EP0173864A1 - Transducteur à ultrasons muni d'une couche d'adaptation poreuse - Google Patents

Transducteur à ultrasons muni d'une couche d'adaptation poreuse Download PDF

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Publication number
EP0173864A1
EP0173864A1 EP85109705A EP85109705A EP0173864A1 EP 0173864 A1 EP0173864 A1 EP 0173864A1 EP 85109705 A EP85109705 A EP 85109705A EP 85109705 A EP85109705 A EP 85109705A EP 0173864 A1 EP0173864 A1 EP 0173864A1
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EP
European Patent Office
Prior art keywords
adaptation layer
layer
ultrasonic transducer
acoustic impedance
adaptation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP85109705A
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German (de)
English (en)
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EP0173864B1 (fr
Inventor
Hans Dr. Kaarmann
Karl Dr. Lubitz
Jutta Mohaupt
Martina Vogt
Wolfram Wersing
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Siemens AG
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Siemens AG
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Application filed by Siemens AG filed Critical Siemens AG
Priority to AT85109705T priority Critical patent/ATE45054T1/de
Publication of EP0173864A1 publication Critical patent/EP0173864A1/fr
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Publication of EP0173864B1 publication Critical patent/EP0173864B1/fr
Expired legal-status Critical Current

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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/02—Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators

Definitions

  • the invention relates to an ultrasonic transducer with a piezoelectric transducer, with a first adaptation layer, which adjoins the piezoelectric transducer, and with a second adaptation layer, which is applied to the first adaptation layer and faces an object to be examined in ultrasonic operation.
  • Ultrasonic transducers of the type mentioned are widely used in medical technology in order to obtain information about the internal structures of tissues and organs in a patient.
  • One difficulty here is in coupling the ultrasound waves into the patient.
  • the piezoelectric transducer of medical ultrasound antennas often comprises a material that has a relatively high acoustic impedance.
  • Materials such as ceramics made of lead zirconate titanate, for example, have an acoustic impedance of approx. 30 x 10 6 kg / m 2 s.
  • the skin and tissue of the patient however, has only an acoustic resistance of about 1.5 x 10 6 kg / m 2 s.
  • an adaptation layer is arranged between the transducer and the tissue.
  • a single matching layer has been made from one to transform or adapt the acoustic impedance of the ceramic transducer in or to that of the object to be examined (e.g. human tissue with an impedance of approximately 1.5 x 10 kg / m 2 s) Plastic with a acoustic impedance of approx. 3 x 10 6 kg / m 2 s or a little more.
  • This adaptation layer had a thickness of ⁇ / 4. ⁇ is the wavelength that is present in the material according to the nominal frequency of the ultrasonic transducer.
  • a theoretically favorable value is 7 x 10 6 k g / m 2 s when going from 30 x 10 6 kg / m 2 s (ceramic) to 1, 5 x 1 0 6 kg / m 2 s stepped down.
  • This type of adaptation with a single adaptation layer has the disadvantage that it is not sufficiently broadband. For this reason, in order to achieve high penetration depths and good axial resolution over a large frequency range, a first and a second adaptation layer, each with ⁇ / 4 thickness, have been adopted (cf. Biomedical Technology, Volume 27, Issue 7-8, 1982, p . 182-185).
  • the acoustic impedances of these two adaptation layers are approximately 12 ⁇ 10 6 kg / m's for the first adaptation layer facing the piezoelectric ultrasound transducer and approximately 4.2 ⁇ 10 6 kg / m 2 s for the adaptation layer facing the tissue or patient. In this way, a much better adaptation can be achieved.
  • the second matching layer with an acoustic impedance of approximately 4.2 x 10 kg / m's can be easily found or manufactured. Common plastics can be used for this: Since the acoustic impedance of the second (plastic) matching layer, which can be advantageously used, depends only slightly on the impedance of the ultrasound transducer ceramic, the impedance once selected is equally suitable for all PZT ceramics of the ultrasound transducer.
  • the first adaptation layer has a decisive influence on the quality of the ultrasound image.
  • the object of the invention is therefore to provide a first adaptation layer for an ultrasound transducer of the type mentioned at the outset, which is related to its manufacture acoustic impedance is easily adjustable and its mechanical properties enable relatively easy processing.
  • the first matching layer consists of a porous piezoceramic material, the porosity of which is selected so that with a layer thickness of ⁇ / 4 there is a predetermined acoustic impedance with a value between that of the piezoelectric transducer and that of the second matching layer results, where ⁇ is the wavelength of the ultrasound in the first adaptation layer at nominal frequency.
  • the acoustic impedance of the ceramic material is dependent on its porosity, the acoustic impedance can be influenced in a simple manner during manufacture. Depending on whether the pore quantity and / or the pore size is specifically increased or decreased, there is a smaller or larger acoustic impedance.
  • a value in the critical range of approx. 12 x 10 6 kg / m 2 s can be set well by varying the porosity. It has proven to be advantageous to produce a whole series of, for example, 10 porous ceramic adaptation layers, which cover the area around 12 ⁇ 10 6 kg / m 2 s in fine gradations of, for example, 0.2 ⁇ 10 6 kg / m 2 s. All of these matching layers are given a layer thickness of X / 4 with regard to their acoustic impedance. Experiments can then be used to determine which of the 10 matching layers produced results in an optimal matching for the existing piezoelectric transducer.
  • the base material for the first adaptation layer is a ceramic material, it can be processed easily. It is easy to turn, mill, glue and grind.
  • a further advantageous embodiment of the invention results if the predetermined acoustic impedance of the first matching layer has a gradient which has a positive slope in the direction of the piezoelectric transducer.
  • This measure makes it possible for the first adaptation layer to have a continuous transition in acoustic impedance from approx. 30 x 10 6 kg / m 2 s down to approx. 4 x 10 6 kg / m 1 s, the value of the second adaptation layer, guaranteed.
  • the frequency response of the ultrasound transducer becomes even broader than it is due to the use of two adaptation layers.
  • FIG. 1 shows an ultrasound transducer 1, which comprises a total of four layers: a damping layer 3, a layer 5, in which a number of piezoelectric transducer elements 7 are embedded and which is referred to below as "piezoelectric transducer", a first adaptation layer 9 and a second adaptation layer 11
  • the piezoelectric transducer elements 7 emit pulsed acoustic waves 13 in the ultrasound range in the direction of the first and second adaptation layers 9 and 11, respectively.
  • the acoustic waves 13 should be coupled as freely as possible into an object to be examined, in this case a patient 15. Meet the.
  • Z l is the acoustic impedance of the first matching layer 9
  • Z 2 is the impedance of the second matching layer 11
  • Z K is that of the piezocelectric transducer 7
  • Z g is that of the tissue at the coupling point.
  • the first adaptation layer 9 lies in a range that is difficult to achieve with natural materials.
  • the first matching layer 9 comprises a material of comparatively high impedance, which is provided with cavities or pores 17 which change the acoustic behavior of the selected material, including reducing the impedance.
  • a porous ceramic is preferably selected as the material for the first adaptation layer 9. It can be processed well and easily.
  • the layer thickness of the adaptation layers 9 and 11 is ⁇ / 4 in each case. ⁇ is the wavelength of the ultrasound in the adaptation layers 9, 11. It corresponds to the frequency with which the piezoelectric transducers 7 are excited.
  • the acoustic impedance of the first matching layer 9 When manufacturing the ultrasound transducer 1, it is often not possible to state exactly from the start what value the acoustic impedance of the first matching layer 9 must have. This value depends, among other things, on the acoustic impedance Z K of the piezoelectric transducer elements 7 themselves, which has a certain spread, and also on the impedance of the second matching layer 11, which is preferably made of plastic and can also vary in value. It is therefore desirable to have a number of first matching layers 9 available whose acoustic impedances have a gradation. It can then be determined by experiments with the ultrasound transducer 1 which of these adaptation layers 9 is suitable for being permanently and finally installed in the ultrasound transducer 1 in question.
  • the first adaptation layer 9 is provided with uniformly distributed pores 17.
  • the pores 17 can be varied in their average density and / or their size during manufacture, as a result of which the acoustic impedance Z l specifically assumes different values. In this way, an assortment of finely graduated first adaptation layers 9 can be produced, from which the cheapest is then selected.
  • FIG. 2 shows a diagram in which the acoustic impedance of the first matching layer 9 is plotted against the pore fraction or the porosity (in%) in the first matching layer 9.
  • the first matching layer 9 here preferably consists of lead-zirconate-titanate ceramic. Another material with values in the desired impedance range can also be selected. 2, the desired acoustic impedance of approximately 12 ⁇ 10 6 kg / m 2 s is achieved at a porosity of approximately 36%. By varying this percentage in the range + 2%, the range of acoustic impedance z. B. can be varied between 11 and 13 x 10 6 kg / m 2 s. By small changes in the porosity, for example in the order of 1 % , a fine gradation of the acoustic impedance Z 1 of the first matching layer 9 can be achieved here. In principle, this also applies to other materials.
  • the frequency constants of the various complex ceramic systems in question differ little from each other.
  • a first adaptation layer 9 with the desired acoustic impedance of approx. 12 ⁇ 10 6 kg / m l s can therefore be produced for each ceramic mass transducer.
  • the complex ceramic systems mentioned above all have the further advantage that they have piezoelectric properties. This is of particular importance with regard to the thermal expansion of the first adaptation layer 9. This must namely be adapted to that of the piezoelectric transducer elements 7. If both the piezoelectric transducer elements 7 and the first adaptation layer 9 now consist of a piezoceramic material, their thermal expansion coefficients are so close together that the first adaptation layer 9, for example can be adjusted in their thermal expansion of the piezoelectric transducer elements 7 by adding dopants. This prevents mechanical stresses with crack formation or even breakage at the boundary layer.
  • FIG. 3 shows a first adaptation layer 9, in which the density of the pores 17 is distributed differently. There are more pores 17 towards the second adaptation layer 11 than towards the upper side, which connects to the piezoelectric transducer 5.
  • This different pore density ie the pore concentration and / or size decreasing upwards, also causes a different acoustic impedance, which decreases in the course of the first adaptation layer 9 from top to bottom (gradient).
  • the first matching layer 9 has an acoustic impedance Z K of approximately 30 ⁇ 10 kg / m l s on its upper side, that is to say the boundary layer with the piezoelectric transducer 7, and on its lower side , which points to the second matching layer 11, has an acoustic impedance of approx. 4 x 10 6 kg / m's. So it is possible to produce the first matching layer 9 so that its acoustic impedance Z 1 in the ceiling direction changes continuously between two desired values.
  • An adaptation layer 9 of this type with an impedance gradient results in a particularly broadband adaptation.
  • the porosity gradient can e.g. can be achieved in that the adaptation layer is produced in a film casting process. Bead polymer is added to the pouring slurry, which separates due to gravity. Different gradients can be set both by the viscosity of the casting slip for the film of the first adaptation layer 9 and by the course of the subsequent sintering.
  • first matching layers 9 with different impedance gradients and to subsequently decide by trial and error which of these first matching layers 9 is the most suitable for installation in the ultrasonic transducer 1.
  • This experimental finding of the suitable first adaptation layer 9 is appropriate because a large number of criteria must be taken into account, the mutual influences and interactions of which can only be determined in an experiment. So e.g. For each first adaptation layer 9, it should be checked how it affects the sensitivity of the ultrasound transmitter or receiver, the pulse shape of the transmission pulse, its pulse length, phase jumps, etc. In addition to these criteria, which influence the image quality, the thermal expansion coefficient and the layer thickness of the first adaptation layer 9, which can always only approximate> / 4, are also decisive.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Transducers For Ultrasonic Waves (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
  • Materials For Medical Uses (AREA)
EP85109705A 1984-08-16 1985-08-02 Transducteur à ultrasons muni d'une couche d'adaptation poreuse Expired EP0173864B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85109705T ATE45054T1 (de) 1984-08-16 1985-08-02 Poroese anpassungsschicht in einem ultraschallapplikator.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3430161 1984-08-16
DE19843430161 DE3430161A1 (de) 1984-08-16 1984-08-16 Poroese anpassungsschicht in einem ultraschallapplikator

