制冷式红外双波段共光路折衍混合摄远物镜设计

Design of Cooled Infrared Dual-Band Common Path Refractive-Diffractive Telephoto Objective

针对远程红外目标探测的需求,为提高光学系统在复杂环境下的探测能力,设计了制冷式红外双波段共光路折衍混合摄远物镜。摄远物镜的工作波段为红外中波(3～5μm)及红外长波(8～12μm),采用透射式共光路结构,由物镜和中继镜组成。摄远物镜焦距为-200mm,F数为2.8,全视场角为3.2°。探测器选用2/3inch(1inch=25.4mm)的HgCdTe红外中波焦平面阵列,分辨率为320pixel×256pixel,像元尺寸为30μm。该摄远物镜像质优良,在截止频率为17lp/mm时,红外中波各视场的调制传递函数(MTF)值超过0.5,红外长波的MTF值超过0.3;各视场点列图均方根半径均远小于艾里斑半径;实现了100%冷光阑效率。该红外摄远物镜可用于坦克红外观瞄等系统。

Aiming at the needs of remote infrared target detection, for improving the detection ability of optical system in a complex environment, the cooled common path infrared dual-band refractive-diffractive telephoto objective is designed. The working wave-band of the telephoto objective covers the infrared medium-wave （3-5 μm） and infrared long-wave （8-12 fire）. A transmission common path structure is used in this telephoto objective. The telephoto objective consists of objective and relay lens. The focal length of the telephoto objective is --200 mm, the F number is 2.8, and the full field of view is 3.2＂. The detector adopted is HgCdTe mid-wave infrared focal plane array of 2/3 inch （1 inch--25.4 ram）. Its resolution is 320 pixelX 256 pixel and pixel size is 30 μm. The image quality of this telephoto objective is prefect. At cut-off frequency of 17 lp/mm, the modulation transfer function （MTF） of the infrared medium-wave is greater than 0.5 for each field of view, and the MTF of the infrared long- wave is greater than 0.3 for each field of view. The root mean square radius of spot diagram for the each field of view is much smaller than Airy disk radius. The cold shield efficiency is 100%. This infrared telephoto objective can be used in the observation-aiming system of the tank.