Piezoelectric sensing structure and flowmeter

Abstract

The invention relates to the technical field of measuring devices, and particularly discloses a piezoelectric sensing structure and a flowmeter, the piezoelectric sensing structure comprises a chip substrate, a diaphragm layer and a piezoelectric layer; a deformation through groove is formed in the chip substrate; the vibrating diaphragm layer is arranged on the chip substrate; the piezoelectric layer is arranged on the vibrating diaphragm layer, the piezoelectric layer comprises a bonding pad part and a deformation part connected to the bonding pad part, the bonding pad part and the chip substrate are oppositely arranged, and the deformation part and the deformation through groove are oppositely arranged; a fluid to be measured can flow through the surface of the piezoelectric layer. When the piezoelectric sensing structure is used for measuring the flow velocity of the to-be-measured fluid, the to-be-measured fluid does not need to be heated, so that the piezoelectric sensing structure can be suitable for a heat-sensitive material, and because the piezoelectric sensing structure is not sensitive to the temperature influence, special heat preservation treatment is not needed on packaging, so that the piezoelectric sensing structure can be miniaturized, and the cost is reduced. And the device can be conveniently integrated into micro flow systems such as a micro-fluidic system and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring devices, and in particular to a piezoelectric sensing structure and a flow meter. Background Art

[0002] A flow meter is an instrument used to measure the flow of a fluid. It can indicate the instantaneous flow rate of the measured fluid and the total amount within a selected time interval. It is widely used in industrial production, scientific research, environmental protection and other fields. At present, thermal flow meters are mainly used in scenarios that require small flow meters with high integration.

[0003] In the prior art, thermal flow meters need to heat the fluid when measuring the fluid, which makes them unsuitable for heat-sensitive materials. In addition, since thermal flow meters are sensitive to temperature, special insulation treatment is required in the packaging, which ultimately results in a large packaging volume for the thermal flow meter and is not easy to integrate into micro flow systems such as microfluidics. Summary of the invention

[0004] The purpose of the present invention is to provide a piezoelectric sensing structure and a flow meter to solve the problems in the prior art that the thermal flow meter is not suitable for heat-sensitive materials and its final packaging volume is large and difficult to be integrated into micro flow systems such as microfluidics.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In one aspect, the present invention provides a piezoelectric sensing structure for measuring the flow velocity of a fluid to be measured, the piezoelectric sensing structure comprising:

[0007] A chip substrate, wherein the chip substrate is provided with a deformation-changing groove;

[0008] A diaphragm layer, wherein the diaphragm layer is disposed on the chip substrate;

[0009] A piezoelectric layer, wherein the piezoelectric layer is disposed on the diaphragm layer; the piezoelectric layer comprises a pad portion and a deformation portion connected to the pad portion, the pad portion is disposed opposite to the chip substrate, and the deformation portion is disposed opposite to the deformation groove; the fluid to be measured can flow through the surface of the piezoelectric layer.

[0010] As an optional solution of the above-mentioned piezoelectric sensing structure, the length direction of the deformation portion is perpendicular to the flow direction of the fluid to be measured; or the length direction of the deformation portion is parallel to the flow direction of the fluid to be measured.

[0011] As an optional solution of the above-mentioned piezoelectric sensing structure, the area of ​​the deformation portion is smaller than the area of ​​the deformation groove; or the area of ​​the deformation portion is greater than or equal to the area of ​​the deformation groove.

[0012] As an optional solution to the above-mentioned piezoelectric sensing structure, the piezoelectric layer is integrally formed; or the piezoelectric layer is divided into a first piezoelectric layer and a second piezoelectric layer, and the deformation portion of the first piezoelectric layer and the deformation portion of the second piezoelectric layer are spaced apart.

[0013] As an optional solution of the above-mentioned piezoelectric sensing structure, a plurality of the deformation parts are provided, and the plurality of the deformation parts are sequentially spaced and connected in parallel to the pad part.

[0014] As an optional solution of the above-mentioned piezoelectric sensing structure, the chip substrate is a silicon wafer substrate, a glass wafer substrate or an SOI wafer substrate.

[0015] As an optional solution of the above-mentioned piezoelectric sensing structure, the piezoelectric layer is a lead zirconate titanate layer or an aluminum nitride layer.

[0016] As an optional solution of the above-mentioned piezoelectric sensing structure, the piezoelectric sensing structure further includes a spoiler layer, and the spoiler layer is arranged on the deformation part.

