CN115236021A - Parallel double-channel infrared gas sensor - Google Patents
Parallel double-channel infrared gas sensor Download PDFInfo
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Abstract
The invention relates to a parallel double-channel infrared gas sensor, which comprises a reflecting cover, a supporting plate, a base and an ASIC chip which are sequentially stacked from top to bottom; the reflecting cover is provided with a reflecting cavity and a plurality of air holes; the supporting plate is provided with a first through hole and a second through hole, and a first optical filter and two second optical filters are embedded in the first through hole and the second through hole respectively; the top surface of the base is provided with an infrared light source and two infrared detectors, the infrared light source is positioned under the first optical filter, the two infrared detectors are respectively positioned under the two second optical filters, and the two infrared detectors are arranged in parallel relative to the infrared light source; the infrared light source and the two infrared detectors are electrically connected with the ASIC chip. According to the parallel type double-channel infrared gas sensor, the reflecting cover, the supporting plate, the base and the ASIC chip are arranged in a stacked mode, so that the size is reduced; the reflecting cavity is of a folding reflecting structure, so that the optical path is increased; the infrared light source and the two infrared detectors are distributed at two ends of the base, and the influence of the infrared light source on the thermosensitive element can be isolated.
Description
Technical Field
The invention relates to the technical field of gas sensors, in particular to a parallel dual-channel infrared gas sensor.
Background
With the progress of science and technology and the development of economy, at present, society is gradually crossing the era of the internet of things, sensing nodes are more and more distributed, the demand of sensors is more and more, and the infrared gas sensor is widely concerned and researched by people with the advantages of high precision, long service life, good selectivity, no toxicity and the like.
The infrared gas sensor is a micro spectral analysis device, and realizes the detection of the concentration of gas by detecting the absorption intensity of the characteristic spectrum of gas molecules. Compared with other gas sensors such as an electrochemical type sensor, a catalytic combustion type sensor, a semiconductor type sensor and the like, the gas sensor has the advantages of wide application range, long service life, high sensitivity, good stability, less environmental interference factors, no poisoning, no dependence on oxygen, more gases, high cost performance, low maintenance cost, capability of on-line analysis and the like, and is widely applied to the fields of petrochemical industry, metallurgical industry and mining, air pollution detection, agriculture, medical treatment and health and the like.
The existing infrared sensor mostly uses a heating wire or an incandescent lamp as an infrared light source, a TO packaging detector as a sensitive element, gas component detection is realized through signal detection and processing, and the size of the existing infrared sensor is large and cannot meet the requirements of miniature gas sensors in certain specific occasions.
Disclosure of Invention
The invention aims to provide a parallel double-channel infrared gas sensor to solve the technical problem that the existing infrared gas sensor is too large in size.
The invention provides a parallel dual-channel infrared gas sensor, which comprises a reflecting cover, a supporting plate, a base and an ASIC chip which are sequentially stacked from top to bottom;
the reflecting cover is provided with a reflecting cavity and a plurality of air holes communicated with the reflecting cavity;
a first through hole and a second through hole are formed in the supporting plate, a first optical filter is embedded in the first through hole, and two second optical 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 positioned in the first through hole and is positioned under the first optical filter, the two infrared detectors are positioned in the second through hole and are respectively positioned under the two second optical filters, and the two infrared detectors are arranged in parallel relative to the infrared light source;
the infrared light source and the two infrared detectors are electrically connected with the ASIC chip.
Furthermore, the inner wall of the reflection cavity comprises a first main reflection surface, two second main reflection surfaces and a first auxiliary reflection surface, the top surface of the supporting plate is formed into 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 right above the first optical filter, and the two second main reflection surfaces are respectively located right above the second optical filter.
Further, the first main reflecting surface and the two second main reflecting surfaces are both compound paraboloids, and the cross section of at least one part of the light path between the first main reflecting surface and the two second main reflecting surfaces is perpendicular to the surface of the base.
