Pressure resistant piezoelectric acoustic sensor

US6262517A · kind A · utility

Assignee

• Materials Systems, Inc. · US

Inventors

• Gerald SCHMIDT · Frankfurt am Main, DE
• Leslie J. Bowen · Concord, US

Key dates

• Filing date: Feb 11, 2000
• Grant date: Jul 17, 2001
• Expiry date: Feb 11, 2020

Classification

• Technology area (CPC G): Physics
• CPC primary: G01H11/08
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

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 p…