EP3295683B1 - Sound converter arrangement with mems sound converters - Google Patents

Description

The present invention relates to a sound transducer arrangement having a first and a second MEMS sound transducer for generating and/or detecting sound waves in the audible wavelength spectrum, each comprising a cavity, and having an ASIC electrically connected to the first MEMS sound transducer. Such sound transducer arrangements can have very small dimensions and are therefore installed as loudspeakers and/or microphones, for example, in hearing aids, in-ear headphones, mobile phones, tablet computers and other electronic devices that only offer little installation space.

The term MEMS stands for microelectromechanical systems. A MEMS transducer for sound generation or a MEMS speaker is for example from DE 10 2012 220 819 A1 famous. The sound is generated via an oscillating membrane of the MEMS loudspeaker. Such sound transducer arrangements are constructed specifically according to the acoustic and other requirements of the respective area of application and consist of a large number of different elements. A major disadvantage of such sound transducer arrangements is that their manufacture is correspondingly complex, time-consuming and costly.

From the US 2012/0087521 A1 and DE 10 2011 086 722 A1 a sound transducer arrangement is known in each case, which has a substrate in which an ASIC is embedded.

From the EP 2 393 307 A2 a sound transducer arrangement is known which comprises a first substrate with a switching element and a second substrate with a microphone chip. The two substrates are connected to one another in an electrically conductive manner.

From the DE 10 2014 214 153 A1 discloses a surface mount microphone package that includes a first microphone and a second microphone. Furthermore, the surface-mount microphone package includes a first opening for the first microphone and a second opening for the second microphone. The first opening and the second opening are located on opposite sides of the surface mount microphone package.

It is the object of the present invention to provide a sound transducer arrangement that is simple to construct and to produce.

The object is solved by a sound transducer arrangement with the features of independent patent claim 1.

An acoustic transducer arrangement is proposed with a first MEMS acoustic transducer, which includes a first cavity, and with an ASIC that is electrically connected to the first MEMS acoustic transducer. The MEMS sound transducer is a microelectromechanical system for generating and/or detecting sound waves in the audible wavelength spectrum. The MEMS sound transducer is preferably driven electromechanically, electrostatically and/or piezoelectrically. The ASIC is an electronic application-specific integrated circuit suitable for operating the MEMS transducer. The term "cavity" is to be understood as meaning a cavity by means of which the sound pressure of the MEMS sound transducer can be amplified. The ASIC is embedded in a first substrate while the first MEMS transducer is disposed on a second substrate. The first substrate with the integrated ASIC and the second substrate with the at least partially integrated MEMS sound transducer thus represent two separate components, ie components manufactured separately from one another. The first and the second substrate are connected to one another. They thus have a common connection area in which they are in direct contact with one another. The connection between the two substrates is preferably by material connection produced, these are preferably glued together. In addition or as an alternative, however, the connection can also be made by means of a form fit and/or force fit. The two substrates are connected to one another in such a way that the ASIC and the first MEMS sound transducer are electrically conductively coupled or connected to one another.

A certain amount of rejects is inevitable in the production of sound transducer arrangements. With the sound transducer arrangement according to the invention, the additional costs arising from rejects can be reduced by initially producing the substrates separately from one another. Thereafter, the functionality of their respective at least one electronic component, i.e. the ASIC or the MEMS sound transducer, is checked. Only after a positive check of their functionality - i.e. when it is ensured that the ASIC and/or the MEMS sound transducer has not been damaged during the respective integration or embedding process - are they connected to each other, in particular glued. In this way it can be ensured that only two functional substrates are connected to one another to form a sound transducer arrangement.

The proposed sound transducer arrangement offers many advantages. If the ASIC is completely integrated into the first substrate and the first cavity is formed at least partially in the second substrate, the sound transducer arrangement can be formed in a very space-saving manner. It is advantageous if the first cavity is additionally formed in the first substrate.

Thanks to the modular structure with at least two separate substrates, of which the first substrate contains the ASIC and the second substrate carries the MEMS sound transducer, the sound transducer arrangement can be manufactured much more efficiently.

The individual modules, which either comprise a first substrate and an ASIC (hereinafter referred to as ASIC module for short) or a second substrate and a MEMS sound transducer (hereinafter referred to as MEMS module for short), can be produced, tested and tested independently of one another in respective sub-processes be temporarily stored if necessary. Each of these sub-processes can be specifically optimized. The design of the ASIC module and the MEMS module can also be specifically optimized.

Connecting an ASIC module and a MEMS module can take place late in the manufacturing process. This connection can take place in particular by soldering, conductive adhesive and/or in another suitable manner, so that the first and the second substrate are at least electrically and preferably also positively, non-positively and/or cohesively connected to one another.

Due to the possibility of producing the respective modules separately, the ASIC modules and/or the MEMS modules can also be manufactured in different variants and then combined to form different sound transducer arrangements, for example by combining different MEMS module variants with an ASIC module variant or a MEMS module variant can be combined with different ASIC module variants. This enables the flexible design of an extensive product family of different sound transducer arrangements while at the same time exploiting economies of scale.

Due to the possibility of separate testing, individual faulty modules can be identified and sorted out in a targeted manner at an early stage, so that on the one hand only two flawless modules are assembled to form a sound transducer arrangement and on the other hand only individual defective modules have to be disposed of. This reduces the amount of rejects, saves valuable resources, protects the environment and lowers costs. Preferably, the connection between the two modules or between the first and the second substrate are designed to be detachable, so that later in the event of repairs only the defective one of the two modules has to be replaced with a new module.

The first cavity is at least partially formed in the second substrate. As a result, a particularly large volume of the cavity can be achieved. It is advantageous if the first cavity is additionally formed in the first substrate.

