| 摘要 |
PROBLEM TO BE SOLVED: To provide a piezoelectric transformer that has a small size, can be manufactured easily, and can obtain a high boosting magnification. SOLUTION: Input electrodes are formed on both broad end sides of an hourglass-shaped piezoelectric ceramic plate that commonly uses the narrow end face of a trapezoidal piezoelectric ceramic substrate and an output electrode is formed at a narrow central portion of the ceramic plate. Two trapezoidal portions are driven in opposite phases by selecting a proportion which makes the displacement of the central narrow portion very small. A boosting magnification that is almost equal to that of the conventional laminated type piezoelectric transformer can be obtained by driving the trapezoidal portions in a contour vibrating mode in which one trapezoidal portion elongates and the other portion shrinks. Either one of a single piezoelectric ceramic plate and a piezoelectric ceramic substrate the output side of which is connected can be used. The characteristics of this piezoelectric transformer can be improved by selecting the ratio of the widths of both ends to that of the central portion.
|
