EP0421286B1 - Piezoelektrischer Wandler - Google Patents

Piezoelektrischer Wandler Download PDF

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Publication number
EP0421286B1
EP0421286B1 EP90118633A EP90118633A EP0421286B1 EP 0421286 B1 EP0421286 B1 EP 0421286B1 EP 90118633 A EP90118633 A EP 90118633A EP 90118633 A EP90118633 A EP 90118633A EP 0421286 B1 EP0421286 B1 EP 0421286B1
Authority
EP
European Patent Office
Prior art keywords
layer
transducer elements
piezoelectric transducer
transducer
transducer according
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.)
Expired - Lifetime
Application number
EP90118633A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0421286A2 (de
EP0421286A3 (en
Inventor
Dagobert Schäfer
Werner Krauss
Peter Jaggy
Helmut Wurster
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Richard Wolf GmbH
Original Assignee
Richard Wolf GmbH
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Filing date
Publication date
Application filed by Richard Wolf GmbH filed Critical Richard Wolf GmbH
Publication of EP0421286A2 publication Critical patent/EP0421286A2/de
Publication of EP0421286A3 publication Critical patent/EP0421286A3/de
Application granted granted Critical
Publication of EP0421286B1 publication Critical patent/EP0421286B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
    • B06B1/0607—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using multiple elements
    • B06B1/0622—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using multiple elements on one surface
    • 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 a piezoelectric transducer for generating focused ultrasonic shock waves for use in lithotripsy with the features of the preamble of claim 1.
  • Piezoelectric transducers are generally known, for example from DE-PS 34 25 992.
  • the use of a coupling medium for coupling the ultrasonic shock waves to the patient's body in such transducers is also well known.
  • the energy densities that can be generated with piezoelectric materials are very high, but only a very small part of the available energy is introduced into the coupling medium (water or oil) in practice, since the sound-producing ceramic and the water / oil are acoustically very strong differentiate from each other.
  • the known transducer is designed so that between the transducer elements and the coupling medium, an intermediate medium is provided at least from one layer, the acoustic impedance of which is between that of the ceramic of the transducer elements and that of the coupling medium and that the thickness of the layer is dimensioned such that the relationship d> ⁇ k .c LA applies, where ⁇ k is the propagation time of the sound in the piezoceramic of the transducer elements and c LA is the speed of sound in the respective intermediate medium.
  • the thickness of the layer of the intermediate medium cannot be measured on the basis of the wavelength of the ultrasound, since the ultrasound shock waves generated by the transducer have a very wide frequency spectrum.
  • an adaptation as known from US-PS 415 6863, does not provide anything for the present task solution. This is because there is only provision for the thickness of one Potting compound, which has the acoustic impedance of the coupling medium (water), to be dimensioned to a quarter of the wavelength of the sound waves emanating from the individual transducers.
  • the requirements for impedance matching are completely different.
  • a layer of the intermediate medium is introduced between the active surface of each piezoelectric transducer element and the coupling medium, it must have a certain thickness and a certain acoustic impedance in order to achieve optimal results.
  • the acoustic impedance to be selected depends on the acoustic conditions at the interface between the active transducer elements and the layer of the intermediate medium or on the known sound transmission factors at the interface between two media of different acoustic impedance. In any case, it lies between that of the ceramic of the transducer elements and that of the coupling medium.
  • the acoustic thickness of the layer of the intermediate medium must be greater than that of the ceramic of the transducer elements.
  • the effect that more energy gets into the coupling medium can be increased in that several layers of intermediate media are provided between the transducer elements and the coupling medium, the acoustic impedances of which decrease from the first layer on the transducer elements in the direction of radiation of the ultrasonic shock waves.
  • the layer or the layers of the intermediate media can each be assigned to one transducer element, uniformly all transducer elements together or mixed partially uniformly together and partially in each case to one transducer element.
  • the described construction of the transducer according to the invention can be implemented in the case of self-focusing transducers, for example dome-shaped transducers, but also in the case of planar transducers.
