| 摘要 |
PURPOSE:To detect waterdrops adhered to the surface of a glass at a high sensitivity by such an arrangement wherein light rays radiated from a luminous device which are being propagated through the interior of a transparent plate are guided into plural photoelectric conversion elements through a photoconductive wave path, and the detected outputs of these elements are taken out as time serial signals. CONSTITUTION:A luminous device 30 composed of a luminous element 31 and a drive circuit 32 causes pulse-like photosignals to enter a glass plate 10 through a photoconductive wave path 40 at the incidence side. These light rays propagate through the glass plate 10 by repeating total reflection and enter a photosensor 33 in which plural photoelectric conversion elements 33a-33n are arranged in a row through a photoconductive wave path 41 at the radiation side. The output of each photoelectric conversion element is read out by a multiplexer 34 as a time serial signal, and applied to a detection circuit 37 through an amplifier 35 and a band-pass filter 36. If waterdrops adhere to the glass plate 10, the energy density of light rays entering photoelectric conversion elements is varied by each element and this variation of density can be detected by a decision circuit 38. |
