Development of a Femtoliter Piezo Ink-jet Head for high resolu- tion printing

摘要

Inkjet printing technology is used in the manufacture of color filters and alignment layer film for liquid crystal displays. The minimum droplet volume is achieved under a few picoliters and the head prints lines of a few tens of micrometers. In order to expand range of applications of the inkjet technology, we consider that a inkjet head is needed with the ability to micropattern feature sizes of 10 micrometers. The size of features depends mainly on the volume of ink contained in droplets fired from an inkjet head. This work presents a new inkjet head comprising piezoelectric actuators that fires droplets having a volume of less than 1 picoliter. Examples in which the inkjet head was used to directly deposit ink droplets to micropattern devices are described. An efficient approach has been taken to develop the inkjet head so that the head structures are optimized and micro-droplet behavior is controlled. The inkjet head is found to be capable of firing 500-femtoliter droplets and forming micropatterns on a substrate. The droplets exhibit a stable, straight flight path.