1. Field of the Invention
The present invention relates to a liquid crystal display apparatus, and more particularly, to a liquid crystal display panel, a method for driving the same, and a liquid crystal display apparatus using the same which achieve a wide viewing angle by using a combination of gray scales of multiple domains and improved light transmittance and visibility.
2. Description of the Related Art
A liquid crystal display apparatus displays picture images by varying the light transmittance of a liquid crystal having dielectric anisotropy by use of an electric field. The liquid crystal display apparatus includes a liquid crystal display panel (hereinafter, referred to as “liquid crystal panel”) for displaying picture images through a liquid crystal cell matrix, and a driving circuit for driving the liquid crystal panel. In the liquid crystal display apparatus, wide viewing angle technology has been developed in order to overcome restrictions on a viewing angle in which images seem to be distorted according to the viewer's position watching a screen.
As a typical wide viewing angle technology, a multi-domain vertical alignment (VA) mode is used. In the VA mode, liquid crystal molecules having negative dielectric anisotropy are vertically aligned and perpendicularly driven by an electric field, thereby varying light transmittance. The VA mode becomes a normally black mode because light does not penetrate a polarizer which is at right angles to the alignment direction of the liquid crystal molecules when a voltage is not supplied. Especially, in the multi-domain VA mode, each sub-pixel is split into multiple domains to symmetrically align the liquid crystal molecules. Accordingly, a wide viewing angle is achieved by symmetrically generating a variation in light transmittance. The multiple domains are formed by using a protrusion or slit.
The VA mode using a protrusion forms the protrusion on upper and lower substrates and a voltage is applied in the state that the liquid crystal molecules form a symmetrical pre-tilt based on the protrusion. Then the liquid crystal molecules are driven in the pre-tilt direction, thereby forming the multiple domains. However, since the VA mode using the protrusion is weak in constraints of the liquid crystal molecules caused by the protrusion, light leakage occurs around the protrusion and visibility is low.
In the VA mode using a slit pattern, that is, a patterned vertical alignment (PVA) mode forms a slit in a common electrode of the upper and lower substrates and a pixel electrode and symmetrically drives the liquid crystal molecules on the basis of the slit by using a fringe field generated by the slit, thereby forming the multiple domains. In the PVA mode, however, the liquid crystal alignment is scattered by a lateral field generated from an edge of a sub-pixel having a rectangular shape and a phenomenon such as an edge texture occurs. Therefore, lateral visibility is reduced and light transmittance is low.
USPTO Backgrounds
USPTO Backgrounds