Liquid crystal display device and image display device

Abstract

A liquid crystal display device includes at least a common electrode line, a common electrode and a pixel electrode in each pixels, the common electrode line comprising a first common electrode line which extends in the extending direction of the gate lines and a second common electrode line which extends in the extending direction of the drain lines in the pixel region, the first common electrode line and the second common electrode line are spaced apart from each other by way of a first insulating film, the first common electrode line and the second common electrode line are connected via an opening portion formed in the first insulating film, and a second insulating film is formed over the opening portion.

What is claimed is:  
     
         1 . A liquid crystal display device comprising: 
 a liquid crystal layer and a color filter layer sandwiched between a first transparent substrate and a second transparent substrate;    a plurality of gate lines, a plurality of drain lines which cross the plurality of gate lines in a matrix array and thin film transistors formed corresponding to respective crossing points of the gate lines and the drain lines on the first substrate;    pixel regions each of which is surrounded by the neighboring gate lines and the neighboring drain lines;    each pixel includes at least a common electrode line, a common electrode and a pixel electrode;    wherein the common electrode line comprising a first common electrode line which extends in the extending direction of the gate lines and a second common electrode line which extends in the extending direction of the drain lines in the pixel region, the first common electrode line and the second common electrode line are spaced apart from each other by way of a first insulating film, the first common electrode line and the second common electrode line are connected via an opening portion formed in the first insulating film, and a second insulating film is formed over the opening portion.    
     
     
         2 . A liquid crystal display device according to  claim 1 , wherein the first common electrode line and the second common electrode line include at least the second insulating film between the common electrode in the pixel region, and the common electrode includes a portion which is arranged over the drain line by way of at least the second insulating film such that the portion has a width larger than a width of the drain line.  
     
     
         3 . A liquid crystal display device comprising: 
 a liquid crystal layer and a color filter layer sandwiched between a first transparent substrate and a second transparent substrate;    a plurality of gate lines, a plurality of drain lines which cross the plurality of gate lines in a matrix array and thin film transistors formed corresponding to respective crossing points of the gate lines and the drain lines on the first substrate;    pixel regions each of which is surrounded by the neighboring gate lines and the neighboring drain lines, each pixel includes at least a common electrode line and a pixel electrode,    wherein the liquid crystal display device comprising a first island-like electrode in the pixel region, includes an opening portion formed in a first insulating film which covers the first island-like electrode, includes a common electrode line which extends in the extending direction of the drain lines, wherein the first island-like electrode and the common electrode line are connected via the opening portion, the first is land-like electrode constitutes a lower electrode, and a second island-like electrode which is connected to a source of the thin film transistor and is formed on the first insulating film constitutes an upper electrode thus forming holding capacitance.    
     
     
         4 . A liquid crystal display device according to  claim 3 , wherein the liquid crystal display device includes the common electrodes which are constituted over an insulating film which covers the drain line over the first substrate, the common electrodes are connected in a matrix array between neighboring pixels, and the common electrodes include portions which have a width wider than a width of the drain lines over an insulating film which are applied onto the drain lines.  
     
     
         5 . A liquid crystal display device according to  claim 3 , wherein the insulating film of the holding capacitance is an inorganic insulating film which covers the gate line of the thin film transistor.  
     
     
         6 . A liquid crystal display device according to  claim 3 , wherein the first island-like electrode is constituted of a semiconductor layer of the thin film transistor and the insulating film of the holding capacitance includes at least a gate insulating film of the thin film transistor.  
     
     
         7 . A liquid crystal display device comprising: 
 a liquid crystal layer and a color filter layer sandwiched between a first substrate and a second substrate;    a plurality of gate lines, a plurality of drain lines which cross the plurality of gate lines in a matrix array and thin film transistors formed corresponding to respective crossing points of the gate lines and the drain lines on the first substrate;    pixel regions each of which is surrounded by the neighboring gate lines and the neighboring drain lines, wherein each pixel includes at least a common electrode line, a common electrode and a pixel electrode;    wherein the liquid crystal display device comprising a common electrode line which extends in the extending direction of the drain line as the common electrode line, includes an island-like metal pixel electrode which is connected to a source of the thin film transistor, wherein the pixel region includes an opening portion which is divided into 6 or more opening portions between the neighboring drain lines, at least 1 divided opening portion is arranged between the island-like metal pixel electrode and one of the neighboring drain lines, at least 2 divided opening portions are arranged between the common electrode line and the other of the neighboring drain lines, and at least 3 divided opening portions are arranged between the island-like metal pixel electrode and the common electrode line.    
     
