A consumable-free air allergen detection device and method based on the fusion of ultraviolet fluorescence and scattered light

Abstract

The present invention relates to a consumable-free air allergen detection device and method based on the fusion of ultraviolet fluorescence and scattered light. The device comprises an airway system, an optical detection module, a self-cleaning electrode, and an auxiliary module. The airway system comprises a spiral airway. The optical detection module comprises an ultraviolet fluorescence unit and a dual-wavelength scattering unit. The ultraviolet fluorescence unit comprises an ultraviolet LED and a 340nm bandpass filter. The dual-wavelength scattering unit comprises a 650nm laser, an 850nm VCSEL, and a scattering detector. The auxiliary module comprises a temperature and humidity sensor. The spiral airway is located at the central axis of the device. The ultraviolet LED is inclined at an 8° angle to the central axis of the spiral airway. The 340nm bandpass filter is located directly opposite the ultraviolet LED and coaxial with it. The 650nm laser is installed at a 15° forward angle on the spiral airway. The 850nm VCSEL is installed at a 90° lateral angle on the spiral airway. The scattering detector integrates a 15° forward channel and a 90° lateral channel. The present invention enables small-volume, consumable-free, and high-precision real-time detection of airborne proteins and allergens.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental detection, and in particular relates to a consumable-free air allergen detection device and method based on the fusion of ultraviolet fluorescence and scattered light. Background Art

[0002] Airborne allergens (such as pollen, dust mite proteins, and pet dander) are the main triggers of allergic diseases. Real-time and accurate detection of their concentrations is crucial for indoor air quality control. Current detection technologies face the following challenges:

[0003] 1. Traditional biological detection method (taking ELISA as an example)

[0004] Technical principle: Based on antigen-antibody specific reaction, protein allergens are quantitatively analyzed by enzyme-linked colorimetric development.

[0005] Technical defects:

[0006] Dependence on consumables: Each test requires the consumption of reagent kits (such as antibody chips and color developers), and the cost of a single sample is greater than 50 yuan, which cannot meet the needs of long-term real-time monitoring.

[0007] Time lag: It takes 2-4 hours from sampling to result output, which cannot cope with sudden pollution scenarios (such as pollen outbreaks).

[0008] Equipment volume: Requires incubator, enzyme reader and other peripherals, volume > 500cm 3 , for laboratory environments only.

[0009] 2. Laser scattering particle detection technology

[0010] Technical principle: Using Mie scattering theory, the particle size distribution is inverted through the scattered light intensity of a single wavelength (such as 850nm).

[0011] Technical defects:

[0012] Inability to distinguish between biological and non-biological particles: Only the physical size of particles (e.g., 0.5-10 μm) can be detected, and compositional differences (e.g., pollen protein versus industrial dust) cannot be identified. For example, a pollen grain with a diameter of 5 μm will have almost identical scattering signals to a quartz grain of the same size.

[0013] Small particle detection blind spot: The detection sensitivity for nano-scale allergens (such as dust mite metabolic proteins) less than 0.5μm is insufficient, and the scattered light intensity decays exponentially with decreasing particle size.

[0014] 3. Traditional fluorescence detection technology

[0015] Technical principle: A high-power ultraviolet mercury lamp (>10W) is used to excite protein fluorescence (such as tryptophan residues emit 340nm fluorescence under 280nm excitation).

[0016] Technical defects:

[0017] Volume and power consumption: The UV light source needs to be equipped with a heat dissipation device and a filter system. The volume of the whole machine should be greater than 2000cm 3 , power consumption > 10W, which is difficult to integrate into a small air purifier.

[0018] Lifespan and stability: The lifespan of a mercury lamp is less than 1000 hours, and the lamp decays over time, causing a decrease in detection accuracy (annual drift > 15%), requiring regular calibration.

[0019] Ambient light interference: The ultraviolet component in natural light (such as sunlight) can easily cause background noise and requires additional light shielding design.

[0020] In summary, the common bottlenecks of existing technologies include:

[0021] 1) The contradiction between miniaturization and portability: Traditional detection equipment is limited by the size of optical modules (such as large UV lamps and discrete detectors) and is difficult to embed into household appliances (such as air conditioners and car purifiers).

[0022] 2) Insufficient detection specificity: A single physical test (scattered light) cannot distinguish the composition of particles, and a single chemical test (fluorescence) lacks particle size information, resulting in a high misjudgment rate (such as misidentifying fluorescently labeled non-biological particles as allergens).

[0023] 3) High maintenance cost: Operations such as replacement of consumables (ELISA), calibration of light sources (fluorescent lamps), and cleaning of gas paths (scattering sensors) increase the cost of use, making it difficult to achieve the goal of "maintenance-free". Summary of the Invention

[0024] The purpose of the present invention is to provide a consumable-free air allergen detection device and method based on the fusion of ultraviolet fluorescence and scattered light, so as to achieve small-volume, consumable-free, high-precision real-time detection of proteins and allergens in the air.

