WO2009086805A1 - Ultrasonic transducer for generating asymmetric sound fields - Google Patents

Ultrasonic transducer for generating asymmetric sound fields Download PDF

Info

Publication number
WO2009086805A1
WO2009086805A1 PCT/DE2008/002140 DE2008002140W WO2009086805A1 WO 2009086805 A1 WO2009086805 A1 WO 2009086805A1 DE 2008002140 W DE2008002140 W DE 2008002140W WO 2009086805 A1 WO2009086805 A1 WO 2009086805A1
Authority
WO
WIPO (PCT)
Prior art keywords
membrane
transducer element
ultrasonic transducer
ultrasonic
transducer
Prior art date
Application number
PCT/DE2008/002140
Other languages
German (de)
French (fr)
Inventor
Christian Degel
Daniel Schmitt
Original Assignee
Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
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 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. filed Critical Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority to EP08869632A priority Critical patent/EP2229242B1/en
Priority to DE112008003772T priority patent/DE112008003772A5/en
Priority to AT08869632T priority patent/ATE509708T1/en
Publication of WO2009086805A1 publication Critical patent/WO2009086805A1/en

Links

Classifications

    • 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
    • G10K9/00—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers
    • G10K9/12—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated
    • G10K9/122—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated using piezoelectric driving means

Definitions

  • the present invention relates to an ultrasonic transducer for generating asymmetric sound fields, in particular for applications in gaseous media, comprising a housing having an elongate membrane and a plate-shaped transducer element of an electrostrictive material, through which the membrane can be excited to oscillate in the ultrasonic range.
  • Ultrasonic transducers which generate asymmetrical sound fields are used, inter alia, in the field of spatial surveillance, for example as parking sensors in motor vehicles.
  • Ultrasonic transducers for use in gaseous media, in particular in air, generally generate sound in the range between 20 and 400 kHz.
  • conventional ultrasound transducers have a circular diaphragm which, by means of a transducer element made of an electrostrictive material, is attached thereto
  • Ultrasonic transducers with a circular diaphragm or aperture generally generate symmetrical sound fields. However, for many applications, particularly where the ultrasonic transducers are located near a ceiling, floor or wall, asymmetric sound fields are desired which have a greater extent along the axis perpendicular to the main propagation direction than along the perpendicular axis. This relates, for example, to ultrasound transducers which are used in parking aid systems of motor vehicles and are intended to have a broader sound radiation in the horizontal with respect to the vertical.
  • An asymmetrical sound radiation can be achieved by a correspondingly asymmetrical design of the membrane of the ultrasonic transducer.
  • Under the membrane here is the thinned region of the transducer to understand, which is excited by the transducer element to ultrasonic vibrations.
  • the shape of the membrane thus also corresponds to the shape of the aperture of the ultrasonic transducer.
  • a membrane may be a separate component which is held in a housing or also formed by a thin portion of an otherwise solid component.
  • an ultrasonic transducer for generating an asymmetric sound field which comprises a housing with an elongated membrane and a arranged on one side of a main surface of the membrane plate-shaped transducer element of an electro has strict material through which the membrane is excitable to vibrations in the ultrasonic range.
  • the membrane formed integrally with the housing in this case has an elongated shape which is obtained by corresponding cutouts or holes in the material block forming the housing.
  • the plate-shaped transducer element is glued centrally on the inner surface of the membrane.
  • DE 19512417 C2 describes a piezoelectric ultrasonic transducer for transit time measurements, which can also be used for space monitoring.
  • the ultrasonic transducer has a plurality of mutually equally spaced, piezoelectric lamellae, which is connected at their respective narrow sides with a continuous one-piece cover plate. Due to the elongated cover plate a correspondingly asymmetric sound radiation is achieved.
  • the construction of this converter is complex.
  • the object of the present invention is to provide a simply constructed ultrasonic transducer for generating asymmetric sound fields, which can be used in gaseous media and allows a large ratio of the opening angle of the sound radiation.
  • the proposed ultrasonic transducer has, in a known manner, a housing with an elongated membrane and a plate-shaped transducer element made of an electrostrictive material, arranged on one side of a main surface of the membrane, through which the membrane oscillates in the
  • Ultrasonic range is excitable.
  • electrodes are attached to the transducer element in a known manner, via which the transducer element can be excited to oscillate or can be detected via the electrical voltage changes on the transducer element which are caused by the reception of ultrasonic waves.
  • the transducer element here preferably consists of a piezoelectric material, for example a piezoelectric ceramic.
  • the proposed ultrasonic transducer is characterized in that a gap is formed between the diaphragm and the transducer element and the diaphragm is mechanically coupled to the transducer element only via its edge.
