Liquid crystal display device and method for manufacturing the same

A liquid crystal display device, comprising:

• a first substrate;
• a second substrate being opposite to said first substrate;
• a liquid crystal material hermetically sealed between said first substrate and said second substrate;
• a plurality of data lines, each of which a plurality of picture element electrodes are connected to respectively through a thin film transistor, said plurality of data lines and said plurality of picture element electrodes being formed on said first substrate;
• and
• a plurality of common electrode wiring lines, each of which a plurality of common electrodes are branched off from, said plurality of common electrode wiring lines and said plurality of common electrodes being formed on said first substrate,
• wherein each of said picture element electrodes and each of said common electrodes are located in such a manner as to be opposite to each other in an approximately planar direction, and
• wherein said plurality of data lines and said plurality of common electrode wiring lines are formed as thick conductive films, while said plurality of picture element electrodes and said plurality of common electrodes are formed as thin conductive films.

A method for manufacturing a liquid crystal display device, comprising:

• a thin film transistor substrate;
• an opposite substrate being opposite to said thin film transistor substrate;
• a liquid crystal material hermetically sealed between said thin film transistor substrate and said opposite substrate;
• a plurality of data lines, each of which a plurality of picture element electrodes are connected to respectively through a thin film transistor having a semiconductor layer region, a drain electrode and a source electrode, said plurality of data lines and said plurality of picture element electrodes making up a surface portion of said thin film transistor substrate;
• and a plurality of common electrode wiring lines, each of which a plurality of common electrodes are branched off from, said plurality of common electrode wiring lines and said plurality of common electrodes making up a surface portion of said thin film transistor substrate, wherein each of said picture element electrodes and each of said common electrodes are located in such a manner as to be opposite to each other in an approximately planar direction;
• said method comprising an opposite substrate forming processing and a thin film transistor forming processing,
• wherein said thin film transistor substrate forming processing comprises:
• a first step of forming a first conductive film on a transparent insulation substrate and then patterning said first conductive film to form simultaneously a plurality of lower-layer scanning lines making up respectively a lower portion of a scanning line serving as a gate electrode of said thin film transistor and a plurality of lower-layer common electrode wiring lines making up respectively a lower portion of said common electrode wiring line;
• a second step of forming a second conductive film on said transparent insulation substrate and then patterning said second conductive film to form simultaneously a plurality of upper-layer scanning lines making up respectively an upper portion of said scanning line and a plurality of upper-layer common electrode wiring lines making up respectively an upper portion of said common electrode wiring line;
• a third step of forming a plurality of said semiconductor layer regions via an inter-layer insulation film on said transparent insulation substrate, subsequently forming a third conductive film on said semiconductor layer, and then patterning said third conductive film to form simultaneously a plurality of lower-layer data lines making up respectively a lower portion of said data lines, a plurality of lower-layer drain electrodes making up respectively a lower portion of said drain electrode, and a plurality of lower-layer source electrodes making up respectively a lower portion of said source electrode;
• a fourth step of forming a fourth conductive film on said transparent insulation substrate and patterning said fourth conductive film to form simultaneously a plurality of upper-layer data lines making up respectively an upper portion of said data line, said plurality of said picture element electrodes, a plurality of upper-layer drain electrodes making up respectively an upper portion of said drain electrode, and a plurality of upper-layer source electrodes making up respectively an upper portion of said source electrode;
• and
• a fifth step of forming a protecting insulation film on said transparent insulation substrate, subsequently forming said oriented film on protecting insulation film by performing rubbing processing.