Liquid crystal display device and method of manufacturing the same

Abstract

In a liquid crystal display device comprising a first substrate 101 having a color filter, a second substrate 131 and a liquid crystal layer disposed therebetween, a color filter layer 110 is disposed on a protection film 108 of a thin film transistor formed on the first substrate 101 so as to be partitioned by a light shielding portion 111, and a common electrode 103 is disposed thereon. A pixel electrode to be connected to a source electrode 107 is disposed through a through hole formed in an overcoat layer (interlayer separation film) 112. On the first substrate below the color filter layer 110 are provided plural scan signal electrodes, plural video signal electrodes crossing the scan signal electrodes in a matrix form, plural thin film transistors formed in association with the crossing points between the electrodes. Each pixel is provided with a common electrode 103 which is connected over plural pixels through a common electrode wire to supply reference potential, and a pixel electrode 114 which is connected to the corresponding thin film transistor and disposed so as to confront the common electrode in the pixel area.

What is claimed is:  
     
         1 . A liquid crystal display device having a transparent first substrate, a transparent second substrate, and a liquid crystal layer and a color filter layer sandwiched between the first and second substrates, comprising: 
 said color filter layer disposed on said first substrate;    said liquid crystal layer disposed between said color filter layer and said second substrate;    plural scan signal electrodes, video signal electrodes for crossing said scan signal electrodes in a matrix form and plural thin film transistors formed in association with the crossing points between said scan signal electrodes and said video signal electrodes provided on said first substrate below said color filter layer;    at least one pixel formed in each of areas surrounded by said plural scan signal electrodes and said video signal electrodes: 
 each pixel provided with a common electrode which is connected over plural pixels through a common electrode wire to supply reference potential, and a pixel electrode which is connected to the corresponding thin film transistor and disposed so as to confront said common electrode in said pixel area; and  
 said common electrode and said pixel electrode disposed between said color filter layer and said liquid crystal layer;  
 wherein said common electrode and said pixel electrode are disposed in different layers through an interlayer separation film formed of a transparent insulating material, and  
 wherein electric field having a component which is dominantly parallel to said first substrate is produced in said liquid crystal layer by applying a voltage across said common electrode and said pixel electrode, and liquid crystal before the voltage is applied thereto is orientated substantially in parallel to said first substrate.  
   
     
     
         2 . The liquid crystal display device as claimed in    claim 1   , 
 wherein at least one of said common electrode and said pixel electrode is formed of a transparent conductive film.    
     
     
         3 . The liquid crystal display device as claimed in    claim 1   , 
 wherein said common electrode is formed on said color filter layer, said interlayer separation film is formed on said common electrode, and said pixel electrode is formed on said interlayer separation film.    
     
     
         4 . The liquid crystal display device as claimed in    claim 1   , 
 wherein an overcoat layer for protecting said color filter layer is formed on said color filter layer, said common electrode is formed on said overcoat layer, said interlayer separation film is formed on said common electrode, and said pixel electrode is formed on said interlayer separation film.    
     
     
         5 . The liquid crystal display device as claimed in    claim 1   , 
 wherein an overcoat layer for protecting said color filter layer is formed on said color filter layer, said pixel electrode is formed on said overcoat layer, said interlayer separation film is formed on said pixel electrode, and said common electrode is formed on said interlayer separation film.    
     
     
         6 . The liquid crystal display device as claimed in    claim 1   , 
 wherein said common electrode is formed in a grid shape so as to surround a pixel; said pixel electrode is disposed so as to traverse the pixel; and said common electrode commonly uses a part of said common electrode wire.    
     
     
         7 . The liquid crystal display device as claimed in    claim 1   , 
 wherein a plurality of said common electrodes and said pixel electrodes are arranged in the pixel.    
     
     
         8 . The liquid crystal display device as claimed in    claim 6   , 
 wherein said common electrode is formed so that the thin film transistor is hidden when viewed from the side of said second substrate.    
     
     
         9 . The liquid crystal display device as claimed in    claim 6   , 
 wherein said common electrode is formed so that said scan signal electrodes and said video signal electrodes are hidden when viewed from the side of said second substrate.    
     