  • At least a layer of an intermediate medium is designed as an acoustic lens. This layer then takes over the task of focusing the ultrasonic shock waves on the focus of the transducer, so that no additional effort is required.
  • the transducer in the direction of radiation of the ultrasonic shock waves, has a layer of an intermediate medium on the transducer elements, which has a surface that electrically connects the transducer elements and faces them. This surface is then connected to one pole of the pulse generator.
  • the first layer is thus used as a common electrode for all transducer elements, which not only significantly reduces the amount of wiring previously required, but also makes the transducer overall more compact and less susceptible to faults.
  • the first layer is solid and metallic.
  • Aluminum for example, is suitable for this purpose, the acoustic impedance of which corresponds to the conditions mentioned.
  • this embodiment can advantageously be developed further in that the layer is constructed as a solid, acoustic lens. This then again takes on the task of focusing the ultrasonic shock waves on the converter focus.
  • Each transducer element has a so-called backing, the acoustic impedance is at least as large as that of the ceramic of the individual transducer elements. This measure ensures an almost reflection-free termination of the transducer elements, so that unwanted negative tensile impulses for lithotripsy are limited to a practically possible minimum.
  • the backings can be designed in such a way that the sound coming from the ceramic is scattered so that it does not in the focus of the converter, which can be achieved, for example, by roughening the back of the backings or by shaping it into a cone, for example.
  • transducer elements can also be provided with a common backing for their reflection-free termination.
  • the energy density of the ultrasonic shock waves in the transducer focus compared to previous transducers has been increased by "passive” measures through the better coupling of the ultrasonic shock waves into the coupling medium, that is, through the better utilization of the energy generated by the transducer elements.
  • some of the described embodiments also allow the energy density in the converter focus to be increased by “active” measures. This relates in particular to the control of the converter elements by means of higher voltages. Up to now, this was not easily possible primarily due to safety aspects, but also with regard to the converter's service life.
  • the transducer elements with the electrically conductive carrier by means of electrically conductive fasteners are clamped, the carrier being connected to the other pole of the pulse generator. This makes it possible to control the converter elements with higher voltages without the converter elements bursting out of their anchoring, which would result in irreparable damage.
  • a higher controllability with higher voltages, whereby the output power of the converter is actively increased, can be achieved in the embodiments of the converter described above, in which the first layer of an intermediate medium on the converter elements is solid and metallic and thus serves as an electrode that the space outlined by the first layer, the common backing, or the support is liquid-tight and gas-tight by means of electrically non-conductive side walls, and that this space is filled with a highly insulating medium.
  • a gas, oil or also a solid insulator can be considered as a highly insulating medium.
  • the transducer in such a way that an electrically conductive first layer forms the carrier, which is connected to one pole of the pulse generator, and that this carrier encloses a liquid-tight and gas-tight space with a housing, which is sealed with a highly insulating Medium is filled.
  • This also results in a relative increase in the energy density of the ultrasonic shock waves generated by the transducer in focus due to a higher radiation power on the one hand and a better coupling of the energy into the coupling medium on the other hand.
  • the first layer consists of a highly insulating potting material which also fills the spaces between the transducer elements.
  • the first layer takes on both the task of impedance matching and the task of lateral electrical insulation of the converter elements from one another, as a result of which the converter can be controlled with higher voltages than before.
  • Polyurethane epoxy mixtures or silicones are particularly suitable as potting material.
  • FIG. 1 shows a dome-shaped and thus self-focusing transducer which bundles the generated ultrasonic shock wave from the piezoelectric transducer elements onto the focus 15 via a coupling medium 20.
  • the transducer elements 2 are attached to a carrier 8 with their active surface.
  • the carrier 8 is identical to the first layer 3, the thickness of which depends on the relationship d> ⁇ k .
  • c LA is dimensioned, where ⁇ k is the transit time of the sound in the piezoceramic of the transducer elements 2 and c LA is the speed of sound in the layer 3.
