Patent ID: 8400600

Claim:
A liquid crystal display device, comprising: a gate line on a substrate; a data line crossing the gate line with a gate insulating film therebetween, wherein the crossing gate and data lines define a pixel area; a thin film transistor including a gate electrode connected to the gate line, a source electrode connected to the data line, a drain electrode opposite the source electrode and a semiconductor layer defining a channel between the source electrode and the drain electrode; a common line on the substrate substantially parallel to the gate line; a common electrode connected to the common line and in the pixel area; and a pixel electrode connected to the drain electrode and formed in the pixel area, wherein a horizontal electric field is applied between the pixel electrode and the common electrode, wherein the gate line, the common line and the common electrode are formed of a first conductive layer group having at least double conductive layers, and the data line, the source electrode, the drain electrode and the pixel electrode are formed of a second conductive layer group having at least double conductive layers, and a protective film on an entire surface of the gate insulating film except where the second conductive layer group is formed, the protective film interfacing with the second conductive layer group; wherein a portion of the common electrode is formed of a lowermost layer of the first conductive layer group; wherein a portion of the common electrode formed of the lowermost layer of the first conductive layer group is exposed via a transmitting hole passing through the gate insulating film to be in contact with the protective film; and wherein upper surfaces of the source and drain electrodes are flush with an upper surface of the protective film between the source and drain electrodes so that the upper surfaces of the source and drain electrodes and the upper surface of the protective film form a single horizontal upper surface.