ZEMAX和CODE V等光学设计软件, 虽然有很强的优化功能, 但如果想得到好的设计结果, 初始解的选择至关重要。求初始解的普遍做法是, 将已有的光学系统或其中某一个组元拿来进行缩放。这种办法带有盲目性。另一种方法就是利用高斯光学和三级像差理论求变焦距物镜的初始解。这一方法有助于创新设计, 但却很少被应用。本文介绍了作者在运用这一方法过程中产生的观点、理念、经验和成果。本文通过一个十倍变焦距物镜设计实例, 详细介绍了求初始解的过程, 为了验证该初始解的效果, 还用ZEMAX进行了像差优化。为了增加说服力, 设计过程的每一步, 都给出了具体的数据, 包括经ZEMAX优化得到的最后结果。

Despite the optical design softwares like ZEMAX and CODE V own the strong optimization features, the selection of preliminary solution is still critical if a good design result is expected. A common practice for finding a preliminary solution is to scale an existing optical system or one of its components. However, this approach has a certain blindness. Another method is using the Gaussian optics and the third-order aberration theory to find the initial solution of the zoom objective lens. This approach is helpful to produce innovative ideas in design but is rarely used. The ideas, concept, experiences, and results generated by this approach are introduced in this paper. Through the design example of a ten-fold zoom objective lens, the process of finding the preliminary solution is introduced in detail. In order to verify the initial solution obtained, the aberration optimization is also performed using ZEMAX. For the sake of increasing power of conviction, specific data is given at each step of the design process, including the final results obtained by ZEMAX optimization.