Photoacoustic spectroscopy multi-gas MEMS micro gas sensor

Abstract

This invention discloses a photoacoustic spectroscopy-based multi-gas MEMS miniature gas sensor, comprising a packaged shell. An integrated circuit chip, a MEMS infrared light source, and a MEMS pressure sensor are respectively disposed within the cavity of the packaged shell. The integrated circuit chip, MEMS infrared light source, and MEMS pressure sensor are electrically connected. The integrated circuit chip controls the operating state of the MEMS infrared light source and reads the output signal of the MEMS pressure sensor. The MEMS infrared light source converts the electrical signal into an optical signal, and the MEMS pressure sensor converts the acoustic signal into an electrical signal. This invention has advantages such as small size, low cost, high accuracy, and good reliability, and can realize real-time monitoring of multiple gases, showing promising application prospects.

Description

Technical Field

[0001] This invention belongs to the field of sensor technology, specifically relating to a photoacoustic spectroscopy-based multi-gas MEMS miniature gas sensor. Background Technology

[0002] Photoacoustic spectroscopy is a highly sensitive method for detecting trace gases. It calculates the concentration of a gas by measuring the acoustic signal generated by the absorption of light waves of a specific wavelength. Therefore, it has the advantages of low background noise, fast response speed and good gas selectivity, and has broad application prospects in industrial gas emission monitoring, atmospheric environment monitoring and indoor air quality monitoring.

[0003] Current photoacoustic spectroscopy gas sensing systems mostly employ expensive, high-performance laser sources, sophisticated optical path designs, and large-volume photoacoustic cells. Examples include the use of multiple distributed feedback lasers and ultra-high-frequency lock-in amplifiers, high-power tunable diode lasers, concave mirror dual-path optical path designs, and dual-cavity photoacoustic cell designs. All these approaches result in high cost, large size, and complex structure, severely limiting their large-scale application. Regarding integration and miniaturization, existing solutions propose integrated designs for components such as lasers, optical lenses, photodetectors, and acousto-optic conversion circuits, but the system size remains in the tens of centimeters range. There are also photoacoustic spectroscopy gas sensors based on a combination of optical fibers and silicon cantilever beams. While these solutions reduce the size of the sensing head to the centimeter level, they still inevitably use complex optical paths and expensive lasers. A new type of miniaturized MEMS photoacoustic spectroscopy gas sensor has been proposed abroad. Although it solves the size and cost issues, it cannot simultaneously sense multiple gas components and is limited by its packaging structure, making it unsuitable for harsh industrial environments.

[0004] In multi-gas component sensing, a common approach is to encapsulate a microphone within a sealed cavity filled with the target gas, placing a MEMS infrared light source outside the cavity. The presence of the target gas in the absorption path reduces the photoacoustic signal generated within the sealed cavity. However, this approach not only diminishes the low background noise advantage of photoacoustic spectroscopy but also increases the manufacturing cost of the sealed enclosure. Furthermore, gas leakage can lead to long-term performance drift in the sensor. Adjusting the light source wavelength to achieve multi-gas component sensitivity is another approach, introducing multi-wavelength tunable laser arrays or stacked filters to switch the light source wavelength. However, existing methods rely on complex control systems and sophisticated optical path and structural designs, making them unsuitable for large-scale applications. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a photoacoustic spectroscopy multi-gas MEMS micro gas sensor to address the shortcomings of the prior art, thereby solving the technical problems that traditional solutions cannot simultaneously achieve accuracy, integration, cost and reliability, and realizing the simultaneous monitoring of multi-component gases.

