The Design Of Illumination System In Industrial Automatic Optical Inspection

Automatic Optical Inspection (AOI) technology has been successfully applied to detect defects on the Printed Circuit Board (PCB) since 1980's. This research is focusing on illumination design of solder joint inspection based on the illumination technology of AOI, and then presents a computer-aided illumination design method using the TracePro software, which avoids the flaws in the traditional optical design, simplifies the process and reduces cost and improves efficiency.This dissertation consists of three parts:First, we introduce AOI technology applied to the PCB inspection and its development, especially on the PCB solder joint inspection technology.Next, we summarize the basic knowledge of the illumination design, and then use them flexibly to the illumination design of solder joint inspection. Considering the formation of the solder joint, the relation between surface shape and surface tension, and combining solder joint surface gradient vector with its slant angle, in the end, the inspection of the solder joint surface has been transformed the inspection of plane of corresponding to the solder joint slant angle. After then, we introduce of the theoretic calculation method of illumination design, and use two specific examples (a single ring shape illumination and three color layers illumination) and their experimental results to show the feasibility.Finally, we introduce the computer-aided optical ray tracing theory in detail, especially the ray-tracing method used by TracePro software. Then we present a computer-aided illumination design method which combines the imaging system and illumination system as an integrated system, then we built an illumination imaging optical system model platform in the TracePro. On the basis of the platform, we analyze and contrast the uniformity of illumination and the data results, then we can find the best illumination.This dissertation presents the calculation method of illumination design and computer-aided illumination design, the main innovation of this paper is that we present a computer-aided illumination design method which combines the imaging system and illumination system as an integrated system, which provide a research direction for illumination design of AOI system.