PIEZOELECTRIC TRANSFORMER, PIEZOELECTRIC TRANSFORMER UNIT, INVERTER CIRCUIT, LIGHT EMISSION CONTROLLER, AND LIQUID CRYSTAL DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a piezoelectric transformer that is adaptable to cold cathode tube loads, high in effective coupling coefficient, low in loss, and small in size by using a piezoelectric plate having a single direction of polarization. SOLUTION: The value of the electrostatic capacitance formed between a first electrode section 12 and a third electrode section 15a constituting a high impedance section can be adjusted easily in accordance with a load by controlling the dimension of the third electrode section 15a. In addition, since the area of a second electrode section 13 constituting a low impedance section is almost equal to that of a fourth electrode section 15b and the third and fourth electrodes sections 15a and 15b are integrally formed, the efficiency of energy propagation can be improved. Consequently, the transformer can maintain a high element efficiency and a small quantity of heat and, in addition, can reduce distortion, because the transformer can maintain the high effective coupling coefficient resulting from the electrode structure and mode of oscillation even when the value of the electrostatic capacitance is changed arbitrarily.