US 11,874,503 B1
Diffractive optical waveguide and display device
Xingming Zhao, Jiaxing (CN); Zhentao Fan, Jiaxing (CN); Qingfeng Zhu, Jiaxing (CN); and Kehan Tian, Jiaxing (CN)
Assigned to JIAXING UPHOTON OPTOELECTRONICS TECHNOLOGY CO., LTD, Jiaxing (CN)
Filed by Jiaxing UPhoton Optoelectronics Technology Co., Ltd., Jiaxing (CN)
Filed on Jul. 3, 2023, as Appl. No. 18/346,410.
Int. Cl. G02B 6/34 (2006.01); G02B 27/00 (2006.01)
CPC G02B 6/34 (2013.01) [G02B 27/0081 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A diffractive optical waveguide for optical pupil expansion, comprising:
a waveguide substrate comprising a coupling-in region and a coupling-out region, wherein the coupling-out region includes a first coupling-out region and a second coupling-out region, and the first coupling-out region and the second coupling-out region are respectively used for corresponding to a left eye and a right eye of human eyes;
a coupling-in grating disposed on or in the waveguide substrate and located in the coupling-in region and configured to couple input light into the waveguide substrate to cause the light to propagate within the waveguide substrate through total reflection, wherein a first diffractive light obtained by the input light diffracted by the coupling-in grating is totally reflected in the waveguide substrate and directed to the first coupling-out region, and a second diffractive light obtained by the input light diffracted by the coupling-in grating is totally reflected in the waveguide substrate and directed to the second coupling-out region;
a coupling-out grating comprising a first coupling-out grating disposed on or in the waveguide substrate and located in the first coupling-out region and a second coupling-out grating disposed on or in the waveguide substrate and located in the second coupling-out region, the first coupling-out grating and the second coupling-out grating both configured to couple at least a portion of light propagating therein out of the waveguide substrate by diffraction, wherein,
the first coupling-out region and the second coupling-out region are respectively located at both sides of the coupling-in region; a center of the coupling-in region deviates from a center line connecting a center of the first coupling-out region and a center of the second coupling-out region, and the center of the coupling-in region is located above a center of the waveguide substrate;
wherein an offset of the center of the coupling-in region relative to the center line satisfies the following formula:

OG Complex Work Unit Math
wherein H is an offset of the center of the coupling-in region relative to the center line; D is a distance between the center of the first coupling-out region and the center of the second coupling-out region; L is a maximum transverse width of the first coupling-out region or the second coupling-out region; W is a maximum longitudinal width of the first coupling-out region or the second coupling-out region; and d is a maximum transverse dimension of the coupling-in region; and wherein
the coupling-in grating as well as the first coupling-out grating and the second coupling-out grating are located on the same side or either side of the waveguide substrate.