CN115236021A - Parallel double-channel infrared gas sensor - Google Patents

Abstract

The invention relates to a parallel dual-channel infrared gas sensor, comprising a reflector, a support plate, a base and an ASIC chip stacked in sequence from top to bottom; a reflector cavity and a plurality of ventilation holes are arranged on the reflector; The first through hole and the second through hole are respectively embedded with a first filter and two second filters; the top surface of the base is provided with an infrared light source and two infrared detectors, and the infrared light source is located in the first filter. Directly below the light sheet, two infrared detectors are respectively located directly below the two second filters, and the two infrared detectors are arranged side by side relative to the infrared light source; the infrared light source and the two infrared detectors are electrically connected to the ASIC chip. In the parallel dual-channel infrared gas sensor of the present invention, the reflector, the support plate, the base and the ASIC chip are stacked and arranged to reduce the volume; the reflection cavity is a folded reflection structure, which increases the optical path; the infrared light source and the two infrared detectors are distributed At both ends of the base, the influence of the infrared light source on the thermal element can be isolated.

Description

A parallel dual-channel infrared gas sensor

technical field

The invention relates to the technical field of gas sensors, and more particularly to a parallel dual-channel infrared gas sensor.

Background technique

With the advancement of science and technology and the development of economy, the current society is gradually entering the era of Internet of Things, more and more sensing nodes are deployed, and the demand for sensors is increasing. The advantages of good health and non-toxicity have received extensive attention and research.

Infrared gas sensor is a miniature spectral analysis device, which can detect the concentration of gas by detecting the characteristic spectral absorption strength of gas molecules. Compared with other types of gas sensors such as electrochemical, catalytic combustion, semiconductor, etc., it has a wide range of applications, long service life, high sensitivity, good stability, less environmental interference, no poisoning, independent of oxygen, suitable for It has a series of advantages such as more gas, high cost performance, low maintenance cost, and online analysis. It is widely used in petrochemical, metallurgical industry, industrial and mining, air pollution detection, agriculture, medical and health and other fields.

Existing infrared sensors mostly use heating wires or incandescent lamps as infrared light sources, and TO packaged detectors as sensitive elements, which can detect gas components through signal detection and processing. Its large size is difficult to meet the needs of miniaturized gas sensors in some specific occasions. .

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a parallel dual-channel infrared gas sensor to solve the technical problem that the existing infrared gas sensor is too large.

The invention provides a parallel dual-channel infrared gas sensor, comprising a reflector, a support plate, a base and an ASIC chip stacked in sequence from top to bottom;

The reflector is provided with a reflection cavity and a plurality of ventilation holes communicating with the reflection cavity;

The support plate is provided with a first through hole and a second through hole, a first filter is embedded in the first through hole, and two second filters are embedded in the second through hole;

The top surface of the base is provided with an infrared light source and two infrared detectors, the infrared light source is located in the first through hole and directly below the first filter, and the two infrared detectors are located in the second through hole. in the hole and respectively located directly below the two second filters, and two infrared detectors are arranged side by side relative to the infrared light source;

The infrared light source and two infrared detectors are electrically connected to the ASIC chip.

Further, the inner wall of the reflection cavity includes a first main reflection surface, two second main reflection surfaces and a first auxiliary reflection surface, the top surface of the support plate is formed as a second auxiliary reflection surface, and the first auxiliary reflection surface is formed. The surface and the second auxiliary reflection surface are parallel to each other, the first main reflection surface is located directly above the first filter, and the two second main reflection surfaces are respectively located directly above the second filter.

Further, the first main reflection surface and the two second main reflection surfaces are both compound paraboloids, and the cross section of at least a part of the optical path between the first main reflection surface and the two second main reflection surfaces is the same as that of the base. The surface is vertical.

Further, the inner wall of the reflective cavity and the top surface of the support plate are both coated with gold film, silver and silver compound film or Bragg reflection film; and/or,

The material of the reflector and the support plate is aluminum, copper, plastic, resin, ABS material, silicon or glass; and/or,

The base is a PCB and is made of FR-4 material or ceramic material, and the infrared light source and the two infrared detectors are routed at two ends of the PCB.