[0017] As an optional solution of the above-mentioned piezoelectric sensing structure, the spoiler layer is a photoresist layer or a glass layer.

[0018] In another aspect, the present invention provides a flow meter, comprising the piezoelectric sensing structure as described above.

[0019] The beneficial effects of the present invention are:

[0020] The piezoelectric sensing structure includes a chip substrate, a diaphragm layer and a piezoelectric layer. The chip substrate is provided with a deformation groove, and the diaphragm layer is arranged on the chip substrate, so that the diaphragm layer at the deformation groove can be deformed. At the same time, the piezoelectric layer is arranged on the diaphragm layer, and the piezoelectric layer includes a pad portion and a deformation portion connected to the pad portion. The pad portion is arranged relative to the chip substrate, and the deformation portion is arranged relative to the deformation groove, so that the pad portion can stably connect the circuit, the deformation portion can deform following the diaphragm layer, and the fluid to be measured can flow through the surface of the piezoelectric layer, so that the deformation portion can be directly impacted by the fluid to be measured, so that the deformation portion is deformed and generates different electrical signals to correspond to the flow rate of the fluid to be measured. When the piezoelectric sensing structure measures the flow rate of the fluid to be measured, there is no need to heat the fluid to be measured, so it can be applied to heat-sensitive materials. Moreover, since the piezoelectric sensing structure is not sensitive to temperature, no special insulation treatment is required in the packaging, so that the piezoelectric sensing structure can be miniaturized and easily integrated into micro flow systems such as microfluidics. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A first structural schematic diagram of a first piezoelectric sensing structure provided by an embodiment of the present invention;

[0022] Figure 2A second structural schematic diagram of the first piezoelectric sensing structure provided by an embodiment of the present invention;

[0023] Figure 3 A first structural schematic diagram of a second piezoelectric sensing structure provided by an embodiment of the present invention;

[0024] Figure 4 A second structural schematic diagram of a second piezoelectric sensing structure provided by an embodiment of the present invention;

[0025] Figure 5 A first structural schematic diagram of a third piezoelectric sensing structure provided by an embodiment of the present invention;

[0026] Figure 6 A second structural schematic diagram of a third piezoelectric sensing structure provided by an embodiment of the present invention;

[0027] Figure 7 A first structural schematic diagram of a fourth piezoelectric sensing structure provided by an embodiment of the present invention;

[0028] Figure 8 A second structural schematic diagram of a fourth piezoelectric sensing structure provided by an embodiment of the present invention;

[0029] Fig. 9 A first structural schematic diagram of a fifth piezoelectric sensing structure provided by an embodiment of the present invention;

[0030] Fig.10 A second structural schematic diagram of the fifth piezoelectric sensing structure provided by an embodiment of the present invention;

[0031] Fig.11 A first structural schematic diagram of a sixth piezoelectric sensing structure provided by an embodiment of the present invention;

[0032] Fig.12 A second structural schematic diagram of a sixth piezoelectric sensing structure provided by an embodiment of the present invention;

[0033] Fig.13 A first structural schematic diagram of a seventh piezoelectric sensing structure provided by an embodiment of the present invention;

[0034] Fig.14 A second structural schematic diagram of the seventh piezoelectric sensing structure provided by an embodiment of the present invention;

[0035] Fig.15 A first structural schematic diagram of an eighth piezoelectric sensing structure provided by an embodiment of the present invention;

[0036] Fig.16 A second structural schematic diagram of an eighth piezoelectric sensing structure provided by an embodiment of the present invention;

[0037] Fig.17 A first structural schematic diagram of a ninth piezoelectric sensing structure provided by an embodiment of the present invention;

[0038] Fig.18 This is a second structural schematic diagram of the ninth piezoelectric sensing structure provided in an embodiment of the present invention.

[0039] In the figure:

[0040] 1. Chip substrate; 11. Deformation groove; 2. Diaphragm layer; 3. Piezoelectric layer; 31. Pad portion; 32. Deformation portion; 4. Spoiler layer. DETAILED DESCRIPTION

[0041] 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 the embodiments. 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.

[0042] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature "above", "above" and "above" the second feature include the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature include the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0043] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0045] like Figures 1 to 18 As shown, this embodiment provides a piezoelectric sensing structure for measuring the flow velocity of a fluid to be measured.

