| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical path switching element which is simple in structure, is high in durability, can be reduced in a member cost and is high in the degree of freedom in device design. SOLUTION: This optical path switching element has a light incident section 103 across a light guide member 101, a reflection section 115 which reflects incident light 1 entering therefrom and a light exit section 104 which takes the reflected light thereof as the exit light to the outside through the light guide member 101. A refractive index variable material 105 is sealed into the optical path on the reflection section 115 side and the element is provided with signal input means for applying a signal to the refractive index variable material 105 and giving rise to a change in the refractive index within a range where the incident light 1 is not totally reflected at the boundary between the light guide member 101 and the refractive index variable material 105. The angle ϕ formed by the normal to the surface constituting the light exit section 104 and the optical axis of the incident light 1 transmitted through the inside of the light guide member 101 is so set as to be made smaller than the incident angle θ1 on the light incident section 103. Namely, the angle described above is so set that the exit point of the exit light in the light exit section 104 exists on the exit point side of the incident light 1 in the light incident section 103. |
