| 摘要 |
PROBLEM TO BE SOLVED: To regulate generation of bounce back and vibration of an objective lens when focus servo off is detected. SOLUTION: The focus servo control unit comprises an objective lens 2a, an objective lens driving section 11, a signal producing section 6 for producing a focus error signal and a light intensity sum signal, a focus servo off determination section 9a for determining as focus servo off when the focus error signal or the light intensity sum signal meets a prescribed condition, an objective lens retract control means 9b for outputting an acceleration and deceleration control signal to the objective lens driving section 11 when the focus servo is off, a bias output determining section 9c for determining a bias voltage by reading a lapse time and the bias voltage from a storing section 8 which stores the bias voltage defined to offset the vibration of the objective lens and the associated lapse time, and an objective lens vibration controlling means 9d for outputting a bias control signal to control with the determined bias voltage to the objective lens driving section 11. COPYRIGHT: (C)2008,JPO&INPIT
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