US Patent 7383621 Method of producing a piezoelectric ceramic

A piezoelectric contains comprises a plurality of piezoelectric particles made from a piezoelectric material such as lead titanate zirconate and a dielectric made from a dielectric material, such as a composite perovskite compound, having a higher dielectric constant then the piezoelectric material, the dielectric existing in gaps between the piezoelectric particles. When poling to produce a piezoelectric ceramic, the poling is uniformly performed, and nearly all of the electric field is applied to the piezoelectric particles. Thus, the dispersion of the piezoelectric properties can be reduced, and the piezoelectric properties can be enhanced.