基于双DMD的红外场景投影仪光学系统设计

Design of optical systems for infrared scene projector based on dual-DMD

为提高中波红外场景投影仪的帧速和灰度等级,提出了一种基于双数字微反射镜器件(DMD)的光学系统方案。该光学系统包括照明系统和准直投影光学系统,照明系统采用可提供均匀照明的柯勒照明系统,利用2个非球面透镜简化结构,采用3片式全内反(TIR)棱镜来实现光路的折转衔接以及2个DMD调制的叠加;准直投影光学系统采用二次成像结构,通过合理分配各透镜组光学参数,并采用非球面透镜进行优化设计,得到的光学系统F数为0.94,入瞳距为850 mm,角分辨率为0.19 mrad。投影仪的测试与仿真结果表明此光学系统完全满足红外场景投影仪的使用要求。

In order to improve the frame rate and the grey level of the midwave(MWIR)infrared scene projector,the optical systems scheme based on dual-DMD(Digital micro-mirror device)is presented.The optical systems include the illumination system and the collimating projection optics.The Kohler illumination is used to supply uniform illumination for the projector.The two aspheric lenses are used to simplify configuration of the illumination system.The TIR prism containing three-sections are used to fold and connect the ray path of the illumination system and the collimating projection optics,meanwhile superposing the modulation of the two DMD.The collimating projection optics uses a re-imaging configuration.The optimization of the collimating projection optics is accomplished by distributing the parameters of the lenses and using aspheric surfaces in the lenses.The F/number of the collimating projection optics is 0.94.The entrance pupil distance is 850 mm.The angular resolution is 0.19 mrad.The results of the testing and simulation for the projector illustrate that the performances of the optical systems meet the requirements of the infrared scene projector.