Humidity sensing system

Abstract

The invention discloses a humidity sensing system. The interior of a humidity measuring part is hollow to form a measuring cavity; the sensing function part is arranged between the humidity measuring part and the temperature measuring part and connects the humidity measuring part with the temperature measuring part, a thermopile is arranged in the sensing function part, a first optical receiver is arranged in the humidity measuring part, and a second optical receiver is arranged in the temperature measuring part; the end, away from the sensing function part, of the humidity measuring part is provided with an infrared light source inlet, the light beam movement direction introduced by the infrared light source inlet faces the sensing function part, the end, away from the sensing function part, of the temperature measuring part is provided with an infrared light source inlet, and the light beam movement direction introduced by the infrared light source inlet faces the sensing function part. A sensing layer is arranged on the surface, facing the humidity measuring part and the temperature measuring part, of the thermopile. According to the sensing system, the temperature and the humidity of air are simultaneously measured by adopting a single sensor device, so that measurement deviation caused by position difference when a plurality of independent sensors are used is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and in particular to a humidity sensing system. Background Art

[0002] Accurate measurement of air temperature and humidity is crucial in environmental monitoring. Traditional humidity measurement techniques primarily rely on point-type humidity sensors, such as capacitive relative humidity (RH) sensors. However, existing temperature and humidity measurement solutions have significant shortcomings. The most common approach is to combine independent temperature sensors (such as thermocouples and thermistors) with humidity sensors (such as capacitive RH sensors). This multi-sensor approach faces two core issues: first, poor spatial consistency. Because the two sensors may be physically located in different locations, the environmental parameters they measure may vary locally, resulting in an inaccurate reflection of the temperature and humidity conditions at the same point. Second, temporal asynchrony. Different sensor types have varying response speeds and sampling frequencies, making it difficult to ensure precise temporal matching of temperature and humidity data. This is particularly critical in scenarios requiring dynamic analysis of temperature and humidity interactions, such as meteorological research and precision environmental control. Existing multi-sensor systems require separate wiring, installation, and commissioning for each sensor, increasing system complexity and cost, and the probability of error. Signals from different sensors may experience time delays and accuracy deviations, requiring complex algorithms for data fusion and correction, making data processing more complex. Summary of the Invention

[0003] The embodiment of the present invention provides a humidity sensing system, which aims to solve the problem that the temperature and humidity sensor sensing system in the prior art methods has too single function.

[0004] The embodiment of the present invention discloses a humidity sensing system for simultaneously measuring air temperature and air humidity. The sensing system includes a multifunctional sensor based on double-sided sensing of a thermopile chip, an amplifier circuit, an analog-to-digital converter, and a central measurement controller. The multifunctional sensor is connected to the central measurement controller via the amplifier circuit and the analog-to-digital converter. The central measurement controller is connected to a computer system. The multifunctional sensor includes a humidity measurement unit, a temperature measurement unit, and a sensing function unit. The humidity measurement unit is hollow inside to form a measurement cavity. The sensing function unit is arranged between the humidity measurement unit and the temperature measurement unit and connects the humidity measurement unit to the temperature measurement unit. A thermopile is provided, a first optical receiver is provided in the humidity measuring part, and a second optical receiver is provided in the temperature measuring part; an infrared light source inlet is provided at one end of the humidity measuring part away from the sensing function part, and a light beam introduced by the infrared light source inlet moves in a direction toward the sensing function part; a plurality of air inlets are provided on the side wall of the cavity of the humidity measuring part; an infrared light source inlet is provided at one end of the temperature measuring part away from the sensing function part, and a light beam introduced by the infrared light source inlet moves in a direction toward the sensing function part; the interior of the temperature measuring part is hollow to form a measuring cavity, and the measuring cavity of the temperature measuring part is a closed cavity; a sensing layer is provided on the surface of the thermopile facing the humidity measuring part and on the surface of the temperature measuring part.

[0005] Furthermore, a first thermopile and a second thermopile are arranged in the sensing function part, the first thermopile is connected to the light signal emitted by the infrared light source received by the humidity measurement part and forms a dynamic humidity measurement channel in the measurement cavity of the humidity measurement part, and the second thermopile is connected to the light signal emitted by the infrared light source received by the humidity measurement part and forms a reference humidity measurement channel in the measurement cavity of the humidity measurement part.

[0006] Furthermore, the second optical receiver adopts an infrared lens.

[0007] Furthermore, the air inlet is arranged on the cavity wall surfaces on both sides of the measuring cavity, and the air inlet is provided in plurality, wherein one of the air inlets is arranged opposite to another of the air inlets.

[0008] Furthermore, the light source provided in the sensing function unit adopts infrared light with high modulation characteristics.

[0009] Furthermore, the thermopile includes a plurality of thermocouples, and the plurality of thermocouples in the thermopile are sequentially connected in series.

