Optical waveguide structure, AR device, and method for obtaining emergent light efficiency of optical waveguide structure
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.
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, R n-1 represents the reflection efficiency of the (n−1) th coupling-out grating, and T n represents the diffraction efficiency of the n th coupling-out grating;
obtaining the diffraction efficiency of each of the coupling-out gratings in the optical waveguide structure according to the following formula:
T n =( N−n+ 1) −1
wherein T n represents the diffraction efficiency of the n th coupling-out grating, n represents the number of coupling-out gratings, and N represents the total number of coupling-out grating partitions.