小倍率大视场的双远心物镜具有低畸变、大景深的优点,在机器视觉工业在线检测领域应用广泛。根据双远心镜头对结构参数的要求,运用光学设计软件Zemax设计了一款高分辨率、大视场、结构简单的双远心物镜。该物镜采用近似对称结构,合理的控制畸变和色差,经过像差优化,实现了长工作距(大于200 mm)、低倍率(β=－0.1)、低畸变(小于0.015%)、高分辨(1/2＂CCD全视场MTF在200 lp/mm处大于0.05)、大景深(±32 mm)和双远心系统的设计要求。重点阐述了物镜的设计过程及镜头的敏感度分析,分析影响镜头像质的主要加工和装配因素,为有效抑制由于生产制造过程中的偏差对镜头像质的影响提供参考。

The double telecentric lenses with low magnification and large field-of-view present the advantages of low distortion and large depth of field,so they are widely applied in the machine vision industrial online detection.In this paper,a telecentric lens with high definition,large field-of-view and simple configuration is designed with the optics design software Zemax based on the demand of parameters for telecentric lens.The lens uses a nearly symmetrical structure to control the distortion and lateral color.After the optimization of optical aberrations,it achieves a long working distance (greater than 200 mm),low ratio (β=-0.1),low distortion (< 0.015%),high resolution (for 1/2"CCD the MTF of full field at 200 lp/mm is greater than 0.05),large depth of field (±32 mm) and satisfies the double telecentric requirements.This paper focuses on the design process and sensitivity analysis of the objective lens,and gives the main factors that affect the lens image quality in the manufacturing process and assembly.To effectively inhibit the deviation in the process of production and manufacturing,the sensitivity analysis provides a theoretical basis to ensure the lens image quality.