Gas detection device and gas type and concentration detection method

Abstract

The invention belongs to the technical field of gas detection, and provides a gas detection device and a gas type and concentration detection method, the gas detection device comprises a gas detection module, a light source and a gas chamber; the gas detection module comprises a bulk acoustic wave resonator and a metasurface structure arranged on the bulk acoustic wave resonator; the light source emits light waves towards the metasurface structure, and the metasurface structure is configured to absorb the light waves at the characteristic absorption spectrum wavelength of the target gas in the gas chamber, convert the light into heat energy and cause frequency drift of the bulk acoustic wave resonator so as to be used for detecting the type and concentration of the gas. The gas detection device can be applied in various environments, and has the advantages of high frequency, high sensitivity, wireless and passive properties, light weight and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of detection, and relates to a detection device containing a metasurface structure and a bulk acoustic resonator, in particular to a gas detection device and a gas type and concentration detection method. BACKGROUND

[0002] In the field of gas detection, the simultaneous detection of the type and concentration of multi-component gas is a difficulty that needs to be broken through in the industry.

[0003] CN119246469A discloses a gas concentration sensing system and a gas concentration detection method. The system is based on multiple "graphene tilted fiber grating", uses the optical properties of graphene to enhance the response signals of different gases, and matches a wide spectrum light source, a spectrum analyzer and a demodulation system to perform spectrum analysis on the light transmitted by each of the multiple graphene tilted fiber gratings, to obtain the corresponding spectrum analysis results of each of the multiple graphene tilted fiber gratings, and based on the spectrum analysis results, to calculate the gas concentrations of multiple preset gases. Although this design has made progress in integration, the grating manufacturing process is complex, and a high-precision spectrum analyzer is required, which is difficult to popularize on a large scale.

[0004] CN114486128A discloses a gas leakage detection device and method combining ultrasonic waves and passive infrared imaging. The detection device has an optical detection assembly, an ultrasonic detection assembly, a central control module and a data comparison module installed in the shell. The optical detection assembly includes an infrared detector and a visible light imaging CCD. The infrared detector cooperates with the ultrasonic detection assembly to detect the leakage point and obtain the imaging signal of the point. The central control module analyzes the point image and calculates and estimates the pressure values inside and outside the leakage point to solve the defects of the current passive gas infrared imaging method for detecting gas leakage, such as limited detection of gas types and inability to detect the flow rate of the leaked gas. This scheme needs to detect, convert and process imaging information, and the calculation and conversion involved are complex, which can easily affect accuracy.

[0005] At present, the existing technical solutions have the problems of insufficient system complexity and integration. When high-precision optical detection devices are used, they rely on precise optical elements and complex structures, or need to rely on multiple equipment combinations, resulting in a large volume, a complicated operation process, deployment difficulties, high maintenance costs and poor scalability. Therefore, it is necessary to develop new gas concentration detection devices and methods to break through the technical bottlenecks of system complexity, environmental adaptability and scalability under the premise of simultaneous detection of multiple gases, to meet the stringent requirements of real-time, portability and reliability in industrial safety, environmental monitoring and other scenarios. SUMMARY

[0006] In view of the problems in the prior art, the purpose of the present application is to provide a gas detection device and a gas type and concentration detection method, the gas detection device comprising a gas detection module, a light source and a gas chamber; the gas detection module comprising a bulk acoustic resonator and a metasurface structure disposed thereon; the light source emits light waves toward the metasurface structure, the metasurface structure is configured to absorb light waves at a characteristic absorption spectrum wavelength of a target gas in the gas chamber, convert light into heat energy, cause frequency drift of the bulk acoustic resonator, and thereby detect the type and concentration of the gas. The gas detection device can be applied in various environments and has the advantages of high frequency and high sensitivity, wireless and passive, light weight, etc.

[0007] To achieve this purpose, the present application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a gas detection device, comprising:

[0009] a gas detection module comprising a bulk acoustic resonator and a metasurface structure disposed on the surface of the bulk acoustic resonator, the metasurface structure being configured to absorb light waves at a characteristic absorption spectrum wavelength of a target gas;

[0010] a light source disposed opposite the gas detection module and having an emission direction toward the metasurface structure, for emitting light waves containing the characteristic absorption spectrum wavelength of the target gas;

[0011] a gas chamber disposed between the light source and the gas detection module and in communication with the environment to be detected.

[0012] The gas detection device provided by the application comprises a gas detection module, a body acoustic wave resonator, a light source and a light detector.

[0013] The following is a preferred technical solution of the application, but is not a limitation of the technical solution provided by the application. The technical purpose and beneficial effects of the application can be better achieved and implemented through the following technical solution.

[0014] As a preferred technical solution of the application, the gas detection device comprises at least two gas detection modules, and the super surface structure of each gas detection module is matched with different target gases.

[0015] As a preferred technical solution of the application, the body acoustic wave resonator comprises a high harmonic body acoustic wave resonator.

[0016] Preferably, the high harmonic body acoustic wave resonator comprises a substrate, a bottom electrode, a piezoelectric layer and a top electrode which are arranged in layers.

[0017] Preferably, the high harmonic body acoustic wave resonator further comprises a seed layer which is arranged between the substrate and the piezoelectric layer and has a part in contact with the piezoelectric layer.

[0018] Preferably, the super surface structure comprises a dielectric passivation layer and a sub-wavelength structure layer which are arranged in layers.

[0019] In the present application, the top electrode of the bulk acoustic resonator is used to realize the combination and connection of the metasurface structure.

