High-humidity-resistant MEMS-based olfactory sensor

Abstract

The invention relates to the technical field of gas detection, provides a high-humidity-resistant MEMS-based olfactory sensor, and can solve the technical problems that water vapor easily enters the olfactory sensor, the detection precision is low, and the failure rate is high. The high-humidity-resistant MEMS-based olfactory sensor comprises a shell, a gas detection assembly and a filtering assembly, wherein the shell comprises a gas inlet; the gas detection assembly is arranged in the shell; the filtering assembly is arranged on the side, facing the gas inlet, of the gas detection assembly and comprises a waterproof breathable film and an activated carbon layer; the activated carbon layer is arranged between the gas detection assembly and the waterproof breathable film; wherein the waterproof breathable film is a polymer film with a microporous structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas detection, and particularly relates to a MEMS-based olfactory sensor resistant to high humidity. BACKGROUND

[0002] An olfactory sensor, also known as an electronic nose, is an electronic device that detects, analyzes and identifies complex gas components by simulating the working principle of a biological olfactory system. The sensor array is exposed to the target gas to generate response signals, and the types or concentrations of the gas can be identified by pattern recognition of the signals.

[0003] In the related art, the sensing element is protected by a shell, the shell is provided with a gas permeable hole, and external air is introduced into the shell through the gas permeable hole to realize odor detection. However, the introduced air may contain water vapor, which not only affects the detection accuracy, but also may corrode the sensing element and other electrical components.

[0004] Therefore, the related art has the technical problems that water vapor easily enters the olfactory sensor, the detection accuracy is low, and the failure rate is high. SUMMARY

[0005] To solve the above technical problems, the present application provides a MEMS-based olfactory sensor resistant to high humidity. The MEMS-based olfactory sensor resistant to high humidity can block water vapor without affecting the flow of gas by arranging a waterproof and air-permeable film between the gas inlet and the gas detection assembly.

[0006] In a first aspect, the present application provides a MEMS-based olfactory sensor resistant to high humidity, which comprises: a shell comprising a gas inlet; a gas detection assembly arranged in the shell; a filter assembly arranged on the side of the gas detection assembly facing the gas inlet, the filter assembly comprising a waterproof and air-permeable film and an activated carbon layer; the activated carbon layer is arranged between the gas detection assembly and the waterproof and air-permeable film; wherein the waterproof and air-permeable film is a polymer film with a microporous structure.

[0007] The arrangement of the filter assembly on the side of the gas detection assembly facing the gas inlet indicates the front position relationship of the filter assembly in the gas flow path. The gas to be detected must pass through the filter assembly first before reaching the gas detection assembly behind.

[0008] After the gas to be detected passes through the gas inlet, it first reaches the filter assembly. The waterproof and air-permeable film performs a filtering function by virtue of its microporous characteristics, blocking the water vapor and pollutant particles contained in the gas to be detected, and achieving pretreatment of the gas to be detected. The dry and clean gas to be detected after the pretreatment diffuses to the gas detection assembly, so that the gas detection assembly can stably work in a dry and clean environment, so that the gas detection assembly only responds to target gas molecules, avoiding performance degradation and physical damage caused by water condensation and pollution coverage.

[0009] The application adds a filter assembly with a waterproof and breathable film as the core between the gas detection assembly and the gas inlet, and constructs an effective physical barrier. The physical barrier solves the technical problems of sensor accuracy decline, poor reliability and short service life caused by water vapor and pollutants in the prior art, and achieves the technical effects of improving the environmental adaptability and long-term working stability of the anti-high-humidity MEMS-based olfactory sensor in a complex humid environment.

[0010] In some implementations, the waterproof and breathable film is prepared by an expanded polytetrafluoroethylene material, and the activated carbon layer includes iodide and / or metal oxide.

[0011] In some implementations, the filter assembly includes at least two layers of waterproof and breathable films, and the at least two layers of waterproof and breathable films are distributed in the axial direction of the gas inlet.

[0012] In some implementations, the filter assembly further includes a support member arranged between the gas detection assembly and the gas inlet, and the waterproof and breathable film is arranged on the support member, and the support member is used to support the waterproof and breathable film.

[0013] In some implementations, in the case that the filter assembly includes at least two layers of waterproof and breathable films, the support member and the waterproof and breathable film are one-to-one corresponding, and in the axial direction of the gas inlet, the support member and the waterproof and breathable film are alternately arranged.

[0014] In some implementations, the support member includes a metal mesh and a support ring, the support ring abuts against the gas detection assembly or the adjacent waterproof and breathable film, the metal mesh is arranged on one side of the support ring close to the gas inlet, and the waterproof and breathable film is laid on the metal mesh.

[0015] In some implementations, the filter assembly includes two waterproof and breathable films and an activated carbon layer, and the activated carbon layer is located between the two waterproof and breathable films.

