Gas sensor based on non-dispersive infrared detection

Abstract

The present invention discloses a gas sensor based on non-dispersive infrared detection. 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. At least one base through-hole penetrating the base is provided on the base. The side walls of each base through-hole extend towards the side away from the tube cap to form a hollow tube core. Each infrared light source component is covered and arranged at one end of a base through-hole facing the tube cap, and the cavity inside the infrared light source component is communicated with a base through-hole. Air-permeable holes are provided on the walls of each tube core. The pins penetrate the base and the ends extend into one side of the infrared light source component. Each detection component is assembled at one end of the tube core away from the infrared light source component and seals the end of the tube core. The above gas sensor is designed based on an absorption gas chamber integrated structure and a back-transmissive infrared light source component, reducing the integration difficulty and improving the robustness and stability of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, 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 exhalation diagnosis, smart agriculture, and gas monitoring in industrial processes. Most of the existing NDIR gas sensors are assembled into product modules through integration and encapsulation processes using split components, which pose great challenges in terms of product consistency and miniaturization, and further improvement is needed in terms of product stability and robustness. In addition, for some special application scenarios, such as wide-range gas monitoring or mixed multi-gas detection, there is still a lack of design solutions with high stability and robustness.

[0003] Generally, an NDIR gas sensor is composed of components such as an infrared light source, an absorption gas chamber, an infrared detector, and a circuit board. The reflector, infrared light source, and infrared detector are soldered on the circuit board and fixed at both ends of the absorption gas chamber, and sealed with adhesive for pasting and encapsulation. The overall structure and production process are complex, which is not conducive to mass production under the condition of ensuring high reliability. The design of the non-integrated structure has poor stability and robustness of the sensor, and the consistency and miniaturization are often not ideal, and further improvement is urgently needed. In addition, most of the existing NDIR gas sensors adopt a 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 the aspect of mixed multi-gas detection, it is generally composed of a single or multiple infrared light sources combined with a single or multiple infrared detectors, which has disadvantages such as complex structure, poor robustness, and large volume. Summary of the Invention

[0004] An 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 existing in the gas sensors in the prior art methods.

[0005] An 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;

[0006] The tube cap covers the base, and the outer edge of the tube cap is fixedly connected to the base; at least one base through hole penetrating the base is provided on the base; the side walls of each base through hole extend away from the tube cap to form a hollow tube core;

[0007] Each of the infrared light source components is covered and arranged at one end of a corresponding base through hole facing the tube cap, and the cavity inside the infrared light source component is communicated with one of the base through holes; air holes are provided on the walls of each of the die chips.

[0008] The lead pins penetrate through the base and the ends extend into one side of the infrared light source component, and the heating layer in the infrared light source component is electrically connected to the ends of the lead pins through metal wires.

[0009] Each of the detection components is assembled at one end of a corresponding die chip away from the infrared light source component and closes the end of the die chip; at least one infrared detector is provided in each of the detection components, and a narrowband filter is provided at one end of each of the infrared detectors facing the infrared light source component; the detection lead pins electrically connected to each of the infrared detectors extend from the inside of the detection component to the outside.

[0010] In the gas sensor based on non-dispersive infrared detection, the infrared light source component is a silicon-based MEMS light source component, a heating metal foil or a metal wire.

[0011] One side of the silicon-based MEMS light source component facing the base through hole is recessed inward 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.

[0012] In the gas sensor based on non-dispersive infrared detection, the silicon-based MEMS light source component mainly includes a silicon substrate, a heating layer and a reflective layer.

[0013] Substrate through holes are provided on the silicon substrate, the heating layer is attached to the side of the silicon substrate away from the base and covers the substrate through holes to form a recessed cavity inward, and the reflective layer is attached to the upper layer of the heating layer.

[0014] In the gas sensor based on non-dispersive infrared detection, the reflective layer is a metal reflective film prepared from one or more of the materials of Au, Pt, Ag, Al, and Cu.

[0015] In the gas sensor based on non-dispersive infrared detection, the infrared light source component is a double-sided silicon-based MEMS light source component, a double-sided silicon-based heating metal wire or a double-sided ceramic-based heating metal wire.

[0016] A cavity penetrating up and down is provided on the double-sided silicon-based MEMS light source component; the tube cap is a tubular tube cap with openings at both ends.

