| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that the object lens collide with the optical disk since the working distance of the object lens decreases according to the short focusing of the object lens. SOLUTION: When setting a focus servo to a recording surface 2 of an optical disk 1, after setting a focus servo to a substrate surface 3 of the optical disk 1, the focus servo is set to the recording surface by moving the focus servo setting position to the recording surface of the optical disk 1 by a focus jump control circuit 12. Moreover, when abnormality in the setting of the focus servo is detected, after outputting a signal of a direction where an object lens 4 keeps away from the optical disk 1 to a focus actuator 5 from an object lens retracting control circuit 14 for the specified time, the signal of the direction where the object lens 4 approaches the optical disk 1 is outputted for the specified time.
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