Meta Platforms, Inc.
SLANTED SURFACE RELIEF GRATING FOR RAINBOW REDUCTION IN WAVEGUIDE DISPLAY

Abstract:

A waveguide display includes a substrate having two opposite surfaces, and a slanted grating at a first surface of the two opposite surfaces of the substrate. The slanted grating includes a plurality of ridges and is characterized by a grating period in one direction. The plurality of ridges is tilted at a slant angle with respect to a surface normal of the first surface and is characterized by a height. The height of the plurality of ridges, the grating period, and the slant angle are configured to cause destructive interference between ambient light diffracted by the slanted grating. In some embodiments, a difference between the height of the plurality of ridges and an integer multiple of the grating period divided by the tangent of the slant angle is less than a threshold value.