FLUID PUMP DEVICE COMPRISING AN ACTIVELY CONTROLLABLE VALVE STRUCTURE

Abstract

The invention relates to a fluid pump device (200) for generating sound waves in an audible range, comprising: - a channel structure (226) having at least two channels (228, 230), which are coupled and each have a volume (208, 210), wherein the at least two channels (228, 230) are separated by at least one inner channel wall (214.3), - one or more ultrasound generating elements (202), which are arranged either transversely or parallel to the channels (228, 230) and can be operated at a frequency in order to pump defined volumes of fluid between the respective volumes (208, 210) of the channels (228, 230) with a variable pumping direction, and - at least one valve structure (212), wherein the at least one valve structure (212) is actively controllable and is designed in such a way that at least one valve structure (212) can be operated both in a pumping state and in a suction state and has a vibration in resonance with the ultrasonic vibration of an ultrasonic source for generating an effective ultrasonic modulation, - and at least one excitation mechanism for exciting the one or more valve structures (212).

Description

[0001] R.415781

[0002] - 1 -

[0003] Description

[0004] title

[0005] Fluid pumping device with an actively controllable valve structure

[0006] Technical field

[0007] The invention relates to a fluid pump device for generating sound waves in an audible range, comprising a channel structure, at least one ultrasound generating element, at least one actively controllable valve structure, and at least one excitation mechanism. The invention further relates to the use of a fluid pump device.

[0008] State of the art

[0009] Microelectromechanical systems (MEMS) offer promising potential for the development of loudspeakers (pSpeakers). One of the key challenges in the development process is generating sufficiently high sound power. Increasing the sound power level (SPL) requires a larger displaced volume, which can be achieved either by increasing the excursion of a diaphragm or by increasing the dimensions of a chip. However, increasing chip dimensions leads to higher production costs (price per chip, PPC). To achieve increased sound power despite a small chip size, various concepts have been developed. These involve optimizing the diaphragm excursion within the chip's boundaries. However, existing concepts have limitations regarding the achievable sound power.

[0010] Various concepts and designs have been presented so far, for example WO 2021 / 144400, WO 2021 / 223886 A1, DE 10 2019 203 914, and the MEMS loudspeaker. In the publication “Microsystems & Nanoengineering” (2019) 5:43, the author points out that such systems often do not have an R.415781

[0011] - 2 - possess sufficiently high sound pressure levels (SPL). This applies particularly to systems intended to cover the entire audible frequency range (20 Hz–20 kHz). Sufficiently high sound pressure levels, especially in the low-frequency range, such as frequencies from 20 to 400 Hz, can be achieved using ultrasound modulation concepts, such as those described in US 2022 / 224999 A1. These concepts are based on a pump-like structure and one or more valve devices to modulate a target frequency from pump pulses. The quantified pump pulses at ultrasonic frequencies enable the generation of low-frequency waves, for example, in the audible range, with very high amplitudes.

[0012] In current systems, multiple valve structures are often used to control pressure build-up and pressure release. However, the use of multiple valve structures increases the system's complexity, significantly raising both manufacturing and maintenance costs. Furthermore, a higher number of components leads to a higher overall system price, limiting the economic viability of such systems in certain applications.

[0013] Disclosure of the invention

[0014] According to the invention, a fluid pump device for generating sound waves in an audible range is proposed.

[0015] The fluid pumping device comprises at least: a channel structure, wherein the channel structure has at least two coupled channels, each channel having a volume, each volume having a different dimension or the same dimension, wherein the at least two channels are separated by at least one inner channel wall; one or more ultrasonic generating elements, arranged either transversely or parallel to the channels and operable at a frequency to pump defined volumes of fluid between the respective volumes of the channels, wherein a pumping direction from one volume to the other volume is variable; and R.415781

[0016] - 3 - at least one valve structure, wherein the at least one valve structure is actively controllable and designed such that at least one valve structure can be operated in both a pumping and a suction state and has a vibration in resonance with the ultrasonic vibration of an ultrasonic source to generate effective ultrasonic modulation, and at least one excitation mechanism for exciting one or more valve structures.

[0017] A fluid pumping device according to the invention, which is based on an advantageous combination of one or more ultrasonic generating elements, conveys a fluid through at least one actively controllable valve structure across two volume regions with different flow resistances. In a channel structure with at least two channels, the at least one actively controllable valve structure generates a variable flow resistance of the fluid medium, such as air, depending on the flow direction. The active controllability of the valve structure ensures, on the one hand, the realization of a pumping state and, on the other hand, the realization of a suction state of the fluid pumping device, wherein the control is effected by at least one valve structure.

