| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect a quantity of emitting light of a laser light source. SOLUTION: This laser light projecting device 1 is capable of reading and writing information on an optical disk, having the laser light source 2, a diffraction grating 3, a polarizing beam splitter 4, a collimator lens 5, a photodetector 6, a screw member(light shielding member) 7 and a control system 8. The control system 8 is composed of a driver 82 for driving the laser light source 2. The screw member is installed on the side of a light receiving surface 61 of the photodetector 6, and the laser light 18 outside an effective optical path area 16 to irradiate the light receiving surface 61 of the photodetector 6 is partially intercepted by a protruded tip part 72 of this screw member 7. A protruding amt. of the tip part 72 is adjusted by a turning direction and a turning amt. of the screw member 7, and an irradiated area of the light receiving surface 61 to be irradiated with the laser light 18 can thus be adjusted. |
