WO2022213584A1 - 一种基于单悬臂梁的差分式光声光谱气体检测装置 - Google Patents

一种基于单悬臂梁的差分式光声光谱气体检测装置 Download PDF

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WO2022213584A1
WO2022213584A1 PCT/CN2021/126893 CN2021126893W WO2022213584A1 WO 2022213584 A1 WO2022213584 A1 WO 2022213584A1 CN 2021126893 W CN2021126893 W CN 2021126893W WO 2022213584 A1 WO2022213584 A1 WO 2022213584A1
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photoacoustic
cantilever beam
processing module
signal processing
photoacoustic cell
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PCT/CN2021/126893
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French (fr)
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王邸博
廖建平
熊佳明
高帆
黄之明
陈宇飞
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南方电网科学研究院有限责任公司
中国南方电网有限责任公司超高压输电公司检修试验中心
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Publication of WO2022213584A1 publication Critical patent/WO2022213584A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/1702—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N19/00—Investigating materials by mechanical methods
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/39—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using tunable lasers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
    • G01N21/45—Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/1702—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids
    • G01N2021/1704—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids in gases
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/39—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using tunable lasers
    • G01N2021/391—Intracavity sample
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
    • G01N21/45—Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods
    • G01N2021/451—Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods for determining the optical absorption

Definitions

  • the invention relates to the technical field of trace gas detection, in particular to a differential photoacoustic spectroscopy gas detection device based on a single cantilever beam.
  • Photoacoustic spectroscopy is a spectroscopic technique based on the photoacoustic (PA) effect. After gas molecules absorb light of a specific wavelength, they are excited to a high-energy state, and gas molecules in a high-energy state release energy by non-radiative transition to a low-energy state. The heat released by the gas after modulated light irradiation is also periodic, causing the gas cycle Sexual expansion produces sound waves.
  • the application of photoacoustic spectroscopy technology in the field of gas detection has good long-term stability, high detection sensitivity, no gas sample consumption, such as carrier gas, standard gas, short detection time, convenient on-site detection and suitable for detection of various gas components, etc. advantage.
  • the published Chinese patent application CN112161932A provides a gas decomposition component detection device based on double cantilever enhanced photoacoustic spectroscopy, which uses two silicon micro-cantilevers to detect the gas to be measured in the same photoacoustic cell, This will cause both cantilevers to be affected by the pressure generated by the flow of the gas to be measured, resulting in higher systematic errors and lower detection sensitivity.
  • the technical problem to be solved by the embodiments of the present invention is to provide a differential photoacoustic spectroscopy gas detection device based on a single cantilever beam, which effectively reduces the system error and improves the detection sensitivity through the design and differential processing of the single cantilever beam.
  • an embodiment of the present invention provides a differential photoacoustic spectroscopy gas detection device based on a single cantilever beam, including a black body radiator, a chopper, a transparent glass, a first photoacoustic cell, and a second photoacoustic Cell, silicon micro-cantilever, laser interferometer, differential signal processing module and host computer;
  • the laser beam emitted by the black body radiator is divided into two beams after being modulated by the chopper, and is respectively injected into the first photoacoustic cell through the transparent glass located at the end of the first photoacoustic cell and the end of the second photoacoustic cell.
  • the photoacoustic pool and the second photoacoustic pool are respectively injected into the first photoacoustic cell through the transparent glass located at the end of the first photoacoustic cell and the end of the second photoacoustic cell.
  • the silicon micro-cantilever beam is arranged at the connection between the first photoacoustic cell and the second photoacoustic cell;
  • the first photoacoustic cell is divided into a first sample chamber and a first detection chamber, and the first sample chamber and the first detection chamber are isolated from each other, and the first detection chamber is A laser interferometer is installed, the laser interferometer is connected with the input end of the differential signal processing module, and the output end of the differential signal processing module is connected with the host computer;
  • the second photoacoustic cell is divided into a second sample chamber and a second detection chamber, and the second sample chamber and the second detection chamber are isolated from each other, and an air inlet is provided on the second photoacoustic cell and air outlet.
  • the first sample chamber and the first detection chamber are isolated by transparent glass; the second sample chamber and the second detection chamber are isolated by transparent glass .
  • the laser interferometer includes a laser light source, a beam splitter, a first detector and a second detector;
  • the laser light emitted by the laser light source is deflected by the beam splitter, passes through the light-transmitting glass located in the first detection chamber, and is reflected by the silicon micro-cantilever beam, and then irradiates the first detector. and on the second detector.