[0046] The piezoelectric sensing structure includes a chip substrate 1, a diaphragm layer 2 and a piezoelectric layer 3. The chip substrate 1 is provided with a deformation groove 11, and the diaphragm layer 2 is arranged on the chip substrate 1, so that the diaphragm layer 2 at the deformation groove 11 can be deformed. At the same time, the piezoelectric layer 3 is arranged on the diaphragm layer 2, and the piezoelectric layer 3 includes a pad portion 31 and a deformation portion 32 connected to the pad portion 31. The pad portion 31 is arranged relative to the chip substrate 1, and the deformation portion 32 is arranged relative to the deformation groove 11, so that the pad portion 31 can stably connect the circuit, and the deformation portion 32 can deform with the diaphragm layer 2, and the fluid to be measured can flow through the surface of the piezoelectric layer 3, so that the deformation portion 32 can be directly impacted by the fluid to be measured, so that the deformation portion 32 is deformed and generates different electrical signals to correspond to the flow rate of the fluid to be measured. Optionally, the chip substrate 1 and the diaphragm layer 2 are integrally formed.

[0047] When the piezoelectric sensing structure measures the flow rate of the fluid to be measured, there is no need to heat the fluid to be measured, so that it can be applied to heat-sensitive materials, and because the piezoelectric sensing structure is not sensitive to temperature, no special insulation treatment is required in the package, so that the piezoelectric sensing structure can be miniaturized and easily integrated into micro flow systems such as microfluidics. Optionally, the chip substrate 1 is a silicon wafer substrate or a glass wafer substrate or an SOI wafer substrate, so that the chip substrate 1 has good chemical stability and physical stability, and is not easy to react with other elements or compounds, thereby meeting the requirements as a substrate. Further optionally, the piezoelectric layer 3 is a lead zirconate titanate layer or an aluminum nitride layer, so that the piezoelectric layer 3 has good piezoelectric and dielectric properties, high hardness and elastic modulus, so as to facilitate deformation and generate different electrical signals to correspond to the flow rate of the fluid to be measured.

[0048] In one embodiment, if Figure 1 and Figure 2 As shown, the length direction of the deformation portion 32 is perpendicular to the flow direction of the fluid to be measured, so that the piezoelectric sensing structure can measure a longer section of the fluid to be measured in the horizontal length, thereby meeting the actual measurement requirements, wherein the piezoelectric layer 3 can be a rectangular structure. In another embodiment, as Figure 3 and Figure 4As shown, the length direction of the deformation portion 32 is parallel to the flow direction of the fluid to be measured, so that the piezoelectric sensing structure can measure a longer section of the fluid to be measured in the longitudinal length, thereby meeting actual measurement requirements, wherein the piezoelectric layer 3 can be a Z-shaped structure.

[0049] In one embodiment, if Figure 1 to Figure 4 , Figure 7 and Figure 8 As shown, the area of ​​the deformation portion 32 is smaller than the area of ​​the deformation slot 11, so that the deformation slot 11 can completely cover the deformation portion 32, thereby meeting the actual measurement requirements. Figure 5 , Figure 6 , Fig. 9 and Fig.10 As shown, the area of ​​the deformation portion 32 is greater than or equal to the area of ​​the deformation slot 11, so that the deformation portion 32 can completely cover the deformation slot 11, thereby meeting actual measurement requirements.

[0050] In one embodiment, if Figure 1 to Figure 6 , Fig.11 , Fig.12 , Fig.15 and Fig.16 As shown, the piezoelectric layer 3 is integrally formed, thereby facilitating the production of the piezoelectric sensing structure and meeting actual measurement requirements. Figure 7 to Figure 10 , Fig.13 , Fig.14 , Fig.17 and Fig.18 As shown, the piezoelectric layer 3 is divided into a first piezoelectric layer and a second piezoelectric layer. The deformation portion 32 of the first piezoelectric layer is spaced apart from the deformation portion 32 of the second piezoelectric layer, so that the first piezoelectric layer and the second piezoelectric layer can measure the flow velocity of the fluid to be measured from both sides, thereby improving the measurement accuracy and meeting the actual measurement requirements.

