Icing risk indicator for vehicles - uses multiple film containing liq. crystals, stuck on windscreen, giving colour change under one degree centigrade

摘要

The vehicle frost indicator consists of a multiple film enclosing liquid crystals, for example cholesterics. The liquid crystals give instantaneous display of the temperature by light emission in the visible spectrum range. The film is stuck directly onto the windscreen or the surface of the exterior rear view mirror. Whatever the interior temperature of the vehicle, the thermal resistance of the windscreen is sufficient to ensure that the film is in equilibrium with the exterior air as soon as the vehicle moves. The liquid crystals are arranged to display a lette for example F for frost or I for ice and will take a determine spectral colour for an exterior temperature less then +1 deg.C.