基于激光光散射层貌术的蓝宝石内部缺陷检测系统
文献类型：学位论文
| 作者 | 刘洋 |
| 学位类别 | 硕士 |
| 答辩日期 | 2014 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 徐文东 |
| 关键词 | 激光技术 机器视觉 缺陷检测 散射 图像分析 |
| 其他题名 | A Detecting System of Sapphire Internal Defects Based on Laser Light Scattering Tomography |
| 中文摘要 | 作为制作LED衬底的基本材料，蓝宝石材料的内部缺陷会给氮化镓（GaN）有机化学气相沉积（MOCVD）过程带来不利影响，因此限制了蓝宝石对于高质量LED制造的适用性，直接影响了高亮度LED衬底的晶片制造成品率。 通过大量的调研发现，使用激光光散射层貌术来检验和筛选蓝宝石材料不具破坏性，经济有效，是一种可重复且高度可预测的方法。本文首先对国内外蓝宝石衬底和机器视觉技术的应用现状和发展前景进行了简单介绍，从系统需求出发，指出了用激光光散射层貌术来改进高亮度光照法进行缺陷检测的优势，并简要阐述了激光光散射层貌术实现缺陷定位的原理。随着计算机技术的发展和普及，机器视觉技术越来越广泛的应用在工业在线检测上。与人工检测手段相比，机器视觉技术具有速度快、稳定性好、自动化程度高、能连续工作等人眼检测不可比拟的优点，因此广泛的应用于工业生产的各个领域。本文基于机器视觉技术，完成了蓝宝石内部缺陷检测系统硬件方面的构建，并对蓝宝石内部缺陷检测系统的器件组成、参数设定和控制架构进行了详细介绍。在深入研究了图像处理和图像分析技术，包括图像预处理、图像分割和特征提取等技术手段之后，确定了合理的图像处理和分析算法。接下来本文设计了蓝宝石内部缺陷检测系统的软件流程，完成了运动控制模块、图像采集模块及图像分析模块的代码编制，从而完成了整个软件系统的设计。最后，通过对样品的检测实现了对蓝宝石内部检测系统的性能测试。实验结果表明，该系统能有效的识别出蓝宝石晶体中的散射颗粒缺陷，并对其在棒状蓝宝石晶体深度方向上准确定位，实现了亚毫米的定位精度，达到了预定设计要求。 总的来说，本文针对蓝宝石衬底加工要求，在机器视觉技术的基础上，利用LabVIEW及NI公司的图像采集卡和数据采集卡研制了一套基于激光光散射层貌术的蓝宝石内部缺陷检测定位系统，利用高强度的线状激光照射下缺陷产生的光散射效应对蓝宝石晶体进行逐层扫描和图像采集，运用图像增强、图像分割及图像提取等图像处理手段对采集到的图像进行缺陷提取和分析，实现了对蓝宝石内部缺陷的检测和定位，并提升了检测效率，大大降低了蓝宝石衬底的生产成本，具有广阔的应用前景。 |
| 英文摘要 | Sapphire is the basic material of LED substrate, thus the internal defects in it have adverse impacts on the GaN organic chemical vapor deposition (MOCVD) process, which limits the applicability of sapphire material for high quality LED manufacturing and directly affects the production yield of high-brightness LED substrate chips. Plenty of literatures prove that the laser light scattering tomography is a nondestructive, economic and effective, repeatable and highly predictable way to test and filter the sapphire material. This paper first gives an outline of the application status and development prospect of the sapphire substrate and machine vision technology at home and abroad, points out the advantages of using laser light scattering tomography to improve the high brightness illumination method for defect detection based on the system requirements, and briefly expounds the principle of laser light scattering tomography in defect locating. With the development and popularization of computer technology, the machine vision technology is more and more widely applied in industrial on-line detection. Compared with manual inspection means, the machine vision technology has the incomparable advantage of rapidly, high stability, high degree of automation, and capacity of continuous, therefore has been widely used in various fields of industrial production. Based on machine vision technology, this paper builds up the hardware platform of sapphire internal defects detection system, and gives the details of components, parameter setting and control architecture. After an intensive study of image processing and image analysis technology, including image preprocessing, image segmentation and feature extraction technology, the reasonable algorithm of image processing and analysis is determined. Then the software process of sapphire internal defects detection system is designed, and the codes for movement control module, image acquisition module and image analysis module are programed too. After that the design of the whole software system is completed. At last, the performance of this system is tested by inspecting samples. The experimental results show that the system can effectively identify the scattering particles defects and position them in depth direction of bar sapphire crystal with sub-millimeter accuracy, which meet the design requirement. In summary, in view of the processing requirements of sapphire substrate and based on machine vision technique, this paper builds up an internal defects detection and positioning system for sapphire in basis of laser light scattering tomography. LabVIEW and image acquisition card and data acquisition card from NI Company are adopted in this system. The detection and positioning of internal defects in sapphire crystal are realized by scanning the sapphire crystal layer by layer through the light scattering effect generated by the irradiation of high-intensity linear laser on defects. A lot of image processing methods such as image enhancement, image segmentation and image extraction are adopted to extract and analyze the defects, enhancing the real-time performance and visuality of this system. This system can improve the detection efficiency, and reduce the production cost of sapphire substrate greatly, which makes it a system with broad application prospect. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16849]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 刘洋. 基于激光光散射层貌术的蓝宝石内部缺陷检测系统[D]. 中国科学院上海光学精密机械研究所. 2014. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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