A second MEMS sound transducer is arranged on a third substrate. In this case, the first substrate and the third substrate are electrically connected to one another. Accordingly, such an acoustic transducer arrangement comprises the first substrate with the ASIC, the second substrate with the first MEMS acoustic transducer and the third substrate with the second MEMS acoustic transducer. The first substrate is arranged between the second substrate and the third substrate. The second MEMS sound transducer also includes a cavity, this second cavity being formed at least partially in the third substrate and advantageously additionally in the first substrate.

The modular design of the sound transducer arrangement thus advantageously enables the ASIC module to be connected to a further MEMS module, which comprises a third substrate and a second MEMS sound transducer. This connection can also take place in particular by soldering, conductive adhesive and/or in another suitable manner, so that the first and the second substrate are at least electrically and preferably also positively, non-positively and/or cohesively connected to one another.

It goes without saying that the features and advantages already mentioned above with regard to the ASIC module and the MEMS module essentially also apply with regard to the further MEMS module.

In the case of a sound transducer arrangement with two MEMS modules, the two MEMS modules can essentially be designed with the same or different characteristic properties. In both cases, the acoustic transducer arrangement equipped with two MEMS modules usually has a better performance, in particular in the form of a greater bandwidth and/or greater sound pressure, than if it were equipped with only a single MEMS module.

The two cavities of the MEMS sound transducers are separated from one another by an intermediate wall of the first substrate, with the two cavities thus not influencing one another. The intermediate wall preferably has at least one connection opening extending from the first cavity to the second cavity, so that there is a flow connection between the two cavities and the volume of one cavity is increased by the volume of the other cavity. The sound transducer arrangement can thus be designed in a very space-saving manner with a nevertheless relatively large acoustically effective cavity volume.

It is advantageous if the partition wall has at least one stiffening element, in particular in the form of a rib, which stabilizes the partition wall and thus prevents, or at least significantly reduces, deformation and/or oscillation of the partition wall.

The two cavities preferably have volumes of different sizes. Thus, the cavity volume can be a characteristic in which the MEMS modules differ.

The substrates, namely the first, second and third substrate, are each designed as a circuit board or PCB (printed circuit board) and/or are produced using PCB technology.

The first, second and third substrates are each a PCB substrate, ie a printed circuit board that is made up of one or preferably multiple layers, the multiple layers being arranged on top of one another in the manner of a sandwich and/or being connected to one another, preferably with a material bond. In particular, the first substrate can have a recess for the integrative accommodation of the ASIC, which is designed, for example, as a printed circuit board cavity with a sufficiently large volume that the ASIC can be arranged or embedded therein. In addition to the ASIC, further components, in particular passive components such as electrical resistors and/or I/O contacts, can also be embedded in and/or arranged on the first substrate. The housing part and/or the sound-conducting element preferably consist of a material that is different from the substrate, in particular a plastic and/or metal.

It is advantageous if the substrates are manufactured separately from one another. In this case, the ASIC is embedded or encapsulated in the production of the first substrate. As a result, the ASIC and/or additional active and/or passive electronic components are fully integrated in the first substrate. Furthermore, it is advantageous if the second substrate is manufactured separately together with the MEMS sound transducer. In this case, the MEMS sound transducer can be fastened, for example, on one side of the second substrate, in particular in a materially bonded manner. Additionally or alternatively, however, the MEMS sound transducer can also be connected to the second substrate in a form-fitting manner. For this purpose, for example, a frame of the MEMS sound transducer is encompassed by the second substrate in a form-fitting manner. However, the membrane can vibrate freely. After each module - ie in particular the first module comprising the ASIC and the first substrate and/or the second module comprising the MEMS sound transducer and the second substrate - has been manufactured in a separate manufacturing step, they are connected to one another in a subsequent manufacturing step, in particular glued . Advantageously, therefore, the functionality the module can be checked before its final connection, so that the scrap and consequently the manufacturing costs can be reduced.

FIG. 1

ein nicht durch die beanspruchte Erfindung abgedecktes erstes Ausführungsbeispiel der Schallwandleranordnung ohne Gehäuseteil in einer perspektivischen Schnittansicht,

FIG. 2

das nicht durch die beanspruchte Erfindung abgedeckte erste Ausführungsbeispiel der Schallwandleranordnung ohne Gehäuseteil in einer seitlichen Schnittansicht,

FIG. 3

das nicht durch die beanspruchte Erfindung abgedeckte erste Ausführungsbeispiel der Schallwandleranordnung ohne Gehäuseteil in einer anderen seitlichen Schnittansicht,

FIG. 4

ein nicht durch die beanspruchte Erfindung abgedecktes zweites Ausführungsbeispiel der Schallwandleranordnung mit einem Gehäuseteil in einer perspektivischen Schnittansicht,

FIG. 5

das nicht durch die beanspruchte Erfindung abgedeckte zweite Ausführungsbeispiel der Schallwandleranordnung mit Gehäuseteil in einer seitlichen Schnittansicht,

FIG. 6

das nicht durch die beanspruchte Erfindung abgedeckte zweite Ausführungsbeispiel der Schallwandleranordnung ohne Gehäuseteil in einer anderen seitlichen Schnittansicht,

FIG. 7

ein nicht durch die beanspruchte Erfindung abgedecktes drittes Ausführungsbeispiel der Schallwandleranordnung mit Gehäuseteil in einer perspektivischen Schnittansicht,

FIG. 8

das nicht durch die beanspruchte Erfindung abgedeckte dritte Ausführungsbeispiel der Schallwandleranordnung in einer perspektivischen Explosionsansicht,

FIG. 9

das nicht durch die beanspruchte Erfindung abgedeckte dritte Ausführungsbeispiel der Schallwandleranordnung mit Gehäuse in einer perspektivischen Gesamtansicht,

