Micropump

Abstract

The micropump comprises a silicon wafer, a first sealing piece and a second sealing piece, the silicon wafer is provided with a first face and a second face which are opposite to each other, a first groove used for forming a pump cavity is etched in the first face, and a plurality of grooves which meet the equal-width condition and are used for forming a moving body, an annular rib and a first valve body of an outlet valve are etched in the second face. The annular rib surrounds the moving body and is connected to a pump membrane around the moving body, and the first valve body is connected to a valve membrane of the outlet valve. The first sealing piece is fixed to the first face of the silicon wafer and covers the first groove to form a pump cavity. The second sealing sheet is fixed on the second surface of the silicon wafer. The second sealing sheet is provided with a connecting port used for connecting a driver at a position corresponding to the moving body. According to the micropump, through reasonable structural design, better etching uniformity can be obtained within shorter etching process time, the process cost is reduced, meanwhile, the product yield is improved, the situation that normal use in a low-temperature environment is affected due to the fact that much liquid is accumulated on the outlet valve is avoided, and the service life is prolonged.

Description

Technical Field

[0001] This invention relates to the field of microsystems technology, and in particular to a micropump. Background Technology

[0002] Micro-Electro-Mechanical Systems (MEMS), also known as micro-electromechanical systems, microsystems, or micromachines, refer to high-tech devices with dimensions of a few millimeters or even smaller. A micropump is an actuator designed and manufactured using MEMS technology, capable of fluid transport and control within a tiny scale. Its pumping accuracy and rate are ideally suited for the injection of sustained-release or micro-volume medications such as insulin, anesthetics, and analgesics.

[0003] Current micropumps suffer from the following drawbacks due to structural design deficiencies: The large size of individual micropumps limits the number of pumps that can be fabricated on the wafers used for manufacturing, resulting in low wafer utilization and high manufacturing costs; the difficulty in ensuring that trenches at different locations achieve roughly the same depth during silicon etching leads to low product yield; and the accumulation of liquid in the outlet valve cavity causes expansion and freezing when the pump is used in low-temperature environments (below 0°C), which can damage the outlet structure and cause pump failure. Therefore, it is necessary to improve micropumps to address at least one of these problems. Summary of the Invention

[0004] This invention provides the following technical solution:

[0005] A micropump, comprising:

[0006] A silicon wafer has a first side and a second side facing each other. The first side is etched with a first groove for forming a pump chamber. The second side is etched with a plurality of grooves that meet the condition of equal width for forming a moving body, an annular rib and a first valve body for forming an outlet valve. The annular rib surrounds the moving body and is connected to a pump diaphragm around the moving body. The first valve body is connected to the valve diaphragm of the outlet valve.

[0007] A first sealing sheet is fixed to the first side of the silicon wafer to seal the first groove and form a pump chamber.

[0008] The second sealing plate is fixed to the second side of the silicon wafer, and the second sealing plate has a connection port for connecting the driver at the position corresponding to the moving body.

[0009] Optionally, in the micropump described above, the silicon wafer has a first through hole at a position other than the first groove, the second surface is etched with a second groove for connecting the first through hole and the outlet valve, the first sealing plate has an outlet port communicating with the first through hole at the position corresponding to the first through hole, and the second sealing plate has an inlet port at the position corresponding to the inlet valve.

[0010] Optionally, in the micropump described above, the annular rib includes a plurality of discontinuous bodies spaced apart around the moving body, and the gaps between the discontinuous bodies and the grooves between the annular rib and the moving body satisfy the condition of equal width.

[0011] Optionally, in the above-mentioned micropump, the annular rib is a double-ring structure, including a first ring and a second ring arranged concentrically around the moving body, and the gap between the first ring and the second ring satisfies the same width condition as the groove between the annular rib and the moving body.

[0012] Optionally, in the above-mentioned micropump, the first valve body has a double-ring structure, including a third ring and a fourth ring arranged concentrically around the central flow channel of the outlet valve, wherein the gap between the third ring and the fourth ring and the groove between the annular rib and the moving body satisfy the condition of equal width.

[0013] Optionally, in the above-mentioned micropump, the annular rib is a lattice structure, comprising multiple circular or square columns distributed in a lattice.