[0025] The present invention provides a consumable-free air allergen detection device based on the fusion of ultraviolet fluorescence and scattered light, comprising an air path system, an optical detection module, a self-cleaning electrode and an auxiliary module;

[0026] The gas path system includes a spiral gas path; the optical detection module includes an ultraviolet fluorescence unit and a dual-wavelength scattering unit; the ultraviolet fluorescence unit includes an ultraviolet LED and a 340nm bandpass filter; the dual-wavelength scattering unit includes a 650nm laser, an 850nm VCSEL, and a scattering detector; the auxiliary module includes a temperature and humidity sensor;

[0027] The spiral air path is located on the central axis of the detection device and is in a counterclockwise spiral shape when viewed from above; the air flow inlet of the spiral air path is located at the top of the detection device and is connected to an external sampling pump via a silicone tube; the air flow outlet of the spiral air path is located at the bottom of the detection device and is used to connect to the return air outlet of the air purifier through a guide plate;

[0028] The UV LED is inclined at an angle of 8° to the central axis of the spiral gas path, and its output light beam is focused to the center of the spiral gas path by a collimating lens; the 340nm bandpass filter is located directly opposite the UV LED and coaxial with the UV LED;

[0029] The 650nm laser is installed at a 15° forward angle to the spiral gas path relative to the airflow direction, with its emitted light beam forming an angle of 15° with the axis of the spiral gas path and introduced into the detection area via a fiber coupler; the 850nm VCSEL is installed at a 90° lateral angle to the spiral gas path;

[0030] The scattering detector is located on the opposite side of the 650nm laser, integrating a forward 15° channel and a lateral 90° channel, limiting the receiving angle by an aperture, and converting the output signal into a voltage signal through a transimpedance amplifier;

[0031] The self-cleaning electrodes are two pairs of interlaced copper electrodes, which are embedded in the inner wall of the spiral gas path in a comb shape, and the electrode plane is parallel to the axis of the spiral gas path;

[0032] The temperature and humidity sensor is integrated into the air flow outlet section of the spiral air path.

[0033] Furthermore, the inner wall of the spiral gas path is made of anodized aluminum alloy and coated with polytetrafluoroethylene to reduce particle adsorption.

[0034] Furthermore, the ultraviolet LED is fixed on the aluminum heat sink by means of thermally conductive adhesive, and the 340 nm bandpass filter is fixed by means of a spring buckle.

[0035] Furthermore, the excitation wavelength range of the ultraviolet LED is 270-280 nm.

[0036] Furthermore, the 850nm VCSEL is fixed on the PCB board using surface mounting technology, with a modulation frequency of 1kHz.

[0037] Furthermore, the positive electrode of the self-cleaning electrode is connected to a high-voltage pulse generator, the negative electrode is grounded, and the pulse signal is transmitted through an insulated wire, which is covered with an electromagnetic shielding layer.

[0038] Furthermore, the temperature and humidity sensors adopt thermocouples and capacitive humidity sensors.

[0039] The present invention also provides an air allergen detection method using the device, comprising the following steps:

[0040] Step 1, dual-wavelength scattering signal acquisition and particle size classification, includes:

[0041] Scattered light excitation:

[0042] 1) a 650 nm laser (201) and an 850 nm VCSEL synchronously emit pulsed light with a pulse width of 10 μs and a frequency of 1 kHz, irradiating the particles to be tested in the spiral gas path at a forward angle of 15° and a side angle of 90° respectively;

[0043] 2) The scattering detector synchronously collects two scattered light intensity signals I 650 and I 850 , converted into digital signal through transimpedance amplification and 16-bit ADC;

[0044] Particle size calculation and particle classification:

[0045] 1) Based on Mie scattering theory, the particle size D is calculated by the scattering intensity ratio p , Where ρ is the particle density, and the biological particle density is 1.3 g / cm 3 The density of non-biological particles is 2.5 g / cm 3 ;

[0046] 2) Particle size classification threshold:

[0047] Small particles of 0.5-5 μm are detected with a 650 nm signal;

[0048] Large particles of 5-10 μm are detected with a signal at 850 nm;

[0049] Step 2, UV fluorescence signal acquisition and protein concentration calculation, includes:

[0050] Fluorescence excitation and time-resolved detection:

[0051] 1) A 275nm UV LED with a 10μs pulse width and 1kHz frequency excites the protein in the particles, emitting a 340nm fluorescence signal;

[0052] 2) Using time-resolved fluorescence technology, the fluorescence signal is detected during the 1-10 μs interval after the 275 nm UV LED is turned off to suppress ambient light interference;

[0053] Fluorescence signal processing:

[0054] 1) Extract the fluorescence AC signal through a lock-in amplifier and filter out DC noise;

