| 摘要 |
PROBLEM TO BE SOLVED: To correctly detect a tracking error signal regardless of kinds of disks. SOLUTION: The laser beam emitted from a laser coupler 31 passes through a grating 32, is made incident on a beam splitter 33, then reflected on it, and converged on a disk 50 by an objective lens 34. A reflected light from the disk 50 is guided to the beam splitter 33 by the objective lens 34, bisected by the splitter and the beam of one side passes through the grating 32 to be made incident on the laser coupler 31 and the other is made incident on a PDIC 35 (photodiode IC). The reflected light made incident on the coupler 31 is guided to a PDIC being in the inside of the coupler and a focus error signal is taken out from the PDIC by a differential spot size method. Moreover, a tracking error signal and a reproduced signal are taken out from the PDIC 35 by a three-beam method. Then, the whole of the laser coupler, the grating, the beam splitter and the PDIC or the like are integrated in an integration module 80. |
