Microelectromechanical device and microelectromechanical loudspeaker

Abstract

The invention relates to a microelectromechanical device (1) for generating fluid pressure with a displacement structure (2), wherein the displacement structure (2) has a movable lamella (3, 3a, 3b) which can be deflected to generate the fluid pressure by means of a driveable connecting structure (7) acting on the lamella (3, 3a, 3b), and wherein the connecting structure (7) has a drive element (8) and a deflection element (9) connecting the lamella (3, 3a, 3b) to the drive element (8), wherein the deflection element (9) has a lower bending stiffness than the drive element (8) and is elastically deformable when the lamella (3, 3a, 3b) is deflected. The invention also relates to a microelectromechanical loudspeaker with such a microelectromechanical device (1).

Description

[0001] The invention relates to a microelectromechanical device and a microelectromechanical loudspeaker. State of the art

[0002] Microelectromechanical devices and loudspeakers, also known as microelectromechanical structures under the term “MEMS”, are disclosed, for example, in US 2021 / 0 297 787 A1, which describes a sound generation chip with a lamella, a coupling plate and a spring structure as well as an actuator for exciting the lamella.

[0003] WO 2021 / 144400 A1 discloses a MEMS transducer with an oscillatable lamella with vertical sections that can be excited to horizontal oscillations.

[0004] WO 2021 / 223886 A1 relates to a MEMS with a layer structure and a cavity arranged therein, in which an interaction structure arranged to be movable along a plane direction is formed.

[0005] DE 10 2019 203 914 B3 describes a MEMS with a movable layer arrangement in a cavity, which is moved along a substrate plane by an electrical potential between two of three beams arranged in the layer arrangement.

[0006] US 2012 / 0 018 244 A1 relates to a MEMS loudspeaker with a cavity defined by a lamella and an actuator for displacing or deforming the lamella in order to generate a pressure pulse.

[0007] GB 2 554 470 A discloses a MEMS device having a primary lamella rigidly bonded to a substrate and a secondary lamella in a plane above the primary lamella, the secondary lamella being mechanically coupled to the primary lamella. Disclosure of the invention

[0008] According to the features of independent claim 1, a microelectromechanical device for generating a fluid pressure with a displacement structure is proposed, wherein the displacement structure has a movable lamella which can be deflected to generate the fluid pressure by means of a drivable connecting structure acting on the lamella, and wherein the connecting structure has a drive element and a deflection element connecting the lamella to the drive element, wherein the deflection element has a lower flexural rigidity than the drive element and is elastically deformable upon deflection of the lamella.

[0009] In other words, a flexible, reversibly deformable deflection element for deflecting the slat is proposed, which enables a flexible coupling of the connecting structure to the slat, thus avoiding stiffening of the slat and reducing material stress on the slat. The deflection element of the connecting structure is designed to be flexible or flexible in such a way that a rotation of the slat during its deflection is transferred to the deflection element, and the deflection element is thereby elastically deformed. The deflection element can, in particular, be elastically deformable in an arcuate shape. The arcuate deformation is attributable to the rotation of the slat during its deflection and can also be referred to simply as the rotation of the deflection element.Elastic deformability refers to reversible deformability, in which the deflection element strives to return to its original shape after the deflected slat returns to its original position and thus after the slat twisting causing the deformation has ceased. The original shape can, for example, be a straight, elongated shape of the deflection element.

[0010] The connecting structure of the device is configured to deflect the slat in order to generate fluid pressure. In the present application, a connecting structure is understood to be a movable actuator element that is a component of an actuator system comprising a drive device and the connecting structure drivable by the drive device. The connecting structure serves to transmit force from a drive device to the slat. The connecting structure can be a so-called shuttle. The drive element of the connecting structure is the part of the connecting structure that is driven by the drive device, such that the drive element is moved along a predefined movement path in one movement direction. The drive device can be configured to be able to drive the connecting structure in opposite movement directions in order to be able to deflect the slat in opposite directions.The drive device can be, for example, an electrostatic, piezoelectric, or other suitable drive device, whereby the drive concept can be based, for example, on comb structures, electrostatic bending actuators (Nanoscopic Electrostatic Drive, NED), or micromuscles. The deflection element is connected to the drive element and is the part of the connecting structure that transfers the drive force of the drive device to the slat via a movement of the drive element and the deflection element. In the context of the present application, the term "connected" can refer in particular to a one-piece connection without additional form-fitting, force-fitting, or material-fitting connecting means.Due to the elastically deformable design of the deflection element, the drive force is transmitted to the slat in such a way that a deflection of the slat leads to an arc-shaped deformation of the deflection element and stiffening of the slat is avoided.

[0011] The lamella can be a flat, deflectable structure with a height and length several times greater than its width, wherein the height and length span a lamella plane that can be aligned vertically in the displacement structure, for example. The lamella can have a width of between 0.5 and 100 µm, in particular between 1 and 30 µm. The lamella can have a length of between 100 and 10,000 µm, in particular between 1,000 and 5,000 µm. The lamella can have a height of between 1 and 1,000 µm, in particular between 50 and 800 µm. The connecting structure can, in particular, be moved substantially in a drive direction perpendicular to the lamella plane in order to deflect the lamella. A lamella deflection generally leads to at least a local or section-wise twisting of the lamella.

[0012] It is proposed that the flexural rigidity of the deflection element be lower than the flexural rigidity of the drive element. In the context of the present application, flexural rigidity is understood as the product of a modulus of elasticity E and an area moment of inertia I. The modulus of elasticity E is to be understood as the effective modulus of elasticity, since the components of the displacement structure of the device can be made of anisotropic silicon and thus local fluctuations in the modulus of elasticity can occur. Suitable or favorable value ranges for the effective modulus of elasticity can be, for example, between 1 GPa and 400 GPa, in particular in a range between 120 GPa and 200 GPa.

