Color display device

Abstract

The present invention provides a reflective color display device which can display multiple color states, without the disadvantages associated with previously known color display devices. The display fluid of the present invention comprises (a) black and white electrophoretic particles which are oppositely charged and (b) charged color-generating particles having photonic crystal characteristics, all of which are dispersed in a solvent or solvent mixture.

What is claimed is: 
     
         1 . A display fluid comprising:
 (a) black and white electrophoretic particles which are oppositely charged, and   (b) charged color-generating particles having photonic crystal characteristics;   
       all of which are dispersed in a solvent or solvent mixture. 
     
     
         2 . The fluid of  claim 1 , wherein all of the color-generating particles are either positively or negatively charged. 
     
     
         3 . The fluid of  claim 1 , wherein the charged color-generating particles have electrical polarization characteristics. 
     
     
         4 . The fluid of  claim 1 , wherein the solvent or solvent mixture has electrical polarization characteristics. 
     
     
         5 . The fluid of  claim 1 , wherein both the color-generating particles and the solvent or solvent mixture have electrical polarization characteristics. 
     
     
         6 . The fluid of  claim 1 , wherein the color-generating particles are formed of silicon (Si), titanium (Ti), barium (Ba), strontium (Sr), iron (Fe), nickel (Ni), cobalt (Co), lead (Pb), aluminum (Al), copper (Cu), silver (Ag), gold (Au), tungsten (W), molybdenum (Mo), or a compound thereof. 
     
     
         7 . The fluid of  claim 1 , wherein the color-generating particles are formed of polymer materials such as PS (polystyrene), PE (polyethylene), PP (polypropylene), PVC (polyvinyl chloride), or PET (polyethylene terephthalate). 
     
     
         8 . The fluid of  claim 1 , wherein the color-generating particles are formed by coating particles or a cluster having no electric charge with a material having electric charges. 
     
     
         9 . The fluid of  claim 3 , the color-generating particles include a material which is electrically polarized with any one of electronic polarization, ionic polarization, interfacial polarization or rotational polarization due to asymmetrical charge distribution of atoms or molecules as an external electric field is applied. 
     
     
         10 . The fluid of  claim 1 , wherein the color-generating particles include a ferroelectric material. 
     
     
         11 . The fluid of  claim 1 , wherein the color-generating particles include a superparaelectric material. 
     
     
         12 . The fluid of  claim 1 , wherein the color-generating particles include a material having a perovskite structure. 
     
     
         13 . The fluid of  claim 4 , wherein the solvent is water, trichloroethylene, carbon tetrachloride, di-iso-propyl ether, toluene, methyl-t-bytyl ether, xylene, benzene, diethyl ether, dichloromethane, 1,2-dichloroethane, butyl acetate, iso-propanol, n-butanol, tetrahydrofuran, n-propanol, chloroform, ethyl acetate, 2-butanone, dioxane, acetone, methanol, ethanol, acetonitrile, acetic acid, dimethylformamide, dimethyl sulfoxide or propylene carbonate. 
     
     
         14 . A method for generating a full spectrum of colors, comprising applying an electric field to the display fluid of  claim 1  to control the inter-particle distances of the color-generating particles. 
     
     
         15 . The method of  claim 14 , wherein the intensity of the colors displayed is controlled by adjusting locations of the black and white electrophoretic particles or mixing levels of the black and white particles.