Display Applications of Electrowetting

Abstract

A reflective display device based on electrowetting technology exhibits high reflection index over 40% and contrast ratio over 15 (conventional paper has reflection index of 60% and contrast index of 15). In addition to the attractive optical properties, this technology manifests a fast video response rate (<10 ms) and colour conversion factor of 67% which is four times higher than standard electrophoretic displays. These factors show that electrowetting technology is a strong alternative to electrophoretic technique which enables reflective displays available to the e-reader market. This technology offers advantages of insensitivity to cellgap variations and thus can be used to create electronic paper with excellent video capability at low cost. In this review we present the working principle, fabrication procedure and electro-optic response study of electrowetting display. Different challenges still to be overcome also have been discussed in detail.

Oil Conductivity, Electric-Field-Induced Interfacial Charge Effects, and Their Influence on the Electro-Optical Response of Electrowetting Display Devices

“…During the transition stage, the increase in OR min indicates that the closing speed of the device becomes slower in time. It has been mentioned in the literature that charge trapping can cause the slow closing phenomenon of the EWD device, similar to how charge trapping leads to the rebound effect [9,11,30,32,33]. The transition regime therefore implies an asymmetric degree of charge trapping and detrapping, causing a continuous increase of the number of the trapped charges in the dielectric, while the device is being driven periodically.…”

“…From the perspective of the electromechanical explanation of electrowetting, both effects reduce the charge accumulation at the liquid/dielectric interface [5][6][7][8], thereby reducing the electrowetting force that keeps the TCL in place. Hence, the backflow phenomenon can result from the charge trapping or leakage processes in the EWD device [9][10][11]. The charge trapping effect has been reported to be related to the charge species, that is, dependent on the driving voltage polarity [12].…”

A Combined Pulse Driving Waveform With Rising Gradient for Improving the Aperture Ratio of Electrowetting Displays

“…The phenomenon of charge trapping exists in EWDs. The charge trapping on the dielectric layer of EWDs can influence the stability of display effect, resulting in slow response speed and few gray scales [2]. Figure 4 illustrates the charge trapping phenomenon in an EWD.…”

“…Electrowetting displays (EWDs) are a kind of reflective display technology with the ability of videospeed display applications; its fluidic pixels can respond and switch quickly by controlling electronic [1]. And it shows excellent electro-optic characteristics like low operating voltage, thinness, fast response, wide viewing angle, and low power consumption [2,3]. EWD makes up the performance bottlenecks in full-color display and real-time dynamic video display [4][5][6][7][8]; it is known to be one of the most attractive emerging display technologies [15].…”

Accurate, consistent, and fast droplet splitting and dispensing in electrowetting on dielectric digital microfluidics

“…In addition, direct manipulation of discrete droplets enables fabrication and operation of highly automated microfluidics systems with more flexibility and higher efficiency [6][7][8][9][10][11][12]. Due to these unique advantages, EWOD digital microfluidics has been used for tremendous applications such as medical [13][14][15][16][17][18][19], display [20,21], optics [22,23], and cooling [24,25]. In addition, there are many recent EWOD studies on engineering applications such as optofluidics and solar energy [26,27].…”