Microfluidic delivery system and method for operating a microfluidic delivery system

Abstract

The invention relates to a microfluidic transport system (10) comprising a substrate (28), a chamber (30) configured in the substrate (28), a top and a bottom region (54, 56) delimiting the chamber (30), a first and a second opening (40, 42) enabling a flow of medium (12) through the chamber (30). The chamber (30) is assigned at least one pressure difference generating means (34, 36). The pressure difference is modulated by a valve structure 1 and 2 (14, 16) into a directed flow of medium (12). Furthermore, the invention relates to the use of the microfluidic transport system (10) in a MEMS-based loudspeaker, in particular in a micro loudspeaker (µ-loudspeaker).

Description

Technical Field

[0001] This invention relates to a microfluidic delivery system having a substrate and a chamber constructed within the substrate, wherein the chamber is bounded by a top region and a bottom region, and wherein a first opening and a second opening enable media exchange through the chamber. Furthermore, the invention relates to a method for operating the microfluidic delivery system and applications of the microfluidic delivery system. Background Technology

[0002] DE 10 2017 203 722 A1 describes a microelectromechanical system (MEMS) with movable elements comprising three electrodes, wherein the movable elements are configured to move according to the potential between the electrodes. In this case, the electrodes may be connected to a substrate via spring elements. The MEMS can be part of a MEMS transducer, such as a speaker, pump, or valve. A substrate comprising multiple layers and a MEMS structure introduced into an intermediate layer is disclosed, wherein the MEMS structure is surrounded by fluid. The surrounding fluid can be moved by the movement of the movable elements within the MEMS due to manipulation of the electrodes. The MEMS transducer is also used as a MEMS pump by arranging passive valves that reduce or block fluid flow in one direction.

[0003] DE 10 2017 206 766 A1 relates to a MEMS transducer that can be used as a MEMS pump, wherein the MEMS transducer has two deformable elements with a beam structure, the deformable elements being clamped on both sides of a substrate. Alternatively, MEMS transducers having only one deformable element or more than two deformable elements are also disclosed. The deformable elements may be present adjacent to a valve structure, wherein the valve structure is configured to reduce or prevent the flow of volumetric flow through an opening in at least one direction. Here, the valve structure may be passively configured as a backflow valve or may be actively configured, meaning that the valve structure may also be directly controllable. The MEMS transducer may be configured such that the deformable elements are configured as capacitor plates that move toward each other due to a potential difference until a corresponding mechanical reaction force is applied by an element acting as a bending spring.

[0004] EP 3 474 572 A1 discloses a MEMS device having a front support element, a rear support element, and a folded diaphragm. The folded diaphragm is mounted on the support element such that it is connected to the front and rear templates and forms two chambers. Here, the diaphragm is arranged near multiple valves. The diaphragm comprises multiple diaphragm units, wherein, in one embodiment, piezoelectric electrodes are applied to one side of each diaphragm unit such that the diaphragm unit can be horizontally deformed in one direction. Here, the horizontal deformation of the diaphragm unit increases or decreases the pressure in the two chambers.

[0005] MEMS-based loudspeakers (µ loudspeakers) have enormous market potential due to their superior sound quality with potentially lower energy consumption. However, many approaches have issues regarding achieving sufficiently high acoustic power. One factor is that higher acoustic power requires increased displacement volume. Increased displacement volume can be achieved, for example, through higher diaphragm deflection and through larger chip size. However, both approaches should be avoided from an economic perspective, as chip size is a significant factor in determining product cost, for example. Different approaches are conceivable to achieve high acoustic power with small chip size. One possible solution for achieving sufficiently high SPLs (Sound Pressure Levels), especially in the lower frequency range, is ultrasonic modulation, as described, for example, by US 2022 / 224999 A1. This approach is based on a pump-like structure and one or more valve devices to modulate the target frequency through targeted pressure build-up and pressure reduction.

