk center, and the change in the amplitude phase when the pickup crosses the sampling mark pit and the positive focus is A method of detecting the relative movement direction between the big amplifier and the track position on the disk and applying a tracking error signal only in the direction that suppresses the vibration of the pickup, and a method of differentiating the tracking error signal to detect the relative movement direction between the pickup objective lens and the track position. A means for outputting a one-way speed signal between the track error and the track error.

A method has been adopted in which the objective lens is converged in a direction in which the difference between the two signals becomes zero by means of outputting a command speed signal when the robot jumps the track, but none of these methods are sufficient.

In addition to the above-mentioned technical factors, the use of elements such as A/D and D/A converters is essential, and the number of parts included in the device is large, resulting in a lot of waste.

[Problem that the invention seeks to solve]

Hikari Pi and Kuasop have vibrations that cross at least several hundred trunks back and forth before stopping at the scheduled stop trunk.
If there is eccentricity in the disk when this vibration stops, it becomes even more difficult to deal with it using conventional control techniques.

Furthermore, the larger the resonance peak Q that the vibrating body inherently has, the more difficult it becomes to control it.

The conventional control method using reflected light, which sets an idle time, stops the servo during that time to suppress vibration, and then restarts the servo after the idle time, is not effective because the vibration of the float-supported head has not stopped. Vibration makes the above control difficult, and timing discrepancies result in it taking several seconds for the pickup lens to stop.

[Means for solving problems]

In order to solve the above problems, the present invention provides a reproduction signal (
2) LRF signal generation circuit with DC components removed (3)
The LRF signal (A) is passed through a low pass filter (4
), the phase shifts by 45″, while the TE multiplied signal 1)
By shifting the phase of L by +45° using the phase compensation circuit (5), the above L
The phase difference between the RF signal (A) and the TE multiplied signal is 0° and 18
By using the fact that the angle is 0°, the LRF signal (A) having the above phase difference corresponds to the off-track position of the pickup lens by using the switch (11) which is turned on and off depending on the level of the LRF signal (A). When outputting a certain value or more, drive the TE multiplied signal whose phase has been shifted by +45° and further invert the signal (B) to output the LRF signal (
If A) is less than the above certain value, the TE multiplication signal is turned off.
By doing this, the inverted TE multiplied signal B) is turned ON--OFF.
are repeated alternately, and the pickup lens vibration direction (10
), which acts in the opposite direction to the brake signal CD), and the phase difference O0 and 180° of the brake signal (D)
By outputting inward signals and outward signals of tracking corresponding to the vibration position (10) of the pickup lens by the switch (11), vibration of the pickup lens during movement of the actuator is suppressed. ,
We have developed a vibration brake circuit for optical pickup lenses that promotes smooth displacement against tracking.

At this time, in order to prevent the servo from locking on the off-track due to the low frequency components contained in the inverted TE multiplied signal B), the inverted TE multiplied signal B) is filtered through a high pass filter (7) in advance. Pass it through the filter to remove the low frequency components.

The brake signal (D) of the present invention with the above configuration has a structure in which the basic unit alternately repeats ON-OFF-ON-0FF, so excessive movement of the pickup lens is suppressed and smooth displacement with respect to tracking is achieved. It becomes possible to encourage

[Operations and Examples] FIG. 1 is a block diagram showing the configuration of the vibration brake circuit of the optical pickup lens of the present invention, and FIG. Shows the relationship between signals.

In Fig. 1, the phase of the outputted TE multiplied signal 1) is advanced by +45° by a phase compensation circuit (5), and the polarity of the TE multiplied signal 1) is reversed by an inversion calculation circuit (6) to produce an inverted TE signal. After forming the double signal B), the high bass filter (7) cuts the (li frequency).

By this operation, it is possible to prevent the phenomenon in which the servo is locked on off-track due to the low frequency component contained in the inverted TE multiplied signal B).

On the other hand, the position of the laser spot on the pickup lens (
10) is detected, a DC component is removed from the reproduced signal (2) to form an LRF signal (A), and the LRF signal (A) indicating 0 to 1.1V is passed through a low pass filter (4). By passing it through, the phase is shifted by 45 degrees.

As a result of the above operation, the phase difference of ±90° originally between the TE multiplied signal 1) and the LRF signal (A) becomes 06 and 180°, respectively, which correspond to the outward or inward signals of the track.

