Kuo-Lung Lo

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.

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.

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.