Abstract: An actuator device comprises an actuator element which has a shortest length when no electric voltage is applied and which is increased in length as an electric voltage applied thereto becomes higher, a displacement extracting part 17, and a converter mechanism for carrying out conversion of converting the change in length of the actuator element 11 into the displacement of the displacement extracting part 17. The converter mechanism comprises holders 14 and 13 and a transmission member 16 and carries out the conversion so that the displacement of the displacement extracting part 17 is decreased as the length of the actuator element 11 is increased. The converter mechanism carries out the conversion so that the displacement of the displacement extracting part 17 becomes maximum when the actuator element 11 has the shortest length.

Abstract: A stacked-type piezoelectric actuator includes a rectangular stack body having a plurality of piezoelectric ceramic layers and a plurality of internal electrode layers stacked alternately in a stacking direction. Alternate internal electrode layers disposed in the stacking direction are only exposed in two outer side surfaces of the stack body, while the alternate internal electrode layers are exposed in the other two outer side surfaces of the stack body. Two external electrodes are formed on opposite ones of the four outer side surfaces of the stack body. Thus, alternate internal electrode layers are connected to one of the external electrodes but electrically insulated from the other external electrodes. While the other internal electrode layers are insulated from the external electrodes and are connected to the other one of the external electrodes.

Abstract: In a mechanical amplification mechanism for piezoelectric elements, a pair of lever arms, base block and a pair of fulcrum portions connecting therebetween are structured with a lamination of thin metal plates of a predetermined number. Each of thin metal plate has the thickness smaller than the width of the fulcrum portions and they are laminated such that the total thickness is larger than the width of the fulcrum portions. The lamination strength of thin metal sheets is improved by either caulking predetermined positions or inserting a bonding material between every thin metal plates.