| 摘要 |
PROBLEM TO BE SOLVED: To detect the state of a piezoelectric element. SOLUTION: A piezoelectric element 100 has counter electrodes 12, 14 arranged at both the sides of a laminated layer comprising internal electrodes 18 and thin plates 16 of a piezoelectric material, a control voltage from a power supply 24 is applied to the piezoelectric element and the piezoelectric element 100 is deformed. And detection electrodes 20, 22 are arranged at the outer side of the counter electrodes 12, 14 of the piezoelectric element 100, and an induced electric charge induced to the electrodes is detected by a charge amplifier 26. Since the induced electric charge has a linear relation with the amount of deformation of the piezoelectric element 100, the state such as the amount of the piezoelectric element 100 can be detected by the output of the charge amplifier 26. |