[0014] Optionally, in the micropump described above, the first valve body has a dot matrix structure, comprising multiple circular or square columns distributed in a dot matrix.

[0015] Optionally, in the micropump described above, the first sealing sheet and / or the second sealing sheet are configured as glass sheets or silicon wafers.

[0016] The micropump provided by this invention has the following beneficial effects:

[0017] The first sealing plate covers the first groove on the first side of the silicon wafer to form the pump chamber. Multiple grooves are etched on the second side of the silicon wafer to form the moving body, annular ribs, and the first valve body of the outlet valve. The annular ribs surround the moving body and connect to the pump diaphragm around it. The first valve body connects to the valve diaphragm of the outlet valve. These grooves meet the condition of equal width, so when etching these grooves at different locations, the depth obtained at the same time is approximately the same, ensuring etching uniformity and thus improving the product yield of the micropump. Simultaneously, the first valve body is formed on the second side of the silicon wafer, which is the side of the outlet valve facing away from the pump chamber. The first valve body connects to the valve diaphragm of the outlet valve, filling part of the cavity of the traditional outlet valve. This avoids the outlet valve forming a large cavity and accumulating a large amount of liquid, thus reducing the risk of liquid freezing and expansion that could damage the outlet structure when the micropump is used in low-temperature environments (below 0°C), and improving the service life of the micropump. Moreover, compared with traditional micropumps, since the annular rib occupies part of the traditional cavity on the side of the pump diaphragm facing away from the pump chamber, and the first valve body occupies part of the traditional cavity on the side of the outlet valve diaphragm facing away from the pump chamber, the amount of material that needs to be etched away from the silicon wafer is reduced, which helps to shorten the etching process time and thus reduce the process cost. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 This is a three-dimensional schematic diagram of the micropump after longitudinal section provided in Embodiment 1 of the present invention;

[0020] Figure 2 yes Figure 1 AA section view in the middle;

[0021] Figure 3 This is a cross-sectional view of the micropump provided in Embodiment 1 of the present invention after longitudinal sectioning;

[0022] Figure 4 yes Figure 3 BB section view in the middle;

[0023] Figure 5 This is a partial schematic diagram of the cross-section of the micropump provided in Embodiment 2 of the present invention;

[0024] Figure 6 This is a schematic diagram of the first structural form of ring reinforcement;

[0025] Figure 7This is a schematic diagram of the second structural form of the ring reinforcement;

[0026] Figure 8 This is a schematic diagram of the third structural form of ring reinforcement;

[0027] Figure 9 This is a schematic diagram of the fourth structural form of ring reinforcement;

[0028] Figure 10 This is a schematic diagram of the fifth structural form of ring reinforcement;

[0029] Figure 11 This is a schematic diagram of the first structural form of the first valve body;

[0030] Figure 12 This is a schematic diagram of the second structural form of the first valve body;

[0031] Figure 13 This is a schematic diagram of the third structural form of the first valve body;

[0032] Figure 14 This is a schematic diagram of the fourth structural form of the first valve body;

[0033] Figure 15 This is a schematic diagram of the fifth structural form of the first valve body.

[0034] The diagram is marked as follows:

[0035] 1. First sealing wafer; 2. Silicon wafer; 3. Second sealing wafer;

[0036] 11. Liquid outlet;

[0037] 20. First groove; 21. Inlet valve; 22. Moving body; 23. Annular rib; 24. Pump diaphragm; 25. Central flow channel; 26. First valve body; 27. Valve diaphragm; 28. Second valve body; 29. ​​First through hole;

[0038] 31. First anti-bonding part; 32. Liquid inlet; 33. Connecting port; 34. Second anti-bonding part;

