KR100606671B1 - Method for actuator vibration preventing of optical record/player - Google Patents

Abstract

A method of preventing vibration of an actuator in an optical recording and reproducing system, the method comprising: detecting a signal caused by actuator vibration; determining whether the detected signal is a peak signal; And generating a control signal in a direction in which the vibration of the actuator is reduced for a time, and applying a control voltage in a direction opposite to the vibration direction at the point where the actuator's movement speed is the highest when the actuator is vibrated, thereby reducing the vibration of the actuator. By suppressing it quickly, since the focus servo does not drop at the time of seek, stable and fast seek can be performed.

Actuator, vibration

Description

Method for actuator vibration preventing of optical record / player

(A) and (b) of FIG. 1 are conventional waveform diagrams for detecting slab driving using a stepper motor and actuator vibration accordingly.

2 is a block diagram of an optical recorder according to the present invention.

3 is a flowchart showing a method of preventing actuator vibration in an optical recorder according to the present invention.

Figure 4 (a) is a conventional waveform diagram measuring the back electromotive force generated in the actuator coil in accordance with the vibration of the actuator

Figure 4 (b) is a waveform diagram of the present invention measuring the back electromotive force generated in the actuator coil in accordance with the vibration of the actuator

Figure 4 (c) is a waveform diagram showing an example of the control voltage applied to the actuator to suppress the actuator vibration as shown in (b)

Explanation of symbols for main parts of the drawings

201: optical disk 202; Optical pickup

203: encoder 204: LD drive unit

205: RF and servo error generation unit 206: data decoder

207: servo control unit 208: actuator vibration signal detection unit

209: focus servo driver 210: tracking servo driver

The present invention relates to a method for preventing vibration of an actuator in an optical recording and reproducing system.

In general, in order to read data recorded on an optical disc, such as a compact disc (CD), a digital versatile disc (DVD), or the like, it is necessary to go to the point where desired data exists. At this time, in order to reach the desired point on the optical disc, the laser beam generated in the pickup must be accurately moved from the current track to the target track to track the target track. This task is called seek (or search).

The seek operation calculates the number of tracks to the target track, and if the number of tracks to be jumped is hundreds to thousands of tracks or more, by moving the pickup motor near the desired track after moving the slad motor, the tracking actuator when the number of tracks remaining is less than several hundred tracks To find the track. Here, rough seek to move the track by moving the slad motor is referred to as rough seek, and fine seek to jump the track by moving the actuator.

At this time, as one of the methods to perform the seek quickly, the optical pickup is attached to the disk, that is, the focus is performed and the rough seek is performed by driving the slad, and then the tracking is acquired and the data is acquired. A fine seek process is performed to determine and locate the correct position.

Thus, when the seek is performed, the actuator inevitably generates vibration by an external force, or by a kind of inertia during and after the internal slad movement.

FIG. 1 illustrates an example of vibration of the actuator, and FIG. 1A is a waveform diagram illustrating voltages at both ends of the tracking actuator coil, that is, counter electromotive force generated in the coil of the actuator according to shaking of the actuator. b) shows an example of a driving pulse for moving the slad. The actuator generates vibration even when the slad starts to move, and also generates vibration even when stopped after the movement.

The vibration of these actuators eventually causes problems with focus and tracking servos and requires a lot of time to normalize again. In particular, if the shake of the actuator increases due to the fast seek, the focus may be reduced. If the focus drops, the slad starts to refocus after driving, and then the tracking is applied. However, since it takes a long time to focus, it takes a long time to turn on the tracking servo, and the seek becomes slow, and in the worst case, seek may be difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for preventing actuator vibration of an optical recorder which can stably suppress vibration of an actuator to perform stable seeking.

Actuator vibration prevention method of the optical recorder according to the present invention for achieving the above object comprises the steps of detecting a signal caused by actuator vibration, determining whether the detection signal is a peak signal, and the peak in the step If it is determined as a signal, characterized in that it comprises a step of generating a control signal in a direction in which the vibration of the actuator is reduced for a predetermined time.

The detecting of the actuator vibration signal may include detecting and amplifying a voltage according to actuator vibration from a tracking coil included in the actuator.

The present invention is to detect a waveform (signal) relating to actuator movement from a tracking coil included in the actuator, and to generate a control voltage in a direction in which the vibration of the actuator is reduced at the peak value of the signal.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of the optical recording and reproducing apparatus for preventing the actuator vibration according to the present invention, in which the optical pickup 202 has a light beam focused on the objective lens under the control of the servo controller 207. The light is reflected on the signal track, and the light reflected from the signal recording surface is condensed by the objective lens and then incident on the photo detector for detection of the focus error signal and the tracking error signal. The photo detector includes a plurality of photo detectors, and an electrical signal proportional to the amount of light obtained from each photo detector is output to the RF and servo error generator 205.

