| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical disk unit capable of preventing an optical disk from being damaged even in a failure in the pulling-in of a focus servo. SOLUTION: In this optical disk unit 100, an arithmetic circuit 118 outputs the intensity SUM of laser beams reflected at the optical disk 10 to a decision circuit 120 and outputs a focus error signal FE due to an astigmatism method to a focus control circuit 150. In a failure in the pulling-in of the focus servo of an objective lens 115, the intensity SUM of the laser beams falls below a maximum value, and when the intensity SUM of the laser beams becomes lower than a prescribed level, the decision circuit 120 outputs a stop signal STP for stopping the focus servo to the focus control circuit 150. The focus control circuit 150 controls a servo circuit 160 so as to stop the focus servo of the objective lens 115, and the servo circuit 160 stops the pulling-in operation of the focus servo.
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