Focus error signal correction system and method

Abstract

The invention relates to a focus error signal correction system and a method. A primary light-receiving part generates a primary focus error signal, and a secondary light-receiving part generates a secondary focus error signal which is opposite in phase from an interference signal. A gain unit gains the corrected primary focus error signal, an amplifier adds the gained primary focus error signal with the secondary focus error signal, so that a focus error signal to be corrected is formed, and a control unit controls a correction unit to carry out correction in order to reduce the difficulty of correcting the secondary focus error signal.

Description

technical field [0001] The invention relates to a focus error signal correction system and method, in particular to a correction system and method for adjusting the vertical symmetry and size of the focus error signal by an optical disc drive to meet the requirements of servo control. Background technique [0002] The optical disc drive uses the optical pickup head to project a light beam to the disc, and detects the reflected light from the disc to form a focus error signal, locks the optical pickup head and the disc to maintain a certain distance range, and makes the focus of the projected beam fall on the disc . Through the intensity of the reflected light of the disk marks, an electrical signal representing the numbers 0 and 1 is formed with relative strength to read and write the data marks on the disk. [0003] Such as figure 1 As shown, it is the prior art disclosed in Taiwan Patent Application No. 09112808 "Focus Control Apparatus and Method". In this prior art, t...

AI Technical Summary

Problems solved by technology

Because the size of the interference signal is smaller than the main focus error signal MFE, although it has an impact on the correction of the main focus error signal MFE, the correct correction can still be achieved roughly.

[0006]However, the relatively weak sub-focus error signal SFE of the interference signal is quite large enough to affect the correction of the sub-focus error signal SFE, increasing the difficulty of correction, often resulting in Calibration failure or error

The signal strength and level of the sub-focus error signal SFE cannot be corrected to be consistent and up-and-down symmetrical. During servo control, the tracking error signal and focus error signal are often wrong, causing the servo system to swing violently and reducing the stability of the closed-loop control.

Therefore, there are still problems to be solved urgently in the correction of the focus error signal of the known optical disc drive

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