| 摘要 |
<P>PROBLEM TO BE SOLVED: To perform light source emitting power control and various servo controls or the like with higher accuracy. <P>SOLUTION: Information is recorded on an optical disk DSC by a laser beam Po emitted from a semiconductor laser LD. When sample-and-holding a detection signal Sapc presenting the power of the laser beam outputted from a photodetector PD by a sample-hold circuit 4 via a current-voltage converter 3, the detection signal is sample-held at a delayed timing corresponding to the delay time of the current-voltage converter 3. Moreover, based on the a detection signal Sft having the information on a tracking error and a focus error outputted from a photodetector OEIC, the sample-and-hold circuits 8, 9 sample-hold a tracking error signal Ste and a focus error signal Sfe generated by a tracking error generation circuit 6 and a focus error generation circuit 7, respectively, at delayed timings corresponding to the delay times of respective generation circuits 6, 7. Then, power control, tracking servo and focus servo controls are carried out according to each of the signals Vsh, TE, FE held by the sample-and-hold circuits 4, 8, 9. <P>COPYRIGHT: (C)2004,JPO |
