| 摘要 |
PROBLEM TO BE SOLVED: To prevent deterioration of jitter of reproducing signal and deterioration of reliability of light quantity control of semiconductor laser when the laser spots are made fine by opodization. SOLUTION: A shielding zone 4 is placed between a semiconductor laser 1 and a collimating lens 2 converging the laser beam which is the diverging beam exitted from the semiconductor laser 1 into parallel beam. The shielding zone 4 modifys pupil function so that only a central part of incident laser beam is shielded. After that, polarized beam splitter 5 is arranged to execute separation of optical path so that the reflection beam is not sheilded by the shielding zone 4. |
