Liquid crystal display apparatus

Abstract

A liquid crystal display apparatus including a pair of substrates having electrodes and vertical alignment layers. A liquid crystal having a negative anisotropy of dielectric is inserted between the substrates. Each substrate has linearly arranged alignment control structures for controlling the alignment of the liquid crystal. The alignment control structures are formed in the form of projections or slits. Each alignment control structure is formed of a plurality of constituent units. In addition, means for forming a boundary of alignment of liquid crystal (singular point in director field) to control the liquid crystal located on the alignment control structures.

1 . A liquid crystal display device including a plurality of pixels, comprising: 
 a first substrate including a common electrode;    a second substrate including a plurality of pixel electrodes; and    a liquid crystal layer placed between said first substrate and said second substrate;    wherein    said first substrate includes a first substrate and a second structure, each of which is linearly arranged for controlling an alignment of a liquid crystal;    said second substrate includes a third structure and a fourth structure, each of which is linearly arranged for controlling an alignment of a liquid crystal;    said first structure and said second structure extend in different directions for each other in a pixel;    said third structure and said fourth structure extend in parallel with said first structure and said second structure, respectively, in said pixel; and    said first structure, said second structure, said third structure and said fourth structure extend in directions-different from a direction in which an edge of said pixel extends.    
   
   
       2 . The liquid crystal display device according to  claim 1 , wherein an angle between directions of said first structure and said second structure is approximately 90 degrees.  
   
   
       3 . The liquid crystal display device according to  claim 1 , wherein an additional structure, which branches off from said first structure and extends along an edge of said pixel, is formed on said first substrate.  
   
   
       4 . The liquid crystal display device according to  claim 1 , wherein an additional structure, which extends along an edge of said pixel, is formed on said first substrate, and an angle between said first structure and said additional structure is an obtuse angle.  
   
   
       5 . The liquid crystal display device according to  claim 1 , wherein said first structure and said second structure are continuously formed through a bend portion.  
   
   
       6 . The liquid crystal display device according to  claim 5 , wherein an additional structure, which branches off from said bend portion and extends on an obtuse angle side of said bend portion, is formed on said first substrate.  
   
   
       7 . The liquid crystal display device according to  claim 6 , wherein said additional structure extends along a bisector of an obtuse angle between said first structure and said second structure.  
   
   
       8 . The liquid crystal display device according to  claim 1 , wherein said first structure and said second structure are slits formed in said common electrode.  
   
   
       9 . The liquid crystal display device according to  claim 3 , wherein said additional structure is a slit formed in said common electrode.  
   
   
       10 . The liquid crystal display device according to  claim 6 , wherein said additional structure is a slit formed in said common electrode.  
   
   
       11 . The liquid crystal display device according to  claim 1 , wherein an angle between directions of said third structure and said fourth structure is approximately 90 degrees.  
   
   
       12 . The liquid crystal display device according to  claim 1 , wherein an additional structure, which branches off from said third structure and extends along an edge of said pixel, is formed on said second substrate.  
   
   
       13 . The liquid crystal display device according to  claim 1 , wherein an additional structure, which extends along an edge of said pixel, is formed on said second substrate, and an angle between said third structure and said additional structure is an obtuse angle.  
   
   
       14 . The liquid crystal display device according to  claim 1 , wherein said third structure and said fourth structure are continuously formed through a bend portion.  
   
   
       15 . The liquid crystal display device according to  claim 14 , wherein an additional structure, which branches off from said bend portion and extends on an obtuse angle side of said bend portion, is formed on said second substrate.  
   
   
       16 . The liquid crystal display device according to  claim 15 , wherein said additional structure extends along a bisector of an obtuse angle between said third structure and said fourth structure.  
   
   
       17 . The liquid crystal device according to  claim 1 , wherein said third structure and said fourth structure are slits formed in a pixel electrode.  
   
   
       18 . The liquid crystal display device according to  claim 12 , wherein said additional structure is a slit formed in a pixel electrode.  
   
   
       19 . The liquid crystal display device according to  claim 15 , wherein said additional structure is a slit formed in a pixel electrode.  
   