Further, the inner wall of the reflecting cavity and the top surface of the supporting plate are plated with a gold film, a silver and silver compound film or a Bragg reflecting film; and/or the presence of a gas in the gas,
the reflecting cover and the supporting plate are made of aluminum, copper, plastics, resin, ABS (acrylonitrile butadiene styrene) materials, silicon or glass; and/or the presence of a gas in the atmosphere,
the base is a PCB and is made of FR-4 materials or ceramic materials, and the infrared light source and the two infrared detectors are respectively wired at two ends of the PCB.
Furthermore, the air holes are formed in the top of the reflecting cover or symmetrically distributed on two sides of the reflecting cover, and the waterproof breathable film covers the air holes.
Further, the infrared light source is an MEMS light source or an LED light source, and the first optical filter is a band-pass optical filter or an M-I-M superstructure.
Further, the infrared detector is a thermoelectric detector chip or a photoelectric detector chip, and the second optical filter is a narrow-band optical filter or an M-I-M superstructure.
Furthermore, one of the two second optical filters is set to allow infrared light of a first waveband to pass through, and the other one of the two second optical filters is set to allow infrared light of a second waveband to pass through, the infrared light of the first waveband is the same as the absorption spectrum of the gas to be detected, and the infrared light of the second waveband cannot be absorbed by the gas to be detected.
9. The side-by-side dual-channel infrared gas sensor as claimed in claim 1, wherein a thermistor is disposed on the base or ASIC chip.
Furthermore, the ASIC chip is integrated with a power module, an analog signal processing module and a digital signal processing module, wherein the power module supplies power to the infrared light source, the thermistor, the infrared detector, the analog signal processing module and the digital signal processing module.
According to the parallel double-channel infrared gas sensor, the reflecting cover, the supporting plate, the base and the ASIC chip are packaged together, so that the effect of reducing the volume can be achieved, and the miniaturization and integration of the infrared gas sensor are realized; the symmetrical air holes on the two sides enable the infrared gas sensor to be directly integrated into an air passage of gas analysis equipment for use, so that the infrared gas sensor is convenient to use and quick in response; by adopting two parallel infrared detectors, the problems of signal drift caused by aging of elements and pollution inside the reflecting cavity can be solved, the coupling efficiency is high, and the light condensation effect is good.
Drawings
FIG. 1 is a schematic diagram of a side-by-side dual-channel infrared gas sensor in accordance with an embodiment of the present invention, wherein the reflector and the support plate are shown in semi-sectional view;
FIG. 2 is an exploded view of a side-by-side dual channel infrared gas sensor according to an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a reflector of a parallel dual-channel infrared gas sensor according to an embodiment of the invention, wherein air holes are symmetrically arranged on two sides of the reflector;
FIG. 4 is a schematic structural diagram of a reflector of a side-by-side dual-channel infrared gas sensor according to another embodiment of the present invention, wherein air holes are formed in the top of the reflector;
FIG. 5 is a top view of a support plate of a side-by-side dual-channel infrared gas sensor according to an embodiment of the present invention;
FIG. 6 is a top view of a base of a side-by-side dual-channel infrared gas sensor according to an embodiment of the present invention;
FIG. 7 is a schematic optical path diagram of a side-by-side dual-channel infrared gas sensor according to an embodiment of the invention;
FIG. 8 is a graph of ray tracing simulation results for a side-by-side dual channel infrared gas sensor according to an embodiment of the present invention;
FIG. 9 is a graph of irradiance distributions across the surfaces of two infrared detectors of a side-by-side dual-channel infrared gas sensor in accordance with an embodiment of the present invention;
FIG. 10 is a schematic diagram of the internal structure of an ASIC chip of a side-by-side dual-channel infrared gas sensor according to an embodiment of the present invention;
fig. 11 is a graph showing the results of performance tests of the side-by-side dual-channel infrared gas sensor according to the embodiment of the present invention.
