| 摘要 |
PURPOSE:To secure the proper operation of a windshield wiper by accurately detecting a raindrop at the time of a rainfall, by inclining a pair of electrodes of and down in the longitudinal directions thereof and forming a groove along the longitudinal direction of each electrode. CONSTITUTION:The upper surface of an insulating substrate 20 is inclined so that a pair of electrodes 30, 40 are inclined up and down along the longitudinal directions thereof and a groove 22 is formed to the upper surface of the insulating substrate 20 between a pair of the electrodes 30, 40 along the longitudinal directions of both electrodes. Each of the width and depth of the groove 22 is made almost equal to the average diameter of a raindrop estimated at the time of a rainfall. By this constitution, even if each raindrop is adhered to the electrodes at the time of a rainfall, said raindrop is fallen in the groove 22 to smoothly flow downwardly along the groove 22 without protruding above the electrodes 30, 40. Therefore, even if the surfaces of the electrodes are contaminated with dust or mud, no water film is formed over the electrodes and the raindrop can be detected certainly.
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