FIG. 10

ein nicht durch die beanspruchte Erfindung abgedecktes viertes Ausführungsbeispiel der Schallwandleranordnung mit Gehäuse und mit porösem Material gefüllter Kavität in einer seitlichen Schnittansicht,

FIG. 11

ein nicht durch die beanspruchte Erfindung abgedecktes fünftes Ausführungsbeispiel der Schallwandleranordnung mit Gehäuse und mit porösem Material gefüllter Kavität in einer seitlichen Schnittansicht,

FIG. 12

ein nicht durch die beanspruchte Erfindung abgedecktes sechstes Ausführungsbeispiel der Schallwandleranordnung ohne Gehäuse in einer schematisch dargestellten seitlichen Schnittansicht,

FIG. 13

ein siebtes Ausführungsbeispiel der Schallwandleranordnung ohne Gehäuse jedoch mit zwei MEMS-Schallwandlern in einer schematisch dargestellten seitlichen Schnittansicht,

FIG. 14

ein achtes Ausführungsbeispiel der Schallwandleranordnung mit Gehäuse und zwei MEMS-Schallwandlern in einer seitlichen Schnittansicht,

FIG. 15

ein nicht durch die beanspruchte Erfindung abgedecktes neuntes Ausführungsbeispiel der Schallwandleranordnung ohne Gehäuseteil in einer perspektivischen Schnittansicht,

FIG. 16

das nicht durch die beanspruchte Erfindung abgedeckte neunte Ausführungsbeispiel der Schallwandleranordnung ohne Gehäuseteil in einer seitlichen Schnittansicht,

FIG. 17

das nicht durch die beanspruchte Erfindung abgedeckte neunte Ausführungsbeispiel der Schallwandleranordnung ohne Gehäuseteil in einer anderen seitlichen Schnittansicht,

FIG. 18

ein nicht durch die beanspruchte Erfindung abgedecktes zehntes Ausführungsbeispiel der Schallwandleranordnung mit einem Gehäuseteil in einer perspektivischen Schnittansicht,

FIG. 19

das nicht durch die beanspruchte Erfindung abgedeckte zehnte Ausführungsbeispiel der Schallwandleranordnung mit Gehäuseteil in einer seitlichen Schnittansicht,

FIG. 20

das nicht durch die beanspruchte Erfindung abgedeckte zehnte Ausführungsbeispiel der Schallwandleranordnung ohne Gehäuseteil in einer anderen seitlichen Schnittansicht,

FIG. 21

ein nicht durch die beanspruchte Erfindung abgedecktes elftes Ausführungsbeispiel der Schallwandleranordnung ohne Gehäuseteil in einer perspektivischen Schnittansicht,

FIG. 22

das nicht durch die beanspruchte Erfindung abgedeckte elfte Ausführungsbeispiel der Schallwandleranordnung ohne Gehäuseteil in einer seitlichen Schnittansicht,

FIG. 23

das nicht durch die beanspruchte Erfindung abgedeckte elfte Ausführungsbeispiel der Schallwandleranordnung ohne Gehäuseteil in einer anderen seitlichen Schnittansicht,

FIG. 24

ein nicht durch die beanspruchte Erfindung abgedecktes zwölftes Ausführungsbeispiel der Schallwandleranordnung mit einem Gehäuseteil in einer perspektivischen Schnittansicht,

FIG. 25

das nicht durch die beanspruchte Erfindung abgedeckte zwölfte Ausführungsbeispiel der Schallwandleranordnung mit Gehäuseteil in einer seitlichen Schnittansicht,

FIG. 26

das nicht durch die beanspruchte Erfindung abgedeckte zwölfte Ausführungsbeispiel der Schallwandleranordnung ohne Gehäuseteil in einer anderen seitlichen Schnittansicht.

Further advantages of the invention are described in the following exemplary embodiments. It shows:

FIG. 1

a not covered by the claimed invention first embodiment of the sound transducer assembly without housing part in a perspective sectional view,

FIG. 2

the first exemplary embodiment of the sound transducer arrangement, not covered by the claimed invention, without a housing part in a lateral sectional view,

FIG. 3

the first exemplary embodiment of the sound transducer arrangement, which is not covered by the claimed invention, without a housing part in another lateral sectional view,

FIG. 4

a second exemplary embodiment of the sound transducer arrangement, not covered by the claimed invention, with a housing part in a perspective sectional view,

FIG. 5

the second exemplary embodiment of the sound transducer arrangement with the housing part, which is not covered by the claimed invention, in a lateral sectional view,

FIG. 6

the second exemplary embodiment of the sound transducer arrangement, not covered by the claimed invention, without a housing part in a different lateral sectional view,

FIG. 7

a third exemplary embodiment of the sound transducer arrangement with a housing part, which is not covered by the claimed invention, in a perspective sectional view,

FIG. 8th

the third exemplary embodiment of the sound transducer arrangement, which is not covered by the claimed invention, in a perspective exploded view,

FIG. 9

the third exemplary embodiment of the sound transducer arrangement with housing, which is not covered by the claimed invention, in a perspective overall view,

FIG. 10

a fourth exemplary embodiment of the sound transducer arrangement, not covered by the claimed invention, with a housing and a cavity filled with porous material in a lateral sectional view,

FIG. 11

a fifth exemplary embodiment of the sound transducer arrangement, not covered by the claimed invention, with a housing and a cavity filled with porous material in a side sectional view,

FIG. 12

a sixth exemplary embodiment of the sound transducer arrangement without a housing, not covered by the claimed invention, in a schematically illustrated lateral sectional view,

FIG. 13

a seventh exemplary embodiment of the sound transducer arrangement without a housing but with two MEMS sound transducers in a schematically illustrated lateral sectional view,

