A fluidic device having asymmetric orifices

Abstract

The utility model provides a kind of microfluidic device with asymmetric nozzle, belong to microfluidic device technical field.Microfluidic device includes MEMS actuator and base orifice plate.Base orifice plate and MEMS actuator surround micro-nano cavity, base orifice plate has nozzle, nozzle penetrates base orifice plate along the thickness direction of base orifice plate, the size of nozzle close to the first end of micro-nano cavity is greater than the size of nozzle away from the second end of micro-nano cavity, the side wall of opposite side of nozzle along preset direction is respectively first side wall and second side wall, preset direction is arranged across the thickness direction of base orifice plate, the included angle of first side wall and preset direction is first included angle, the included angle of second side wall and preset direction is second included angle, first included angle is not equal to second included angle, MEMS actuator can vibrate, to make fluid in micro-nano cavity be ejected by nozzle.The microfluidic device of the utility model can improve the heat dissipation efficiency of electronic equipment.

Description

Technical Field

[0001] This utility model relates to the field of micro jet ejector technology, and in particular to a jet ejector with an asymmetric nozzle. Background Technology

[0002] Electronic devices are rapidly evolving towards miniaturization, high integration, and high power density. Controlling airflow direction at the microscale is common in fields such as microelectromechanical systems (MEMS) and chip-level heat dissipation in electronic devices, placing higher demands on the precision, uniformity, and structural compatibility of airflow direction control in micro-nozzles. Related micro-airflow control technologies mainly involve traditional symmetrical nozzles with external deflection devices. The core of this technology is a simple symmetrical nozzle (such as a circular, rectangular, or conical silicon etched channel), but an additional micro-actuator is integrated downstream of its outlet to deflect the airflow. For the nozzle itself, isotropic or anisotropic wet or dry etching is typically used to create a straight channel on a silicon wafer or glass, which suffers from problems such as unidirectional airflow, insufficient directionality, and weak adaptability to multiple heat sources. Common deflection actuators include: 1. Micro piezoelectric cantilever beams, which bend when energized to physically block and guide airflow; 2. Micro thermal actuators, which use thermal expansion to drive the deflection of a micro baffle; 3. Electrostatic drive mechanisms, which use electrostatic force to drive a micro guide vane into the flow field. The aforementioned deflection actuators all suffer from problems such as overly complex structure, low reliability, and high cost. Utility Model Content

[0003] This invention provides a jet generator with an asymmetric nozzle, the purpose of which is to utilize the changes in the inherent pressure field and velocity field generated when the airflow passes through the nozzle to achieve directional deflection of the airflow and improve the heat dissipation efficiency of the synthetic jet inside compact electronic devices.

[0004] To achieve the above objectives, this utility model provides a jet injector with an asymmetric nozzle, comprising:

[0005] MEMS actuators;

[0006] A substrate aperture plate, together with the MEMS actuator, encloses a micro / nano cavity. The substrate aperture plate has a nozzle that penetrates the substrate aperture plate along its thickness direction. The size of the first end of the nozzle near the micro / nano cavity is larger than the size of the second end of the nozzle away from the micro / nano cavity. The sidewalls on opposite sides of the nozzle along a predetermined direction are a first sidewall and a second sidewall, respectively. The predetermined direction is intersected with the thickness direction of the substrate aperture plate. The angle between the first sidewall and the predetermined direction is a first angle, and the angle between the second sidewall and the predetermined direction is a second angle. The first angle is not equal to the second angle. The MEMS actuator can vibrate to eject fluid from the micro / nano cavity through the nozzle.

[0007] In one embodiment, the first included angle ranges from 30° to 90°, and the second included angle ranges from 15° to 45°.

[0008] In one embodiment, the roughness of the first sidewall surface is not equal to the roughness of the second sidewall surface.

[0009] In one embodiment, the roughness of the first sidewall surface is less than or equal to 0.08 μm, and the roughness of the second sidewall surface is less than or equal to 0.12 μm.

[0010] In one embodiment, the substrate plate is configured to be made of a silicon-based material.

[0011] In one embodiment, the number of nozzles is multiple.

[0012] In one embodiment, the plurality of nozzles are arranged in an array.