  • the mechanical coupling can in this case be realized via a stepped intermediate element between the transducer element and the membrane.
  • the proposed ultrasonic transducer has only on one side of the transducer element a membrane in order to achieve the desired sound radiation. Due to the elongated shape of the membrane this forms an elongated aperture for the sound radiation of the
  • Ultrasonic transducer so that the ultrasonic transducer generates a correspondingly asymmetric sound field.
  • the membrane is driven by the plate-shaped transducer element, which transmits the vibration only at the edge and is not fully connected to the membrane, as is the case in the prior art in this field.
  • This embodiment also achieves a lever effect which amplifies the deflection of the membrane and thus enables increased oscillation amplitudes and an increased range of the ultrasonic radiation.
  • By coupling the membrane only over its edge with the transducer element can be with appropriate asymmetry of the membrane, i. a corresponding unequal ratio of length to the width of the membrane, readily generate vibration modes that allow a ratio of the opening angle of the sound radiation of 1: 3 or above.
  • the membrane has a rectangular basic shape.
  • the corners of this rectangular basic shape can also be rounded due to the production.
  • Such an ultrasonic transducer can be produced inexpensively and allows a larger ratio of the opening angles of the sound radiation in two mutually perpendicular planes than is possible with the previously known ultrasonic transducers for the present applications.
  • the transducer element is not operated in the thickness mode, but in a lateral vibration mode, for example.
  • the 3-1 mode It is only essential for the design of the membrane that a geometric axis is substantially longer than the other axis, whereby the elongated shape and thus the asymmetrical sound radiation is achieved.
  • the membrane is mechanically coupled to the transducer element over a region of the housing.
  • the transducer element is preferably inserted into a peripheral recess in a wall region of the housing.
  • the recess is arranged, for example, on the rear side opposite the membrane of the housing, that a gap between the membrane and the transducer element is present.
  • the membrane may in this case be formed integrally with the housing in a known manner.
  • an ultrasonic transducer With such an ultrasonic transducer, a three-dimensional space can be illuminated with ultrasound to detect obstacles or objects.
  • the ultrasonic transducer allows a range of several meters and can be due to the asymmetric sound field in the vicinity of reflective surfaces, such as walls, floor or ceiling, use.
  • the ultrasonic transducer consists of only a few components and can be inexpensively produce.
  • Such an ultrasound transducer can be used, for example, for distance detection, access control or navigation assistance, for example in conjunction with a parking assistance system, although this is of course not an exhaustive list.
  • Fig. 1 shows an example of the structure of
  • Fig. 2 is a schematic representation of
  • Fig. 3 is a plan view of the proposed ultrasonic transducer according to an embodiment in a schematic representation.
  • the ultrasonic transducer shown schematically in section in FIG. 1 has a housing 1 in which a membrane 2 is formed by appropriate shaping.
  • the housing 1 also has a Auf strictlyung for receiving a piezoceramic plate as a plate-shaped transducer element 3.
  • the transducer element 3 can in this case be glued into this recess shown in the figure.
  • Housing and membrane are integrally formed of the same material, in the present example of aluminum.
  • the plate-shaped transducer element 3 can be formed, for example, from PZT 5H, a piezoceramic.
  • the electrodes mounted on both sides of the plate-shaped transducer element 3 are not shown in the figures. The person skilled in the art is familiar with the arrangement of such electrodes on piezoelectric transducer elements.
  • the ultrasonic transducer shown in Figure 1 for example, a graded total thickness of about 2mm, a recognizable in the figure width of about 10mm and a length of about 35mm exhibit.
  • Transducer element 3 and the membrane 2 formed air gap is about 1.5 mm.
  • the width of the membrane is about 8mm.
  • the plate-shaped transducer element 3 is not connected directly to the membrane 2. Rather, the mechanical coupling of this transducer element 3 takes place with the membrane 2 only via the housing 1 with the edge of the membrane 2. This construction allows others
  • Vibration modes as in full-surface bonding of the transducer element with the membrane so that by suitable elongated geometry of the membrane with a simple Effort significantly more asymmetrical sound fields (ie, with a larger ratio of the opening angle) can be generated, as with the construction according to the prior art described above.
  • Figure 2 shows schematically the vibration transmission between the transducer element 3 and the membrane 2.
  • a leverage is achieved by the coupling via the housing 1 and the edge of the membrane 2, which advantageously leads to a vibration amplification.
  • the membrane 2 carries out larger oscillation amplitudes than the exciting transducer element 3.
  • FIG. 3 shows a plan view of such an ultrasonic transducer in a schematic representation.
  • the almost rectangular shape of the membrane 2 and the underlying transducer element 3 are indicated by dashed lines.
  • the length of the membrane 2 can be scaled almost arbitrarily in order to generate correspondingly different asymmetries of the sound fields.

