Patent ID: 6812623
Filing Date: 2004-11-02
Classification: H01L,H05B

Abstract:
A piezoelectric transformer comprising:a rectangular plate made of a piezoelectric material; and primary electrodes and secondary electrodes each formed on said rectangular plate; wherein said rectangular plate comprises a plurality of piezoelectric layers layered successively in a thickness direction of said rectangular plate; said primary electrodes are provided by layering said plurality of piezoelectric layers and a plurality of electrode layers in the thickness direction of said rectangular plate, said plurality of electrode layers comprising electrodes to provide a plurality of groups of electrodes in the longitudinal direction of said rectangular plate; said plurality of groups of electrodes comprise a first group of electrodes formed in a central portion in the longitudinal direction of said rectangular plate, and a second group of electrodes and a third group of electrodes formed adjacent to said first group of electrodes and on one side and on the other side of said first group of electrodes in the longitudinal direction of said rectangular plate, respectively; said first, second and third groups of electrodes are formed symmetrically with respect to a center line perpendicular to the longitudinal direction of said rectangular plate and dividing said rectangular plate in half in the longitudinal direction of said rectangular plate; and said secondary electrodes are formed near the two ends of the rectangular plate in the longitudinal direction of said rectangular plate; whereby a voltage is output from said secondary electrodes when an alternating voltage is applied to said primary electrodes to excite mechanical vibrations of a 3/2 wavelength to expand and contract said rectangular plate in a longitudinal direction thereof in said rectangular plate.