Fluid pump device comprising a first membrane and a second membrane

Abstract

The invention relates to a fluid pump device (100) comprising: at least one chip (101), each chip having a chip frame (102) and a fluid flow opening (130); and at least one first membrane (104) and at least one second membrane (106). The at least one first membrane (104) and the at least one second membrane (106) each comprise a number of suspension points (110) and an excitation element (108). The at least one first membrane (104) and the at least one second membrane (106) are arranged one above the other, offset relative to one another, and spaced apart from one another, the at least one first membrane (104) being arranged optionally either transversely or longitudinally over the chip frame (102). A fluid volume (304) can be enclosed between the membranes (104, 106) and can be displaced upon excitation of the membranes (104, 106).

Description

[0001] R.414121

[0002] - 1 -

[0003] Description

[0004] title

[0005] Fluid pumping device with a first membrane and a second membrane

[0006] Technical field

[0007] The invention relates to a fluid pump device for generating sound waves in an audible wave spectrum, comprising at least one chip with a chip frame and a fluid flow opening, and at least one first diaphragm and at least one second diaphragm. The invention further relates to the use of a fluid pump device.

[0008] State of the art

[0009] MEMS-based loudspeakers, such as micro loudspeakers, have considerable market potential due to improved sound quality and potentially lower energy consumption. However, many concepts struggle to achieve sufficiently powerful acoustic performance. One factor in this regard is that increasing the sound pressure level (SPL) requires an increase in the displaced volume. This volume increase can be achieved, for example, by enlarging both the excursion range of a diaphragm and by increasing chip dimensions. From an economic perspective, however, it is important to consider that chip size is a significant factor, especially with regard to SPL. Therefore, various concepts have been developed to achieve high sound power levels with a small chip size.

[0010] Systems based on the use of louvers, which are deflected or shifted relative to each other or to fixed walls, are already known. Various concepts and designs have been presented in this context, including WO 2021 / 144400, WO2021223886A1, DE 10 2019 203 914, and the MEMS loudspeaker. (See Kaiser et al. (2019) Microsystems & R.414121)

[0011] - 2 -

[0012] Nanoengineering 5:43 points out that such systems often deliver an insufficiently high SPL. In particular, covering the entire audible frequency range (20-20 kHz) presents a challenge. Ultrasonic modulation concepts offer a way to achieve sufficiently high SPLs, especially in the low frequency range. US2022224999A1 serves as an exemplary reference in this context. These concepts are based on a pump-like structure and one or more valve devices, through the controlled build-up and release of pressure to modulate a target frequency.

[0013] German patent application DE 10 2017 214630 A1 describes a microelectromechanical system (MEMS) comprising a substrate and a membrane suspended from it, which is movable between a first stable displacement state and a second stable displacement state. This MEMS includes an actuator designed to move the membrane from one of the two stable displacement states. Furthermore, the MEMS is equipped with a sensor capable of detecting movement of the membrane induced by the actuator and outputting a sensor signal containing displacement information based on the movement. Additionally, an evaluation device is provided that analyzes the displacement information to obtain information about the state of the membrane.

[0014] WO 2017055384 A1 discloses a MEMS printed circuit board assembly of a sound transducer arrangement for generating and / or detecting sound waves in the audible wavelength spectrum, comprising a printed circuit board and a multilayer piezoelectric structure. The printed circuit board has a dedicated diaphragm that can be set into vibration by means of a piezoelectric structure and / or by means of which vibrations of the diaphragm can be detected. The printed circuit board is designed to be flexible, and the multilayer piezoelectric structure is embedded in the printed circuit board. Furthermore, the disclosure relates to a transducer arrangement for generating and / or detecting sound waves in the audible wavelength spectrum, comprising a diaphragm, a recess, and a MEMS printed circuit board assembly, which includes a printed circuit board and a multilayer piezoelectric structure. The transducer arrangement enables the generation and / or detection of sound waves.414121.

[0015] - 3 - len through the piezoelectric multilayer structure, whereby the membrane can be set into vibration and / or vibrations of the membrane can be detected.

[0016] Disclosure of the invention

[0017] According to the invention, a fluid pumping device is proposed comprising at least one chip with a chip frame, a fluid flow opening, and at least one first membrane and at least one second membrane. The at least one first membrane and the at least one second membrane each have a number of suspension points and an excitation element. The at least one first membrane and the at least one second membrane are arranged one above the other, offset from each other, and spaced apart. Furthermore, the at least one first membrane is optionally arranged either transversely or longitudinally over the chip frame, and a fluid volume can be enclosed between the membranes, which is displaceable when the membranes are excited.

