A New Switching Method of Two-Dimensional EWOD-Based Droplet Translation on Single-Plate Configuration

In electrowetting-on-dielectric (EWOD), droplet can be transported using either parallel-plate configuration or single-plate configuration of electrodes. Single-plate configuration, i.e. without cover plate, is less popular due to its difficulty in successive translation of droplet and slow translation speed, in spite of its enhanced flexibility in interfacing with other components. This paper investigates the effect of switching method on droplet translation for the single-plate configuration. Droplet was transported on a two-dimensional four by four electrode array by EWOD actuation. In previous works, high voltage and ground condition were applied on two activating electrodes, maintaining other surrounding electrodes in floating state. Here, we propose a new switching method in which all the electrodes are grounded except one activating electrode. We compared the performance of the present switching method with conventional ones using the same electrode array. Performance of each method was experimentally examined with respect to maximum translation speed in which successive translation was possible. Our method showed much better performance under various experimental conditions. In addition, the present method does not necessitate the floating condition, which leads to the reduction of the number of switches and controllers to a half of conventional one.