| 摘要 |
PURPOSE:To enable photodetection and focusing for a long time in spite of the change in the incident angle of the solar light and to reduce the size of a device, by superposing a suitable number of transparent discs on the bottom surface of a planoconvex lens and constituting a convex face on the bottom surface of the lowermost transparent disc. CONSTITUTION:A suitable number of transparent discs (b) are superposed on the bottom surface of a planoconvex lens a of a flat bottom surface constituting a photodetecting lens 1, and a concave face (c) is provided on the bottom surface of the transparent disc b' in the lowermost part. The focus (f) of the solar light at 45 deg. incident angle is focused to the extremely near position around the optical axis line Z by the effect of the concave face (c). The lens 1 is exposed and held by a holder 2, and concave face parts 4a, 4b are formed on the top and bottom surfaces of a short circular columnar medium 4 made of glass in a circular conical cylinder body 3. Further a photoconductive cable 6 is connected to the lens. With such constitution, the long-term photodetection and focusing of the solar light is made possible, and the need for a device which moves the lens in conformity with the movement of the sun is eliminated. |
