| 摘要 |
PURPOSE:To make a photodetector compact to improve the visibility of driving, by interposing an aspherical cylinder lens between a slit plate of the photodetector and a photodetecting element. CONSTITUTION:The light from a projector 8 on the outside of a vehicle is made incident into a photodetector 1 through a window glass 13 and an infrared transmission filter 3 of the photodetector 1, and the incident light is led to a photodetecting element 5, which are provided in the depth, through a slit plate 4 and an aspherical cylinder lens 6. A control circuit 15 is operated by a light reception signal to determine operation speed and period of a wiper blade 17. Since the aspherical cylinder lens 6 is interposed between the slit plate 4 and the photodetecting element 5 to constitute this photodetector 1, the sensitivity of photodetection of the photodetector 1 is enhanced sufficiently, and the photodetector 1 is made compact; and since no extremely projecting parts are formed with respect to design, the visibility of driving is not hindered. |
