Research On Athermalization Of Zoom Lens System For The Infrared Seeker

The infrared zoom lens get more and more attention of the researcher for it not onlycan detect the object in long focal length, but also can scrutinize the object in short focallength, and not missing the information when continues change the focal length. But it isstill difficulty to make it work in the finite volume as well as the large temperature range.Therefore, study the athermalization of the infrared zoom lens appears extremelyimportant. Based on the platform of the infrared seeker, the dissertation successfullydesign the athermalization of the infrared zoom systems using the optical compensationmethod. The system could work in the temperature range of-45oC~55oCas well as inthe50mm~150mmzoom range. The quality of imaging system meets requirement. Thespecific work include the following contents:Firstly, according to the characteristics of infrared seeker optical system, theworking waves of the seeker is determined. Then the final parameters of the zoom opticalsystem is calculated.Secondly, several kinds of methods to compensate the zoom optical system isintroduced, and focus on analysising the gaussian solution of the mechanicalcompensation method which include the positive and negative means; Based on thenegative compensation way, the initial structure of the zoom optical system is putforward with the software of MATLAB programming the and the zoom optical system isdesigned with CODEV.Thirdly, the three methods which could athermalization the optical system areintroduced. The quality of the imaging system which caused by temperature changes isanalysed; Then athermalization of the infrared zoom lens is designed using the opticalpassive method as well as the software of CODEV. Bring the diffraction element andaspherical in the optical system design in order to solve the difficult problem ofathermalization infrared zoom system. The image quality of the system is analysed,including the MTF and the plot diagram, distortion curve, etc.Finally, the concept and forming conditions of the cold reflection is introduced, thecold reflection of the whole zoom optical system is analysed; the surface profile of thediffractive optical elements is simulated with CODEV macros. The processing method isputs forward according to current processing technology.