  • the differential signal processing module includes a first differential signal processing module and a second differential signal processing module; the input end of the first differential signal processing module is connected to the first detector, and the The output end of the first differential signal processing module is connected to the upper computer; the input end of the second differential signal processing module is connected to the second detector, and the output end of the second differential signal processing module is connected to the The upper computer is connected.
  • the silicon micro-cantilever beam is precisely processed on the insulating substrate wafer silicon and etched on both sides.
  • the sensitivity of the silicon microcantilever is negatively correlated with the spring constant of the silicon microcantilever, and the smaller the spring constant of the silicon microcantilever, the higher the sensitivity of the silicon microcantilever ; the spring constant of the silicon micro-cantilever is given by the formula calculated,
  • E y is the Young's modulus of the cantilever beam material
  • ⁇ is the free end winding of the cantilever beam
  • t is the thickness of the cantilever beam material
  • l is the length of the cantilever beam material.
  • the first photoacoustic cell and the second photoacoustic cell are both non-resonant photoacoustic cells.
  • the beneficial effect of the differential photoacoustic spectroscopy gas detection device based on a single cantilever beam is that the laser beam emitted by the blackbody radiator is modulated by the chopper.
  • the silicon micro-cantilever beam is set at the connection between the first photoacoustic cell and the second photoacoustic cell;
  • the first photoacoustic cell is divided into a first sample chamber and a first detection chamber, and the first sample chamber The chamber and the first detection chamber are isolated from each other, a laser interferometer is installed on the first detection chamber, the laser interferometer is connected to the input end of the differential signal processing module, and the differential signal processing module
  • the output end of the photoacoustic cell is connected to the host computer;
  • the second photoacoustic cell is divided into a second sample chamber and a second detection chamber, and the second sample chamber and the second detection chamber are isolated from each other , and the second photoacoustic pool is provided with an air inlet and an air outlet.
  • FIG. 1 is a schematic structural diagram of a preferred embodiment of a single cantilever-based differential photoacoustic spectroscopy gas detection device provided by the present invention
  • FIG. 2 is a schematic structural diagram of a silicon micro-cantilever in a differential photoacoustic spectroscopy gas detection device based on a single cantilever provided by the present invention.
  • FIG. 1 is a schematic structural diagram of a preferred embodiment of a single cantilever-based differential photoacoustic spectroscopy gas detection device provided by the present invention.
  • the single-cantilever-based differential photoacoustic spectroscopy gas detection device includes a blackbody radiator 1, a chopper 2, a light-transmitting glass 3, a first photoacoustic cell 4, a second photoacoustic cell 5, and a silicon micro-cantilever beam. 6.
  • the laser beam emitted by the black body radiator 1 is divided into two beams after being modulated by the chopper 2, and respectively passes through the transparent beams located at the end of the first photoacoustic cell 4 and the end of the second photoacoustic cell 5.
  • the optical glass 3 is injected into the first photoacoustic cell 4 and the second photoacoustic cell 5;
  • the silicon micro-cantilever beam 6 is arranged at the connection between the first photoacoustic cell 4 and the second photoacoustic cell 5;
  • the first photoacoustic cell 4 is divided into a first sample chamber 41 and a first detection chamber 42, and the first sample chamber 41 and the first detection chamber 42 are isolated from each other.
  • a detection chamber 42 is installed with a laser interferometer 7 , the laser interferometer 7 is connected to the input end of the differential signal processing module 8 , and the output end of the differential signal processing module 8 is connected to the host computer 9 connect;
  • the second photoacoustic cell 5 is divided into a second sample chamber 51 and a second detection chamber 52, and the second sample chamber 51 and the second detection chamber 52 are isolated from each other, and the second photoacoustic cell 5 is provided with an air inlet 10 and an air outlet 11.
  • an embodiment of the present invention provides a differential photoacoustic spectrum gas detection device based on a single cantilever beam, including a black body radiator, a chopper, a transparent glass, a first photoacoustic cell, a second photoacoustic cell, A silicon micro-cantilever beam, a laser interferometer, a differential signal processing module and a host computer; the laser beam emitted by the black body radiator is modulated by the chopper and divided into two beams, which pass through the end of the first photoacoustic cell respectively.
