Microfluidic interaction element for generating and / or detecting volumetric flow of fluid and acoustic device having such microfluidic interaction element
By designing microfluidic interactive elements with cavity and vertical extrusion elements in microelectromechanical system speakers and microphones, the problem of insufficient sound level in the prior art is solved, and efficient acoustic energy conversion and miniaturization design are achieved.
Patent Information
- Application Number
- CN202380063802.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-09-05
- Filing Date
- 2023-07-13
- Publication Date
- 2025-04-15
Smart Images
Figure CN119836792A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a microfluidic interaction element for generating and / or detecting a volume flow of a fluid, which can be used in particular in a loudspeaker and / or a microphone. Background Art
[0002] Compared with conventional electronic dynamic loudspeakers and microphones, MEMS (micro-electromechanical systems) loudspeakers and microphones have significant advantages, such as less delay time, lower energy consumption, smaller structural dimensions or in principle weldability. On the other hand, the MEMS loudspeakers and microphones are still insufficient in terms of the achievable sound level. In order to achieve a high sound level, a correspondingly large volume of air must be extruded. The extruded volume can be maximized by a larger offset of a movable extrusion element, such as a diaphragm or a bending beam and / or by increasing the surface of the extrusion element. For micromechanical elements, on the one hand, due to the insufficient load capacity of the material / structure, on the other hand, due to the low force generation density, a larger offset is difficult to achieve. In addition, disadvantageously, the bending beam used for actuation is no longer mechanically robust and slight changes in its manufacturing tolerances cause the bending beam to move asynchronously, which reduces the achievable sound level. Although the increase in the horizontal plane of the extrusion element can be achieved more simply, it is counterproductive in terms of structural element size and cost. Summary of the invention
[0003] This problem is to be solved by the present invention.
[0004] The invention relates to a microfluidic interactive element for generating and / or detecting a volume flow of a fluid, wherein the microfluidic interactive element comprises a substrate having a cavity, wherein the cavity has at least one vertically arranged, rigid wall element, which is connected to the top and bottom of the cavity, and wherein a movable extrusion element having a vertical surface is also arranged in the cavity, so that the direction of movement of the extrusion element is substantially perpendicular to the main extension plane of the wall element, wherein the extrusion element laterally surrounds the corresponding wall element with its vertical surface, so that a first subspace and a second subspace are formed in the extrusion element by the wall element, respectively, wherein the microfluidic interactive element has a first penetration from the first subspace to the upper side of the substrate and a second penetration from the second subspace to the lower side of the substrate. Advantageously, the microfluidic interactive element can achieve a very high conversion efficiency from electrical energy to acoustic energy, so that a correspondingly high sound pressure level can be achieved by the extrusion element being able to be put into motion by an actuator element accordingly. Another advantage is that the interactive element is solderable, because there is no integrated magnet, has a low delay time due to its low mass and can also be constructed very small. Furthermore, the interactive element is very robust and due to the corresponding one-piece configuration of the extrusion element, all vertical faces of the extrusion element can be moved synchronously, which enables higher sound levels to be achieved. The vertical orientation of the faces of the extrusion element in conjunction with the vertically arranged wall elements can also increase the extruded volume per unit area, which in turn can be equated to an increased sound pressure level per unit area.
[0005] The microfluidic interaction element can be designed, for example, as a so-called MEMS element. A MEMS element is understood to be a microelectromechanical system which combines or integrates electronic and mechanical components, in particular in a minimal space.
[0006] By the horizontal movement of the extrusion element towards the rigid wall element, the partial volume on this side is compressed, while the partial volume on the side of the rigid wall is diluted (verdünnen) because the extrusion element moves away from the wall element there. Through the fluid opening on the substrate surface, the fluid can flow out from the compressed partial volume into the surrounding environment, while through another fluid opening on the opposite substrate surface, the fluid flows into the diluted partial volume from the surrounding environment. In this way, a net volume flow of the fluid of the surrounding environment in a direction perpendicular to the main extension plane of the substrate is generated by the MEMS element. If the extrusion element moves in the opposite direction, the opposite flow direction of the fluid is generated. In other words, sound waves with a positive pressure half wave and a negative pressure half wave can be generated in the fluid with the help of the interactive element. Depending on the configuration of the wall element, the main extension plane of the wall element can also be slightly inclined relative to the movement direction of the extrusion element.