[0039] a. Inlet channel; b. Pump chamber; c. Connecting channel; d. Outlet channel. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] See Figures 1-4 Embodiment 1 of the present invention provides a micropump, including a silicon wafer 2, a first sealing plate 1, and a second sealing plate 3. The silicon wafer 2 has a first surface and a second surface facing each other. The first surface is etched with a first groove 20 for forming a pump chamber b. The second surface is etched with multiple grooves satisfying the condition of equal width for forming a moving body 22, an annular rib 23, and a first valve body 26 of an outlet valve. These grooves are distributed around the moving body 22, the annular rib 23, and the first valve body 26, and are spatial structures formed after etching away some material on the second surface of the silicon wafer 2. The equal width condition means that the widths of the grooves at different locations are equal or approximately equal; that is, although the positions of the grooves are different, their widths are generally consistent. Specifically, the annular rib 23 surrounds the moving body 22 and is connected to a pump diaphragm 24 around the moving body 22, and the first valve body 26 is connected to a valve diaphragm 27 of the outlet valve. The pump diaphragm 24, or the thin film portion between the moving body 22 and the surrounding fixed body, is used to achieve elastic deformation. The fixed body refers to the part of the silicon wafer 2 that remains stationary. This part is fixed together with the sealing plate by anodic bonding. The valve diaphragm 27, or the thin film portion between the second valve body 28 of the outlet valve and the surrounding fixed body, is used to achieve elastic deformation. The second valve body 28 is the valve body of the outlet valve located on the pump chamber b side. The first sealing plate 1, the silicon wafer 2, and the second sealing plate 3 are stacked. The first sealing plate 1 is fixed to the first surface of the silicon wafer 2, sealing the first groove 20 to form the pump chamber b. The second sealing plate 3 is fixed to the second surface of the silicon wafer 2, and the second sealing plate 3 has a connection port 33 for connecting the driver (not shown in the figure) at the position corresponding to the moving body 22. The driver is the power source of the micropump. The driver drives the moving body 22 of the micropump to reciprocate, realizing the pressure change of the pump chamber b, and is connected to the inlet valve 21 and the outlet valve to guide the liquid flow.

[0042] It should be noted that in the etching process of silicon wafer 2, the depth of the etched trench refers to the dimension in the thickness direction of silicon wafer 2, and the width of the trench is the dimension in the direction perpendicular to the thickness direction of silicon wafer 2. The annular rib 23 is connected to the pump diaphragm 24 surrounding the moving body 22 and can move with the pump diaphragm 24. Similarly, the first valve body 26 of the outlet valve is connected to the valve diaphragm 27 surrounding the second valve body 28 and can move with the valve diaphragm 27. Because the trenches forming the moving body 22, the annular rib 23, and the first valve body 26 of the outlet valve satisfy the condition of equal width, the uniformity of etching is easily guaranteed. That is, when etching these trenches at different locations, the depth obtained in the same time is approximately the same, which is beneficial to improving the product yield of the micropump. Furthermore, the second valve body 28 of the outlet valve, located on the pump chamber b side, functions as a switch, while the first valve body 26, positioned on the other side of the outlet valve, fills a portion of the cavity of the traditional outlet valve. This prevents the outlet valve from forming a large cavity and accumulating excessive liquid, thus reducing the risk of liquid freezing and expansion that could damage the outlet structure when the micropump is used in low-temperature environments (below 0°C), and improving the lifespan of the micropump. Moreover, compared to traditional micropumps, because the annular rib 23 occupies a portion of the traditional cavity on the side of the pump diaphragm 24 facing away from pump chamber b, and the first valve body 26 occupies a portion of the traditional cavity on the side of the outlet valve diaphragm 27 facing away from pump chamber b, the amount of material that needs to be etched away from the silicon wafer 2 is reduced, which helps shorten the etching process time and thus lowers process costs.