[0018] According to the invention, a fluid pumping device is a system for generating sound waves by manipulating a medium such as air. For example, a fluid pumping device can include a pump that moves the medium through a pipe or channel structure and a mechanism for converting the movement of the fluid into vibrations or oscillations to generate sound waves. These sound waves are used, for example, in micromechanical systems (MEMS) and in a variety of fields such as ultrasound imaging, humidification, loudspeaker or microphone technology, and other acoustic applications.

[0019] A channel structure, as defined in the invention, is a structure comprising a fluid pump device for generating sound waves through a medium, such as air. The channel structure is formed, for example, by pipes, conduits, or ducts. R.415781

[0020] - 4 - formed, which guide the fluid along a defined path. In a fluid pump device for generating sound waves, the channel structure fulfills a transport function by directing fluid from a pump to a mechanism that sets the fluid into vibration to generate sound waves. The channel structure according to the invention allows for targeted control and efficient transport of the fluid, thereby ensuring effective sound wave generation.

[0021] In the context of the fluid pump device according to the invention, an ultrasonic generating element is understood to be a component that serves to generate sound waves in the audible range. An example of the use of ultrasonic generating elements is their application in microelectromechanical systems, so-called MEMS loudspeakers. Such ultrasonic generating elements generate vibrations in the ultrasonic range, which are then transmitted through the medium, usually air, to produce sound. According to the invention, one or more ultrasonic generating elements can be arranged either transversely or parallel to the channels. A parallel arrangement of the ultrasonic generating elements results in a smaller surface area requirement, since a reduction in diaphragm area and an increase in the maximum achievable volume displacement per displacement of the ultrasonic generating element can be expected.Increasing the maximum achievable volume displacement per deflection of the ultrasound generating element is crucial for the maximum achievable sound pressure level (SPL). The parallel arrangement also allows for efficient use of the valve structure, as hardly any additional space is required.

[0022] Within the scope of the invention, a valve structure is understood to be a mechanical device that controls the flow of a medium (such as gas, liquid, vapor, or air) in a fluid pumping device. This is achieved by actively controlling the flow, which is either allowed, blocked, or regulated by the valve structure. A valve structure comprises, for example, a movable element, such as a valve stem or a disc. Controlling the movement of the movable element causes a change in the open and / or closed state of the valve structure. This implies an influence on the flow of the medium within the fluid pumping device. R.415781

[0023] - 5 - The valve structure according to the invention is designed such that active control of the at least one valve structure is ensured. This is achieved by at least one excitation mechanism, which ensures dynamic and / or static control of the movable element, for example in real time. The active control is based, for example, on predefined parameters such as pressure, temperature, or volume flow, thereby enabling precise adjustment of the position of the valve structure to changing operating conditions. This results in improved control accuracy, faster response times, and increased efficiency of the overall system. The valve structure according to the invention advantageously has a one-sided anchoring to a wall between the channels, with the anchoring preferably taking place on an inner channel wall.The other end of the valve structure is preferably free to move. An anchoring mechanism can be designed, for example, as a hinge or spring to facilitate free movement of the valve structure while maintaining the required stability. The deflection of the valve structure during active operation is crucial for its length parallel to the channels. Advantageously, this length is designed such that, in the deflected state of the valve structure, one of the two channels is closed as completely as possible. This ensures high efficiency of the valve structure. High efficiency refers to the maximum possible flow resistance generated by the valve structure for the channel to be closed.

[0024] An excitation mechanism according to the invention is a device that serves for the targeted control of at least one valve structure in a fluid pumping device and triggers mechanical movements or functional changes of at least one valve structure. The excitation mechanism is designed to control at least one valve structure. Control is achieved using one or more control principles, for example, electrostatic control, electromagnetic control, or pneumatic control. In electrostatic control, an electric field is generated, which enables precise and efficient movement of the valve structure. In a fluid pumping device according to the invention with multiple valve structures, the excitation mechanism is designed, for example, such that the valve structures can be controlled either dependently or independently of one another. R.415781

[0025] - 6 - are. In dependent control mode, a coordinated active control of valve structure positions takes place, while in independent control mode each valve structure can be actively controlled separately, thus ensuring individual operating states of the valve structures.

[0026] In an advantageous further development of the fluid pump device proposed according to the invention, the ultrasound generating element is a first vibrating membrane.

[0027] In an advantageous embodiment of the fluid pumping device proposed according to the invention, the at least one valve structure has a natural frequency. This natural frequency corresponds to an excitation frequency. A natural frequency of the valve structure is the frequency at which an excited valve structure tends to oscillate at a natural frequency without external damping influences. The natural frequency depends on the physical properties of the valve structure, in particular its mass, stiffness, and geometry.

