| 摘要 |
PURPOSE:To improve the light introducing efficiency and to reduce the diameter of a photoconductor cable by using a Fresnel lens whose numerical aperture is smaller than that of the optical conductor cable and adhering the light emission end of a coupling and the light reception end of the cable. CONSTITUTION:An optical coupling 3 is used whose area on the side of a light reception end 3a is large and area on the side of an output end 3b is small, and a relatively large image of the sun converged by a Fresnel lens having a relatively small numerical aperture is received by the wide area 3a of the coupling 3 and is introduced. This introduced light is repeatedly reflected on a peripheral surface 3c and is emitted from the output end 3b with an angular aperture approximately equal to the numerical aperture of a photoconductor table 2. Consequently, the reflection loss on the light reception and face of the cable is eliminated. |