  • a further layer 4 of an intermediate medium serving for impedance matching is applied to layer 3, the acoustic impedance of which lies between that of layer 3 and that of coupling medium 20.
  • the above relationship applies correspondingly to the thickness of layer 4, where c LA is the speed of sound in layer 4.
  • the layer 3 or the carrier 8 is solid and metallic, that is to say electrically conductive. It serves as a common electrode for all converter elements 2 and is accordingly connected to one pole of a pulse generator 7.
  • the other pole of the generator 7 is connected via a wiring 11 at the rear end of the converter elements 2 via electrically conductive individual backings 6.
  • the conical shape of the backings 6 causes sound coming from the back to be scattered in such a way that it is not focused in the focus 15.
  • Aluminum is considered as the material for the layer 3 or the carrier 8 if water is the coupling medium 20 is used.
  • the formation of the first layer 3 as a solid support 8 enables it to enclose a liquid and gas-tight space with a housing 21, which is filled with a highly insulating medium 18.
  • the medium 18 prevents a jump of sparks at the individual converter elements 2 at a high voltage applied to the elements 2. Accordingly, this converter can be controlled with a voltage which enables a significantly higher output compared to known converters.
  • FIG. 2 shows an embodiment of a dome-shaped transducer in which the transducer elements 2 are braced on the back with electrically conductive individual backings 6 and with an electrically conductive carrier 8 by means of screws 9.
  • Two layers 3 and 4 of intermediate media are applied to the converter elements 2 in order to adapt the impedance to the coupling medium (not shown).
  • the first layer 3 is electrically conductive. It is used to supply the voltage from the pulse generator 7 to the converter elements 2.
  • the other pole of the generator 7 is connected to the converter elements 2 via the carrier 8, screws 9 and backings 6.
  • FIG. 3 shows a planar transducer in which the transducer elements with the individual backings 6 are clamped to the carrier 8 by screws 9.
  • the adaptation of the acoustic impedance is achieved here by three layers 3, 4 and 5 of intermediate media on the transducer elements 2 of course, the conditions mentioned above for their acoustic impedances are met.
  • Layer 5 is assigned to all transducer elements 2 together here. It is also designed as an acoustic lens which, together with the first matching layer (3), focuses the emitted ultrasonic shock waves.
  • FIG. 4 also shows a planar transducer, in which three layers 3, 4 and 5 of intermediate media are applied to the transducer elements 2, as already explained in connection with the exemplary embodiment according to FIG. 3, in the radiation direction of the ultrasonic shock waves.
  • the middle layer 4 is provided as a common layer and designed as a focusing acoustic lens.
  • electrically non-conductive side walls 16, the common carrier 8 and the layer 4 outline a liquid and gas-tight space which is filled with a highly insulating medium 18.
  • the converter elements have a common backing 14, which also closes the space outlined by the first layer 3 and the electrically non-conductive side walls 16, in which a highly insulating medium 18 is located.
  • the back of the backing 14 is designed so that sound reflected from it is no longer focused in the focus of the transducer.
  • All layers 3 to 6 are common for All transducer elements are provided, layers 4 and 5 being designed as lenses for focusing the ultrasonic shock waves.
  • FIG. 7 shows, the use of a common backing 14 is also possible with a dome-shaped converter.
  • the layers 3 and 4 of the intermediate media are each assigned to a converter element 2.
  • FIG. 8 shows an extreme case in which the piezoceramic material 2 is in one piece. This is completed on the back by a backing 14. The impedance matching is done by two layers 3 and 4 of coupling media.
  • FIG. 9 shows a particularly preferred embodiment of the converter. Only one layer 3 of an intermediate medium is shown here.
  • Layer 3 consists of a highly insulating potting material, for which, for example, polyurethanes, epoxy mixtures or silicones can be used.
  • the potting material has an acoustic impedance which again lies between that of the ceramic of the transducer elements 2 and that of the coupling medium 20.
  • the spaces 22 between the individual transducer elements 2 are filled with it.
  • this converter can be controlled with higher voltages than known converters.
  • it has the advantage that the transducer elements 2 are embedded in the potting compound with absolute water protection, which results in an outstanding immunity to interference by the transducer.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Mechanical Engineering (AREA)
  • Transducers For Ultrasonic Waves (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
EP90118633A 1989-10-03 1990-09-28 Piezoelektrischer Wandler Expired - Lifetime EP0421286B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3932959A DE3932959C1 (es) 1989-10-03 1989-10-03
DE3932959 1989-10-03

