Electrohydrodynamics (EHD) jet printing technology has been chosen as the main alternatives for overcoming the limitation of the conventional lithography fabrication process. This printing technology provides relatively low-cost, simple fabrication process of the micro-devices. Compared with the conventional inkjet printing, the EHD jet printing is able to realize below 20 μm patterning even though with high viscosity ink.
The main objective of this thesis is performing the basic study of the tiny patterning below 20 μm by using EHD jet printing focused on the dot printing realized by drop-on-demand (DoD) ejection mode. In this study, both ink type conductive and non-conductive ink were used. Silver (Ag) nano-particles ink and UV-curable photopolymer ink was used as the conductive and non conductive ink respectively. In the real application, the dot patterned with photopolymer material is mostly used for the micro-lens and micro-lens arrays fabrication. Therefore this thesis also presents the study of the micro-lens and micro-lens arrays fabrication on the flexible substrate as the implementation of dot printing real application. Finally this thesis presents the analysis of the dot uniformity and the effect of some physical parameters including the temperature and the surface wettability of the printing substrate on the dot morphologies.
This study shows that the uniform Ag dots below 10 μm could be realized by using EHD jet printing. The dot diameter increased up to 14 μm while the substrate was heat up to 40 0C. Furthermore this study shows that the EHD jet printing technology could be used as the breakthrough for the low-cost and rapid fabrication of tiny micro-lens and micro-lens array on the flexible substrate. The optical parameters of the micro-lens could be adjusted as controlling the printing drop number during printing process. The minimum and maximum micro-lens diameter could be fabricated was 11.92 μm and 24.4 μm respectively.