[0017] One or more openings are provided at the end of the tube cap away from the base, and each of the detection components is provided at each of the openings at the end of the tubular tube cap away from the base.

[0018] A metal plating pad is provided between the double-sided silicon-based MEMS light source assembly and the base. The metal plating pad electrically connects the heating layer on the side of the double-sided silicon-based MEMS light source assembly close to the base, and the metal plating pad is electrically connected to the end of the pin through a metal wire.

[0019] 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;

[0020] Substrate through-holes are provided on the silicon substrate. The two heating layers are respectively attached to both sides of the silicon substrate, and the two infrared radiation material layers are respectively attached to the outer sides of the two heating layers; the heating layer and the attached infrared radiation material layer at both ends of the substrate through-hole form an infrared radiation unit, and the infrared radiation unit is suspended at the outer opening of the substrate through-hole. The heating layer in the infrared radiation unit extends outward and forms a branch arm connected to the heating layer at the outer edge of the substrate through-hole.

[0021] 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 a metasurface material based on Au, Al 2 O 3 or Au material, or a ZnNiP chemical plating layer.

[0022] The gas sensor based on non-dispersive infrared detection, wherein the silicon substrate is a single-crystal silicon substrate or an SOI silicon wafer substrate.

[0023] The gas sensor based on non-dispersive infrared detection, wherein the heating layer includes a support layer, a heating electrode and an isolation layer stacked; the heating electrode is a metal composite film layer prepared from one or more of Pt, Au, W, Al, tin nitride, nickel-chromium alloy, MoSi 2 or a polysilicon thin film doped with ion-implanted B;

[0024] The support layer and the isolation layer are single-layer SiO 2 or single-layer Si 3 N 4 or single-layer SiN x or composed of multiple film layers of SiO 2 layer, Si 3 N 4 layer and SiNx layer to form a composite film layer.

[0025] The described gas sensor based on non-dispersive infrared detection, wherein a metal film layer is electroplated on the inner and outer surfaces of the base, and the metal film layer is formed by electroplating with one or more materials of Ni, Au, Al, and Pt.

[0026] An embodiment of the present invention provides a gas sensor based on non-dispersive infrared detection. 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; at least one base through hole penetrating the base is provided on the base; the side walls of each base through hole extend towards the side away from the tube cap to form a hollow tube core; each infrared light source component is covered and arranged at one end of a base through hole facing the tube cap, and the cavity in the infrared light source component is communicated with a base through hole; air permeable holes are provided on the walls of each tube core; the lead penetrates the base and the end extends into one side of the infrared light source component, and an electrical connection is made between the heating layer in the infrared light source component and the end of the lead through a metal wire; each detection component is assembled at one end of the corresponding tube core away from the infrared light source component and seals the end of the tube core. The above gas sensor is designed based on an absorption gas chamber integrated structure and a back-transmissive infrared light source component, without the need for an additional structure to fix the infrared light source, effectively reducing the integration difficulty and volume of the sensor, and greatly enhancing its stability and system robustness. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 It is a cross-sectional structure diagram of the gas sensor based on non-dispersive infrared detection provided by the embodiment of the present invention;

[0029] Figure 2 It is another cross-sectional structure diagram of the gas sensor based on non-dispersive infrared detection provided by the embodiment of the present invention;

[0030] Figure 3 It is yet another cross-sectional structure diagram of the gas sensor based on non-dispersive infrared detection provided by the embodiment of the present invention;

[0031] Figure 4 It is yet another cross-sectional structure diagram of the gas sensor based on non-dispersive infrared detection provided by the embodiment of the present invention;

[0032] Figure 5 It is a cross-sectional structure diagram of the infrared light source component provided by the embodiment of the present invention;

[0033] Figure 6 Another cross-sectional structure diagram of the infrared light source component provided by the embodiment of the present invention;

[0034] Figure 7 A three-dimensional structure diagram of the base provided by the embodiment of the present invention;

[0035] Reference numerals: 3, base; 6, 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, reflective layer; 21, infrared radiation material layer; 31, die; 32, pin; 33, vent hole; 41, infrared detector; 42, narrowband filter; 43, detection pin; 7, metal plating pad; 8, metal wire. Detailed implementation manners

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

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

[0038] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms. It should be further understood that the term " / and" used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the related listed items, and includes these combinations.

