EP0166180B1 - Hydrophone - Google Patents

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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
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EP
European Patent Office
Prior art keywords
hydrophone according
receiving elements
carrier
base body
hydrophone
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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
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EP85106107A
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German (de)
French (fr)
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EP0166180A1 (en
Inventor
Bernd Dr. Granz
Bertram Sachs
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Siemens AG
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Siemens AG
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    • 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.

Description

Die Erfindung bezieht sich auf ein Hydrophon mit einem flachen piezoelektrischen Grundkörper, der . eine lineare Anordnung von Empfangselementen mit piezoelektrisch aktiven Bereichen enthält, denen an beiden Flachseiten jeweils ein Muster von metallischen Elektroden und elektrischen Anschlußleitern zugeordnet ist. Der elektrisch aktive Bereich des Grundkörpers ist in Richtung der Dicke der Folie polarisiert und hat in der Ebene der Flachseiten des Grundkörpers nur eine sehr geringe Ausdehnung.The invention relates to a hydrophone with a flat piezoelectric base body. contains a linear arrangement of receiving elements with piezoelectrically active areas, to each of which a pattern of metallic electrodes and electrical connecting conductors is assigned on both flat sides. 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.

Solche Miniatur-Hydrophone dienen bekanntlich zum Vermessen von Ultraschallfeldern in einem schalltragenden Medium. Als Grundkörper kann eine Membrane aus Polyvinylidenfluorid PVDF oder Copolymeren von Vinylidenfluorid mit Tetrafluorethylen oder auch mit Trifluorethylen mit einer Dicke von beispielsweise etwa 25 J.Lm vorgesehen sein, die als Membrane zwischen zwei Ringen aus Metall aufgespannt sein kann. In ihrem Mittelpunkt befindet sich der piezoelektrisch aktive Bereich, der mit Elektroden versehen ist und ein Empfangselement bildet. Die Folie kann ferner am Ende eines Koaxialkabels aufgespannt und ihr piezoelektrisch aktiver Bereich mit einer Ausdehnung von etwa 1 mm etwa auf der Spitze einer Nadel angeordnet sein. Mit dieser Nadelausführung erhält man eine Empfindlichkeit von etwa 6,3 x 10-8 V/Pa (Ultrasonics, Sept. 1981, 213 bis 216). Die Abtastung von Ultraschallfeldern größerer Ausdehnung mit einer derartigen Sonde, die nur ein einziges Empfangselement enthält, erfordert jedoch einen verhältnismäßig großen zeitlichen Aufwand.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. With this embodiment needle to obtain a sensitivity of about 6.3 x 10 8 V / Pa (Ultrasonics, Sept. 1981, 213 to 216). However, the scanning of ultrasonic fields of a larger extent with such a probe, which contains only a single receiving element, requires a relatively large amount of time.

Man hat eine als Grundkörper vorgesehene Folie aus Polyvinylidenfluorid PVDF auch schon mit einer linearen Anordnung einer größeren Anzahl von piezoelektrisch aktiven Bereichen versehen, denen ein Muster von Elektroden und Zuleitungen zugeordnet ist, die im allgemeinen aus Metall bestehen. Diese Muster sind an beiden Flachseiten der Folie durch Aufdampfen befestigt. Die Empfangselemente haben einen Durchmesser von etwa 2 mm und ihre Kapazität beträgt etwa 8 pF. Ein Vorverstärker ist an ein Kabel mit etwa 30 cm Länge angeschlossen. Mit dieser Anordnung erhält man eine Empfindlichkeit von etwa 3,2 - 10-6 V/Pa (J. Accoust. Soc. Am., Vol. 61,.Suppi. No. 1, Spring 1977, Seiten S 17 und S 18).A film made of polyvinylidene fluoride PVDF, which is provided as the base body, has also already been provided with a linear arrangement of a larger number of piezoelectrically active regions, to which a pattern of electrodes and supply lines is assigned, which generally consist of metal. These patterns are attached to both flat sides of the film by vapor deposition. 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 .

