| 摘要 |
PURPOSE: To prevent a crack from being generated when a voltage is applied in a polarization operation and to increase a step-up ratio when a comb-shaped electrode is used as an electrode for input-voltage application in a piezoelectric transformer having a structure in which the electrode for input-voltage application and an electrode for output-voltage application are formed on the surface of a piezoelectric body. CONSTITUTION: The polarization treatment of a drive part 10 and a power generation part 21 is executed at two stages in such a way that the power generation part 10 is first polarized in the length direction of a piezoelectric ceramic plate 1 at a high temperature and a low electric field and that the drive part 21 is then polarized in the thickness direction of the piezoelectric ceramic plate 1 at a lower temperature and a higher electric field than in the first polarization treatment. When a comb-shaped electrode is used as an electrode for input-voltage application, an edge electrode for polarization treatment is installed at the edge of the drive part, a voltage is first applied across the comb-shaped electrode and the edge electrode, the power generation part and the drive part are polarized simultaneously in the length direction, electrode fingers at the comb-shaped electrode in the drive part are then inversion-polarized every other finger, and a step-up ratio can be increased. |
