Dew point sensor for car windscreen demister and food storage control has substrate with flexible membrane over thin flat cavity with small opening using interference color change due to dew

摘要

A dew point sensor (10) has a substrate (13) with Peltier element (15) or resistance heater temperature control and thin flat cavity (11) on the inner side of an insulated (14) flexible membrane (12) with a small opening (19) to the environment above the surface (20) and dimensions such that flexing of the membrane to fill the cavity produces an observable change in interference color. Includes Independent claims for a sensor system using several sensors and for the use of capacitance sensing to detect dew.