[0013] The above-mentioned solution of this utility model has the following beneficial effects:

[0014] In this embodiment, by changing the shape of the nozzle itself and setting the angles of the first and second included angles to be unequal, the nozzle is arranged in an asymmetrical manner. This asymmetrical arrangement forces the fluid to generate a non-uniform pressure distribution during acceleration within the nozzle, resulting in inherent changes in the pressure and velocity fields as the fluid passes through it. This achieves directional deflection of the airflow without the need for an additional deflection actuator. The directional deflection of the fluid can be achieved by adjusting the angles of the first and second included angles. The deflected fluid can then directly blow onto heat-generating components located elsewhere, improving heat dissipation efficiency within compact electronic devices. Furthermore, since the base plate is a lightweight, single component, its service life depends solely on material aging, without considering the fatigue life of the baffles controlling the airflow direction in the deflection actuator. This not only makes the ejector of this application highly reliable but also simplifies its structure and eliminates the need to consume energy to drive the deflection actuator. Aerodynamic efficiency is also significantly improved when there is no obstruction from the deflection actuator. By eliminating the need to integrate deflection actuators into the jet injector, the number of photolithographic mask layers is reduced, thereby decreasing the number of process steps and packaging complexity. This improves the yield rate and lowers the production cost of the jet injector. In summary, this application achieves the desired technical effect by modifying the jet injector's architecture and utilizing the geometric complexity of the nozzle to replace the system complexity of the jet injector.

[0015] Other beneficial effects of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of an ejector with an asymmetric nozzle in one embodiment of the present invention;

[0017] Figure 2 This is a three-dimensional structural diagram of the nozzle in one embodiment of the present invention;

[0018] Figure 3 This is a schematic diagram simulating the flow field when the second included angle is different in one embodiment of this utility model. Figure 3 (a) shows the airflow direction when the first included angle is 90° and the second included angle is 15°. Figure 3 (b) shows the airflow direction when the first included angle is 90° and the second included angle is 30°. Figure 3 (c) shows the airflow direction when the first included angle is 90° and the second included angle is 45°.

[0019] Figure 4 This is a schematic diagram of the flow field simulation of a symmetrical nozzle in related technologies. The diagram shows the airflow direction when the included angle between the left and right sidewalls of the nozzle is the same.

[0020] [Explanation of Labels in the Attached Image]

[0021] 1. MEMS actuator; 2. Substrate perforated plate; 21. Nozzle; 211. First sidewall; 212. Second sidewall; 12. Micro / nano cavity; 3. Silicon substrate; 4. Glass; 5. PCB board. Detailed Implementation

[0022] To make the technical problems, solutions, and advantages of this utility model clearer, a detailed description will be provided below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0023] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a locking connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0025] In related technologies, structures for controlling airflow direction have the following problems:

[0026] Symmetrical nozzles exhibit a single airflow direction and insufficient directionality: due to the left-right symmetry of the nozzle sidewalls, the typical diffusion angle is 30°~45°. (See also...) Figure 4 The airflow inside the nozzle flows in a straight line along the nozzle axis, and the outlet airflow direction is fixed to the nozzle axis direction, which makes it impossible to cool the local high-heat areas of electronic devices.

[0027] Weak adaptability to multiple heat sources: Multiple heat sources (such as processors and charging chips) are distributed in a dispersed manner and emit different amounts of heat. Symmetrical nozzles cannot achieve differentiated heat dissipation for different heat sources through a single structure.

[0028] Complex structure and low reliability: Due to the introduction of moving parts (such as cantilever beams, baffles, etc.), fatigue failure and material creep are easily caused by vibration and thermal effects induced by high-speed airflow.

[0029] Low energy efficiency: The actuator, i.e. the moving part, requires additional energy to work (such as driving piezoelectric devices, heating resistors, etc.), and its physical structure can significantly obstruct the mainstream airflow, introducing unnecessary pressure drop and turbulence, resulting in large energy loss.

[0030] Complex manufacturing process and high cost: The integration of micro actuators greatly increases the number of layers in the photolithography mask, the number of process steps and the difficulty of packaging, resulting in a decrease in yield and a sharp increase in cost.

[0031] Therefore, existing technical solutions merely treat the nozzle as a flow outlet, rather than as a functional component capable of actively shaping the flow field using microscopic phenomena such as viscous forces and pressure gradients. This underscores the importance of asymmetric nozzle structures. By designing an asymmetric nozzle structure, the limitations of symmetrical structures are overcome, enabling active optimization of airflow direction and meeting the heat dissipation requirements of compact, miniaturized electronic devices.

