Light-enhanced mixed gas detection device and testing method

Abstract

The application provides a light-enhanced mixed gas detection device, comprising an outer cylinder, a sensor array, and a sensing group arranged on the outer wall of an inner cylinder concentrically arranged in the outer cylinder, wherein the outer cylinder and the annular chamber of the inner cylinder form a first chamber allowing the flow of mixed gas, and the sensing group comprises a plurality of gas-sensitive materials arranged along the axial direction of the inner cylinder and used for contacting the gas.

Description

Technical Field

[0001] This invention relates to the field of detector design and application in gas sensing, specifically to a light-enhanced mixed gas detection device and a testing method. Background Technology

[0002] Industrial environments often involve a complex mixture of gases, including toxic, harmful, and flammable gases, which typically do not exist independently. While there is considerable research on room temperature gas sensors, most suffer from low integration. Combining multiple independent gas sensors into an array often results in inconsistent interfaces, performance, and control circuits, making it difficult to meet field requirements in terms of array size and response consistency.

[0003] With advancements in micro / nano material fabrication processes, the enhanced performance of room-temperature gas-sensitive materials under ultraviolet and visible light irradiation has attracted widespread attention. This is because when photon energy matches the bandgap of a semiconductor, irradiation of the nanomaterial causes valence band electrons to be excited and cross the bandgap to reach the conduction band, forming photogenerated electron-hole pairs. Simultaneously, illumination increases the adsorption capacity and concentration of adsorption centers on the semiconductor surface, thereby improving chemisorption efficiency and enabling the gas-sensitive element to exhibit good sensitivity to the target gas at room temperature. Using ultraviolet and visible light sources for excitation to enhance room-temperature gas-sensing performance is an effective method.

[0004] However, existing gas detectors are mainly based on principles such as electrochemistry and micro / nano semiconductor materials, and do not take into account the need for light-enhanced sensing characteristics and array integration.

[0005] CN108318544A discloses a visible light-enhanced room-temperature NO2 gas sensor based on a three-dimensional inverse opal structure In2O3-ZnO composite nanosensitive material and its fabrication method, belonging to the field of semiconductor oxide gas sensor technology. The device has a side-heated structure, consisting of an Al2O3 ceramic tube substrate with two parallel, ring-shaped, and discrete gold electrodes on its outer surface; a three-dimensional inverse opal structure In2O3-ZnO composite nanosensitive material coated on the outer surface of the ceramic tube and the gold electrodes; and a white light-emitting diode positioned perpendicular to the axial direction of the ceramic tube. Test results show that the sensor has a sensitivity of up to 54.3 for 5 ppm NO2, a detection limit of 250 ppb, fast response and recovery rates, and good selectivity and repeatability. However, the device has low integration and significant uneven illumination, hindering its widespread application in practical operation.

[0006] Therefore, it is desirable in the art to provide a light-enhanced mixed gas detection device and a testing method to solve the above-mentioned technical problems. Summary of the Invention

[0007] The purpose of this invention is to provide a light-enhanced mixed gas detection device, which can simultaneously identify multiple gases in a mixed gas by arranging multiple sets of gas-sensitive materials.

[0008] According to a first aspect of the present invention, a light-enhanced mixed gas detection device is provided, comprising an outer cylinder, and

[0009] The sensor array includes an inner cylinder concentrically arranged within the outer cylinder, and a sensor group disposed on the outer wall of the inner cylinder.

[0010] The outer cylinder and the inner cylinder form a first chamber that allows the flow of mixed gas. The sensing group includes a plurality of gas-sensitive materials disposed on the inner wall of the inner cylinder and used to contact the gas.

[0011] In one embodiment, the gas-sensitive material is a hydrogen-sensitive material, and the gas-sensitive material includes at least two of nano-ZnO, TiO2, and SnO2.

[0012] In one embodiment, the inner cylinder has a second chamber for placing an irradiation group, the light emitted by the irradiation group being able to accelerate the gas-sensing process between the gas-sensitive material and the mixed gas.

[0013] In one embodiment, the outer cylinder is made of an opaque material, and the inner cylinder is made of a transparent material.

[0014] In one embodiment, the illumination group includes lamp posts arranged longitudinally and a plurality of lamp beads arranged at axial intervals along the lamp posts.

[0015] The sensor array also includes mounting bases disposed at both ends of the inner cylinder and connected to the lamp post, as well as adjusters for the lamp beads.

[0016] In one embodiment, a plurality of the gas-sensitive materials are arranged circumferentially or axially spaced on the inner wall of the inner cylinder.

[0017] In one embodiment, the lamp bead contains a wick of the same color.

[0018] In one embodiment, the lamp bead is located within the range of the gas-sensitive material in the axial or circumferential direction, and the lamp bead contains a variety of different colored wicks adapted to the gas-sensitive material.

