Method of forming thick layer by screen printing and method of forming piezoelectric actuator of inkjet head

Abstract

A method to form a thick layer by screen printing and a method to form a piezoelectric actuator of an inkjet head. The method to form the thick layer including forming a guide groove in a surface to a predetermined depth, and forming the thick layer by applying a material to the surface inside the guide groove through screen printing. The method to form the piezoelectric actuator including forming an insulating layer on a top surface of a vibration plate and forming a guide groove in the top surface of the vibration plate or an insulating layer to a predetermined depth at a position corresponding to each of a plurality of pressure chambers, forming a lower electrode on the top surface of the insulating layer; forming a piezoelectric layer inside the guide groove by screen printing, and forming an upper electrode on a top surface of the piezoelectric layer.

1 . A method of forming a piezoelectric actuator on a vibration plate of an inkjet head, the method comprising:
 forming an insulating layer on a top surface of the vibration plate;   forming a guide groove at a top surface of the vibration plate or the insulating layer to a predetermined depth at a position corresponding to a pressure chamber of the inkjet head;   forming a lower electrode on the top surface of the insulating layer;   applying a piezoelectric material to a top surface of the lower electrode inside the guide groove by screen printing to form a piezoelectric layer; and   forming an upper electrode on a top surface of the piezoelectric layer.   
     
     
         2 . The method of  claim 1 , wherein the piezoelectric material comprises a paste. 
     
     
         3 . The method of  claim 1 , wherein the guide groove is formed at the top surface of the vibration plate, and then the insulating layer is formed on the top surface of the vibration plate. 
     
     
         4 . The method of  claim 1 , wherein the insulating layer is formed on the top surface of the vibration plate, and then the guide groove is formed at the top surface of the insulating layer. 
     
     
         5 . The method of  claim 1 , wherein the insulating layer is a silicon oxide layer. 
     
     
         6 . The method of  claim 1 , wherein the forming of the lower electrode comprises depositing a conductive metal on the top surface of the insulating layer to a predetermined thickness. 
     
     
         7 . The method of  claim 6 , wherein the forming of the lower electrode comprises sequentially depositing a Ti layer and a Pt layer through sputtering. 
     
     
         8 . The method of  claim 1 , wherein the guide groove has the same contour as a desired contour of the piezoelectric layer. 
     
     
         9 . The method of  claim 1 , wherein the forming of the guide groove comprises forming a guide groove having a same contour as a desired contour of the piezoelectric layer after the lower electrode is formed at the top surface of the insulating layer. 
     
     
         10 . The method of  claim 8 , wherein the guide groove has a width corresponding to the width of the pressure chamber. 
     
     
         11 . The method of  claim 1 , wherein the applying of the piezoelectric material comprises applying a piezoelectric material paste inside the guide groove in such a manner that the width of the piezoelectric material paste applied is smaller than the width of the guide. 
     
     
         12 . The method of  claim 11 , wherein the applying of the piezoelectric material paste further comprises:
 allowing the piezoelectric material paste applied inside the guide groove to spread laterally to have a width corresponding to the width of the guide groove.   
     
     
         13 . The method of  claim 11 , wherein the applying of the piezoelectric material paste further comprises:
 allowing the piezoelectric material paste applied inside the guide groove to spread laterally to have a uniform thickness, a uniform width, and a straightened vertical outer edge.   
     
     
         14 . The method of  claim 1 , wherein the forming of the upper electrode comprises applying an electrode material paste to the top surface of the piezoelectric layer by screen printing. 
     
     
         15 . The method of  claim 14 , further comprising:
 sintering the piezoelectric layer and the upper electrode.   
     
     
         16 . The method of  claim 1 , wherein the forming of the upper electrode comprises depositing a conductive metal on the top surface of the piezoelectric layer to a predetermined thickness by sputtering. 
     
     
         17 . The method of  claim 16 , further comprising:
 sintering the piezoelectric layer prior to the forming of the upper electrode.   
     
     
         18 . A method of forming a piezoelectric actuator, the method comprising:
 forming guide grooves at a first surface of a vibration plate;   forming a lower electrode along the first surface of the vibration plate, including the guide grooves;   applying a piezoelectric material to the lower electrode at the guide grooves; and   forming an upper electrode over the piezoelectric material.   
     
     
         19 . The method of  claim 18 , wherein the piezoelectric material is a paste. 
     
     
         20 . The method of  claim 18 , wherein the applying of the piezoelectric material includes spreading the piezoelectric material along an entire surface of the guide groove. 
     
     
         21 . The method of  claim 20 , wherein the applying of the piezoelectric material comprises screen printing the piezoelectric material to form a piezoelectric layer. 
     
     
         22 . The method of  claim 18 , further comprising:
 forming an insulating layer over the first surface of the vibration plate before forming the lower electrode along the first surface of the vibration plate.   
     
     
         23 . The method of  claim 22 , wherein:
 the forming of the guide grooves at a first surface of the vibration plate comprises forming of guide grooves at a surface of the insulating layer; and   the forming of the lower electrode along the first surface of the vibration plate, including the guide grooves comprises forming a lower electrode along a top surface of the insulating layer, including the guide grooves.