Cogni Trax
Cogni Trax is a company that has developed hard edge occlusion for optical see through displays, called Alpha Pix. It is based in Silicon Valley.
It is a display photonics startup company focusing on unique visual experience for AR smart glasses applications.
Their technology uses at least one SLM and quarter wave plate to cancel out light.[1]
Alpha Pix
The Alpha Pix platform uses a catadioptric combiner in a thin form factor for AR smart glasses. Alpha Pix controls per-pixel transparency in the virtual image plane, so it is possible to display virtual imagery in a black color. The black imagery can hard-edge occlude physical objects in the real background scene, making the generated black content visible even in direct sun-lit environments.
Alpha Pix only displays the color black. In total, it only consumes about 70mW of power.
The Alpha Pix CMOS display panel is designed like a smartphone camera, where the imaging lens is integrated directly on the CMOS panel. Alpha Pix uses a catadioptric combiner, which allows a compact folded optical path that enables very high optical efficiency between 25 percent and 75 percent.
Alpha Pix technology is patented in U.S. patent US10983355B2.