[0006] The present invention adopts the following technical solution:

[0007] A photoacoustic spectroscopy-based multi-gas MEMS micro gas sensor includes a packaged shell. An integrated circuit chip, a MEMS infrared light source, and a MEMS pressure sensor are respectively disposed inside the cavity of the packaged shell. A packaged cover is disposed above the cavity of the packaged shell. The integrated circuit chip, the MEMS infrared light source, and the MEMS pressure sensor are electrically connected. The integrated circuit chip is used to control the working state of the MEMS infrared light source and read the output signal of the MEMS pressure sensor. The MEMS infrared light source is used to convert electrical signals into optical signals, and the MEMS pressure sensor is used to convert acoustic signals into electrical signals.

[0008] Specifically, the MEMS infrared light source integrates a narrow-bandwidth filter, the wavelength λ of which is consistent with the infrared absorption peak wavelength of the gas to be measured.

[0009] Specifically, the cavity depth is less than 2 cm, and the cavity bottom area is less than 4 cm². 2 .

[0010] Specifically, the package type is surface mount or through-hole.

[0011] Specifically, the encapsulation cover is made of metal, ceramic, or quartz.

[0012] Specifically, the encapsulation cover is sealed to the encapsulation shell by bonding, adhesive bonding, or welding.

[0013] Furthermore, the encapsulation cover is provided with vent holes, which are covered with a breathable membrane.

[0014] Furthermore, the breathable membrane has a pore size of 30nm to 1μm and an air permeability of 100 to 10000ml / cm². 2 / min@7kPa.

[0015] Furthermore, the encapsulation cover is provided with a micro-through hole structure.

[0016] Specifically, the integrated circuit chip includes at least two chips: one integrated circuit chip is used to control the time-division operation of multiple MEMS infrared light sources, and the other integrated circuit chip is used to control the signal detection of the MEMS pressure sensor.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects:

[0018] This invention discloses a photoacoustic spectroscopy-based multi-gas MEMS miniature gas sensor. It replaces the laser in traditional photoacoustic spectroscopy sensing systems with a MEMS infrared light source, replaces the traditional condenser microphone with a MEMS pressure sensor, and replaces the traditional phase-locked loop and oscilloscope with a micro-integrated circuit chip. This significantly reduces the size and cost of the sensing system. The various modules of the sensor are electrically connected using ultrasonic gold wire bonding technology. The MEMS light source generates infrared light waves, causing gas molecules to emit photoacoustic signals, and the gas concentration is determined by the intensity of these signals. Compared to traditional photoacoustic spectroscopy systems, this invention offers advantages such as higher integration, better accuracy, and superior reliability. In terms of integration, the device manufactured using MEMS technology has the inherent advantages of smaller size and lighter weight, and has a wider range of applications compared to traditional desktop optical systems. In terms of accuracy, since the photoacoustic signal is inversely proportional to the volume of the photoacoustic cell, the miniature photoacoustic cell of this invention enables the sensor to not only have a higher signal amplitude but also a faster response speed. In terms of reliability, due to the use of industrial-grade integrated packaging, this invention reduces the electrical noise that may be introduced and is not affected by environmental noise such as vibration and electromagnetic fields, resulting in higher reliability and stability.

[0019] Furthermore, the MEMS infrared light source integrates a narrow-bandwidth filter, which can convert the originally generated 2-20μm broadband infrared light into narrow-bandwidth infrared light with a specific wavelength, thereby realizing the detection of specific gases. Specifically, the integrated circuit chip generates a periodic voltage signal with frequency f, which is transmitted to the MEMS infrared light source through gold wire bonding, controlling the MEMS infrared light source to generate infrared light. The intensity of this infrared light also varies periodically with frequency f and is further filtered by a narrow-bandwidth filter with a center wavelength λ. When gas molecules are irradiated with infrared radiation, they absorb infrared light of their respective characteristic wavelengths and generate heat energy through non-radiative transitions. Therefore, when the intensity of the infrared light varies periodically with frequency f, the gas inside the package will undergo periodic expansion, resulting in pressure fluctuations with frequency f. When λ is equal to the characteristic wavelength of the gas to be measured, the generated infrared light will only be absorbed by the molecules of the gas to be measured, and the amplitude of this pressure fluctuation will be positively correlated with the concentration of the gas to be measured.