[0019] In one embodiment, a partition plate for blocking the light path is provided between two adjacent gas-sensitive materials, and the partition plate is fixed to the inner cylinder.

[0020] In one embodiment, the light-enhanced mixed gas detection device further includes a plurality of sensing electrodes respectively connected to both ends of the gas-sensitive material and used to record resistance changes.

[0021] According to a second aspect of the present invention, a testing method is provided, which utilizes a light-enhanced mixed gas detection device as described above, comprising the following steps:

[0022] S1. Coat the outer wall of the inner cylinder with multiple different gas-sensitive materials;

[0023] S2. Fix the irradiation group on the mounting base and test the response sensitivity of the sensor array through the sensing electrodes.

[0024] In one embodiment, the gas-sensitive material and organic solvent are placed in a mortar and ground thoroughly before coating.

[0025] In one embodiment, step S2 further includes a testing step:

[0026] First, adjust the light radiation intensity of the lamp bead using the regulator. After the resistance measured by the sensing electrode stabilizes, record the resistance R0 at this time.

[0027] Then, a mixed gas is injected into the first chamber, and the mixed gas comes into contact with the gas-sensitive material to perform a gas-sensitive effect. After the measured resistance of the sensing electrode stabilizes, the resistance R1 at this time is recorded.

[0028] Finally, the response sensitivity of the sensor array is obtained, i.e.

[0029] Compared with the prior art, the advantages of the present invention are as follows:

[0030] Firstly, the sensor array in this invention can simultaneously arrange multiple sets of gas-sensitive materials to enable it to simultaneously identify multiple gases in a mixed gas.

[0031] Preferably, this device uses a pumping or diffusion method to allow the mixed gas to pass through the first chamber of the sensor array, thereby causing different changes in the sensitive material (the mixed gas and the sensitive material undergo a gas-sensitive effect), and then the sensor resistance change is detected by the sensing electrode. The central processing unit then analyzes the gas concentration information through a pre-programmed procedure to realize data transmission and alarm functions.

[0032] Secondly, this invention employs miniature LED beads, which are small in size, consume little energy, and have a long lifespan, thus improving the overall integration and energy efficiency of the sensor. Because the LED beads are located in the second chamber, and the gas-sensitive material completely encapsulates them, the light emitted by the beads is fully absorbed by the gas-sensitive material, further enhancing light utilization. Therefore, under the same enhancement effect, the LED beads in this device have the advantage of lower power consumption.

[0033] Furthermore, the lamp beads in this invention can use lamp cores of the same color, or different colors (i.e., different emission wavelengths) of lamp cores can be selected according to the characteristics of different gas-sensitive materials, and different lamp beads can also be independently controlled to open and close.

[0034] Furthermore, due to the inconsistent quality of LED chips on the market, they are prone to damage during prolonged use, which can severely impact the lifespan of the entire sensor. Therefore, this device mounts the LED chips on the lamp post rather than directly fixing them to the inner cylinder. This allows for replacement without altering other structural components, thereby extending the device's lifespan. Attached Figure Description

[0035] The invention will now be described in detail with reference to the accompanying drawings, in which:

[0036] Figure 1 This is a cross-sectional view of the light-enhanced mixed gas detection device according to the present invention;

[0037] Figure 1a for Figure 1 A magnified view of a portion of the image;

[0038] Figure 1b for Figure 1 Top view;

[0039] Figure 2 This is a top view of the light-enhanced mixed gas detection device according to the present invention;

[0040] Figure 3 The schematic diagram illustrates the structure of the light-enhanced mixed gas detection device according to the present invention;

[0041] Figure 4 An embodiment of the light-enhanced mixed gas detection device according to the present invention is illustrated schematically;

[0042] Figure 5 An embodiment of the light-enhanced mixed gas detection device according to the present invention is illustrated schematically;

[0043] Figure 6 The schematic diagram illustrates the response sensitivity of the sensor array under both illumination and non-illumination conditions.

[0044] In the accompanying drawings, the same parts use the same reference numerals. The drawings are not drawn to scale.

[0045] The meanings of the reference numerals in the attached figures are as follows:

[0046] 11 Outer cylinder; 12 Inner cylinder; 13 Gas-sensitive material; 14 Irradiation group; 15 Sensing electrode; 16 Isolation plate; 17 Heating wire;

[0047] 21 First chamber; 22 Second chamber. Detailed Implementation

[0048] To make the technical solutions and advantages of the present invention clearer, exemplary embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not an exhaustive list of all embodiments. Furthermore, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0049] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0050] In this invention, unless otherwise explicitly specified and limited, the terms "installation", "connection", "linking", "fixing", etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components.

