Patent ID: 8023065

Claim:
An optical system, comprising: an image-forming panel having an illumination side and a viewing side; a light guide disposed to the illumination side of the image-forming panel; and an illumination light unit, where the light guide is optically between the illumination light unit and the image-forming panel, the illumination light unit comprising one or more light sources capable of generating illumination light and a controlled transmission mirror arranged to receive the illumination light from the one or more light sources, the controlled transmission mirror comprising an input coupling element comprising at least one of a bulk diffuser, a surface diffuser or a structured surface, an output coupling element comprising at least one of a bulk diffuser, a surface diffuser or a structured surface, and a first multilayer reflector disposed between the input and output coupling elements, the first multilayer reflector having a bandedge defined by angle θ min , wherein the input coupling element diverts at least some of the illumination light incident thereon at an angle less than θ min into an angle greater than θ min so that the diverted light is transmitted through the multilayer reflector to the output coupling element, and further wherein illumination light from the output coupling element is coupled into the light guide.