The RF and servo error generation unit 205 combines the electrical signals output from the optical detection element of the optical pickup 202 to combine RF signals for data reproduction, tracking error (TE) signals for servo control, and focus errors ( FE) to create a traffic light.

At this time, the RF signal is output to the data decoder 206 for reproduction, servo error signals such as FE and TE are output to the servo controller 207, and a control signal for data recording is output to the encoder 203. .

The encoder 203 encodes data to be recorded according to a control signal into a recording pulse of a format required by the optical disk 201, and then outputs the data to the LD driver 204. The LD driver 204 outputs the data to the recording pulse. The LD of the optical pickup 202 is driven at the corresponding recording power to record data on the optical disk 201.

In addition, when reproducing the data recorded on the optical disk 201, the data decoder 206 restores original data from the RF signal detected by the RF and servo error generation unit 205.

The servo controller 207 processes the FE signal to output a driving signal for focusing control to the focus servo driver 209, and processes the tracking error (TE) signal to track the driving signal for tracking control. Output to the servo driver 210.

At this time, the focus servo driver 209 moves the optical pickup 202 up and down by driving the focus actuator in the optical pickup 202 so that the optical disk 201 follows the vertical movement along with the rotation. That is, the focus actuator for driving the focused objective lens up and down, that is, in the focus axis direction, keeps the distance between the objective lens and the optical disk 201 constant according to the focus driving signal.

In addition, the tracking servo driver 210 modifies the position of the beam by moving the objective lens of the optical pickup 202 in the radial direction by driving the tracking actuator in the optical pickup 202, and follows a predetermined track. do.

On the other hand, when the seek command is input, as shown in FIG. 1 (a), the tracking actuator vibrates during the slad movement or after the movement is completed. Therefore, the vibration of the actuator must be suppressed in order not to drop the focus servo during the slad driving.

To this end, the signal detector 208 measures the counter electromotive force generated by the tracking coil according to the vibration of the actuator in the optical pickup 202 and outputs it to the servo controller 207. In this case, since the counter electromotive force is a minute voltage, the signal detector 208 amplifies the detected voltage and outputs the amplified voltage to the servo controller 207. In other words, when the current flowing through the tracking coil is converted into a voltage, this is the counter electromotive force generated by the tracking coil.
The servo control unit 207 suppresses the vibration of the actuator by using the counter electromotive force generated from the tracking coil, that is, the voltage across the coil.

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3 is a flowchart according to an embodiment of the present invention showing a process of suppressing vibration of an actuator in the servo controller 207. First, it is determined whether an actuator hold mode, that is, vibration of an actuator, is generated (step 301).

If it is in the actuator hold mode, it is determined whether the vibration direction of the current actuator is positive (step 302). Here, the detection of whether the vibration direction of the actuator is positive or negative is to suppress the vibration of the actuator by applying a voltage opposite to the detected direction, that is, a brake voltage.

At this time, the positive and negative are relative concepts. If the direction in which the detected voltage increases is set to positive, the direction in which the voltage decreases may be set to negative.

Therefore, if it is determined in step 302 that the vibration direction of the actuator is positive, the peak point is detected while sampling the signal in the positive direction (step 303).

Here, the peak point is a point at which the actuator's movement speed is the fastest when the actuator vibrates, that is, the point where the absolute voltage is greatest. If you look at the position, it is the peak voltage point that passes through the center of position of the actuator. Therefore, when detecting the peak point at the movement speed, the peak point can be detected by comparing the reference speed in advance. In addition, when detecting the absolute voltage, the peak point may be detected through comparison after setting the reference voltage in advance.

At this time, if it is determined in step 303 that the peak point is not detected, the voltage is being increased in the positive direction, so that the signal is detected by sampling the signal (step 304).

If it is determined in step 303 that the peak point is detected, it is checked whether a preset time has elapsed (step 305).

Here, the actuator vibrating in the positive direction vibrates in the negative direction again from the peak point. Therefore, when the peak point is detected, the brake voltage is applied in the direction of reducing the control voltage, that is, the vibration of the actuator, as shown in FIG. This shortens the actuator vibration time as shown in Fig. 4B. This means that the width and distance that the actuator vibrates is shortened.

At this time, since the swing width of the generated voltage is different according to the shaking width of the actuator, the magnitude and time of the control voltage are determined according to the shaking amount, that is, the shaking width and the frequency of the actuator.

On the other hand, if it is determined in step 306 that the preset time has not elapsed, the time is checked while continuing to output the control voltage for the positive swing (step 306). If it is determined that the preset time has elapsed, the output of the control voltage is stopped and zero. A cross point is detected (step 307).