[0016] In some implementations, the gas detection assembly includes a circuit board, a MEMS gas sensor array and a microprocessor, the circuit board is arranged in the housing, the MEMS gas sensor array includes a plurality of MEMS gas sensitive elements, the MEMS gas sensitive elements have cross-sensitivity to the target gas, the MEMS gas sensitive elements are integrated on the circuit board in a surface mount manner, the microprocessor is connected with the circuit board, and is used to collect response signals of the plurality of MEMS gas sensitive elements, and perform data processing and pattern recognition on the response signals, and output gas concentration data and recognition results.

[0017] In some implementations, the MEMS gas sensitive element is a metal oxide semiconductor gas sensor, and the MEMS gas sensitive element is packaged in a grid array form.

[0018] In some implementations, the circuit board comprises a first circuit board and a second circuit board electrically connected, the first circuit board and the second circuit board are distributed along a first direction, the MEMS gas sensor array is arranged on the first circuit board, and the microprocessor is arranged on the second circuit board, and a pin is arranged on a side of the second circuit board facing away from the first circuit board. BRIEF DESCRIPTION OF DRAWINGS

[0019] The drawings incorporated in and forming a part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required to be used in the embodiments or the prior art description will be briefly introduced as follows, and obviously, other drawings can also be obtained by those of ordinary skill in the art without any creative labor under the premise of these drawings.

[0021] Figure 1 Structure diagram of the olfactory sensor of the embodiment of the present application;

[0022] Figure 2 Exploded view of the olfactory sensor of the embodiment of the present application;

[0023] Figure 3 Exploded view of the olfactory sensor of the embodiment of the present application;

[0024] Figure 4 Structure diagram of the gas detection assembly of the olfactory sensor of the embodiment of the present application.

[0025] Explanation of reference signs:

[0026] 100-olfactory sensor; 1-housing; 11-air inlet; 2-gas detection assembly; 21-circuit board; 211-first circuit board; 214-second circuit board; 215-pin; 22-MEMS gas sensor array; 221-MEMS gas sensitive element; 23-microprocessor; 3-filter assembly; 31-waterproof air-permeable membrane; 32-activated carbon layer; 33-support; 331-metal mesh; 332-support ring; X-first direction. DETAILED DESCRIPTION

[0027] In order to enable one skilled in the art to more clearly understand the above-mentioned purposes, features and advantages of the present application, the scheme of the present application will be further described below. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0028] Many particular details are set forth in the following description in order to provide a thorough understanding of the application. However, the application can be practiced according to the claims without some or all of these details. Needless to say, the description is only one possible implementation of the application and is not intended to limit the true scope of the application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. The use herein of terms such as "comprise", "comprises", "comprising", "including", "includes", "contain", "contains" or "containing", or any other variation thereof, is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus that comprises a list of elements is not required to comprise only those elements on the list.

[0030] In the description of the embodiments of the present application, the technical terms "first", "second", "third", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0031] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification is not necessarily all referring to the same embodiment, or to a particular embodiment that is separate or alternative to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0032] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A existing alone, A and B existing together, and B existing alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are "or" relationship.

[0033] In the description of the embodiments of the present application, the technical terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and are not intended to indicate or imply that the indicated device or element must have a particular orientation, be constructed in a particular orientation, be operated or used, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0034] In the description of the embodiments of the present application, unless explicitly defined and limited otherwise, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0035] In the description of the embodiments of the present application, unless explicitly defined and limited otherwise, the technical term "contact" should be understood in a broad sense, which can be direct contact or contact through an intermediate medium layer, which can be contact between two contacting objects without interaction force, or contact between two contacting objects with interaction force.

[0036] Next, the present application is described in detail.

[0037] In the actual application scene of the olfactory sensor, it is inevitably exposed to a complex and variable atmospheric environment, and water vapor is a key factor affecting its long-term reliability and measurement accuracy.

[0038] In the related art, the air holes formed on the shell are not protected against water vapor, and high humidity water vapor in the environment can enter the inside of the device shell through the air holes. These water vapors will condense on the surface of the circuit board and the precise MEMS gas sensitive element, which may not only cause hardware failures such as metal circuit corrosion and micro-short circuit, but also contaminate the surface activity of the MEMS gas sensitive element. Especially for a micro-electro-mechanical system metal oxide semiconductor gas sensor, the water film on the surface of the sensitive material will hinder the effective contact and reaction of target gas molecules with the sensitive material, resulting in temporary failure or permanent damage of the sensor performance.

[0039] Secondly, when the olfactory sensor is working, the heat generated by the electrical elements inside the cavity will cause the air inside the cavity to expand and the internal air pressure to rise, forcing the air to be discharged outward. When the olfactory sensor stops working and cools down, the internal air pressure decreases, and the external humid air is sucked into the shell. This cycle repeats, and each cycle will suck in the internal environment air rich in water vapor. In the case of day and night temperature difference or large environmental temperature change, the inhaled water vapor will condense into water droplets on the cooler shell inside or the sensor surface. This process will continuously accumulate moisture, causing the sensor response to be distorted, the sensitivity to be irreversibly attenuated, and ultimately greatly shortening the service life of the olfactory sensor.

