Patent ID: 7695117

Claim:
A method for manufacturing a piezoelectric actuator which includes a piezoelectric layer having a predetermined active portion, the method comprising: providing a vibration plate; providing a piezoelectric layer on a surface of the vibration plate; forming a first polarizing electrode on one surface of the piezoelectric layer, at a central portion of a first area of the piezoelectric layer, the first area overlapping with a predetermined active area to be the active portion of the piezoelectric layer; forming a second polarizing electrode on the one surface of the piezoelectric layer at an edge portion of the first area, the edge portion being different from the central portion; forming a first electrode on the other surface of the piezoelectric layer, at a second area overlapping entirely with the active area of the piezoelectric layer; polarizing a first portion of the piezoelectric layer in a predetermined direction by applying an electric field in the predetermined direction to the first portion which is arranged between the first electrode and the first polarizing electrode; polarizing a second portion of the piezoelectric material layer in an opposite direction opposite to the predetermined direction by applying an electric field in the opposite direction to the second portion which is arranged between the first electrode and the second polarizing electrode; and forming a second electrode, on the other surface of the piezoelectric layer, at a portion of the second area; wherein the first polarizing electrode and the second polarizing electrode are formed to be mutually isolated, and the first portion and the second portion are polarized simultaneously.