Acoustic bending transducer system and acoustic device

Abstract

The invention relates to an acoustic bending transducer system (1, 2) having a plurality of bending transducers (3, 4, 5) which are arranged such that the deformable elements (31, 32, 41; 32, 34, 42; 31, 32, 3'1, 3'2) of the bending transducers (3, 4, 5) oscillate coplanarly in a common plane layer (10), wherein the bending transducers (3, 4, 5) comprise different resonance frequencies and different expansions of the deformable elements (31, 32, 41; 32, 34, 42; 31, 32, 3'1, 3'2) along a common longitudinal axis which is transverse to the oscillation direction of the deformable elements (31, 32, 41; 32, 34, 42; 31, 32, 3'1, 3'2). Furthermore, the invention relates to an acoustic device having such an acoustic bending transducer system (1, 2).

Description

Technical Field

[0001] An embodiment according to the invention relates to a micromechanical sound transducer. Background Art

[0002] The technical field of the invention can be attributed to the following three documents describing micromechanical devices:

[0003] ·WO 2012 / 095185 A1 / Title: MIKROMECHANISCHES BAUELEMENT

[0004] ·WO 2016 / 202790 A2 / Title: MEMS TRANSDUCER FOR INTERACTING WITH AVOLUME FLOW OF A FLUID AND METHOD FOR PRODUCING SAME

[0005] DE 10 2015 206 774 A1

[0006] Basically, these documents disclose the structure of the bending converter and specific options and mechanisms of its interaction with the environment. In particular, the above-mentioned documents relate to a novel MEMS (Micro Electro Mechanical System) actuator principle based on the fact that a silicon beam moves laterally in a plane (e.g. a substrate plane defined by a silicon disk or wafer). Here, the silicon beam connected to the substrate in a cavity interacts with a volume flow. The novel MEMS described therein is defined as NED (Nano Electrostatic Drive).

[0007] Due to their proportions, these NEDs are particularly suitable for the miniaturization of everyday devices with increased integration requirements (reducing components while maintaining a full range of functions). For example, ultra-mobile end devices such as smart watches or ear-worn devices are subject to very strict installation space design restrictions. With the above-mentioned NEDs, sound transducers that can meet these increased requirements can be realized, where the sound volume and sound quality can be significantly improved compared to conventional sound transducers. Here, the integration requirements involve the overall adaptability to the existing installation space and the system design with several components.

[0008] Document DE 10 2017 114 008 A1 discloses a hearing aid or earphone, which is designed so that the outer dimensions of the housing correspond to the inner dimensions of the ear canal. A MEMS-based sound transducer is arranged in the housing so that a front volume is formed in the direction of the eardrum and a rear volume is formed in the direction of the earpiece, which are separated from each other by a MEMS-based sound transducer. With regard to its geometric dimensions, the sound transducer is configured so that it does not limit the geometric dimensions of the resonance volume, however, it is difficult to keep the frequency response constant over a large frequency range. In addition, the sound transducer consists of bending transducers, which are elastically suspended on one side extending across the cavity and whose edge areas are separated by a gap at the front side. Due to the curvature of the sound transducer, the gap increases. In addition, a sound insulation device formed by side walls is disclosed, i.e., the so-called sound insulation walls of the cavity. These sound insulation walls are arranged so that they at least partially prevent lateral sound from passing along the gap. A disadvantage of the present disclosure is that the sound transducer is piezoelectric and is therefore pre-bent, so that the disclosed measures are used to minimize the inaccuracies that occur due to the pre-bending.

[0009] Document DE 10 2017 108 594 A1 discloses a loudspeaker unit for a portable device for generating sound waves in the audible range, which is characterized by a low structural size and high performance. In addition to an electrodynamic loudspeaker, the loudspeaker unit comprises a MEMS-based high-frequency loudspeaker, wherein the frequency ranges of the two loudspeakers overlap. The electrodynamic loudspeaker is thus formed in a compact manner and is optimized for low frequencies. However, high space requirements and high power consumption remain disadvantages due to the necessity to operate two different system technologies.

[0010] Furthermore, document DE 196 124 81 A1 discloses an arrangement of a sound transducer for a hearing aid that is tilted relative to the longitudinal axis. The sound-generating membrane is a conductive membrane that is arranged between two surface electrodes and that generates sound in the audible wavelength spectrum through its oscillation. The membrane is not arranged parallel to the eardrum, thereby minimizing undesired resonances in the ear canal. However, in this structure, no other functional elements can be integrated monolithically, so additional space is required outside the ear canal.

[0011] The known solution does not require a particularly dense packing of the acoustic transducers or the use of external assembly methods to supplement the individual functions (eg electrical connections).

[0012] In view of the above, there is a need for a concept that allows the packing density of devices to be increased compared to the prior art in order to effectively and efficiently achieve high sound pressure.

[0013] It is therefore an object of the present invention to provide an acoustic bending transducer system with increased efficiency and an acoustic device for improving sound conversion in a conduit such as the ear canal.

[0014] For example, by a compact arrangement of a plurality of bending transducers of a bending transducer system, a high reproduction quality is ensured in the environment around the bending transducer system, which is configured as a sound transducer, and allows integration of other system components under limited space conditions. Due to the combination of the transducers and the surrounding installation space, the frequency response reproduced by the sound transducer can be kept constant over a large frequency range, for example via an oblique orientation of the volume flow in a duct such as the ear canal. A variation can be, for example, less than 6 dB.

[0015] The present application describes further developments for optimizing the arrangement of bending transducers with respect to space requirements, sound pressure level and sound quality, which can be provided by a NED in a specific environment, for example in the ear canal of a human ear.