FIG. 14

an eighth exemplary embodiment of the sound transducer arrangement with housing and two MEMS sound transducers in a side sectional view,

FIG. 15

a ninth exemplary embodiment of the sound transducer arrangement without a housing part, which is not covered by the claimed invention, in a perspective sectional view,

FIG. 16

the ninth exemplary embodiment of the sound transducer arrangement, not covered by the claimed invention, without a housing part in a lateral sectional view,

FIG. 17

the ninth exemplary embodiment of the sound transducer arrangement, which is not covered by the claimed invention, without a housing part in another lateral sectional view,

FIG. 18

a tenth exemplary embodiment of the sound transducer arrangement, not covered by the claimed invention, with a housing part in a perspective sectional view,

FIG. 19

the tenth exemplary embodiment of the sound transducer arrangement with housing part, which is not covered by the claimed invention, in a lateral sectional view,

FIG. 20

the tenth exemplary embodiment of the sound transducer arrangement without a housing part, which is not covered by the claimed invention, in another lateral sectional view,

FIG. 21

an eleventh exemplary embodiment of the sound transducer arrangement without a housing part, which is not covered by the claimed invention, in a perspective sectional view,

FIG. 22

the eleventh embodiment of the sound transducer arrangement not covered by the claimed invention without a housing part in a lateral sectional view,

FIG. 23

the eleventh exemplary embodiment of the sound transducer arrangement, which is not covered by the claimed invention, without a housing part in another lateral sectional view,

FIG. 24

a twelfth exemplary embodiment of the sound transducer arrangement, not covered by the claimed invention, with a housing part in a perspective sectional view,

FIG. 25

the twelfth exemplary embodiment of the sound transducer arrangement with housing part, which is not covered by the claimed invention, in a lateral sectional view,

FIG. 26

the twelfth exemplary embodiment of the sound transducer arrangement, which is not covered by the claimed invention, without a housing part in another lateral sectional view.

In the following description of the figures, in order to define the relationships between the various elements, relative terms such as above, below, above, below, above, below, left, right, vertical and horizontal, used. It goes without saying that these terms can change if the position of the devices and/or elements deviates from the position shown in the figures. Accordingly, for example, in the case of an inverted orientation of the devices and/or elements shown in relation to the figures, a feature specified as above in the following description of the figures would now be arranged below. The relative terms used thus only serve to simplify the description of the relative relationships between the individual devices and/or elements described below.

the Figures 1 to 3 show a first exemplary embodiment of a sound transducer arrangement 1, which is not covered by the claimed invention, in different views. The sound transducer arrangement 1 essentially comprises a first substrate 10 designed as a printed circuit board with an ASIC 11 and a second substrate 20 designed as a printed circuit board with a MEMS sound transducer 21. The MEMS sound transducer 21 is provided with electrical contacts that are not shown in detail in the figures connected to the ASIC 11. The MEMS sound transducer 21 can thus be controlled or operated via the ASIC 11 . The sound transducer arrangement 1 has an essentially rectangular basic shape. Having a rectangular basic shape, the sound transducer arrangement can be produced easily and inexpensively and is suitable for numerous application purposes. Alternatively, however, the sound transducer arrangement can in principle also have a different basic shape, in particular a round shape.

The MEMS sound transducer 21 is designed in such a way that it can generate and/or detect sound waves in the audible wavelength spectrum. For this purpose, the MEMS sound transducer 21 comprises, in addition to a MEMS actuator 22, as additional, in particular acoustic, components, a membrane 23, a membrane plate 24 and a membrane frame 25. The membrane 23, which is made of rubber, for example, is fixed in its edge area connected to the membrane frame 25, while it is firmly connected to the membrane plate 24, in particular in its middle region, the membrane plate 24 itself not being connected to the membrane frame 25. The membrane 23 thus spans the membrane frame 25 and is reinforced by the membrane plate 24 in particular in its central region. If the MEMS transducer 21 is to act as a speaker, for example, it can be excited via the ASIC 11 in such a way that the MEMS actuator 22, the membrane 23 for generating sound energy relative to the membrane frame 25 is vibrated.

The second substrate 20 carries the MEMS actuator 22 and the membrane frame 25 with the membrane 23 attached thereto, the MEMS actuator 22 being arranged below the membrane 23, and the second substrate 20 below the membrane 23 and the MEMS actuator 22 has a cavity 29 . The cavity 29 is laterally surrounded or delimited by walls 27 of the second substrate 20, while it is closed at the top by the membrane 23. The cavity 29 is closed at the bottom by the first substrate 10 to which the second substrate 20 is connected. The cavity 29 thus forms the cavity 41 of the MEMS sound transducer 21, which is used in particular to increase the sound pressure of the MEMS sound transducer 21.

How from the Figures 1 to 3 can be seen, the membrane frame 25 has essentially the same outer diameter as the second substrate 20, while the MEMS actuator 22 has a smaller outer diameter than the substrate 20. How from the figures 1 and 2 in comparison to figure 3 As can be seen, the essentially opposing wall sections 27a of the second substrate 20 are thicker than the wall sections 27b of the second substrate 20, the thicker wall sections 27a projecting into the cavity 29 compared to the wall sections 27b. The MEMS actuator 22 only rests on the projections 28 formed by the wall sections 27a, while the membrane frame 25 rests, in particular over the entire circumference, on both the wall sections 27a and 27b. Thus, the MEMS actuator 22 is surrounded by the membrane frame 25 on the side.

The MEMS sound transducer 21 and in particular the MEMS actuator 22 and/or the membrane frame 25 can be glued to the second substrate 20 be. Furthermore, the second substrate 20 can be glued to the first substrate 10 .

