| 摘要 |
PROBLEM TO BE SOLVED: To provide a raindrop sensor, in which the shape of a prism is contrived and in which a light-emitting element and a light-receiving element are arranged to the side of the center from both ends of the prism, while the expansion of the detection region of a raindrop is being ensured. SOLUTION: An incident-side prism wall 20b of the prism 20 refracts light from the light-emitting element 40 by a cross-sectional convex lens face 26, the light is changed into a parallel light, and the parallel light is reflected toward the inner surface of a front windshield W by a paraboloid-shaped outer face 28. The parallel light, reflected by the inner surface of the front windshield W, is reflected by a paraboloid-shaped outer face 29, so as to be condensed on a radiant-side prism wall 20c by the element 50 by a cross-sectional convex lens face 27. The cross-sectional convex shapes of the respective lens faces 26, 27 are formed into an arc shape, while the element 40 and the element 50 are used as the center.
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