Waveguides having integrated spacers, waveguides having edge absorbers, and methods for making the same

Patent metadata

Field	Value
Publication number	US-11886000-B2
Application number	US-201917044754-A
Country	US
Kind code	B2
Filing date	Apr 1, 2019
Priority date	Apr 2, 2018
Publication date	Jan 30, 2024
Grant date	Jan 30, 2024

Abstract

In some embodiments, a head-mounted, near-eye display system comprises a stack of waveguides having integral spacers separating the waveguides. The waveguides may each include diffractive optical elements that are formed simultaneously with the spacers by imprinting. The spacers are disposed on one major surface of each of the waveguides and indentations are provided on an opposite major surface of each of the waveguides. The indentations are sized and positioned to align with the spacers, thereby forming a self-aligned stack of waveguides. Tops of the spacers may be provided with light scattering features, anti-reflective coatings, and/or light absorbing adhesive to prevent light leakage between the waveguides. As seen in a top-down view, the spacers may be elongated along the same axis as the diffractive optical elements. The waveguides may include structures (e.g., layers of light absorbing materials, rough surfaces, light out-coupling optical elements, and/or light trapping microstructures) along their edges to mitigate reflections and improve the display contrast.

First claim

What is claimed is:

1. A display system comprising:
an eyepiece comprising a stack of waveguides, wherein the stack of waveguides comprises:
at least one waveguide comprising:
an optically transmissive body comprising:
diffractive optical elements comprising a plurality of protrusions and intervening recesses on a major surface of the optically transmissive body;
spacers integral with the optically transmissive body and comprising a pattern of light scattering features on tops of the spacers, wherein the spacers extend to a height greater than a height of the diffractive optical elements; and

an overlying waveguide disposed on the spacers,
wherein the spacers separate the optically transmissive body from the overlying waveguide by a gap.

2. The display system of claim 1 , wherein the overlying waveguide comprises indentations accommodating the spacers in the indentations.

3. The display system of claim 2 , wherein each waveguide of the stack of waveguides comprises a respective portion of the spacers and indentations, wherein the indentations accommodate the respective portion of the spacers of underlying waveguides.

4. The display system of claim 2 , wherein the spacers comprise multiple tiers having progressively narrower widths with increasing height, wherein the indentations comprise openings having multiple tiers with narrower widths as height increases.

5. The display system of claim 1 , wherein sizes of the spacers vary across the major surface.

6. The display system of claim 5 , wherein the spacers are arranged in groups, wherein neighboring spacers of a group have different sizes.

7. The display system of claim 1 , wherein, as seen in a top-down view, the spacers comprise one or more shapes selected from the group consisting of rectangular prism, rectangular pyramid, triangular prism, triangular pyramid, cylinder, and cone.

8. The display system of claim 1 , further comprising an adhesive attaching the spacers to the overlying waveguide.

9. The display system of claim 8 , wherein the adhesive is configured to absorb light.

10. The display system of claim 1 , wherein the overlying waveguide comprises the diffractive optical elements configured to redirect light of different wavelengths than to the diffractive optical elements of the at least one of the waveguides.

11. The display system of claim 1 , wherein the gap is an air gap.

12. A display system comprising:
an eyepiece comprising a waveguide comprising:
an optically transmissive body comprising:
diffractive optical elements comprising a plurality of protrusions and intervening recesses on a major surface of the optically transmissive body; and
spacers integral with the optically transmissive body, wherein the spacers extend from the major surface to a height greater than a height of the diffractive optical elements, and
a pattern of light scattering features on tops of the spacers.

13. A method for making an eyepiece, the method comprising:
forming a waveguide, wherein forming the waveguide comprises:
defining integral diffractive optical elements and integral spacers on a major surface of the waveguide, wherein the integral spacers are spaced-apart from the integral diffractive optical elements and extend to a height above the integral diffractive optical elements, wherein defining the integral diffractive optical elements and the integral spacers comprises a pattern of light scattering features on tops of the spacers.

14. The method of claim 13 , wherein defining integral diffractive optical elements and the integral spacers comprises forming the integral diffractive optical elements and the integral spacers simultaneously.

15. The method of claim 13 , wherein defining integral diffractive optical elements and the integral spacers comprises:
providing an upper imprint mold and a lower imprint melds mold, wherein the imprint molds face one another;
providing a flowable material on the lower imprint mold;
contacting the flowable material with the upper imprint mold;
subjecting the flowable material to a hardening process, to generate a hardened flowable material, wherein the hardened flowable material forms the waveguide; and
removing the upper and lower imprint molds from the waveguide.

16. The method of claim 15 , wherein the upper imprint mold comprises a pattern of protrusions and indentations, wherein contacting the flowable material with the upper imprint mold transfers a corresponding pattern of protrusions and indentations into the flowable material to imprint the integral diffractive optical elements and the integral spacers in the flowable material.

17. The method of claim 15 , further comprising, after subjecting the flowable material to the hardening process:
removing the upper imprint mold;
depositing another flowable material on the hardened flowable material; and
contacting the another flowable material with another upper imprint mold, wherein the another upper imprint mold comprises a pattern of protrusions and indentations, and contacting the another flowable material with the another upper imprint mold transfers a corresponding pattern of protrusions and indentations into the another flowable material to imprint the integral diffractive optical elements and the integral spacers in the another flowable material.

18. The method of claim 15 , wherein, as seen in a top-down view, the integral diffractive optical elements comprise a diffractive grating comprising a plurality of protrusions elongated along an axis, wherein the integral spacers are elongated and have a length extending along the axis.

19. The method of claim 13 , further comprising stacking another waveguide on the integral spacers, wherein the integral spacers support the another waveguide and define a gap between the waveguide and the another waveguide.

Assignees

• Magic Leap Inc

Inventors

• Peroz Christophe
• Chang Chieh
• Bhagat Sharad D
• LIU Victor Kai
• Patterson Roy Matthew
• Jurbergs David Carl
• Khorasaninejad Mohammadreza
• Li Ling
• Miller Michael Nevin
• Carden Charles Scott

Classifications

• G02B6/0088 Primary

  of the light guide or other optical sheets in the package · CPC title

• B29D11/00673

  Supports for light guides · CPC title

• G02B6/0016

  Grooves, prisms, gratings, scattering particles or rough surfaces · CPC title

• G02B6/0036

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

• G02B6/0076

  Stacked arrangements of multiple light guides of the same or different cross-sectional area · CPC title