MEMS micro valve and micro pump

Abstract

The MEMS micro valve is arranged in a fluid channel and used for controlling closing and opening of the fluid channel, the technical problem that a valve body cannot be opened is solved, the MEMS micro valve comprises the valve body, a valve seat and a cantilever beam, the fluid channel is closed when the valve body covers the valve seat, and the fluid channel is opened when the valve body is separated from the valve seat. The cantilever beam is connected between the valve body and the inner wall of the fluid channel to play a role in supporting the valve body, and a separation space is arranged between the cantilever beam and / or the valve body and an object to reduce the contact area with the object. The invention further provides an MEMS micropump, the MEMS micropump comprises a pump cavity capable of changing the size, the pump cavity is provided with a liquid inlet fluid channel and a liquid outlet fluid channel, and the MEMS microvalve is adopted as a one-way valve of the liquid inlet fluid channel and the liquid outlet fluid channel. Separation spaces are arranged between the cantilever beam and an object (a related structure on the micropump) and between the valve body and the object (a valve seat) to reduce the contact area between the cantilever beam and the object and reduce the action of micro force, so that the microvalve is easier to open.

Description

Technical Field

[0001] The invention belongs to the field of micro-electromechanical systems (MEMS), relates to a MEMS microvalve, and also relates to a MEMS micropump. Background Art

[0002] MEMS micropump is an actuator designed and manufactured using micro-electromechanical system (MEMS) technology, which can realize fluid delivery and control in a microscopic scale. Its pumping accuracy, rate and other indicators are very suitable for the injection of slow-release or trace liquid medicines such as insulin, anesthetics and analgesics.

[0003] The main principle of MEMS micropump is to use the movement of pump membrane to cause the volume change of pump chamber, so that there is a pressure difference between the chamber and the outside world, and the valve is opened and closed by the pressure difference to realize the pumping of fluid. Therefore, the normal opening and closing of the valve in the micropump is one of the key indicators to ensure the operation of the micropump.

[0004] Chinese patent documents "CN118728715A" and "CN118775225A" record corresponding MEMS micro pumps, but the inlet valves recorded in the above two patent documents may not open normally. The present invention is an improvement on this basis. Summary of the invention

[0005] The purpose of the present invention is to provide a MEMS microvalve and a micropump to solve the technical problem that the microvalve cannot be opened.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: The present invention provides a MEMS microvalve, which is arranged in a fluid channel and is used to control the closing and opening of the fluid channel. The valve body comprises a valve seat and a cantilever beam. When the valve body covers the valve seat, the fluid channel is closed, and when the valve body is separated from the valve seat, the fluid channel is opened. The cantilever beam is connected between the valve body and the inner wall of the fluid channel to support the valve body. A separation space is provided between the cantilever beam and / or the valve body and an object to reduce the contact area with the object.

[0007] Preferably, the separation space corresponding to the cantilever beam is formed by the fluid channel extending into the side of the cantilever beam facing the object.

[0008] Furthermore, the valve body extends along with the fluid channel toward the side of the cantilever beam facing the object.

[0009] Preferably, the separation space corresponding to the cantilever beam is formed by a hole etched in an object of the cantilever beam.

[0010] Preferably, the separation space corresponding to the cantilever beam is formed by a hole etched in the cantilever beam.

[0011] Preferably, the separation space corresponding to the valve body is etched on the end surface of the valve body.

[0012] Preferably, the separation space corresponding to the valve body is etched on the valve seat.

[0013] Preferably, the separation space corresponding to the valve body is continuous or intermittent.

[0014] Preferably, the contact area between the valve body and the valve seat is annular, the separation space is arranged on the valve body and / or the valve seat, and the separation space is in the shape of one or more rings.

[0015] A MEMS micropump is also provided, comprising a pump chamber capable of changing volume, the pump chamber having an inlet fluid channel and an outlet fluid channel, and any of the aforementioned MEMS microvalve is used as a one-way valve of the inlet fluid channel and / or the outlet fluid channel.

[0016] Preferably, a pump chamber extension area is etched on the periphery of the end portion of the cantilever beam at the edge of the pump chamber, facing away from the cantilever beam object.