[0020] Preferably, the periodically arranged sub-wavelength structures in the sub-wavelength structure layer are matched with the characteristic absorption spectrum wavelength of the target gas in the mid-infrared waveband.

[0021] Preferably, the gas detection module further comprises a potential connection line; the potential connection line is arranged between the bulk acoustic resonator and the metasurface structure and forms an electrical connection with the bulk acoustic resonator.

[0022] Preferably, the potential connection line is arranged between the top electrode and the dielectric passivation layer and forms an electrical connection with the top electrode.

[0023] Preferably, the gas detection device further comprises an antenna connected to the potential connection line for transmitting the frequency signal of the bulk acoustic resonator.

[0024] Preferably, the gas detection device further comprises a data processing module in wireless signal connection with the antenna for receiving and processing the frequency signal of the bulk acoustic resonator in the gas detection module, calculating the frequency value and the frequency drift value.

[0025] Preferably, the gas detection device further comprises a data storage module in electrical connection with the data processing module for storing the frequency drift value, forming data and establishing a database.

[0026] Preferably, the gas detection device further comprises a data comparison module in electrical connection with the data processing module and the data storage module for comparing the test information with the data in the database and outputting the test result.

[0027] Preferably, the gas detection device further comprises a housing support structure; the housing support structure comprises a head portion, a middle portion and a tail portion; the head portion has a head portion accommodating space for accommodating the light source, the tail portion has a tail portion accommodating space for accommodating the gas detection module; the middle portion is hollowed out to form the gas chamber.

[0028] Preferably, the gas detection device further comprises a battery arranged in the head portion accommodating space for supplying power to the light source.

[0029] Preferably, the head portion has an outer surface profile facing the environment to be searched, which is a circular arc line or a streamline type, for buffering the fluid impact in the environment to be searched.

[0030] In a second aspect, the present invention provides a method for detecting gas types and concentrations, the method using the gas detection device described in the first aspect, the method comprising:

[0031] According to the number of gas detection modules in the gas detection device being n, the gas detection modules and the corresponding target gases are numbered from 1 to n, where n≥1;

[0032] The gas detection device is placed in a simulated environment, the light source is turned on, and a simulated detection is performed. The initial atmosphere in the simulated environment does not contain the target gas. Then each target gas is introduced into the simulated environment separately, and the concentration of the target gas is used as the horizontal axis x. n , obtain the frequency drift value of the bulk acoustic wave resonator in each gas detection module as the vertical coordinate y n , with data [x n ,y1,y2,…,y n ]Build a database;

[0033] Place the gas detection device in the environment to be detected, turn on the light source, and perform a working test; record the frequency drift value Y of the bulk acoustic wave resonator in each gas detection module at the test time point t. n , forming the test information [t,Y1,Y2,…,Y n ]; the test information [t,Y1,Y2,…,Y n ] into the database, so that Y n with y n Corresponding, matching the corresponding data [x n ,y1,y2,…,y n ], output the concentration x of the target gas numbered n at time t n .

[0034] As a preferred technical solution of the present invention, the detection method further comprises the following steps: n ,y1,y2,…,y n ] is processed into a statistical graph with shape features and / or position features, and a visual database is established with the statistical graph; the test information [t, Y1, Y2, …, Y n ] is processed into a corresponding statistical graph, substituted into the visualization database, and matched with the corresponding data [x n ,y1,y2,…,y n ] to form a statistical chart, outputting the concentration x of the target gas numbered n at time t n .

[0035] As a preferred technical solution of the present invention, the statistical graph includes at least one of a scatter plot, a line graph, a column graph, a bar graph, a pie chart or an area graph.

[0036] Preferably, the statistical graph is a bar graph, and the data [x n ,y1,y2,…,y n ]Form each x n Corresponding barcode, test information [t,Y1,Y2,…,Y n ] forms the barcode corresponding to each moment t.

[0037] In a third aspect, the present invention provides a use of the gas detection device described in the first aspect, wherein the use includes detecting leakage of natural gas, coal gas or industrial harmful gas.

[0038] Compared with the existing technical solutions, the present invention has at least the following beneficial effects:

[0039] The metasurface structure in the gas detection device described in the present invention replaces the filter on the gas sensor in traditional gas detection devices. While smaller in size, it still performs a filtering function. Metasurface structures of specific sizes and materials have a higher absorption rate in specific wavelength bands, allowing the metasurface structure to correspond to specific target gases and, therefore, detect the type of gas. The combination of the metasurface structure and the bulk acoustic wave resonator changes the frequency drift of the bulk acoustic wave resonator. This frequency drift is then correlated with the type and concentration of the gas, enabling real-time analysis, dynamic monitoring of gas concentration, and quantitative calculation of gas concentration, enabling high-precision detection. The detection method is simple and accurate.

[0040] The bulk acoustic wave resonator in this invention generates electrical signals autonomously based on the piezoelectric effect, eliminating the need for an external power supply and overcoming the power-dependence limitations of conventional detection equipment. The gas detection device described in this invention is a micro-integrated device with high integration and adaptability. It can be used for detecting working gases in industry and for measuring the type and concentration of natural gas, coal gas, or other hazardous gases in various environments, including homes. It is easy to install and has wide practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of the structure of a gas detection device in one embodiment.

[0042] Figure 2 The figure is a schematic diagram of the cross-sectional structure of a gas detection module in one embodiment.

[0043] Figure 3 yes Figure 1 Enlarged view of the dotted box in the middle circle.

[0044] Figures 4a to 4f yes Figure 2 Schematic diagram of the gas detection module in the production process.

