To provide a highly reliable piezo-electric transformer case of a simple structure which, despite a narrow space between the piezo-electric transformer and a circuit board, is capable of securing an enough dielectric strength voltage, preventing discharge and maintaining transforming efficiency.
A sheet 30 made of an insulating material is laid in a predetermined area at the bottom of a case body 10 to accommodate the piezo-electric transformer 50. Except where an output electrode 52 of the piezo-electric transformer 50 is connected to a wiring pattern of the circuit board through a lead terminal 20, the wiring pattern which is overlapped with the case body 10 and the piezo-electric transformer 50 are in a state to sandwich the case body 10 and the sheet 30. Thus, a predetermined withstand voltage higher than a maximum output voltage is secured between the wiring pattern and the piezo-electric transformer 50 and, irrespective of the shape of the bottom of the case body 10, the wiring pattern and the piezo-electric transformer 50 are insulated sufficiently, resulting in preventing the danger of discharge arising between the piezo-electric transformer 50 and the wiring pattern, or the like and increasing reliability.
NAKAJIMA HIDEFUMI
ABE KINICHI
