50 mm～1 000 mm大变倍比变焦光学系统设计

为了满足机场跑道外来物光电探测系统对高像质、大变倍比、长焦距、小型化变焦镜头的需要，利用Zemax软件设计了一款50 mm～1 000 mm机械变焦镜头。该镜头采用机械补偿变焦结构，采用超低色散镜片来矫正变焦过程中引起的大色差问题，通过评价函数操作数对镜头的结构尺寸以及像质进行优化。通过优化设计，整个系统由28片球面透镜组成，系统总长小于400 mm，MTF在100 lp/mm条件下逼近衍射极限（MTF>0.2），RMS弥散斑半径在中心视场条件下小于5 μm，场曲小于0.1 mm，畸变小于1%，绘制了变倍组与补偿组的运动变化曲线，曲线平滑没有断点。分析结果表明:该系统满足机场跑道外来物探测的实际应用需求，对于大变倍比变焦光学系统设计具有一定的参考意义。

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.