[0040] Therefore, the olfactory sensor lacking water vapor protection has technical problems of easy water vapor invasion, performance degradation, and short service life, which restricts its reliability and durability in real environments such as outdoor, industrial field, kitchen, and the like which are humid, dusty, or have large temperature difference.

[0041] To solve the technical problems of easy water vapor invasion into the olfactory sensor, low detection accuracy, and high failure rate, an embodiment of the present application provides an olfactory sensor 100.

[0042] Reference Figure 1 , Figure 2 and Figure 3 , Figure 1 is a structural schematic diagram of the high-humidity-resistant MEMS-based olfactory sensor 100 of the embodiment of the present application; Figure 2 is an exploded view of the high-humidity-resistant MEMS-based olfactory sensor 100 of the embodiment of the present application; Figure 3 is an exploded view of the high-humidity-resistant MEMS-based olfactory sensor 100 of the embodiment of the present application. The high-humidity-resistant MEMS-based olfactory sensor 100 of the embodiment of the present application comprises a shell 1, the shell 1 comprising an air inlet 11; a gas detection assembly 2 arranged in the shell 1; and a filter assembly 3 arranged on a side of the gas detection assembly 2 facing the air inlet 11, the filter assembly 3 comprising a waterproof air-permeable film 31.

[0043] The shell 1 refers to a structural member for accommodating and protecting internal electronic components. The shell 1 is provided with the air inlet 11, which communicates the inside and outside of the shell 1, and is a channel for the to-be-detected gas to enter the interior of the device.

[0044] The gas detection assembly 2 detects air through the sensor contained therein. In the working process, the to-be-detected gas enters the shell 1 from the air inlet 11 and diffuses to the gas detection assembly 2. After the plurality of MEMS gas sensitive elements 221 on the gas detection assembly 2 interact with gas molecules, a change in electrical parameters such as resistance or capacitance is generated. This change is collected by the microprocessor 23 in real time as a response signal, and through analysis and identification, the odor information is ultimately obtained.

[0045] The filter assembly 3 is a barrier structure located between the air inlet 11 and the gas detection assembly 2, and the core thereof comprises the waterproof air-permeable film 31. The waterproof air-permeable film 31 is a special polymer film with a microporous structure. The size of these micropores allows gas molecules to pass freely, but can block liquid water and water vapor, and can also block pollutant particles.

[0046] The filter assembly 3 is arranged on a side of the gas detection assembly 2 facing the air inlet 11, which indicates that the filter assembly 3 is in a front position relationship in the gas flow path. The to-be-detected gas must pass through the filter assembly 3 first, and then reach the gas detection assembly 2 behind.

[0047] After passing through the gas inlet 11, the to-be-detected gas first reaches the filter assembly 3. The waterproof and breathable film 31 performs a filtering function by virtue of its microporous characteristics, blocking water vapor and pollutant particles mixed in the to-be-detected gas, and achieving pretreatment of the to-be-detected gas. The to-be-detected gas that has been pretreated and becomes dry and clean diffuses to the gas detection assembly 2, so that the gas detection assembly 2 can stably work in a dry and clean environment, so that the gas detection assembly 2 only responds to target gas molecules, avoiding performance degradation and physical damage caused by water condensation and pollution.

[0048] In summary, the application adds a filter assembly 3 with a waterproof and breathable film 31 as the core between the gas detection assembly 2 and the gas inlet 11, and constructs an effective physical barrier. The physical barrier solves the technical problems of sensor precision decline, poor reliability and short service life caused by water vapor and pollutants in the prior art, and achieves the technical effects of improving the environmental adaptability and long-term working stability of the high-humidity-resistant MEMS-based olfactory sensor 100 in a complex humid environment.

[0049] In the application, the "high-humidity scenario" corresponding to the high-humidity-resistant MEMS-based olfactory sensor 100 refers to an application environment with a relative humidity (RH) of not less than 80% RH. The preferred application humidity range is 80% RH to 100% RH.

[0050] 80% RH is selected as the lower limit of the "high-humidity scenario", mainly based on the following technical considerations:

[0051] 1. Inflection point of sensor performance degradation: When the environmental humidity is continuously higher than 80% RH, a significant multi-molecular water layer will form on the surface of the sensitive material. This water film will hinder the effective contact between the to-be-detected gas molecules and the sensitive material, and cause baseline drift and sensitivity decline. 80% RH is generally recognized as the critical point of such accelerated performance degradation.

[0052] 2. Condensation risk threshold: 80% RH is a threshold for high-humidity environments. When the ambient temperature drops slightly (such as night cooling or equipment entering an air-conditioned room from outdoors), air above 80% RH is likely to reach the dew point temperature, resulting in condensation. The liquid water formed by condensation is a direct cause of sensor short circuit, corrosion and permanent damage. Therefore, 80% RH is an important early warning line to prevent condensation and ensure long-term reliability of the equipment.