[0006] However, existing solutions primarily utilize a vibrating diaphragm structure as a valve, which closes or opens based on its relative phase. This results in relatively high power losses that reduce pump efficiency. This, in turn, directly impacts the achievable acoustic power of the components. Summary of the Invention

[0007] According to the present invention, a microfluidic delivery system is provided, comprising: -Base, -Cavities constructed within the substrate -The top and bottom regions of the boundary chamber, - A first opening and a second opening, the first opening and the second opening enabling media exchange through a chamber, wherein the chamber is equipped with at least one component that generates a pressure difference, and the pressure difference is modulated by a controlled valve structure to form a directional media flow.

[0008] The solution proposed according to the invention allows the openings to be opened and closed alternately, thus enabling the flow of media into and out of the chamber. The solution proposed according to the invention also allows for the advantageous generation of directional pumping flow in one direction or another with proper switching.

[0009] In an advantageous manner, at least one component that generates a pressure difference is implemented as an electrode structure with a planar or comb-like configuration, and valve structure 1 and valve structure 2 each include at least one movable valve element.

[0010] Furthermore, the microfluidic delivery system proposed according to the present invention is characterized in that at least one movable valve interacts with at least one fixed component respectively housed in a chamber.

[0011] In an advantageous further extension of the microfluidic delivery system, at least one fixed valve element is constructed within the chamber on a protrusion of the frame structure surrounding the chamber.

[0012] Furthermore, in the microfluidic delivery system according to the present invention, valve structure 1 and valve structure 2 respectively have movable valve elements and fixed valve elements, or each has individual thin sheet elements arranged in a comb-like structure that can be placed to overlap or not overlap each other, for opening or closing the first opening and the second opening.

[0013] In an advantageous manner, in the microfluidic delivery system according to the invention, at least one movable valve element is elastically supported on the inner side of the frame structure of the boundary chamber and preloaded by at least one spring structure. The spring structure allows for a simple and convenient reset of each movable valve element.

[0014] Furthermore, in the microfluidic delivery system proposed according to the present invention, the electrode structures are arranged opposite to each other within the chamber, and each has a first electrode, a second electrode, a third electrode, and a fourth electrode.

[0015] In the microfluidic delivery system proposed according to the present invention, the first electrode and the third electrode are arranged facing the cavity on the inner side of the frame structure.

[0016] In an advantageous manner, the microfluidic delivery system is constructed such that the second and fourth electrodes are arranged on the back side of the movable valve. This results in a particularly narrow structural form for the microfluidic delivery system.

[0017] In the microfluidic delivery system according to the invention, an electrode structure having a first electrode, a second electrode, a third electrode, and a fourth electrode is provided with electrode fingers that are interlocked with each other in a comb-like manner.

[0018] In addition to arranging planar electrodes, electrodes can also have comb-shaped electrode fingers facing each other, allowing for different structural forms.

[0019] Furthermore, the present invention relates to a method for operating a microfluidic delivery system, comprising at least the following method steps: a) Valve structure 1 and valve structure 2 are subjected to vibration via an energized counter electrode structure, such that... b) With the electrodes facing each other, the first and third electrodes are applied with a DC voltage and the second and fourth electrodes are applied with an AC voltage, or c) On the electrodes facing each other, the first and third electrodes are applied with an alternating voltage, and the second and fourth electrodes are applied with a direct current voltage. d) The second electrode operates with a 180° phase shift relative to the fourth electrode, such that e) Generates the same directional movement of the valve structure.

[0020] By means of the method proposed in this invention, the proposed microfluidic delivery system can deliver a continuous flow of medium through a chamber, thereby achieving high pump efficiency.

[0021] Furthermore, the method proposed according to the present invention is characterized in that, in a passive state, the first and second electrodes of electrode structure 1, which are respectively opposite to each other, and the third and fourth electrodes of electrode structure 2 operate with voltages of the same polarity, thereby increasing the spacing between the electrodes.

