Method and apparatus for compensating astigmatism in an optical storage system
AssigneeSunplus Technology Co., Ltd.
InventorsWen-Chun Feng, Chien-Liang Yeh
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Abstract
The present invention discloses a method and an apparatus for compensating astigmatism in an optical storage system. Firstly, the optical storage system focuses on an optical disc and proceeds track seeking. While track seeking, the astigmatism compensator continues adjusting and an astigmatism index signal is also measured. At last, an optimal astigmatism compensated value of the astigmatism compensator is acquired based on the measured result of the astigmatism index signal.
Claims6
A method for compensating astigmatism in an optical storage system, wherein the storage system comprises an astigmatism compensator, comprising:
- (a1) controlling the optical storage system focusing on an optical disc and proceeding track seeking;
- (a2) adjusting a compensated values of the astigmatism compensator and recording the compensated value as a AS0_T;
- (a3) measuring a peak-to-peak values of a main push pull signal in response to the AS0_T and recording the peak-to-peak value of the main push pull signal as a MPPpp_T;
- (a4) comparing the MPPpp_T with a MPPpp_Max stored in a memory;
- and
- (a5) setting a AS0_OPT equal to the AS0_T and setting the MPPpp_Max equal to the MPPpp_T if the MPPpp_Max is smaller than the MPPpp_T;
- wherein steps of (a1) to (a5) are executed a number of times to acquire a first optimal compensated value from the AS0_OPT for the astigmatism compensator to compensate an astigmatism AS0.
An apparatus for compensating astigmatism in an optical storage system, comprising:
- a control unit capable of adjusting a compensated values;
- an astigmatism compensator, connected to the control unit for compensating astigmatism in response to the compensated values;
- an optical pickup head, including a photo detector which generating a detector signal;
- an operation unit, connected to the optical pickup head for receiving the detector signal and generating a main push pull signal;
- a peak-to-peak value detector, connected to the operation unit for detecting a peak-to-peak values of the main push pull signal in response to the compensated values;
- a memory capable of recording a first peak-to-peak value and a first optimal compensated value;
- a logic comparison unit, connected to the peak-to-peak value detector and the memory, capable of receiving and comparing the peak-to-peak values of the main push pull signal and the first peak-to-peak value and setting the first optimal compensated value equal to the adjusted compensated value and setting the first peak-to-peak value equal to the peak-to-peak value of the main push pull signal if the first peak-to-peak value is smaller than the peak-to-peak signal of the main push pull signal;
- wherein the control unit is connected to the logic comparison unit and is capable of adjusting the compensated value a number of time and then providing the first optimal compensated value to the astigmatism compensator for compensating an astigmatism AS0 of the astigmatism compensator.
Dependencies are inferred from the claim text.