A multi layer interference coating comprising at least one multi layer stack deposited on a reflective layer, wherein each multi layer stack comprises a first dielectric layer, a layer of absorbing material and a second layer of dielectric material arranged in series and having a reflectance spectrum in the infrared region comprising at least one maximum. The dielectric layers are of equal optical thickness and typically are of the same material. The multi layer structure of the coating is such that incident electromagnetic radiation, for which odd multiples of half wavelengths correspond to the optical thickness of the multi layer coating at the incident wavelength, do not propagate within the coating and reflection at these wavelengths is suppressed. Coatings may therefore be designed to have a near saturated colour in the visible wavelength spectrum. The reflective layer may be a metal or a conducting oxide, a conducting nitride, a conducting silicide or a conducting sulphide. By using conducting oxides as absorbing layers the coatings may be designed to have strong reflectance characteristics in the infrared wavelength region and may also be designed to have temperature dependent reflectance characteristics. Substoichiometric metal oxides, such as TiOx may also be used as the absorbing material. IMAGE
展开▼
