Gas sensor based on non-dispersive infrared detection

Abstract

The invention discloses a gas sensor based on non-dispersive infrared detection. The gas sensor comprises a base, a pipe cap, at least one detection assembly and at least one infrared light source assembly, the pipe cap covers the base, and the outer edge of the pipe cap is fixedly connected with the base; at least one base through hole penetrating through the base is formed in the base; the side wall of each base through hole extends towards one side far away from the pipe cap to form a hollow pipe core; each infrared light source assembly is arranged at one end, facing the pipe cap, in one base through hole in a covering manner, and a cavity in each infrared light source assembly is communicated with one base through hole; air holes are formed in the wall of each pipe core; the pins penetrate through the base, and the tail ends of the pins extend into one side of the infrared light source assembly; and each detection assembly is assembled at one end, far away from the infrared light source assembly, in the tube core and seals the tail end of the tube core. The gas sensor is designed based on the absorption gas chamber integrated structure and the back-through infrared light source assembly, so that the integration difficulty is reduced, and the robustness and stability of the system are improved.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a gas sensor based on non-dispersive infrared detection. Background Art

[0002] In recent years, NDIR (non-dispersive infrared detection) gas sensing technology has been widely used in many fields such as air quality detection, medical breath diagnosis, smart agriculture and gas monitoring in industrial processes. Most of the existing NDIR gas sensors use split components to assemble into product modules through integration and packaging processes. There are great challenges in product consistency and miniaturization, and the stability and robustness of the products need to be further improved. In addition, for some special application scenarios, such as wide-range gas monitoring or mixed multi-gas detection, there is still a lack of high stability and robustness design solutions.

[0003] Generally, NDIR gas sensors are composed of components such as infrared light source, absorption chamber, infrared detector and circuit board. The reflective cover, infrared light source and infrared detector are welded on the circuit board and fixed at both ends of the absorption chamber. Sealing glue is used for pasting and packaging. The overall structure and production process are complicated, which is not conducive to mass production under the condition of ensuring high reliability. The design of non-integrated structure has poor stability and robustness of the sensor, and the consistency and miniaturization are often not ideal, which urgently needs further improvement. In addition, most of the current NDIR gas sensors adopt dual-channel, fixed optical path design, with a narrow detection concentration range, and a single sensor cannot achieve high and low range gas detection. In terms of mixed multi-gas detection, a single or multiple infrared light sources are generally combined with a single or multiple infrared detectors, which have disadvantages such as complex structure, poor robustness and large size. Summary of the invention

[0004] The embodiment of the present invention provides a gas sensor based on non-dispersive infrared detection, aiming to solve the problems of complex structure, poor robustness and large volume of the gas sensor in the prior art method.

[0005] The embodiment of the present application provides a gas sensor based on non-dispersive infrared detection, wherein the gas sensor includes a base, a tube cap, at least one detection component and at least one infrared light source component; The tube cap is covered on the base, and the outer edge of the tube cap is fixedly connected to the base; the base is provided with at least one base through hole penetrating the base; the side wall of each base through hole extends to a side away from the tube cap to form a hollow tube core; Each of the infrared light source components is covered and arranged in one end of a through hole of the base facing the tube cap, and the cavity in the infrared light source component is connected with one through hole of the base; a vent hole is provided on the wall of each tube core; The pin passes through the base and the end thereof extends into one side of the infrared light source assembly, and the heating layer in the infrared light source assembly and the end of the pin are electrically connected via a metal wire; Each of the detection components is assembled at one end of a corresponding tube core away from the infrared light source component, and the end of the tube core is closed; each of the detection components is provided with at least one infrared detector, and each of the infrared detectors is provided with a narrow-band filter at one end facing the infrared light source component; the detection pins electrically connected to each of the infrared detectors extend from the inside of the detection component to the outside.

[0006] The gas sensor based on non-dispersive infrared detection, wherein the infrared light source component is a silicon-based MEMS light source component, a heating metal foil or a metal wire; The silicon-based MEMS light source component is recessed inwardly on one side facing the base through hole to form the cavity. The tube cap is an arc-shaped tube cap with an opening on one side, and the opening of the arc-shaped tube cap faces the base.