Further, the ventilation holes are arranged on the top of the reflector or symmetrically distributed on both sides of the reflector, and the ventilation holes are covered with a waterproof and breathable film.

Further, the infrared light source is a MEMS light source or an LED light source, and the first filter is a bandpass filter or an M-I-M superstructure.

Further, the infrared detector is a pyroelectric detector chip or a photoelectric detector chip, and the second filter is a narrow-band filter or an M-I-M superstructure.

Further, one of the two second filters is set to allow the infrared light of the first wavelength band to pass, and the other is set to allow the infrared light of the second wavelength band to pass through, and the infrared light of the first wavelength band and the gas to be measured absorb the spectrum. Likewise, the infrared light in the second wavelength band cannot be absorbed by the gas to be measured.

9. The parallel dual-channel infrared gas sensor according to claim 1, wherein the base or the ASIC chip is provided with a thermistor.

Further, the ASIC chip integrates a power supply module, an analog signal processing module and a digital signal processing module, and the power supply module is the infrared light source, the thermistor, the infrared detector, and the analog signal processing module. and power supply to the digital signal processing module.

The parallel dual-channel infrared gas sensor of the present invention is packaged together with the reflector, the support plate, the base and the ASIC chip, thereby achieving the effect of reducing the volume and realizing the miniaturization and integration of the infrared gas sensor; symmetrical ventilation on both sides The hole enables the infrared gas sensor to be directly integrated into the airway of the gas analysis equipment, which is easy to use and responds quickly; the use of two parallel infrared detectors can correct the problem of signal drift caused by the aging of components and the contamination inside the reflection cavity. , and the coupling efficiency is high, and the concentrating effect is good.

Description of drawings

1 is a schematic structural diagram of a parallel dual-channel infrared gas sensor according to an embodiment of the present invention, wherein a reflector and a support plate are half-section views;

2 is an exploded view of a parallel dual-channel infrared gas sensor according to an embodiment of the present invention;

3 is a schematic structural diagram of a reflector of a parallel dual-channel infrared gas sensor according to an embodiment of the present invention, wherein the ventilation holes are symmetrically arranged on both sides of the reflector;

4 is a schematic structural diagram of a reflector of a parallel dual-channel infrared gas sensor according to another embodiment of the present invention, wherein a ventilation hole is provided on the top of the reflector;

5 is a top view of a support plate of a parallel dual-channel infrared gas sensor according to an embodiment of the present invention;

6 is a top view of a base of a parallel dual-channel infrared gas sensor according to an embodiment of the present invention;

7 is a schematic diagram of an optical path of a parallel dual-channel infrared gas sensor according to an embodiment of the present invention;

FIG. 8 is a ray tracing simulation result diagram of a parallel dual-channel infrared gas sensor according to an embodiment of the present invention;

FIG. 9 is a surface irradiance distribution diagram of two infrared detectors of a parallel dual-channel infrared gas sensor according to an embodiment of the present invention;

10 is a schematic diagram of the internal structure of an ASIC chip of a parallel dual-channel infrared gas sensor according to an embodiment of the present invention;

FIG. 11 is a graph showing the performance test result of the parallel dual-channel infrared gas sensor according to the embodiment of the present invention.

Detailed ways

Below in conjunction with the accompanying drawings, preferred embodiments of the present invention are given and described in detail.

Reference herein to "one embodiment" or "an embodiment" refers to a particular feature, structure, or characteristic that may be included in at least one implementation of the present application. In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the purpose of It is convenient to describe the application and to simplify the description, rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the application. In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first" or "second" may expressly or implicitly include one or more of that feature. Also, the terms "first," "second," etc. are used to distinguish between similar objects, and are not necessarily used to describe a particular order or precedence. It is to be understood that data so used may be interchanged under appropriate circumstances so that the embodiments of the application described herein can be practiced in sequences other than those illustrated or described herein.

