Photolithography Fabricated Spacer Arrays Offering Mechanical Strengthening and Oil Motion Control in Electrowetting Displays Introducing spacers into pixelated electrowetting displays (EWDs) normally gives mechanical strengthening, while bringing undesired disturbance of wateroil interfacial dynamics. Hence, spacer array is a key pixel structure needs careful consideration in the design and fabrication of electrowetting displays. Here, we propose a spacer array, which is designed standing on the junction of adjacent pixel walls, fabricated by photolithography. The spacer array provides mechanical strength enhancement and reliable oil motion controllability. By optimizing the spacer distribution density, the EWD device may achieve 28% increase in open ratio (white area fraction) and withstand 60 Nmm2 pressure. This design of spacer array reasonably solves the contradiction between mechanical strength enhancement and optoelectronic performance in EWDs, providing potential applications in oilxe2x80x93water twophase microfluidic devices.

A New OEW Microfluidic Device based on pn Junction Compared with the electrowetting on dielectric (EWOD) microfluidic device, optoelectrowetting (OEW) microfluidic device does not need to control the onoff of single electrode, but only needs to change the lighting condition to control the droplet, simplifying the peripheral control device and improving the stability of the device. The contradiction between the operating voltage and the driving force exists in the existing OEW device. To solve this problem, this paper proposes an OEW device based on diode structure, which uses the photoelectric effect of the diode connected in the DC circuit to control the movement state of the droplet. In this paper, the feasibility of the OEW device with pn structure is theoretically analyzed. Compared with the previous OEW device, under the same applied voltage and the same illumination difference, the potential difference between the diodes in the new device will be significantly larger than the potential difference between the photoresistors, which will effectively improve the driving force of the DC drive.