[0043] In a preferred embodiment, the silicon wafer 2 has a first through hole 29 located outside the first groove 20. A second groove for connecting the first through hole 29 and the outlet valve is etched on the second surface of the silicon wafer 2. That is, after the second sealing piece 3 covers the second groove, a connecting flow channel c connecting the first through hole 29 and the outlet valve is formed. The first sealing piece 1 has an outlet 11 communicating with the first through hole 29 at the corresponding position, and the second sealing piece 3 has an inlet 32 ​​corresponding to the position of the inlet valve 21. See also... Figure 3 and Figure 4When the micropump is working, the power provided by the driver is transmitted to the moving body 22 through the connection port 33. The driver pulls the moving body 22, that is, the moving body 22 moves towards the connection port 33 under the action of the driver, which increases the volume of the pump chamber b and decreases the internal pressure of the pump chamber b. The inlet valve 21 opens under the drive of the pressure difference, that is, the valve body of the inlet valve 21 moves towards the pump chamber b, so that the inlet port 32 is connected to the inlet flow channel a, and the fluid flows in from the inlet flow channel a. At this time, the outlet valve remains closed. The driver pushes the pump diaphragm 24, that is, the moving body 22 moves towards the pump chamber b under the action of the driver, which decreases the volume of the pump chamber b and increases the internal pressure of the pump chamber b. The outlet valve opens under the action of the pressure difference, that is, the valve body of the outlet valve moves towards the connection flow channel c, so that the pump chamber b is connected to the central flow channel 25, and the liquid flows out from the central flow channel 25 of the outlet valve. At this time, the inlet valve 21 is pressed and is in the closed state. After the liquid flows out of the central flow channel 25 of the outlet valve, it passes through the connecting flow channel c and the first through hole 29 in sequence, and finally reaches the outlet 11. The actuator repeatedly pushes and pulls the moving body 22 to realize the pumping of the fluid, that is, the fluid is pumped from the inlet 32 ​​to the outlet 11.

[0044] like Figure 1 As shown, the outlet 11 is located on the first sealing plate 1, and the inlet 32 ​​is located on the second sealing plate 3, forming a structure where the inlet and outlet are on opposite sides. That is, the inlet 32 ​​and the outlet 11 are located on opposite sides of the micropump. This avoids the inlet pipe, driver, and outlet pipe being arranged on the same side of the micropump, thus helping to reduce the size of the micropump. If the inlet pipe, driver, and outlet pipe were arranged on the same side of the micropump, a certain distance must be maintained between them, resulting in a larger micropump size to accommodate all three components on the same side. It is easy to understand that reducing the size of the micropump allows for a greater number of micropumps to be arranged on the raw material wafer used to manufacture it, thus increasing wafer utilization and reducing the cost of mass-producing micropumps.

[0045] like Figure 5 As shown, Embodiment 2 of the present invention provides a micropump, which is... Figure 1 and Figure 2 The difference between the illustrated embodiment one and embodiment two is that the liquid outlet is located on the second sealing plate 3. Specifically, the second sealing plate 3 has a liquid outlet at the position corresponding to the central flow channel 25 of the outlet valve. When pumping liquid, the liquid flow direction is as follows... Figure 5As shown by the dashed arrow, the liquid flows out from the pump chamber b through the outlet channel d. In Embodiment 2, similar to Embodiment 1, the arrangement of the first valve body 26 avoids the formation of a large cavity in the outlet valve, which would lead to the accumulation of a large amount of liquid. This reduces the risk of liquid freezing and expansion, which could damage the outlet structure, when the micropump is used in a low-temperature environment (below 0°C), thus improving the service life of the micropump. Moreover, compared with traditional micropumps, since the first valve body 26 occupies part of the traditional cavity of the outlet valve, the amount of material that needs to be etched away from the silicon wafer 2 is reduced, which can relatively reduce the etching process time and thus reduce the process cost.

[0046] In practical applications, the first sealing sheet 1 and the second sealing sheet 3 can be made of glass sheets. Of course, the sealing sheets can also be made of other materials, such as silicon wafers. Figure 1 As shown, since the inlet valve 21 is a moving part, in order to prevent the inlet valve 21 from being bonded to the second sealing plate 3 when the silicon wafer 2 is bonded to the second sealing plate 3, a first anti-bonding part 31 can be provided on the second sealing plate 3 at the position corresponding to the inlet valve 21. Similarly, a second anti-bonding part 34 can be provided around the connection port 33 on the side of the second sealing plate 3 facing the silicon wafer 2 to prevent the moving body 22 and the annular rib 23 from being bonded to the second sealing plate 3.