Publications (2)

Publication Number Publication Date
EP0173864A1 true EP0173864A1 (fr) 1986-03-12
EP0173864B1 EP0173864B1 (fr) 1989-07-26

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Family Applications (1)

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EP85109705A Expired EP0173864B1 (fr) 1984-08-16 1985-08-02 Transducteur à ultrasons muni d'une couche d'adaptation poreuse

Country Status (5)

Country Link
US (1) US4686409A (fr)
EP (1) EP0173864B1 (fr)
JP (1) JPH0644837B2 (fr)
AT (1) ATE45054T1 (fr)
DE (2) DE3430161A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0171716A2 (fr) * 1984-08-16 1986-02-19 Siemens Aktiengesellschaft Procédé pour la fabrication d'une matière poreuse piézoélectrique et matière produite selon le procédé
EP0361757A2 (fr) * 1988-09-29 1990-04-04 British Gas plc Dispositif d'adaptation
EP0421286A2 (fr) * 1989-10-03 1991-04-10 Richard Wolf GmbH Transducteur piézoélectrique
EP0629992A2 (fr) * 1993-06-15 1994-12-21 Hewlett-Packard Company Microrainures pour l'apodisation et la focalisation des transducteurs cliniques ultrasonores à large bande
EP0707898A2 (fr) * 1994-10-21 1996-04-24 Hewlett-Packard Company Procédé pour former intégralement un transducteur et des couches d'adaptation d'impédance