Die Erfindung beruht nun auf der Erkenntnis, daß die Ausdehnung der Empfangselemente nicht beliebig begrenzt werden kann, weil metallische Elektroden an der Polymer-Folie schlecht haften. Außerdem kann die Empfindlichkeit nur erhöht werden, wenn jedem Empfangselement ein elektronisches Verstärkerelement, vorzugsweise ein Feldeffekttransistor, zugeordnet ist, das in unmittelbarer Nähe des Empfangselements angeordnet sein muß. Ein Anschluß eines verhältnismäßig weit entfernt liegenden Verstärkers belastet durch die Leitungskapazität CL das Empfangselement und führt mit einer Kapazität CE des Empfangselementes und einer Empfängerspannung UE zu einer verminderten Spannung U gemäß

Figure imgb0001
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. In addition, 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
Figure imgb0001

Ein Koaxialkabel hat beispielsweise eine Leitungskapazität von etwa 1 pF/cm, so daß man beispielsweise bei einer 30 cm Leitung eine Reduktion der Empfängerspannung auf CE/30 pF erhält. Ist dagegen am Ausgang des Verstärkers die Impedanz bereits gewandelt, kann man dann eine Leitung zu weiteren Teilen des Verstärkers führen. Ist eine größere Anzahl von Empfangselementen dicht nebeneinander angeordnet, so muß man auch die zugehörigen Verstärker im annähernd gleichen Rastermaß anordnen.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.

Der Erfindung liegt somit die Aufgabe zugrunde, dieses bekannte Miniatur-Hydrophon zu verbessern, insbesondere soll ein Hydrophon angegeben werden, mit dem auch unbekannte Ultraschallfelder größerer Ausdehnung in kurzer Zeit und in einfacher Weise gemessen werden können. Ferner soll die Brauchbarkeit und die Empfindlichkeit erhöht werden.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.

In einer bekannten Ausführungsform einer Ultraschallwandler-Anordnung ist eine lineare Anordnung von Wandlerelementen in der Ausführungsform als Querschwinger an der Schmalseite eines gemeinsamen, flachen Substrats befestigt. Einander gegenüberliegende, parallel zur Polarisationsachse verlaufenden Oberflächen der Wandlerelemente sind jeweils mit einer Metallisierung versehen. Die freien Stirnflächen der Wandlerelemente dienen zum Abstrahlen des Ultraschalls. Die Wandlerelemente sind durch Schnitte senkrecht zur Stirnfläche hergestellt und elektrisch gegeneinander isoliert. Die Flachseiten des Substrats sind mit Elektroden in Dünnfilmtechnik versehen und mit den Metallisierungen der Wandlerelementen elektrisch leitend verbunden. Auf einer der Flachseiten des Substrats ist die erforderliche Elektronik in Dünnfilmtechnik angeordnet (GB-A-2 052 918).In a known embodiment of an ultrasonic transducer arrangement, 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).

Es ist ferner ein Ultraschallaufnehmner für zweidimensionale Bildabtastung bekannt mit diskreten Ultraschallwandlern, denen jeweils eine flexible Leiterplatte zugeordnet ist, die mit einem integrierten Schaltkreis versehen ist. In dieser Ausführungsform haben die Anschlußleiter ungleiche Längen (GB-A-1 530 783).Furthermore, 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. In this embodiment, the leads are of unequal lengths (GB-A-1 530 783).

Eine weitere bekannte Ultraschallwandleranordnung mit mehreren Wandlerelementen zur Aufnahme von Ultraschallschwingungen aus einem schalltragenden Medium enthält als Grundkörper eine Folie aus Polyvinylidenfluorid PVDF. Dieser Grundkörper ist an einer seiner Flachseiten in vorbestimmten piezoelektrisch wirksamen Bereichen, die jeweils eines der Wandlerelemente bilden, jeweils mit einer Elektrode aus elektrisch leitendem Material versehen. Die Folie ist nur in diesen Bereichen in Richtung ihrer Dicke polarisiert und mit ihren Elektroden der einen Flachseite auf einem Grundkörper angeordnet. Diese monolithische Ausführungsform einer Ultraschallwandleranordnung bildet ein breitbandiges Empfangsarray mit hoher Empfindlichkeit (DE-A-31 49 732).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).

