Patent ID: 6921157

Claim:
A piezoelectric actuator comprising: a piezoelectric actuator main body having a bottom electrode, a piezoelectric element formed on said bottom electrode, and a top electrode, formed on said piezoelectric element, for impressing voltage on said piezoelectric element together with said bottom electrode, a cap member for enclosing at least a surface of said piezoelectric actuator main body on the side of said top electrode, and a moisture absorbent disposed in a closed space between said piezoelectric actuator main body and said cap member and having, as an indication of the efficiency of absorbing moisture, a coefficient of moisture absorption of not less than 5 wt. % in a measurement environment of 25° C., 1 atm, and 80% relative humidity, wherein the amount of moisture absorbed into said moisture absorbent is not less than 0 wt. % nor more than 20 wt. %.