CN108475501B - Acoustic transducer assembly - Google Patents

Abstract

The invention relates to an acoustic transducer assembly (100) having a plurality of transducer elements (10) connected to a common fixing element (20), wherein each transducer element (10) has at least one A piezoelectric element (15) arranged in operative connection with a carrier element (11), and wherein the carrier element (11) is connected to the fixing element (20), characterized in that the fixing element (20) consists of A material composition with a modulus of elasticity greater than ^350x103 N/ ^mm2 , preferably about ^400x103 N/ ^mm2 , and a density greater than 2.5 g/ ^cm3 .

Description

Sound Transducer Components

current technology

)，该声作用面与布置成与声作用面作用连接的压电元件相关联地用于，使换能器元件可以作为发射元件或接收元件运行。这种声换能器组件尤其作为车辆中的驾驶员辅助系统的组成部分使用，尤其用于车辆相对于例如在泊车过程中有关的物体的距离测量。由上述文献没有得到关于固定面(在该固定面上布置有换能器元件)以及换能器元件的电接触的细节。The invention relates to a sound transducer assembly, such as is known from DE 10 2010 062 990 A1 of the applicant. In known sound transducer assemblies, a plurality of transducer elements, each having at least one piezoelectric element, are arranged for example in parallel at a small distance from each other on the fastening surface or fastening element. The connection between the individual transducer elements and the fastening surface can be realized by a material-bonded connection or by a mechanical connection. The individual, particularly uniformly configured transducer elements each have a carrier element with, for example, a U-shaped cross section, wherein both sides of the carrier element are connected to the fastening surface. In addition, the transducer element has an acoustically active surface (schallwirksame

), the acoustically active surface is used in association with the piezoelectric element arranged in operative connection with the acoustically active surface, so that the transducer element can be operated as a transmitting element or as a receiving element. Such acoustic transducer assemblies are used in particular as components of driver assistance systems in vehicles, in particular for distance measurement of the vehicle relative to objects involved, for example during parking procedures. Details regarding the fastening surface on which the transducer element is arranged and the electrical contacting of the transducer element are not available from the above-mentioned documents.

Acoustic transducer assemblies known so far should be constructed as compactly as possible, ie have the smallest possible base area and the smallest possible overall height, especially when used in vehicles, so that they can in particular be free of Problematic installation in the area of the bumper. This creates a desire to use the thinnest possible fastening surfaces or correspondingly thin fastening elements in order to keep the structural height of the sound transducer assembly as low as possible. Likewise, the bottom surface of the fastening surface should be as small as possible in order to also be able to design the sound transducer assembly with the smallest possible cross-section.

For the trouble-free functioning of the transducer elements as transmitting or receiving elements, it is important that the individual transducer elements are as unaffected as possible relative to each other in terms of acoustics or vibrations. Furthermore, it is important that the transducer element be connected to the fastening surface or fastening element as rigidly as possible in the region of the fastening surface or fastening element. It is important here that both the clamped transducer element and the fastening element have natural vibration properties. Here, the natural resonance frequency of the stationary element and its multiples occur. If these natural resonances occur with corresponding amplitude heights in the operating frequency range of the transducer elements, for example in the range of 48 kHz, this leads to significant crosstalk or influence between the individual transducer elements and thus to So-called undesired side lobes and the associated ambiguities occur during object recognition.

Contents of the invention

Proceeding from this prior art, the object of the present invention is to improve the sound transducer assembly in such a way that the influence of the sound transducer elements relative to each other during operation of the sound transducer assembly is as low as possible. This object is solved by the sound transducer assembly according to the invention.