[0007] In physics, the term "fluid" covers liquids and gases. A gas can be, for example, ordinary air, which moves with the aid of an interaction element and thereby generates a volume flow accordingly. A volume flow can therefore be understood as the movement of a fluid. When converted into a corresponding vibration movement, this volume flow can generate a sound pressure level that can be perceived, for example, by the human ear.
[0008] The substrate can be understood, for example, as a silicon substrate, which is used as a wafer substrate. The substrate is processed accordingly by process technology in order to produce the microfluidic interaction element therefrom. Thus, a groove is processed into the substrate, which forms a cavity with a corresponding through-hole between the cavity and the outside of the substrate. The groove in turn defines the interaction volume of the interaction element and is separated from the surroundings by the substrate.
[0009] In particular, it is conceivable that the interaction element has a plurality of wall elements, which are respectively surrounded by the extrusion element. The wall elements are planarly constructed, arranged vertically and, together with the vertical surface of the extrusion element, form corresponding first and second subspaces in the space surrounded by the extrusion element. Here, the extrusion element is arranged movably relative to the wall element along a horizontal movement direction oriented perpendicular to the main extension plane of the wall element. By the movement of the extrusion element, for example, negative pressure can be generated in the corresponding first subspace and overpressure can be generated in the second subspace.
[0010] A penetration is to be understood as an opening in the substrate which in each case connects a subspace formed in the cavity to the surroundings of the substrate.
[0011] The configuration of the invention provides that the extrusion element is connected to the substrate via a particularly elastic suspension device. Advantageously, the movability of the extrusion element can be ensured by the suspension device. The elastic configuration can also reduce the force consumption for moving the extrusion element, because the extrusion element returns to the initial position autonomously when biased.
[0012] A suspension device is understood to be an element by which the extrusion element is fixed to the substrate.
[0013] One embodiment of the invention provides that the suspension device is connected to the wall of the cavity. Advantageously, this constitutes a simple and robust possibility for suspending the extrusion element laterally in the cavity. It is conceivable that the suspension device can be arranged on the wall transversely to the direction of movement of the extrusion element and / or arranged on the wall along the direction of movement of the extrusion element.
[0014] Another configuration of the present invention provides that the suspension device is connected to the top and bottom of the cavity. Advantageously, this suspension mode has a small lateral space requirement, which can reduce the bottom surface of the microfluidic interaction element or keep it small.
[0015] In this case, the suspension device is of cylindrical design and extends from the bottom of the cavity to its top.
[0016] According to the configuration of the invention, the suspension device is laterally surrounded by the extrusion element. Advantageously, this constitutes a simple possibility for realizing vertical suspension. Such a suspension device is particularly robust.
[0017] According to another embodiment of the invention, the suspension device is vertically integrated into the extrusion element. Advantageously, the space requirement for the suspension device can be further reduced, so that the microfluidic interaction element itself can be made smaller.
[0018] Integrated in this case is to be understood to mean that the suspension device forms part of the extrusion element.
[0019] According to another embodiment of the invention, the microfluidic interaction element comprises an actuator region with an actuator element, which is configured to drive the extrusion element along the direction of movement, wherein the actuator element is in particular configured as an electrostatic drive and / or a piezoelectric drive. Advantageously, such an actuator element can drive the extrusion element uniformly, thereby achieving a synchronous movement of all vertical surfaces of the extrusion element, in order to optimize the generation of the sound pressure level.
[0020] Electrostatic drives can be designed, for example, as comb drives or nanoelectrostatic drives (NEDs). Furthermore, such actuator elements can be arranged directly on the suspension or integrated into the suspension, or can also be designed as separate structures. In piezoelectric drives, it is useful to arrange the drive element directly on the suspension or also on the extrusion element itself in order to be able to effect a direct force transmission from the actuator element to the suspension and thus to the extrusion element or directly to the extrusion element. Electrical contacting of the actuator element is then achieved, for example, by means of corresponding structuring in or on the suspension.
