Optical switching device e.g. touch switch for operating ceramic hotplate etc., has cover comprising e.g. non-metallic polymer film which is reflective in visible wavelength range

摘要

The optical switching device has a cover (10) that is transmissive to electromagnetic radiation in a predetermined wavelength range. A radiation source (18a,20a) and a sensor (18b,20b) are arranged on a side of the device facing away from the user. The cover includes a film (24) that is reflective in the visible wavelength range, and at least partially transmissive in the non-visible wavelength range of the electromagnetic radiation. The film is preferably formed from a multilayer non-metallic polymer film.