Eye-imaging apparatus using diffractive optical elements

Patent metadata

Field	Value
Publication number	US-11073695-B2
Application number	US-201815925505-A
Country	US
Kind code	B2
Filing date	Mar 19, 2018
Priority date	Mar 21, 2017
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

Examples of eye-imaging apparatus using diffractive optical elements are provided. For example, an optical device comprises a substrate having a proximal surface and a distal surface, a first coupling optical element disposed on one of the proximal and distal surfaces of the substrate, and a second coupling optical element disposed on one of the proximal and distal surfaces of the substrate and offset from the first coupling optical element. The first coupling optical element can be configured to deflect light at an angle to totally internally reflect (TIR) the light between the proximal and distal surfaces and toward the second coupling optical element, and the second coupling optical element can be configured to deflect at an angle out of the substrate. The eye-imaging apparatus can be used in a head-mounted display such as an augmented or virtual reality display.

First claim

What is claimed is:

1. An optical device comprising:
a camera assembly; and
a light directing assembly configured to direct light toward the camera assembly, the light directing assembly comprising:
a substrate having a proximal surface and a distal surface;
a first coupling optical element disposed on one of the proximal surface and the distal surface; and
a second coupling optical element disposed on one of the proximal surface and the distal surface and laterally offset from the first coupling optical element along a direction parallel to the proximal surface or the distal surface;

wherein the first coupling optical element is configured to deflect light at an angle to totally internally reflect (TIR) the light between the proximal and distal surfaces and toward the second coupling optical element, the second coupling optical element configured to deflect light at an angle out of the substrate and toward the camera assembly;
wherein the camera assembly is configured to capture an image using the light totally internally reflected within the substrate and deflected by the second coupling optical element; and
wherein the optical device is configured to display images at different depth planes by outputting light with different amounts of wavefront divergence corresponding to the different depth planes.

2. The optical device of claim 1 , wherein the substrate is transparent to visible light.

3. The optical device of claim 1 , wherein the substrate comprises a polymer.

4. The optical device of claim 1 , wherein the substrate comprises polycarbonate.

5. The optical device of claim 1 , wherein the first and second coupling optical elements are external to and fixed to at least one of the proximal and distal surfaces of the substrate.

6. The optical device of claim 1 , wherein the first and second coupling optical elements comprise a portion of the substrate.

7. The optical device of claim 1 , wherein at least one of the first and second coupling optical elements comprise a plurality of diffractive features.

8. The optical device of claim 7 , wherein the plurality of diffractive features have a relatively high diffraction efficiency for a range of wavelengths so as to diffract substantially all of the light of the range of wavelengths.

9. The optical device of claim 7 , wherein the plurality of diffractive features diffract light in at least one direction based in part on a period of the plurality of diffractive elements, wherein the at least one direction is selected to TIR the light between the proximal and distal surfaces.

10. The optical device of claim 1 , wherein at least one of the first or second coupling optical elements comprises at least one of an off-axis diffractive optical element (DOE), an off-axis diffraction grating, an off-axis diffractive optical element (DOE), an off-axis holographic mirror (OAHM), or an off-axis volumetric diffractive optical element (OAVDOE), or an off-axis cholesteric liquid crystal diffraction grating (OACLCG).

11. The optical device of claim 1 , wherein each of the first and second coupling optical elements are configured to deflect light of a first range of wavelengths while transmitting light of a second range of wavelengths.

12. The optical device of claim 11 , wherein the first range of wavelengths comprises light in at least one of the infrared (IR) or near-IR spectrum and the second range of wavelengths comprises light in the visible spectrum.

13. The optical device of claim 1 , wherein the first and second coupling optical elements selectively reflect light of a range of wavelengths, wherein the first coupling optical element is disposed on the distal surface of the substrate and the second coupling optical element is disposed on the proximal surface of the substrate.

14. The optical device of claim 1 , wherein the first and second coupling optical elements selectively transmit light of a range of wavelengths, wherein the first coupling optical element is disposed on the proximal surface of the substrate and the second coupling optical element is disposed on the distal surface of the substrate.

15. The optical device of claim 1 , wherein the first coupling optical element selectively reflects light of a range of wavelengths and the second coupling optical element selectively transmits light of the range of wavelengths, wherein the first and second coupling optical elements are disposed on the distal surface of the substrate.

16. The optical device of claim 1 , wherein the first coupling optical element selectively transmits light of a range of wavelengths and the second coupling optical element selectively reflects light of the range of wavelengths, wherein the first and second coupling optical elements are disposed on the proximal surface of the substrate.

17. A head mounted display (HMD) configured to be worn on a head of a user, the HMD comprising:
a frame;
a pair of optical elements supported by the frame such that each optical element of the pair of optical elements is capable of being disposed forward of an eye of the user; and
an imaging system comprising:
a camera assembly mounted to the frame; and
an optical device in accordance with claim 1 .

18. The HMD of claim 17 , wherein at least one optical element of the pair of optical elements comprises the substrate.

19. The HMD of claim 17 , wherein the substrate is disposed on a surface of at least one optical element of the pair of optical elements.

20. The HMD of claim 17 , wherein the frame comprises a pair of ear stems, and the camera assembly is mounted on one of the pair of ear stems.

21. The HMD of claim 17 , wherein the camera assembly is a forward facing camera assembly configured to image light received from the second coupling optical element.

22. The HMD of claim 17 , wherein the camera assembly is a backward facing camera assembly disposed in a direction facing toward the user, the backward facing camera assembly configured to image light received from the second coupling optical element.

23. The HMD of claim 17 , further comprising a light source emitting light of a first range of wavelengths toward at least one of: the eye of the user, a part of the eye, or a portion of tissue surrounding the eye.

24. The HMD of claim 23 , wherein the light of the first range of wavelengths is reflected toward the first coupling optical element by at least one of: the eye of the user, a part of the eye, or a portion of tissue surrounding the eye.

25. The HMD of claim 17 , wherein each of the pair of optical elements is transparent to visible light.

26. The HMD of claim 17 , wherein each of the pair of optical elements is configured to display an image to the user.

27. The HMD of claim 17 , wherein camera assembly is configured to image at least one of: the eye of the user, a part of the eye, or a portion of tissue surrounding the eye based, in part on, light received from the second coupling optical element.

28. The HMD of claim 27 , wherein the HMD is configured to track the gaze of the user based on the image of the at least one of the: eye of the user, the part of the eye, or the portion of tissue surrounding the eye.

29. The HMD of claim 27 , wherein the image imaged by the camera assembly is consistent with an image imaged by a camera placed in front of the eye of the user and directly viewing the at least one of the: eye of t

Assignees

• Magic Leap Inc

Inventors

• Gao Chunyu
• Oh Chulwoo
• Klug Michael Anthony
• Bluzer Evyatar

Classifications

• H04N2213/001

  Constructional or mechanical details · CPC title

• H04N13/383

  for tracking with gaze detection, i.e. detecting the lines of sight of the viewer's eyes · CPC title

• H04N13/344

  with head-mounted left-right displays · CPC title

• H04N13/332

  Displays for viewing with the aid of special glasses or head-mounted displays [HMD] · CPC title

• G02B2027/0187

  slaved to motion of at least a part of the body of the user, e.g. head, eye · CPC title