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JPS61169099A (ja) * 1985-01-22 1986-07-30 Matsushita Electric Ind Co Ltd 超音波送受波器
US5119840A (en) * 1986-04-07 1992-06-09 Kaijo Kenki Co., Ltd. Ultrasonic oscillating device and ultrasonic washing apparatus using the same
DE8611844U1 (de) * 1986-04-30 1986-08-07 Siemens AG, 1000 Berlin und 8000 München Ultraschall-Applikator mit einer Anpassungsschicht
JPS6313497A (ja) * 1986-07-02 1988-01-20 Nec Corp 水中広帯域送受波器
JP2794720B2 (ja) * 1988-08-23 1998-09-10 松下電器産業株式会社 複合圧電振動子
JP2745147B2 (ja) * 1989-03-27 1998-04-28 三菱マテリアル 株式会社 圧電変換素子
US4928264A (en) * 1989-06-30 1990-05-22 The United States Of America As Represented By The Secretary Of The Navy Noise-suppressing hydrophones
US5275878A (en) * 1990-02-06 1994-01-04 Matsushita Electric Works, Ltd. Composite dielectric and printed-circuit use substrate utilizing the same
DE4117638A1 (de) * 1990-05-30 1991-12-05 Toshiba Kawasaki Kk Stosswellengenerator mit einem piezoelektrischen element
DE4028315A1 (de) * 1990-09-06 1992-03-12 Siemens Ag Ultraschallwandler fuer die laufzeitmessung von ultraschall-impulsen in einem gas
US5121628A (en) * 1990-10-09 1992-06-16 Merkl Arthur W Ultrasonic detection system
US5300852A (en) * 1991-10-04 1994-04-05 Honda Giken Kogyo Kabushiki Kaisha Piezoelectric ceramic laminate device
US5410205A (en) * 1993-02-11 1995-04-25 Hewlett-Packard Company Ultrasonic transducer having two or more resonance frequencies
JP3358851B2 (ja) * 1993-03-11 2002-12-24 本田技研工業株式会社 感湿性アクチュエータ
US5460181A (en) * 1994-10-06 1995-10-24 Hewlett Packard Co. Ultrasonic transducer for three dimensional imaging
US5434827A (en) * 1993-06-15 1995-07-18 Hewlett-Packard Company Matching layer for front acoustic impedance matching of clinical ultrasonic tranducers
JP3926448B2 (ja) * 1997-12-01 2007-06-06 株式会社日立メディコ 超音波探触子及びこれを用いた超音波診断装置
EP0979686A3 (fr) * 1998-08-12 2002-02-06 Ueda Japan Radio Co., Ltd. Feuille céramique piézoélectrique poreuse et tansducteur piézoélectrique
JP4223629B2 (ja) * 1999-06-16 2009-02-12 日本特殊陶業株式会社 超音波探触子用送受波素子及びその製造方法並びに該送受波素子を用いた超音波探触子
GB0019140D0 (en) * 2000-08-05 2000-09-27 Univ Strathclyde Ultrasonic transducers
ES2239500B1 (es) * 2003-03-07 2006-12-01 Consejo Sup. Investig. Cientificas Dispositivo para la caracterizacion de materiales por ultrasonidos con acoplamiento por gases (aire) y su aplicacion para llevar a cabo un test no destructivo para verificar la integridad de membranas porosas.
US7513147B2 (en) * 2003-07-03 2009-04-07 Pathfinder Energy Services, Inc. Piezocomposite transducer for a downhole measurement tool
US7075215B2 (en) * 2003-07-03 2006-07-11 Pathfinder Energy Services, Inc. Matching layer assembly for a downhole acoustic sensor
US20050039323A1 (en) * 2003-08-22 2005-02-24 Simens Medical Solutions Usa, Inc. Transducers with electically conductive matching layers and methods of manufacture
DE10344741A1 (de) * 2003-09-25 2005-04-14 Endress + Hauser Gmbh + Co. Kg Schall- oder Ultraschallwandler
DE102005063652B3 (de) 2005-06-09 2020-06-04 Tdk Electronics Ag Piezoelektrisches Vielschichtbauelement
JP2007288289A (ja) * 2006-04-13 2007-11-01 Honda Electronic Co Ltd 超音波振動子及び超音波洗浄機
US7587936B2 (en) * 2007-02-01 2009-09-15 Smith International Inc. Apparatus and method for determining drilling fluid acoustic properties
US8117907B2 (en) * 2008-12-19 2012-02-21 Pathfinder Energy Services, Inc. Caliper logging using circumferentially spaced and/or angled transducer elements
DE102008055123B3 (de) 2008-12-23 2010-07-22 Robert Bosch Gmbh Ultraschallwandler zum Einsatz in einem fluiden Medium
US8283999B2 (en) * 2010-02-23 2012-10-09 Avago Technologies Wireless Ip (Singapore) Pte. Ltd. Bulk acoustic resonator structures comprising a single material acoustic coupling layer comprising inhomogeneous acoustic property
US8413762B1 (en) * 2011-12-08 2013-04-09 Gulfstream Aerospace Corporation Thermal-acoustic sections for an aircraft
US11007686B2 (en) * 2014-10-01 2021-05-18 Surf Technology As Ultrasound transducer matching layers and method of manufacturing
WO2016077560A1 (fr) * 2014-11-12 2016-05-19 The Trustees Of Dartmouth College Matériau piézo-électrique poreux à surface dense, et procédés et dispositifs associés
JP6572812B2 (ja) * 2016-03-23 2019-09-11 横浜ゴム株式会社 音響透過性部材
CN110400869A (zh) * 2019-06-19 2019-11-01 中国科学院声学研究所东海研究站 一种可控声阻抗的介质及其声阻抗调控方法
WO2022238326A1 (fr) * 2021-05-10 2022-11-17 Koninklijke Philips N.V. Couches d'adaptation acoustique à gradient
WO2023190097A1 (fr) * 2022-03-28 2023-10-05 テイカ株式会社 Couche d'adaptation acoustique à base de céramique, son procédé de fabrication et son utilisation

