FOCUS-POSITIONING METHOD AND RECORD/REPRODUCING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a focus-positioning method that allows to obtain a land track and a groove track, and successful record/reproducing characteristics. SOLUTION: A focus-positioning coarse surveying section 50 and a focus-positioning position precision inquiry section 60 distinguish whether a light beam spot is positioned in the land track or the groove track and probes the new two (for land and groove) of focus positioning that makes the envelope and the jitter of a bit error rate BER and a regenerative signal RF measured by an error rate measure part 33, based on a land groove detecting part 34 and L/G switching signal LGS. Moreover, two control signals (FBAL and FOFF) for the change of a control target are output, to a focus error detecting part 36. COPYRIGHT: (C)2005,JPO&NCIPI