Patent ID: 6107726
Filing Date: 2000-08-22
Classification: H01L

Abstract:
A piezoelectric linear actuator comprising:a unitary densified, rigid, monolithic, poled piezoelectric or electrostrictive ceramic body, said body comprising a top, four sides generally normal to and interconnected with said top, a base generally normal to and interconnected with said sides, and two or more ceramic layers including a top ceramic layer providing said top, a bottom ceramic layer providing said bottom, and, optionally, one or more intermediate ceramic layers, said layers being superimposed over one another;wherein each ceramic layer except said top ceramic layer is joined at a first of said sides to one of said ceramic layers adjacent thereto by a first ceramic bridge and each ceramic layer except said bottom ceramic layer is joined at a second of said sides opposite said first side to another of said ceramic layers adjacent thereto by a second ceramic bridge; andwherein first and second cavities extend into said ceramic body from said first and second sides, respectively, said first cavities alternating with said second cavities in said ceramic body, such that said ceramic body has a serpentine cross-section; said body further comprisinga first electrode and a second electrode, each of an electrically conductive material, said first and second electrodes being disposed along and bonded to said first and second sides, respectively, of said body;wherein said body is poled and electroded in a d.sub.33 or d.sub.15 configuration to effect linear expansion of said actuatorin a direction normal to said ceramic layers; said first and second electrodes extend into said first and second cavities, respectively, to provide internal electrode portions for each electrode; said internal electrode portions are bonded to said ceramic layers in said first and second cavities; each of said first and second electrode portions defines an electrode cavity internal to said first and second cavities, respectively; and said first electrode internal electrode portions alternate with said second electrode portions such that each of said electrodes has a continuous serpentine cross-section.