[0016] An acoustic bending transducer system is proposed with a plurality of bending transducers, which are configured so that the deformable elements of the bending transducers oscillate in the same plane in a common plane layer, wherein the bending transducers include different resonant frequencies and different expansions of the deformable elements along a common longitudinal axis, which is transverse to the oscillation direction of the deformable elements. The bending transducers can be, for example, electrostatic bending actuators (NED actuators), piezoelectric actuators or thermomechanical actuators. The plurality of bending transducers are configured to deflect in an oscillation plane. Here, the bending transducers are arranged side by side along a first axis in a common plane layer or oscillation plane and extend along a second axis transverse to the first axis. In order to make full use of the spatial conditions within the same common plane layer, the single or multiple bending transducers can also be arranged obliquely relative to the plurality of bending transducers oriented in parallel.

[0017] Another aspect of the present application relates to an acoustic device (e.g., a hearing aid) comprising: an acoustic bending transducer system having at least one bending transducer, the at least one bending transducer comprising at least one deformable element arranged in a cavity; and an opening through which a fluid volume flow interacting with the movement of the bending transducer in the cavity passes; and a housing adapted to be inserted into a pipe, wherein the bending transducer system is held in the housing so that the fluid volume flow can be oriented obliquely to the longitudinal axis of the pipe in a state in which the housing is inserted into the pipe. The acoustic device can be miniaturized and is therefore particularly suitable for incorporation into in-ear hearing aids (IdOs) and ear-worn devices as well as smart watches and other ultra-mobile terminal devices.

[0018] The advantages and functionalities of the features of the acoustic bending transducer system as described above and below apply correspondingly to an acoustic device provided with the acoustic bending transducer system.

[0019] According to an embodiment, a bending converter system comprises: one or several cavities, in which bending converters are arranged; and one or several openings in the cavity, through which a fluid volume flow interacting with the plurality of bending converters can pass. Here, the opening in the cavity can be a common opening of two or several cavities that are connected to each other via the fluid volume flow. Furthermore, the opening in the cavity of the bending converter system enables the individual bending converters or the bending converter system to be connected to the surrounding environment.

[0020] According to an embodiment, the bending converter is arranged in a space bounded by a first substrate and a second substrate parallel to a common oscillation plane and a wall between the substrates, the wall dividing the space into cavities arranged between adjacent bending converters in the common oscillation plane along a longitudinal direction or in a direction transverse to the longitudinal direction. In this way, the cavity is, for example, bounded by the first substrate, the second substrate and two opposing walls from adjacent bending converters. Since the plurality of bending converters are configured to deflect in the common oscillation plane of the layer via their deformable elements, the distance of the bending converters from the first substrate and the second substrate is a distance at which adjacent cavities can be fluidically coupled to each other. Through the fluid coupling of adjacent cavities, the plurality of bending converters can exert a common force on the fluid in the cavity, whereby a high sound level can be achieved using a micromechanical sound converter.

[0021] Depending on the embodiment, each bending transducer of the acoustic bending transducer system may comprise a deformable element which can be deformed electrostatically, piezoelectrically or thermomechanically. This results in a plurality of options for adapting the bending transducer system to desired requirements in a flexible manner.

[0022] Furthermore, the acoustic bending transducer system is particularly advantageous when at least a first subset of at least one first bending transducer each comprises a cantilevered deformable element and additionally or alternatively at least a second subset of at least one second bending transducer comprises a cantilevered deformable element clamped on both sides. On the one hand, the grouping of individual subsets of specific bending transducers allows for an appropriate use of the installation space and at the same time allows for a specific positioning of similar bending transducers to generate a desired frequency or sound pressure. Since the deformable element of each bending transducer can be cantilevered or clamped on both sides, bending transducers with deformable elements of different mechanical properties and dimensions can be realized, which are again responsible for generating different frequencies and sound pressures. Furthermore, the installation space present in the same layer of the bending transducer system can be used in a particularly advantageous manner.

[0023] Advantageously here, for a cantilever bending transducer, a larger oscillation amplitude is generated at a higher frequency, since the cantilever bending transducer is characterized by a favorable ratio of mass to length of the deformable element of the bending transducer.

[0024] In order to be able to reproduce different frequencies and / or generate different sound pressures, according to a particularly advantageous embodiment, at least a first subset of at least one first bending transducer comprises an average higher resonance frequency than at least a second subset of at least one second bending transducer, and vice versa. Due to the special requirements for the installation space and for the different frequencies and their sound pressures, the stiffness, mass, length and cross-sectional geometry of the deformable elements of the respective bending transducers can be adjusted.

[0025] In order to be able to reproduce different frequencies and / or generate different sound pressures in a very simple and dedicated manner, a first subset of at least one first bending transducer comprises an average shorter length than a second subset of at least one second bending transducer.

[0026] According to a particularly preferred embodiment, each bending converter delimits two opposing cavities, wherein each cavity is accessible via at least one opening for passing a fluid volume flow. It is thus possible to fluidically couple the individual cavities and thereby specifically control the properties of the volume flow transmitted by the individual bending converter, which may be particularly desirable with respect to the pressure or acoustic pressure of the volume flow that can be established.

[0027] In order to generate sound pressure in the spectrum accessible to human hearing by means of the acoustic bending transducer system, it is proposed to provide a deformable element in the bending transducer with a length of more than 100 μm. In order to allow a very compact construction of the miniaturized sound transducer, the length of the deformable element of each bending transducer should be less than 4000 μm. In order to save space, the bending transducer system is incorporated into a longitudinally extending sleeve, the outer dimension of the bending transducer system along the common longitudinal axis being at most transverse to the common plane layer and being greater than the outer dimension of the bending transducer system transverse to the common plane.

[0028] In a particularly preferred embodiment, the outer dimension of the bend transducer system along the common longitudinal axis is between 750 μm and 2000 μm. In an even more preferred embodiment, the outer dimension of the bend transducer system along the common longitudinal axis is between 800 μm and 1200 μm. A bend transducer system with the above outer dimensions can be incorporated into an in-ear hearing aid in a space-saving manner, wherein a sufficient listening quality for the user can be ensured.