     
         8 . A liquid crystal display device comprising: 
 a liquid crystal layer and a color filter layer sandwiched between a first substrate and a second substrate;    a plurality of gate lines, a plurality of drain lines which cross the plurality of gate lines in a matrix array and thin film transistors formed corresponding to respective crossing points of the gate lines and the drain lines on the first substrate;    pixel regions each of which is surrounded by the neighboring gate lines and the neighboring drain lines, wherein each pixel includes at least a common electrode line, a common electrode and a pixel electrode,    wherein the liquid crystal display device comprising a common electrode line which extends in the extending direction of the drain line as the common electrode line, includes an island-like metal pixel electrode which is connected to a source of the thin film transistor, wherein the pixel region includes an opening portion which is divided into 8 or more opening portions between the neighboring drain lines, at least 3 divided opening portions are arranged between the island-like metal pixel electrode and one of the neighboring drain lines, at least 2 divided opening portions are arranged between the common electrode line and the other of the neighboring drain lines, and at least 3 divided opening portions are arranged between the island-like metal pixel electrode and the common electrode line.    
     
     
         9 . A liquid crystal display device comprising: 
 a liquid crystal layer and a color filter layer sandwiched between a first substrate and a second substrate;    a plurality of gate lines, a plurality of drain lines which cross the plurality of gate lines in a matrix array and thin film transistors formed corresponding to respective crossing points of the gate lines and the drain lines on the first substrate;    pixel regions each of which is surrounded by the neighboring gate lines and the neighboring drain lines, each pixel includes at least a common electrode line, a transparent common electrode and a transparent pixel electrode;    wherein the transparent common electrode and the transparent pixel electrode are formed on a same layer above the drain lines, the liquid crystal display device includes a common electrode line which extends in the extending direction of the drain line as the common electrode line, a metal pixel electrode which is connected to a source of the thin film transistor, wherein the pixel region includes an opening portion which is divided into 6 or more opening portions between the neighboring drain lines, the metal pixel electrode is arranged below the transparent pixel electrode which is arranged closest to one drain line of the neighboring drain lines, the common electrode line is arranged close to the other drain line of the neighboring drain lines and below the transparent common electrode which is not arranged on the other drain line, and at least 1 or more transparent common electrode or 1 or more transparent pixel electrodes are arranged between the metal pixel electrode and the common electrode line.    
     
     
         10 . A liquid crystal display device comprising: 
 a liquid crystal layer and a color filter layer sandwiched between a first substrate and a second substrate;    a plurality of gate lines, a plurality of drain lines which cross the plurality of gate lines in a matrix array and thin film transistors formed corresponding to respective crossing points of the gate lines and the drain lines on the first substrate;    pixel regions each of which is surrounded by the neighboring gate lines and the neighboring drain lines, wherein each pixel includes at least a common electrode line, a transparent common electrode and a transparent pixel electrode;    wherein the liquid crystal display device comprising a metal pixel electrode which is arranged in a region sandwiched by the neighboring drain lines, includes a common electrode which extends in the extending direction of the drain line as the common electrode, and a distance between one of the neighboring drain lines and the metal pixel electrode, a distance between the metal pixel electrode and the common electrode and a distance between the common electrode and the other of the neighboring drain lines are set to approximately equal with respect to the number of division of the pixel region.    
     
     
         11 . A liquid crystal display device according to  claim 7 , wherein the liquid crystal display device includes a first common electrode line which extends in the extending direction of the gate lines as the common electrode line and a second common electrode line which extends in the extending direction of the drain line, and the first common electrode line and the second common electrode line are connected to each other via an opening portion of an insulating film in the pixel region.  
     
