Liquid crystal display having wide viewing angle

Abstract

Saw-shaped protrusions, which are parallel to each other, are formed on the common electrode and the pixel electrode in two substrates. Protrusions in two substrates are arranged alternately and the bent portions of the saw-shaped protrusions are placed on the line transverse passing through the center of a pixel. Branches extend from the convex point of one saw-shaped protrusion toward the apex to the other saw-shaped protrusion, and another branch extend from the point where the protrusion meets the boundary of the pixel electrode toward the point where the boundary of the pixel electrode and the saw-shaped protrusion make an acute angle. A liquid crystal layer between two electrodes are divided to four regions where the directors of the liquid crystal layer have different angles when a voltage is applied to the electrodes, and then, wide viewing angle is obtained. In most regions, protrusions are formed straight and the protrusions have only obtuse angles at the bent points. Therefore, fast response time is shortened, disclination is removed and luminance increases.

What is claimed is:  
     
         1 . A liquid crystal display comprising: 
 a first substrate having an inner surface and an outer surface;    a first electrode on the inner surface of the first substrate;    a first protrusion on the first electrode;    a second substrate opposite the first substrate and having an inner surface and an outer surface;    a second electrode on the inner surface of the second substrate and located at a position corresponding to the first electrode; and    a second protrusion on the second electrode,    wherein boundaries of the first and the second protrusions are linear, curved or bent with an obtuse angle.    
     
     
         2 . The liquid crystal display of  claim 1 , wherein the first and the second protrusions form a substantially closed area.  
     
     
         3 . The liquid crystal display of  claim 2 , wherein the first and the second protrusions forming the substantially closed area are arranged symmetrically.  
     
     
         4 . The liquid crystal display of  claim 3 , wherein the width of the first and the second protrusions becomes larger form ends to centers of the first and the second protrusions.  
     
     
         5 . The liquid crystal display of  claim 3 , wherein width of the first and the second protrusions is 3-20 μm.  
     
     
         6 . The liquid crystal display of  claim 3 , wherein distance between the first and the second protrusions is 5-20 μm.  
     
     
         7 . The liquid crystal display of  claim 3 , further comprising: 
 a liquid crystal layer interposed between the first and the second substrates and having negative dielectric anisotropy;    a first and a second alignment layers on the first and the second electrodes respectively, the first and the second alignment layers aligning the long axes of liquid crystal molecules in the liquid crystal layer to be perpendicular to the first and the second substrates; and    a first and a second polarizers on the outer surfaces of the first and the second substrates, respectively.    
     
     
         8 . The liquid crystal display of  claim 7 , wherein the polarizing directions of the polarizers are perpendicular to each other.  
     
     
         9 . The liquid crystal display of  claim 8 , wherein the number of average axial directions of domains defined by the first and the second protrusions is four.  
     
     
         10 . The liquid crystal display of  claim 9 , wherein the average axial directions make 45°±10° with the poarizing directions of the first and the second polarizers.  
     
     
         11 . The liquid crystal display of  claim 10 , wherein the average axial directions of adjacent domains makes substantially right angle.  
     
     
         12 . The liquid crystal display of  claim 1 , wherein the second protrusion makes an oblique angle with boundaries of the second electrode, and the first protrusion comprises a first portion parallel to the second protrusion and a second portion formed at a position corresponding to the boundary of the second electrode where an angle between the second protrusion and the boundary of the second electrode is an acute angle.  
     
     
         13 . The liquid crystal display of  claim 12 , wherein an angle between the first and the second portions is an obtuse angle.  
     
     
         14 . The liquid crystal display of  claim 13 , wherein the first and the second portions are connected to each other.  
     
     
         15 . The liquid crystal display of  claim 14 , wherein the width of the second portion of the first protrusion decreases as goes from the connection with the first portion to the edge of the second portion.  
     
     
         16 . The liquid crystal display of  claim 12 , further comprising: 
 a third protrusion formed on the first electrode, wherein the first protrusion has a first bent portion and the third protrusion extending from the convex side of the first bent portion to the second protrusion; and    a fourth protrusion formed on the second electrode, wherein the second protrusion has a second bent portion and the fourth protrusion extending from the convex side of the second bent portion to the first protrusion.    
     
     
         17 . The liquid crystal display of  claim 16 , wherein an angle between the third protrusion and the first portion of the first protrusion and an angle between the fourth protrusion and the second protrusion are obtuse angles.  
     
     
         18 . The liquid crystal display of  claim 19 , wherein the third protrusion is connected to the first portion of the first protrusion, and the fourth protrusion is connected to the second protrusion.  
     
     
         19 . The liquid crystal display comprising: 
 a first substrate having an inner surface and an outer surface;    a first electrode on the inner surface of the first substrate;    a first protrusion on the first electrode;    a second substrate opposite the first substrate and having an inner surface and an outer surface;    a second electrode on the inner surface of the second substrate and located at a position corresponding to the first electrode; and    a second protrusion on the second electrode,    wherein the first and the second protrusions form a substantially closed area.    
     
     
         20 . A liquid crystal display comprising: 
 a first substrate having an inner surface and an outer surface;    a first electrode on the inner surface of the first substrate;    a first protrusion on the first electrode;    a second substrate opposite the first substrate and having an inner surface and an outer surface;    a second electrode on the inner surface of the second substrate and located at a position corresponding to the first electrode; and    a second protrusion on the second electrode,    wherein the width the first and the second protrusions becomes larger form ends to centers of the first and the second protrusions.    
     
     
         21 . A panel for a liquid crystal display comprising: 
 a transparent insulating substrate;    a pixel electrode formed on the substrate;    a saw shape protrusion formed on the pixel electrode; and    wires overlapping the protrusion.    
     
     
         22 . A panel for a liquid crystal display comprising: 
 a transparent insulating substrate;    a common electrode formed on the substrate;    a saw-shaped protrusion formed on the common electrode; and    a black matrix overlapping the protrusion.