KR20030083116A - Method controling eccentricity of optical record media - Google Patents

Abstract

PURPOSE: An eccentricity control method for an optical recording medium is provided to compensate the eccentricity speedily and minimize the still existing errors by adding a sine wave shaped eccentricity to a tracking driving signal. CONSTITUTION: An eccentricity control method for an optical recording medium includes a TE generating part(101) for generating tracking error signals by electric signals(a-d) in proportion to the intensity of reflection light output from an optical pickup. The tracking error signals are processed by a TD driving part(102) for generating a driving signal(TD) for controlling the tracking. An eccentricity amount computation part(103) computes an eccentricity amount by the FG signals and FG(Frequency Generator) signals. A TD correcting part(104) generates a final tracking driving signal(TD') by adding the computed eccentricity amount to the TD signals.

Description

Method of controlling eccentricity of optical record carrier

The present invention relates to a method of controlling the amount of eccentricity using rotation information of an optical recording medium.

In general, an optical recording medium, that is, an optical disc recording and reproducing apparatus for recording and reproducing an optical disc, reproduces data recorded on the optical disc using an optical disc such as a compact disc (CD), a digital versatile disc (DVD), or the like as a recording medium. And a device for recording data on the disc.

In this case, the rotation information of the disk may be detected from a frequency generator (FG) signal generated when the spindle motor rotates. In this case, the number of FG signals generated per one revolution of the disc may vary from designer to designer. In general, the number of FG signals generated per revolution of the disc is six.

The optical disk may be distorted during the injection and curing of the resin in the manufacturing process, thereby causing an eccentricity even when a central hole is drilled. Further, even if the disc track is accurately recorded in a spiral shape at a pitch of a predetermined standard, an eccentricity is generated because the center hole is varied. Thus, the disk rotates with eccentricity, so it is difficult for the central axis of the motor and the center of these tracks to completely coincide. In other words, the original disc center and the track center are shifted.

In particular, there is a disc eccentricity caused by disc manufacturing, an eccentricity generated when mounting a disc, and an eccentricity caused by run-out of a rotating shaft, and the amount of run-out of an optical axis is relatively very large compared to the eccentricity caused by the preceding two factors. small.

Because of this, it is difficult to read exactly the signal of the desired track exactly, so the eccentricity must be controlled. In particular, if the eccentricity is not controlled, the seek time is long because the track seek is performed several times to find the desired position due to the fine seek due to the incorrect seek position.

Therefore, conventionally, the amount of eccentricity is calculated in advance and used at the time of free running, and after the on-track, the eccentricity is followed depending on the tracking filter.

Here, the free running state means detecting a servo error signal while the disk is rotated and the optical pickup is fixed while the tracking servo is turned off and only the focus servo is turned on. The free running state is mainly used for measuring the eccentricity of the disk.

However, the conventional eccentricity control method described above may have a difference in the amount of eccentricity depending on the disc position at the on-track time point after the rough seek since the average value is used on track after roughly calculating the eccentricity in pre-running. . That is, the inner and outer eccentric amount on the disk may be different. Since the same value is applied to all positions on the disk with the previously obtained average value, the target position at the time of seek may be moved to the wrong position when the eccentric amount is not measured. For this reason, in order to go to the target position, several seek operations may be performed unnecessarily. That is, there is a problem in that an error with respect to the seek position is large, which greatly affects the access time delay.

In addition, since the eccentricity is tracked after the on-track depending on the tracking filter, the eccentric tracking can be greatly influenced by the performance of the tracking filter. In other words, if the performance of the filter is poor, there may be a case where there is a large amount of eccentricity or when another disk is inserted, it cannot follow the eccentricity.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, and an object of the present invention is to generate a sinusoidal eccentric amount using rotation information and a TZC signal and always add it to a tracking drive signal to compensate for the eccentric amount. To provide an eccentric control method of.

1 is a configuration block diagram of an eccentric control device according to the present invention

2 is an operation waveform diagram of each part of FIG.