[0045] Figures 1 to 4f In particular, 10 - gas detection module, 20 - bulk acoustic resonator, 30 - metasurface structure, 40 - potential connection line, 21 - substrate, 22 - bottom electrode, 23 - piezoelectric layer, 24 - top electrode, 25 - seed layer, 31 - dielectric passivation layer, 32 - subwavelength structure layer, 33 - periodically arranged subwavelength structures, 50 - light source, 60 - gas chamber, 70 - shell support structure, 71 - head, 72 - middle, 73 - tail.

[0046] Figure 5 is a mechanism diagram of frequency drift of bulk acoustic resonator.

[0047] Figure 6 is an impedance-frequency curve diagram of bulk acoustic resonator, showing a frequency drift.

[0048] Figure 7 is the bar code result obtained when working detection is performed at five test time points t in application example 1. DETAILED DESCRIPTION

[0049] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present application and should not be regarded as specific limitations on the present application.

[0050] Bulk acoustic resonator is a device that utilizes the physical properties of materials to achieve acoustic resonance within a specific frequency range. Bulk acoustic wave (BAW) resonator is a type of acoustic resonator, unlike surface acoustic wave device (SAW), bulk acoustic resonator utilizes the characteristics of acoustic wave propagation throughout the material volume, this design enables them to work at higher frequencies, and usually has better temperature stability and higher quality factor (Q value). Bulk acoustic resonator belongs to the device elements based on piezoelectric effect, piezoelectric effect refers to the fact that some materials can generate electric charge when subjected to force, or mechanical deformation occurs when an electric field is applied, this effect makes bulk acoustic resonator have inherent resonant frequency, which is affected by the characteristics of piezoelectric material, resonator structure and external environment, etc.

[0051] Metasurface (structure) is usually a multilayer structure formed by a bottom metal film, an intermediate dielectric film and a top subwavelength structure, subwavelength structure is a synthetic periodic array, which can interact with incident light to produce resonance, and will convert absorbed light into heat energy near the resonant wavelength. The incident light can be visible light, near-infrared, terahertz or microwave light waves, but the metasurface structure usually only absorbs electromagnetic energy of a certain wave band due to the design of size and material.

[0052] Based on the above, in some specific embodiments, the present application provides a gas detection device, such as Figure 1 As shown in the drawings, the gas detection device comprises:

[0053] a gas detection module 10, comprising a bulk acoustic resonator 20, and a metasurface structure 30 disposed on the surface of the bulk acoustic resonator 20, the metasurface structure 30 being used for absorbing light waves at characteristic absorption spectrum wavelengths of a target gas;

[0054] a light source 50, disposed opposite to the gas detection module 10, and the light emission direction is towards the metasurface structure 30, for emitting light waves containing characteristic absorption spectrum wavelengths of the target gas;

[0055] a gas chamber 60, disposed between the light source 50 and the gas detection module 10, and in communication with the environment to be detected.

[0056] Different gases all have their unique atomic composition and molecular structure, due to the difference in internal structure and energy state, which determines that they can absorb electromagnetic radiation of specific frequency (or wavelength), i.e. have different characteristic absorption spectrum wavelengths. But usually the absorption rate of the gas for light waves at its characteristic absorption spectrum wavelengths cannot reach 100%, i.e. at the characteristic absorption spectrum wavelengths only a part of the light waves is absorbed, and there will be remaining light waves. Based on this principle, the gas detection device described in the present application is designed to comprise a gas detection module 10, a light source 50 and a gas chamber 60, the gas chamber 60 is disposed between the light source 50 and the gas detection module 10 and is in communication with the environment to be detected, the light waves emitted by the light source 50 will pass through the gas chamber 60 and irradiate onto the gas detection module 10. When the gas in the environment to be detected enters the gas chamber 60, due to the presence of the target gas, it will absorb some light waves of specific wavelengths (i.e. light waves at the characteristic absorption spectrum wavelengths), the remaining light wave energy changes, resulting in changes in the light waves and light wave energy irradiating onto the gas detection module 10, and the specific gas detection module 10 proposed in the present application can realize detection of the changed light waves.

[0057] Specifically, the gas detection module 10 of the present invention is a bulk acoustic wave resonator 20 designed based on a metasurface structure 30. The metasurface structure 30 (including the structure, dimensions, and materials that affect the resonant wavelength) is designed and configured to match the corresponding target gas. That is, the wavelength band absorbed by the metasurface structure 30 is adjusted to the characteristic absorption spectrum wavelength of the target gas, so that the metasurface structure 30 only absorbs light waves at this wavelength. Then, when the environment to be detected does not contain the target gas, the complete light wave at this wavelength can be irradiated onto the metasurface structure 30, and the light is converted into heat energy through the metasurface structure 30. The heat energy affects the temperature of the BAW resonator 20 connected thereto through direct heat conduction and / or auxiliary heating through Joule heat or dielectric loss of the metal structure. In the environment to be detected that does not contain the target gas, the temperature of the BAW resonator 20 is stable and has a natural frequency; when the environment to be detected contains the target gas and enters the gas chamber 60, its absorption causes the light wave at this wavelength irradiated onto the metasurface structure 30 to change, which in turn causes the converted heat energy to change, resulting in a change in the temperature of the BAW resonator 20. The Young's modulus and density of the BAW resonator 20 will change with the change in temperature, thereby causing the natural frequency of the resonator to shift, that is, the resonator undergoes frequency drift, which is referred to as frequency drift. The mechanism of frequency drift is as follows Figure 5 As shown, Figure 6 The impedance-frequency curve shows a frequency drift result; further, the degree of frequency drift is linearly related to the change in temperature. Therefore, it is possible to eventually establish a mapping relationship between the concentration change of the target gas and the degree of frequency drift of the resonator, and detect the concentration based on the degree of frequency drift.