[0010] Furthermore, the center wavelength of the second optical receiver corresponding to the first thermopile is consistent with the center wavelength of the strong absorption band in the infrared absorption spectrum of water molecules, and the center wavelength of the second optical receiver corresponding to the second thermopile is consistent with the center wavelength of the weak absorption band in the infrared absorption spectrum of water molecules.

[0011] Furthermore, the multifunctional sensor superimposes the obtained temperature measurement signal and water vapor concentration signal to generate a thermopile response signal, which is then sent to the amplifier circuit through the same output channel. The thermopile response signal is processed by the central measurement controller and the result is output to the computer system.

[0012] The above-mentioned sensor sensing system achieves spatial consistency. By using a single sensor device to simultaneously measure air temperature and humidity, it avoids measurement deviations that may be caused by position differences when using multiple independent sensors. The present invention ensures that temperature and humidity measurements are performed at the same spatial point, thereby obtaining more accurate and representative environmental parameter data. Secondly, temporal consistency is guaranteed. Since the temperature and humidity signals are collected by the same sensor at the same time, this ensures strict temporal synchronization between the two. This enables the sensor to provide accurate time-matched data, effectively avoiding analysis errors that may be introduced due to asynchronous sampling times of different sensors. The invention significantly reduces system complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0014] Figure 1 A schematic diagram of the functional operation of a multifunctional sensor based on double-sided sensing of a thermopile chip provided by an embodiment of the present invention;

[0015] Figure 2 Another schematic diagram of the functional operation of a multifunctional sensor based on double-sided sensing of a thermopile chip provided by an embodiment of the present invention;

[0016] Figure 3 A schematic diagram of the working principle of the humidity sensing system provided in an embodiment of the present invention;

[0017] Figure 4 Another schematic diagram of the functional operation of the multifunctional sensor based on double-sided sensing of the thermopile chip provided by an embodiment of the present invention;

[0018] Figure 5 A schematic diagram showing the effect of the working process of the humidity sensing system provided by an embodiment of the present invention;

[0019] Figure 6 A schematic diagram of another working process of the humidity sensing system provided by an embodiment of the present invention;

[0020] Figure 7 A schematic diagram showing another working process of the humidity sensing system provided by an embodiment of the present invention;

[0021] Figure 8 This is a schematic diagram of another working process of the humidity sensing system provided by an embodiment of the present invention.

[0022] Figure Number:

[0023] 1. Sensing function unit; 2. First optical receiver; 3. Second optical receiver; 4. Humidity measurement unit; 5. Temperature measurement unit; 6. Thermopile; 61. First thermopile; 62. Second thermopile; 7. Air inlet. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0026] It should also be understood that the terms used in the present specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0027] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0028] like Figures 1 to 4As shown, a humidity sensing system provided in this embodiment is used for simultaneous measurement of air temperature and air humidity. The sensing system includes a multifunctional sensor based on double-sided sensing of a thermopile chip, an amplifier circuit, an analog-to-digital converter, and a central measurement controller. The multifunctional sensor is connected to the central measurement controller via the amplifier circuit and the analog-to-digital converter, and the central measurement controller is connected to the computer system. The multifunctional sensor includes a humidity measuring part 4, a temperature measuring part 5, and a sensing function part 1. The humidity measuring part 4 is hollow inside to form a measurement cavity; the sensing function part 1 is arranged between the humidity measuring part 4 and the temperature measuring part 5 and connects the humidity measuring part 4 to the temperature measuring part 5. A sensor is provided inside the sensing function part 1. A thermopile 6 is provided, a first optical receiver 2 is arranged in the humidity measuring part 4, and a second optical receiver 3 is arranged in the temperature measuring part 5; an infrared light source inlet is provided at the end of the humidity measuring part 4 away from the sensing function part 1, and the movement direction of the light beam introduced by the infrared light source inlet is toward the sensing function part 1, a plurality of air inlets 7 are provided on the side wall of the cavity of the humidity measuring part 4, an infrared light source inlet is provided at the end of the temperature measuring part 5 away from the sensing function part 1, and the movement direction of the light beam introduced by the infrared light source inlet is toward the sensing function part 1, the interior of the temperature measuring part 5 is hollow to form a measuring cavity, and the measuring cavity of the temperature measuring part 5 is a closed cavity; a sensing layer is provided on the surface of the thermopile 6 facing the humidity measuring part 4 and the temperature measuring part 5.