Explanation of symbols for main parts of the drawings

101: TE generation unit 102: TD drive unit

103: eccentricity calculation unit 104: TD compensation unit

Eccentric control method of the optical recording medium according to the present invention for achieving the above object, generates a tracking error signal using an electrical signal proportional to the amount of reflected light output from the optical pickup, driving tracking from the tracking error signal An eccentric control method of an optical recorder for generating a signal to drive a tracking actuator, the method comprising: dividing one rotation of the optical recorder into a plurality of sections from rotation information of the optical recorder, and continuously increasing the same section; or Generating an eccentric change curve by continuously decreasing the eccentric change curve; and generating a final tracking drive signal by adding the eccentric change curve generated in the step to the tracking drive signal, and then driving the tracking actuator. It is characterized by.

The step may be characterized by dividing one rotation of the optical recording medium into four sections based on the FG signal generated when the optical recording medium is rotated.

The eccentric change curve is increased by a predetermined amount every time the tracking zero crossing (TZC) point is detected during the first quarter of rotation, and the eccentric change curve is increased each time the TZC point is detected during the next quarter of rotation. Decreases by a predetermined amount, decreases the eccentricity change curve by a preset amount every time the TZC point is detected during the next quarter of rotation, and sets the eccentric change curve by the preset amount every time the TZC point is detected during the next quarter of rotation. It is characterized by generating an eccentric change curve by increasing by a predetermined amount.

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, with reference to the accompanying drawings illustrating the configuration and operation of the embodiment of the present invention, the configuration and operation of the present invention shown in the drawings and described by it will be described as at least one embodiment, By the technical spirit of the present invention described above and its core configuration and operation is not limited.

The present invention divides the FG signal generated by one rotation of the spindle motor into a plurality of sections, and forms a sine wave by increasing or decreasing the eccentricity signal whenever TZC is detected in each section. The sine wave generated in this way is set as the eccentric amount and is always added to the tracking drive signal to drive the tracking actuator to perform real time eccentric control.

FIG. 1 is a block diagram illustrating the configuration of an eccentricity control device according to the present invention. The TE generating unit generates a tracking error signal using an electrical signal (a, b, c, d) proportional to the amount of reflected light output from an optical pickup. 101), a TD driver 102 generating a drive signal (TD) for tracking control by processing the tracking error signal, an eccentricity calculator (103) for calculating an eccentricity from the FG signal and the TE signal, and the TD signal And an eccentric amount to generate a final tracking drive signal TD '.

The present invention configured as described above measures the amount of eccentricity in the free running state. That is, during free running, the TE generation unit 101 uses the tracking error signal by using the electrical signal (a, b, c, d) that is proportional to the amount of reflected light output from the photo detector in the optical pickup. Generate TE signal as in a). The TE signal is output to the TD driver 102 and the eccentricity calculation unit 103. The TD driver 102 processes the TE signal to generate a tracking drive signal TD for driving the tracking actuator as shown in FIG. 2C, and outputs the tracking drive signal TD to the TD corrector 104.

In addition, an FG signal such as (b) of FIG. 2 generated while the spindle motor rotates is also input to the eccentricity calculation unit 103 for the eccentricity calculation.

The eccentricity calculation unit 103 generates an eccentric curve as shown in FIG. 2 (d) by using the TE signal and the FG signal.

That is, the eccentricity calculation unit 103 divides the FG signal generated when one spindle motor rotates into a plurality of sections. In the present invention, as shown in FIG. Here, dividing one rotation of the disk into four quarters is because the phase can be known immediately.

After setting the reference point of the FG signal, the eccentric curve is increased by a fixed amount for a quarter of a turn from the reference point, and decreased by a certain amount during the next quarter of the rotation, and decreased by a certain amount during the next quarter of rotation. During quarter revolutions, an eccentric curve is generated by a certain amount.