[0029] In a particularly preferred embodiment, the outer surface of the curved transducer describes a longitudinal ellipse coplanar with the common plane layer along the common longitudinal axis, a longitudinal rectangle coplanar with the common plane layer along the common longitudinal axis, or a longitudinal polygon coplanar with the common plane layer along the common longitudinal axis. Such a longitudinal shape allows good utilization of the installation space in a longitudinally extending sleeve with a cylindrical or rectangular cross-section. In addition, by appropriately selecting the outer surface or outer contour of the curved transducer system, the inner cross-section of the longitudinally extending sleeve can be essentially completely filled, for example, the ear canal can be sealed.

[0030] According to an advantageous embodiment, the bending converters are divided into groups of one or several bending converters, wherein in a group of several bending converters, several bending converters are arranged behind each other along a common longitudinal axis. In this arrangement, the individual pressures of the volume flow affected by the corresponding deformable elements of the bending converters will be added. Therefore, by an advantageous staggering or grouping of the bending converters and their selective activation, not only the desired pressure or sound pressure of the volume flow distributed to the environment can be specifically controlled, but also different sound frequencies can be generated. For example, short bending converters can be arranged in the opening area, because they are characterized by a relatively high stiffness compared to long bending converters, whereby high resonance frequencies are possible. As long as such bending converters are arranged in the opening area connecting the cavity to the environment, resonances can be prevented, so that the sound quality or listening quality can be improved. Additionally or alternatively, according to another advantageous embodiment, the bending converters are divided into groups of one or several bending converters, wherein in a group of several bending converters, several bending converters are arranged side by side in a common plane transverse to the common longitudinal axis. Similar to the arrangement of several bending transducers behind each other along a common longitudinal axis, in a side-by-side arrangement transversely to the common longitudinal axis, the desired sound pressure and localization of the sound can also be controlled.

[0031] Advantageously, the fluid volume flow in the bend transducer system of the acoustic device flows in the plane of a common planar layer of the bend transducer system. Due to the arbitrary design and orientation of the cavities and deformable elements of the individual bend transducers of the bend transducer system, a specific course of the fluid volume flow in the bend transducer system can be provided and thus controlled. Thus, the volume flow can be specifically directed to a location where its influence on the environment is optimal.

[0032] In order to obtain a particularly favorable interaction with the environment of the acoustic device, the bending converter system is held in a housing so that the volume flow of the fluid of the acoustic device passes through the opening of the bending converter system at an angle of between 5° and 80°, between 10° and 40°, or between 15° and 30° with respect to the longitudinal axis of the pipe. By arranging the bending converter with respect to the longitudinal axis of the pipe, the deformable elements are positioned in an anti-parallel manner with respect to their orientation (for example, in the direction of the tympanic membrane of the human ear), so that resonances in the ear canal are minimized. In addition, a higher packing density of the bending converter can be obtained and a higher sound pressure can be obtained relative to the cross-sectional area of ​​the pipe, wherein a larger acoustically effective surface of the acoustic device is generated.

[0033] In order to be able to use the acoustic device in a particularly efficient manner, the acoustic bending transducer system can receive and / or transmit acoustic signals via a fluid volume flow through the opening. The acoustic bending transducer system can thus be operated simultaneously as a receiver and / or transmitter of acoustic signals, which again significantly increases the flexibility during use of the acoustic device. Here, transmitting or receiving acoustic signals can occur alternately or continuously.

[0034] According to a preferred embodiment, the acoustic device further comprises: a control unit for controlling the individual bending transducers of the bending transducer system; and an energy supply for operating the acoustic device. In addition, due to the various options for miniaturization of the acoustic bending transducer system, other devices or components can be incorporated into it in a space-saving manner despite the low size of the acoustic device. This essentially contributes to improving the wearing comfort and user-friendliness of the acoustic device.

[0035] In order to achieve a particularly high flexibility in the use of the acoustic device, two or more acoustic bending transducer systems can be held in a housing, wherein a common plane layer of the two or more acoustic bending transducer systems is oriented in parallel. As a result, for example, the acoustic device can be arranged or manufactured in the form of a substrate stack, whereby highly complex structures can be realized at relatively low manufacturing costs. Furthermore, in this way, the acoustic device can also be easily adjusted in an individual manner. Finally, by stacking several acoustic bending transducer systems, higher sound pressures can be generated and / or a larger displayable frequency range can be covered.

[0036] Advantageously, the acoustic device may be constructed monolithically from several layers or substrates of different materials that are bonded or connected to each other via a common layer. For example, this may occur in the form of a cover wafer disposed above a common device wafer or a handle wafer disposed below a common device wafer.

[0037] In order to provide an acoustic device of particularly space-saving and compact form, the control unit and / or the energy supply source are arranged in a common plane layer of the bending converter system. Obviously, the control unit is configured for fluid dynamic attenuation, for signal processing, for wireless communication, for voltage conversion. The control unit may include sensors, software for storing data, etc., which are arranged individually or together in the same acoustic device, or alternatively separately from the acoustic device. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Embodiments according to the present invention will be discussed in more detail below with reference to the accompanying drawings. With regard to the schematic diagrams shown, it should be noted that the functional blocks shown can be considered as elements or features of the apparatus of the present invention and the corresponding method steps of the method of the present invention, and the corresponding method steps of the method of the present invention can also be derived therefrom. They show:

[0039] Figure 1 is a perspective view of a bending converter system according to an embodiment of the present invention;

[0040] Figure 2 yes Figure 1 A perspective view of an embodiment having a substrate plane;

[0041] Figure 3 is a perspective view of a bending converter system according to another embodiment of the present invention;

[0042] Figure 4 yes Figure 3 A perspective view of an embodiment having a substrate plane;

[0043] Figure 5 It is a cross-sectional diagram of the ear canal, eardrum and earpiece of the human ear;

[0044] Figure 6a is a perspective view of elements of a bend transducer system in an excited state according to an embodiment of the present invention;

[0045] Figure 6b According to an embodiment of the present invention Figure 6a A perspective view of an element of a bend converter in another excited state;

[0046] Figure 7 is based on Figure 6a A cross-sectional view of a bending converter along section A of an embodiment of the present invention;

[0047] Figure 8 is a perspective view of a bending converter system according to another advantageous embodiment of the present invention;

[0048] Fig. 9 is a cross-sectional view of a bending converter according to another advantageous embodiment of the invention. DETAILED DESCRIPTION

[0049] Before discussing embodiments of the present invention in more detail below with reference to the accompanying drawings, it should be noted that the same, functionally equivalent or equivalent elements, objects and / or structures in different drawings are provided with the same or similar figure labels in the different drawings, so that the descriptions of these elements shown in different embodiments are interchangeable or applicable to each other.