[0022] Furthermore, in the method proposed according to the present invention, in the passive state, the first opening is closed due to the valve structure 1, while at the same time the valve structure 2 opens the second opening of the chamber due to the third electrode and the fourth electrode operating with voltages of opposite polarities, and a medium flow is generated.

[0023] The method according to the invention enables the alternating opening and closing of the first and second openings, thereby generating a medium flow into and out of the chamber. This medium flow is generated, for example, by coupling ultrasonic vibrations produced by at least one diaphragm-configured ultrasonic generating element assigned to the chamber. At least one ultrasonic vibration is modulated via valve structure 1 and valve structure 2.

[0024] Furthermore, in the method proposed according to the invention, the electrode structure is configured to operate within the resonant range. Operating the electrode structure within the resonant range enables extremely energy-efficient actuation. The corresponding resonance can be tuned by the mass or stiffness of the components. In particular, the resonant frequency must be adapted to the ultrasonic frequency to be modulated, so that a directional medium flow is generated by correctly opening valve structure 1 and valve structure 2 in time. Here, the ultrasonic frequency can be freely selected. Depending on the desired application, for example in the case of a µ-loudspeaker (acoustic application), an ultrasonic frequency in the range exceeding 20 kHz is selected. However, in other applications, the frequency or frequency band can be in a significantly different range.

[0025] Finally, the present invention relates to the application of the microfluidic delivery system and method for operating MEMS-based loudspeakers, particularly micro-loudspeakers (µ loudspeakers). Particularly efficient valve structures can be formed, for example, by two valve structures either planarly driven by electrodes arranged relative to each other, or driven by a comb-shaped actuator composed of electrodes. The solution proposed in this invention offers the possibility of increasing pump power, for example, in the case of a pump-type loudspeaker, and thus improving the overall efficiency of the component. In particular, the proposed microfluidic delivery system can operate within the resonant range, thereby achieving very low energy requirements.

[0026] Advantages of the invention According to the solution proposed in this invention, at least two first and second openings arranged horizontally or vertically around the chamber in the frame structure can be alternately opened and closed, enabling continuous flow of media into and out of the chamber of the microfluidic delivery system. Through precise switching, directional pumping flow in one or the other direction can thus be generated.

[0027] The solution proposed according to the invention can also be used for ultrasonic modulation of media flow by adding at least one ultrasonic generating component, for example, in a diaphragm configuration. At least one ultrasonic generating component can be integrated, for example, into the frame structure of the substrate of the microfluidic system, or into the top or bottom region. The advantage of the microfluidic system proposed according to the invention is its very high efficiency, because not only at least one ultrasonic generating component but also the valve structure can operate within the resonant range. Furthermore, the illustrated valve structure has the advantage of a particularly high shut-off degree, thereby enabling very high pump efficiency.

[0028] The solution proposed in this invention forms a microfluidic delivery system with significantly improved sound pressure level (SPL).

[0029] The solution proposed according to the present invention enables active control by precisely selecting the phase difference between the valve and the drive structure, i.e., the electrode structure, allowing the intensity of the pumping impact of the medium flow to be freely selected according to the application. Furthermore, the pumping direction of the medium flow can be advantageously reversed. The phase difference can be achieved between the valve structure and the electrode structure, allowing the components to be configured for both pumping and suction. The drive structure, in the form of an electrode structure, covers the valve structure containing a comb-like structure, resulting in reduced chip area requirements and thus an area-optimized structure. Attached Figure Description

[0030] Embodiments of the present invention will be further explained with reference to the accompanying drawings and the following description.