Abstract

The invention relates to an ultrasonic transducer for generating asymmetric sound fields. Said ultrasonic transducer comprises a housing (1) that encompasses an elongate diaphragm (2) and a plate-shaped transducer element (3) which is arranged on one side of a main surface of the diaphragm (2), is made of an electrostrictive material, and allows the diaphragm (2) to be excited to generate oscillations in the ultrasonic range. A gap is formed between the diaphragm (2) and the transducer element (3), the diaphragm (2) being coupled to the transducer element (3) exclusively along the edge thereof. Such an ultrasonic transducer makes it possible to generate asymmetric sound fields which have an aperture ratio of 1:3 or more.

Description

Ultraschallwandler zur Erzeugung asymmetrischer Ultrasonic transducer for generating asymmetric
Schallfeldersound fields
Technisches AnwendungsgebietTechnical application
Die vorliegende Erfindung betrifft einen Ultraschallwandler zur Erzeugung asymmetrischer Schallfelder, insbesondere für Anwendungen in gasförmigen Medien, der ein Gehäuse mit einer länglich ausgebildeten Membran und einem plattenförmigen Wandlerelement aus einem elektrostriktiven Material aufweist, durch das die Membran zu Schwingungen im Ultraschallbereich anregbar ist.The present invention relates to an ultrasonic transducer for generating asymmetric sound fields, in particular for applications in gaseous media, comprising a housing having an elongate membrane and a plate-shaped transducer element of an electrostrictive material, through which the membrane can be excited to oscillate in the ultrasonic range.
Ultraschallwandler, die asymmetrische Schallfelder erzeugen, sind unter anderem im Bereich der räumlichen Überwachung im Einsatz, bspw. als Parksensoren bei Kraftfahrzeugen .Ultrasonic transducers which generate asymmetrical sound fields are used, inter alia, in the field of spatial surveillance, for example as parking sensors in motor vehicles.
Stand der Technik Ultraschallwandler für den Einsatz in gasförmigen Medien, insbesondere in Luft, erzeugen in der Regel Schall im Bereich zwischen 20 und 400 kHz. Herkömmliche Ultraschallwandler weisen hierzu eine kreisrunde Membran auf, die durch ein daran angebrachtes Wandler- element aus einem elektrostriktiven Material zuPRIOR ART Ultrasonic transducers for use in gaseous media, in particular in air, generally generate sound in the range between 20 and 400 kHz. For this purpose, conventional ultrasound transducers have a circular diaphragm which, by means of a transducer element made of an electrostrictive material, is attached thereto
Schwingungen im Ultraschallbereich angeregt werden kann. In gleicher Weise können auf die Membran auftreffende Ultraschallwellen, die die Membran in Schwingungen versetzen, durch das Wandlerelement in elektrische Signale gewandelt werden. Ultraschallwandler mit kreisförmiger Membran bzw. Apertur erzeugen in der Regel symmetrische Schallfelder. Für viele Anwendungen, insbesondere bei einer Anordnung der Ultraschallwandler nahe einer Decke, eines Bodens oder einer Wand, sind jedoch asymmetrische Schallfelder erwünscht, die in der Ebene senkrecht zur Hauptausbreitungsrichtung entlang einer Achse eine größere Ausdehnung als entlang der dazu senkrechten Achse aufweisen. Dies betrifft bspw. Ultraschallwandler, die in Parkhilfesystemen von Kraftfahrzeugen eingesetzt werden und eine breitere Schallabstrahlung in der Horizontalen gegenüber der Vertikalen aufweisen sollen.Vibrations in the ultrasonic range can be excited. In the same way, ultrasonic waves impinging on the membrane, which cause the membrane to vibrate, can be converted into electrical signals by the transducer element. Ultrasonic transducers with a circular diaphragm or aperture generally generate symmetrical sound fields. However, for many applications, particularly where the ultrasonic transducers are located near a ceiling, floor or wall, asymmetric sound fields are desired which have a greater extent along the axis perpendicular to the main propagation direction than along the perpendicular axis. This relates, for example, to ultrasound transducers which are used in parking aid systems of motor vehicles and are intended to have a broader sound radiation in the horizontal with respect to the vertical.
Eine asymmetrische Schallabstrahlung lässt sich durch eine entsprechend asymmetrische Ausgestaltung der Membran des Ultraschallwandlers erzielen. Unter der Membran ist hierbei der abgedünnte Bereich des Wandlers zu verstehen, der durch das Wandlerelement zu Ultraschallschwingungen angeregt wird. Die Form der Membran entspricht damit auch der Form der Apertur des Ultraschallwandlers. Eine Membran kann ein gesondertes Bauteil darstellen, das in einem Gehäuse gehalten wird oder auch durch einen dünnen Bereich eines ansonsten massiveren Bauteils gebildet sein.An asymmetrical sound radiation can be achieved by a correspondingly asymmetrical design of the membrane of the ultrasonic transducer. Under the membrane here is the thinned region of the transducer to understand, which is excited by the transducer element to ultrasonic vibrations. The shape of the membrane thus also corresponds to the shape of the aperture of the ultrasonic transducer. A membrane may be a separate component which is held in a housing or also formed by a thin portion of an otherwise solid component.