     
         10 . A liquid crystal display device having a first substrate, a second substrate, and a liquid crystal layer and a color filter layer sandwiched between the first and second substrates, comprising: 
 said color filter layer disposed on said first substrate;    said liquid crystal layer disposed between said color filter layer and said second substrate;    plural scan signal electrodes, video signal electrodes for crossing said scan signal electrodes in a matrix form and plural thin film transistors formed in association with the crossing points between said scan signal electrodes and said video signal electrodes provided on said first substrate below said color filter layer;    at least one pixel formed in each of areas surrounded by said plural scan signal electrodes and said video signal electrodes;    each pixel provided with a common electrode which is connected over plural pixels through a common electrode wire to supply reference potential;    a pixel electrode which is connected to the corresponding thin film transistor disposed so as to confront said common electrode in said pixel area;    said common electrode and said pixel electrode disposed between said color filter layer and said liquid crystal layer;    said common electrode and said pixel electrode disposed in different layers through an interlayer separation film formed of a transparent insulating material;    wherein electric field having a component which is dominantly parallel to said first substrate is produced in said liquid crystal layer by applying a voltage across said common electrode and said pixel electrode, and    wherein liquid crystal before the voltage is applied thereto is orientated substantially vertically to said first substrate.    
     
     
         11 . The liquid crystal display device as claimed in    claim 10   , 
 wherein at least one of said common electrode and said pixel electrode is formed of a transparent conductive film.    
     
     
         12 . The liquid crystal display device as claimed in    claim 10   , 
 wherein said common electrode is formed on said color filter layer, said interlayer separation film is formed on said common electrode, and said pixel electrode is formed on said interlayer separation film.    
     
     
         13 . The liquid crystal display device as claimed in    claim 10   , 
 wherein an overcoat layer for protecting said color filter layer is formed on said color filter layer, said common electrode is formed on said overcoat layer, said interlayer separation film is formed on said common electrode, and said pixel electrode is formed on said interlayer separation film.    
     
     
         14 . The liquid crystal display device as claimed in    claim 10   , 
 wherein an overcoat layer for protecting said color filter layer is formed on said color filter layer, said pixel electrode is formed on said overcoat layer, said interlayer separation film is formed on said pixel electrode, and said common electrode is formed on said interlayer separation film.    
     
     
         15 . The liquid crystal display device as claimed in    claim 10   , 
 wherein said common electrode is formed in a grid shape so as to surround a pixel; said pixel electrode is disposed so as to traverse the pixel; and said common electrode commonly uses a part of said common electrode wire.    
     
     
         16 . The liquid crystal display device as claimed in    claim 10   , 
 wherein a plurality of said common electrodes and said pixel electrodes are arranged in the pixel.    
     
     
         17 . The liquid crystal display device as claimed in    claim 15   , 
 wherein said common electrode is formed so that the thin film transistor is hidden when viewed from the side of said second substrate.    
     
     
         18 . The liquid crystal display device as claimed in    claim 15   , 
 wherein said common electrode is formed so that said scan signal electrodes and said video signal electrodes are hidden when viewed from the side of said second substrate.    
     
     
         19 . The liquid crystal display device as claimed in    claim 10   , 
 wherein an optically negative compensation film and an optically positive compensation film are disposed between said first or second substrate and a polarizing plate to make anisotropy of refractive index of said liquid crystal layer and said compensation film isotropic.    
     
     
         20 . The liquid crystal display device as claimed in    claim 19   , 
 wherein a pre-tilt angles are beforehand formed along two directions in which liquid crystal molecules are felled when a voltage is applied.    
     
     
         21 . The liquid crystal display device as claimed in    claim 19   , 
 wherein a pre-tilt angle is beforehand formed in any one of directions in which liquid crystal molecules are felled when a voltage is applied.    
     
     
         22 . The liquid crystal display device as claimed in    claim 10   , 
 wherein liquid crystal contains an organic polymer compound.    
     
     
         23 . A method of manufacturing a liquid crystal display device comprising a first substrate, a second transparent second substrate, and a liquid crystal layer and a color filter layer sandwiched between said first and second substrates, comprising the steps of: 
 forming said color filter layer on said first substrate;    forming said liquid crystal layer between said color filter and said second substrate;    forming, on said first substrate below said color filter layer, plural scan signal electrodes, plural video signal electrodes crossing said scan signal electrodes in a matrix form, and plural thin film transistors in association with the crossing points between said scan signal electrodes and said video signal electrodes;    forming at least one pixel in each of areas surrounded by said plural scan signal electrodes and said plural video signal electrodes;    forming, in each pixel, a common electrode which is connected over plural pixels through a common electrode wire to supply reference potential, and a pixel electrode which is connected to the corresponding thin film transistor and disposed so as to confront said common electrode in said pixel area;    disposing said common electrode and said pixel electrode between said color filter layer and said liquid crystal layer, and disposing said common electrode and said pixel electrode in different layers through an interlayer separation film formed of transparent insulating material;    forming liquid crystal so as to be oriented substantially vertically to said first substrate when no voltage is applied across said common electrode and said pixel electrode; and    adding an organic material comprising monomers or olygomers into said liquid crystal, injecting said liquid crystal into the gap between said first substrate and said second substrate, and then polymerizing said organic material in said liquid crystal.    
     
