Patent ID: 8000020

Claim:
An optical system comprising: a first light-transmitting substrate having at least one major surface and edges; a display light source; a coupling optical element carried by said substrate, such that light waves from said display source are coupled by said coupling optical element into said substrate by total internal reflection; at least one polarizing beam-splitter carried by said substrate, at least one reflecting optical element, and at least one retardation plate; wherein said retardation plate is located between at least a portion of the major surface of the substrate and said reflecting optical element and wherein said polarizing beam-splitter reflects light waves which are coupled inside the substrate into said reflecting optical element; a second light-transmitting substrate having at least two major surfaces parallel to each other and two edges; a second optical element for coupling light into said substrate by internal reflection; and at least one partially reflecting surface located in said substrate, which surface is non-parallel to the major surfaces of said second substrate, wherein said second substrate is positioned adjacent to said first substrate.