| 摘要 |
PURPOSE:To improve the operability and to simplify the structure by providing optical path switching elements which have reflecting surfaces for switching the directions of light beams guided though respective optical paths selectively between straight directions and right-angled directions and an optical attenuation member which attenuates the quantity of light. CONSTITUTION:The respective optical paths of 1st optical path groups 1a and 1b, and 2a and 2b and the optical paths of 2nd optical path groups 3a and 3b cross each other at right angles. Then optical path switching elements 21a - 21d are arranged at respective intersections. The optical path switching elements 21a - 21d switch the directions of light beams guided through the respective optical paths selectively between the straight directions and right- angled directions. Further, an optical path switching element which is specified previously is provided with the optical attenuation member 23 which attenuates the quantity of light reflected by the reflecting surfaces 22, so only the light which travels through the optical path switched by an optical path switching element to the right-angle direction is attenuated. Consequently, the operability, economy, and reliability are improved. |