[0028] In a further advantageous embodiment of the fluid pumping device proposed according to the invention, the channel structure is designed such that, between the at least one valve structure and the one or more ultrasound generating elements, a resonance frequency of the one or more ultrasound generating elements in the channel structure includes an acoustic half-wave or a multiple thereof, in order to form a standing sound wave. According to the present invention, a resonance frequency is understood to be a specific frequency at which a fluid pumping device or a structure, such as a valve structure, tends to vibrate with maximum amplitude when excited by an external force. This results in a resonance that leads to a significant increase in the vibration amplitude.

[0029] In a further advantageous embodiment of the fluid pump device proposed according to the invention, the one or more ultrasound generating elements are excited by the at least one excitation mechanism such that the one or more ultrasound generating elements have an excitation frequency corresponding to the natural frequency of the at least one valve structure. R.415781

[0030] - 7 -

[0031] In a further advantageous embodiment of the fluid pump device proposed according to the invention, the at least one valve structure is designed as a second vibrating diaphragm. The second vibrating diaphragm is clamped on both sides or on one side.

[0032] In a further advantageous embodiment of the fluid pump device proposed according to the invention, the channel structure and / or an inner channel wall has at least one bulge.

[0033] In a further advantageous embodiment of the fluid pumping device proposed according to the invention, the fluid pumping device comprises at least one pressure build-up element and / or at least one pressure release element.

[0034] In a further advantageous embodiment of the fluid pump device proposed according to the invention, the at least one pressure build-up element and the at least one pressure release element can be switched independently of each other and / or separately from each other by at least one excitation mechanism.

[0035] In a further advantageous embodiment of the fluid pumping device proposed according to the invention, the at least one pressure build-up element is arranged as a valve structure with a connection to at least one inner channel wall designed in such a way that a fluid flow supports the closing of the valve structure in one flow direction, and the at least one pressure release element is arranged as a valve structure with a connection to at least one inner channel wall designed in such a way that the fluid flow supports the closing of the valve structure in such a way that the fluid flow enables the closing of the valve structure in a correspondingly different flow direction.

[0036] The pressure-reducing element is advantageously designed such that the fluid flow also assists in closing the valve structure, but in the opposite direction of fluid flow compared to the pressure-building element. In both cases, the fluid flow serves to assist in closing the valve and not to close it. R.415781

[0037] - 8 - to counteract, once for fluid flow in one direction and once for fluid flow in the opposite direction.

[0038] Furthermore, according to the invention, the use of at least one fluid pump device in a microelectromechanical system (MEMS) is proposed.

[0039] Advantages of the invention

[0040] The fluid pump device according to the invention enables the efficient generation of sound waves in the audible range by means of ultrasonic modulation. Among other things, this allows for precise control of the generated sound as well as fine-tuning of the audio output to application-specific requirements.

[0041] An advantageous embodiment of the fluid pumping system comprises at least two channels in a channel structure, which has at least one valve structure that can be actively controlled by the excitation mechanism. The at least one actively controllable valve structure enables advantageous control of the flow rate within the at least one channel as well as of the overall fluid pumping system.

[0042] The actively controllable valve structure according to the invention offers advantages in the flow control of a fluid within a fluid pump device, which makes the valve structure particularly useful for applications in MEMS loudspeakers.

[0043] The actively controlled valve structure advantageously generates precise flow control, which is crucial for accurate regulation and adaptation to various operating conditions of the fluid pumping device. Furthermore, precise flow control allows the fluid pumping device to operate more efficiently, resulting in improved system performance and enhanced generation of sound waves in the audible range. R.415781

[0044] - 9 -

[0045] Furthermore, active valve structures react dynamically to changes in the system and enable dynamic adaptation to changing requirements.

[0046] The fluid pump device according to the invention also allows the combination of several ultrasound generating elements, which, in the application as a MEMS loudspeaker, for example, opens up the possibility of operating ultrasound units in opposite phases and thus an extension of the functional spectrum. This allows a suppression of the ultrasound waves emitted by the ultrasound generating elements by interference, which effectively prevents ultrasound exposure of the user.

[0047] Brief description of the drawings

[0048] Embodiments of the invention are explained in more detail with reference to the drawings and the following description.

[0049] They show:

[0050] Figure 1 is a graphical representation of the basic principle of ultrasound modulation for generating audible audio signals using a pump signal.

[0051] Figure 2.1 shows a schematic representation of a fluid pumping device in a first active state,

[0052] Figure 2.2 shows a schematic representation of a fluid pumping device in a second active state,

[0053] Figure 3.1 shows a schematic representation of a fluid pumping device with an ultrasonic generating element arranged parallel to the valve structure in a first state,

[0054] Figure 3.2 shows a schematic representation of a fluid pump device with an ultrasonic generating element arranged parallel to the valve structure in a second state, R.415781

[0055] - 10 -

[0056] Figure 4 shows a schematic representation of a fluid pumping device with two ultrasound generating elements arranged parallel to the valve structure.