[0039] Please refer to Figures 1 to 2, as shown in the figure, an embodiment of the present application discloses a gas sensor based on non-dispersive infrared detection. Among them, 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; at least one base through hole penetrating the base 3 is provided on the base 3; the side walls of each base through hole extend away from the tube cap 6 to form a hollow tube core 31; each infrared light source component is covered and arranged at one end of a base through hole facing the tube cap 6, and the cavity 101 in the infrared light source component is communicated with a base through hole; air holes 33 are provided on the walls of each tube core 31; a lead 32 penetrates the base 3 and its end 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 lead 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 closes the end of the tube core 31; at least one infrared detector 41 is provided in each detection component 4, and a narrow-band filter 42 is provided at one end of each infrared detector 41 facing the infrared light source component; a detection lead 43 electrically connected to each infrared detector 41 extends from the inside of the detection component 4 to the outside.

[0040] The tube cap 6 is covered on the base 3. One or more base through holes can be provided on the base 3. The side walls of each base through hole extend away from the tube cap 6 to form a hollow tube core 31; the specific structure is as Figure 1 shown Figure 1 In the figure, one base through hole is provided on the base 3, and a tube core 31 is correspondingly extended. An infrared light source component is covered and arranged at one end of each base through hole facing the tube cap 6, as Figure 1 , Figure 2 and Figure 3 both show that an infrared light source component is covered and arranged at one end of a base through hole. Figure 4 In the figure, it shows that an infrared light source component is covered and arranged at one end of each of a plurality of base through holes respectively. A detection component 4 is assembled at one end of each tube core 31 away from the infrared light source component. The detection component 4 includes at least one infrared detector 41 and at least one narrow-band filter 42. As Figure 1 shown, two infrared detectors 41 and two narrow-band filters 42 are assembled in the detection component 4.

[0041] Specifically, a step can be provided at the edge of the base 3, and the outer edge of the pipe cap 6 can be embedded on the step, so as to realize the fixed connection between the pipe 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 component; the size of the base 3 can be designed and processed according to actual requirements, and the inner diameter and outer diameter of the chip 31 need to be determined corresponding to the size of the infrared light source component. The diameter of the metal wire 8 is 15 μm to 50 μm.

[0042] In a specific embodiment, the infrared light source component is a silicon-based MEMS light source component 1, a heating metal foil or a metal wire; the side of the silicon-based MEMS light source component 1 facing the through hole of the base is recessed inward to form the cavity 101, and the pipe cap 6 is an arc-shaped pipe cap 6 with one side open, and the opening of the arc-shaped pipe cap 6 faces the base 3. Specifically, as Figure 5 shown, the silicon-based MEMS light source component 1 mainly includes a silicon substrate 11, a heating layer 12 and a reflective layer 13; a substrate through hole is provided on the silicon substrate 11, 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 a recessed cavity 101 inward, and the reflective layer 13 is attached to the upper layer of the heating layer 12. Among them, the reflective layer 13 is a metal reflective film prepared from one or more of the materials of Au, Pt, Ag, Al, and Cu.

[0043] As Figure 1 shown, the pipe cap 6 is an arc-shaped pipe cap 6 with one side open, then only one detection component 4 is assembled at one end of one chip 31 away from the infrared light source component. The side of the silicon-based MEMS light source component 1 facing the through hole of the base is recessed inward to form a cavity 101, and the cavity 101 is communicated with the through hole of the base. 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 generates heat by electricity and radiates infrared light outward. 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 backside-through silicon-based MEMS infrared light source. Specifically, the cross section of the cavity 101 of the silicon substrate 11 can be set as a trapezoid or a rectangle, and the opening size of the cavity 101 can be set to be larger than the inner diameter of the chip 31. The setting structure of this backside-through silicon-based MEMS infrared light source can effectively reduce the difficulty of device integration and assembly.

[0044] 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 requirements. 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 based on the principle of electrothermal heating.

