Patent ID: 6597085
Filing Date: 2003-07-22
Classification: H01L

Abstract:
A piezoelectric transformer having a piezoelectric workpiece for converting an input electrical power of one voltage into an output electrical power of another voltage, said piezoelectric workpiece is an elongated thin plate comprising:an actuator section formed in said piezoelectric workpiece having a modal-shaped electrode for exciting said piezoelectric workpiece into mechanical vibration upon driven by said input electrical power, and a sensor section formed in said piezoelectric workpiece having a sensor electrode for delivering said output electrical power to an external load of said transformer by picking up the power generated by said exciting, wherein: said modal-shaped actuator electrode having a shape function defined by the mathematical solution function e31&it;(x)e310=sin&it;â€ƒ&it;n&it;â€ƒ&it;Ï€&it;â€ƒ&it;xlof the governing equation -Ï &it;&PartialD;2&it;u&PartialD;t2+c11E&it;&PartialD;2&it;u&PartialD;x2=E3in&it;&PartialD;e31&PartialD;xof said piezoelectric workpiece under the condition &PartialD;e31&PartialD;x=k&it;â€ƒ&it;&varphi;n&it;(x)that said piezoelectric workpiece being vibrating in a selected resonant mode, whereine31 is the piezoelectric stress/charge constant; u is the longitudinal strain function; &phgr;i(x) is the characteristic function; l is the effective length; x is the longitudinal dimension variable; t is the time variable; k is a scale factor; and n is the selected resonant mode of operation.