[0053] 3. Coverage of actual applications: Many typical scenarios that require high-reliability gas detection have humidity normal or peak values exceeding 80% RH. For example:

[0054] Kitchen environment: The humidity during cooking can reach more than 80% RH.

[0055] Bathroom: humidity during bathing often exceeds 90% RH.

[0056] Food processing plant, brewery: production workshop humidity control at high level.

[0057] Outdoor humid climate: rainy season, coastal areas or humidity often maintained at 80%-100% RH in the morning.

[0058] Basement, warehouse: poor ventilation of humid space.

[0059] Setting the lower limit to 80% RH can ensure that your patent protection range covers these real and demanding application scenarios.

[0060] The upper limit of 100% RH is the theoretical saturation humidity limit, representing the most extreme case of condensation that may occur. Explicitly including 100% RH means that the technical solution (such as the waterproof breathable film) of the present application can still provide effective protection even in conditions of saturated water vapor or short-term risk of liquid water.

[0061] Referring to Figure 1 , Figure 2 and Figure 3 , in some embodiments of the present application, the filter assembly 3 further comprises an activated carbon layer 32, which is arranged between the gas detection assembly 2 and the air inlet 11.

[0062] In some embodiments of the present application, the waterproof breathable film 31 is prepared by expanding polytetrafluoroethylene material, and the activated carbon layer 32 includes iodide and / or metal oxide.

[0063] In this embodiment, the activated carbon can adsorb interfering gases in the air that affect the detection results and detection accuracy, achieving pre-treatment of the air.

[0064] Specifically, the activated carbon layer 32 has a pore structure inside, which provides enough attachment points for gas molecules. When gas molecules pass through these pores, they will be captured and temporarily stay on the surface by the weak electrostatic attraction between the pore surface and the molecules.

[0065] In an alternative embodiment, the activated carbon can be impregnated with carbon treatment, or loaded with chemical substances such as iodide and metal oxide in the activated carbon layer 32, so that the activated carbon layer 32 can chemically react with specific gas molecules, thereby achieving filtering and screening of interfering gases.

[0066] For example, activated carbon impregnated with potassium iodide can more effectively adsorb hydrogen sulfide and other acidic gases.

[0067] Therefore, by arranging the activated carbon layer 32, on the one hand, the MEMS gas sensitive element 221 can be prevented from being contaminated by the interfering gas in the air, thereby prolonging the service life of the MEMS gas sensitive element 221, and on the other hand, the interference of the interfering gas on the detection result and the detection accuracy can be reduced, thereby improving the reliability of the high-humidity-resistant MEMS-based olfactory sensor 100.

[0068] The waterproof and breathable film 31 is prepared based on an expanded polytetrafluoroethylene material, which has micron or nanometer level network intercommunication micropores. The sizes of the micropores are larger than those of air molecules but smaller than those of water droplets, thereby achieving the effect of allowing air molecules to pass freely and effectively blocking liquid water.

[0069] Referring to Figure 1 , Figure 2 and Figure 3 In some embodiments of the present application, the filter assembly 3 includes at least two waterproof and breathable films 31, which are distributed in the axial direction of the air inlet 11.

[0070] In this embodiment, two waterproof and breathable films 31 are arranged between the air inlet 11 and the gas detection assembly 2, so that the to-be-detected gas needs to pass through the composite barrier composed of at least two waterproof and breathable films 31 in sequence after passing through the air inlet 11 to reach the rear gas detection assembly 2. Each waterproof and breathable film 31 is composed of a hydrophobic material with a microporous structure and can effectively block water vapor and allow gas to pass through.

[0071] By adopting the axial superposition distribution of multiple waterproof and breathable films 31, the high-humidity-resistant MEMS-based olfactory sensor 100 is provided with redundant protection, that is, even in the extreme case that the outermost waterproof and breathable film 31 is partially disabled due to physical scratching or chemical contamination, the inner waterproof and breathable film 31 can still serve as a reliable backup barrier to continuously and effectively block the invasion of water vapor, thereby reducing the risk of failure of the entire filter assembly 3 due to a single point failure, improving the reliability of the high-humidity-resistant MEMS-based olfactory sensor 100, and prolonging the service life of the high-humidity-resistant MEMS-based olfactory sensor 100.

[0072] On this basis, the at least two waterproof and breathable films 31 can realize graded filtration and optimize the protection effect. Waterproof and breathable films 31 with different performance specifications can be combined for use to realize functional division and graded filtration. For example, the outer waterproof and breathable film 31 is selected to have a slightly larger pore size, higher mechanical strength, and better resistance to pollution, mainly responsible for blocking large-particle dust and direct water splash impact, and the inner waterproof and breathable film 31 is selected to have a smaller pore size and better water resistance, focusing on blocking finer water mist, thereby strengthening the water vapor protection performance of the filter assembly 3.