[0057] Figure 5 shows a schematic representation of a fluid pumping device with a valve structure designed as a second oscillating diaphragm,

[0058] Figure 6.1 shows a schematic representation of a fluid pumping device with bulges in a first state,

[0059] Figure 6.2 shows a schematic representation of a fluid pumping device with bulges in a second state,

[0060] Figure 7 shows a schematic representation of a fluid pumping device with a pressure reduction element and a pressure build-up element.

[0061] Figure 8.1 shows a schematic representation of a side view of a fluid pumping device comprising a semiconductor substrate, and

[0062] Figure 8.2 shows a schematic representation of a fluid pumping device with a semiconductor substrate in top view.

[0063] Embodiments of the invention

[0064] 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.

[0065] Figure 1 shows the basic principle of ultrasonic modulation 100 of audible audio signals 108. In this process, a pumping signal 106 is generated in a closed volume, for example, the ear canal, at an ultrasonic frequency. Figure 1 also shows a graph representing time 102 on the x-axis and pressure 104 on the y-axis. A pumping signal 106 with a specific frequency is shown, which changes the pressure 104 in the closed volume R.415781.

[0066] - 11 - periodically increased and decreased. This pump signal 106 is crucial for how precisely a desired audio signal can be modulated.

[0067] Figure 2.1 shows a schematic representation of a fluid pump device 200 in a first state 232. The first state 232 symbolizes an actuation of an ultrasonic generating element 202 opposite an x-direction 207.1. Furthermore, in Figure 2.1, the ultrasonic generating element 202 is shown, in the illustrated embodiment as a first vibrating membrane 203 that generates an ultrasonic vibration. In the illustrated embodiment, a first principal extension direction 204 of the first vibrating membrane 203 extends in the z-direction 207.3 and a second principal extension direction 206 of the first vibrating membrane 203 extends in the y-direction 207.2. Figure 2.1 shows that a channel structure 226 with channel walls, namely a first channel wall 214.1 and a second channel wall 214.1, is present.

[0068] 214.2 and an inner channel wall 214.3. Furthermore, it can be seen from Figure 2.1 that the ultrasound generating element 202 is coupled via a first channel 228 and a second channel 230. In the illustrated embodiment, the channels 228 and 230 extend in the x-direction 207.1, their height extends in the z-direction 207.3, and the depth of the first channel 228 and the second channel 230 extends in the y-direction 207.2.

[0069] In the illustrated exemplary embodiment, the first channel 228 is partially closed by a valve structure 212. The valve structure 212 is firmly anchored only to the inner channel wall 214.3 via an anchoring 216; another end of the valve structure 212, namely a freely movable end part 218 of the valve structure 212, is free to move. The extent of the valve structure 212 is dimensioned such that its depth (y-direction 207.2) is less than the depth of the channels 228, 230, in order to ensure freedom of movement of the valve structure 212, but is large enough to effectively seal the second channel 230 against a fluid flow 222. Ideally, the extent of the valve structure 212 in the y-direction 207.2 deviates by < 10 pm, namely 5 pm per side of the valve structure 212, particularly advantageously < 2 pm (1 pm per side of the valve structure 212), from the extent of the channel 228, 230 in the y-direction.

[0070] 207.2 from.

[0071] The fluid pump device 200 is in the first active state (232), which is shown in Figure 2.1. The first vibrating diaphragm 203 of the R.415781

[0072] - 12 -

[0073] Fluid pump device 200 exhibits a deflection opposite to the x-direction 207.1. This results in the generation of a fluid flow 222 in the first channel 228 and the second channel 230. Consequently, the valve structure 212 causes the first channel 228 to close, thereby significantly increasing the flow resistance in the first channel 228 and resulting in an interrupted fluid flow 224. This results in a larger fluid volume being drawn in through the second channel 230 than through the first channel 228.

[0074] Figure 2.2 shows a schematic representation of a fluid pump device 200 in a second active state (234). The first state (232) symbolizes the actuation of an ultrasonic generating element 202 in an x-direction 207.1. Furthermore, in Figure 2.2, the ultrasonic generating element 202 is shown, in the illustrated embodiment, as a first vibrating membrane 203 that generates an ultrasonic vibration. In the illustrated embodiment, a first principal extension direction 204 of the first vibrating membrane 203 extends in the z-direction 207.3 and a second principal extension direction 206 of the first vibrating membrane 203 extends in the y-direction 207.2. Figure 2.2 shows that a channel structure 226 with channel walls, namely a first channel wall 214.1 and a second channel wall 214.1, is present.

