Piezoelectric/electrostrictive device

Abstract

A piezoelectric/electrostrictive device includes a pair of thin plates confronting each other, a fixing member supporting the thin plates thereon, and movable portions disposed on end portions of the pair of thin plates. Protrusions are formed on principal surfaces of first ceramic green sheets according to at least a single thick film forming process. The protrusions will subsequently serve as the movable portions, and the first ceramic green sheets will subsequently serve as the thin plates. The first ceramic green sheets and a second ceramic green sheet which will subsequently serve as the fixing member are stacked into a ceramic green laminated body. The ceramic green laminated body is baked into an integral ceramic laminated body. Piezoelectric/electrostrictive elements are formed on the ceramic laminated body. After the piezoelectric/electrostrictive elements are baked, unnecessary-portions are removed from the piezoelectric/electrostrictive elements to fabricate the piezoelectric/electrostrictive device.

1 . A piezoelectric/electrostrictive device including a pair of thin plates confronting each other, a fixing member supporting the thin plates thereon, and protrusions functioning as movable portions disposed on end portions of the pair of thin plates, wherein the protrusions have a width (L) of 30 μm or greater.  
   
   
       2 . A piezoelectric/electrostrictive device according to  claim 1 , wherein the protrusions have a thickness (H) in the range from 2 to 50 μm.  
   
   
       3 . A piezoelectric/electrostrictive device according to  claim 1 , wherein the protrusions include a peripheral portion having a thickness H 1  and a central thickest portion having a thickness H 2 , and the thicknesses have a ratio as follows:  
         H   1 / H   2 =⅓ to ¾.  
   
   
       4 . A piezoelectric/electrostrictive device according to  claim 1 , wherein the protrusions include a central portion having a thickness H 1  and a peripheral thickest portion having a thickness H 2 , and the thicknesses have a ratio as follows:  
         H   1 / H   2 =⅓ to ¾.  
   
   
       5 . A piezoelectric/electrostrictive device according to  claim 1 , wherein the protrusions have a two-step structure including a first protrusion and a second protrusion partly overlapping one another.  
   
   
       6 . A piezoelectric/electrostrictive device according to  claim 5 , wherein at least one of the first protrusion and the second protrusion has a thickness H 1 , a thickest portion of an overlapping region of said at least one of the first protrusion and the second protrusion has a thickness H 2 , and the thicknesses have a ratio as follows:  
         H   1 / H   2 =⅓ to ¾.  
   
   
       7 . A piezoelectric/electrostrictive device according to  claim 5 , wherein an overlapping region of the first protrusion and the second protrusion has a thickness H 1 , a thickest portion of at least one of the first protrusion and the second protrusion has a thickness H 2 , and the thicknesses have a ratio as follows:  
         H   1 / H   2 =⅓ to ¾.  
   
   
       8 . A piezoelectric/electrostrictive device according to  claim 1 , wherein the protrusions include a plurality of protrusions separated from each other.  
   
   
       9 . A piezoelectric/electrostrictive device according to  claim 1 , wherein the protrusions include a cermet.  
   
   
       10 . A piezoelectric/electrostrictive device according to  claim 9 , wherein a metal material included in the cermet comprises a platinum-group metal.  
   
   
       11 . A piezoelectric/electrostrictive device according to  claim 1 , wherein the protrusions have a porosity of 50% or less.  
   
   
       12 . A piezoelectric/electrostrictive device according to  claim 1 , wherein the protrusions have a porosity in the range from 5 to 30%.