| 摘要 |
PURPOSE:To easily adjust the returned light quantity to a semiconductor laser by providing a means returning a part of a laser light emitted from a light source to the light source between the light source and a light splitter. CONSTITUTION:The light emitted from the semiconductor laser 6 transmits the beam splitter (BS) 8 and is reflected therein via a collimater lens 5. The light transmitted through the BS 8 forms a minute spot on an optical recording medium 1 via the BS 4, a lambda/4 plate 3 and an objective lens 2. The reflected light goes reversely and is reflected in the BS 4 and made incident on the photodetector 7. On the other hand, the light reflected in the BS 8 is reflected in the mirror 9 and the returned light quantity is adjusted by a light shielding plate 10 and is reflected in the BS 8 and returns to the semiconductor laser 6. |
