Compact eye-tracked head-mounted display
Eye-tracked head-mounted displays are provide which, in one aspect, may utilize the same optics for eyetracking and image viewing, with a selected portion of the optics used for an eyetracking optical path and a selected portion of the display optics used for an image viewing optical path.
1. An eye-tracked head-mounted display for use with a micro-display for displaying an image to an exit pupil thereof for viewing by a user, comprising: an illumination source having an illumination optical axis associated therewith; a prism lens in optical communication with the illumination source, the prism lens having a first surface located proximate and configured to receive light from the illumination source without illuminating the micro-display and having a second surface configured to transmit the light received by the first surface through the second surface to the exit pupil, at least one of the first and second surfaces comprising a free form surface, the illumination optical axis extending from the illumination source through the prism lens to the exit pupil; and an eyetracking sensor having a sensor optical axis associated therewith that extends through the prism lens from the exit pupil to the sensor, the sensor located proximate the first surface of the prism lens to receive optical radiation reflected from a user's eye positioned at the exit pupil and transmitted through the prism lens along the sensor optical path to the sensor, wherein the illumination optical axis and the sensor optical axis are tilted with respect to one another at the exit pupil.
2. The eye-tracked head-mounted display according to claim 1 , comprising a stop having at least one aperture therein disposed at a location along the sensor optical axis between the sensor and the first surface.
3. The eye-tracked head-mounted display according to claim 2 , wherein the at least one aperture comprises a pin-hole.
4. The eye-tracked head-mounted display according to claim 1 , wherein the prism lens comprises an aspheric surface.
5. The eye-tracked head-mounted display according to claim 1 , wherein the prism lens comprises a TIR (total internal reflection) surface oriented to receive and totally internally reflect light received from the illumination source.
6. The eye-tracked head-mounted display according to claim 1 , comprising a freeform corrective lens in optical communication with the prism lens.