Method and device for timely outputting focusing completion signal to realize focusing condition of optical pickup head
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United States of America Patent
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Apr 25, 2006
Grant Date -
Aug 28, 2003
app pub date -
Sep 20, 2002
filing date -
Feb 26, 2002
priority date (Note) -
Expired
status (Latency Note)
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Abstract
A method is provided for outputting a focusing completion signal to realize a focusing condition of an optical pickup head for an optical access apparatus. The method is described as follows. A trace shift of the optical pickup head along a focusing direction is actuated in response to a focus control signal when a focus adjustment operation starts. Then, a focusing error signal and a sub-beam addition signal are generated in response to optical signals from the optical pickup head. A closed-loop enable signal is generated to enable a closed-loop control operation in response to a specified situation of the focusing error signal. The focusing completion signal is outputted when the sub-beam addition signal is at a level greater than a threshold value and when the closed-loop enable signal is generated.
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