Laser spot is irradiated to phase change die optical disk initialization manner and the phase change

摘要

PROBLEM TO BE SOLVED: To always perform a stable focus servo operation irrespective of a reflectance ratio of an initialized layer and that of an adjacent layer in initialization of a phase change-type optical disk having a plurality of recording layers.;SOLUTION: A second focus error signal whose phase of an S curve differs from that of a focus error signal used for a focus follow-up operation is disposed, and the signal is used for a focus gain control operation. Thus, the focus servo operation is performed in a state where reflected light from a layer except for the recording layer being a follow-up target is completely separated.;COPYRIGHT: (C)2004,JPO