EP0166180B1 - Hydrophone - Google Patents

Hydrophone Download PDF

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Publication number
EP0166180B1
EP0166180B1 EP85106107A EP85106107A EP0166180B1 EP 0166180 B1 EP0166180 B1 EP 0166180B1 EP 85106107 A EP85106107 A EP 85106107A EP 85106107 A EP85106107 A EP 85106107A EP 0166180 B1 EP0166180 B1 EP 0166180B1
Authority
EP
European Patent Office
Prior art keywords
hydrophone according
receiving elements
carrier
base body
hydrophone
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
Application number
EP85106107A
Other languages
German (de)
English (en)
Other versions
EP0166180A1 (fr
Inventor
Bernd Dr. Granz
Bertram Sachs
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
Publication of EP0166180A1 publication Critical patent/EP0166180A1/fr
Application granted granted Critical
Publication of EP0166180B1 publication Critical patent/EP0166180B1/fr
Expired 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S310/00—Electrical generator or motor structure
    • Y10S310/80—Piezoelectric polymers, e.g. PVDF

Definitions

  • the invention relates to a hydrophone with a flat piezoelectric base body.
  • the electrically active area of the base body is polarized in the direction of the thickness of the film and has only a very small extent in the plane of the flat sides of the base body.
  • Such miniature hydrophones are known to measure ultrasonic fields in a sound-carrying medium.
  • a membrane made of polyvinylidene fluoride PVDF or copolymers of vinylidene fluoride with tetrafluoroethylene or also with trifluoroethylene with a thickness of about 25 J.Lm, for example, can be provided as the base body, which can be stretched as a membrane between two metal rings. At its center is the piezoelectrically active area, which is provided with electrodes and forms a receiving element.
  • the film can also be stretched at the end of a coaxial cable and its piezoelectrically active region with an extent of approximately 1 mm can be arranged approximately on the tip of a needle.
  • the receiving elements have a diameter of approximately 2 mm and their capacitance is approximately 8 pF.
  • a preamplifier is connected to a cable about 30 cm long. (J. Soc Accoust Am, Vol 61, .Suppi No. 1, Spring 1977, pp S 17 and S 18......) 10 6 V / Pa - With this arrangement, one obtains a sensitivity of about 3.2 .
  • the invention is now based on the knowledge that the expansion of the receiving elements cannot be limited arbitrarily because metallic electrodes adhere poorly to the polymer film.
  • the sensitivity can only be increased if an electronic amplifier element, preferably a field effect transistor, is assigned to each receiving element, which must be arranged in the immediate vicinity of the receiving element.
  • a connection of an amplifier located relatively far away loads the receiving element by the line capacitance C L and leads to a reduced voltage U in accordance with a capacitance C E of the receiving element and a receiver voltage U E
  • a coaxial cable for example, has a line capacitance of approximately 1 pF / cm, so that, for example, with a 30 cm line, the receiver voltage is reduced to C E / 30 pF. If, on the other hand, the impedance has already changed at the output of the amplifier, a line can then be routed to other parts of the amplifier. If a larger number of receiving elements are arranged close to one another, then the associated amplifiers must also be arranged in approximately the same grid dimension.
  • the invention is therefore based on the object of improving this known miniature hydrophone, in particular a hydrophone is to be specified with which even unknown ultrasonic fields of greater extent can be measured in a short time and in a simple manner. Furthermore, the usability and sensitivity should be increased.
  • a linear arrangement of transducer elements in the embodiment as a transverse oscillator is attached to the narrow side of a common, flat substrate.
  • Opposing surfaces of the transducer elements that run parallel to the polarization axis are each provided with a metallization.
  • the free end faces of the transducer elements serve to emit the ultrasound.
  • the transducer elements are made by cuts perpendicular to the end face and electrically isolated from one another.
  • the flat sides of the substrate are provided with electrodes using thin-film technology and are connected in an electrically conductive manner to the metallizations of the transducer elements.
  • the required electronics in thin-film technology are arranged on one of the flat sides of the substrate (GB-A-2 052 918).
  • an ultrasound pickup for two-dimensional image scanning is known with discrete ultrasound transducers, each of which is assigned a flexible printed circuit board which is provided with an integrated circuit.
  • the leads are of unequal lengths (GB-A-1 530 783).
  • Another known ultrasonic transducer arrangement with several transducer elements for absorbing ultrasonic vibrations from a sound-carrying medium contains a film made of polyvinylidene fluoride PVDF as the base body.
  • This base body is on one of its flat sides in predetermined piezoelectrically active areas, each of which forms one of the transducer elements, with one Electrode made of electrically conductive material.
