Patent ID: 7355326

Claim:
A piezoelectric transformer operating in a half wavelength mode, comprising: an input part having input electrodes laminated in a thickness direction on a central part in a longitudinal direction of a piezoelectric element with rectangular shape; a pair of output parts provided so as to sandwich said input part along said longitudinal direction; and an output electrode provided at an end part of each of said output parts, wherein said input part is polarized in the thickness direction between the input electrodes, and said output parts are polarized in the same direction along said longitudinal direction; and wherein L 1 , L 2 and L 3 satisfy a relation of 0.1â‰¦(4L 2 âˆ’L 3 )/4L 1 â‰¦0.5, where L 1 is a length of said piezoelectric element in its longitudinal direction, L 2 is a length of said input part in said longitudinal direction, and L 3 is a length of either one of said output electrodes in said longitudinal direction.