A piezoelectric acoustic sensor including stress-transferring arches to protect the elements at the lateral side surfaces. An array of parallel rod-like or blade-shaped elements is formed from a dense, poled, strongly piezoelectric or electrostrictive ceramic material. The array is encapsulated in a matrix, e.g., a polymeric matrix, to form a two-phase ceramic/polymer composite body exhibiting 1-3 or 2-2 connectivity. The upper and lower ends of the elements are exposed at upper and lower planar surfaces of the composite body to electrically contact upper and lower electrodes. A stiff portion, e.g., a face plate, extends across each of the upper and lower electroded surfaces, each extending to the edge surfaces of the composite body. A convex-shaped, stress-transferring arch is rigidly anchored to at least one edge of each stiff portion. Hinge portions of each arch at the edges of the stiff portions has a thickness of 0-10 mm. The arches are formed of a material having a stiffness of at least Shore D 80, and are shaped and disposed to direct ambient lateral stress toward the stiff portions, decoupling the ceramic elements from ambient lateral stress and forming a stress resistant piezoelectric acoustic sensor.
A tire monitor includes a first device (300) having at least one piezoelectric matrix element (404), and a first sensing layer (410) that includes at least one rectifier (106) and a processor element (110). The first device (300) is capable of sensing a deflection (u) in a layer of material, and is capable of processing the sensed deflection. The first device (300) is capable of wirelessly transmitting an indication (116) on a condition of the material.
The present invention relates to composite piezoelectric apparatus, transducers and methods of manufacture. In an embodiment, a composite piezoelectric apparatus has a sacrificial base and pillar array. Different volume percents of piezoelectric material are used in the sacrificial base and pillar array. A first volume percent in the base is lower than the second volume percent in the pillar array. In this way, the sacrificial base can be easily removed from the pillar array after the base and pillar array are sintered in the manufacture of a final composite piezoelectric transducer. A method of manufacturing a composite piezoelectric transducer from a sacrificial base and pillar array and a composite piezoelectric transducer made by the method are provided. A composite piezoelectric transducer stack is provided.