[0007] The gas sensor based on non-dispersive infrared detection, wherein the silicon-based MEMS light source assembly mainly includes a silicon substrate, a heating layer and a reflective layer; The silicon substrate is provided with a substrate through hole, the heating layer is attached to a side of the silicon substrate away from the base and covers the substrate through hole to form an inwardly recessed cavity, and the reflective layer is attached to the upper layer of the heating layer.

[0008] In the gas sensor based on non-dispersive infrared detection, the reflective layer is a metal reflective film made of one or more materials selected from Au, Pt, Ag, Al, and Cu.

[0009] The gas sensor based on non-dispersive infrared detection, wherein the infrared light source component is a double-sided silicon-based MEMS light source component, a double-sided silicon-based heating wire or a double-sided ceramic-based heating wire; The double-sided silicon-based MEMS light source assembly is provided with a cavity running through from top to bottom; the tube cap is a tubular tube cap with openings at both ends; One or more openings are provided at one end of the tube cap away from the base, and each opening at the end of the tubular tube cap away from the base is provided with a detection assembly; A metal-plated pad is provided between the double-sided silicon-based MEMS light source assembly and the base. The metal-plated pad is electrically connected to the heating layer of the double-sided silicon-based MEMS light source assembly close to the base. The metal-plated pad is electrically connected to the end of the pin through a metal wire.

[0010] The gas sensor based on non-dispersive infrared detection, wherein the double-sided silicon-based MEMS light source assembly mainly includes a silicon substrate, two heating layers and two infrared radiation material layers; A substrate through hole is provided on the silicon substrate, the two heating layers are respectively bonded to the two sides of the silicon substrate, and the two infrared radiation material layers are respectively bonded to the outer sides of the two heating layers; the heating layers located at the two ends of the substrate through hole and the bonded infrared radiation material layers are combined into an infrared radiation unit, and the infrared radiation unit is suspended at the outer opening of the substrate through hole, and the heating layer in the infrared radiation unit extends outward to form a support arm connected to the heating layer at the outer edge of the substrate through hole.

[0011] The gas sensor based on non-dispersive infrared detection, wherein the infrared radiation material layer is nano-platinum black, nano-black silicon, carbon nanotubes, graphene or an amorphous carbon film doped with metal elements, or is a super surface material based on Au, Al2O3 or Au material, or is a ZnNiP chemical plating layer.

[0012] In the gas sensor based on non-dispersive infrared detection, the silicon substrate is a single crystal silicon substrate or an SOI silicon wafer substrate.

[0013] The gas sensor based on non-dispersive infrared detection, wherein the heating layer comprises a stacked support layer, a heating electrode and an isolation layer; the heating electrode is a metal composite film layer prepared from one or more materials selected from Pt, Au, W, Al, tin nitride, nickel-chromium alloy, MoSi2, or a polysilicon film doped with B by ion implantation; The support layer and the isolation layer are single-layer SiO2 or single-layer Si3N4 or single-layer SiN x , or a composite film layer composed of multiple film layers including SiO2 layer, Si3N4 layer and SiNx layer.

[0014] In the gas sensor based on non-dispersive infrared detection, the inner and outer surfaces of the base are plated with a metal film layer, and the metal film layer is formed by electroplating one or more materials selected from Ni, Au, Al, and Pt.

