| 摘要 |
PURPOSE:To secure the operation of a controller for wipers of a motorcar, and to facilitate its manufacture by arranging a light emitting element and a photodetecting element and using a frequency signal, and thus allowing the photodetecting element to generate an amplitude-modulated signal which corresponds to the amount of drops of liquid. CONSTITUTION:As raindrops stick to glass 2 and increase in amount, an amplitude-modulated signal appearing at the output of a detector 15 increases in amplitude and when it exceeds the fixed threshold value of a comparator 16, a wiper motor 19 is started by the output of a one-shot circuit 17 to sweep wiper blades 19A once. Once the other surface of glass 2 having a light emitting element 1 and a photodetecting element 5 embedded is swept with the blades 19A, the raindrops are removed and the amplitude-modulated signal decreases in amplitude. Then as the amount of raindrops increases, the motor 19 is started again. Thus, the blades 19A sweep the glass 2 at intervals of time which correspond to the amount of raindrops. |