[0058] In one embodiment, the gas detection device includes at least two gas detection modules 10 , and the metasurface structure 30 of each gas detection module 10 matches a different target gas.

[0059] It is further understood that when the gas detection device includes multiple gas detection modules 10, it is possible to determine whether the environment to be detected contains the corresponding target gas based on whether the corresponding gas detection module 10 has frequency drift, thereby achieving gas type detection.

[0060] In one embodiment, the BAW resonator 20 comprises a high harmonic BAW resonator (HBAR).

[0061] High-order bulk acoustic wave resonators 20 specifically refer to resonators designed to exploit higher-order modes of acoustic wave propagation in a medium, beyond the most basic propagation mode. By controlling these higher-order modes, high-order bulk acoustic wave resonators 20 are well-suited for electronic devices that require lightweight and sophisticated design. Compared to conventional thin film bulk acoustic wave resonators (FBARs), the high-frequency operating range of high-order bulk acoustic wave resonators is more sensitive to small temperature changes, and the higher Q value can improve the detection limit of the gas detection device of the present invention.

[0062] In one embodiment, Figure 2 As shown, the high-harmonic bulk acoustic wave resonator includes a substrate 21, a bottom electrode 22, a piezoelectric layer 23 and a top electrode 24 that are stacked.

[0063] In one embodiment, the substrate includes silicon; the piezoelectric layer 23 includes at least one of aluminum nitride (AlN), scandium-doped aluminum nitride (ScAlN), lead zirconate titanate (PZT), lithium niobate (LiNbO3) or lithium tantalate (LiTaO3); the bottom electrode 22 and the top electrode 24 include at least one of molybdenum (Mo), tungsten (W) or platinum (Pt).

[0064] In one embodiment, Figure 2 As shown, the high-harmonic bulk acoustic wave resonator further includes a seed layer 25 . The seed layer 25 is disposed between the substrate 21 and the piezoelectric layer 23 and has a portion in contact with the piezoelectric layer 23 .

[0065] In one embodiment, the seed layer 25 includes aluminum nitride (AlN).

[0066] In one embodiment, Figure 2 as well as Figure 3 As shown, the metasurface structure 30 includes a dielectric passivation layer 31 and a sub-wavelength structure layer 32 that are stacked.

[0067] In one embodiment, the dielectric passivation layer 31 includes silicon dioxide (SiO 2 ).

[0068] It should be noted that the dielectric passivation layer 31 described in the present invention primarily functions as a dielectric layer for the metasurface structure 30, forming part of the metasurface and assisting in temperature increase through dielectric loss. Furthermore, because it is disposed on the upper surface of the BAW resonator 20, particularly covering the top electrode, it also functions as a passivation layer for the BAW resonator 20, effectively protecting the electrode from oxidation. The dielectric and passivation layers are combined into a single, shared layer, enhancing integration.

[0069] In one embodiment, the periodically arranged subwavelength structures 33 in the subwavelength structure layer 32 match the characteristic absorption spectrum wavelength of the target gas in the mid-infrared band.

[0070] In one embodiment, the gas detection module 10 further includes a potential connection line 40 ; the potential connection line 40 is disposed between the BAW resonator 20 and the metasurface structure 30 , and is electrically connected to the BAW resonator 20 .

[0071] In one embodiment, the potential connection line 40 is disposed between the top electrode 24 and the dielectric passivation layer 31 and is electrically connected to the top electrode 24 .

[0072] In one embodiment, the gas detection device further includes an antenna, which is connected to the potential connection line 40 and is used to transmit the frequency signal of the bulk acoustic wave resonator 20 .

[0073] In one embodiment, the gas detection device further includes a data processing module; the data processing module forms a wireless signal connection with the antenna, and is used to receive and process the frequency signal of the bulk acoustic wave resonator 20 in the gas detection module 10, and calculate the frequency value and the frequency drift value.

[0074] In one embodiment, the data processing module is a network analyzer.

[0075] In one embodiment, the gas detection device further includes a data storage module, which is electrically connected to the data processing module and is used to store frequency drift values, form data, and establish a database.

[0076] In one embodiment, the gas detection device further includes a data comparison module, which is electrically connected to the data processing module and the data storage module, and is used to compare the test information with the data in the database and output the test results.

[0077] In one embodiment, the data processing module, data storage module and data comparison module are integrated into a host.

[0078] In one embodiment, Figure 1 As shown, the gas detection device also includes a shell support structure 70; the shell support structure 70 includes a head 71, a middle part 72 and a tail 73; the head 71 has a head accommodating space for accommodating the light source 50, and the tail 73 has a tail accommodating space for accommodating the gas detection module 10; the middle part 72 is hollowed out to form the gas chamber 60.

[0079] In one embodiment, the material of the air chamber 60 or the housing support structure 70 includes alumina.

[0080] The housing support structure 70 of the present invention is preferably made of alumina, which has excellent mechanical strength and high thermal stability, and a good match with the thermal expansion coefficient of the MEMS chip. Metallization traces can be integrated using thick-film or thin-film processes, making it suitable for high reliability and harsh environments.

[0081] In one embodiment, the gas detection device further includes a battery, which is disposed in the head accommodating space and is used to power the light source 50 .

[0082] In one embodiment, the outer surface contour of the head 71 facing the environment to be searched is an arc or streamlined shape, so as to cushion the impact of fluid in the environment to be searched.