[0073] Referring to Figure 1 , Figure 2and Figure 3 In some embodiments of the present application, the filter assembly 3 further comprises a support 33 arranged between the gas detection assembly 2 and the air inlet 11, and the waterproof and breathable membrane 31 is arranged on the support 33, and the support 33 is used to support the waterproof and breathable membrane 31.

[0074] In this embodiment, the support 33 is arranged between the gas detection assembly 2 and the air inlet 11, and the support 33 is a rigid or semi-rigid structure with through holes, and the waterproof and breathable membrane 31 is fixed to one side of the support 33 or embedded in the inside of the support 33 by means such as hot melting, gluing or mechanical pressing.

[0075] The main function of the support 33 is to provide physical support for the waterproof and breathable membrane 31 which has relatively weak mechanical strength. Specifically, the rigid structure of the support 33 can effectively resist the impact caused by external accidental collision or pressing, prevent the soft waterproof and breathable membrane 31 from being depressed, broken or falling off from the installation position due to stress, ensure the air tightness of the connection between the filter assembly 3 and the shell 1, eliminate the leakage of water vapor from the edge of the waterproof and breathable membrane 31, and improve the sealing reliability of the waterproof and breathable membrane 31 to water vapor.

[0076] In addition, when there is a large air pressure difference between the inside and outside of the shell 1, or when the waterproof and breathable membrane 31 is wet and heavy due to the adsorption of water vapor and pollutants, the waterproof and breathable membrane 31 is prone to deformation and even blockage of the micropores. The support 33 provides support for the waterproof and breathable membrane 31, enhances the pressure difference resistance of the waterproof and breathable membrane 31, and can prevent the waterproof and breathable membrane 31 from collapsing or the air permeation channel from being blocked, thereby improving the reliability and stability of the waterproof and breathable membrane 31.

[0077] In addition, the waterproof and breathable membrane 31 can be pre-integrated on the support 33 to form an independent module. As a whole component, this module facilitates subsequent automated assembly and precise positioning with the shell 1, reducing the risk of damaging the waterproof and breathable membrane 31 during assembly. At the same time, if replacement or maintenance is required, the entire module can be replaced directly, simplifying the production and maintenance process and improving production efficiency and product consistency.

[0078] Referring to Figure 1 , Figure 2 and Figure 3 In some embodiments of the present application, when the filter assembly 3 comprises at least two layers of waterproof and breathable membranes 31, the support 33 and the waterproof and breathable membrane 31 correspond one by one, and in the axial direction of the air inlet 11, the support 33 and the waterproof and breathable membrane 31 are arranged alternately.

[0079] In this embodiment, by inserting a support 33 between every two adjacent layers of waterproof and breathable membranes 31, an alternating laminated structure of "waterproof and breathable membrane 31-support 33-waterproof and breathable membrane 31-support 33" is formed.

[0080] The structure can configure a rigid support 33 for each layer of soft and vulnerable waterproof and breathable film 31, so that each layer of waterproof and breathable film 31 can obtain reliable support. Thus, under pressure, the multiple layers of waterproof and breathable film 31 are prevented from being pressed against each other, and the waterproof and breathable film 31 is prevented from being wrinkled, deformed or microporous blocked due to pressing, thereby achieving the technical effects of improving the stability and reliability of the waterproof and breathable film 31 and reducing the failure rate of the waterproof and breathable film 31.

[0081] Referring to Figure 1 , Figure 2 and Figure 3 , in some embodiments of the present application, the support 33 includes a metal mesh 331 and a support ring 332, the support ring 332 abuts the gas detection assembly 2 or the adjacent waterproof and breathable film 31, the metal mesh 331 is arranged on one side of the support ring 332 close to the air inlet 11, and the waterproof and breathable film 31 is laid on the metal mesh 331.

[0082] The support ring 332 is a ring-shaped rigid frame structure with a central through hole, which can be made of plastic, metal or other rigid materials by injection molding or machining. Its function is to build an installation skeleton. One side end surface of the support ring 332 abuts the surface of the shell 1 of the gas detection assembly 2 or the adjacent waterproof and breathable film 31 / support 33, thereby determining the installation position of the entire filter assembly 3 in the axial direction and providing axial support.

[0083] The metal mesh 331 is a porous mesh sheet woven by metal wires, and the metal mesh 331 is fixed on the end surface of the support ring 332 close to the air inlet 11. The mesh size of the metal mesh 331 is larger than the micropore size of the waterproof and breathable film 31, and the metal mesh 331 can provide a flat, solid and breathable attachment base for the waterproof and breathable film 31.

[0084] After assembly is completed, the support ring 332 serves as a base frame, the metal mesh 331 is attached thereto, and finally the waterproof and breathable film 31 is covered on the outer surface of the metal mesh 331 and fixed by heat pressing or gluing.