[0013] In principle, it is possible to influence the flexural rigidity by using different materials and thus different elastic moduli of the drive element and the deflection element. However, since the deflection element and the drive element can advantageously be made of the same material or at least of similar materials, in particular semiconductor materials, the reduced flexural rigidity can be influenced in particular by the geometric shape and design of the deflection element in order to reduce its area moment of inertia. For example, the deflection element can be designed as a thin fin with a width several times smaller than that of the drive element. The deflection element can, for example, have a width between 0.5 and 100 µm, in particular between 1 and 50 µm. The deflection element can be made of a solid material.Alternatively or additionally, it is possible to provide the deflection element with a structure, for example with a micro-perforation, in order to specifically reduce the flexural rigidity of the deflection element.

[0014] The drive element has greater flexural rigidity than the deflection element. In other words, the deflection element can be flexible and the drive element rigid. This prevents any potential transmission of twisting of the deflection element or the lamella via the drive element to the drive device, and enables defined drive of the drive element with efficient power transmission. The greater flexural rigidity can be achieved in particular through the geometric shape and design of the drive element. The drive element can, for example, have a greater width than the deflection element, for example a width between 0.5 and 1500 µm, in particular between 50 and 500 µm. In other words, the connecting structure can be rigid on the drive side and flexible on the output side, whereby the drive side can be assigned to a drive device and the output side to the lamella.A height of the drive element and / or the deflection element can be, for example, between 0.5 and 600 µm, in particular between 5 and 60 µm.

[0015] The flexural rigidity of the drive element can, for example, be twice, three times, or four times the flexural rigidity of the deflection element. According to one embodiment, the flexural rigidity of the drive element can be at least five times the flexural rigidity of the deflection element. This reliably prevents twisting from being transmitted to the drive device via the drive element, given an elastically deformable design of the deflection element.

[0016] The displacement structure can also comprise multiple movable lamellae. For example, multiple movable lamellae can consist of at least two movable lamellae. A movable lamella can enclose a displacement volume with another movable lamella and / or with a fixed structure, for example, a support structure such as a frame, so that a deflection of the lamella leads to a change in the displacement volume and a fluid pressure is generated. The lamellae can, for example, be arranged periodically in succession on a support structure.

[0017] If the displacement structure has several movable lamellae, the connecting structure can be designed as a multiple connection structure configured for the simultaneous deflection of several lamellae. This increases the number of deflections per connecting structure movement and promotes simultaneous and uniform fluid pressure generation via the displacement structure. In principle, a deflection element can protrude from the drive element at each lamella in order to connect the drive element to the lamella by means of the deflection element. However, it can also be advantageous if the deflection element extends at a distance from the drive element and is connected to the drive element at predefined intervals. This achieves an advantageous additional coupling of the lamellae via the deflection element, which can contribute to increased stability of the displacement structure.In other words, in a non-deformed state, i.e., in a non-deflected state of the slats, the deflection element can run essentially parallel to the drive element. Deflection of, for example, periodically arranged slats can lead to multiple arcuate deformations of the deflection element in the area of ​​the slats, so that a periodic, wave-like deformation of the deflection element can occur between the slats.

[0018] The deflection element can be connected to the slat via a coupling point located between a slat center and a slat end. This can enable a favorable leverage effect, whereby a slight excitation of the deflection element can lead to a comparatively large deflection of the slat. The coupling point can, for example, be located in a range of ¼ to ¾ of the distance between the slat center and the slat end. The coupling point can, for example, be located essentially centrally between the slat center and the slat end. A slat center can, for example, refer to a geometric center of the slat. A slat end can, for example, refer to a fastening area of ​​the slat on a support structure.In the case of a lamella aligned vertically in the displacement structure, the deflection element can be connected to a lamella edge delimiting the lamella, wherein the coupling point can be located in a section of the lamella edge that lies between a central longitudinal axis of the lamella transverse to the lamella edge and the fastening region of the lamella on the support structure. In a deflected state of the lamella, the coupling point can be arranged, for example, in an inflection point region of a curve described by the deflected lamella. The coupling point can, for example, have a height between 0.01 and 20 µm, in particular between 0.1 and 3 µm. A width and a thickness of a coupling point can, for example, each be between 0.5 and 100 µm, wherein the width can, in particular, be half the width of the lamella and the thickness can, in particular, be half the width of the deflection element.

[0019] According to one embodiment, the drive element is connected to the deflection element by means of a connecting element. This allows a defined connection of the deflection element to the drive element. The connecting element can be designed, for example, as a connecting web extending between the drive element and the deflection element. According to one embodiment, the connecting element can partially insert into a recess in the drive element. This allows a compact embodiment of the connecting structure to be provided.

[0020] According to one embodiment, the connecting element can have a higher flexural rigidity than the deflection element. In other words, the connecting element can be a rigid connecting element. The connecting element can, for example, have a shorter length and / or a greater width than the deflection element. The connecting element can, for example, have a length between 0.5 and 500 µm, in particular between 6 and 100 µm, and a width between 0.5 and 100 µm, in particular between 1 and 30 µm. A higher flexural rigidity can prevent twisting of the deflection element or the lamella from being transmitted to the drive element.

[0021] A distance between two connecting elements can be, for example, between 5 and 4500 µm, in particular between 10 and 200 µm. A distance between a coupling point and the nearest connecting element can be, for example, between 5 and 4500 µm, in particular approximately ¼ of the distance between two connecting elements. A distance between two coupling points can be, for example, between 5 and 4500 µm, in particular between 10 and 200 µm. A distance between two lamellae can be, for example, between 5 and 4500 µm, in particular between 10 and 200 µm. According to one embodiment, the distances between two connecting elements, between two coupling points, and between two lamellae can be substantially equal. For example, a distance between a slat end of a slat and a coupling point on the same slat can be between 0.01·(l4 / 2) - 0.99·(l4 / 2), where l4 corresponds to the length of a slat.

[0022] According to one embodiment, two or more drive elements can also have at least one common deflection element and / or at least one common connecting element. This allows for a stable and reliable drive of the deflection element and a compact arrangement.

