基于谐衍射与自由曲面的机载红外双波段成像光学系统设计

Design of Airborne Infrared Dual-band Imaging Optical System Based on Harmonic Diffraction and Free-form Surface

为实现对远距离红外辐射目标的探测、识别,通过对谐衍射、自由曲面以及离轴三反光学系统的模型及理论进行分析,提出一种基于谐衍射和自由曲面的离轴三反双波段红外成像光学系统。量化指标实例分析选择初始结构,使用Zemax宏语言控制优化过程,设计了一种焦距1200 mm,口径300 mm的双波段(3~5μm、8~12μm)红外成像光学系统。系统在空间频率10 lp/mm处,3~5μm波段调制传递函数大于0.6,8~12μm波段调制传递函数大于0.45,双波段全视场弥散斑半径均方根小于25μm。系统在-60℃~+60℃工作温度范围内实现非热敏化。该系统结构简单,设计结果满足各项任务指标,具有较高的可实现性,对机载双波段红外成像光学系统的进一步研制具有重要意义。

In order to realize the detection,identification of long-distance infrared radiation targets.Through the research and analysis of the model and theory of harmonic diffraction,free-form surface and off-axis three-mirror optical system,we propose a design scheme of off-axis triple-mirror dual-band infrared imaging optical system based on harmonic diffraction and free-form surface.By selecting the initial structure through the analysis of quantitative indicators and using Zemax macro language to control the process of system optimization,a dual-band(3~5μm,8~12μm)infrared imaging optical system with a focal length of 1200 mm and a diameter of 300 mm was designed.When the system is at a spatial frequency of 10 lp/mm,the value of the modulation transfer function in the 3~5μm band is greater than 0.6,and the value of the modulation transfer function in the 8~12μm band is greater than 0.45.The root-mean-square radius of the diffuse spot of the system's dual-band full field of view is less than 25μm.The system realizes non-thermal sensitization in the working temperature range of-60℃~+60℃.The designed system not only has a simple structure,meets the requirements of various technical indicators,but also has high realizability,which is of great significance to the further development of the airborne dual-band infrared imaging optical system.