[0051] Specifically, Figures 11 to 18 As shown, a plurality of deformation parts 32 are provided, and the plurality of deformation parts 32 are sequentially spaced and connected in parallel to the pad part 31, so that when the piezoelectric layer 3 is integrally formed, the plurality of deformation parts 32 can respectively measure the flow velocity of the fluid to be measured, and then perform an average calculation, so as to improve the measurement accuracy and meet the actual measurement needs, wherein the piezoelectric layer 3 can be a fence structure; when the piezoelectric layer 3 is divided into a first piezoelectric layer and a second piezoelectric layer, the first piezoelectric layer and the second piezoelectric layer can respectively measure the flow velocity of the fluid to be measured from both sides, and a plurality of deformation parts 32 are provided on each side, so as to improve the measurement accuracy and meet the actual measurement needs, wherein the first piezoelectric layer and the second piezoelectric layer are both comb-like structures.

[0052] Furthermore, if Figure 15 to Figure 18As shown, the piezoelectric sensing structure further includes a spoiler layer 4, which is disposed on the deformation portion 32. The spoiler layer 4 can stop the fluid to be measured, so as to amplify the deformation of laminar flow or other conditions that are not likely to cause deformation of the diaphragm layer 2, thereby improving the measurement accuracy. Optionally, the spoiler layer 4 is a photoresist layer or a glass layer, so that it is less difficult to arrange the spoiler layer 4 on the deformation portion 32, thereby reducing the manufacturing difficulty.

[0053] The present embodiment also provides a flow meter, including the piezoelectric sensing structure as described above. By using the piezoelectric sensing structure as described above, the flow meter does not need to heat the fluid to be measured, so it can be suitable for heat-sensitive materials. Since the piezoelectric sensing structure is not sensitive to temperature, no special insulation treatment is required in the packaging, so that the piezoelectric sensing structure can be miniaturized and easily integrated into micro flow systems such as microfluidics.

[0054] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A piezoelectric sensing structure for measuring the flow velocity of a fluid to be measured, characterized in that: The piezoelectric sensing structure comprises: A chip substrate (1), wherein the chip substrate (1) is provided with a deformation-changing groove (11); A diaphragm layer (2), the diaphragm layer (2) being arranged on the chip substrate (1); A piezoelectric layer (3), the piezoelectric layer (3) being arranged on the diaphragm layer (2); the piezoelectric layer (3) comprising a pad portion (31) and a deformation portion (32) connected to the pad portion (31), the pad portion (31) being arranged opposite to the chip substrate (1), and the deformation portion (32) being arranged opposite to the deformation groove (11); the fluid to be measured can flow through the surface of the piezoelectric layer (3).

2. The piezoelectric sensing structure according to claim 1, characterized in that: The length direction of the deformation portion (32) is perpendicular to the flow direction of the fluid to be measured; or the length direction of the deformation portion (32) is parallel to the flow direction of the fluid to be measured.

3. The piezoelectric sensing structure according to claim 1, characterized in that: The area of ​​the deformation portion (32) is smaller than the area of ​​the deformation groove (11); or the area of ​​the deformation portion (32) is greater than or equal to the area of ​​the deformation groove (11).

4. The piezoelectric sensing structure according to claim 1, characterized in that: The piezoelectric layer (3) is integrally formed; or the piezoelectric layer (3) is divided into a first piezoelectric layer and a second piezoelectric layer, and the deformation portion (32) of the first piezoelectric layer is spaced apart from the deformation portion (32) of the second piezoelectric layer.

5. The piezoelectric sensing structure according to claim 4, characterized in that: A plurality of the deformation parts (32) are provided, and the plurality of the deformation parts (32) are sequentially spaced and connected in parallel to the pad part (31).

6. The piezoelectric sensing structure according to any one of claims 1 to 5, characterized in that: The chip substrate (1) is a silicon wafer substrate, a glass wafer substrate or an SOI wafer substrate.

7. The piezoelectric sensing structure according to any one of claims 1 to 5, characterized in that: The piezoelectric layer (3) is a lead zirconate titanate layer or an aluminum nitride layer.

8. The piezoelectric sensing structure according to any one of claims 1 to 5, characterized in that: The piezoelectric sensing structure further comprises a spoiler layer (4), wherein the spoiler layer (4) is arranged on the deformation portion (32).

9. The piezoelectric sensing structure according to claim 8, characterized in that: The spoiler layer (4) is a photoresist layer or a glass layer.

10. A flow meter, characterized in that: It comprises the piezoelectric sensing structure as described in any one of claims 1 to 9.

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