自由曲面棱镜是轻型头盔显示系统的核心光学器件, 其巧妙的设计以及精密的加工方法历来备受研究者的关注。目前有关自由曲面棱镜的研究主要集中于视场角和成像质量上, 而忽略了公差设计, 尤其是加工误差对棱镜的影响。针对这一现象, 在详细分析了自由曲面棱镜的加工误差来源之后, 提出了基于公差约束的自由曲面棱镜优化设计方法, 以保证在加工精度允许的前提下得到最佳的成像质量。通过光学仿真实验及成像质量分析, 验证了该方法的有效性。

Free-form prism is the core optical element of the light system for head-mounted display, and its smart design and precise processing have attracted the researchers’ attention. At present, the researches in free-form prism have focused on the view angle and imaging quality of prism, and ignored the tolerance of design especially the influence of error produced in the prism’s processing. A detailed analysis is conducted for the error sources, which produced in free-form prism processing, and a prism design method is put forward according to the requirements of processing tolerance. This method guarantees the machining accuracy allowed in the premise, and gets the best prism image quality. Through the optical simulation and imaging quality analysis, the effectiveness of the proposed method is verified.