[0050] Figure 1A perspective view of a bending converter system in the form of a layered device 100 according to an embodiment of the invention is shown, the layered device 100 comprising a first bending converter system 1 and a second bending converter system 2 stacked on top of each other. The device 100 may comprise further bending converter systems, which are arranged at the bending converter system 1 and / or at the bending converter system 2, for example in a layered manner. The bending converter system 1 or the bending converter system 2 comprises several bending converters 3, 4 having the same or different predefined lengths. On the surface of the bending converter system 1, an arrangement of bending converters 3, 4 of different lengths is exemplarily shown. Here, the bending converter 3 indicated by the solid line is longer than the bending converter 4 indicated by the short dashed line. In the present embodiment, both the bending converter system 1 as well as the bending converter system 2 are configured in an L-shaped manner, so that two bending converter systems 1 and / or 2 stacked on top of each other are stacked into an L-shaped device 100. The individual branches of the L-shaped device 100 have different lengths. In the region of the shorter branches of the L-shaped device 100, further bending converters 4 and bending converters 5 having a third length are arranged, which are indicated by dash-dotted lines. The lengths of the individual converters 3, 4 and 5 are, for example, 1000 μm to 4000 μm for the bending converter 3, 500 μm to 2000 μm for the bending converter 4, and 100 μm to 1000 μm for the bending converter 5. According to a preferred embodiment, the length ratios of the individual converters 3, 4 and 5 can be selected, for example, as follows: the length ratio of the bending converter 3 to the bending converter 4 is between 1:1.5 and 1:3; the length ratio of the bending converter 3 to the bending converter 5 is between 1:1.5 and 1:3; or the length ratio of the bending converter 4 to the bending converter 5 is between 1:1.5 and 1:3.

[0051] In the present embodiment, each bending converter system 1 or 2 consists of bending converters 3, 4 and 5, which are arranged parallel to each other in the plane of the bending converter system 1 or the bending converter system 2, wherein each bending converter 3, 4 and 5 is oriented along the longer branch of the L-shaped device 100. On the front side in the longitudinal direction of the device 100, an opening 13 is provided to allow a cavity (not shown here) included in the bending converter system 1 or the bending converter system 2 to be connected to the environment. Due to the L-shape of the device 100, each bending converter 3, 4 and 5 is arranged so that the short bending converters 4, 5 are arranged in the shorter branches of the L-shaped device 100, wherein the longer bending converter 3 is arranged in the longer branch of the L-shaped device.

[0052] In this embodiment, the bend converters 3, 4 and 5 are oriented along the longest side of the device. In contrast thereto, embodiments may also include an orientation of the bend converters along the shortest side of the bend converter system 1 and / or 2 or of the device 100. Thus, the opening 13 is then not arranged in the region 13, but always in the region of the clamps to which the bend converters 3, 4 are clamped on both sides, or in the region of the clamps 14 and the freely movable end of the cantilevered bend converter 5.

[0053] The bending transducers 3, 4 and 5 are arranged such that the short bending transducer 5 is arranged close to the opening 13. On the one hand, this leads to the advantage that a higher packing density can be achieved in the bending transducer system 1 and / or 2 and this leads to a higher sound pressure. On the other hand, resonances can be prevented, which has a positive effect on the sound quality.

[0054] In the present embodiment, the control unit 21 is arranged adjacent to the layered device 100, so that the control unit 21 complements the device 100 into a rectangular form, complementary to the L-shape of the device 100. Thereby, the existing installation space available between the branches of the L-shaped device 100 is utilized, which results in a particularly compact form.

[0055] Embodiments are not limited to an L-shaped configuration of the outer dimensions of the device. Other embodiments are not limited to the illustrated arrangement of the bending converters 3, 4 and 5, and in fact the arrangement may be different for each bending converter system 1 or 2 (see Fig. 9 ).

[0056] Figure 2 Shown in perspective Figure 1 In addition, a substrate plane 9 of the substrate layer is shown, which extends parallel to the substrate layer. Furthermore, a common movement plane 10 is shown which is formed by the movement directions 6, 7 and 8 of the respective bending converters, wherein the deformable elements of the bending converters 3, 4 and 5 oscillate coplanarly in a common planar substrate layer or movement plane 10. The movement plane 10 and the substrate plane 9 are arranged parallel to each other.

[0057] Figure 3 An embodiment of a device 100 with two stacked bend transducer systems 1 and 2 having an oval outer shape is shown in a perspective view. The opening 13 is preferably arranged in the region of a clamp 14 to which the bend transducers 3, 4 are clamped on both sides, or in the region of the clamp 14 and the freely movable end of the cantilevered bend transducer 5. An advantage of the oval outer geometry or shape of the device 100 is that the device 100 can be arranged in an inclined manner in a cylindrical or almost cylindrical housing of an ultra-mobile terminal device.