[0023] According to one embodiment, the deflection element can be elastically deformed in an arcuate manner, and the connecting element can be connected to a neutral section of the deflection element, wherein the neutral section is a region of an arcuate deformation of the deflection element, at which a tangent runs essentially parallel to the drive element. The arcuate deformation of the deflection element relates to a deflected state of the slat. In other words, the deflection element runs approximately parallel to the drive element in the region of the neutral section. Here, the expression "parallel to the drive element" refers to a longitudinal extent of the drive element, which can, for example, be the greatest extent of the drive element and run transversely to the slat. Relative to a deflected state of the slat and a deformed state of the deflection element, the twisting of the deflection element at the neutral section is minimized.This ensures that no twisting is transferred from the deflection element to the drive element. Furthermore, stiffening of the deflection element and thus potentially also of the slat by the connecting element is avoided. Ideally, the tangent can be applied to a neutral point of the neutral section, where the tangent runs parallel to the drive element. However, due to the extension of the connecting element, it cannot be connected at a point, but rather occupies a certain area around the neutral point, which is referred to here as the neutral section. The neutral section of the deflection element can, in particular, be spaced from a coupling point between the deflection element and the slat.If the displacement structure has multiple lamellae and the deflection element extends at such a distance from the drive element that the deflection element is deformed in a wave-like manner between the lamellae when the lamellae are deflected, a change in sign of the arcuate deformation of the deflection element occurs along the waveform through the lamellae. This creates at least one localized point with a zero twist to which the connecting element can be connected. In the case of a periodic arrangement of multiple lamellae and a connecting structure, the connecting element can be connected to the deflection element, for example, at a position of 1 / 4 ±15% or 3 / 4 ±15% of the lamella spacing.In principle, the connection can also be made to a neutral section of the deflection element if the multiple lamellae are arranged non-periodically or the displacement structure has only a single lamella, wherein the position is selected according to the individual lamella arrangement in such a way that the twisting of the deflection element at the connection point is minimized.

[0024] By connecting the deflection element to a neutral section by means of a connecting element, a deflection of the slat and a resulting deformation of the deflection element can result in the connecting element transmitting a slight residual transverse movement of the deflection element to the drive element. If, for example, the deflection element is deformed by a momentary slat deflection in such a way that a wave trough of the wave-shaped deformed deflection element is present on the connecting element, the deflection element exerts a slight compressive force on the connecting element, which causes the aforementioned residual transverse movement. Conversely, the residual transverse movement can also result from a tensile force of a wave crest of the deflection element on the connecting element. The residual transverse movement can be compensated by the connecting structure and / or the drive device, as will be explained below in connection with further embodiments.

[0025] According to one embodiment, the connecting element can have a lower flexural rigidity than the drive element. In other words, the connecting element can be a flexible connecting element. The connecting element can be elastically deformable, in particular elastically deformable in an arcuate manner. The flexural rigidity of the connecting element can, for example, substantially correspond to the flexural rigidity of the deflection element. The connecting element can, for example, have a width between 0.5 and 100 µm, in particular between 1 and 50 µm.

[0026] According to one embodiment, the deflection element can be elastically deformed in an arcuate manner and the connecting element can be connected to an arcuate section of the deflection element, wherein the arcuate section is a region of an arcuate deformation of the deflection element, at which a tangent runs substantially at an angle to the drive element. As a result, an arcuate elastic deformation of the deflection element can be transferred to the connecting element upon deflection of the slat. The arcuate deformation of the deflection element is related to a deflected state of the slat. The connecting element can, for example, be deformable with the same degree of deformation as the deflection element; for example, a radius of the arcuate deformation of the connecting element can have the same radius as the arcuate deformation of the arcuate section of the deflection element to which the connecting element is connected.

[0027] According to one embodiment, in the case of an arc-shaped elastic deformation, the connecting element can have an arc region and a neutral region adjoining the arc region, wherein the connecting element is connected to the drive element via the neutral region. In the neutral region, the twist of the connecting element transmitted from the deflection element to the connecting element is minimized. For example, a twist transmitted from the deflection element to the connecting element can decrease along the connecting element and, after a sufficient distance, reach a minimized deformation. For example, the connecting element can merge vertically into the drive element at its neutral region or be connected vertically to it. The connecting element can therefore, for example, be dimensioned in its length such that the connecting element merges into the drive element with little twist.This ensures that no torsion is transferred from the deflection element to the drive element. In addition, stiffening of the deflection element and thus possibly also of the slat by the connecting element is avoided. The low-twist connection of the connecting element to the drive element can alternatively be achieved or further improved if the connecting element is connected to the deflection element at a suitable position. This can, for example, be a position at which there is a twist of the deflection element when the slat is deflected, wherein the connecting element is configured such that the twist transferred to the connecting element is equal to the twist of the deflection element at the connection point. This makes it possible to compensate for the twist, which enables a low-twist connection of the connecting element to the drive element.In the case of a periodic arrangement of multiple lamellae and a connecting structure, the connecting element can be connected to the deflection element, for example, at a position of ½ ±15% of the lamella spacing or close to the coupling point, for example, at a position of 1 / 8 ±10% of the lamella spacing. The connection can also be made to a low-torsion section of the deflection element if the multiple lamellae are non-periodically arranged or the displacement structure has only a single lamella. The position is selected according to the individual lamella arrangement such that the torsion transmitted to the connecting element is equal to the torsion of the deflection element at the connection point.