Die Dicke der Elektroden, die vorzugsweise auf einer Deckfläche des Trägerkörpers befestigt, beispielsweise aufgedampft, werden, wird im allgemeinen wenige µm nicht wesentlich überschreiten und vorzugsweise wesentlich weniger als 1 JJ.m betragen. Somit dürfen auch die zugeordneten elektrischen Verbindungsleiter diese Dicke nicht wesentlich überschreiten. Sie können auf verhältnismäßig einfache Weise im gleichen Arbeitsgang mit den Elektroden, beispielsweise in einem photolithographischen Prozeß, hergestellt werden. Es ist jedoch schwierig, diese Verbindungsleiter um eine Kante des Trägerkörpers herumzuführen, wenn diese Leiter mit elektrischen Elementen verbunden werden sollen, die an einem Oberflächenteil des Trägers angeordnet sind, der mit der Dreckfläche eine Kante bildet. Man kann in diesem Falle die der Kante benachbarten Oberflächenbereiche der Deckfläche und der Seitenfläche mit einer Nut versehen, die senkrecht zur Kante gerichtet ist. Innerhalb dieser Nuten wird wenigstens ein Teil der Oberfläche mit einer Metallisierung versehen, mit deren Hilfe die Leitungsverbindung zwischen den Elektroden und den erwähnten elektrischen Elementen beispielsweise durch einen Lötkontakt hergestellt wird (DE-A-32 46 661).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 μm and preferably be substantially less than 1 JJ.m. Thus, 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. However, it is difficult to route these connecting conductors around an edge of the carrier body if these conductors are to be connected to electrical elements which are arranged on a surface part of the carrier which forms an edge with the dirt surface. In this case, 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).

Die Erfindung macht Gebrauch von diesen bekannten Gestaltungsmerkmalen einer Ultraschallwandleranordnung und sie besteht in den kennzeichnenden Merkmalen des Anspruchs 1. Die Ausdehnung der Empfangselemente in der Ebene der Flachseiten des Grundkörpers beträgt im allgemeinen weniger als 1 mm und ihr Abstand ist begrenzt auf nicht wesentlich mehr als ein zehntel Millimeter. Da auch die Ausdehnung der zugeordneten Verstärker, vorzugsweise Hybridverstärker, diese Maße nicht wesentlich überschreitet, ergibt sich daraus auch ein Rastermaß der linearen Anordnung von weniger als 1 mm. Dieses Hydrophon hat eine Empfindlichkeit von mindestens 10-5 V/Pa. Zum Vermessen eines Ultraschallfeldes ist nur noch eine Verschiebung in einer Richtung quer zur linearen Anordnung der Empfangselemente erforderlich. In einer besonderen Ausführungsform des Hydrophons beträgt der Abstand des ersten und letzten Empfangselements vom Anfang bzw. dem Ende des Trägerkörpers nur jeweils etwa die Hälfte des Abstands der Empfangselemente untereinander. Man kann somit eine größere Anzahl von Modulen in der linearen Ausdehnungsrichtung der Empfangselemente zu einer gemeinsamen Baueinheit mit dem gleichen Rastermaß hintereinander anordnen, mit der auch Ultraschallfelder größerer Ausdehnung in kurzer Zeit vermessen werden können.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. In a special embodiment of the hydrophone, 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.

Weitere vorteilhafte Ausführungsform des Hydrophons ergeben sich aus den Unteransprüchen.Further advantageous embodiments of the hydrophone result from the subclaims.

Zur weiteren Erläuterung der Erfindung wird auf die Zeichnung Bezug genommen, in der verschiedene Ausführungsformen eines Hydrophons nach der Erfindung schematisch veranschaulicht sind.

