Us20120226201a1 us508,709 us2010508709a us2012226201a1 us 20120226201 a1 us20120226201 a1 us 20120226201a1 us 2010508709 a us2010508709 a us 2010508709a us 2012226201 a1 us2012226201 a1 us 2012226201a1 authority us united states prior art keywords curved matching layer transducer hifu transducer surface prior art date 20091109 legal status the. Oct 05, 2010 a matching layer capable of use in a high frequency ultrasonic transducer stack having a plurality of layers, the matching layer comprising a cured matrix material loaded with a plurality of first heavy particles and a plurality of second light particles, wherein the first heavy particles contribute significantly to the acoustic impedance of. Design and manufacture of an ultrasonic transducer for long. Matching layer piezo ceramic disc backing layer catheter physical design 7f 3f 1mm figure 2. Aluminaepoxy nanocomposite matching layers for high. Characterization of ultrathin quarterwavelength matching. Industrial ultrasonic materials transducers acoustic matching layer convex type probe backing layer acoustic lens. Once materials that constitute the two matching layers are selected, only their thicknesses have to be calculated.
Harris school of electronics and computer science, university of southampton, university road, so17 1bj southampton, uk abstract this work describes a new approach to impedance matching for ultrasonic transducers. As the characteristic impedance of the pzt z p 33 mrayl is greater than that of water z 0 1. Design of matching layers for highfrequency ultrasonic transducers article pdf available in applied physics letters 10712. How to select and mount transducers in ultrasonic sensing. To test the effectiveness of the matching layer, a 42 mhz singlecrystal lithium niobate transducer with a nano matching layer was fabricated, and properties were tested and compared. Ultrasoundultrasonic transducer, system and application. The transducer is mainly composed of piezoelectric pzt element, backing material, matching layer and housing, as shown in figure 1a. Ca2644224a1 ultrasonic matching layer and transducer. Transducer waveform and spectrum transducer waveform and spectrum analysis is done according to test conditions and definitions of astm e1065.
Materials, based on blends of digylcidyl ether of bisphenol a and 1,4cyclohexanedimethanol diglycidyl ether, are described. Design and manufacture of an ultrasonic transducer for. Materials, based on blends of diglycidyl ether of bisphenol a and 1,4cyclohexanedimethanol diglycidyl ether, are described. With stateoftheart manufacturing capabilities and an experienced engineering team, we are able to provide your company with an ultrasonic transducer ideally suited for your application. Characteristics of alepoxy composite as backing material in. Influence of backing and matching layers in ultrasound. Without proper matching layers, large acoustic impedance mismatch between piezoelectric resonator and the human body tissue will cause most of the ultrasound energy to be reflected at the interface. In this study, we designed and fabricated acoustic matching layer optimized for leadfree ultrasonic. Poco, with its family of ultrasound materials, is providing a material advantage to manufacturers and operators of ultrasound transducers. This paper describes the acoustic properties of a range of epoxy resins prepared by photocuring that are suitable for application in piezoelectric ultrasonic transducer matching layers. In one aspect, matching layers for an ultrasonic transducer stack having a matching layer comprising a matrix material loaded with a plurality of micronsized and nanosized particles. A spincoating process was used to fabricate aluminapolymer nanocomposite films with alumina volume fractions ranging from 14 to 32%.
A reflective layer structure is inserted between the transducer and. For the same transducer design specification described above, a three layer matching at the. The optimum matching layer would have a tapered impedance between 1. Matching layers are used to make the acoustic impedance between the body and the piezoelectric crystal as little as possible.
Theory in general, thickness of the piezoelectric material in a conventional ultrasonic transducer is a half wavelength, while the suggested transducer has a quarter. Multiple acoustical matching layer design of ultrasonic transducer for medical application. Modelling of a novel highimpedance matching layer for high. Design of ultrasonic transducers with multiple acoustic. In another aspect, the matrix material is loaded with a plurality of heavy and light particles. The matching layers were made of a 03 composite material consisted of ceramics particles and epoxy resin for controlling its acoustic impedance. A sphericallyshaped pzt thin film ultrasonic transducer. None of the bonding agents resulted in acceptable bonding in the case of gallium phosphate piezoelement. The transducer is a very important part of the ultrasonic instrumentation system. Furthermore, in order to vary the elastic character of the base resin, samples. Analysis of broadband piezoelectric transducers by.
