Toward Suppressing Charge Trapping Based on a Combined Driving Waveform with an AC Reset Signal for Electro-Fluidic Displays

Abstract

Digital microfluidic technology based on the principle of electrowetting is developing rapidly. As an extension of this technology, electro-fluidic displays (EFDs) have gradually become a novel type of display devices, whose grayscales can be displayed by controlling oil film in pixels with a microelectromechanical system (MEMS). Nevertheless, charge trapping can occur during EFDs’ driving process, which will produce the leakage current and seriously affect the performance of EFDs. Thus, an efficient driving waveform was proposed to resolve these defects in EFDs. It consisted of a driving stage and a stabilizing stage. Firstly, the response time of oil film was shortened by applying an overdriving voltage in the driving stage according to the principle of the electrowetting. Then, a direct current (DC) voltage was designed to display a target luminance by analyzing leakage current-voltage curves and a dielectric loss factor. Finally, an alternating current (AC) reset signal was applied in the stabilizing stage to suppress the charge trapping effect. The experiment results indicated that compared with a driving waveform with a reset signal and a combined driving waveform, the average luminance was improved by 3.4% and 9.7%, and the response time was reduced by 29.63% and 51.54%, respectively.