Publications (3)

Publication Number Publication Date
EP0421286A2 EP0421286A2 (de) 1991-04-10
EP0421286A3 EP0421286A3 (en) 1992-06-03
EP0421286B1 true EP0421286B1 (de) 1994-11-09

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP90118633A Expired - Lifetime EP0421286B1 (de) 1989-10-03 1990-09-28 Piezoelektrischer Wandler

Country Status (3)

Country Link
US (1) US5111805A (es)
EP (1) EP0421286B1 (es)
DE (2) DE3932959C1 (es)

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SE465552B (sv) * 1989-03-21 1991-09-30 Hans Wiksell Anordning foer soenderdelning av konkrement i kroppen paa en patient
DE3932967A1 (de) * 1989-10-03 1991-04-11 Wolf Gmbh Richard Ultraschall-stosswellenwandler
DE4000362C2 (de) * 1990-01-09 1993-11-11 Wolf Gmbh Richard Ultraschallwandler mit piezoelektrischen Wandlerelementen
DE4117638A1 (de) * 1990-05-30 1991-12-05 Toshiba Kawasaki Kk Stosswellengenerator mit einem piezoelektrischen element
DE4307669C2 (de) * 1993-03-11 1995-06-29 Wolf Gmbh Richard Gerät zur Erzeugung von Schallimpulsen für den medizinischen Anwendungsbereich
US5743855A (en) * 1995-03-03 1998-04-28 Acuson Corporation Broadband phased array transducer design with frequency controlled two dimension capability and methods for manufacture thereof
US5415175A (en) * 1993-09-07 1995-05-16 Acuson Corporation Broadband phased array transducer design with frequency controlled two dimension capability and methods for manufacture thereof
US5438998A (en) * 1993-09-07 1995-08-08 Acuson Corporation Broadband phased array transducer design with frequency controlled two dimension capability and methods for manufacture thereof
DE4336149A1 (de) * 1993-10-22 1995-04-27 Siemens Ag Ultraschallwandler, der aus einer Vielzahl von Wandlerelementen zusammengesetzt ist
US5371483A (en) * 1993-12-20 1994-12-06 Bhardwaj; Mahesh C. High intensity guided ultrasound source
FI95781C (fi) * 1994-04-19 1996-03-25 Outokumpu Mintec Oy Menetelmä ja laitteisto imukuivainlaitteen suodatinväliaineen puhdistamiseksi
DE19507478C1 (de) * 1995-03-03 1996-05-15 Siemens Ag Therapiegerät zur Behandlung mit fokussiertem Ultraschall
US5713371A (en) * 1995-07-07 1998-02-03 Sherman; Dani Method of monitoring cervical dilatation during labor, and ultrasound transducer particularly useful in such method
DE19543741C1 (de) * 1995-11-24 1997-05-22 Wolf Gmbh Richard Elektroakustischer Wandler
DE19624443C2 (de) * 1996-06-19 1998-05-14 Wolf Gmbh Richard Elektroakustischer Wandler
US6669655B1 (en) * 1999-10-20 2003-12-30 Transurgical, Inc. Sonic element and catheter incorporating same
DE19954020C2 (de) * 1999-11-10 2002-02-28 Fraunhofer Ges Forschung Verfahren zur Herstellung eines piezoelektrischen Wandlers
US6571444B2 (en) * 2001-03-20 2003-06-03 Vermon Method of manufacturing an ultrasonic transducer
US7867178B2 (en) * 2003-02-26 2011-01-11 Sanuwave, Inc. Apparatus for generating shock waves with piezoelectric fibers integrated in a composite
DE10340624B4 (de) * 2003-09-03 2005-08-18 Siemens Ag Stoßwellenquelle zum Erzeugen einer fokussierten Stoßwelle
US7302744B1 (en) 2005-02-18 2007-12-04 The United States Of America Represented By The Secretary Of The Navy Method of fabricating an acoustic transducer array
US20070239082A1 (en) * 2006-01-27 2007-10-11 General Patent, Llc Shock Wave Treatment Device
EP2092916A1 (en) * 2008-02-19 2009-08-26 Institut National De La Sante Et De La Recherche Medicale (Inserm) A method of treating an ocular pathology by applying high intensity focused ultrasound and device thereof
US7709997B2 (en) * 2008-03-13 2010-05-04 Ultrashape Ltd. Multi-element piezoelectric transducers
DE102009049487B4 (de) * 2009-10-15 2015-05-13 Richard Wolf Gmbh Elektroakustischer Wandler
EP2608897B1 (en) 2010-08-27 2023-08-02 SOCPRA Sciences et Génie s.e.c. Mechanical wave generator and method thereof
WO2013082352A1 (en) 2011-12-01 2013-06-06 Microbrightfield, Inc. Acoustic pressure wave/shock wave mediated processing of biological tissue, and systems, apparatuses, and methods therefor
US20130340530A1 (en) * 2012-06-20 2013-12-26 General Electric Company Ultrasonic testing device with conical array
US9555267B2 (en) 2014-02-17 2017-01-31 Moshe Ein-Gal Direct contact shockwave transducer
CN109939914A (zh) * 2017-12-20 2019-06-28 深圳先进技术研究院 一种复合材料物理聚焦式换能器及其制造方法
CN111940098B (zh) * 2020-04-08 2021-11-12 珠海艾博罗生物技术股份有限公司 侧面励振式超声处理器及处理方法
DE102021203544A1 (de) 2021-04-09 2022-10-13 Richard Wolf Gmbh Elektroakustischer Wandler

