Patent ID: 7268473

Claim:
A piezoelectric actuator having a stack body comprising a plurality of piezoelectric elements, each element having a positive and negative electrode pair which are electrically isolated from one another by the piezoelectric elements, the electrode pairs being arranged in groups of one or more electrode pairs, each group having a conducting arrangement in electrical connection therewith, the piezoelectric actuator further comprising a distribution electrode arrangement for connecting the conducting arrangement to a power supply, in use, wherein the distribution electrode arrangement includes a fuse arrangement whereby, in the event of a short circuit between electrodes of a pair within one of the groups, the fuse arrangement breaks the electrical connection between the power supply and the conducting arrangements; wherein the distribution electrode arrangement includes a first distribution electrode associated with the positive electrode and a second distribution electrode associated with the negative electrode; and wherein each of the first and second distribution electrodes includes an insulating substrate having first and second opposing side faces, a conducting member disposed on the first face of the insulating substrate and a plurality of charge distribution elements disposed on the second face of the insulating substrate.