So ist bspw. aus der DE 10 2006 050 037 Al ein Ultraschallwandler zur Erzeugung eines asymmetrischen Schallfeldes bekannt, der ein Gehäuse mit einer länglich ausgebildeten Membran und einem auf einer Seite einer Hauptfläche der Membran angeordneten plattenförmigen Wandlerelement aus einem elektro- striktiven Material aufweist, durch das die Membran zu Schwingungen im Ultraschallbereich anregbar ist. Die integral mit dem Gehäuse gebildete Membran weist hierbei eine längliche Form auf, die durch entsprechende Ausfräsungen oder Bohrungen in dem das Gehäuse bildenden Materialblock erhalten wird. Das plattenförmige Wandlerelement ist zentral auf die innere Fläche der Membran aufgeklebt. Mit einem derartigen Ultraschallwandler lassen sich jedoch bisher nur asymmetrische Schallfelder erzeugen, bei denen das Verhältnis der Öffnungswinkel der Schallabstrahlung in zwei senkrecht aufeinander stehenden Ebenen maximal ca. 1:2 beträgt.For example, from DE 10 2006 050 037 Al an ultrasonic transducer for generating an asymmetric sound field is known, which comprises a housing with an elongated membrane and a arranged on one side of a main surface of the membrane plate-shaped transducer element of an electro has strict material through which the membrane is excitable to vibrations in the ultrasonic range. The membrane formed integrally with the housing in this case has an elongated shape which is obtained by corresponding cutouts or holes in the material block forming the housing. The plate-shaped transducer element is glued centrally on the inner surface of the membrane. With such an ultrasonic transducer, however, so far only asymmetric sound fields can be generated in which the ratio of the opening angle of the sound radiation in two mutually perpendicular planes is at most approximately 1: 2.
Die DE 19512417 C2 beschreibt einen piezoelektrischen Ultraschallwandler für Laufzeitmessungen, der auch zur Raumüberwachung eingesetzt werden kann. Der Ultraschallwandler weist mehrere, voneinander gleich beabstandete, piezoelektrische Lamellen auf , die an ihren jeweiligen Schmalseiten mit einer durchgängigen einstückigen Deckplatte verbunden ist. Durch die länglich ausgebildete Deckplatte wird eine entsprechend asymmetrische Schallabstrahlung erreicht. Die Konstruktion dieses Wandlers ist jedoch -aufwändig.DE 19512417 C2 describes a piezoelectric ultrasonic transducer for transit time measurements, which can also be used for space monitoring. The ultrasonic transducer has a plurality of mutually equally spaced, piezoelectric lamellae, which is connected at their respective narrow sides with a continuous one-piece cover plate. Due to the elongated cover plate a correspondingly asymmetric sound radiation is achieved. However, the construction of this converter is complex.
Ausgehend von diesem Stand der Technik besteht die Aufgabe der vorliegenden Erfindung darin, einen einfach aufgebauten Ultraschallwandler zur Erzeugung asymmetrischer Schallfelder anzugeben, der sich in gasförmigen Medien einsetzen lässt und ein großes Verhältnis der Öffnungswinkel der Schallabstrahlung ermöglicht. Darstellung der ErfindungBased on this prior art, the object of the present invention is to provide a simply constructed ultrasonic transducer for generating asymmetric sound fields, which can be used in gaseous media and allows a large ratio of the opening angle of the sound radiation. Presentation of the invention
Die Aufgabe wird mit dem Ultraschallwandler gemäß Patentanspruch 1 gelöst. Vorteilhafte Ausgestaltungen des Ultraschallwandlers sind Gegenstand der abhängigen Patentansprüche oder lassen sich der nachfolgenden Beschreibung sowie dem Ausführungsbeispiel entnehmen.The object is achieved with the ultrasonic transducer according to claim 1. Advantageous embodiments of the ultrasonic transducer are the subject of the dependent claims or can be found in the following description and the embodiment.
Der vorgeschlagene Ultraschallwandler weist in bekannter Weise ein Gehäuse mit einer länglich ausgebildeten Membran und einem auf einer Seite einer Hauptfläche der Membran angeordneten plattenförmigen Wandlerelement aus einem elektrostriktiven Material auf, durch das die Membran zu Schwingungen imThe proposed ultrasonic transducer has, in a known manner, a housing with an elongated membrane and a plate-shaped transducer element made of an electrostrictive material, arranged on one side of a main surface of the membrane, through which the membrane oscillates in the
Ultraschallbereich anregbar ist. An dem Wandlerelement sind hierzu in bekannter Weise Elektroden angebracht, über die das Wandlerelement zu Schwingungen anregbar ist oder über die elektrische Spannungsänderungen am Wandlerelement, die durch den Empfang von Ultraschallwellen verursacht werden, detektiert werden können. Das Wandlerelement besteht hierbei vorzugsweise aus einem piezoelektrischen Material, bspw. einer piezoelektrischen Keramik.Ultrasonic range is excitable. For this purpose, electrodes are attached to the transducer element in a known manner, via which the transducer element can be excited to oscillate or can be detected via the electrical voltage changes on the transducer element which are caused by the reception of ultrasonic waves. The transducer element here preferably consists of a piezoelectric material, for example a piezoelectric ceramic.
Der vorgeschlagene Ultraschallwandler zeichnet sich dadurch aus, dass zwischen der Membran und dem Wandlerelement ein Spalt ausgebildet und die Membran nur über ihren Rand mechanisch mit dem Wandlerelement gekoppelt ist. Die mechanische Kopplung kann hierbei über ein auch abgestuftes Zwischenelement zwischen dem Wandlerelement und der Membran realisiert sein. Der vorgeschlagenen Ultraschallwandler weist nur auf einer Seite des Wandlerelementes eine Membran auf, um die gewünschte Schallabstrahlung zu erreichen. Durch die längliche Form der Membran bildet diese eine längliche Apertur für die Schallabstrahlung desThe proposed ultrasonic transducer is characterized in that a gap is formed between the diaphragm and the transducer element and the diaphragm is mechanically coupled to the transducer element only via its edge. The mechanical coupling can in this case be realized via a stepped intermediate element between the transducer element and the membrane. The proposed ultrasonic transducer has only on one side of the transducer element a membrane in order to achieve the desired sound radiation. Due to the elongated shape of the membrane this forms an elongated aperture for the sound radiation of the
