Electric Ejection of Viscous Inks From MEMS Capillary Array Head for Direct Drawing of Fine Patterns

Free-space microink streams are realized by an array of microcapillaries. Ink is ejected from capillaries accelerated by an electric field with low or no back pressure applied. The capillaries are 20 mum in diameter, whereas the microstreams are only a few micrometers thick due to the Taylor cone effect. This method enables one to draw very fine lines down to 1 mum without lithographical techniques. With a pulsed-field application, dotted lines can also be drawn. Direct drawing of both solid and dotted lines has successfully been demonstrated by applying dc and 500-Hz ac fields, respectively.