[0045] In another specific embodiment, the infrared light source assembly is a double-sided silicon-based MEMS light source assembly 2, a double-sided silicon-based heating wire, or a double-sided ceramic-based heating wire; a cavity 101 penetrating up and down is provided on the double-sided silicon-based MEMS light source assembly 2; the tube cap 6 is a tubular tube cap 6 with openings at both ends; one or more openings are provided at one end of the tube cap 6 away from the base 3, and a detection assembly 4 is provided at each opening at one end of the tubular tube cap 6 away from the base 3; a metal plating spacer 7 is provided between the double-sided silicon-based MEMS light source assembly 2 and the base 3, and the metal plating spacer 7 electrically connects 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 plating spacer 7 and the end of the pin 32 are electrically connected by a metal wire 8.

[0046] As Figures 2 to 4 shown, to further improve the ability to detect different gas components (such as simultaneously detecting nitric oxide gas and carbon dioxide gas), the infrared light source assembly can be configured as a double-sided silicon-based MEMS light source assembly 2. A cavity 101 penetrating up and down is provided on the double-sided silicon-based MEMS light source assembly 2, and the tube cap 6 is a tubular tube cap 6 with openings at both ends. One opening can be provided at one end of the tube cap 6 away from the base 3, and the structure is as Figure 2 and Figure 3 shown; multiple openings can be provided at one end of the tube cap 6 away from the base 3, and the structure is as Figure 4 shown. A detection assembly 4 is provided at each opening at one end of the tubular tube cap 6 away from the base 3. The metal plating spacer 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 plating spacer 7 and the end of the pin 32 are electrically connected by a metal wire 8; then 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.

[0047] In addition, the double-sided silicon-based MEMS light source assembly 2 can also be replaced with a double-sided silicon-based heating wire or a double-sided ceramic-based heating wire to realize the application function of radiating infrared light bidirectionally to both ends based on the electrothermal principle.

[0048] Specifically, as Figure 6As shown, the double-sided silicon-based MEMS light source component 2 includes a silicon substrate 11, two heating layers 12, and two infrared radiation material layers 21; a substrate through-hole is provided on the silicon substrate 11, and the two heating layers 12 are respectively attached to both sides of the silicon substrate 11, and the two infrared radiation material layers 21 are respectively attached to the outer sides of the two heating layers 12; the heating layer 12 at both ends of the substrate through-hole and the attached infrared radiation material layer 21 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 12 in the infrared radiation unit extends outward and forms an arm connected to the heating layer 12 at the outer edge of the substrate through-hole. Among them, the infrared radiation material layer 21 is nano platinum black, nano black silicon, carbon nanotubes, graphene, or an amorphous carbon film doped with metal elements, or a metasurface material based on Au, Al 2 O 3 or an Au material, or a ZnNiP chemical plating layer.

[0049] It can be set that the double-sided silicon-based MEMS light source component 2 includes a silicon substrate 11, two heating layers 12, and two infrared radiation material layers 21. Then, the heating layer 12 and the infrared radiation material layer 21 at both ends of the substrate through-hole are attached and combined into an infrared radiation unit, that is, an infrared radiation unit is respectively suspended at both ends of the substrate through-hole. 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 an arm, and the 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 respectively radiate infrared light. After being enhanced by the enhanced radiation effect of the infrared radiation material layer 21, it radiates outward from both sides of the silicon substrate 11 to form an infrared light source with a double-sided radiation function. This double-sided silicon-based MEMS light source component 2 can effectively reduce the module volume of the NDIR gas sensor, and can simplify the control circuit of the infrared light source component to realize the detection of multiple gas components. The vertically penetrating cavity 101 in the silicon substrate 11 is hourglass-shaped, and the cavity 101 is symmetrically arranged along the midline parallel to the heating layer 12; the cross-section of the cavity 101 is formed by combining two symmetric trapezoids, and the specific structure is as Figure 6 shown.

[0050] Furthermore, it can be set that the sizes of the openings at both ends of the cavity 101 are larger than the inner diameter of the die 31, and the size of the infrared radiation unit is smaller than the inner diameter of the die 31. The processing methods of the double-sided silicon-based MEMS light source component 2 and the infrared radiation material layer 21 therein are not specifically limited in the present invention, and the sizes can be designed and processed according to actual needs.