[0018] The fluid pump device presented according to the invention is based on a pumping mechanism consisting of at least two opposing diaphragms. This mechanism advantageously generates sound waves in an audible wave spectrum. The at least one first and at least one second diaphragm are spatially offset from one another and are operated out of phase. The spatial distance between the diaphragms is designed such that a volume can advantageously be enclosed between them. By means of a corresponding vibration of the diaphragms, an enclosed or surrounded volume is moved from a first opening of the diaphragm pair to the second opening, or vice versa, thereby creating a pumping effect. A further diaphragm pair, which can be operated in the opposite direction, generates a pumping effect in the reverse direction.This paired arrangement allows for both pumping fluid volume into and out of a chamber. Pumping pulses of the membranes in the ultrasonic range enable the fluid pumping device proposed according to the invention to be used for modulating sound waves in the audible range. Furthermore, the fluid pumping device is scalable, for example, over many orders of magnitude, thereby making effective sound pressure levels (SPL) achievable. R.414121.

[0019] - 4 -

[0020] According to the invention, a fluid pumping device is a system for generating sound waves by manipulating a fluid, for example, air. The fluid pumping device comprises, for example, a pump, in particular a diaphragm base, which moves the fluid through a conduit, for example, between two superimposed diaphragms, and a mechanism that converts the movement of the fluid into vibrations or oscillations to generate sound waves. These sound waves are used, among other things, in MEMS systems and in various fields such as ultrasound imaging, humidification, loudspeaker or microphone technology, and other acoustic applications.

[0021] A substrate forms the basis of, for example, the fluid pump system and the MEMS module, enabling the arrangement and integration of microscopic mechanical and electronic components such as the fluid pump system's membranes. It can be made of a semiconductor material such as silicon and provides a solid platform for the system's structural stability. For example, the substrate can be in the form of a silicon wafer on which the MEMS structures are precisely fabricated by lithography and etching.

[0022] A diaphragm, for example, represents a flexible structure within the fluid pump device, which serves to generate sound waves in the audible spectrum. The diaphragm can be made of materials such as silicon nitride, polyimide, or other flexible polymers. Another embodiment includes, for example, a thin layer of silicon nitride that is set into vibration by electrostatic excitation or piezoelectric effects to generate acoustic waves. The excitations cause the diaphragm to vibrate, ultimately generating acoustic waves. The vibrations can be precisely controlled and modulated to achieve acoustic properties such as frequency, amplitude, and phase of the generated sound waves. When not excited, the diaphragm is in a resting state, which encompasses a stable, neutral position without vibration or displacement.The resting state represents the initial state of at least one membrane before excitation, namely actuation, occurs to generate vibrations. Through the influence of external stimuli, for example electrostatic excitation, the membrane R.414121.

[0023] - 5 - capable of being deflected from its resting state. This first deflection state results in a defined movement of the diaphragm in one direction. The controlled and variable deflection allows for a changeable amplitude and direction of the vibration. Through further external actuation or adjustments of one or more parameters, the vibrating diaphragm can be moved into a second deflection state. In the second deflection state, the diaphragm achieves a deflection in the opposite direction compared to the first deflection state. An increase or change in the movement of the diaphragm is possible, for example, to generate a wider range of sound wave frequencies and amplitudes. The deflection states of the diaphragm enable the fluid pump system to generate precisely controlled vibrations, which are used to generate sound waves in the audible range.Depending on the specific application requirements and operating conditions, the deflection of the diaphragms can be varied to ensure optimal system performance. In the solution according to the invention, a vibration of the respective diaphragms of the fluid pump device is generated at a resonant frequency. The resonant frequency at which the diaphragms are operated results in advantageously low energy consumption. Depending on the specific application and its characteristics, a vertical or horizontal diaphragm configuration is possible. This allows for flexible adaptation of chip size and diaphragm properties, such as stiffness, spacing, or dimensions, to the specific requirements.