[0051] Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0052] The invention will now be further described with reference to the accompanying drawings.

[0053] Figure 1 This is a cross-sectional view of the light-enhanced mixed gas detection device according to the present invention;

[0054] Figure 2 This is a top view of the light-enhanced mixed gas detection device according to the present invention;

[0055] Figure 3 The schematic diagram illustrates the structure of the light-enhanced mixed gas detection device according to the present invention.

[0056] like Figures 1-3As shown, according to a first aspect of the present invention, a light-enhanced mixed gas detection device is provided, mainly comprising an outer cylinder 11 and a sensor array disposed within the outer cylinder 11. Preferably, the sensor array comprises an inner cylinder 12 concentrically arranged within the outer cylinder 11, and a sensing group disposed on the outer wall of the inner cylinder 12.

[0057] In this invention, such as Figures 1-3 As shown, the annular cavity between the outer cylinder 11 and the inner cylinder 12 is configured as the first chamber 21. The first chamber 21 allows the flow of the gas mixture to be detected, facilitating contact between the gas mixture and the sensing array to generate a gas-sensitive effect. Preferably, porous grids configured in annular shapes are provided at both ends of the first chamber 21, thereby facilitating the guidance of the gas mixture in and out.

[0058] Preferably, a waterproof and breathable membrane is provided inside the porous grid. This can effectively reduce the impact of humidity on the testing process and further prevent dust from entering and contaminating the gas-sensitive material 13.

[0059] Figure 1a for Figure 1 A magnified view of a portion of the image. Figure 1b for Figure 1 Top view.

[0060] In one embodiment of the present invention, the sensing group is composed of a plurality of gas-sensitive materials 13. Preferably, as shown in the figure... Figures 1-1b As shown, multiple gas-sensitive materials 13 are arranged at intervals along the circumference of the inner cylinder 12, and each of the multiple gas-sensitive materials 13 can contact the mixed gas to generate a gas-sensitive effect, thereby making it easier to identify different components in the mixed gas.

[0061] In this embodiment, the gas-sensitive material 13 is constructed as a long strip structure arranged longitudinally, and multiple gas-sensitive materials 13 are arranged at intervals along the circumference of the inner cylinder 12.

[0062] In other embodiments, such as Figure 4 As shown, multiple gas-sensitive materials 13 are arranged at intervals along the axial direction of the inner cylinder 12, and each of the multiple gas-sensitive materials 13 can contact the mixed gas to generate a gas-sensitive effect, thereby making it easier to identify different components in the mixed gas.

[0063] In this embodiment, the gas-sensitive material 13 is constructed in a ring shape, and multiple gas-sensitive materials 13 are arranged at intervals along the axial direction of the inner cylinder 12.

[0064] In one embodiment of the present invention, the gas-sensitive material 13 is preferably a room-temperature hydrogen-sensitive material. Preferably, the gas-sensitive material 13 includes, but is not limited to, nano-ZnO, TiO2, and SnO2. In this invention, doping, loading, compositing, morphology control, and other methods are used to improve the response performance of the gas-sensitive material 13 under room-temperature conditions, thereby ensuring the accuracy of identifying various components in the mixed gas.

[0065] In one embodiment, before the gas-sensitive material 13 is coated onto the outer wall of the inner cylinder 12, it must be dispersed in a suitable organic solvent (e.g., ethanol, acetone, glycerol, terpineol, etc.) and then ground in an agate mortar to ensure that the gas-sensitive material 13 is evenly dispersed in the organic solvent.

[0066] Typically, the mass ratio of organic solvent to gas-sensitive material 13 is 0.1 to 10, preferably 1:1. This is because if too much organic solvent is dissolved, the dispersion of gas-sensitive material 13 will be too thin, making it impossible to coat onto the substrate; if the amount of organic solvent is not too small, the dispersion of gas-sensitive material 13 will be too thick, resulting in uneven distribution of the material coated on the substrate, further affecting the gas-sensitive performance.

[0067] Furthermore, different types of organic solvents have different boiling points, with an optimal boiling point of 80-250℃. During the drying process, if organic solvents with excessively low boiling points evaporate too quickly, they are prone to cracking; similarly, if organic solvents with excessively high boiling points evaporate too slowly and are difficult to remove. Therefore, it is necessary to select the appropriate type and amount of organic solvent.

[0068] In this invention, screen printing, spraying or other methods can be used when coating the sensitive material 13 to further achieve precise control of the coating area.

[0069] According to the present invention, such as Figures 1-3 As shown, the inner cylinder 12 has an internal structure of a second chamber 22. Concentrically arranged irradiation groups 14 are provided within the second chamber 22. Preferably, the irradiation groups 14 function as a light source in this invention, capable of completely irradiating the gas-sensitive material 13 with their emitted light, thereby effectively accelerating the gas-sensing process between the mixed gas and the gas-sensitive material 13.