In order to be able to ensure pressure equalization between the cavity 41 and the environment when the membrane 23 vibrates, the sound transducer arrangement 1 has at least one pressure equalization channel 70, which in this exemplary embodiment comprises an equalization opening 26, which is preferably not on one of the thick wall sections 27, but on one of the thin wall portions 27 of the second substrate 20 is arranged. To equalize the pressure, air can flow out of the cavity 41 formed by the hollow space 29 through the pressure equalization channel 70 when the membrane 23 is lowered. In an analogous manner, however, air can also flow into the cavity 41 via the pressure compensation channel 70 when the membrane 23 is lifted.

The first substrate 10 has a cavity 13a which is essentially completely closed. The ASIC 11 is arranged in the cavity 13a. The ASIC 11 is thus completely embedded in the first substrate 10 . In addition to the ASIC 11, the sound transducer arrangement 1 has electrical, in particular passive, additional components 12a, 12b, such as electrical resistors and/or I/O contacts. These additional components 12a, 12b are also embedded in the first substrate 10, being arranged in the further cavity 13b of the substrate 10, which is also essentially completely closed. Alternatively, the additional electronic components 12a, 12b could also be arranged together with the ASIC 11 in the cavity 13a.

In the Figures 4 to 26 further embodiments of the sound transducer arrangement 1 are shown, with the differences in relation to the first embodiment already described being essentially discussed in each case. In the following description of the further embodiments, the same reference symbols are used for the same features. Provided these are not explained in detail again, their design and mode of operation corresponds to the features already described above. The differences described below can be combined with the features of the respective preceding and following exemplary embodiments.

the Figures 4 to 6 show a second embodiment of the sound transducer arrangement 1, which is not covered by the claimed invention, in different views. In contrast to the first exemplary embodiment, a housing part 50 is additionally provided in the second exemplary embodiment of the sound transducer arrangement 1 . In particular, this housing part 50 offers protection for the MEMS sound transducer 21. The housing part 50 has a cavity 53 in which the second substrate 20 and the MEMS sound transducer 21 are essentially completely received, and which extends downwards from the first substrate 10 is closed, with which the housing part 50 is connected.

The housing part 50 also has an acoustic inlet/outlet opening 51 which is arranged laterally on the outer surface 55 of the housing part and thus also on the sound transducer arrangement. In addition, the housing part 50 is connected to the first substrate 10 and in particular also dimensioned such that at least a first section 62 of a sound-conducting channel 61 is formed between the housing part 50 and the second substrate 20 with the MEMS sound transducer 21 . A second section 63 of the sound-conducting channel 61 is formed in the housing part 50 itself. For this purpose, the housing part 50 has a tubular projection 52 in the area of the acoustic inlet/outlet opening 51 . As a result, no additional components are required to form the sound-conducting channel 61 . In other words, the sound conduction channel 61 is at least partially formed in that the cavity 53 of the housing part 50 is not completely filled by the second substrate 20 and the MEMS sound transducer 21 .

Sound can be directed and/or amplified by means of the sound conduction channel 61 from the MEMS sound transducer 21 to the acoustic entry/exit opening 51 and/or vice versa. Thanks to the sound conduction channel 61, the acoustic inlet/outlet opening 51 can be positioned essentially anywhere on the outer surface 55 or another outer surface of the sound transducer arrangement 1, in particular on an installation-oriented upper side and/or on a side surface.

The housing part 50 also has an acoustic equalization opening 56 which is arranged laterally on the outer surface 58 of the housing part 50 . The equalization opening 56 corresponds to the equalization opening 26 and, like this, belongs to the pressure equalization channel 70 of the sound transducer arrangement 1. In this example, the equalization opening 56 has a larger diameter than the equalization opening 26. This means that no dirt and/or liquid can enter the cavity through the pressure equalization channel 70 41, the compensation opening 56 is covered with an elastic closure element 57 in this example. The pressure equalization functionality is nevertheless ensured since the elastic closure element 57 can deform according to the pressure prevailing in the cavity 41 .

the Figures 7 to 9 show a third exemplary embodiment of the sound transducer arrangement 1, which is not covered by the claimed invention, in different views. As an essential difference compared to the first and second exemplary embodiment, in the third exemplary embodiment, the cavity 41 is in each case partially formed by a hollow space in the first and second substrate 10, 20.

As in particular from the figures 7 and 8th can be seen, the membrane frame 25 has essentially the same outer diameter as the MEMS actuator 22, with this outer diameter being smaller than the outer diameter of the second substrate 20. However, the walls 27 of the second substrate 20, which contain the cavity 29 of the second substrate laterally delimiting wall sections 27b projecting into the cavity 29 at their upper area, which provide a preferably full-circumferential support 28 for the MEMS actuator 22, the membrane frame 25 also resting on the outer edge area of the MEMS actuator 22. Thus, in this example, too, the second substrate 20 carries the MEMS actuator 22 and the membrane frame 25 with the membrane 23 attached thereto, with the MEMS actuator 22 being arranged below the membrane 23 and with the second substrate 20 below the membrane 23 and the MEMS actuator 22 has the cavity 29 which is closed at the top by the membrane 23.

The cavity 29 of the second substrate 20 is open at the bottom and borders on the cavity 15 of the first substrate 10, which is open at the top. The cavities 15 and 29 have the same diameter and the lower free ends of the walls 27 correspond to the upper free ends of the walls 16. In the installed state of the sound transducer arrangement 1, the walls 16 of the first substrate 10 are connected to the walls 27 of the second substrate 20 connected and in particular glued, the cavity 15 of the first substrate and the cavity 29 of the second substrate being arranged one above the other and then together forming the cavity 41 for the MEMS sound transducer 21 .

A pressure compensation channel 70 is not shown in the figures for this example, but can preferably be provided.