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
Reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic may be included in at least one implementation of the present application. In the description of the present application, it is to be understood that the terms "upper", "lower", "top", "bottom", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing the present application and simplifying the description, and do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," and the like are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the application described herein may be implemented 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, which includes a reflector 1, a supporting plate 2, a base 3, and an ASIC chip 4 stacked in sequence from top to bottom, as shown in fig. 3, the reflector 1 has a reflective cavity 16, a plurality of air vents 5 communicating with the reflective cavity 16 are symmetrically disposed on two sides of the reflector 1, as shown in fig. 4, in another embodiment, as shown in fig. 4, the air vents 5 may also be disposed on the top of the reflector 1, a waterproof air-permeable membrane 11 covers the air vents 5, as shown in fig. 5, a first through hole 21 and a second through hole 22 are disposed on the supporting plate 2, respectively, a first optical filter 6 is embedded in the first through hole 21, and two second optical 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 is provided with an infrared light source 8 and two infrared detectors 9, the infrared light source 8 is located in the first through hole 21 and is located right below the first optical filter 6, the two infrared detectors 9 are located in the second through hole 22 and are respectively located right below the two second optical filters 7, and the two infrared detectors 9 are arranged in parallel relative 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 for providing a signal processing function and is electrically connected with the infrared light source 8 and the infrared detector 9; when the gas concentration is measured, gas enters the reflection cavity 16 from the air holes 5, the ASIC chip 4 controls the infrared light source 8 to periodically emit light, infrared light enters the reflection cavity 16 after passing through the first optical filter 6, the infrared light is reflected in the reflection cavity 16 and then reaches the infrared detector 9 through the second optical filter 7, the infrared detector 9 converts the received infrared light into an electric signal and transmits the electric signal to the ASIC chip 4, and the gas concentration can be obtained after the processing of the ASIC chip 4.
In this embodiment, the reflector 1 and the supporting plate 2, and the supporting plate 2 and the base 3 can be connected by sealant, so that after the connection, the reflection cavity 16 is communicated with the outside only through the air holes 5, so that the measurement result is more accurate.
It should be understood that the reflector 1 and the supporting plate 2 and the base 3 may be connected in other sealing manners, for example, a sealing ring is disposed between the two and then fastened by a screw, a snap, a pin, etc., which is not limited in this respect.
The base 3 and the ASIC chip 4 can be electrically connected by a flip-chip bonding process or conductive adhesive, 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 7, the inner wall of the reflective cavity 16 of the reflective mask 1 includes a first main reflective surface 12, two second main reflective surfaces 13 and a first auxiliary reflective surface 14, the top surface of the supporting plate 2 is formed as a second auxiliary reflective surface 15, the first auxiliary reflective surface 14 and the second auxiliary reflective surface 15 are parallel to each other, the first main reflective surface 12 and the two second main reflective surfaces 13 are disposed opposite to each other, the first main reflective surface 12 is located right above the first optical filter 6, and the two second main reflective surfaces 13 are respectively located right above the two second optical filters 7.
The light is folded in the transmission process of the reflection cavity 16, namely the light is transmitted to the two infrared detectors 9 after being reflected for multiple times. Specifically, 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 optical filter 6, the first main reflection surface 12 has a function of collimating light, most of collected infrared light is reflected into infrared light parallel to the first auxiliary reflection surface 14, the reflected infrared light is uniformly transmitted to the two second main reflection surfaces 13 in a V shape, a small amount of residual infrared light can be reflected by the first auxiliary reflection surface 14 and the second auxiliary reflection surface 15 and then transmitted to the two second main reflection surfaces 13, the two second main reflection surfaces 13 have a function of focusing light, and the received infrared light can be focused on centers of the surfaces of the two infrared detectors 9 through the two second optical filters 7 after being reflected. The cross section of at least a part of the optical path between the first main reflecting surface 12 and the two second main reflecting surfaces 13 may be disposed perpendicular to the surface of the base to reduce the number of reflections, thereby reducing the loss of infrared light. Due to the folding reflection design, the light path is increased, the gas molecules to be detected can be fully absorbed, the attenuation of infrared light reaching the infrared detector end is increased, and the sensitivity is improved.
