WO2023079126A1

WO2023079126A1 - Sound transducer device

Info

Publication number: WO2023079126A1
Application number: PCT/EP2022/080890
Authority: WO
Inventors: Rinaldo Persichini; Alexander RUDOY; Christian Welk
Original assignee: Toposens Gmbh
Priority date: 2021-11-08
Filing date: 2022-11-06
Publication date: 2023-05-11
Also published as: LU500838B1

Abstract

The invention relates to a sound transducer device (1) comprising a substrate (17) and a sound transducer (2) acoustically connected to one end of a sound channel (12) of the substrate (17). The sound transducer device is characterised in that the sound transducer device (1) comprises a waterproof acoustic membrane (5) covering another end of the sound channel (12).

Description

sound transducer device

The invention relates to a sound transducer device. Furthermore, the invention relates to a method for producing such a sound converter device, a sound converter device produced by means of the method, a communication device comprising the sound converter device and the use of the same.

Sound transducer devices must, in particular in communication applications and/or sensor applications, function properly and reliably for many years and must withstand a wide variety of environmental influences, in particular within the context of their respective application. In addition to a defined temperature range in the application, resistance to corrosive effects such as water, acids or oils and protection against the ingress of dust or other foreign bodies are relevant environmental influences to which sound transducer devices can be exposed. There are a number of standards to indicate resistance to such environmental influences. In particular, the protection classes IP69 and IP69K according to DIN EN 60529 (VDE 0470) (Version 2019) are used to identify electronic devices that meet the highest standards against dirt and moisture. The degree of protection consists of the letters "IP" ("International Protection" or "Ingress Protection") and two numbers. The first number stands for protection against dust and foreign bodies. The higher this number, the more powerful the device also protected against the finest dust. "6" stands for absolute dust tightness. The second number indicates the protection against water in different intensities or scenarios. While the 1 means protection against light dripping water, the 9 as the highest number implies protection against the ingress of water during high-pressure or steam jet cleaning.

Although both types of protection relate to the protection provided by enclosures, they differ in the scope of the devices concerned. The IP69k takes into account the special requirements for electrical or electronic devices in mobile outdoor applications such as road vehicles or agricultural machines. It is regulated in the ISO 20653:2013 standard. IP69 stands for the dust and water resistance of general electrical equipment, which also includes, for example, computers for use in various applications, e.g integrated capacitive touchscreen, or medical technology. The criteria are defined in the DIN EN60529 standard. The degrees of protection IP69 and IP69k do not stand for different qualities, but differ in their area of application ("Electrical equipment in general" and "Electrical equipment in road vehicles").

Acoustic transducer devices are used in many of these applications. In particular in applications that come into contact with environmental influences, in particular with water, dust or viscous liquids such as wax or tree resin, the sound transducer device must be protected from the environmental influences. It is known, for example, to use grilles to cover acoustic transducer devices. However, these have the disadvantage that they are not water-repellent and therefore do not meet protection classes IP69 or IP69K.

There is therefore a need to provide a sound transducer device that meets the requirements of protection classes IP69 and IP69K and at the same time sound reception, processing or transmission are not negatively affected and/or are still reliably possible. In addition, the ingress of liquids, even under pressure, must be avoided, for example by penetrating into slits, openings, or deep indentations. Furthermore, depending on the application, it may be necessary for the surface of the sound transducer device to be paintable.

The present invention is therefore based on the object of providing a sound transducer device which meets the requirements of IP69 and IP69K and thus provides reliable protection against the ingress of dust and liquids, such as water, tree resin or waxes in the liquid state Fulfills requirements for reliable sound signal processing, for example with regard to sufficient sensitivity in a predetermined frequency range.

This problem is solved by means of a sound transducer device specified in claim 1 . The sound transducer device according to the invention comprises a substrate and a sound transducer which is acoustically connected to one end of a sound channel of the substrate and is characterized in that the sound transducer device has a waterproof acoustic membrane covering another end of the sound channel.

A membrane within the meaning of the invention has an extent which, in a Cartesian coordinate system with the x, y and z axis in the z direction—corresponding to the membrane thickness in the installed position—has a smaller extent than in the x, y plane. An acoustic membrane is understood to mean a membrane which, after being attached to the substrate, can be set at least partially in vibration by sound pressure waves from the environment. The membrane vibration again causes sound pressure waves in the sound channel, which are received by the sound transducer. This is possible with membranes that are designed to be flexible, as will be explained in more detail below. As a result, the membrane prevents the sound pressure waves from the environment from being received directly by the sound transducer.

A membrane is considered watertight for the purposes of the invention if it passes the IP69 and/or IP69K degree of protection test. On the one hand, this allows reliable protection against the ingress of dust and liquids such as water, tree resin or waxes in the liquid aggregate state to be expected as environmental influences, on the other hand, the requirements for reliable sound signal processing, for example with regard to sufficient sensitivity in a predetermined frequency range, can be met.

In addition to this, the sound converter device according to the invention particularly advantageously allows the structurally simple adaptation of the sound converter device to a given installation space, since the membrane according to the invention transmits sound energy without itself requiring a large amount of additional installation space.

