Method of forming piezoelectric actuator of inkjet head

Abstract

A method of forming a piezoelectric actuator of an inkjet head formed on a vibrating plate to provide a driving power for ejecting ink to each of pressure chambers is provided. The method includes forming a lower electrode on a vibrating plate, forming a piezoelectric layer on the lower electrode to be located above each of pressure chambers, forming a protecting layer covering the lower electrode and the piezoelectric layer, exposing an upper surface of the piezoelectric layer by decreasing a thickness of the protecting layer and the piezoelectric layer, forming an upper electrode on the upper surface of the piezoelectric layer, removing the protecting layer. According to the present invention, since the piezoelectric layer having a flat upper surface is formed in uniform figure, area and thickness of the upper electrode formed thereon is uniformly controlled.

1 . An inkjet head comprising:
 a plate having a nozzle;   a flow channel plate disposed on the plate;   a vibrating plate disposed on the flow channel plate; a lower electrode disposed on the vibrating plate;   a piezoelectric layer disposed on the lower electrode and having a flat upper surface; and   an upper electrode disposed on the piezoelectric layer.   
     
     
         2 . The inkjet head of  claim 1 , further comprising an insulating layer disposed between the vibrating plate and the lower electrode. 
     
     
         3 . The inkjet head of  claim 2 , wherein the insulating layer has a silicon oxide or silicon nitride material. 
     
     
         4 . The inkjet head of  claim 2 , wherein the piezoelectric layer has a rounded side surface. 
     
     
         5 . The inkjet head of  claim 4 , wherein the insulating layer has a silicon oxide or silicon nitride material. 
     
     
         6 . The inkjet head of  claim 4 , wherein the piezoelectric layer has a thickness of about 10 μm to about 30 μm. 
     
     
         7 . The inkjet head of  claim 6 , wherein the insulating layer has a silicon oxide or silicon nitride material. 
     
     
         8 . The inkjet head of  claim 6 , wherein the piezoelectric layer has a lead ziroconate titanate ceramic material. 
     
     
         9 . The inkjet head of  claim 8 , wherein the insulating layer has a silicon oxide or silicon nitride material. 
     
     
         10 . The inkjet head of  claim 4 , wherein the piezoelectric layer has a lead ziroconate titanate ceramic material. 
     
     
         11 . The inkjet head of  claim 2 , wherein the piezoelectric layer has a thickness of about 10 μm to about 30 μm. 
     
     
         12 . The inkjet head of  claim 10 , wherein the piezoelectric layer has a lead ziroconate titanate ceramic material. 
     
     
         13 . The inkjet head of  claim 2 , wherein the piezoelectric layer has a lead ziroconate titanate ceramic material. 
     
     
         14 . The inkjet head of  claim 1 , wherein the piezoelectric layer has a rounded side surface. 
     
     
         15 . The inkjet head of  claim 14 , wherein the piezoelectric layer has a thickness of about 10 μm to about 30 μm. 
     
     
         16 . The inkjet head of  claim 15 , wherein the piezoelectric layer has a lead ziroconate titanate ceramic material. 
     
     
         17 . The inkjet head of  claim 14 , wherein the piezoelectric layer has a lead ziroconate titanate ceramic material. 
     
     
         18 . The inkjet head of  claim 1 , wherein the piezoelectric layer has a thickness of about 10 μm to about 30 μm. 
     
     
         19 . The inkjet head of  claim 18 , wherein the piezoelectric layer has a lead ziroconate titanate ceramic material. 
     
     
         20 . The inkjet head of  claim 1 , wherein the piezoelectric layer has a lead ziroconate titanate ceramic material.