基于电磁扫描的电路板防护涂层覆盖性检测  

Detection technology of conformal coating coverage on circuit board based on electromagnetic scanning

作　　者：马云鹏 郑伟[1] 吴沁珂 刘建金 王超[1] Ma Yunpeng;Zheng Wei;Wu Qinke;Liu Jianjin;Wang Chao(Department of Optoelectronic Engineering,Key Laboratory of Optoelectronic Technology&Systems of Ministry of Education,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学光电工程学院光电技术及系统教育部重点实验室,重庆400044

出　　处：《电子测量与仪器学报》2025年第1期24-35,共12页Journal of Electronic Measurement and Instrumentation

基　　金：国家自然科学基金(61573073)项目资助。

摘　　要：防护涂层是保障印制电路板在复杂环境中可靠运行的关键措施,能有效防止外界因素的侵蚀和元器件老化。然而,目前的防护涂层检测技术仍不完善,难以实现涂层覆盖性的全面检测,从而影响了涂层的保护能力和长期稳定性。论文提出了一种基于电磁扫描和波动序列差异性度量的电路板防护涂层覆盖性检测方法。首先,分析了防护涂层的电磁屏蔽机理,为系统检测提供理论基础;其次,提出了改进的自适应波动序列差异性度量方法,该方法通过近场扫描获取电路板在涂层正常与薄弱状态下的电磁辐射数据,并应用小波分解进行数据降噪,进而运用改进的差异性度量算法计算两类波动序列距离值,以识别涂层缺陷区域。最后,通过仿真和实测实验验证该方法的有效性。实验结果表明该方法能有效提升涂层检测的准确性与可靠性,克服了传统检测手段在涂层覆盖性评估中的不足,为电磁屏蔽技术的理论研究与工程应用提供了新视角。Conformal coatings are essential for ensuring the reliable operation of printed circuit boards(PCBs)in complex environments,effectively preventing external corrosion and component aging.However,current conformal coating detection techniques remain inadequate,making it difficult to achieve comprehensive coverage assessment,which affects the coating’s protective capability and longterm stability.This paper proposes a PCB conformal coating coverage detection method based on electromagnetic scanning and fluctuation sequence difference measurement.First,the electromagnetic shielding mechanism of the conformal coating is analyzed,providing a theoretical foundation for system detection.Next,an improved adaptive fluctuation sequence difference measurement method is proposed.This method acquires electromagnetic radiation data of the PCB under normal and weakened coating conditions through nearfield scanning,applies wavelet decomposition for noise reduction,and uses an improved difference measurement algorithm to calculate the distance between two fluctuation sequences to identify coating defect areas.Finally,the effectiveness of this method is verified through simulations and experimental measurements.The results demonstrate that this method significantly enhances the accuracy and reliability of coating detection,overcoming limitations in traditional coating assessment methods and offering new perspectives for the theoretical research and engineering applications of electromagnetic shielding technology.

关 键 词：防护涂层 近场扫描 波动序列 差异性度量 覆盖性检测 

分 类 号：TP274.5[自动化与计算机技术—检测技术与自动化装置] TN98[自动化与计算机技术—控制科学与工程]