  • the transparent glass at the end of the second photoacoustic pool is injected into the first photoacoustic pool and the second photoacoustic pool; the silicon micro-cantilever beam is arranged in the first photoacoustic pool and the second photoacoustic pool
  • the gas to be tested in the first detection chamber and the second detection chamber interacts with the nitrogen gas in the first sample chamber and a small amount of the gas to be tested in the second sample chamber respectively due to periodic infrared light
  • the effect produces a photoacoustic effect, causing vibration of the silicon microcantilever
  • the first photoacoustic cell is divided into a first sample chamber and a first detection chamber, and the first sample chamber and the first The detection chambers are isolated from each other, a laser interferometer is installed on the first detection chamber, the laser interferometer is connected to the input end of the differential signal processing module, and the output end of the differential signal processing module is connected to the The upper computer is connected;
  • the second photoacoustic cell is divided into a second
  • the black body radiator compared with the traditional laser light source, the black body radiator has the advantages of strong optical signal, high conversion efficiency, wider wavelength range, higher gas absorption light intensity, and more measurable gas types. Therefore, the embodiment of the present invention uses a black body radiator as a light source, which has a wider wavelength range, a larger gas absorption light intensity, and more types of measurable gases compared with the light source selection in the prior art.
  • the laser interferometer in this embodiment usually adopts a miniature Michelson laser interferometer, which is used to measure the electrical signal of the movement of the cantilever beam.
  • the light-transmitting glass in this embodiment plays the role of light-transmitting and sealing, and has good light-transmitting and sealing properties, which can prevent the gas in the sample chamber from entering the detection chamber and affect the movement of the cantilever beam.
  • first sample chamber 41 and the first detection chamber 42 are isolated by the transparent glass 3; the second sample chamber 51 and the second detection chamber 52 is isolated by light-transmitting glass 3 .
  • the embodiment of the present invention adopts two photoacoustic cells, and each photoacoustic cell is divided into two symmetrical parts by transparent glass, namely the sample chamber and the detection chamber, and the sample chamber and the detection chamber are divided into two parts. It is completely airtightly isolated between the sample chambers to prevent the gas in the sample chamber from entering the detection chamber and affecting the movement of the cantilever beam.
  • the laser interferometer 7 includes a laser light source 71, a beam splitter 72, a first detector 73 and a second detector 74;
  • the laser light emitted by the laser light source 71 is deflected by the beam splitter 72, passes through the light-transmitting glass 3 located in the first detection chamber 42, and is reflected by the silicon micro-cantilever beam 6, and then irradiates the laser beam. on the first detector 73 and the second detector 74 .
  • the laser light emitted by the laser light source passes through the light-transmitting glass located in the first detection chamber, and then is reflected by the silicon micro-cantilever beam, and then irradiates the first detector and the second detector.
  • the differential signal processing module processes the voltage data measured by the first detector and the second detector in the miniature Michelson laser interferometer, obtains a voltage signal proportional to the displacement of the free end of the cantilever beam, and converts it into a digital signal for output to the host computer for processing.
  • the beam splitter can achieve better processing and reception of light wave signals.
  • the differential signal processing module 8 includes a first differential signal processing module 81 and a second differential signal processing module 82; the input end of the first differential signal processing module 81 is connected to the first detection module The output terminal of the first differential signal processing module 71 is connected to the upper computer 9; the input terminal of the second differential signal processing module 82 is connected to the second detector 74, so the The output end of the second differential signal processing module 82 is connected to the upper computer 9 .
  • the first differential signal processing module receives and processes the voltage data measured by the first detector in the laser interferometer
  • the second differential signal processing module receives and processes the voltage data measured by the second detector in the laser interferometer , obtain a voltage signal proportional to the displacement of the free end of the cantilever beam, and convert it into a digital signal and output it to the host computer.
  • the silicon micro-cantilever beam 6 is precisely processed on the insulating substrate wafer silicon and etched on both sides.
  • the cantilever beam when the surrounding air pressure changes, the cantilever beam will bend non-stretchably. Therefore, compared with the elastic diaphragm condenser microphone, the silicon micro-cantilever beam microphone is more sensitive to changes in air pressure.
  • the sensitivity of the silicon micro-cantilever beam 6 is negatively correlated with the spring constant of the silicon micro-cantilever beam, and the smaller the spring constant of the silicon micro-cantilever beam, the higher the sensitivity of the silicon micro-cantilever beam;
  • the spring constant of the silicon microcantilever is given by the formula calculated,
  • E y is the Young's modulus of the cantilever beam material
  • ⁇ is the free end winding of the cantilever beam
  • t is the thickness of the cantilever beam material
  • l is the length of the cantilever beam material.
  • FIG. 2 is a schematic structural diagram of a silicon micro-cantilever beam in a differential photoacoustic spectroscopy gas detection device based on a single cantilever beam provided by the present invention.
  • the spring constant of the cantilever can characterize the corresponding sensitivity of the cantilever. The smaller the spring constant of the cantilever, the higher the sensitivity of the cantilever.
