| CPC G02B 27/0101 (2013.01) [G02B 6/0036 (2013.01); G02B 2027/0118 (2013.01)] | 23 Claims |
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1. A waveguide display comprising:
a source of image modulated light;
a waveguide having an eye-facing surface and an external surface facing the outside world;
an input coupler for coupling the light into a total reflection internal path in the waveguide;
at least one grating for providing beam expansion and extracting light from the waveguide towards an eyebox;
a surface relief reflection grating comprising a modulation depth and a grating pitch, wherein the modulation depth is greater than the grating pitch across at least a portion of the polymer grating structure, wherein the surface relief reflection grating is positioned on the external surface of the waveguide,
wherein the surface relief reflection grating is configured to redirect stray light generated within the waveguide away from optical paths that are refracted through the external surface into the outside world and back out of the waveguide through the eye-facing surface,
wherein the surface relief reflection grating does not disturb the propagation of image modulated light within the waveguide and the extraction of the image modulated light towards the eyebox,
wherein the stray light generated within the waveguide comprises at least one selected from the group consisting of: light scattered from the grating material; zero order diffracted image modulated light; and image modulated light propagating along optical paths that are not extracted from the waveguide towards the eyebox.
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