     
         12 . A liquid crystal display device according to  claim 10 , wherein the approximately equal distances with respect to the number of division of the pixel region are set to 3+3+2 in the liquid crystal display device in which the number of division of the a region between the neighboring drain signal lines is 8, are set to 3+3+4 in the liquid crystal display device in which the number of division of the a region between the neighboring drain signal lines is 10, and are set to 5+4+3 in the liquid crystal display device in which the number of division of the a region between the neighboring drain signal lines is 12.  
     
     
         13 . A liquid crystal display device comprising: 
 a liquid crystal layer and a color filter layer sandwiched between a first transparent substrate and a second transparent substrate;    a plurality of gate lines, a plurality of drain lines which cross the plurality of gate lines in a matrix array and thin film transistors formed corresponding to respective crossing points of the gate lines and the drain lines on the first substrate;    pixel regions each of which is surrounded by the neighboring gate lines and the neighboring drain lines, wherein each pixel includes at least a holding capacitance line and a pixel electrode;    wherein the liquid crystal display device comprising a first island-like electrode in the pixel region, includes an opening portion formed in a first insulating film which covers the first island-like electrode, includes a holding capacitance line which extends in the extending direction of the drain lines, wherein the first island-like electrode and the holding capacitance line are connected via the opening portion, the first island-like electrode constitutes a lower electrode, and a second island-like electrode which is connected to a source of the thin film transistor and is formed on the first insulating film constitutes an upper electrode thus forming holding capacitance.    
     
     
         14 . A liquid crystal display device according to  claim 13 , wherein the liquid crystal display device includes a second holding capacitance line which extends in the extending direction of the gate lines, and the second holding capacitance line and the holding capacitance line which extends in the extending direction of the drain lines are electrically connected via a through hole formed in the first insulating film.  
     
     
         15 . A liquid crystal display device according to  claim 13 , wherein the liquid crystal display device includes a second holding capacitance line which extends in the extending direction of the gate lines and the second holding capacitance line also functions as the first island-like electrode.  
     
     
         16 . A liquid crystal display device comprising: 
 a liquid crystal layer and a color filter layer sandwiched between a first transparent substrate and a second transparent substrate;    a plurality of gate lines, a plurality of drain lines which cross the plurality of gate lines in a matrix array and thin film transistors formed corresponding to respective crossing points of the gate lines and the drain lines on the first substrate;    pixel regions each of which is surrounded by the neighboring gate lines and the neighboring drain lines, wherein each pixel includes a common electrode line, a transparent common electrode and a pixel electrode,    wherein an insulating film is formed over the gate line, the transparent common electrode is formed over the insulating film and has a region which covers the insulating film and has a width which is larger than a width of the gate line, and the transparent electrode line having the width wider than the width of the gate line plays a role of a black matrix in the liquid crystal display device.    
     
     
         17 . A liquid crystal display device according to  claim 16 , wherein the transparent electrode line having the width wider than the width of the gate line also covers a semiconductor layer of the thin film transistor.  
     
     
         18 . A liquid crystal display device according to  claim 16 , wherein the insulating film is an organic insulating film made of acrylic resin or the like.  
     
     
         19 . A liquid crystal display device according to  claim 1 , wherein the common electrode and the pixel electrodes are formed of a transparent electrode and both electrodes are formed as an uppermost layer of the first substrate below an orientation film.  
     
     
         20 . A liquid crystal display device according to  claim 1 , wherein the liquid crystal display device is a lateral electric field type liquid crystal display device.  
     
     
         21 . A liquid crystal display device according to  claim 1 , wherein a semiconductor layer of the thin film transistor is formed of polysilicon.  
     
     
         22 . An image display device which is used as a liquid crystal television comprising the liquid crystal display device according to  claim 1 .  
     
     
         23 . An image display device which is used as a liquid crystal monitor comprising the liquid crystal display device according to  claim 1 .  
     
     
         24 . An image display device which is used as an integral type personal computer comprising the liquid crystal display device according to  claim 1.