Therefore, when the lens jumps across the track during a search operation, if the TE multiplication signal 1) is turned off when the level of the LRF signal (A) is 0.6 V or more, the lens will move in the direction across the track. Signals with different polarities and level differences depending on the vibration speed are obtained.

In this case, when the LRF signal (A) outputs 0.6 V or more corresponding to the off-track position of the pickup lens, the inverted TE multiplied signal B) is driven by switching (11) by the comparator (8), Said LR
When the F signal (A) is 0.6 V or less, the inverted TE multiplied signal B is activated by the switch (11) by the comparator (8).
) is turned OFF and the inverted TE multiplied signal ON--OFF is alternately repeated to form a brake signal (D) that acts in the opposite direction to the vibration direction of the pink amplifier lens.

In addition, in the figure, the control circuit (12) is controlled by the function of the microcomputer.
It has a function of determining the ON--OFF timing of the tracking servo.

Figure 2 shows the relationship between the above signals.
The comparator output LRF signal waveform when the signal (A) shows 0.6V or more is shown in (C), and the brake signal (D)
adopts a configuration in which + (or -) ON portions and flat OFF portions of the sin curve are alternately repeated. In this diagram,
Only one of the phase difference of O'' or 180° is shown.

With the above configuration, when the laser spot is located off-track and the level of the LRF signal (A) is high, an inverted TE multiplied signal B) with a phase difference of 0'' and 180° is generated with respect to the LRF signal (A). By adding it to the regular tracking servo loop, it is possible to apply a voltage that imparts a force in the opposite direction to the vibration of the lens.

As shown in the diagram, the brake signal (D) has a structure in which the basic units alternately repeat ON--OFF-ON-OFF, so excessive movement of the pickup lens is suppressed and smooth movement for tracking is promoted. becomes possible.

Furthermore, as shown in the figure, the brake signal (D) has the advantage that the fluctuation width of the input brake voltage decreases and converges, making it easier to start the servo of the pickup lens at the target position.

〔Effect of the invention〕

The vibration brake circuit of the optical pickup lens of the present invention allows for phase compensation, whereas conventional control circuits require a large number of elements such as sample and hold, A/D and D/A converters. A vibration brake circuit for an optical pink amplifier lens can be constructed simply and at low cost by combining existing components such as circuits, inverting arithmetic circuits, and filters.

In addition, by replacing the vibration brake circuit of the optical pickup lens of the present invention with a high bass filter, etc., control by microcomputer software is unnecessary, so special software and software and microcomputer output ports are omitted. It is possible.

Furthermore, even if an optical pickup having an actuator structure with a large peak natural frequency is used, rapid control is possible as in the case of a pink-up with a small natural frequency.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a vibration brake circuit for an optical pickup lens according to the invention, and FIG. 2 shows the relationship between signals used in the vibration brake circuit for an optical pickup lens according to the invention. (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (A) (B) (C) (D) TE times Signal raw signal LRF signal generation circuit Low pass filter phase compensation circuit Inversion calculation circuit High bus filter Comparator drive circuit Lens displacement switch control circuit LRF signal inversion TE multiplication signal Amplifier output LRF signal waveform Brake signal

Claims (1)

[Claims] ON-OF of optical pickup lens to truck
The position of the laser spot is detected by the intensity of the reflected light associated with F. A signal obtained by removing the DC component from the reproduced signal (hereafter L
RF signal) with a low pass filter to change the phase to −
By moving the phase of the track error signal (hereinafter referred to as TE signal) by +45° using a phase compensation circuit, the phase difference between the LRF signal and the TE signal can be changed to 0° or 0° depending on the vibration direction of the lens. By utilizing the fact that the angle is 180°, when the LRF signal having the above-mentioned phase difference outputs a certain value or more corresponding to the off-track position of the pickup lens, by using a switch that is turned on and off depending on the level of the LRF signal, A signal obtained by further inverting the TE signal whose phase has been shifted by +45° is driven, and the LRF
If the signal is below the certain value above, turn off the TE signal.
By doing so, the inverted TE signal is alternately turned on and off to form a brake signal that acts in the opposite direction to the pickup lens vibration direction, and the tracking part corresponding to the phase difference of 0° and 180° of the brake signal is generated. Optical type that suppresses the vibration of the pickup lens when the actuator moves and promotes smooth displacement with respect to tracking by outputting the direction signal and the outward signal according to the vibration position of the pickup lens according to the switching. Vibration brake circuit for pickup lens.