Piezoelectric Actuator

摘要

A piezoelectric actuator comprises a co-fired stack (10) of piezoelectric elements (12) formed from a piezoelectric material and a plurality of positive internal electrodes (14) intcrdigitatcd with a plurality of negative internal electrodes (16) throughout the stack (10) to define active regions (22) of the piezoelectric material which are responsive to a voltage applied across the internal electrodes (14), in use. An external positive electrode (18) connects with the positive internal electrodes (14) and an external negative electrode (20) connects with the negative internal electrodes (16). The actuator stack (10) further comprises means (38a, 38b) for deliberately creating artificial cracks (36) within the stack (10) at a location at which the artificial cracks do not give rise to a short circuit between the internal electrodes (14, 16) but serve to relieve stresses within the piezoelectric material. The actuator is characterised in that the means for deliberately creating artificial cracks comprises at least one void region (40) within the stack (10) which is substantially free from piezoelectric material.