  • the spring constant of a cantilever beam is given by the formula calculated,
  • E y is the Young's modulus of the cantilever beam material
  • ⁇ is the free end winding of the cantilever beam
  • t is the thickness of the cantilever beam material
  • l is the length of the cantilever beam material.
  • the spring constant of the cantilever beam is related to the length-thickness ratio of the cantilever beam.
  • the thickness t of the cantilever beam material is preferably 5 ⁇ m, and the length l of the cantilever beam material is preferably 4 mm.
  • the selection of the cantilever beam needs to be determined according to the actual situation of the experimental device (such as the angle of fixing the cantilever beam, the size of the space at the cantilever beam fixing device), and the embodiment of the present invention provides a cantilever beam with better sensitivity
  • the structure has a higher aspect ratio and therefore has a smaller spring constant k, which can make the cantilever beam respond more sensitively.
  • the first photoacoustic cell 4 and the second photoacoustic cell 5 are both non-resonant photoacoustic cells.
  • the differential photoacoustic spectroscopy gas detection device based on the single cantilever beam provided by the embodiment of the present invention
  • the first detection chamber and the two ends of the rotating mirror of the silicon micro-cantilever beam are respectively connected, and the photoacoustic cell is airtight with each other.
  • Open the air inlet nitrogen gas is introduced into the first sample chamber, a small amount of gas to be tested is introduced into the second sample chamber, and highly soluble gas to be tested is introduced into both the first detection chamber and the second detection chamber.
  • the black body radiator emits radiation, which is modulated into periodic infrared light by its optical chopper, closing the air inlet.
  • the gas to be tested in the first detection chamber and the second detection chamber interact with nitrogen gas in the first sample chamber and a small amount of gas to be tested in the second sample chamber respectively due to periodic infrared light interaction to produce a photoacoustic effect , causing the vibration of the silicon microcantilever.
