| 摘要 |
PCT No. PCT/CH93/00160 Sec. 371 Date Feb. 16, 1994 Sec. 102(e) Date Feb. 16, 1994 PCT Filed Jun. 22, 1993 PCT Pub. No. WO94/00319 PCT Pub. Date Jan. 6, 1994.An automatically controlled cleaning device (14) for removing visibility-impairing foreign matter, e.g. rain, snow or mud, from the surface of a window such as a motor vehicle windscreen (8). The device uses a sensor such as an ultrasonic transducer (12a, 12b) in which the frequency (f) and the spacing (d) between the transmitter (12a) and the receiver (12b) enable the presence of foreign matter to be detected simply by measuring the phase difference between the transmitted signal and the received signal. This device may be used in automatic wiper systems or the like. |
