| 摘要 |
PROBLEM TO BE SOLVED: To inexpensively perform stable pull-in operation even when an external vibration occurs by directly detecting a speed of an objective lens in the focus direction caused with the external vibration and the speed in the tracking direction and operating an actuator controller so as to reduce respective speeds. SOLUTION: A focusing back electromotive voltage detection means 12 detects a back electromotive voltage generated on a focus actuator 3, and a focusing speed control means 13 generates a focus speed control signal so as to reduce the speed of the objective lens 2 in the direction vertical to a disk surface 1 based on the detection result to send it to a second focusing switching means 14. Further, a tracking back electromotive voltage detection means 22 detects the back electromotive voltage generated on a tracking actuator 4, and generates a tracking speed control signal so as to reduce the speed of the objective lens in the disk radial direction based on the detection result to output it to a first tracking switching means 20.
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