WO2023247046A1

WO2023247046A1 - Microelectromechanical audio module and apparatus comprising such audio module

Info

Publication number: WO2023247046A1
Application number: PCT/EP2022/067208
Authority: WO
Inventors: Oliver MERILAID; Jouni Tapio MÄKI; Antero Tossavainen
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2022-06-23
Filing date: 2022-06-23
Publication date: 2023-12-28

Abstract

A microelectromechanical audio module (1) comprising an enclosure (2) comprising an exterior shell (3) and interior support walls (4) extending within said exterior shell (3). At least one first diaphragm (5) and at least one second diaphragm (6) are arranged within said enclosure, said first diaphragm (5) being fixed to a first set of interior support walls (4a) and said second diaphragm (6) being fixed to a second set of interior support walls (4b). Each first diaphragm (5) is part of a first transducer unit (7) configured to generate audio output signals, and each second diaphragm (6) is part of a second transducer unit (8) configured to register audio input signals. The module (1) may comprise at least one integrated circuit, such as an amplifying circuit connected to said first transducer unit (7). The module (1) may also comprise several second transducer units (8) of identical or different types.

Description

MICROELECTROMECHANICAL AUDIO MODULE AND APPARATUS COMPRISING SUCH AUDIO MODULE

TECHNICAL FIELD

The disclosure relates to a microelectromechanical audio module and an electronic apparatus comprising a microelectromechanical audio module.

BACKGROUND

Device technology evolves toward smaller size devices and, more recently, demand has been growing for wearables and hearables. This has driven the development of transducer components with smaller and smaller dimensions. For example, the MEMS (Micro ElectroMechanical Systems) microphone was developed already in 1983 by Hohm and Sessler, but it was not commonly used until the mobile phone market started to expand. The most recent developments in the microspeaker field have led to the introduction of MEMS speakers that have drastically reduced size.

One type of device using MEMS speakers or microphones are True Wireless Stereo (TWS) headsets, TWS headsets currently being one of the most important and competitive audio device groups based on the market share. TWS headsets have very limited in size and battery size is critical. Additionally, recent TWS trends include integrating various types of additional sensors for health sensing, head-tracking etc., as well as using multiple microphones for beamforming or active noise cancellation, or bone conduction microphones. Some devices even come equipped with multi-way speakers such as Dynamic Driver (DD) or Balanced Armature (BA) speakers. All of these components require space within the headset, and space is the most desired feature of such devices.

In order to produce sufficiently low-distortion low-frequency sound pressure levels for ANC, DD transducers are typically used. DD transducers are large in size and take up most of the space of the TWS headset together with the battery. However, using only DD transducers leads to decreased high-frequency performance due to the location limitations - the higher frequencies suffer when the speaker is installed inside a tube. Hence, in order to achieve also good high- frequency performance, a BA transducer is added, which takes up even more space in the TWS headset. Furthermore, in modern hybrid ANC implementations an in-ear ANC error microphone is required, which in turn requires space. The use of many different acoustic components not only affects the space available within the TWS headset but also results in a complicated system with high manufacturing costs.

Hence, there is a need for an improved microelectromechanical audio module.

SUMMARY

It is an object to provide an improved microelectromechanical audio module. The foregoing and other objects are achieved by the features of the independent claims. Further implementation forms are apparent from the dependent claims, the description, and the figures.

According to a first aspect, there is provided a microelectromechanical audio module comprising an enclosure comprising an exterior shell and interior support walls extending within the exterior shell; and at least one first diaphragm and at least one second diaphragm arranged within the enclosure, the first diaphragm being fixed to a first set of interior support walls and the second diaphragm being fixed to a second set of interior support walls. Each first diaphragm is part of a first transducer unit configured to generate audio output signals, and each second diaphragm is part of a second transducer unit configured to register audio input signals.

Such a solution provides a less complex solution having a small footprint and which is highly suitable in small apparatuses such as in-ear earphones. The smaller the component, the more space is left for other components such as a battery, and the easier it is to place the component in the best position to achieve good high-frequency performance. The solution also has a reduced number of components, reducing the individual manufacturing tolerances (e.g., sealing, location, and mechanical tolerances) that need to be considered, simplifying manufacture, and simplifying assembly into electronic devices. A reduced number of components and simplified manufacture also leads to lower material and manufacturing costs.

In a possible implementation form of the first aspect, the first transducer unit has speaker functionality and the second transducer unit has microphone functionality. By providing these two functionalities, the objectives of the invention are achieved by means of an as small, simple, and reliable solution as possible. In a further possible implementation form of the first aspect, the second transducer unit is one of a dynamic microphone, a piezoelectric microphone, a condenser microphone, a capacitive microphone, a voice pick-up bone sensor, or an accelerometer, providing g the unit with maximum flexibility.

