Patent ID: 7522344

Claim:
A projection-based head-mounted display device with an optical system inside the head-mounted display for eye-tracking capability, the optical eye tracking system comprising: multiple light sources for providing an infrared light to illuminate an eye of a user for creating multiple glints for use in detecting a polygon formed by the multiple glints, the multiple light source consisting of a dual light source for obtaining a bright pupil image and a dark pupil image of the eye, wherein the bright pupil image and the dark pupil image are subtracted to obtain a pupil of the eye for eye tracking; a camera for recording the multiple glints from the eye, the bright pupil image and the dark pupil image alternating with each frame taken by the camera; an optics for providing an optical path for a head-mounted display path and an eye-tracker path; a first and a second optical device for imaging the eye onto the camera, the optical device including a first and second hot mirror positioned in the eye-tracker path to reflect the infrared light and transmit a visible light; an interface for coupling an external controller with the head-mounted projection display for executing a set of instructions for controlling the projection-based head-mounted display device; and a display for displaying an image to the user, the display path shared with the eye eye-tracker path without obstructing the user's view, wherein the projection-based head-mounted display with eye-tracking capabilities built into the head-mounted device is compact, light-weight, comfortable and easy-to-use.