  • the film is polarized in the direction of its thickness only in these regions and its electrodes are arranged on one flat side on a base body.
  • This monolithic embodiment of an ultrasonic transducer arrangement forms a broadband reception array with high sensitivity (DE-A-31 49 732).
  • the thickness of the electrodes which are preferably fastened, for example vapor-deposited, on a top surface of the carrier body, will generally not substantially exceed a few ⁇ m and preferably be substantially less than 1 JJ.m.
  • the assigned electrical connection conductors must not significantly exceed this thickness. They can be produced in a relatively simple manner in the same operation with the electrodes, for example in a photolithographic process.
  • the surface areas of the top surface and the side surface adjacent to the edge can be provided with a groove which is directed perpendicular to the edge. Within these grooves, at least part of the surface is provided with a metallization, with the aid of which the line connection between the electrodes and the electrical elements mentioned is established, for example by a solder contact (DE-A-32 46 661).
  • the invention makes use of these known design features of an ultrasonic transducer arrangement and consists in the characterizing features of claim 1.
  • the extension of the receiving elements in the plane of the flat sides of the base body is generally less than 1 mm and their distance is limited to not much more than one tenths of a millimeter. Since the extension of the assigned amplifiers, preferably hybrid amplifiers, does not significantly exceed these dimensions, this also results in a grid dimension of the linear arrangement of less than 1 mm.
  • This hydrophone has a sensitivity of at least 10- 5 V / Pa. To measure an ultrasound field, only a shift in one direction transverse to the linear arrangement of the receiving elements is required.
  • the distance between the first and last receiving element from the beginning and the end of the carrier body is only about half the distance between the receiving elements.
  • a larger number of modules can thus be arranged in succession in the linear direction of expansion of the receiving elements to form a common structural unit with the same grid dimension, with which ultrasonic fields of greater extent can also be measured in a short time.
  • a receiving element 10 is formed from the piezoelectrically active region 3 of a base body 2, indicated by dashed lines in the figure, to which an electrode 4 is assigned on its upper flat side and an electrode 5 on its lower flat side, which is on a carrier body 16 is attached.
  • the electrode 5 is capacitively coupled to the piezoelectrically active region 3 of the base body 2 by means of an electrically non-conductive adhesive layer 6 with a high dielectric constant.
  • the lower electrode 5 is provided with an electrical connecting conductor 11.
  • a connecting conductor 12 can be seen in the figure from the receiving element adjacent in a linear arrangement of the receiving elements 10.
  • the top surface 15 of the carrier 16 is laterally delimited by two inclined side surfaces 17 and 18, which each form an edge 22 or 23 with the top surface 15.
  • edges 22 and 23 are each provided in the area of the connecting conductors 11 and 12 with a groove 24 and 25, which are directed perpendicular to the edge 22 and 23, and their inner surfaces each at least partially with a metallization, not shown in the figure are provided.
  • the metallization in the groove 24 serves, for example, as an electrical connection, preferably for soldering, of a connecting conductor 26 for an amplifier 32 assigned to the receiving element 10 and arranged on a substrate 33.
  • An associated connecting conductor 27 and an amplifier 36 which is arranged in the same way on a substrate 37, can be seen in the figure from the adjacent receiving element (not shown in the figure).
  • the base body 2 of the receiving element 10 consists of a film of a polymer, preferably polyvinylidene fluoride PVDF, or also a copolymer of vinylidene fluoride with tetrafluoroethylene or with trifluoroethylene, with a thickness of approximately 25 ⁇ m, for example, which polarizes in the direction of its thickness in its piezoelectrically active region 3 is.
  • the associated electrodes 4 and 5 are made of metal, the thickness of which preferably does not exceed a few JJ.m and in particular can be significantly less than 1 4 m.
  • Chromium / silver or also chromium / gold is preferably suitable, in which the chromium layer with a thickness of, for example, approximately 20 nm serves as an adhesion promoter, on which then a Silver layer of about 0.2 f.Lm is deposited.
  • the electrode 5 can expediently be applied to the carrier body 16 with its associated connecting conductor 11 in a common operation. in particular vapor-deposited or sputtered on.
  • the electrode 5 is indirectly attached to the base body 2 with the aid of the adhesive layer 6, which consists of an electrically insulating material with a high dielectric constant and can preferably be an adhesive or kit layer.
  • the carrier 16, the so-called backing can preferably consist of a material with high acoustic impedance.
