Patent 11150468 was granted and assigned to Facebook on October, 2021 by the United States Patent and Trademark Office.
An optical device and an eye-tracking system to suppress a rainbow effect are provided. The optical device includes a grating. The grating includes at least one substrate and a grating structure coupled to the at least one substrate. The grating structure is configured to diffract an infrared light beam and transmit a visible light beam with a diffraction efficiency less than a predetermined threshold.