  • the micro Michelson interferometer is used for measurement and the differential signal is preprocessed by the differential signal processing module.
  • the laser light emitted by the laser light source in the miniature Michelson laser interferometer is deflected by the beam splitter, passes through the light-transmitting glass, is reflected by the silicon micro-cantilever beam, and then passes through the light-transmitting glass to illuminate the detector.
  • the differential signal processing module processes the voltage data measured by the detector in the miniature Michelson laser interferometer to obtain a voltage signal proportional to the displacement of the free end of the cantilever beam, and converts it into a digital signal and outputs it to the host computer.
  • An embodiment of the present invention provides a differential photoacoustic spectroscopy gas detection device based on a single cantilever beam.
  • the laser beam emitted by the blackbody radiator is modulated by the chopper and divided into two beams, respectively passing through the The light-transmitting glass at the end of the first photoacoustic pool and the end of the second photoacoustic pool is injected into the first photoacoustic pool and the second photoacoustic pool;
  • the silicon micro-cantilever beam is arranged on the first photoacoustic pool and all the the connection of the second photoacoustic cell;
  • the first photoacoustic cell is divided into a first sample chamber and a first detection chamber, and the first sample chamber and the first detection chamber are mutually isolation, a laser interferometer is installed on the first detection chamber, the laser interferometer is connected to the input end of the differential signal processing module, and the output end of the differential signal processing module is connected to the host computer
  • the second photoacoustic cell is

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Abstract

本发明公开了一种基于单悬臂梁的差分式光声光谱气体检测装置，所述装置包括：黑体辐射器发出的激光光束经过斩波器调制后分为两束，分别通过位于第一光声池端部和第二光声池端部的透光玻璃射入第一光声池和第二光声池内；硅微悬臂梁设置于第一光声池和第二光声池的连通处；第一光声池分为第一样品腔室和第一检测腔室，且第一样品腔室和第一检测腔室相互隔离，第一检测腔室上安装有激光干涉仪，激光干涉仪与差分信号处理模块的输入端相连接，差分信号处理模块的输出端与上位机相连接；第二光声池分为第二样品腔室和第二检测腔室，且第二样品腔室和第二检测腔室相互隔离。本发明通过单悬臂梁的设计和差分处理有效减少了系统误差，提高了检测灵敏度。

Description

一种基于单悬臂梁的差分式光声光谱气体检测装置 技术领域