[0020] Furthermore, the smaller the cavity, the greater the pressure fluctuation signal generated. In addition, since the integrated circuit chip, MEMS infrared light source, and MEMS pressure sensor used in this invention all have small dimensions, to ensure the overall integration and sensitivity of the sensor, the depth of the cavity in this invention is preferably less than 2 cm, and the bottom area of ​​the cavity is preferably less than 4 cm². 2 .

[0021] Furthermore, the packaging shell used in this invention is made of metal or ceramic, which improves its reliability under harsh working conditions; the packaging type is surface mount or through-hole type, which facilitates its embedded use.

[0022] Furthermore, the encapsulation cover is made of metal, ceramic, or quartz, which can achieve better electromagnetic and noise shielding, ensuring the reliability of the sensor under harsh operating conditions.

[0023] Furthermore, the encapsulation cover is sealed to the encapsulation shell by bonding, adhesive or welding to achieve better electromagnetic shielding and noise shielding, ensuring the reliability of the sensor under harsh operating conditions.

[0024] Furthermore, the encapsulation cover is equipped with vent holes to facilitate gas exchange between the inside and outside of the cavity, ensuring the sensor's timely response to the external gas environment. In addition, a microporous membrane is arranged on the vent holes. According to the Knudsen diffusion principle, this membrane not only ensures gas exchange between the inside and outside of the cavity but also prevents the rapid overflow of periodically expanding gas within the cavity, which could prevent the generation of a pressure signal.

[0025] Furthermore, this invention includes multiple MEMS infrared light sources and two integrated circuit chips. The multiple MEMS infrared light sources have different center wavelengths, each corresponding to the absorption wavelength of a different gas being measured, thereby enabling the monitoring of different gas concentrations. One integrated circuit chip is electrically connected to a MEMS pressure sensor and is dedicated to powering the MEMS pressure sensor, reading and amplifying the signal, and transmitting the measured data to the other integrated circuit chip. The other integrated circuit chip controls the time-division multiplexing of the multiple MEMS infrared light sources, ensuring that only one MEMS infrared light source is active at any given time. The measured pressure signal amplitude at this time can be used to retrieve the corresponding gas concentration. Each MEMS infrared light source operates for 1–15 seconds, thus ensuring continuous monitoring of multiple gases.

[0026] In summary, this invention has the advantages of small size, low cost, high precision, and high reliability, and can realize real-time monitoring of various gases, thus having broad application prospects.

[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0028] Figure 1 This is a three-dimensional schematic diagram of the structure of the present invention;

[0029] Figure 2 This is a schematic diagram of the encapsulation cover and the ventilation structure of the present invention;

[0030] Figure 3This is a top view schematic diagram of a typical structure of the present invention in the detection of single gas components;

[0031] Figure 4 This is a top view schematic diagram of a typical structure of the present invention in the detection of multiple gas components;

[0032] Figure 5 This is a schematic diagram of the time-division multiplexing signal for multi-component gas detection according to the present invention.

[0033] The components are: 1. Package housing; 2. Integrated circuit chip; 2-1. First integrated circuit chip; 2-2. Second integrated circuit chip; 3. MEMS infrared light source; 3-1. First MEMS infrared light source; 3-2. Second MEMS infrared light source; 3-3. Third MEMS infrared light source; 3-4. Fourth MEMS infrared light source; 4. MEMS pressure sensor; 5. Package cover plate; 6. Vent hole; 7. Vent membrane; 8. Micro-through hole structure. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "one side," "one end," and "one side," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0038] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0039] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0040] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0041] Please see Figure 1This invention discloses a photoacoustic spectroscopy-based multi-gas MEMS micro gas sensor, comprising a packaged shell 1, an integrated circuit chip 2, a MEMS infrared light source 3, and a MEMS pressure sensor 4. The integrated circuit chip 2, the MEMS infrared light source 3, and the MEMS pressure sensor 4 are fixed inside the packaged shell 1 by adhesive bonding. The integrated circuit chip 2 is electrically connected to the MEMS infrared light source 3 and the MEMS pressure sensor 4 by ultrasonic gold wire bonding technology. The integrated circuit chip 2 can realize the power supply, signal reading, and signal amplification of the MEMS pressure sensor 4, and provide a periodic voltage signal to the MEMS infrared light source 3 to control the MEMS infrared light source 3 to emit periodic infrared light waves.