[0015] The embodiment of the present invention provides a gas sensor based on non-dispersive infrared detection, which includes a base, a tube cap, at least one detection component and at least one infrared light source component; the tube cap is covered on the base, and the outer edge of the tube cap is fixedly connected to the base; the base is provided with at least one base through hole penetrating the base; the side wall of each base through hole extends to the side away from the tube cap to form a hollow tube core; each infrared light source component is covered and arranged in one end of a base through hole facing the tube cap, and the cavity in the infrared light source component is connected to a base through hole; each tube core is provided with an air hole on the wall; the pin penetrates the base and the end extends into one side of the infrared light source component, and the heating layer in the infrared light source component is electrically connected to the end of the pin through a metal wire; each detection component is assembled at one end of a corresponding tube core away from the infrared light source component, and the end of the tube core is sealed. The above-mentioned gas sensor is designed based on the absorption chamber integrated structure and the back-transmitted infrared light source component, and no additional structure is required to fix the infrared light source, which effectively reduces the integration difficulty and volume of the sensor and greatly enhances its stability and system robustness. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0017] Figure 1 A cross-sectional structural diagram of a gas sensor based on non-dispersive infrared detection provided by an embodiment of the present invention; Figure 2 Another cross-sectional structural diagram of a gas sensor based on non-dispersive infrared detection provided by an embodiment of the present invention; Figure 3 Another cross-sectional structural diagram of a gas sensor based on non-dispersive infrared detection provided by an embodiment of the present invention; Figure 4 Another cross-sectional structural diagram of a gas sensor based on non-dispersive infrared detection provided by an embodiment of the present invention; Figure 5 A cross-sectional structural diagram of an infrared light source assembly provided by an embodiment of the present invention; Figure 6 Another cross-sectional structural diagram of an infrared light source assembly provided by an embodiment of the present invention; Figure 7 A three-dimensional structural diagram of a base provided in an embodiment of the present invention; Figure numerals: 3, base; 6, tube cap; 4, detection component; 1, silicon-based MEMS light source component; 2, double-sided silicon-based MEMS light source component; 11, silicon substrate; 101, cavity; 12, heating layer; 13, reflection layer; 21, infrared radiation material layer; 31, tube core; 32, pin; 33, air hole; 41, infrared detector; 42, narrow-band filter; 43, detection pin; 7, metal-plated pad; 8, metal wire. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0020] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present 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. It should also be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0021] See also Figure 1 to Figure 2As shown in the figure, the embodiment of the present application discloses a gas sensor based on non-dispersive infrared detection, wherein the gas sensor includes a base 3, a tube cap 6, at least one detection component 4 and at least one infrared light source component; the tube cap 6 is covered on the base 3, and the outer edge of the tube cap 6 is fixedly connected to the base 3; the base 3 is provided with at least one base through hole penetrating the base 3; the side walls of each base through hole extend to a side away from the tube cap 6 to form a hollow tube core 31; each infrared light source component is covered and arranged in one of the base through holes at one end facing the tube cap 6, and the cavity 101 in the infrared light source component is connected to one of the base through holes ; A vent hole 33 is provided on the wall of each tube core 31; a pin 32 passes through the base 3 and the end thereof extends into one side of the infrared light source assembly, and the heating layer 12 in the infrared light source assembly is electrically connected to the end of the pin 32 through a metal wire 8; each detection assembly 4 is assembled at one end of a corresponding tube core 31 away from the infrared light source assembly, and the end of the tube core 31 is sealed; each detection assembly 4 is provided with at least one infrared detector 41, and each infrared detector 41 is provided with a narrow-band filter 42 at one end thereof facing the infrared light source assembly; a detection pin 43 electrically connected to each infrared detector 41 extends from the inside of the detection assembly 4 to the outside.

[0022] The tube cap 6 is covered on the base 3. The base 3 may be provided with one or more base through holes. The side wall of each base through hole extends to a side away from the tube cap 6 to form a hollow tube core 31. The specific structure is as follows Figure 1 As shown, Figure 1 In the embodiment, a base through hole is provided on the base 3, and the base through hole is extended to form a tube core 31. Each base through hole is covered with an infrared light source component at one end facing the tube cap 6, such as Figure 1 , Figure 2 and Figure 3 In the figure, an infrared light source assembly is arranged to cover one end of a through hole of a base. Figure 4 In FIG. 3 , it is shown that an infrared light source assembly is respectively provided at one end of the plurality of base through holes. A detection assembly 4 is installed at one end of the tube core 31 away from the infrared light source assembly. The detection assembly 4 includes at least one infrared detector 41 and at least one narrow band filter 42. Figure 1 As shown, the detection assembly 4 is equipped with two infrared detectors 41 and two narrow-band filters 42 .

[0023] Specifically, a step can be provided at the edge of the base 3, and the outer edge of the tube cap 6 is embedded in the step, so as to realize the fixed connection between the tube cap 6 and the base 3. The pins 32 provided on the base 3 are used to realize the electrical connection of the infrared light source assembly; the size of the base 3 can be designed and processed according to actual needs, and the inner diameter and outer diameter of the tube core 31 need to be determined according to the size of the infrared light source assembly. The diameter of the metal wire 8 is 15μm~50μm.

