Improving Electrophoretic Particle Motion Control in Electrophoretic Displays by Eliminating the Fringing Effect via Driving Waveform Design.

Shitao Shen,Zhibin Yan,Lingling Shui,Guofu Zhou,Zichuan Yi,Yingxin Gong,Mingliang Jin,Chang Xu

doi:10.3390/mi9040143

Abstract

Electrophoretic display is realized by controlling colored nanoparticles moving in micrometer spaces via electrophoresis. The quality of information display is therefore affected by the unsynchronized particle moving speed and the mismatched electric signal according to the crosstalk of the electric field and inhomogeneous material distribution. In this work, we analyzed the mechanism of a fringe phenomenon that affected the information display quality of electrophoretic displays (EPDs). Electrical driving waveforms (voltage signals) are designed to reduce the fringe phenomenon. By using the optimizing driving waveform, we proposed that the fringe phenomenon is quantified as gray value that can be diminished by 25.5, while keeping a response time of 200 ms.

Highlights

Electrophoretic displays have been the subject of intense research for many years because of their wide market potential [1,2]
It was confirmed that the refreshing processes and corresponding waveforms are the main reasons behind the fringe phenomenon
The mechanism of the fringe phenomenon was analyzed by simulating the diffusion and transverse fields

Summary

Introduction

Electrophoretic displays have been the subject of intense research for many years because of their wide market potential [1,2]. The shape and form of the electric signal here is called the driving waveform. The black and white particles encapsulated in the microcapsules are positively and negatively charged, respectively. The materials in the microcapsule include insulating oil, charge control agents, electrophoretic particles and density balance agents [1,10]. The parameters relative to electrophoretic phenomenon are the mass and zeta potential of the particles, the dielectric characteristics and viscosity of the insulating oil, and the electric field strength. Bi, m and q are considered as constants; the Ei generated by electric potential has a significant effect on vi which relates directly to the display process as the key influence factor for an EPD. The incident light from the environment is partially absorbed with the rest light reflected back to the top plate to the reader’s eyes

Electrical Driving Scheme for EPDs

Devices and Software

Characterization

Results and Discussion

Conclusions