Liquid-crystal panel of polymer dispersed type, method of manufacturing the same, and liquid crystal display apparatus

Abstract

A liquid-crystal panel comprises a pair of transparent glass substrates each being provided with an electrode. Between the glass substrates are disposed spacers for defining a space and a mixture of droplets of a liquid crystal having a mean diameter of 3.0 μm or less and of a photo-curing polymer. The edge portions of the glass substrates are sealed with a seal polymer. In curing the photo-curing polymer during the process of manufacturing the liquid-crystal panel, the dose of an ultraviolet ray is set to 500 mJ/cm 2 or more so as to reduce the diameters of the droplets of the liquid crystal, thereby preventing light leakage in the state without a voltage applied and improving the contrast. If the spacers are colored, the effect of preventing light leakage is increased. If the spacers are subjected to a surface treatment for rejecting the liquid crystal or composed of a polymer material of the same type as that of the photo-curing polymer, variations in diameter of the droplets of the liquid crystal can be prevented. With the structure, it becomes possible to provide a liquid-crystal panel in which light leakage in the black mode is reduced and which presents uniform and high-contrast display of images.

We claim:  
     
         1 . A liquid-crystal panel comprising: 
 a pair of substrates disposed so as to face each other, each being provided with an electrode for applying a voltage;    spacers dispersed in the space between said pair of substrates so as to hold said pair of substrates at a specified distance;    a polymer member filled in the space between said pair of substrates, said polymer member containing a crosslinkage-type polymer as its main component; and    droplets of a liquid crystal mixed with said polymer member and filled in the space between said pair of substrates, said droplets of the liquid crystal having a mean diameter of 3.0 μm or less.    
     
     
         2 . A liquid-crystal panel according to    claim 1   , wherein said spacers have the function of preventing the transmission of visible light.  
     
     
         3 . A liquid-crystal panel according to    claim 2   , wherein said spacers are colored.  
     
     
         4 . A liquid-crystal panel according to    claim 2   , wherein said spacers have a surface roughness sufficiently high to scatter visible light.  
     
     
         5 . A liquid-crystal panel according to    claim 1   , wherein the surface portions of said spacers have at least either of a scarce affinity with the droplets of the liquid-crystal and a large affinity with said polymer member.  
     
     
         6 . A liquid-crystal panel according to    claim 5   , wherein the surface portions of said spacers are treated so as to have the property of rejecting said liquid crystal.  
     
     
         7 . A liquid-crystal panel according to    claim 5   , wherein at least the surface portions of said spacers are composed of a polymer material of the same type as that of said polymer member.  
     
     
         8 . A liquid-crystal panel comprising: 
 a pair of substrates disposed so as to face each other, each being provided with an electrode for applying a voltage;    a polymer member filled in the space between said pair of substrates, said polymer member containing a crosslinkage-type polymer as its main component;    droplets of a liquid crystal mixed with said polymer member and filled in the space between said pair of substrates; and    spacers dispersed in the space between said pair of substrates so as to hold said pair of substrates at a specified distance, the surface portions of said spacers having at least either of a scarce affinity with the droplets of the liquid crystal and a large affinity with said polymer member.    
     
     
         9 . A liquid-crystal panel according to    claim 8   , wherein the surface portions of said spacers are treated so as to reject said liquid crystal.  
     
     
         10 . A liquid-crystal panel according to    claim 8   , wherein at least the surface portions of said spacers are composed of a polymer material of the same type as that of said polymer member.  
     
     
         11 . A liquid-crystal panel according to    claim 1   , wherein said polymer member is composed of a photo-curing polymer.  
     
     
         12 . A method of manufacturing a liquid-crystal panel comprising the steps of: 
 preparing in advance a pair of substrates each being provided with an electrode for applying a voltage and dispersing, on one of said pair of substrates, spacers for holding the substrates at a specified distance;    holding said substrate on which the spacers are dispersed and the other substrate so that they are opposed to each other with the spacers interposed therebetween, mixing a polymer member containing a crosslinkage-type polymer as its main component with a liquid crystal, and filling the mixture into the space between the substrates; and    promoting the crosslinkage of said polymer member, while causing a phase separation between said polymer member and said liquid crystal simultaneously, so as to separate said liquid crystal in droplets having a mean diameter of 3.0 μm or less.    
     
     
         13 . A method of manufacturing a liquid-crystal panel according to    claim 12   , wherein a photo-curing polymer is used as a material composing said polymer member and said polymer member is irradiated with light equal to or intenser than 500 mJ/cm 2  in the step of promoting the crosslinkage of said polymer member.  
     
     
         14 . A method of manufacturing a liquid-crystal panel comprising the steps of: 
 preparing in advance a pair of substrates each being provided with an electrode for applying a voltage and dispersing, on one of said pair of substrates, spacers for holding the substrates at a specified distance, the surface portions of said spacers having either a scarce affinity with droplets of a liquid crystal and a large affinity with a polymer member;    holding said substrate on which the spacers are dispersed and the other substrate so that they are opposed to each other with the spacers interposed therebetween, mixing said polymer member containing a crosslinkage-type polymer as its main component with a liquid crystal, and filling the mixture into the space between the substrates; and    promoting the crosslinkage of said polymer member, while causing a phase separation between said polymer member and said liquid crystal simultaneously.    
     
     
         15 . A method of manufacturing a liquid-crystal panel according to    claim 14   , further comprising the step of treating the surface portions of said spacers so that they have the property of rejecting said liquid crystal.  
     
     
         16 . A method of manufacturing a liquid-crystal panel according to    claim 15   , wherein, in the step of treating the surface portions of said spacers so that they have the property of rejecting the liquid crystal, a surface-active agent containing fluorine as its main component is adsorbed by the surfaces of the spacers.  
     
     
         17 . A method of manufacturing a liquid-crystal panel according to    claim 14   , wherein the spacers at least the surface portions of which are composed of a material of the same type as that of said polymer member are used.  
     
     
         18 . A liquid-crystal display apparatus comprising: a liquid-crystal panel; light radiating means for irradiating said liquid-crystal panel with light; a driving circuit for applying an electric signal to said liquid-crystal panel; and a displaying means for displaying the pattern of light outputted from said liquid-crystal panel, wherein said liquid-crystal panel comprises: 
 a pair of substrates disposed so as to face each other, each being provided with an electrode for applying a voltage;    spacers dispersed in the space between said pair of substrates so as to hold said pair of substrates at a specified distance;    a polymer member filled in the space between said pair of substrates, said polymer member containing a crosslinkage-type polymer as its main component; and    droplets of a liquid crystal mixed with said polymer member and filled in the space between said pair of substrates, said droplets of the liquid crystal having a mean diameter of 3.0 μm or less.    
     
     
         19 . A liquid-crystal display apparatus comprising: a liquid-crystal panel; light radiating means for irradiating said liquid-crystal panel with light; a driving circuit for applying an electric signal to said liquid-crystal panel; and a displaying means for displaying the pattern of light outputted from said liquid-crystal panel, wherein said liquid-crystal panel comprises: 
 a pair of substrates disposed so as to face each other, each being provided with an electrode for applying a voltage;    a polymer member filled in the space between said pair of substrates, said polymer member containing a crosslinkage-type polymer as its main component;    droplets of a liquid crystal mixed with said polymer member and filled in the space between said pair of substrates; and    spacers dispersed in the space between said pair of substrates so as to hold said pair of substrates at a specified distance, the surface portions of said spacers having at least either of a scarce affinity with the droplets of the liquid crystal and a large affinity with said polymer member.