Wei-Yuan Cheng

Single-layered multi-color electrowetting display by using ink-jet-printing technology and fluid-motion prediction with simulation

— This paper describes a single-layered multi-color electrowetting display (EWD) by using ink-jet-printing (IJP) technology and comparing different pattern electrodes with the use of the numerical investigations of ANSYS FLUENT®. This work consists of two parts: the first describes the design of implementing a single-layered multi-color EWD and the second demonstrates the application of ANSYS FLUENT® simulation in different pattern electrodes settings on the proposed EWD. The single-layered multi-color EW device was evaluated by using various colored oils without adopting a color filter. The single-layered multi-color EWD at a driving voltage of 25 V can achieve a maximum aperture ratio and reflectivity of 80% and 38.5%, respectively. The colored saturation of R, G, B oils can increase to 50% (NTSC: 13.3–27.8%). In addition, a radiate electrode at the required viewable area condition of 85% and force 5 * Fk, which results in ink stable contraction and a shorter response time of 50% (radiate vs. square), was proposed. The experimental results and simulation demonstrate that ink-jet-printing (IJP) technology along with the use of radiate electrodes can result in a single-layered multi-color EWD with a shorter response time.

3D electrohydrodynamic simulation of electrowetting displays

The fluid dynamic behavior within a pixel of an electrowetting display (EWD) is thoroughly investigated through a 3D simulation. By coupling the electrohydrodynamic (EHD) force deduced from the Maxwell stress tensor with the laminar phase field of the oil–water dual phase, the complete switch processes of an EWD, including the break-up and the electrowetting stages in the switch-on process (with voltage) and the oil spreading in the switch-off process (without voltage), are successfully simulated. By considering the factor of the change in the apparent contact angle at the contact line, the electro–optic performance obtained from the simulation is found to agree well with its corresponding experiment. The proposed model is used to parametrically predict the effect of interfacial (e.g. contact angle of grid) and geometric (e.g. oil thickness and pixel size) properties on the defects of an EWD, such as oil dewetting patterns, oil overflow, and oil non-recovery. With the help of the defect analysis, a highly stable EWD is both experimentally realized and numerically analyzed.

19‐1: A Novel Electrowetting‐based Display for Future Smart Window Application

Smart window is an emerging application for display industry. It can control the sunlight penetration and display information. In this paper, we had made 6-inch color smart window prototype by electrowetting-based technique. The ink jet process is adopted to dose various colored oil into sub-pixel to achieve color device. Without color filter, the transmittance of the device can be improved. Further, to evaluate the practicability of using the smart window device in the night, we had added luminescence substances into the colored oils and designed the cladding structure to achieve a luminous smart window.

34.3: Novel Development of Multi-Color Electrowetting Display

A panel manufacturing process for multi-color electrowetting display (EWD) by using ink-jet printing (IJP) technique had been developed. To achieve multi-color, two strategies were used, i.e., by using black oil with color filter and by using various colored oils without adopting color filter. for colored oils, various dyes had been used to blend with alkane solution. Then, the jetting behavior of different colored oil for IJP was investigated. Here, a 6-inch multi-color EWD prototype with black oil and color filter was successfully fabricated, and a dual color EWD panel with black and red oils had also been first evaluated.

7.4: A Stacking Color Electrowetting Display for the Smart Window Application

The electrowetting display with the property of transflective is applicable as windows. However, low transmittance is a key issue of a stacking color electrowetting display as a window application. To improve the transmittance, an advanced oil splitting suppression waveform was proposed. Finally, a stacking color electrowetting display for the smart window application has been demonstrated. And the transmittance up to 30% has been attended.

27.3: A Decoupling Driving Scheme for Low Voltage Stress in Driving a Large-Area High-Resolution Electrowetting Display

To reduce voltage stress on TFT backplane of electrowetting displays, this paper develops a decoupling driving scheme to diminish the induced voltage stress and allow AC common to reduce the required output voltage from driver IC. Satisfactory results can be obtained on a largest area and highest resolution electrowetting display.

63.2: Single Layer Multi‐Color Electrowetting Display by Using Ink Jet Printing Technology and Fluid Motion Prediction with Simulation

For outdoor multimedia device, electrowetting display (EWD) is one of the potential technologies. In this paper, we evaluated the single layer multi-color EW device by using various colored oils without adopting color filter. The oils were dosed into the pixel by using ink-jet printing (UP) technique. for colored oils, in order to improve the color saturation of EWD panel, we used mixed solvent to increase the solubility of dyes. Then, by using UP technique, a single layer multi-color EW device was successfully fabricated and the optical property had been evaluated. Also, to improve the reliability of fluid motion, a simulation named FLUENT was first adopted to predict and realize the fluid behavior under different electric force.

P-142: Multi-Domain Alignment Technology by Ink-Jet Printing

This study developed an ink-jet printing method capable of producing multi-domain alignment liquid crystal displays. Based on the drop-on-demand characteristics of ink jet printing, the inks location in different alignment manners could be defined in one pixel. This paper describes two practical applications. The first involves integrating the hybrid aligned zone with the homeotropic aligned area in one pixel to create a multi-domain alignment when the voltage is applied. This proposed method achieved a wide viewing angle. The second, similar approach using ink jet printing was performed on a single-cell-gap transflective liquid crystal display. A 2.4-in 170-ppi prototype demonstrates mass-production feasibility.