Design of 50 mm~1 000 mm zoom optical system with high zoom ratio

In order to meet the requirements of the high image quality, high zoom ratio, long focus and miniaturization zoom optical system for the foreign object debris detection, a 50 mm~1 000 mm zoom optical system based on Zemax optical software was designed. The mechanical compensation zoom type was adopted to realize the zoom system, the extra-low dispersion lenses were adopted to reduce the chromatic aberration and secondary spectrum was introduced by the long focal length. Meanwhile, the merit function operands was used to simultaneously optimize the image quality and design the miniaturization system. The system contains 28 lenses and the total length is less than 400 mm by optimizing design. The on-axis modulation transfer function (MTF) is above 0.2 at 100 lp/mm, which means near the diffraction limit generally. The system field curvature is less than 0.1 mm and the distortion is less than 1%. The system can satisfy the change regulation of the mechanical compensation cam curve, and the curve is continuous and smooth. The analysis results show that the system can meet the practical application requirements of the foreign object debris detection around airport runway, furthermore, it’s significant for the design of large zoom ratio zoom optical system.