Optimization of matching layer design for medical ultrasonic. Ultrasound physics ch 8 transducers flashcards quizlet. Design of matching layers for highfrequency ultrasonic. Matching layers are crucial components in ultrasonic transducers for medical imaging. With more than forty years of transducer experience, olympus ndt has developed a wide range of custom transducers for special applications in flaw detection, weld inspection, thickness. This paper presents the microfabrication of an acoustic impedance gradient matching layer on a sphericallyshaped piezoelectric ultrasonic transducer. We use mason equivalent circuit to calculate the frequency band, the wave form and the sensitiyity of. Us20120226201a1 curved ultrasonic hifu transducer with pre. If the transducer is mounted on the bottom of the tank on the outer wall, the bare transducer type can be utilized. The ultrasonic transducer of claim 1, wherein the front metal layer at least partially surrounds of the piezoelectric element and the acoustic matching layer. Design and fabrication of acoustic matching layer for lead. Sensitivity and directivity measurement of ultrasonic transducer with polymerpowder matching layer. Sep 21, 2015 in the pulseecho experiment, the transducer echo amplitude increased by 84. And the acoustic performance improvement of the transducer was verified by simulation.
Also included in this paper are a theoretical analysis of the device design and a micromachining technique to produce the novel. How to select and mount transducers in ultrasonic sensing for level sensing and fluid id 1. Multiple acoustical matching layer design of ultrasonic. A higher frequency generates an ultrasound beam with energy that is more confined, and attenuates faster. The impedance values of the matching layer calculated from different formulas are very different. As discussed on the previous page, the transducer incorporates a piezoelectric element, which converts electrical signals into mechanical vibrations transmit mode and mechanical vibrations into electrical signals receive mode. Liquid on the transducers active surface temporarily degrades performance by detuning the matching layer. New design of matching layers for high power and wide band. The results of an experimental study of the sensitivity and directivity pattern of the. When the sensor is operating, water on the transducer face is typically vaporized. Matching ultrasonic transducer using two matching layers. Us20120226201a1 us508,709 us2010508709a us2012226201a1 us 20120226201 a1 us20120226201 a1 us 20120226201a1 us 2010508709 a us2010508709 a us 2010508709a us 2012226201 a1 us2012226201 a1 us 2012226201a1 authority us united states prior art keywords curved matching layer transducer hifu transducer surface prior art date 20091109 legal status the legal status is an assumption and is. Multiple matching layers can be used for multiple frequencies.
In another aspect, an ultrasound transducer stack comprises a piezoelectric layer and at least one matching layer. The particle size of alumina is in the range of 10 to 40 nm. Influence of backing and matching layers in ultrasound transducers performance valeria m. In the pulseecho experiment, the transducer echo amplitude increased by 84.
New type of matching layer for aircoupled ultrasonic. Us8847467b2 high frequency ultrasonic transducer and. Quarter wave matching layer fall 2019 12 if z m z st z t and thickness of matching layer. At high frequencies 5omhz, the hi4 matching layers become extremely thin and the characterization of its properties becomes very challenging. Us20120226201a1 curved ultrasonic hifu transducer with. Application fields of ultrasonic transducers can be divided into two categories, a high resolution required field and a high power required field. Information about the openaccess article a sphericallyshaped pzt thin film ultrasonic transducer with an acoustic impedance gradient matching layer based on a micromachined periodically structured flexible substrate in doaj.
For imaging, it means better resolution and reduced imaging depth. Basic principle of medical ultrasonic probes transducer the ultrasonic probe consists of a piezoelectric element, backing material, an acoustic matching layer and an acoustic lens. The performances wide fhwm and a good level of transmission of the proposed matched transducer are similar to those obtained with the ideal one quarterwave layer matching. The transducer is mainly composed of piezoelectric pzt element, backing material, matching layer.
