Inhibiting Oil Splitting and Backflow in Electrowetting Displays by Designing a Power Function Driving Waveform

Abstract

Electrowetting display (EWD) is one of the latest and most promising reflective displays. However, some defects are easily caused in a driving process. For example, the aperture ratio of pixels can be reduced due to oil splitting, and the grayscale cannot be stabilized due to charge trapping. These defects can be effectively solved by designing driving waveforms for EWDs. So, a power function driving waveform was proposed in this paper, which consisted of an oil splitting suppression stage, a direct current (DC) driving stage and an oil stabilization stage. Firstly, the relationships among luminance values, power constants and driving time were measured. An optimal oil splitting suppression stage was obtained, which could effectively inhibit oil splitting. Then, the response time could be reduced by a DC voltage in the DC driving stage. Finally, a voltage slope was tested during the oil stabilization stage, which was used to counteract voltage created by the charge trapping. The experimental results showed that compared with a linear function waveform, the response time could be shortened by 16.1%, and the luminance value could be increased by 3.8%. The aperture ratio and oil stability of EWD can be effectively improved by these findings, thereby increasing its potential application in the display field.

Development of Cyclic Tetrasiloxane Polymer as a High-Performance Dielectric and Hydrophobic Layer for Electrowetting Displays

“…Two types of electrowetting display devices were constructed using CTP film as a basis. 46 EWD1 was produced by using a 1.2 μm CTP film as both a dielectric and hydrophobic layer, following established procedures (Figure S2). On the other hand, EWD2 was made by employing a 1.2 μm CTP film solely as a dielectric layer, with an 800 nm fluoropolymer (Hyflon AD) applied to the surface of the CTP film as a hydrophobic layer.…”

“…Two types of electrowetting display devices were constructed using CTP film as a basis . EWD1 was produced by using a 1.2 μm CTP film as both a dielectric and hydrophobic layer, following established procedures (Figure S2).…”

High-Performance Multi-Level Grayscale Conversion by Driving Waveform Optimization in Electrowetting Displays

“…Compared to traditional electrophoretic displays, EWDs based on electrowetting technology had better performance, with the advantages of a fast response speed, wide viewing angle, and excellent readability in daylight [ 2 , 3 , 4 , 5 , 6 ]. However, some shortcomings, such as oil splitting [ 7 , 8 , 9 ], oil backflow [ 10 , 11 ], charge trapping [ 12 , 13 , 14 ], and the hysteresis effect [ 15 , 16 ], have a negative impact on EWD quality. The main reason for these multiple problems was the interaction between the structure of the EWD and its driving mechanism.…”

Design of Multi-DC Overdriving Waveform of Electrowetting Displays for Gray Scale Consistency

“…EWD has numerous achievements and applications in the fields of driving waveform [ 14 , 15 ]. However, the charge trapping, contact angle hysteresis, and oil splitting affected the performance of electrowetting displays; therefore, oil backflow, screen flicker, and afterimage may occur [ 16 , 17 , 18 ]. The aperture ratio of pixels was positively correlated to applied voltages due to the Lippmann–Young equation.…”