Research And Implementation Of Overprint Detection Of Wick In The Heat Pipe High-power LED Source Based On Machine Vision

The high power LED light source with transparent glass as the basic material is a new type of light source which combines the principle of heat pipe and LED light source.The wick is a heat dissipation component which is made by overprinting glass microbeads ink on the phosphor dot array glass.This heat dissipation component is the core component of the heat pipe high-power LED light source.In the process of wick overprinting,the position deviation between the liquid absorption core mask and the phosphor dot array glass is still measured by a manual and visual method to complete overprinting.This method has low precision and poor stability,which can not meet the actual production demand.In order to solve this problem,a detection system based on machine vision technology is designed to measure the position deviation between the wick mask plate and the phosphor dot array glass.The system can accurately measure the position deviation between the wick mask plate and the phosphor dot array glass,which can solve the problem of low precision of wick printing.The main contents of this thesis are as follows:(1)Design of system scheme.Building a hardware system presents a method of using dual-industry camera to collect images of two of 90mm×70mm local printing area in 240mm×200mm overall printing area.This method not only improves the detection accuracy of the system,but also reflects the overall deviation to a large extent.Design a detection scheme of position deviation,and propose a method of using image processing technology to obtain the characteristic regions of the phosphor dot array glass and the wick mask,and then to obtain the position deviation based on the feature area.This method saves the printing materials,reduces the production cost and improves the detection efficiency.(2)Design of detection algorithm.Based on image processing technology,a detection algorithm to obtain the central coordinates of feature areas is proposed.The detection algorithm first preprocesses the collected color image,and then on the basis of the color mode RGB(red,green,blue)or HSV(hue,saturation,brightness)divides the color image into three channels.According to the characteristics of each channel,the best channel image is used for threshold segmentation.Then the morphological processing method and regional transformation processing method are used to extractthe feature region of the image.Finally,the central coordinates of the the characteristic region are obtained and converted to the actual physical coordinates.A deviation calculation method using the actual physical coordinates of the center of the characteristic region is proposed,which can accurately calculate the position deviation between the wick mask plate and the phosphor dot array glass.(3)System design and experimental analysis.On the platform of visual studio2019,the design of deviation detection software is completed,and the position deviation detection is realized.Finally,carry out 30 contrast experiments of wick overprinting.And the experimental results show that the average value overprint errors in X and Y directions are 0.03 mm and 0.04 mm respectively if using the deviation detection system of the wick overprinting.This average value overprint errors meet the actual production requirements that the wick overprint errors in X and Y directions should be all less than 0.05 mm.