The idea of the invention is that the frequency position and the amplitude of the natural frequency of the fastening element are determined by the geometry of the fastening element, ie by its length, width and thickness and mainly also by the magnitude of the modulus of elasticity and density of the material of the fastening element. As explained at the outset in the paragraph "Prior art", the geometrical dimensions of such fastening elements can only be realized within very small limits, since the sound transducer assembly should have, for example, a maximum size or overall height. Furthermore, the invention makes use of the knowledge that such a fastening element has an optimized natural vibration behavior, that is, if the fastening element is constructed as thick as possible with a high modulus of elasticity and a high density, and at the same time has a desired small length and width, then the fixing element is very rigid. These mentioned recognitions lead to a sound transducer assembly according to the invention in which if the fixing element consists of a modulus of elasticity greater than 350x10 ³ N/mm ² , preferably about 400x 10 ³ N/mm ³ and a material composition with a density greater than 2.5 g/cm ³ , an optimized natural vibration behavior can advantageously be achieved. The precondition for the use of this size or this material is that it is possible to construct a sound transducer assembly in which, if the fixing element has a thickness of at least 5 mm, then between the individual transducer elements The required crosstalk damping between them can be in the range of 20dB or more. In this case, the dimensions (thickness) of the fastening element depend in particular on the choice of the material used for the fastening element.

Advantageous developments of the sound transducer assembly according to the invention are presented below.

In order to be able to achieve the smallest possible overall height of the sound transducer assembly on the one hand, and on the other hand to be able to configure the production of the fastening element as simply as possible and to be able to provide the largest possible surface of the fastening element for the arrangement of the transducers The component, set to, depends on the choice of material used. The fastening element is configured in the form of a plate whose thickness is preferably between 3 mm and 6 mm.

As a material for the fastening element, technical ceramics, in particular aluminum oxide, are used, for example. Such technical ceramics satisfy not only the relatively high density requirements set according to the invention, but also the requirements for a high modulus of elasticity.

Especially for the case where the fastening element is used not only for mechanical fastening or coupling of the transducer element, but also for electrical contacting of the transducer element and/or other electronic components arranged in operative connection with the fastening element, it is advantageous if the The material of the fastening element is metal, in particular aluminum or steel.

If the fastening element is made of technical ceramics, it can be provided that the fastening element is provided with a preferably full-surface metallization at least on the side facing the transducer element in order to achieve the desired electrical conductivity.

In a particularly preferred configuration of this metallization layer, the metallization layer typically has a thickness of between 8 μm and 20 μm and a surface resistance of approximately 0.015Ω.

It should be expressly pointed out here that such a fastening element can not only consist of a single material, for example of technical ceramics or of a metal, but can also consist of layers of the mentioned materials arranged one above the other in the form of a sandwich structure. of each layer. It is therefore conceivable, for example, to provide a sandwich structure of a core made of technical ceramics, which is covered on both sides with metal layers or metal sheets.

It can also be provided that the fastening element is used not only for arranging the transducer element, but simultaneously also for arranging the electronic components in order to be able to evaluate the voltage generated by the piezo element or to be able to electrically actuate the piezo element. In this case, a particularly compact or advantageous arrangement of such components can be achieved on that side of the fastening element facing away from the transducer element.

In this case, it is advantageous for the formation of an electrical contact or connection between two sides of the fastening element if the fastening element is provided with a metallization on the side facing away from the transducer element, and both sides of the fastening element The interconnection is electrically conductive via a further metallization layer arranged on the side of the fastening element, or by means of a connecting element, in particular in the form of a flexible film, or by means of vias arranged in the fastening element. It is also possible to construct the fastening element entirely from metal. In the sense of the invention, a flexible film is understood to be a flexible carrier material to which at least one metallization, for example in the form of a conductor track or the like, is applied.

For the electrical contacting of the transducer element to the fastening element, it is preferably provided that the carrier element, on which the piezoelectric element is fastened, is connected to the fastening element by means of an electrically conductive glue. Consider isotropic and anisotropic conductive adhesives as conductive adhesives. Pay attention to the high adhesive strength of the adhesive connection. The adhesive strength of the adhesive connection is significantly increased by plasma treatment or etching of the adhesive partner (transducer element and fastening element), and thus the clamping of the transducer element is correspondingly fixed. Due to the small layer thickness of the conductive glue and the corresponding filling quantity of the conductive particles, the introduced elasticity is negligible.