The housing part 50 is very economical in this example and, in addition to the outer surface 55 on which the acoustic inlet/outlet opening 51 with the tubular projection 52 is arranged, essentially only has one further outer surface 54, which in particular provides protection for the MEMS transducer 21 provides.

The housing part 50 is nevertheless connected to the first substrate 10 and the second substrate 20 in such a way that at least a first section 62 of a sound duct 61 is formed between the housing part 50 and the second substrate 20 with the MEMS sound transducer 21 and the first substrate 10. In this example, too, the second section 63 of the sound-conducting channel 61 is formed in the housing part 50 itself and in particular by the tubular projection 52 .

To further improve the sound conduction and in particular to focus the sound, the sound-conducting element 64 is provided with a concave sound-conducting edge 65 in this example, which is arranged between the housing part 50 and the first and second substrate within the sound-conducting channel 61 . More precisely, the sound-conducting element 64 is arranged in the transition area between the first and second sections 62, 63 of the sound-conducting channel 61. The sound-conducting element is designed here as a single component. Alternatively, however, it can also be formed on the housing part 50 and/or on a substrate.

The sound-conducting element 64 is particularly in the Figures 8 and 9 clearly visible. the figure 8 shows the sound transducer arrangement 1 of the third exemplary embodiment in an exploded view. As a result, in addition to the sound-conducting element 64 with the concave sound-conducting edge 65, the other components of the sound transducer arrangement 1, such as the ASIC 11, the substrates 10 and 20 and, above all, the MEMS actuator 22, the membrane 23 on the membrane frame 25 and the membrane plate 24 very recognizable. In the figure 9 the housing part 50 is shown semi-transparent, so that the protected components of the sound transducer arrangement 1 located behind it can still be clearly seen.

the figure 10 shows a fourth exemplary embodiment of the sound transducer arrangement 1, which is not covered by the claimed invention. In contrast to the third exemplary embodiment, in the fourth exemplary embodiment of the sound transducer arrangement 1, the cavity 41 is at least approximately completely filled with a porous material 5.

the figure 11 shows a fifth exemplary embodiment of the sound transducer arrangement 1 not covered by the claimed invention. In contrast to the second exemplary embodiment, in the fifth exemplary embodiment of the sound transducer arrangement 1 the cavity 41 is at least almost completely filled with a porous material 5.

The filling of the cavity 41 of the MEMS sound transducer 21 causes an effective increase in the surface area within the cavity and a virtual increase in the volume of the cavity, as a result of which greater sound pressure and better bass reproduction can be achieved.

the figure 12 shows a sixth exemplary embodiment of the sound transducer arrangement 1 that is not covered by the claimed invention. This is a purely schematic representation of the sound transducer arrangement 1, which comprises a first substrate 10 with an ASIC 11 and a second substrate 20 with a MEMS sound transducer 21, however has no housing. Only the MEMS actuator 22 of the MEMS sound transducer 21 is shown here.

Both the first substrate 10 and the second substrate 20 have conductor tracks 7 for electrically connecting the individual components, such as ASIC 11 and MEMS actuator 21 in particular. The conductor tracks 7 of the first substrate 10 are connected to the conductor tracks 7 of the second substrate 20 by means of soldered connections 8 or electrically conductive adhesive 8 . In addition to these electrically conductive connections 8, the two substrates 10, 20 can also be connected to one another in other ways in a form-fitting, force-fitting and/or cohesive manner.

The second substrate 20 has a cavity 29 which is surrounded or delimited at the side by walls 27 of the second substrate 20 and is closed off at the bottom by the first substrate 10 . The walls 27 have wall sections 27a projecting into the cavity 29, which provide a support 28 for the MEMS actuator 22, which has a smaller outer diameter than the second substrate 20. The cavity 29 is closed at the top by the additional acoustic components of the MEMS sound transducer that belong to the MEMS actuator 22 but are not shown here. The cavity 29 thus forms the cavity 41 of the MEMS sound transducer.

the figure 13 shows a seventh embodiment of the sound transducer arrangement 1. This is again a purely schematic representation of the sound transducer arrangement 1. In contrast to the sixth embodiment, the sound transducer arrangement 1 of this seventh exemplary embodiment also includes a third substrate 30 with a second MEMS sound transducer, of which here only the MEMS actuator 32 is shown.

In this case, the first substrate 10 is arranged between the second substrate 20 and the third substrate 30 . The third substrate 30 with the second MEMS actuator 32 is constructed essentially like the second substrate 20 with the first MEMS actuator 22, but the third substrate 30 is arranged rotated by 180° compared to the second substrate 20.

The third substrate 30 therefore also has conductor tracks 7 for the electrical connection of the individual components. The conductor tracks 7 of the third substrate 30 are also connected to the conductor tracks 7 of the first substrate by means of soldered connections 8 or electrically conductive adhesive 8 . In addition to these electrically conductive connections 8, the two substrates 10, 30 can also be connected to one another in another way in a form-fitting, force-fitting and/or cohesive manner.

The third substrate 30 has a cavity 39 which is laterally surrounded or delimited by the walls 37 of the third substrate 30 and is closed at the top by the first substrate 10 . The hollow space 39 is closed at the bottom by the further acoustic components of the second MEMS sound transducer 31 which belong to the second MEMS actuator 32 but are not shown here. The cavity 39 thus forms the second cavity 42 of the second MEMS sound transducer.

In this seventh exemplary embodiment of the sound transducer arrangement 1, the first and the second cavity 41, 42 are formed separately, but essentially with the same characteristic properties such as, for example, dimensions and volume. The two cavities 41, 42 are separated from one another by an intermediate wall 17, which is provided by the first substrate 10, so that the two cavities 41, 42 do not affect one another. Optionally, however, the intermediate wall can also have at least one connection opening extending from the first cavity 41 to the second cavity 42, which is not shown here, however. This connection opening then enables a flow connection between the two cavities, so that the volume of one cavity is increased by the volume of the other cavity in each case.

the figure 14 shows an eighth exemplary embodiment of the sound transducer arrangement 1. In contrast to the third exemplary embodiment, the sound transducer arrangement 1 of this eighth exemplary embodiment additionally includes a third substrate 30 with a second MEMS sound transducer 31.

