Liquid crystal display device

Abstract

A liquid crystal display device free from reduction of chromaticity and having a good image quality in comparison with a normally white mode semi-transmission liquid crystal display device even in a case of employing a normally black mode, able to secure a gap of a reflection portion able to suppress occurrence of defects, enabling a reduction of voltage, able to realize a reduction of power consumption, exhibiting a more natural color of the dark state of transmission, and able to improve the image quality, wherein a reflection portion and a transmission portion are provided in one pixel, a normally black mode which becomes a dark state when no voltage is supplied is employed, an orientation mode of the liquid crystals is a twist orientation, a polarization plate and one phase difference plate are provided on a viewing surface side, and a polarization plate is provided on a back surface side.

1 . A liquid crystal display device including a reflection portion and a transmission portion in one pixel and employing a normally black mode, wherein 
 an orientation mode of the liquid crystal is a twist orientation, a polarization plate and one phase difference plate are provided on a viewing surface side, and a polarization plate is provided on a back surface side.    
   
   
       2 . A liquid crystal display as set forth in  claim 1 , wherein a ratio dt/dr between a gap dt of said transmission portion and a gap dr of said reflection portion satisfies a relationship of 1.7≦dt/dr≦2.05.  
   
   
       3 . A liquid crystal display as set forth in  claim 1 , wherein the twist angle is 30 degrees to 60 degrees.  
   
   
       4 . A liquid crystal display as set forth in  claim 2 , wherein the twist angle is 30 degrees to 60 degrees.  
   
   
       5 . A liquid crystal display as set forth in  claim 1 , wherein at least one side in the shape of the boundary between said transmission portion and reflection portion is a shape other than a straight line.  
   
   
       6 . A liquid crystal display as set forth in  claim 2 , wherein at least one side in the shape of the boundary between said transmission portion and reflection portion is a shape other than a straight line.  
   
   
       7 . A liquid crystal display as set forth in  claim 4 , wherein at least one side in the shape of the boundary between said transmission portion and reflection portion is a shape other than a straight line.  
   
   
       8 . A liquid crystal display device including a reflection portion and a transmission portion in one pixel and employing a normally black mode, wherein 
 an orientation mode of the liquid crystal is a twist orientation, a polarization plate and one phase difference plate are provided on a viewing surface side, and a polarization plate is provided on a back surface side, wherein,    in said phase difference plate on the viewing surface side, when a refractive index of an extension direction of the phase difference plate is nx, a refractive index of a perpendicular direction to the extension direction is ny, a refractive index in a normal direction with respect to the phase difference plate surface is nz, and a value represented by the following equation is nz, Nz=(nx−nz)/(nx−ny) where, Nz satisfies the relationship of 0≦Nz≦0.5, wherein,    at least one side in the shape of the boundary between said transmission portion and reflection portion is a shape other than a straight line.