[0085] By arranging the metal mesh 331 and the support ring 332, effective support can be provided for the waterproof and breathable film 31, the deformation of the waterproof and breathable film 31 is prevented, the local pressure caused by gas pressure, water flow impact or external touch is dispersed, the risk of deformation and collapse of the waterproof and breathable film 31 at the micropore is reduced, and the technical effects of improving the reliability of the waterproof and breathable film 31 and prolonging the service life of the waterproof and breathable film 31 are achieved.

[0086] Referring to Figure 1 , Figure 2 and Figure 3In some embodiments of the present application, the filter assembly 3 comprises two waterproof and breathable membranes 31 and one activated carbon layer 32, and the activated carbon layer 32 is arranged between the two waterproof and breathable membranes 31.

[0087] In this embodiment, the filter assembly 3 comprises two waterproof and breathable membranes 31 and one activated carbon layer 32, and the activated carbon layer 32 is arranged between the two waterproof and breathable membranes 31. The structure realizes the synergy of physical and chemical filtration through the order and function of each layer of material, and provides all-round protection.

[0088] Specifically, the first waterproof and breathable membrane 31 close to the air inlet 11 first performs primary physical filtration on the inhaled gas to be detected, effectively blocking macroscopic pollutants such as water vapor, large particle dust, suspended matter, etc., and creating a relatively dry and clean environment for the activated carbon layer 32 behind.

[0089] The activated carbon layer 32 in the middle further absorbs the gas to be detected after primary filtration, specifically absorbing volatile organic compounds, odor molecules and part of chemical gaseous pollutants that penetrate the first waterproof and breathable membrane 31.

[0090] The second waterproof and breathable membrane 31 close to the gas detection assembly 2 performs final physical filtration, which can further reduce the possibility of water vapor contacting the gas detection assembly 2, and can prevent the activated carbon powder or particles falling off from the activated carbon layer 32 from contacting the gas detection assembly 2, thereby avoiding the pollution of the MEMS gas sensitive element 221 by the activated carbon powder or particles, and achieving the technical effects of improving the reliability of the gas detection assembly 2, improving the detection accuracy of the gas detection assembly 2, and prolonging the service life of the gas detection assembly 2.

[0091] Referring to Figure 4 , Figure 4 The structure of the gas detection assembly 2 of the high-humidity-resistant MEMS-based olfactory sensor 100 of the present application is shown in the figure. In some embodiments of the present application, the gas detection assembly 2 comprises a circuit board 21, a MEMS gas sensor array 22 and a microprocessor 23, the circuit board 21 is arranged in the shell 1, the MEMS gas sensor array 22 comprises a plurality of MEMS gas sensitive elements 221, the MEMS gas sensitive elements 221 have cross-sensitivity to target gas, the MEMS gas sensitive elements 221 are integrated on the circuit board 21 in a surface mounting manner, and the microprocessor 23 is connected with the circuit board 21, used for collecting response signals of the plurality of MEMS gas sensitive elements 221, and performing data processing and pattern recognition on the response signals, and outputting gas concentration data and recognition results.

[0092] In this embodiment, the circuit board 21 is installed in the shell 1, and the circuit board 21 is a substrate for installing and electrically connecting electronic components.

[0093] The MEMS gas sensor array 22 refers to a micro sensor that integrates mechanical components, sensor devices and electronic circuits on the same chip by using semiconductor microfabrication technology. The plurality of MEMS gas sensitive elements 221 contained therein refer to a plurality of micro units sensitive to gas, which are made of different sensitive materials, thereby having cross-sensitivity to a plurality of target gases, i.e., each element responds to a plurality of gases but with different sensitivities.

[0094] The MEMS gas sensitive element 221 is integrated on the circuit board 21 in a surface mounting manner, i.e., the MEMS gas sensitive element 221 is directly mounted and welded on the pad on the surface of the circuit board 21 with its bottom pad, without the need for pin perforation.

[0095] The microprocessor 23 is an integrated computing control unit, which is electrically connected to the MEMS gas sensor array 22 through the wires on the circuit board 21, and is configured to collect response signals corresponding to the electrical changes of each MEMS gas sensitive element 221 and perform data processing and pattern recognition, wherein the data processing and pattern recognition are analysis of the collected multi-dimensional signals, and finally output the identification result of the gas species or concentration, thereby realizing the odor recognition function.

[0096] During operation, the gas to be detected enters the shell 1 from the gas inlet 11 and diffuses to the MEMS gas sensor array 22, and the plurality of MEMS gas sensitive elements 221 thereon interact with gas molecules to produce changes in electrical parameters such as resistance or capacitance. The change is collected as a response signal by the microprocessor 23 in real time, and through analysis and identification, the odor information is finally obtained.

[0097] The present application solves the problem of the size of the sensing element by using the MEMS gas sensor array 22, because the micro-electro-mechanical system technology can manufacture micron-scale sensitive structures at the chip level. Then, by being integrated on the circuit board 21 in a surface mounting manner, the pin-type packaging in the related art is abolished, the space occupied by the plug-in hole is eliminated, the installation height and occupied area of the sensor on the circuit board 21 are reduced, the height of the entire gas detection assembly 2 is flattened, and convenient conditions are provided for the light and thin design of the high-humidity-resistant MEMS-based olfactory sensor 100.

