折/衍混合红外物镜的超宽温消热差设计

Athermalized Design of Extensive Temperature Range for Infrared Hybrid Refractive-Diffractive Objective

为满足红外光学系统高环境适应性和高灵敏度的发展要求,采用折/衍混合结构改进红外3.2～4.2 μm波段,F/#为1.5,视场角为±2.5°的Si Ge四片式佩茨瓦尔(Petzval)物镜,实现了-60～160 ℃超宽温度范围的光学被动式消热差设计.改进系统并保持原系统光学性能参数,在空间频率20 lp/mm处,光学传递函数(MTF)保持在0.78以上,接近衍射极限,成像质量高而稳定.该系统可用于像元尺寸大于25 μm的非制冷凝视式焦平面阵列探测器.

For the requirement of extensive temperature adaptability of infrared optical systems, a refractive-diffractive hybrid approach is applied to an optical system with 114.7 mm focal length, F/1.5 F-number, ±2.5° field-of-view in the 3.2-4.2 μm waveband. The new designed hybrid system is passively athermalized over the temperature range from -60°C to 160°C with very high and stable imaging quality. The theoretical polychromatic modulation transfer function (MTF) is above 0.78 at space frequency of 20 lp/mm and is near to the diffraction-limitation. The lens is compatible with uncooled staring array imager with the picture element size over 25 μm.