印刷电路板LED贴片质量在线视觉检测系统

发布时间：2018-02-21 03:48

本文关键词： 模板匹配图像增强缺陷检测平均灰度值　出处：《沈阳工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：柔性印刷电路板(Flexible Printed Circuit,FPC)是一种具有高度可靠性和可挠性的印刷电路板,其应用越来越广泛。本文研究的柔性印刷电路板主要应用于笔记本电脑键盘,且键盘上贴片式LED灯的粘贴需经过点银、贴片、封胶这三个工艺,对于这三个工艺中出现的缺陷,现在大多数企业所使用的检测方法还停留在人工目测方式上。与传统的刚性印刷电路板相比,本文研究的柔性电路板由于连接盘的透明特性,以及与刚性电路板的材质有很大不同,其成像效果也不同,且两者的生产工艺也完全不同,所以不能将传统的刚性电路板的检测方法直接用于柔性印刷电路板。因此,需要专门研究一套柔性印刷电路板点银、贴片、封胶缺陷在线检测系统,以提高检测速度,降低企业的用人成本。本文研究的内容主要集中在如下几个方面:(1)根据现有FPC贴片生产线设计了FPC点银、贴片、封胶缺陷检测的硬件方案,并根据线路分布特征和需求选取了合适的硬件成像系统。(2)利用图像增强与形态学对银点所在的区域进行粗定位,在粗定位的基础上对银点实现精定位;通过银点区域与滞留孔区域的差集与位置关系进行银点偏位缺陷检测;通过提取出的背景轮廓的长宽进行银点拉丝超标缺陷检测。(3)对贴片过程中出现的漏粘、异物、粘斜、偏移缺陷进行检测:首先利用基于形状的模板匹配定位连接盘,通过最小外接矩形获取贴片的有效范围区域。利用模板匹配检测漏粘缺陷;通过平均灰度值比较法检测LED上的异物缺陷;采用有效区域与LED区域的交集与差集对粘斜与偏移缺陷进行检测。(4)提出了封胶缺陷检测方法,通过模板匹配对LED灯进行定位;利用黑胶区域与黑胶的有效区域的比例关系进行多胶与少胶缺陷检测;通过平均灰度值比较法,检测灯孔覆盖缺陷。所提出的检测方法已经应用在了工业生产线上,其检测时间满足工业现场的要求,且具有较高的检测准确率。
[Abstract]:Flexible Printed Circuit Board (FPC) is a kind of printed circuit board with high reliability and flexibility, which is used more and more widely. And the paste of the LED lamp on the keyboard needs to go through the three processes of silver, patch and glue, for the defects in these three processes, At present, the detection methods used in most enterprises are still in manual visual mode. Compared with the traditional rigid printed circuit board, the flexible circuit board studied in this paper is due to the transparent characteristics of the connecting disk. And the material is very different from the rigid circuit board, its imaging effect is also different, and the production technology of the two is completely different, so the traditional testing method of the rigid circuit board can not be directly used in the flexible printed circuit board. Need to study a flexible printed circuit board silver spot, patch, sealing defects online detection system, in order to improve the detection speed, This paper mainly focuses on the following aspects: 1) according to the existing FPC patch production line, we designed the hardware scheme of FPC spot silver, patch, sealing defect detection, According to the distribution characteristics and requirements of the line, the appropriate hardware imaging system is selected. The image enhancement and morphology are used to locate the region of silver points, and the fine location of silver points is realized on the basis of coarse location. The defect of silver spot deviation is detected by the relation between the difference set and position of the silver spot region and the detention hole area, and the defect detection of the silver dot drawing wire exceeding the standard is carried out by the length and width of the extracted background contour. The offset defect is detected: firstly, the shape based template matching is used to locate the connection disk, and the effective range of the patch is obtained by the minimum external rectangle. The missing viscosity defect is detected by template matching. The foreign body defects on LED are detected by the comparison method of average gray value, and the glue sealing defect detection method is put forward by using the intersection and difference set of effective region and LED region. The sealing defect detection method is put forward, and the LED lamp is located by template matching. Using the ratio relationship between the rye region and the effective region of rye, the defect detection of polygel and less glue is carried out. The light hole covering defect is detected by the comparison of average gray value. The proposed method has been applied to the industrial production line. The detection time meets the requirements of the industrial site and has a high detection accuracy.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.41;TN41

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