Patent ID: 7681989
Filing Date: 2010-03-23
Classification: B41J,Y10T

Abstract:
1. A piezoelectric actuator for an ink-jet printhead, formed on a flow path plate having a pressurizing chamber, the piezoelectric actuator for applying a driving force for ink ejection to the pressurizing chamber, the piezoelectric actuator comprising: a lower electrode on the flow path plate; a bonding pad on the flow path plate to be insulated from the lower electrode, wherein a driving circuit for voltage application is bonded to an upper surface of the bonding pad; a piezoelectric layer on the lower electrode at a position corresponding to the pressurizing chamber, wherein an end of the piezoelectric layer extends onto the bonding pad; an upper electrode directly on an upper surface of the piezoelectric layer, wherein an end of the upper electrode extends beyond the end of the piezoelectric layer to be in direct contact with an entire side surface of the piezoelectric layer and in direct contact with the upper surface of the bonding pad; and a trench bounding the bonding pad, the trench extending through the lower electrode, wherein the bonding pad is insulated from the lower electrode by the trench, and the trench extends from an upper surface of the lower electrode to a predetermined depth in the flow path plate, the predetermined depth of the trench being sufficient to overlap a portion of the pressurizing chamber, and the trench including a cavity at a bottom surface of the trench.