| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical disk drive device in which accurate focus jump is performed, a focus control device, and a focus control method. SOLUTION: When focus jump of a laser beam is performed from one recording layer to the other recording layer based on a focus error signal FE indicating deviation quantity from a focus state in a recording layer of a laser beam emitted to an optical disk having a plurality of recording layer to reproduce information, an acceleration pulse and a deceleration pulse being a braking signal for focus jumping are applied to a focus drive signal FD controlling drive of the optical pickup emitting a laser beam (S4, S10). Since applying timing of these control signals is variably set based on a level of the focus error signal FE of the recording layer being an object of focus jump (S3, S7, S9). focus jump is performed accurately in accordance with dispersion of levels of focus error signals FE caused by dispersion of transmissivity of light by materials of each recording layer. COPYRIGHT: (C)2004,JPO
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