Dynamic stability of disclination lines in fringe-field switching mode with a wedge-shaped common electrode

We investigated the dynamic stability of disclination lines (DLs) generated near pixel edges for fringe-field switching (FFS) mode with a wedged shape common electrode. Actually, in the FFS mode with a liquid crystal (LC) of positive dielectric anisotropy, the LC dynamic is very unstable near pixel edges. There are strong field competitions between the adjacent active region and the pixel edge with a patterned slit at a bias voltage so that DLs are observed at the boundary. A reverse twist force near the pixel edges is strong at a high voltage and pushes DLs into the active region, resulting in a decreased transmittance in the panel. Thus, to solve this problem, another force is needed to make DLs remain near the pixel edges. In this study, we proposed an advanced FFS structure with a wedge-shaped common electrode. This structure produces a strong horizontal electric field due to the wedge-shaped common electrode extended near the data bus line. As a result, it can reduce portions of the reverse twist force in the panel and make DLs remain near the pixel edges. Also, it eliminates the distortion of pixel and data signals preventing the complete extension of a common electrode through the use of a wedge-shaped electrode.