Laminate-type piezoelectric device and method for manufacturing the same

Abstract

A laminate-type piezoelectric device includes: a piezoelectric layer ( 2 ); and an internal electrode layer ( 3 ) which is laminated on the piezoelectric layer ( 2 ), has a lower surface flat along a surface of the piezoelectric layer ( 2 ) and has an edge sidewall in its tip portion having an inclined surface ( 3 A) making an acute angle with respect to the surface of the underlying piezoelectric layer ( 2 ). The piezoelectric layers ( 2 ) and the internal electrode layers ( 3 ) are alternately laminated on each other.

1 . A method for manufacturing a laminate-type piezoelectric device, comprising: 
 a first ceramic printing step of printing and forming a ceramic layer as nonfired;    an electrode printing step of printing an electrode material paste on a surface of the ceramic layer as nonfired to form an electrode layer as nonfired on the surface of the ceramic layer as nonfired, the electrode layer as nonfired having an edge portion in which a 2° to 30° angle is made by an approximate line which is obtained by the least-squares method and is five times a length of an average thickness from a tip of an upper side of the edge portion;    a second ceramic printing step of printing and forming another ceramic layer as nonfired on the ceramic layer as nonfired having the electrode layer as nonfired formed thereon; and    a step of firing a lamination body formed by sequentially repeating the first ceramic printing step, the electrode printing step and the second ceramic printing step.    
   
   
       2 . The method for manufacturing a laminate-type piezoelectric device according to  claim 1 , wherein the ceramic layer as nonfired is made of a piezoelectric material.  
   
   
       3 . The method for manufacturing a laminate-type piezoelectric device according to  claim 1 , wherein the first and second ceramic layers as printed has surface roughness (arithmetic mean roughness: Ra) prepared to be 0.05 μm to 0.5 μm.  
   
   
       4 . The method for manufacturing a laminate-type piezoelectric device according to  claim 1 , wherein the electrode material paste forming the edge portion of the electrode layer as nonfired is set lower in viscosity than the electrode material paste forming an intermediate portion thereof.  
   
   
       5 . The method for manufacturing a laminate-type piezoelectric device according to  claim 3 , wherein the electrode material paste has a viscosity of 30 to 3000 Pa·sec.  
   
   
       6 . The method for manufacturing a laminate-type piezoelectric device according to  claim 5 , wherein 
 the electrode material paste has a ratio of a binder therein prepared at 1 wt % to 10 wt %,    the electrode material paste has a ratio of a solvent therein prepared at 5 wt % to 20 wt % and    the electrode material paste has metal particles of a mean particle diameter in prepared at 0.1 μm to 4 μm.