分孔径红外偏振成像仪光学系统设计

为了在复杂及伪装的红外背景中识别出小温差目标,本文提出了一种基于分孔径的偏振成像系统结构,并对分孔径偏振成像系统所采用的分孔径成像系统及中继成像系统进行了设计研究。首先,根据Stokes矢量介绍了系统的工作理论和光学结构;其次,在现有探测器的结构参数要求下,计算出了光学系统的偏心量等参数,选择硅、锗作为透镜材料。在此基础上,确定了分孔径成像系统结构和中继成像系统结构。接着使用离轴偏心多重结构设计方法对初始结构进行了优化,研究了将普通红外物镜转变为具有实入瞳的像方远心结构的方法;最后,完成了分孔径成像系统和中继成像系统的整体系统匹配。设计结果表明,整体系统的调制传递函数在探测器奈奎斯特频率为17 lp/mm处大于0.6,能够满足系统的设计要求。本文设计的结构可以对探测目标实现实时偏振成像,且具有结构紧凑的优点。

Design of decentered aperture-divided optical system of infrared polarization imager

In order to identify the target with little temperature difference in complicated and disguised infrared background, a decentered aperture-divided polarization imaging system is introduced in this paper. The design of decentered aperture-divided imaging system and relay imaging system adopted in decentered aperture-divided polarization imaging system are also studied. Firstly, the working theory and optical structure of the system are introduced according to the Stokes vectors. Secondly, the parameters of the optical system such as the eccentricity are calculated under the requirements of the structural parameters of the existing detectors in the laboratory, and silicon and germanium are selected as the lens materials. According to these parameters, both the structure of aperture-divided imaging system and that of relay imaging system are determined on this basis. Then the off-axis eccentric multi-structure design method is used to optimize the initial structure. The transformation method from ordinary infrared objective to image-side telecentric structure with real entrance pupil is studied. Finally, the overall system matching of aperture-divided imaging system and relay imaging system is completed. The results show that the overall system modulation transfer function(MTF) at Nyquist frequency of the detector of 17 lp/mm is greater than 0.6, which can meet the system design requirements. The structure introduced in this paper can detect the real-time polarization of the target, and possesses the advantages of compact structure.