Uv and visible light exit grating for eyepiece fabrication and operation

Patent metadata

Field	Value
Publication number	US-2024377570-A1
Application number	US-202218692330-A
Country	US
Kind code	A1
Filing date	Sep 15, 2022
Priority date	Sep 16, 2021
Publication date	Nov 14, 2024
Grant date	—

Abstract

A method of forming a waveguide for an eyepiece for a display system to reduce optical degradation of the waveguide during segmentation is disclosed herein. The method includes providing a substrate having top and bottom major surfaces and a plurality of surface features, and using a laser beam to cut out a waveguide from said substrate by cutting along a path contacting and/or proximal to said plurality of surface features. The waveguide has edges formed by the laser beam and a main region and a peripheral region surrounding the main region. The peripheral region is surrounded by the edges.

First claim

1 . A method of forming a waveguide for an eyepiece for a display system, said method comprising:
providing a substrate having top and bottom major surfaces and a plurality of surface features; and using a laser beam to cut out a waveguide from said substrate by cutting along a path contacting and/or proximal to said plurality of surface features, said waveguide having edges formed by said laser beam and a main region and a peripheral region surrounding said main region, said peripheral region surrounded by said edges.

2 . The method of claim 1 , further comprising forming said plurality of surface features in said substrate.

3 . The method of claim 1 , further comprising forming said plurality of surface features in said substrate using nano-imprinting.

4 . The method of claim 1 , wherein the plurality of surface features is configured such that at least some of said laser light that is coupled into said waveguide is directed out of said waveguide by said plurality of surface features.

5 . The method of claim 1 , wherein the plurality of surface features comprises a diffraction grating.

6 . The method of claim 1 , wherein the plurality of surface features comprises a blazed grating.

7 . The method of claim 1 , wherein a plurality of said surface features have at least one sloping surface.

8 . The method of claim 1 , wherein a plurality of said surface features have two sloping surfaces.

9 . The method of claim 1 , wherein a plurality of said surface features have a sawtooth shape.

10 . The method of claim 1 , wherein a plurality of said surface features have a triangular cross-section.

11 . The method of claim 1 , wherein a plurality of surface features are asymmetric.

12 . The method of claim 1 , wherein a plurality of surface features are symmetric.

13 . The method of claim 1 , wherein the plurality of surface features have an average height in a range from 10 to 500 nanometers high.

14 . The method of claim 1 , wherein the plurality of surface features have an average peak-to-peak spacing in a range from 100 to 500.

15 . The method of claim 1 , wherein the plurality of surface features have an average full width at half maximum (FWHM) in a range from 75 to 250 nm.

16 . The method of claim 1 , wherein the substrate is cut by the laser such that the plurality of surface features extends out, on one or both of the top and bottom major surfaces no more than 2 mm from the path cut by the laser.

17 . The method of claim 1 , wherein the substrate is cut by the laser such that the plurality of surface features extends out, on one or both of the top and bottom major surfaces no more than 1.8 mm from the path cut by the laser.

18 . The method of claim 1 , wherein the substrate is cut by the laser such that the plurality of surface features extends out, on one or both of the top and bottom major surfaces no more than 1.6 mm from the path cut by the laser.

19 . The method of claim 1 , wherein the substrate is cut by the laser such that the plurality of surface features extends to at least within 0.2 mm from said path cut by the laser.

20 . The method of claim 1 , wherein the substrate is cut by the laser such that the plurality of surface features extends to at least within 0.1 mm from said path cut by the laser.

21 . The method of claim 1 , wherein the substrate is cut by the laser such that the plurality of surface features extends to at least within 0.05 mm from said path cut by the laser.

22 . The method of claim 1 , further comprising depositing light absorbing material on the edge and one or more of plurality of surface features.

23 . The method of claim 22 , further comprising covering an area beyond portions of the top and bottom major surfaces having the plurality of surface features with the light absorbing material.

24 . The method of claim 1 , wherein said plurality of surface features are not covered by dark material.

25 . The method of claim 1 , wherein said plurality of surface features are not covered by black or grey material.

26 . The method of claim 1 , wherein said plurality of surface features are not covered by opaque material.

27 . The method of claim 1 , wherein the waveguide is included as part of a stack of waveguides.

28 . The method of claim 1 , wherein the eyepiece is disposed on a frame configured to be supported on the head or face of the user.

29 . The method of claim 1 , wherein the eyepiece is included in eyewear configured to be worn by the user.

30 . The method of claim 1 , wherein the eyepiece is transparent such that the user can see through the eyepiece to view the environment in front of the user and the eyepiece.

31 . The method of claim 1 , wherein said laser beam cuts along an edge of said plurality of surface features.

32 . The method of claim 1 , wherein said laser beam cuts along a path surrounded on both sides by a plurality of said surface features.

33 . The method of claim 1 , wherein said laser beam cuts along a path surrounding said plurality of surface features such that said plurality of surface features are disposed between said path and said main region.

34 . A display system configured to be disposed on a user's head and/or face so as to present images to a user's eye, said display system comprising:
at least one light source configured to produce light;
an eyepiece configured to direct light from said light source to a user's eye to display image content therein, said eyepiece comprising:
at least one waveguide having top and bottom major surfaces and an edge extending therebetween, said waveguide having a main region and a peripheral region surrounding said main region, said peripheral region more proximal to said edge than said main region, said waveguide configured to propagate light from said at least one light source between said top and bottom major surfaces by total internal reflection and eject at least some of said light out of at least a portion of said main region of said waveguide to said user's eye to present image content thereto, and a plurality of surface features within said peripheral region of said waveguide configured to couple light propagating in said waveguide out of said waveguide out from said peripheral region, said surface features having one or more parameters that changes with distance from said edge closest thereto.

35 . The display system of claim 34 , wherein the plurality of surface features comprises a diffractive optical element.

36 . The display system of claim 34 , wherein the plurality of surface features comprises a diffraction grating.

37 . The display system of claim 34 , wherein the plurality of surface features comprises a blazed grating.

38 . The display system of claim 34 , wherein at least one of said surface features has at least one sloping surface.

39 . The display system of claim 34 , wherein at least one of said surface features has two sloping surfaces.

40 . The display system of claim 34 , wherein a plurality of said surface features have a sawtooth shape.

41 . The display system of claim 34 , wherein a plurality of said surface feat

Assignees

• Magic Leap Inc

Inventors

• Varghese Benjamin Lawrence
• Sawicki Joseph Christopher

Classifications

• G02B27/0172

  characterised by optical features · CPC title

• G02B6/0065

  Manufacturing aspects; Material aspects · CPC title

• G02B6/0036

  2-D arrangement of prisms, protrusions, indentations or roughened surfaces · CPC title

• G02B5/1852

  using mechanical means, e.g. ruling with diamond tool, moulding · CPC title

• G02B2027/0109

  comprising details concerning the making of holograms · CPC title