JPH03260919A - Tracking controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a tracking control device for an optical disk device or the like.

Conventional technology In recent years, technological advances in optical disk devices have been remarkable.

In this optical disk device, the tracking operation of scanning the trunk on the information medium is an important issue.

The configuration of a conventional tracking control device is shown in a block diagram in FIG. In FIG. 3, 1 is a tracking error detection means, 2 is a servo amplifier circuit, 3 is a loop switch, 4 is a tracking drive means, 5 is a tracking actuator, 6 is a pickup having an objective lens inside, and 7 is a traverse actuator. , 8 is a traverse drive means, 9 is a control means such as a microcomputer, 10
is an information medium that has track information inside.

Regarding the conventional tracking control device having the above-mentioned components, the mutual relationship and operation of each component will be explained. The operation when accessing a target trunk from an arbitrary track starts with a loop switch control signal from the control means 9. The loop switch 3 is opened and the tracking servo is placed in the oven state. Next, the control means 9 gives a drive command to the traverse drive means 8, and the traverse drive means 8 operates the traverse actuator 7 to move the pick amplifier 6 to the vicinity of the target track. When the pink-up 6 stops near the target track, the control means 9 sends the loop switch control signal to the loop switch 3 again, the loop switch 3 is closed, the tracking servo is pulled in, and when the servo operates normally, information is read. becomes possible,
You can move on to the next optional action.

Problems to be Solved by the Invention In such a conventional tracking control device, when the pickup 6 stops near the target track, the tracking servo is in the oven state. - The objective lens in the link-up 6 is in a vibrating state.

When the objective lens is in a vibrating state, it becomes difficult to restart the tracking servo, and the servo loop cannot be closed until the vibration has stabilized, requiring a waiting time.

Furthermore, if external vibrations are continuously applied, there is a risk that servo retraction may become impossible.

The present invention solves the above-mentioned problems, and even if the pick amplifier stops near the target track and external vibrations are applied when retracting the tracking servo, the vibration of the objective lens is suppressed and the servo can be retracted. The present invention aims to provide a tracking control device.

Means for Solving the Problems In order to solve the above problems, the present invention has a configuration in which, in addition to the conventional tracking servo loop, a cross speed detection means, a speed comparison means, and a speed loop inch are provided. be.

Operation With the above-described configuration, the present invention applies speed control to the objective lens when the traverse operation of the pick amplifier is stopped and external vibration is applied while the tracking servo loop is in an oven state.

Embodiment Hereinafter, a tracking control device according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

In FIG. 1, parts that are the same as those shown in FIG. 3 are given the same numbers and their explanations will be omitted.

In the figure, reference numeral 11 indicates cross speed detection means for detecting the relative speed at which the objective lens crosses the trunk of the information medium from the tracking error signal, and reference numeral 12 indicates the cross speed detection means 11.
13 is a speed loop switch which compares the speed signal outputted from the speed signal with a reference signal and outputs a speed control pulse.

FIG. 2 shows the output waveforms of the tracking error detection means 1 when the bind-up 6 stops during access and when external vibration is applied. (a) shows no speed control, (
b) corresponds to the case with speed control.

To explain the mutual relationship and operation of each of the above components, when accessing, when the pickup 6 stops near the target track, if there is external vibration, the objective lens inside the pickup 6 vibrates, so tracking error is detected. The output signal of the means 1 appears as a short track cross period waveform as shown in FIG. 2(a). With such a short cycle, it is difficult to pull in the tracking servo. In this embodiment, at this time, the speed loop switch 13 is closed by a command from the control means 9, and the tracking actuator 5 is subjected to speed control. The reference signal of the speed comparing means 12 is set to a zero speed signal, and the track crossing period is controlled to be zero. That is, the speed is controlled so that the speed at which the objective lens in the pickup 6 traverses the track in the information medium 10 becomes zero. With this control, even if the objective lens inside the pickup 6 tries to vibrate due to external vibration, the vibration is suppressed because velocity damping is applied, and the output waveform of the tracking error detection means 1 becomes as shown in FIG. 2(b). Trunking servo retraction is possible. After the servo pull-in starts, the speed loop switch 13 becomes open according to a command from the control means 9, and the vibration control ends.