[0051] In a more specific embodiment, the silicon substrate 11 is a single-crystalline silicon substrate 11 or a SOI silicon wafer substrate. Specifically, the heating layer 12 includes a support layer, a heating electrode, and an isolation layer which are stacked; the heating electrode is a metal composite film layer prepared from one or more of the materials such as Pt, Au, W, Al, tin nitride, nickel-chromium alloy, and MoSi, or a polysilicon thin film doped with B by ion implantation; the support layer and the isolation layer are a single-layer SiO 2 or a single-layer Si 2 or a single-layer Si 3 N 4 or a single-layer SiN x , or a composite film layer composed of multiple film layers such as SiO 2 layer, Si 3 N 4 layer and SiNx layer. Among them, the inner and outer surfaces of the base are electroplated with a metal film layer, and the metal film layer is formed by electroplating with one or more of the materials such as Ni, Au, Al, and Pt.

[0052] The silicon substrate 11 is a single-crystalline silicon substrate 11 or a SOI silicon wafer substrate. The material of the base 3 can be one of cold-rolled steel, stainless steel, and kovar alloy. The metal film layer electroplated on the inner and outer surfaces of the base 3 is formed by electroplating with one or more of the materials such as Ni, Au, Al, and Pt. The infrared detector 41 is one of a thermopile, a pyroelectric, and a bolometer. The material of the tube cap 6 is one of cold-rolled steel, stainless steel, and kovar alloy. The inner and outer surfaces of the tube cap 6 can be electroplated to form a metal film layer, and the metal film layer is also formed by electroplating with one or more of the materials such as Ni, Au, Al, and Pt. The metal-coated spacer 7 can be a silicon-based or ceramic-based spacer with a metal film layer of one or more of Au, Pt, Ag, Al, and Cu vapor-deposited on its surface.

[0053] As Figure 7 shown, at the position corresponding to each base through-hole on the base 3, a hollow tube core 31 extends outward. The axes of the hollow tube cores 31 are parallel, and the inner and outer surfaces of the tube core 31 are electroplated with a metal film layer for infrared reflection; the side wall of the tube core 31 is also provided with ventilation holes 33, and a waterproof and breathable membrane or a water vapor absorption material is covered at the outer side surface position of the ventilation holes 33. The water vapor absorption material can be quicklime or a superabsorbent resin. Specifically, the metal film layer electroplated on the surface of the tube core 31 is formed by electroplating with one or more of the materials such as 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. Using the hollow-structured tube core 31 to replace the absorption gas chamber assembly in the NDIR gas sensor module effectively reduces the number of discrete components of the sensor, improves the processing efficiency, and the stability and robustness of the system.

[0054] During the specific manufacturing process, as Figure 1As shown, the silicon-based MEMS light source component 1 with the above-mentioned backlight structure can be die-bonded on the base 3 with silver paste. The setting position of the silicon-based MEMS light source component 1 corresponds to the opening of the through-hole of the base 3. Wire bonding is performed with the metal wire 8 to realize the electrical connection between the silicon-based MEMS light source component 1 and the pin 32. An infrared reflective metal film layer can be provided on the inner surface of the arc-shaped cap 6. The arc-shaped cap 6 is fixed to the base 3 by laser welding or resistance welding to encapsulate the silicon-based MEMS light source component 1. In this process, an ordinary cap 6 without an infrared reflective metal film layer can also be used for encapsulation. A detection component 4 is provided at one end of the die 31 away from the silicon-based MEMS light source component 1, thus forming a micro NDIR gas sensor. The silicon-based MEMS light source component 1 radiates infrared light outward from the cavity 101. The arc-shaped cap 6 maximally ensures that the infrared light enters the die 31. The absorption of the infrared light by the target gas entering the die 31 through the air vent 33 conforms to the Lambert-Beer law: . In the formula I is the intensity of the outgoing light, I 0 is the intensity of the incident light, is the molar absorption coefficient, C is the gas concentration, L is the effective gas chamber length, e is the base of the natural logarithm. Based on the above principle, the concentration of the target gas can be detected. By using the base 3 with the above-mentioned absorption gas chamber integrated structure and combining it with the backlight type silicon-based MEMS light source component 1, a simple-structured, highly stable and robust NDIR gas sensor is obtained, effectively reducing the integration difficulty and the volume of the sensor, and improving the processing efficiency and the consistency of the sensor.