[0031] The attached diagram shows: Figure 1a , 1b The first embodiment variant of the microfluidic delivery system according to the present invention is shown in top and side views. Figure 2a , 2b The following are top and side views illustrating variations of the microfluidic delivery system with a comb-shaped electrode structure proposed according to the present invention. Figure 3a , 3b The following is a top and side view illustrating another embodiment of the microfluidic delivery system according to the present invention, which has a comb-shaped electrode structure and movable and fixed valves constructed in the comb-shaped structure. Figures 4a-4d : A schematic diagram of another embodiment variant of the microfluidic delivery system according to the present invention is shown in top and side views, having a first opening and a second opening constructed in the bottom region and / or the top region, and Figure 5a , 5b According to another embodiment of the microfluidic delivery system proposed by the present invention, in which movable valves are interconnected by a connecting structure. Detailed Implementation

[0032] In the following description of embodiments of the invention, the same or similar elements are identified by the same reference numerals, and repeated descriptions of elements are omitted in certain cases. The accompanying drawings are for illustrative purposes only, showing the subject matter of the invention.

[0033] Figure 1a and 1b A first embodiment variant of the microfluidic delivery system 10 proposed according to the present invention is shown in top and side views.

[0034] The microfluidic delivery system 10 delivers a medium flow 12 in a pump-like manner. In the medium flow 12, gaseous or liquid media move through the chamber 30 of the microfluidic delivery system 10 within a media exchange framework. For this purpose, valve structures 114 and 216 are provided. Valve structure 114 includes a movable valve element 18 and a fixed valve element 20. Valve structure 216 includes a movable valve element 22 and a fixed valve element 24. These valve elements are respectively assigned to a first opening 40 or a second opening 42 in the top view according to FIG1. ​​With the aid of valve structures 114 and 216, the first opening 40 and the second opening 42 of the microfluidic delivery system 10 can be alternately opened and closed, thereby generating a medium flow 12 flowing into and out of the chamber 30 of the microfluidic delivery system 10. Valve structures 114 and 216 are elastically supported on the sides of the frame structure 32 surrounding the chamber 30. At least one spring structure 26 serves as an elastic support. Multiple spring structures 26, not shown in the figure, can also be provided to support and preload the movable valve elements 18, 22 of valve structure 1 14 and valve structure 2 16.

[0035] The movable valve elements 18 and 22 of valve structures 1 14 and 2 16 are complemented by valve elements 20 and 24 of the same construction that are fixed or immobilized on the frame structure 32 or on the protrusion 38 of the frame structure.

[0036] According to Figure 1a The top view also shows that valve structure 1 14 and valve structure 2 16 move via electrode structures, namely electrode structure 1 34 and another electrode structure 2 36. Valve structure 1 14 and valve structure 2 16 are excited to vibrate via electrode structures 1 34 and 2 36. Electrode structures 1 34 and 2 36, as they are in accordance with… Figure 1a As shown in the top view, each electrode structure 1 34 includes electrodes facing each other, namely, a first electrode 34.1 with a planar structure in Figure 1 and a second electrode 34.2 opposite to the first electrode, which is also planar. Similarly, electrode structure 2 36 includes a third electrode 36.1 with a planar structure and a fourth electrode 36.2 with the same planar structure. The second electrode 34.2 with a planar structure and the fourth electrode 36.2 with the same planar structure are respectively arranged on the back surface 58 of the movable valve members 18 and 22.

[0037] According to the first opening 40 and the second opening 42 Figure 1a The top view is perpendicular to the drawing plane and accordingly has a vertical orientation of 44. According to... Figure 1aIn the top view, the first opening 40 is closed 48 due to the valve structure 1 14, while the second opening 42, which is arranged opposite to the first opening, is open 50 due to the valve structure 2 16.

[0038] Here Figure 1a The first to fourth electrodes 34.1, 34.2, 36.1, and 36.2, which are planar structures and opposite to each other, can either be loaded with an AC voltage, or the complementary electrodes 34.1, 34.2, 36.1, and 36.2 can be loaded with a DC voltage. Figure 1a In the embodiment shown, the first electrode 34.1 and the third electrode 36.1 are loaded with a DC voltage, while the second electrode 34.2 and the fourth electrode 36.2 are loaded with an AC voltage. Here, the second electrode 34.2 operates with a 180° phase offset relative to the fourth electrode 36.2, thereby resulting in identical directional movement of the two valve structures 1 14 and 2 16.