  • hard backing for example ceramic, preferably aluminum oxide A1 2 0 3 , is suitable, the sound impedance of which is approximately 40 ⁇ 10 6 kg / m 2 s. Glass or quartz with a sound impedance of 14 x 10 6 kg / m 2 s is also suitable.
  • a soft backing can also be provided as the carrier 16, which absorbs the ultrasound itself and can be made of rubber, for example.
  • a received ultrasound signal is then capacitively coupled in a frequency range of approximately 1 to at least 10 MHz in the transducer element 10 from the lower flat side of the active region 3 to the electrode 5 and fed to the associated amplifier 32 via the connecting conductors 11 and 26.
  • Hybrid amplifiers which are arranged on a substrate 33, preferably a thin film substrate, are preferably suitable as amplifiers 32. These hybrid amplifiers have a heterogeneous structure.
  • the resistors can preferably be constructed using thin-film technology, while the associated transistors are glued on as transistor chips and their electrically conductive connections are bonded.
  • the receiving element 10 is coupled via an ultrasound coupling medium 38 to a cover film 39, which can consist, for example, of a polymer and can serve as an end wall on the front side of a chamber in which the structural unit shown is arranged.
  • an electrode 4 common to all receiving elements 10 is provided on the upper flat side of the common base body 2 for a plurality of receiving elements 10, which are indicated by dashed lines in the figure.
  • the base body 2 with the adhesive layer 6 is shown for clarity at a certain distance from the lower electrodes 5, which are arranged one behind the other in the linear direction of expansion of a module not shown in the figure, for example 16 receiving elements 10.
  • a grid dimension of the receiving elements 10 of 0.8 mm is obtained, so that the entire length L of the module is approximately 12 mm. This results in a capacitance CE of the receiving elements 10 of approximately -1.6 pF at a frequency of 2 MHz, for example.
  • the amplifiers 32 and 36 assigned to the receiving elements 10 can each be arranged alternately on one of the side surfaces 17 and 18 of the carrier 16.
  • the length of the electrical line connection between the electrode 5 and the associated amplifier 32, which is formed from the connecting conductors 11 and 26, which are connected to one another by means of the metallization within the groove 22, is very short and can be, for example, only about 1 mm and is also the same for all receiving elements 10.
  • the sensitivity of the system consisting of receiving element 10 and amplifier 32 or 36 is thus homogeneous and very high.
  • nV / VHz gives a sensitivity of about 10- 5 V / Pa.
  • the amplifiers 32 are provided with the aid of metallized areas 42 on the surface of the substrate 33 with electrical signal lines 43 which can lead to further components of the amplifiers 32.
  • a module with a multiplicity of receiving elements 10 is arranged in a chamber 40, which is closed on its end face by the cover film 39, which is coupled via the ultrasound coupling medium 38 to the receiving element 10, which is arranged on the carrier 16 is.
  • This carrier 16 consists of a hard backing, at the end facing away from the receiving element 10 an absorber 46 is provided, which can consist, for example, of epoxy resin, which is provided with additives, which can consist, for example, of aluminum oxide powder.
  • the end of the carrier 16 is pointed so that the proportion of an ultrasonic wave that has penetrated into the carrier 16 is reflected by the interface between the absorber 46 and the carrier 16.
  • the walls of chamber 40 are generally made of metal.
  • the cover sheet 39 is made of a high strength material that is impermeable to water. For example, it can consist of polyethylene or polyurethane and polyimide with a thickness of approximately 25 ⁇ m.
  • the cover film 39 is provided with a metal pad 41, which is used for shielding.
  • the chamber 40 can also contain components belonging to these amplifiers 32 and 36, for example resistors and capacitors, for each row of the amplifiers 32 and 36. which are indicated in the figure as a common component for the sake of simplicity and denoted by 52 and 56 respectively.
  • These components 52 and 56 are each provided with a multiplexer 44 or 45, the output signals of which can be dissipated with a common signal line 48, arranged on a circuit board, not specified.
  • the signal line 48 can preferably be designed as a multiple cable, which contains both the power supply for all components of the hydrophone and the addressing.
  • the ultrasound coupling medium 38 merely has the task of preventing an air layer between the receiving element 10 and the cover film 39.
  • a layer of a water-containing gel or silicone grease, for example, is suitable as the ultrasound coupling medium 38, the thickness of which generally does not substantially exceed a few J.Lm.
  • the base body 2 of the receiving elements 10 is provided as a cover film for the chamber 40.
  • the adhesive layer 6 also forms an electrical coupling medium for the electrode 5, which is attached to the carrier 16.
  • the metallic cover 4 also serves as a ground electrode for the receiving elements 10.

