Piezoelectric actuator

Abstract

The piezoelectric actuator includes a piezoelectric element (2) including a sheet of piezoelectric ceramic and electrodes formed at least part of the surface of the sheet of piezoelectric ceramic, and a holding member (4) holding the piezoelectric element (2); The piezoelectric at least one of the requirements (a) to (e) described below; (a) The bulk density shall be equal to or smaller than 5 g/cm3, and the Young's modulus Y11E calculated according to a resonance-antiresonance method shall be equal to or larger than 90 GPa; (b) The coefficient of thermal conductivity shall be equal to or larger than 2 Wm−1K−1; (c) The coefficient of thermal expansion shall be equal to or larger than 3.0 ppm/° C. over a temperature range from −30° C. to 160° C.; (d) The pyroelectric coefficient shall be equal to or smaller than 400 μCm−2K−1 over the temperature range from −30° C. to 160° C.; (e) The mechanical quality factor Qm calculated according to the resonance-antiresonance method shall be equal to or smaller than 50 over a temperature range from −30° C. to 80° C.

Dependencies are inferred from the claim text.