[0024] A proposed method for the layer-by-layer construction of at least one first membrane and at least one second membrane allows for precise manufacturing. This approach enables highly accurate control and adjustment of the layers. Compared to traditional manufacturing methods, which often require larger tolerances, the layer-by-layer approach allows for finer adjustments and higher precision. This is particularly advantageous for applications where minimal deviations from the target dimensions are critical.

[0025] In an advantageous further development of the fluid pump device proposed according to the invention, the fluid pump device is designed to generate sound waves in the audible range and the at least one first diaphragm and R.414121

[0026] - 6 - at least one second membrane is operated in the ultrasound range above 20 kHz.

[0027] In an advantageous further development of the fluid pump device proposed according to the invention, the excitation element is designed as a piezoelectric element.

[0028] The fluid pumping device according to the invention can, for example, be constructed from at least one pair of membranes, namely a first membrane and a second membrane, which are arranged offset one above the other. This arrangement enables, among other things, improved functionality of the fluid pumping device, since the membranes interact closely with each other. In an exemplary alternative embodiment, the fluid pumping device can be constructed from several pairs of membranes arranged side by side and offset from each other. These pairs of membranes are arranged side by side, with each pair being constructed similarly to the first pair. This modular design of the membranes allows the fluid pumping device to be flexibly adapted to different requirements.For example, additional membrane pairs can be added or removed as needed to achieve a desired performance, such as pumping power or pumping effect.

[0029] In an advantageous further development of the fluid pump device proposed according to the invention, the excitation element is designed as an electrostatic actuator.

[0030] In a further advantageous embodiment of the fluid pump device proposed according to the invention, at least one suspension point is designed as a torsion spring.

[0031] In a further advantageous embodiment of the fluid pump device proposed according to the invention, the membranes are arranged longitudinally above the chip frame. The membranes are arranged above the chip frame such that the distance between the chip frame and the at least one first membrane is less than 5 pm, preferably less than 3 pm, and particularly preferably less than 2 pm. R.414121

[0032] - 7 -

[0033] In a further advantageous embodiment of the fluid pump device proposed according to the invention, the at least one first membrane and the at least one second membrane are arranged one above the other, offset from each other and spaced apart from each other, such that the suspension points of the respective membranes are arranged spatially offset from each other.

[0034] The fluid pumping device according to the invention allows for several design freedoms. For example, the volume—namely, the pump volume, i.e., the enclosed volume or fluid volume displaced by excitation of at least one first and at least one second diaphragm per pumping cycle—can be changed as required. For example, the pump volume can be increased by spatially extending the diaphragms in a principal direction of expansion. Furthermore, the resonance frequency of the diaphragms can be adjusted via their stiffness, both by selecting and / or combining materials and by varying the distance between the individual suspension points.

[0035] In a further advantageous embodiment of the fluid pump device proposed according to the invention, the suspension points are arranged such that a midpoint between two adjacent suspension points of at least one first membrane is located directly below a suspension point of at least one second membrane.

[0036] In a further advantageous embodiment of the fluid pump device proposed according to the invention, the at least one first membrane and the at least one second membrane are arranged one above the other, offset from each other and spaced apart from each other, such that the arrangement of the membranes has a first opening and a second opening.

[0037] Through suitable vibration, for example of two membranes, an enclosed volume is moved from the first opening of the membrane pair to the second opening or vice versa, thereby creating a beneficial pumping effect. The two exemplary membrane pairs, the first and the second membrane, perform vibrations, for example with different amplitudes. By controlling the membranes, for example by a piezoelectric element or also by electrostatic control, an amplitude can be di- R.414121

[0038] - 8 - can be controlled via a voltage. If the membranes are controlled with different amplitudes, the spatial distance at the point of closest approach of the two membranes to each other changes. These points of closest approach of the two membranes enclose the volume, namely the pump volume, and thus enable a directed pumping action. To achieve maximum pumping performance, the spatial distance can be kept as small as possible to prevent backflow of the enclosed volume against the pumping direction. For example, the fluid pumping device according to the invention can be designed as an arrangement of a plurality of nested membrane pairs, wherein the enclosed volume, which is pumped from left to right, can be reduced as required by selectively opening at least one opening of these membrane pairs.This allows for smaller pump pulses and therefore a lower pressure increase, for example in an ear, per pump pulse. In this way, a desired audio signal can be modulated more precisely, with the gradient of the pressure increase or decrease being adapted to the shape of the audio signal being modulated.