[0032] In view of this, in order to address the drawback of the single airflow direction of symmetrical nozzles, this application provides a jetting device with an asymmetrical nozzle. By utilizing the fixed asymmetrical geometry of the internal flow channel of the nozzle, the inherent pressure field and velocity field generated when the airflow passes through this shape are utilized to achieve directional deflection of the airflow, thereby improving the heat dissipation efficiency of the synthetic jet inside compact electronic devices.

[0033] Specifically, please refer to Figure 1 and Figure 2 This application provides an ejector with an asymmetric nozzle 21, including a MEMS actuator 1 and a base plate 2.

[0034] MEMS (Micro-Electro-Mechanical System) actuator 1 refers to an actuator with a size of a few millimeters or even smaller. MEMS actuator 1 can convert electrical signals into micro-motions or micro-operations to generate vibrations.

[0035] A substrate aperture plate 2 and a MEMS actuator 1 enclose a micro / nano cavity 12. The substrate aperture plate 2 has a nozzle 21. The nozzle 21 penetrates the substrate aperture plate 2 along its thickness direction, allowing it to communicate with both the micro / nano cavity 12 and the outside environment. The size of the first end of the nozzle 21 near the micro / nano cavity 12 is larger than the size of the second end of the nozzle 21 away from the micro / nano cavity 12, making the nozzle 21 generally conical or frustum-shaped. The sidewalls of the nozzle 21 on opposite sides along a predetermined direction are a first sidewall 211 and a second sidewall 212, respectively. The predetermined direction is intersected with the thickness direction of the substrate aperture plate 2, for example, it can be perpendicular to it. For example, the predetermined direction can be the extension direction of the substrate aperture plate 2. The angle between the first sidewall 211 and the predetermined direction is a first angle, and the angle between the second sidewall 212 and the predetermined direction is a second angle. For example, please refer to... Figure 1 , Figure 1 In the diagram, θ1 represents the first included angle, and θ2 represents the second included angle. The first included angle is not equal to the second included angle, so that the shape of the nozzle 21 is asymmetrically arranged. When the MEMS actuator 1 vibrates at a preset frequency, the fluid inside the micro-nano cavity 12 is ejected through the nozzle 21. The fluid ejected through the nozzle 21 can dissipate heat from heat-generating components located in the external environment. It should be noted that the external environment refers to the space outside the micro-nano cavity 12, and the external environment may still be located within the electronic device including the ejector of this application.

[0036] In this embodiment, by changing the shape of the nozzle 21 itself, the angles of the first and second included angles are set to be unequal, so that the nozzle 21 is arranged asymmetrically. The asymmetrical arrangement of the nozzle 21 forces the fluid to generate a non-uniform pressure distribution during acceleration within the nozzle 21, causing changes in the inherent pressure and velocity fields as the fluid passes through the nozzle 21. This achieves directional deflection of the airflow without the need for an additional deflection actuator. The directional deflection of the fluid can be achieved by adjusting the angles of the first and second included angles. The deflected fluid can directly blow onto heat-generating elements located in other positions, which is beneficial for improving heat dissipation efficiency within compact electronic devices. Furthermore, since the base plate 2 is a lightweight, single component, its service life depends only on material aging, without considering the fatigue life of the baffle controlling the airflow direction in the deflection actuator. This not only makes the ejector of this application highly reliable but also simplifies its structure and eliminates the need to consume energy to drive the deflection actuator. Aerodynamic efficiency is also significantly improved when there is no obstruction from the deflection actuator. By eliminating the need to integrate deflection actuators into the jet injector, the number of photolithography mask layers is reduced, thereby decreasing the number of process steps and packaging complexity. This improves the yield rate and lowers the production cost of the jet injector. In summary, this application achieves the desired technical effect by modifying the jet injector's architecture and utilizing the geometric complexity of the nozzle 21 to replace the system complexity of the jet injector.

