| 摘要 |
PROBLEM TO BE SOLVED: To provide a focus control method of an optical disk device capable of recording and reproducing unaffected by an external factor, such as a temperature change, and the optical disk device thereof. SOLUTION: In the control method, recording is performed in positions of at least three points including; a position of an objective lens 5 that follows the focus by determining it to be the optimal focus; a position displaced by a specified distance to the side of the optical disk 1 with respect to the position of the objective lens 5 that follows the focus by determining it to be the optimal focus; and a position displaced by a specified distance to a direction opposite to the side of the optical disk 1 with respect to the position of the objective lens 5 that follows the focus by determining it to be the optimal focus. The results of the measurements of the amplitude of an RF signal measured in the position of the at least the three points are compared, and thereby the amount of an offset with respect to the focus error signal is determined and the offset signal having such amount of the offset is added to he focus error signal. COPYRIGHT: (C)2007,JPO&INPIT
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