Ultraschallwandlers, so dass der Ultraschallwandler ein entsprechend asymmetrisches Schallfeld erzeugt. Die Membran wird durch das plattenförmige Wandlerelement angetrieben, das die Schwingung nur am Rand überträgt und nicht vollflächig mit der Membran verbunden ist, wie dies bei dem bisherigen Stand der Technik auf diesem Gebiet der Fall ist. Durch diese Ausgestaltung wird auch eine Hebelwirkung erzielt, die die Auslenkung der Membran verstärkt und somit erhöhte Schwingungs- amplituden und eine erhöhte Reichweite der Ultraschallabstrahlung ermöglicht. Durch die Kopplung der Membran nur über ihren Rand mit dem Wandlerelement lassen sich bei entsprechender Asymmetrie der Membran, d.h. einem entsprechend ungleichen Verhältnis von Länge zur Breite der Membran, ohne Weiteres Schwingungsmoden erzeugen, die ein Verhältnis der Öffnungswinkel der Schallabstrahlung von 1:3 oder darüber ermöglichen.Ultrasonic transducer, so that the ultrasonic transducer generates a correspondingly asymmetric sound field. The membrane is driven by the plate-shaped transducer element, which transmits the vibration only at the edge and is not fully connected to the membrane, as is the case in the prior art in this field. This embodiment also achieves a lever effect which amplifies the deflection of the membrane and thus enables increased oscillation amplitudes and an increased range of the ultrasonic radiation. By coupling the membrane only over its edge with the transducer element can be with appropriate asymmetry of the membrane, i. a corresponding unequal ratio of length to the width of the membrane, readily generate vibration modes that allow a ratio of the opening angle of the sound radiation of 1: 3 or above.
Besonders vorteilhaft weist die Membran eine rechteckige Grundform auf. Die Ecken dieser rechteckigen Grundform können dabei selbstverständlich auch herstellungsbedingt abgerundet sein. Ein derartiger Ultraschallwandler lässt sich kostengünstig herstellen und ermöglicht ein größeres Verhältnis der Öffnungs- winkel der Schallabstrahlung in zwei zueinander senkrechten Ebenen als dies mit den bisher bekannten Ultraschallwandlern für die vorliegenden Anwendungen möglich ist. Vorzugsweise wird dabei das Wandlerelement nicht in der Dickenmode betrieben, sondern in einer lateralen Schwingungsmode, bspw. der 3-1 Mode. Wesentlich für die Ausgestaltung der Membran ist lediglich, dass eine geometrische Achse wesentlich länger als die andere Achse ist, wodurch die längliche Form und damit die asymmetrische Schallabstrahlung erreicht wird.Particularly advantageously, the membrane has a rectangular basic shape. Of course, the corners of this rectangular basic shape can also be rounded due to the production. Such an ultrasonic transducer can be produced inexpensively and allows a larger ratio of the opening angles of the sound radiation in two mutually perpendicular planes than is possible with the previously known ultrasonic transducers for the present applications. Preferably, the transducer element is not operated in the thickness mode, but in a lateral vibration mode, for example. The 3-1 mode. It is only essential for the design of the membrane that a geometric axis is substantially longer than the other axis, whereby the elongated shape and thus the asymmetrical sound radiation is achieved.
In einer bevorzugten Ausgestaltung ist die Membran über einen Bereich des Gehäuses mechanisch mit dem Wandlerelement gekoppelt. Das Wandlerelement ist hierzu vorzugsweise in eine umlaufende Ausnehmung in einem Wandbereich des Gehäuses eingesetzt. Die Ausnehmung ist so angeordnet, bspw. an der der Membran gegenüber liegenden Rückseite des Gehäuses, dass ein Spalt zwischen der Membran und dem Wandlerelement vorhanden ist. Die Membran kann hierbei in bekannter Weise einstückig mit dem Gehäuse gebildet sein. Durch die mechanische Kopplung über einen Teil des Gehäuses mit dem Rand der Membran wird auch eine Hebelwirkung erzielt, durch die die Auslenkung der Membran gegenüber der Schwingung des Wandlerelementes verstärkt wird.In a preferred embodiment, the membrane is mechanically coupled to the transducer element over a region of the housing. For this purpose, the transducer element is preferably inserted into a peripheral recess in a wall region of the housing. The recess is arranged, for example, on the rear side opposite the membrane of the housing, that a gap between the membrane and the transducer element is present. The membrane may in this case be formed integrally with the housing in a known manner. The mechanical coupling over a part of the housing with the edge of the membrane also achieves a lever effect by which the deflection of the diaphragm relative to the vibration of the transducer element is enhanced.
Mit einem derartigen Ultraschallwandler lässt sich ein dreidimensionaler Raum mit Ultraschall ausleuchten, um Hindernisse oder Objekte zu erkennen. Der Ultraschallwandler ermöglicht eine Reichweite von mehreren Metern und lässt sich insbesondere aufgrund des asymmetrischen Schallfeldes auch in der Nähe von reflektierenden Flächen, wie Wänden, Boden oder Decke, einsetzen. Der Ultraschallwandler besteht aus nur wenigen Bauteilen und lässt sich kostengünstig herstellen. Ein derartiger Ultraschallwandler lässt sich bspw. für die Abstandserkennung, die Zugangskontrolle oder die Navigationsunterstützung, bspw. in Verbindung mit einem Parkassistenzsystem, einsetzen, wobei dies selbstverständlich keine abschließende Aufzählung ist.With such an ultrasonic transducer, a three-dimensional space can be illuminated with ultrasound to detect obstacles or objects. The ultrasonic transducer allows a range of several meters and can be due to the asymmetric sound field in the vicinity of reflective surfaces, such as walls, floor or ceiling, use. The ultrasonic transducer consists of only a few components and can be inexpensively produce. Such an ultrasound transducer can be used, for example, for distance detection, access control or navigation assistance, for example in conjunction with a parking assistance system, although this is of course not an exhaustive list.
Kurze Beschreibung der Zeichnungen Der vorgeschlagene Ultraschallwandler wird nachfolgend anhand eines Ausführungsbeispiels in Verbindung mit den Zeichnungen nochmals kurz erläutert, Hierbei zeigen:BRIEF DESCRIPTION OF THE DRAWINGS The proposed ultrasonic transducer will be briefly explained again below with reference to an exemplary embodiment in conjunction with the drawings, in which:
Fig. 1 ein Beispiel für den Aufbau desFig. 1 shows an example of the structure of
