| 摘要 |
PROBLEM TO BE SOLVED: To downsize a hologram laser unit without adding an element to bend the optical axis of a mirror, etc. SOLUTION: The optical axis of the semiconductor laser element 3 and the photodetecting surface of a photodetector 4 for signal detection are arranged in parallel and the signal light returning from a disk is diffracted by a hologram element 8 arranged perpendicularly to the optical axis. The photodetecting surface of the photodetector 4 for signal detection is irradiated with this light. The distance between the optical axis of the laser and the photodetecting surface of the photodetector may be regulated by the thickness of a sub-mount 20 which is arranged on the photodetecting surface and is mounted with the semiconductor laser element 3. The wiring from the hologram laser to the outside may be led out from one point by drawing about a pattern on the photodetector. |
