Method of fabricating diffraction gratings

Patent metadata

Field	Value
Publication number	US-12372695-B2
Application number	US-202318400891-A
Country	US
Kind code	B2
Filing date	Dec 29, 2023
Priority date	Jul 19, 2019
Publication date	Jul 29, 2025
Grant date	Jul 29, 2025

Abstract

A method of fabricating a blazed diffraction grating comprises providing a master template substrate and imprinting periodically repeating lines on the master template substrate in a plurality of master template regions. In some embodiments, the periodically repeating lines in different ones of the master template regions extend in different directions. The method additionally comprises using at least one of the master template regions as a master template to imprint at least one blazed diffraction grating pattern on a grating substrate. In some embodiments, the method further comprises coating the periodically repeating lines with a material having a greater hardness than the material that forms the lines.

First claim

What is claimed is:

1. A method of fabricating one or more diffraction gratings, the method comprising:
providing a master template substrate;
imprinting periodically repeating lines on the master template substrate in a plurality of master template regions, wherein the periodically repeating lines are formed of a first material;
conformally coating the periodically repeating lines with a second material having a greater hardness than the first material; and
using one or more master template regions as a master template to imprint one or more blazed diffraction grating patterns on a grating substrate.

2. The method of claim 1 , wherein the periodically repeating lines in different ones of the master template regions extend in different directions.

3. The method of claim 1 , wherein the periodically repeating lines in different ones of the master template regions extend in different radial directions with respect to a central axis of the master template substrate.

4. The method of claim 1 , wherein imprinting periodically repeating lines on the master template substrate comprises imprinting in at least four master template regions.

5. The method of claim 1 , wherein the periodically repeating lines formed on the master template substrate comprise symmetric opposing side surfaces forming similar angles with respect to a plane of the master template substrate.

6. The method of claim 1 , wherein the periodically repeating lines formed on the master template substrate comprise asymmetric opposing side surfaces forming different angles with respect to a plane of the master template substrate.

7. The method of claim 1 , wherein the periodically repeating lines formed on the master template comprise a polymeric material.

8. The method of claim 1 , wherein the periodically repeating lines formed on the master template substrate comprise a dielectric material.

9. The method of claim 1 , wherein the second material comprises one or more of a dielectric material, a metal oxide, a metal nitride, a metal, or a metal alloy.

10. The method of claim 1 , wherein the grating substrate is a waveguide, and wherein the blazed diffraction grating comprises an outcoupling grating configured to outcouple light from the waveguide.

11. The method of claim 1 , wherein the grating substrate is a waveguide, and wherein the blazed diffraction grating comprises a light distributing element configured to distribute and propagate light within the waveguide towards an outcoupling element.

12. The method of claim 1 , wherein the grating substrate is a waveguide, and wherein the blazed diffraction grating serves as a combined outcoupling grating and light distributing element configured to distribute and propagate light within the waveguide and further configured to outcouple the light from the waveguide.

13. The method of claim 1 , wherein the one or more blazed diffraction grating patterns comprise a plurality of straight lines.

14. The method of claim 1 , wherein the one or more blazed diffraction grating patterns comprise a plurality of discontinuous lines.

15. The method of claim 1 , wherein the one or more blazed diffraction grating patterns comprise a plurality of pillars protruding from a surface of the grating substrate.

16. The method of claim 1 , wherein the one or more blazed diffraction grating patterns comprise a plurality of straight lines, wherein at least some of the straight lines have different widths.

17. The method of claim 1 , wherein the one or more blazed diffraction grating patterns comprise diffractive features arranged as a one-dimensional (1D) array having a periodicity in one lateral direction, and wherein the 1D array serves as a 1D grating configured to diffract light preferentially in one direction.

18. The method of claim 1 , wherein the one or more blazed diffraction grating patterns comprise diffractive features arranged as a two-dimensional (2D) array having periodicities in two lateral directions, and wherein the 2D array serves as a 2D grating configured to diffract light preferentially in two directions.

19. The method of claim 18 , wherein the 2D array comprises the same number of diffractive features in two different lateral directions.

20. A method of fabricating one or more diffraction gratings, the method comprising:
providing a master template substrate;
imprinting periodically repeating lines on the master template substrate in a plurality of master template regions, wherein the periodically repeating lines are formed of a first material, and wherein the periodically repeating lines in different ones of the master template regions extend in different radial directions with respect to a central axis of the master template substrate;
coating the periodically repeating lines with a second material having a greater hardness than the first material; and
using one or more master template regions as a master template to imprint one or more blazed diffraction grating patterns on a grating substrate.

Assignees

• Magic Leap Inc

Inventors

• Yang Shuqiang
• Luo Kang
• Singh Vikramjit
• Xu Frank Y

Classifications

• G02B5/1842

  Gratings for image generation (G02B5/1847 takes precedence) · CPC title

• G02B27/0172

  characterised by optical features · CPC title

• G02B2027/0125

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

• G02B27/4272

  having plural diffractive elements positioned sequentially along the optical path · CPC title

• G02B5/1857 Primary

  using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams · CPC title