[0075] 214.2 and an inner channel wall 214.3. Furthermore, it is shown in Figure

[0076] 2.2 It can be seen that the ultrasound generating element 202 is coupled via a first channel 228 and a second channel 230. In the illustrated embodiment, the channels 228, 230 extend in the x-direction 207.1, their height extends in the z-direction 207.3 and a depth of the channels 228, 230 extends in the y-direction 207.2.

[0077] In the illustrated exemplary embodiment, the second channel 230 is partially closed by a valve structure 212. The valve structure 212 is fixedly anchored only to the inner channel wall 214.3 via an anchoring 216; another end of the valve structure 212, namely a freely movable end part 218, is free to move. The extent of the valve structure 212 is dimensioned such that its depth (y-direction 207.2) is less than the depth of the channels 228, 230 to ensure freedom of movement for the valve structure 212, but large enough to effectively seal the second channel 230 against a fluid flow 222. Ideally, the extent of the valve structure 212 deviates by < 10 pm in the y-direction 207.2, namely 5 pm per side of R.415781.

[0078] - 13 -

[0079] Valve structure 212, particularly advantageous < 2 pm (1 pm per side of the valve structure 212), from the extent of the channel 228, 230 in the y-direction 207.2.

[0080] The fluid pumping device 200 is in the second active state (234), which is shown in Figure 2.2. The first oscillating diaphragm 203 of the fluid pumping device 200 exhibits a deflection in the x-direction 207.1. This results in the generation of a fluid flow 222 in the first channel 228 and the second channel 230. Consequently, the valve structure 212 closes the second channel 230, significantly increasing the flow resistance in the second channel 230 and interrupting the fluid flow 224. This results in a larger fluid volume being drawn in through the first channel 228 than through the second channel 230.

[0081] Figure 3.1 shows a schematic representation of a fluid pump device 200 with an ultrasonic generating element 202 arranged parallel to the valve structure 212 in a first state 232. Furthermore, the ultrasonic generating element 202 is also arranged parallel to the first channel 228 and the second channel 230. The first state 232 symbolizes the activation of the ultrasonic generating element 202 in a z-direction 207.3. In the illustrated embodiment, the ultrasonic generating element 202 is further depicted in Figure 3.1 as a first vibrating diaphragm 203, which generates an ultrasonic vibration. In the illustrated embodiment, a first principal extension direction 204 of the first vibrating diaphragm 203 extends in the z-direction 207.3, and a second principal extension direction 206 of the first vibrating diaphragm 203 extends in the x-direction 207.1. Figure 3.1 shows that a channel structure 226 with channel walls, namely a first channel wall 214.1, a second channel wall 214.2 and an inner channel wall 214.3. Furthermore, as can be seen in Figure 3.1, the ultrasound generating element 202 is formed around or above the first channel 228. In the illustrated exemplary embodiment, the channels 228, 230 extend in the x-direction 207.1, their height extends in the z-direction 207.3, and a depth of the channels 228, 230 extends in the y-direction 207.2.

[0082] In the illustrated exemplary embodiment, the first channel 228 is partially closed by a valve structure 212. The valve structure 212 is firmly anchored only to the inner channel wall 214.3 via an anchoring 216, R.415781

[0083] - 14 - Another end of the valve structure 212, namely a freely movable end part 218 of the valve structure 212, is free from movement. The extent of the valve structure 212 is dimensioned such that its depth (y-direction 207.2) is less than the depth of the channels 228, 230, in order to ensure freedom of movement of the valve structure 212, but large enough to effectively seal the second channel 230 against a fluid flow 222. Ideally, the extent of the valve structure 212 in the y-direction 207.2 differs from the extent of the channels 228, 230 in the y-direction 207.2 by <10 pm, namely 5 pm per side of the valve structure 212, particularly advantageously by <2 pm (1 pm per side of the valve structure 212).

[0084] The fluid pumping device 200 is in the first state 232, which is shown in Figure 3.1. The first oscillating diaphragm 203 of the fluid pumping device 200 has a deflection in the z-direction 207.3, which leads to the generation of a fluid flow 222 in the first channel 228 and in the second channel 230, whereupon the valve structure 212 closes the first channel 228, thereby significantly increasing the flow resistance in the first channel 228 and interrupting the fluid flow 224. This results in a larger fluid volume being drawn in through the second channel 230 than through the first channel 228.

