新型大视场无遮拦三反光学系统设计

针对传统形式三反光学系统难以实现大视场的缺点，提出了一种基于反摄远结构的三反光学系统，并获得初始结构参数求解方程。在反摄远结构三反光学系统中，将主、次镜组成反转伽利略望远镜结构形式，以便简化三反光学系统初始参数的求解方程，最终通过视场偏置的办法实现无遮拦设计。基于上述方法，采用光学设计软件Code V设计了焦距f=100 mm，F数为5，视场为2020。像质评价结果表明，系统在空间频率为50 lp/mm处的MTF值均大于0.6，像质优良。与其他三反光学系统相比，该系统不仅具有大视场，而且仅使用了两块非球面反射镜，降低了系统成本。

Design of new wide-angle unobscured three-mirror optical system

For the disadvantage of conventional three mirrors system to achieve wide field of view, a new-style unobscured three-mirror optical system with wide field of view was designed based on the retrofocus-type objective configuration. One powerful retrofocus design approach was the combination with a reversed Galilean Telescope, the expression of initial configuration parameters was obtained and the unobscured style was carried out by decenter the field. A system with effective focal length of 100 mm, field of view of 2020 and F-number of 5 was designed, the modulation transfer function value at spatial frequency of 50 lp/mm was over 0.6 and image qualities were excellent. Compared with traditional common three-mirror optical systems, the most prominent advantage of this new three-mirror system are that it can provide wide field of view and just use two aspheric mirrors and one spherical, so that the cost of this system will be reduced.