Liquid crystal display with polymer aligned-film

Abstract

The arrangement of the moleculars of the optical activity compound such as polymer including azo-dye is changed by the polarization state of the pump beam applied to the polymer. The polymer is polyvinyl alcohol including methyl orange as azo-dye. The anisotropy of the molecular arrangement of the azo-dye is induced by the polarized incident beam and then the liquid crystal cell is made. Thereafter, the liquid crystal is inserted to the cell, aligning the liquid crystal. As the polarization of the pump beam advance from the linear polarization to the circular polarization, the moleculars of the methyl orange are exponentially increased at an axis parallel to the propagation direction of the pump beam and the moleculars of the methyl orange are exponentially decreased at an axis vertical to the propagation direction of the pump beam. The pretilt angle of the liquid crystal is exponentially increased as an electric field ratio of the major axis to that of the minor axis in the pump beam approaches 1, that is a circular polarization.

What is claimed is:  
     
         1 . A liquid crystal display comprising: 
 a first substrate;    a second substrate opposite said first substrate;    a polymer film including a azo-dye and formed on an opposite surface of said first substrate;    an alignment film formed on an opposite surface of said second substrate; and    a liquid crystal layer formed between said polymer film and said alignment film.    
     
     
         2 . The liquid crystal display as claimed in    claim 1   , wherein said polymer film is a polyvinyl alcohol including a methyl orange as said azo-dye.  
     
     
         3 . A method for aligning a polymer film, comprising the steps of: 
 providing a substrate;    forming said polymer film including an azo-dye on said substrate;    applying a pump beam having a predetermined polarization state to said polymer film, modifying an arrangement of a molecular of said polymer film.    
     
     
         4 . The method as claimed in    claim 3   , wherein said polymer film is a polyvinyl alcohol including a methyl orange as said azo-dye.  
     
     
         5 . The method as claimed in    claim 4   , wherein said predetermined polarization state is one of a circular polarization, an ellipse polarization and a linear polarization.  
     
     
         6 . The method as claimed in    claim 4   , wherein a number of said polymer film arranged in a first direction parallel to a proporgation direction of said pump beam and a number of said polymer film arranged in a second direction perpendicular to the proporgation direction of said pump beam are controlled according to an intensity scale of electric field of a major axis and an intensity scale of the electric field of a minor axis in said pump beam.  
     
     
         7 . The method as claimed in    claim 6   , wherein as a ratio of the electric field scale of the major axis and minor axis approaches 1, the number of said polymer film arranged in said first direction is exponetionally increased.  
     
     
         8 . The method as claimed in    claim 6   , wherein as a ratio of the electric field scale of the major axis and the electric field scale of the minor axis approaches 1, the number of said polymer film arranged in said second direction is exponetionally decreased.  
     
     
         9 . The method as claimed in    claim 6   , wherein a birefringence of said polymer film is exponentionally increased as a ratio of the electric field scale of the major axis and the electric field scale of the minor axis approaches 1.  
     
     
         10 . A method for aligning liquid crystal comprising the steps of: 
 providing a first substrate;    providing a second substrate opposite said first substrate;    forming said polymer film including an azo-dye on an opposite surface of said first substrate;    applying a pump beam having a predetermined polarization state to said polymer film, modifying an arrangement of a molecular of said polymer film; and    forming a liquid crystal layer between said first substrate and said second substrate.    
     
     
         11 . The method as claimed in    claim 10   , wherein said polymer film is a polyvinyl alcohol including a methyl orange as said Azo dye.  
     
     
         12 . The method as claimed in    claim 10   , wherein said predetermined polarization state is one of a circular polarization, an ellipse polarization and a linear polarization.  
     
     
         13 . The method as claimed in    claim 10   , wherein a number of said polymer film arranged in a first direction parallel to a proporgation direction of said pump beam and a number of said polymer film arranged in a second direction perpendicular to the proporgation direction of said pump beam are controlled according to an intensity scale of electric fields of a major axis and a minor axis in said pump beam.  
     
     
         14 . The method as claimed in    claim 13   , wherein as a ratio of the electric field scale of the major axis and the electric field scale of the minor axis approaches 1, the number of said polymer film arranged in said first direction is exponetionally increased.  
     
     
         15 . The method as claimed in    claim 13   , wherein as a ratio of the electric field scale of the major axis and the electric field of the minor axis approaches 1, the number of said polymer film arranged in said second direction is exponetionally decreased.  
     
     
         16 . The method as claimed in    claim 13   , wherein a birefringence of said polymer film is exponentionally increased as a ratio of the electric field scale of the major axis and the electric field scale of the minor axis approaches 1.  
     
     
         17 . The method as claimed in    claim 10   , wherein a pretilt angle in a liquid crystal of said liquid crystal layer is controlled according to said polarization state of said pump beam.  
     
     
         18 . The method as claimed in    claim 17   , wherein a pretilt angle in a liquid crystal of said liquid crystal layer is exponentionally increased as a ratio of the electric field scale of the major axis and the electric field scale of the minor axis approaches 1.  
     
     
         19 . The method as claimed in    claim 17   , wherein a pretilt angle in a liquid crystal of said liquid crystal layer is exponentionally increased as the molecular number of said polymer molecular arranged in said first direction is increased.  
     
     
         20 . The method as claimed in    claim 17   , wherein a pretilt angle in a liquid crystal of said liquid crystal layer is exponentionally decreased as the molecular number of said polymer arranged in said second direction is increased.  
     
     
         21 . The method as claimed in    claim 17   , wherein a pretilt angle in a liquid crystal of said liquid crystal layer is increased as a birefringence of said polymer film is increased.