US Patent 11474395 Birefringent polymer based surface relief grating

A waveguide display includes a substrate transparent to at least one of visible or near infrared light, and a grating on the substrate. The grating includes ridges formed using a birefringent material and is configured to selectively couple incident light in a first polarization state into or out of the substrate. The birefringent material in the ridges is characterized by an optic axis parallel to a plane that includes a grating vector of the grating.