In this embodiment, the first main reflective surface 12 and the two second main reflective surfaces 13 are both compound paraboloids, the above-mentioned reflective function can be realized by setting parameters of the paraboloids, and the setting of the parameters is common knowledge in the optical field, and reference may be made to a compound paraboloid condenser, which is not described herein again.
It should be noted that the first main reflective surface 12 and the two second main reflective surfaces 13 may also be configured as a plane, a spherical surface, an ellipsoid or other types of curved surfaces, and only the incident light and the emergent light passing through the reflective surfaces need to obtain the incident angle and the reflection angle of 30 ° to 60 °, respectively.
In order to reduce the transmission loss of infrared light in the reflective cavity 16, the inner wall of the reflective cavity 16 and the top surface of the supporting plate 2 are coated with, but not limited to, gold film, silver and its compound film or bragg reflective film.
As shown in fig. 8, simulation proves that the reflective cavity 16 of the present invention can collect and collimate infrared light emitted by the infrared light source 8, the light is dispersed and transmitted in a V-shape to the two infrared detectors 9 in a direction parallel to the base 3, and the second main reflective surface 13 can collect the transmitted infrared light and focus on the surface of the infrared detectors 9; in conjunction with the light transmission process of fig. 7, fig. 9 is a distribution diagram of irradiance on the surfaces of two infrared detectors in the embodiment of the present invention, and it can be seen from the brightness and the maximum value of the scale in the diagram that the present invention can improve the coupling efficiency and obtain large irradiance on the surfaces of two infrared detectors 9.
The infrared light source 8 can be selected from but not limited to a MEMS light source or an LED light source, can radiate wide-spectrum infrared light, and the first optical filter 6 is a band-pass optical filter; the first optical filter 6 can also be replaced by an M-I-M superstructure (namely a three-layer structure of a metal antenna, a dielectric layer and a metal back plate), and is directly manufactured on the surface of the infrared light source 8 to realize corresponding narrow-band infrared light emission. For example, in the present embodiment, the infrared light source 8 is configured as a MEMS light source, and is implemented by using a MEMS processing technology, and is connected to the base 3 by using a wire bonding method, so that a wide spectrum infrared light can be emitted.
The infrared detector 9 may be selected from, but not limited to, a pyroelectric type detector chip or a photoelectric type detector chip. The two second filters 7 are both narrow-band filters. The second optical filter 7 can also be replaced by an M-I-M superstructure, and is directly manufactured on the surface of the infrared detector 9 to realize corresponding narrow-band infrared light detection. For example, in the present embodiment, the infrared detector 9 is a pyroelectric detector chip, and is implemented by using an MEMS process, and is connected to the base 3 by using a wire bonding method.
One of the two second optical filters 7 is configured to allow infrared light of a first wavelength band to pass through, and the other is configured to allow infrared light of a second wavelength band to pass through, the infrared light of the first wavelength band is configured to be the same as an absorption spectrum of the gas to be detected and can be absorbed by the gas to be detected, and the infrared light of the second wavelength band is configured to be not absorbed by the gas to be detected, so that one of the two infrared detectors 9 is used for detecting an infrared signal which can be absorbed by the gas to be detected, the other is used for detecting an infrared signal which is not absorbed by the gas to be detected, so as to detect the infrared detector 9 of the first wavelength band as a reference signal, and the other is used as a reference signal, and by comparing the two reference signals with the reference signal (for example, processing by using operation methods such as difference, proportion, normalization, and the like), the reference signal can be compensated, the obtained result is more accurate, and the problem of signal drift caused by aging of elements and pollution inside the reflective cavity 16 can be corrected. For example, taking carbon dioxide gas as an example, since both carbon dioxide and water molecules absorb infrared light with the same spectrum (i.e. the first wavelength band) as carbon dioxide, when only one infrared detector is provided, it is not possible to determine how much infrared light is absorbed by carbon dioxide and how much is absorbed by water molecules, in the present invention, by providing two infrared detectors, the reference signal can acquire the variation of infrared light of the first wavelength band, the reference signal can acquire the variation of infrared light of the second wavelength band, since carbon dioxide cannot absorb infrared light of the second wavelength band, the variation of infrared light of the second wavelength band is the amount absorbed by water molecules, and the variation of infrared light of the first wavelength band and the variation of infrared light of the second wavelength band are normalized to obtain the amount of infrared light absorbed by carbon dioxide, thereby obtaining the concentration of carbon dioxide.
