Faceted coupling-in element to a waveguide

Abstract

A conjugate coupler for coupling image light into a waveguide of a near-eye display comprises a coupling block having multiple facets oriented at conjugate elevation angles relative to a coupling-in mirror. The facets split incoming light rays into complementary ray sets, with at least one partially reflective surface reflecting a first portion and transmitting a second portion of the light. The conjugate coupler generates complementary ray sets that compensate for aperture-filling deficiencies by directing split light rays at varying incidence angles toward the coupling-in mirror, thereby improving illumination uniformity across the waveguide aperture. The first ray set impinges the coupling-in mirror at higher incidence angles than the second ray set, filling aperture regions that would otherwise be unilluminated and enhancing image quality at the eye box of the display.

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