Patent ID: 11796747

Abstract:
A diffractive optical waveguide is provided, which comprises a waveguide substrate and a coupling-in grating, a coupling-out grating, and a coupling-in end light-return grating formed on the substrate, the coupling-in grating couples an input beam into the waveguide substrate and forms a first beam of light propagating toward the coupling-out grating and a second beam of light not propagating toward the coupling-out grating, the coupling-out grating couples at least a part of the light propagating therein out of the substrate, and the coupling-in end light-return grating diffracts the second beam of light so that it propagates toward the coupling-out grating. A display device having the above diffractive optical waveguide is also disclosed. By providing the coupling-in end light-return grating, optical coupling efficiency of the diffractive optical waveguide is improved, and the energy distribution uniformity of an output field of the diffractive optical waveguide is improved.