[0042] The package 1 has a cavity capable of accommodating the integrated circuit chip 2, the MEMS infrared light source 3, and the MEMS pressure sensor 4. The cavity depth is greater than or equal to the height of the integrated circuit chip 2, the MEMS infrared light source 3, and the MEMS pressure sensor 4.

[0043] Preferably, the bottom area of ​​the cavity is greater than or equal to the sum of the areas of the integrated circuit chip 2, the MEMS infrared light source 3, and the MEMS pressure sensor 4.

[0044] Preferably, the depth of the cavity is less than 2 cm, and the bottom area of ​​the cavity is less than 4 cm². 2 .

[0045] The package housing 1 is made of metal, ceramic and plastic, and the package type is surface mount or through-hole type. Preferably, the number of pins is less than 44.

[0046] The integrated circuit chip 2 is used to control the working state of the MEMS infrared light source 3 and to read the output signal of the MEMS pressure sensor 4.

[0047] MEMS infrared light source 3 is used to convert electrical signals into optical signals. In some implementations, MEMS infrared light source 3 is a surface-treated MEMS silicon hot plate, which is subjected to a periodic voltage signal with frequency f during operation, causing its temperature to change periodically with frequency f, thereby radiating infrared light waves with periodically modulated intensity.

[0048] Preferably, the MEMS infrared light source 3 integrates a narrow-bandwidth filter to achieve infrared light output with a specific wavelength λ, which should be consistent with the infrared absorption peak wavelength of the gas to be measured.

[0049] MEMS pressure sensor 4 is used to convert acoustic signals into electrical signals, and it has particularly high sensitivity to acoustic signals at frequency f. In some implementations, MEMS pressure sensor 4 employs a MEMS microphone, piezoelectric element, or MEMS piezoresistive cantilever beam structure.

[0050] Please see Figure 2 The photoacoustic spectroscopy type multi-gas MEMS micro gas sensor of the present invention also includes an encapsulation cover plate 5. The projected area of ​​the encapsulation cover plate 5 falls within the projection of the encapsulation shell 1 and is outside the internal cavity of the encapsulation shell 1. The encapsulation cover plate 5 is made of metal, ceramic, quartz or other hard materials and is sealed to the encapsulation shell 1 by bonding, adhesive, welding or other methods.

[0051] In some implementations, the encapsulation cover 5 is also provided with vent holes 6 to realize gas exchange between the inside and outside of the cavity. The vent holes 6 are covered with a breathable membrane 7, which is made of porous polymer material or micro-processed hard material. The breathable membrane 7 is connected to the encapsulation cover 5 by means of bonding, bonding, welding or other methods.

[0052] Preferably, the pore size of the breathable membrane 7 is 30 nm to 1 μm, and the air permeability is 100 to 10000 ml / cm³. 2 / min@7kPa.

[0053] In other implementations, micro-through-hole structures 8 can be fabricated on the encapsulation cover 5. The pore size of the micro-through-hole structures 8 is 30 nm to 1 μm, and the air permeability is 100 to 10000 ml / cm². 2 / min@7kPa, to replace the function of vent 6 and vent membrane 7.

