US Patent 7530673 Actuator device, liquid-jet head and liquid-jet apparatus

An actuator device including vibration plates formed on one side of a substrate; and piezoelectric elements mounted through the vibration plates and each including a lower electrode, a piezoelectric layer, and an upper electrode, wherein a ratio d31/S11E of a piezoelectric constant d31 of the piezoelectric layer to an elastic compliance S11E of the piezoelectric layer is greater than 5 C/m2, and the elastic compliance S11E of each vibration plate is greater than 2×10−8 m2/N.