阐述了现代变焦距目镜的特点及其设计方法, 给出了一种三倍变焦目镜设计的结构形式。这种变焦目镜结构紧凑, 成像质量优异, 可以取代传统的二倍变焦目镜, 是一种有应用价值的变焦目镜形式。该设计将目镜的出瞳作为变量, 使入瞳位置保持稳定以衔接物镜出瞳, 并最终得到了一个8.24~24.1mm的变焦目镜。采用一种新型的方法绘制了凸轮曲线图形, 该公式简单、准确, 可以替代老的计算公式, 值得推广应用。

The characteristic and design procedures of modern zoom eyepiece are expounded. A zoom eyepiece of layout for treble is given. The characteristic of this zoom eyepiece is that the system is very compact and image quality is excellent,which can displace old double zoom eyepiece,so it is valuable for adhibition.This design will take the exit pupil location as variable to keep entrance pupil location steady for connecting objective exit pupil, and a zoom eyepiece of 8.24~24.1mm is got. A new method that is simple and accurate drawing cam curve figure is used, so it is worthy of popularizing and adhibition.