As shown in FIG. 1 and FIG. 2, an embodiment of the present invention provides a parallel dual-channel infrared gas sensor, including a reflector 1, a support plate 2, a base 3 and an ASIC chip 4 stacked in sequence from top to bottom, as shown in FIG. As shown in FIG. 3, the reflector 1 has a reflection cavity 16, and two sides of the reflector 1 are symmetrically provided with a plurality of ventilation holes 5 communicating with the reflection cavity 16. In another embodiment, as shown in FIG. 4, the ventilation holes 5 can also be provided On the top of the reflector 1, the ventilation hole 5 is covered with a waterproof and breathable film 11. As shown in FIG. 5, the support plate 2 is provided with a first through hole 21 and a second through hole 22 opposite to each other, and the first through hole 21 is embedded A first filter 6 is provided, and two second filters 7 are embedded in the second through hole 22; the reflector 1 and the support plate 2 form an optical air chamber; as shown in FIG. 6, the top surface of the base 3 An infrared light source 8 and two infrared detectors 9 are provided. The infrared light source 8 is located in the first through hole 21 and is located directly below the first optical filter 6, and the two infrared detectors 9 are located in the second through hole 22 and are respectively located in two Right below the second filter 7, two infrared detectors 9 are arranged side by side with respect to the infrared light source 8, that is, the distances between the two infrared detectors 9 and the infrared light source 8 are the same; the ASIC chip 4 is used to provide signal processing functions, which are The infrared light source 8 is electrically connected to the infrared detector 9; when measuring the gas concentration, the gas enters the reflection cavity 16 from the ventilation hole 5, the ASIC chip 4 controls the infrared light source 8 to emit light periodically, and after the infrared light passes through the first filter 6 Entering the reflection cavity 16, after being reflected in the reflection cavity 16, it reaches the infrared detector 9 through the second filter 7, and the infrared detector 9 converts the received infrared light into an electrical signal and transmits it to the ASIC chip 4. After the ASIC chip 4 The gas concentration can be obtained after treatment.

In the present embodiment, the reflector 1 and the support plate 2 and the support plate 2 and the base 3 can be connected by sealant. In this way, after the connection, the reflector cavity 16 communicates with the outside world only through the ventilation hole 5, so that the measurement The results are more accurate.

It should be understood that other ways can also be used to achieve sealed connection between the reflector 1 and the support plate 2 and between the support plate 2 and the base 3, for example, a sealing ring is provided between the two, and then through screws, snaps, pins It is not limited in the present invention.

The base 3 and the ASIC chip 4 can be electrically connected by flip-chip bonding process or conductive glue, so that the ASIC chip 4 is electrically connected with the infrared light source 8 and the infrared detector 9 on the base 3 .

As shown in FIG. 3 and FIG. 7 , the inner wall of the reflection cavity 16 of the reflector 1 includes a first main reflection surface 12 , two second main reflection surfaces 13 and a first auxiliary reflection surface 14 , and the top surface of the support plate 2 is formed as a first main reflection surface 12 . Two auxiliary reflection surfaces 15, the first auxiliary reflection surface 14 and the second auxiliary reflection surface 15 are parallel to each other, the first main reflection surface 12 and the two second main reflection surfaces 13 are arranged opposite to each other, and the first main reflection surface 12 is located in the first filter The two second main reflection surfaces 13 are located directly above the two second filters 7 respectively.

The transmission process of the light in the reflection cavity 16 is folded reflection, that is, it is transmitted to the two infrared detectors 9 after multiple reflections. Specifically, the infrared light emitted by the infrared light source 8 can be collected by the first main reflection surface 12 after entering the reflection cavity 16 through the first filter 6. The first main reflection surface 12 has the function of collimating light, which will collect the collected Most of the infrared light is reflected as infrared light parallel to the first auxiliary reflecting surface 14, the reflected infrared light is uniformly transmitted to the two second main reflecting surfaces 13 in a V-shape, and the remaining few infrared light can pass through the first auxiliary reflecting surface 14 and the second main reflecting surface 13. The second auxiliary reflection surface 15 reflects and transmits it to the two second main reflection surfaces 13. The two second main reflection surfaces 13 have the function of focusing light, which can reflect the received infrared light and then focus it through the two second filters 7 respectively. At the center of the surfaces of the two infrared detectors 9 . The cross section of at least a part of the optical path between the first main reflection surface 12 and the two second main reflection surfaces 13 can be set to be perpendicular to the surface of the base to reduce the number of reflections, thereby reducing the loss of infrared light. Due to this folded reflection design, the optical path is increased, which is conducive to the full absorption of the gas molecules to be measured, and increases the attenuation of the infrared light reaching the infrared detector, thereby improving the sensitivity.

