Using image analysis techniques to enhance TFT-LCD manufacturing yield through timely detection of PI alignment layer defects

Abstract

This study aims to develop a solution to the manufacturing process defects of thin-film transistor liquid crystal display (TFT-LCD) panels. Specifically, it focuses on online image analysis for detecting uneven coatings of the polyimide (PI) alignment layers, which are crucial in the TFT-LCD manufacturing process. The PI solution is typically applied to a substrate surface using an array of nozzles via droplet deposition. During this process, nozzle clogging can cause a series of defects in the form of spots on the alignment layer. These defects impact the alignment of liquid crystal molecules in the TFT-LCD, leading to decreased display quality, reduced visibility, uneven brightness, and compromised image details. If suspected signs of alignment layer spots are identified, the image analysis technology assists online inspectors with prompt responses to minimize TFT-LCD production errors. The results of this study demonstrate timely detection of alignment layer spots, prevention of their progression, and significant reduction of the time required for manual inspection to improve manufacturing yield. This newly developed approach is applicable to not only TFT-LCD production monitoring but also smart display panel manufacturing, thereby providing significant value in high-volume and large-area panel fabrication processes.