Liquid crystal display device and manufacturing method of liquid crystal display device

Abstract

The present invention provides a manufacturing method of a liquid crystal display device capable of achieving uniform alignment of monostable ferroelectric liquid crystal having spontaneous polarization, and provides the liquid crystal display device. The liquid crystal (monostable ferroelectric liquid crystal having spontaneous polarization) showing a phase sequence, either isotropic liquid phase—cholesteric phase—chiral smectic C phase, isotropic liquid phase—chiral nematic phase—chiral smectic C phase, or isotropic liquid phase—cholesteric phase—smectic A phase—chiral smectic C phase, from a high temperature side to a low temperature side, is sandwiched between two glass substrates having transparent electrodes and alignment films whose pretilt angle is not more than 2° and rubbing directions are parallel. In an alignment treatment which is performed to obtain a monostable state after heating the liquid crystal, an electric field with electric field strength of not less than 2 V/μm is applied in the vicinity of the transition temperature from a higher temperature phase than chiral smectic C phase to the chiral smectic C phase.

1 . A manufacturing method of a liquid crystal display device comprising two substrates each having an alignment film formed thereon and sandwiching a liquid crystal having spontaneous polarization; and electrodes, formed on the substrates, for applying a voltage to the liquid crystal, the liquid crystal showing a monostable state in which an average molecular axis of a director of liquid crystal molecules is aligned in a single direction when no voltage is applied, said method comprising the steps of: 
 rubbing each of the alignment films in the same direction;    heating the liquid crystal; and    applying an electric field generated by a DC voltage to said liquid crystal with electric field strength of more than 5 V/μm in a vicinity of a transition temperature from a higher temperature phase than chiral smectic C phase to the chiral smectic C phase in an alignment treatment which is performed to obtain the monostable state after heating,    wherein the liquid crystal shows a phase sequence, either isotropic liquid phase—cholesteric phase—chiral smectic C phase or isotropic liquid phase—chiral nematic phase—chiral smectic C phase, from a high temperature side to a low temperature side.    
   
   
       2 . (canceled)  
   
   
       3 . The manufacturing method of a liquid crystal display device of  claim 1 , wherein a temperature range of the vicinity of the transition temperature includes a temperature range of ±2° C. from the transition temperature.  
   
   
       4 - 5 . (canceled)  
   
   
       6 . The manufacturing method of a liquid crystal display device of  claim 1 , wherein a pretilt angle of said alignment films is not more than 2°.  
   
   
       7 . A liquid crystal display device manufactured by the manufacturing method of a liquid crystal display device of  claim 1 , comprising a back-light which is driven by a field-sequential color scheme, wherein a data-writing scanning voltage and a data-erasure scanning voltage are applied between the electrodes.  
   
   
       8 - 12 . (canceled)