Piezoelectric transducer and components therefor

Abstract

A piezoelectric transducer comprising a casing having an opening in one face and a piezoelectric element extending across the opening has a casing containing a backing material in direct contact with the piezoelectric element. The backing material comprises a polymeric composition which may contain a heavy metal oxide, e.g. BiO, or a metal, e.g. Ni, in particulate form, and/or may contain particles of a material of lower specific gravity than the surrounding composition, the distribution of said particles being such that they are most concentrated in a region remote from the piezoelectric element and are least concentrated or essentially absent in the region immediately adjacent the piezoelectric element.

Dependencies are inferred from the claim text.