Patent ID: 7839054

Claim:
A piezoelectric actuator comprising: a stack of piezoelectric layers formed from a piezoelectric material, a plurality of internal electrodes disposed throughout the stack to define active regions of the piezoelectric material therebetween that are responsive to a voltage applied across two or more groups of the internal electrodes in use, an insulating arrangement that at least partially covers at least one surface of the stack to define a piezoelectric/insulator interface, and two or more side electrodes to connect with the two or more groups of the internal electrodes; wherein a bridging arrangement extends through the insulating arrangement, the bridging arrangement comprising a conductive material so as to provide a connection between a side electrode and an internal electrode, and wherein at least one first surface, defined by an interface between the conductive material and the insulating arrangement, and at least one second surface, defined by an internal boundary of a piezoelectric layer, are substantially continuous with one another in the vicinity of the piezoelectric/insulator interface; wherein the internal boundary of a piezoelectric layer is defined by an interface between the piezoelectric material and the conductive material and wherein the first and second surfaces share a common tangent at the piezoelectric/insulator interface; characterized in that the bridging arrangement comprises a slot being a ‘v’ shaped groove.