[0083] In some specific embodiments, the present invention provides a method for manufacturing the gas detection device described in the above embodiment, the manufacturing method comprising:

[0084] First, a bulk acoustic wave resonator 20 is manufactured, and then a metasurface structure 30 is manufactured to obtain a gas detection module 10; at least one gas detection module 10 is assembled and connected with a light source 50 and a gas chamber 60 to obtain a gas detection device.

[0085] In one embodiment, after the BAW resonator is manufactured, potential connection lines are manufactured on the electrode interface of the BAW resonator, and then the metasurface structure is manufactured.

[0086] In one embodiment, Figures 4a to 4f as well as Figure 2 As shown, the manufacturing method includes the following steps:

[0087] S1. Providing a substrate 21, preparing a seed layer 25 on the surface of the substrate 21; preparing a bottom electrode 22 on the seed layer 25;

[0088] S2. Patterning the bottom electrode 22 to expose the seed layer 25; preparing a piezoelectric layer 23 on the exposed seed layer 25 and covering the bottom electrode 22;

[0089] S3. The piezoelectric layer 23 is patterned to expose the bottom electrode 22; a top electrode 24 is prepared on the piezoelectric layer 23 and the exposed bottom electrode 22 to obtain a high-harmonic bulk acoustic wave resonator portion;

[0090] S4. Patterning the top electrode 24 to expose the piezoelectric layer 23 and forming electrode interfaces exposing the bottom electrode 22 and the top electrode 24; preparing a potential connection line 40 in the electrode interface to obtain a multilayer thin film stack;

[0091] S5. Preparing a dielectric passivation layer 31 on the upper surface of the multilayer thin film stack, the dielectric passivation layer 31 covering the top electrode 24, the potential connection line 40 and the exposed piezoelectric layer 23; then patterning the dielectric passivation layer 31;

[0092] S6. A periodically arranged subwavelength structure 33 is prepared on the dielectric passivation layer 31 to form a patterned subwavelength structure layer 32, constituting part of the metasurface structure 30, to obtain a gas detection module 10;

[0093] S7. Assemble and connect at least one of the gas detection modules 10 with the light source 50 and the gas chamber 60 to obtain a gas detection device.

[0094] In one embodiment, the bulk acoustic wave resonator 20, the potential connection line 40 and the metasurface structure 30 are manufactured by microelectronics processing; the connection between the light source 50, the gas chamber 60 and the gas detection module 10 is processed by welding technology.

[0095] The bulk acoustic wave resonator 20 and the metasurface structure 30 in the present invention preferably use microelectronics technology to process each layer of the structure, combined with sputtering and deposition processes to connect different parts. This process flow improves the manufacturing accuracy and reliability of the device.

[0096] In one embodiment, the process of preparing the potential connection line 40 in step S4 includes an unraveling-stripping process.

[0097] In one embodiment, when preparing the dielectric passivation layer 31 in step S5, the potential connection line 40 deposited at the electrode interface is exposed to facilitate subsequent connection with the antenna to transmit the frequency drift signal to a data processing module, such as a network analyzer.

[0098] In one embodiment, the patterned sub-wavelength structure layer 32 is prepared in step S7 by using an unwinding-stripping process.

[0099] It should be noted that the lift-off process is a mature and commonly used metal patterning method in the existing technology. When the preparation process of the subwavelength structure adopts photolithography and lift-off process, the material selection, size, and structural design need to correspond to the target gas to be detected.

[0100] In some specific embodiments, the present invention provides a method for detecting gas types and concentrations, wherein the method uses the gas detection device described in the above embodiment, and the method includes:

[0101] According to the number n of gas detection modules 10 in the gas detection device, the gas detection modules 10 and the corresponding target gases are numbered from 1 to n, where n≥1;

[0102] The gas detection device is placed in a simulated environment, the light source 50 is turned on, and a simulated detection is performed. The initial atmosphere in the simulated environment does not contain the target gas. Then each target gas is introduced into the simulated environment separately, and the concentration of the target gas is used as the horizontal axis x. n , obtain the frequency drift value of the bulk acoustic wave resonator 20 in each of the gas detection modules 10 as the vertical coordinate y n , with data [x n ,y1,y2,…,y n ]Build a database;

[0103] The gas detection device is placed in the environment to be detected, the light source 50 is turned on, and a working test is performed; the frequency drift value Y of the bulk acoustic wave resonator 20 in each gas detection module 10 at the test time point t is recorded. n , forming the test information [t,Y1,Y2,…,Y n ]; the test information [t,Y1,Y2,…,Y n ] into the database, so that Y n with y n Corresponding, matching the corresponding data [x n ,y1,y2,…,y n ], output the concentration x of the target gas numbered n at time t n .

[0104] It can be understood that the BAW resonator 20 has its own natural frequency when it is not affected by external factors. Due to the illumination by the light source 50, its temperature increases, and a frequency drift occurs relative to the natural frequency. In the initial atmosphere, there is no target gas in the gas chamber 60 and the composition is stable, so that the BAW resonator 20 at this time has a stable frequency drift degree.

[0105] In one embodiment, the detection method further comprises converting the data [x n ,y1,y2,…,y n ] is processed into a statistical graph with shape features and / or position features, and a visual database is established with the statistical graph; the test information [t, Y1, Y2, …, Y n] is processed into a corresponding statistical graph, substituted into the visualization database, and matched with the corresponding data [x n ,y1,y2,…,y n ] to form a statistical chart, outputting the concentration x of the target gas numbered n at time t n .