[0028] According to one embodiment, the device can have a connecting structure group with connecting structures arranged parallel to one another, each having a drive element and a flexible deflection element connecting the slat to the drive element. This allows for a more uniform deflection of the slat. The connecting structure group can therefore, for example, jointly deflect the same slat, with the deflection elements being connected to the slat at different coupling points. The connecting structure group can be driven in the same direction, and thus displaceable in the same direction of movement when driven by the drive device. The connecting structure group can, for example, be designed as a connecting structure pair with two connecting structures, but connecting structure groups with more than two connecting structures are also conceivable.The connecting structures of the connecting structure group can be designed as multiple connecting structures in order to be able to deflect several slats simultaneously, so that the connecting structure group can be designed as a multiple connecting structure group. In a connecting structure pair, the drive elements can be arranged, for example, between the deflection elements of the connecting structure pair. The drive elements can also be designed as a common drive element of a connecting structure group, so that, for example, only one drive element with several, for example two, deflection elements can be formed in the connecting structure group. If the deflection elements of the connecting structures of the connecting structure group are connected to the drive elements by means of rigid connecting elements, the connecting elements can, for example, be arranged opposite one another.This allows any residual transverse movement transmitted from the connecting elements to the connecting structures to be counteracted and thus at least partially compensated. Alternatively, the connecting elements can be arranged, for example, along the drive elements, alternating at a position of 1 / 4 ±15% and 3 / 4 ±15% of the slat spacing. This allows any residual transverse movement transmitted from the connecting elements to the connecting structures to be rectified and thus more effectively compensated by the drive device.

[0029] According to one embodiment, the device can comprise a first lamella, a second lamella, and two connecting structure groups with connecting structures arranged parallel to one another, wherein a first connecting structure group is connected to the first lamella and a second connecting structure group is connected to the second lamella. This allows the drive force to be distributed among several connecting structure groups. Furthermore, improved displacement performance can be achieved. The high functional density also increases the cost-effectiveness of the device.

[0030] The first connecting structure group can be driven in the opposite direction to the second connecting structure group. This allows the first and second lamellas to be deflected in opposite directions, thus achieving increased displacement performance.

[0031] According to one embodiment, the connecting structures of the first connecting structure group can be arranged between the connecting structures of the second connecting structure group. This allows a uniform deflection of the first and second lamellas to be achieved.

[0032] According to an alternative embodiment to the previously described configuration, the connecting structures of the first connecting structure group and the connecting structures of the second connecting structure group can be arranged alternately one after the other. This allows the coupling points of the deflection elements on the slats to be placed at different distances apart, thereby enabling different leverage effects and different stiffnesses of the slats, thus allowing greater design freedom.

[0033] According to one embodiment, a drive device of the device can be configured to convert a residual transverse movement transmitted from the drive element to the drive device into a drive force acting on the drive element. For example, the residual transverse movement can be converted into drive force by means of a transmission or lever mechanism. For example, connecting structures or multiple connecting structures can be driven relative to one another. The connecting structures or multiple connecting structures can also be driven relative to a stator.

[0034] According to one embodiment, the connecting element can have a higher flexural rigidity than the deflection element, the connecting element can be connected to a neutral section of the deflection element, the tangent of which runs substantially parallel to the drive element at an arcuate deformation of the deflection element, the device can have a connecting structure group with connecting structures arranged parallel to one another, which have a drive element and each have a deflection element connecting the lamella to the drive element, and the device can have a first lamella, a second lamella and two connecting structure groups with connecting structures arranged parallel to one another, wherein a first connecting structure group is connected to the first lamella and a second connecting structure group is connected to the second lamella.This allows for a compact and efficient device with a high displacement capacity to be provided.

[0035] The device can, for example, be manufactured as a layered structure with multiple functional layers produced between two cover layers or wafers. For example, the lamella(s) can be arranged in a first functional layer and the connecting structure(s) in a second functional layer. The second functional layer can be arranged above and / or below the first functional layer. The coupling points with which the lamellae are connected to the connecting structures can extend between the first and second functional layers and, for example, form an intermediate coupling layer. The lamellae and / or the connecting structures can advantageously be made of a semiconductor material such as silicon or silicon compounds.

[0036] The displacement structure of the device can, for example, be designed to compress and expand air, so that the generated fluid pressure can be, for example, a sound pressure, and the device is suitable for use in an acoustic MEMS, for example, a microelectromechanical loudspeaker. According to other embodiments, the displacement structure can, for example, be designed as a pump or a valve for microfluidic applications.

[0037] The invention also relates to a microelectromechanical loudspeaker comprising a microelectromechanical device according to at least one of the above-described features, wherein the displacement structure is configured to generate sound pressure as fluid pressure, and which comprises a signal processing unit for applying and processing signals from the microelectromechanical device. The elastically deformable deflection element of the connecting structure of the loudspeaker device prevents rotation of the lamella deflected by the deflection element, and stiffening effects are avoided. This makes it possible to provide a microelectromechanical loudspeaker with a high and constant sound pressure level (SPL) over a wide frequency range, for example, between 20 Hz and 20 kHz.In addition, a high sound quality is achieved for the loudspeaker, which can be represented, for example, by low harmonic distortion (THD, total harmonic distortion).

[0038] In general, in the context of this application, the words “a / an”, unless expressly defined otherwise, are not to be understood as a number, but as an indefinite article with the literal meaning of “at least one”.

[0039] The invention permits various embodiments and is explained in more detail below using an exemplary embodiment with the accompanying drawings. They show: Fig. 1a-1b - a schematic basic principle of a lamella deflection by elastic deflection elements in a displacer structure of a microelectromechanical device; Fig. 2a-2b - a schematic plan view of a microelectromechanical device with a displacer structure according to a first embodiment; Fig. 3a-3b - a schematic plan view of a microelectromechanical device with a displacer structure according to a second embodiment; Fig. 4a-4b - a schematic plan view of a microelectromechanical device with a displacer structure according to a third embodiment; Fig. 5a-5b - a schematic plan view of a microelectromechanical device with a displacer structure according to a fourth embodiment in two variants; Fig. 6 - a schematic plan view of a microelectromechanical device with a displacer structure according to a fifth embodiment; Fig. 7a-7b - a schematic plan view of a microelectromechanical device with a displacer structure according to a sixth embodiment; Fig. 8 - a schematic plan view of a microelectromechanical device with a displacer structure according to a seventh embodiment with geometric references; Fig. 9a-9d - a schematic top view and cross-sectional views of the microelectromechanical device with a displacer structure according to the first embodiment; Fig. 10a-10b - schematic plan views of a microelectromechanical device with a displacer structure according to an eighth embodiment; Fig. 11a-11b - schematic plan views of a microelectromechanical device with a displacer structure according to a ninth embodiment in two variants; Fig. 12a-12b - schematic plan views of a microelectromechanical device with a displacer structure according to a tenth embodiment in two variants; Fig. 13 - a schematic diagram of a microelectromechanical loudspeaker with a microelectromechanical device.