If the zero cross point is not detected in step 307, the loop is looped until it is detected (step 308), and if the zero cross point is detected, the actuator vibration direction is negatively set to perform a process opposite to that described above (step 309).

Therefore, when the vibration direction of the actuator is negatively detected in step 302, steps 310 to 316 are performed to detect the peak point in the negative direction, and when the peak point is detected, the control voltage is applied for a predetermined time for negative swing. Zero crossing is detected. Here too, the position at which the control voltage is applied is the point where the actuator's movement speed is highest when the actuator vibrates.

This process can reduce the vibration of the actuator in a short time. That is, Figure 4 shows an example, (a) is a waveform diagram for detecting actuator vibration before the present invention is applied, (b) is a waveform diagram for detecting actuator vibration after the present invention is applied. (c) shows the control voltage at this time.

According to the present invention, even if the control voltage is applied only once, the vibration of the actuator can be suppressed by a desired size, and the vibration of the actuator can be suppressed by applying the control voltage at least 2-3 times.

In particular, the present invention can stably turn on the tracking servo in a short time by applying the present invention when the slad starts or moves and stops when the slad is driven.

As described above, according to the actuator vibration prevention method of the optical recorder according to the present invention, by suppressing the vibration of the actuator by applying a control voltage in the opposite direction of the vibration direction at the point where the actuator's movement speed is the highest when the actuator vibrates Therefore, since the focus servo is not dropped during seek, stable and fast seek can be performed.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (14)

In the actuator vibration prevention method of the optical recorder to suppress the vibration when the actuator occurs, Detecting a back EMF signal generated from a coil included in the actuator according to the actuator vibration; Determining whether the detection signal is a peak signal; And generating a control signal in a direction in which the vibration of the actuator is reduced for a predetermined time when it is determined as the peak signal in the step, and applying the control signal to the actuator. The method of claim 1, wherein the detecting of the back EMF signal according to the actuator vibration is performed. And detecting and amplifying a voltage according to the actuator vibration from a tracking coil included in the actuator. The method of claim 2, wherein the determining the peak signal And detecting the peak signal when the voltage detected from the tracking coil is greater than a predetermined reference value. The method of claim 1, wherein the determining the peak signal And a peak signal if the actuator's movement speed is higher than a predetermined reference speed when the actuator vibrates. The method of claim 1, wherein generating the control signal And a peak signal is detected in the positive direction, and a control signal is applied to the positive direction at a point in time when the peak signal is detected in the positive direction. The method of claim 1, wherein generating the control signal And a control signal is applied for a predetermined time in the negative direction when the peak signal is detected when the peak signal is detected in the negative direction. The method of claim 1, wherein generating the control signal Actuator vibration prevention method of the optical recorder, characterized in that for determining the size and time of the control signal according to the vibration width and frequency of the actuator. The method of claim 1, wherein generating the control signal Stopping the output of the control signal after a predetermined time and detecting the zero cross point; Setting an actuator vibration direction in a direction opposite to an actuator vibration direction when the peak signal is detected when the zero cross point is detected; Detecting a peak signal while sampling the signal in the set vibration direction; The method may further include generating a control signal in a direction in which the vibration of the actuator is reduced for a predetermined time and applying the control signal to the actuator when the peak signal is determined in the step. The above-described process may be repeated for a predetermined number of times. Actuator vibration prevention method of an optical recorder. In the actuator vibration prevention method of the optical recorder to suppress the vibration when the actuator occurs, Detecting a vibration direction when vibration of the actuator occurs; Detecting a peak point while sampling a counter electromotive force signal according to the actuator vibration in the direction detected in the step; And generating a brake voltage in the detected vibration direction for a predetermined time when the peak point is detected in the step, and applying the brake voltage to the actuator. 10. The method of claim 9, wherein the peak point detection step is And a peak point is detected by measuring back EMF generated from a coil included in the actuator according to the vibration of the actuator. The method of claim 10, wherein the peak point detection step And determining the peak point if the absolute value of the counter electromotive force detected from the coil is larger than a preset reference value. The method of claim 10, wherein the peak point detection step And if the movement speed of the actuator is higher than a predetermined reference speed when the actuator vibrates, determining the peak point. The method of claim 9, wherein the step of generating the brake voltage And determining the magnitude and time of the brake voltage according to the vibration width and frequency of the actuator. The method of claim 9, wherein the step of generating the brake voltage Stopping the application of the brake voltage and detecting a zero cross point after a predetermined time elapses; Setting an actuator vibration direction in a direction opposite to the actuator vibration direction detected in the step when the zero cross point is detected; Detecting a peak point while sampling a signal in the set vibration direction; And generating a brake voltage in the set vibration direction for a predetermined time when the peak point is detected in the step, and applying the brake voltage to the actuator, wherein the above-described process is repeated for a predetermined number of times. Actuator prevention method of the regenerator.

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