Evaluation of the acoustical properties of adhesive-free dual layer piezoelectric PVDF copolymer transducer

Abstract

Dual layer piezoelectric transducer has been developed using an adhesive free process and characterized both experimentally and by FEM models. Our findings show an enhanced amplitude when both layers are used as a transceiver system for sufficiently large pulse width. The peak frequency obtained from Comsol modeling shows a good agreement with the experimental results.

Chirp coded ultrasonic pulses used for scanning acoustic microscopy

“…1 as a two-dimensional side view. The combined substrate and lens material PEI was chosen due to its very good thermal stability, good impedance match to P(VDF-TrFE) and very low acoustic attenuation [17]. As illustrated in Fig.…”

“…water, polymers, and human tissue) and high chemical stability make these materials suitable for ultrasonic applications, especially in the high frequency end (20 MHz-1 GHz). The flexible film of PVDF and its copolymer fabricated by techniques such as spin coating, hot pressing, stamping and spraying on flat substrate [12][13][14][15][16][17][18].…”

High frequency copolymer ultrasonic transducer array of size-effective elements

“…Our aim has been to build prototypes of dual-layer copolymer transducers on a constrained substrate area containing a number of active elements, and to explore a solution for an efficiently electricsignal connection. Unlike previous works where electrode connection lines are typically brought out horizontally to the edge of the array (see for example [17]), and with adopted concept from electronic 3D integration, we have implemented a method for producing via connectors allowing individual element connection directly from the backside of the transducer. This method will typically produce a shorter and more uniform signal path lengths for the transducer elements, which again will have benefits in terms of delay times and parasitic capacitance, resistance and inductance [18].…”

“…The proposed connection method is realized from well-established etching and deposition methods, which potentially can be scaled-up to a large number of elements. For our dual-layer transducer prototypes, it has also been a goal to avoid adhesives in the assemble process to obtain benefits with respect to sensitivity [17,[19][20][21]. A number of tests were also done on the prototypes, including, pulser-receiver characterization, probe scanning of emitted sound fields, and imaging tests.…”

Numerical and Experimental Evaluation of High-Frequency Unfocused Polymer Transducer Arrays

“…At the same time, these piezoelectric polymers are very suitable materials for achieving high frequencies with a large bandwidth for ultrasonic sensors and transducers [ 18 , 19 , 20 , 21 , 22 , 23 ]. The flexible piezoelectric film of PVDF and its copolymer are fabricated by techniques such as spin coating, hot pressing, stamping, and spraying on a flat substrate [ 11 , 24 , 25 , 26 , 27 , 28 , 29 ]. Polymer-based transducers also typically provide a much better acoustic match with commonly used materials like water, human tissue, and polymers than transducers made from inorganic piezoelectric materials [ 24 , 25 ].…”