1. Field of the Invention
This application claims the priority of Korean Patent Application No. 10-2006-044557 filed on May 18, 2006. The entire disclosure of application is incorporated herein by reference.
2. Description of the Related Art
This invention relates to a display panel, more specifically to a liquid crystal display device to improve image quality of the display. The liquid crystal display device includes a liquid crystal display panel which displays images based on light transmittance and a back-light assembly which provides light from the back side of the liquid crystal display panel.
Generally, the liquid crystal display device includes an upper polarizer attached on one side of the liquid crystal display panel and a lower polarizer attached on the other side of the liquid crystal display. The axes of the upper and the lower polarizers are formed perpendicular to each other.
The liquid crystal display device includes a first substrate which includes a thin film transistor and a pixel electrode, a second substrate which includes a color filter and a common electrode, and a liquid crystal layer arranged between the first substrate and the second substrate.
The pixel electrode is formed on the first substrate in the form of a matrix and has a rectangular shape in plan view. The common electrode is formed on the second substrate.
There are several kinds of operation modes in the liquid crystal display (e.g, a Twist Nematic (TN) mode, an In-Plan Switch (IPS) mode and a vertical alignment (VA) mode). Among theses operation modes, the VA mode has been employed more than other modes because the VA mode has better response speed.
Moreover, the VA mode has an improved viewing angle, for example, the PVA (Patterned Vertical Alignment) mode and the MVA (multi-domain vertical alignment) mode.
Each domain of the VA, PVA, MVA modes is aligned with a vertical or a horizontal direction along one side of the pixel electrode, and can be arranged to be at a 45-degree angle to the axis of the upper or lower polarizer.
When the domain is formed in a vertical or a horizontal direction along one side of the pixel electrode, most of the liquid crystals are arranged in a vertical direction in a domain by an electric field applied between the pixel electrode and the common electrode. The liquid crystals, however, positioned along both edges of the domain may be formed parallel to one of the axes of the lower or the upper polarizer.
Therefore, a dark area which does not allow light to penetrate may occur in one part of a pixel, thereby adversely affecting the quality of the display.
USPTO Backgrounds
USPTO Backgrounds