[0070] The mechanism of the gas-sensitive process mentioned above is as follows:

[0071] First, oxygen molecules in the air adsorb onto the surface of the gas-sensitive material 13, forming adsorbed oxygen molecules. These adsorbed oxygen molecules then capture electrons from the gas-sensitive material 13 to form O2- ions, further forming an electron depletion layer. However, when the operating temperature is below 150℃, the adsorbed oxygen molecules mainly exist in the form of O2- ions, while when the operating temperature is above 150℃, the O2- ions will continue to capture electrons to form O- ions. Therefore, for SnO2, an n-type semiconductor, when it is placed in air, the number of charge carriers (electrons) decreases, and the resistance increases.

[0072] However, when the gas-sensitive material 13 comes into contact with a reducing gas (such as hydrogen sulfide, ammonia, etc.), the reducing gas is first adsorbed onto its surface, forming an adsorbed gas state. This adsorbed gas then reacts with O- ions, releasing electrons from the O- ions. The released electrons return to the gas-sensitive material 13, increasing the charge carriers and thus reducing its resistance.

[0073] Clearly, the entire process eventually reaches an adsorption-desorption equilibrium, at which point the resistance remains unchanged, thus reaching an equilibrium value. When the gas concentration in the environment changes, the resistance continues to change until a new equilibrium value is reached. The percentage change in resistance, i.e., the response value, is related to the carrier concentration of the gas-sensitive material 13 and the number of active sites on its surface. The time required to reach a new equilibrium state from the initial state, i.e., the response recovery time, is related to the material's specific surface area and operating temperature. Notably, the material's resistance affects its operating temperature.

[0074] In one embodiment, the outer cylinder 11 is made of an opaque material. The opaque material is, for example, metal, plastic, ceramic, or a light-blocking coating is added to the surface of the outer shell. The purpose is to effectively prevent external light sources from shining into the gas-sensitive material 13 inside the sensor array, thereby improving the accuracy of the test results of this device.

[0075] In addition, both the outer cylinder 11 and the porous grid are treated with anti-static agents. This effectively prevents the generation of electric sparks during operation, thereby effectively protecting the mixed gas injected into the first chamber 21 and ensuring safety and stability during the test.

[0076] In one embodiment, the inner cylinder 12 is made of a transparent material. The transparent material is, for example, a highly transparent material such as glass, quartz, or plastic. The purpose is to ensure that the light emitted by the irradiation group 14, which serves as the light source, can fully pass through the inner cylinder 12 and be absorbed by the gas-sensitive material 13, so as to further accelerate the gas-sensing process between the mixed gas and the gas-sensitive material 13.

[0077] In one embodiment of the invention, the irradiation group 14 includes lamp posts arranged longitudinally in the inner cylinder 12, and a plurality of lamp beads spaced apart on the lamp posts. Furthermore, the sensor array also includes a mounting base and an adjuster. Preferably, the mounting base is installed at both ends of the inner cylinder 12 to facilitate heat dissipation from the lamp beads, thereby ensuring stable operation of the lamp beads. Preferably, the lamp posts are fixed to the mounting base, and the adjuster is connected to both the mounting base and the lamp beads, thereby enabling adjustment of the light radiation intensity of the lamp beads by adjusting the input current.

[0078] Preferably, the mounting base is connected to the inner cylinder 12 by means of threads, snaps, or inlays, thereby facilitating subsequent opening for replacement of the lamp beads. Preferably, the mounting base is made of opaque, non-conductive materials such as plastic or ceramic, which can prevent external light sources from shining into the gas-sensitive material 13 inside the sensor to protect the sensor. At the same time, the surface of the material is treated with anti-static agents to prevent electric sparks from being generated during use and igniting flammable gases.

[0079] In this invention, all LED beads can use LED chips of the same color, or different colors (i.e., different emission wavelengths) of LED chips can be selected based on the characteristics of different gas-sensitive materials 13. Preferably, different LED beads can be independently controlled to turn on and off.

[0080] Preferably, each LED bead is located within the range of one gas-sensitive material 13 in either the axial or circumferential direction. In other words, one LED bead corresponds to only one gas-sensitive material 13, thereby ensuring that the light is evenly distributed across each gas-sensitive material 13.

[0081] In this invention, if lamp cores with different emission wavelengths are used, then it is necessary to... Figure 1a or Figure 3 As shown, a partition plate 16 is provided between two adjacent gas-sensitive materials 13 to isolate the light path. If the gas-sensitive material 13 is as shown... Figure 1a As shown, if the partition plates 16 are arranged circumferentially within the annular chambers of the outer cylinder 11 and the inner cylinder 12, then the gas-sensitive material 13 will be arranged as follows: Figure 3 If arranged as shown, the partition plates 16 will be arranged axially at intervals in the annular cavities of the outer cylinder 11 and the inner cylinder 12.