As mentioned above, such a transducer element can be operated or controlled not only as a transmitting element but also as a receiving element. Furthermore, it is also known to construct such sound transducer assemblies in such a way that both transmitting and receiving elements are provided. Particularly in the case of an acoustic transducer assembly having not only a transmitting element but also a receiving element, an optimized acoustic decoupling between a transducer element acting as a transmitting element and a transducer element acting as a receiving element can be achieved by Formation: The fastening element has at least two partial elements, namely a first partial element with a groove, in particular with a closed contour, and a second partial element arranged inside the groove forming a gap, wherein the The gap is at least partially filled with an elastomer, and wherein at least two transducer elements are arranged on each of the partial elements. In this case, for example, a transducer element acting as a radiation element is arranged on one subelement, and a transducer element acting as a radiation element is arranged on the other subelement. The mechanical or acoustic decoupling between the two subelements of the fastening element is achieved by means of an elastomer, which preferably has a low modulus of elasticity. In this case, the gap can be filled either completely with the elastomer or only in spots. It can also be provided that the gap filling takes place by means of an injection molding method or a casting method.

If the transducer element has a U-shaped cross-section with a rectangular acoustically active surface, wherein the longitudinal axis of the acoustically active surface of the transducer element acting as a transmitting element is relative to the transducer element acting as a receiving element If the longitudinal axes of the acoustically active surfaces of at least some of the transducer elements are arranged rotated by preferably 90°, an optimization or improvement of the directional characteristics of the emitted waves of the transducer elements acting as emitting elements can be achieved.

As a further damping measure or as a measure for acoustic decoupling it can be provided that intermediate spaces present in the region of the transducer elements and/or between the transducer elements are filled with a damping substance. This damping substance consists, for example, of Fermasil or other, preferably elastic, damping substances.

Supplying or dosing such a damping substance in the region of the transducer element can be relatively difficult to configure when the sound transducer assembly is installed in a housing. Therefore, in order to enable a relatively simple supply of damping substance from a production point of view, it is provided in a preferred embodiment that the fastening element has at least one through-opening outside the fastening region of the fastening to the carrier element for supplying the damping substance to the transducer in the space between the components. The damping substance can thus be supplied from the side of the fastening element facing away from the transducer element by introducing the damping substance, for example via a metering needle, through the through-opening into the intermediate space of the transducer element. In order to simplify or ensure the introduction of the metering needle through the through-opening in the fastening element, the through-opening can have, for example, a beveled introduction edge on the side facing away from the transducer element.

As mentioned above, it is desirable to form a reliable and fixed connection between the fastening element and the transducer element, not only for mechanical reasons but also for electrical conductivity reasons. The adhesive strength of the connection is regarded as an important criterion for this. In order to increase or ensure the adhesive strength, it is advantageous if the fastening element and/or the transducer element is surface-treated, in particular by plasma treatment or by etching.

A preferred field of application of the acoustic transducer assembly described so far is in the field of driver assistance systems in vehicles, in particular for distance measurement of objects. However, the invention should not be limited to such applications. In particular, applications in 3D environment sensors are also conceivable, for example the acoustic transducer assembly is required in the field of robotics, in safety systems such as space monitoring or in ground transport vehicles. In this case, based on the ultrasound, not only the distance of the object/person relative to the sound transducer assembly, but also the angle or position of the object/person relative to the sound transducer can be obtained.

Description of drawings

Further advantages, features and details of the invention emerge from the following description of preferred exemplary embodiments with reference to the drawings.

The accompanying drawings show:

FIG. 1 shows a perspective view of a plurality of transducer elements arranged on a fastening element as part of a sound transducer assembly according to the invention;

2 is a cross-sectional view of an acoustic transducer assembly with three transducer elements in which the transducer elements are in conductive contact with the fixing element using a flexible membrane;

3 is a plan view of a fastening element whose front and rear sides are electrically conductively connected by means of vias;

4 is a cross-section of the fastening element, in which the front and rear sides of the fastening element are electrically connected via metallizations arranged on the sides;

Figure 5 and Figure 6 are top views of fixing elements of different configurations composed of two partial elements;

7 is a plan view of a fastening element configured according to FIG. 5 or 6 and provided with a plurality of transducer elements on the upper side.