[0098] Therefore, by adopting the MEMS gas sensor array 22 and adopting the surface mounting method, the integration of the gas detection assembly 2 is improved, thereby reducing the need for external wiring and external control units, providing convenient conditions for the miniaturization design and lightweight design of the high-humidity-resistant MEMS-based olfactory sensor 100, so that the high-humidity-resistant MEMS-based olfactory sensor 100 can be applied in many portable scenarios, for example, the high-humidity-resistant MEMS-based olfactory sensor 100 can be arranged on a handheld device, or the high-humidity-resistant MEMS-based olfactory sensor 100 can be integrated on a security inspection device, thereby realizing the technical effects of reducing the size of the high-humidity-resistant MEMS-based olfactory sensor 100 and widening the application scenarios of the high-humidity-resistant MEMS-based olfactory sensor 100.

[0099] In a specific application scenario, the high-humidity-resistant MEMS-based olfactory sensor 100 is used to detect target gases in the air, and the target gases include toxic and harmful gases such as nitrogen, methane, carbon monoxide, hydrogen sulfide, and hydrogen cyanide.

[0100] Referring to Figure 4 In some embodiments of the present application, the MEMS gas sensitive element 221 is a metal oxide semiconductor gas sensor, and the MEMS gas sensitive element 221 is packaged in a grid array form.

[0101] In this embodiment, the sensitive material of the metal oxide semiconductor gas sensor is a metal oxide (such as a semiconductor material such as tin dioxide SnO2 and tungsten oxide WO3). During the detection process, under the action of the micro-heating plate prepared by the micro-electro-mechanical system technology, the sensitive material is heated to a predetermined working temperature. When the target gas molecules come into contact with the surface of the sensitive metal oxide, a chemical reaction occurs, which causes the resistance value of the metal oxide film to change. The resistance change amount is related to the gas concentration and can be collected as a response signal by the microprocessor 23.

[0102] The present application further improves the integration of the internal structure of the shell 1 by combining the metal oxide semiconductor gas sensor with the micro-electro-mechanical system manufacturing process.

[0103] The grid array (Land Grid Array, LGA) form packaging has no pins at the bottom of the package, and the bottom of the package forms pads. During installation, the pads are directly mounted and soldered to the corresponding solder points on the surface of the circuit board 21.

[0104] The grid array form packaging eliminates the space occupied by the pins in the horizontal and vertical directions, and the pinless feature provides convenient conditions for the miniaturization design and lightweight design of the high-humidity-resistant MEMS-based olfactory sensor 100.

[0105] In addition, the grid array form package is suitable for high-precision chip mounters to quickly and accurately pick up and mount, facilitating large-scale and high-consistency batch production, so that the high-humidity-resistant MEMS-based olfactory sensor 100 can be produced in a low-cost and high-efficiency manner.

[0106] With reference to Figure 4 In some embodiments of the present application, the circuit board 21 comprises a first circuit board 211 and a second circuit board 214 electrically connected, the first circuit board 211 and the second circuit board 214 are distributed along the first direction X, the MEMS gas sensor array 22 is arranged on the first circuit board 211, and the microprocessor 23 is arranged on the second circuit board 214, and the second circuit board 214 is provided with pins 215 on the side away from the first circuit board 211.

[0107] In this embodiment, the circuit board 21 comprises at least one first circuit board 211 and one second circuit board 214, the first circuit board 211 is used to arrange the MEMS gas sensor array 22, and the second circuit board 214 is used to arrange the microprocessor 23 and the power supply element of the high-humidity-resistant MEMS-based olfactory sensor 100.

[0108] In the case where the number of the first circuit boards 211 is one, the plurality of MEMS gas sensitive elements 221 in the MEMS gas sensor array 22 are distributed on the same first circuit board 211, and in the case where the number of the first circuit boards 211 is multiple, the plurality of MEMS gas sensitive elements 221 are distributed on the multiple first circuit boards 211, and at least one MEMS gas sensitive element 221 is arranged on each first circuit board 211.

[0109] Specifically, the first circuit board 211 and the second circuit board 214 are spaced apart and distributed in the first direction X, and the first direction X corresponds to the height direction of the high-humidity-resistant MEMS-based olfactory sensor 100, for example, when the high-humidity-resistant MEMS-based olfactory sensor 100 is in the form of a column as a whole, the first direction X corresponds to the axial direction of the high-humidity-resistant MEMS-based olfactory sensor 100.

