Patent ID: 8575822

Claim:
A piezoelectric/electrostrictive actuator, which comprises: a piezoelectric/electrostrictive element that comprises at least one laminate including one piezoelectric/electrostrictive layer and one pair of electrodes disposed respectively on both sides of said piezoelectric/electrostrictive layer and has a moving part corresponding to a portion where said piezoelectric/electrostrictive layer is sandwiched by one pair of said electrodes and a non-moving part corresponding to a portion where said piezoelectric/electrostrictive layer is not sandwiched by one pair of said electrodes, and a moistureproof membrane disposed to cover at least the proximity of the boundary between said moving part and said non-moving part and consisting of a silicone-based organic insulation material with a storage elastic modulus of 100 kPa or less obtained by dynamic viscoelastic measurement using a parallel cone with a diameter of 25 mm under a condition with a strain of 0.1%, a frequency of 1 Hz, a gap of 0.5 mm and a temperature of 22° C.