[0082] Preferably, each gas-sensitive material 13 receives light matching its own intensity while effectively avoiding absorption by other gas-sensitive materials 13. Preferably, the isolation plate 16 is constructed as a light-blocking sheet made of opaque metal or ceramic material, and the isolation plate can be detachably installed on the inner cylinder 12.

[0083] The present invention uses light emitted by the lamp beads, which is roughly divided into visible light and ultraviolet light according to different wavelengths, which can significantly improve the gas-sensing performance of the gas-sensitive material 13.

[0084] Preferably, ultraviolet LEDs refer to LEDs with a light-emitting center wavelength below 400nm. However, sometimes LEDs with a light-emitting wavelength greater than 380nm are called near-ultraviolet LEDs, and those shorter than 300nm are called deep ultraviolet LEDs. Their power is less than 150mW, and their current is less than 120mA. Their luminous power can be adjusted according to the current, thus more easily meeting the requirements of different gas-sensitive materials 13 for different light radiation intensities.

[0085] Preferably, the visible light LED emission wavelength is between 400 and 760 nm. Different colored visible light LEDs, such as white, yellow, green, and red, can be selected based on the material properties, emitting light with different wavelengths. Its power is less than 50 mW, and its current is less than 20 mA. Its luminous power can be adjusted according to the current to meet the requirements of different gas-sensitive materials 13 for different light radiation intensities.

[0086] In this invention, there is a certain distance between the LED bead and the wall of the inner cylinder 12, so as to ensure that the heat of the LED bead can be dissipated in time, so as to avoid the situation that the heat is transferred to the inner wall and affects the working temperature of the gas-sensitive material 13.

[0087] This invention employs miniature LED beads, which are small in size, low in energy consumption, and long in life, thus improving the integration and energy efficiency of the entire sensor. Since the LED beads are located in the second chamber 22, and the gas-sensitive material 13 completely encapsulates them, the light emitted by the LED beads can be completely absorbed by the gas-sensitive material 13, further improving the utilization rate of the light.

[0088] Therefore, under the same enhancement effect, the LEDs in this device have the advantage of lower power consumption.

[0089] The quality of LED chips on the market varies greatly, and they are prone to damage during prolonged use, which can severely affect the lifespan of the entire sensor. Because the LED chips in this device are mounted on the lamp post rather than directly fixed to the inner cylinder 12, they can be replaced without altering other structural features, thereby extending the device's lifespan.

[0090] In one embodiment, the light-enhanced mixed gas detection device 100 further includes a plurality of sensing electrodes 15. Preferably, each gas-sensitive material 13 corresponds to one sensing electrode 15; in other words, both ends of each gas-sensitive material 13 are connected to the gold electrode ring of the sensing electrode 15, thereby enabling accurate measurement of the resistance change within the range of the gas-sensitive material 13.

[0091] Preferably, a gap of 1 to 2 mm is left between two adjacent gas-sensitive materials 13, thereby effectively avoiding contact between materials in different areas and helping the sensing electrode 15 to accurately measure the resistance change of its area.

[0092] This invention has the ability to simultaneously identify multiple gases in a mixed gas. It uses a pumping or diffusion method to allow the mixed gas to pass through the first chamber 21 of the light-enhanced sensor array, thereby causing different changes in the sensitive material 13 (the mixed gas and the sensitive material 13 undergo a gas-sensitive effect). Then, the sensor resistance change is identified by reading the conversion module (sensing electrode 15), and the central processing unit analyzes the gas concentration information through a pre-programmed procedure to realize data transmission and alarm functions.

[0093] Preferably, the light-enhanced mixed gas detection device 100 can be powered by a battery or wired connection. In addition, the device can also transmit data wirelessly or via wired connection.

[0094] According to a second aspect of the present invention, a testing method is provided, which utilizes a light-enhanced mixed gas detection device as described above, comprising the following steps:

[0095] First, multiple different gas-sensitive materials 13 are coated on the outer wall of the inner cylinder 12;

[0096] Then, the irradiation group 14 is fixed on the mounting base, and the response sensitivity of the sensor array is tested through the sensing electrode 15.

[0097] In this invention, the gas-sensitive material 13 must be dispersed in a suitable organic solvent before being coated on the outer wall of the inner cylinder 12, and then ground in an agate mortar to ensure that the gas-sensitive material 13 is uniformly dispersed in the organic solvent. Preferably, the organic solvent is, for example, ethanol, acetone, glycerol, or terpineol.