[0085] Figure 3.2 shows a schematic representation of a fluid pump device 200 with an ultrasonic generating element 202 arranged parallel to the valve structure 212 in a second state 234. Furthermore, the ultrasonic generating element 202 is also arranged parallel to the first channel 228 and the second channel 230. The first state 232 symbolizes the activation of the ultrasonic generating element 202 opposite to the z-direction 207.3. In the illustrated embodiment, the ultrasonic generating element 202 is further depicted in Figure 3.2 as a first vibrating diaphragm 203, which generates an ultrasonic vibration. In the illustrated embodiment, a first principal extension direction 204 of the first vibrating diaphragm 203 extends in the z-direction 207.3, and a second principal extension direction 206 of the first vibrating diaphragm 203 extends in the x-direction 207.1. Figure 3.2 shows that a channel structure 226 with channel walls, namely a first channel wall 214.1, a second channel wall 214.2 and an inner channel wall 214.3. Furthermore, Figure 3.2 shows that the ultrasound generating element 202 is formed around or above the first channel 228. In the illustrated exemplary R.415781.

[0086] - 15 -

[0087] In this embodiment, the channels 228, 230 extend in the x-direction 207.1, their height extends in the z-direction 207.3 and a depth of the channels 228, 230 extends in the y-direction 207.2.

[0088] In the illustrated exemplary embodiment, the first channel 228 is partially closed by a valve structure 212. The valve structure 212 is firmly anchored only to the inner channel wall 214.3 via an anchoring 216; another end of the valve structure 212, namely a freely movable end part 218, is free to move. The extent of the valve structure 212 is dimensioned such that its depth (y-direction 207.2) is less than the depth of the channels 228 and 230 to ensure freedom of movement for the valve structure 212, but large enough to effectively seal the second channel 230 against a fluid flow 222. Ideally, the extent of the valve structure 212 in the y-direction 207.2 deviates by < 10 pm, namely 5 pm per side of the valve structure 212, particularly advantageously < 2 pm (1 pm per side of the valve structure 212), from the extent of the channels 228, 230 in the y-direction 207.2.

[0089] The fluid pumping device 200 is in the second state 234, which is shown in Figure 3.2. The first oscillating diaphragm 203 of the fluid pumping device 200 has a deflection in the z-direction 207.3, which leads to the generation of a fluid flow 222 in the first channel 228 and in the second channel 230, whereupon the valve structure 212 closes the second channel 230, thereby significantly increasing the flow resistance in the first channel 230 and interrupting the fluid flow 224. This results in a larger fluid volume being drawn in through the first channel 228 than through the second channel 230.

[0090] Figure 4 shows a schematic representation of a fluid pump device 200 with two ultrasonic generating elements 202 arranged parallel to the valve structure 212 in a first state 232. The ultrasonic generating element 202 is also arranged parallel to the first channel 228 and the second channel 230. The first state 232 symbolizes activation of the ultrasonic generating elements 202 in the z-direction 207.3. Furthermore, Figure 4 shows the ultrasonic generating elements 202, in the illustrated embodiment as a first vibrating membrane 203, which generates an ultrasonic vibration. In the illustrated embodiment, a first principal direction of extension 204 of the first vibrating membrane 203 extends...

[0091] - 16 -

[0092] Membrane 203 extends in the z-direction 207.3, while a second principal direction of extension 206 of the first vibrating membrane 203 extends in the x-direction 207.1. According to Figure 4, a channel structure 226 with channel walls is provided, comprising a first channel wall 214.1, a second channel wall 214.2, and an inner channel wall 214.3. Furthermore, Figure 4 shows that the ultrasound generating element 202 is formed either around or above the first channel 228, and the other ultrasound generating element 202 is formed around or below the second channel 230. In the illustrated exemplary embodiment, the channels 228 and 230 extend in the x-direction 207.1, thus providing an extension in the y-direction 207.2. The height also extends in the z-direction 207.3. Channels 228 and 230 extend in the y-direction 207.2.

[0093] In the illustrated exemplary embodiment, the first channel 228 is partially closed by a valve structure 212. The valve structure 212 is fixed only to the inner channel wall 214.3 via an anchor 216, while another end of the valve structure 212, namely a freely movable end part 218, is free to move. The extent of the valve structure 212 is dimensioned such that its dimension in the y-direction 207.2 (depth) is less than the depth of the channels 228, 230. The channels 228, 230 are dimensioned such that freedom of movement of the valve structure 212 is ensured, while at the same time being large enough to guarantee an effective seal of the second channel 230 against a fluid flow 222. Ideally, the extent of the valve structure 212 in the y-direction 207.2 is < 10 pm, i.e. 5 pm per side of the valve structure 212.It has proven advantageous if the extent of the channels 228, 230 in the y-direction 207.2 is 2 pm (1 pm per side of the valve structure 212) smaller than the extent of the valve structure 212.