[0039] In this case, it is possible to switch between which of the electrodes 1 to 4 34.1, 34.2, 36.1, and 36.2, which are constructed to complement each other, operate with AC voltage or DC voltage. Therefore, it is possible for the second electrode 34.2 and the fourth electrode 36.2 to be loaded with DC voltage, and for the first electrode 34.1 and the third electrode 36.1 to be loaded with AC voltage.

[0040] exist Figure 1a In the examples shown, for each valve structure 1 14 and valve structure 2 16, two electrodes loaded with AC voltage, namely the second electrode 34.2 and the fourth electrode 36.2, are shown, and two electrodes loaded with DC voltage, namely the first electrode 34.1 and the third electrode 36.1, are shown. This should not be construed as it is also possible to use only one electrode loaded with DC or AC voltage, or multiple such electrodes.

[0041] Valve structures 1 and 14 and valve structure 2 and 16 are complemented by the aforementioned fixed complementary structures, namely the aforementioned fixed valve elements 20 and 24. These valve elements, in a passive state, impede the flow of medium 12 through the first opening 40 and the second opening 42 between the interior of chamber 30 and its surrounding environment. The advantage of this passive state is that the complementary electrodes 1 to 4 34.1, 34.2, 36.1, 36.2 are loaded with voltages of the same polarity, thus preventing any attraction between these electrodes. By the spring force applied by the spring structure 26, the movable valve elements 18 and 22 of valve structure 1 and 14 are correspondingly pushed away from the frame structure 32. The spacing between the electrodes, here for example, between the first electrode 34.1 and the second electrode 34.2, is thus increased. In the example shown in the schematic diagram of Figure 1, valve structure 1 14 is in a passive state, thus the first opening 40 is closed, while valve structure 2 16 is in an active state, meaning that the third electrode 36.1 and the fourth electrode 36.2 operate with voltages of opposite polarities. Therefore, an attraction is applied between these electrodes and valve structure 2 16 moves towards frame structure 32, thereby opening the second opening 42 and generating a medium flow 12 or medium exchange 12 through chamber 30. This structure, schematically shown in the top view according to Figure 1, allows the first opening 40 and the second opening 42 to open and close alternately, thus enabling the medium flow 12 to flow into and out of chamber 30. Therefore, by proper switching, a directional pump flow in one direction or another can be generated. If chamber 30 is given as... Figure 1b The addition of an ultrasonic generating component 52 in the form of a diaphragm 52, as shown in the diagram, allows the microfluidic delivery system 10 proposed according to the present invention to be used for ultrasonic modulation. From the present invention... Figure 1b As shown in the schematic diagram, in the variant of the embodiment illustrated here, at least one ultrasound generating member 52 is located, for example, in the top region 54 above the chamber 30. Alternatively, it is possible that at least one ultrasound generating member 52 in a diaphragm configuration is arranged in the bottom region 56 on the lower side of the chamber 30 of the microfluidic delivery system 10. Multiple ultrasound generating members 52 may also be arranged in the bottom region 56 in the sidewalls of the chamber 30 and / or in the top region 54. By properly switching electrode structures 1 34 and 2 36, ultrasound waves coupled through at least one ultrasound generating member 52 can be modulated to form a pump-type loudspeaker. The advantage of this pump-type loudspeaker is its high efficiency, because not only the ultrasound generating member 52 but also both valve structures 1 14 and 2 16 can operate within the resonant range. Furthermore, in Figure 1a The advantages of valve structures 1 14 and 2 16, which are schematically shown in the diagram, are high shut-off efficiency, thereby enabling high pump efficiency.

