US Patent 11016341 Directional illumination apparatus and privacy display

A directional illumination apparatus comprises a waveguide with a reflective surface comprising reflective pairs of light input facets, reflective light extraction facets and an output transmissive surface. An array of micro-LEDs is arranged to illuminate the reflective surface in a rearwards direction. The pairs of light input facets direct light within the waveguide and reflective light extraction facets cooperate to provide a uniform output illumination across the output aperture of the waveguide with collimated light. A thin and efficient illumination apparatus may be used for high dynamic range display backlighting, privacy display or environmental illumination applications.