[0040] The Fig. 1a and Fig. 1b schematically show a basic principle of a microelectromechanical device 1 with a displacement structure 2, which has several lamellae 3, which can be deflected by means of elastically deformable deflection elements 9. The Fig. 1a and Fig. 1b are intended to illustrate a basic principle of elastic deflection, so that no drive element 8 has been drawn here as can be seen in the following figures. Fig. 1a shows the slats 3 in a non-deflected state, which can be referred to as the initial position. Fig. 1b shows the slats 3 in a deflected state. Fig. 1a and Fig. 1b represents a top view of the displacement structure 2, whose slats 1 are aligned vertically in the displacement structure 2, so that the viewer's view is directed to a slat edge delimiting the slat plane. The slats 3 are held by a frame-shaped support structure 18. The slats 3 were Fig. 1a to Fig. 1b is transferred from the initial position into the deflected state by a deflection movement L. As shown, two arc-shaped, elastically deformable deflection elements 9 are connected to the slats 3 via coupling points 6. The coupling points 6 are each located approximately centrally between a slat center 4 and a slat end 5. By designing the deflection element 9 as an elastically deformable deflection element 9, a twist V of the slat 3 is transferred to the deflection element 9. This prevents stiffening of the slat 3 at the coupling point 6 and reduces the stress on the slat 3 by the deflection element 9. The twist V leads to a wave-like deformation of the deflection element 9 between the slats 3. The deflection element 9 regularly has positions of a change in sign of the twist V, at which a point with little twist, in simple terms a neutral section 17, is present.Put simply, the neutral section 17 runs approximately parallel to a drive element 8. In . Fig. Figure 2a shows how, at the neutral section 17, an exemplary tangent T of the arcuate deformation can run essentially parallel to a drive element 8 of the displacement structure 2. The neutral sections 17 can represent advantageous positions for connecting a connecting element 10, explained in the further figures, for connecting the deflection element 9 to a drive element 8.

[0041] The Fig. 2a and Fig. 2b show a microelectromechanical device 1 for generating a fluid pressure according to a first embodiment. The device 1 has a displacement structure 2 with movable lamellae 3, which enclose a variable displacement volume that can be filled with a fluid with the holding structures 18 and adjacent lamellae 3 and can generate a fluid pressure by changing the displacement volume. The lamellae 3 can be driven by means of connecting structures 7 arranged parallel to one another, wherein the connecting structures 7, according to the illustrated first embodiment, are designed as a connecting structure group 11 formed by a connecting structure pair. The connecting structures 7 are also designed as multiple connecting structures, so that each connecting structure 7 is configured to deflect several lamellae 3. The connecting structure group 11 is thus designed as a multiple connecting structure group.The connecting structures 7 can be driven in opposite directions, so that the slats 3 can be deflected from their starting position in opposite directions. Each connecting structure 7 of the connecting structure group 11 has a drive element 8 and a continuous deflection element 9, the flexural rigidity of which is lower than the flexural rigidity of the drive element 8. In other words, the drive element 8 is rigid and the deflection element 9 is flexible. The drive element 8 and the deflection element 9 are connected to one another here via connecting elements 10, which have a higher flexural rigidity than the deflection element 9, i.e., in simplified terms, are rigid. In principle, it is also conceivable to combine the two drive elements 8 into one drive element 8 and to design them as a common drive element 8, as will be explained later. The connecting structures 7 serve to transmit force from, for example, a . Fig. 2b, which has an optional stator 16, onto the lamination 3. The drive elements 8 of the connecting structures 7 are driven in the same direction by the drive device 12, so that they execute a connecting structure movement A in the same direction. By designing the drive elements 8 as drive elements 8 with a higher flexural rigidity than the deflection elements 9, a potential transmission of twists V to the drive device 12 is avoided. By designing the connecting elements 10 as connecting elements 10 with a higher flexural rigidity than the deflection elements 9, a potential transmission of twists V to the drive device 12 can also be avoided.

[0042] As in connection with Fig. As already explained in Figure 1, the connecting elements 10 are connected to the deflection element 9 at neutral sections 17. This prevents stiffening of the slat 3 by the connecting element 10. Simply put, the neutral section 17 runs approximately parallel to a drive element 8. Fig. 2a shows how an exemplary tangent T of the arcuate deformation can run essentially parallel to a drive element 8 of the displacement structure 2 at the neutral section 17. Viewed from top to bottom, Fig. 2a, the connecting elements 10 of the connecting structure group 11 are alternately connected to the deflection element 9 on both sides of the drive elements 8 at a position of approximately ¼ and ¾ of the distance between the slats 3. This results in a slight, rectified residual transverse movement Q of the drive elements 8, which can be compensated by the drive device 12. In Fig. 2b, the connecting elements 10 are arranged opposite one another, so that an opposing residual transverse movement Q is present in the drive elements 8, allowing them to at least partially compensate for each other. A force F from the drive plane can act back on the drive device 12. The residual transverse movements Q, indicated by arrows in the figures, represent a momentary direction of movement due to the existing deflection of the slats 3. If the drive direction of the connecting structures 7 is opposite, the directions of movement of the residual transverse movements Q can be opposite.