[0094] The fluid pumping device 200 shown in Figure 4 is in the first state 232. The first oscillating diaphragms 203 of the fluid pumping device 200 exhibit a deflection in the z-direction 207.3, thereby generating a fluid flow 222 in the first channel 228 and in the second channel. This leads to an interruption of the fluid flow 224 in the first channel 228, causing a larger fluid volume to be drawn in through the second channel 230. R.415781

[0095] - 17 -

[0096] Figure 5 shows a schematic representation of a fluid pumping device 200, which corresponds to that of the fluid pumping device 200 from Figures 2.1 and 2.2 with an alternatively configured valve structure 212 as a second oscillating diaphragm 502. The second oscillating diaphragm 502 can be actuated into a third state 504.1 or a fourth state 504.2. The second oscillating diaphragm 502 is fixed to the inner channel wall 214.3 by a double-sided anchor 216. Actuating the second oscillating diaphragm 502 causes a narrowing 506.1, 506.2 of the channels 228, 230, thereby increasing the fluid flow 222 in the corresponding channels 228, 230.

[0097] Figure 6.1 shows a schematic representation of a fluid pumping device 200, which corresponds to that of the fluid pumping device 200 from Figures 2.1 and 2.2, but with a number of protrusions 602 on the first channel wall 214.1, the second channel wall 214.2, and the inner channel wall 214.3. Furthermore, the fluid pumping device 200 comprises two valve structures 212, which are anchored to the inner channel wall 214.3. The embodiment shown in Figure 6.1 generates fluid flows 222, which assist in deflection of the valve structures 212. The fluid flow 222 acts on the valve structures 212 and thus, in a first state 232, additionally closes the second channel 230, thereby increasing the efficiency of the closure. The described effect is evident both when a volume is drawn in through one of the channels 228, 230 (movement of the ultrasound generating element 202 against the x-direction 207).1) as well as during the pumping process of that same volume through the corresponding other channel.

[0098] Figure 6.2 shows a schematic representation of a fluid pumping device 200, which corresponds to that of the fluid pumping device 200 from Figures 2.1 and 2.2, but with a number of protrusions 602 on the first channel wall 214.1, the second channel wall 214.2, and the inner channel wall 214.3. Furthermore, the fluid pumping device 200 comprises two valve structures 212, which are anchored to the inner channel wall 214.3. The embodiment shown in Figure 6.2 generates fluid flows 222, which assist in the deflection of the valve structures 212. The fluid flow 222 acts on the valve structures 212 and thus closes them in a second state 234 R.415781.

[0099] - 18 - additionally the first channel 228, thereby increasing the efficiency of the closure of the first channel 228.

[0100] Figure 7 shows a schematic representation of a fluid pumping device 200, which corresponds to that of the fluid pumping device 200 from Figures 2.1 and 2.2, but with a pressure-reducing element 704 and a pressure-building element 702. The pressure-building element 702 is equipped with two valve structures 212, which are anchored to the inner channel wall 214.3. The inner channel wall 214.3 also has protrusions 602 in the pressure-building element 702, thereby creating a pumping mechanism 706 that increases the pressure in the system. The pressure-reducing element 704 is equipped with two valve structures 212, each of which functions as a second oscillating diaphragm 502. This results in the creation of a tension mechanism 708.

[0101] Figures 2.1 to 7 each also show a first volume 208 and a second volume 210. The first volume 208 corresponds, for example, to an ear canal and the second volume 210 to a volume relative to the environment.

[0102] Figure 8.1 shows a semiconductor substrate 802 whose main extension directions are in the x-direction 207.1 and y-direction 207.2, and whose thickness extends along the z-direction 207.3. Figure 8.1 also indicates a channel structure 226, which, for example, comprises channels 228 and 230 arranged one behind the other in the z-direction 207.3. The channels 228 and 230 are provided with an open side 806 and a closed side 804 in the x-direction 207.1, the closed side 804 being sealed by a closure, the dimensions of which are shown by way of example. The channels 228 and 230 are partially closed upwards in the z-direction 207.3 by a cover layer 808.Above the cover layer 808, an ultrasonic generating element 202, for example a first vibrating membrane 203, is arranged, which completely seals the fluid pumping device 200 and is connected to the channels 228, 230 via an opening between the cover layer 808 and the side walls. The side walls, which seal the fluid pumping device 200 parallel to the xz-plane, are not shown in Figure 8.1. R.415781.

[0103] - 19 -

[0104] The vibrations of the ultrasound generating element 202 create a fluid flow 222 in the channel structure 226, which is open to the environment. The valve structures 212 in the channels 228, 230 generate a directed pumping effect from one of the two surrounding volumes to the other.

