Abstract
The fracture probability of the multilayered piezoelectric transformer under the high mechanical vibration was investigated. In this work, the fracture stress measured with a mechanical method and the generated stress under driving measured with a electrical method were compared. The tensile strength was calculated from the 3-point bending strength. The fracture stress of the piezoelectric transformer was obtained as 43MPa. The piezoelectric transformers were driven under a loading condition postulated the cold cathode tube and the liquid crystal display panel. The generated stress under driving was obtained from the measurement of vibration velocity. Driving at λ/2 mode (output: 4.2VA), the generated stress would be 26 MPa and the probability of fracture was 8.6×10-3. On the other hand, driving at λ mode (output: 5.3VA), the generated stress would be 16 MPa and the probability of fracture was 1.2×10-4. It is lower than the fracture probability at λ/2 mode.