[0039] In a further advantageous embodiment of the fluid pump device proposed according to the invention, the at least one first membrane and the at least one second membrane are arranged one above the other in such a way that the membranes are not in contact with each other.

[0040] Furthermore, the invention relates to the use of the fluid pump device in a microelectromechanical system, in particular in pumps, microphones, microfluidics, and for microelectronic loudspeakers based on the microelectromechanical system. A micromechanical system (MEMS) is understood to be a mechanical system whose components and structures are scaled to the micrometer scale (millionths of a meter).

[0041] Advantages of the invention

[0042] In the solution according to the invention, excitation of the at least one first membrane and the at least one second membrane results in a movement of the space between the at least one first membrane and the at least R.414121

[0043] - 9 - a second membrane enclosed volume achieves an efficient and directed pumping direction, thereby achieving an advantageous modulation of the sound waves per pump stroke, which enables precise modulation of the audio signal.

[0044] Furthermore, the solution according to the invention enables versatile functionality of the fluid pumping device through a paired arrangement of at least one first and a second membrane. Moreover, the fluid pumping device according to the invention can both pump and remove a volume of fluid by exciting the membranes with pulses in the ultrasonic range. The proposed solution enables modulation of sound waves in the audible range, which makes the fluid pumping device particularly advantageous for applications requiring precise acoustic control.

[0045] Among the outstanding features of the fluid pumping device proposed according to the invention is its scalability in many dimensions. This flexibility allows for the generation of high sound pressure levels (SPL), in contrast to other solutions, while simultaneously enabling the physical properties of the diaphragms and chips, such as stiffness, spacing, and dimensions, to be adapted to specific requirements. This allows for efficient adaptation of the fluid pumping device, and in particular of a system that uses this fluid pumping device, to different application scenarios.

[0046] Furthermore, the invention is characterized by low energy consumption at the membranes' resonance frequency. These properties not only contribute to economical operation but also enable precise and efficient performance of the fluid pumping device. This combination of performance and energy efficiency increases the attractiveness of the fluid pumping device for applications where both volume control, such as fluid volume, and the generation and modulation of sound waves are of central importance.

[0047] The ability to mount the fluid pumping device both vertically and horizontally also offers an advantageous adaptability. This is particularly relevant to R.414121.

[0048] - 10 - This is particularly important for integration into different devices and environments, as space requirements and specific design needs vary. This flexibility in design allows for versatile use of the fluid pump device. For example, very small or particularly compact and efficient loudspeakers can be developed for in-ear applications, which, due to their high efficiency, have a long battery life. Alternatively, they can be used in consumer electronics to generate high-quality audio output, especially for noise reduction applications. To ensure effective noise reduction, the loudspeaker must have particularly high sound quality, especially in the mid and lower frequency ranges, high dynamic range, and maximum volume.

[0049] Brief description of the drawings

[0050] Embodiments of the invention are explained in more detail with reference to the drawings and the following description.

[0051] They show:

[0052] Figure 1 shows a schematic representation of a fluid pumping device,

[0053] Figure 2 is a graphical representation of the movement of a first and a second membrane over time.

[0054] Figure 3 shows a graphical representation of a pumping mechanism in individual phases of the cycle.

[0055] Figure 4 shows a graphical representation of the first and second membranes with different amplitudes.

[0056] Figure 5.1 shows a graphical representation of a basic principle of ultrasonic modulation for generating audible audio signals with a pump signal and R.414121

[0057] - 11 -

[0058] Figure 5.2 shows a graphical representation of a basic principle of ultrasound modulation for generating audible audio signals using a pump signal with an increased frequency.

[0059] Embodiments of the invention

[0060] In the following description of embodiments of the invention, identical or similar elements are designated by the same reference numerals, and repeated descriptions of these elements are omitted in individual cases. The figures represent the subject matter of the invention only schematically.