Different gases have different absorption spectra due to differences in their molecular structures, concentrations, and energy distributions, and therefore the specific values of the first and second wavelength bands can be modified as needed to detect the concentrations of different gases to be measured, i.e., the gas sensor can detect the concentration of carbon dioxide when the first wavelength band is set to the absorption spectrum of carbon dioxide and the gas sensor can detect the concentration of nitrogen when the first wavelength band is set to the absorption spectrum of nitrogen.
The first filter 6 is configured to allow infrared light of the wavelength bands corresponding to the two second filters 7 to pass through, that is, the wavelength band range of the infrared light allowed to pass through by the first filter 6 is a set of the first wavelength band and the second wavelength band. For example in the detection of CO 2 In the gas application, if the first wavelength band is 4.2-4.3 μm and the second wavelength band is 3.9-4.0 μm, the first filter 6 allows the infrared light to pass through in a wavelength band range of at least 3.9-4.3 μm.
With continued reference to fig. 2 and 6, a thermistor 10 may be further disposed on the base 3, and is located near the two infrared detectors 9, and is used for providing an ambient temperature correction coefficient, so as to ensure that the gas sensor of the present invention can work normally at various temperatures, and realize gas quantitative detection, and the thermistor 10 is also electrically connected to the ASIC chip through the base 3. Of course, the thermistor 10 may also be formed directly on the ASIC chip. The thermistor 10 may be selected from, but not limited to, semiconductor or ceramic materials.
In this embodiment, the thermistor 10 is made of a ceramic material and is integrated between the two infrared detectors 9 of the base 3, and the resistor is made of, but not limited to, 100K Ω.
The materials of the reflecting cover 1 and the supporting plate 2 can be selected from but not limited to metal materials such as aluminum, copper and the like, and are realized by adopting a micro-machining method; or the printing is realized by selecting but not limited to plastic, resin, ABS material and the like and adopting a film pressing process, an injection molding process or a 3D printing technology; or, alternatively but not limited to, silicon or glass materials, using MEMS processing techniques. In the present embodiment, the reflector 1 and the support plate 2 are made of copper and are micro-machined.
The base 3 can be a Printed Circuit Board (PCB), and FR-4 or a ceramic material is adopted, the PCB is provided with a plurality of wires respectively connecting the infrared light source 8 and the two infrared detectors 9 at two ends, and the infrared light source is isolated as a main heating element to influence the three heat sensitive elements of the two infrared detectors 9 and the thermistor 10 (the heat conductivity in the direction of the electrical connection line is 80W/(mK), and the heat conductivity in the direction of the electrical connection line is not 0.3W/(mK)). In some possible embodiments, the base 3 may also be an aluminum base or a copper base.
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 provide voltages of, but not limited to, 2.8V, 3V, 3.3V, 4V, 4.5V, or 5V to 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, respectively. The analog signal processing module 42 can process at least two analog signals, can realize but not limited to a band-pass filtering function of 0.2-2 Hz, and can realize adjustable gain within a range of 1-10000 times. The analog signal processing module 42 can realize signal acquisition, signal amplification and signal filtering functions. The digital signal processing module 43 may be but is not limited to an FPGA chip or an ARM core chip, and the digital signal processing module 43 has a storage function and may have but is not limited to an internal storage space of 1M, 2M, or 4M; the digital signal processing module 43 has analog-to-digital conversion capability, and has more than two ADC sampling channels, and the number of sampling bits may be, but is not limited to, 12 bits, 16 bits, 18 bits or higher; the digital signal processing module 43 has logic control and communication functions, can control the switching of the infrared light source 8 and realize basic logic operation, can transmit the operated signal to an external device, and can receive or store 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, thereby encapsulating the infrared light source 8, the infrared detector 9, and the optical air cell together,the volume can be reduced, and the obtained infrared gas sensor has length less than 15mm, width less than 13mm, height less than 7mm, or total volume less than 1500mm 3 The miniaturization and integration of the infrared gas sensor are realized.
