Optical properties of electrophoretic image displays

Those variables determining the optical properties of one type of electrophoretic image display (EPID) are discussed in this paper. The working medium in the EPID with which this paper is concerned is a colloidal suspension of submicron pigment particles in a medium of matching specific gravity and contrasting color. The colloidal suspension is contained between two transparent electrodes. By changing the polarity of the applied voltage, the charged pigment particles may be moved to one or the other electrode. The effects of suspension composition, and the physical and chemical properties of the suspension components are discussed.