Test Structure for Characterizing Low Voltage Coplanar EWOD System

This paper presents test structures designed for studying the relationship between the operating voltage and different electrode configurations and areas for coplanar electrowetting on dielectrics (EWOD) devices. New test structures have been designed and fabricated using anodic Ta₂O₅ dielectric and thin aFP (amorphous Fluoropolymer CYTOP from Asahi Glass Co., Ltd.). These test structures have been used to characterize the contact angle change, which is between 114deg and 81deg with an applied voltage of less than 20 V. This demonstrates that by modifying the coplanar architecture, the operating voltage can be reduced by a factor of two, compared to previously reported coplanar EWOD structures. Droplet manipulation on a coplanar EWOD system with this new design has been successfully demonstrated, with a driving voltage of 15 V.