[0043] The Fig. 3a and Fig. 3b show a microelectromechanical device 1 for generating a fluid pressure according to a second embodiment. In its basic design and functional principle, the displacer structure 2 shown is comparable to the displacer structure 2 of the device 1 according to the first embodiment. The displacer structure 2 according to the Fig. 3a and Fig. 3b, however, has a first connecting structure group 11a and a second connecting structure group 11b, wherein the first connecting structure group 11a is connected to first slats 3a and the second connecting structure group 11b is connected to a second slat 3b. The first connecting structure group 11a can be driven in the opposite direction to the second connecting structure group 11b, so that the connecting structure movements A of the connecting structures 7 of the connecting structure group 11a, 11b can take place in opposite directions. This allows an opposite deflection movement L of the first slats 3a and the second slat 3b to be enabled. Viewed from top to bottom, Fig. 3a, the connecting elements 10 of the connecting structure groups 11a, 11b are each alternately connected to the deflection element 9 at a position of approximately ¼ and ¾ of the distance between the first slats 3a and the second slat 3b to a further second slat (not shown in detail). This results in a slight, rectified residual transverse movement Q of the drive elements 8, which can be compensated by the drive device 12. Fig. 3b, the connecting elements 10 are arranged opposite one another, so that an opposing residual transverse movement Q is present in the drive elements 8 of each connecting structure group 11a, 11b, so that they can already at least partially compensate for each other. The connecting structure groups 11a, 11b are configured such that the connecting structures 7 of the first connecting structure group 11a are arranged between the connecting structures 7 of the second connecting structure group 11b.

[0044] The Fig. 4a and Fig. 4b show a microelectromechanical device 1 for generating fluid pressure according to a third embodiment. In its basic design and functional principle, the displacer structure 2 shown is comparable to the displacer structure 2 of the device 1 according to the second embodiment. However, it is shown here that the connecting structures 7 of the first connecting structure group 11a and the connecting structures 7 of the second connecting structure group 11b can be arranged alternately one after the other. This allows the coupling points 6 of the deflection elements 9 on the first lamellae 3a and the second lamellae 3b to be placed at different distances apart in order to achieve different leverage effects and stiffnesses of the lamellae 3a, 3b.

[0045] The Fig. 5a and Fig. 5b show a microelectromechanical device 1 for generating a fluid pressure according to a fourth embodiment in two variants. The illustrated displacement structure 2 of the device 1 has a single connecting structure 7 with a drive element 8 and a deflection element 9, which are connected to one another via a connecting element 10 whose flexural rigidity is lower than the flexural rigidity of the drive element 8. In other words, the connecting element 10 is designed to be flexible. The flexible connecting element 10 is elastically deformable in an arc shape, so that a rotation V of the lamella 3 can be transmitted to the connecting element 10 via the deflection element 9. As a result, stiffening of the lamella 3 can be further reduced or avoided. The connection of the flexible connecting element 10 to the deflection element 9 can, for example, be approximately centrally between the lamellae 3 ( Fig. 5a) or near a coupling point 6 ( Fig. 5b). The deflection element 9 is elastically deformable in an arcuate manner, as shown. The connecting element 10 is connected to an arcuate section 25 of the deflection element 9. The arcuate section 25 is a region of arcuate deformation of the deflection element 9, to which a tangent T, as shown in the Fig. 5a and Fig. 5b, runs essentially at an angle to the drive element 8. As a result, the flexible connecting element 10 is connected to the drive element 8 with little torsion, since the selected connection point of the connecting element 10 causes the rotation V of the connecting element 10 in a deflected state of the slat 3 to approximately correspond to the rotation V of the deflection element 9 at the connection point. As a result, at least partial compensation of the rotation V up to the connection point of the connecting element 10 to the drive element 8 can be achieved. The connecting element 10 has a curved region 26 and a neutral region 27 adjoining the curved region 26. The connecting element 10 is connected to the drive element 8 via the neutral region 27. This also reduces or prevents the transmission of a rotation V to the drive element 8.

[0046] Fig. 6 shows a microelectromechanical device 1 for generating fluid pressure according to a fifth embodiment. In this embodiment, the deflection element 9 of the connecting structure 7 is not designed as a continuous deflection element 9 connected to the drive element 8 by means of connecting elements 10, but rather the drive element 8 has a separate flexible deflection element 9 for each lamella 3, which is directly connected to the drive element 8. This makes it possible to provide a particularly compact drive solution with a simple displacement structure 2. The deflection elements 9 have a sufficiently selected length or a sufficient distance from the coupling point 6 to the drive element 8 in order to compensate for a rotation V transmitted from the deflected lamella 3 to the deflection element 9 up to the connection point to the drive element 8.

[0047] The Fig. 7a and Fig. 7b show a microelectromechanical device 1 for generating a fluid pressure according to a sixth embodiment. In its basic design and functional principle, the displacer structure 2 shown is comparable to the displacer structure 2 of the device 1 according to the second embodiment, but instead of connecting structure groups 11a, 11b, individual connecting structures 7 that can be driven in opposite directions are implemented. The drive device 12 of the device 1 according to Fig. 7a and Fig. 7b is configured to convert a residual transverse movement Q transmitted from the drive elements 8 to the drive device 12 into a drive force acting on the drive elements 8. The direction of the force coincides with the direction of the residual transverse movement Q. This can generate a lever effect that transforms small strokes with large forces in the drive elements 8 into large strokes on the slats 3. Fig. Figure 7a shows a device 1 with a driving force between the connecting structures 7 without a stator, while Fig. 7b shows a device 1 with a driving force between the connecting structures 7 and a stator 16.