Identical elements or elements with the same function are provided with the same reference symbols in the figures.

Detailed ways

1 and 2 show a sound transducer assembly 100 which is used in particular as part of a driver assistance system in a vehicle for measuring distances to objects. In this case, sound transducer assembly 100 is preferably arranged in the region of the front and/or rear bumper of the vehicle.

In the exemplary embodiment shown in FIGS. 1 and 2 , the sound transducer assembly 100 , which is arranged in a housing not shown in the figures, comprises three transducer elements 10 of identical construction. However, the invention is not limited to an arrangement of three transducer elements 10 . Each transducer element 10 has a U-shaped carrier element 11 in cross section, preferably consisting of a metal such as aluminum. The carrier element 11 has a rectangular acoustically active surface 12 which forms a vibrating diaphragm. The surface 12 or membrane is formed by a base body 16 of the carrier element 11 , from which two fastening sides 17 , 18 project. The acoustically active surface 12 is arranged in operative connection with the piezoelectric element 15 . The piezoelectric element 15 is arranged between the fastening sides 17 , 18 on the side of the main body 16 facing the fastening sides 17 , 18 and is connected to the main body 16 by means of an electrically conductive glue 44 . However, according to DE 10 2010 062 990 A1 of the applicant, it is also within the scope of the invention to arrange the piezoelectric element 15 or the plurality of piezoelectric elements 15 at another location on the carrier element 11 .

The three transducer elements 10 provided in the exemplary embodiment according to FIGS. 1 and 2 are arranged parallel to one another at a small distance from one another on a fastening element 20 . Other arrangements of the transducer elements 10 are also possible. The fastening element 20 is configured in the form of a plate 21 with a rectangular cross section. Depending on the material used, the thickness D of the plate 21 is for example between 3 mm and 12 mm. The length of the plate 21 is for example between 40 mm and 50 mm, and the width B is between 25 mm and 35 mm. The material of the plate 21 consists either of metal, preferably aluminum or steel, for example V4A, or of technical ceramics, especially aluminum oxide. Furthermore, the material of the plate 21 has a modulus of elasticity greater than 350×10 ³ N/mm ² , preferably about 400×10 ³ N/mm ² , and a density greater than 2.5 g/cm ³ .

If the material of the plate 21 consists of technical ceramics, it is provided that the upper side of the plate 21 facing the transducer element 10 is preferably provided with a metallization 22 over its entire surface. The adhesion strength of the metallization layer 22 to the plate 21 is in the range of approximately 200 N/mm ² . In order to achieve the desired adhesive strength, the upper side of the plate 21 can be subjected to a surface treatment, in particular a plasma treatment or etching. Metallization layer 22 typically has a thickness between about 8 μm and 20 μm and has a surface resistance in the range of about 0.015Ω. It is preferably provided that the material of the metallization layer 22 contains tungsten.

The two fastening sides 17 , 18 of the carrier element 11 are connected to the upper side of the plate 21 or the fastening element 20 by means of an electrically conductive adhesive 23 . Depending on the desired properties or contact technology, isotropic and anisotropic adhesives 23 are used as adhesives 23 .

In the case where the fastening element 20 consists of metal, for example aluminum or steel, no metallization 22 needs to be provided in order to achieve an electrically conductive surface. Nevertheless, the metallization layer can be provided, for example, to achieve specific electrical conductivity properties or defined surface properties.

Furthermore, within the scope of the invention, the fastening element 20 or the plate 21 is formed not only from a single element, but also from a plurality of elements, which are connected to one another both mechanically and preferably electrically in the form of a sandwich structure.

