Substrate-guide optical device utilizing polarization beam splitters

An optical device, comprising:

• a light waves-transmitting substrate having at least two major surfaces and edges;
• optical means for coupling light waves into the substrate by total internal reflection;
• a plurality of partially reflecting surfaces located at a distance from each other and carried internally within the substrate, wherein the partially reflecting surfaces are parallel to each other and located at an angle to the major surfaces of the substrate,
• at least two of the partially reflecting surfaces being anisotropic, each anisotropic surface having a major axis, the anisotropic surfaces being mounted with the major axis in different directions, wherein light waves coupled into the substrate pass through at least one of the partially reflecting surfaces, at least two times at two different incident points, and in two different incident directions,
• the polarization of the light waves at the first incident point in a first direction is substantially different than the polarization of light waves at the second incident point in a second direction, the coupled light waves being partially reflected out of the substrate by the partially reflecting surfaces.