[0017] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: The inventors of the MEMS microvalve and micropump of the present invention have found through research that at the micro-nano scale, the surface area to volume ratio of the microstructure increases, and it is very susceptible to surface effects, and adsorption is one of the most common surface effects. MEMS micropumps are typical micro-nano devices, in which the microvalve structure has a large surface area to volume ratio and a very smooth surface. When a small gap appears in the microvalve structure, the surface effect of adsorption is very likely to occur, making it impossible for the valve body to open effectively. The adsorption surface effect is usually caused by microscopic forces such as capillary force, electrostatic force, and van der Waals force. In the present invention, a separation space is set between the cantilever beam and the object (related structure on the micropump), and between the valve body and the object (valve seat) to reduce the contact area with the object and reduce the effect of microscopic forces, thereby making the microvalve easier to open. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings: Figure 1 This is an exploded view of a MEMS micro pump with a portion cut away, see Chinese patent "CN118775225A"; Figure 2 yes Figure 1AA section view; Figure 3 yes Figure 1 A structural cross-section diagram of Figure 4 yes Figure 3 BB cross-sectional view; Figure 5 yes Figure 3 Enlarged view of point C; Figure 6 is a structural diagram of Embodiment 1 of the present invention, corresponding to Figure 5 ; Figure 7 It is a top view of the inlet valve body; Figure 8 yes Figure 6 Enlarged view of point G in the middle; Fig. 9 This is a bottom view of the inlet valve body; Fig.10 is a bottom view of the inlet valve body of Example 2, and Fig. 9 contrast; Fig.11 is a structural diagram of Example 3, and Figure 6 contrast; Fig.12 is a top view of the inlet valve body of Example 3; Fig.13 is a bottom view of the inlet valve body of Example 4, and Fig. 9 contrast; Fig.14 is a structural diagram of Example 5, and Figure 8 contrast; Fig.15 It is a schematic diagram of a cantilever beam extension formed with the use of the valve in the scheme of embodiment 1; Fig.16 is a structural diagram of Example 5, and Figure 6 contrast; Fig.17 is a top view of the inlet valve body of Example 5, and Figure 7 contrast; The reference numerals are described as follows: 1. Silicon layer; 2. First sealing layer; 3. Second sealing layer; 4. Pump chamber; 41. Pump chamber extension area; 5. Inlet fluid channel; 6. Outlet fluid channel; 7. Inlet valve body; 71. Protrusion; 8. Inlet valve seat; 9. Cantilever beam; 91. Cantilever beam extension; 10. Outlet valve body; 11. Separation space; 111. Circular etching groove; 112. Block etching groove. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] like Figures 1 to 4 The MEMS micro pump shown includes a silicon layer 1, a first sealing layer 2, and a second sealing layer 3. The first sealing layer 2 and the second sealing layer 3 can be made of glass. The first sealing layer 2 and the second sealing layer 3 are encapsulated on the upper and lower surfaces of the silicon layer 1.

[0021] A pump chamber 4 is etched on the silicon layer 1. An inlet fluid channel 5 and an outlet fluid channel 6 are formed by etching at the inlet and outlet of the pump chamber 4, respectively. An inlet valve body 7 and an outlet valve body 10 are respectively arranged in the inlet fluid channel 5 and the outlet fluid channel 6, both of which are one-way valves, and fluid is pumped by the volume change of the pump chamber 4.

[0022] The inlet valve body 7 is connected to the corresponding part of the silicon layer 1 through the cantilever beam 9 (the so-called connection is formed by not etching). The cantilever beam 9 provides support for the inlet valve body 7, supporting the inlet valve body 7 to be located in the inlet fluid channel 5. The inlet fluid channel 5 passes through the second sealing layer 3, then extends to the periphery of the inlet valve body 7, and finally communicates with the pump chamber 4. The part of the second sealing layer 3 facing the inlet valve body 7 forms an inlet valve seat 8, and in this example, the inlet valve seat 8 protrudes from the upper surface of the second sealing layer 3.

[0023] It can be said that the inlet valve body 7 and the inlet valve seat 8 are both arranged in the inlet fluid channel 5. The inlet valve seat 8 is annular. When pumping, the fluid passes through the gap between the inlet valve body 7 and the inlet valve seat 8, reaches the periphery of the inlet valve body 7, and then flows into the pump chamber 4. When the inlet valve body 7 is covered on the inlet valve seat 8 (when the volume of the pump chamber 4 is reduced, the pressure in the pump chamber 4 increases, driving the inlet valve body 7 to move), the gap between the inlet valve body 7 and the inlet valve seat 8 is eliminated, and the inlet fluid channel 5 is closed; when the inlet valve body 7 leaves the inlet valve seat 8 (when the volume of the pump chamber 4 is increased, the pressure in the pump chamber 4 decreases, driving the inlet valve body 7 to move), the gap between the inlet valve body 7 and the inlet valve seat 8 opens, and the inlet fluid channel 5 opens. Therefore, the cooperation between the inlet valve body 7 and the inlet valve seat 8 controls the closing and opening of the inlet fluid channel 5.

