EP0590193A1 - Transducteur ultrasonore muni d'une couche d'adaptation acoustique - Google Patents

Transducteur ultrasonore muni d'une couche d'adaptation acoustique Download PDF

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Publication number
EP0590193A1
EP0590193A1 EP92116764A EP92116764A EP0590193A1 EP 0590193 A1 EP0590193 A1 EP 0590193A1 EP 92116764 A EP92116764 A EP 92116764A EP 92116764 A EP92116764 A EP 92116764A EP 0590193 A1 EP0590193 A1 EP 0590193A1
Authority
EP
European Patent Office
Prior art keywords
acoustic
ultrasonic transducer
transducer
transducer arrangement
adaptation layer
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.)
Withdrawn
Application number
EP92116764A
Other languages
German (de)
English (en)
Inventor
Clemens Dr. Ing. Fiebiger
Erhard Ing. Grad. Schmidt
Karl Dipl.-Phys. Prestele
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.)
Siemens AG
Original Assignee
Siemens AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Priority to EP92116764A priority Critical patent/EP0590193A1/fr
Priority to JP5242537A priority patent/JPH06225393A/ja
Publication of EP0590193A1 publication Critical patent/EP0590193A1/fr
Withdrawn legal-status Critical Current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
    • B06B1/0644—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 a single piezoelectric element
    • B06B1/0662—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 a single piezoelectric element with an electrode on the sensitive surface
    • B06B1/067—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 a single piezoelectric element with an electrode on the sensitive surface which is used as, or combined with, an impedance matching layer
    • 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 ultrasound transducer arrangement with an electroacoustic transducer part and at least one acoustic adaptation layer arranged in a sound path.
  • adaptation layers are used in order to reduce reflections at the interfaces of two materials with different acoustic impedance in the sound path or in the direction of sound emission and / or sound reception outside of an object to be examined, or to transmit the sound energy from the transducer part to a medium to be examined and back with as little loss as possible .
  • at least one adaptation layer is arranged between the two materials.
  • adaptation layers are used to acoustically adapt the electroacoustic transducer part to an examination object.
  • an acoustic sump or damping body can also be adapted to the transducer part directly or with at least one adaptation layer.
  • Adaptation layers made of a synthetic resin such as Epoxy resin, in which the smallest particles of a mineral or metallic material are embedded.
  • the acoustic impedance of the matching layer is essentially dependent on the amount and the material of the added particles.
  • a uniform distribution of the particles in the synthetic resin cannot always be achieved over larger volume ranges.
  • the reproducibility of the function-determining acoustic properties is limited.
  • u. U. Inhomogeneities and imperfections have to be accepted.
  • Many suitable resins are also sensitive to external influences, in particular they swell when exposed to moisture. As a result, there is a risk that the adhesive surfaces of the matching layers become detached.
  • the invention is based on the object of specifying an acoustic adaptation layer which is insensitive to external influences and whose function-determining acoustic properties are easily reproducible.
  • the acoustic adaptation layer consists of a paracrystalline carbon.
  • Paracrystalline carbon also known as amorphous carbon, has the type of crystallinity that produces diffuse X-ray reflections due to the smallness of the strictly periodic areas. That is why it is also called X-ray amorphous.
  • Paracrystalline carbon is insensitive to external influences, in particular water absorption and water permeability are negligible. Due to the largely homogeneous and pore-free structure, the function-determining acoustic properties easily reproducible.
  • paracrystalline carbon is electrically conductive, this property can be used for contacting the converter part or for shielding purposes. A relatively high sound velocity of this material leads, particularly at high frequencies of the order of 5 to 10 MHz, to greater, ie also easier to handle, thicknesses of the adaptation layer.
  • the acoustic transducer part comprises a polarized piezoceramic.
  • Polarized piezoceramic has a relatively high acoustic impedance on the order of 35 MRayl.
  • the speed of sound and the attenuation of the paracrystalline carbon are reproducible within narrow limits and specified by the production. These properties result in an acoustic impedance of approx. 7 MRayl. It is therefore well suited for matching layers that connect the piezoceramic acoustic transducer part to a medium with low acoustic impedance in the order of 1.5 MRayl, such as Water or body tissues.
  • the electroacoustic transducer part is designed for medical applications.
  • Medical use is understood to mean both a therapeutic and a diagnostic use.
  • Paracrystalline carbon has particularly favorable acoustic properties for this adaptation problem, the wave resistance and the speed of sound are in a favorable range.
  • the negligible sound attenuation of the paracrystalline carbon is advantageous for medical applications.
  • the acoustic adaptation layer borders directly on a radiating surface of the transducer part.
  • a combination of piezoceramic and paracrystalline carbon is particularly advantageous because the coefficients of thermal expansion of the piezoceramic and paracrystalline carbon are approximately the same. This ensures a high alternating load resistance of the transducer arrangement, which is of particular importance in the case of power transducers for therapeutic purposes.
  • the electrical conductivity of paracrystalline carbon is used for contacting and / or for shielding.
  • the paracrystalline carbon is a glass-like carbon.
  • Glassy carbon is available under various trade names with wall thicknesses up to 4 mm in many desired shapes.
  • the ultrasonic transducer arrangement 4 comprises an electroacoustic transducer part 8.
  • the electroacoustic transducer part 8 consists of a round piezoelectric ceramic disk 10 which is provided with electrodes 12 and 13 on opposite flat sides.
  • the piezoelectric ceramic disk 10 has an acoustic impedance of approximately 35 MRayl.
  • the high acoustic impedance of the transducer part 8 is matched to an ultrasound propagation medium 14 with an acoustic matching layer 16. Water with an acoustic impedance of approximately 1.5 MRayl is used here as the ultrasound propagation medium 14.
  • the acoustic matching layer 16 consists of a glassy carbon, such as e.g. is sold under the name SIGRADUR-K.
  • the acoustic adaptation layer 16, like the transducer part 8, is designed as a round disk.
  • the adaptation layer 16 is electrically conductively connected to the electrode 13 of the electroacoustic transducer part 8, for example by soldering or gluing.
  • the diameter of the acoustic adaptation layer 16 is larger here than the diameter of the electroacoustic transducer part 8, so that the ultrasound transducer arrangement can be placed from the outside onto a projection 18 running around the opening 6. Since the vitreous carbon is impermeable to water and gases, an edge seal 20 made of silicone material arranged on the side of the adaptation layer 16 is sufficient to prevent the liquid ultrasound propagation medium 14 from penetrating into the interior of the housing 2.
  • the electrical conductivity of the acoustic adaptation layer 16 enables electrodes to be easily contacted when the adaptation layer 16 is directly adjacent to the transducer part 8.
  • the acoustic adaptation layer 16 is used here to contact the electrode 13 lying in the radiation direction via the housing 2.
  • an electrical connection 24 is connected directly to the electrode 12 and a second electrical connection 26 to the housing 2, which is connected to the electrode 13 in an electrically conductive manner via the acoustic adaptation layer 16.
  • the electroacoustic transducer part 8 consists of a transducer array 30, which consists of a plurality of similar piezoelectric ceramic cuboids arranged next to one another.
  • the ceramic blocks are each with an opposite side Provide electrodes 12 and 13.
  • the electrodes 12 are each individually connected to electrical connections (not shown here).
  • the elementary transducers thus formed from the ceramic cuboids can be activated individually, so that an examination object 32 can be scanned electronically with ultrasound beams in order to produce a sectional image.
  • the acoustic impedance of the examination object, i.e. body tissue, is around 1.5 MRayl.
  • the electrodes 12 of all elementary transducers are connected to a damping body 34 which ensures that the elementary transducers briefly decay and decay.
  • the damping body 34 can also be acoustically adapted to the piezoelectric ceramic material of the transducer array 30 via an adaptation layer made of glass-like carbon.
  • an adaptation layer 16 made of vitreous carbon is arranged for acoustic adaptation, the thickness of which is approximately a quarter of the wavelength of an ultrasonic wave in the adaptation layer 16.
  • the adaptation layer 16 is glued directly to the electrodes 13 and additionally serves for the acoustic adaptation of the common electrical signal supply on the radiation side.
  • a thin plastic layer 36 covers the adaptation layer 16 in order to achieve a further broadband adaptation to body tissue in the case of medical diagnostic converters.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
  • Transducers For Ultrasonic Waves (AREA)
EP92116764A 1992-09-30 1992-09-30 Transducteur ultrasonore muni d'une couche d'adaptation acoustique Withdrawn EP0590193A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP92116764A EP0590193A1 (fr) 1992-09-30 1992-09-30 Transducteur ultrasonore muni d'une couche d'adaptation acoustique
JP5242537A JPH06225393A (ja) 1992-09-30 1993-09-29 超音波変成装置

