Color Electrophoretic Image Display Based on Movement of Particles in Color Insulating Liquid

Abstract

Black and white Electrophoretic Image Display (EPID) is already commercially available as an electronic document viewer, sub-display in cell-phone, etc. Furthermore, Color EPID device coupled with color filters is demonstrated. In this system, there is a problem of the decreasing of the reflection light intensity of white view in order to pass a filter. We have proposed novel Color EPID based on the movement of white and black particles in a colored insulating liquid. We used two kinds of white particles, such as non-electrophoretic polymer particles and negatively charged titanic oxide particles. Non-electrophoretic white particles are used for light scattering and increasing the intensity of the color insulating liquid's luminosity. The display cell is consisted of one common transparent electrode coated on the top grass substrate and two driving electrodes coated on the bottom grass substrate. The movement of charged particles is controlled by the change of polarity of voltage applied to two driving electrodes. Both of white and black particles move to the driving electrodes when each driving electrode is applied to positive and negative voltage, respectively, we can see color image through the common electrode.