光学相干断层成像在汽车电子三防漆无损检测上的应用

发布时间：2018-05-16 00:15

本文选题：光学相干断层成像 + 三防漆　；参考：《苏州大学》2016年硕士论文

【摘要】：光学相干断层成像技术(Optical Coherence Tomography,OCT)是基于低相干光干涉的光学成像技术,能够实现对材料的散射结构进行非接触和高分辨率的三维成像。目前OCT主要包括两种,谱域OCT和扫频OCT(Swept-source OCT)。其中,扫频OCT凭借更快的速度和更小的信号处理量而受到越来越多的关注和采用。扫频OCT在扫描成像速度、灵敏度以及分辨率上都能够满足电子制造行业对于无损检测的要求。三防漆(Conformal Coating)是汽车电子行业中经常使用到的一种透明和或半透明材料,它可以锁住印刷电路板和空气界面层的水分子,隔绝水汽的渗入,减小电路板表面发生离子迁移和腐蚀的可能性。但是,如果电路板上三防漆的涂层质量有问题,反而会加速电路板表面的离子迁移,从而导致印刷电路板上电路短路的后果。目前对于三防漆的质量管控仍然没有一个有效的办法,由三防漆质量而导致电子控制单元(Electronic Control Unit)不能满足设计、生产和使用的情况时有发生。本论文中将扫频OCT的系统性能和三防漆的物理特性相结合,搭建了一套扫频OCT测试系统平台,其纵向分辨率为13.48μm,其在三防漆中的成像深度达到了2.68mm,完全满足三防漆的分析需求。同时,设计了对于三防漆中常出现的气泡、分层、厚度不均匀以及固化不完全等现象的OCT分析方法,对于气泡和分层利用边缘检测和边界跟踪获取其界面的不规则形状;对于厚度不均匀利用OCT可纵向成像的特性对其进行纵向深度测量;对于固化不完全利用OCT在深度方向上的信号衰减系数表达三防漆由表及里的固化状态,并成功的进行了一些列实验和对比分析,证明了扫频OCT具有对三防漆涂覆质量进行无损检测的潜力。
[Abstract]:Optical coherence Tomography tomography (OCTT) is an optical imaging technique based on low coherent light interference, which can realize the non-contact and high-resolution three-dimensional imaging of the scattering structure of materials. At present, OCT mainly includes two kinds, spectral OCT and sweep OCT(Swept-source OCTT. Among them, frequency-sweeping OCT is paid more and more attention because of its faster speed and smaller signal processing capacity. Sweep OCT can meet the requirements of nondestructive testing in electronic manufacturing industry in terms of scan imaging speed, sensitivity and resolution. Formal Coatingis a transparent and semitransparent material often used in the automotive electronics industry. It can lock up water molecules in printed circuit boards and air interfacial layers and insulate the infiltration of water vapor. Reduce the possibility of ion migration and corrosion on the surface of circuit board. However, if the coating quality of the three coatings on the circuit board is defective, the ion migration on the surface of the circuit board will be accelerated, which will lead to the circuit short circuit on the printed circuit board. At present, there is still no effective way to control the quality of three-proof paint. The electronic Control unit can not satisfy the design, production and use. In this paper, the system performance of frequency-sweeping OCT is combined with the physical characteristics of three-anti-paint, and a OCT testing system is built. The longitudinal resolution of the system is 13.48 渭 m, and the imaging depth in the three-anti-paint is 2.68 mm, which fully meets the requirement of the analysis of three anti-paint. At the same time, the OCT analysis method is designed for bubble, stratification, uneven thickness and incomplete solidification, which often appear in the three anti-paint systems. For bubble and stratification, the irregular shape of the interface is obtained by edge detection and boundary tracking. For thickness inhomogeneity, the longitudinal depth of OCT can be measured by using the characteristics of longitudinal imaging, and the curing state is expressed by using the signal attenuation coefficient of OCT in the depth direction from the outside to the inside. Some series of experiments and comparative analysis have been successfully carried out, and it is proved that the sweep frequency OCT has the potential of nondestructive testing for the coating quality of three antipaint coatings.
【学位授予单位】：苏州大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U463.6;O436.1

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