US Patent 7949214 Substrate guided relay with pupil expanding input coupler

An optical substrate guided relay (300) includes an optical substrate (302) having at least one major face (411), an output coupler (303) coupled to a major face (411,412), and an input coupler (301) coupled to a major face (411,412). The input coupler (301) is configured to reflect, via internal layers (414), portions of received light to the optical substrate 302. The input coupler (301) includes either one or more internal layers (414) or a contoured face (1040) with surfaces configured as reflectors that expand the received light and direct it into the optical substrate (302). The output coupler (303) expands a pupil of light in one direction and directs the expanded light away from the optical substrate guided relay.