Piezoelectric device

Abstract

A piezoelectric device that includes: a diaphragm; a supporting part configured to support at least a portion of an end of the diaphragm; a piezoelectric film disposed along a portion supported by the supporting part on the diaphragm, a width of the film along the supported portion being narrower than a width of the portion; a lower electrode disposed at a face of the piezoelectric film on a diaphragm side; and an upper electrode disposed on a face of the piezoelectric film on an opposite side to the diaphragm.

I (We) claim: 
     
         1 . A piezoelectric device comprising:
 a substrate;   a plurality of transducer beams, each of the plurality of transducer beams comprising:
 a piezoelectric layer; 
 a first electrode layer; and 
 a second electrode layer, the first and second electrode layers sandwiching the piezoelectric layer, wherein 
   each of the plurality of transducer beams have a beam base, a beam end, and a beam body between the beam base and the beam end,   the plurality of transducer beams are connected in a cantilever arrangement over the substrate with each of the beam bases of the plurality of transducer beams attached to the substrate, and   each of the beam ends of the plurality of transducer beams converge towards a single point such that at least two of the beam ends face each other and are separated by a gap.   
     
     
         2 . The piezoelectric device according to  claim 1 , wherein a width of the piezoelectric film is narrower than a width of the second electrode layer. 
     
     
         3 . The piezoelectric device according to  claim 1 , wherein the second electrode layer is formed of a degenerate semiconductor. 
     
     
         4 . The piezoelectric device according to  claim 1 , further comprising a third electrode between the piezoelectric layer and the second electrode. 
     
     
         5 . The piezoelectric device according to  claim 1 , wherein
 the piezoelectric film has a compressive stress, and   the upper electrode has a tensile stress.   
     
     
         6 . The piezoelectric device according to  claim 1 , wherein the substrate includes a supporting part and an insulating layer. 
     
     
         7 . The piezoelectric device according to  claim 6 , wherein the insulating layer is adjacent the beam bases of the plurality of transducer beams. 
     
     
         8 . The piezoelectric device according to  claim 7 , wherein the insulating layer is silicon oxide. 
     
     
         9 . The piezoelectric device according to  claim 1 , wherein the plurality of transducer beams are electrically coupled in parallel to each other. 
     
     
         10 . The piezoelectric device according to  claim 1 , wherein the plurality of transducer beams are electrically coupled in series to each other. 
     
     
         11 . The piezoelectric device according to  claim 1 , wherein
 a first set of the plurality of transducer beams are electrically coupled in parallel to each other,   a second set of the plurality of transducer beams are electrically coupled in parallel to each other, and   the first and second sets of the plurality of piezoelectric films are electrically coupled in series to each other.   
     
     
         12 . The piezoelectric device according to  claim 1 , wherein
 a first set of the plurality of transducer beams are electrically coupled in series to each other,   a second set of the plurality of transducer beams are electrically coupled in series to each other, and   the first and second sets of the plurality of transducer beams are electrically coupled in parallel to each other.