Design of cooled MWIR continuous zoom optical system for long-range surveillance

The continuous zoom optical system based on the cooled infrared detector can achieve high-quality imaging in multiple FOVs. Based on the continuous zoom theoretical model, this paper designs a MWIR continuous zoom athermal optical system consisting of only six lenses. The system has an F# of 4.0, a working range of 3.4 - 4.9 μm, a field of view ranging from 21.8°×17.5° to 1.6°×1.3°. All six lenses in the optical system contain aspherical surfaces with two diffraction surfaces to eliminate aberrations, optimizing the size and weight. The optical system compensates for temperature through an active focusing mechanism. The MWIR continuous zoom optical system has a compact structure and good imaging quality in the whole FOV in the temperature range of - 10 ℃ ~ + 60 ℃.