Method and device for image display and eye tracking through a catadioptric lens

1. An apparatus comprising:

a display to emit light in a first wavelength range;

one or more light sources to emit light in a second wavelength range;

a camera to detect the light in the second wavelength range; and

an eyepiece to reflect and refract the light in the first wavelength range while passing, without substantial refraction, the light in the second wavelength range, wherein the eyepiece includes two lens halves separated by a retarder that changes linearly polarized light to circularly polarized light in the first wavelength range and passes, without substantial refraction, the light in the second wavelength range.

2. The apparatus of claim 1 , wherein the first wavelength range is a visible wavelength range and the second wavelength range is a near-infrared wavelength range.

3. The apparatus of claim 1 , wherein the camera is disposed between the eyepiece and the display.

4. The apparatus of claim 1 , wherein the display is disposed between the eyepiece and the camera.

5. The apparatus of claim 1 , wherein the eyepiece is disposed between the camera and the display.

6. The apparatus of claim 1 , wherein the display is disposed less than five millimeters from the eyepiece, wherein the eyepiece provides a virtual distance of at least one meter.

7. The apparatus of claim 1 , wherein the eyepiece includes a catadioptric lens.

8. The apparatus of claim 1 , wherein the two lens halves of the eyepiece correspond to a split meniscus lens.

9. The apparatus of claim 8 , wherein the eyepiece includes a 50/50 mirror and a reflective polarizer, and wherein the retarder corresponds to a quarter wave retarder.

10. The apparatus of claim 9 , wherein the one or more light sources emit unpolarized light.

11. The apparatus of claim 9 , wherein the one or more light sources to emit circularly polarized light in the second wavelength range with a first circular orientation,

wherein the display emits circularly polarized light in the first wavelength range with a second circular orientation opposite the first circular polarization, and

wherein the quarter-wave retarder changes circularly polarized light to linearly polarized light in the first wavelength range and changes circularly polarized light to linearly polarized light in the second wavelength range.

12. The apparatus of claim 9 , wherein the 50/50 mirror is substantially transparent in the second wavelength range.

13. The apparatus of claim 1 , wherein the camera detects the light in the second wavelength range having been reflected off an eye of a user and passed through the eyepiece without substantial refraction.

14. An apparatus comprising:

a selectively distortive catadioptric eyepiece including two lens halves separated by a retarder;

a display to emit light in a first wavelength range through the selectively distortive catadioptric eyepiece, wherein the light in the first wavelength range is reflected and refracted by the selectively distortive catadioptric eyepiece, and wherein the retarder changes linearly polarized light to circularly polarized light in the first wavelength;

one or more light sources to emit light in a second wavelength range through the selectively distortive catadioptric eyepiece, wherein the light in the second wavelength range is passed, without substantial refraction, by the selectively distortive catadioptric eyepiece, and wherein the retarder passes, without substantial refraction, the light in the second wavelength range; and

a camera to detect the light in the second wavelength range that is reflected by an eye of a user.

15. The apparatus of claim 14 , wherein the first wavelength range is a visible wavelength range and the second wavelength range is a near-infrared wavelength range.

16. The apparatus of claim 14 , wherein the one or more light sources project a circle of glints onto the eye of a user.

17. The apparatus of claim 14 , further comprising a processor to track a gaze direction of the user based on the light in the second wavelength range that is reflected by the eye of the user.

18. The apparatus of claim 14 , wherein the one or more light sources are disposed less than thirty millimeters from the eye of the user.

19. The apparatus of claim 14 , wherein the selectively distortive catadioptric eyepiece includes a 50/50 mirror and a reflective polarizer, and wherein the retarder corresponds to a quarter wave retarder.

20. The apparatus of claim 14 , wherein the camera is hidden from a view of the user.

21. A method comprising:

projecting, using a display, an image comprising emitted light in a first wavelength through an eyepiece that reflects and refracts light in the first wavelength range while passing, without substantial refraction, light in a second wavelength range, wherein the eyepiece includes two lens halves separated by a retarder that changes linearly polarized light to circularly polarized light in the first wavelength range and passes, without substantial refraction, the light in the second wavelength range;

emitting, using one or more light sources, light in the second wavelength range through the eyepiece; and

detecting, using a camera, the light in the second wavelength range reflected by an eye of a user.

22. The method of claim 21 , wherein the one or more light sources emit the light in the second wavelength in a first direction, and wherein the camera detects the light in the second wavelength reflected by the eye of the user that passes through the eyepiece in a second direction opposite the first direction.