[0054] The working principle of the photoacoustic spectroscopy multi-gas MEMS miniature gas sensor of this invention is as follows:

[0055] When the MEMS infrared light source 3 emits infrared light waves with a center wavelength λ and an intensity that varies periodically with a period of f, if the gas to be measured is present in the environment, the gas molecules will absorb light energy, generate heat energy, and thus expand in volume, generating a photoacoustic signal with a frequency of f in the cavity of the encapsulated shell 1. This photoacoustic signal can be converted into an electrical signal by the MEMS pressure sensor 4, which is then read and recorded by the integrated circuit chip 2. By detecting the amplitude of the photoacoustic signal, the concentration of the gas to be measured in the current environment can be inferred.

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0057] Please see Figure 3 When detecting single-component gases, the integrated circuit chip 2, MEMS infrared light source 3, and MEMS pressure sensor 4 are arranged within the cavity of the packaged tube 1 as follows: Figure 2 As shown, the arrangement of the integrated circuit chip 2, the MEMS infrared light source 3, and the MEMS pressure sensor 4 has no impact on the overall performance of the device. The integrated circuit chip 2 is electrically connected to the MEMS infrared light source 3 and the MEMS pressure sensor 4 using ultrasonic gold wire bonding technology. When the gas to be measured is present in the external environment of the sensor, the gas molecules can freely diffuse into the cavity through the vent 6 and the vent membrane 7. Since the integrated circuit chip 2 controls the MEMS infrared light source 3 to emit periodic infrared light with a wavelength λ and a modulation frequency f, this infrared light is absorbed by the gas molecules to be measured in the cavity, generating a periodic pressure signal. This pressure signal is sensed by the MEMS pressure sensor 4 and converted into an electrical signal, which is transmitted to the integrated circuit chip 2. The concentration of the molecule to be measured is calculated through the pre-calibrated pressure amplitude-gas concentration curve in the integrated circuit chip 2.

[0058] Please see Figure 4When detecting multi-component gases, the photoacoustic spectroscopy multi-gas MEMS miniature gas sensor of this invention includes multiple integrated circuit chips and multiple MEMS infrared light sources with different wavelengths. For example, in an embodiment for simultaneous detection of four gases, the photoacoustic spectroscopy multi-gas MEMS miniature gas sensor includes a first integrated circuit chip 2-1, a second integrated circuit chip 2-2, a first MEMS infrared light source 3-1, a second MEMS infrared light source 3-2, a third MEMS infrared light source 3-3, and a fourth MEMS infrared light source 3-4. The multiple MEMS infrared light sources have different center wavelengths, corresponding to the absorption wavelengths of different gases to be measured, thereby realizing the monitoring of the concentration of different gases. One integrated circuit chip is electrically connected to a MEMS pressure sensor and is dedicated to powering the pressure sensor, reading the signal, and amplifying the signal, and transmitting the measured data to another integrated circuit chip. The other integrated circuit chip can control the time-division multiplexing of the multiple MEMS infrared light sources, ensuring that only one MEMS infrared light source is in working condition at any given time. The measured pressure signal amplitude can be used to invert the corresponding gas concentration. The working time of each MEMS infrared light source is 1 to 15 seconds, thereby ensuring continuous monitoring of multiple gases.

[0059] Please see Figure 5 In a typical operating cycle, the first MEMS infrared light source 3-1 first receives a power signal with frequency f and duration t1, and then emits an emission wavelength of λ. a An optical signal with intensity modulation frequency f is generated in the cavity. When the gas to be measured a is present in the cavity, some of the light energy is absorbed by the gas to be measured, and an acoustic signal with frequency f is generated in the cavity.

[0060] After time t2, the second MEMS infrared light source 3-2 is excited in the same way to generate a wavelength of λ. b The light signal is absorbed by the gas b to be tested, thereby generating an acoustic signal with a frequency of f.

