Method and system for variable optical thickness waveguides for augmented reality devices

Patent metadata

Field	Value
Publication number	US-12399320-B2
Application number	US-202217705202-A
Country	US
Kind code	B2
Filing date	Mar 25, 2022
Priority date	Feb 14, 2019
Publication date	Aug 26, 2025
Grant date	Aug 26, 2025

Abstract

An augmented reality device includes a projector, projector optics optically coupled to the projector, and an eyepiece optically coupled to the projector optics. The eyepiece includes an eyepiece waveguide characterized by lateral dimensions and an optical path length difference as a function of one or more of the lateral dimensions.

First claim

What is claimed is:

1. An augmented reality device comprising:
a projector;
projector optics optically coupled to the projector; and
an eyepiece optically coupled to the projector optics, wherein the eyepiece comprises an eyepiece waveguide including a uniform thickness portion, a tapered portion, a thinner portion, a diffractive incoupling element, and a diffractive outcoupling element, wherein the eyepiece waveguide is characterized by lateral dimensions and an eyepiece waveguide optical thickness that decreases from the uniform thickness portion of the eyepiece waveguide to the thinner portion of the eyepiece waveguide as a function of one or more of the lateral dimensions, wherein the diffractive incoupling element is located adjacent the uniform thickness portion of the eyepiece waveguide and the diffractive outcoupling element is located at the thinner portion of the eyepiece waveguide.

2. The augmented reality device of claim 1 wherein the eyepiece further comprises:
a second eyepiece waveguide characterized by second lateral dimensions and a second optical path length difference as a function of one or more of the second lateral dimensions; and
a third eyepiece waveguide characterized by third lateral dimensions and a third optical path length difference as a function of one or more of the third lateral dimensions.

3. The augmented reality device of claim 2 wherein the eyepiece waveguide, the second eyepiece waveguide, and the third eyepiece waveguide form the eyepiece.

4. The augmented reality device of claim 3 wherein the eyepiece is a laminated structure including the eyepiece waveguide, the second eyepiece waveguide, and the third eyepiece waveguide.

5. The augmented reality device of claim 2 further comprising:
a second projector;
second projector optics optically coupled to the second projector; and
a second eyepiece optically coupled to the second projector optics, wherein the second eyepiece comprises a fourth eyepiece waveguide characterized by fourth lateral dimensions and a fourth optical path length difference as a function of one or more of the fourth lateral dimensions.

6. The augmented reality device of claim 5 wherein the second eyepiece further comprising:
a fifth eyepiece waveguide characterized by fifth lateral dimensions and a fifth optical path length difference as a function of one or more of the fifth lateral dimensions; and
a sixth eyepiece waveguide characterized by sixth lateral dimensions and a sixth optical path length difference as a function of one or more of the sixth lateral dimensions.

7. The augmented reality device of claim 2 wherein:
the diffractive outcoupling element of the eyepiece waveguide comprises a combined pupil expander;
the second eyepiece waveguide comprises a second combined pupil expander; and
the third eyepiece waveguide comprises a third combined pupil expander, wherein a thickness of the eyepiece waveguide varies across the combined pupil expander, a thickness of the second eyepiece waveguide varies across the second combined pupil expander, and a thickness of the third eyepiece waveguide varies across the third combined pupil expander.

8. The augmented reality device of claim 1 wherein the projector, the projector optics, and the eyepiece are mounted in an augmented reality headset.

9. The augmented reality device of claim 1 wherein the eyepiece waveguide is characterized by an index of refraction variation as a function of the one more of the lateral dimensions.

10. The augmented reality device of claim 1 , wherein the projector, the projector optics, and the eyepiece are configured such that light from the projector passes through the projector optics and enters the eyepiece waveguide at the diffractive incoupling element located adjacent the uniform thickness portion of the eyepiece waveguide.

11. The augmented reality device of claim 10 , wherein the diffractive outcoupling element located at the thinner portion of the eyepiece waveguide is configured such that the light that enters the eyepiece waveguide at the diffractive incoupling element traverses the eyepiece waveguide from the tapered portion to the thinner portion and exits the eyepiece waveguide through the diffractive outcoupling element located at the thinner portion of the eyepiece waveguide.

12. The augmented reality device of claim 1 wherein the tapered portion is positioned between the uniform thickness portion and the thinner portion.

13. The augmented reality device of claim 1 wherein the tapered portion of the eyepiece waveguide is characterized by a nonlinear cross section.

14. The augmented reality device of claim 13 wherein the nonlinear cross section comprises a domed shape.

15. The augmented reality device of claim 1 wherein the eyepiece waveguide comprises:
a substrate; and
a variable thickness layer coupled to the substrate.

16. An augmented reality device comprising:
a projector;
projector optics optically coupled to the projector; and
an eyepiece optically coupled to the projector optics, wherein the eyepiece comprises an eyepiece waveguide characterized by lateral dimensions and one or more layers, wherein at least one of the one or more layers includes a uniform thickness portion, a tapered portion, a thinner portion, a diffractive incoupling element, and a diffractive outcoupling element, wherein the eyepiece waveguide is characterized by an eyepiece waveguide optical thickness that varies decreases from the uniform thickness portion of the eyepiece waveguide to the thinner portion of the eyepiece waveguide as a function of one or more of the lateral dimensions, wherein the diffractive incoupling element is adjacent the uniform thickness portion of the eyepiece waveguide and the diffractive outcoupling element is at the thinner portion of the eyepiece waveguide.

17. The augmented reality device of claim 16 wherein the eyepiece comprises:
a substrate; and
a variable thickness layer coupled to the substrate.

18. The augmented reality device of claim 17 wherein an index of refraction of the substrate is substantially equal to an index of refraction of the variable thickness layer.

19. The augmented reality device of claim 16 wherein the eyepiece further comprises:
a second eyepiece waveguide characterized by second lateral dimensions and one or more second layers, wherein at least one of the one or more second layers is characterized by a second optical path length difference as a function of one or more of the second lateral dimensions; and
a third eyepiece waveguide characterized by third lateral dimensions and one or more third layers, wherein at least one of the one or more third layers is characterized by a third optical path length difference as a function of one or more of the third lateral dimensions.

20. The augmented reality device of claim 19 wherein the eyepiece waveguide, the second eyepiece waveguide, and the third eyepiece waveguide form the eyepiece.

21. The augmented reality device of claim 20 wherein the eyepiece is a laminated structure including the eyepiece waveguide, the second eyepiece waveguide, and the third eyepiece waveguide.

22. The augmented reality device of claim 19 wherein:
the one or more layers, the one or more second layers, and the one or more third layers are characterized by a thickness variation as a function of the one or more lateral dimensions; and
the thickness variation of each of the one or more layers, the one or more second layers, and the one

Assignees

• Magic Leap Inc

Inventors

• Tekolste Robert D
• Ong Ryan Jason
• LIU Victor Kai
• Bhargava Samarth
• Peroz Christophe
• Singh Vikramjit
• Menezes Marlon Edward
• Yang Shuqiang
• Xu Frank Y

Classifications

• G02B6/0046

  Tapered light guide, e.g. wedge-shaped light guide · CPC title

• G02B2006/12061

  Silicon · CPC title

• G02B2006/12069

  Organic material · CPC title

• G02B2006/12038

  Glass (SiO2 based materials) · CPC title

• G02B2006/12197

  Grinding; Polishing · CPC title