中波红外景象投影光学系统消热差设计

Abstract

For the requirements of the infrared imaging system performance testing and evaluation applications,an athermalized mid-wave infrared scene projector was designed,based on Digital Micro-mirror Device(DMD).The aberration and design method of the optical system for infrared scene projector were analyzed,and the athermalization for the scene projector was also discussed.A splitting lens and a compensation lens were used to address the light splitting and aberration balancing problems in the illumination of the telecentric projection systems with a large relative aperture.So the resolution and uniformity were improved,and the field of view was increased.The optical system is composed of a telecentric projection lens and a Kohler illumination lens with tilted image plane.The optical passive athermalization method was introduced into the design,which improved the stability of the system.The spectral band of the system is 3～5 μm,the focal length is 255 mm with a F/2.6 relative aperture,the field of view is 5.1°,and the exit pupil distance is 200 mm.The image quality of the system approaches diffraction limit with MTF0.6 at spatial frequency 17 lp/mm in the whole operating temperature range of-20 ℃~ 60 ℃.The proposed athermalized mial-wave infrared scene projector has the advantages of high resolution,excellent uniformity,compact size and low weight.