In a further possible implementation form of the first aspect, at least one of the first transducer unit and/or the second transducer unit is configured for beamforming or active noise cancellation, allowing the units to be used not only for voice pick-up but also for other purposes.

In a further possible implementation form of the first aspect, the exterior shell and the interior support walls is a one-piece element, simplifying manufacture and reducing the number of different tolerances that need to be taken into account. Furthermore, acoustic sealing is improved.

In a further possible implementation form of the first aspect, the enclosure comprises at least one sound port arranged adjacent at least one of the first transducer unit and the second transducer unit, allowing best quality possible sound waves to leave the module.

In a further possible implementation form of the first aspect, the audio module further comprises at least one integrated circuit, further simplifying manufacture as well as assembly of any apparatuses comprising the module. This also allows the number of electrical contacts to be reduced as well as ultra-short wiring, improving signal quality.

In a further possible implementation form of the first aspect, the first diaphragm is arranged in a first plane and the second diaphragm is arranged in a second plane parallel to the first plane, such that an actuation axis of the first transducer unit extends coaxially with an actuation axis of the second transducer unit. This allows for a very small module which also may be easily adapted and scaled to suit different conditions.

In a further possible implementation form of the first aspect, the enclosure comprises an interior partition wall separating an interior of the exterior shell into a first air volume and a second air volume, the first diaphragm and the first set of interior support walls being arranged within the first air volume, and the second diaphragm and the second set of interior support walls being arranged within the second air volume. This allows the speaker and microphone functionalities to be completely separated.

According to a second aspect, there is provided an electronic apparatus comprising the microelectromechanical audio module according to the above. This allows an apparatus that has a small footprint yet still has high audio performance. The size reduction can be utilized either to improve comfort or to allow more additional components within the apparatus. Furthermore, manufacturing as well as assembly is simplified.

In a possible implementation form of the second aspect, the electronic apparatus further comprises at least one battery and/or audio playback unit, allowing a complete and self- sustaining apparatus.

In a further possible implementation form of the second aspect, the apparatus is an in-ear headset, the in-ear headset comprising at least one housing adapted for being at least arranged partially within an ear canal of a user, the housing comprising an opening allowing sound waves to propagate from the housing into the ear canal; the microelectromechanical audio module being arranged within the housing such that at least the first transducer unit of the microelectromechanical audio module is arranged adjacent the opening in the housing. This allows the audio module to be placed as close to the ear canal as possible.

These and other aspects will be apparent from the embodiments described below.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present disclosure, the aspects, embodiments, and implementations will be explained in more detail with reference to the example embodiments shown in the drawings, in which:

Fig. 1 shows a perspective cross-sectional view of a microelectromechanical audio module in accordance with an example of the embodiments of the disclosure;

Fig. 2 shows a perspective cross-sectional view of a microelectromechanical audio module in accordance with an example of the embodiments of the disclosure;

Fig. 3 shows a cross-sectional side view of a microelectromechanical audio module in accordance with an example of the embodiments of the disclosure; Fig. 4 shows a cross-sectional side view of a microelectromechanical audio module in accordance with an example of the embodiments of the disclosure.

DETAILED DESCRIPTION

The present invention relates to a microelectromechanical audio module 1 comprising an enclosure 2 comprising an exterior shell 3 and interior support walls 4 extending within the exterior shell 3 and at least one first diaphragm 5 and at least one second diaphragm 6 arranged within the enclosure, the first diaphragm 5 being fixed to a first set of interior support walls 4a and the second diaphragm 6 being fixed to a second set of interior support walls 4b, each first diaphragm 5 being part of a first transducer unit 7 configured to generate audio output signals, and each second diaphragm 6 being part of a second transducer unit 8 configured to register audio input signals.

Figs. 1 to 4 show different examples of microelectromechanical audio modules 1. The microelectromechanical audio module 1 comprises an enclosure 2 comprising an exterior shell 3 and interior support walls 4 extending within the exterior shell 3. The enclosure 2, i.e. the exterior shell 3 and the interior support walls 4, may be a one-piece element, i.e. no assembly being needed but all parts of the enclosure 2 being made of one piece. The enclosure 2 may, e.g., be manufactured by means of additive manufacturing.

At least one first diaphragm 5 and at least one second diaphragm 6 are arranged within the enclosure 2. The first diaphragm 5 is fixed to a first set of interior support walls 4a and the second diaphragm 6 is fixed to a second set of interior support walls 4b.