In this embodiment, the first main reflection surface 12 and the two second main reflection surfaces 13 are both compound paraboloids. The above-mentioned reflection function can be realized by setting the parameters of the paraboloids. The parameters are set as common knowledge in the field of optics. Compound parabolic concentrator, which will not be repeated here.

It should be noted that the first main reflection surface 12 and the two second main reflection surfaces 13 can also be set as planes, spherical surfaces, ellipsoid surfaces or other types of curved surfaces. An incident angle and a reflection angle between ° and 60° are sufficient.

In order to reduce the transmission loss of infrared light in the reflection cavity 16, the inner wall of the reflection cavity 16 and the top surface of the support plate 2 are coated with but not limited to gold film, silver and its compound film or Bragg reflection film.

As shown in FIG. 8, it can be proved by simulation that the reflective cavity 16 of the present invention can collect and collimate the infrared light emitted by the infrared light source 8, and the light is parallel to the base 3 to the two infrared detectors 9 ends in a V-shaped dispersion transmission, The second main reflecting surface 13 can collect the transmitted infrared light and focus it on the surface of the infrared detector 9; in conjunction with the light transmission process in FIG. 7 , FIG. 9 is a surface irradiance distribution diagram of two infrared detectors in the embodiment of the present invention , it can be known from the brightness and the maximum value of the scale in the figure that the present invention can improve the coupling efficiency and obtain a large irradiance on the surfaces of the two infrared detectors 9 .

The infrared light source 8 can be selected but not limited to a MEMS light source or an LED light source, which can radiate broad-spectrum infrared light, and the first optical filter 6 is a bandpass filter; the first optical filter 6 can also be replaced with an M-I-M superstructure (ie The metal antenna-dielectric layer-metal backplane three-layer structure) is directly fabricated on the surface of the infrared light source 8 to achieve corresponding narrow-band infrared light emission. For example, in this embodiment, the infrared light source 8 is set as a MEMS light source, which is realized by a MEMS processing technology, and is connected to the base 3 by a wire bonding method, and can emit broad-spectrum infrared light.

The infrared detector 9 can be selected from but not limited to pyroelectric detector chips or photoelectric detector chips. The two second filters 7 are both narrowband filters. The second optical filter 7 can also be replaced by an M-I-M superstructure, which is directly fabricated on the surface of the infrared detector 9 to realize corresponding narrow-band infrared light detection. For example, in this embodiment, the infrared detector 9 is a pyroelectric detector chip, which is realized by a MEMS processing technology, and is connected to the base 3 by a wire bonding method.

One of the two second filters 7 is set to allow the infrared light of the first wavelength band to pass, the other is set to allow the infrared light of the second wavelength band to pass, and the infrared light of the first wavelength band is set to be the same as the absorption spectrum of the gas to be measured, It can be absorbed by the gas to be measured, and the infrared light of the second band is set so that it cannot be absorbed by the gas to be measured, so that one of the two infrared detectors 9 is used to detect the infrared light signal that can be absorbed by the gas to be measured, and the other is used to detect the infrared light signal that can be absorbed by the gas to be measured. One is used to detect the infrared light signal that is not absorbed by the gas to be tested, and the infrared detector 9 that detects the first band is used as the reference signal, and the other is used as the reference signal. By comparing the two reference signals with the reference signal (for example, using differential , ratio, normalization and other arithmetic methods), the reference signal can be compensated, the result obtained is more accurate, and the signal drift problem caused by the aging of the components and the contamination inside the reflective cavity 16 can be corrected. For example, taking the detection of carbon dioxide gas as an example, since both carbon dioxide and water molecules absorb infrared light in the same spectrum (ie, the first band) of carbon dioxide, when only one infrared detector is set, it is impossible to determine how much infrared light is absorbed by carbon dioxide. , how much is absorbed by water molecules, and in the present invention, by setting two infrared detectors, the reference signal can collect the variation of the infrared light in the first band, and the reference signal can collect the infrared light in the second band Since carbon dioxide cannot absorb the infrared light in the second band, the change in the infrared light in the second band is the amount absorbed by the water molecules, and the change in the infrared light in the first band is the difference between the infrared light in the second band and the infrared light in the second band. After the change is normalized, it is the amount of infrared light absorbed by carbon dioxide, from which the concentration of carbon dioxide can be obtained.