[0110] Therefore, by independently distributing the MEMS gas sensitive elements 221 on the first circuit board 211, the MEMS gas sensitive elements 221 can be separated from the microprocessor 23, the power supply element and other electrical elements, so that the heat generated by the microprocessor 23, the power supply element and other electrical elements can be prevented from being directly transmitted to the MEMS gas sensitive elements 221 through the circuit board 21, thereby reducing the interference of the microprocessor 23, the power supply element and other electrical elements on the MEMS gas sensitive elements 221, and achieving the technical effect of improving the detection accuracy of the MEMS gas sensitive elements 221.

[0111] And, the application realizes the multi-layer architecture of the circuit board 21 by distributing the first circuit board 211 and the second circuit board 214 along the first direction X, so that the electrical components in the high-humidity-resistant MEMS-based olfactory sensor 100 can be arranged in the first direction X, compared with the scheme of arranging all the electrical components on the same circuit board 21, the application can reasonably utilize the longitudinal space in the shell 1, thereby improving the integration of the high-humidity-resistant MEMS-based olfactory sensor 100, providing convenient conditions for the miniaturization design of the high-humidity-resistant MEMS-based olfactory sensor 100, and then realizing the technical effects of reducing the size of the high-humidity-resistant MEMS-based olfactory sensor 100 and widening the application scenarios of the high-humidity-resistant MEMS-based olfactory sensor 100.

[0112] The second circuit board 214 is provided with pins 215 protruding from the side of the second circuit board 214 away from the first circuit board 211, and the pins 215 are used for electrical connection with associated equipment, so that the gas detection result can be transmitted to the associated equipment through the pins 215, thereby realizing the technical effect of widening the application scenarios of the gas detection assembly 2.

[0113] The above is only a specific embodiment of the application, enabling those skilled in the art to understand or implement the application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the application. Therefore, the application will not be limited to these embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A MEMS-based olfactory sensor resistant to high humidity, characterized in that, include: A housing, the housing including an air inlet; A gas detection component is disposed within the housing; A filter assembly is disposed on the side of the gas detection assembly facing the air inlet, and the filter assembly includes a waterproof and breathable membrane and an activated carbon layer; The activated carbon layer is disposed between the gas detection component and the waterproof and breathable membrane; The waterproof and breathable membrane is a polymer film with a microporous structure.

2. The high-humidity resistant MEMS-based olfactory sensor as described in claim 1, characterized in that, The waterproof and breathable membrane is made of expanded polytetrafluoroethylene material, and the activated carbon layer includes iodides and / or metal oxides.

3. The high-humidity resistant MEMS-based olfactory sensor as described in claim 1, characterized in that, The filter assembly includes at least two layers of the waterproof and breathable membrane, which are distributed axially along the air inlet.

4. The high-humidity resistant MEMS-based olfactory sensor as described in claim 1, characterized in that, The filter assembly further includes a support member disposed between the gas detection assembly and the air inlet, and the waterproof and breathable membrane is disposed on the support member, which is used to support the waterproof and breathable membrane.

5. The high-humidity resistant MEMS-based olfactory sensor as described in claim 4, characterized in that, When the filter assembly includes at least two layers of the waterproof and breathable membrane, the support member and the waterproof and breathable membrane correspond one-to-one, and the support member and the waterproof and breathable membrane are alternately arranged in the axial direction of the air inlet.

6. The high-humidity resistant MEMS-based olfactory sensor as described in claim 4, characterized in that, The support member includes a metal mesh and a support ring. The support ring abuts against the gas detection component or the adjacent waterproof and breathable membrane. The metal mesh is located on the side of the support ring near the air inlet, and the waterproof and breathable membrane is laid on the metal mesh.

7. The high-humidity resistant MEMS-based olfactory sensor as described in any one of claims 1 to 5, characterized in that, The filter assembly includes two waterproof and breathable membranes and an activated carbon layer, with the activated carbon layer located between the two waterproof and breathable membranes.

8. The high-humidity resistant MEMS-based olfactory sensor as described in any one of claims 1 to 5, characterized in that, The gas detection component includes a circuit board, a MEMS gas sensor array, and a microprocessor. The circuit board is disposed within the housing. The MEMS gas sensor array includes multiple MEMS gas sensing elements, which have cross-sensitivity to the target gas. The MEMS gas sensing elements are integrated onto the circuit board via surface mounting. The microprocessor is connected to the circuit board and is used to acquire the response signals of the multiple MEMS gas sensing elements, perform data processing and pattern recognition on the response signals, and output gas concentration data and recognition results.

9. The high-humidity resistant MEMS-based olfactory sensor as described in claim 8, characterized in that, The MEMS gas sensing element is a metal oxide semiconductor gas sensor, and the MEMS gas sensing element is packaged in the form of a grid array.

10. The high-humidity resistant MEMS-based olfactory sensor as described in claim 8, characterized in that, The circuit board includes a first circuit board and a second circuit board that are electrically connected. The first circuit board and the second circuit board are distributed along a first direction. The MEMS gas sensor array is disposed on the first circuit board, and the microprocessor is disposed on the second circuit board. Pins are provided on the side of the second circuit board facing away from the first circuit board.

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