[0021] In particular, the wall element can also be designed to be electrically insulated from the extrusion element, wherein electrostatic forces can be generated by applying a voltage between the wall element and the extrusion element, since the wall element and the extrusion element act as electrodes and accordingly attract or repel each other.
[0022] In principle, it is also conceivable that the externally driven volume flow of the fluid as an external sound pressure level sets the interaction element or more precisely the extrusion element into motion. This can be detected by the actuator element as a sensor element using the reverse actuator principle. Thus, the volume flow of the fluid can also be detected accordingly.
[0023] According to another embodiment of the invention, the width of the first penetration and / or the second penetration is respectively less than 200 μm, in particular less than 100 μm, and the length is greater than 100 μm, in particular greater than 500 μm. Advantageously, there is a low fluid resistance between the subspace and the surroundings of the interactive element, thereby enabling a simple volume flow of the fluid. This is important for the acoustic properties of the interactive element and in turn enables high sound pressure levels.
[0024] The width is defined here along the direction of movement of the extrusion element, while the length is defined horizontally and transversely to the direction of movement of the extrusion element.
[0025] According to another embodiment of the invention, the distance between the wall element and the extrusion element is less than 20 μm, in particular less than 10 μm, at both ends of the wall element. Advantageously, there is a high fluid resistance between the subspaces, which can reduce fluid leakage due to the gap that necessarily exists between the extrusion element and the wall element. This makes it possible to achieve high sound pressure levels at low frequencies.
[0026] In this case, distance is to be understood as meaning the distance between the wall element and the extrusion element transversely to the direction of movement of the extrusion element.
[0027] According to another embodiment of the invention, the wall element has at least one transverse section perpendicular to the main extension plane of the wall element at least on one end side, in particular on both end sides. Advantageously, the fluid resistance between the subspaces is further increased and fluid leakage due to the gap between the wall element and the extrusion element can thus be reduced accordingly. Another advantage is that the at least one transverse section can be used as a mechanical stop or can also be used to dampen the movement of the extrusion element in an undesirable direction or with an undesirably large movement amplitude.
[0028] According to another embodiment of the invention, the vertical distance between the extrusion element and the bottom of the cavity and / or between the extrusion element and the top of the cavity is less than 5 μm, in particular less than 2 μm. Advantageously, there is a high fluid resistance between the subspaces, which can reduce fluid leakage due to the gap that necessarily exists between the cavity top or bottom and the extrusion element. This in turn makes it possible to achieve high sound pressure levels at low frequencies.
[0029] According to another embodiment of the invention, the wall element is wavy and / or bent. Advantageously, an increase in the filling factor of the interactive element can be achieved, thereby achieving a higher sound pressure level at the same bottom surface of the interactive element or achieving the same sound pressure level at a smaller bottom surface of the interactive element.
[0030] A wall element may be understood to be wavy or bent, which, in a plan view, has, for example, a wavy shape or can also be designed in a meandering manner.
[0031] The invention furthermore relates to an acoustic device, in particular a loudspeaker and / or a microphone, having at least one microfluidic interaction element according to the invention.
[0032] A loudspeaker can be understood as an acoustic converter that generates sound from an electrical input signal. A microphone can in turn convert sound into an electrical output signal. Here, the sound can be generated or detected by a corresponding interactive element. In the case of a plurality of interactive elements in a MEMS structural element, these interactive elements can differ from one another in their lateral dimensions and form, for example, a matrix assembly. The control or evaluation of the interactive elements can be achieved via a common or individually constructed control circuit. In particular, the control is carried out in such a way that, in order to produce an optimal sound pressure level, a synchronous biasing of the extrusion elements for all interactive elements can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1a A cross-sectional view as a top view shows a first embodiment of a microfluidic interaction element according to the present invention.
[0034] Figure 1b Show according to Figure 1a A side cross-sectional view of a first embodiment of a microfluidic interaction element according to the present invention.
[0035] Figure 2 A cross-sectional view as a top view shows a second embodiment of a microfluidic interaction element according to the present invention.
[0036] Figure 3 A cross-sectional view as a top view shows a third embodiment of the microfluidic interaction element according to the present invention.