[0024] like Figure 5, the gaps at D and E are prone to adsorption, which affects the function of the inlet valve body 7 and makes it impossible for the inlet valve body 7 to open. The cantilever beam 9 and its object (the part indicated by F) are prone to adsorption due to the gap, making it difficult for the cantilever beam 9 to swing upward, which can be called the inlet valve cantilever beam adsorption phenomenon. The inlet valve body 7 and its object (inlet valve seat 8) are prone to adsorption due to the gap, making it difficult for the inlet valve body 7 to separate from the inlet valve seat 8, which can be called the valve body adsorption phenomenon. These phenomena are manifested in the delayed opening or inability to open the inlet fluid channel 5. The aforementioned adsorption surface effect is usually caused by microscopic forces such as capillary force, electrostatic force, and van der Waals force.

[0025] Example 1 To solve this problem, two measures are adopted in this example.

[0026] Measure 1, such as Figure 6 and Figure 7 , increase the etching of the inlet fluid channel 5, extend the portion of the inlet fluid channel 5 located below the cantilever beam 9 in the direction away from the inlet valve body 7, occupy the space of the object below the cantilever beam 9, and the extended portion forms a separation space 11, which reduces the gap length between the cantilever beam 9 and its object, thereby reducing the microscopic force of adsorption between the cantilever beam 9 and the object.

[0027] Measure 2: Figure 8 As shown, in the portion where the inlet valve body 7 contacts the inlet valve seat 8, a microgroove is etched on the end surface of the inlet valve body 7 facing the inlet valve seat 8. The microgroove is a separation space 11, which reduces the contact area between the inlet valve body 7 and the inlet valve seat 8, thereby reducing the size of the adsorption microscopic force between the inlet valve body 7 and the inlet valve seat 8, making the inlet valve body 7 and the inlet valve seat 8 easier to separate.

[0028] The micro grooves etched on the end face of the inlet valve body 7 are shaped as follows: Fig. 9 As shown, there are two circles of discontinuously distributed circular etched grooves 111, and the inner and outer circles are staggered to improve the sealing and uniformity. In this example, the etched microgrooves are discontinuous, and in other embodiments, they can also be continuous, such as one or two circles of annular microgrooves.

[0029] The above measures 1 and 2 can be implemented simultaneously, or one of them can be implemented. Although this example is used for the inlet valve body 7, it can also be used for the outlet valve body in other structure MEMS micro pumps.

[0030] Example 2 like Fig.10 As shown, corresponding to the above measure 1, it can be compared Fig. 9 Structure, the inlet valve body 7 extends along with the inlet fluid channel 5 to the bottom of the cantilever beam 9 ( Fig.10 yes Figure 6The protrusion 71 is formed in the upward viewing direction, and the protrusion 71 reduces the local enlargement of the cavity caused by the extension of the liquid inlet fluid channel 5 to the bottom of the cantilever beam 9, which is beneficial to the flow of liquid and avoids eddy currents caused by the local enlargement of the cavity of the liquid inlet fluid channel 5 after the etched area of ​​the liquid inlet fluid channel 5 is extended.

[0031] Example 3 like Fig.11 and Fig.12 As shown, in this example, a hole is etched in the object below the cantilever beam 9, and the hole forms a separation space 11. The hole can be etched upward from the lower surface of the silicon layer 1. The hole also reduces the area of ​​the gap between the cantilever beam 9 and the object, thereby reducing the size of the adsorption microscopic force between the cantilever beam 9 and the object.

[0032] Example 4 like Fig.13 As shown, Fig. 9 The difference from the illustrated embodiment 1 is that the microgrooves etched on the end surface of the inlet valve body 7 are block-shaped etched grooves 112 that are distributed intermittently, and the inner and outer circles are staggered to improve the sealing performance and uniformity.

[0033] Example 5 like Fig.14 As shown, Figure 8 The difference between the embodiment 1 shown is that the separation space 11 is a micro groove etched on the inlet valve seat 8, rather than being etched on the end surface of the inlet valve body 7. Similarly, the shape of the micro groove can also be as follows: Fig. 9 and Fig.13 The shapes shown are circular or block-shaped. Based on similar ideas, microgrooves can also be etched on the lower surface of the cantilever beam 9.