[0106] In one embodiment, the statistical graph includes at least one of a scatter plot, a line graph, a column graph, a bar graph, a pie chart, or an area graph.

[0107] In one embodiment, the statistical graph is a bar graph, and the data [x n ,y1,y2,…,y n ]Form each x n Corresponding barcode, test information [t,Y1,Y2,…,Y n ] forms the barcode corresponding to each moment t.

[0108] It can be understood that in the database according to the test information [t, Y1, Y2, ..., Y n ]Retrieve matching data[x n ,y1,y2,…,y n ], can be automatically operated through the data processing module, data storage module and data comparison module. Of course, since the data is visualized, it can also be manually compared and selected based on the shape characteristics of the barcode.

[0109] In some specific embodiments, the present invention provides a use of the gas detection device described in the above embodiment, which includes detecting leakage of natural gas, coal gas or industrial hazardous gas.

[0110] Example 1

[0111] This embodiment provides a gas detection device, such as Figures 1 to 3 As shown, the gas detection device includes:

[0112] Four different gas detection modules 10, each comprising a bulk acoustic wave resonator 20 and a metasurface structure 30 disposed on a surface of the bulk acoustic wave resonator 20, the metasurface structure 30 being connected to the bulk acoustic wave resonator 20 via a potential connection line 40; the metasurface structure 30 being configured to absorb light waves at a characteristic absorption spectrum wavelength of the target gas;

[0113] The BAW resonator 20 is a high-harmonic BAW resonator; the high-harmonic BAW resonator includes a stacked substrate 21, a bottom electrode 22, a piezoelectric layer 23, and a top electrode 24; the high-harmonic BAW resonator also includes a seed layer 25, which is arranged between the substrate 21 and the piezoelectric layer 23 and has a portion in contact with the piezoelectric layer 23; the metasurface structure 30 includes a stacked dielectric passivation layer 31 and a subwavelength structure layer 32; the potential connection line 40 is arranged between the top electrode 24 and the dielectric passivation layer 31, and forms an electrical connection between the top electrode 24 and the dielectric passivation layer 31;

[0114] The periodically arranged subwavelength structures 33 in the subwavelength structure layer 32 match the wavelength of the characteristic absorption spectrum of the target gas in the mid-infrared band; the metasurface structures 30 of the four gas detection modules 10 are different, that is, the subwavelength structure layers 32 are different (referring to the size, shape structure and material of the subwavelength structure), so as to respectively match the four target gases carbon monoxide, sulfur dioxide, methane and acetylene; the metasurface structure 30 with carbon monoxide absorbs light waves at 4.60 μm of the characteristic absorption spectrum of carbon monoxide, the metasurface structure 30 with sulfur dioxide absorbs light waves at 7.26 μm of the characteristic absorption spectrum of sulfur dioxide, the metasurface structure 30 with methane absorbs light waves at 3.27 μm of the characteristic absorption spectrum of methane, and the metasurface structure 30 with acetylene absorbs light waves at 3.03 μm of the characteristic absorption spectrum of acetylene;

[0115] The gas detection device further includes a light source 50, which is arranged opposite to the gas detection module 10 and emits light in a direction toward the metasurface structure 30, and is used to emit light waves at a wavelength containing a characteristic absorption spectrum of the target gas;

[0116] The gas detection device further includes a gas chamber 60, which is disposed between the light source 50 and the gas detection module 10 and is in communication with the environment to be detected;

[0117] The gas detection device further includes a housing support structure 70; the housing support structure 70 includes a head 71, a middle portion 72 and a tail portion 73; the head 71 has a head accommodating space for accommodating the light source 50 ( Figure 1 The dotted-line box in the middle quadrilateral represents that the light source 50 is disposed inside. The tail portion 73 has a tail accommodation space for accommodating the gas detection module 10. The middle portion 72 is hollowed out to form the gas chamber 60. The outer surface contour of the head portion 71 facing the environment to be searched is an arc line, which is used to buffer the impact of the fluid in the environment to be searched.

[0118] The gas detection device further includes a battery, which is disposed in the head receiving space and is used to power the light source 50;

[0119] The gas detection device further includes an antenna and a data processing module; the antenna is electrically connected to the potential connection line 40, and the antenna is used to establish a wireless signal connection between the gas detection module 10 and the data processing module; the data processing module is used to receive and process the frequency signal of the bulk acoustic wave resonator 20 in the gas detection module 10, and calculate the frequency value and the frequency drift value;

[0120] The gas detection device further includes a data storage module, which is electrically connected to the data processing module and is used to store frequency drift values, form data, and establish a database;

[0121] The gas detection device further includes a data comparison module, which is electrically connected to the data processing module and the data storage module, and is used to compare test information with data in a database and output test results.