[0037] Figure 4 A cross-sectional view as a top view shows a fourth embodiment of the microfluidic interaction element according to the present invention.
[0038] Figure 5 A cross-sectional view as a top view shows a fifth embodiment of the microfluidic interaction element according to the present invention.
[0039] Figure 6 An acoustic device having a plurality of microfluidic interaction elements according to the present invention is shown. DETAILED DESCRIPTION
[0040] Figure 1a A cross-sectional view as a top view of a first embodiment of a microfluidic interaction element according to the present invention is shown. A microfluidic interaction element 10 for generating a volume flow of a fluid not shown is shown, the microfluidic interaction element being cut along a section plane B and shown in a top view. The exact position of the section plane B is shown in FIG. Figure 1b Can be seen in.
[0041] The microfluidic interactive element 10 has a substrate 20 with a cavity 30 .
[0042] The cavity 30 here has three vertically arranged rigid wall elements 40 which are fixedly connected to the top 31 and the bottom 32 of the cavity 30 .
[0043] Furthermore, a movable extrusion element 50 having a vertical surface 51 is arranged in the cavity 30 , so that the movement direction x of the extrusion element 50 is essentially perpendicular to the main extension plane of the wall element 40 .
[0044] The extrusion element 50 surrounds the corresponding wall element 40 laterally with its vertical surface 51, so that a first subspace 41 and a second subspace 42 are formed in the extrusion element 50 by each wall element 40. Here, the distance d between the corresponding wall element 40 and the extrusion element 50 is less than 20 μm, in particular less than 10 μm, on both end sides 45 of the wall element 40.
[0045] Furthermore, the wall elements 40 each have a transverse section at both end sides 45 , which is perpendicular to the main extension plane of the wall element 40 .
[0046] In addition, the microfluidic interaction element 10 has a first through-portion 61 from the first subspace 41 to the upper side 21 of the substrate 20 and a second through-portion 62 from the second subspace 42 to the lower side 22 of the substrate 20, which is particularly Figure 1b This is again more clearly shown in . The first aperture 61 and / or the second aperture 62 can each have a width of less than 200 μm, in particular less than 100 μm, and a length of more than 100 μm, in particular more than 500 μm.
[0047] The extrusion element 50 is connected to the substrate 20 via a particularly elastic suspension device 70. The suspension device 70 is connected to the wall 33 of the cavity 30, wherein the suspension device 70 is designed as a crossbeam which is oriented transversely to the movement direction x of the extrusion element 50 and is arranged on both sides of the extrusion element 50 and is respectively connected to the extrusion element 50 in the middle.
[0048] Furthermore, the microfluidic interaction element 10 has an actuator region 80 , each of which has an actuator element that drives the extrusion element 50 along the movement direction x. The actuator element can be configured, for example, as an electrostatic drive and / or a piezoelectric drive. Here, the actuator element can be arranged on the suspension device 70 .
[0049] If the extrusion element 50 is moved to the right, for example, by means of an actuator element, the volume in the first subspace 41 is compressed, and accordingly, the volume in the second subspace 42 increases. Through the first penetration 61, the fluid can flow out from the compressed first subspace 41 into the surroundings of the interactive element 10, while through the second penetration 62 on the opposite substrate surface, the fluid flows from the surroundings into the diluted second subspace 42. In this way, a net volume flow of the fluid from the surroundings in a direction perpendicular to the main extension plane of the substrate 20 is generated. If the extrusion element 50 moves in the opposite direction, an opposite flow direction of the fluid is generated. In other words, an acoustic wave having a positive pressure half-wave and a negative pressure half-wave can be generated in the fluid by means of the interactive element 10.
[0050] Figure 1b Show according to Figure 1a A side cross-sectional view of a first embodiment of a microfluidic interaction element according to the present invention.
[0051] It also shows Figure 1a The interactive element 10, but this time along the Figure 1a A lateral cross section of the section plane A shown in FIG.
