CPC G02B 6/34 (2013.01) [G02B 5/1819 (2013.01); G02B 5/1823 (2013.01); G02B 5/32 (2013.01); G02B 6/0016 (2013.01); G02B 6/124 (2013.01); G02B 27/0172 (2013.01); G02B 27/4205 (2013.01); G02B 27/4261 (2013.01); G02F 1/13342 (2013.01); G02B 2027/0125 (2013.01)] | 20 Claims |
1. An optical waveguide display comprising:
a waveguide;
a source of light;
an input coupler for directing the light into total internal reflection (TIR) paths in a first propagation direction in the waveguide;
a first grating configured to diffract an incident light ray coupled into the waveguide as a diffracted ray in a first angular range at least twice and deflect the diffracted ray into a second propagation direction, wherein the first grating diffraction provides a unique diffraction efficiency versus angle characteristic along the second propagation direction; and
a second grating configured to diffract the incident light ray coupled into said waveguide as a diffracted ray in a second angular range at least twice and deflect the diffracted ray into a third propagation direction, wherein the second grating diffraction provides a unique diffraction efficiency versus angle characteristic along the third propagation direction,
wherein in each of the first grating and second grating, the diffracted ray and the corresponding incident ray lie on a diffraction cone of the first grating or the second grating, and
wherein the first grating and second grating provide beam expansion and extraction of light from the waveguide.
|