EYE-TRACKING SYSTEM FOR HEAD-MOUNTED DISPLAY

• US 20140375790A1
• Filed: 06/25/2013
• Published: 12/25/2014
• Est. Priority Date: 06/25/2013
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Jr., James Peele Terrell
• Inventors: Robbins, Steve, McEldowney, Scott, Lou, Xinye, Nister, David, Steedly, Drew, Bohn, David D., Goris, Andrew C., Ackerman, Nathan, Miller, Quentin Simon Charles, Terrell, James Peele Jr.
• Granted Patent: US 10,228,561 B2
• Time in Patent Office: Days
• US Class Current: 348/78
• CPC Class Codes: G02B 2027/0138 comprising image capture systems, e.g. camera
• CPC Class Codes: G02B 2027/0187 slaved to motion of at least a part of the body of the user, e.g. head, eye
• CPC Class Codes: G02B 27/0093 with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/04 Prisms

Abstract

Embodiments are disclosed for a see-through head-mounted display system. In one embodiment, the see-through head-mounted display system comprises a freeform prism, and a display device configured to emit display light through the freeform prism to an eye of a user. The see-through head-mounted display system may also comprise an imaging device having an entrance pupil positioned at a back focal plane of the freeform prism, the imaging device configured to receive gaze-detection light reflected from the eye and directed through the freeform prism.

Claims

1. A see-through head-mounted display system comprising:

an illumination prism;

a freeform prism having positive optical power;

a display device configured to emit display light through the illumination prism and the freeform prism to an eye of a user; and

an imaging device configured to receive gaze-detection light reflected from the eye and directed through the freeform prism and the illumination prism.

2. The see-through head-mounted display system of claim 1, further comprising a frame configured to position the freeform prism at a viewing location relative to the eye.

3. The see-through head-mounted display system of claim 1, wherein the display device comprises an illumination light source and a liquid crystal on silicon (LCoS) micro-display, the illumination light source configured to direct light through the illumination prism to the LCoS.

4. The see-through head-mounted display system of claim 1, further comprising a glint source configured to emit the gaze-detection light.

5. The see-through head-mounted display system of claim 4, wherein the illumination prism comprises a beam splitter, the beam splitter configured to transmit display light from the display device to the freeform prism, reflect the gaze-detection light from the glint source to the freeform prism, and reflect the gaze-detection light as reflected from the eye through the freeform prism.

6. The see-through head-mounted display system of claim 5, wherein the imaging device images through a first side of the illumination prism and the display device emits the display light through a second side of the illumination prism, the first side being adjacent to the second side.

7. The see-through head-mounted display system of claim 5, wherein the glint source emits the gaze-detection light through the first side of the illumination prism.

8. The see-through head-mounted display system of claim 1, further comprising a user-facing compensator and an outward-facing compensator, the freeform prism positioned between the user-facing compensator and the outward-facing compensator, and an eye-side surface of the user-facing compensator being substantially parallel to an environment-side surface of the outward-facing compensator.

9. The see-through head-mounted display system of claim 8, wherein the user-facing compensator and the outward-facing compensator each have a substantially similar index of refraction as the freeform prism.

10. The see-through head-mounted display system of claim 1, wherein the freeform prism comprises at least three surfaces, each surface being non-planar and non-spherical.

11. The see-through head-mounted display system of claim 10, wherein the at least three surfaces includes a user-facing total internal reflective surface.

12. The see-through head-mounted display system of claim 11, wherein the at least three surfaces further includes an outward-facing surface opposite the user-facing total internal reflective surface, the outward-facing surface having a coating that is highly reflective for infrared light and partially reflective for visible light.

13. The see-through head-mounted display system of claim 1, wherein an angle between a visual axis of the eye and an optical axis of the imaging device is less than 90 degrees.

14. A see-through head-mounted display system comprising:

a freeform prism having positive optical power;

a display device configured to emit display light through the freeform prism to an eye of a user; and

an imaging device configured to receive gaze-detection light reflected from the eye and directed through the freeform prism.

15. The see-through head-mounted display system of claim 14, wherein the glint source comprises at least one infrared light source.

16. The see-through head-mounted display system of claim 15, further comprising an illumination prism comprising a beam splitter, the beam splitter configured to transmit visible light, reflect the gaze-detection light from the glint source to the freeform prism, and reflect the gaze-detection light as reflected from the eye through the freeform prism to the imaging device.

17. The see-through head-mounted display system of claim 16, wherein the glint source is positioned on a same side of the illumination prism as the imaging device.

18. A method of performing gaze-detection with a see-through head-mounted display system, the method comprising:

emitting display light through an illumination prism and a freeform prism having positive optical power to an eye of a user;

receiving gaze-detection light reflected from the eye and directed through the freeform prism and the illumination prism; and

determining gaze direction from the gaze-detection light reflected from the eye.

19. The method of claim 18, further comprising emitting gaze detection light through the illumination prism and the freeform prism to the eye.

20. The method of claim 18, further comprising storing the gaze direction and information associated with the gaze-detection light for use in future gaze direction determinations.