Projection optical system for coupling image light to a near-eye display

A near-eye display device comprising:

• a near-eye support structure;
• a near-eye display (NED) supported by the near-eye support structure, the near-eye display including a waveguide;
• a projection light engine, including an image source and a projection optical system, supported by the near-eye support structure and having an external exit pupil which is external to the projection light engine;
• the projection optical system comprising a high index glass region in which a birdbath optical element with a reflective surface is immersed, the birdbath optical element collimates and reflects image light from the image source to the external exit pupil;
• and
• the near-eye support structure positions the waveguide for optically coupling the image light of the external exit pupil.

A method for coupling image light from an image source of a projection light engine to a near-eye display comprising:

• optically directing image light from the image source along a first optical path in a high index glass region within a projection optical system housing to a birdbath reflective optical element in the high index glass region;
• collimating and reflecting the image light by the birdbath reflective optical element along a second optical path extending through the high index glass region to an external exit pupil outside the projection optical system housing;
• polarizing the image light in at least one of the first optical path and the second optical path;
• and
• an input grating of a waveguide of the near-eye display optically coupling at least the image light of the exit pupil into the waveguide.