[0058] This embodiment shows an arrangement of the bend converters 3, 4 and 5 along the longest orientation of the elliptical device geometry. In the same way, embodiments may include deviating orientations of the bend converters 3, 4 and 5, or may include orientations of the bend converters 3, 4 and 5 that deviate therefrom. Furthermore, embodiments may include different orientations of the bend converters 3, 4 and 5 for each layered bend converter system 1 or 2, 2+n.

[0059] Other preferred embodiments are not limited to this elliptical shape and are adapted or adaptable to given spatial conditions and acoustic boundary conditions to obtain the maximum sound pressure.

[0060] Figure 4 Shown in perspective Figure 3 In addition, a substrate plane 9 extending parallel to the substrate layer is shown, wherein the deformable elements of the bending converters 3, 4 and 5 oscillate coplanarly in a common planar substrate layer or displacement plane 10. In addition, it is shown that the displacement plane 10 is formed by the displacement directions 6, 7 and 8 of the respective bending converters. The displacement plane 10 and the common planar substrate layer or substrate plane 9 are arranged parallel to each other.

[0061] Figure 5 The ear canal 31, the eardrum 32 and the earpiece 30 are shown in a cross-sectional view. It can be seen that the ear canal has a cylindrical geometry or shape. 101 indicates the external dimensions of the ultra-mobile terminal device, for example, the outer sleeve of its shell, which is suitable for the ear canal 31 and essentially seals the ear canal 31 relative to the environment. Such a shell 101 can be suitable for each user, but must be produced separately in an expensive, mainly additive and slow method. However, they allow the ultra-mobile terminal device to be in the best position in the ear canal 31. The embodiment can also have a simplified geometry, which is different from the individually adapted geometry manufactured in a cheap method (e.g., injection molding method). In the ear canal, these geometries do not have the best fit of the ultra-mobile terminal device or its shell 101, which is why high sound pressure with high sound quality is required to compensate for these inaccuracies. The arrangement of the device 100 or the bending transducer system 1 or 2 tilted relative to the longitudinal axis 11 of the housing 101 allows an increase in the acoustically active surface of the device 100 or the bending transducer system 1 or 2, on the one hand, for arranging a greater number of bending transducers 3, 4 and 5 in the bending transducer system 1 or 2 and / or for integrating longer bending transducers 3, 4 and 5 in the bending transducer system 1 or 2. The device 100 or the bending transducer system 1 or 2 is tilted relative to the longitudinal axis 106 about a transverse axis 105 of the ultra-mobile terminal device, wherein the tilt angle α between the movement plane 10 and the longitudinal axis 106 is in the range between 90° and 180°, preferably in the range between 150° and 170°, particularly preferably 160°.

[0062] By arranging the actuator relative to the housing axis, the deformable element is positioned anti-parallel relative to the orientation of the ear drum. This minimizes resonances in the ear canal.

[0063] The embodiments are not limited to the illustrated tilting about the transverse axis of the housing 101. Obviously, the device 100 may also be tilted about the longitudinal axis 106 and the vertical axis 107 of the housing 101.

[0064] Figure 6a Elements of a device 100 ′ in an activated state according to an embodiment of the invention are shown in a perspective view.

[0065] Specifically, Figure 6a A portion of the device 100 ′ of a substrate is shown in a perspective and highly simplified view, without the cover wafer 18 and the handle wafer 19 being shown.

[0066] The acoustic device can advantageously be constructed monolithically from several layers or substrates of different materials connected or bonded via a common layer. For example, this can occur in the form of a cover wafer 18 arranged above a common device wafer 20 or a handle wafer 19 arranged below the common device wafer 20.

[0067] The cavity 11 is formed by partially removing material from the device wafer 20, wherein the cavity is defined by the boundary 17 and the corresponding movable elements or electrodes of the bend transducers 32, 34 and 42, and by the substrate in the region of the fixture 14. Embodiments include alternative boundaries 17 of the cavity 11. On the one hand, the boundary 17 may be firmly connected to the substrate, and on the other hand, the boundary 17 may consist of an adjacent electrode of another bend transducer system 100' (formed by other bend transducers 3, 4 and 5).

[0068] In this embodiment, the bending transducers 32, 34, 42 and 31, 32 and 41 are shown clamped on both sides and connected to the substrate via respective clamps 14. Embodiments also include cantilevers which have the advantage of larger deflections of the freely movable end compared to two-sided clamps.

[0069] The bending transducers 3, 4 and 5 can be cantilevered or clamped on both sides in the bending transducer system 1 and / or 2. Here, it is useful to suspend the shorter bending transducers 4, 5 arranged in the region of the opening 13 and to clamp the longer bending transducer 3 arranged towards the center of the component on both sides. Since the shorter cantilevered bending transducer 5 is characterized by a favorable ratio of mass to bending transducer length, this advantageously leads to a larger oscillation amplitude of the shorter cantilevered bending transducer 5 at higher frequencies.

[0070] Furthermore, the basic functional principle of interaction with a volume flow, for example for sound generation or for pumping a fluid, is shown in such a bend transducer system 1 and / or 2. In a first time interval, the bend transducers 31, 32, 41 and the bend transducers 32, 34 and 42 move in the direction of the opposite boundary 17 of the cavity 11, thereby reducing the volume within the cavity 11. The volume flow 16 generated by this volume reduction transports the fluid contained in the cavity 11 out of the cavity 11 through the opening 13.

[0071] In such a bending converter system 1 and / or 2, Figure 6b The basic functional principle of interaction with a volume flow (e.g. for generating sound or for pumping a fluid) is also shown. During the second time interval, the bending transducers 31, 32, 41 and the bending transducers 32, 34 and 42 move away from the opposite boundary 17 of the cavity 11, thus increasing the volume of the cavity 11. The volume flow 16 generated by this volume increase delivers the fluid through the opening 13 into the cavity 11.