[0055] 2) Fitting the fluorescence decay curve based on the double exponential decay model: Wherein, the characteristic time constants of biological particles are τ1 = 8-15 μs and τ2 = 50-100 μs, which are used to distinguish biological from non-biological fluorescent substances; t is the particle residence time; A1 represents the contribution of the first fluorescent component to the total fluorescence intensity at time t = 0, and A2 represents the contribution of the second fluorescent component to the total fluorescence intensity at time t = 0;

[0056] Concentration inversion:

[0057] Fluorescence intensity peak I peak The calibration curve was converted to protein concentration C, and the calibration function was:

[0058] Step 3, temperature and humidity compensation and signal calibration, includes:

[0059] Environmental parameter collection:

[0060] The ambient temperature T (unit: °C) and relative humidity RH (unit: %) are collected in real time through the temperature and humidity sensor;

[0061] Drift compensation calculation:

[0062] Fluorescence signal temperature and humidity drift correction formula: V corr =V raw -[0.15×(RH-50%)+0.02×(T-25°C)], where V raw is the original fluorescence voltage signal; V corr It is the compensated signal and is used for subsequent concentration calculation;

[0063] Step 4: AI fusion decision and result output, including:

[0064] Feature vector construction:

[0065] Input 7-dimensional features to the SVM classification model:

[0066] Particle size distribution parameters: small particle ratio, large particle ratio, average particle size;

[0067] Fluorescence characteristics: Peak intensity I peak , biological particle characteristic time constant τ1;

[0068] Environmental parameters: temperature T, relative humidity RH;

[0069] Classification and concentration calculation:

[0070] 1) The SVM classification model learns the characteristics of biological particles through training data and outputs the classification confidence. A threshold of >95% is used to determine whether the particle is a biological allergen.

[0071] 2) The particle size and fluorescence concentration calculation results are integrated, and the detected allergen content per unit volume is converted into the concentration in the actual environment in combination with the air flow rate, and the allergen type and mass concentration are finally output; the air flow rate is 0.8 L / min.

[0072] Furthermore, the method also includes: the spiral gas path performs a self-cleaning action in combination with the self-cleaning electrode to reduce particle deposition without manual cleaning.

[0073] Through the above scheme, the consumable-free air allergen detection device and method based on the fusion of ultraviolet fluorescence and scattered light have the following technical effects:

[0074] 1) Miniaturized optical design:

[0075] 275nm UV LED (power < 50mW) is used to replace traditional mercury lamps, reducing the volume by 90% and extending the life to more than 8 years.

[0076] The integrated dual-wavelength scattering module (650nm laser + 850nm VCSEL) enables joint analysis of particle size and composition through multi-angle detection.

[0077] 2) No consumables, self-maintenance:

[0078] The spiral gas path (helix angle 15°±0.5°) combined with self-cleaning electrodes (2kV pulse ionization) reduces particle deposition and eliminates the need for manual cleaning.

[0079] Time-resolved fluorescence technology (10μs pulse excitation + intermittent detection) is used to suppress ambient light interference and avoid the background noise problem of traditional fluorescence sensors.

[0080] 3) Multimodal fusion detection:

[0081] The scattering intensity ratio of 650nm / 850nm is used to distinguish the particle density (the density of biological particles is 1.3g / cm 3 vs non-biological 2.5g / cm 3 ), combined with fluorescence signals to achieve dual identification of "physical size + chemical composition".

[0082] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] Figure 1 This is a schematic structural diagram of a consumables-free air allergen detection device based on the fusion of ultraviolet fluorescence and scattered light according to the present invention;

[0084] Figure 2A two-dimensional cross-sectional view of the consumables-free air allergen detection device based on the fusion of ultraviolet fluorescence and scattered light of the present invention;

[0085] Figure 3 is a flow chart of the detection method of the present invention;

[0086] Figure 4 This is a protein concentration-fluorescence signal calibration curve in one embodiment of the present invention. DETAILED DESCRIPTION

[0087] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0088] Ginseng Figure 1 、 Figure 2 As shown, this embodiment provides a consumable-free air allergen detection device based on the fusion of ultraviolet fluorescence and scattered light. It is a micro sensor that integrates ultraviolet fluorescence excitation and dual-wavelength laser scattering. It is used to detect the concentration of protein allergens (such as pollen and dust mite protein) and particulate matter in the air in real time. It is suitable for environmental appliances such as air purifiers and air conditioners. The specific structure is as follows:

[0089] 1. Gas system

[0090] Spiral gas path 301:

[0091] Position: The central axis of the device, in a counterclockwise spiral shape (from a top view), with an inner diameter of 3mm, a spiral lead of 5mm, and a total of 3 turns.

[0092] Connection relationship: The inlet is located at the top of the device and is connected to the external sampling pump through a 2mm inner diameter silicone tube (airtightness level: 10 -6 mbar·L / s); the outlet is located at the bottom of the device and connects to the air purifier return air outlet through a guide plate.