[0098] Preferably, the mass ratio of organic solvent to gas-sensitive material 13 is 0.1 to 10, with a 1:1 mass ratio being optimal. Specifically, if too much organic solvent is dissolved, the dispersion of gas-sensitive material 13 will be too thin, making it impossible to coat onto the substrate; if the amount of organic solvent is too small, the dispersion of gas-sensitive material 13 will be too thick, resulting in uneven material distribution on the substrate and further affecting the gas-sensing performance.

[0099] In this invention, the response performance of the gas-sensitive material 13 at room temperature can be improved by means of doping, loading, composite, and morphology control. Furthermore, screen printing, spraying, and other methods can be used in the coating process to further achieve precise control of the coating area.

[0100] Preferably, different types of organic solvents have different boiling points, with a preferred boiling point of 80-250℃. During the drying process, if the organic solvent with a low boiling point evaporates too quickly, it is prone to cracking; if the organic solvent with a high boiling point evaporates too slowly and is not easy to remove. Therefore, it is necessary to select the appropriate type and amount of organic solvent.

[0101] Example 1

[0102] Room temperature hydrogen-sensitive materials such as nano-ZnO, TiO2, and SnO2 can detect gases at room temperature. However, due to the low reactivity of semiconductor materials at room temperature, the response sensitivity and response speed of these materials are relatively poor.

[0103] Therefore, this invention employs ultraviolet / visible light irradiation to significantly enhance its performance. The main principle is roughly as follows: when photon energy matches the semiconductor bandgap, irradiation of the nano-gas-sensitive material 13 causes valence band electrons to be excited and cross the bandgap to reach the conduction band, forming photogenerated electron-hole pairs, thereby reducing the material resistance. Simultaneously, irradiation increases the adsorption capacity and concentration of adsorption centers on the semiconductor surface, improving chemisorption efficiency and thus enabling the gas-sensitive element to exhibit good sensitivity to the target gas at room temperature.

[0104] The mechanism of the entire gas-sensing process is described below:

[0105] First, oxygen molecules in the air adsorb onto the surface of the gas-sensitive material 13, forming adsorbed oxygen molecules. These adsorbed oxygen molecules then capture electrons from the gas-sensitive material 13 to form O2- ions, further forming an electron depletion layer. However, when the operating temperature is below 150℃, the adsorbed oxygen molecules mainly exist in the form of O2- ions, while when the operating temperature is above 150℃, the O2- ions will continue to capture electrons to form O- ions. Therefore, for SnO2, an n-type semiconductor, when it is placed in air, the number of charge carriers (electrons) decreases, and the resistance increases.

[0106] However, when the gas-sensitive material 13 comes into contact with a reducing gas (such as hydrogen sulfide, ammonia, etc.), the reducing gas is first adsorbed onto its surface, forming an adsorbed gas state. This adsorbed gas then reacts with O- ions, releasing electrons from the O- ions. The released electrons return to the gas-sensitive material 13, increasing the charge carriers and thus reducing its resistance.

[0107] Clearly, the entire process eventually reaches an adsorption-desorption equilibrium, at which point the resistance remains unchanged, thus reaching an equilibrium value. When the gas concentration in the environment changes, the resistance continues to change until a new equilibrium value is reached. The percentage change in resistance, i.e., the response value, is related to the carrier concentration of the gas-sensitive material 13 and the number of active sites on its surface. The time required to reach a new equilibrium state from the initial state, i.e., the response recovery time, is related to the material's specific surface area and operating temperature. Notably, the material's resistance affects its operating temperature.

[0108] Implementation 2

[0109] This embodiment will specifically describe the testing process of the light-enhanced mixed gas detection device with sensor array:

[0110] First, adjust the regulator according to the required input current, thereby adjusting the light radiation intensity of the lamp beads.

[0111] Then, after fixing the input current of the LED beads, place the sensor array in clean air. After the resistance measured by the sensing electrode 15 stabilizes, record the resistance R0 at this time.

[0112] Then, a mixed gas (i.e., a target gas of a certain concentration) is injected into the first chamber 21 through a porous grid. When the mixed gas comes into contact with the gas-sensitive material 13 to perform the gas-sensitive effect, the resistance will change. After the resistance measured by the sensing electrode 15 stabilizes, the resistance R1 at this time is recorded.

[0113] At that time, calculations will be performed using formulas. The response sensitivity of the sensor can then be obtained, and the response sensitivity of the entire sensor array can be further obtained.

[0114] Preferably, the response time t90 is the time required for the resistance to change by 90% |R0-R1| from R0. Subsequently, by inputting the response sensitivity of the sensors in different regions into the intelligent identification algorithm, the type of mixed gas can be quickly and accurately identified.

