US 12,436,385 B2
Diffractive optical waveguide, design method for diffractive optical waveguide, and display device
Yuming Song, Tongxiang (CN); Lei Sui, Tongxiang (CN); and Kehan Tian, Tongxiang (CN)
Assigned to Jiaxing UPhoton Optoelectronics Technology Co., Ltd., (CN)
Appl. No. 18/994,703
Filed by JIAXING UPHOTON OPTOELECTRONICS TECHNOLOGY CO., LTD., Tongxiang (CN)
PCT Filed Mar. 15, 2024, PCT No. PCT/CN2024/081990
§ 371(c)(1), (2) Date Jan. 15, 2025,
PCT Pub. No. WO2024/188346, PCT Pub. Date Sep. 19, 2024.
Claims priority of application No. 202310281767.5 (CN), filed on Mar. 16, 2023.
Prior Publication US 2025/0264718 A1, Aug. 21, 2025
Int. Cl. G02B 27/00 (2006.01); G02B 27/01 (2006.01); G02B 27/42 (2006.01)
CPC G02B 27/0081 (2013.01) [G02B 27/0012 (2013.01); G02B 27/0172 (2013.01); G02B 27/4205 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A diffractive optical waveguide for optical pupil expansion, comprising:
a waveguide substrate comprising a coupling-in region;
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 input light to propagate within the waveguide substrate through total reflection;
wherein the coupling-in grating comprises a plurality of coupling-in grating blocks arranged randomly and continuously, the plurality of coupling-in grating blocks have the same period, and at least two coupling-in grating blocks of the plurality of coupling-in grating blocks have different duty cycles, wherein,
a first coupling-in grating block of the at least two coupling-in grating blocks comprises a plurality of grating units, and each grating unit of the first coupling-in grating block has a first duty cycle,
a second coupling-in grating block of the at least two coupling-in grating blocks comprises a plurality of grating units, and each grating unit of the second coupling-in grating block has a second duty cycle,
the first duty cycle is different from the second duty cycle;
wherein in a first direction, a duty cycle of at least one third coupling-in grating block of the plurality of coupling-in grating blocks is greater than duty cycles of two coupling-in grating blocks adjacent to the at least one third coupling-in grating block along the first direction, and the third coupling-in grating block is located between the first coupling-in grating block and the second coupling-in grating block; and/or
in a second direction, a duty cycle of at least one fourth coupling-in grating block of the plurality of coupling-in grating blocks is smaller than duty cycles of two coupling-in grating blocks adjacent to the at least one fourth coupling-in grating block along the second direction, and the fourth coupling-in grating block is located between the first coupling-in grating block and the second coupling-in grating block.