Driving waveform optimization of electrowetting displays based on pixel’s 2-D model for reducing oil reflux

Abstract

Electrowetting displays (EWD) are believed to represent a new generation of electronic paper technology with fast responses, high reflectivity, and low power consumption. Despite their bright market prospects, the luminance stability of displays is still hindered by oil film reflux. So, we presented a combination of simulation and experimentation to enhance the performance of EWD. Firstly, an EWD simulation model was established using the phase field method (PFM). To ensure the accuracy of the model, it was proposed that the use of velocity field parameters could suppress mass non-conservation. During a 10-second simulation process, the total mass decreased by only 7.94x10-6%. Furthermore, the charge accumulation field was introduced to simulate oil film reflux. For the 5-second simulation, the maximum charge accumulation in the DC driving waveform was 2.61x10-5C/m2. Meanwhile, it was demonstrated that the AC driving waveform reduced charge accumulation in the three-phase contact line (TPCL) by 7.62% compared to the DC driving waveform. Based on this simulation model, a driving waveform was proposed, which included a driving waveform with a gradient changing waveform to achieve fast opening, and an alternating current (AC) driving waveform stage to inhibit the charge accumulation. The experimental results indicated that the maximum luminance fluctuation was 8.82, and the luminance data variance was 3.34 by using the proposed driving waveform. Compared to the traditional waveform, the response time was improved by 75.9%, the luminance was improved by 4.70%, and the luminance fluctuation stability improved by 79.34%.