As described above, according to the tracking control device according to the embodiment of the present invention, the cross speed detection means 11 is provided in addition to the conventional tracking control means, and the pickup 6 is detected to track the track based on the tracking error signal of the tracking error detection means 1. Speed comparison means 1
A speed loop switch 13 is provided to compare the cross speed and a reference speed (zero in this case) and output a speed control pulse (control signal) corresponding to the difference. In response to the stoppage of the pink amplifier 6, the speed fresh fish signal is manually input to the traverse drive means 8, and the traverse drive means 8 controls the objective lens so that the cross speed matches the reference speed in response to the speed control signal. By driving the servo, it is possible to suppress the vibration of the objective lens even if vibration is applied while the pickup is stopped during access operation.Therefore, this has the effect of preventing an increase in access time and the inability to retract the servo due to external vibration. can get.

Effects of the Invention As is clear from the above-described embodiments, the tracking control device of the present invention can be added to a conventional tracking/knocking control device equipped with a tracking loop including a tracking drive means and a tracking error detection means to detect a cross velocity. means, a speed comparison means, and a speed loop switch, and the cross speed detection means detects the speed at which the objective lens crosses the trunk, that is, the cross speed from the tracking error signal and outputs the detected speed to the speed comparison means. The speed comparison means compares the cross speed with a reference speed,
A control signal corresponding to the difference is outputted to the tracking drive means via the speed loop switch,
The control signal of the speed loop switch is connected to the tracking drive means in response to the start of an access operation, and disconnected in response to the start of servo retraction, and the tracking drive means manually inputs the control signal to control the cross speed. By driving the objective lens so that the speed matches the reference speed, the objective lens is controlled so that it does not move even if the pick amplifier receives external vibration while it is stopped during access operation, and the vibration of the lens is suppressed. is suppressed and the tracking error signal waveform does not include the influence of external vibrations, so it is possible to prevent increases in access time and inability to pull in the servo due to external vibrations.

[Brief explanation of drawings]

FIG. 1 shows I of a tracking control device according to an embodiment of the present invention.
FIGS. 2(a) and 2(b) are waveform diagrams of trunking error signals, and FIG. 3 is a block diagram showing the configuration of a conventional trunking control device. 1... Tracking error detection means, 2...
... Servo amplifier circuit, 3 ... Loop switch, 4 ... Tracking drive means, 5 ...
・Tracking actuator, 6...Pickup, 7...Traverse actuator, 8
... Traverse drive means, 9 ... Control means, 10 ... Recording medium, 11 ... Cross speed detection means, 12 ... Speed Comparison means, 1
3... Speed loop switch.

Claims (1)

[Claims] A pickup that optically reads information from a recording medium,
a tracking actuator that moves an objective lens in the pickup in a direction perpendicular to a track direction that is an information row of the recording medium; and a tracking actuator that is connected to the pickup to detect a positional deviation between the track and the optical spot of the pickup. a servo amplifier circuit for amplifying a tracking error signal generated by the tracking error detection means, and a loop switch controlled by a control means to control the actuator according to an output signal of the servo amplifier circuit. a tracking drive means for driving, a cross speed detection means for detecting the speed at which the light spot crosses the track from the tracking error signal, and cross speed information outputted from the cross speed detection means is compared with a reference speed. a speed comparison means for outputting a speed control pulse (control signal) to the tracking drive means via a speed loop switch; a traverse actuator for moving the pickup in a direction perpendicular to the track; and a control means for controlling the traverse actuator. The speed loop switch connects the speed control signal to the traverse drive means in response to the start of an access operation, and disconnects the speed control signal in response to the start of retraction of the tracking servo, The tracking control device is configured such that the tracking driving means drives the objective lens in response to the control signal input so that the cross speed matches the reference speed.