| 摘要 |
PROBLEM TO BE SOLVED: To solve the following problem: in a high multilayer disc composed of many recording layers with small gaps, signal interval of a focus error signal (FE signal) detected in each recording layer becomes small, so that signal interference occurs and undesired offset or the like is generated, thereby significantly degrading quality of the FE signal. SOLUTION: The mutual interference between FE signals is remarkably reduced by arranging a new detection surface at a position adjacent to a conventional FE signal detection surface, and by multiplying a predetermined detection signal obtained from the detection surface by a predetermined coefficient value decided in accordance with recording layer spacing, and subtracting the detection signal from the original FE signal. COPYRIGHT: (C)2010,JPO&INPIT |