[0061] Figure 1 shows a schematic representation of an exemplary fluid pump device 100, with which sound waves in an audible wave spectrum are generated. Figure 1.1 also shows a chip 101 with a chip frame 102, wherein the chip 101 has a fluid flow opening 130. In the illustrated embodiment, a first diaphragm 104 and a second diaphragm 106 are arranged above the chip 101, spaced apart in the z-direction 122 and offset from each other, such that there is a first distance 126 between the first diaphragm 104 and the second diaphragm 106 and a second distance 128 between the first diaphragm 104 and the chip 101. The first distance 126 of the membranes 104, 106 in the z-direction 122 is chosen, for example, such that at maximum deflection of the two membranes 104, 106 no contact occurs between the membranes 104, 106.The second distance 128 between the first membrane 104 and the chip 101 or chip frame 102, which lies in the image plane (parallel to the x-direction 118), can, for example, preferably be <5 pm and particularly preferably <2 pm to avoid an acoustic leakage path in these areas. An offset of the first membrane 104 and the second membrane 106 in the x-direction 118 is shown in Figure 1. Furthermore, it can be seen from Figure 1 that, due to the offset, an arrangement of the first membrane 104 and the second membrane 106 has a first opening 111 and a second opening 113. Thus, the first opening 111 and the second opening 113 allow a first media flow 112 and a second media flow 114 between the membranes 104, 106 and out of the space between the membranes 104, 106. A media flow direction 116 depends, for example, on a phase in which the two membranes 104, 106 are operated. R.414121.

[0062] - 12 -

[0063] The fluid pumping device 100 is characterized, for example, by several design freedoms that make it possible to adapt the features of the invention. For example, the pump volume, namely the media flow 112, 114, which is moved per pumping cycle, can be changed as required. For example, the enclosed volume 136 can be increased by extending the membranes 104, 106 spatially in the y-direction 120. A resonance frequency of the membranes 104, 106 can be set, for example, by adjusting the stiffness of the membranes 104, 106, firstly by selecting a material (material combination), and secondly by adjusting the distance 134 in the x-direction 118 between the individual suspension points 110.

[0064] The first membrane 104 and the second membrane 106 each have an excitation element 108. For example, the respective excitation element 108 can be configured as a piezoelectric element 109.1 or as an electrostatic actuator 109.2. Furthermore, the first and second membranes 104, 106 shown in Figure 1 each have three suspension points 110, which can, for example, be configured as torsion springs 110.1. Alternatively, the number of suspension points 110 can differ from the exemplary embodiment depending on the specific requirements and / or the size of the membranes 104, 106. Furthermore, it can be seen from Figure 1 that the suspension points 110 of the respective first membrane 104 and the second membrane 106 are arranged one above the other in such a way that at least one of the suspension points 110 is arranged above or below a center point 124 between two suspension points 110 of the opposite membrane 104, 106.

[0065] In an embodiment not shown here, the concept of the fluid pump device 100, particularly with regard to the arrangement of the membranes 104, 106, can also be configured vertically. In this case, the membranes 104, 106 have a primary expansion direction in the x-direction 118 (same as the primary expansion direction as shown in Figure 1) and a secondary expansion direction in the z-direction 122 (in contrast to Figure 1, where the secondary expansion direction is in the y-direction 120), and a thickness of the membranes 104, 106 in the y-direction 120 (in contrast to Figure 1 in the z-direction 122). This embodiment allows for scaling of the membranes 104, 106 in the z-direction 122, thus eliminating the need for additional chip area, which in turn has a positive effect on the manufacturing cost. R.414121

[0066] - 13 -

[0067] Figure 2 schematically shows the movements of the two membranes 104 (first membrane) and 106 (second membrane) over time 202. Due to the suspension points 110, the two membranes 104, 106 perform standing wave movements 204. By means of a suitably chosen phase offset of the two membrane vibrations, a volume 136 can be enclosed or surrounded between the two membranes 104, 106, which in the case shown moves from left to right. This system, which can be implemented according to a fluid pump device 100, can be used to pump a fluid volume 304 at an ultrasonic frequency.

[0068] A pumping mechanism comprising the first membrane 104 and the second membrane 106 with a plurality of offset suspension points 110 is shown in Figure 3 in individual cycle phases, namely a first phase 300.1, a second phase 300.2, and a third phase 300.3. Furthermore, Figure 5 shows a fluid volume 304 which moves from left to right in a pumping direction 302 during the pumping cycle.

[0069] Figure 4 shows a first membrane 104 and a second membrane 106, which, for example, perform vibrations of different amplitudes. An amplitude can be controlled directly via a voltage, for example, by driving the membranes 104 and 106 through an excitation element 108, for example, by means of a piezoelectric element 109.1 or also via the electrostatic actuator 109.2. When the membranes 104, 106 are operated with different amplitudes, the spatial distance 402 of the nearest approach 403 of the two membranes 104, 106 changes. These points of nearest approach 403 of the two membranes 104, 106 enclose the fluid volume 304 and thus enable a directed pumping action in a pumping direction 302. For maximum pumping performance, the spatial distance 402 of the nearest approach 403 of, for example, the two membranes 104, 106 should be as small as possible to prevent backflow of the fluid volume 304 against the pumping direction 302.

