Planar spring assembly with attached solder strip and method for making same

Abstract

There is disclosed for use with a piezoelectric stack, first and second side electrodes, each side electrode having two serpentine shape members positioned in a common plane, where the two serpentine shape members of an electrode have alternately spaced conductive fingers which project outward toward each other. The conductive fingers are adapted to be electrically coupled to the ends of alternate ones of internal electrode layers of the piezoelectric stack. The undersides of the conductive fingers which contact the ends of the internal electrodes are provided with a solder material to provide good electrical contact by applying the soldered finger to the internal electrode and applying heat to reflow the solder. The serpentine shape of the side electrodes here disclosed provides high flexibility which can absorb displacement of the internal electrodes as they move up, down, in and out as the piezoelectric layers of the stack expand and contract. This flexibility helps to avoid electrical contact separation between the side electrodes and the internal electrodes.