超高倍变焦光学系统设计

设计了一套焦距f′=8 mm~2 400 mm的超高倍变焦光学系统，对可见光波段成像。采用多组元全动型变焦结构，在实现高变倍比的前提下不增加系统尺寸；在普通衍射透镜的基础上，分析了谐衍射元件的成像特性及色散，减小长焦距所引入的色差和二级光谱；给出了新型非球面方程及特性，解决了普通非球面方程项数选取复杂的问题。在上述理论基础上，利用Zemax光学设计软件对系统进行仿真，引入4个谐衍射面和4个新型非球面。设计结果表明，在奈奎斯特频率50lp/mm时，调制传递函数曲线均在0.5以上，成像质量较好，可广泛应用于军事、航天等领域。

Design of ultra-high zoom optical system

An ultra-high zoom optical system with the focal length of 8 mm~2 400 mm was designed for visible light band imaging. Using multi-component fully dynamic zoom structure, it does not increase the size of system on the premise of high variable ratio.Based on the ordinary diffractive lenses, the imaging characteristics and dispersion of harmonic diffractive element were analyzed, as well as the chromatic aberration and secondary spectrum introduced by reducing the long focal length. The new aspherical equations and characteristics were given, which could solve the problem of complex selection of the number of ordinary aspherical equations.On the basis of the above theory, the system was simulated by Zemax optical design software, and 4 harmonic diffraction surfaces and 4 new aspheric surfaces were introduced. The design results show that, at the Nyquist frequency of 50 lp/mm, the modulation transfer function curves are all above 0.5. The imaging quality is good, and it can be widely used in military and aerospace fields.