As can be seen in particular with reference to FIG. 2 , circuit carrier 28 is connected in the form of a conductor plate to fastening element 20 or to plate 21 on the rear side of plate 21 facing away from transducer element 10 . The circuit carrier 28 has an electronic circuit (not shown in detail) with circuit components and/or electronic components 30 , which can be seen in FIG. 2 in the form of an ASIC. The circuit carrier 28 is electrically conductively connected to the underside of the plate 21 with a flexible film 35 interposed therebetween. Furthermore, the underside of the plate 21 is electrically conductively connected to the flexible membrane 35 via partial metallizations 36 , 37 . Electrical connection plugs 38 are provided on the side of the circuit carrier 28 facing away from the plate 21 for electrical contacting of the transducer element 10 or the sound transducer assembly 10 .

The flexible membrane 35 connects two opposite sides of the plate 21 or of the fastening element 20 to one another. For this purpose the flexible membrane 35 is guided in the shape of a loop 39 or arc onto the upper side of the plate 21 and is connected to the metal via a conductive glue connection 41 in the region next to one of the transducer elements 10 . The layer 22 is electrically connected. A further collar 42 of the flexible membrane 35 is provided on the side of the plate 21 opposite the collar 39 and serves for electrical contacting of the piezoelectric element 15 , as can be seen in particular with reference to FIG. 2 . The flexible membrane 35 is connected, in particular via the further loop 42 , to the piezoelectric element 15 on the side opposite the respective base body 16 by means of an electrically conductive glue 43 . In the illustrated embodiment, the loop 39 of the flexible membrane 35 or the metallization layer 22 forms an electrical ground. The metallization layer 22 , which is at ground potential, is connected to the electrical ground of the circuit carrier 28 via a collar 39 . Furthermore, the three transducer elements 10 are electrically connected in parallel when they are operated as radiating elements. For the transducer element 10 acting as a receiving element, the piezo elements 15 are transferred individually to the circuit carrier 28 via the loop 42 of the flexible membrane 35 .

It is additionally mentioned that the electrical connection between the flexible film 35 and the board 21 or the circuit carrier 28 can also be realized differently. For example, it is possible for the flexible membrane 35 to be coupled to a plug-in connector which is located on the side of the circuit carrier 28 facing away from the board 21 . It is also conceivable that the circuit carrier 28 together with the flexible membrane 35 is designed as a so-called rigid-flex circuit board. The flexible film 35 can also terminate, for example, at partial metallizations 36 , 37 without forming an intermediate layer. Furthermore, it is conceivable for the flexible film 35 to be contacted laterally on the circuit carrier 28 or on the (lower) side of the circuit carrier 28 facing away from the plate 21 , for example via an electrically conductive glue connection or a soldered connection.

It can also be seen with reference to FIG. 2 that the acoustically active surface 12 or base body 16 of the transducer element 10 is closed flush with the outside of the bumper (not shown). Acoustic vibrations generated by the piezoelectric element 15 are transmitted via the acoustically active surface 12 , or acoustic vibrations received by the transducer element 10 from the environment are transmitted to the piezoelectric element 15 . Elastic bodies 46 can also be arranged between the individual piezoelectric elements 15 on the side of the plate 21 facing away from the flexible membrane 35 . The elastomer 46 serves for acoustic damping, decoupling and sealing of the transducer element 10 .

Furthermore, it can be provided that the intermediate space formed between the transducer elements 10 is filled with a damping mass 47 like the intermediate space formed between the fastening sides 17 , 18 . The damping substance 47 is especially an elastomer, such as Fermasil, or another damping material with or without gas inclusions. The damping mass 47 can also be an embedded damping pad. In order to introduce damping mass 47 into the intermediate space it can be provided that, as can be seen with reference to FIGS. The element 10 has a beveled edge 49 on one side. For dosing the damping substance 47 , for example, a dosing needle can be inserted through the through-opening 48 .

In the embodiments described so far, the front side of the plate 21 is electrically conductively connected to its rear side via the flexible film 35 . Alternative measures for the electrical connection between the front and back of the plate 21 or of the fastening element 20 will now be explained with reference to FIGS. 3 and 4 . It can be seen in FIG. 3 that next to the through opening 48 the plate 21 has a plurality of through openings 51 which connect the front side of the plate 21 to the rear side. Through-openings 51 (designed to correspond to through-openings 48 ) can form vias between the metallization layer 22 and the metallization formed on the other side of the plate 21 by making the through-openings 51 is metallized. Furthermore, the through-opening 51 can also be used for metering the damping substance 47 .

