A hybrid electrohydrodynamic drop-on-demand printing system using a piezoelectric MEMS nozzle

A unique hybrid jetting system based on electrohydrodynamic and piezoelectric forces has been designed to verify the control of the drop velocity and to obtain ultrafine droplets with a high jetting frequency. Piezoelectric nozzles have been fabricated using silicon on insulator wafers and Pyrex glass employing a MEMS process and an anodic bonding process. The plate-type electrode and moving stage were used for the printing process. The droplet ejection mechanisms from the nozzle using the hybrid jetting system were captured by a high-speed camera synchronized with a trigger signal. The deformation of the meniscus and the jetting delay time in regard to the high operational firing frequency were investigated. It was found that controlling the droplet velocity without a change in the droplet volume and obtaining a smaller dot (59 mu m in diameter) in hybrid printing mode compared with inkjet printing mode (151 mu m in diameter) were possible. These results show this system's promising applicability to the fabrication of micro patterning for a wide range of printed electronics applications.