Design Of Cooling Infrared Dual-Band 3x Zoom Optical System

With the rapid development of infrared technology in recent years,the infrared dualband continuous zoom system has become the research direction for the development and application of infrared technology in various countries in the world.Compared with the traditional zoom,the dual-band zoom system can search for a large field of view target and scan the target through a small field of view;on the other hand,it can simultaneously detect target information in the middle and long wave bands.Retaining the advantages of a single band and dual-band detection capabilities can effectively screen camouflage information,which makes the system's ability to acquire target information significantly improved.The dissertation starts with the research work of infrared dual-band system and infrared zoom system made by domestic and foreign experts and scholars in recent years,summarized the design indexes and design results of the cooling infrared dual-band zoom optical system in this subject.Through continuous calculation,optimization and analysis,a refrigerated infrared dual-band zoom optical system was finally designed.The zoom ratio of this system is 3 times.Based on the mechanical positive group compensation,the image plane is stabilized in a dual-band continuous zoom.The relative motion of the zoom group and the compensation group without inflection points is obtained by drawing and analyzing the cam curve.curve.Based on the more difficult transmission structure,the system designed two bands of 3.7?m to 4.8?m for medium wave and 7.7?m to 10.3?m for long wave to image in the same structure,and realized confocal.A secondary imaging structure was added after the zoom structure to achieve 100% cold diaphragm efficiency of the refrigerated infrared system.By characterizing the image quality evaluation methods such as the transfer function,dot plot,and aberration curve of the refrigerated infrared dual-band zoom optical system,the MTF of the entire optical system at 17lp/mm is in all cases,they are close to the diffraction limit.When the system is in the mid-wave band,the MTFs in the three fields of view are not less than 0.5,and when the system is in the long-wave band,the MTFs are not less than 0.3.It can be seen from the dot map that the root mean square radius of the diffuse spot is basically smaller than a pixel size of 30?m.Finally,the cold reflections generated by the system were analyzed by methods such as reverse ray tracing;and the no heating design in the range of-40?C?+60?C was achieved by an electromechanical active method.The system structure is reasonable,the imaging quality is good,and it has certain practicability.