     
         24 . A method of manufacturing a liquid crystal display device comprising a first substrate, a second transparent second substrate, and a liquid crystal layer and a color filter layer sandwiched between said first and second substrates, comprising the steps of: 
 forming said color filter layer on said first substrate;    forming said liquid crystal layer between said color filter and said second substrate;    forming, on said first substrate below said color filter layer, plural scan signal electrodes, plural video signal electrodes crossing said scan signal electrodes in a matrix form, and plural thin film transistors in association with the crossing points between said scan signal electrodes and said video signal electrodes;    forming at least one pixel in each of areas surrounded by said plural scan signal electrodes and said plural video signal electrodes;    forming, in each pixel, a common electrode which is connected over plural pixels through a common electrode wire to supply reference potential, and a pixel electrode which is connected to the corresponding thin film transistor and disposed so as to confront said common electrode in said pixel area;    disposing said common electrode and said pixel electrode between said color filter layer and said liquid crystal layer, and disposing said common electrode and said pixel electrode in different layers through an interlayer separation film formed of transparent insulating material; and    forming an optically negative compensation film and an optically positive compensation film between said first or second substrate and a polarizing plate, and forming, by a rubbing method, pretilt angles along two directions in which liquid crystal molecules are felled when a voltage is applied to said compensation films.    
     
     
         25 . A method of manufacturing a liquid crystal display device comprising a first substrate, a second transparent second substrate, and a liquid crystal layer and a color filter layer sandwiched between said first and second substrates, comprising the steps of: 
 forming said color filter layer on said first substrate;    forming said liquid crystal layer between said color filter and said second substrate;    forming, on said first substrate below said color filter layer, plural scan signal electrodes, plural video signal electrodes crossing said scan signal electrodes in a matrix form, and plural thin film transistors in association with the crossing points between said scan signal electrodes and said video signal electrodes;    forming at least one pixel in each of areas surrounded by said plural scan signal electrodes and said plural video signal electrodes;    forming, in each pixel, a common electrode which is connected over plural pixels through a common electrode wire to supply reference potential, and a pixel electrode which is connected to the corresponding thin film transistor and disposed so as to confront said common electrode in said pixel area;    disposing said common electrode and said pixel electrode between said color filter layer and said liquid crystal layer, and disposing said common electrode and said pixel electrode in different layers through an interlayer separation film formed of transparent insulating material;    forming liquid crystal so as to be oriented substantially vertically to said first substrate when no voltage is applied across said common electrode and said pixel electrode; and    forming an optically negative compensation film and an optically positive compensation film between said first or second substrate and a polarizing plate, and forming, by a rubbing method, a pretilt angle in any one of directions in which liquid crystal molecules are felled when a voltage is applied to said compensation films.    
     
     
         26 . A method of manufacturing a liquid crystal display device comprising a first substrate, a second transparent second substrate, and a liquid crystal layer and a color filter layer sandwiched between said first and second substrates, comprising the steps of: 
 forming said color filter layer on said first substrate;    forming said liquid crystal layer between said color filter and said second substrate;    forming, on said first substrate below said color filter layer, plural scan signal electrodes, plural video signal electrodes crossing said scan signal electrodes in a matrix form, and plural thin film transistors in association with the crossing points between said scan signal electrodes and said video signal electrodes;    forming at least one pixel in each of areas surrounded by said plural scan signal electrodes and said plural video signal electrodes;    forming, in each pixel, a common electrode which is connected over plural pixels through a common electrode wire to supply reference potential, and a pixel electrode which is connected to the corresponding thin film transistor and disposed so as to confront said common electrode in said pixel area;    disposing said common electrode and said pixel electrode between said color filter layer and said liquid crystal layer, and disposing said common electrode and said pixel electrode in different layers through an interlayer separation film formed of transparent insulating material;    forming liquid crystal so as to be oriented substantially vertically to said first substrate when no voltage is applied across said common electrode and said pixel electrode; and    forming an optically negative compensation film and an optically positive compensation film between said first or second substrate and a polarizing plate, and forming, by light irradiation, pretilt angles in two directions in which liquid crystal molecules are felled when a voltage is applied to said compensation films.    
     
