| 摘要 |
PROBLEM TO BE SOLVED: To realize exact focus pull-in in focus control of an optical disk with a high reproduction speed and a large wobbly surface. SOLUTION: The focus pull-in method for pulling in a light spot onto a recording layer of an optical disk comprises a process for outputting a search voltage in the direction in which an objective lens approaches to the focal surface of the optical disk to a focus actuator, a process for detecting that a focus error signal based on the light reflected from the optical disk reaches a predetermined signal level, a process for outputting a brake signal to a focus actuator when the focus error signal reaches the predetermined signal level, and a process for starting focus control after outputting the brake signal in a case of detecting zero crossing of the focus error signal, and the predetermined signal level is set based on a noise component of the reflected light detected beforehand. COPYRIGHT: (C)2006,JPO&NCIPI
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