The first diaphragm 5 and the second diaphragm 6 may be arranged coplanarly in a common first plane Pl as illustrated in Fig. 1, such that an actuation axis Al of the first transducer unit 7 extends in parallel with an actuation axis A2 of the second transducer unit 8. In this embodiment, the first set of interior support walls 4a and the second set of interior support walls 4b extend from the same part of the exterior shell 3, e.g., the lower section as shown in Fig. 1.

The first diaphragm 5 may also be arranged in the first plane Pl and the second diaphragm 6 may be arranged in a second plane P2 parallel to the first plane Pl, such that the actuation axis Al of the first transducer unit 7 extends coaxially with the actuation axis A2 of the second transducer unit 8, as illustrated in Figs. 2 to 4. The first set of interior support walls 4a and the second set of interior support walls 4b may extend from different parts of the exterior shell 3, e.g., the first set of interior support walls 4a may extend from the upper section while the second set of interior support walls 4b extend from the lower section as shown in Fig. 2.

One or both of the first set of interior support walls 4a and the second set of interior support walls 4b may be arranged such that is “floats” within the enclosure 2. For example, Fig. 3 shows an embodiment wherein the second set of interior support walls 4b extend from the lower section while the first set of interior support walls 4a may protrude from, or be fixed to, the exterior shell 3 in some other way allowing it to be arranged in substantially the center of the enclosure 2.

The enclosure 2 may also comprise an interior partition wall 10 separating the interior of the exterior shell 3 into a first air volume 11 and a second air volume 12, as shown in Fig. 4. The first diaphragm 5 and the first set of interior support walls 4a are arranged within the first air volume 11, and the second diaphragm 6 and the second set of interior support walls 4b are arranged within the second air volume 12.

By “actuation axis” is meant the main axes along which the first diaphragm 5 and the second diaphragm 6 move when vibrating.

As mentioned above, the first diaphragm 5 and the second diaphragm 6 may be arranged side- by-side, facing the same open volume within the enclosure 2 as shown in Fig. 1. The first diaphragm 5 and the second diaphragm 6 may be arranged adjacent each other, separated by an air gap only as shown in Fig. 2. The first diaphragm 5 and the second diaphragm 6 may be arranged in parallel but separated by, e.g., the first set of interior support walls 4a or one or several partition walls 10, as shown in Figs. 3 and 4. The first diaphragm 5 and the second diaphragm 6 may also be arranged at any suitable angle to each other.

The first diaphragm 5 is part of a first transducer unit 7 configured to generate audio output signals such as sound waves. The first transducer unit 7 may have speaker functionality. The microelectromechanical audio module 1 may comprise several first transducer units 7, i.e., several speakers.

The second diaphragm 6 is part of a second transducer unit 8 configured to register audio input signals in the form of, e.g., sound waves, structural vibrations, and/or changes in acceleration. The second transducer unit 8 may have microphone functionality. The second transducer unit 8 may be one of a dynamic microphone, a piezoelectric microphone, a condenser microphone, a capacitive microphone, a voice pick-up bone sensor, or an accelerometer. The microelectromechanical audio module 1 may comprise several second transducer units 8 and the second transducer units 8 may be identical or different, e.g., one dynamic microphone as well as one accelerometer.

At least one of the first transducer unit 7 and the second transducer unit 8 may be configured for beamforming or active noise cancellation.

The enclosure 2 may comprise at least one sound port 9 arranged adjacent at least one of the first transducer unit 7 and the second transducer unit 8. By “adjacent” is meant as physically close as possible, since the audio quality will be better the closer the different parts are. The first transducer unit 7 and the second transducer unit 8 are acoustically connected to at least one sound port 9, i.e., the same sound port 9 as shown in Figs. 1 to 3 or to different sound ports 9 as shown in Fig. 4. The sound port(s) may be arranged in parallel with the first diaphragm 5 and the second diaphragm 6, along the actuation axes Al, A2, as shown in Figs. 1, 2, and 4, or side-by-side with the diaphragms 5, 6 and the actuation axes Al, A2 as shown in Fig. 2. A side- by-side arrangement allows ultra-short acoustic integration between transducer unit and sound port.

The audio module 1 may also comprise at least one integrated circuit. The integrated circuit may be fixed to the exterior shell 2 and/or the interior support walls 4 of the enclosure 2, e.g. via printed circuit boards onto which the integrated circuits are soldered. The integrated circuit may be an amplifier circuit, a digital to analog converter circuit, an analog to digital converter circuit, or a digital signal processing circuit. In one embodiment, the first transducer unit 7, having speaker functionality, comprises also an amplifier circuit. The present invention also relates to an electronic apparatus comprising the microelectromechanical audio module 1. The electronic apparatus may be any kind of apparatus such as a tv or headphones.

