Archimedes螺线式Fresnel透镜的设计及加工方法

Design and machining of an Archimedes spiral Fresnel lens

为解决传统同心环式Fresnel透镜及其模具金刚石刀具加工存在对加工系统要求过高及效率较低的问题,给出了Archimedes螺线式Fresnel透镜的设计方法。从几何聚光比和能流透射率方面对比了2种透镜的性能,发现两者性能基本一致。分析了大型Fresnel透镜及其模具金刚石车削机床的运动。计算了Archimedes螺线式Fresnel透镜车削加工的刀具轨迹。对比机床各轴精度对透镜光学性能的影响,发现刀具摆角、透镜法线方向进给轴的精度影响最大,采用附加沿刀具轴线方向微进给装置的机床结构能有效提高加工精度。

The production of homocentric loop Fresnel lens using diamond cutters with turning needs extremely high performance processing systems, but the production efficiencies are＂ low. This paper gives a design method for Archimedes spiral Fresnel lens that are easy to produce. Comparison of the geometrical focusing and the energy transmissivities shows that those two kinds of Fresnel lens are almost the same, A method is then given to design the turning cutter track for large Archimedes spiral Fresnel lenses. The analysis considers the influence of the NC turning machine axes precision on the lenses optical capabilities. The primary factors affecting the lenses are the angle of cutter swing and the feed normal to the lens surface. The precision can be enhanced by a micro feeding device for the axial cutter feed.