Patent ID: 7351949

Claim:
A switch panel comprising: a touch plate comprising an optically transparent layer having first and second surfaces, said optically transparent layer having an index of refraction greater than that of air, said touch plate conducting light of an excitation wavelength between said first and second surfaces and emitting part of said light through said second surface at one of a plurality of emission locations determined by pressure being applied to said first surface at a corresponding location; a light converter positioned to receive said light emitted through said second surface at each of said plurality of emission locations, said light converter generating light having a plurality of distinct location-specific spectra, one of said location-specific spectra corresponding to each of said emission locations, said one of said location-specific spectra being determined by said emission location, said light converter comprising a layer of phosphor on a third surface, said layer of phosphor having a composition that is a function of position on said third surface; and a light analyzer that generates a signal indicative of which of said location-specific spectra was generated by said light converter.