[0048] Fig. 8 shows a schematic top view of a microelectromechanical device 1 with a displacer structure 2 according to a seventh embodiment with geometric references. Thus, examples of lengths, widths, distances, and flexural rigidities shown in the figure are given below in order to illustrate the dimensions of the microelectromechanical device 1 using an exemplary embodiment and to relate them to one another. In its basic design and functional principle, the displacer structure 2 shown is comparable to the displacer structure 2 of the device 1 according to the first embodiment, although for reasons of clarity, only one connecting structure 7 is shown. The deflection element 9 has a first flexural rigidity E1I1, which is composed of the product of the elastic modulus E1 and the area moment of inertia I1 of the deflection element 9.The drive element 8 has a second flexural rigidity E2I2, which is composed of the product of the elastic modulus E2 and the area moment of inertia I2 of the drive element 8. Due to the geometric design of the deflection element 9 and the drive element 8, illustrated here as a narrow deflection element 9 and a wide drive element 8, the second flexural rigidity E2I2 of the drive element 8 is higher than the first flexural rigidity E1I1 of the deflection element 9. As a result, the deflection element 9 is elastically deformable, in contrast to the drive element 8. The elastic modulus E1 or E2 is to be understood as the effective elastic modulus, since the components of the displacement structure 2 of the device 1 can be made of anisotropic silicon and thus local elastic modulus fluctuations can occur.Suitable or favorable ranges of values ​​for the effective elastic modulus E1 or E2 can be, for example, between 1 GPa and 400 GPa, in particular between 120 GPa and 200 GPa. As shown schematically in . Fig. 8, the width b1 of the deflection element 9 can be smaller than the width b2 of the drive element 8. The deflection element 9 can, for example, have a width b1 between 0.5 and 100 µm, in particular between 1 and 50 µm. The drive element 8 can, for example, have a width b2 between 0.5 and 1500 µm, in particular between 50 and 500 µm. The drive element 8 and the deflection element 9 are connected to one another via connecting elements 10. The connecting element 10 can, for example, have a width b3 between 0.5 and 100 µm, in particular between 1 and 30 µm. The connecting element 10 can, for example, have a length l3 between 0.5 and 500 µm, in particular between 6 and 100 µm. The lamella 3 can, for example, have a width b4 between 0.5 and 100 µm, in particular between 1 and 30 µm. The lamella 3 can, for example, have a length l4 between 100 and 10,000 µm, in particular between 1,000 and 5,000 µm.A distance d1 between two connecting elements 10 can be, for example, between 5 and 4500 µm, in particular between 10 and 200 µm. A distance d0 between a coupling point 6 and the nearest connecting element 10 can be, for example, between 5 and 4500 µm, in particular ¼ of the distance d1 between two connecting elements 10. A distance d2 between two coupling points 6 can be, for example, between 5 and 4500 µm, in particular between 10 and 200 µm. A distance d3 between two slats 3 can be, for example, between 5 and 4500 µm, in particular between 10 and 200 µm. According to one embodiment, the distances d1, d2 and d3 can be substantially equal. A distance d4 between a slat end 5 of a slat 3 and a coupling point 6 on the same slat 3 can, for example, be between 0.01·(I4 / 2) - 0.99·(I4 / 2).

[0049] The Fig. 9a to 9d show a schematic top view and cross-sectional views of the microelectromechanical device 1 with a displacer structure 2 according to the first embodiment in a non-deflected state of the lamellae 3. Fig. 9a shows a top view, Fig. 9b a side cross-sectional view along section line AA, Fig. 9c a sectioned front view along the section line BB and Fig. 9d an alternative embodiment to the embodiment in Fig. 9c. The Fig. 9a can be analogous to Fig. 2a, where the connecting structures 7 are not driven, the slats 3 are not deflected and the deflection elements 9 are not elastically deformed. Fig. 9b, the left part of the image shows the connecting structure level with the drive element 8, followed by the coupling point level with the coupling point 6 and the right part of the image shows the slat level with the slat 3, with the support structure 18 visible in the background. Fig. 9c shows the spanned slat plane of the slat 3, wherein the coupling points 6 are shown at the slat edge as the outer boundary of the slat plane between the holding structures 18, via which the slat 3 is connected to the deflection elements 9, which in turn are connected to the drive elements 8. While in Fig. 9c shows an example of a connecting structure level above the lamella level, which in other embodiments can also be positioned below the lamella level, according to Fig. 9d, a connecting structure level with an analogous structure can also be provided above and below the slat level. A width b5 and a thickness b6 of the Fig. 9a can be, for example, between 0.5 and 100 µm, wherein the width b5 can be in particular half of a width b4 of the lamella 3 and wherein the thickness b6 can be in particular half of the width b1 of the deflection element 9. The in Fig. The height h1 of the drive element 8 and / or the deflection element 9 indicated in FIG. 9c can be, for example, between 0.5 and 600 µm, in particular between 5 and 60 µm. A height h2 of the coupling point 6 can be between 0.01 µm and 20 µm, in particular between 0.1 and 3 µm. A height h3 of the slat 3 can be, for example, between 1 and 2000 µm, in particular between 50 and 800 µm.

[0050] In the Fig. 10a and Fig. 10b shows schematic plan views of a microelectromechanical device 1 with a displacer structure 2 according to an eighth embodiment. In Fig. 10a the slats 3 are in their initial position, in Fig. 10b in its deflected state. In its basic design and functional principle, the displacer structure 2 shown is comparable to the displacer structure 2 of the device 1 according to the first embodiment. The support structure 18 is shown here as a circumferential frame with chamber partition walls 24, which separate a separate fluid chamber 23 for each lamella 3 shown. Lid openings 19 and bottom openings 20 are introduced into the fluid chambers 23 to allow the entry and exit of fluid flows into and from the fluid chambers 23. This is shown in Fig. 10b is sketched using illustrated fluid outlets 21 through the cover openings 19 and fluid inlets 22 through the bottom openings 20 according to the illustrated connection structure movement A and the deflection of the slats 3.

[0051] The Fig. 11a and Fig. 11b show schematic plan views of a microelectromechanical device 1 with a displacement structure 2 according to a ninth embodiment in two variants. The lamellae 3 are shown in a non-deflected state. In its basic design and functional principle, the displacement structure 2 shown is comparable to the displacement structure 2 of the device 1 according to the first embodiment. However, in this embodiment, the connecting elements 10 partially penetrate into a recess 28 in the drive elements 8. This allows for a compact embodiment of the connecting structures 7 to be provided. Fig. Figure 11b shows that two drive elements 8 can also have a common deflection element 9 and at least one common connecting element 10. This allows for a stable and reliable drive of the deflection element 9 in a compact design.

