Abstract
Several liquid crystal (LC) modes, such as twisted nematic, vertical alignment (VA), and in-plane switching, have been
in competition with each other in the LC display market. Among them, the VA mode has been widely used because of
the high contrast ratio. Since the LC molecules are aligned perpendicular to the substrate in the initial state, an excellent
dark state can be obtained at normal viewing direction. However, effective phase retardation of LC layer at oblique
viewing direction differs greatly from that at normal viewing direction. Thus, gamma distortion phenomenon occurs at
oblique view direction. To reduce the gamma shift in the VA mode at oblique viewing direction, multi-domain VA
modes were proposed. Although gamma shifts of these modes are smaller than that of the single domain VA mode, the
problems still remain. Recently, several technologies for 8-domain alignment have been proposed to decrease the gamma
shift at off-axis. However, additional driving circuits are required to realize the eight-domain structure. In this paper we
report technologies for the multi-domain VA mode with no additional driving circuits. By using the proposed
technologies, we can obtain the dual threshold voltage in each sub-pixel to realize the multi-domain VA mode with no
decrease of contrast ratio.
