Flexible electroluminescent devices and systems

Abstract

An electroluminescent device is provided. The electroluminescent device includes an intrinsically conductive polymer layer having a thickness of from about 0.1 to about 3 microns and an elongation less than about 100%; and a phosphor layer having a thickness from about 20 microns to about 70 microns. The electroluminescent device demonstrates a loss of brightness of less than about 10% after undergoing repeated creasing, crushing, flexing, twisting, abrading, and/or stretching.

What is claimed is: 
     
         1 . A flexible electroluminescent device comprising a dielectric layer including a pigment and a binder, wherein the pigment to volume concentration is greater than the critical pigment volume concentration. 
     
     
         2 . The electroluminescent device according to  claim 1 , wherein the pigment comprises a ceramic with high dielectric constant. 
     
     
         3 . The electroluminescent device according to  claim 2 , wherein the ceramic is selected from one or more of barium titanate, cerium oxide, zinc oxide, titanium dioxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, tin oxide, indium-doped tin oxide, fluoride-doped tin oxide, manganese dioxide, tungsten trioxide, zirconium dioxide, strontium titanate, barium-strontium titanate, barium zirconate, barium zirconium titanate, lead zirconium titanate, and calcium copper titanate. 
     
     
         4 . The electroluminescent device according to  claim 1 , wherein the dielectric layer further comprises one or more of cure promoters, adhesion promoters, antioxidants, dispersion agents, and flame retardant agents. 
     
     
         5 . The electroluminescent device according to  claim 1 , wherein the binder is selected from one or more rubbers. 
     
     
         6 . The electroluminescent device according to  claim 5 , wherein the one or more rubbers are selected from one or more of olefinic rubbers, copolymers of butadiene and isoprene with ethylenically unsaturated monomers, copolymers of diene monomers, silicone rubbers, homopolymers, random copolymers, and block and graft copolymers of ethylene oxide, thermoplastic polyurethane rubbers, thermoplastic olefinic rubbers, and acrylate and methacrylate end-capped oligomers. 
     
     
         7 . The electroluminescent device according to  claim 1 , wherein the dielectric layer has a thickness from about 10 to about 20 microns. 
     
     
         8 . A flexible electroluminescent device comprising a rear electrode layer, a dielectric layer, a phosphor layer, a conductive layer comprising a conductive polymer, and a front electrode, wherein:
 the dielectric layer includes a pigment and a polymer, wherein the pigment to volume concentration is greater than the critical pigment volume concentration;   the conductive layer has a thickness of from about 0.3 to about 5 microns and an elongation less than about 100%;   the phosphor layer has a thickness from about 20 microns to about 70 microns; and   wherein each layer has a different individual elongation break point and layers with longer elongation break points support adjacent layers such that the device substantially maintains brightness after undergoing mechanical stress.   
     
     
         9 . A method of making a flexible electroluminescent device, the method comprising:
 depositing a flexible rear electrode layer on a flexible substrate;   depositing a flexible dielectric layer adjacent the rear electrode and opposite the substrate, wherein the dielectric layer includes at least a binder and a pigment and wherein the pigment to volume ratio is greater than the critical pigment volume concentration;   depositing a flexible phosphor layer having a thickness from about 20 microns to about 75 microns adjacent the dielectric layer and opposite the rear electrode; and   depositing a conductive layer having an elongation less than about 100% adjacent the phosphor layer and opposite the dielectric layer;   wherein each layer has a different individual elongation break point and layers with longer elongation break points support adjacent layers such that the device substantially maintains brightness after undergoing mechanical stress.