Patent ID: 7948150

Claim:
A piezoceramic multilayer actuator comprising: a plurality of piezoceramic layers comprising a piezoceramic first material sintered at a sintering temperature; and a security layer disposed between two piezoceramic layers such that the two piezoceramic layers on opposing sides of the security layer are substantially fully separated from each other by the security layer; and wherein the security layer comprises a second material and particles at least partially embedded in the second material, wherein the particles comprise a third material different from the first material and different from the second material, and wherein a weakened connection between the security layer and at least one adjacent piezoceramic layer is created due to at least one of the following: (a) the third material is more brittle than the first material and the second material, (b) gaps are formed at an interface between the security layer and a piezoceramic layer that degrade the mechanical connection of the security layer and the piezoceramic layer, and (c) the first material or the second material are locally mechanically degraded at interfaces between the first material or the second material, respectively, and the particles.