分孔径中波红外多光谱成像光学系统的设计

Design of aperture-divided multispectral imaging system in mid-infrared band

为了同时获得目标的红外图像信息和光谱信息,设计了一种分孔径中波红外分波段成像光学系统。该系统可将位于成像器前方不同波段的目标红外场景通过分孔径方式成像到红外制冷型探测器的4个区域上。该系统通过内部分孔径的办法,在不同通道内放置滤光片的方式,实现在一个探测器上对3.5μm～4.1μm、4.4μm～5μm、3.5μm～5μm、4.4μm不同波段的目标同时成像。该系统F数为1.93,单通道的焦距为60mm,MTF接近衍射极限,同时实现了在-40℃～+60℃的无热化需求,可以满足应用和指标需求。

With the purpose for simultaneously capturing infrared pictures and spectral information of an object, a fourchannel aperturedivided and multispectral optical imaging system was designed and analyzed. Relying on the approach of separating the aperture and placing the appropriate filter in individual channel, the object with four infrared bands can be imaged on the corresponding regions of the cooled infrared detector. Four infrared bands include 3.5 μm^4.1 μm, 4.4 μm^5 μm, 3.5 μm^5 μm as well as 4.4 μm, respectively. The Fnumber of the system is 1.93, and the focal length of the single channel is 60mm.Moreover, the modulation transfer function （MTF） is close to the diffraction limit.In particularly, our system satisfies the demanding of athermalization in the range of -40 ~＋60℃. The simulation results show that the performances of the system can meet the requirement of design.