In recent years, the open electrowetting on dielectric (EWOD) device has been widely used in biomedical detection, chemical synthesis analysis, and so on. However, the cost of using ITO glass as surface material is difficult to meet the requirement for large-scale array chip production. So, a low-cost, easy-to-manufacture open EWOD platform is designed in this paper. In hardware platform, an operation platform is prepared by using a printed circuit board (PCB) as a substrate. The electrode shape is designed as zigzag, and its surface is optimized by organic solderability preservatives (OSP). In addition, Parafilm M and silicone oil are used as a dielectric hydrophobic layer to prepare the open platform. In software, the system program is designed by C programming language, including initialization program, serial port communication program, high-voltage output port program, and interrupt program, which can be used to drive droplets. The system can achieve an effective driving voltage of 180-240 V. The moving speed of droplets can reach 15 mm/s when the droplet volume is 1850 µL and the electrode voltage output frequency is 10 Hz.

A fast response speed of a pixel is important for electrowetting displays (EWDs). However, traditional driving waveforms of EWDs have the disadvantage of long response time. So, a driving waveform, which based on overdriving voltages and charge trapping theory, was proposed in this paper to shorten the response time of EWDs. The driving waveform was composed of an overdriving stage and a driving stage. Firstly, a simplified physical model was introduced to analyze the influence of driving voltages on the response time. Then, an overdriving voltage was applied in the overdriving stage to increase the respond speed of oil, and a target voltage was applied in the driving stage to obtain a target luminance. In addition, the effect of different overdriving voltages and overdriving time values on the response time was analyzed by charge trapping theory to achieve an optimal performance. Finally, the driving waveform was imported into an EWD for performance testing. Experimental results showed that the response time of the EWD can be shortened by 29.27% compared with a PWM driving waveform.

At present, three-color electrophoretic displays (EPDs) have problems of dim brightness and insufficient color saturation. In this paper, a driving waveform based on a damping oscillation was proposed to optimize the red saturation in three-color EPDs. The optimized driving waveform was composed of an erasing stage, a particles activation stage, a red electrophoretic particles purification stage, and a red display stage. The driving duration was set to 360 ms, 880 ms, 400 ms, and 2400 ms, respectively. The erasing stage was used to erase the current pixel state and refresh to a black state. The particles’ activation stage was set as two cycles, and then refreshed to the black state. The red electrophoretic particles’ purification stage was a damping oscillation driving waveform. The red and black electrophoretic particles were separated by changing the magnitude and polarity of applied electric filed, so that the red electrophoretic particles were purified. The red display stage was a low positive voltage, and red electrophoretic particles were driven to the common electrode to display a red state. The experimental results showed that the maximum red saturation could reach 0.583, which was increased by 27.57% compared with the traditional driving waveform.