A sound transducer device is a device in which acoustic signals in the form of pressure waves are converted into electrical signals, in particular an electrical voltage, or vice versa, in which an electrical voltage is converted into acoustic signals in the form of pressure waves. The pressure waves are not limited to the frequency range that is audible to humans and therefore also include pressure waves outside the audible range. The sound transducer device can be designed as a microelectromechanical system (MEMS). An acoustic connection is understood to be a connection between two areas in which acoustic energy, in particular sound energy, can be transmitted from one area to another area. The transmission can take place through the same and/or different media. In addition, energy transfer may involve the conversion of mechanical energy, such as vibrational energy of the membrane, to acoustic energy, or vice versa.

In a further configuration of the sound transducer device, the substrate can have a control device or can be the control device or can be incorporated into the substrate. Alternatively or additionally, the substrate can have a control and/or signal conditioning device. The membrane can preferably be firmly connected to the substrate, in particular the control device. The control device can preferably include or be a printed circuit board (PCB). The printed circuit board serves as a carrier for electronic components, in particular for at least one data processing unit, such as one or more processors. Alternatively, it is also referred to as a printed circuit board. Alternatively or additionally, the printed circuit board can serve as a carrier for a control and/or signal conditioning device.

In the installation direction, the sound transducer can be arranged below the control device, in particular below the PCB. In particular, the sound transducer and the membrane can be arranged on opposite sides of the substrate. This has the advantage that the sound transducer according to the invention can be provided in a simple manner in terms of production technology, since the sound opening is arranged on the outside or the surrounding side in the installation direction of the sound transducer device. This protects the sound transducer device, including its substrate, in particular the control device, from dust or environmental influences such as water in particular, in a structurally simple manner, without requiring further measures on an application device for an application of the sound transducer which requires protection class IP69 and/or IP69K.

The outside of the sound converter device is understood to mean the side that faces the environment during operation of the sound converter device. The installation direction is understood to be the direction along which the sound transducer device is moved in order to install it in an application device. According to a further embodiment, the membrane can be arranged on the substrate, in particular glued on, in particular this can be done by means of at least one adhesive layer. This has the additional advantage that by arranging it directly on the substrate, preferably the control device, in particular a PCB, both the sound transducer and the substrate are structurally protected in a particularly simple and reliable manner against the ingress of environmental influences. With this type of attachment, the membrane can have a sound-transmitting area in the area of the sound channel. A sound-transmitting area is understood to be an area of the membrane which, when subjected to sound pressure waves, is completely or partially made to oscillate and thus transmits sound energy into the sound channel.

The other end of the sound channel may include a sound port. A sound opening is understood to be an opening through which sound pressure waves reach the sound channel. As described in more detail below, these sound pressure waves are generated through the membrane, particularly the sound-transmitting region of the membrane. The acoustic transducer device may be configured such that an acoustic pressure wave passes through the acoustic duct before being received by the acoustic transducer.

The sound converter can have a sound converter housing and a sound receiver and/or transmitter. The sound converter housing can at least partially enclose an interior space of the sound space. In addition, in the assembled state, the substrate can partially close off the interior of the sound transducer. The sound receiver and/or transmitter can be arranged in the interior of the sound transducer. In addition, the interior of the sound transducer can be acoustically connected to the sound opening.

The membrane can close off an acoustic space composed of the sound channel and the interior of the sound transducer. The acoustic space can be completely closed off by the aforementioned components. Such a configuration has the advantage that a predetermined resonance frequency range can be set in a structurally simple manner by providing a predetermined volume for the acoustic space. As a result, unwanted frequency ranges can be filtered out by the sound transducer device. Another advantage is that, In particular, the sound signal transmitted by the membrane, in particular the sound-transmitting area, is amplified.

Suitable membranes can have, for example, a polyimide, in particular a duroplastic polyimide, in particular poly(4,4′-oxydiphenylenepyromellitimide), also called Kapton, or be formed from it. This has the advantage that membranes of this type, and in particular Kapton, have very good resistance to chemicals, are waterproof in the sense of IP69 or IP69K and are also electrically insulating. Such membranes also have a high tensile strength (3 GPa), with such a membrane retaining its flexibility. Maintaining flexibility serves to prevent or at least minimize damping of the mechanical sound transmission energy. Tensile strength serves to prevent or at least minimize loss of resonance. Such membranes and in particular Kapton also have good temperature resistance, in particular in a range from -269°C to 400°C, as a result of which they have constant mechanical properties over the required temperature range of -40°C to 100°C. Such membranes can also be handled using pick and place machines, which allows an arrangement with high precision, which is a further advantage in terms of production technology. Kapton in particular is also ROHS and IATF certified. Kapton can be supplied in a number of membrane thicknesses, coatings and colors so that additional desired properties can be easily implemented in manufacturing technology.

Additionally or alternatively, the membrane can have a polyester, in particular a biaxially oriented polyester, in particular a biaxially oriented polyethylene terephthalate (BOPE), for example Mylar, or be formed from it. Polyesters of this type, in particular BOPE, in particular Mylar, are resistant to chemicals and waterproof in accordance with protection classes IP69 or IP69K. Such membranes also have a high tensile strength (4 GPa), with such a membrane retaining its flexibility. Maintaining flexibility serves to prevent or at least minimize damping of the mechanical sound transmission energy. Tensile strength serves to prevent or at least minimize loss of resonance. Such membranes and in particular Mylar also have good temperature resistance, in particular in a range from -70°C to 150°C, which means that they remain constant over the required temperature range of -40°C to 100°C has mechanical properties. Such membranes can usually also be handled by means of pick and place machines, which allows an arrangement with high precision, which is a further advantage in terms of production technology. Mylar in particular is also ROHS and IATF certified. Mylar can also be provided in a variety of membrane thicknesses, coatings and colors so that additional desired properties can be easily implemented in terms of production technology.

Additionally or alternatively, the membrane can be impermeable to air and/or coatable, in particular paintable, and/or pressure-resistant, in particular up to a pressure of 10,000 kPa and/or temperature-resistant in a temperature range from -269 °C to 400 °C, in particular in a Temperature range from -70 °C to 150 °C, in particular in a temperature range from -40 °C to 100 °C. An airtight membrane is particularly advantageous because it is particularly easy to coat, in particular to paint, since the penetration of aerosols during coating or painting can be reliably avoided in a structurally simple manner. The membrane is preferably made of the same material.

The membrane can be provided with a conductive coating. A charge can be introduced into the membrane by a conductive coating on a PCB side, in particular on a side facing away from the sound transducer. If a charge is applied to the membrane, a plate capacitor can be formed with a static counter-electrode, which changes its capacitance in direct proportion to the deflection by incoming sound waves (capacitor microphone principle) or a transmitter can be constructed by repelling charges (electrostatic loudspeaker principle). If a neutral charge is introduced, the membrane can serve as a shield against electrical fields and divert electrostatic discharges from the actual transducer.

In one embodiment, the sound transducer device can have at least one cover layer and/or at least one spacer layer and/or at least one adhesive layer. A top layer is a layer that faces the environment directly. The surface layer is exposed to the sound pressure waves from the surrounding area. A spacer layer is understood to mean a layer which is arranged between the cover layer and the substrate. The cover layer can be arranged on at least one spacer layer and/or at least one adhesive layer. The provision of one or more spacer layers offers the advantage that the dimensions of the sound transducer device can be adjusted in the thickness direction of the substrate in order to easily adapt the sound transducer device to the spatial conditions in the application device, for example. This is particularly advantageous because the substrates are often available in standardized sizes and therefore an adjustment in the direction of thickness is not possible or is very expensive. The cover layer can have an adhesive layer. The adhesive layer can be ring-shaped and can enclose the sound opening.

The spacer layer can have a cavity in the area of the sound opening. The cavity can have a round or elliptical shape in cross section, in particular transverse to the thickness direction of the substrate. A cavity cross section can be designed to be the same as a sound opening cross section. Alternatively, the cavity cross section can be larger than the sound opening. The cavity can be fluidly connected to the sound channel. In particular, the cavity can be arranged coaxially to the sound channel.

If several spacer layers are provided, the cavity cross sections of the individual spacer layers can differ from one another. This is particularly necessary when the top layer has a convex shape, as described in more detail below. The at least one spacer layer and the cover layer can consist of the same material. The provision of one or more cavity spacer layers also offers the advantage that the acoustic space can easily be adjusted in order to obtain the desired resonant frequency range.

In an alternative embodiment, the spacer layer can have no cavity in the area of the sound opening. By providing one or more spacer layers without a cavity, a resonance damping behavior of the acoustic space can be adjusted in a simple manner. The at least one spacer layer may include an adhesive layer. The adhesive layer can be designed as an annular adhesive layer.

The ring-shaped arrangement of the adhesive layer in the cover layer and/or the spacer layer around the sound opening has the additional advantage that the adhesive layer is easy to produce in terms of manufacturing technology.

In one embodiment, the membrane can have a thickness of 0.01 to 0.1 mm (millimeter), in particular a thickness of 0.02 to 0.05 mm, in particular a thickness of 0.05-0.03 mm. This has the advantage that the membrane allows for good sound transmission in a structurally simple manner. A modulus of elasticity of the membrane can particularly preferably be between 1.5 and 4 GPA, in particular 1.7-3.5 GPA. This range is particularly advantageous for flexibility and tensile strength of the membrane.

The layer or layers of the membrane can be chosen in size and shape according to the requirement of the desired application. In order to reliably comply with the protection classes IP69 or IP69K, it is advantageous to position the membrane with an accuracy of at least 0.1 mm relative to the sound opening.

In a special embodiment, the sound transducer device can have a membrane with at least one adhesive layer, with at least one adhesive layer connecting the membrane to the substrate, in particular the control device. This has the additional advantage that the sound transducer device has a particularly simple design. The at least one adhesive layer can preferably form an adhesion area of the membrane with the substrate.

Particularly preferably, the membrane can have no adhesive layer in a sound-transmitting area of the membrane. This has the additional advantage that the area weight of the membrane is reduced in this area compared to an embodiment in which the sound-receiving area of the membrane has an adhesive layer. This is advantageous with regard to sound transmission through the membrane.

In one embodiment, the membrane can be concave or convex or flat, with the concave, convex or flat part of the membrane carrying the sound Area of the membrane includes. A concave or convex design of the membrane, in particular of the cover layer, improves the acoustic sensitivity of the sound transducer device. The acoustic sensitivity depends on the area and geometry of the sound-transmitting area. As a result, the sound transducer device can be designed in a structurally simple manner in an optimized manner depending on the desired properties.

With a convex configuration of the membrane, in particular the cover layer, the spacer layer can have a cavity cross section that is larger than the sound opening cross section. When multiple spacer layers are provided, the cavity cross-section of the spacer layer may increase in a direction from the substrate to the cap layer. This means that the individual spacer layers have different cavity cross sections. With a convex configuration of the membrane, a part of the membrane that has the sound-transmitting region protrudes from the remaining part of the membrane in a direction away from the substrate.

In a special embodiment, the course of the sound channel between the end facing the sound transducer and the other end of the sound channel facing the membrane cannot be constant. In particular, the sound channel can have a cross section that changes along the thickness direction of the substrate. In this case, the cross section of the sound channel can narrow along the thickness direction of the substrate. In particular, the course of the cross section can decrease starting from the other end of the sound channel in the direction of the end of the sound channel, ie in the direction of the sound transducer.

The course of the cross section can be axisymmetric, in particular conical, concave, funnel-shaped and/or step-shaped axisymmetric. Alternatively, the cross-sectional constriction can also be non-axially symmetrical. It is particularly advantageous if the cross section narrows, starting from the membrane in the direction of the sound transducer. This achieves an increase in pressure within the sound channel, which improves the sensitivity of the sound transducer device. In particular, such an embodiment is advantageous in which the sound opening and thus the membrane surface used for sound transmission is not large, and thus little sound energy is transmitted into the sound channel. The sound opening and the membrane area However, they cannot be increased arbitrarily, because in this case the acoustic space has to be reduced in order to obtain a specified resonance frequency range. However, reducing the acoustic space is not always possible.

The sound channel can have at least two sections, a first section having a cross section that changes along the thickness direction. In particular, the cross section decreases in a direction starting from the membrane in the direction of the sound transducer. A second section, which can directly adjoin the first section, can have a constant cross section. The second section can be directly connected to the sound transducer.

An area ratio of an area of the other end of the sound channel, which faces the membrane, to an area of the end of the sound channel, which faces the sound transducer (2), can be between 1.5 and 10, preferably between 3 and 8, in particular 6:25, be. The surface of the other end of the sound channel can correspond to a surface of the sound opening. The end of the sound channel facing the sound converter opens into the interior of the sound converter.

In a further embodiment of the sound transducer device, a sound channel medium can have the same or different density than an external medium, in particular air, or can form a different phase. This has the additional advantage that the sound is received by the sound transducer in an optimized manner since little or no phase loss occurs. Such losses are caused by the phase transition between different media (gas, membrane, gas, sound transducer). The sound channel medium can preferably include or be air or a non-compressible liquid, in particular an oil, in particular a mineral oil. In addition, the sound channel medium can have a different pressure compared to the surrounding atmosphere.

According to a further aspect of the invention, a method for producing a sound transducer device according to the invention comprising a substrate and a sound transducer which is acoustically connected to one end of a sound channel of the substrate, characterized in that the sound transducer device has a watertight acoustic membrane which another end of the sound channel covers, provided comprising a step of arranging the membrane on the substrate, wherein the membrane covers a sound channel of the substrate.

The method can optionally have a further step in which the sound transducer is connected to a side of the substrate opposite the membrane. The method according to the invention can optionally include the step that the membrane is arranged, in particular fastened, on the substrate by means of at least one adhesive layer.

The method according to the invention can optionally include the step that the membrane is arranged, in particular fixed, on the substrate by means of a soldering method or a reflow method. In addition, the sound transducer can be attached to the substrate by means of a soldering process. Optionally, the method according to the invention can have a further step in which the at least one cover layer is applied to at least one spacer layer.

The method according to the invention can optionally include a step in which one surface of the membrane is provided with at least one adhesive layer, in particular the entire surface of the membrane. Alternatively, the at least one adhesive layer can be applied in such a way that a predetermined area of the membrane is free of the adhesive layer, in particular a sound-transmitting area of the membrane.

In addition or as an alternative, the method according to the invention can have a step in which the at least one adhesive layer is applied in an adhesion area of the membrane, in particular is applied in a ring shape.

Additionally or alternatively, the method according to the invention can have a step in which the at least one adhesive layer is applied before a step of assembling the membrane.

In addition or as an alternative, the method according to the invention can have a step in which the at least one adhesive layer is applied in a predetermined amount, in particular, for example, to set a predetermined signal-to-noise ratio of the sound transducer device. According to a further aspect of the invention, a position determination device is provided, comprising a sound transducer device according to the invention.

According to a further aspect of the invention, a sound transducer device according to the invention or a position determination device in a motor vehicle, in particular for autonomous driving, and/or in a communication system and/or in a microphone application and/or in an industrial application and/or in applications for collision avoidance and/or or devices for presence detection are used. In addition, the sound transducer device according to the invention can be used for noise localization and/or for a predictive maintenance application and/or for a distance measurement and/or a filling level measurement.

The position determination device can be used for one-dimensional or multi-dimensional, preferably three-dimensional, position determination. At least one sound transducer device or several sound transducer devices can be used for position determination. In this case, a sound transducer device can function as a transmitter. In addition, at least one, in particular exactly three, sound transducer devices can act as receivers. In particular, an embodiment is conceivable in which several sound converters, in particular three sound converters, are arranged on the same printed circuit board. In this case there is only one sound transducer device for determining the 3D position. Alternatively, one sound transducer can be arranged on each printed circuit board. In this case there are several sound transducer devices.

For three-dimensional position determination, the transmitter and one receiver or two receivers can lie on a straight line. The third receiver is arranged in such a way that it is not arranged on the straight line. The transmitter and all receivers lie in a plane that has the straight line. The object whose position is to be determined is arranged such that it is spaced apart from the plane. In other words, the object is not arranged in the plane. The transmitter can act as one of the receivers after sending out the transmission signal. This means that the transmitter can both transmit the broadcast signal and receive signals. One arranged on the Printed Circuit Board Data processing unit, in particular at least one processor, can calculate the position in space, in particular a position in three-dimensional space, on the basis of the received signals.

The subject matter of the invention is shown schematically in the figures, with identical or similarly acting elements generally being provided with the same reference symbols.

Figures 1A-B show a schematic representation of a sound transducer device according to a first embodiment.

Figures 2A-B show a schematic representation of a sound transducer device according to a second embodiment.

Figures 3A-B show a schematic representation of a sound transducer device according to a third embodiment.

Figures 4A-B show a schematic representation of a sound transducer device according to a fourth embodiment.

Figures 5A-B show a schematic representation of a sound transducer device according to a fifth embodiment.

Figures 6A-B show a schematic representation of a sound transducer device according to a sixth embodiment.

Figures 7A-B show a schematic representation of a sound transducer device according to a seventh embodiment.

Figures 8A-B show a schematic representation of a sound transducer device according to an eighth embodiment.

FIG. 9 shows a schematic representation of a sound transducer device according to a ninth exemplary embodiment. FIG. 10 schematically shows the mode of operation of a sound transducer device according to the invention.

FIGS. 1A-B show a sound transducer device 1. FIG. 1B shows a highlighted detail 25 from FIG. The sound transducer device 1 includes a sound transducer 2 which is acoustically connected to one end 16 of the sound channel 12 of a substrate 17 . The sound converter 2 has a sound converter housing 28 and a sound receiver and/or sound transmitter 3 which is arranged in an interior space 19 of the sound converter 2 . The interior space 19 is delimited by the sound transducer housing 28 and the substrate 17 . The sound converter 2 is arranged below the substrate 17 in the installation direction E of the sound converter device 1 .

The sound channel 12 has another end comprising a sound opening 4, whereby sound pressure waves pass through the sound opening 4 before reaching the sound transducer 2, as will be described in more detail below. The sound channel 12 extends through the entire thickness of the substrate 17. The extension of the substrate 17 between a substrate side facing the surroundings and a substrate side facing the sound transducer 2 is understood as thickness. The thickness corresponds to the extension of the substrate 17 along the z-direction of the coordinate system shown in Fig. 1A and/or an extension between the end 16 and the inlet opening 4.

The sound transducer device 1 has a waterproof acoustic membrane 5 which completely covers the sound channel 12 . In particular, the membrane 5 covers the sound opening 4 . The membrane 5 is arranged on a side of the substrate 17 directed towards an environment and comprises a cover layer 6 and an adhesive layer 11, the adhesive layer 11 covering the cover layer 6 of the membrane 5 completely. The membrane 5 is arranged, in particular glued, on the substrate 17 by means of the adhesive layer 11 . The substrate 17 is, for example, a control device, for example a printed circuit board. The membrane 5 has two areas, a sound-transmitting area 23 and an adhesion area 24. The sound-transmitting area 23 is the section of the membrane 5 that vibrates when the membrane 5 is subjected to a sound wave, so that sound energy is transmitted into the sound channel 12. As can be seen from FIGS. 1A and 1B, the sound-transmitting area is arranged in the area of the sound channel 12 . In particular, a cross section of the sound-transmitting area can correspond to a sound opening cross section 9 .

The sound transducer device 1 also has an acoustic space 18 . The acoustic space 18 is a closed space composed of the interior space 19 of the sound transducer 2 and the sound channel 12 . A resonance damping behavior of the sound transducer device 1 depends on the thickness and/or the material and/or the prestressing of the membrane 5 and the adhesive layer 11 present in the sound-transmitting region 23 of the membrane 5 . A resonance frequency behavior, in particular a resonance frequency range, of the sound transducer device 1 depends on the volume of the acoustic space 18 . An acoustic sensitivity of the sound transducer device 1 depends, among other things, on the area and the geometry of the cover layer 6 located in the area of the sound channel 12.

FIGS. 2A-B show a second embodiment, only the differences from the first embodiment being discussed below. The second embodiment differs from the first embodiment in that the membrane 5 has no adhesive layer 11 in the sound-transmitting region 23 . As a result, the mass of the sound-transmitting area 23 of the sound transducer device 1 is reduced.

Since there is no adhesive layer 11 on the sound-transmitting area 23 in the embodiment, the resonance damping behavior of the acoustic space 18 depends on the thickness and/or the material and/or the prestressing of the membrane 5 . On the other hand, in the first embodiment, the resonance damping behavior of the acoustic space 18 depends on the diaphragm 5 and the adhesive layer 11. The resonance frequency behavior, in particular a resonance frequency range, depends on the volume of the acoustic space 18 . The acoustic sensitivity of the sound transducer device 1 depends, among other things, on the area and the geometry of the sound-transmitting area 23.

Figures 3A-B show a third embodiment. The third embodiment differs from the first embodiment shown in FIGS Adhesive layer 1 1 is arranged. In particular, the cover layer 6 is firmly connected to the spacer layer 7 by means of the adhesive layer 11 . The adhesive layer 11 is distributed evenly over the entire underside of the cover layer 6. The spacer layer 7 is arranged on the substrate 17 and is firmly connected to the substrate 17 by means of a further adhesive layer 11 . As a result, the spacer layer 7 is arranged between the cover layer 6 and the substrate 17 as seen in the z-direction.

The spacer layer 7 differs from the cover layer 6 in that it has a cavity 10 in the area of the sound opening 4 . The cavity 10 is arranged coaxially with the sound channel 12 . In contrast, the cover layer 6 has the sound-transmitting area 23 in the area of the sound opening 4 . Such a formation of the spacer layer 7 results in the volume of the acoustic space 18 being larger by the volume of the cavity 10 in comparison to the first embodiment.

Analogously to the first embodiment shown in FIGS. 1A, 1B, the resonance damping behavior of the acoustic space 18 depends on the thickness of the cover layer 6 in the z-direction and the applied adhesive layer 11.

Figures 4A-B show a fourth embodiment. The fourth embodiment differs from the third embodiment in the design of the membrane 5, in particular the cover layer 6 and the spacer layer 7. The cover layer 6 is concave in the area of the sound opening 4. FIG. The concave part of the cover layer 6 includes the sound-transmitting area 23. The spacer layer 7 has a cavity 10 in the area of the sound opening 4, the cross section of which is larger than the sound opening cross section 9. The concave depression 22 resulting from the concave design of the cover layer 6 has an effect favorably on the acoustic sensitivity of the sound transducer device 1 from. As already explained above, the acoustic sensitivity of the sound transducer device 1 depends on the area and the geometry of the cover layer 6 located in the area of the sound channel 12 .

Figures 5A-B show a fifth embodiment. The fifth embodiment differs from the fourth embodiment in the attachment of the adhesive layer 1 1 to the cover layer 6. Although the adhesive layer 1 1 is evenly distributed on the underside of the cover layer 6, there is a difference in that the adhesive layer 1 1 in the area the Sound hole 4 is designed as a circular ring. This ensures a permanent connection.

The adhesive layer 11 is applied to the layers of the membrane 5 before assembly and serves to form more stable and lighter assemblies.

Figures 6A-B show a sixth embodiment. The sixth embodiment differs from the third embodiment shown in FIGS. 3A, 3B in the design of the membrane 5. The membrane 5 has two spacer layers 7 which are arranged one above the other and are fastened to one another by means of an adhesive layer 11. The spacer layer 7 that is further away from the substrate 17 has a larger cavity cross section than the spacer layer 7 arranged on the substrate 17. This allows the cover layer 6 to be concave in the area of the sound channel 12.

The cover layer 6 is firmly connected to the spacer layer 7 directly attached to the substrate 17 by means of an annular adhesive layer 11 . The sound-transmitting area 23 of the membrane 5 covering the sound opening 4 has no adhesive layer 11.

FIGS. 7A-B show a seventh embodiment of a sound transducer device 1 . The seventh embodiment differs from the sixth embodiment in the design of the membrane 5. Thus, the seventh embodiment has a total of five spacer layers 7, while the sixth embodiment has two spacer layers 7.

Two spacer layers 7 are formed in such a way that their respective cavity 10 increases the volume of the acoustic space 18 . In particular, the cavity cross section of the respective spacer layer 7 corresponds to the sound opening cross section 9. These are the two spacer layers that are assigned closer to the substrate 17 than the remaining spacer layers 7. The remaining spacer layers have a cavity cross section that is larger than the sound opening cross section 9. The cavity cross section increases along a direction from the substrate 17 in the direction of the cover layer 6. In the present embodiment, since three spacer layers 7 differ in cavity cross-section from hole cross-section, the concave recess 22 of the cover layer has a larger volume than the concave recess 22 of the sixth embodiment.

Another difference is that there is no annular adhesive layer 11 connecting the cover layer 6 to a spacer layer 7 . The adhesive layer 11 is evenly distributed over the entire cover layer 6, with the exception of the sound-transmitting area 23.

The acoustic space 18 is larger in the seventh embodiment than in the sixth embodiment. This results from the fact that there are two spacer layers 7 each having a cavity 10 , whereas in the sixth embodiment there is one spacer layer 7 whose cavity 10 forms part of the acoustic space 18 .

Figures 8A-B show an eighth embodiment. The eighth embodiment differs from the third embodiment in the design of the membrane 5. In particular, the cover layer 6 has a convex shape in the area of the sound opening 4, ie at least a part of the membrane 5 encompassing the sound-transmitting area 23. This is made possible by applying additional adhesive layers 11 to the layers of the membrane 5 and/or applying ring-shaped adhesive layers 11, which in each case firmly connect the cover layer 6 to the spacer layer 7. Due to the convex design of part of the membrane 5, the acoustic space 18 increases in comparison to the third embodiment shown in FIGS. 3A, 3B.

The convex formation of the cover layer 6 can take place in that the sound transducer device 1 is assembled under high pressure. It is therefore possible to create convex shapes by assembling the acoustic transducer device under high air pressure. The air trapped in the sound duct 12 expands in the normal atmosphere and forms convex bubbles. In another embodiment where a sound passage medium other than air is placed in the sound passage, a convex bubble can be achieved by cooling or heating the sound passage medium. A sound transducer device 1 designed in this way enables better sensitivity to sound pressure waves that arrive at a steep angle.

FIG. 9 shows a ninth embodiment. The ninth embodiment differs from the first embodiment in the design of the sound channel 12. Thus, the sound channel 12 in the ninth embodiment has two sections. A first section, which extends from the sound opening 4 in the direction of the sound transducer 2, has a cross section that decreases along a thickness direction of the substrate. The cross section refers to a plane that is normal to the z-direction. In contrast, a second section directly adjoining the first section has a constant cross section along the thickness direction. The second section thus extends from the transition area with the first section to the end 16 of the sound channel 12. An area ratio of a surface of the sound opening 4, which corresponds to a surface of the other end of the sound channel 12, to a surface of the other end 16 of the sound channel 12 is between 1.5 and 10, in particular 6.25.

FIG. 10 shows schematically how a sound transducer device 1 works. In FIG. 10, the cover layer 6 of the membrane 5, in particular a part of the membrane 5 encompassing the sound-transmitting region 23, is concave. However, each of the previously described sound transducer devices 1 has the mode of operation described below.

Sound pressure waves 27 from the surroundings of the sound transducer device 1 impinge on the membrane 5, which causes the membrane 5, in particular the sound-transmitting region 23, to vibrate. This is symbolized in FIG. 10 by the double arrow. In other words, the pressure energy of the sound pressure waves is transferred into kinetic energy of the diaphragm 5. The sound energy transmitted to the membrane 5 is transmitted into the sound channel 12 .

A distinction must be made with which sound channel medium 13 the sound channel 12 is filled. In the event that the sound channel 12 is filled with a compressible fluid such as air, the vibration of the membrane 5 generates sound pressure waves in the sound channel 12, which pass through the sound channel 12 and reach the interior space 19 of the sound transducer 2 and from the sound receiver 3 are recorded. If an incompressible fluid, such as a liquid, is arranged in the sound channel 12 , the vibration of the membrane 5 is transmitted directly to the sound transducer 2 , in particular the sound receiver 3 . In the exemplary embodiment illustrated in FIG. 10, a liquid is arranged in the sound channel 12, which is symbolized by the gray shading of the sound channel 12.

REFERENCE LIST

1 sound transducer device

2 sound converters

3 sound receivers and/or transmitters

4 sound port

5 membrane

6 top layer

7 spacer layer

9 sound opening cross section

10 cavity

1 1 adhesive layer

12 sound channel

13 media

16 end of sound canal

17 substrate

18 acoustic space

19 interior

22 concave depression

23 sound transmitting area

24 adhesion area

25 highlighted area

27 sound pressure waves

28 transducer housing

E installation direction

Claims

23 CLAIMS

1 . Sound transducer device (1) comprising a substrate (17) and a sound transducer (2) which is acoustically connected to one end (16) of a sound channel (12) of the substrate (17), the sound transducer device (1) having a waterproof acoustic membrane (5 ) which covers another end of the sound channel (12), characterized in that the substrate (17) is a printed circuit board.

2. Sound transducer device (1) according to claim 1, characterized in that a. the membrane (5) is firmly connected to the substrate (17) and/or that b. the membrane (5) is arranged, in particular glued, on the substrate (17).

3. Sound transducer device (1) according to claim 1 or 2, characterized in that the other end of the sound channel (12) comprises a sound opening (4).

4. Sound transducer device (1) according to any one of claims 1 to 3, characterized in that the sound transducer (2) and the membrane (5) are arranged on opposite sides of the substrate (17).

5. Sound transducer device (1) according to one of claims 1 to 4, characterized in that the sound transducer device (1) is configured such that a sound pressure wave passes through the sound channel (12) before it is received by the sound transducer (2).

6. sound transducer device (1) according to any one of claims 1 to 5, characterized in that a. the membrane (5) closes off an acoustic space (18) composed of the sound channel (12) and an interior space (19) of the sound transducer (2), and/or that b. an acoustic space (18), which is composed of the sound channel (12) and an interior (19) of the sound transducer (2), is completely closed off by the membrane (5) and a sound transducer housing (28).

7. sound transducer device (1) according to any one of claims 1 to 6, characterized in that a. the sound transducer (2) has an interior space (19) which is at least partially enclosed by a sound transducer housing (28) and is acoustically connected to the sound channel (12), and/or that b. the sound converter (2) has a sound receiver and/or transmitter (3) which is arranged in an interior (19) of the sound converter (2).

8. sound transducer device (1) according to any one of claims 1 to 7, characterized in that the membrane (5) a. comprises or is formed from a polyimide, in particular a thermoset polyimide, in particular poly(4,4'-oxydiphenylene-pyromellitimide); and/or b. comprises or is formed from a polyester, in particular a biaxially oriented polyester, in particular a biaxially oriented polyethylene terephthalate, and/or c. impermeable to air and/or coatable, in particular paintable, and/or pressure-resistant, in particular up to a pressure of 10,000 kPa and/or temperature-resistant in a temperature range from -269 °C to 400 °C, in particular in a temperature range from -70 °C to 150 °C, in particular in a temperature range from -40 °C to 100 °C.

9. sound transducer device (1) according to any one of claims 1 to 8, characterized in that the membrane (5) a. has a cover layer (6) and/or b. has at least one spacer layer (7) and/or c. has at least one adhesive layer (1 1).

10. Sound transducer device (1) according to claim 9, characterized in that a. the cover layer (6) is arranged on at least one spacer layer (7) and/or adhesive layer (11), and/or b. the cover layer (6) has an adhesive layer (11), in particular an annular adhesive layer (11), and/or c. the at least one spacer layer (7) has a cavity (10) which is fluidically connected to the sound channel (12), and/or d. the at least one spacer layer (7) has an adhesive layer (11), in particular an annular adhesive layer (11).

1 1. Sound transducer device (1) according to one of claims 1 to 10, characterized in that the membrane (5) has a thickness of 0.01 to 0.1 mm, in particular a thickness of 0.02 to 0.05 mm, in particular a thickness of 0.05 - 0.03 mm.

12. Sound transducer device (1) according to one of claims 1 to 11, characterized in that a modulus of elasticity of the membrane (5) is between 1.5 and 4 GPA, in particular between 1.7-3.5 GPA.

13. Sound transducer device (1) according to one of claims 1 to 12, characterized in that an area ratio of an area of the other end of the sound channel (12), which faces the membrane (5), to an area of the end of the sound channel (12) , which points to the sound transducer (2), is between 1.5 and 10.

14. Sound transducer device (1) according to any one of claims 1 to 13, characterized in that the membrane (5) has at least one adhesive layer (1 1), wherein the at least one adhesive layer (1 1) the cover layer (6) with the substrate ( 17) and/or the spacer layer (7) and/or connects the spacer layer (7) to the substrate (17).

15. Sound transducer device (1) according to claim 14, characterized in that the at least one adhesive layer (11) forms an adhesion region (24) of the membrane (5).

16. Sound transducer device (1) according to claim 14 or 15, characterized in that the membrane (5) has no adhesive layer (11) in a sound-transmitting region (23).

17. Sound transducer device (1) according to claim 14 to 16, wherein the at least one adhesive layer (11) is arranged in a ring around the sound opening (4). 26

18. Sound transducer device (1) according to one of claims 1 to 17, characterized in that the membrane (5), in particular a sound-transmitting region (23) of the cover layer (6), is concave or convex or flat.

19. Sound transducer device (1) according to any one of claims 1 to 18, characterized in that a. a cross section of the sound channel (12) changes along a thickness direction of the substrate (17) and/or b. the sound channel (12) has two sections, a first section having a cross-sectional constriction along the thickness direction of the substrate (17), and a second section having a constant cross-section along the thickness direction of the substrate.

20. Sound transducer device (1) according to one of claims 1 to 19, characterized in that a sound channel medium (13) has a density which is the same as or different from an external medium or forms a different phase.

21 . Sound transducer device (1) according to claim 20, characterized in that the sound channel medium (13) a. is air or b. has or is a liquid, in particular a non-compressible liquid, in particular an oil, in particular a mineral oil.

22. A method for producing a sound transducer device (1) according to any one of claims 1 to 21, comprising a step of arranging a membrane (5) on a substrate (17), wherein the membrane (5) has a sound channel (12) of the substrate (17 ) covers.

23. The method of claim 22; characterized in that the method comprises a step in which an acoustic transducer (2) is connected to a side of the substrate (17) opposite the membrane (5).

24. The method according to claim 22 or, characterized in that the cover layer (6) and/or the spacer layer (7) is arranged, in particular fastened, on the substrate (17) by means of at least one adhesive layer (11). 27

25. The method as claimed in one of claims 22 to 24, characterized in that the membrane (5) is arranged, in particular fastened, on the substrate (3) by means of a soldering process or a reflow process.

26. The method according to any one of claims 22 to 24, characterized in that the cover layer (6) is applied to at least one spacer layer (7).

27. The method according to any one of claims 22 to 26, characterized in that a. a surface, in particular the entire surface, of the cover layer (6) and/or the spacer layer (7) is provided with at least one adhesive layer (11), and/or b. the at least one adhesive layer (11) is applied in such a way that a predetermined area of the membrane (5) is free of the adhesive layer (11), in particular a sound-transmitting area (23) of the membrane (5), and/or c. the at least one adhesive layer (11) is applied in an adhesion area (24) of the membrane (5), in particular applied in a ring shape, and/or d. the at least one adhesive layer (11) is applied before an assembly step of the membrane (5), and/or e. the at least one adhesive layer (1 1) is applied in a predetermined amount.

28. Position determination device having at least one sound transducer device (1) according to any one of claims 1 to 21.

29. Use of a sound transducer device (1) according to any one of claims 1 to 21 or a position determination device according to claim 28 for one-dimensional or multi-dimensional, preferably three-dimensional, position determination.