Here, the reference to increase or decrease uses the TZC signal. That is, each time the TZC point is detected in the corresponding section, the eccentric curve is increased or decreased by a predetermined amount. For example, if the current section is an increasing section, each time the TZC point is detected, the eccentric curve is increased by a predetermined amount.

The TZC signal may be obtained by slicing the tracking error signal TE to an internal reference level. That is, the tracking zero crossing signal TZC is a signal that is turned on / off at the track cross time.

FIG. 2 (d) shows a sinusoidal change curve in the eccentric change curve at the time of one disc rotation detected from the FG signal and the TZC signal by the above-described process.

The sinusoidal eccentric change curve becomes an actual amount of eccentricity and is output to the TD corrector 104.

At this time, the TD correction unit 104 adjusts the phase of the eccentric curve output from the eccentricity calculation unit 103 after extracting the effect of the actual eccentricity on the track from the track drive signal after the on track. That is, since the eccentric curve calculated by the eccentricity calculation unit 103 is an eccentric change curve during one disc rotation from an arbitrary position, the eccentric curve is adjusted so that the phase is the same as the actual eccentric influence curve.

Then, the phase-controlled sinusoidal eccentric change curve is phase shifted by 180 degrees and then added to the tracking drive signal TD to generate a final TD signal TD '.

The final TD signal TD 'drives the tracking actuator in the optical pickup to move the objective lens of the optical pickup in the radial direction to correct the position of the beam and follow a predetermined track.

The present invention controls the tracking actuator according to the eccentric curve even during seek (i.e., tracking off, focus off), thereby minimizing the effect of eccentricity and ensuring stability of track control. In other words, it is possible to minimize the movement to the wrong target position during seek.

In particular, by easily discriminating the phase relationship between the actuator and the track during seek, i.e., the outer circumferential direction or the inner circumferential direction, auto brake can be performed without the help of other signals to ensure on-track stability.

As described above, according to the method of controlling the eccentricity of the optical recording medium according to the present invention, the amount of eccentricity in the form of sinusoids generated by using the rotation information and the TZC signal is always added to the tracking drive signal, thereby quickly compensating and maintaining the eccentricity. The error can be minimized. In particular, the seek performance can be improved by reducing the seek position error due to the eccentricity during seek. In addition, since the contribution of the tracking filter can be minimized, flexibility in designing the tracking filter can be ensured.

Also, since the phase information and the low frequency point can be known using the sine wave, the actuator break point for on-track can be accurately known without the aid of an auxiliary signal such as a mirror signal.

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 (4)

An eccentric control method of an optical recorder for generating a tracking error signal using an electrical signal proportional to an amount of reflected light output from an optical pickup, and generating a tracking drive signal from the tracking error signal to drive a tracking actuator. (a) dividing one rotation of the optical recording medium into a plurality of sections from the rotation information of the optical recording medium; (b) generating an eccentric change curve by performing a continuously increasing or decreasing process in the same section; And and (c) adding the eccentric change curve generated in the step to the tracking drive signal to generate a final tracking drive signal and then driving the tracking actuator. The method of claim 1, wherein step (a) Eccentric control method of the optical recording medium, characterized in that divided into four sections during one rotation of the optical recording medium on the basis of the FG signal generated when the optical recording medium is rotated. The method of claim 2, wherein step (b) During the first quarter of the rotation, the eccentricity change curve is increased by a predetermined amount each time the tracking zero crossing (TZC) point is detected, and during the next quarter of the rotation, the eccentricity change curve is set every time the TZC point is detected. Decrease by a certain amount, and reduce the eccentricity change curve by a predetermined amount each time a TZC point is detected during the next quarter of rotation, and during the next quarter of the turn, the eccentric change curve is decremented by a predetermined amount each time the TZC point is detected. Eccentric control method of the optical record carrier, characterized in that for increasing the eccentric change curve. The method of claim 1, wherein step (d) And shifting the sinusoidal eccentric change curve by 180 degrees and adding the tracking drive signal to a tracking drive signal to generate a final tracking drive signal.