[0024] In a specific embodiment, the infrared light source assembly is a silicon-based MEMS light source assembly 1, a heating metal foil or a metal wire; the silicon-based MEMS light source assembly 1 is recessed inwardly toward one side of the base through hole to form the cavity 101, and the tube cap 6 is an arc-shaped tube cap 6 with one side open, and the opening of the arc-shaped tube cap 6 faces the base 3. Specifically, as Figure 5 As shown, the silicon-based MEMS light source assembly 1 mainly includes a silicon substrate 11, a heating layer 12 and a reflective layer 13; the silicon substrate 11 is provided with a substrate through hole, the heating layer 12 is attached to the side of the silicon substrate 11 away from the base 3 and covers the substrate through hole to form an inwardly concave cavity 101, and the reflective layer 13 is attached to the upper layer of the heating layer 12. The reflective layer 13 is a metal reflective film made of one or more materials selected from Au, Pt, Ag, Al, and Cu.

[0025] like Figure 1 As shown, the tube cap 6 is an arc-shaped tube cap 6 with one side open, and only one detection component 4 is assembled in one tube core 31 at one end away from the infrared light source component. The side of the silicon-based MEMS light source component 1 facing the base through hole is recessed inward to form a cavity 101, and the cavity 101 is connected to the base through hole. Specifically, the silicon-based MEMS light source component 1 includes a silicon substrate 11, a heating layer 12 and a reflective layer 13. The heating layer 12 radiates infrared light outward by electrothermal heating. The infrared light is reflected based on the enhanced reflection effect of the reflective layer 13 and radiates outward from the cavity 101 of the silicon substrate 11, thereby forming a back-transmitted silicon-based MEMS infrared light source. Specifically, the cross-section of the cavity 101 of the silicon substrate 11 can be set to a trapezoidal or rectangular shape, and the opening size of the cavity 101 can be set to be larger than the inner diameter of the tube core 31. This back-transmitted silicon-based MEMS infrared light source setting structure can effectively reduce the difficulty of device integration and assembly.

[0026] The processing method of the silicon-based MEMS light source component 1 and the reflective layer 13 therein is not specifically limited in the present invention, and the size can be designed and processed according to actual needs. In addition, the silicon-based MEMS light source component 1 can also be replaced by a heating metal foil or a metal wire to realize the application function of radiating infrared light outward based on the principle of electrothermal heating.

[0027] In another specific embodiment, the infrared light source component is a double-sided silicon-based MEMS light source component 2, a double-sided silicon-based heating wire or a double-sided ceramic-based heating wire; the double-sided silicon-based MEMS light source component 2 is provided with a cavity 101 running through it from top to bottom; the tube cap 6 is a tubular tube cap 6 with openings at both ends; one or more openings are provided at the end of the tube cap 6 away from the base 3, and a detection component 4 is provided at each opening at the end of the tubular tube cap 6 away from the base 3; a metal-plated pad 7 is provided between the double-sided silicon-based MEMS light source component 2 and the base 3, and the metal-plated pad 7 is electrically connected to the heating layer 12 of the double-sided silicon-based MEMS light source component 2 close to the base 3, and the metal-plated pad 7 is electrically connected to the end of the pin 32 through a metal wire 8.

[0028] like Figures 2 to 4 As shown, in order to further improve the ability to detect different gas components (such as detecting nitric oxide gas and carbon dioxide gas at the same time), the infrared light source component can be configured as a double-sided silicon-based MEMS light source component 2. The double-sided silicon-based MEMS light source component 2 is provided with a cavity 101 that runs through the upper and lower parts, and the tube cap 6 is a tubular tube cap 6 with openings at both ends. The tube cap 6 can be provided with an opening at one end away from the base 3, and the structure is as follows Figure 2 and Figure 3 As shown; the end of the tube cap 6 away from the base 3 may be provided with a plurality of openings, the structure as Figure 4 As shown. A detection assembly 4 is provided at each opening of the tubular cap 6 away from the base 3. The metal-plated pad 7 is used for the electrical connection of the heating layer 12 on the side of the double-sided silicon-based MEMS light source assembly 2 close to the base 3, and the metal-plated pad 7 is electrically connected to the end of the pin 32 through the metal wire 8; the heating layer 12 on the side of the double-sided silicon-based MEMS light source assembly 2 away from the base 3 is directly electrically connected to the end of the pin 32 through the metal wire 8.

