| 摘要 |
A piezoelectric device (10), which has bipolar polarization-electric field (Pr-E) hysteresis characteristics of a piezoelectric material asymmetrically biased, when a first coercive electric field having smaller absolute value is defined as Ec1 and a second coercive electric field having larger absolute value is defined as Ec2 and a bias ratio of the coercive electric field is defined as [(Ec2+Ec1)/(Ec2-Ec1)]×100[%], includes a piezoelectric element unit (28) in which a piezoelectric body film (42) whose bias ratio is equal to or more than 20% is used, the piezoelectric element unit (28) operating with an electric field intensity smaller than that of the first coercive electric field. The piezoelectric device (10) includes a refresh voltage applying circuit (36) configured to apply a voltage in order to maintain operation performance of the relevant device, the voltage having an electric field intensity larger than the electric field intensity for operating the device and being equal to or less than three times an absolute value |Ec1| of the first coercive electric field, such that a polarized state of the piezoelectric body film (42) is restored. |