本发明涉及微量气体检测技术领域，尤其涉及一种基于单悬臂梁的差分式光声光谱气体检测装置。
背景技术
光声光谱技术(PAS)是基于光声(PA)效应的一种光谱技术。气体分子吸收特定波长的光后，被激发至高能态，高能态气体分子通过无辐射跃迁至低能态释放能量，经过调制的光照射后的气体，释放的热量也是周期性的，从而引起气体周期性的膨胀，产生声波。将光声光谱技术应用于气体检测领域，具有长期稳定性好、检测灵敏度高、不消耗气样，如载气、标气、检测时间短、便于现场检测以及适于多种气体成分的检测等优点。传统的光声光谱检测中，气体分子吸收光能发生无辐射跃迁产生的声波，通常被一个驻极体传声器转换为电信号。根据光声光谱学的原理，光声测量的灵敏度正比于声波探测器的灵敏度。相比于电容式传声器和膜片式光纤传声器，硅微悬臂梁传声器具有低频响应好、灵敏度高和动态响应范围大等优点。
已公开的中国专利申请CN112161932A所提供的一种基于双悬臂梁增强型光声光谱的气体分解组分检测装置，采用两个硅微悬臂梁对同一个光声池中的待测气体进行检测，这样会造成两个悬臂梁都会受到待测气体流动产生的压强的影响，从而导致产生较高的系统误差，检测灵敏度较低。
发明内容
本发明实施例所要解决的技术问题在于，提供一种基于单悬臂梁的差分式光 声光谱气体检测装置，通过单悬臂梁的设计和差分处理有效减少了系统误差，提高了检测灵敏度。
为了实现上述目的，本发明实施例提供了一种基于单悬臂梁的差分式光声光谱气体检测装置，包括黑体辐射器、斩波器、透光玻璃、第一光声池、第二光声池、硅微悬臂梁、激光干涉仪、差分信号处理模块和上位机；
所述黑体辐射器发出的激光光束经过所述斩波器调制后分为两束，分别通过位于所述第一光声池端部和所述第二光声池端部的透光玻璃射入第一光声池和第二光声池内；
所述硅微悬臂梁设置于所述第一光声池和所述第二光声池的连通处；
所述第一光声池分为第一样品腔室和第一检测腔室，且所述第一样品腔室和所述第一检测腔室相互隔离，所述第一检测腔室上安装有激光干涉仪，所述激光干涉仪与所述差分信号处理模块的输入端相连接，所述差分信号处理模块的输出端与所述上位机相连接；
所述第二光声池分为第二样品腔室和第二检测腔室，且所述第二样品腔室和所述第二检测腔室相互隔离，第二光声池上设有进气口和出气口。
作为上述方案的改进，所述第一样品腔室和所述第一检测腔室通过透光玻璃进行隔离；所述第二样品腔室和所述第二检测腔室通过透光玻璃进行隔离。
作为上述方案的改进，所述激光干涉仪包括激光光源、分束器、第一探测器和第二探测器；
所述激光光源发出的激光经过所述分束器转向后，透过位于所述第一检测腔室的透光玻璃，并经所述硅微悬臂梁反射后，照射在所述第一探测器和所述第二探测器上。
作为上述方案的改进，所述差分信号处理模块包括第一差分信号处理模块和 第二差分信号处理模块；所述第一差分信号处理模块的输入端与所述第一探测器相连接，所述第一差分信号处理模块的输出端与所述上位机相连接；所述第二差分信号处理模块的输入端与所述第二探测器相连接，所述第二差分信号处理模块的输出端与所述上位机相连接。
作为上述方案的改进，所述硅微悬臂梁采用精密加工在绝缘衬底晶片硅上且双面蚀刻而成。
作为上述方案的改进，所述硅微悬臂梁的灵敏度与所述硅微悬臂梁的弹簧常数呈负相关，所述硅微悬臂梁的弹簧常数越小，所述硅微悬臂梁的灵敏度越高；所述硅微悬臂梁的弹簧常数通过公式
Figure PCTCN2021126893-appb-000001
计算得到，
其中，E y为悬臂梁材料的杨氏模量，ω为悬臂梁自由端绕度，t为悬臂梁材料的厚度，l为悬臂梁材料的长度。
作为上述方案的改进，所述第一光声池和所述第二光声池均为非谐振式光声池。
相对于现有技术，本发明实施例提供的一种基于单悬臂梁的差分式光声光谱气体检测装置的有益效果在于：通过所述黑体辐射器发出的激光光束经过所述斩波器调制后分为两束，分别通过位于所述第一光声池端部和所述第二光声池端部的透光玻璃射入第一光声池和第二光声池内；所述硅微悬臂梁设置于所述第一光声池和所述第二光声池的连通处；所述第一光声池分为第一样品腔室和第一检测腔室，且所述第一样品腔室和所述第一检测腔室相互隔离，所述第一检测腔室上安装有激光干涉仪，所述激光干涉仪与所述差分信号处理模块的输入端相连接，所述差分信号处理模块的输出端与所述上位机相连接；所述第二光声池分为第二样品腔室和第二检测腔室，且所述第二样品腔室和所述第二检测腔室相互隔离，第二光声池上设有进气口和出气口。本发明实施例通过单悬臂梁的设计和差分处理有效减少了系统误差，提高了检测灵敏度。
附图说明
图1是本发明提供的一种基于单悬臂梁的差分式光声光谱气体检测装置的一个优选实施例的结构示意图；
图2是本发明提供的一种基于单悬臂梁的差分式光声光谱气体检测装置中硅微悬臂梁的结构示意图。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
请参阅图1，图1是本发明提供的一种基于单悬臂梁的差分式光声光谱气体检测装置的一个优选实施例的结构示意图。所述基于单悬臂梁的差分式光声光谱气体检测装置，包括黑体辐射器1、斩波器2、透光玻璃3、第一光声池4、第二光声池5、硅微悬臂梁6、激光干涉仪7、差分信号处理模块8和上位机9；
所述黑体辐射器1发出的激光光束经过所述斩波器2调制后分为两束，分别通过位于所述第一光声池4端部和所述第二光声池5端部的透光玻璃3射入第一光声池4和第二光声池5内；