[0037] In one embodiment, please refer to Figure 1 and Figure 3 The first included angle ranges from 30° to 90°, and the second included angle ranges from 15° to 45°. Figure 3 The diagram illustrates the airflow direction when the first included angle is 90° and the second included angle is at various angles. This forces the fluid to generate a non-uniform pressure distribution during acceleration within the nozzle 21, causing inherent changes in the pressure and velocity fields as the fluid passes through the nozzle 21. This achieves directional deflection of the airflow without the need for an additional deflection actuator. The deflected fluid can then directly blow onto heat-generating components located elsewhere, improving heat dissipation efficiency within compact electronic devices. Furthermore, by adjusting the relative sizes of the first and second included angles, the response frequency of the fluid within the nozzle 21 can be synchronized with the vibration frequency of the MEMS actuator 1 (typically 4kHz to 8kHz). For example, when the vibration frequency of the MEMS actuator 1 is 6.5 kHz, setting the first included angle to 40° and the second included angle to 20° can improve the continuity of fluid generation from the nozzle 21 by 20% to 50%.

[0038] In one embodiment, the roughness of the surface of the first sidewall 211 is not equal to the roughness of the surface of the second sidewall 212. The difference in roughness between the first sidewall 211 and the second sidewall 212 further optimizes the flow velocity distribution of the fluid, which is beneficial to reducing local eddy current losses of the fluid.

[0039] In one embodiment, the surface roughness of the first sidewall 211 is less than or equal to 0.08 μm, and the surface roughness of the second sidewall 212 is less than or equal to 0.12 μm, so that there is a difference in roughness between the first sidewall 211 and the second sidewall 212, in order to further optimize the flow velocity distribution of the fluid and help reduce local eddy current losses of the fluid.

[0040] In one embodiment, the substrate aperture plate 2 is configured to be made of silicon, enabling the nozzle 21 to be integrally formed with the micro / nano cavity 12 via a TSV (Through Silicon Via) process. For example, please refer to... Figure 1 A silicon substrate 3, glass 4, PCB (Printed Circuit Board) 5, and glass 4 can be stacked sequentially between the substrate hole plate 2 and the MEMS actuator 1. In the pre-processing stage of the silicon substrate 3, a patterned mask of the asymmetric nozzle 21 is formed by photolithography. The laser drilling path is adjusted according to the structural parameters of the left and right sides to ensure the accuracy of the asymmetric structure (dimensional error ≤ ±2μm).

[0041] In one embodiment, there are multiple nozzles 21, which can simultaneously eject fluid, so that the jet ejector of this application can simultaneously dissipate heat from multiple heat-generating elements, which is beneficial to improving the heat dissipation efficiency of the jet ejector.

[0042] In one embodiment, multiple nozzles 21 are arranged in an array. For example, an asymmetrical array arrangement such as 1×2 or 2×3 can be used. The spacing between adjacent nozzles 21 can be adjusted according to the distribution of the heating elements to achieve precise coverage of multiple heat sources. For example, the spacing between two adjacent nozzles 21 can range from 600 μm to 1200 μm.

[0043] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A jet ejector with an asymmetric nozzle, characterized in that, include: MEMS actuators; A substrate aperture plate, together with the MEMS actuator, encloses a micro / nano cavity. The substrate aperture plate has a nozzle that penetrates the substrate aperture plate along its thickness direction. The size of the first end of the nozzle near the micro / nano cavity is larger than the size of the second end of the nozzle away from the micro / nano cavity. The sidewalls on opposite sides of the nozzle along a predetermined direction are a first sidewall and a second sidewall, respectively. The predetermined direction is intersected with the thickness direction of the substrate aperture plate. The angle between the first sidewall and the predetermined direction is a first angle, and the angle between the second sidewall and the predetermined direction is a second angle. The first angle is not equal to the second angle. The MEMS actuator can vibrate to eject fluid from the micro / nano cavity through the nozzle.

2. The jet ejector with an asymmetric nozzle according to claim 1, characterized in that, The first included angle ranges from 30° to 90°, and the second included angle ranges from 15° to 45°.

3. The jet ejector with an asymmetric nozzle according to claim 1, characterized in that, The roughness of the first sidewall surface is not equal to the roughness of the second sidewall surface.

4. The jet ejector with an asymmetric nozzle according to claim 1, characterized in that, The roughness of the first sidewall surface is less than or equal to 0.08 μm, and the roughness of the second sidewall surface is less than or equal to 0.12 μm.

5. The jet ejector with an asymmetric nozzle according to claim 1, characterized in that, The substrate plate is made of silicon-based material.

6. The jet ejector with an asymmetric nozzle according to claim 1, characterized in that, The number of nozzles is multiple.

7. The jet ejector with an asymmetric nozzle according to claim 6, characterized in that, The multiple nozzles are arranged in an array.

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