  • In Figur 1 ist ein Teil einer Seitenansicht des Hydrophons dargestellt.
  • Figur 2 zeigt einen Teil des Hydrophons in perspektivischer Darstellung.
  • In Figur 3 ist die Anodnung eines Hydrophons mit den zugeordneten elektrischen Elementen in einer gemeinsamen Kammer in einem Schnitt veranschaulicht.
  • Figur 4 zeigt eine besondere Ausführungsformen der Empfangselemente und ihre Ankopplung an die Abdeckfolie der Kammer.
To further explain the invention, reference is made to the drawing, in which various embodiments of a hydrophone according to the invention are illustrated schematically.
  • FIG. 1 shows part of a side view of the hydrophone.
  • Figure 2 shows a part of the hydrophone in perspective.
  • FIG. 3 illustrates the arrangement of a hydrophone with the associated electrical elements in a common chamber in a section.
  • Figure 4 shows a special embodiment of the receiving elements and their coupling to the cover film of the chamber.

In der Ausführungsform nach Figur 1 wird ein Empfangselement 10 gebildet aus dem in der Figur gestrichelt angedeuteten piezoelektrisch aktiven Bereich 3 eines Grundkörpers 2, dem an seiner oberen Flachseite eine Elektrode 4 und an seiner unteren Flachseite eine Elektrode 5 zugeordnet ist,'die auf einem Trägerkörper 16 befestigt ist. Die Elektrode 5 ist mittels einer elektrisch nicht leitenden Haftschicht 6 mit einer hohen Dielektrizitätskonstante an den piezoelektrisch aktiven Bereich 3 des Grundkörpers 2 kapazitiv angekoppelt. Die untere Elektrode 5 ist mit einem elektrischen Anschlußleiter 11 versehen. Von dem in einer linearen Anordnung der Empfangselemente 10 benachbarten Empfangselement ist in der Figur ein Anschlußleiter 12 sichtbar. Die Deckfläche 15 des Trägers 16 wird seitlich begrenzt von zwei schrägen Seitenflächen 17 bzw. 18, die mit der Deckfläche 15 jeweils eine Kante 22 bzw. 23 bilden. Diese Kanten 22 und 23 sind im Bereich der Anschlußleiter 11 bzw. 12 jeweils mit einer Nut 24 bzw. 25 versehen, die senkrecht zu der Kante 22 bzw. 23 gerichtet sind und deren innere Oberflächen jeweils mindestens teilweise mit einer in der Figur nicht dargestellten Metallisierung versehen sind. Die Metallisierung in der Nut 24 dient beispielsweise als elektrische Verbindung, vorzugsweise zum Verlöten, eines Anschlußleiters 26 für einen dem Empfangselement 10 zugeordneten Verstärker 32, der auf einem Substrat 33 angeordnet ist. Von dem in der Figur nicht dargestellten benachbarten Empfangselement ist ein zugeordneter Verbindungsleiter 27 und ein Verstärker 36, der in gleicher Weise auf einem Substrat 37 angeordnet ist, in der Figur sichtbar.In the embodiment according to FIG. 1, 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. These 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).

