基于液体透镜的自动变焦扫描镜头的设计与验证

Application of autofocus technology based on zoom lens of scanning lens

由于定焦镜头自身的景深问题使传统的扫码器不具备大的工作距离。为了满足工作人员在不更换扫描器的情况下既能实现近距离的信息读取又能实现十几米外的信息读取,研发了一款基于电润湿(electrowetting on dielectric,EWOD)液体透镜的自动变焦扫描镜头。通过调整液体镜片形状来实现镜头参数特别是焦距的变化,使得从近到远的所有对象都能成像在焦面上,从而达到自动变焦的效果。通过Zemax软件设计出一款成像范围为80 mm至无穷远的自动变焦扫描镜头,并完成了成像质量的验证。

Limited by depth of field of the prime lens,the traditional code scanner cannot work properly in large distance.In order to satisfy the condition that staffs need to scan the code for both close range and far range(over 10 meters)without switch the code scanner,the design based on electrowetting on dielectric(EWOD)liquid autofocus lenses was developed.Parameters of the lenses especially the effective focal length changed by adjusting the shape of the liquid lenses;so that all the objects,from far to close,formed the image on the image plane,and so autofocus function was achieved.With Zemax,an autofocus scanner lenses set with effective working range from 80 mm to infinity were designed and tested.