[0122] This embodiment also provides a method for manufacturing the gas detection device, such as Figures 4a to 4f and Figure 2 As shown, the manufacturing method includes:

[0123] S1. A silicon substrate 21 is formed by sputtering an aluminum nitride layer on the surface of the substrate 21 as a seed layer 25; a molybdenum layer is deposited on the seed layer 25 as a bottom electrode 22;

[0124] S2. Patterning the bottom electrode 22 to expose the seed layer 25; preparing a piezoelectric layer 23 on the exposed seed layer 25 and covering the bottom electrode 22;

[0125] S3. The piezoelectric layer 23 is patterned to form a through hole, wherein the bottom electrode 22 is exposed in the through hole; molybdenum is deposited on the piezoelectric layer 23 and the exposed bottom electrode 22, and covers the inner wall of the through hole to form a top electrode 24, thereby obtaining a high-harmonic bulk acoustic wave resonator portion;

[0126] S4. Patterning the top electrode 24 to expose the piezoelectric layer 23 and forming electrode interfaces that expose the bottom electrode 22 and the top electrode 24, respectively; depositing potential connection lines 40 in the electrode interfaces using an unwinding-stripping process to obtain a multilayer thin film stack;

[0127] S5. Depositing a silicon dioxide layer on the upper surface of the multilayer thin film stack as a dielectric passivation layer 31, the dielectric passivation layer 31 covering the top electrode 24, the potential connection line 40, and the exposed piezoelectric layer 23; then patterning the dielectric passivation layer 31 and exposing the potential connection line 40 for subsequent connection to the antenna;

[0128] S6. A periodically arranged sub-wavelength structure 33 is deposited on the dielectric passivation layer 31 by a lift-off process to form a patterned sub-wavelength structure layer 32, constituting part of the metasurface structure 30, to obtain a gas detection module 10;

[0129] S7. Assemble and connect four different gas detection modules 10, batteries, light sources 50 and the outer shell support structure 70; wherein, the batteries and light sources 50 are accommodated in the space of the head 71 and fixedly connected to the outer shell support structure 70; the gas detection module 10 is accommodated in the space of the tail 73 and fixedly connected to the outer shell support structure 70; the middle part 72 of the outer shell support structure 70 forms an air chamber 60 to obtain a gas detection device.

[0130] Application Example 1

[0131] This application example provides a method for detecting gas types and concentrations, which is used to detect the types (presence) and concentration levels of four target gases: carbon monoxide, sulfur dioxide, methane, and acetylene. The detection method uses the gas detection device provided in Example 1 and performs the following steps:

[0132] T1. Given that there are four gas detection modules 10 in the gas detection device, the gas detection modules 10 and their corresponding target gases are numbered from 1 to 4. Specifically, the gas detection module 10 corresponding to carbon monoxide and its corresponding target gases is numbered 1; the gas detection module 10 corresponding to sulfur dioxide and its corresponding target gases is numbered 2; the gas detection module 10 corresponding to methane and its corresponding target gases is numbered 3; and the gas detection module 10 corresponding to acetylene and its corresponding target gases is numbered 4.

[0133] T2. The gas detection device is placed in a simulated environment, where the initial atmosphere of the simulated environment is air, equivalent to a concentration of each target gas of 0. The light source 50 is turned on for simulated detection. The light source 50 emits a parallel light beam. After the light beam enters the gas chamber 60, the initial atmosphere in the gas chamber 60 absorbs part of the light of a specific wavelength. The remaining light waves are irradiated onto the metasurface structure 30 of the gas detection module 10, causing the temperature of the BAW resonator 20 to rise and the frequency drift to occur. Since the four target gases are not present in the initial atmosphere, the light waves at 4.60 μm, 7.26 μm, 3.27 μm, and 3.03 μm are not additionally absorbed. At this time, the corresponding gas detection module 10 absorbs the most converted heat energy, resulting in the maximum frequency drift of the BAW resonator 20.

[0134] The concentration of the target gas is the horizontal axis x n , obtain the frequency drift value of the bulk acoustic wave resonator 20 in each of the gas detection modules 10 as the vertical coordinate y n , with data [xn ,y1,y2,y3,y n ] Establish a database; specifically, taking carbon monoxide as an example, the concentration in the initial atmosphere is 0, the horizontal coordinate of the test result is x1=0, and the data [0, y1, y2, y3, y4] is recorded. Then, carbon monoxide is introduced into the simulated environment alone, and the concentration x1 is gradually increased. At each concentration test point, the data [x1, y1, y2, y3, y4] is recorded to establish a database; the data [x1, y1, y2, y3, y4] is processed into a bar graph to form a bar code corresponding to each concentration test point, and a visual database is established with the bar code of the bar graph;

[0135] Similarly, after the simulation detection of carbon monoxide is completed, sulfur dioxide, methane, and acetylene are introduced separately for simulation detection, and the data [x2, y1, y2, y3, y4], data [x3, y1, y2, y3, y4], and data [x4, y1, y2, y3, y4] are all established as databases and visualization databases;

[0136] T3. Place the gas detection device in the environment to be detected, turn on the light source 50, and perform a working test; record the frequency drift value Y of each of the bulk acoustic wave resonators 20 in the gas detection module 10 at the test time point t. n , forming the test information [t, Y1, Y2, Y3, Y4]; processing the test information [t, Y1, Y2, Y3, Y4] into the corresponding bar graph to form a barcode; such as Figure 7 As shown, the barcodes at five times t1 to t5 are recorded and substituted into the visualization database to match the corresponding data [x n ,y1,y2,y3,y4], and outputs the target gas numbered n and its concentration x at time t1 to t5 respectively. n .

[0137] Specifically, Figure 7 There are five small barcodes in total, and each small block has four sets of data. The four sets of data are numbered 1 to 4, which are the frequency drift degrees of four bulk acoustic wave resonators with different metasurface structures. One set of data can be used to obtain the concentration of a gas, and four sets of data can be used to obtain the four gas contents of the mixed gas in the gas chamber at this time. According to the difference in the contents of these four gases, it can be distinguished whether the mixed gas is coal gas or other gases, etc. By comparing with the data of real coal gas and other gases, the small block can be defined as coal gas. The next time this barcode appears, the result of coal gas can be directly obtained.