所述硅微悬臂梁6设置于所述第一光声池4和所述第二光声池5的连通处；
所述第一光声池4分为第一样品腔室41和第一检测腔室42，且所述第一样品腔室41和所述第一检测腔室42相互隔离，所述第一检测腔室42上安装有激光干涉仪7，所述激光干涉仪7与所述差分信号处理模块8的输入端相连接，所述差分信号处理模块8的输出端与所述上位机9相连接；
所述第二光声池5分为第二样品腔室51和第二检测腔室52，且所述第二样 品腔室51和所述第二检测腔室52相互隔离，第二光声池5上设有进气口10和出气口11。
具体的，本发明实施例提供的一种基于单悬臂梁的差分式光声光谱气体检测装置，包括黑体辐射器、斩波器、透光玻璃、第一光声池、第二光声池、硅微悬臂梁、激光干涉仪、差分信号处理模块和上位机；所述黑体辐射器发出的激光光束经过所述斩波器调制后分为两束，分别通过位于所述第一光声池端部和所述第二光声池端部的透光玻璃射入第一光声池和第二光声池内；所述硅微悬臂梁设置于所述第一光声池和所述第二光声池的连通处，当第一检测腔室和第二检测腔室中的待测气体分别与第一样品腔室中的氮气和第二样品腔室中的少量待测气体由于周期性红外光相互作用产生光声效应，引起硅微悬臂梁的振动；所述第一光声池分为第一样品腔室和第一检测腔室，且所述第一样品腔室和所述第一检测腔室相互隔离，所述第一检测腔室上安装有激光干涉仪，所述激光干涉仪与所述差分信号处理模块的输入端相连接，所述差分信号处理模块的输出端与所述上位机相连接；所述第二光声池分为第二样品腔室和第二检测腔室，且所述第二样品腔室和所述第二检测腔室相互隔离，第二光声池上设有进气口和出气口。
需要说明的是，黑体辐射器相比传统的激光光源，具有光信号强大、转化效率高、波长范围更广，气体吸收光强度更大、可测量的气体种类更多等优势。因此，本发明实施例采用黑体辐射器作为光源，相比于现有技术中的的光源选择，波长范围更广，气体吸收光强度更大，可测量的气体种类更多。本实施例中的激光干涉仪通常采用微型迈克尔逊激光干涉仪，用于测量悬臂梁运动的电信号。本实施例中的透光玻璃起到透光和密封的作用，具有良好的透光性和密封性，能够避免样品腔室中的气体进入检测腔室，影响悬臂梁的运动。
在另一个优选实施例中，所述第一样品腔室41和所述第一检测腔室42通过透光玻璃3进行隔离；所述第二样品腔室51和所述第二检测腔室52通过透光玻璃3进行隔离。
具体的，本发明实施例采用两个光声池，并且通过透光玻璃将每个光声池分为对称的两部分，即样品腔室和检测腔室，且样品腔室和检测腔室之间完全气密隔离，避免样品腔室中的气体进入检测腔室，影响悬臂梁的运动。
在又一个优选实施例中，所述激光干涉仪7包括激光光源71、分束器72、第一探测器73和第二探测器74；
所述激光光源71发出的激光经过所述分束器72转向后，透过位于所述第一检测腔室42的透光玻璃3，并经所述硅微悬臂梁6反射后，照射在所述第一探测器73和所述第二探测器74上。
具体的，激光光源发出的激光经过分束器转向后，透过位于第一检测腔室的透光玻璃，然后经硅微悬臂梁反射后，照射在第一探测器和第二探测器上。差分信号处理模块对微型迈克尔逊激光干涉仪中第一探测器和第二探测器测得的电压数据进行处理，得到与悬臂梁自由末端位移成比例的电压信号，并将之转换为数字信号输出至上位机中进行处理。其中，分束器能实现光波信号更好的处理与接收。
在又一个优选实施例中，所述差分信号处理模块8包括第一差分信号处理模块81和第二差分信号处理模块82；所述第一差分信号处理模块81的输入端与所述第一探测器73相连接，所述第一差分信号处理模块71的输出端与所述上位机9相连接；所述第二差分信号处理模块82的输入端与所述第二探测器74相连接，所述第二差分信号处理模块82的输出端与所述上位机9相连接。
具体的，第一差分信号处理模块接收激光干涉仪中第一探测器测得的电压数据并进行处理，第二差分信号处理模块接收激光干涉仪中第二探测器测得的电压数据并进行处理，得到与悬臂梁自由末端位移成比例的电压信号，并将之转换为数字信号输出至上位机。
作为优选方案，所述硅微悬臂梁6采用精密加工在绝缘衬底晶片硅上且双面 蚀刻而成。
需要说明的是，当周围气压变化时，悬臂梁会发生非伸缩性弯曲，因此，相比于具有弹性的膜片式电容传声器，硅微悬臂梁传声器对气压的变化更为敏感。
作为优选方案，所述硅微悬臂梁6的灵敏度与所述硅微悬臂梁的弹簧常数呈负相关，所述硅微悬臂梁的弹簧常数越小，所述硅微悬臂梁的灵敏度越高；所述硅微悬臂梁的弹簧常数通过公式
Figure PCTCN2021126893-appb-000002
计算得到，
其中，E y为悬臂梁材料的杨氏模量，ω为悬臂梁自由端绕度，t为悬臂梁材料的厚度，l为悬臂梁材料的长度。
具体的，请参阅图2，图2是本发明提供的一种基于单悬臂梁的差分式光声光谱气体检测装置中硅微悬臂梁的结构示意图。悬臂梁的弹簧常数能够表征悬臂相应的灵敏度，悬臂梁的弹簧常数越小，则悬臂梁的灵敏度越高。悬臂梁的弹簧常数通过公式
Figure PCTCN2021126893-appb-000003
计算得到，
其中，E y为悬臂梁材料的杨氏模量，ω为悬臂梁自由端绕度，t为悬臂梁材料的厚度，l为悬臂梁材料的长度。
悬臂梁的弹簧常数与悬臂梁的长厚比有关，悬臂梁的长厚比越大，则悬臂梁的弹簧常数越小，悬臂梁的灵敏度越高。本实施例中悬臂梁材料的厚度t优选为5μm，悬臂梁材料的长度l优选为4mm。
