Piezoelectric element and method of manufacturing the same

Abstract

An array of piezoelectric elements is easily manufactured by making insulating portions at side surfaces smaller. The piezoelectric element includes: a multilayered structure in which piezoelectric material layers and internal electrode layers are alternately stacked; first insulating films formed by using an AD method, for covering a first group of internal electrode layers at a first surface of the multilayered structure; second insulating films formed by using the AD method, for covering a second group of internal electrode layers at a second surface of the multilayered structure; a first external electrode connected to the second group of internal electrode layers and insulated from the first group of internal electrode layers at the first surface; and a second external electrode connected to the first group of internal electrode layers and insulated from the second group of internal electrode layers at the second surface.

1 . A piezoelectric element comprising: 
 a multilayered structure in which a plurality of piezoelectric material layers and a plurality of internal electrode layers are alternately stacked, said plurality of internal electrode layers including a first group of internal electrode layers and a second group of internal electrode layers;    first insulating films formed by using an aerosol deposition method, for covering said first group of internal electrode layers at a first surface of said multilayered structure;    second insulating films formed by using the aerosol deposition method, for covering said second group of internal electrode layers at a second surface of said multilayered structure;    a first external electrode electrically connected to said second group of internal electrode layers and insulated from said first group of internal electrode layers by said first insulating films at the first surface of said multilayered structure; and    a second external electrode electrically connected to said first group of internal electrode layers and insulated from said second group of internal electrode layers by said second insulating films at the second surface of said multilayered structure.    
     
     
         2 . The piezoelectric element according to  claim 1 , wherein said first group of internal electrode layers and said second group of internal electrode layers are alternately disposed.  
     
     
         3 . The piezoelectric element according to  claim 1 , wherein said plurality of piezoelectric material layers and said plurality of internal electrode layers are formed by stacking plural sheets, each including a sheet of a piezoelectric material mixed with a binder and a solvent and at least an electrode material formed thereon, and baking the stacked plural sheets.  
     
     
         4 . The piezoelectric element according to  claim 1 , wherein said plurality of piezoelectric material layers are formed by using the aerosol deposition method.  
     
     
         5 . A method of manufacturing a piezoelectric element having a multilayered structure, said method comprising the steps of: 
 (a) fabricating a multilayered structure in which a plurality of piezoelectric material layers and a plurality of internal electrode layers are alternately stacked, said plurality of internal electrode layers including a first group of internal electrode layers and a second group of internal electrode layers;    (b) forming first insulating films for covering said first group of internal electrode layers at a first surface of said multilayered structure by using an aerosol deposition method;    (c) forming second insulating films for covering said second group of internal electrode layers at a second surface of said multilayered structure by using the aerosol deposition method;    (d) forming a first external electrode electrically connected to said second group of internal electrode layers and insulated from said first group of internal electrode layers by said first insulating films at the first surface of said multilayered structure; and    (e) forming a second external electrode electrically connected to said first group of internal electrode layers and insulated from said second group of internal electrode layers by said second insulating films at the second surface of said multilayered structure.    
     
     
         6 . The method of manufacturing a piezoelectric element according to  claim 5 , wherein said first group of internal electrode layers and said second group of internal electrode layers are alternately disposed.  
     
     
         7 . The method of manufacturing a piezoelectric element according to  claim 5 , wherein step (a) includes stacking plural sheets, each including a sheet of a piezoelectric material mixed with a binder and a solvent and at least an electrode material formed thereon, and baking the stacked plural sheets.  
     
     
         8 . The method of manufacturing a piezoelectric element according to  claim 5 , wherein step (a) includes forming said plurality of piezoelectric material layers by using the aerosol deposition method.  
     
     
         9 . The method of manufacturing a piezoelectric element according to  claim 5 , wherein: 
 step (b) includes forming a mask to be used for forming said first insulating films; and    step (c) includes forming a mask to be used for forming said second insulating films.    
     
     
         10 . The method of manufacturing a piezoelectric element according to  claim 9 , wherein the mask formed at at least one of step (b) and (c) includes one of a resist mask and a metal mask.