Der Grundkörper 2 des Empfangselements 10 besteht aus einer Folie eines Polymers, vorzugsweise Polyvinylidenfluorid PVDF, oder auch einem Copolymer von Vinylidenfluorid mit Tetrafluorethylen oder mit Trifluorethylen, mit einer Dicke von beispielsweise etwa 25 µm, die in ihrem piezoelektrisch aktiven Bereich 3 in Richtung ihrer Dicke polarisiert ist. Die zugeordneten Elektroden 4 und 5 bestehen aus Metall, dessen Dicke vorzugsweise wenige JJ.m nicht überschreitet und insbesondere wesentlich geringer als 1 4m sein kann. Vorzugsweise geeignet ist Chrom/Silber oder auch Chrom/Gold, bei dem die Chromschicht mit einer Dicke von beispielsweise etwa 20 nm als Haftvermittler dient, auf dem dann eine Silberschicht von etwa 0,2 f.Lm abgeschieden wird. Die Elektrode 5 kann zweckmäßig in einem gemeinsamen Arbeitsgang mit ihrem zugeordneten Anschlußleiter 11 auf den Trägerkörper 16 aufgebracht. insbesondere aufgedampft oder aufgesputtert, sein. Die Elektrode 5 ist mit Hilfe der Haftschicht 6, die aus einem elektrisch isolierenden Material mit hoher Dielektrizitätskonstante besteht und vorzugsweise eine Kleber- oder Kittschicht sein kann, mittelbar am Grundkörper 2 befestigt. Der Träger 16, das sogenannte Backing, kann vorzugsweise aus einem Material mit hoher akustischer Impedanz bestehen. Zu dieser Ausführungsform als sogenanntes Hard-Backing ist beispielsweise Keramik, vorzugsweise Aluminiumoxid A1203, geeignet, dessen Schallimpedanz etwa 40 x 106 kg/m2s beträgt. Ferner ist auch Glas oder Quarz mit einer Schallimpedanz von 14 x 106 kg/m2s geeignet. Als Träger 16 kann auch ein weiches Backing vorgesehen sein, das den Ultraschall selbst absorbiert und beispielsweise aus Gummi bestehen kann. Ein empfangenes Ultraschallsignal wird dann in einem Frequenzbereich von etwa 1 bis wenigstens 10 MHz im Wandlerelement 10 von der unteren Flachseite des aktiven Bereichs 3 zur Elektrode 5 kapazitiv übergekoppelt und über die Anschlußleiter 11 und 26 dem zugeordneten Verstärker 32 zugeführt.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 μm, 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. For this embodiment as so-called 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.

Als Verstärker 32 sind vorzugsweise Hybridverstärker geeignet, die auf einem Substrat 33, vorzugsweise einem Dünnfilmsubstrat, angeordnet sind. Diese Hybridverstärker haben einen heterogenen Aufbau. Die Widerstände können vorzugsweise in Dünnfilmtechnik aufgebaut sein, während die zugehörigen Transistoren als Transistorchips aufgeklebt und ihre elektrisch leitenden Verbindungen gebondet werden.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.

Das Empfangselement 10 ist über ein Ultraschallkoppelmedium 38 an eine Abdeckfolie 39 angekoppelt, die beispielsweise aus einem Polymer bestehen kann und als Abschlußwand der Frontseite einer Kammer dienen kann, in der die dargestellte Baueinheit angeordnet ist.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.

Entsprechend der perspektivischen Darstellung nach Figur 2 ist für eine Vielzahl von Empfangselementen 10, die in der Figur gestrichelt angedeutet sind, an der oberen Flachseite des gemeinsamen Grundkörpers 2 eine für alle Empfangselemente 10 gemeinsame Elektrode 4 vorgesehen. Der Grundkörper 2 mit der Haftschicht 6 ist zur Verdeutlichung in einem gewissen Abstand von den unteren Elektroden 5 dargestellt, die in der linearen Ausdehnungsrichtung eines in der Figur nicht näher bezeichneten Moduls mit beispielsweise 16 Empfangselementen 10 hintereinander angeordnet sind. Beispielsweise erhält man mit einer Länge 1 = 0,8 mm und einer Breite b = 0,7 mm sowie einem Abstand a = 0,1 mm der Elektroden 5 ein Rastermaß der Empfangselemente 10 von 0,8 mm, so daß die gesamte Länge L des Moduls etwa 12 mm beträgt. Damit erhält man bei einer Frequenz von beispielsweise 2 MHz eine Kapazität CE der Empfangselemente 10 von etwa -1,6 pF.According to the perspective illustration according to FIG. 2, 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. For example, with a length 1 = 0.8 mm and a width b = 0.7 mm and a distance a = 0.1 mm of the electrodes 5, 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.

