OPTICAL FILTERS FOR SUPPRESSING UNWANTED REFLECTIONS

摘要

An optical filter is provided for suppressing unwanted reflections of background light when used with a display device such as a cathode ray tube or an electroluminescent screen, or in optical communication or surveillance. The filter has multiple thin layers including a first series of layers for suppressing reflections from its outer surface and a second series of layers constituting a bandpass interference filter. The first series of layers is arranged to suppress reflections over a broad wavelength band while the second series of layers allows transmittance over a relatively narrow wavelength passband within the broad wavelength band, resulting in improved contrast when the display is used in situations of high background light.