[0052] The Fig. 12a and Fig. 12b show schematic plan views of a microelectromechanical device 1 with a displacement structure 2 according to a tenth embodiment in two variants. The lamellae 3 are shown in a non-deflected state. In its basic design and functional principle, the displacement structure 2 shown is comparable to the displacement structure 2 of the device 1 according to the ninth embodiment. However, the connecting structures 7 previously shown with two separate drive elements 8 are designed such that a common drive element 8 is present for two deflection elements 9 connected to the drive element 8. This also allows a stable and secure drive of the deflection element 9 to be achieved in a compact embodiment. Fig. 12b shows such a common drive element 8 in addition to two outer drive elements 8, wherein the common drive element 8 and each outer drive element 8 enclose a common deflection element 9 and are connected via common connecting elements 10.

[0053] Fig.13 schematically shows a microelectromechanical loudspeaker 13 with a device 1 according to the above-described features and a signal processing unit 15, which is connected to the device 1 by a signal connection 14 and is designed to apply and process signals from the microelectromechanical device 1. The displacement structure 2 of the device 1 is configured to generate sound pressure as fluid pressure. The elastic deflection element 9 of the connecting structures 7 of the device 1 of the loudspeaker 13 prevents stiffening of the lamella 3. The microelectromechanical loudspeaker 13 can be implemented, for example, as a system-on-chip. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 2021 / 0 297 787 A1

[0002] WO 2021 / 144400 A1

[0003] WO 2021 / 223886 A1

[0004] DE 10 2019 203 914 B3

[0005] US 2012 / 0 018 244 A1

[0006] GB 2 554 470 A

[0007]

Claims

[1] Microelectromechanical device (1) for generating a fluid pressure with a displacement structure (2), wherein the displacement structure (2) has a movable lamella (3, 3a, 3b) which can be deflected to generate the fluid pressure by means of a drivable connecting structure (7) acting on the lamella (3, 3a, 3b), and wherein the connecting structure (7) has a drive element (8) and a deflection element (9) connecting the lamella (3, 3a, 3b) to the drive element (8), wherein the deflection element (9) has a lower flexural rigidity (E1I1) than the drive element (8) and is elastically deformable when the lamella (3, 3a, 3b) is deflected. [2] Device (1) according to claim 1, wherein the flexural rigidity (E2I2) of the drive element (8) is at least five times the flexural rigidity (E1I1) of the deflection element (9). [3] Device (1) according to claim 1 or 2, wherein the drive element (8) is connected to the deflection element (9) by means of a connecting element (10). [4] Device (1) according to claim 3, wherein the connecting element (10) has a higher flexural rigidity than the deflection element (9). [5] Device (1) according to claim 4, wherein the deflection element (9) is elastically deformable in an arcuate manner and wherein the connecting element (10) is connected to a neutral section (17) of the deflection element (9), wherein the neutral section (17) is a region of an arcuate deformation of the deflection element (9) at which a tangent (T) runs substantially parallel to the drive element (8). [6] Device (1) according to claim 3, wherein the connecting element (10) has a lower flexural rigidity than the drive element (8). [7] Device (1) according to claim 6, wherein the deflection element (9) is elastically deformable in an arcuate manner and wherein the connecting element (10) is connected to an arcuate section (25) of the deflection element (9), wherein the arcuate section (25) is a region of an arcuate deformation of the deflection element (9) at which a tangent (T) runs substantially at an angle to the drive element (8). [8] Device (1) according to claim 7, wherein the connecting element (10) has an arc region (26) and a neutral region (27) adjoining the arc region (26) during elastic deformation, and wherein the connecting element (10) is connected to the drive element (8) via the neutral region (27). [9] Device (1) according to one of the preceding claims, wherein the device (1) comprises a connecting structure group (11, 11a, 11b) with connecting structures (7) arranged parallel to one another, which have a drive element (8) and each have a deflection element (9) connecting the slat (3, 3a, 3b) to the drive element (8). [10] Device (1) according to one of the preceding claims, wherein the device (1) comprises a first lamella (3a), a second lamella (3b) and two connecting structure groups (11a, 11b) with connecting structures (7) arranged parallel to one another, wherein a first connecting structure group (11a) is connected to the first lamella (3a) and a second connecting structure group (11b) is connected to the second lamella (3b). [11] Device (1) according to claim 10, wherein the connecting structures (7) of the first connecting structure group (11a) are arranged between the connecting structures (7) of the second connecting structure group (11b). [12] Device (1) according to claim 10, wherein the connecting structures (7) of the first connecting structure group (11a) and the connecting structures (7) of the second connecting structure group (11b) are arranged alternately one after the other. [13] Device (1) according to one of the preceding claims, wherein the device (1) comprises a drive device (12) which is designed to convert a residual transverse movement (Q) transmitted from the drive element (8) to the drive device (12) into a drive force acting on the drive element (8). [14] Device (1) according to one of the preceding claims, wherein - the connecting element (10) has a higher bending stiffness than the deflection element (9), - the connecting element (10) is connected to a neutral section (17) of the deflection element (9), wherein the neutral section (17) is a region of an arcuate deformation of the deflection element (9), at which a tangent (T) runs substantially parallel to the drive element (8), - the device (1) has a connecting structure group (11, 11a, 11b) with connecting structures (7) arranged parallel to one another, which have a drive element (8) and a respective deflection element (9) connecting the slat (3, 3a, 3b) to the drive element (8), and - the device (1) has a first lamella (3a), a second lamella (3b) and two connecting structure groups (11a, 11b) with connecting structures (7) arranged parallel to one another, wherein a first connecting structure group (11a) is connected to the first lamella (3a) and a second connecting structure group (11b) is connected to the second lamella (3b). [15] Microelectromechanical loudspeaker (13) comprising a microelectromechanical device (1) according to one of claims 1 to 14, wherein the displacer structure (2) is configured to generate sound pressure as fluid pressure, and a signal processing unit (15) for applying and processing signals of the microelectromechanical device (1).

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