| 摘要 |
PROBLEM TO BE SOLVED: To improve reliability of interlayer jump by determining whether a signal is a false signal generated by a noise, stray light or interference of adjacent layer, etc., or is a true FE signal, in an optical disk having a plurality of recording layers. SOLUTION: The disk apparatus includes a focus error signal creating section obtained by a photodetector, a pull-in error signal creating section for creating a summation signal, and a focus control section for controlling so that a focal point of the laser beam is moved from one information surface of the optical disk to other information surfaces in accordance with the focus error signal. The focus control section detects whether the laser beam is being focused to the information surface, on the basis of inclinations of the focus error signal and the pull-in error signal. COPYRIGHT: (C)2010,JPO&INPIT |
