| 摘要 |
PURPOSE:To scale down the layout of an optical system by arranging the light receiving end surfaces of a first light receiving element and a second light receiving element and the light emitting and surface of an laser light source close to each other so as to be parallel with each other. CONSTITUTION:A separate prism 17 which is formed by integrating a semitransmissive layer 18, a polarizing film 19 and a total reflecting plane 20 into one body and is used concurrently as a light emitting optical system and a detecting optical system is provided. This prism 17 is fitted to a supporting stand 21 installed on a base 15, and a trisected light receiving element 22 as the first light receiving element is arranged on one surface of the supporting stand 21 positioned on the optical path of light reflected by the polarizing film 19, and besides, the trisected light receiving element 23 as the second light receiving element is arranged on one surface of the supporting stand 21 positioned on the optical path of the light reflected by the total reflecting plane 20. In this case, the light receiving end surfaces of the light receiving elements 22 and 23 and the light emitting end surface of the laser light source 16 are arranged close to each other so as to be parallel with each other. Thus, the layout of the optical system can be scaled down. |
