Piezoelectric/electrostrictive film element and method of producing the same

A piezoelectric/electrostrictive film element comprising:

• a ceramic substrate having at least one window, and a diaphragm portion closing each of said at least one window, said diaphragm portion being formed as an integral part of said ceramic substrate;
• and
• a piezoelectric/electrostrictive unit including a lower electrode, a piezoelectric/electrostrictive layer and an upper electrode, which are formed in the order of description on an outer surface of said diaphragm portion by a film-forming method, to provide a laminar structure, said piezoelectric/electrostrictive layer consisting of a dense body having a crystal grain size of not smaller than 0.7 .mu.m, and a porosity (x) of not greater than 15%, said diaphragm portion having a deflection percentage (y) of 0-8%, which is a percentage of an amount of deflection of a central part of said diaphragm portion into the window in an unbiased state, with respect to a length of a shortest line which extends across a corresponding one of said at least one window and passes through a center of the window, said porosity (x) and said deflection percentage (y) satisfying the following formula:
• y.ltoreq.0.1167x.sup.2 -3.317x+25.5.