FIG. 4 shows the situation in which the side 52 of the plate 21 is provided with a metallization 53, which metallizes the metallization 54 formed on the front side (on which the transducer element 10 is arranged). part) and the metallization 55 formed on the rear side of the board 21 are electrically connected to each other.

The plate-shaped fastening element 20 with a rectangular basic contour described so far is constructed as a one-piece component. Corresponding to FIGS. 5 and 6 , it can also be provided that the fastening element 20 consists of two partial elements 61 , 62 . In this case, the first sub-element 61 has, for example, in a central region a recess 63 in the form of a cutout, in which the sub-element 62 , which for example has an approximately square base area, is arranged. A circumferentially running gap 65 is formed between the two subelements 61 , 62 . In the embodiment shown in FIG. 5 , gap 65 is completely filled with elastomer 66 . The elastic body 66 in particular has a relatively low modulus of elasticity in order to acoustically decouple the two subelements 61 , 62 relative to each other. In the embodiment shown in FIG. 6 , the two partial elements 61 , 62 are connected to each other only by means of elastomers 66 arranged in the corner regions of the recess.

The transducer element 10 can be operated either as a transmitting element or as a receiving element. Especially in the embodiment corresponding to FIGS. 4 and 5 , in which the fastening element 20 is composed of two partial elements 61 , 62 , it is advantageous if, for example, only the receiving element is arranged on the partial element 61 and only the receiving element is arranged on the other partial element 62 . Emitting elements are arranged. Corresponding to the illustration in FIG. 7 , three transducer elements 10 arranged parallel to one another are arranged on the second subelement 62 by way of example and function as radiation elements. The longitudinal axis 67 of the transducer element 10 or the acoustically active surface 12 runs parallel to the long sides of the rectangular plate 21 . In contrast, a plurality of transducer elements 10 designed as receiver elements are arranged on the first subelement 61 . In particular, it can be seen that two or one transducer element 10 is arranged on both sides of the narrow side of the transducer element 10 arranged on the second partial element 62 , the longitudinal axis 68 of said transducer element being arranged on the second partial element 62 . The longitudinal axis 67 of the transducer element 10 on the two-part element 62 is arranged at right angles.

The sound transducer assembly 100 described so far can be changed or modified in various forms and ways without departing from the inventive idea. In particular, the electrical contacting of the individual transducer elements 10 can be effected in other ways. This is the case, for example, when the carrier element 10 does not consist of metal but, for example, of plastic. It is also not necessary for the metallization layer 22 to be formed or arranged on both sides of the fastening element 20 . The electronic component or circuit carrier 28 can likewise be arranged separately from the fastening element 20 .

Claims (25)