The electronic apparatus may comprise at least one battery and/or audio playback unit, making the apparatus an at least partially self-sufficient device.

The electronic apparatus may be an interaural apparatus, i.e., an in-ear headset. The in-ear headset comprises at least one housing adapted for being at least arranged partially within an ear canal of a user, and the housing comprises an opening allowing sound waves to propagate from the housing into the ear canal. The microelectromechanical audio module 1 is arranged within the housing such that at least the first transducer unit 7 of the microelectromechanical audio module 1 is arranged adjacent the opening in the housing. The housing may be configured to at least partially block the ear canal of the user. One part of the housing may be configured to be arranged in the concha of the user’s ear.

The various aspects and implementations have been described in conjunction with various embodiments herein. However, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed subject-matter, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.

The reference signs used in the claims shall not be construed as limiting the scope. Unless otherwise indicated, the drawings are intended to be read (e.g., cross-hatching, arrangement of parts, proportion, degree, etc.) together with the specification, and are to be considered a portion of the entire written description of this disclosure. As used in the description, the terms “horizontal”, “vertical”, “left”, “right”, “up” and “down”, as well as adjectival and adverbial derivatives thereof (e.g., “horizontally”, “rightwardly”, “upwardly”, etc.), simply refer to the orientation of the illustrated structure as the particular drawing figure faces the reader. Similarly, the terms “inwardly” and “outwardly” generally refer to the orientation of a surface relative to its axis of elongation, or axis of rotation, as appropriate.

Claims

1. A microelectromechanical audio module (1) comprising

-an enclosure (2) comprising an exterior shell (3) and interior support walls (4) extending within said exterior shell (3); and

-at least one first diaphragm (5) and at least one second diaphragm (6) arranged within said enclosure, said first diaphragm (5) being fixed to a first set of interior support walls (4a) and said second diaphragm (6) being fixed to a second set of interior support walls (4b); each first diaphragm (5) being part of a first transducer unit (7) configured to generate audio output signals, each second diaphragm (6) being part of a second transducer unit (8) configured to register audio input signals.

2. The audio module (1) according to claim 1, wherein said first transducer unit (7) has speaker functionality and said second transducer unit (8) has microphone functionality.

3. The audio module (1) according to claim 1 or 2, wherein said second transducer unit (8) is one of a dynamic microphone, a piezoelectric microphone, a condenser microphone, a capacitive microphone, a voice pick-up bone sensor, or an accelerometer.

4. The audio module (1) according to any one of the previous claims, wherein at least one of said first transducer unit (7) and/or said second transducer unit (8) is configured for beamforming or active noise cancellation.

5. The audio module (1) according to any one of the previous claims, wherein said exterior shell (3) and said interior support walls (4) is a one-piece element.

6. The audio module (1) according to any one of the previous claims, wherein said enclosure (2) comprises at least one sound port (9) arranged adjacent at least one of said first transducer unit (7) and said second transducer unit (8).

7. The audio module (1) according to any one of the previous claims, further comprising at least one integrated circuit.

8. The audio module (1) according to any one of the previous claims, wherein said first diaphragm (5) is arranged in a first plane (Pl) and said second diaphragm (6) is arranged in a second plane (P2) parallel to said first plane (Pl), such that an actuation axis (Al) of said first transducer unit (7) extends coaxially with an actuation axis (A2) of said second transducer unit (8).

9. The audio module (1) according to any one of the previous claims, wherein said enclosure (2) comprises an interior partition wall (10) separating an interior of said exterior shell (3) into a first air volume (11) and a second air volume (12), said first diaphragm (5) and said first set of interior support walls (4a) being arranged within said first air volume (11), and said second diaphragm (6) and said second set of interior support walls (4b) being arranged within said second air volume (12).

10. An electronic apparatus comprising the microelectromechanical audio module (1) according to any one of claims 1 to 9.

11. The electronic apparatus according to claim 10, further comprising at least one battery and/or audio playback unit.

12. The electronic apparatus according to claim 10 or 11, wherein said apparatus is an in-ear headset, said in-ear headset comprising at least one housing adapted for being at least arranged partially within an ear canal of a user, said housing comprising an opening allowing sound waves to propagate from said housing into said ear canal; said microelectromechanical audio module (1) being arranged within said housing such that at least the first transducer unit (7) of said microelectromechanical audio module (1) is arranged adjacent said opening in said housing.