A polarized light extraction optical element is formed by a light-transmitting base material and a polarization separation layer laminated thereonto, this polarization separation layer being a liquid crystal layer made of a cholesteric liquid crystal. The thickness of the liquid crystal layer is smaller...http://www.google.com.au/patents/US20020113923?utm_source=gb-gplus-sharePatent US20020113923 - Polarized light extraction optical element
