Metasurface optical coupling elements for a display waveguide

Patent metadata

Field	Value
Publication number	US-10838110-B2
Application number	US-201715449869-A
Country	US
Kind code	B2
Filing date	Mar 3, 2017
Priority date	Mar 3, 2017
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

Embodiments are disclosed for an optical waveguide display configured for use with a near-eye display (NED) device. In an embodiment the waveguide display includes a light-transmissive substrate and an optical coupling element configured to input light rays to the substrate or output light rays from the substrate, the optical coupling element configured to deflect a plurality of wavelengths of an incident light ray collinearly for propagation within the light-transmissive substrate through total internal reflection (TIR). The optical coupling element can include a pattern of nano-structures that collectively form a metasurface on the substrate.

First claim

What is claimed is:

1. An optical waveguide comprising:
a light-transmissive substrate including a plurality of internally reflective surfaces; and
an achromatic optical coupling element comprising a metasurface configured to input light rays to the light-transmissive substrate or output light rays from the light-transmissive substrate without separating the light rays into constituent colors, the achromatic optical coupling element configured to deflect a plurality of wavelengths of an incident light ray collinearly for propagation within the light-transmissive substrate through total internal reflection (TIR), wherein the metasurface of the achromatic optical coupling element includes a pattern of sub-wavelength nano-structures arranged on or proximate to at least a first surface of the plurality of internally reflective surfaces of the light-transmissive substrate.

2. The optical waveguide of claim 1 , wherein the pattern of sub-wavelength nano-structures is arranged to deflect the plurality of wavelengths of the incident light ray by causing a phase shift in the incident light ray.

3. The optical waveguide of claim 1 , wherein a spacing between structures in the pattern of sub-wavelength nano-structures is smaller than each of the plurality of wavelengths of the incident light ray.

4. The optical waveguide of claim 1 , wherein the pattern of sub-wavelength nano-structures is aperiodic.

5. The optical waveguide of claim 1 , wherein the structures forming the pattern of sub-wavelength nano-structures comprise dielectric resonators.

6. The optical waveguide of claim 1 , wherein the structures forming the pattern of sub-wavelength nano-structures include titanium dioxide.

7. The optical waveguide of claim 1 , wherein the plurality of wavelengths of the incident light ray include light in a:
red spectrum;
green spectrum; and
blue spectrum.

8. The optical waveguide of claim 1 , arranged as part of a pupil relay system in a near eye display (NED) device, the pupil relay system arranged to translate light rays from an image generator of the NED device to an eye of a user of the NED device.

9. The optical waveguide of claim 8 , wherein the achromatic optical coupling element is an in-coupling element arranged to input light rays received from the image generator of the NED device into the light-transmissive substrate.

10. The optical waveguide of claim 8 , wherein the achromatic optical coupling element is an out-coupling element arranged to output light rays from the light-transmissive substrate and to direct the light rays along an optical path for transmission to the eye of the user of the NED device.

11. The optical waveguide of claim 1 , further comprising:
a second light-transmissive substrate including another plurality of internally reflective surfaces; and
a second optical coupling element comprising a metasurface configured to input light rays to the second light-transmissive substrate or output light rays from the second light-transmissive substrate, the second optical coupling element configured to deflect a particular wavelength of the incident light ray collinearly for propagation within the second light-transmissive substrate through TIR, the particular wavelength different than said plurality of wavelengths.

12. The optical waveguide of claim 11 , wherein the plurality of wavelengths of the incident light ray include light in a green spectrum and a blue spectrum; and
wherein the particular wavelength of the incident light ray includes light in a red spectrum.

13. The optical waveguide of claim 1 , wherein the achromatic optical coupling element further includes:
a second pattern of sub-wavelength nano-structures arranged on or proximate to at least a second surface of the plurality of internally reflective surfaces of the light-transmissive substrate, the second surface opposite the first surface of the light-transmissive substrate;
wherein the second pattern of sub-wavelength nano-structures arranged on or proximate to the second surface of the light-transmissive substrate is configured to deflect a different wavelength of the incident light ray than the pattern of sub-wavelength nano-structures on or proximate to the first surface of the light-transmissive substrate.

14. The optical waveguide of claim 1 , wherein the light-transmissive substrate includes glass.

15. A near-eye display (NED) device comprising:
a light-emitting microdisplay imager configured to emit light rays that collectively form a generated image; and
an optical waveguide including:
a light-transmissive substrate including a plurality of internally reflective surfaces;
an optical in-coupling element configured to input light rays received from the light-emitting microdisplay imager into the light-transmissive substrate, the optical in-coupling element configured to deflect a plurality of wavelengths of an incident light ray collinearly for propagation within the light-transmissive substrate through total internal reflection (TIR), wherein the optical in-coupling element includes a first pattern of structures arranged on or proximate to at least a first surface location of the plurality of internally reflective surfaces of the light-transmissive substrate; and
an optical out-coupling element configured to output light rays from the light-transmissive substrate to an eye of a user of the NED device, the optical out-coupling element configured to deflect the plurality of wavelengths collinearly towards the eye of the user, wherein the optical out-coupling element includes a second pattern of structures arranged on or proximate to at least a second surface location of the plurality of internally reflective surfaces of the light-transmissive substrate.

16. A method of manufacturing a waveguide display, comprising:
forming a layer of a resist material on a first surface of a light-transmissive substrate that has a plurality of internally reflective surfaces;
applying a beam of electrons to the layer of the resist material to form a pattern in the resist material;
filling at least a portion of the pattern with a dielectric material; and
removing remaining resist material to produce a pattern of sub-wavelength dielectric nano-structures on the first surface of the light-transmissive substrate providing an achromatic optical coupling element comprising a metasurface configured to input light rays to the light-transmissive substrate or output light rays from the light-transmissive substrate without separating the light rays into constituent colors, the achromatic optical coupling element, wherein the pattern of dielectric structures is such that, when in use, a plurality of wavelengths of an incident light ray are deflected collinearly for propagation within the light-transmissive substrate through total internal reflection (TIR).

17. The method of claim 16 , wherein the dielectric material comprises titanium dioxide.

18. The method of claim 16 , wherein producing the pattern of sub-wavelength dielectric nano-structures comprises producing an aperiodic pattern.

Assignees

• Microsoft Technology Licensing Llc

Inventors

• Glik Eliezer
• Edelstain Hagar
• Kress Bernard C

Classifications

• G02B2027/0125

  Field-of-view increase by wavefront division · CPC title

• G02B2027/0112

  comprising device for genereting colour display · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B6/005

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

• G02B6/0026 Primary

  Wavelength selective element, sheet or layer, e.g. filter or grating · CPC title