EYE TRACKING APPARATUS, METHOD AND SYSTEM

摘要

A transparent waveguide for use in eye tracking includes an input-coupler and an output-coupler. The input-coupler comprises a plurality of curved grating lines having a radially varying pitch. When positioned in front of an eye illuminated with infrared light, infrared light beams reflected from the eye and incident on the input-coupler enter the waveguide at the input-coupler, propagate through the waveguide by way of total internal reflections, and exit the waveguide proximate the output-coupler. The radially varying pitch of the curved grating lines of the input-coupler provides angular encoding of infrared light incident on the input-coupler, and more specifically, causes different beams of infrared light incident on respective different horizontal and vertical positions of the input-coupler to propagate through the waveguide at respective different angles of reflection and exit the waveguide at respective different angles of incidence relative to a surface of the waveguide through which infrared light beams exit.

主权项

1. An apparatus for use in tracking an eye that is illuminated by infrared light, the apparatus comprising:
a waveguide that is transparent and includes an input-coupler and an output-coupler that are spatially separated from one another; and a light source adapted to illuminate an eye with infrared light so that at least a portion of the infrared light is reflected from the eye and is incident on the input-coupler; wherein the input-coupler comprises a plurality of curved grating lines that are configured to diffract infrared light beams incident on the input-coupler into the waveguide and towards a common region at which is located the output-coupler by way of total internal reflections; wherein the plurality of curved grating lines of the input-coupler have a radially varying pitch that decreases with increases in distances between the curved grating lines and the output-coupler; and wherein the plurality of curved grating lines of the input-coupler each have a respective center of curvature and a respective point of convergence that are located within the region of the waveguide at which is located the output-coupler.