[0029] In addition, the double-sided silicon-based MEMS light source component 2 can also be replaced by a double-sided silicon-based heating wire or a double-sided ceramic-based heating wire to achieve the application function of bidirectionally radiating infrared light to both ends based on the electrothermal principle.

[0030] Specifically, Figure 6As shown, the double-sided silicon-based MEMS light source assembly 2 includes a silicon substrate 11, two heating layers 12 and two infrared radiation material layers 21; the silicon substrate 11 is provided with a substrate through hole, the two heating layers 12 are respectively attached to the two sides of the silicon substrate 11, and the two infrared radiation material layers 21 are respectively attached to the outer side surfaces of the two heating layers 12; the heating layers 12 located at both ends of the substrate through hole and the attached infrared radiation material layers 21 are combined into an infrared radiation unit, the infrared radiation unit is suspended at the outer opening of the substrate through hole, and the heating layer 12 in the infrared radiation unit extends outward and forms a branch arm connected to the heating layer 12 at the outer edge of the substrate through hole. Wherein, the infrared radiation material layer 21 is nano-platinum black, nano-black silicon, carbon nanotubes, graphene or amorphous carbon film doped with metal elements, or a super surface material based on Au, Al2O3 or Au material, or a ZnNiP chemical plating layer.

[0031] A double-sided silicon-based MEMS light source assembly 2 may be provided, including a silicon substrate 11, two heating layers 12, and two infrared radiation material layers 21. The heating layers 12 located at the openings at both ends of the substrate through hole are attached to and combined with the infrared radiation material layers 21 to form an infrared radiation unit, that is, an infrared radiation unit is suspended at each of the openings at both ends of the substrate through hole, and the heating layer 12 in the infrared radiation unit is connected to the heating layer 12 at the outer edge of the substrate through hole through a support arm, and the support arm is formed by the heating layer 12 in the infrared radiation unit extending outward. The heating layers 12 on both sides of the silicon substrate 11 radiate infrared light respectively, and after enhanced radiation based on the enhanced radiation effect of the infrared radiation material layer 21, the infrared light source is radiated outward from both sides of the silicon substrate 11 to form a double-sided infrared light source. This double-sided silicon-based MEMS light source assembly 2 can effectively reduce the module volume of the NDIR gas sensor, and can simplify the control circuit of the infrared light source assembly to achieve multi-gas component detection. The cavity 101 penetrating the silicon substrate 11 from top to bottom is hourglass-shaped, and the cavity 101 is symmetrically arranged along a midline parallel to the heating layer 12; the cross section of the cavity 101 is formed by combining two symmetrical trapezoids, and the specific structure is as follows: Figure 6 shown.

[0032] Furthermore, the size of the openings at both ends of the cavity 101 can be set to be larger than the inner diameter of the tube core 31, and the size of the infrared radiation unit can be set to be smaller than the inner diameter of the tube core 31. The processing method of the double-sided silicon-based MEMS light source component 2 and the infrared radiation material layer 21 therein is not specifically limited in the present invention, and the size can be designed and processed according to actual needs.

[0033] In a more specific embodiment, the silicon substrate 11 is a single crystal silicon substrate 11 or an SOI silicon wafer substrate. Specifically, the heating layer 12 includes a stacked support layer, a heating electrode and an isolation layer; the heating electrode is a metal composite film layer made of one or more materials selected from Pt, Au, W, Al, tin nitride, nickel-chromium alloy, MoSi2, or a polycrystalline silicon film doped with B by ion implantation; the support layer and the isolation layer are a single layer of SiO2 or a single layer of Si3N4 or a single layer of SiN x , or a composite film layer composed of multiple film layers of SiO2 layer, Si3N4 layer and SiNx layer. Wherein, the inner and outer surfaces of the base are electroplated with a metal film layer, and the metal film layer is formed by electroplating one or more materials of Ni, Au, Al, and Pt.

