Patent ID: 7100254

Claim:
A method of manufacturing a piezoelectric actuator, which generates pressure in each pressure chamber of a pressure chamber forming unit on which pressure chambers formed of multiple concave parts are provided on one surface, comprising: a first process comprising: forming a first sheet formed of pliant piezoelectric materials and a second sheet formed of pliant materials, forming an upper electrode layer formed of conduction materials on one surface of said first sheet, and forming a lower electrode layer formed of conduction materials on the other surface of said first sheet or one surface of said second sheet, wherein an electrode layer for polarization formed of conduction material is formed on the other surface side of said second sheet; a second process comprising piling and densifying said first and second sheets having said lower electrode layer between; a third process comprising polarizing said first sheet in a direction of a thickness of the first sheet; and a fourth process comprising patterning said upper electrode layer in order to form multiple electrodes corresponding respectively to each said pressure chamber of said pressure chamber forming unit, wherein the upper electrode layer and electrode layer for polarization are located external to any other layers of the actuator, such that by placing a voltage across a face surface of said upper electrode layer and a face surface of said electrode layer for polarization, said first sheet is polarized in the direction of a thickness of the first sheet, whereby warping of the actuator during polarization is reduced.