     
         27 . A method of manufacturing a liquid crystal display device comprising a first substrate, a second transparent second substrate, and a liquid crystal layer and a color filter layer sandwiched between said first and second substrates, comprising the steps of: 
 forming said color filter layer on said first substrate;    forming said liquid crystal layer between said color filter and said second substrate;    forming, on said first substrate below said color filter layer, plural scan signal electrodes, plural video signal electrodes crossing said scan signal electrodes in a matrix form, and plural thin film transistors in association with the crossing points between said scan signal electrodes and said video signal electrodes;    forming at least one pixel in each of areas surrounded by said plural scan signal electrodes and said plural video signal electrodes;    forming, in each pixel, a common electrode which is connected over plural pixels through a common electrode wire to supply reference potential, and a pixel electrode which is connected to the corresponding thin film transistor and disposed so as to confront said common electrode in said pixel area;    disposing said common electrode and said pixel electrode between said color filter layer and said liquid crystal layer, and disposing said common electrode and said pixel electrode in different layers through an interlayer separation film formed of transparent insulating material;    forming liquid crystal so as to be oriented substantially vertically to said first substrate when no voltage is applied across said common electrode and said pixel electrode; and    forming an optically negative compensation film and an optically positive compensation film between said first or second substrate and a polarizing plate, and forming, by light irradiation, a pretilt angle in any one of directions in which liquid crystal molecules are felled when a voltage is applied to said compensation films.    
     
     
         28 . The method as claimed in    claim 26   , wherein the light irradiation to forming the pretilt angles is conducted on the surfaces of said compensation films from a slant direction.  
     
     
         29 . The method as claimed in    claim 28   , wherein the light irradiation for forming the pretilt angles is conducted by irradiating polarized light the surfaces of said compensation films from a slant direction.  
     
     
         30 . The method as claimed in    claim 27   , wherein the light irradiation for forming the pretilt angle is conducted on the surfaces of said compensation films from a slant direction.  
     
     
         31 . The method as claimed in    claim 28   , wherein the light irradiation for forming the pretilt angles is conducted by irradiating polarized light on the surfaces of said compensation films from a slant direction.  
     
     
         32 . A method of manufacturing a liquid crystal display device comprising the steps of: 
 forming a thin film on a transparent substrate;    forming a passivation film for protecting said thin film transistor;    successively coating, light-exposing, developing and baking plural photosensitive color resists to form a color filter;    forming a common electrode; and    forming an interlayer separation film of a transparent insulating film.    
     
     
         33 . A method of manufacturing a liquid crystal display device comprising the steps of: 
 forming a thin film on a transparent substrate;    forming a passivation film for protecting said thin film transistor;    successively coating, light-exposing, developing and baking plural photosensitive color resists to form a color filter;    forming an overcoat film for protecting said color filter;    forming a common electrode; and    forming an interlayer separation film of a transparent insulating film.    
     
     
         34 . The liquid crystal display device as claimed in    claim 33   , 
 wherein said common electrode is formed in a grid shape so as to surround a pixel; said pixel electrode is disposed so as to traverse the pixel; and said common electrode commonly uses a part of said common electrode wire.    
     
     
         35 . The liquid crystal display device as claimed in    claim 33   , 
 wherein a plurality of said common electrodes and said pixel electrodes are arranged in the pixel.    
     
     
         36 . The liquid crystal display device as claimed in    claim 34   , 
 wherein said common electrode is formed in a grid shape so as to surround a pixel; said pixel electrode is disposed so as to traverse the pixel; and said common electrode commonly uses a part of said common electrode wire.    
     
     
         37 . The liquid crystal display device as claimed in    claim 34   , 
 wherein a plurality of said common electrodes and said pixel electrodes are arranged in the pixel.    
     
     
         38 . The liquid crystal display device as claimed in    claim 35   , 
 wherein said common electrode is formed in a grid shape so as to surround a pixel; said pixel electrode is disposed so as to traverse the pixel; and said common electrode commonly uses a part of said common electrode wire.    
     
     
         39 . The liquid crystal display device as claimed in    claim 35   , 
 wherein a plurality of said common electrodes and said pixel electrodes are arranged in the pixel.