[0034] Example 6 like Fig.15 The structure shown is Figure 7 The structure of the embodiment 1 after being put into use is shown in FIG. 1. Due to the setting of the separation space 11, the swing speed of the cantilever beam 9 is accelerated when the valve is opened, and the gap under the cantilever beam 9 extends to Fig.15 The cantilever beam 9 is arranged below the cantilever beam extension 91, so that the actual working length of the cantilever beam 9 is extended to include the cantilever beam extension 91, that is, the effective length of the cantilever beam 9 is lengthened. Fig.15 The leftmost side of the cantilever beam 9 is limited by the edge silicon layer material, the effective movement length remains unchanged, and the left end boundary of the cantilever beam 9 is limited to the H line. Therefore, during the valve opening process, the cantilever beam 9 has an unbalanced movement problem. This example can solve this problem.

[0035] like Fig.16 and Fig.17 As shown, the edge of the pump cavity 4 in the silicon layer 1 is etched to remove Fig.16The J portion above the periphery of the end of the middle cantilever beam 9 forms a pump chamber extension area 41, and the etching gap below the cantilever beam 9 here is enlarged to form an extended release space (it can also be formed by natural extension during operation without enlarging the etching gap, such as the other two cantilever beams 9). In this way, the actual working length of the cantilever beam 9 at this location is extended to be equivalent to the other two cantilever beams 9, such as Fig.17 .

[0036] In the aforementioned embodiments, in order to solve the adsorption problem of the inlet valve cantilever beam 9, the original etched area of ​​the inlet fluid channel 5 is extended along the cantilever beam 9, the length of the suspended part of the inlet valve cantilever beam 9 is increased, and then the contact area between the inlet valve cantilever beam 9 and the structure below the cantilever beam 9 is reduced, the microscopic force is reduced, and the adsorption problem of the cantilever beam 9 is solved; in order to solve the adsorption problem of the inlet valve body 7, a shallower etching is added to the inlet valve body 7 at the position where the inlet valve body 7 contacts the bottom glass to form a micro groove, reduce the contact area between the inlet valve body 7 and the inlet valve seat 8, reduce the microscopic force, and solve the adsorption problem of the inlet valve body 7. Finally, the inlet valve body 7 is easy to open, and the performance of the MEMS micro pump is more stable.

[0037] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A MEMS microvalve, arranged in a fluid channel, for controlling the closing and opening of the fluid channel, comprising a valve body, a valve seat and a cantilever beam, wherein the fluid channel is closed when the valve body covers the valve seat, and the fluid channel is opened when the valve body is separated from the valve seat, and the cantilever beam is connected between the valve body and the inner wall of the fluid channel to play a supporting role for the valve body, characterized in that: A separation space is provided between the cantilever beam and / or the valve body and the object to reduce a contact area with the object.

2. The MEMS microvalve according to claim 1, characterized in that: The separation space corresponding to the cantilever beam is formed by the fluid channel extending into the side of the cantilever beam facing the object.

3. The MEMS microvalve according to claim 2, characterized in that: The valve body extends along with the fluid passage toward a side of the cantilever beam facing the object.

4. The MEMS microvalve according to claim 1, characterized in that: The separation space corresponding to the cantilever beam is formed by a hole etched in the object of the cantilever beam or in the cantilever beam.

5. The MEMS microvalve according to claim 1, characterized in that: The separation space corresponding to the valve body is etched on the end surface of the valve body.

6. The MEMS microvalve according to claim 1, characterized in that: The separation space corresponding to the valve body is etched on the valve seat.

7. The MEMS microvalve according to claim 1, characterized in that: The separation space corresponding to the valve body is continuous or intermittent.

8. The MEMS microvalve according to claim 1, characterized in that: The contact area between the valve body and the valve seat is annular, the separation space is arranged on the valve body and / or the valve seat, and the separation space is in the shape of one or more rings.

9. A MEMS micropump, comprising a pump chamber capable of changing volume, the pump chamber having an inlet fluid channel and an outlet fluid channel, characterized in that: The MEMS microvalve described in any one of claims 1 to 9 is used as a one-way valve of the liquid inlet fluid channel and / or the liquid outlet fluid channel.

10. The MEMS micropump according to claim 9, characterized in that: A pump cavity extension area is etched out of the outer periphery of the cantilever beam end portion at the edge of the pump cavity, facing away from the cantilever beam object.

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