Different gases have different absorption spectra due to their differences in molecular structure, concentration and energy distribution. Therefore, the specific values of the first and second bands can be modified as needed to detect the concentration of different gases to be tested, that is, , when the first waveband is set as the absorption spectrum of carbon dioxide, the gas sensor can detect the concentration of carbon dioxide, and when the first waveband is set as the absorption spectrum of nitrogen, the gas sensor can detect the concentration of nitrogen.

The first filter 6 is set to allow the infrared light of the wavelength band corresponding to the two second filters 7 to pass through, that is, the wavelength range of the infrared light allowed to pass by the first filter 6 is the combination of the first wavelength band and the second wavelength band. For example, in the application of detecting CO ₂ gas, if the first wavelength band is 4.2-4.3 μm and the second wavelength band is 3.9-4.0 μm, then the wavelength range of infrared light allowed by the first filter 6 is at least 3.9-4.3 μm .

2 and 6, the base 3 can also be provided with a thermistor 10, which is located near the two infrared detectors 9 for providing an ambient temperature correction coefficient to ensure that the gas sensor of the present invention can be used at various temperatures In normal operation, quantitative gas detection is realized, and the thermistor 10 is also electrically connected to the ASIC chip through the base 3 . Of course, the thermistor 10 can also be directly formed on the ASIC chip. The thermistor 10 can be selected from but not limited to semiconductor or ceramic materials.

In this embodiment, the thermistor 10 is made of ceramic material, which is integrated between the two infrared detectors 9 of the base 3 , and the resistance is selected but not limited to 100KΩ.

The materials of the reflector 1 and the support plate 2 can be selected but not limited to aluminum, copper and other metal materials, which can be realized by micromachining; 3D printing technology; or select but not limited to silicon or glass materials, using MEMS processing technology. In this embodiment, the reflector 1 and the support plate 2 are made of copper and are fabricated by micromachining.

The base 3 can be a printed circuit board (PCB), which is made of FR-4 or ceramic material. On the PCB, the infrared light source 8 and the two infrared detectors 9 are routed at both ends, and the infrared light source is isolated as the main heating element for the two. The influence of the infrared detector 9 and the thermistor 10 of the three thermally sensitive elements (the thermal conductivity in the direction with the electrical connection line is 80W/(mK), and the thermal conductivity in the direction without the electrical connection line is 0.3W/(mK)). In some feasible embodiments, the base 3 can also be an aluminum base, a copper base, or the like.

As shown in FIG. 10 , the ASIC chip 4 integrates a power supply module 41 , an analog signal processing module 42 and a digital signal processing module 43 . The power module 41 can respectively provide but not limited to 2.8V, 3V, 3.3V, 4V, 4.5V or 5V for the infrared light source 8, the infrared detector 9, the thermistor 10, the analog signal processing module 42 and the digital signal processing module 43 . The analog signal processing module 42 can process no less than two channels of analog signals, can realize but is not limited to a band-pass filtering function of 0.2-2 Hz, and can realize an adjustable gain in the range of 1-10,000 times. The analog signal processing module 42 can realize the functions of signal acquisition, signal amplification, and signal filtering. The digital signal processing module 43 can be, but is not limited to, an FPGA chip or an ARM core chip. The digital signal processing module 43 has a storage function and can have, but is not limited to, an internal storage space of 1M, 2M or 4M; the digital signal processing module 43 has a modulus Conversion capability, with more than two ADC sampling channels, the number of sampling bits can be but not limited to 12-bit, 16-bit, 18-bit or higher; the digital signal processing module 43 has logic control and communication functions, and can control the infrared light source 8 The switch and the realization of basic logic operations can send the signal after the operation to the external device, and can accept or store the instructions or data sent by the external device.

