| 摘要 |
A focus control is performed on the basis of a focus error signal indicative of a deviation amount from a focus state in a recording layer of a laser beam emitted for reproducing information to an optical disk having a plurality of recording layers. Specifically, at the time of focus-jumping a laser beam from a recording layer to another recording layer, an acceleration pulse or a deceleration pulse as a brake signal for making a focus jump is applied to a focus drive signal for controlling driving of an optical pickup for emitting a laser beam. The timing of applying each of the brake signals is variably set on the basis of the level of a focus error signal of a recording layer as an object of the focus jump. As a result, the focus jump can be accurately made in accordance with variations in the level of the focus error signal caused by variations in transmittance of light according to materials of the recording layers.
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