Request pdf optimization of matching layer design for medical ultrasonic transducer this thesis work contains two major parts. In the medical ultrasonic test and ndt,it is often to use matching layer to improvewave shape and sensitivity of the transducer. To validate the model, experimental measurements are conducted on an inhome constructed piezoelectric transducer. A sphericallyshaped pzt thin film ultrasonic transducer with. In the first part, ultrasonic wave propagation in multilayer. Introduction an ultrasonic transducer has been widely used for a decade as flaw detectors and distance measuring devices. The center frequency of an ultrasound transducer is determined by the application. Panametricsndt ultrasonic transducers are available in more than 5000 variations in frequency, element diameter, and connector styles. The following describes the components and their functions of the convex type probe as an example. Air and crystal have very different acoustic impedances.
Tapered acoustic matching layers stanford university. Pdf matching ultrasonic transducer using two matching. Ieee transactions on ultrasonics, ferroelectrics, and frequency control volume. A matching layer capable of use in a high frequency ultrasonic transducer stack having a plurality of layers, the matching layer comprising a cured matrix material loaded with a plurality of first heavy particles and a plurality of second light particles, wherein the first heavy particles contribute significantly to the acoustic impedance of. One of the main tasks of this thesis is to investigate matching layer design with gradient acoustic impedance to achieve much broader bandwidth 100%. To test the effectiveness of the matching layer, a 42 mhz singlecrystal lithium niobate transducer with a nanomatching layer was fabricated, and properties were tested and compared. Pdf design of matching layers for highfrequency ultrasonic. Mullholland3 1 department of pure and applied chemistry, thomas graham building, university of strathclyde, 295 cathedral street, glasgow g1 1xl. The approach we have used consists of impedance matching the front face of the piezoelectric transducer to the propagating medium with a quarter wavelength impedance matching layer and inserting an unmatching quarter wavelength acoustical layer between the rear face and backing material. A quarterwavelength vibration mode transducer using clamped. Ultrasonic matching layer and transducer visualsonics inc. Modelling of a novel highimpedance matching layer for. Near surface resolution is the ability of the ultrasonic system to detect reflectors located close to the surface of the test piece.
This papers aim is to determine optimal properties of the matching layers of the transducer for each of the applications. A curved high intensity focused ultrasound hifu transducer comprising a curved piezoelectric array having opposite convex and concave surfaces, the concave surface being a transmitting surface, and a plurality of acoustic transmission areas, a plurality of electrodes located on the surfaces of the curved piezoelectric array for applying electrical transmit signals to the acoustic. Because of the impedance mismatch between pzt and water 35 and 1. Therefore, no ultrasound will be transmitted beyond the ultrasonic transducers surface.
However, if the transducer is mounted on the top in the inner. Acoustic impedance matching of piezoelectric transducers to the air. Finite element modeling of an ultrasonic transducer. Kazan volga region federal university, 18 kremlyovskaya str. In order to match the piezoelectric transducer to a water load, matching layers must be used. This paper presents a new concept in the design of an impedance matching structure for air coupled ultrasonic transducers. The use of multiple matching layers based on the same principle, can further improve transducer performance especially to produce highefficiency, wideband piezoelectric transducers. A quarterwavelength vibration mode transducer using. Acoustical matching layer the acoustical matching layer is used to increase the efficiency in the acoustic energy. Wide bandwidth and sensitive ultrasonic transducers are needed in numerous medical and nondestructive applications. Improved acoustic coupling of aircoupled micromachined ultrasonic transducers stefon shelton1, ofer rozen1, andre guedes1, richard przybyla2, bernhard boser2, david a.
Characteristics of alepoxy composite as backing material. With more than forty years of transducer experience, olympus ndt has developed a wide range of custom transducers for special. The ultrasonic transducer of claim 9, wherein the front metal layer forms at least a portion of a housing containing the piezoelectric element and the acoustic matching layer. Also included in this paper are a theoretical analysis of the device design and a micromachining technique to produce the novel transducer. Harris school of electronics and computer science, university of southampton, university road, so17 1bj. The acoustic matching layer can be designed to achieve higher acoustic energy transmission and operating bandwidth.
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