Fluid ejection nozzle having stacked capacitive ejector

Abstract

A fluid ejection nozzle arrangement is provided having drive circuitry deposited on a substrate, subsequent etchant layers deposited on the drive circuitry to define a nozzle chamber with walls and a roof structure defining a fluid ejection port, and a stacked capacitive actuator arranged in the chamber. The actuator has alternate electrode plates sandwiched between a compressible polymer. Activation of the stacked actuator draws the electrode plates together to compress the polymer storing energy therein, with subsequent de-activation releasing the energy to eject fluid within the chamber from the ejection port.

1 . A fluid ejection nozzle arrangement comprising:
 drive circuitry deposited on a substrate;   subsequent etchant layers deposited on the drive circuitry to define a nozzle chamber with walls and a roof structure defining a fluid ejection port; and   a stacked capacitive actuator arranged in said chamber, said actuator having electrode plates sandwiched alternately between a compressible polymer, wherein activation of the stacked actuator draws the electrode plates together to compress the polymer storing energy therein, with subsequent de-activation releasing said energy to eject fluid within said chamber from the ejection port.   
     
     
         2 . An arrangement according to  claim 1 , wherein the electrode actuator is constructed according to chemical vapor deposition (CVD) techniques. 
     
     
         3 . An arrangement according to  claim 1 , wherein the electrode plates comprise separate metals. 
     
     
         4 . An arrangement according to  claim 3 , wherein the electrodes are comprised of alternating aluminium and tantalum plates. 
     
     
         5 . An arrangement according to  claim 4 , wherein the alternating metal plates define electrodes on opposite sides of the actuator, said corresponding electrodes electrically isolated from each other and connected to the drive circuitry. 
     
     
         6 . An arrangement according to  claim 1 , wherein the layer of drive circuitry is a two-level metal CMOS layer. 
     
     
         7 . An arrangement according to  claim 1 , wherein the polymer comprises styrene-ethylene-butylene-styrene block copolymer.