Ultraschallwandlers im Schnitt in schematischer Darstellung;Ultrasonic transducer in section in a schematic representation;
Fig. 2 eine schematische Darstellung derFig. 2 is a schematic representation of
Schwingungsübertragung zwischen Membran und Wandlerelement bei dem Ultraschallwandler der Fig. 1; undVibration transmission between the diaphragm and transducer element in the ultrasonic transducer of Fig. 1; and
Fig. 3 eine Draufsicht auf den vorgeschlagenen Ultraschallwandler gemäß einem Ausführungsbeispiel in schematischer Darstellung.Fig. 3 is a plan view of the proposed ultrasonic transducer according to an embodiment in a schematic representation.
Wege zur Ausführung der ErfindungWays to carry out the invention
Der in Figur 1 schematisch in Schnitt dargestellte Ultraschallwandler weist ein Gehäuse 1 auf, in dem durch entsprechende Ausformung eine Membran 2 ausgebildet ist. Das Gehäuse 1 weist weiterhin eine Aufnehmung zur Aufnahme einer piezokeramischen Platte als plattenförmiges Wandlerelement 3 auf. Das Wandlerelement 3 kann hierbei in diese in der Figur dargestellte Ausnehmung eingeklebt sein. Gehäuse und Membran sind einstückig aus dem gleichen Material gebildet, im vorliegenden Beispiel aus Aluminium. Das plattenförmige Wandlerelement 3 kann bspw. aus PZT 5H, einer Piezokeramik, gebildet sein. Die beidseitig des plattenförmigen Wandlerelements 3 angebrachten Elektroden sind in den Figuren nicht dargestellt. Dem Fachmann ist die Anordnung derartiger Elektroden an piezoelektrischen Wandlerelementen geläufig.The ultrasonic transducer shown schematically in section in FIG. 1 has a housing 1 in which a membrane 2 is formed by appropriate shaping. The housing 1 also has a Aufnehmung for receiving a piezoceramic plate as a plate-shaped transducer element 3. The transducer element 3 can in this case be glued into this recess shown in the figure. Housing and membrane are integrally formed of the same material, in the present example of aluminum. The plate-shaped transducer element 3 can be formed, for example, from PZT 5H, a piezoceramic. The electrodes mounted on both sides of the plate-shaped transducer element 3 are not shown in the figures. The person skilled in the art is familiar with the arrangement of such electrodes on piezoelectric transducer elements.
Für den Einsatz zur Raumüberwachung, bspw. als Parksensor an Kraftfahrzeugen, kann der in der Figur 1 dargestellte Ultraschallwandler bspw. eine auch abgestufte Gesamtdicke von ca. 2mm, eine in der Figur zu erkennende Breite von ca. 10mm sowie eine Länge von ca. 35mm aufweisen. Der durch diese Konstruktion des Ultraschallwandlers zwischen dem plattenförmigenFor use in space monitoring, for example as a parking sensor on motor vehicles, the ultrasonic transducer shown in Figure 1, for example, a graded total thickness of about 2mm, a recognizable in the figure width of about 10mm and a length of about 35mm exhibit. The by this construction of the ultrasonic transducer between the plate-shaped
Wandlerelement 3 und der Membran 2 gebildete Luftspalt beträgt ca. 1,5mm. Die Breite der Membran beträgt ca. 8mm.Transducer element 3 and the membrane 2 formed air gap is about 1.5 mm. The width of the membrane is about 8mm.
Wie aus der Figur 1 deutlich zu erkennen ist, ist das plattenförmige Wandlerelement 3 nicht direkt mit der Membran 2 verbunden. Vielmehr erfolgt die mechanische Kopplung dieses Wandlerelementes 3 mit der Membran 2 lediglich über das Gehäuse 1 mit dem Rand der Membran 2. Diese Konstruktion ermöglicht andereAs can be seen clearly from FIG. 1, the plate-shaped transducer element 3 is not connected directly to the membrane 2. Rather, the mechanical coupling of this transducer element 3 takes place with the membrane 2 only via the housing 1 with the edge of the membrane 2. This construction allows others
Schwingungsmoden als bei vollflächiger Verklebung des Wandlerelementes mit der Membran, so dass durch geeignete längliche Geometrie der Membran mit einfachem Aufwand deutlich asymmetrischere Schallfelder (d. h. mit größerem Verhältnis der Öffnungswinkel) erzeugt werden können, als mit der Konstruktion gemäß dem eingangs beschriebenen Stand der Technik.Vibration modes as in full-surface bonding of the transducer element with the membrane, so that by suitable elongated geometry of the membrane with a simple Effort significantly more asymmetrical sound fields (ie, with a larger ratio of the opening angle) can be generated, as with the construction according to the prior art described above.
Figur 2 zeigt schematisch die Schwingungsübertragung zwischen dem Wandlerelement 3 und der Membran 2. Wie aus den beiden Teilabbildungen dieser Figur ersichtlich ist, wird durch die Kopplung über das Gehäuse 1 und den Rand der Membran 2 eine Hebelwirkung erreicht, die vorteilhaft zu einer Schwingungsverstärkung führt. Die Membran 2 führt dabei größere Schwingungsamplituden aus als das anregende Wandlerelement 3.Figure 2 shows schematically the vibration transmission between the transducer element 3 and the membrane 2. As can be seen from the two partial figures of this figure, a leverage is achieved by the coupling via the housing 1 and the edge of the membrane 2, which advantageously leads to a vibration amplification. The membrane 2 carries out larger oscillation amplitudes than the exciting transducer element 3.
Figur 3 zeigt schließlich eine Draufsicht auf einen derartigen Ultraschallwandler in schematischer Darstellung. In dieser Draufsicht sind die nahezu rechteckige Form der Membran 2 sowie das darunter liegende Wandlerelement 3 durch gestrichelte Linien angedeutet. Die Länge der Membran 2 lässt sich dabei nahezu beliebig skalieren, um entsprechend unterschiedliche Asymmetrien der Schallfelder zu erzeugen. Finally, FIG. 3 shows a plan view of such an ultrasonic transducer in a schematic representation. In this plan view, the almost rectangular shape of the membrane 2 and the underlying transducer element 3 are indicated by dashed lines. The length of the membrane 2 can be scaled almost arbitrarily in order to generate correspondingly different asymmetries of the sound fields.
Bezugs zeichenlisteReference sign list
Gehäuse Membran Wandlerelement Housing membrane transducer element

