Optical waveguide structure, AR device, and method for obtaining emergent light efficiency of optical waveguide structure

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.