Ultrasonic contact transducer for point-focussing surface waves

A single beam ultrasonic contact transducer for generating point-focussing and receiving surface acoustic waves having a narrow beam width and a high sound intensity at a focal point along a flat surface of a specimen, said transducer comprising:

• a curved piezoelectric element 17 for generating ultrasonic waves and having a concave bottom surface 18 and a convex top surface 18A;
• an acoustic contact lens including a top surface 9 and an exposed flat bottom surface 15 with said lens top surface and said lens flat bottom surface converging to form an arced bottom edge 16;
• said acoustic contact lens further including a convex front surface 14 opposite said arced bottom edge to contiguously receive said concave bottom surface 18 of said curved piezoelectric element 17 to enable, in use, said ultrasonic waves generated by said curved piezoelectric element 17 to be focussed at a flat surface of the specimen to enable detection, sizing and imaging of surface cracks and subsurface flaws of the specimen and to detect delamination in a laminated film specimen;
• and
• a scattering means integrally formed on said top surface of said acoustic contact lens for scattering said ultrasonic waves reflected from said flat bottom surface of said acoustic contact lens.

A double beam ultrasonic contact transducer for generating, point-focussing and receiving surface acoustic waves having a narrow beam width and a high sound intensity at a focal point along a flat surface of a specimen, said transducer comprising:

• a first and a second curved piezoelectric element with each element having a concave bottom surface and a convex top surface;
• a first and a second acoustic contact lens with each acoustic contact lens including a top surface 9 and an exposed flat bottom surface 15 with said lens top surface and said lens exposed flat bottom surface converging to form an arced bottom edge 16;
• each said acoustic contact lens further including a convex front surface 14 opposite said arced bottom edge to contiguously receive said concave bottom surface 18 of said curved piezoelectric element 17 to enable, in use, said ultrasonic waves generated by said curved piezoelectric element 17 to be focussed at a flat surface of the specimen, respectively;
• and
• a damper means positioned between said first acoustic contact lens and said second acoustic contact lens for absorbing ultrasound waves thereby preventing ultrasound present in one of said first and second acoustic contact lens from interfering with the remaining said acoustic contact lens to enable the detection, sizing and imaging of surface cracks and subsurface flaws of the specimen and to detect delamination of the laminated film specimen.

A double beam ultrasonic contact transducer for generating, point-focussing and receiving surface acoustic waves having a narrow beam width and a high sound intensity at a focal point along a flat surface of a specimen, said transducer comprising:

• a first and a second curved piezoelectric element with each element having a convex top surface and a concave bottom surface;
• a first and a second acoustic contact lens with each acoustic contact lens including a top surface 9 and an exposed flat bottom surface 15 with said lens top surface and said lens exposed flat bottom surface converging to form an arced bottom edge 16;
• each said acoustic contact lens further including a convex front surface 14 opposite said arced bottom edge to contiguously receive said concave bottom surface 18 of said curved piezoelectric element 17 to enable, in use, said ultrasonic waves generated by said curved piezoelectric element 17 to be focussed at a flat surface of the specimen, respectively;
• scattering means formed on said top surface of each said acoustic contact lens for scattering said ultrasonic waves reflected from said flat bottom surface of each said acoustic contact lens;
• and
• a damper means positioned between said first acoustic contact lens and said second acoustic contact lens for absorbing ultrasound waves thereby preventing ultrasound present in one of said first and second acoustic contact lens to enable the detection, sizing and imaging of surface cracks and subsurface flaws of the specimen and to detect delamination in the laminated film specimen.