Zoom lens with stationary external entrance pupil and internal stop is a type of special optical system that can be used in cascaded optics to meet the requirements of long focal length or variable magnification. We proposed a 4× zoom lens to improve the pupil walking limitation observed in the conventional design. Varifocal- and pupil-stable differential equations are presented and a paraxial design of the lens with two moving parts was developed. Moreover, the zoom lens, which functions in the visible waveband 500 nm~750 nm, is designed using seven types of common optical glasses, has a constant f-number of 10 and focal range of 100 mm~400 mm, and achieves pupil walking in the range −3.9 mm to +4.3 mm. The results demonstrate that the design had good image quality and tolerance characteristics. Owing to the limited pupil walking and zoom capability, the scheme is of considerable interest for application in electrical optical systems.

中文翻译：

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具有稳定外入射光瞳和内光阑的 4 倍变焦镜头的光学设计

固定外入瞳内光阑变焦镜头是一种特殊的光学系统，可用于级联光学系统，以满足长焦距或变倍率的要求。我们提出了一个 4 倍变焦镜头来改善在传统设计中观察到的瞳孔行走限制。提出了变焦和瞳孔稳定的微分方程，并开发了具有两个移动部件的透镜的近轴设计。此外，在可见波段 500 nm~750 nm 工作的变焦镜头采用 7 种常见光学眼镜设计，具有恒定的f-数量为10，焦距为100 mm~400 mm，实现瞳孔在-3.9 mm至+4.3 mm范围内行走。结果表明，该设计具有良好的图像质量和容差特性。由于瞳孔行走和变焦能力有限，该方案在电子光学系统中的应用具有相当大的意义。