Claims (14)

1. Hydrophone comportant un corps de base piézoélectrique plat (2), qui contient un ensemble disposé linéairement d'éléments récepteurs (10) comportant des zones (3) actives du point de vue piézoélectrique, auxquelles sont associées, sur les deux faces planes, des rangées respectives d'électrodes métalliques (4, 5) et de conducteurs électriques de raccordement (14, 15), remarquable par les caractéristiques d'agencement suivantes :
les électrodes (5) situées sur l'une des faces planes du corps de base (2) sont disposées sur une surface de revêtement plane (15) d'un support mécanique (16) et sont accouplées de façon capacitive, au moyen d'une couche adhésive générale (6) non électriquement conductrice et utilisée comme milieu de couplage électrique, aux zones actives associées (3) du corps de base (2), et
des amplificateurs respectifs (32, 36) sont associés aux éléments récepteurs (10),
ces amplificateurs (32, 36) sont fixés par au moins des conducteurs d'alimentation (11, 26 ou 12, 27) possédant au moins approximativement des longueurs identiques, sur au moins l'une des surfaces latérales (17 ou 18) du support (16), et les zones superficielles, voisines du bord (22 ou 23) délimité par la surface de revêtement (15) et les surfaces latérales (17, 18), de cette surface de revêtement (15) et de ces surfaces latérales (17 ou 18) du support (16) comportent, au voisinage des conducteurs de raccordement (11 ou 12), des rainures respectives (24 ou 25) perpendiculaires au bord (22, 23), et
au moins une partie de la surface située à l'intérieur de la rainure (24, 25) comporte une métallisation qui est reliée aussi bien à l'électrode (5) de l'élément récepteur associé (10) qu'à l'amplificateur associé (32 ou 36).
2. Hydrophone suivant la revendication 1, caractérisé par le fait qu'il est prévu plusieurs modules possédant le même pas de réseau que celui des éléments récepteurs (10), dont le début et l'extrémité sont agencés de telle sorte que le pas du réseau reste conservé dans le cas d'une disposition en série de ces modules.
3. Hydrophone selon la revendication 1 ou 2, caractérisé par le fait qu'il est prévu des amplificateurs hybrides (32).
4. Hydrophone selon la revendication 3, caractérisé par le fait qu'il est prévu des transistors MOS FET à double grille en tant qu'éléments actifs des amplificateurs hybrides (32, 36).
5. Hydrophone suivant la revendication 4, caractérisé par le fait que les résistances de dérivation des transistors MOS FET à double grille sont disposés sur un substrat commun (33 ou 37), qui est fixé sur une surface latérale (17 ou 18) du support (16).
6. Hydrophone suivant la revendication 5, caractérisé par le fait qu'il est prévu un substrat à couches minces.
7. Hydrophone suivant l'une des revendications 1 à 6, caractérisé par le fait qu'il est prévu un élément de renforcement dur possédant une impédance acoustique nettement supérieure à l'impédance acoustique du milieu véhiculant le son, en tant que support (16), dont la surface tournée à l'opposé du corps de base (2) porte un absorbeur (46).
8. Hydrophone suivant l'une des revendications 1 à 7, caractérisé par le fait qu'il est prévu comme support (16) un organe de renforcement mou possédant au moins approximativement la même impédance acoustique que le milieu véhiculant le son.
9. Hydrophone suivant l'une des revendications 1 à 48, caractérisé en ce qu'il est disposé dans une chambre (40), qui contient également un système d'alimentation en courant ainsi qu'au moins un multiplexeur (44, 45).
10. Hydrophone suivant la revendication 9, caractérisé par le fait que la face avant de la chambre (40) est fermée par une feuille de revêtement (39), dont l'épaisseur est nettement inférieure à la longueur d'onde du champ ultrasonore devant être mesuré.
11. Hydrophone suivant la revendication 10, caractérisé par le fait qu'un milieu (38) de couplage des ultrasons est prévu entre la feuille de revêtement (39) et les éléments récepteurs (10).
12. Hydrophone suivant la revendication 10 ou 11, caractérisé par le fait que la feuille de revêtement (39) comporte, sur sa face plane tournée à l'opposé des éléments récepteurs (10), une couche protectrice (41) réalisée en un matériau électriquement conducteur.
13. Hydrophone suivant la revendication 10, caractérisé par le fait que le corps de base (2) des éléments récepteurs (10) est prévu en tant que feuille de revêtement.
14. Hydrophone suivant la revendication 13, caractérisé par le fait que le corps de base (1) situé sur la face plane tournée vers le support (16) est munie d'une couche métallique formant une électrode (4) et prévue en tant qu'électrode de masse commune pour les éléments récepteurs (10).
EP85106107A 1984-05-30 1985-05-17 Hydrophone Expired EP0166180B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3420273 1984-05-30
DE3420273 1984-05-30