[0105] The same semiconductor substrate 802 is shown in a top view in Figure 8.2. The semiconductor substrate 802 shown in Figure 2 has a channel structure 226 with channels 228, 230 in the x-direction 207.1, which extend at a height over the entire thickness of the semiconductor substrate 802 or, for example, only over selected areas in the z-direction 207.3. An optional region, not shown here, can be arranged below the semiconductor substrate 802, which, for example, comprises a handle wafer or a bottom-terminating layer to close off the channels 228, 230 in the z-direction 207.3. Optionally, another ultrasonic generating element 202 can also be arranged in this region, which provides an additional pump volume per pump cycle, thus achieving a symmetrical structure. Furthermore, Figure 8.Figure 2 shows a valve structure 212, which has a freely movable end part 218 and an anchoring 216 on the inner channel wall 214.3. The valve structure 212 is inserted into the channels 228, 230 in such a way that a direction-dependent flow resistance is generated.

[0106] The structure of the semiconductor device 802 shown in Figures 8.1 and 8.2 is compatible with all previously described embodiments of a fluid pump device 200. Furthermore, all valve structures 212 shown in Figures 2.1 to 8 are advantageously actively controllable by an excitation mechanism.

[0107] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, within the scope specified by the claims, a multitude of modifications are possible that fall within the bounds of what is considered skilled in the art.

Claims

1. R.415781 - 20 - Claims 1. Fluid pumping device (200) for generating sound waves in an audible range comprising: a channel structure (226), wherein the channel structure (226) has at least two channels (228, 230) which are coupled, wherein the channels (228, 230) each have a volume (208, 210), wherein each volume (208, 210) has a different dimension or the same dimension, wherein the at least two channels (228, 230) are separated by at least one inner channel wall (214).3) are separated, one or more ultrasound generating elements (202) which are arranged either transversely or parallel to the channels (228, 230) and are operable at a frequency to pump defined volumes of fluid between the respective volumes (208, 210) of the channels (228, 230), wherein a pumping direction from one volume to the other volume (208, 210) is variable, and at least one valve structure (212), wherein the at least one valve structure (212) is actively controllable and is designed such that at least one valve structure (212) is operable in both a pumping and a suction state and has a vibration in resonance with the ultrasonic vibration of an ultrasonic source to generate effective ultrasonic modulation, and at least one excitation mechanism for exciting the one or the more valve structures (212).

2. Fluid pump device (200) according to claim 1 or 2, wherein the ultrasound generating element (202) is a first vibrating membrane (203). R.415781 - 21 - 3. Fluid pumping device (200) according to one of the preceding claims, wherein the at least one valve structure (212) has a natural frequency corresponding to an excitation frequency.

4. Fluid pump device (200) according to one of the preceding claims, wherein the channel structure (226) is designed such that between the at least one valve structure (212) and the one or more ultrasound generating elements (202) a resonance frequency of the one or more ultrasound generating elements (202) in the channel structure (226) includes an acoustic half-wave or a multiple of an acoustic half-wave to form a standing sound wave.

5. Fluid pump device (200) according to claim 3 or 4, wherein the one or more ultrasound generating elements (202) are excited by the at least one excitation mechanism such that the one or more ultrasound generating elements (202) have an excitation frequency according to the natural frequency of the at least one valve structure (212).

6. Fluid pumping device (200) according to one of the preceding claims, wherein the at least one valve structure (212) is designed as a second oscillating diaphragm (502), wherein the second oscillating diaphragm (502) is clamped on both sides or on one side.

7. Fluid pumping device (200) according to one of the preceding claims, wherein the channel structure (226) and / or an inner channel wall (214.3) has at least one bulge (602).

8. Fluid pumping device (200) according to one of the preceding claims, wherein the fluid pumping device (200) comprises at least one pressure build-up element (702) and / or at least one pressure release element (704).

9. Fluid pumping device (200) according to claim 8, wherein the at least one pressure build-up element (702) and the at least one R.415781 - 22 - The pressure relief element (704) can be switched independently of each other and / or separately from each other by at least one excitation mechanism.

10. Fluid pumping device (200) according to claim 8 or 9, wherein the at least one pressure build-up element (702) is arranged as a valve structure (212) with a connection designed such that a fluid flow supports the closing of the valve structure (212) in one flow direction, and the at least one pressure release element (704) is arranged as a valve structure (212) with a connection designed such that the fluid flow supports the closing of the valve structure (212) in such a way that the fluid flow enables the closing of the valve structure (212) in a correspondingly different flow direction.

11. Use of at least one fluid pump device (200) according to one of the preceding claims in a microelectromechanical system (ME MS).

Images