| 摘要 |
For the automatic control of the wiper on the windscreens and/or rear windows of motor vehicles, a rain sensor is proposed whose mode of operation is based on the evaluation of the transmission properties of a high-frequency, electromagnetic surface wave which is conducted by the glass pane in the region of the wiper 5, the said transmission properties being changed by dispersion elements (here water droplets). The surface wave is emitted directed by a transmitting aerial 2 which is attached to the inside of the glass pane 1 and is received by a receiving aerial 3. Wetting of the glass pane by rain causes the surface wave to be damped which is detected in the electronic control and evaluation circuit 4 and used to switch on the wiper motor 6. After the wiping process, the surface wave propagates again in an undisturbed fashion. <IMAGE>
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