基于双图像生成器的双焦面抬头显示系统光学设计

Optical Design of Dual-Focal-Plane Head-Up Display Based on Dual Picture Generation Units

增强现实型抬头显示器拥有比传统抬头显示器更加丰富的显示内容。理想的增强现实型抬头显示器需要显示多个不同深度的虚像来呈现基础与交互信息,但传统的解决方案多为通过高速旋转反射镜或光学变焦系统来显示两种深度的内容,可靠性较低,存在驾驶安全隐患。提出了一种采用两块图像生成单元和单块自由曲面镜实现双焦面显示的离轴反射式光学结构,通过添加一块平面反射镜增加远场光路物距,从而实现双焦面的显示,最终得到一个视野盒大小为130 mm×50 mm、视场角分别为5°×1°和10°×5°、虚像距离分别为2.5 m和7.5 m的双焦面抬头显示器系统。该研究结果不仅满足了近场基础信息与远场交互信息同时显示的需求,景深的显示效果也同样得到了改善。

Compared with conventional head-up displays(HUDs),augmented reality HUDs(AR-HUDs)can display richer information,and an ideal AR-HUD requires the display of multiple virtual images at different depths to present basic and interactive information.In most traditional solutions,however,the display of information at the two depths is achieved by rotating the reflective mirror at high speed or using the optical zoom system,with lower reliability and potential safety hazards.Therefore,the optical off-axis reflective structure is proposed to achieve the dual-focal-plane display using two picture generation units(PGUs)and a single free-from surface mirror.By adding a plane mirror to increase the object distance of the far-field optical path,we achieve a display of two focal planes.Finally,a dual-focalplane HUD is obtained,with an eye box of 130 mm×50 mm,field-of-view angles of 5°×1°and 10°×5°,and virtual image distances(VIDs)of 2.5 m and 7.5 m.The research results meet the requirement of the simultaneous display of nearfield basic information and far-field interactive information,and the display effects of depth of field are enhanced.