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP92116764A EP0590193A1 (fr) 1992-09-30 1992-09-30 Transducteur ultrasonore muni d'une couche d'adaptation acoustique

Publications (1)

Publication Number Publication Date
EP0590193A1 true EP0590193A1 (fr) 1994-04-06

Family

ID=8210089

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92116764A Withdrawn EP0590193A1 (fr) 1992-09-30 1992-09-30 Transducteur ultrasonore muni d'une couche d'adaptation acoustique

Country Status (2)

Country Link
EP (1) EP0590193A1 (fr)
JP (1) JPH06225393A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2288741A (en) * 1994-04-30 1995-11-01 Orthosonics Ltd Ultrasonic impedance-matching therapy device
WO1997008546A1 (fr) * 1995-08-31 1997-03-06 Alcan International Limited Sondes a ultrasons destinees a etre utilisees dans des milieux durs
WO1999032858A1 (fr) * 1997-12-23 1999-07-01 Simmonds Precision Products, Inc. Dispositif a ultrasons pour la mesure de niveau de liquide

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
IEEE TRANSACTIONS ON SONICS AND ULTRASONICS Bd. SU-31, Nr. 2, März 1984, NEW YORK US Seiten 101 - 104 L.C.LYNNWORTH E.A. 'Impedance-matched metallurgical sealed transducers' *
PATENT ABSTRACTS OF JAPAN vol. 5, no. 026 (P-049)17. Februar 1981 & JP-A-55 151 258 ( HITACHI LTD ) 25. November 1980 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2288741A (en) * 1994-04-30 1995-11-01 Orthosonics Ltd Ultrasonic impedance-matching therapy device
GB2288741B (en) * 1994-04-30 1998-03-11 Orthosonics Ltd Ultrasonic therapeutic system
WO1997008546A1 (fr) * 1995-08-31 1997-03-06 Alcan International Limited Sondes a ultrasons destinees a etre utilisees dans des milieux durs
AU703366B2 (en) * 1995-08-31 1999-03-25 Alcan International Limited Ultrasonic probes for use in harsh environments
WO1999032858A1 (fr) * 1997-12-23 1999-07-01 Simmonds Precision Products, Inc. Dispositif a ultrasons pour la mesure de niveau de liquide

Also Published As

Publication number Publication date
JPH06225393A (ja) 1994-08-12

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