Method for making integrated matching layer for ultrasonic transducers

1999 ◽  
Vol 105 (1) ◽  
pp. 20
Author(s):  
J. Fleming Dias
Keyword(s):  
Ultrasonic Transducers ◽  
Matching Layer

scholarly journals Ultrasonic Transceiver with a Regular/Periodic 1-3 Piezocomposite Based on the SAW Resonance Mode on Damping Backing

Acoustics ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 110-127
Author(s):  
Alex Mezheritsky
Keyword(s):  
Sound Pressure ◽  
Vibrational Mode ◽  
Tungsten Powder ◽  
Resonance Effect ◽  
Ultrasonic Transducers ◽  
Practical Applications ◽  
Piezoelectric Resonance ◽  
Matching Layer ◽  
Transducer Design ◽  
Pulse Echo

A novel effective vibrational mode was discovered in the conventional transducer with an array of orthogonal (square) regular piezoelectric rods in 1-3 piezocomposite, containing the damping backing and front matching layers. The operational resonance in the structure was determined as the Surface Acoustic Wave (SAW) on the backing boundary excited by the adjacent piezo-rods, with its frequency typically near 3 times lower the fundamental half-lambda conventional piezocomposite resonance. Pulse-echo sensitivity and transmitting sound pressure level (SPL) in air showed that the signal strength is roughly comparable to the industrial similar air transducers at the frequency range 100–700 kHz, where at these frequencies the lateral and longitudinal piezoelement dimensions in the conventional transducer design are typically close to each other causing interference with unwanted coupling modes. As was determined theoretically and proved in experiments, the backing SAW resonance effect in the transducer performance is inherent just to the regular periodic 1-3 piezocomposite structure and does occur neither with randomly located/oriented piezo-rods nor in the homogeneous piezo-plate at least with the same lateral cross-section as the connected to it backing. The purpose of the article is to investigate a newly discovered operational vibrational mode of a SAW type in 1-3 regular piezocomposite, other than piezoelectric resonance. The investigated phenomena can improve the transceiver sensitivity and bandwidth, providing lower drive voltage and smaller and lighter weight ultrasonic transducers. Based on the piezocomposites with thickness’ 1–1.5 mm (rod resonance near 2–3 MHz), pillar width 0.2–0.8 mm, kerf width 0.1–0.4 mm, the transceivers with an operating frequency from 140 kHz to 650 kHz were designed and fabricated with a conventional backing of a mixture of high-density tungsten powder and epoxy and a matching layer of a mixture of low-density glass bubbles and epoxy. Experimental evaluation of their acoustical performance showed expected characteristics suitable for practical applications.

scholarly journals Modeling and Experimental Characterization of Bonding Delaminations in Single-Element Ultrasonic Transducer

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2269
Author(s):  
Wenxiang Ding ◽  
Maxime Bavencoffe ◽  
Marc Lethiecq
Keyword(s):  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Single Element ◽  
Experimental Characterization ◽  
The Finite Element Method ◽  
Matching Layer ◽  
Different Types ◽  
3D Printed ◽  
Piezoelectric Disk

Ultrasonic transducers performance can be seriously deteriorated by loss of adhesion between some constitutive elements such as the active element, the backing, or the matching layer. In the present work, the influence of bonding delaminations on the performance of a single-element ultrasonic transducer, which is composed of a piezoelectric disk, a backing, and a matching layer, is studied numerically and experimentally. Based on the positions between layers, two cases, i.e., delaminations between ceramic and backing or between ceramic and matching layer, are considered. Each case involves three different types of delaminations, which are marked as delamination type (DT)-I, II, and III. DT-I, a circular shape delamination, starts from the center and expands towards the peripheric zone; DT-II, an annular shape delamination, starts from the peripheric zone and expands towards the center; DT-III is a sector shape delamination with a given angle. The numerical simulations are performed by the finite element method and the influence of delaminations on the electromechanical admittance (EMA) of the transducer is investigated. 3D printed backings and matching layers are mounted on a PZT sample to assemble delaminated single-element transducers. An impedance analyzer is used for experimental measurements. Comparison between numerical and experimental results shows a reasonable agreement making changes in EMA an interesting indicator to inform about the occurrence and severity of delaminations in a single-element ultrasonic transducer.

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