Claims

Patentansprüche claims
1. Ultraschallwandler zur Erzeugung asymmetrischer Schallfelder, insbesondere für Anwendungen in gasförmigen Medien, der ein Gehäuse (1) mit einer länglich ausgebildeten Membran (2) und einem auf einer Seite einer Hauptfläche der Membran (2) angeordneten plattenförmigen Wandlerelement (3) aus einem elektrostriktiven Material aufweist, durch das die Membran (2) zu Schwingungen im Ultraschallbereich anregbar ist, dadurch gekennzeichnet, dass zwischen der Membran (2) und dem Wandlerelement (3) ein Spalt ausgebildet und die Membran (2) nur über ihren Rand mechanisch mit dem Wandlerelement (3) gekoppelt ist.1. Ultrasonic transducer for generating asymmetric sound fields, in particular for applications in gaseous media, comprising a housing (1) with an elongated membrane (2) and on one side of a main surface of the membrane (2) arranged plate-shaped transducer element (3) of an electrostrictive Material has, by which the membrane (2) is excitable to oscillations in the ultrasonic range, characterized in that between the membrane (2) and the transducer element (3) formed a gap and the membrane (2) only mechanically over its edge with the transducer element (3) is coupled.
2. Ultraschallwandler nach Anspruch 1, dadurch gekennzeichnet, dass die Membran (2) eine rechteckige Form hat, die auch abgerundete Ecken aufweisen kann.2. Ultrasonic transducer according to claim 1, characterized in that the membrane (2) has a rectangular shape, which may also have rounded corners.
3. Ultraschallwandler nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die Membran (2) über einen Bereich des Gehäuses (1) mechanisch mit dem Wandlerelement (3) gekoppelt ist.3. Ultrasonic transducer according to claim 1 or 2, characterized in that the membrane (2) over a portion of the housing (1) is mechanically coupled to the transducer element (3).
4. Ultraschallwandler nach Anspruch 3, dadurch gekennzeichnet, dass das Wandlerelement (3) in eine umlaufende Ausnehmung in einem Wandbereich des Gehäuses (1) ganz oder teilweise eingesetzt ist.4. Ultrasonic transducer according to claim 3, characterized in that the transducer element (3) in a circumferential Recess in a wall portion of the housing (1) is wholly or partially inserted.
5. Ultraschallwandler nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, dass die mechanische Kopplung zwischen dem Wandlerelement (3) und der Membran (2) so ausgeführt ist, dass Schwingungen des Wandlerelementes (3) über eine Hebelwirkung zu demgegenüber in der Amplitude erhöhten Schwingungen der Membran (2) führen.5. Ultrasonic transducer according to one of claims 1 to 4, characterized in that the mechanical coupling between the transducer element (3) and the membrane (2) is designed so that vibrations of the transducer element (3) via a lever action to the contrary increased in amplitude Vibrations of the membrane (2) lead.
6. Ultraschallwandler nach einem der Ansprüche 1 bis6. Ultrasonic transducer according to one of claims 1 to
5, dadurch gekennzeichnet, das s das Wandlerelement ( 3 ) aus einem piezoelektrischen Material besteht .5, characterized in that s the transducer element (3) consists of a piezoelectric material.
7 . Ultraschallwandler nach einem der Ansprüche 1 bis7. Ultrasonic transducer according to one of claims 1 to
6, dadurch gekennzeichnet, dass das Wandlerelement (3) in einer 3-16, characterized in that the transducer element (3) in a 3-1
Schwingungsmode anregbar ist, vorzugsweise eine Resonanz in Richtung der größten Länge des plattenförmigen Wandlerelementes ausnutzend.Vibration mode is excitable, preferably exploiting a resonance in the direction of the largest length of the plate-shaped transducer element.
8. Ultraschallwandler nach einem der Ansprüche 1 bis8. Ultrasonic transducer according to one of claims 1 to
7, dadurch gekennzeichnet, dass das Gehäuse (1) mit der Membran (2) einstückig und abgestuft ausgebildet ist. 7, characterized in that the housing (1) with the membrane (2) is formed in one piece and stepped.
PCT/DE2008/002140 2008-01-09 2008-12-19 Ultrasonic transducer for generating asymmetric sound fields WO2009086805A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP08869632A EP2229242B1 (en) 2008-01-09 2008-12-19 Ultrasonic transducer for generating asymmetric sound fields
DE112008003772T DE112008003772A5 (en) 2008-01-09 2008-12-19 Ultrasonic transducer for generating asymmetric sound fields
AT08869632T ATE509708T1 (en) 2008-01-09 2008-12-19 ULTRASONIC TRANSDUCER FOR GENERATING ASYMMETRIC SOUND FIELDS

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102008003594 2008-01-09
DE102008003594.7 2008-01-09

Publications (1)

Publication Number Publication Date
WO2009086805A1 true WO2009086805A1 (en) 2009-07-16