[0115] Example 3

[0116] This embodiment provides several comparative examples that differ from this device.

[0117] Firstly, when the LED beads are turned off during testing, the performance of the gas-sensitive material 13 is not improved. Therefore, the gas sensing process between the mixed gas and the gas-sensitive material 13 cannot be accelerated, and the response performance of the sensor array is significantly reduced.

[0118] Secondly, the porous grid lacks a waterproof and breathable membrane, which will affect the response performance of the sensor array during the test due to humidity.

[0119] Thirdly, the outer cylinder 11 adopts a transparent structure, and the response performance of the sensor array will be affected by ambient light, which will further lead to inaccurate response sensitivity data of the tested sensor array.

[0120] Fourth, using an external light source to illuminate the LEDs instead of the LEDs would require more power consumption to achieve the same sensing effect.

[0121] Example 4

[0122] Figure 4An embodiment of the light-enhanced mixed gas detection device 100 according to the present invention is illustrated schematically.

[0123] Combination Figure 4 In one embodiment shown, the device may consist of only one set of testing equipment, including coating a gas-sensitive material 13 on the outer wall of the inner cylinder 12, arranging a set of sensing electrodes 15 on both sides of the gas-sensitive material 13, and arranging a set of LEDs in the second chamber 22. In this way, the response sensitivity of the sensor array can be obtained by testing a single gas.

[0124] In this implementation, gas enters the first chamber 21 through the porous grid at the top and comes into contact with different gas-sensitive materials 13 in sequence to achieve a gas-sensitive effect, thereby causing a change in the resistance of the gas-sensitive materials 13, which is then recorded by the sensing electrode 15 and converted into an electrical signal. The concentration information is then analyzed by the algorithm pre-built in the processor for post-processing and transmission.

[0125] Combination Figure 3 As shown in one embodiment, this device can be equipped with multiple sets of testing devices, thereby enabling simultaneous detection of various gases. Specifically, it includes multiple layers of spaced gas-sensitive materials 13 coated on the outer wall of the inner cylinder 12, sensing electrodes 15 disposed on both sides of each gas-sensitive material 13, and multiple sets of LEDs disposed within the second chamber 22, wherein each LED corresponds to one gas-sensitive material 13.

[0126] In this embodiment, all LED beads can use LED chips of the same color, or LED chips of different colors (i.e., different emission wavelengths) can be selected according to the characteristics of different gas-sensitive materials 13.

[0127] Preferably, if lamp chips with different emission wavelengths are used, an isolation plate 16 needs to be provided between two adjacent lamp chips to block the light path. At the same time, the isolation plate 16 should be constructed as a light-blocking sheet made of opaque metal or ceramic material, and the isolation plate can be detachably installed on the inner cylinder 12.

[0128] In this implementation, the mixed gas enters the first chamber 21 through the porous grid at the top and comes into contact with different gas-sensitive materials 13 in sequence to achieve a gas-sensitive effect, thereby causing a change in the resistance of the gas-sensitive materials 13, which is then recorded by the sensing electrode 15 and converted into an electrical signal. The concentration information is then analyzed by the algorithm pre-built by the processor for post-processing and transmission.

[0129] Example 5

[0130] Figure 5 An embodiment of the light-enhanced mixed gas detection device 100 according to the present invention is illustrated schematically.

[0131] In this embodiment, depending on the characteristics of the gas-sensitive material 13, an optional temperature control system (adding a metal heating wire 17) can be installed to regulate the working temperature, or the material can be briefly regenerated at high temperatures.

[0132] Example 6

[0133] This embodiment will specifically describe the effect of the light-enhanced mixed gas detection device with sensor array:

[0134] The above preparation and testing procedures are adopted.

[0135] like Figure 6 As shown, a SnO2 gas sensor was prepared using a 1:1 solvent coating and a white monochromatic LED, following the aforementioned testing procedure. Tests were conducted three times each under both illuminated and non-illuminated conditions. The response value increased from approximately 40% to 80%, and the response speed also improved.

[0136] Compared with existing technologies, the advantages of this invention are:

[0137] Firstly, the sensor array in this invention can simultaneously arrange multiple sets of gas-sensitive materials 13 to have the ability to simultaneously identify multiple gases in a mixed gas.

[0138] Preferably, the device uses a pumping or diffusion method to allow the mixed gas to pass through the first chamber 21 of the sensor array, thereby causing different changes in the sensitive material 13 (the mixed gas and the sensitive material 13 undergo a gas-sensitive effect), and then the sensor electrode 15 detects the change in sensor resistance. The central processing unit then analyzes the gas concentration information through a pre-programmed procedure to realize data transmission and alarm functions.

