A high-speed high-resolution vision system for the inspection of TFT LCD

As the resolution and size of the TFT LCD are becoming higher and larger, respectively, its inspection system is required to have high resolution to detect dirt, impurities, cracks, etc. Also, in order to reduce the cost to inspect TFT LCD, the inspection time must be reduced. One of the most important subsystems in the TFT LCD inspection system is a vision system. But existing vision systems are insufficient to perform inspection tasks for a large TFT LCD during a short time. A high-speed high-resolution vision system for the inspection of large TFT LCD is proposed and developed in this paper. In order to have desired resolution over a large area, the proposed vision system can obtain image information through line scan cameras rather than expensive high-resolution area cameras. In order to reduce task time, this vision system consists of four high-performance digital signal processors (DSP). A parallel architecture and a pipeline algorithm are developed to reduce time to process image data of multiple line scan cameras. Based on these architectures and algorithm, an appropriate task will be assigned to each DSP, which results in reducing image-processing time. Through a PCI bus, the developed vision system can be connected to a personal computer (PC) that can provide a convenient user interface. Some experiments that show the performance of the developed vision system will be performed.