[0072] Alternative embodiments do not include a border 17 that is firmly connected to the substrate, but include other bend converters, which may be cantilevered or clamped on both sides and are not shown herein. In this case, in a first time interval, adjacent bend converter systems 1 and 2 move away from each other to increase the volume of the cavity 11 and move towards each other to decrease the volume of the cavity. Further developments of the embodiments may include a combination of borders 17 that are firmly connected to the substrate and / or not firmly connected to the substrate.

[0073] Figure 7 Shows Figure 6a sectional view of a device 100' along a section A. Here, a handle wafer 19 and a cover wafer 18 are shown, which form the vertical limitations of the cavity 11 which are limited by the bend converters 31, 32 and the boundary 17 in the area of ​​the device wafer 20. The structure is a stack of layers, wherein the individual layers are connected to each other in a mechanically fixed manner and in particular in a firmly bonded manner. These layers are not shown in the figures. The layered arrangement of the conductive layers allows a simple configuration, since the cavity 11 can be obtained by simply removing it from the layer 20 and the bend converter structure can be maintained by appropriate adaptation of the production process. Alternatively, the bend converter structure can also be arranged completely or partially in the cavity 11 by other measures or processes, for example by generation and / or positioning in the cavity 11. In this case, the bend converter structure can be formed in a different way compared to the part of the layer 20 remaining in the substrate, i.e. can comprise a different material.

[0074] Figure 8An alternative embodiment of a layered device 100 with an upper bend converter system 1 is shown in a perspective view, the upper bend converter system 1 comprising vertically arranged openings 131 in a cover wafer 181 for connecting the cavity 11 to the environment. A second bend converter system 2 is arranged below the first upper bend converter system 1 and comprises a laterally arranged opening 13 in a device wafer 20. The embodiments are not limited to the system of two bend converter systems 1 and 2 shown, in fact only one bend converter system 1 or 2 or a plurality of bend converter systems 1, 2, ... may be arranged. A control unit 21 is arranged in close proximity, which control unit 21 is part of the device 100 and results in a limitation of the available installation space for the bend converter system 1 and which is connected to a bend converter system (not shown). Further openings in the handle wafer 19 of the upper bend converter system 1 may be arranged such that they are connected to openings in the cover wafer 18 of the second bend converter system 2. In an embodiment, when looking forward through Fig. 9 , the processing wafer 19 of the first bend converter system 1 may be omitted, as the device wafer 20 ′ of the second bend converter system 2 may take over this function.

[0075] Fig. 9 An embodiment of an alternative device 100" having a top bending transducer system 1 (including vertically arranged openings 131 in the cover wafer 18) is shown in a cross-sectional view. In this embodiment, the device wafers 20 and 20' are mechanically connected, specifically, firmly bonded to each other via a common substrate layer 22 representing the cover wafer and the handle wafer. This embodiment exemplarily shows how the openings 131, 13'1, 13"1 can be arranged in the cover wafer, the handle wafer or the device wafer to obtain an optimal orientation with respect to the sound direction. Therefore, the sound direction can be determined by the volume flow generated by the movement of the deformable elements or bending transducers 31, 32, 3'1 and 3'2 of the device 100" that interacts with the environment.

[0076] In the following, further possible embodiments according to the invention will be described. In summary, a bend transducer 3, 4 and 5, which may be installed, for example, in a hearing aid, or a bend transducer system 1 and / or 2 comprising one or several such bend transducers 3, 4 and 5, or a device 100, 100', 100" comprising one or several such bend transducer systems 1 and / or 2 may be considered as:

[0077] 1. Bending converter system

[0078] o having outer dimensions adapted to the surrounding geometry, and the surrounding geometry includes a longitudinal axis that generally corresponds to the direction of sound

[0079] o includes bending transducers of varying lengths, consisting of deformable elements arranged in a cavity and connected to a substrate

[0080] o The deformation of the deformable element occurs in the plane of the substrate (in-plane) transverse to the lateral direction

[0081] o comprises a plurality of deformable elements, the respective movement directions of which form a common movement plane in the substrate plane

[0082] o Deformable elements with different lengths to achieve different maximum deflections

[0083] o Arrangement of bend converters of different lengths according to the available space, so that the area usage formed by the movement plane and the outer dimensions of the bend converter system is maximized

[0084] o and the plane of movement is inclined at least by an angle relative to the longitudinal axis 106 of the surrounding geometry.

[0085] 2. The short bend converter is arranged in the opening area,

[0086] 3. Long curved converters are placed in the center / where space is available

[0087] 4. The bending converter system tilts around the lateral axis of the surrounding geometry.

[0088] 4.1 The angle of the displacement plane 10 relative to the longitudinal axis 106 of the surrounding geometry is between 90° and 180°, preferably between 150° and 170°, and particularly preferably 160°.

[0089] 5. In an embodiment, the bending converter system is tilted about the longitudinal and / or vertical axis of the surrounding geometry

[0090] Comparable angles between 5.1 and 5.1

[0091] 6. In an embodiment, the short bending transducer arranged in the opening area is clamped on one side (cantilevered) and the long bending transducer is clamped on both sides.

[0092] 6.1 Clamping on one side is possible for bend transducers shorter than about 2000 μm 6.2 Clamping on both sides is possible for bend transducers longer than about 1000 μm 6.3 In a bend transducer system, any combination of bend transducers clamped on one side (cantilever) or clamped on both sides is possible, the goal is always high sound pressure with a wide frequency range

[0093] 7. In addition, the device including the bending converter system having the above characteristics may also include other devices:

[0094] Device for dynamic attenuation of fluids

[0095] Devices for signal processing

[0096] Devices for wireless communication

[0097] Devices for voltage conversion

[0098] ·sensor

[0099] ·software

[0100] Devices for storing data

[0101] Devices for capacity provisioning

[0102] 8. Headphones comprising at least one device having a bending transducer system of the above characteristics, wherein:

[0103] The outer dimensions of the 8.1 headphones almost correspond to the inner dimensions of the ear canal

[0104] 8.2 The earphones are configured so that when the user has inserted the earphones the device is placed in the ear canal

[0105] 8.3 The earphones are configured so that they almost completely close the ear canal

[0106] The 8.4 earphones are configured so that their external dimensions do not correspond to the external dimensions of a user's ear canal, but can therefore be produced in large quantities cost-effectively.

