| 摘要 |
A piezoelectric device comprises a piezoelectric element including a piezoelectric layer formed of a complex oxide having a perovskite structure including bismuth, iron, barium, and titanium, and a pair of electrodes placing the piezoelectric layer therebetween. The piezoelectric element is driven with a first drive mode and a second drive mode. In the first drive mode, the piezoelectric element is driven at a first speed, and is held to a first voltage V1 in a first hold process during a first time defined based on a natural period Tc. In the second drive mode, the piezoelectric element is driven at a higher speed than the first speed, and is held to the first voltage V1 in the first hold process during a second time shorter than the first time, and an intermediate voltage Vm is set to be equal to or lower than a voltage corresponding to the coercive electric field Ec. |
| 主权项 |
1. A piezoelectric device having a natural period Tc and a coercive electric field Ec, the piezoelectric device comprising:
a piezoelectric element including a piezoelectric layer formed of a complex oxide having a perovskite structure including bismuth, iron, barium, and titanium, and a pair of electrodes placing the piezoelectric layer therebetween; and a driver supplying a drive waveform to the piezoelectric element, the drive waveform including:
a standby process of applying intermediate voltage Vm to the piezoelectric element in a standby state;a first voltage change process of changing the voltage applied to the piezoelectric element from the intermediate voltage Vm to a first voltage V1 having a polarity opposite to a polarity of the intermediate voltage Vm;a first hold process of holding the voltage applied to the piezoelectric element to the first voltage V1;a second voltage change process of changing the voltage applied to the piezoelectric element from the first voltage V1 to a second voltage V2 having a polarity same as the intermediate voltage Vm and higher value than the intermediate voltage Vm; anda second hold process of holding the voltage applied to the piezoelectric element to the second voltage V2, wherein, the piezoelectric element is driven with a first drive mode and a second drive mode, wherein, in the first drive mode, the piezoelectric element is driven at a first speed, and is held to the first voltage V1 in the first hold process during a first time defined based on the natural period Tc, and wherein, in the second drive mode, the piezoelectric element is driven at a higher speed than the first speed, and is held to the first voltage V1 in the first hold process during a second time shorter than the first time, and the intermediate voltage Vm is set to be equal to or lower than a voltage corresponding to the coercive electric field Ec. |
