A beam splitter having an optical multilayer thin film is disclosed. The optical multilayer thin film is formed by laminating six layers in sequence. The laminated six layers comprise: a first layer, a third layer and a fifth layer each having a refractive index from 1.63 to 1.64; a second layer and...http://www.google.fr/patents/US5579159?utm_source=gb-gplus-shareBrevet US5579159 - Optical multilayer thin film and beam splitter