[0093] Material: Anodized aluminum alloy inner wall (thickness 0.5mm), covered with polytetrafluoroethylene coating (surface energy <18mN / m) to reduce particle adsorption.

[0094] 2. Optical detection module

[0095] 1) Ultraviolet fluorescence unit:

[0096] UV LED (275nm): Installed on the left side of the gas path, at an 8° angle to the central axis of the gas path (to avoid direct exposure to the detector), fixed to an aluminum heat sink (thermal resistance <5K / W) using thermal adhesive; the output beam is focused to the center of the gas path by a collimating lens (focal length 10mm), with a spot diameter of 0.8mm.

[0097] 340nm bandpass filter 102: Located directly opposite the UV LED (on the right side of the gas path), coaxial with the LED light path, fixed by a spring buckle, and the filter surface is parallel to the gas path axis.

[0098] 2) Dual-wavelength scattering unit (distinguishing biological and non-biological particles by Mie scattering intensity ratio):

[0099] 650nm laser 201: installed in the gas path at an angle of 15° (relative to the gas flow direction), with the emitted light beam at an angle of 15° to the gas path axis, and introduced into the detection area through a fiber optic coupler (coupling efficiency > 90%).

[0100] 850nm VCSEL202: Installed at 90° to the side of the gas path (perpendicular to the gas path axis in the horizontal plane), fixed to the PCB board using surface mount technology (SMT), modulation frequency 1kHz.

[0101] Scatter detector 203: integrated dual-channel photodiode (forward 15° channel, side 90° channel), located on the opposite side of the 650nm laser, with an aperture (aperture 0.5mm) limiting the receiving angle, and the output signal is sent to a transimpedance amplifier (gain 10 5 V / A) is converted into a voltage signal.

[0102] 3. Self-cleaning electrode 302

[0103] 1) Structure: Two pairs of staggered copper electrodes (electrode width 0.2mm, spacing 0.3mm) are embedded in the inner wall of the gas path in a "comb" shape, with the electrode plane parallel to the gas path axis.

[0104] 2) Connection relationship: The positive pole is connected to the high-voltage pulse generator (2kV, 1Hz), the negative pole is grounded, and the pulse signal is transmitted through the insulated wire (withstand voltage 3kV), and the wire is covered with an electromagnetic shielding layer (weaving density >90%).

[0105] 3) Self-cleaning effect:

[0106] The spiral gas path (helix angle 15°±0.5°) combined with the self-cleaning electrode (2kV pulse ionization) reduces particle deposition and eliminates the need for manual cleaning.

[0107] Electrode pulse frequency: 1Hz;

[0108] Particle removal rate: >99.5% (0.5-10μm particles);

[0109] Life test: 5000 hours of continuous operation without performance degradation.

[0110] 4. Auxiliary modules

[0111] Temperature and humidity sensor 401: integrated in the gas outlet section, 10mm away from the end of the gas line, using a capacitive humidity sensor (accuracy ±2% RH) and a thermocouple (accuracy ±0.5°C), through I 2 C bus communicates with the main control chip.

[0112] The parameters of each component are shown in Table 1 and Table 2.

[0113] Table 1 Parameter table (I)

[0114]

[0115] Table 2 Parameter table (II)

[0116]

[0117]

[0118] Collaborative design of optical and gas paths:

[0119] Angle between the optical path and the air path: The angle between the ultraviolet excitation light and the airflow direction is 8°, ensuring that the fluorescence excitation path length of the particles in the detection area is greater than 2mm (optical path utilization rate >80%); the scattered light detection direction is 15° (forward) and 90° (side) to the airflow direction, corresponding to the optimal detection angles for Mie scattering (small particles) and Rayleigh scattering (large particles), respectively.

[0120] Gas circuit sealing: The optical window and gas circuit interface are sealed with O-ring (material: fluororubber, temperature resistance -40℃~200℃), leakage rate <5×10 -7 m 3 / s.

[0121] Orthogonal optical path layout: UV excitation light and scattered light are inclined at an 8° angle to avoid direct exposure to the detector; dual-wavelength scattered light is converged by a parabolic reflector (focal length 20mm) to improve detection sensitivity.

[0122] Stray light suppression:

[0123] The interior of the air chamber is blackened (reflectivity < 0.1%).

[0124] The optical window is coated with multi-layer anti-reflection coating: 275nm transmittance>95%; 650nm / 850nm reflectivity>99%.

[0125] Gas path optimization design:

[0126] 1) Spiral gas path dynamics

[0127] Air flow velocity: 0.8 m / s (Reynolds number Re=1500, laminar flow state).

[0128] Particle residence time:

[0129] Right now:

[0130]

[0131] Where, L is the length of the air path (m); D is the diameter of the spiral (m); N is the number of spiral turns; and v is the air velocity (m / s).

