Piezoelectric transformer, piezoelectric transformer drive circuit, piezoelectric transformer drive method and cold cathode tube drive apparatus using piezoelectric transformer

A piezoelectric transformer comprising:

• a rectangular plate having its longitudinal direction as its main direction thereof and mainly formed of a piezoelectric material,
• a drive portion having a set of primary electrodes formed on the opposite faces of said rectangular plate in the direction of the thickness thereof and at a region retracted from an end face of said rectangular plate in the longitudinal direction thereof,
• a power generation portion having a set of secondary electrodes formed on said rectangular plate, and
• a set of third electrodes formed on the opposite faces of said rectangular plate in the direction of the width thereof and adjacent to a region from which said primary electrodes are retracted.