Design of linearization double-linkage IR zoom lens

A linearization double-group linkage zoom lens was presented based on the 640x512 cooled FPA. This configuration's zoom groups and compensate groups are moved linear zing, omit zoom cam which control the movement of zoom curve make common double-linkage zoom lens easily. This configuration is similarity to optical compensate zoom has a little image displacement, but it is not influence the image quality when the image displacement control in allow range. This lens was placed at cold shield and 100% cold shield efficiency had reached. Moreover, detailed design and image quality were given by CODE optical software. After analysis, MTF approaches diffraction limit. The results show that this optical system has large zoom ratio, and excellent image quality.