[0132] Theoretical deposition rate: <0.1% (calculated based on Stokes' law).

[0133] 2) Working principle of self-cleaning electrode

[0134] High-voltage pulses ionize the air to produce O3, which decomposes organic pollutants.

[0135] Ion wind speed: 2 m / s (electrode spacing 0.3 mm, electric field strength 6.67 kV / cm).

[0136] Ion wind speed formula:

[0137]

[0138] Where, E: electric field strength (V / m); μ: ion mobility (2.0×10 -4 m2 / (V·s)); α: air pressure correction coefficient (0.01Pa -1 ); p: ambient air pressure (Pa).

[0139] Integrated packaging technology:

[0140] 1) Miniaturized design

[0141] Total volume: 25mm 3 (30mm×15mm×5mm); Weight: <15g (aluminum alloy frame + PC shell).

[0142] 2) EMI protection

[0143] Detector shield: μ metal coating, attenuation> 80dB (100kHz-1GHz).

[0144] Power supply filtering: π-type LC filter (cut-off frequency 10kHz).

[0145] The key performance comparison is shown in Table 3.

[0146] Table 3 Key performance comparison

[0147] index Device of the present invention Traditional fluorescence sensors volume <![CDATA[25mm 3 ]]> <![CDATA[>1000mm 3 ]]> Power consumption 0.3W (standby) / 0.8W (working) ＞5W Detection limit (protein) <![CDATA[0.08μg / m 3 ]]> <![CDATA[0.5μg / m 3 ]]> Response time <2 seconds >30 seconds life >8 years (no consumables) 1-2 years (consumables need to be replaced)

[0148] Through the above arrangement, the device realizes the compact integration of "gas path-light path-circuit path" and3 It can complete particle sampling, fluorescence excitation, dual-wavelength scattering detection and self-cleaning functions within the volume, meeting the stringent installation requirements of portable equipment.

[0149] Ginseng Figure 3 As shown, the detection method process is as follows:

[0150] Step 1: Dual-wavelength scattering signal acquisition and particle size classification

[0151] Scattered light excitation:

[0152] 1) The 650 nm semiconductor laser 201 and the 850 nm vertical cavity surface emitting laser (VCSEL) synchronously emit pulsed light (pulse width 10 μs, frequency 1 kHz), irradiating the particles to be measured in the spiral gas path 301 at a forward angle of 15° (Mie scattering sensitivity angle) and a side angle of 90° (Rayleigh scattering sensitivity angle), respectively.

[0153] 2) The scattering detector 203 synchronously collects two scattered light intensity signals I 650 and I 850 , after transimpedance amplification (gain 10 5 ,V / A) and 16-bit ADC to convert into digital signal.

[0154] Particle size calculation and particle classification:

[0155] 1) Based on Mie scattering theory, the particle size D is calculated by the scattering intensity ratio p : Where ρ is the particle density, and the biological particle density ρ = 1.3 g / cm 3 , density of non-biological particles ρ = 2.5 g / cm 3 .

[0156] 2) Particle size classification threshold:

[0157] Small particles (0.5-5μm): The 650nm signal is dominant (Mie scattering). 650nm is used to detect particles 0.5-5μm (Mie scattering).

[0158] Large particles (5-10 μm): 850 nm is dominant (Rayleigh scattering). 850 nm is used to detect particles 5-10 μm (Rayleigh scattering).

[0159] Step 2: UV fluorescence signal acquisition and protein concentration calculation

[0160] Fluorescence excitation and time-resolved detection:

[0161] 1) A 275 nm UV LED (pulse width 10 μs, frequency 1 kHz) excites the protein (tryptophan residues) in the particles, emitting a 340 nm fluorescent signal.

[0162] 2) Use time-resolved fluorescence technology: detect the fluorescence signal during the 1-10μs interval after the LED is turned off to suppress ambient light interference (such as the ultraviolet component in sunlight).

[0163] Fluorescence signal processing:

[0164] 1) A lock-in amplifier (reference frequency 1 kHz, quality factor Q = 50) was used to extract the fluorescence AC signal and filter out the DC noise.

[0165] 2) Fitting the fluorescence decay curve based on the double exponential decay model: The characteristic time constants of biological particles, τ1 = 8-15 μs and τ2 = 50-100 μs, are used to distinguish biological from non-biological fluorescent substances. Here, t is the particle residence time; A1 represents the contribution of the first fluorescent component to the total fluorescence intensity at t = 0, and A2 represents the contribution of the second fluorescent component to the total fluorescence intensity at t = 0. Their magnitudes depend on factors such as the content of different fluorescent substances in the sample, the fluorescence efficiency, and the intensity of the excitation light. A higher content of a particular fluorescent substance in the sample may result in a larger corresponding A value, and its contribution to the total fluorescence intensity will also be greater.