[0107] Furthermore, it is up to the person skilled in the art to arrange the bending transducer system as a sound transducer system. The technical teaching addressed herein discloses to the person skilled in the art how multiple bending transducers must be arranged to obtain high acoustic quality while having a wide frequency range feature in a limited predefined installation space.

[0108] Furthermore, a person skilled in the art can infer the technical teachings how a movement plane can be formed by a plurality of movement directions and how the movement plane can be tilted relative to the longitudinal and / or transverse and / or vertical axis of the space surrounding the sound transducer system.

[0109] Predefined spaces are geometries caused, for example, by the ear canal, other sensors or the following system technologies:

[0110] System technology for fluid dynamic attenuation

[0111] System technology for signal processing

[0112] System technology for wireless communications

[0113] System technology for voltage conversion

[0114] System technology used to store data

[0115] System technology for energy supply

[0116] Advantageously, short bending transducers of a bending transducer system will be arranged where little space is available and / or in the region of openings connecting the cavity to the environment. These openings are in the region of the outer limits of the bending transducer system. On the other hand, long bending transducers are mainly arranged in the center of the bending transducer system. This has the advantage that the available space is utilized optimally, a high packing density of the individual bending transducers is obtained, and thus an increase in the sound pressure level. Furthermore, long bending transducers enable lower resonance frequencies to be achieved due to their low stiffness.

[0117] Short bending transducers are characterized by a relatively high stiffness, which enables high resonance frequencies. As long as these bending transducers are arranged in the area of ​​the opening connecting the cavity and the environment, resonances can be prevented, thereby improving the sound quality.

[0118] Advantages of an oblique arrangement in a tubular space (eg, the ear canal).

[0119] The ear canal is roughly cylindrical, with dimensions of L×D=25 mm×0.7 mm (Wiki).

[0120] Therefore, the lateral acoustic resonance (λ / 2) of the closed ear canal is T ≈235kHz, the corresponding longitudinal resonance is at υ L ≈6.6kHz.

[0121] The earphone membrane in the "normal, i.e. radial" orientation is oriented by the longitudinal mode in υ L ≈6.6kHz and thus produces an unwanted audible additional resonance.

[0122] The earphone membrane in the "axial" position is driven only by the transverse mode in υ T = 235kHz. This is much better since it is acoustically completely uncorrelated. Obviously, the size of the bend transducer system (like the membrane) will be chosen so that the low eigenfrequencies of the membrane do not interfere. Therefore, the size of the bend transducer system should not be too large. At 60° inclination, the eigenfrequencies of an ideal membrane are about 2×6.6kHz=13.2kHz. According to all known information about "real existing headphones", this is good.

[0123] Due to the inclined arrangement of the bending transducer system, a larger footprint of the bending transducer system can be arranged in the available space (on which longer or more bending transducers can again be arranged). By using a greater number of bending transducers, higher sound pressures can be achieved.

[0124] Another advantage is that the openings can be optimally arranged in the direction of the sound direction given by the outer dimensions. Figure 8 A vertically arranged opening is shown which is arranged almost in the direction of the sound when the device is arranged in an inclined manner in the ear canal.

[0125] Therefore, this application describes further developments with respect to optimizing the amount of sound (sound pressure level) and the quality of sound that a device can produce in a specific environment.

[0126] The high integration requirements concern the overall adaptability to the existing installation space as well as the system design of several components.

[0127] In ultra-mobile end devices (e.g. wearables, smart watches), for example, energy storage devices and possibly other HMI components (tactile surfaces, displays) are subject to strict restrictions on the design of the installation space (cylindrical / cuboid or area-extending / plate-shaped). In order to still achieve a minimum installation space, the sound converter needs to be matched to the remaining installation space and in such a way that a high volume is achieved.

[0128] Additionally, when designing a system (ultra-mobile devices, such as ear-worn devices or wearables in general), the sound quality aspect may not be ignored. In particular, by a specific design of the sound transducer group, a sound generation adapted to the geometrical environment with respect to the sound emission or radiation can be obtained. A key driver is the frequency-dependent effect, where interfering resonances occur especially at high frequencies.

[0129] Utilizing the present invention, both the sound quality and the volume can be significantly improved.

[0130] The principle of the inventive bending converter is based on NED (Nano Electrostatic Drive) and is described in WO 2012 / 095185 A1. NED is a novel MEMS (Micro Electro Mechanical System) actuator principle. The basic principle is that a silicon beam is moved laterally in a plane (the substrate plane defined by a silicon disk or wafer). Here, the silicon beam connected to the substrate in a cavity interacts with a volume flow. Furthermore, the device comprises an electronic circuit arranged in one layer of the layer stack, wherein the electronic circuit is connected to the electromechanical bending converter and is configured to deflect the bending converter due to an electrical signal.

[0131] Reference numerals list

[0132] 1 First bending converter system

[0133] 2. Second Bend Converter System

[0134] 3. First length first bending converter

[0135] 4 second length second bend converter

[0136] 5 Third length third bend converter

[0137] 6 Movement direction of the first bending converter

[0138] 7 Movement direction of the second bending converter

[0139] 8 The third bending converter movement direction

[0140] 9 Substrate plane

[0141] 10 Moving the plane

[0142] 11 Cavity

[0143] 12 Angle between the moving plane and the longitudinal axis

[0144] 13 Opening

[0145] 14. Fixture

[0146] 15 Cavity Boundary

[0147] 16 Volume flow

[0148] 17 Edge of cavity

[0149] 18 Cover wafer

[0150] 19 Processing wafer

[0151] 20 device wafers

[0152] 21ASIC

[0153] 22 Common substrate layer

[0154] 30 Earpiece

[0155] 31 Ear canal

[0156] 32 Tympanic membrane

[0157] 100 devices

[0158] Part of 100' equipment

[0159] 101 External geometry of ultra-mobile terminal equipment, e.g. housing

[0160] 102 Length of the device

[0161] 103 Width of device

[0162] 104 Thickness of the device

[0163] 105 Horizontal axis of ultra-mobile terminal equipment

[0164] 106 Ultra-mobile terminal device vertical axis

[0165] 107 Vertical axis of ultra mobile device

[0166] 108 angle α.

