JPH01105334A - Optical pickup driving device - Google Patents

Abstract

PURPOSE:To stabilize the shift position after a tracking jump by making an instruction speed signal and a tracking error direction speed signal jump in a direction in which the level difference of a differentiated tracking error signal becomes zero. CONSTITUTION:When a starting signal is impressed, switches 6 and 7 are respectively turned on and off by a logic circuit 9, and an actuator circuit 10 is switched to a tracking jump speed control loop. Further, the tracking error direction speed signal passing through a differentiating circuit 11, LPF 13, and polarity converting circuit 15 and the level difference signal of the instruction speed signal passing through a time constant circuit 14 and a polarity converting circuit 16 are supplied through a switch 7, and the circuit 10 makes an objective lens tracking-jump for one time in the direction in which the difference signal becomes zero. Thus, the objective lens moves at constant speed for the first half of the tracking jump, the speed is gradually and exponentially decreased for the latter half, at the time of the jump completion, the speed becomes zero, the shift position after the jump is stabilized, and the position accuracy of the objective lens is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical pickup drive device installed in optical recording/reproducing equipment and the like.

(Prior Art) Fig. 3 shows the configuration of a conventional track control circuit in an optical pickup drive device, in which 1 is a bang-bang control section that performs tracking control using a Bang-Bang control method; and 3 are switches for switching between outer circumferential direction acceleration and inner circumferential direction acceleration in the bang/bang control unit 1. Switching of switches 2 and 3 is performed by a binary tracking error signal (TE ), and the ON states of switches 2 and 3 are managed by time. 5 is a multiplexer that switches between forward jump and back jump according to input jump direction signal (DIR);
6 and 7 are switches for switching between position control during track following and bang-bang control during track jump; the switches 6 and 7 are operated by a start signal (START) input to the logic circuit 4.

8 is to prevent switches 6 and 7 from being turned on at the same time.
This is an inverter inserted between the logic circuit 4 and the switch 7.

In the conventional example configured in this way, the conventional bang
In the bang type tracking control, by appropriately setting the acceleration time toward the inner circumference or the acceleration time toward the outer circumference (see tracking signal TK in FIG. 4), it is possible to cause the objective lens to jump by one track.

(Problem to be solved by the invention) However, in the conventional tracking control using the bang-bang method, the objective lens is controlled to be open, so the movement position of the objective lens after a track jump becomes unstable, and the position There was a problem that control accuracy deteriorated.

The present invention has been made in view of such problems, and it is possible to stabilize the movement position of the objective lens after a track jump, and
It is an object of the present invention to provide an optical pickup control device that improves the accuracy of position control of an objective lens.

(Means for Solving the Problems) In order to achieve the above object, the present invention is a means for differentiating a track error signal and outputting a track error direction speed signal between an objective lens and a track of a recording medium. a means for outputting a command speed signal when performing a track jump; and a means for causing the objective lens to perform a track jump in a direction in which the level difference between the two speed signals is zero based on a difference signal between the track error direction speed signal and the command speed signal. It consists of

(Function) A difference signal between a track error direction speed signal obtained by differentiating a track error signal and a command speed signal having a time constant causes the objective lens to track jump in the direction where the level difference between both speed signals becomes zero. In other words, The objective lens jumps one track with a speed profile in which the speed is constant during the first half of the track jump, the speed gradually decreases during the second half of the track jump, and the speed reaches zero at the end of the jump. The movement position of the objective lens is stabilized, and the accuracy of objective lens position control is improved.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of the present invention, and the same reference numerals as those in FIG. 3 indicate the same parts.

Now, when the start signal (START) is input to the logic circuit 9 as a trigger pulse, the position/speed control switching signal (VEL) is output from the logic circuit 9, and the switch 6 is cut off and the switch 7 is turned on. , the actuator drive circuit 10 is switched from a track following position control loop to a track jumping speed control loop.

Therefore, the binarized tracking error signal (TE)
The objective lens of the optical pickup (
(not shown) [see output signal (A) of the low-pass filter circuit in FIG. 2), the time constant circuit 14 obtains a command speed signal having a time constant (see output signal (B) of the time constant circuit in FIG. 2).

Then, the polarity of the track error direction speed signal and the command speed signal, that is, the jump direction of the objective lens, is converted into a jump direction signal (DIR) by the polarity conversion circuits 15 and 16.
, and outputs a difference signal between the track error direction speed signal and the command speed signal. Based on the difference signal, the actuator drive circuit 10 moves the objective lens in the direction where the level difference between the two speed signals becomes zero. Jump one track.

At this time, the objective lens has a speed profile such that the speed is constant during the first half of the track jump, the speed gradually decreases exponentially during the second half of the track jump, and the speed becomes zero at the end of the jump. Jump one track.

(Effects of the Invention) As explained above, according to the present invention, the difference signal between the track error direction speed signal obtained by differentiating the track error signal and the command speed signal having a time constant is such that the level difference between the two speed signals becomes zero. Since the objective lens is track-jumped in the direction, the movement position of the objective lens after the track jump is stabilized, and the accuracy of the objective lens position control is improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a one-track jump method according to an embodiment of the present invention, FIG. 2 is a timing chart 1-1 of a one-track jump method according to an embodiment of the present invention, and FIG. 3 is a conventional bang-bang control. FIG. 4 is a block diagram of a one-track jump method using conventional bang-bang control. 9... Logic circuit, 10... Actuator drive circuit, 11... Differential circuit, 12... Double wave rectifier circuit, 13... Low pass filter circuit. IQ-Ll Rokumi (START) (TE) Tototsu Wabi-go (Be) Tracking Shin (TKI - Haichiichiichiichiichiichi)

Claims (1)

[Claims] In an optical pickup driving device that controls the position of an objective lens of an optical pickup so that a light beam follows a desired track on a disk recording medium, a track error signal is differentiated to means for outputting a track error direction speed signal between the tracks of the recording medium; means for outputting a command speed signal when making a track jump; and a difference signal between the track error direction speed signal and the command speed signal. An optical pickup driving device comprising: means for track-jumping the objective lens in a direction in which a level difference between both speed signals becomes zero.