[0166] In aeroallergen detection devices based on the fusion of ultraviolet fluorescence and scattered light, the fluorescence decay curve plays several important roles:

[0167] 1. Distinguishing between biological and non-biological particles: Different substances exhibit different fluorescence decay characteristics when stimulated. Biological particles (such as pollen and dust mite proteins) have specific fluorescence decay time constants, such as τ1 = 8-15μs and τ2 = 50-100μs. These time constants are obtained by fitting the fluorescence decay curve to determine whether the particle is of biological origin. If the detected fluorescence decay time constant is within the characteristic range for biological particles, it is likely a biological allergen; otherwise, it is likely a non-biological particle. This allows for the distinction between biological and non-biological particles, improving detection accuracy and specificity.

[0168] 2. Improved detection accuracy: Fluorescence decay curves provide more precise information when calculating protein concentration. Calculating protein concentration based solely on fluorescence intensity can be affected by various factors, while fluorescence decay curves comprehensively reflect the characteristics of fluorescent substances. By analyzing characteristics such as curve shape and decay rate, combined with calibration curves for concentration inversion, protein concentration can be determined more accurately, reducing errors. For example, for two samples with similar fluorescence intensity but different decay curves, the difference in protein content can be accurately distinguished, improving detection accuracy.

[0169] 3. Assisting in Determining Sample Characteristics: Fluorescence decay curves can also reflect the complexity and interactions of fluorescent substances within a sample. A complex decay pattern may indicate the presence of multiple fluorescent components interacting with each other, or a specific interaction between the fluorescent substance and its surroundings. This helps further understand sample characteristics, providing a reference for analyzing the composition and source of airborne allergens, and is crucial for in-depth research into indoor air quality and the causes of allergic reactions.

[0170] Concentration inversion:

[0171] Fluorescence intensity peak I peak The calibration curve (such as Figure 4 The calibration function is:

[0172] Step 3: Temperature and humidity compensation and signal calibration

[0173] Environmental parameter collection:

[0174] The temperature and humidity sensor 401 collects the ambient temperature T (unit: ° C.) and relative humidity RH (unit: %) in real time.

[0175] Drift compensation calculation:

[0176] Fluorescence signal temperature and humidity drift correction formula: V corr =V raw -[0.15×(RH-50%)+0.02×(T-25°C)]where V raw is the original fluorescence voltage signal, and the compensated signal V corr Used for subsequent concentration calculations.

[0177] Step 4: AI fusion decision and result output

[0178] Feature vector construction:

[0179] Input 7-dimensional features to the SVM classification model:

[0180] Particle size distribution parameters (3D): small particle ratio, large particle ratio, average particle size.

[0181] Fluorescence characteristics (2D): Peak intensity I peak , characteristic time constant τ1 of biological particles.

[0182] Environmental parameters (2D): temperature T, relative humidity RH.

[0183] Classification and concentration calculation:

[0184] 1) The SVM model learns the characteristics of biological particles through training data (including 10 common allergens, such as ragweed pollen and dust mite protein) and outputs the classification confidence (threshold > 95% is judged as a biological allergen).

[0185] 2) The particle size and fluorescence concentration calculation results are integrated and corrected with the air flow rate (0.8 L / min). The final output is the allergen type (such as "pollen" and "dust mite protein") and mass concentration (μg / m 3 ).

[0186] Combining the gas flow rate (0.8L / min) correction is an important step to ensure the accuracy of the test results, which mainly plays a role in the accuracy of concentration calculation, sample representativeness and compensation of detection errors.

[0187] 1. Accurately calculate the actual concentration: The detection device calculates the concentration of allergens by measuring fluorescence signals and scattered light signals, but these signals reflect the situation within a unit volume. The air flow rate (0.8L / min) provides volume information in a time dimension. For example, the volume of air passing through the air path over a certain period of time will vary due to different air flow rates. Combined with the air flow rate, the allergen content per unit volume detected can be converted into the concentration in the actual environment. Assuming that a certain amount of allergen is detected per unit volume at a certain moment, but the air flow rate is unknown, it is impossible to determine the overall concentration in the actual environment. However, when the air flow rate is known to be 0.8L / min, the total volume passing through the detection area during this period can be calculated based on the detection time, thereby accurately calculating the allergen concentration in the actual environment.

[0188] 2. Ensure sample representativeness: A stable airflow rate of 0.8 L / min ensures representative air samples entering the testing area. A stable flow rate means the same amount of air enters the testing area over a given period of time, allowing the detected allergen concentration to better reflect the true environmental conditions. Unstable airflow rates can result in excessive or insufficient air entering the testing area at certain times, leading to skewed test results and an inability to accurately represent the actual concentration in the environment. For example, excessive airflow may dilute the allergen concentration within the testing area, resulting in a low test result. Excessive airflow may lead to inaccurate test results due to insufficient sample volume.