需要说明的是，悬臂梁的选取需要根据实验装置的实际情况(如固定悬臂梁的角度，悬臂梁固定装置处的空间大小)来定，本发明实施例提供了一种灵敏度较优的悬臂梁结构，具有较高的长厚比，因此具有更小的弹簧常数k，能够使得悬臂梁响应更加灵敏。
作为优选方案，所述第一光声池4和所述第二光声池5均为非谐振式光声池。
本发明实施例提供的一种基于单悬臂梁的差分式光声光谱气体检测装置在使用时，第一检测腔室与硅微悬臂梁的转镜两端分别相通，光声池内相互气密。打开进气口，第一样品腔室通入氮气，第二样品腔室通入少量的待测气体，第一检测腔室和第二检测腔室均通入高溶度的待测气体。黑体辐射器发出辐射，经其带有的光学斩波器调制成周期性红外光，关闭进气口。第一检测腔室和第二检测腔室中的待测气体分别与第一样品腔室中的氮气和第二样品腔室中的少量待测气体由于周期性红外光相互作用产生光声效应，引起硅微悬臂梁的振动。通过计算悬臂梁处所受到的压力差产生的振动位移，微型迈克尔逊干涉仪进行测量并交由差分信号处理模块进行差分信号预处理。微型迈克尔逊激光干涉仪中激光光源发出的激光，经分束器转向，透过透光玻璃，经硅微悬臂梁反射后，再透过透光玻璃，照射在探测器上。差分信号处理模块对微型迈克尔逊激光干涉仪中探测器测得的电压数据进行处理，得到与悬臂梁自由末端位移成比例的电压信号，并将之转换为数字信号输出至上位机。
本发明实施例提供了一种基于单悬臂梁的差分式光声光谱气体检测装置，通过所述黑体辐射器发出的激光光束经过所述斩波器调制后分为两束，分别通过位于所述第一光声池端部和所述第二光声池端部的透光玻璃射入第一光声池和第二光声池内；所述硅微悬臂梁设置于所述第一光声池和所述第二光声池的连通处；所述第一光声池分为第一样品腔室和第一检测腔室，且所述第一样品腔室和所述第一检测腔室相互隔离，所述第一检测腔室上安装有激光干涉仪，所述激光干涉仪与所述差分信号处理模块的输入端相连接，所述差分信号处理模块的输出端与所述上位机相连接；所述第二光声池分为第二样品腔室和第二检测腔室，且所述第二样品腔室和所述第二检测腔室相互隔离，第二光声池上设有进气口和出气口。本发明实施例通过单悬臂梁的设计和差分处理有效减少了系统误差，提高了检测灵敏度。
以上所述是本发明的优选实施方式，应当指出，对于本技术领域的普通技术 人员来说，在不脱离本发明原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也视为本发明的保护范围。

Claims (7)

  1. 一种基于单悬臂梁的差分式光声光谱气体检测装置，其特征在于，包括黑体辐射器、斩波器、透光玻璃、第一光声池、第二光声池、硅微悬臂梁、激光干涉仪、差分信号处理模块和上位机；
    所述黑体辐射器发出的激光光束经过所述斩波器调制后分为两束，分别通过位于所述第一光声池端部和所述第二光声池端部的透光玻璃射入第一光声池和第二光声池内；
    所述硅微悬臂梁设置于所述第一光声池和所述第二光声池的连通处；
    所述第一光声池分为第一样品腔室和第一检测腔室，且所述第一样品腔室和所述第一检测腔室相互隔离，所述第一检测腔室上安装有激光干涉仪，所述激光干涉仪与所述差分信号处理模块的输入端相连接，所述差分信号处理模块的输出端与所述上位机相连接；
    所述第二光声池分为第二样品腔室和第二检测腔室，且所述第二样品腔室和所述第二检测腔室相互隔离，第二光声池上设有进气口和出气口。
  2. 如权利要求1所述的基于单悬臂梁的差分式光声光谱气体检测装置，其特征在于，所述第一样品腔室和所述第一检测腔室通过透光玻璃进行隔离；所述第二样品腔室和所述第二检测腔室通过透光玻璃进行隔离。
  3. 如权利要求2所述的基于单悬臂梁的差分式光声光谱气体检测装置，其特征在于，所述激光干涉仪包括激光光源、分束器、第一探测器和第二探测器；
    所述激光光源发出的激光经过所述分束器转向后，透过位于所述第一检测腔室的透光玻璃，并经所述硅微悬臂梁反射后，照射在所述第一探测器和所述第二 探测器上。
  4. 如权利要求3所述的基于单悬臂梁的差分式光声光谱气体检测装置，其特征在于，所述差分信号处理模块包括第一差分信号处理模块和第二差分信号处理模块；所述第一差分信号处理模块的输入端与所述第一探测器相连接，所述第一差分信号处理模块的输出端与所述上位机相连接；所述第二差分信号处理模块的输入端与所述第二探测器相连接，所述第二差分信号处理模块的输出端与所述上位机相连接。
  5. 如权利要求4所述的基于单悬臂梁的差分式光声光谱气体检测装置，其特征在于，所述硅微悬臂梁采用精密加工在绝缘衬底晶片硅上且双面蚀刻而成。
  6. 如权利要求5所述的基于单悬臂梁的差分式光声光谱气体检测装置，其特征在于，所述硅微悬臂梁的灵敏度与所述硅微悬臂梁的弹簧常数呈负相关，所述硅微悬臂梁的弹簧常数越小，所述硅微悬臂梁的灵敏度越高；所述硅微悬臂梁的弹簧常数通过公式
    Figure PCTCN2021126893-appb-100001
    计算得到，
    其中，E y为悬臂梁材料的杨氏模量，ω为悬臂梁自由端绕度，t为悬臂梁材料的厚度，l为悬臂梁材料的长度。
  7. 如权利要求1所述的基于单悬臂梁的差分式光声光谱气体检测装置，其特征在于，所述第一光声池和所述第二光声池均为非谐振式光声池。
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