1. A sound transducer assembly (100) having a plurality of transducer elements (10) connected to a common fixing element (20), wherein each transducer element (10) has at least one carrier element (11) A piezoelectric element (15) arranged in operative connection, and wherein the carrier element (11) is connected to the fixing element (20), characterized in that the fixing element (20) is determined by the modulus of elasticity Composition of material greater than 350x10 ³ N/mm ² and density greater than 2.5 g/cm ³ , wherein the fixing element (20) has at least two partial elements (61, 62), namely a second part element with a groove (63) A part element (61) and a second part element (62) arranged in said groove (63) forming a gap (65), wherein said gap (65) is at least partially filled with elastomer ( 66), and at least two transducer elements (10) are arranged on each of the two partial elements (61, 62). 2 . The sound transducer assembly according to claim 1 , characterized in that the fixing element ( 20 ) is configured in the shape of a plate ( 21 ) whose thickness (D) is between 3 mm and 20 mm. 3 . 3. The sound transducer assembly according to claim 1 or 2, characterized in that the material of the fastening element (20) comprises technical ceramics. 4. The sound transducer assembly according to claim 1 or 2, characterized in that the material of the fixing element (20) has metal. 5. The sound transducer assembly according to claim 3, characterized in that the fixing element (20) is provided with a metallization layer (22) at least on the side facing the transducer element (10) . 6. The sound transducer assembly according to claim 5, characterized in that the metallization layer (22) has a thickness between 8 μm and 20 μm and a surface resistance of 0.015Ω, and in the fixed element ( 20) and the metallization layer (22) form an adhesion strength between 170 N/mm ² and 230 N/mm ² . 7. The sound transducer assembly according to claim 5 or 6, characterized in that the fixing element (20) is provided with a metallization (36) on the side facing away from the transducer element (10) , 37; 55) or consist of metal, and the two sides of the fixing element (20) are arranged by means of another metallization (53) on the side (52) of the fixing element (20), or by means of They are electrically conductively connected to one another by means of connecting elements (35) or by means of through-openings (51) arranged in the fastening element (20) for forming through-contacts. 8. The sound transducer assembly as claimed in claim 1 or 2, characterized in that the carrier element (11) is connected to the fastening element (20) by means of an electrically conductive adhesive (23). 9. The sound transducer assembly according to claim 1 or 2, characterized in that the groove (63) has a closed contour. 10. The sound transducer assembly according to claim 1 or 2, characterized in that a plurality of parallel transducers acting as radiating elements are arranged on the first or second partial element (61, 62) element (10), and a transducer element (10) functioning as a receiving element is arranged on the second or first partial element (62, 61). 11. The sound transducer assembly according to claim 10, characterized in that the carrier element (11) of the transducer element (10) has a U-shaped transverse surface with a rectangular sound active surface (12). section, and the longitudinal axis (67) of the transducer element (10) acting as a transmitting element is relative to the longitudinal axis of at least some of the transducer elements (10) acting as a receiving element (68) Arranged rotationally. 12. The sound transducer assembly according to claim 1 or 2, characterized in that intermediate spaces present in the region of the carrier elements (11) and/or between carrier elements (11) are filled with Damping substance (47). 13. The sound transducer assembly according to claim 12, characterized in that the fastening element (20) has at least one further A through-opening (48) serves to supply the damping mass (47) into the intermediate space. 14. The sound transducer assembly according to claim 1 or 2, characterized in that the fixing element (20) and/or the carrier element (11) is surface-treated. 15. The sound transducer assembly as claimed in claim 1 or 2, characterized in that the sound transducer assembly is designed as a component of an auxiliary system or of a control system or of a regulating system. 16. The sound transducer assembly according to claim 1 or 2, characterized in that the fixing element (20) consists of a material with an elastic modulus of ^400x103N / ^mm2 . 17. The sound transducer assembly according to claim 2, characterized in that the thickness (D) of the plate (21 ) is between 3 mm and 6 mm. 18. The sound transducer assembly according to claim 3, characterized in that the material of the fixing element (20) has aluminum oxide. 19. The sound transducer assembly according to claim 4, characterized in that the material of the fixing element (20) has aluminum or steel. 20. The sound transducer assembly as claimed in claim 5, characterized in that the metallization layer (22) is embodied over the entire surface. 21. The sound transducer assembly according to claim 6, characterized in that an adhesion strength of 200 N/mm ² is formed between the fixing element (20) and the metallization layer (22). 22. The sound transducer assembly according to claim 7, characterized in that the connecting element (35) is configured in the form of a flexible membrane. 23. The sound transducer assembly according to claim 11, characterized in that the longitudinal axis (67) of the transducer element (10) acting as a transmitting element is relative to the transducer element acting as a receiving element The longitudinal axes (68) of at least some of the transducer elements in (10) are arranged rotated by 90 degrees. 24. The sound transducer assembly according to claim 14, characterized in that the fixing element (20) and/or the carrier element (11) are treated by plasma or by etching. 25. The sound transducer assembly of claim 15, wherein the assistance system is a driver assistance system in a vehicle.

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