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 displaying an image to an exit pupil thereof for viewing by a user, comprising:
a micro-display for generating the image to be viewed by the user, the micro-display having a display optical path extending from the microdisplay to the exit pupil;
a freeform optical prism in optical communication with the micro-display along the display optical path between the prism and the exit pupil with the micro-display optically conjugate to the exit pupil, the prism having a selected surface closest to the micro-display;
an illumination source disposed at a location to illuminate the selected surface of the freeform optical prism with optical radiation from the illumination source without illuminating the micro-display, the freeform optical prism configured to transmit the optical radiation therethrough from the selected surface to the exit pupil to illuminate the exit pupil about the center of the exit pupil; and
an eyetracking sensor having a sensor optical path associated therewith that extends through the freeform optical prism from the exit pupil to the sensor, the eyetracking sensor located proximate the selected surface of the freeform optical prism to receive optical radiation reflected from a user's eye positioned at the exit pupil and transmitted through the prism along the sensor optical path to the sensor, the sensor optically conjugate to the exit pupil across the prism.
2. The eye-tracked head-mounted display according to claim 1 , wherein the display and eyetracking sensor optical paths partially overlap at the selected surface.
3. The eye-tracked head-mounted display according to claim 1 , wherein the freeform optical prism is configured to create a virtual eyetracking of the micro-display for viewing at the exit pupil.
4. 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 path between the sensor and selected surface.
5. The eye-tracked head-mounted display according to claim 4 , wherein the at least one aperture comprises a pin-hole.
6. The eye-tracked head-mounted display according to claim 1 , wherein the prism comprises a wedge-shaped prism.
7. The eye-tracked head-mounted display according to claim 1 , wherein the prism comprises an aspheric surface.
8. The eye-tracked head-mounted display according to claim 1 , wherein the prism is telecentric in display space.
9. The eye-tracked head-mounted display according to claim 1 , wherein the prism is non-telecentric in display space.
10. The eye-tracked head-mounted display according to claim 1 , wherein the prism comprises a TIR (total internal reflection) surface oriented to receive and totally internally reflect light from the micro-display.
11. The eye-tracked head-mounted display according to claim 1 , wherein the prism comprises a TIR (total internal reflection) surface oriented to totally internally reflect light to the eyetracking sensor.
12. The eye-tracked head-mounted display according to claim 1 , comprising a freeform corrective lens in optical communication with the prism.