[0034] The silicon substrate 11 is a single crystal silicon substrate 11 or an SOI silicon wafer substrate. The base 3 may be made of cold-rolled steel, stainless steel, or Kovar alloy, and the metal film layer electroplated on the inner and outer surfaces of the base 3 is formed by electroplating one or more materials of Ni, Au, Al, or Pt. The infrared detector 41 is a thermopile, a pyroelectric, or a bolometer. The cap 6 is made of cold-rolled steel, stainless steel, or Kovar alloy, and the inner and outer surfaces of the cap 6 may be electroplated to form a metal film layer, and the metal film layer is also formed by electroplating one or more materials of Ni, Au, Al, or Pt. The metal-plated pad 7 may be a silicon-based or ceramic-based pad with one or more metal film layers of Au, Pt, Ag, Al, or Cu evaporated on the surface.

[0035] like Figure 7 As shown, the positions corresponding to each through hole of the base 3 extend outward to form a hollow tube core 31, and the axes of the hollow tube core 31 are parallel. The inner and outer surfaces of the tube core 31 are electroplated with an infrared reflective metal film layer; the side wall of the tube core 31 is also provided with an air hole 33, and the outer side of the air hole 33 is covered with a waterproof breathable film or coated with a water vapor absorbing material, and the water vapor absorbing material can be quicklime or a highly absorbent resin. Specifically, the metal film layer electroplated on the surface of the tube core 31 is formed by electroplating one or more materials selected from Ni, Au, Al, and Pt, and the metal film layer can be extended and electroplated on the inner and outer surfaces of the base 3. The use of a hollow tube core 31 to replace the absorption chamber component in the NDIR gas sensor module effectively reduces the number of discrete components of the sensor, improves processing efficiency, and improves the stability and robustness of the system.

[0036] In the specific manufacturing process, such as Figure 1As shown, the silicon-based MEMS light source assembly 1 of the back-through structure can be solid-die bonded on the base 3 by silver paste. The setting position of the silicon-based MEMS light source assembly 1 corresponds to the opening of the through hole of the base 3. The metal wire 8 is used for wire bonding to realize the electrical connection between the silicon-based MEMS light source assembly 1 and the pin 32. An infrared reflective metal film layer can be set on the inner surface of the arc-shaped tube cap 6. The arc-shaped tube cap 6 is fixed to the base 3 by laser sealing welding or resistance welding to realize the packaging of the silicon-based MEMS light source assembly 1. In this process, an ordinary tube cap 6 without an infrared reflective metal film layer can also be used for packaging. A detection assembly 4 is set at one end of the tube core 31 away from the silicon-based MEMS light source assembly 1, thereby forming a miniature NDIR gas sensor. The silicon-based MEMS light source assembly 1 radiates infrared light outward from the cavity 101. The arc-shaped tube cap 6 ensures that the infrared light enters the tube core 31 to the greatest extent. The absorption of infrared light by the target gas entering the tube core 31 through the air hole 33 conforms to the Lambert-Beer law: Where I is the outgoing light intensity, I 0 is the incident light intensity, is the molar absorption coefficient, C is the gas concentration, L is the effective air chamber length, e is the natural logarithm base. Based on the above principle, the target gas concentration can be detected. By using the base 3 of the above absorption chamber integrated structure and combining it with the back-transparent silicon-based MEMS light source component 1, a NDIR gas sensor with simple structure, high stability and robustness is obtained, which effectively reduces the integration difficulty and the volume of the sensor, and improves the processing efficiency and consistency of the sensor.