In this case, the first substrate 10 is arranged between the second substrate 20 and the third substrate 30 . The third substrate 30 with the second MEMS sound transducer 31 is constructed essentially like the second substrate 20 with the first MEMS sound transducer 21, but the third substrate 30 is arranged turned by 180° compared to the second substrate 20. Analogous to the cavity 15 on its upper side, the first substrate 10 has a cavity 18 on its underside, which is delimited laterally by walls 19 of the first substrate and is closed at the top by the first substrate 10 . The cavity 18 is open at the bottom and borders on the cavity 39 of the third substrate 30, which is open at the top. The cavity 39 is laterally surrounded or delimited by the walls 37 of the third substrate 30 and at the bottom by the membrane 33 of the second MEMS sound transducer 31 closed. The cavities 18 and 39 have the same diameter and the lower free ends of the walls 19 correspond to the upper free ends of the walls 37. In the mounted state of the sound transducer arrangement 1, the walls 19 of the first substrate 10 are connected to the walls 37 of the third substrate 30 connected and in particular glued, the cavity 18 of the first substrate and the cavity 39 of the third substrate being arranged one above the other and then together forming the cavity 42 for the MEMS sound transducer 31 .

In contrast to the seventh exemplary embodiment, the first and second cavities 41, 42 in this eighth exemplary embodiment have different characteristic properties and, in particular, different dimensions and different cavity volumes. This is essentially solely due to the fact that the walls 16 on the upper side of the first substrate 10 are higher than the walls 19 on the underside of the first substrate 10.

The first and second MEMS sound transducers 21, 31 will already reveal a different sound behavior due to the differently designed cavities 41, 42, even under otherwise identical conditions. Alternatively or additionally, the sound behavior of the two MEMS sound transducers can also be influenced in a targeted manner, for example, by specifically designing the membranes 23, 33 and/or the MEMS actuators 22, 32. Thus, for example, one of the MEMS transducers can act as a woofer and the other MEMS transducer can act as a tweeter, so that a sound transducer arrangement equipped in this way can generate sound in a larger bandwidth than, for example, a sound transducer arrangement according to the third exemplary embodiment.

The intermediate wall 17 provided by the first substrate 10, which separates the two cavities 41, 42 from one another, has four stiffening elements 14, which are designed as ribs and serve to stabilize the intermediate wall 17. Deformation and/or vibration of the intermediate wall 17, in particular during operation of the sound transducer arrangement 1, can be significantly reduced or even prevented as a result. According to the present exemplary embodiment, the intermediate wall 17 has at least one connection opening 90 . The connection opening 90 connects the two cavities 41, 42 to one another.

In this example, the housing part 50 is designed very sparingly, as in the third exemplary embodiment, and in addition to the outer surface 55, on which the acoustic inlet/outlet opening 51 with the tubular projection 52 is arranged, essentially only has the other outer surfaces 54a and 54b, which offer protection for the first MEMS sound transducer 21 and the second MEMS sound transducer 31 in particular.

However, the housing part 50 is also connected to the first substrate 10, the second substrate 20 and the third substrate 30 in such a way that a first and a second sound-conducting channel 61, 67 are formed. At least a first section 62 of the first sound-conducting channel 61 is located between the housing part 50 and in particular the second substrate 20 with the MEMS sound transducer 21, and at least a first section 68 of the second sound-conducting channel 67 is formed.

In order to save installation space in particular, only one acoustic inlet/outlet opening 51 is also provided in this sound transducer arrangement 1 . The second section 63 of the first sound-conducting channel 61 and the second section 69 of the second sound-conducting channel 67 are therefore formed as a common section, which in this example is also formed in the housing part 50 itself and in particular by the tubular projection 52 in the area of the acoustic inlet/outlet opening 51 is.

The sound-conducting element 64 is also provided in this example to further improve the sound conduction and in particular to focus the sound. The sound-conducting element 64 is designed and arranged in such a way that it separates the first section 62 of the first sound-conducting channel 61 from the first section 68 of the second sound-conducting channel 67 . For this purpose, the sound-conducting element 64 has an extension 66 projecting into the common second section. In addition, the sound-conducting element 64 has two concave sound-conducting edges 65a and 65b in this example, with the sound-conducting edge 65a being assigned to the first sound-conducting channel 61 and the sound-conducting edge 65b being assigned to the second sound-conducting channel 67 .

the Figures 15 to 17 show a ninth exemplary embodiment of the sound transducer arrangement 1, which is not covered by the claimed invention, in different views. In contrast to the first exemplary embodiment, an additional substrate 80 is provided in the ninth exemplary embodiment of the sound transducer arrangement 1 .

In the exemplary embodiment shown here too, membrane frame 25 has essentially the same outside diameter as second substrate 20 , while MEMS actuator 22 has a smaller outside diameter than substrate 20 . However, the walls 27 of the second substrate 20, which laterally delimit the cavity 29 of the second substrate 20, have no wall sections projecting into the cavity 29 that could serve as a support for the MEMS actuator 22. On the walls 27 of the second substrate 20 is therefore, in particular over the entire circumference, the additional substrate 80, which has essentially the same outer diameter as the second substrate 20.