Claims

1. An acoustic bending transducer system (1, 2), comprising: A plurality of bending transducers (3, 4, 5) configured so that the deformable elements (31, 32, 41; 32, 34, 42; 31, 32, 3'1, 3'2) of the bending transducers (3, 4, 5) oscillate coplanarly in a common plane layer (10), wherein the plurality of bending transducers (3, 4, 5) have different resonant frequencies and the deformable elements (31, 32, 41; 32, 34, 42; 31, 32, 3'1, 3'2) have a common longitudinal axis and different expansions along the common longitudinal axis, the common longitudinal axis being transverse to the oscillation direction of the deformable elements (31, 32, 41; 32, 34, 42; 31, 32, 3'1, 3'2); one or several cavities (11) in which the bending converters (3, 4, 5) are arranged; and An opening (13; 131, 13'1, 13''1) through which a fluid volume flow (16) interacting with the plurality of bending converters (3, 4, 5) can pass.

2. The acoustic bending transducer system (1, 2) according to claim 1, wherein: The deformable element (31, 32, 41; 32, 34, 42; 31, 32, 3'1, 3'2) of at least one bending converter (3, 4, 5) is deformable electrostatically, piezoelectrically or thermomechanically.

3. The acoustic bending transducer system (1, 2) according to claim 1, wherein: At least a first subset of at least one first bending transducer (5) comprises at least one cantilevered deformable element, and At least a second subset of at least one second bending converter (3, 4) comprises a deformable element (31, 32, 41; 32, 34, 42; 31, 32, 3'1, 3'2) clamped on both sides.

4. The acoustic bending transducer system (1, 2) according to claim 3, wherein: The at least first subset of at least one first bending transducer (5) comprises an average higher resonance frequency than the at least second subset of at least one of the second bending transducers (3, 4), or the at least second subset of at least one of the second bending transducers (3, 4) comprises an average higher resonance frequency than the at least first subset of the at least one first bending transducer (5).

5. The acoustic bending transducer system (1, 2) according to claim 3, wherein: The at least first subset of at least one first bending transducer (5) comprises a length which is shorter on average than the at least second subset of at least one second bending transducer (3, 4).

6. The acoustic bending transducer system (1, 2) according to claim 1, wherein: Each bending converter (3, 4, 5) borders at least one cavity (11) and is accessible via at least one opening (13; 131, 13'1, 13''1) for the passage of the fluid volume flow (16).

7. The acoustic bending transducer system (1, 2) according to claim 1, wherein: The outer dimension of the bending converter system (1, 2) along the common longitudinal axis is between 750 μm and 2000 μm.

8. The acoustic bending transducer system (1, 2) according to claim 1, wherein: The bending converter system (1, 2) has a longitudinal elliptical outer surface coplanar with the common plane layer along the common longitudinal axis, a longitudinal rectangular outer surface coplanar with the common plane layer along the common longitudinal axis, or a longitudinal polygonal outer surface coplanar with the common plane layer along the common longitudinal axis.

9. The acoustic bending transducer system (1, 2) according to claim 1, wherein: The bending converters (3, 4, 5) are divided into groups of one or several bending converters (3, 4, 5), wherein, in a group with several bending converters (3, 4, 5), the several bending converters (3, 4, 5) are arranged one after another along the common longitudinal axis; and / or wherein: In a group of several bending converters (3, 4, 5), the several bending converters (3, 4, 5) in the common planar layer (10) are arranged side by side transversely to the common longitudinal axis.

10. An acoustic device comprising: An acoustic bending transducer system (1, 2) having at least one bending transducer (3, 4, 5), the bending transducer (3, 4, 5) comprising at least one deformable element (31, 32, 41; 32, 34, 42; 31, 32, 3'1, 3'2) arranged in a cavity (11); and an opening (13; 131, 13'1, 13''1) through which a fluid volume flow (16) interacts with the movement of the bending converter (3, 4, 5) in the cavity (11); as well as A housing (101) adapted to be inserted into an ear canal, wherein the acoustic bending transducer system is held in the housing (101) such that the fluid volume flow (16) is oriented obliquely to the longitudinal axis of the ear canal and is arranged in the ear canal when the housing (101) is inserted into the ear canal; wherein the acoustic bending transducer system (1, 2) is the acoustic bending transducer system (1, 2) according to claim 1; and Therein, the acoustic bending transducer system (1, 2) is configured such that the fluid volume flow (16) flows in the plane of the common planar layer (10) of the acoustic bending transducer system (1, 2).

11. The acoustic device according to claim 10, wherein: The acoustic bending transducer system (1, 2) is held in the housing (101) so that a volume flow (16) of the fluid of the acoustic device passes through the opening (13; 131, 13'1, 13''1) of the acoustic bending transducer system (1, 2) at an angle of between 5° and 80°, between 10° and 40°, or between 15° and 30° relative to the longitudinal axis of the ear canal.

12. The acoustic device according to claim 10, wherein: The acoustic bending transducer system (1, 2) is capable of receiving and / or transmitting acoustic signals via the fluid volume flow (16) through the opening (13; 131, 13'1, 13''1).

13. The acoustic device according to claim 10, further comprising: A control unit for controlling the individual bending transducers (3, 4, 5) of the acoustic bending transducer system (1, 2); as well as A power supply source is provided for operating the acoustic device.

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