| 摘要 |
PURPOSE:To obtain a compact optical head by forming approximately U-shaped optical path for the laser light reaching an objective lens from a semiconductor laser and leading the laser light to the objective lens from the semiconductor laser which are set at the same side. CONSTITUTION:The laser light radiated from a semiconductor laser 11 is refracted via a triangular prism 15 and sent back in the direction parallel and opposite to the radiating direction of the laser 11 to reach an objective lens 18 via a 45 deg. mirror 16. Thus the laser light radiated from the laser 11 is led to the lens 18 along an approximately U-shaped optical path and focused via the lens 18 to be projected on a disk D. The light returned from the disk D travels straight a half mirror 14 and a signal detecting optical system 20 is set on an optobase 10 set at the back side of the mirror 14. Thus the length of an optical head main body is reduced down to about 1/2 optical path set between the laser 11 and the lens 18. Then a compact optical head is obtained. |