[0047] The structure of the ring reinforcement 23 can be selected in various ways. For example, the ring reinforcement 23 can be set as follows: Figure 6 The single-ring structure shown can also be configured as follows: Figure 7 The double-ring structure shown can also be configured as follows: Figure 8 The discontinuous structure is shown. When the annular rib 23 is a double-ring structure, the annular rib 23 includes a first ring and a second ring arranged concentrically around the moving body 22. The gap between the first ring and the second ring satisfies the same width condition as the groove between the annular rib 23 and the moving body 22 to ensure the uniformity of etching. Similarly, when the annular rib 23 is a discontinuous structure, the annular rib 23 may include multiple discontinuous bodies spaced around the moving body 22. The gap between the discontinuous bodies satisfies the same width condition as the groove between the annular rib 23 and the moving body 22. In addition, when the annular rib 23 is a discontinuous structure, the annular rib 23 may also be set as a lattice structure, including multiple lattice-distributed circular pillars ( Figure 9 The illustrated embodiment) or square column ( Figure 10 (Example shown).

[0048] Similar to the structure of the annular rib 23, the structure of the first valve body 26 can be selected in various ways. For example, the first valve body 26 can be set as follows: Figure 11 The single-ring structure shown can also be configured as follows: Figure 12 The double-ring structure shown can also be configured as follows: Figure 13The discontinuous structure is shown. When the first valve body 26 has a double-ring structure, the first valve body 26 includes a third ring and a fourth ring concentrically arranged around the central flow channel 25 of the outlet valve. The gap between the third ring and the fourth ring and the groove between the annular rib 23 and the moving body 22 satisfy the same width condition to ensure the uniformity of etching. Figure 13 In the illustrated embodiment, the first valve body 26 includes an annular body and a plurality of discontinuous bodies spaced apart around the central flow channel 25 of the outlet valve. The gaps between the discontinuous bodies and the grooves between the discontinuous bodies and the annular body satisfy the same width condition. Furthermore, when the first valve body 26 is a discontinuous structure, it can also be configured as a lattice structure, including a plurality of lattice-distributed circular pillars (…). Figure 14 The illustrated embodiment) or square column ( Figure 15 (Example shown).

[0049] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0050] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A micropump, characterized in that, include: A silicon wafer has a first side and a second side facing each other. The first side is etched with a first groove for forming a pump chamber. The second side is etched with a plurality of grooves that meet the condition of equal width for forming a moving body, an annular rib and a first valve body for forming an outlet valve. The annular rib surrounds the moving body and is connected to a pump diaphragm around the moving body. The first valve body is connected to the valve diaphragm of the outlet valve. A first sealing sheet is fixed to the first side of the silicon wafer to seal the first groove and form a pump chamber. The second sealing plate is fixed to the second side of the silicon wafer, and the second sealing plate has a connection port for connecting the driver at the position corresponding to the moving body.

2. The micropump according to claim 1, characterized in that, The silicon wafer has a first through hole at a position other than the first groove, and the second surface is etched with a second groove for connecting the first through hole and the outlet valve. The first sealing plate has an outlet port that communicates with the first through hole at the position corresponding to the first through hole, and the second sealing plate has an inlet port at the position corresponding to the inlet valve.

3. The micropump according to claim 1, characterized in that, The annular rib includes a plurality of discontinuous bodies distributed at intervals around the moving body, and the gaps between the discontinuous bodies and the groove between the annular rib and the moving body satisfy the condition of equal width.

4. The micropump according to claim 1, characterized in that, The annular rib has a double-ring structure, including a first ring and a second ring arranged concentrically around the moving body. The gap between the first ring and the second ring and the groove between the annular rib and the moving body satisfy the condition of equal width.

5. The micropump according to claim 1, characterized in that, The first valve body has a double-ring structure, including a third ring and a fourth ring arranged concentrically around the central flow channel of the outlet valve. The gap between the third ring and the fourth ring and the groove between the annular rib and the moving body satisfy the condition of equal width.

6. The micropump according to claim 1, characterized in that, The annular ribs have a lattice structure, comprising multiple circular or square columns with lattice distribution.

7. The micropump according to claim 1, characterized in that, The first valve body has a dot matrix structure, comprising multiple circular or square columns distributed in a dot matrix.

8. The micropump according to any one of claims 1 to 7, characterized in that, The first sealing sheet and / or the second sealing sheet are configured as glass sheets or silicon wafers.

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