A Multi-Stage Reset Driving Scheme Based on the Sawtooth Function for Suppressing Oil Splitting of Electrowetting Displays

Abstract

Electrowetting display (EWD) is a new reflective “paper-like” display technology based on fast response microfluidic manipulation technology. It has the advantages of low energy consumption, visual health, and flexibility. However, EWDs are often plagued by oil splitting phenomena and charge trapping effects during a driving process, seriously affecting their display performance. Therefore, a new multi-stage reset driving scheme based on a sawtooth function was proposed, which could effectively solve these defects. It consisted of a shrinking stage and a stabilizing stage. First, the proposed driving scheme was driven by a negative voltage by analyzing the voltage characteristic curve. Second, based on the splitting theory, an exponential function was applied to make the pixel's oil rupture quickly. Then, a sawtooth function was applied to enable oil to achieve secondary fusion during the cyclic driving process, effectively reducing the dispersed residual oil in pixels. Finally, a reset signal was introduced to release captured charges and suppress oil backflow. Experimental results showed that the response time was reduced by 25% compared with the exponential function driving scheme. Compared with the negative PWM pulse modulation driving scheme, the average brightness was improved by 9.5%.