[0037] In the manufacturing process of another structure of sensor, such as Figures 2 to 4As shown, the above-mentioned double-sided silicon-based MEMS light source component 2 can be solid-die-bonded on the base 3 by silver paste, and the setting position of the double-sided silicon-based MEMS light source component 2 corresponds to the opening of the through hole of the base 3. The metal wire 8 and the metal-plated pad 7 are used for wire bonding, so as to realize the electrical connection between the double-sided silicon-based MEMS light source component 2 and the pin 32. The tubular cap 6 with an infrared reflective metal film layer on the inner surface is fixed to the base 3 by laser sealing welding or resistance welding to realize the packaging of the double-sided silicon-based MEMS light source component 2. A detection component 4 is set at one end of the tube core 31 away from the double-sided silicon-based MEMS light source component 2, and a detection component 4 is set at each opening of the tubular cap 6 away from the double-sided silicon-based MEMS light source component 2, thereby forming a miniature NDIR mixed multi-gas component detection sensor. The detection principle of the obtained mixed multi-gas component detection sensor is the same as the above detection principle, except that the function is no longer to detect a single gas component, but to detect multiple different gas components simultaneously.

[0038] like Figure 2 and Figure 3 As shown, the base 3 with tube cores 31 of different lengths and the tubular tube caps 6 of different lengths can be designed and processed to create absorption chambers with different lengths of optical paths; Figure 3 The length of the middle tubular cap 6 is less than Figure 2 The length of the middle tubular cap 6 is Figure 3 The shorter length of the tubular cap 6 can detect high-concentration gas, and the longer length of the tube core 31 can be used to detect low-concentration gas, thus realizing a wide-range gas sensor based on NDIR. The detection technology principle is the same as above and will not be repeated here.

[0039] In order to cope with more complex infrared gas detection application scenarios, an array multi-channel setting structure can be adopted, such as Figure 4 As shown, a base 3 with multiple tube cores 31 can be provided, and multiple tubular channels can be provided on the end of the tubular cap 6 away from the double-sided silicon-based MEMS light source assembly 2, then the number of tubular channels on the tubular cap 6 can be equal to the number of tube cores 31 in the base 3; a detection assembly 4 is correspondingly provided at the end opening of the tubular channel, and multiple double-sided silicon-based MEMS light source assemblies 2 are used to realize multi-channel infrared gas detection. The principle of the detection technology is the same as above and will not be repeated here. Compared with the existing NDIR gas detection module, the present invention provides a design method with higher stability and robustness, smaller size, simple structure and high processing efficiency.

[0040] The embodiment of the present invention provides a gas sensor based on non-dispersive infrared detection, which includes a base 3, a tube cap 6, at least one detection component 4 and at least one infrared light source component; the tube cap 6 is covered on the base 3, and the outer edge of the tube cap 6 is fixedly connected to the base 3; the base 3 is provided with at least one base through hole penetrating the base 3; the side walls of each base through hole extend to the side away from the tube cap 6 to form a hollow tube core 31; each infrared light source component is covered and arranged in one end of a base through hole facing the tube cap 6, and the cavity 101 in the infrared light source component is connected to one base through hole; an air hole 33 is provided on the wall of each tube core 31; a pin 32 penetrates the base 3 and the end thereof extends into one side of the infrared light source component, and the heating layer 12 in the infrared light source component is electrically connected to the end of the pin 32 through a metal wire 8; each detection component 4 is assembled at one end of a corresponding tube core 31 away from the infrared light source component, and the end of the tube core 31 is sealed. The above-mentioned gas sensor is designed based on the integrated structure of the absorption gas chamber and the back-transmitted infrared light source assembly. No additional structure is required to fix the infrared light source, which makes the sensor structure simple and small in size, and effectively reduces the difficulty of manufacturing and integration of the sensor, greatly enhancing its stability and system robustness.

[0041] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A gas sensor based on non-dispersive infrared detection, characterized in that: The gas sensor comprises a base, a tube cap, at least one detection component and at least one infrared light source component; The tube cap is covered on the base, and the outer edge of the tube cap is fixedly connected to the base; the base is provided with at least one base through hole penetrating the base; the side wall of each base through hole extends to a side away from the tube cap to form a hollow tube core; Each of the infrared light source components is covered and arranged in one end of a through hole of the base facing the tube cap, and the cavity in the infrared light source component is connected with one through hole of the base; a vent hole is provided on the wall of each tube core; The pin passes through the base and the end thereof extends into one side of the infrared light source assembly, and the heating layer in the infrared light source assembly and the end of the pin are electrically connected via a metal wire; Each of the detection components is assembled at one end of a corresponding tube core away from the infrared light source component, and the end of the tube core is closed; each of the detection components is provided with at least one infrared detector, and each of the infrared detectors is provided with a narrow-band filter at one end facing the infrared light source component; the detection pins electrically connected to each of the infrared detectors extend from the inside of the detection component to the outside.

