A novel positioning method for optical automatic inspection of an LCD assembly process

In this paper a new marker alignment method is applied to the fabrication process of FPC positioning bonding, and sample comparison technology applied to the combined fabrication process of TFT-LCD. After the first linear regression method, filtration process, and second linear regression calculation, the central coordinate of the positioning marker can be obtained. The compensation method carries out sample point mapping compensation through parallelism or perpendicularity between the middle line and boundary line. This method can effectively avoid the positioning error produced by flaws in image taking process or poor image quality. This positioning method not only applies to the single image, but also could precisely position two images. In the future, it is expected this positioning method can be combined with positioning machine, and conduct positioning online.