Liu Linwei, Bai Pengfei, Yi Zichuan, Zhou Guofu
Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China.
College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China.
Micromachines (Basel). 2021 Apr 27;12(5):491. doi: 10.3390/mi12050491.
The electrowetting display (EWD) is a kind of reflective paper-like display. Flicker and grayscale distortion are caused by oil backflow, which is one of the important factors restricting the wide application of EWDs. The charge embedding caused by the electric field force in the dielectric layer is the cause of oil backflow. To suppress oil backflow, a separated reset waveform based on the study of oil movement is proposed in this paper. The driving waveform is divided into two parts: a reset waveform and a grayscale waveform. The reset waveform generated by a reset circuit can be used to output various voltages. The grayscale waveform is set as a traditional PWM waveform. The reset waveform is composed of a charge-releasing stage and oil-moving back stage. Two phases are contained in the charge releasing stage. The overdriving voltage is used during the first phase to reverse the voltage of all pixels. The trapped charges can then be released from the dielectric layer during the second phase. A higher voltage is used during the oil-moving back stage to drive the oil faster in the pixel. By comparing the experimental data, the oil backflow time is extended 761 times by the reset waveform. The four grayscales can be maintained by the reset waveform after driving for 300 s.
电润湿显示器（EWD）是一种类似反射纸的显示器。油回流会导致闪烁和灰度失真，这是限制EWD广泛应用的重要因素之一。介质层中电场力引起的电荷嵌入是油回流的原因。为了抑制油回流，本文基于对油运动的研究提出了一种分离的复位波形。驱动波形分为两部分：复位波形和灰度波形。复位电路产生的复位波形可用于输出各种电压。灰度波形设置为传统的脉宽调制（PWM）波形。复位波形由电荷释放阶段和油回流阶段组成。电荷释放阶段包含两个阶段。在第一阶段使用过驱动电压来反转所有像素的电压。然后在第二阶段，捕获的电荷可以从介质层中释放出来。在油回流阶段使用更高的电压来使像素中的油更快地移动。通过比较实验数据，复位波形将油回流时间延长了761倍。驱动300秒后，复位波形可以维持四个灰度级。
