Method of conical anisotropic rigorous coupled wave analysis for grating and computing device

Patent metadata

Field	Value
Publication number	US-12320989-B2
Application number	US-202217666717-A
Country	US
Kind code	B2
Filing date	Feb 8, 2022
Priority date	Feb 8, 2022
Publication date	Jun 3, 2025
Grant date	Jun 3, 2025

Abstract

A method of conical anisotropic rigorous coupled wave analysis for grating and a computing device are disclosed. The method includes: obtaining a target geometric phase δ′ g for the anisotropic-material-based grating; obtaining a slow axis azimuth angle ϕ c (x) of the anisotropic-material-based grating according to the target geometric phase δ′ g ; obtaining a permittivity tensor of the anisotropic-material-based grating, wherein the anisotropic-material-based grating has an ordinary index n o and an extraordinary index n e , the anisotropic-material-based grating has a slow axis polar angle θ c and slow axis azimuth angle ϕ c (x), and the permittivity tensor is based on n o , n e , θ c and ϕ c (x); applying the permittivity tensor into Maxwell equations; obtaining electromagnetic field for the anisotropic-material-based grating by using boundary conditions of at least two layers or sublayers of the anisotropic-material-based grating to obtain a diffraction efficiency for the anisotropic-material-based grating.

First claim

What is claimed is:

1. A method of obtaining a diffraction efficiency of an anisotropic-material-based grating having at least two layers or sublayers in augmented reality (AR)/virtual reality (VR) devices, comprising:
obtaining, by a processor, a target geometric phase δ′ g for the anisotropic-material-based grating;
obtaining, by the processor, a slow axis azimuth angle ϕ c (x) of the anisotropic-material-based grating according to the target geometric phase δ′ g ;
obtaining, by the processor, a permittivity tensor of the anisotropic-material-based grating, wherein the anisotropic-material-based grating has an ordinary index n, and an extraordinary index ne, the anisotropic-material-based grating has a slow axis polar angle θ c and slow axis azimuth angle ϕ c (x), and the permittivity tensor is based on n o , n e , θ c and ϕ c (x);
applying, by the processor, the permittivity tensor into Maxwell equations;
obtaining, by the processor, electromagnetic field for the anisotropic-material-based grating by using boundary conditions of the at least two layers or sublayers of the anisotropic-material-based grating and Maxwell equations for each layer or sublayer, to obtain the diffraction efficiency for the anisotropic-material-based grating,
determining if the at least two layers or sublayers are suitable to be integrated into one stack for an output coupler grating or an input coupler grating of a waveguide in the augmented reality/virtual reality devices based on the diffraction efficiency; and
analysing the diffraction efficiency by a color dispersion and light control within the augmented reality/virtual reality devices.

2. The method according to claim 1 , wherein obtaining electromagnetic field for the anisotropic-material-based grating by using boundary conditions of the at least two layers or sublayers of the anisotropic-material-based grating and Maxwell equations for each layer or sublayer further includes:
obtaining a matrix F 1 for a first layer or sublayer of the anisotropic-material-based grating by using a first boundary condition between the first layer or sublayer and a region 1 through a first equation as below:

[

sin
⁢
ψ
⁢

δ

i
⁢
0

j
⁢
sin
⁢
ψ
⁢

n
1

⁢
cos
⁢
θ
⁢

δ

i
⁢
0

-
j

⁢
cos
⁢
ψ
⁢

n
1

⁢

δ

i
⁢
0

cos
⁢
ψ
⁢
cos
⁢
θ
⁢

δ

i
⁢
0

]

+

[

I

0

-
j

⁢

Y
I

0

0

I

0

-
j

⁢

Z
I

]

[

R
s

R
p

]

=

F
1

·
C

obtaining a matrix F L for a final layer or sublayer of the anisotropic-material-based grating by using a last boundary condition between the final layer or sublayer and a region 3 through a second equation as below:

F
L

Assignees

• Goertek Inc

Inventors

• Li Lingshan

Classifications

• G02B27/0101 Primary

  characterised by optical features (G02B27/0172 takes precedence) · CPC title

• G02B5/1814

  structurally combined with one or more further optical elements, e.g. lenses, mirrors, prisms or other diffraction gratings (G02B5/189 takes precedence) · CPC title

• G02B5/1842

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

• G02B27/0172

  characterised by optical features · CPC title

• G06F17/11

  for solving equations {, e.g. nonlinear equations, general mathematical optimization problems (optimization specially adapted for a specific administrative, business or logistic context G06Q10/04)} · CPC title