| 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)] | 22 Claims |

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1. An optical waveguide display comprising:
a waveguide;
a source of light modulated with temporally-varying angularly-distributed information;
a fold grating of a first prescription configured as an evanescently coupled layer in proximity to the waveguide;
an input coupler for directing the light into total internal reflection (TIR) paths in a first propagation direction in the waveguide; and
an output grating for extracting the light from the waveguide,
wherein the fold grating provides a first beam expansion and diffracts light in the first propagation direction into a second propagation direction,
wherein the output grating provides a second beam expansion,
wherein light in a first TIR angular range in the first propagation direction undergoes at least two diffractions within the fold grating,
wherein each ray from the first angular range and its corresponding diffracted rays lie on a diffraction cone of the fold grating,
wherein each diffraction provides a unique TIR angular range along the second propagation direction.
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