[0042] According to Figure 2a and 2bThe schematic diagram shows a first alternative embodiment variant of the microfluidic delivery system 10 proposed according to the present invention, in which the electrodes 1 to 434.1, 34.2, 36.1, 36.2 for driving valve structures 1 14 and 2 16 are configured as comb-shaped actuators 60. In a second embodiment variant of the microfluidic delivery system 10 proposed according to the present invention, the electrodes 1 to 434.1, 34.2, 36.1, 36.2 are not implemented in a planar manner, but have electrode fingers 62 that extend perpendicularly to the respective movable valve elements 18 and 22 within the chamber 30. Figure 2a and 2b The comb-shaped actuator 60 shown can generate higher forces to move valve structures 1 14 and 2 16. The electrode fingers 62 of the first to fourth electrodes 34.1, 34.2, 36.1, 36.2 have multiple overlaps 64, as shown in the diagram. Figure 2a As shown in the top view. In addition, according to Figure 2a and 2b The second embodiment variant corresponds to in Figure 1a and 1b The first embodiment variant of the microfluidic delivery system 10 proposed according to the present invention is shown.

[0043] Electrode structures 134 and 236, configured to move the movable valve elements 18 and 22 of valve structures 1 14 and 2 16, can operate according to the following methods: a) Valve structures 1 and 14 and valve structure 2 and 16 are subjected to vibration via energizing electrode structures 34 and 36, causing b) With electrodes 34.1, 34.2, 36.1, and 36.2 facing each other, the first electrode 34.1 and the third electrode 36.1 are applied with a DC voltage, and the second electrode 34.2 and the fourth electrode 36.2 are applied with an AC voltage, or c) On the electrodes 34.1, 34.2, 36.1, and 36.2, which are positioned opposite each other, the first electrode 34.1 and the third electrode 36.1 operate with an alternating current voltage, while the second electrode 34.2 and the fourth electrode 36.2 operate with a direct current voltage. d) The second electrode 34.2 operates with a 180° phase offset relative to the fourth electrode 36.2, such that... e) Produce the same directional movement of valve structure 1 14 and valve structure 2 16.

[0044] Depend on Figure 3a and 3bThe schematic diagram illustrates a third embodiment variant of the microfluidic delivery system 10. Distinguished from the first and second embodiments of the microfluidic delivery system 10 proposed according to the present invention, this third embodiment variant is characterized in that valve structures 114 and 216 are themselves constructed as comb-like structures 70. This involves not only the movable valve elements 18 and 22 of valve structures 114 and 216, but also the fixed valve elements 20 and 24 of valve structures 114 and 216, which are fixedly arranged on the frame structure 32. The valve structures 114 and 216, or their movable valve elements 18 and 22, or their fixed valve elements 22 and 24, can be interlocked in the active state of valve structures 114 and 216, thereby further improving the shut-off effect of valve structures 114 and 216. The number of teeth or the cascaded arrangement 72 of the individual sheet elements 74 that can be used to construct the comb-like structure 70 according to the schematic diagrams 3a and 3b are variable and can be adapted as needed. Regarding the first opening 40 and the second opening 42, they are similar to variations of the aforementioned embodiment of the microfluidic delivery system 10 proposed according to the invention, but are located at the ends of the chamber 30 in a vertical orientation 44.

[0045] from Figure 4a and 4b A fourth embodiment variant of the microfluidic delivery system 10 according to the present invention can be seen in the schematic diagram. In this embodiment variant, the first opening 40 and the second opening 42 are not opened along the X direction, but are located in the plane on which the ultrasonic generating member 52, preferably configured as a diaphragm, can be arranged. The first opening 40 and the second opening 42 are openings along the Z direction in the fourth embodiment variant of the microfluidic delivery system 10 according to the present invention. The first opening 40 and the second opening 42 are opened or closed by moving the valve structure 1 14 and the valve structure 2 16 along the + / - Y direction. Figure 4a The schematic diagram shows a top view of the fourth embodiment variant. Figure 4b The cross-section along the Y / Z plane is shown. Figure 4c The cross-section along the X / Z plane is shown.

