  Herein, we describe a novel device configuration for double-plate
electrowetting-on-dielectric system with a floating top-electrode. As
conventional double-plate EWOD device requires a grounded electrode on
top-plate, it will cause additional fabrication complicity and cost during the
encapsulation process. In this work, we found that by carefully designing
electrode arrangement and configuring driving electronic circuit, the droplet
driving force can be maintained with a floating electrode on the top-plate.
This can provide the possibilities to integrate additional electrical or
electrochemical sensing functions on the top-plate. We use both finite element
analysis and fabricated system to validate the theory, and the results indicate
that floating top-electrode EWOD systems are highly reliable and reproducible
once the design considerations are fully met.