[0070] Figures 5.1 and 5.2 each show a basic principle of ultrasonic modulation 500 of audible audio signals 506. In this process, a pumping signal 508 is generated at an ultrasonic frequency in a closed volume, for example, the ear canal. R.414121

[0071] - 14 -

[0072] Figure 5.1 shows a graph representing time 502 on the x-axis and pressure 504 on the y-axis. A pump signal 508 with a specific frequency is shown, which periodically increases and decreases the pressure 504 in the closed volume. This pump signal 508 is crucial for how precisely a desired audio signal 506 can be modulated.

[0073] Figure 5.2 shows a similar graph to Figure 5.1, representing time 502 on the x-axis and pressure 504 on the y-axis; however, the pump signal 508 oscillates here at a frequency three times higher than the signal in Figure 5.1. This means that the pressure 504 in the closed volume increases and decreases more rapidly, potentially leading to higher resolution or frequency modulation of the audio signal 506.

[0074] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, within the scope defined by the

[0075] Within the specified area, a multitude of variations are possible, which fall within the scope of professional practice.

Claims

R.414121 - 15 - Claims 1. Fluid pumping device (100) comprising at least one chip (101) with a chip frame (102) and a fluid flow opening (130), and at least one first membrane (104) and at least one second membrane (106), wherein the at least one first membrane (104) and the at least one second membrane (106) each have a number of suspension points (110) and each have an excitation element (108), wherein the at least one first membrane (104) and the at least one second membrane (106) are arranged one above the other, offset from each other and spaced apart from each other, wherein the at least one first membrane (104) is optionally arranged either transversely or longitudinally over the chip frame (102), wherein a fluid volume (304) can be enclosed between the membranes (104, 106), which can be displaced when the membranes (104, 106) are excited.

2. Fluid pump device (100) according to claim 1, wherein the fluid pump device (100) is designed to generate sound waves in the audible range and the at least one first diaphragm (104) and the at least one second diaphragm (106) are operated in the ultrasonic range above 20 kHz.

3. Fluid pump device (100) according to claim 1 or 2, wherein the excitation element (108) is designed as a piezo element (109.1).

4. Fluid pumping device (100) according to claim 1 or 2, wherein the excitation element (108) is designed as an electrostatic actuator (109.2).

5. Fluid pump device (100) according to one of the preceding claims, wherein at least one suspension point (110) is designed as a torsion spring (110.1). R.414121 - 16 - 6. Fluid pump device (100) according to one of the preceding claims, wherein the membranes (104, 106) are arranged longitudinally above the chip frame (102), wherein the membranes (104, 106) are arranged above the chip frame (102) such that the distance between the chip frame (102) and the at least one first membrane (104) is less than 5 pm, preferably less than 3 pm, particularly preferably less than 2 pm.

7. Fluid pump device (100) according to one of the preceding claims, wherein the at least one first membrane (104) and the at least one second membrane (106) are arranged one above the other, offset from each other and spaced apart from each other such that the suspension points (110) of the respective membranes (104, 106) are arranged spatially offset from each other.

8. Fluid pump device (100) according to claim 6, wherein the suspension points (110) are arranged such that a midpoint (124) between two adjacent suspension points (110) of the at least one first membrane (104) is arranged directly below a suspension point (110) of the at least one second membrane (106).

9. Fluid pump device (100) according to one of the preceding claims, wherein the at least one first diaphragm (104) and the at least one second diaphragm (106) are arranged one above the other, offset from each other and spaced apart from each other such that the arrangement of the diaphragms (104, 106) has a first opening (111) and a second opening (113).

10. Fluid pumping device (100) according to one of the preceding claims, wherein the at least one first diaphragm (104) and the at least one second diaphragm (106) are arranged one above the other in such a way that the diaphragms (104, 106) are not in contact with each other.

11. Use of the fluid pump device (100) according to one of the preceding claims in a microelectromechanical system, in particular in pumps, microphones and in microfluidics and for microelectronic loudspeakers based on the microelectromechanical system.

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