[0189] 3. Compensating for errors during the detection process: During the detection process, errors may occur due to various factors, such as interference from the fluorescence signal and measurement errors in scattered light. Gas flow rate, as an accurately measurable parameter, can be used to compensate for these errors. By precisely controlling and measuring gas flow rate and combining it with other test data, algorithms can be used to correct test results. For example, when the detected fluorescence signal is subject to certain interference, the degree of this interference's impact on the concentration calculation can be determined based on the gas flow rate and other relevant parameters, and corresponding adjustments can be made, thereby improving the accuracy of the test results.

[0190] The comparison table of key technical parameters is shown in Table 4.

[0191] Table 4 Comparison of key technical parameters

[0192]

[0193] Through the above process, the device realizes a full closed-loop detection from particle sampling, multimodal signal acquisition to intelligent fusion analysis, with the characteristics of high precision, fast response and no consumables, and is suitable for real-time monitoring of allergens in complex environments.

[0194] Experimental verification:

[0195] 1. Calibration curve (refer to Figure 4 shown)

[0196] Curve characteristics:

[0197] Detection limit: 0.08 μg / m 3 (Signal-to-noise ratio = 3).

[0198] Linear range: 0.1-100 μg / mL 3 (R 2 =0.992.

[0199] Non-linearity: <5% (@100μg / m 3 ).

[0200] 1. Temperature and humidity compensation formula:

[0201] ΔV=0.15×(RH-50%)+0.02×(T-25℃)

[0202] Test data:

[0203] Humidity effect: For every 10% increase in RH, the signal shifts by +1.5mV.

[0204] Temperature effect: For every 10°C increase in temperature, the signal shifts by +0.2mV.

[0205] Compensation effect: When the temperature and humidity fluctuate by ±20%, the detection deviation is less than 2.3%.

[0206] Compared with the prior art, the present invention has the following technical effects:

[0207] 1) Miniaturized design: spiral gas path + staggered electrodes, volume < 25mm 3 .

[0208] 2) Consumable-free technology: Self-cleaning electrodes (pulse voltage 2kV) + UV LED lifespan >8 years. Traditional fluorescence sensors require consumable replacement.

[0209] 3) Multimodal detection: Dual-wavelength scattering + time-resolved fluorescence fusion. Accuracy in distinguishing between biological and non-biological particles is 98.7%.

[0210] 4) Time-resolved fluorescence technology: 10μs pulse excitation + intermittent detection suppresses ambient light interference and avoids the background noise problem of traditional fluorescence sensors.

[0211] The comparison with the existing technology is shown in Table 5.

[0212] Table 5 Comparison of existing technologies

[0213]

[0214]

[0215] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A consumable-free air allergen detection device based on the fusion of ultraviolet fluorescence and scattered light, characterized in that: Including gas path system, optical detection module, self-cleaning electrode and auxiliary module; The gas path system includes a spiral gas path; the optical detection module includes an ultraviolet fluorescence unit and a dual-wavelength scattering unit; the ultraviolet fluorescence unit includes an ultraviolet LED and a 340nm bandpass filter; the dual-wavelength scattering unit includes a 650nm laser, an 850nm VCSEL, and a scattering detector; the auxiliary module includes a temperature and humidity sensor; The spiral air path is located on the central axis of the detection device and is in a counterclockwise spiral shape when viewed from above; the air flow inlet of the spiral air path is located at the top of the detection device and is connected to an external sampling pump via a silicone tube; the air flow outlet of the spiral air path is located at the bottom of the detection device and is used to connect to the return air outlet of the air purifier through a guide plate; The UV LED is installed on the left side of the spiral gas path; the UV LED is inclined at an angle of 8° to the central axis of the spiral gas path, and its output light beam is focused to the center of the spiral gas path by a collimating lens; the 340nm bandpass filter is installed on the right side of the spiral gas path; the 340nm bandpass filter is located directly opposite the UV LED and is coaxial with the UV LED; The 650nm laser is installed at a 15° forward angle to the spiral gas path relative to the airflow direction, with its emitted light beam forming an angle of 15° with the axis of the spiral gas path and introduced into the detection area via a fiber coupler; the 850nm VCSEL is installed at a 90° lateral angle to the spiral gas path; The scattering detector is located on the opposite side of the 650nm laser, integrating a forward 15° channel and a lateral 90° channel, limiting the receiving angle by an aperture, and converting the output signal into a voltage signal through a transimpedance amplifier; The self-cleaning electrodes are two pairs of interlaced copper electrodes, which are embedded in the inner wall of the spiral gas path in a comb shape, and the electrode plane is parallel to the axis of the spiral gas path; The temperature and humidity sensor is integrated into the air flow outlet section of the spiral air path.

2. The consumable-free air allergen detection device based on the fusion of ultraviolet fluorescence and scattered light according to claim 1 is characterized in that: The inner wall of the spiral gas path is made of anodized aluminum alloy and coated with polytetrafluoroethylene to reduce particle adsorption.

