Patent ID: 7719926
Filing Date: 2010-05-18
Classification: H04R

Abstract:
1. A slotted cylinder acoustic transducer, comprising: a cylindrical housing shell having an inner surface, an outer surface, a central major axis of curvature, a thickness between the inner surface and the outer surface, the thickness in a direction perpendicular to the central major axis of curvature, and a slot through the cylindrical housing shell extending in a direction parallel to the central major axis of curvature and forming a gap in the cylindrical housing shell; a crescent-shaped insert having an inner surface, an outer surface, a central major axis of curvature parallel to the central major axis of curvature of the cylindrical housing shell, and a tapered thickness between the inner surface and the outer surface, the thickness in a direction perpendicular to the central major axis of curvature, wherein a shape of the outer surface of the crescent-shaped insert matches a shape of the inner surface of the cylindrical housing shell, wherein the outer surface of the crescent-shaped insert is disposed proximate to the inner surface of the cylindrical housing shell, wherein the thickness of the crescent-shaped insert is greatest at a position opposite the slot; a plurality of piezoelectric ceramic elements, each having a respective solid shape, and each having a respective central major axis parallel to the central major axis of curvature of the cylindrical housing shell; and a plurality of electrodes, each having a planar shape, wherein the plurality of piezoelectric ceramic elements and the plurality of electrodes are interposed in a ceramic stack assembly, an electrode between each two adjacent piezoelectric ceramic elements, the ceramic stack assembly having an inner surface, an outer surface, a central major axis of curvature parallel to the central major axis of curvature of the cylindrical housing shell, and a thickness between the inner surface and the outer surface, the thickness in a direction perpendicular to the central major axis of curvature, wherein a shape of the outer surface of the ceramic stack assembly matches a shape of the inner surface of the crescent-shaped insert, wherein the outer surface of the ceramic stack assembly is disposed proximate to the inner surface of the crescent-shaped insert, wherein each one of the plurality of piezoelectric ceramic elements has the same solid size and shape, and wherein each one of the electrodes has the same planar shape, wherein the ceramic stack assembly has a constant thickness between the inner surface and the outer surface of the ceramic stack assembly, wherein a material of the crescent-shaped insert is selected to have a density and a modulus of elasticity about the same as a density and a modulus of elasticity of a material of the plurality of piezoelectric ceramic elements.