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DE3430161A1 (de) * 1984-08-16 1986-02-27 Siemens AG, 1000 Berlin und 8000 München Poroese anpassungsschicht in einem ultraschallapplikator
DE3437488A1 (de) * 1984-10-12 1986-04-17 Richard Wolf Gmbh, 7134 Knittlingen Schallsender
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JPS61144565A (ja) * 1984-12-18 1986-07-02 Toshiba Corp 高分子圧電型超音波探触子
EP0209053A3 (de) * 1985-07-18 1987-09-02 Wolfgang Prof. Dr. Eisenmenger Verfahren und Einrichtung zur berührungsfreien Zertrümmerung von Konkrementen im Körper von Lebewesen
US4879993A (en) * 1986-10-29 1989-11-14 Siemens Aktiengesellschaft Shock wave source for generating a short initial pressure pulse
DE8710118U1 (es) * 1987-07-23 1988-11-17 Siemens Ag, 1000 Berlin Und 8000 Muenchen, De
EP0324948A3 (de) * 1988-01-21 1989-10-25 Dornier Medizintechnik Gmbh Vorrichtung zur Steinzerkleinerung
US4869768A (en) * 1988-07-15 1989-09-26 North American Philips Corp. Ultrasonic transducer arrays made from composite piezoelectric materials
DE8815090U1 (es) * 1988-12-03 1990-02-15 Dornier Medizintechnik Gmbh, 8000 Muenchen, De

Also Published As

Publication number Publication date
DE3932959C1 (es) 1991-04-11
EP0421286A2 (de) 1991-04-10
EP0421286A3 (en) 1992-06-03
US5111805A (en) 1992-05-12
DE59007688D1 (de) 1994-12-15

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