The working principle of the parallel dual-channel infrared gas sensor (the infrared light source is a MEMS light source, and the infrared detector is a pyroelectric detector) of the present embodiment will be described as follows:
after electrification, the ASIC chip controls the infrared light source to periodically turn on light, when no gas to be detected exists, diffused infrared light emitted by the infrared light source 8 passes through the first optical filter 6 and then becomes infrared light containing a first wave band and a second wave band, the infrared light is collected by the first main reflecting surface 12 and then is transmitted to the second main reflecting surface 13 in a collimation mode, the second main reflecting surface 13 collects collimated infrared light and then is focused and transmitted to the two infrared detectors 9, the infrared light passes through the two second optical filters 7 and then becomes infrared light of the first wave band and the second wave band respectively and then is transmitted to the centers of the two infrared detectors 9 respectively, the two infrared detectors 9 convert the received infrared light into electric signals, the electric signals are amplified by the analog signal processing module 42 and then are transmitted to the digital signal processing module 43, the digital signal processing module 43 converts analog signals into digital signals, and the digital signals are output or stored after operation; when gas to be detected exists, diffused infrared light emitted by the infrared light source 8 passes through the first optical filter 6, is collected by the first main reflecting surface 12 and then is collimated to be transmitted to the second main reflecting surface 13, infrared light in a first waveband is partially absorbed by the gas to be detected in the transmission process, and the rest unabsorbed infrared light (including infrared light in a second waveband and infrared light in a partial first waveband) is collected and collimated by the two second main reflecting surfaces 13, then is respectively focused and transmitted to the two infrared detectors 9, passes through the two second optical filters 7 and then is transmitted to the centers of the two infrared detectors 9, the two infrared detectors 9 convert the received infrared light into electric signals, at this time, as part of the infrared light in the first waveband is absorbed by the gas to be detected, electric signals detected by the corresponding infrared detectors 9 are weakened, the electric signals are amplified by the analog signal processing module 42 and then are transmitted to the digital signal processing module 43, the digital signal processing module 43 converts the analog signals into digital signals, and compares and calculates the digital signals with digital signal values when the gas to be detected does not exist, concentration results can be obtained, and can be output or stored by using a communication function.
The carbon dioxide concentration of 0%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8% and 10% gas is sequentially introduced into the parallel dual-channel infrared gas sensor of the embodiment, and the result is shown in fig. 11, and it can be seen from fig. 11 that the infrared gas sensor of the embodiment can accurately and stably obtain the corresponding concentration signal response value, and still accurately indicate after continuous operation for many days, and the accuracy is good within the range of 3% ± 50ppm of the actual concentration.
According to the parallel double-channel infrared gas sensor provided by the embodiment of the invention, the reflector 1, the supporting plate 2, the base 3 and the ASIC chip 4 are stacked, so that an infrared light source 8, an infrared detector 9, an optical gas chamber and the like are packaged at a chip level, the effect of reducing the volume can be achieved, and the miniaturization and integration of the infrared gas sensor are realized; the air holes 5 which are symmetrical on two sides enable the infrared gas sensor to be directly integrated into an air passage of gas analysis equipment for use, so that the use is convenient, and the response is rapid; by adopting two parallel infrared detectors 9, the problems of signal drift caused by aging of elements and pollution inside the reflecting cavity 16 can be solved, the coupling efficiency is high, and the light condensation effect is good; the reflecting cavity 16 is a folding reflecting structure, so that the optical path is increased; the infrared light source 8 and the two infrared detectors 9 are distributed at two ends of the base, and the influence of the infrared light source on the thermosensitive element can be isolated.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and various modifications may be made to the above-described embodiment of the present invention. All simple and equivalent changes and modifications made according to the claims and the content of the specification of the present application fall within the scope of the claims of the present patent application. The invention has not been described in detail in order to avoid obscuring the invention.
