Ultrasonic phased array transducer with an ultralow impedance backfill and a method for making

• Main Authors: SMITH LOWELL SCOTT, LORRAINE PETER WILLIAM
• Format: Patent
• Language: English
• Published: 25.10.2001
• Edition: 7
• Subjects: ACOUSTICS; ACOUSTICS NOT OTHERWISE PROVIDED FOR; FOR PERFORMING MECHANICAL WORK IN GENERAL; GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL; METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICALVIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING,NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; MUSICAL INSTRUMENTS; PERFORMING OPERATIONS; PHYSICS; SOUND-PRODUCING DEVICES; TRANSPORTING

The present invention discloses an ultrasonic phased array transducer with an ultralow backfill and a method for making. The ultrasonic phased array includes a low density backfill material having an ultralow acoustic impedance. The backfill material is either an aerogel, a carbon aerogel, an xerogel, or a carbon xerogel. A piezoelectric ceramic material and two matching layers are bonded to the backfill material. In one embodiment, a plurality of interconnect vias are formed in the backfill material with conducting material deposited in the vias. A portion of the bonded matching layers, the piezoelectric ceramic material, and the backfill material have isolation cuts therethrough to form an array of electrically and acoustically isolated individual elements. In a second embodiment, the backfill material is bonded to an electronic layer at a face opposite to the piezoelectric ceramic material and the matching layers. Then isolation cuts are made through the matching layers, the piezoelectric ceramic material, and the backfill material, to form an array of electrically and acoustically isolated individual elements.