基于自由曲面的大视场离轴四反光学系统设计

摘要

反射系统具有体积小、重量轻、无色差、成像性能优良等特点，广泛应用于航空机载领域。本文基于矩阵光学理论，并以此建立非线性方程组，用数学软件求解得到满足要求的初始结构。优化过程中不断调整系统各镜的偏心和倾斜，消除系统的中心遮拦。在光学系统中引入自由曲面，提升了光学系统的轴外像差平衡能力，增大系统视场角。设计了焦距100 mm，视场角20°×20°，相对孔径为 F／7的离轴四反射镜光学系统。结果表明，该光学系统具有较大的成像视场，结构紧凑，无中心遮拦，成像质量接近衍射极限。%Reflective optical systems have small size,lightweight,and excellent imaging performance,which make it very popular in airborne field.A nonlinear equation group was built based on the matrix optics theory,the initial con-struction parameters of the optical system can be obtained by deriving this equation group.And during the design process,decenters and tilts of mirrors were adjusted continuously to eliminate the obscurations.the free-form surface was introduced to improve the balance capacity of optical aberration and enhance system field of view.Then an off-ax-is four-mirror optical system with effective focal length of 1 00 mm,FOV of 20°×20°,and relative aperture as F/7 is designed.This system has large imaging field of view,tight structure,acentric obstruction and imaging qualities ap-proaching diffraction limit.