[0052] Here again, a substrate 20 is shown with a cavity 30, in which a rigid wall element 40 and an extrusion element 50 movable in a movement direction x with its vertical surface 51 are arranged. Furthermore, a first subspace 41 and a second subspace 42 formed by the corresponding configuration and arrangement of the wall element 40 and the extrusion element 50 can be seen, which each have a first penetration 61 to the upper side 21 of the substrate 20 and a second penetration 62 to the lower side 22 of the substrate 20.
[0053] The vertical distance h between the extrusion element 50 and the bottom 32 of the cavity 30 and / or between the extrusion element 50 and the top 31 of the cavity 30 is less than 5 μm, in particular less than 2 μm.
[0054] As in Figure 1a As described in , if the extrusion element 50 is moved to the right, for example, by the actuator element, this generates a fluid volume flow from bottom to top relative to the substrate 20. If the extrusion element 50 is moved in the opposite direction, an opposite flow direction of the fluid is generated. In other words, with the help of the interaction element 10, sound waves with a positive pressure half-wave and a negative pressure half-wave can be generated in the fluid, which should be indicated by corresponding double arrows.
[0055] Figure 2 A cross-sectional view as a top view of a second embodiment of a microfluidic interaction element according to the present invention is shown. The microfluidic interaction element 110 is shown, which is connected to the suspension device 170 only in the configuration of the suspension device 170. Figure 1aThe interaction element 10 is different. Thus, in this case, the suspension device 170 has a longitudinal beam which is connected to the wall 33 of the cavity 30 in a longitudinal direction relative to the direction of movement x of the extrusion element 50 .
[0056] Figure 3 FIG. 2 shows a cross-sectional view as a top view of a third embodiment of a microfluidic interaction element according to the present invention. FIG. 2 shows a microfluidic interaction element 210, which is again connected to the suspension device 170 in the configuration of the suspension device 170. Figure 1a The suspension device 270 is arranged in the middle and is cylindrically configured and is connected to the top 31 and the bottom 32 of the cavity 30 (not shown) and is also surrounded laterally by the extrusion element 50. Figure 1a Compared to the interaction element 10 of the embodiment of the present invention, the suspension device 270 is arranged to almost replace the central wall element 40. The centrally arranged cylindrical configuration of the suspension device 270 is connected to the extrusion element 50 via corresponding springs, on which the actuator region 80 is arranged.
[0057] Figure 4 A cross-sectional view as a top view of a fourth embodiment of a microfluidic interaction element according to the present invention is shown. A microfluidic interaction element 310 is shown, which is again connected to the suspension device 170 in the configuration of the suspension device 170. Figure 1a The interactive element 10 is different. The suspension device 370 is different from Figure 3 The suspension device 270 in the embodiment is cylindrically configured and connected to the top 31 and the bottom 32 of the cavity 30 (this is not shown), wherein the suspension device 270 is cylindrically configured and connected to the top 31 and the bottom 32 of the cavity 30 (this is not shown in the figure), wherein Figure 3 In contrast to the suspension device 270 of , the suspension device 370 is vertically integrated into the extrusion element 50 . In this case, the actuator region 80 with the actuator element is arranged directly on the extrusion element 50 , for example as a piezoelectric layer.
[0058] Figure 5 FIG. 4 is a cross-sectional view as a top view of a fifth embodiment of a microfluidic interaction element according to the present invention. FIG. 4 shows a microfluidic interaction element 410, which is connected to a wall element 440 in a configuration. Figure 1a The wall element 440 is therefore configured to be bent, thereby Figure 1a Instead of only three wall elements 40, four wall elements 440 can be arranged on the same bottom surface of the interaction element 10. The wall elements 440 again have transverse sections on their end sides 445, wherein the transverse distance d between the end sides 445 of the wall elements 440 and the extrusion element 50 is respectively less than 20 μm, in particular less than 10 μm.
[0059] Figure 6An acoustic device having a plurality of microfluidic interaction elements according to the present invention is shown. An acoustic device 500 is shown, which can be configured as a loudspeaker and / or a microphone, for example. The acoustic device 500 has a plurality of microfluidic interaction elements 10, 110, 210, 310, 410, which are arranged adjacent to each other in a plane. With the aid of these microfluidic interaction elements 10, 110, 210, 310, 410, a loudspeaker can generate a corresponding sound pressure level. Here, the interaction elements 10, 110, 210, 310, 410 can differ from each other in their lateral dimensions and form, for example, a matrix assembly. The control of the interaction elements 10, 110, 210, 310, 410 can then be achieved by a common or individually constructed (not shown) control circuit.
