紧凑型离轴三反光学系统的自由曲面设计

Design of Freeform Surface in Compact,Off-Axis,Three-Mirror System

光学加工和检测技术的提高为自由曲面的应用开拓了新的领域,紧扣空间光学对压缩系统体积和实现系统性能提升的需求,提出一种可快速获得的紧凑型离轴三反光学系统初始结构,通过3个镜面折叠交叉排布,极大地压缩了系统体积;另外,节点像差理论为自由曲面应用提供了强大的理论基础,在优化过程中,两片镜子采用了泽尼克多项式面形。通过设计实例验证发现,最终系统具有结构紧凑、大视场、小F数等优点,同时该设计方法的优化过程具有收敛速度快等特点。

The technological advancement in optical fabrication and testing has exploited a new field for the application of freeform surfaces.Based on the requirements of volume compression and performance promotion for space optics,an initial configuration of a compact,off-axis,three-mirror optical system is presented.The three mirrors are folded,which greatly compresses the volume.In addition,since the nodal aberration theory has laid a theoretical foundation for the application of freeform surfaces,two Zernike polynomial surfaces are adopted in the optimization process.With the verification of a designed example,it can be found that the final optical system possesses the advantages of compact structure,wide field-of-view and small F number,while the optimization process based on this design method can converge to the expected result with a fast speed.