In einer besonders vorteilhaften Ausführungsform des Hydrophons können die den Empfangselementen 10 zugeordneten Verstärker 32 bzw. 36 jeweils abwechselnd auf einer der Seitenflächen 17 bzw. 18 des Trägers 16 angeordnet sein. Die Länge der elektrischen Leitungsverbindung zwischen der Elektrode 5 und dem zugeordneten Verstärker 32, die aus den Anschlußleitern 11 und 26 gebildet wird, die mit Hilfe der Metallisierung innerhalb der Nut 22 miteinander verbunden sind, ist sehr kurz und kann beispielsweise nur etwa 1 mm betragen und ist außerdem für alle Empfangselemente 10 gleich. Die Empfindlichkeit des Systems aus Empfangselement 10 und Verstärker 32 bzw. 36 ist somit homogen und sehr hoch. Mit der geringen Eigenkapazität der Hybridverstärker von beispielsweise ewa 2 pF und einer hohen Eingangsimpedanz von beispielsweise etwa 100 kΩ sowie einer etwa 20 fachen Verstärkung und einer geringen Kanalbreite von etwa 1,6 mm sowie einer hohen Bandbreite von etwa 15 MHz und geringem Rauschen von etwa 8 nV/VHz erhält man bei einem Hydrophon mit 16 Empfangswandlern 10 und einem 25 f.Lm dicken Grundkörper 2 eine Empfindlichkeit von etwa 10-5 V/Pa.In a particularly advantageous embodiment of the hydrophone, 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. With the low internal capacitance of the hybrid amplifiers of, for example, ewa 2 pF and a high input impedance of, for example, approximately 100 kΩ as well as approximately 20 times amplification and a small channel width of approximately 1.6 mm, as well as a high bandwidth of approximately 15 MHz and low noise of approximately 8 With a hydrophone with 16 receiving transducers 10 and a base body 2 25 f.Lm thick, nV / VHz gives a sensitivity of about 10- 5 V / Pa.

Die Verstärker 32 sind mit Hilfe metallisierter Bereiche 42 an der Oberfläche des Substrats 33 mit elektrischen Signalleitungen 43 versehen, die zu weiteren Bauelementen der Verstärker 32 führen können.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.

In der Ausführungsform nach Figur 3 ist ein Modul mit einer Vielzahl von Empfangselementen 10 in einer Kammer 40 angeordnet, die an ihrer Stirnseite durch die Abdeckfolie 39 abgeschlossen ist, die über das Ultraschallkoppelmedium 38 an das Empfangselement 10 angekoppelt ist, das auf dem Träger 16 angeordnet ist. Dieser Träger 16 besteht aus einem harten Backing, an dessen dem Empfangselement 10 abgewandten Ende ein Absorber 46 vorgesehen ist, der beispielsweise aus Epoxidharz bestehen kann, das mit Zuschlägen versehen ist, die beispielsweise aus Aluminiumoxidpulver bestehen können. Das Ende des Trägers 16 ist spitz ausgebildet, damit der von der Grenzfläche zwischen Absorber 46 und Träger 16 reflektierte Anteil einer in den Träger 16 eingedrungenen Ultraschallwelle vermindert wird. Die Wände der Kammer 40 bestehen im allgemeinen aus Metall. Die Abdeckfolie 39 besteht aus einem Material mit hoher Festigkeit, das wasserundurchlässig ist. Sie kann beispielsweise aus Polyethylen oder Polyurethan sowie Polyimid mit einer Dicke von etwa 25 µm bestehen.In the embodiment according to FIG. 3, 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 μm.

In einer besonders vorteilhaften Ausführungsform des Hydrophons ist die Abdeckfolie 39 mit einer Metallauflage 41 versehen, die zur Abschirmung dient. Außer den Empfangselementen 10 sowie deren zugeordneten Verstärkern 32 und 36, deren elektrische Verbindungsleiter zur Vereinfachung nicht dargestellt sind, kann die Kammer 40 für jede Reihe der Verstärker 32 und 36 noch zu diesen Verstärkern 32 und 36 gehörende Bauelemente, beispielsweise Widerstände und Kondensatoren, enthalten, die in der Figur zur Vereinfachung als gemeinsames Bauteil angedeutet und mit 52 bzw. 56 bezeichnet sind. Diese Bauteile 52 und 56 sind jeweils mit einem für alle Verstärker 32 bzw. 36 gemeinsamen Multiplexer 44 bzw. 45, deren Ausgangssignale mit einer gemeinsamen Signalleitung 48 abgeführt werden können, auf einer nicht näher bezeichneten Leiterplatte angeordnet. Die Signalleitung 48 kann vorzugsweise als Mehrfachkabel ausgeführt sein, das sowohl die Stromversorgung für alle Bauteile des Hydrophons als auch die Adressierung enthält.In a particularly advantageous embodiment of the hydrophone, the cover film 39 is provided with a metal pad 41, which is used for shielding. In addition to the receiving elements 10 and their associated amplifiers 32 and 36, the electrical connection conductors of which are not shown for the sake of simplicity, 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.

