| 摘要 |
A liquid drop detector which may be fixed or attached by a simple operation, without machining, to a window glass, comprising: a light emitting element 4, a light receiving element 5, and light guiding bodies 7, 8 and 9, wherein the light emitted by the light emitting element 4 is introduced through a diffraction grating 15 into the light guiding body 7, and after undergoing total internal reflection within the light guiding body 7, it is introduced through a silicon member 10, the light guiding body 9 and a silicon member 10 into a windshield G. After repeating total internal reflection within the windshield G, the light is received by the light receiving element 5 through the silicon member 10, the light guiding body 9, the silicon member 10 and the light guiding body 8. In this instance, when rain drops adhere to the outside surface of the windshield G at points corresponding to the total internal reflection points at the outer surface of windshield G, the light reflecting within the windshield G passes out of the windshield G at that point without undergoing the total internal reflection therein. As a result of this, the amount of light received by the light receiving element 5 is lessened, thereby providing for detection of the adhesion of rain drops based thereupon so as to output a signal for driving a device such as the wiper. <IMAGE> |