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EP0119855A2 (fr) * 1983-03-17 1984-09-26 Matsushita Electric Industrial Co., Ltd. Transducteurs ultrasonores ayant des couches d'adaptation d'impédance acoustique

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0171716A2 (fr) * 1984-08-16 1986-02-19 Siemens Aktiengesellschaft Procédé pour la fabrication d'une matière poreuse piézoélectrique et matière produite selon le procédé
EP0171716A3 (en) * 1984-08-16 1987-07-29 Siemens Aktiengesellschaft Berlin Und Munchen Process for making a porous piezoelectric material and material made according to the process
EP0361757A2 (fr) * 1988-09-29 1990-04-04 British Gas plc Dispositif d'adaptation
EP0361757A3 (fr) * 1988-09-29 1991-09-25 British Gas plc Dispositif d'adaptation
GB2225426B (en) * 1988-09-29 1993-05-26 Michael John Gill A transducer
EP0421286A2 (fr) * 1989-10-03 1991-04-10 Richard Wolf GmbH Transducteur piézoélectrique
EP0421286A3 (en) * 1989-10-03 1992-06-03 Richard Wolf Gmbh Piezoelectric transducer
EP0629992A2 (fr) * 1993-06-15 1994-12-21 Hewlett-Packard Company Microrainures pour l'apodisation et la focalisation des transducteurs cliniques ultrasonores à large bande
EP0629992A3 (fr) * 1993-06-15 1995-10-25 Hewlett Packard Co Microrainures pour l'apodisation et la focalisation des transducteurs cliniques ultrasonores à large bande.
EP0707898A2 (fr) * 1994-10-21 1996-04-24 Hewlett-Packard Company Procédé pour former intégralement un transducteur et des couches d'adaptation d'impédance
EP0707898A3 (fr) * 1994-10-21 1997-07-23 Hewlett Packard Co Procédé pour former intégralement un transducteur et des couches d'adaptation d'impédance

Also Published As

Publication number Publication date
EP0173864B1 (fr) 1989-07-26
US4686409A (en) 1987-08-11
DE3430161A1 (de) 1986-02-27
JPS6153899A (ja) 1986-03-17
JPH0644837B2 (ja) 1994-06-08
ATE45054T1 (de) 1989-08-15
DE3571887D1 (en) 1989-08-31

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