Patent ID: 8107045
Filing Date: 2012-01-31
Classification: G02F,G09G

Abstract:
1. A color active matrix type vertically aligned mode liquid crystal display comprising: a scan signal wiring; a video signal wiring; a thin film transistor which is formed at an intersection of the scan signal wiring and the video signal wiring; a transparent pixel electrode connected to the thin film transistor element in which two or more long and slender slits are formed; an active matrix substrate having a liquid crystal alignment direction control electrode in a lower layer of the transparent pixel electrode formed via an insulator film; a color filter substrate facing the active matrix substrate; and an anisotropic liquid crystal layer having a negative dielectric constant sandwiched by the active matrix substrate and the color filter substrate; wherein in order to impress a voltage to liquid crystal molecules vertically aligned between the active matrix substrate and the color filter substrate, and to make the liquid crystal molecules tilt in different two or four directions, both of two kinds of following electrode structures are formed in one pixel of the active matrix substrate: (i) a transparent flat common electrode is used in the color filter substrate side, and for the transparent pixel electrodes facing the transparent flat common electrode in the active matrix substrate side, patterns having a shape of a long and slender slit are formed in such a way that the transparent pixel electrode is removed at a part of the slit, where the liquid crystal alignment direction control electrode is excluded in a lower layer of the slit; (ii) a transparent flat common electrode is used in the color filter substrate side, and for the transparent pixel electrode facing the transparent flat common electrode in the active matrix substrate side, patterns having a shape of a long and slender slit are formed, and a liquid crystal alignment direction control electrode having a shape substantially the same as that of the slit, and a dimension larger than that of the slits is formed in a lower layer of the slits via the insulator film where the transparent pixel electrode and the liquid crystal alignment direction control electrode in each pixel of the active matrix substrate are driven separately from one another; wherein a potential of the liquid crystal alignment direction control electrode currently placed in a lower layer of the slit of the transparent pixel electrode is set lower than a potential of the transparent pixel electrode when a potential of the transparent pixel electrode separated for every pixel on the active matrix substrate side is lower than a potential of the facing flat common electrode on the color filter substrate side; wherein a potential of the liquid crystal alignment direction control electrode placed in a lower layer of the slit of the transparent pixel electrode is set higher than a potential of the transparent pixel electrode when a potential of the transparent pixel electrode is higher than a potential of the facing flat common electrode of the color filter substrate side; and wherein the polarities of the potential of the transparent pixel electrode and the potential of the liquid crystal alignment direction control electrode are reversed to a polarity of a potential of the flat common electrode in the color filter substrate side every vertical scanning period.