30×制冷型中波消热差红外变焦光学系统设计

摘要

On the basis of cooled staring focal plane array (FPA) detectors with 640×512 pixel and 20μm pix⁃el elements, a mid-infrared continuous zoom optical system with 30 zoom ratio is designed. Operation waveband of the system is 3.7~4.8μm, F number is 3.7 and focal length range is from 11.64 to 349.2 mm. The system includes two parts such as a zoom system and a re-imaging system, which includes 12 lenses. Main function of the re-imag⁃ing system is to realize 100%cooled diaphragm efficiency and reduce radial size of optical systems. Space resolu⁃tion of the system can be 21 lp/mm and the energy concentration rate is above 75%in 25μm. And imaging quality of the system is much better. Optical passive athermal design is realized in the range of-40~+60℃.%　　针对像素为640×512、探测器的像元尺寸为20μm的制冷型凝视焦平面阵列探测器,设计了变倍比为30的中波红外连续变焦光学系统.系统工作波段为3.7~4.8μm,F数为3.7,焦距变化范围为11.64~349.2 mm.系统由两部分组成：变焦系统和二次成像系统,共12片透镜.其中,二次成像系统的主要作用是实现100%冷光阑效率的同时,减小光学系统的径向尺寸.系统的空间分辨率达到21 lp/mm,在25μm内能量集中在75%以上,系统成像质量较好,在-40~+60℃的温度范围内实现了光学被动式消热差的设计.