A02-菲涅耳透镜(Fresnel lens)模仁单点钻石车削研究

郑颖聪1、蔡元勋1、简瑞廷1、陈伟仁1、林惠萍1、陈明源2

摘要

菲涅耳透镜由于具有将传统透镜薄型化之作用，因此已广泛被运用于3C、太阳能、LED照明、车灯、路灯等产业。但因菲涅耳透镜具有微结构，在加工过程中，常无法达到模仁尺寸精度要求。

本研究主要是以超精密单点钻石车削方式来探讨加工参数(切削深度、进给速率、主轴转速)对菲涅耳透镜(Fresnel lens)模仁之表面粗糙度与微结构深度之影响。

由研究实验结果可知，当主轴转速2000rpm、进给速率0.5mm/min、切削深度0.4μm时，可获得最佳模仁表面粗糙度。而影响模仁表面粗糙度最关键的因子进给速率，其次是主轴转速。因此若欲提升模仁表面粗糙度，降低进给速率将可获得最佳效果，但加工时间将会拉长，故适当的提升主轴转速将可降低加工时间，并提升表面粗糙度。

关键词：菲涅耳透镜、超精密加工、单晶钻石刀具、模仁、表面粗糙度。

Abstract
Since Fresnel lens is equipped with thinning feature of traditional lens, Fresnel lens is widely applied in 3C, solar energy, LED lamination, car lamp and roadway lighting. Due to micro-Fresnel lens structure, machining process cannot achieve the required dimensional accuracy of mold insert.
This research uses ultra-precision single-point diamond turning approach to study the influence of machining parameters (cutting depth, feed rate, spindle turning speed) on surface roughness and micro-structure depth of Fresnel lens.
Research results indicate when spindle turning speed reaches 2000rpm, feed rate is 0.5mm/min and cutting depth is 0.4μm, the best mold insert surface roughness can be obtained. The key factor to affect mold insert surface roughness is the feed rate. The second important factor is spindle turning speed. To increase mold insert surface roughness, reduction of the feed rate can obtain the best effect, however machining time will prolong. Therefore proper increase of spindle turning speed can reduce machining time and increase surface roughness.

Keyword: Fresnel lens, Ultra precision machining, single-point diamond tools, mold insert, surface roughness.