长波制冷型热像仪光学系统设计

Optical System Design of a Refrigeration Type Long Wave Thermal Imager

根据制冷型热像仪的技术要求,从机电补偿式消热差出发,设计了一套三片式、结构紧凑、质量较轻的制冷红外热像仪光学系统。热像仪工作波段为8μm～12μm,光学系统焦距50mm,F数为1.7,视场11.2°×8.2°。光学系统的成像质量接近衍射极限,在探测器的Nyquist频率处各视场的MTF值均大于0.5,各视场的弥散斑直径小于0.05mm,满足热像仪的成像要求。

According to the technical requtrements ot me reutgc^tuuL~ ,yl~ ~,v., _. ~, cal compensation methods to eliminate the thermal difference, a optical system of a refrigeration type LWlR thermal im- ager which has 3 elements, tight structure and light weight was designed.Its wavelength range is from 8gm to 121sin. The optical parameters of the thermal imager are as following： focal length f＇ is 50 mm, F-number is F/1.7, full field-of^view 2 ~is 11.2~~8.2~.The imaging quality of optical system is close to the diffraction limit, the MTF values of each FOV are higher than 0.5 at the Nyquist frequency of the detector, the dispersion spot diameters of each field of view are less than 0.05ram, meeting the imaging requirements of thermal imager.