[0138] In summary, the present invention provides a gas type and gas concentration detection device with the advantages of high frequency, high sensitivity, wireless passivity, and light weight. The device can be used to detect gas types and concentrations in various environments such as mines and sewers, and serve as an early warning for workers who need to come into contact with harmful gases.

[0139] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0140] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0141] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A gas detection device, characterized in that: include: A gas detection module includes a bulk acoustic wave resonator and a metasurface structure provided on a surface of the bulk acoustic wave resonator, wherein the metasurface structure is configured to absorb light waves at a characteristic absorption spectrum wavelength of a target gas; a light source, disposed opposite to the gas detection module and oriented toward the metasurface structure, for emitting light waves at wavelengths containing characteristic absorption spectra of the target gas; The gas chamber is arranged between the light source and the gas detection module and is communicated with the environment to be detected.

2. The gas detection device according to claim 1, characterized in that The gas detection device comprises at least two gas detection modules, and the metasurface structure of each gas detection module matches a different target gas.

3. The gas detection device according to claim 1 or 2, characterized in that: The bulk acoustic wave resonator includes a high-harmonic bulk acoustic wave resonator; Preferably, the high-harmonic bulk acoustic wave resonator comprises a substrate, a bottom electrode, a piezoelectric layer and a top electrode that are stacked; Preferably, the high-harmonic bulk acoustic wave resonator further comprises a seed layer, wherein the seed layer is disposed between the substrate and the piezoelectric layer and has a portion in contact with the piezoelectric layer; Preferably, the metasurface structure comprises a dielectric passivation layer and a sub-wavelength structure layer stacked together; Preferably, the periodically arranged subwavelength structures in the subwavelength structure layer match the characteristic absorption spectrum wavelength of the target gas in the mid-infrared band; Preferably, the gas detection module further includes a potential connection line; the potential connection line is arranged between the bulk acoustic wave resonator and the metasurface structure, and forms an electrical connection with the bulk acoustic wave resonator.

4. The gas detection device according to claim 3, characterized in that: The potential connection line is arranged between the top electrode and the dielectric passivation layer and is electrically connected to the top electrode; Preferably, the gas detection device further comprises an antenna, which is connected to the potential connection line and is used to transmit the frequency signal of the bulk acoustic wave resonator.

5. The gas detection device according to claim 4, characterized in that: The gas detection device further includes a data processing module, which forms a wireless signal connection with the antenna and is used to receive and process the frequency signal of the bulk acoustic wave resonator in the gas detection module and calculate the frequency value and the frequency drift value; Preferably, the gas detection device further comprises a data storage module, the data storage module being electrically connected to the data processing module and configured to store the frequency drift value, form data, and establish a database; Preferably, the gas detection device further comprises a data comparison module, which is electrically connected to the data processing module and the data storage module, and is used to compare the test information with the data in the database and output the test results.

6. The gas detection device according to any one of claims 1 to 5, characterized in that: The gas detection device further includes a housing support structure; the housing support structure includes a head, a middle portion, and a tail portion; the head portion has a head accommodating space for accommodating the light source, and the tail portion has a tail accommodating space for accommodating the gas detection module; The middle portion is hollowed out to form the air chamber; Preferably, the gas detection device further comprises a battery, which is disposed in the head receiving space and is used to power the light source; Preferably, the outer surface contour of the head facing the environment to be retrieved is an arc or streamlined shape, so as to cushion the impact of fluid in the environment to be retrieved.

7. A method for detecting gas types and concentrations, characterized in that: The detection method uses the gas detection device according to any one of claims 1 to 4, and the detection method includes: According to the number of gas detection modules in the gas detection device being n, the gas detection modules and the corresponding target gases are numbered from 1 to n, where n≥1; The gas detection device is placed in a simulated environment, the light source is turned on, and a simulated detection is performed. The initial atmosphere in the simulated environment does not contain the target gas. Then each target gas is introduced into the simulated environment separately, and the concentration of the target gas is used as the horizontal axis x. n , obtain the frequency drift value of the bulk acoustic wave resonator in each gas detection module as the vertical coordinate y n , with data [x n ,y1,y2,…,y n ]Build a database; Place the gas detection device in the environment to be detected, turn on the light source, and perform a working test; record the frequency drift value Y of the bulk acoustic wave resonator in each gas detection module at the test time point t. n , forming the test information [t,Y1,Y2,…,Y n ]; the test information [t,Y1,Y2,…,Y n ] into the database, so that Y n with y n Corresponding, matching the corresponding data [x n ,y1,y2,…,y n ], output the concentration x of the target gas numbered n at time t n .

8. The method for detecting gas types and concentrations according to claim 7, characterized in that: The detection method further comprises the step of converting the data [x n ,y1,y2,…,y n ] is processed into a statistical graph with shape features and / or position features, and a visual database is established with the statistical graph; the test information [t, Y1, Y2, …, Y n ] is processed into a corresponding statistical graph, substituted into the visualization database, and matched with the corresponding data [x n ,y1,y2,…,y n ] to form a statistical chart, outputting the concentration x of the target gas numbered n at time t n .

9. The method for detecting gas types and concentrations according to claim 8, characterized in that: The statistical graph includes at least one of a scatter plot, a line graph, a column graph, a bar graph, a pie chart or an area graph; Preferably, the statistical graph is a bar graph, and the data [x n ,y1,y2,…,y n ]Form each x n Corresponding barcode, test information [t,Y1,Y2,…,Y n ] forms the barcode corresponding to each moment t.

10. Use of the gas detection device according to any one of claims 1 to 4, characterized in that: The applications include detecting leaks of natural gas, coal gas or industrial hazardous gases.

Images