Acoustic Matching Layer Films Using B-Stage Thermosetting Polymer Resins for Ultrasound Transducer Applications

Acoustic matching layer films (MLFs) were fabricated using B-stage thermosetting polymer resins with various volume fractions of alumina and tungsten powders. After making certain thickness MLFs, ultrasonic matching layers were fabricated using a simple molding process. The thickness of the matching layers can be precisely adjusted from several micrometer to hundreds of micrometer, without any grinding process. Experimental values of acoustic impedances of the matching layers were in good agreement with theoretical values calculated by the Devaney model. Using the optimized acoustic matching layer by the MLFs, the maximum intensity and the fractional bandwidth of the ultrasonic transducer were increased by 10% and 37% respectively. The effectiveness of the matching layer using MLFs was successfully verified.