一种双波段成像系统的红外通道杂散光分析

摘要

为全面分析杂散光对红外系统成像质量的影响,设计了可见波段0.4μm～0.7μm、红外波段3 μm～5μm,视场角均为2.27°×2.27°的共孔径成像光学系统.分析了杂散光来源,分别研究了带内与带外杂散光对其红外通道成像质量的影响.对于带内杂散光,设计了消杂光结构,采用FRED软件模拟分析了带内杂光抑制能力,结果表明:带内杂散光得到较好抑制,其鬼像影响可忽略不计,太阳杂散光抑制水平PST达到设定的10-8阈值量级.对于带外杂散光,主要研究了1.064 μm和2.6 μm两个波长带外激光对红外成像系统的影响,并利用有限元仿真计算,结果表明:系统反射镜温升达到703 K时,向外发出较强带内红外辐射,到达像面的辐射功率为0.195mW,可对红外成像面造成强烈噪声干扰.%To analyze the effect of stray light on infrared imaging system comprehensively,a common aperture imaging optical system was designed for both visible band(0.4μm～0.7 μm)and infrared band(3 μm～5 μm) while the field of view is 2.27°×2.27°.By analyzing the stray light source,the effect of in-band stray light and off-band stray light on imaging quality of infrared channel was studied respectively.The structure of the hybrid light was designed for in-band stray light and the suppression capability was simulated and analyzed by FRED optical software.According to the result,the in-band stray light can be suppressed well,the ghost impact is negligible,and the point sources transmittance (PST) of solar stray light suppression level reaches the set threshold level of 10-8.For off-band stray light,the influence of 1.064 μm and 2.6 μm infrared laser on infrared imaging system was mainly studied by finite element method.Results show that the in-band infrared radiation can be generated strong when the temperature of system mirror rises to 703 K and the radiation power to the image plane reaches 0.069 mW,which can cause strong noise interference on the infrared imaging surface.