Piezoelectric Actuator, Ink-Jet Head, Method Of Producing Piezoelectric Actuator, And Method Of Producing Ink-Jet Head

Abstract

A method for a piezoelectric actuator and an ink-jet head uses, for forming a lower electrode on a vibration plate, metal-nano particles which can start to sinter with a low temperature as a conductive material; and uses, for forming a piezoelectric layer, an aerosol deposition method requiring no calcination step. Accordingly, upon forming the lower electrode and piezoelectric layer, any calcination under severe condition is not needed. In addition, the calcination of the lower electrode can be advanced simultaneously with an annealing step required after forming the piezoelectric layer. Accordingly, the thermal cycle during producing process can be minimized, thereby suppressing the exfoliation of layers and diffusion of material forming vibration plate into the piezoelectric layer due to thermal history, and consequently lower the degradation of piezoelectric characteristics.

1 . A method of producing a piezoelectric actuator, comprising: 
 a first electrode layer forming step of forming, on a substrate, a first electrode layer with a conductive material which starts to sinter at a predetermined temperature;    a piezoelectric layer forming step of forming, on the first electrode layer, a piezoelectric layer by blowing aerosol containing particles of a piezoelectric material onto the first electrode layer to deposit the particles of the piezoelectric material on the first electrode layer;    an annealing treatment step of subjecting the piezoelectric layer to an annealing treatment; and    a second electrode layer forming step of forming, on the piezoelectric layer, a second electrode layer which pairs with the first electrode layer;    wherein a sintering-start temperature of the conductive material is not more than an annealing temperature in the annealing treatment step.    
   
   
       2 . The method according to  claim 1 , further comprising, before the annealing treatment step, a pre-calcination step of subjecting the first electrode layer to a pre-calcination at a temperature of not more than 420° C.  
   
   
       3 . The method according to  claim 1 , wherein the conductive material contains metal-nano particles having a particle size of not more than 50 nm.  
   
   
       4 . The method according to  claim 3 , wherein a metal of the metal-nano particles is silver.  
   
   
       5 . The method according to  claim 1 , wherein the annealing temperature is 600° C. to 1,000° C.  
   
   
       6 . The method according to  claim 1 , wherein the sintering-start temperature is not more than about 420° C.  
   
   
       7 . A method of producing an ink-jet head, comprising the steps of: 
 forming an ink channel forming body provided with a plurality of pressure chambers each of which communicates with an ink discharge nozzle for discharging an ink and each of which has an opening, the opening being open on a side of one surface of the ink channel forming body;    providing a substrate on the side of the one surface of the ink channel forming body so that the substrate closes the opening of each of the pressure chambers; and    forming a piezoelectric actuator on the substrate in accordance with the method as defined in  claim 1 .    
   
   
       8 . The method according to  claim 7 , wherein the substrate is a vibration plate.  
   
   
       9 . A piezoelectric actuator comprising: 
 a first electrode layer which is formed on a substrate and which includes metal-nano particles having a particle size of not more than 50 nm;    a piezoelectric layer provided on the first electrode layer by blowing aerosol containing particles of a piezoelectric material onto the first electrode layer to deposit the particles on the first electrode layer; and    a second electrode layer which is arranged on the piezoelectric layer and which pairs with the first electrode layer.    
   
   
       10 . The piezoelectric actuator according to  claim 9 , wherein a metal of the metal-nano particles is silver.  
   
   
       11 . The piezoelectric actuator according to  claim 9 , wherein a thickness of the first electrode layer is 100 to 300 nm.  
   
   
       12 . An ink-jet head comprising: 
 an ink channel forming body provided with a plurality of pressure chambers each of which communicates with an ink discharge nozzle for discharging an ink and each of which has an opening, the opening being open on a side of one surface of the ink channel forming body; and    the piezoelectric actuator as defined in  claim 8  in which the substrate is arranged on the side of the one surface of the ink channel forming body so that the substrate closes the opening of each of the pressure chambers.