Publications (2)

Publication Number Publication Date
EP0166180A1 EP0166180A1 (fr) 1986-01-02
EP0166180B1 true EP0166180B1 (fr) 1989-02-01

Family

ID=6237290

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85106107A Expired EP0166180B1 (fr) 1984-05-30 1985-05-17 Hydrophone

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US (1) US4755708A (fr)
EP (1) EP0166180B1 (fr)
JP (1) JPS60261293A (fr)
DE (1) DE3568093D1 (fr)

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2635247B1 (fr) * 1988-08-05 1990-10-19 Thomson Csf Transducteur piezoelectrique pour generer des ondes de volume
FR2664119B1 (fr) * 1990-06-29 1993-06-11 Inst Francais Du Petrole Systeme integre de reception d'ondes acoustiques de grande longueur.
GB9126082D0 (en) * 1991-12-06 1992-02-05 Nat Res Dev Acoustic non-destructive testing
US5329496A (en) * 1992-10-16 1994-07-12 Duke University Two-dimensional array ultrasonic transducers
US5311095A (en) * 1992-05-14 1994-05-10 Duke University Ultrasonic transducer array
US5744898A (en) * 1992-05-14 1998-04-28 Duke University Ultrasound transducer array with transmitter/receiver integrated circuitry
EP0772891A4 (fr) * 1994-07-22 1999-11-03 Loral Infrared & Imaging Syst Reseau pour imagerie ultrasonore
GB9502999D0 (en) * 1995-02-16 1995-04-05 Precision Acoustics Ltd Ultrasound detector
US5855049A (en) * 1996-10-28 1999-01-05 Microsound Systems, Inc. Method of producing an ultrasound transducer
US10330810B2 (en) 2014-11-17 2019-06-25 Halliburton Energy Services, Inc. Hydrophone having no internal leads
CN107876919A (zh) * 2017-11-09 2018-04-06 北京海纳川汽车部件股份有限公司 活塞的制造方法以及活塞
EP4034307A4 (fr) * 2019-09-23 2023-10-11 Fujifilm Sonosite, Inc. Hydrophone à membrane pour ultrasons haute fréquence et procédé de fabrication
CN113405645B (zh) * 2021-06-08 2022-09-27 哈尔滨工程大学 一种基于活塞的耐静水压光纤水听器

Family Cites Families (10)

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Publication number Priority date Publication date Assignee Title
GB1530783A (en) * 1976-01-30 1978-11-01 Emi Ltd Ultra-sonic pickup device
JPS5825450B2 (ja) * 1978-11-15 1983-05-27 三菱油化株式会社 生体用トランスジユ−サ
DE3069001D1 (en) * 1979-05-16 1984-09-27 Toray Industries Piezoelectric vibration transducer
IT1162336B (it) * 1979-06-22 1987-03-25 Consiglio Nazionale Ricerche Procedimento per la realizzazione di trasduttori ultraacustici a cortina di linee o a matrice di punti e trasduttori ottenuti
FR2485857B1 (fr) * 1980-06-25 1986-05-02 Commissariat Energie Atomique Sonde ultrasonore multi-elements et son procede de fabrication
US4517665A (en) * 1980-11-24 1985-05-14 The United States Of America As Represented By The Department Of Health And Human Services Acoustically transparent hydrophone probe
DE3149732A1 (de) * 1981-12-15 1983-07-21 Siemens AG, 1000 Berlin und 8000 München Ultraschallwandleranordnung
FR2531298B1 (fr) * 1982-07-30 1986-06-27 Thomson Csf Transducteur du type demi-onde a element actif en polymere piezoelectrique
DE3246661A1 (de) * 1982-12-16 1984-06-20 Siemens AG, 1000 Berlin und 8000 München Verfahren zum herstellen von um eine aussenkante fuehrenden elektrischen anschlussleitungen
US4555953A (en) * 1984-04-16 1985-12-03 Paolo Dario Composite, multifunctional tactile sensor

Also Published As

Publication number Publication date
JPS60261293A (ja) 1985-12-24
DE3568093D1 (en) 1989-03-09
US4755708A (en) 1988-07-05
EP0166180A1 (fr) 1986-01-02

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