| 摘要 |
PURPOSE:To actuate a wiper by detecting the amplitude modulation of the signal of a rain drop sensor and automatically control the lights by detecting the background level. CONSTITUTION:A light-receiving 5 and a light emitting diode 1 are provided on one surface of a transparent plate 2 so that the light from the light emitting diode 1 is reflected in the transparent (glass plate) 2 and is made to reach the photodiode 5. A wiper blade 19A is provided on the other surface of this transparent plate 2 and a preset frequency signal is applied to the light emitting diode 1 through an oscillator circuit 10 and then the amplitude modulation of an electric signal that appears in the light-receiving 5 is detected by a detector circuit 15. When the output signal of this detector circuit 15 exceeds a preset threshold level, a signal is issued from the first control circuit 18 to drive a wiper motor 19. Besides, when the electric signal for the background illumination that appears in the light-receiving diode 1 exceeds a preset threshold level, a signal is issued from the second control circuit 22 to close a switching circuit 23 and the switches of lights 24 and then turn on the lights 24. |
