Patent ID: 8063540

Claim:
An ultrasound transducer or transducer array for transmission and reception of bulk ultrasound waves in an acoustic load material through a front face, with a back face on the opposite side, comprising an active transducer material including a ferro-electric ceramic film with front and back faces, a back electrode on said back face of said ferro-electric ceramic film, a film layer on said front face of said ferro-electric ceramic film, said film layer including at least a front electrode, and a substrate, said film layer being disposed between said ceramic film and said substrate, wherein said film layer between said ceramic film and said substrate is so dense that diffusion from said substrate to said ceramic film during the manufacturing process is adequately blocked to avoid contamination of said ceramic film by the substrate material, wherein a thickness of said film layer between said ceramic film and said substrate is less than λ/10, where λ is the wave length for the bulk ultrasound waves transmitted and received in a thickness direction of said film layer at the highest operation frequencies of the transducer or transducer array, and the thickness of said substrate is modified at least in front of said ceramic film through one of etching and grinding techniques, so that said modified substrate becomes part of a layered load impedance matching structure between said ceramic film front face and said load material.