3. The consumable-free air allergen detection device based on the fusion of ultraviolet fluorescence and scattered light according to claim 1 is characterized in that: The ultraviolet LED is fixed on the aluminum heat sink by thermal conductive adhesive, and the 340nm bandpass filter is fixed by a spring buckle.

4. The consumable-free air allergen detection device based on the fusion of ultraviolet fluorescence and scattered light according to claim 1 is characterized in that: The excitation wavelength range of the ultraviolet LED is 270-280 nm.

5. The consumable-free air allergen detection device based on the fusion of ultraviolet fluorescence and scattered light according to claim 1 is characterized in that: The 850nm VCSEL is fixed on the PCB board using surface mounting technology, and the modulation frequency is 1kHz.

6. The consumable-free air allergen detection device based on the fusion of ultraviolet fluorescence and scattered light according to claim 1 is characterized in that: The positive pole of the self-cleaning electrode is connected to a high-voltage pulse generator, and the negative pole is grounded. The pulse signal is transmitted through an insulated wire, and the wire is covered with an electromagnetic shielding layer.

7. The consumable-free air allergen detection device based on the fusion of ultraviolet fluorescence and scattered light according to claim 1 is characterized in that: The temperature and humidity sensor adopts a thermocouple and a capacitive humidity sensor.

8. A method for detecting air allergens using the device according to any one of claims 1 to 7, characterized in that: The steps include: Step 1, dual-wavelength scattering signal acquisition and particle size classification, includes: Scattered light excitation: 1) a 650 nm laser (201) and an 850 nm VCSEL synchronously emit pulsed light with a pulse width of 10 μs and a frequency of 1 kHz, irradiating the particles to be tested in the spiral gas path at a forward angle of 15° and a side angle of 90° respectively; 2) The scattering detector synchronously collects two scattered light intensity signals I 650 and I 850 , converted into digital signal through transimpedance amplification and 16-bit ADC; Particle size calculation and particle classification: 1) Based on Mie scattering theory, the particle size D is calculated by the scattering intensity ratio p , Where ρ is the particle density, and the biological particle density is 1.3 g / cm 3 The density of non-biological particles is 2.5 g / cm 3 ; 2) Particle size classification threshold: Small particles of 0.5-5 μm are detected with a 650 nm signal; Large particles of 5-10 μm are detected with a signal at 850 nm; Step 2, UV fluorescence signal acquisition and protein concentration calculation, includes: Fluorescence excitation and time-resolved detection: 1) A 275nm UV LED with a 10μs pulse width and 1kHz frequency excites the protein in the particles, emitting a 340nm fluorescence signal; 2) Using time-resolved fluorescence technology, the fluorescence signal is detected during the 1-10 μs interval after the 275 nm UV LED is turned off to suppress ambient light interference; Fluorescence signal processing: 1) Extract the fluorescence AC signal through a lock-in amplifier and filter out DC noise; 2) Fitting the fluorescence decay curve based on the double exponential decay model: Wherein, the characteristic time constants of biological particles are τ1 = 8-15 μs and τ2 = 50-100 μs, which are used to distinguish biological from non-biological fluorescent substances; t is the particle residence time; A1 represents the contribution of the first fluorescent component to the total fluorescence intensity at time t = 0, and A2 represents the contribution of the second fluorescent component to the total fluorescence intensity at time t = 0; Concentration inversion: Fluorescence intensity peak I peak The calibration curve was converted to protein concentration C, and the calibration function was: Step 3, temperature and humidity compensation and signal calibration, includes: Environmental parameter collection: The ambient temperature T (unit: °C) and relative humidity RH (unit: %) are collected in real time through the temperature and humidity sensor; Drift compensation calculation: Fluorescence signal temperature and humidity drift correction formula: V corr =V raw -[0.15×(RH-50%)+0.02×(T-25°C)], where V raw is the original fluorescence voltage signal; V corr It is the compensated signal and is used for subsequent concentration calculation; Step 4: AI fusion decision and result output, including: Feature vector construction: Input 7-dimensional features to the SVM classification model: Particle size distribution parameters: small particle ratio, large particle ratio, average particle size; Fluorescence characteristics: Peak intensity I peak , biological particle characteristic time constant τ1; Environmental parameters: temperature T, relative humidity RH; Classification and concentration calculation: 1) The SVM classification model learns the characteristics of biological particles through training data and outputs the classification confidence. A threshold of >95% is used to determine whether the particle is a biological allergen. 2) The particle size and fluorescence concentration calculation results are integrated, and the detected allergen content per unit volume is converted into the concentration in the actual environment in combination with the air flow rate, and the allergen type and mass concentration are finally output; the air flow rate is 0.8 L / min.

9. The method for detecting air allergens according to claim 8, wherein: Also includes: The spiral gas path combines with the self-cleaning electrode to perform a self-cleaning action to reduce particle deposition without the need for manual cleaning.

Images