Fundamental Mechanisms of Electrophoretic Displays

This chapter reviews the operational principles and fundamental mechanisms of the electrophoretic electronic ink display, including the Electrophoretic Displays (EPD) driving scheme, materials design, Charged Inverse Micelles (CIMs) dynamics, charged particle behaviors, and color EPD. Electronic ink contains pigment particles, charge controlling agents (CCAs), non-polar solvents, and various additives. When a potential difference is applied between two electrodes, the CIMs will move under the influence of the electric field toward the electrode with the opposite polarity. Due to the motion of the CIMs, their distribution in the liquid changes influence the distribution of the electric field. It has been observed that CIMs can transfer from the diffuse double layer to form a charged Stern layer of CIMs attached to the surface. When the CCAs are added into an electrophoretic dispersion containing pigment particles, the hydrophilic side of the surfactant molecules rapidly coats the particles, with the hydrophobic tail turned toward the non-polar solvent. © 2022 John Wiley & Sons Ltd. All rights reserved.