| 摘要 |
PURPOSE:To condense the light incident at specific angles efficiently with simple constitution by using the small-diameter end of a reflection mirror of circular conical cylinder shape as a photodetecting window, providing a spherical mirror or condenser lens at the large-diameter end and disposing a photodetector at the focus thereof. CONSTITUTION:A spherical mirror 9 or a condenser lens 10 is provided at the large-diameter end of a reflection mirror 8 of a circular conical cylinder shape, and a photodetector 6 is disposed at the focus thereof. If the angle of the reflection mirror 8 to the centerline is defined as theta, the direct light (a) entering in parallel to the central axis and the light (b) entering at an angle of 2theta out of the incident light, for which the photodetecting window 2 is the small-diameter end, enter the photodetector 6. Thereby, the light entering stereoscopically in the front direction and at the specific set angle (2theta) are condensed efficiently with the simple constitution. |