Das Ultraschallkoppelmedium 38 hat lediglich die Aufgabe, eine Luftschicht zwischen dem Empfangselement 10 und der Abdeckfolie 39 zu verhindern. Als Ultraschallkoppelmedium 38 ist beispielsweise eine Schicht aus einem wasserhaltigen Gel oder aus Silikonfett geeignet, deren Dicke im allgemeinen wenige J.Lm nicht wesentlich überschreitet und beispielsweise 5 J.Lm betragen kann.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.

In der Ausführungsform eines Hydrophons nach Figur 4 ist der Grundkörper 2 der Empfangselemente 10 als Abdeckfolie für die Kammer 40 vorgesehen. Die Haftschicht 6 bildet zugleich ein elektrisches Koppelmedium für die Elektrode 5, die auf dem Träger 16 befestigt ist. In dieser Ausführungsform dient die metallische Abdeckung 4 zugleich als Masseelektrode für die Empfangselemente 10.In the embodiment of a hydrophone according to FIG. 4, 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. In this embodiment, the metallic cover 4 also serves as a ground electrode for the receiving elements 10.

Claims (14)

1 - Hydrophone having a flat piezoelectric base body (2) which contains a linear arrangement of receiving elements (10) with piezoelectrically active regions (3), with which on both flat sides, in each case, there is associated a series of metallic electrodes (4, 5) and electric supply leads (14, 15) (sic), characterised by the following features of configuration :
The electrodes (5) of one of the flat sides of the base body (2) are arranged on a flat cover surface (15) of a mechanical carrier (16) and are coupled by means of a common, electrically non-conductive adhesive layer (6), serving as an electric coupling medium, capacitively to the associated active regions (3) of the base body (2) ;
and associated with the receiving elements (10) there is, in each case, an amplifier (32, 36) ;
these amplifiers (32, 36) are secured, with feed lines (11, 26 or 12, 27) of at least approximately the same length, to at least one of the side faces (17 or 18) of the carrier (16) and the surface areas of the cover surface (15) and the side faces (17 or 18) of the carrier (16), adjacent to the edge (22 or 23) between cover surface (15) and side faces (17, 18), are provided in the area of the supply leads (11 or 12), in each case, with a groove (24 or 25) extending in a manner perpendicular to the edge (22, 23) and
at least one part of the surface inside the groove (24, 25) is provided with a metallic coating which is connected both with the electrode (5) of the associated receiving element (10) and with the associated amplifier (32 or 36).
2. Hydrophone according to claim 1, characterised in that several modules are provided, having the same grid dimension as the receiving elements (10), the start and end of the receiving elements (10) of which being configured such that with a series arrangement of these modules the grid dimension is preserved.
3. Hydrophone according to claim 1 or 2, characterised in that hybrid amplifiers (32) are provided.
4. Hydrophone according to claim 3, characterised in that dual gate-MOS FEts are provided as active elements of the hybrid amplifiers (32, 36).
5. Hydrophone according to claim 4, characterised in that the dual gate-MOS FETs are arranged with their bleed resistors on a common substrate (33 or 37) which is secured to a side face (17 or 18) of the carrier (16).
6. Hydrophone according to claim 5, characterised in that a thin film substrate is provided.
7. Hydrophone according to one of the claims 1 to 6, characterised in that a hard backing having substantially higher acoustic impedance than the acoustic impedance of the sound-carrying medium is provided as a carrier (16) upon the surface of which, remote from the base body (2), there is arranged an absorber (46).
8. Hydrophone according to one of the claims 1 to 7, characterised in that a soft backing having at least approximately the same acoustic impedance as the sound-carrying medium is provided as a carrier (16).
9. Hydrophone according to one of the claims 1 to 8, characterised by the arrangement in a chamber (40) which also contains a current supply as well as at least one multiplexer (44, 45).
10. Hydrophone according to claim 9, characterised in that the front side of the chamber (40) is sealed by a cover foil (39), the thickness of which is substantially less than the wavelength of the ultrasound field to be measured.
11. Hydrophone according to claim 10, characterised in that provided between the cover foil (39) and the receiving elements (10) there is an ultra-sound coupling medium (38).
12. Hydrophone according to claim 10 or 11, characterised in that the cover foil (39), on its flat side remote from the receiving elements (10), is provided with a protective layer (41) of electrically conductive material.
13. Hydrophone according to claim 10, characterised in that the base body (2) of the receiving elements (10) is provided as a cover foil.
14. Hydrophone according to claim 13, characterised in that the base body (2), on the flat side remote from the carrier (16), is provided with a metal layer which forms an electrode (4) and is provided as a common earth electrode for the receiving elements (10).
EP85106107A 1984-05-30 1985-05-17 Hydrophone Expired EP0166180B1 (en)

