Accession Number : ADD015797

Title :   Piezoelectric Ceramic Hydrostatic Sound Sensor.

Descriptive Note : Patent, filed 5 Dec 90, patented 2 Mar 93,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Kahn, Manfred ; Chase, Mark

Report Date : 02 Mar 1993

Pagination or Media Count : 6

Abstract : A piezoelectric ceramic hydrostatic sound sensor or transducer having high sensitivity to hydrostatic pressure is made by placing a flat plastic disc between two flat layers of green ceramic material, compressing and fusing the layers, heating to a first temperature at which the plastic decomposes, leaving a flat void in the ceramic, and heating to a second temperature at which the ceramic sinters. The transducer is provided with electrodes on its top and bottom surfaces. In a further improvement, ceramic particles are provided which are entrapped in the void; they render the sound sensor sensitive to inertial forces. In yet another improvement, the inside walls of the void are coated with a conductive noble metal connected to a terminal wire, whereby an additional electrode is provided for sensing the electromechanical response of the transducer.

Descriptors :   *CERAMIC MATERIALS, *HYDROSTATICS, *PIEZOELECTRIC MATERIALS, *DETECTORS, *SOUND, ELECTRODES, HEATING, HIGH SENSITIVITY, HYDROSTATIC PRESSURE, LAYERS, DISKS, COMPRESSION, SINTERING, INERTIAL SYSTEMS, METAL COATINGS, CONDUCTIVITY, ELECTROMECHANICAL DEVICES, ACOUSTICS, MATERIALS, PARTICLES, PLASTICS, RESPONSE, SURFACES, TEMPERATURE, TERMINALS, TRANSDUCERS, VOIDS, WALLS, WIRE

Subject Categories : Acoustics
      Fluid Mechanics
      Electricity and Magnetism
      Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE