Acoustic device having pressure compensation

Abstract

The invention relates to an acoustic device having a housing, wherein: the housing has an opening which leads into an interior of the housing; the opening is closed by a first membrane; the interior of the housing has a first and a second space; the first space is connected to the opening of the housing; a sensor for receiving a pressure signal and / or an actuator for generating a pressure signal is arranged in the first space; the first membrane is designed to transmit pressure fluctuations between the first space and an environment outside the housing; a second membrane is provided; the second membrane is adjacent to at least the first space and the second space; the second membrane has a predetermined air permeability and allows for pressure compensation between the first and the second space; the pressure compensation is slower than a predetermined value; and the second space is connected to an environment outside the housing via a pressure compensation element.

Description

[0001] Description

[0002] title

[0003] Acoustic device with pressure compensation

[0004] The invention relates to an acoustic device comprising a sensor and / or an actuator arranged in a first chamber of the device. The first chamber is connected to a second chamber via a pressure-equalizing membrane.

[0005] State of the art

[0006] From US 10,911,847 B2 an acoustic device with a housing is known, wherein the housing has an opening that leads into an interior of the housing. The opening is closed with a first membrane. The first membrane is hermetically sealed and serves to transmit pressure fluctuations between the first chamber and the environment of the housing. A first and a second chamber are formed in the interior of the housing, wherein the first chamber is connected to the opening of the housing. A sensor for recording the pressure signal and / or an actuator for generating a pressure signal is arranged in the first chamber. A second membrane is provided between the first chamber and the second chamber. The second membrane has a predetermined air permeability in order to enable pressure equalization between the first and second chambers.

[0007] Disclosure of the invention

[0008] The object of the invention is to provide an improved acoustic device.

[0009] The object of the invention is achieved by the device according to claim 1. Embodiments of the device are specified in the dependent claims.

[0010] An acoustic device with a housing is proposed, wherein the housing has an opening, wherein the opening leads into an interior of the housing. The opening is closed with a first membrane. The interior of the housing has a first and a second chamber. The first chamber is connected to the opening of the housing. A sensor for recording a pressure signal and / or an actuator for generating a pressure signal is arranged in the first chamber. The sensor can be a pressure sensor or a sound sensor. The actuator can be provided, for example, to generate acoustic signals. Thus, the acoustic device can represent a loudspeaker and / or a microphone. The first membrane is designed to transmit pressure fluctuations between the first chamber and an environment outside the housing. The first membrane is preferably designed to be air-impermeable.The first membrane can be a non-porous membrane to prevent moisture or liquid from penetrating the first space. A second membrane is provided between the first space and the second space. The second membrane has a predetermined air permeability to enable slow pressure equalization between the first and second spaces. The pressure equalization is slower than a predetermined value so as not to impair the functionality of the actuator and / or the sensor. The second membrane can, for example, be designed to allow less than 500 mL / min of air to pass through. The air permeability of the second membrane is preferably so low that short-term pressure fluctuations in the first space are not or hardly dampened. The second space is preferably connected to an environment outside the housing via a pressure equalization element.Thus, the pressure equalization element allows for rapid pressure equalization between the ambient air and the second room. This provides an acoustic device with improved pressure equalization functionality.

[0011] In one embodiment, the second membrane is arranged between the first membrane and the sensor and / or the actuator. The second membrane covers the entire cross-section of the first space. In addition, the second membrane is led into the second space with a lateral edge region. Due to the air permeability of the second membrane, a correspondingly slow pressure equalization between the first space and the second space can be achieved via the edge region. This embodiment has the advantage that the second membrane is easy to install and, moreover, the second membrane protects the actuator and / or the sensor in addition to the first membrane. This increases safety. Even if the first membrane is damaged and moisture or dirt can penetrate into the first space, the actuator and / or the sensor will continue to be protected by the second membrane.

[0012] In a further embodiment, a first section of the first space can be formed by a sealing ring. A second section of the first space is formed by a continuous channel of a carrier plate. The sensor and / or actuator are adjacent to the channel. The channel is sealed from the second space. The sealing can be achieved, for example, by the sensor and / or the actuator. The second membrane is arranged between the opening and the carrier plate. The second membrane projects into the second space with a lateral edge region. The sealing ring can be arranged between the housing and the carrier plate. In this way, a simple, robust, and inexpensive to manufacture device is provided. In addition, the design is compact because the carrier plate, which is designed, for example, as a printed circuit board and has electrical lines and / or electrical or electronic circuits, delimits a section of the first space.

[0013] In a further embodiment, the second membrane is mechanically firmly and preferably tightly connected to a bottom side of the sealing ring by a first adhesive layer and / or to a top side of the carrier plate by a second adhesive layer. This allows the device to be manufactured simply and cost-effectively.

[0014] In a further embodiment, a connecting channel is incorporated into the housing. The connecting channel extends from the second chamber to the first chamber. The connecting channel is closed with the second membrane. In this way, the arrangement of the second membrane is possible independently of the geometry and the arrangement of the first chamber. This achieves increased flexibility in selecting the device's geometry. In addition, a pressure equalization rate can be determined independently of the second membrane, preferably via the dimensioning of the connecting channel, i.e., the length and / or cross-section of the connecting channel.

[0015] In a further embodiment, the first membrane is attached to an outer side of the housing. The attachment can be achieved, for example, using an adhesive layer. The connecting channel runs from an inner side of the housing to an outer side of the housing. Furthermore, the connecting channel is connected to the first chamber via a first channel opening, which is covered by the second membrane. This results in a simple housing design. By arranging the first channel opening on the outer side of the housing, the second membrane can be easily and precisely attached and secured to the housing over the first channel opening.

[0016] In a further embodiment, the first channel opening is arranged on an outer side of the housing and below the first membrane, spaced apart from the first membrane. The second membrane is arranged between the outer side of the housing and the first membrane. This arrangement enables easy assembly of the first membrane and the second membrane on the housing.

[0017] In a further embodiment, the first channel opening opens into a recess in the outside of the housing. The recess opens laterally into the opening in the housing. The second membrane is arranged in the recess. The first membrane covers the opening and the recess. By providing the recess, the second membrane can be reliably mounted. In addition, by designing the height of the recess, the actual air permeability of the second membrane can be adjusted. If, for example, the second membrane rests on the underside of the first membrane, the cross-section for air exchange between the connecting channel and the first space is determined by the thickness of the second membrane. However, if the recess has a greater depth than the thickness of the second membrane, a larger effective area of ​​the second membrane is available for air exchange.

[0018] The actuator is used, for example, to generate sound signals. Thus, the device can represent a loudspeaker. The sensor can also be designed to detect a pressure signal and / or a sound signal. Thus, the sensor can be designed to detect pressure or as a microphone for detecting sound.

[0019] In one embodiment, a protective cover is arranged on the outside of the housing over the first membrane. The protective cover protects the first membrane from mechanical damage.

[0020] The invention is explained in more detail below with reference to the figures.

[0021] Figure 1 shows a schematic cross section through a first embodiment of a device,

[0022] Figure 2 is a schematic and enlarged partial view of the device of Figure 1,

[0023] Figure 3 is a schematic and enlarged partial view of another embodiment of Figure 1,

[0024] Figure 4 is a schematic plan view of the arrangement of Figure 3.

[0025] Figure 5 shows a schematic cross section through a further embodiment of the device, and

[0026] Figure 6 shows a schematic plan view of a partial section of the arrangement in Figure 5. Figure 1 shows a schematic sectional view of a cross section through a device 1 which has a housing 2. The housing 2 defines a cuboid-shaped interior space 3 with six side walls. A first space 4 and a second space 5 are arranged in the interior space 3. The housing 2 has an opening 6 on an upper side wall 29 which leads from an outer side of the housing to the interior space. The opening 6 is closed with a first membrane 7 which, in the illustrated embodiment, is arranged on the upper side of the side wall of the housing 2. The first membrane 7 can, for example, be attached to the upper side of the side wall of the housing 2 via a third adhesive layer 18. The third adhesive layer 18 can be formed in a ring around the opening 6.

[0027] The first membrane 7 is essentially airtight and flexible in such a way that pressure fluctuations, such as acoustic signals, are transmitted from the outside of the housing via the first membrane 7 to the opening 6 and thus to the first chamber 4. In the same way, pressure fluctuations from the first chamber 4 are emitted to the environment via the opening 6 and the first membrane 7. In the illustrated embodiment, the first chamber 4 directly borders the opening 6.

[0028] In the illustrated embodiment, the first chamber 4 is delimited in a first section by a component, for example, a seal 8. The seal 8 is designed, for example, as an annular seal that rests against an underside of the upper side wall 29 of the housing 2. A second section of the first chamber 4 is formed by a channel 11 of a carrier plate 10. The channel 11 extends from a top side to a bottom side through the carrier plate 10. On the underside, the channel 11 is sealed by a sensor 12 and / or an actuator 13.

[0029] The sensor 12 and / or the actuator 13 are attached to the underside 20 of the carrier plate 10 via an annular sealing surface 19. Furthermore, the sensor and / or the actuator 12, 13 are electrically connected to the carrier plate 10 via electrical contacts 21. The carrier plate 10 is designed, for example, as a printed circuit board and has electrical lines and / or electrical and / or electronic circuits. Thus, the actuator and / or the sensor, the carrier plate 10, and the seal 8 seal the first chamber 4 from the second chamber 5. The second chamber 5 is formed in the interior 3 of the housing 2 and surrounds the first chamber 4.

[0030] In addition, a second membrane 9 is formed between the opening 6 and the channel 11 of the carrier plate 10, which second membrane covers the entire cross-section of the first chamber 4. The first chamber 4 can have a cylindrical shape. The chamber 4 is thus divided into an upper partial chamber 22 and a lower partial chamber 23. The upper partial chamber 22 borders the opening 6. The lower partial chamber 23 borders the sensor / actuator 12, 13. The second membrane 9 is arranged between a bottom side of the seal 8 and a top side 24 of the carrier plate 10. For example, the second membrane 9 can be glued to the seal 8 and / or to the carrier plate 10. The second membrane 9 projects laterally into the second chamber 5 with an edge region 31, i.e. a surface of the second membrane 9 borders the second chamber 5 or is connected to the second chamber 5.The second membrane 9 has a predetermined air permeability, which allows for a specified pressure equalization between the first chamber 4 and the second chamber 5. The air permeability is designed such that the pressure equalization is slower than a predetermined value. As a result, pressure fluctuations exchanged via the opening 6 between the first chamber 4 and the surroundings of the housing 2 are not affected by the air permeability of the second membrane 7.

[0031] Thus, the air permeability between the first space 4 and the second space 5 is determined by the type of material of the second membrane 9 and / or by the thickness and / or the cross-sectional area available for the air exchange between the first space 4 and the second space 5.

[0032] The second chamber 5 is preferably also connected to the environment in an air-permeable manner via a second opening 16 in the housing 2 and a pressure equalization element 17. The pressure equalization element 17 can, for example, be formed from an air-permeable membrane that covers the second opening 16. The pressure equalization element 17 ensures that the second chamber 5 has essentially the same pressure as the environment outside the housing 2. Furthermore, the pressure equalization element 17 prevents dirt, dust, or other particles from entering the second chamber 5.

[0033] The interior space 3 of the housing 2 has, for example, a cuboid shape. The first space 4 has, for example, a substantially cylindrical shape.

[0034] The pressure equalization element 17 can be designed as an air-permeable film. The first membrane 7 can be designed as a non-porous membrane. The second membrane 9 represents an air-permeable membrane that enables pressure equalization between the first and second chambers. The first membrane 7 is designed to absorb pressure fluctuations on the outside of the housing and to move accordingly, passing the pressure fluctuations on to the first chamber 4. The second membrane 9 can enable an air flow into or out of the first chamber 4 that is, for example, less than 500 ml / minute at 6.9 kilopascals. Depending on the selected embodiment, the second membrane 9 can be designed to enable an air flow of 250 ml / minute at 6.9 kilopascals or less, such as 100 ml / minute at 6.9 kilopascals.

[0035] The sensor and / or actuator can, for example, comprise a MEMS element and be designed as a microphone, loudspeaker, or acoustic transmitter. The second membrane can, for example, be formed from a polymeric material, a metallic material, a ceramic material, a composite material, a textile material, or an adhesive material. Furthermore, the second membrane can be designed as an ePTFE membrane, a woven textile layer, or a woven textile composite layer. The membrane for the pressure compensation element can, for example, also be designed as an air-permeable membrane, which, however, allows a greater air flow over time than the second membrane. The first membrane 7 can, for example, be designed as a non-porous polymeric composite layer. Depending on the selected embodiment, the first membrane can comprise materials such as polymeric films (TPU, PET, FEP, and the like) or polymeric composites.The first membrane can, for example, have a thickness of less than 500 pm. The second membrane can, for example, be made of materials such as polyamide, polyester, or polyolefins such as polyethylene and polypropylene.

[0036] Figure 2 shows a schematic enlarged view of a partial section of the device 1 of Figure 1, wherein the arrangement of the second membrane 9 between the carrier plate 10 and the seal 8 is shown enlarged. In this embodiment, the second membrane 9 is fastened with an underside via a first adhesive layer 14 to the upper side 24 of the carrier plate 10. At the same time, the second membrane 9 rests with an upper side against an underside of the seal 8. Arranged laterally next to the seal 8 is an annular edge region 31 of the surface of the second membrane 7, which directly borders the second space 5. In this way, the second space 5 is connected to the first space 4 in an air-permeable manner by means of the second membrane 9. The air permeability of the second membrane 9 is designed such that long-term, slow pressure changes between the first space 4 and the second space 5 are essentially compensated.

[0037] Figure 3 shows a partial cross-section through a further embodiment of the device 1, wherein in this embodiment the second membrane 9 is connected to the carrier plate 10 via the first adhesive layer 14 and to the seal 8 via a second adhesive layer 15. In this embodiment too, a defined pressure equalization and thus air exchange between the first space 4 and the second space 5 is made possible. By forming the first and / or second adhesive layer 14, 15, an air channel 30 and / or cross-section of the second membrane that is effective for air exchange can be defined. In the example shown, an annular peripheral edge region 31 borders directly on the second space 5. A height of the edge region 31 is defined by the thickness of the second membrane 9.The effective air channel 30, which is available for air exchange between the first space 4 and the second space 5, is defined by the edge region 31, a cross-section of the second membrane 9 available for air exchange, the surface of the second membrane 9 that borders the first space 4, and a length of the air channel 30 within the second membrane 9. Thus, the first and second adhesive layers 14, 15 also represent a sealing layer for the surfaces of the second membrane 9. For example, instead of the first and second adhesive layers 14, 15, sealing layers can also be arranged that seal the surfaces of the second membrane and define an effective air channel 30 in the second membrane 9 for air exchange between the first and second spaces 4, 5.

[0038] Figure 4 shows a schematic representation of a cross-section with a plan view of the arrangement of Figure 3. An upper side of the second membrane 9 is covered with the second adhesive layer 15, which can also be designed solely as a sealing layer. The more of the surface of the second membrane 9 is covered by the adhesive layer, the lower the air exchange between the first and second spaces 4, 5. Thus, the size of the surface of the second adhesive layer 15 can be selected such that, for a given surface area of ​​the second membrane 9, a desired air exchange between the first and second spaces 4, 5 is achieved. The sealing layer can, for example, comprise plastic or be formed from plastic. The surface of the second membrane 9 that is not covered with the second adhesive layer 15 or not with the sealing layer forms the edge region 31, which borders the second space.

[0039] Figure 5 shows a further embodiment of a device 1, which is designed essentially according to the device 1 of Figure 1.

[0040] The housing 2 defines a cuboid-shaped interior space 3 with six side walls. A first space 4 and a second space 5 are arranged in the interior space 3. The housing 2 has an opening 6 on an upper side wall 29, which leads from an outside of the housing 2 to the interior space 3. The opening 6 is closed with a first membrane 7, which in the illustrated embodiment is arranged on the upper side of the upper side wall 29 of the housing 2. The upper side wall 29 can be designed as a cover. The first membrane 7 can be attached, for example, to the upper side of the side wall of the housing 2 via a third adhesive layer 18. The third adhesive layer 18 can be formed in a ring around the opening 6.

[0041] The first membrane 7 is essentially airtight and flexible in such a way that pressure fluctuations, such as acoustic signals, are transmitted from the outside of the housing via the first membrane 7 to the opening 6 and thus to the first chamber 4. In the same way, pressure fluctuations from the first chamber 4 are emitted to the environment via the opening 6 and the first membrane 7. In the illustrated embodiment, the first chamber 4 directly borders the opening 6.

[0042] In the illustrated embodiment, the first chamber 4 is delimited in a first section by a component, for example, a seal 8. The seal 8 is designed, for example, as an annular seal that rests against an underside of the upper side wall 29 of the housing 2. A second section of the first chamber 4 is formed by a channel 11 of a carrier plate 10. The channel 11 extends from a top side to a bottom side through the carrier plate 10. On the underside, the channel 11 is sealed by a sensor 12 and / or an actuator 13.

[0043] The sensor 12 and / or the actuator 13 are attached to the underside 20 of the carrier plate 10 via an annular sealing surface 19. Furthermore, the sensor and / or the actuator 12, 13 are electrically connected to the carrier plate 10 via electrical contacts 21. The carrier plate 10 is designed, for example, as a printed circuit board and has electrical lines and / or electrical and / or electronic circuits. Thus, the actuator and / or the sensor, the carrier plate 10, and the seal 8 seal the first chamber 4 from the second chamber 5. The second chamber 5 is formed in the interior 3 of the housing 2 and surrounds the first chamber 4.

[0044] The second chamber 5 is preferably also connected to the environment in an air-permeable manner via a second opening 16 in the housing 2 and a pressure equalization element 17. The pressure equalization element 17 can, for example, be formed from an air-permeable membrane that covers the second opening 16. The pressure equalization element 17 ensures that the second chamber 5 has essentially the same pressure as the environment outside the housing 2. In addition, the pressure equalization element 17 prevents dirt, dust, or other particles from entering the second chamber 5. The interior space 3 of the housing 2 has, for example, a cuboid shape. The first chamber 4 has, for example, a substantially cylindrical shape.

[0045] The first chamber 4 is connected to the second chamber 5 via a connecting channel 25, which is incorporated in the housing 2. In this embodiment, the connecting channel 25 is covered with the second membrane 9. Thus, in this embodiment, air exchange between the first chamber 4 and the second chamber 5 is only possible under defined conditions.

[0046] The connecting channel 25 can be formed in various regions of the housing 2. In addition, the connecting channel 25 can open into various sections of the first chamber 4. In one embodiment, the connecting channel is arranged in the upper side wall 29 and opens into a first channel opening 26 on an outer side of the housing. The first channel opening 26 is arranged below the first membrane 7. Preferably, the first channel opening 26 is formed in a recess 27. The recess 27 is formed in the outer side of the housing 2 and has a predetermined depth. In addition, the recess 27 extends laterally into the first chamber 4. Preferably, the depth of the recess 27 is selected such that the second membrane 9 can be arranged in the recess 27 without impairing the first membrane 7 in the event of a deflection or without coming into contact with the first membrane 7.In this way, the first channel opening 26 is far away from the sensor and / or actuator 12, 13. Thus, pressure changes or air exchange via the second membrane 9 have little or no influence on the sensor's reception sensitivity and / or the actuator's effectiveness.

[0047] In this example, the second edge region 31 is formed by the surface of the second membrane 9 that borders the connecting channel 25. The second membrane 9 has a predetermined air permeability that enables a specified pressure equalization between the first space 4 and the second space 5. The air permeability is designed such that the pressure equalization is slower than a predetermined value. As a result, pressure fluctuations exchanged via the opening 6 between the first space 4 and the surroundings of the housing 2 are not affected by the air permeability of the second membrane 7.

[0048] Thus, the air permeability between the first space 4 and the second space 5 is determined by the type of material of the second membrane 9 and / or by the thickness and / or the cross-sectional area available for the air exchange between the first space 4 and the second space 5.

[0049] Depending on the selected embodiment, the first membrane 7 can be covered with a protective cap 28 to protect it from mechanical damage or contamination in all embodiments of the device. The protective cap 28 has openings for air exchange or pressure changes.

[0050] Figure 6 shows a schematic plan view of the arrangement of Figure 5 in a section between the first membrane 7 and the second membrane 9. It can be seen that the recess 27 extends laterally into the first space 4. In addition, the second membrane 9 is arranged in the recess 27 and completely covers the first channel opening 26. As already explained, the first channel opening 26 could also open laterally into the first space 4, and the recess 27 could be omitted.

[0051] In all embodiments, the first chamber 4 is sealed from the second chamber 5 except for the second membrane 9. Thus, a pressure wave in the first chamber 4 is transmitted through the second chamber 5 with as little influence as possible.

Claims

Claims 1. An acoustic device (1) comprising a housing (2), wherein the housing (2) has an opening (6) leading into an interior space (3) of the housing (2), wherein the opening (6) is closed by a first membrane (7), wherein the interior space (3) of the housing (2) has a first and a second space (4, 5), wherein the first space (4) is connected to the opening (6) of the housing (2), wherein a sensor (12) for receiving a pressure signal and / or an actuator (13) for generating a pressure signal is arranged in the first space (4), wherein the first membrane (7) is designed to transmit pressure fluctuations between the first space (4) and an environment outside the housing (2), wherein a second membrane (9) is provided between the first space (4) and the second space (5), wherein the second membrane (9) has a predetermined air permeability and enables pressure equalization between the first and second spaces (4, 5),where the pressure equalization is slower than a specified value.

2. Device according to claim 1, wherein the second space (5) is connected to an environment outside the housing (2) via a pressure equalization element (17).

3. Device according to one of the preceding claims, wherein the second membrane (9) is arranged between the first membrane (7) and the sensor (12) and / or the actuator (13) and covers an entire cross-section of the first space (4), and wherein the second membrane (9) is guided with an edge region (31) into the second space (5).

4. Device according to one of the preceding claims, wherein at least a section of the first space (4) is formed by a continuous channel (11) of a support plate (10), wherein the sensor (12) and / or actuator (13) adjoins the channel (11) and seals the channel (11) from the second space (5), and wherein the second membrane (9) is arranged between the opening (6) and the support plate (10) and projects laterally into the second space (6) with an edge region (31).

5. Device according to one of the preceding claims, wherein the second membrane (9) is connected to an underside of a seal (8) with an adhesive layer (15) and / or to an upper side of a carrier plate (11) with a further adhesive layer (14).

6. Device according to one of the preceding claims, wherein a connecting channel (25) is introduced into the housing (2), wherein the connecting channel (25) is guided from the second space (5) into the first space (4), and wherein the connecting channel (4) is closed with the second membrane (9).

7. Device according to claim 6, wherein the first membrane (7) is fastened on an outer side of the housing (2), wherein the connecting channel (25) is led from an inner side of the housing (2) to a first channel opening (26), wherein the first channel opening (26) opens into the first space (4), wherein the first channel opening (26) is covered with the second membrane (9).

8. Device according to claim 7, wherein the first channel opening (26) is arranged on an outer side of the housing (2) and below the first membrane (7), wherein the second membrane (9) covers the first channel opening (26).

9. Device according to claim 8, wherein the first channel opening (26) opens into a recess (27) in the outside of the housing (2), wherein the recess (27) opens laterally into the opening (6), wherein the second membrane (9) is arranged in the recess (27), and wherein the first membrane (7) covers the opening (6) and the recess (27).

10. Device according to one of the preceding claims, wherein the actuator (13) is designed to generate sound signals.

11. Device according to one of the preceding claims, wherein the sensor (12) is provided for detecting a pressure signal and / or a sound signal.

12. Device according to one of the preceding claims, wherein a protective cover (28) is arranged on the outside of the housing over the first membrane (7).

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