[0046] In the microfluidic delivery system 10 proposed according to the present invention Figures 4a to 4dIn the fourth embodiment variant shown, valve structures 1 14 and 2 16 have the same height along the Z direction as electrode structures 1 34 and 2 36, or their electrodes 1 to 4 34.1, 34.2, 36.1, 36.2. In another embodiment variant not shown here, it is possible that valve structures 1 14 and 2 16 could also be implemented lower or higher. Here, the width of valve structures 1 14 and 2 16 along the X direction corresponds to at least one opening width of the first opening 40 and the second opening 42, but is preferably greater than said opening width to ensure high shut-off efficiency.

[0047] Here, the positions of the first opening 40 and the second opening 42 can be changed, and either as in Figures 4a to 4d The openings are arranged as shown in the top region 54 or the bottom region 56 (not shown further here), or it is possible that one of the first opening 40 and the second opening 42 is arranged in the top region 54, as shown. Figure 4d As shown, another one is arranged in the bottom area 56.

[0048] Figure 5a and 5b A fifth embodiment variant of the microfluidic delivery system 10 according to the present invention is shown. In this embodiment variant, valve structure 1 14 and valve structure 2 16 are mechanically coupled to each other via a connection structure 80 with a basic planar structure. Therefore, the movements of the movable parts of valve structure 1 14 and valve structure 2 16, i.e., the movable valve parts 18 and 22, are coupled to each other, thereby ensuring the symmetrical movement of the two valve structures 1 14 and 2 16.

[0049] The connecting structure 80 can be configured as surface 42, which is the base plate 84, thereby effectively blocking acoustic leakage paths. Through mechanical coupling via the connecting structure 80, the spring structure 26, as previously described, does not need to function as a reset element. Therefore, limited control of valve structures 1 14 and 2 16 is possible, as the reset force is generated by the paired electrodes 1 to 4 34.1, 34.2, 36.1, and 36.2 arranged opposite to each other. This results in greater stability, especially against impacts and vibrations.

[0050] In all five illustrated embodiments of the microfluidic delivery system 10 proposed according to the present invention, multiple valve structures 1 14 and valve structures 2 16 may be used, which may operate in phase or out of phase with each other. In particular, by operating the valve structures 1 14 and valve structures 2 16 out of phase, a time gradient may be induced, for example, in the opening and thus in the medium flow 12.

[0051] The microfluidic delivery system 10 proposed according to the present invention can be used, for example, in MEMS, such as in a pump-type microphone in microfluidics, and can be used in MEMS-based micro-speakers (µ-speakers) in its foregoing performance.

[0052] The invention is not limited to the embodiments described herein and the aspects highlighted therein. Rather, various modifications that are within the scope of the claims are possible and are of skill to those skilled in the art.

Claims

1. A microfluidic delivery system (10), comprising: -Base (28) - A chamber (30) is constructed in the substrate (28). - The top and bottom regions (54, 56) of the chamber (30) are defined. - A first opening and a second opening (40, 42), the first opening and the second opening enabling the flow (12) of the medium through the chamber (30). The chamber (30) is characterized by having at least one component (34, 36) that generates a pressure difference, and the pressure difference is modulated by valve structures 1 and 2 (14, 16) to form a directional medium flow (12).

2. The microfluidic delivery system (10) according to claim 1, characterized in that The at least one component that generates the pressure difference is implemented as an electrode structure (34, 36) with a planar or comb-like structure, and the valve structures 1 and 2 (14, 16) each include at least one movable valve element (18, 22).

3. The microfluidic delivery system (10) according to claims 1 and 2, characterized in that, Each of the at least one movable valve (18, 22) and at least one fixed valve (20, 24) respectively housed in the chamber (30) work together.

4. The microfluidic delivery system (10) according to any one of claims 1 to 3, characterized in that, The at least one fixed valve (20, 24) is constructed in the chamber (30) on a protrusion (38) of the frame structure (32) surrounding the chamber (30).

5. The microfluidic delivery system (10) according to any one of claims 1 to 4, characterized in that, The valve structures 1 and 2 (14, 16) respectively have movable valve elements (18, 22) and fixed valve elements (20, 24), or It has individual sheet pieces (74) arranged in a comb-like structure (70) that can be placed to overlap or not overlap each other, to open or close the first opening and the second opening (40, 42).