In the present invention, the reflector 1, the support plate 2, the base 3 and the ASIC chip are stacked and arranged, so that the infrared light source 8, the infrared detector 9 and the optical air chamber are packaged together, which can achieve the effect of reducing the volume. The length of the gas sensor is less than 15mm, the width is less than 13mm, the height is less than 7mm, or the total volume is less than 1500mm ³ , which realizes the miniaturization and integration of the infrared gas sensor.

The working principle of the parallel dual-channel infrared gas sensor of the present embodiment (the infrared light source is a MEMS light source, and the infrared detector is a pyroelectric detector) will be introduced below:

After power-on, the ASIC chip controls the infrared light source to periodically turn on the light. When there is no gas to be measured, the divergent infrared light emitted by the infrared light source 8 passes through the first filter 6 and becomes infrared light including the first band and the second band. They are collected by the first main reflection surface 12 and then collimated and propagated to the second main reflection surface 13 . The second main reflection surface 13 collects the collimated infrared light and then focuses and propagates toward the two infrared detectors 9 , passing through the two second filters 7 After that, it becomes the infrared light of the first waveband and the second waveband respectively, and then transmitted to the center of the two infrared detectors 9 respectively. The two infrared detectors 9 convert the received infrared light into electrical signals, and the electrical signals are processed by the analog signal processing module 42 . After amplification, it is transmitted to the digital signal processing module 43, the digital signal processing module 43 converts the analog signal into a digital signal, and the digital signal is output or stored after operation; After the filter 6, it is collected by the first main reflection surface 12 and then collimated and propagated to the second main reflection surface 13. During the propagation process, the infrared light of the first band is partially absorbed by the gas to be measured, and the remaining unabsorbed infrared light ( Infrared light of the second wavelength band and part of the infrared light of the first wavelength band) are collected and collimated by the two second main reflection surfaces 13 and then focused and propagated to the two infrared detectors 9 respectively, and then transmitted to the two infrared detectors 9 after passing through the two second filters 7. At the center of the infrared detector 9, the two infrared detectors 9 convert the received infrared light into electrical signals. At this time, since part of the infrared light in the first band is absorbed by the gas to be measured, the corresponding infrared The electrical signal will weaken, and the electrical signal is amplified by the analog signal processing module 42 and then transmitted to the digital signal processing module 43. The digital signal processing module 43 converts the analog signal into a digital signal and compares and calculates the value of the digital signal when there is no gas to be measured, that is, Concentration results are available, which can be output using the communication function or stored using the storage function.

The carbon dioxide concentrations of 0%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, and 10% are sequentially introduced into the parallel dual-channel infrared gas sensor of the embodiment. The result is shown in Figure 11. It can be seen from Figure 11 that the infrared gas sensor of this embodiment can accurately and stably obtain the corresponding concentration signal response value, and the number is still accurate after continuous operation for many days. Within the range of 3%±50ppm of concentration, the precision is good.

In the parallel dual-channel infrared gas sensor of the embodiment of the present invention, the reflector 1, the support plate 2, the base 3 and the ASIC chip 4 are stacked and arranged, so that the infrared light source 8, the infrared detector 9 and the optical gas chamber are packaged at the chip level. , can achieve the effect of reducing the volume, and realize the miniaturization and integration of the infrared gas sensor; the symmetrical ventilation holes 5 on both sides enable the infrared gas sensor to be directly integrated into the airway of the gas analysis equipment, which is convenient to use and respond quickly; The use of two parallel infrared detectors 9 can correct the problem of signal drift caused by the aging of the components and the contamination inside the reflection cavity 16, and has high coupling efficiency and good light condensing effect; the reflection cavity 16 is a folded reflection structure, so that the light The infrared light source 8 and the two infrared detectors 9 are distributed at both ends of the base, which can isolate the influence of the infrared light source on the thermal element.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Various changes can be made to the above-mentioned embodiments of the present invention. That is, all simple and equivalent changes and modifications made according to the claims and descriptions of the present invention fall into the protection scope of the claims of the present invention. What is not described in detail in the present invention is conventional technical content.

