1. Field of the Invention
The present invention relates to a displaying apparatus, and more particularly to a liquid crystal display and driving method thereof.
2. Background of the Related Art
Generally, a liquid crystal display (LCD) includes a thin film transistor (TFT) liquid crystal display (TFT-LCD) panel, a backlight unit, and a driver. The TFT-LCD panel may have degradations as follows: first, degradation of characteristic values from standard design due to process deviations; second, degradation due to dust, poor cleaning at a film surface, and the like; and, third, degradation of characteristic variations due to static electricity and breakdown of thin film transistors or liquid crystal cells.
One of the degradations occurring in a TFT-LCD panel is the irregularity of combining a first substrate with an opposed second substrate, which results in reducing the sharpness of a displayed video or in leaking light when failing to meet the design margin.
Reference will now be made in detail to an LCD according to a related art, examples of which are illustrated in the accompanying drawings.
FIG. 1 shows a layout of an LCD according to a related art.
Referring to FIG. 1, a liquid crystal display generally comprises a number of ‘m’ gate lines G1 to Gm arranged in a first direction with a constant interval between the gate lines; a number of ‘n’ data lines D1 to Dn arranged in a second direction perpendicular to the respective gate lines G1 to Gm with a constant interval between the data lines; a plurality of pixel electrodes (not shown in the drawing) formed as a matrix in pixel areas defined by the crossing gate and data lines respectively; and a plurality of thin film transistors for applying data signals supplied through the respective data lines to the respective pixel electrodes by being switched according to signals of the gate lines.
Further, a pair of driver integrated circuits (ICs) 14 and 15 are installed at the sides of the gate and data lines, respectively, so as to supply gate and data driving signals thereto. Namely, a pair of pads (not shown in the drawing) are formed at the ends of the gate and data lines to which the driver ICs are connected.
FIG. 2 shows cross-sectional views of the LCD taken along a line I–I′ in FIG. 1.
Referring to FIG. 2, a gate insulating layer 22 is formed on a first substrate 21. An nth data line 23 is patterned on the gate insulating layer 22. A passivation layer 24 made of an insulator is formed over an entire surface of the substrate including the nth data line 23. A transparent conductive layer of indium tin oxide (ITO) 25 for applying a voltage to the liquid crystal display is patterned on the passivation layer 24.
A black matrix 27 having predetermined spaces therein, is formed on an upper insulating substrate 26. A color filter layer 28 fills the spaces in the black matrix 27.
Unfortunately, the LCD according to the related art has some problems as follows.
The degree of alignment for the TFT and color filter substrates depends on the alignment tolerance (or margin) for combining (or assembling) the upper and lower substrates. Such combining margin is determined by the design of the respective substrates, for which precision of about several micrometers is required. Light leakage occurs at both lateral sides of the panel when the alignment between two substrates is deviated from the combining margin, thereby failing to provide desirable driving characteristics.
Namely, as shown in FIG. 2, there is no structure to block the light leakage at the right side of the nth data line 23. Therefore, light leakage occurs due to the transmitting light reaching the color filter layer.