6. The microfluidic delivery system (10) according to any one of claims 1 to 5, characterized in that, The at least one movable valve (18, 22) is elastically supported on the inside of the frame structure (32) that defines the chamber (30) and is preloaded by at least one spring structure (26).

7. The microfluidic delivery system (10) according to any one of claims 1 to 6, characterized in that, The electrode structures (34, 36) are arranged opposite to each other within the chamber (30), and the electrode structure 1 (34) has a first electrode and a second electrode (34.1, 34.2), and the electrode structure 2 (36) has a third electrode and a fourth electrode (36.1, 36.2).

8. The microfluidic delivery system (10) according to any one of claims 1 to 7, characterized in that, The first electrode and the third electrode (34.1, 36.1) are arranged on the inner side of the frame structure (32) facing the cavity (30).

9. The microfluidic delivery system (10) according to any one of claims 1 to 8, characterized in that, The second and fourth electrodes (34.2, 36.2) are arranged on the back (58) of the movable valve (18, 22).

10. The microfluidic delivery system (10) according to any one of claims 1 to 7, characterized in that, The electrode structures (34, 36) have a first electrode and a second electrode (34.1, 34.2) as well as a third electrode and a fourth electrode (36.1, 36.2), wherein the electrode fingers (62) of the comb-shaped actuator (60) are interlocked.

11. A method for operating the microfluidic delivery system (10) according to any one of claims 1 to 10, comprising at least the following method steps: a) The valve structures 1 and 2 (14, 16) are subjected to vibration by energizing the electrode structures (34, 36), such that b) With the electrodes (34.1, 34.2, 36.1, 36.2) facing each other, the first and third electrodes (34.1, 36.1) are applied with a DC voltage, and the second and fourth electrodes (34.2, 36.2) are applied with an AC voltage, or c) On the electrodes (34.1, 34.2, 36.1, 36.2) that are positioned opposite each other, the first and third electrodes (34.1, 36.1) operate with an alternating current voltage, and the second and fourth electrodes (34.2, 36.2) operate with a direct current voltage. d) The second electrode (34.2) operates with a 180° phase offset relative to the fourth electrode (36.2) such that e) Produce the same directional movement of the valve structures 1 and 2 (14, 16).

12. The method according to claim 11, characterized in that, In the passive state, especially in the closed state (48), the first and second electrodes (34.1, 34.2) of the electrode structure 1 (14) and the third and fourth electrodes (36.1, 36.2) of the electrode structure 2 (16), which are respectively opposite to each other, operate with voltages of the same polarity, thereby increasing the spacing between the electrodes.

13. The method according to claim 11 or 12, characterized in that, In the passive state, especially in the closed state (48), the first opening (40) is closed by the valve structure 1 (14), while at the same time the valve structure 2 (16) puts the second opening (42) of the chamber (30) in the open state (50) by the third and fourth electrodes (36.1, 36.2) operating with voltages of opposite polarities, thereby generating a medium flow (12).

14. The method according to any one of claims 11 to 13, characterized in that, The first opening and the second opening (40, 42) are opened and closed alternately to allow the flow (12) of medium into and out of the chamber (30).

15. The method according to any one of claims 11 to 14, characterized in that, The electrode structures (34, 36) operate within the resonance range.

16. The method according to any one of claims 11 to 15, characterized in that, The ultrasonic modulation of the medium flow (12) is performed by means of an ultrasonic generating element (52), in particular at least one diaphragm, arranged in the top region (54) and / or the bottom region (56), and in the case of acoustic applications, at a frequency of 30 kHz or higher, especially 20 kHz or higher.

17. The application of the microfluidic delivery system (10) according to any one of claims 1 to 10 and the method according to any one of claims 11 to 16 for operating a MEMS-based loudspeaker, especially a micro loudspeaker.

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