Display device including formable transparent conductive films with metal nanowires

Abstract

A formable transparent conductive film are described that comprise a sparse metal conductive layer, a thermoplastic polymer substrate supporting the sparse metal conductive layer, a viscoelastic polymer with a thickness from about 15 microns to about 150 microns over the sparse metal conductive layer. A layered film structure can be formed that is suitable for contouring on the surface of a three dimensional object without unacceptable increases in sheet resistance and with good optical transparency and low haze. The formable films can be placed into a frozen configuration bent 90 degrees with a radius of curvature of no more than about 5 centimeters while exhibiting a surface resistance of no more than about 500 ohms/sq. with a total transmittance with respect to visible light of at least about 80%.

What is claimed is: 
     
         1 . A display device comprising a three dimensional surface, light emitting elements positioned to emit light from the surface and a transparent electrically conductive film covering at least a portion of the light emitting elements, the transparent electrically conductive film comprising a sparse metal conductive layer supported by a thermoplastic polymer substrate, wherein the transparent electrically conductive film is formed to span an edge of the surface to cover at least portions of two angled surfaces with an angle relating the surfaces of at least about 60 degrees such that the film has a portion with a radius of curvature of no more than about 5 centimeters, and wherein the film exhibits a surface resistance of no more than about 500 ohms/sq. with a total transmittance with respect to visible light of at least about 80%. 
     
     
         2 . The display device of  claim 1  wherein the transparent electrically conductive film further comprises a viscoelastic polymer with a thickness from about 15 microns to about 150 microns over the sparse metal conductive layer. 
     
     
         3 . The display device of  claim 1  wherein the sparse metal conductive layer comprises a nanostructured metal network. 
     
     
         4 . The display device of  claim 1  wherein the sparse metal conductive layer comprises fused metal nanowires. 
     
     
         5 . The display device of  claim 1  wherein the sparse metal conductive layer comprises fused silver nanowires. 
     
     
         6 . The display device of  claim 1  wherein the sparse metal conductive layer comprises a polymer binder. 
     
     
         7 . The display device of  claim 2  further comprising a cured overcoat layer between the sparse metal conductive layer and the viscoelastic polymer, wherein the overcoat layer has a thickness from about 50 nm to about 50 microns. 
     
     
         8 . The display device of  claim 2  further comprising a cap polymer layer comprising a thermoplastic polymer over the viscoelastic layer. 
     
     
         9 . The display device of  claim 1  wherein the transparent electrically conductive film exhibits a sheet resistance of no more than about 250 ohms/sq., a sheet resistance after stretching to 20% strain of no more than about 1000 ohms/sq. and a sheet resistance after bending 180 degrees with a radius of curvature of 0.5 mm of no more than about 1000 ohms/sq. with a total transmittance of visible light of at least about 88%. 
     
     
         10 . The display device of  claim 1  wherein the sparse metal conductive layer is patterned to form regions of low electrical resistance and regions of electrical resistance at least 100 times more resistive than the regions of low electrical resistance. 
     
     
         11 . The display device of  claim 1  wherein the transparent electrically conductive film exhibits a surface resistance of no more than about 150 ohms/sq. with a total transmittance with respect to visible light of at least about 85%. 
     
     
         12 . The display device of  claim 1  wherein the transparent electrically conductive film exhibits a surface resistance of no more than about 100 ohms/sq. with a total transmittance with respect to visible light of at least about 87%. 
     
     
         13 . A method for forming a device with a display and a formed transparent electrically conductive film, the method comprising:
 securing a flexible transparent electrically conductive film comprising a sparse metal conductive layer supported by a thermoplastic polymer substrate around an edge of the device with the flexible transparent electrically conductive film extending around the edge in contact with at least portions of two surfaces with an angle relating the surfaces of at least about 60 degrees to form a formed transparent electrically conductive film having a surface resistance of no more than about 500 ohms/sq with a total transmittance with respect to visible light of at least about 80%.   
     
     
         14 . The method of  claim 13  wherein the flexible transparent electrically conductive film further comprises a viscoelastic polymer with a thickness from about 15 microns to about 150 microns over the sparse metal conductive layer. 
     
     
         15 . The method of  claim 13  wherein the display comprises a three dimensional surface having a contoured shape, and the formed transparent electrically conductive film is formed by heating the flexible transparent electrically conductive film to conform to the contoured shape. 
     
     
         16 . The method of  claim 15  wherein heating comprises heating the flexible transparent electrically conductive film above a glass transition temperature of the thermoplastic polymer substrate. 
     
     
         17 . The method of  claim 13  wherein the formed transparent electrically conductive film exhibits a sheet resistance of no more than about 250 ohms/sq., a sheet resistance after stretching to 20% strain of no more than about 1000 ohms/sq. and a sheet resistance after bending 180 degrees with a radius of curvature of 0.5 mm of no more than about 1000 ohms/sq. with a total transmittance of visible light of at least about 88%. 
     
     
         18 . The method of  claim 13  wherein the sparse metal conductive layer is patterned to form regions of low electrical resistance and regions of electrical resistance at least 100 times more resistive than the regions of low electrical resistance. 
     
     
         19 . The method of  claim 13  wherein the formed transparent electrically conductive film exhibits a surface resistance of no more than about 150 ohms/sq. with a total transmittance with respect to visible light of at least about 85%. 
     
     
         20 . The method of  claim 13  wherein the formed transparent electrically conductive film exhibits a surface resistance of no more than about 100 ohms/sq. with a total transmittance with respect to visible light of at least about 87%.