SELECTIVE INTERFERENCE LIGHT FILTER

摘要

SELECTIVE INTERFERENCE LIGHT FILTER A b s t r a c t The light filter has a layer structure wherein layers reflect directional luminous radiation and are equidistant with the refractive index varying periodically in depth. The layers are formed by exposing to monochromatic radiation at a predetermined wavelength an element made of a light-sensitive material transparent to said radiation and placed in front of a mirror only during the emission of radiation. In an optical instrument a selective element may be said light filter installed in a manner allowing its turn relative to luminous radiation directed thereto.