Family

ID=40622175

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE2008/002140 WO2009086805A1 (en) 2008-01-09 2008-12-19 Ultrasonic transducer for generating asymmetric sound fields

Country Status (4)

Country Link
EP (1) EP2229242B1 (en)
AT (1) ATE509708T1 (en)
DE (1) DE112008003772A5 (en)
WO (1) WO2009086805A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013117437A1 (en) * 2012-02-09 2013-08-15 Robert Bosch Gmbh Sound transducer
EP2949404A3 (en) * 2014-05-29 2015-12-30 Gill Instruments Limited An electroacoustic transducer
DE112011104192B4 (en) * 2010-12-07 2020-01-02 Continental Automotive Gmbh Electroacoustic transducer arrangement and operating method therefor

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4330747C1 (en) * 1993-09-10 1995-02-16 Siemens Ag Ultrasonic transducer and method for producing it
US6328696B1 (en) * 2000-06-15 2001-12-11 Atl Ultrasound, Inc. Bias charge regulator for capacitive micromachined ultrasonic transducers
EP1282337A2 (en) * 2001-07-30 2003-02-05 Victor Company Of Japan, Ltd. Electroacoustic transducer
DE102006050037A1 (en) * 2006-10-24 2008-04-30 Robert Bosch Gmbh Ultrasonic transducer for motor vehicle, has damping unit for damping vibrations of wall, arranged in diaphragm pot in edge section of diaphragm and connected with edge section and inner side of wall in force-fitting manner

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4330747C1 (en) * 1993-09-10 1995-02-16 Siemens Ag Ultrasonic transducer and method for producing it
US6328696B1 (en) * 2000-06-15 2001-12-11 Atl Ultrasound, Inc. Bias charge regulator for capacitive micromachined ultrasonic transducers
EP1282337A2 (en) * 2001-07-30 2003-02-05 Victor Company Of Japan, Ltd. Electroacoustic transducer
DE102006050037A1 (en) * 2006-10-24 2008-04-30 Robert Bosch Gmbh Ultrasonic transducer for motor vehicle, has damping unit for damping vibrations of wall, arranged in diaphragm pot in edge section of diaphragm and connected with edge section and inner side of wall in force-fitting manner

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE112011104192B4 (en) * 2010-12-07 2020-01-02 Continental Automotive Gmbh Electroacoustic transducer arrangement and operating method therefor
WO2013117437A1 (en) * 2012-02-09 2013-08-15 Robert Bosch Gmbh Sound transducer
EP2949404A3 (en) * 2014-05-29 2015-12-30 Gill Instruments Limited An electroacoustic transducer
US9807513B2 (en) 2014-05-29 2017-10-31 Gill Instruments Limited Electroacoustic transducer

Also Published As

Publication number Publication date
EP2229242A1 (en) 2010-09-22
EP2229242B1 (en) 2011-05-18
DE112008003772A5 (en) 2010-12-09
ATE509708T1 (en) 2011-06-15

Similar Documents

Publication Publication Date Title
EP2559024B1 (en) Method for driving an ultrasound sensor and ultrasound sensor
EP2856206B1 (en) Ultrasound sensor and device and method for measuring a distance between a vehicle and an obstacle
DE102012201884A1 (en) transducer
DE102017008776A1 (en) Method and measuring device for determining a fluid size
DE102009040264A1 (en) Ultrasonic waves producing method for e.g. aircraft, involves causing thickness mode of vibrations between converter and component during activation of converter, and producing ultrasonic waves by thickness mode of vibrations
EP2229242B1 (en) Ultrasonic transducer for generating asymmetric sound fields
EP0308899A2 (en) Ultrasonic transducer with astigmatic transmission-reception characteristics
DE102013107154A1 (en) driving device
EP3244172B1 (en) Ultrasonic transducer with spreader element
EP2031580A1 (en) Ultrasound sensor with a holding element and a membrane, wherein the membrane is embedded into the holding element
EP3039448B1 (en) Sensor arrangement
EP3010653B1 (en) Electroacoustic transducer
DE102017209823A1 (en) ultrasonic sensor
EP3010655A1 (en) Electroacoustic transducer
DE102018006127B4 (en) 1D ultrasonic transducer unit for material detection
EP3807017B1 (en) 1d ultrasonic transducer unit for area monitoring
DE102018005540B4 (en) 1D ultrasonic transducer unit
DE102018006130B3 (en) 1D ultrasonic transducer unit for hazard detection for a vehicle
WO2017005636A1 (en) Ultrasonic sensor device for a motor vehicle, comprising two piezo elements; a driver assistance system; a motor vehicle and a method
DE102019130488B3 (en) Object detection sensor
DE10009129A1 (en) Ultrasonic sensor has pot-shaped vibration element whose floor acts as membrane with at least two disc-shaped piezoelectric transducers attached to membrane and adjacent to each other
DE102017122428B4 (en) Ultrasonic sensor for a motor vehicle
EP3010652A1 (en) Surroundings-sensing system having an ultrasonic transducer, and a motor vehicle having such a surroundings-sensing system
DE202019106292U1 (en) Object detection sensor
DE102016119099B4 (en) Ultrasonic sensor, driver assistance device, motor vehicle and method for operating an ultrasonic sensor

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 08869632

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2008869632

Country of ref document: EP

WWE Wipo information: entry into national phase

Ref document number: 1120080037728

Country of ref document: DE

REF Corresponds to

Ref document number: 112008003772

Country of ref document: DE

Date of ref document: 20101209

Kind code of ref document: P