Electro-optic device comprising integrated conductive edge seal and a method of production of the same
Improved electro-optic devices are disclosed comprising an electrophoretic material layer comprising electrophoretic medium disposed between electrodes, and a conductive edge seal. The conductive edge seal is not only used to prevent ingress of moisture in the device, but also to electrically connect the electrodes. An improved method of producing an electro-optic device having conductive edge seal is also disclosed.
1. An electro-optic device having an active display area and comprising
a first light-transmissive electrode layer having an upper surface, a lower surface, and a peripheral surface, and comprising a first electrode contact location, wherein the upper surface of the first light-transmissive layer has a length and a width;
a backplane comprising a second electrode layer, wherein the second electrode layer comprises a second electrode contact location, wherein the backplane has an upper surface, a lower surface, and a peripheral surface, and wherein the upper surface of the backplane has a length and a width;
an electrophoretic material layer comprising an electrophoretic medium and having an upper surface, a lower surface, and a peripheral surface, wherein the upper surface of the electrophoretic material layer is defined by a perimeter having a length and a width,
a first adhesive layer having an upper surface, a lower surface, and a peripheral surface, wherein the upper surface of the first adhesive layer has a length and a width, wherein the upper surface of the first adhesive layer is in contact with the lower surface of the electrophoretic material layer, and wherein the lower surface of the first adhesive layer is in contact with the upper surface of the backplane;
a second adhesive layer having an upper surface, a lower surface, and a peripheral surface, wherein the upper surface of the second adhesive layer has a length and a width, wherein the upper surface of the second adhesive layer is in contact with lower surface of the first light-transmissive layer and the lower surface of the second adhesive layer is in contact with the upper surface of the electrophoretic material layer;
a conductive edge seal;
wherein the length and width of the upper surface of the first light-transmissive electrode layer and the length and width of the upper surface of the backplane are larger than the length and width of the perimeter of the upper surface of the electrophoretic material layer, the length and width of the upper surface of the first adhesive layers, and the length and width of the upper surface of the second adhesive layer;
wherein the first light-transmissive electrode layer and the backplane extend outwardly beyond the edges of the perimeter of the upper surface of the electrophoretic material layer and the edges of the first and the second adhesive layers, forming a groove that is defined by the outwardly extended first light-transmissive electrode layer, the peripheral surface of the second adhesive layer, the peripheral surface of the electrophoretic material layer, the peripheral surface of the first adhesive layer, and the outwardly extended backplane;
wherein the groove is filled with the conductive edge seal;
wherein the conductive edge seal electrically connects the first light-transmissive electrode at the first electrode contact location and the second electrode layer at the second electrode contact location; and
wherein at least part of the first electrode contact location and at least part of the second electrode contact location are outside the volume defined by a vertical extension of the perimeter of the upper surface of the electrophoretic material layer, resulting in the active display area of the device being substantially the same as the area of the upper surface of the electrophoretic material layer.
2. The electro-optic device of claim 1 , wherein the groove has height of from about 20 μm to about 150 μm.
3. The electro-optic device of claim 1 , wherein the groove has width of from about 0.3 mm to about 5 mm.
4. The electro-optic device of claim 1 , wherein the electrophoretic medium is compartmentalized in microcapsules.
5. The electro-optic device of claim 1 , wherein the electrophoretic medium is compartmentalized in microcells.
6. The electro-optic device of claim 1 , wherein the conductive edge seal is formed by an edge seal composition comprising a polymer selected from the group consisting of polyurethane, epoxy resin, polydimethylsiloxane, polyacrylate, polymethacrylate, polycarbonate, polyvinyl chloride, polystyrene-alkylene copolymer, polyamide, polyester, polystyrene, polyethylene, polypropylene, polyisobutylene, poly(ethylene terephthalate), poly(ethylene naphthalate), and mixtures thereof.
7. The electro-optic device of claim 1 , wherein the conductive edge seal is formed by an edge seal composition comprising conductive particles selected form the group consisting of carbon black particles, graphite, carbon nanotubes, metal particles, and mixtures thereof.
8. The electro-optic device of claim 1 , wherein the conductive edge seal is formed by an edge seal composition comprising a conductive polymer.
9. The electro-optic device of claim 1 , wherein the resistivity of the conductive edge seal is less than 10 kOhm·cm.