由于自动化机器视觉系统和装配线之间所需的空间差异很大，传统的定焦镜头难以满足，需要一款具有大跨度工作距的光学成像系统。基于物面位置改变对系统初级像差影响的理论，运用Zemax软件多重结构的功能，在设定的多个物距下进行优化设计，从而达到对宽工作距的需求。光学系统设计结果表明：调焦范围从146 mm到无穷远；最大光圈F数为2.8，中心在空间频率100 lp/mm处调制传递函数(MTF)值大于0.3，0.7视场在72 lp／mm处调制传递函数大于0.3。这样的成像效果可以代替人工，观察到装配线上远近各个方位的零件运作情况，提高自动化的程度。

As a result of the big difference in the required space between automation machine vision system and assembly line, the traditional fixed-focus lens cannot meet the practical requirements. There is a need for the big span working distance of optical imaging system. Based on the influence of changes in the object surface position on the primary aberration, with multiple structure function of Zemax software, the wide working distance lens is designed. The results show that the focusing range is from 146 mm to infinity, and the maximum aperture is F2.8. At the center field-of-view (FOV), the modulation transfet function (MTF) is greater than 0.3 at the spatial frequency of 100 lp/mm and the MTF at the 0.7 FOV is greater than 0.3 at the spatial frequency of 72 lp/mm. Such a system can replace the manual work to observe the whole assembly line and thus can improve the degree of automation.