不同偏振光对FPC打孔加工技术研究

发布时间：2018-11-08 16:54

【摘要】：随着现代高科技的发展,柔性电路板(Flexible Printed Circuit Board,简称FPC)对高密度、微孔径提出越来越高的要求,传统的机械加工方法已不能满足此需求。飞秒激光微加工具有加工精度高、热效应小、损伤阈值低等优点,在打孔中广泛应用。偏振态是激光的基本参数之一,对微孔加工的特性有重要影响。本论文研究不同偏振态飞秒光束对FPC微孔加工特性,主要研究内容如下:首先,介绍了激光与材料的作用机理,以及激光作用金属材料加工孔四个阶段的作用过程。讨论了现阶段激光冲击打孔法和轮廓迂回法的两种打孔方式,并分析特点以及适用范围。另外用公式推导了选用面积法测量损伤阈值的理论和可行性,设计光路和搭建实验系统测出了FPC在飞秒激光器单脉冲下的损伤阈值为25.44J/cm~2。其次,介绍了几种常见偏振光束的物理几何描述和四种偏振态的矢量光场。描述了空间光调制器的相位调制原理与4f光学系统原理。并设计了光路原理图,利用通过空间光调制器计算得到计算机全息图,结合1/2波片和1/4波片的快轴与水平方向的角度控制出线偏振光、圆偏振光、径向偏振光和角向偏振光。最后,设计并搭建了加工实验系统,其主要由飞秒激光器、空间光调制器、CCD相机和三维移动平台等组成。利用控制出的4种偏振态光束对FPC微孔加工特性分析,分析了脉冲能量对孔径影响,不同偏振态光束对微孔圆度及烧蚀程度等影响。从实验结果看出轴对称矢量的径向偏振光和角向偏振光加工后的孔径稍大于线偏振和圆偏振。并得出线偏振光烧蚀最为严重,圆度最差;圆偏振光烧蚀情况较好,圆度比线偏光好;径向偏振光和角向偏振光综合上烧蚀情况和圆度比前两种好,而且径向偏振光加工微孔质量更好。之后针对项目课题部分指标进行加工实验。
[Abstract]:With the development of modern high technology, flexible circuit board (Flexible Printed Circuit Board,) has put forward higher and higher requirements for high density and microaperture. The traditional machining method can not meet this demand. Femtosecond laser micromachining has many advantages such as high machining precision, low thermal effect and low damage threshold, so it is widely used in drilling. Polarization state is one of the basic parameters of laser, which has an important effect on the characteristics of micropore machining. The main contents of this thesis are as follows: firstly, the mechanism of laser interaction with materials and the four stages of laser processing of metal materials are introduced. In this paper, two kinds of drilling methods of laser impact drilling and contour roundabout are discussed, and their characteristics and application range are analyzed. In addition, the theory and feasibility of using the area method to measure the damage threshold are deduced. The damage threshold of FPC under the femtosecond laser pulse is 25.44 J / cm ~ (2) by designing an optical path and setting up an experimental system. Secondly, the physical geometry description of several common polarized light beams and the vector light fields of four kinds of polarization states are introduced. The principle of phase modulation and 4 f optical system of spatial light modulator are described. The principle diagram of optical path is designed, and the computer hologram is obtained by using spatial light modulator. Combined with the angle of fast axis and horizontal direction of 1 / 2 wave plate and 1 / 4 wave plate, the line polarized light and circularly polarized light are controlled. Radial polarized light and angular polarized light. Finally, a machining experiment system is designed and built, which consists of femtosecond laser, spatial light modulator, CCD camera and 3D mobile platform. The effects of pulse energy on pore diameter and the circularity and ablation degree of micropore in different polarization state beams were analyzed by analyzing the processing characteristics of FPC micropores by four kinds of controlled polarized beams. The experimental results show that the radial polarization and angular polarization of axisymmetric vector are slightly larger than that of linear and circular polarization. The results show that the ablation of linear polarized light is the most serious and the roundness is the worst, and the circular polarization is better than the linear polarization. The radial polarized light and the angular polarized light are better than the former two in the condition of ablation and roundness, and the quality of the micro-hole is better by the radial polarized light. After that, processing experiments are carried out for some indexes of the project.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN249;TN405

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