OPTICAL PICKUP DEVICE AND OPTICAL INFORMATION DEVICE

摘要

PROBLEM TO BE SOLVED: To prevent destruction of existing data when linear velocity of recording and playing back is switched in one and the same optical disk without making focusing servo unstable by an optical beam transmission adjusting means for adjusting optical power of the optical beam emitted from a light source.

SOLUTION: The optical beam transmission adjusting means 100 is constituted of a beam splitter 101, a liquid crystal element 102, and an optical beam transmission adjustment control circuit 103. The liquid crystal element 102 rotates a polarization direction of the optical beam made incident according to allied voltage. The optical beam transmission adjustment control circuit 103 outputs voltage while continuously varying a voltage value when output voltage is switched. Also, the circuit 103 attenuates a transmission rate continuously during recording or playing back operation for one and the same optical disk before linear velocity of the optical disk for an optical pickup device is switched from high linear velocity to low linear velocity in one and the same radius position.

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