2. The gas sensor based on non-dispersive infrared detection according to claim 1, characterized in that: The infrared light source component is a silicon-based MEMS light source component, a heating metal foil or a metal wire; The silicon-based MEMS light source component is recessed inwardly on one side facing the base through hole to form the cavity. The tube cap is an arc-shaped tube cap with an opening on one side, and the opening of the arc-shaped tube cap faces the base.

3. The gas sensor based on non-dispersive infrared detection according to claim 2, characterized in that: The silicon-based MEMS light source assembly includes a silicon substrate, a heating layer and a reflective layer; The silicon substrate is provided with a substrate through hole, the heating layer is attached to a side of the silicon substrate away from the base and covers the substrate through hole to form an inwardly recessed cavity, and the reflective layer is attached to the upper layer of the heating layer.

4. The gas sensor based on non-dispersive infrared detection according to claim 3, characterized in that: The reflective layer is a metal reflective film made of one or more materials selected from Au, Pt, Ag, Al, and Cu.

5. The gas sensor based on non-dispersive infrared detection according to claim 1, characterized in that: The infrared light source component is a double-sided silicon-based MEMS light source component, a double-sided silicon-based heating wire or a double-sided ceramic-based heating wire; The double-sided silicon-based MEMS light source assembly is provided with a cavity running through from top to bottom; the tube cap is a tubular tube cap with openings at both ends; One or more openings are provided at one end of the tube cap away from the base, and each opening at the end of the tubular tube cap away from the base is provided with a detection assembly; A metal-plated pad is provided between the double-sided silicon-based MEMS light source assembly and the base. The metal-plated pad is electrically connected to the heating layer of the double-sided silicon-based MEMS light source assembly close to the base. The metal-plated pad is electrically connected to the end of the pin through a metal wire.

6. The gas sensor based on non-dispersive infrared detection according to claim 5, characterized in that: The double-sided silicon-based MEMS light source assembly includes a silicon substrate, two heating layers and two infrared radiation material layers; A substrate through hole is provided on the silicon substrate, the two heating layers are respectively bonded to the two sides of the silicon substrate, and the two infrared radiation material layers are respectively bonded to the outer side surfaces of the two heating layers; the heating layers located at the two ends of the substrate through hole and the bonded infrared radiation material layers are combined into an infrared radiation unit, and the infrared radiation unit is suspended at the outer opening of the substrate through hole, and the heating layer in the infrared radiation unit extends outward to form a support arm connected to the heating layer at the outer edge of the substrate through hole.

7. The gas sensor based on non-dispersive infrared detection according to claim 6, characterized in that: The infrared radiation material layer is nano-platinum black, nano-black silicon, carbon nanotubes, graphene or amorphous carbon film doped with metal elements, or a super surface material based on Au, Al2O3 or Au material, or a ZnNiP chemical plating layer.

8. The gas sensor based on non-dispersive infrared detection according to any one of claims 1 to 7, characterized in that: The silicon substrate is a single crystal silicon substrate or an SOI silicon wafer substrate.

9. The gas sensor based on non-dispersive infrared detection according to any one of claims 1 to 7, characterized in that: The heating layer comprises a stacked support layer, a heating electrode and an isolation layer; the heating electrode is a metal composite film layer made of one or more materials selected from Pt, Au, W, Al, tin nitride, nickel-chromium alloy, MoSi2, or a polysilicon film doped with B by ion implantation; The support layer and the isolation layer are single-layer SiO2 or single-layer Si3N4 or single-layer SiN x , or a composite film layer composed of multiple film layers including SiO2 layer, Si3N4 layer and SiNx layer.

10. The gas sensor based on non-dispersive infrared detection according to any one of claims 1 to 7, characterized in that: The inner and outer surfaces of the base are electroplated with metal film layers, and the metal film layers are formed by electroplating one or more materials selected from Ni, Au, Al, and Pt.

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