| 摘要 |
PROBLEM TO BE SOLVED: To suppress the disturbance of tracking control even when a defective part such as a failure at an optical disk manufacturing stage is present in a recording surface. SOLUTION: An output terminal 2 is connected to an optical pickup 1 to output a prior subbeam return light signal obtained by converting a prior subbeam return light before a main beam into an electric signal. A defect period detection circuit 5 detects a defect period where a beam passes through the defective part of an optical disk 8 based on the prior subbeam return light signal from the output terminal 2. A servo hold circuit 7 holds tracking servo during the detected defect period. Thus, even when a steep attenuation occurs in the amplitude of an RF signal during the defect period, the defect period is detected at the early stage of the attenuation to suppress a change in the amplitude of a tracking signal. COPYRIGHT: (C)2006,JPO&NCIPI
|
