Liquid crystal display device

Abstract

This invention offers a liquid crystal display device according to FFS technology, which is capable of sufficiently providing a common electrode with common electric potential and improving an aperture ratio of pixels to obtain a bright display. A pixel electrode is formed of a first layer transparent electrode. A common electrode made of a second layer transparent electrode is formed above the pixel electrode interposing an insulation film between them. The common electrode in an upper layer is provided with a plurality of slits. The common electrode extends over all the pixels in a display region. An end of the common electrode is disposed on a periphery of the display region and connected with a peripheral common electric potential line that provides a common electric potential Vcom. There is provided neither an auxiliary common electrode line nor a pad electrode, both of which are provided in a liquid crystal display device according to a conventional art.

1 . A liquid crystal display device comprising:
 a substrate comprising a display region and a periphery region surrounding the display region;   a plurality of pixels disposed in the display region, each of the pixels comprising a pixel electrode;   a peripheral common electric potential line provided with a common electric potential and disposed on the periphery region; and   a common electrode disposed on the pixel electrodes so as to cover the display region and so as to extend over and be in contact electrically with the peripheral common electric potential line,   wherein the common electrode has a plurality of slits at each of the pixels.   
     
     
         2 . The liquid crystal display device of  claim 1 , wherein an intersection angle between the peripheral common electric potential line and a longitudinal direction of the slits is larger than 45 degrees and equal to or smaller than 90 degrees. 
     
     
         3 . The liquid crystal display device of  claim 1 , further comprising a display signal line control circuit that provides the pixels with a display signal or a gate line control circuit that provides the pixels with a gate signal, wherein the peripheral common electric potential line surrounds the display region and the display signal line control circuit or the gate line control circuit is disposed between the display region and the peripheral common electric potential line. 
     
     
         4 . The liquid crystal display device of  claim 1 , further comprising a display signal line that provides the pixels with a display signal, wherein the peripheral common electric potential line is part of a wiring layer that is common to the display signal line. 
     
     
         5 . The liquid crystal display device of  claim 1 , further comprising a thin film transistor that is connected with the pixel electrode. 
     
     
         6 . A liquid crystal display device comprising:
 a substrate comprising a display region and a periphery region surrounding the display region;   a plurality of pixels disposed in the display region, each of the pixels comprising a pixel electrode having a plurality of slits;   a peripheral common electric potential line provided with a common electric potential and disposed on the periphery region; and   a common electrode disposed between the substrate and the pixel electrodes so as to cover the display region and so as to extend over and be in contact electrically with the peripheral common electric potential line.   
     
     
         7 . The liquid crystal display device of  claim 6 , wherein an intersection angle between the peripheral common electric potential line and a longitudinal direction of the slits is larger than 45 degrees and equal to or smaller than 90 degrees. 
     
     
         8 . The liquid crystal display device of  claim 6 , further comprising a display signal line control circuit that provides the pixels with a display signal or a gate line control circuit that provides the pixels with a gate signal, wherein the peripheral common electric potential line surrounds the display region and the display signal line control circuit or the gate line control circuit is disposed between the display region and the peripheral common electric potential line. 
     
     
         9 . The liquid crystal display device of  claim 6 , further comprising a display signal line that provides the pixels with a display signal, wherein the peripheral common electric potential line is part of a wiring layer that is common to the display signal line. 
     
     
         10 . The liquid crystal display device of  claim 6 , further comprising a thin film transistor that is connected with the pixel electrode.