The additional substrate 80 has a cavity 89 which is delimited laterally by walls 87 of the substrate 80, the walls 87 having a significantly lower height than the walls 27 of the second substrate 20. The substantially opposing wall sections 87a of the substrate 80 are thicker than the wall sections 87b of the substrate 80, the thicker wall sections 87a projecting into the cavity 89 in relation to the wall sections 87b. The MEMS actuator 22 then rests on the projections 88 formed by the wall sections 87a, while the membrane frame 25 rests, in particular over the entire circumference, both on the wall sections 87a and 87b. Thus, the MEMS actuator 22 is arranged below the membrane 23 and surrounded by the membrane frame 25 on the side.

The cavity 89 is thus closed by the membrane 23 at the top. The cavity 89 is open at the bottom and borders on the cavity 29 of the second substrate 20, which is open at the top and is closed by the first substrate 10 at the bottom. The cavities 29 and 89 arranged one above the other then together form the cavity 41 for the MEMS sound transducer 21. Since the walls 27 of the second substrate 20 do not have any wall sections projecting into the cavity 29, which would reduce the cavity 29, this contributes to increasing the through the cavity 29 with the cavity 41 formed.

the Figures 18 to 20 show a tenth exemplary embodiment of the sound transducer arrangement 1, which is not covered by the claimed invention, in different views. In contrast to the ninth exemplary embodiment, a housing part 50 is additionally provided in the tenth exemplary embodiment of the sound transducer arrangement 1, which is essentially as in FIG the second embodiment is formed. In contrast to the second exemplary embodiment, the additional substrate 80 is also accommodated in the cavity 53 of the housing part 50 in the tenth exemplary embodiment of the sound transducer arrangement 1 .

the Figures 21 to 23 show an eleventh exemplary embodiment of the sound transducer arrangement 1, which is not covered by the claimed invention, in different views. In contrast to the first exemplary embodiment, in the eleventh exemplary embodiment of the sound transducer arrangement 1, the second substrate 20, the MEMS actuator 22 and the membrane frame 25 of the first MEMS sound transducer 21 each have the same outside diameter.

The walls 27 of the second substrate 20, which laterally delimit the cavity 29 of the second substrate 20, have no wall sections projecting into the cavity 29 that would have to serve as a support for the MEMS actuator 22. Rather, the MEMS actuator 22 preferably rests on the walls 27 of the second substrate 20 over its entire circumference, with the membrane frame 25 also resting on the outer edge region of the MEMS actuator 22 .

Thus, in this example, too, the second substrate 20 carries the MEMS actuator 22 and the membrane frame 25 with the membrane 23 attached thereto, with the MEMS actuator 22 being arranged below the membrane 23, and with the second substrate 20 below the membrane 23 and of the MEMS actuator 22 has the cavity 29 which is closed at the top by the membrane 23.

The cavity 29 of the second substrate 20 is closed by the first substrate 10 at the bottom.

In this exemplary embodiment, too, the cavity 41 of the MEMS sound transducer 21 formed by the hollow space 29 could be enlarged effectively and at the same time in a very space-saving manner.

the Figures 24 to 26 show a twelfth exemplary embodiment of the sound transducer arrangement 1, which is not covered by the claimed invention, in different views. In contrast to the eleventh exemplary embodiment, a housing part 50 is additionally provided in the twelfth exemplary embodiment of the sound transducer arrangement 1, which is designed essentially as in the second exemplary embodiment.

Claims (5)

1. Sound transducer assembly (1)

   with a first substrate (10),

   a first and second MEMS sound transducer (21, 31) for generating and/or detecting sound waves in the audible wavelength spectrum, which each comprises a cavity (41, 42), and

   an ASIC (11) electrically connected to the first MEMS sound transducer (21),

   wherein the two cavities (41, 42) of the MEMS sound transducers (21, 31) are separated from one another by an intermediate wall (17) of the first substrate (10),

   characterized in that

   the ASIC (11) is embedded in the first substrate (10);

   the first MEMS sound transducer (21) is arranged on a second substrate (20) such that the cavity (41) of the first MEMS sound transducer (21) is at least partially formed in the second substrate (20), wherein a hollow space (29) of the second substrate (20) forming said cavity (41) is laterally surrounded or delimited by walls (27) of the second substrate (20) while being closed upwardly by a membrane (23) of the first MEMS sound transducer (21); ,

   the first substrate (10) and the second substrate (20) are connected to one another in such a manner that the ASIC (11) of the first substrate (10) and the first MEMS sound transducer (21) of the second substrate (20) are electrically coupled to one another;

   the second MEMS sound transducer (31) is arranged on a third substrate (30), that the cavity (42) of the second MEMS sound transducer (31) is formed at least partially in the third substrate (30), wherein a hollow space (39) of the third substrate (30) forming said cavity (42) is laterally surrounded or delimited by walls (37) of the third substrate (30) and being closed downwardly by a membrane (33) of the second MEMS sound transducer (31); the first substrate (10) and the third substrate (30) are connected to one another in an electrically conductive manner;

   the first substrate (10) is arranged between the second substrate (20) and the third substrate (30), and

   the substrates (10, 20, 30) are each in the form of a circuit board or PCB (printed circuit board).
2. The transducer assembly according to the preceding claim 1, characterized in that the cavity (41, 42) of the first and/or second MEMS sound transducer (21, 31) is additionally formed in the first substrate (10).
3. Sound transducer assembly according to one or more of the previous claims, characterized in that
   the intermediate wall (17) features at least one connection opening (90) and/or a connection channel extending from the first cavity (41) of the first MEMS sound transducer (21) to the second cavity (42) of the second MEMS sound transducer (31).
4. Sound transducer assembly according to one or more of the previous claims, characterized in that
   the intermediate wall (17) features at least one stiffening element (14), in particular a rib.
5. Sound transducer assembly according to one or more of the previous two claims, characterized in that
   the two cavities (41, 42) of the sound transducer assembly (1) feature volumes of different sizes.

Images