Micro-electromechanical fluid ejection device that incorporates a shape memory alloy based actuator

摘要

A micro-electromechanical fluid ejection device includes a wafer substrate. Drive circuitry is positioned on the wafer substrate. A nozzle chamber structure is arranged on the wafer substrate to define a nozzle chamber and a fluid ejection port in fluid communication with the nozzle chamber. A fluid ejection member is operatively positioned with respect to the nozzle chamber such that displacement of the fluid ejection member results in the ejection of fluid from the fluid ejection port. At least a portion of the fluid ejection member is of a shape memory alloy which defines an electrical heating circuit and which is connected to the drive circuitry to be heated by an electrical current received from the drive circuitry, the shape memory alloy being displaceable towards the fluid ejection port when heated to transform from its martensitic phase to its austenitic phase to eject fluid from the fluid ejection port.