# US 12,222,507 B2 · Optical waveguide structure, AR device, and method for obtaining emergent light efficiency of optical waveguide structure

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- Number: US 12,222,507 B2
- Document ID: US12222507B2
- Status: Granted
- Kind: B2
- Application number: 17/790,000
- Filed: 2021-09-01
- Published: 2024-06-06
- Granted: 2025-02-11
- Earliest claimed: 2021-09-01
- Assignees: Beijing Boe Display Technology Co., Ltd.; Boe Technology Group Co., Ltd.
- Applicants: Beijing BOE Display Technology Co., Ltd.; BOE Technology Group Co., Ltd.
- Inventors: Na Han; Chenru Wang; Ruijun Dong; Yulong Wu; Ke Li; Jiarong Bai; Zhanshan Ma; Haitao Huang
- Web page: https://patentgrep.com/patent/US12222507B2

## CPC

- G02B 27/0172: {characterised by optical features}
- G02B 5/1819: {Plural gratings positioned on the same surface, e.g. array of gratings (plural diffractive elements positioned sequentially along the optical path G02B27/4272)}
- G02B 6/00: Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B 6/34: utilising prism or grating {(G02B6/293 takes precedence)}
- G02B 27/01: Head-up displays
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

Provided are an optical waveguide structure, an Augmented Reality (AR) device, and a method for obtaining an emergent light efficiency of an optical waveguide structure, which relates to the technical field of display. The optical waveguide structure includes: an optical waveguide body, a coupling-in grating disposed at the optical waveguide body, and a plurality of coupling-out gratings distributed and arranged. The coupling-in grating is configured to couple image light into the optical waveguide body. The optical waveguide body is configured to generate a total internal reflection of the image light to the coupling-out gratings. Diffraction efficiencies of each of the coupling-out gratings are different, and each of the coupling-out gratings is configured to couple the image light out of the optical waveguide body at the same brightness.

## Claims

### Claim 1

A method for obtaining an emergent light efficiency of an optical waveguide structure, comprising:
obtaining a diffraction efficiency and a reflection efficiency of each of coupling-out gratings in the optical waveguide structure; and
obtaining an emergent light efficiency of the optical waveguide structure according to the diffraction efficiency and the reflection efficiency;
obtaining the emergent light efficiency of the optical waveguide structure according to the diffraction efficiency and the reflection efficiency comprises:
obtaining the emergent light efficiency of the optical waveguide structure according to the following formula:
η
=
∑
n
-
1
N
(
R
n
-
1
×
R
n
-
2
⁢
…
⁢
R
0
)
×
T
n
⁢
R
n
=
1
-
T
n
wherein η represents the emergent light efficiency, n represents number of coupling-out gratings, N represents total number of coupling-out grating partitions, Rn-1 represents the reflection efficiency of the (n−1)th coupling-out grating, and Tn represents the diffraction efficiency of the nth coupling-out grating;
obtaining the diffraction efficiency of each of the coupling-out gratings in the optical waveguide structure according to the following formula:
Tn=(N−n+1)−1
wherein Tn represents the diffraction efficiency of the nth coupling-out grating, n represents the number of coupling-out gratings, and N represents the total number of coupling-out grating partitions.