Printed circuit board (PCB) is a substrate for electronic parts assembly, manufacturing quality of PCB plate directly affects the reliability of electronic products, so the PCB known as the "mother of the modern electronics industry". Along with the electronic assembly to the PCB hybrid technology with higher density, smaller size of the depth development, checking means only depend on the traditional functional testing and manual visual inspection, has been unable to meet the scale of modern PCB requirements of industrial production. At present, a yield of general PCB is still around 60% to 70%, in order to reduce the number of defects in circuit board into the next process, the key equipment - automatic optical detection in PCB detection (AOI) system, the demand is also growing.
Recently, the first domestic manufacturer of automatic optical inspection system of Zhejiang Ou Wei Technology Co. Ltd. with its own logical mathematical model and image matching technology, printed circuit board automatic optical inspection instrument for successful R & D, broke the Israeli Orbotech and screen in the field of monopoly, make our country into the 30 micron era in the detection field of automatic light vision. The future of China’s printed circuit board production enterprises will no longer consume artificial expensive artificial visual medium detection, also do not have to worry about product quality qualified rate, more don’t have to worry about foreign optical detection equipment cost high, the price compared with foreign products fell 50%.
Automatic optical inspection system is through the high definition camera surface graphics, graphics PCB extraction by digital conversion, logic and graph matching feature points, lines, shape comparison, logical defect determination and extraction of the technical process to realize the PCB pattern on the surface defect detection.
As the core of the whole system, how to determine the accurate mathematical algorithms of point defects software and the core is the biggest problem, defect detection software is used for traditional lattice image contrast technique (P2P), detection need the original image sharpness is high, i.e. the optical image acquisition equipment definition to determine overall performance of equipment, application of this technology is directly caused by the high cost of the equipment and poor performance, and can not meet the actual production technology leapfrogging development requirements. Therefore Ou Wei technology proposed by the six new algorithms that subpixel contour matching concept subpixel contour extraction, contour extraction, CAM data precision alignment algorithm, regional tailoring and deformation, edge matching, defect classification and filtering, and successfully applied to the new equipment. Sub pixel profile alignment technology can optimize the extraction quality of original image, image edge accurately, simplify the minimum logic judgment unit pixel demand, an image clarity the original 50 μ m, 30 micron to fine level optimization
The development of the integrated high-speed linear array camera design system, linear encoder feedback device, ultra high speed stroboscopic light source, scanning imaging device separated zoom PCB board; the negative pressure positioning rapid loading and unloading platform; special precise motion control card and a series of new technology achievements. In the software architecture operation as far as possible which is simple, easy to use, avoids the complicated operation and parameter adjustment.
In the product development, obtained 2 invention and 4 utility model patents, 4 software copyrights, and supported by the Ministry of science and technology innovation fund for small and medium enterprises, won the 2012 annual Wenzhou city science and technology progress award. The products have been exported to Russia, India, South Korea and Taiwan and other countries and regions, in recent years, realize the output value over 100 million yuan.
