Systems and methods for mixed reality

Patent metadata

Field	Value
Publication number	US-10755481-B2
Application number	US-201815980947-A
Country	US
Kind code	B2
Filing date	May 16, 2018
Priority date	May 16, 2017
Publication date	Aug 25, 2020
Grant date	Aug 25, 2020

Abstract

A virtual image generation system comprises a planar optical waveguide having opposing first and second faces, an in-coupling (IC) element configured for optically coupling a collimated light beam from an image projection assembly into the planar optical waveguide as an in-coupled light beam, a first orthogonal pupil expansion (OPE) element associated with the first face of the planar optical waveguide for splitting the in-coupled light beam into a first set of orthogonal light beamlets, a second orthogonal pupil expansion (OPE) element associated with the second face of the planar optical waveguide for splitting the in-coupled light beam into a second set of orthogonal light beamlets, and an exit pupil expansion (EPE) element associated with the planar optical waveguide for splitting the first and second sets of orthogonal light beamlets into an array of out-coupled light beamlets that exit the planar optical waveguide.

First claim

What is claimed is:

1. A virtual image generation system comprising:
a planar optical waveguide comprising at least one semi-reflective interface and a plurality of light guiding sub-elements including a primary light guiding sub-element having a first thickness and at least one secondary light guiding sub-element having a second thickness, wherein
the at least one semi-reflective interface is disposed between the plurality of light guiding sub-elements, and
the first thickness is at least twice each of the second thickness;

an in-coupling (IC) element configured for optically coupling a collimated light beam from an image projection assembly for propagation as an in-coupled light beam within the planar optical waveguide;
multiple diffractive optical elements (DOEs) associated with the planar optical waveguide;
a first multiplier comprising the primary light guiding sub-element having the first thickness in the planar waveguide and one or more first DOEs of the multiple DOEs, wherein the first multiplier multiplies the in-coupled light beam from the in-coupling element into a plurality of primary light beamlets based at least in part upon a first cloning efficiency, and the first cloning efficiency is determined based at least in part upon the first thickness;
a second multiplier comprising the at least one secondary light guiding sub-element having a second thickness in the planar waveguide and one or more second DOEs in the multiple DOEs, wherein
the second multiplier receives light beamlets from the first multiplier and multiplies the light beamlets into an array of out-coupled light beamlets based at least in part upon a second cloning efficiency, and the second cloning efficiency is determined based at least in part upon the second thickness, and
a total number of light beamlets in the array of out-coupled light beamlets is based at least in part upon the first cloning efficiency and the second cloning efficiency for cloning the in-coupled light beam into the array of out-coupled light beamlets.

2. The virtual image generation system of claim 1 , wherein the first thickness is a non-multiple of the second thickness.

3. The virtual image generation system of claim 1 , wherein the second multiplier comprises a plurality of secondary substrates.

4. The virtual image generation system of claim 3 , wherein at least two secondary substrates of the plurality of secondary substrates have respective thicknesses that are substantially equal to each other.

5. The virtual image generation system of claim 3 , wherein at least two secondary substrates of the plurality of secondary substrates have respective thicknesses that are different from each other.

6. The virtual image generation system of claim 5 , wherein the first thickness is a non-multiple of at least one respective thickness of the respective thicknesses.

7. The virtual image generation system of claim 5 , wherein the respective thicknesses are non-multiples of each other.

8. The virtual image generation system of claim 1 , wherein the first thickness and the second thickness are selected such that a spacing value between centers of at least two adjacent light beamlets of the array of out-coupled light beamlets are equal to or less than a width of the collimated light beam.

9. The virtual image generation system of claim 1 , wherein the first thickness and the second are selected such that no gap resides between edges of greater than half of adjacent ones of the out-coupled light beamlets.

10. The virtual image generation system of claim 1 , wherein the first multiplier comprises a first reflective surface reflecting first incoming light in a first direction and a second reflective surface reflect second incoming light in a second direction, and the second multiplier comprises only one reflective surface that reflects third incoming light in a third direction that is substantially identical to the second direction.

11. The virtual image generation system of claim 10 , wherein the second thickness of the at least one secondary light guiding sub-element are configured such that at least a portion of beamlets reflected from the only one reflective surface overlaps beamlets reflected from the second reflective surface of the first multiplier, wherein the at least one semi-reflective surface comprises a coating that is disposed between the plurality of light guiding sub-elements via one of physical vapor deposition (PVD), ion-assisted deposition (IAD), or ion beam sputtering (IBS).

12. The virtual image generation system of claim 10 , wherein each of the at least one semi-reflective coating one or more of a metal layer, a dielectric layer, and a semiconductor layer.

13. The virtual image generation system of claim 1 , wherein the first light guiding sub-element and the second light guiding sub-element of the plurality of light guiding sub-elements are composed of materials having different indices of refraction.

14. The virtual image generation system of claim 1 , wherein the multiple DOEs comprise an orthogonal pupil expansion (OPE) element that splits at least two in-coupled light beamlets into at least two sets of orthogonal light beamlets, the at least one semi-reflective interface splits the at least two sets of orthogonal light beamlets into at least four sets of orthogonal light beamlets, the multiple DOEs comprise an exit pupil expansion (EPE) element that spits the at least four sets of orthogonal light beamlets into the array of out-coupled light beamlets.

15. The virtual image generation system of claim 14 , wherein the OPE element and EPE element are disposed on a same face of the optical planar waveguide.

16. The virtual image generation system of claim 14 , wherein the at least two in-coupled light beamlets propagate within the planar optical waveguide via total internal reflection (TIR) along a first optical path that intersects the OPE element such that a portion of the at least two in-coupled light beamlets is diffracted as the at least two sets of orthogonal light beamlets that propagate within the planar optical waveguide via TIR along second parallel optical paths.

17. The virtual image generation system of claim 16 , wherein the second parallel optical paths are orthogonal to the first optical path.

18. The virtual image generation system of claim 16 , wherein the at least two sets of orthogonal light beamlets intersect the EPE element such that a portion of the at least two sets of orthogonal light beamlets is diffracted as the array of out-coupled light beamlets out of a face of the planar optical waveguide.

19. The virtual image generation system of claim 14 , wherein the EPE element imparts a convex wavefront profile on the array of out-coupled light beamlet exiting the planar optical waveguide, the convex wavefront profile having a center of radius at a focal point to produce an image at a given focal plane.

20. The virtual image generation system of claim 1 , wherein the collimated light beam defines an entrance pupil, and the array of out-coupled light beamlets defines an exit pupil that is larger than the entrance pupil.

21. The virtual image generation system of claim 20 , wherein the exit pupil is at least ten times larger than the entrance pupil.

22. The virtual image generation system of claim 20 , wherein the exit pupil is at least one hundred times larger than the entrance pupil.

23. The virtual image generation system of claim 1 , wherein the array of out-coupled light beamlets

Assignees

• Magic Leap Inc

Inventors

• Schowengerdt Brian T
• Watson Mathew D
• Tinch David
• Yeoh Ivan Li Chuen
• Macnamara John Graham
• Edwin Lionel Ernest
• Klug Michael Anthony
• Welch William Hudson

Classifications

• G02B2027/0123

  comprising devices increasing the field of view · CPC title

• G02B6/005

  provided by one optical element, or plurality thereof, placed on the light output side of the light guide · CPC title

• G02B27/0081 Primary

  with means for altering, e.g. enlarging, the entrance or exit pupil · CPC title

• G02B2027/0178

  Eyeglass type (eyeglass details G02C) · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title