[0055] In the manufacturing process of a sensor with another structure, such as Figures 2 to 4As shown, the above-mentioned double-sided silicon-based MEMS light source component 2 can be fixed on the base 3 by silver paste die bonding. 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. Wire bonding is carried out using the metal wire 8 and the metal plating pad 7, 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 its inner surface is fixed to the base 3 by laser welding or resistance welding and the double-sided silicon-based MEMS light source component 2 is encapsulated. A detection component 4 is arranged at one end of the die 31 away from the double-sided silicon-based MEMS light source component 2, and a detection component 4 is arranged at each opening of the tubular cap 6 away from the double-sided silicon-based MEMS light source component 2, thus forming a micro NDIR hybrid multi-gas component detection sensor. The detection principle of the obtained hybrid multi-gas component detection sensor is the same as the above detection principle, except that the function realized is no longer to detect a single gas component, but to be able to detect multiple different gas components simultaneously.

[0056] As Figure 2 and Figure 3 shown, the base 3 with different lengths of dies 31 and the tubular caps 6 with different lengths can be designed and processed, so as to create absorption gas chambers with different optical path lengths; as Figure 3 in the tubular cap 6 has a length less than Figure 2 in the tubular cap 6 has a length, then Figure 3 the shorter-length tubular cap 6 in can detect high-concentration gases, and the longer-length die 31 can be used to detect low-concentration gases, realizing a wide-range gas sensor based on NDIR. The detection technical principle is the same as above and will not be elaborated here.

[0057] In order to cope with more complex infrared gas detection application scenarios, an array multi-channel setting structure can be adopted. As Figure 4 shown, a base 3 with multiple dies 31 can be set, and multiple tubular channels are arranged at one end of the tubular cap 6 away from the double-sided silicon-based MEMS light source component 2. Then the number of tubular channels on the tubular cap 6 can be equal to the number of dies 31 in the base 3; a detection component 4 is correspondingly arranged at the end opening of the tubular channel, and multiple double-sided silicon-based MEMS light source components 2 are used to realize multi-channel infrared gas detection. The detection technical principle is the same as above and will not be elaborated here. Compared with the existing NDIR gas detection module, the present invention provides a design method with higher stability and robustness, smaller volume, simple structure and high processing efficiency.

[0058] An embodiment of the present invention provides a gas sensor based on non-dispersive infrared detection. 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. At least one base through hole penetrating the base 3 is provided on the base 3. The side walls of each base through hole extend away from the tube cap 6 to form a hollow tube core 31. Each infrared light source component is covered and arranged at one end of a base through hole facing the tube cap 6, and the cavity 101 in the infrared light source component is communicated with a base through hole. Air holes 33 are provided on the walls of each tube core 31. A lead 32 penetrates the base 3 and its end extends into one side of the infrared light source component. The heating layer 12 in the infrared light source component is electrically connected to the end of the lead 32 through a metal wire 8. Each detection component 4 is assembled at one end of the corresponding tube core 31 away from the infrared light source component and closes the end of the tube core 31. The above gas sensor is designed based on an absorption gas chamber integrated structure and a back-transmissive infrared light source component, without the need for an additional structure to fix the infrared light source, making the sensor simple in structure, small in size, effectively reducing the manufacturing and integration difficulty of the sensor, and greatly enhancing its stability and system robustness.

[0059] As described above, the above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to 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 a plurality of base through holes 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 sealed; 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; The tube cap is fixed to the base by laser sealing welding or resistance welding to achieve packaging of the infrared light source assembly; The tube cap comprises a tubular tube cap with openings at both ends; an opening is provided at a position corresponding to the through hole of the base at one end of the tube cap away from the base; the length of the absorption chamber formed by the tube core is not equal to the length of the absorption chamber formed by the tube cap; 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 component is provided with a cavity penetrating from top to bottom; A detection assembly is provided at each opening of the tubular cap away from one end of the base.

2. The gas sensor based on non-dispersive infrared detection according to claim 1, characterized in that: 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.

3. The gas sensor based on non-dispersive infrared detection according to claim 2, 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 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.

4. The gas sensor based on non-dispersive infrared detection according to claim 3, 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.

5. The gas sensor based on non-dispersive infrared detection according to any one of claims 3 to 4, characterized in that: The silicon substrate is a single crystal silicon substrate or an SOI silicon wafer substrate.

6. The gas sensor based on non-dispersive infrared detection according to any one of claims 1 to 4, 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.

7. The gas sensor based on non-dispersive infrared detection according to any one of claims 1 to 4, 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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