US Patent 7407273 Piezo-driven micro-droplet jet generator

A piezo-driven micro-droplet jet generator comprises an ejection seat, having an ejection plate with a plurality of ejection holes; a membrane, having a front side facing the ejection seat and a rear side; a piezoelectric plate, placed at the rear side of the membrane, at least partly touching the membrane and, when electric voltage is applied, driving a vibrating movement of the membrane towards the ejection plate; a base plate, at four corners thereof fastened to the ejection seat and to the membrane; and a flow path inside the ejection seat, allowing liquid to be let into a space inside the ejection seat; wherein liquid between the membrane and the ejection plate upon the vibrating movement undergoes pressure, being ejected through the plurality of ejection holes.