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 (en) 1986-01-02
EP0166180B1 true EP0166180B1 (en) 1989-02-01

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

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

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2635247B1 (en) * 1988-08-05 1990-10-19 Thomson Csf PIEZOELECTRIC TRANSDUCER FOR GENERATING VOLUME WAVES
FR2664119B1 (en) * 1990-06-29 1993-06-11 Inst Francais Du Petrole INTEGRATED SYSTEM FOR RECEIVING LONG LENGTH ACOUSTIC WAVES.
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 (en) * 1994-07-22 1999-11-03 Loral Infrared & Imaging Syst Ultrasound imaging array
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
CA2964080C (en) 2014-11-17 2019-10-01 Halliburton Energy Services, Inc. Hydrophone having no internal leads
CN107876919A (en) * 2017-11-09 2018-04-06 北京海纳川汽车部件股份有限公司 The manufacture method and piston of piston
JP2022551418A (en) * 2019-09-23 2022-12-09 フジフィルム ソノサイト インコーポレイテッド MEMBRANE-TYPE HYDROPHONE FOR HIGH FREQUENCY ULTRASOUND AND METHOD FOR MANUFACTURING HYDROPHONE
CN113405645B (en) * 2021-06-08 2022-09-27 哈尔滨工程大学 Hydrostatic pressure resistant optical fiber hydrophone based on piston

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1530783A (en) * 1976-01-30 1978-11-01 Emi Ltd Ultra-sonic pickup device
JPS5825450B2 (en) * 1978-11-15 1983-05-27 三菱油化株式会社 Biological transducer
DE3069001D1 (en) * 1979-05-16 1984-09-27 Toray Industries Piezoelectric vibration transducer
IT1162336B (en) * 1979-06-22 1987-03-25 Consiglio Nazionale Ricerche PROCEDURE FOR THE CREATION OF ULTRA ACOUSTIC TRANSDUCERS WITH CURTAIN OF LINES OR WITH A MATRIX OF POINTS AND TRANSDUCERS OBTAINED
FR2485857B1 (en) * 1980-06-25 1986-05-02 Commissariat Energie Atomique MULTI-ELEMENT ULTRASONIC PROBE AND MANUFACTURING METHOD THEREOF
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 (en) * 1981-12-15 1983-07-21 Siemens AG, 1000 Berlin und 8000 München Ultrasonic transducer arrangement
FR2531298B1 (en) * 1982-07-30 1986-06-27 Thomson Csf HALF-WAVE TYPE TRANSDUCER WITH PIEZOELECTRIC POLYMER ELEMENT
DE3246661A1 (en) * 1982-12-16 1984-06-20 Siemens AG, 1000 Berlin und 8000 München Method for producing electrical connecting leads leading around an outer edge
US4555953A (en) * 1984-04-16 1985-12-03 Paolo Dario Composite, multifunctional tactile sensor

Also Published As

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

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