Piezoelectric-transducer energy harvester, in particular for powering an autonomous cardiac capsule, with a bending stiffness gradient oscillating structure

Abstract

The harvester comprises a pendular unit comprising a beam that is elastically deformable in bending, a mount clamping a proximal end of the beam, and an inertial mass mounted at a free, distal end of the beam. The beam converts into an oscillating electric signal a mechanical energy produced by pendular unit oscillations. The beam comprises a flexible structure including a central core, a piezoelectric layer on at least one face of the central core, and at least one surface electrode on an external face of the piezoelectric layer. The central core of the flexible structure is made of a semiconductor material adapted to form an integrated circuit substrate. The substrate made of a semiconductor material of the central core includes monolithic integrated structures, and the arrangement, over the extend of the central core substrate, of said integrated structures forms in the longitudinal direction a plurality of successive areas having different bending stiffness coefficients from an area to another.