杂散光抑制能力是光学系统的重要评价指标.红外光学系统不仅受到外部杂散光影响, 而且受到仪器内部杂散光影响.传统的“物-像”共轭光学系统的设计方法未能全面考虑杂散光的抑制问题.提出一种三重共轭光学系统的设计方法, 该方法设计出的光学系统具有“物-像”、“物-中间像”和“入瞳-出瞳”三重共轭关系, 具有同时抑制内部和外部杂散光的能力.基于该方法设计出一种离轴三反射式消像散光学系统, 该系统F/#=4、一维线视场7°, 离轴5度视场外点源透过率低于5×10-4, 系统冷屏效率达到96%, 并获得良好的在轨图像.

Stray light control is an important technical indicator of an optical system’s performance. The stray light in infrared optical systems includes not only external stray light, but also the internal radiation stray light. The conventional initial system design method limited to an “object-image" conjugate relationship cannot properly take account of stray light. This paper presents a triple conjugate optical system design method for “object-image”, “object-intermediate real image” and “entrance pupil-exit pupil” triple conjugate relationships that minimizes the influences of internal and external stray light to provide good stray light control performance. With this method, an off-axis three-mirror anastigmatic infrared optical system with F/# = 4, linear field of view = 7°, point source transmission less than 5×10-4, and cold iris efficiency 96% was designed and imaged good pictures in orbit.