Optical system with compact coupling from a projector into a waveguide

An optical system comprising:

• (a) a light-guide optical element (LOE) formed from transparent material and having mutually-parallel first and second major external surfaces for guiding light by internal reflection;
• (b) a projector configured to project light corresponding to a collimated image from an aperture, the light exiting said aperture with a chief ray defining an optical axis of said projector and with an angular field about the chief ray;
• (c) a coupling-in arrangement associated with said projector and with said LOE for coupling said light from said projector into said LOE at a coupling-in region so that the light undergoes internal reflection at said major external surfaces, said coupling-in arrangement including a reflective polarizing beam splitter and a waveplate deployed such that, for at least one part of said angular field, the light propagating within said LOE has spatial non-uniformity of polarization;
• (d) a coupling-out arrangement associated with said LOE for redirecting the light propagating within said LOE towards a viewer, said coupling-out arrangement being polarization-sensitive;
• and
• (e) a non-uniformity mitigating element selected from the group consisting of:
• a retarder;
• a birefringent depolarizing element;
• and a partially-reflecting mixing element, said non-uniformity mitigating element being associated with said LOE and deployed to interact with the light propagating within said LOE between said coupling-in arrangement and said coupling-out arrangement to as to decrease a non-uniformity in the light redirected towards the viewer caused by said spatial non-uniformity of polarization.