[0139] Secondly, this invention employs miniature LED beads, which are small in size, low in energy consumption, and long in life, thus improving the integration and energy efficiency of the entire sensor. Since the LED beads are located in the second chamber 22, and the gas-sensitive material 13 completely encapsulates them, the light generated by the LED beads is completely absorbed by the gas-sensitive material 13, further improving the utilization rate of the light. Therefore, under the same enhancement effect, the LED beads in this device have the advantage of lower power consumption.

[0140] Furthermore, the lamp beads in this invention can be made of the same color wick, or different colors (i.e., different emission wavelengths) wicks can be selected according to the characteristics of different gas-sensitive materials 13, and different lamp beads can also be independently controlled to open and close.

[0141] Furthermore, due to the inconsistent quality of LED chips on the market, they are prone to damage during prolonged use, which can severely impact the lifespan of the entire sensor. Therefore, this device mounts the LED chips on the lamp post rather than directly fixing them to the inner cylinder 12. This allows for replacement without altering other structural features, thereby extending the device's lifespan.

[0142] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art can easily make changes or modifications within the scope of the present invention, and such changes or modifications should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A light-enhanced mixed gas detection device, comprising: Outer cylinder (11), and The sensor array includes an inner cylinder (12) concentrically arranged within the outer cylinder (11), and a sensor group disposed on the outer wall of the inner cylinder (12). The outer cylinder (11) and the inner cylinder (12) form a first chamber (21) that allows the flow of mixed gas. The sensing group includes a plurality of gas-sensitive materials (13) disposed on the inner wall of the inner cylinder (12) and used to contact the gas.

2. The light-enhanced mixed gas detection device according to claim 1, characterized in that, The gas-sensitive material (13) is a hydrogen-sensitive material, and the gas-sensitive material (13) includes at least two of nano ZnO, TiO2 and SnO2.

3. The light-enhanced mixed gas detection device according to claim 2, characterized in that, The inner cylinder (12) has a second chamber (22) for placing the irradiation group (14), and the light emitted by the irradiation group (14) can accelerate the gas-sensing process between the gas-sensitive material (13) and the mixed gas.

4. The light-enhanced mixed gas detection device according to claim 3, characterized in that, The outer cylinder (11) is made of opaque material, and the inner cylinder (12) is made of transparent material.

5. The light-enhanced mixed gas detection device according to claim 4, characterized in that, The illumination group (14) includes lamp posts arranged longitudinally and a plurality of lamp beads arranged at intervals along the axial direction of the lamp posts. The sensor array also includes mounting bases disposed at both ends of the inner cylinder (12) and connected to the lamp post, as well as an adjuster for the lamp beads.

6. The light-enhanced mixed gas detection device according to claim 5, characterized in that, Multiple gas-sensitive materials (13) are arranged at intervals along the circumference or along the axial direction on the inner wall of the inner cylinder (12).

7. The light-enhanced mixed gas detection device according to claim 6, characterized in that, The lamp beads contain wicks of the same color.

8. The light-enhanced mixed gas detection device according to claim 6, characterized in that, The lamp bead is located within the range of the gas-sensitive material (13) in the axial or circumferential direction, and the lamp bead is provided with a variety of different colored lamp cores that are compatible with the gas-sensitive material (13).

9. The light-enhanced mixed gas detection device according to claim 8, characterized in that, An isolation plate (16) for blocking the light path is provided between two adjacent gas-sensitive materials (13), and the isolation plate (16) is fixed on the inner cylinder (12).

10. The light-enhanced mixed gas detection device according to claim 7 or 8, characterized in that, The light-enhanced mixed gas detection device also includes multiple sensing electrodes (15) respectively connected to both ends of the gas-sensitive material (13) for recording resistance changes.

11. A testing method utilizing the light-enhanced mixed gas detection device according to any one of claims 1 to 10, comprising the following steps: S1. Coat the outer wall of the inner cylinder (12) with multiple different gas-sensitive materials (13); S2. Fix the irradiation group (14) on the mounting base and test the response sensitivity of the sensor array through the sensing electrode (15).

12. The method for detecting mixed gases according to claim 11, characterized in that, Before coating, the gas-sensitive material (13) and organic solvent need to be put into a mortar and ground thoroughly.

13. The method for detecting mixed gases according to claim 11, characterized in that, Step S2 also includes a test step: First, adjust the light radiation intensity of the lamp bead through the regulator. After the resistance measured by the sensing electrode (15) stabilizes, record the resistance R0 at this time. Then, a mixed gas is injected into the first chamber (21), and the mixed gas comes into contact with the gas-sensitive material (13) to perform a gas-sensitive effect. After the measured resistance of the sensing electrode (15) stabilizes, the resistance R1 at this time is recorded. Finally, the response sensitivity of the sensor array is obtained, i.e.

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