Electrophoretic display utilizing phase separation of liquids

Abstract

An electrophoretic display is provided which includes first and second plates spaced apart to define a volume of space therebetween. The display also includes a first electrode positioned on the first plate, a second electrode positioned on the second plate, and an emulsion positioned within the space. The emulsion includes a non-polar phase forming a continuous phase of the emulsion and a polar phase forming a non-continuous phase of the emulsion. The polar phase of the emulsion is capable of forming droplets (reverse micelles or reverse emulsions) in the non-polar phase. The polar phase includes a dye which is insoluble in the non-polar phase, a polar solvent, and a detergent. Images are provided by the display by controlling the distribution of the polar phase droplets containing the dye in the non-polar liquid phase using an electric field formed between the first and second electrodes. A method is also provided for forming an image by electrophoretic phase separation of an emulsion. According to the method, an emulsion is formed between the non-polar phase which constitutes a continuous phase of the emulsion and the polar phase which constitutes a non-continuous phase of the emulsion. The polar phase forms droplets in the non-polar phase, the polar phase including a dye, a polar solvent, and a detergent. An image is formed in the display by applying an electric field across the emulsion which causes the polar phase droplets to redistribute themselves relative to the non-polar phase, redistribution including the coagulation of the polar phase in the non-polar phase as well as the separation of the polar phase from the non-polar phase.