Patent ID: 6399228
Filing Date: 2002-06-04
Classification: B05D,C03C,C09D,G02B

Abstract:
A multi layer interference device having a reflectance spectrum comprising at least one maximum comprising;at least one multilayer stack, a reflective layer having at least one surface for carrying said at least one multi layer stack, said at least one multi layer stack comprises a first layer of dielectric material, a layer of absorbing material and a second layer of dielectric material arranged in series with the layer of absorbing material situated between the first and second layers of dielectric material, wherein the second layer of dielectric material has substantially the same optical thickness as the first layer of dielectric material at a wavelength substantially corresponding to a maximum in the reflectance spectrum and wherein the layer of absorbing material has a refractive index n and an optical constant k, such that incident electromagnetic radiation, having a wavelength at which odd multiples of half wavelengths substantially correspond to the optical thickness of the at least one multi layer stack at said wavelength, is substantially absorbed within the device, wherein the layer of absorbing material is a conductive substoichiometric metal oxide and in that the device has a reflectance spectrum in the infrared wavelength region.