Patent ID: 6759792
Filing Date: 2004-07-06
Classification: H01L,Y10T

Abstract:
A polarization method of a multi-layered piezoelectric body in which a plurality of piezoelectric layers and a plurality of internal electrodes are alternately laminated and adjacent piezoelectric layers are polarized in the thickness direction thereof such that the polarization directions thereof are in opposite directions; comprising steps of:a first polarization process in which an electric field in a first thickness direction is applied to the multi-layered piezoelectric body and the polarization is uniformly performed in the first thickness direction, a secondary polarization process in which an electric field in a second thickness direction that is opposite to the first thickness direction is applied to the piezoelectric layers of both sides of the internal electrodes and the direction of polarization of the piezoelectric layer on only one side of the internal electrode is reversed; wherein the secondary polarization process is performed in a range such that a remaining polarization degree Pr2 that exists after the secondary polarization process in the piezoelectric layer having a direction of polarization that is reversed does not exceed a remaining polarization degree Pr1 after the first polarization.