【摘要】 增强现实（augmented reality,AR）系统是一种将虚拟影像叠加到现实环境的显示系统，光波导是AR显示系统的核心元件，可以实现系统的微型化与轻量化。光波导耦合元件衍射效率的高低极大地影响AR显示系统的成像质量，为提高AR显示系统中耦合元件的衍射效率，该文提出了一种多层光栅叠加的波导结构，基于矢量衍射理论，采用严格耦合波分析法对光栅进行仿真分析。仿真结果显示：单层倾斜光栅的平均衍射效率在50°视场角范围内达到60%,3层光栅叠加的波导结构平均衍射效率达到85%以上，较单层光栅衍射效率提高了25%。分析结果表明，多层光栅叠加的波导结构可以实现更大的视场角与衍射效率，使AR显示系统具有更清晰的视场。更多还原

【Abstract】 Augmented reality(AR) system is a display system that superimposes virtual images on the real environment. Since the optical waveguide can realize miniaturization and light weight, it is the core component of the AR display system. The diffraction efficiency of the optical waveguide coupling element greatly affects the imaging quality of the AR display system. In order to improve the diffraction efficiency of the coupling element in the AR display system, a waveguide structure with multi-layer superimposed gratings was proposed. Based on the vector diffraction theory, the grating was simulated and analyzed by using the rigorous coupled wave analysis method. Simulation results show that the average diffraction efficiency of a single-layer inclined grating reaches 60% at a field of view of 50°, and the average diffraction efficiency of a waveguide structure with three layers of superimposed gratings reaches more than 85%, which is 25% higher than that of a single-layer grating. The analysis results show that the waveguide structure with multi-layer superimposed gratings can achieve a larger field of view and diffraction efficiency, so that the AR display system has a clearer viewing field.更多还原