Patent ID: 8358051
Filing Date: 2013-01-22
Classification: H01L,Y10T

Abstract:
1. A piezoelectric actuator comprising: a stack of piezoelectric elements formed from a piezoelectric material, a plurality of positive internal electrodes interdigitated with a plurality of negative internal electrodes throughout the stack to define active regions of the piezoelectric material that are responsive to a voltage applied across the internal electrodes, in use, an external positive electrode for connection with the positive internal electrodes, and an external negative electrode for connection with the negative internal electrodes, wherein the stack further comprises means for deliberately creating artificial cracks within the stack at a location at which the artificial cracks do not give rise to a short circuit between the internal electrodes but serve to relieve stresses within the piezoelectric material, and wherein the means for deliberately creating artificial cracks includes a plurality of intermediate layers of non-conductive material extending across the full width of the stack from the external positive electrode to the external negative electrode, said intermediate layers distributed throughout the stack; wherein said intermediate layers are formed from a material having a higher sintering temperature than the piezoelectric material.