| 摘要 |
Since the devices used hitherto, operating with temperature sensors, for detecting the formation of ice and/or hoar frost occasionally signal the formation of ice or hoar frost at negative temperatures although the former are not yet actually present, or indicate no icing although it has already occurred at positive temperatures, the invention provides a device which despite a relatively simple design always reliably detects and quantitatively measures formation of ice or hoar frost. The device consists of a light source (3) which directs a beam of polarised light onto the surface (1) of a body (2) coated with a layer (S) of ice or hoar frost. The reflected light passes to a light-receiving device (13), and if the polarised light is depolarised by the layer (S) of ice or hoar frost it passes through a single-tuned filter (23) onto a photodiode (24), so that, for example, a threshold-value detector (26) emits a signal characteristic of the formation of ice or hoar frost. <IMAGE>
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