Ultrasonic contact transducer for point-focussing surface waves
 An ultrasonic contact transducer for point-focussing surface waves having a narrow beam width and a high sound intensity at a focal point in order to obtain better resolution and high beam intensity, which is applicable to the nondestructive testing technique of the surface or subsurface of a specimen to be tested, is disclosed. The ultrasonic contract transducer generates surface waves, focuses the waves at one point on the surface of the specimen and receives again the signals scattered from the surface flaws or subsurface flaws of the specimen, in order to detect the surface cracks, surface flaws, subsurface flaws of the specimen and to detect the delamination in a thin laminated film. The ultrasonic contact transducer comprises a curved piezoelectric element for generating ultrasonic waves, a acoustic contact lens to enable, in use, the ultrasonic waves generated by the curved piezoelectric element to be focussed at a flat surface of the specimen to enable the detection, sizing and imaging of surface cracks and subsurface detects of the specimen and to detect delamination in the laminated film specimen. The acoustic contact lens further includes a scattering means integrally formed to the acoustic contact lens to scatter the ultrasonic waves reflected from the flat bottom surface of the acoustic contact lens. 
Korea Standards Research Institute
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G01N G01N G01N G10K G01N
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Byoung G. Jae O. Se K.
Kim Lee Lee