Claims (10)
1. A parallel double-channel infrared gas sensor is characterized by comprising a reflecting cover, a supporting plate, a base and an ASIC chip which are sequentially stacked from top to bottom;
the reflecting cover is provided with a reflecting cavity and a plurality of air holes communicated with the reflecting cavity;
a first through hole and a second through hole are formed in the supporting plate, a first optical filter is embedded in the first through hole, and two second optical 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 positioned in the first through hole and is positioned under the first optical filter, the two infrared detectors are positioned in the second through hole and are respectively positioned under the two second optical filters, and the two infrared detectors are arranged in parallel relative to the infrared light source;
the infrared light source and the two infrared detectors are electrically connected with the ASIC chip.
2. The infrared gas sensor as set forth in claim 1, wherein 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 supporting plate 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 optical filter, and the two second main reflection surfaces are respectively located directly above the second optical filter.
3. The side-by-side dual-channel infrared gas sensor as claimed in claim 2, wherein the first and second primary reflective surfaces are each compound paraboloids, and a cross-section of at least a portion of a light path between the first and second primary reflective surfaces is perpendicular to a surface of the base.
4. The side-by-side dual-channel infrared gas sensor according to claim 2, wherein the inner wall of the reflection cavity and the top surface of the support plate are plated with a gold film, a silver and silver compound film or a bragg reflection film; and/or the presence of a gas in the atmosphere,
the reflector and the support plate are made of aluminum, copper, plastic, resin, ABS (acrylonitrile butadiene styrene) material, silicon or glass; and/or the presence of a gas in the gas,
the base is a PCB and is made of FR-4 materials or ceramic materials, and the infrared light source and the two infrared detectors are respectively wired at two ends of the PCB.
5. The parallel dual-channel infrared gas sensor as claimed in claim 1, wherein the ventilation holes are arranged on the top of the reflector or symmetrically distributed on two sides of the reflector, and the ventilation holes are covered with waterproof and breathable films.
6. The side-by-side dual-channel infrared gas sensor as claimed in 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. The side-by-side dual-channel infrared gas sensor as claimed in 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 or an M-I-M superstructure.
8. The parallel two-channel infrared gas sensor as set forth in claim 1, wherein one of the two second filters is configured to allow infrared light of a first wavelength band to pass through and the other is configured to allow infrared light of a second wavelength band to pass through, the first wavelength band of infrared light having the same absorption spectrum as the gas to be measured, and the second wavelength band of infrared light being not absorbed by the gas to be measured.
9. The side-by-side dual-channel infrared gas sensor of claim 1 wherein a thermistor is disposed on the base or ASIC chip.
10. The dual-channel infrared gas sensor of claim 9, wherein the ASIC chip integrates a power module, an analog signal processing module, and a digital signal processing module, the power module powering the infrared light source, the thermistor, the infrared detector, the analog signal processing module, and the digital signal processing module.
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| CN202210760500.XA CN115236021A (en) | 2022-06-30 | 2022-06-30 | Parallel double-channel infrared gas sensor |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117553252A (en) * | 2024-01-12 | 2024-02-13 | 深圳市美思先端电子有限公司 | MEMS infrared light source component and detection device based on piezoelectric film modulation |
| CN117664864A (en) * | 2024-01-31 | 2024-03-08 | 上海烨映微电子科技股份有限公司 | Gas detection device |
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2022
- 2022-06-30 CN CN202210760500.XA patent/CN115236021A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117553252A (en) * | 2024-01-12 | 2024-02-13 | 深圳市美思先端电子有限公司 | MEMS infrared light source component and detection device based on piezoelectric film modulation |
| CN117664864A (en) * | 2024-01-31 | 2024-03-08 | 上海烨映微电子科技股份有限公司 | Gas detection device |
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