[0061] The third MEMS infrared light source 3-3 and the fourth MEMS infrared light source 3-4, and so on;

[0062] Finally, the output signal 9-5 of the MEMS pressure sensor 4 includes four sinusoidal waveforms with different durations (t1), intervals (t2), periods (f), and amplitudes. The concentration of the gas to be measured can be inverted by the amplitude of each sinusoidal waveform.

[0063] In summary, this invention provides a photoacoustic spectroscopy-based multi-gas MEMS miniature gas sensor. Compared with traditional photoacoustic spectroscopy sensing systems, this invention adopts a MEMS infrared light source and MEMS pressure sensor solution, which have advantages in both size and cost. While achieving the lower limit of gas detection at the ppm and sub-ppm levels, the total cost is controlled at the hundred-yuan level. Compared with existing single-gas photoacoustic spectroscopy gas sensors, this technology adopts a time-division multiplexing technology scheme with multiple MEMS infrared light sources to achieve simultaneous sensitivity of multiple gas components.

[0064] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A photoacoustic spectroscopy-based multi-gas MEMS miniature gas sensor, characterized in that, The package includes a housing (1), and an integrated circuit chip (2), a MEMS infrared light source (3), and a MEMS pressure sensor (4) are respectively disposed inside the cavity of the housing (1). The cavity depth is less than 2 cm and the cavity bottom area is less than 4 cm². 2 A package cover plate (5) is provided above the cavity of the package shell (1). A micro-through hole structure (8) is provided on the package cover plate (5). The integrated circuit chip (2), the MEMS infrared light source (3) and the MEMS pressure sensor (4) are electrically connected. The integrated circuit chip (2) is used to control the working state of the MEMS infrared light source (3) and read the output signal of the MEMS pressure sensor (4). The MEMS infrared light source (3) is used to convert the electrical signal into an optical signal. The MEMS pressure sensor (4) is used to convert the acoustic signal into an electrical signal. The integrated circuit chip (2) includes at least two, one integrated circuit chip (2) is used to control the time-division operation of multiple MEMS infrared light sources (3), and the other integrated circuit chip (2) is used to control the signal detection of MEMS pressure sensor (4); One of the integrated circuit chips (2) is electrically connected to the MEMS pressure sensor (4) and is dedicated to powering the MEMS pressure sensor (4), reading the signal and amplifying the signal, and transmitting the measured data to another integrated circuit chip (2); the other integrated circuit chip (2) can control the time-division multiplexing of multiple MEMS infrared light sources (3) to ensure that only one MEMS infrared light source (3) is working at the same time. At this time, the measured pressure signal amplitude can be used to invert the corresponding gas concentration. The working time of each MEMS infrared light source (3) is 1~15 seconds, thereby ensuring continuous monitoring of multiple gases; The MEMS infrared light source (3) has a narrow-bandwidth filter integrated inside, and the wavelength λ of the narrow-bandwidth filter is consistent with the infrared absorption peak wavelength of the gas to be measured.

2. The photoacoustic spectroscopy multi-gas MEMS miniature gas sensor according to claim 1, characterized in that, The packaging type of the encapsulation housing (1) is surface mount or through-hole type.

3. The photoacoustic spectroscopy multi-gas MEMS miniature gas sensor according to claim 1, characterized in that, The encapsulation cover (5) is made of metal, ceramic or quartz.

4. The photoacoustic spectroscopy multi-gas MEMS miniature gas sensor according to claim 1, characterized in that, The encapsulation cover (5) is sealed to the encapsulation shell (1) by bonding, adhesive or welding.

5. The photoacoustic spectroscopy multi-gas MEMS miniature gas sensor according to claim 4, characterized in that, The encapsulation cover (5) is provided with a vent hole (6), and the vent hole (6) is covered with a vent membrane (7).

6. The photoacoustic spectroscopy multi-gas MEMS miniature gas sensor according to claim 5, characterized in that, The pore size of the breathable membrane (7) is 30nm~1μm, and the air permeability is 100~10000ml / cm2 / min@7kPa.

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