Claims
1. A microfluidic interaction element (10, 110, 210, 310, 410) for generating and / or detecting a volume flow of a fluid, wherein: The microfluidic interaction element (10, 110, 210, 310, 410) has a substrate (20) having a cavity (30), wherein the cavity (30) has at least one vertically arranged, rigid wall element (40, 440), the wall element being connected to the top (31) and the bottom (32) of the cavity (30), and wherein a movable extrusion element (50) having a vertical surface (51) is also arranged in the cavity (30), so that the movement direction (x) of the extrusion element (50) is substantially perpendicular to the main extension plane of the wall element (40, 440), wherein In the embodiment of the present invention, the extrusion element (50) laterally surrounds the corresponding wall element (40, 440) with its vertical surface (51), so that a first subspace (41) and a second subspace (42) are respectively formed in the extrusion element (50) through the wall elements (40, 440), wherein the microfluidic interaction element (10, 110, 210, 310, 410) respectively has a first penetration portion (61) from the first subspace (41) to the upper side (21) of the substrate (20) and a second penetration portion (62) from the second subspace (42) to the lower side (22) of the substrate (20).
2. The microfluidic interaction element (10, 110, 210, 310, 410) according to claim 1, characterized in that: The extrusion element (50) is connected to the substrate (20) via a suspension device (70, 170, 270, 370), in particular an elastic suspension device.
3. The microfluidic interaction element (10, 110, 410) according to claim 2, characterized in that: The suspension device (70, 170) is connected to the wall (33) of the cavity (30).
4. The microfluidic interaction element (210, 310, 410) according to claim 2, characterized in that: The suspension device (270, 370) is connected to the top (31) and the bottom (32) of the cavity (30).
5. The microfluidic interaction element (210, 410) according to claim 4, characterized in that: The suspension device (270) is laterally surrounded by the extrusion element (50).
6. The microfluidic interaction element (310, 410) according to claim 4, characterized in that: The suspension device (370) is vertically integrated into the extrusion element (50).
7. The microfluidic interaction element (10, 110, 210, 310, 410) according to any one of the preceding claims, characterized in that: The microfluidic interaction element (10, 110, 210, 310, 410) comprises an actuator region (80) having an actuator element, which drives the extrusion element (50) along the movement direction (x), wherein the actuator element is in particular configured as an electrostatic drive and / or a piezoelectric drive.
8. The microfluidic interaction element (10, 110, 210, 310, 410) according to any one of the preceding claims, characterized in that: The width of the first penetration (61) and / or the second penetration (62) is respectively less than 200 μm, in particular less than 100 μm, and the length is greater than 100 μm, in particular greater than 500 μm.
9. The microfluidic interaction element (10, 110, 210, 310, 410) according to any one of the preceding claims, characterized in that: The distance (d) between the wall element (40, 440) and the extrusion element (50) is less than 20 μm, in particular less than 10 μm, at both end sides (45, 445) of the wall element (40, 440).
10. The microfluidic interaction element (10, 110, 210, 310, 410) according to any one of the preceding claims, characterized in that: The wall element (40, 440) has at least one transverse section perpendicular to a main extension plane of the wall element (40, 440) at least on one end side (45, 445), in particular on both end sides (45, 445).
11. The microfluidic interaction element (10, 110, 210, 310, 410) according to any one of the preceding claims, characterized in that: A vertical distance (h) between the extrusion element (50) and the bottom (32) of the cavity (30) and / or between the extrusion element (50) and the top (31) of the cavity (30) is less than 5 μm, in particular less than 2 μm.
12. The microfluidic interaction element (410) according to any one of the preceding claims, characterized in that: The wall element (440) is embodied in a corrugated and / or angled manner.
13. An acoustic device (500), in particular a loudspeaker and / or a microphone, having at least one microfluidic interaction element (10, 110, 210, 310, 410) according to any of the preceding claims.