Ultrasonic measurements of surface defects on flexible circuits using high-frequency focused polymer transducers
High frequency transducers made from a layer-by-layer deposition method are investigated as transducers for ultrasonic imaging. Prototypes of adhesive-free transducers with four active elements were made on a high performance PEI (Polyetherimide) substrate with precision milled spherical cavities used to produce focused ultrasonic beams. The transducer prototypes were characterized using a pulse - echo experimental setup in water tank using glass plate as a reflector. Then, it was used in a 3D ultrasonic scanning tank, to produce high - resolution ultrasonic images of flexible electronic circuits with the aim to detect defects in the outermost cover layer.
Accepted manuscript version. Published version available in Japanese Journal of Applied Physics 2017, 56(07JC05)