US Patent 8432614 Substrate-guide optical device utilizing polarization beam splitters

An optical device including a light waves-transmitting substrate having two major surfaces and edges, has optical means for coupling light into the substrate by total internal reflection, and a plurality of partially reflecting surfaces (22a, 22b) carried by the substrate. The partially reflecting surfaces (22a, 22b) are parallel to each other and are not parallel to any of the edges of the substrate. One or more of the partially reflecting surfaces (22a, 22b) is an anisotropic surface.