Claims (10)

1. A parallel dual-channel infrared gas sensor, characterized in that it comprises a reflector, a support plate, a base and an ASIC chip stacked sequentially from top to bottom; The reflector is provided with a reflection cavity and a plurality of ventilation holes communicating with the reflection cavity; The support plate is provided with a first through hole and a second through hole, a first filter is embedded in the first through hole, and two second filters are embedded in the second through hole; The top surface of the base is provided with an infrared light source and two infrared detectors, the infrared light source is located in the first through hole and directly below the first filter, and the two infrared detectors are located in the second through hole. in the hole and respectively located directly below the two second filters, and two infrared detectors are arranged side by side relative to the infrared light source; The infrared light source and two infrared detectors are electrically connected to the ASIC chip. 2 . The parallel dual-channel infrared gas sensor according to claim 1 , wherein the inner wall of the reflection cavity comprises a first main reflection surface, two second main reflection surfaces and a first auxiliary reflection surface, and the supporting The top surface of the board is formed as a second auxiliary reflection surface, the first auxiliary reflection surface and the second auxiliary reflection surface are parallel to each other, the first main reflection surface is located directly above the first filter, and the two auxiliary reflection surfaces are parallel to each other. The second main reflection surfaces are respectively located directly above the second filters. 3 . The parallel dual-channel infrared gas sensor according to claim 2 , wherein the first main reflection surface and the two second main reflection surfaces are both compound paraboloids, and the first main reflection surface and the two second main reflection surfaces are both compound paraboloids. 4 . The cross section of at least a part of the optical path between the two main reflection surfaces is perpendicular to the surface of the base. 4 . The parallel dual-channel infrared gas sensor according to claim 2 , wherein the inner wall of the reflective cavity and the top surface of the support plate are plated with gold film, silver and silver compound film or Bragg reflection film. 5 . ;and / or, The material of the reflector and the support plate is aluminum, copper, plastic, resin, ABS material, silicon or glass; and/or, The base is a PCB and is made of FR-4 material or ceramic material, and the infrared light source and the two infrared detectors are routed at two ends of the PCB. 5 . The parallel dual-channel infrared gas sensor according to claim 1 , wherein the ventilation holes are arranged on the top of the reflector or symmetrically distributed on both sides of the reflector, and the ventilation holes are outside the ventilation holes. 6 . Covered with waterproof breathable membrane. 6 . The parallel dual-channel infrared gas sensor according to claim 1 , wherein the infrared light source is a MEMS light source or an LED light source, and the first filter is a bandpass filter or an M-I-M superstructure. 7 . 7 . The parallel dual-channel infrared gas sensor according to claim 1 , wherein the infrared detector is a pyroelectric detector chip or a photoelectric detector chip, and the second filter is a narrow-band filter. 8 . sheet or M-I-M superstructure. 8 . The parallel dual-channel infrared gas sensor according to claim 1 , wherein one of the two second filters is set to allow the infrared light of the first wavelength band to pass through, and the other is set to allow the infrared light of the second wavelength band to pass through. 9 . When infrared light passes through, the infrared light in the first wavelength band has the same absorption spectrum as the gas to be tested, and the infrared light in the second wavelength band cannot be absorbed by the gas to be tested. 9 . The parallel dual-channel infrared gas sensor according to claim 1 , wherein the base or the ASIC chip is provided with a thermistor. 10 . 10. The parallel dual-channel infrared gas sensor according to claim 9, wherein the ASIC chip integrates a power module, an analog signal processing module and a digital signal processing module, and the power module is the infrared light source, The thermistor, the infrared detector, the analog signal processing module and the digital signal processing module are powered.

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