   
       20 . The liquid crystal display device according to  claim 10 , wherein said third structure and said fourth structure are slits formed in a pixel electrode.  
   
   
       21 . A liquid crystal display, comprising: 
 a first substrate having a first electrode;    a second substrate facing the first substrate and including a second electrode; and    a plurality of protrusions provided on at least one of the first and second substrates, the plurality of protrusions including a first protrusion having a branch extending along an edge of the first electrode.    
   
   
       22 . The liquid crystal display of  claim 21 , wherein the plurality of protrusions are provided on the second substrate.  
   
   
       23 . The liquid crystal display of  claim 22 , further comprising a plurality of apertures provided on the first substrate and including a first aperture.  
   
   
       24 . The liquid crystal display of  claim 23 , wherein an edge of the first aperture is oblique to the edge of the first electrode, and an end of the first aperture is located near the edge of the first electrode.  
   
   
       25 . The liquid crystal display of  claim 24 , wherein the branch extends from the first protrusion toward the end of the first aperture.  
   
   
       26 . The liquid crystal display of  claim 25 , wherein the branch makes an acute angle with the edge of the first aperture.  
   
   
       27 . The liquid crystal display of  claim 26 , wherein the width of the branch decreases as goes from the first protrusion to the end of the first aperture.  
   
   
       28 . A liquid crystal display, comprising: 
 a first substrate;    a common electrode formed on the first substrate;    a protrusion pattern formed on the common electrode;    a second substrate facing the first substrate;    a pixel electrode formed on the second substrate;    an aperture pattern formed on the pixel electrode and alternatively arranged with the protrusion pattern;    first and second polarizers attached to outer surfaces of the first and second substrates, respectively, polarizing directions of the first and second polarizers being perpendicular to each other,    wherein the protrusion pattern comprises a wedge-shaped pattern, the wedge-shaped pattern having a first branch extended along a first edge of the pixel electrode to an area where the aperture pattern meets the first edge with an acute angle.    
   
   
       29 . The liquid crystal display of  claim 28 , wherein a width of the first branch decreases as advancing to an end of the first branch.  
   
   
       30 . The liquid crystal display of  claim 29 , wherein the wedge-shaped pattern has a second branch extending from a convex point of the wedge-shaped pattern toward a second edge of the pixel electrode.  
   
   
       31 . The liquid crystal display of  claim 30 , wherein a width of the second branch decreases as advancing toward the second edge of the pixel electrode.  
   
   
       32 . The liquid crystal display of  claim 28 , wherein the protrusion pattern has a symmetrical cross section.  
   
   
       33 . The liquid crystal display of  claim 28 , wherein the protrusion pattern further comprises a line-shaped pattern arranged substantially parallel to the aperture pattern.  
   
   
       34 . The liquid crystal display of  claim 33 , wherein the line-shaped pattern has a branch extended along a second edge of the pixel electrode toward an area where the aperture pattern stops near the second edge.  
   
   
       35 . The liquid crystal display of  claim 34 , wherein a width of the branch of the line-shaped pattern decreases as advancing toward the area where the aperture pattern stops near the second edge.  
   
   
       36 . The liquid crystal display of  claim 28 , wherein the aperture pattern further comprises a branch aperture extending from the first edge of the pixel electrode towards a concave point of the wedge-shaped pattern.  
   
   
       37 . The liquid crystal display of  claim 36 , wherein a width of the branch aperture decreases as advancing toward the concave point of the wedge-shaped pattern.  
   
   
       38 . A liquid crystal display device according to  claim 1 , further comprising a pair of polarizers wherein, 
 polarization axes of said pair of polarizers cross at right angles.    
   
   
       39 . A liquid crystal display device according to  claim 1 , wherein 
 said first structure and said second structure extend symmetrically with respect to a line in a plane of said first substrate, and said third structure and said fourth structure extend symmetrically with respect to a line in a plane of said second substrate.    
   
   
       40 . A liquid crystal display device according to  claim 1 , wherein 
 said third structure and said fourth structure are slits formed in a pixel electrode and an end portion of each of said slits positioned inside said pixel electrode.