[0029] In actual use, the multifunctional sensor comprises a humidity measurement unit 4, a temperature measurement unit 5, and a sensing unit 1. The humidity measurement unit 4 has a hollow interior, forming a measurement cavity. A first optical receiver 2 is located within the cavity, with an infrared light inlet facing the sensing unit 1 to receive ambient thermal radiation. The cavity's sidewalls feature multiple air inlets 7. The temperature measurement unit 5 has a hollow interior, forming a closed measurement cavity. A second optical receiver 3 is located within the temperature measurement unit 5, with an infrared light inlet facing the sensing unit 1 to receive ambient thermal radiation. The sensing unit 1, located between the humidity measurement unit 4 and the temperature measurement unit 5, houses a thermopile 6 with sensing layers applied to both surfaces. An amplifier circuit amplifies the sensor output signal. An analog-to-digital converter converts the amplified signal into a format suitable for processing by a central measurement controller. The central measurement controller processes the signal and connects it to a computer system for data analysis and display. Conventional thermopile chips are typically thin-film structures, with both surfaces capable of receiving and responding to radiation energy. However, conventional NDIR gas detection sensors and infrared temperature sensors typically use only one surface of the thermopile 6 as a receiving surface. One surface of the thermopile 6 serves as a receiver for the NDIR water vapor detection module, detecting water vapor concentration. The other surface of the thermopile 6 serves as a receiver for the infrared temperature measurement module, measuring ambient temperature. The principle of the NDIR gas sensor is based on the absorption characteristics of gas molecules to infrared light of a specific wavelength, specifically according to the Lambert-Beer law: I = I0e -αcL, where (I) is the projected light intensity, (I0) is the incident light intensity, (α) is the gas absorption coefficient, (c) is the water vapor concentration, and (L) is the optical path. The NDIR gas sensor consists of an infrared light inlet (preferably a highly modulated MEMS light source) that can introduce ambient thermal radiation, an air chamber, a filter, a thermopile 6, and other components. The light source periodically emits infrared radiation in a pulse-modulated manner. When the infrared radiation passes through the air chamber, water vapor (water molecules in a gaseous state) absorbs part of the energy. The filter extracts the characteristic wavelength portion (such as 2.8μm or 6.5μm) of the transmitted energy that matches the water vapor absorption, and the thermopile chip is used to detect the radiation energy. When the infrared light passes through the air chamber, the water molecules in the gaseous state absorb the infrared light in the wavelength band that matches the vibration frequency of their molecules, resulting in a decrease in the intensity of the transmitted light. By detecting the radiation that is absorbed and irradiated to the receiving surface of the thermopile chip, the concentration of the gas to be measured can be calculated. The temperature measurement part 5 uses the other surface of the thermopile 6 to receive infrared radiation. The temperature measurement unit 5 has a closed measurement cavity housing a MEMS light source and a second optical receiver 3. Infrared radiation from the light beam introduced into the measurement cavity is received by a thermopile 6, and the ambient temperature is calculated by measuring the radiation energy. The humidity measurement unit 4 receives infrared light from the infrared light source. This light signal, transmitted through the measurement cavity (air entering through the air inlet 7), is absorbed by water vapor at specific wavelengths, reducing the intensity of the transmitted light. A filter extracts the characteristic wavelength, and one surface of the thermopile 6 receives and detects the radiation energy. Water vapor concentration is calculated using the Lambert-Beer law. The light signal from the infrared light source, received by the humidity measurement unit 4, transmits infrared light through the closed measurement cavity. The other surface of the thermopile 6 receives the infrared radiation, and the ambient temperature is calculated based on the radiation energy. The signal output by the thermopile 6 is amplified by an amplifier circuit, converted to a digital signal by an analog-to-digital converter, and processed by a central measurement controller. This signal is then connected to a computer system for data analysis and display. Leveraging the dual-sided nature of the thermopile chip, the dual functions of humidity and temperature measurement are achieved, improving the sensor's integration and efficiency. Able to measure air temperature and humidity simultaneously, providing more comprehensive environmental parameters.

[0030] The signal collected by the sensor of the present invention is composed of two superposition signals, one of which represents the ambient temperature and the other represents the NDIR gas concentration. Figure 5 The figure below shows the light source modulation signal and response. The NDIR gas concentration signal is a pulse signal characterized by a positive correlation between gas concentration and the rate of decrease in the signal's peak-to-peak value. That is, the higher the gas concentration, the greater the decrease in the peak-to-peak value. The ambient temperature signal is a DC signal whose intensity is positively correlated with the ambient temperature. The higher the temperature, the greater the signal intensity.

[0031] In summary, high-precision humidity and temperature measurements are achieved through NDIR technology and the high sensitivity of the thermopile 6. The multifunctional sensor is compact in design and suitable for integration into various devices and systems. Add filtering and shielding design to reduce the impact of ambient light and other interference on measurement accuracy. Optimize the light source and circuit design to reduce system power consumption, making it suitable for battery-powered application scenarios. Consider expanding the measurement function of other gases or parameters to increase the versatility of the sensor. The technical solution provided in this embodiment realizes the simultaneous measurement of air temperature and humidity by innovatively utilizing the double-sided characteristics of the thermopile chip. This solution not only improves the integration and efficiency of the sensor, but also realizes high-precision measurement through NDIR technology and the high sensitivity of the thermopile 6. The system is compact in design and suitable for integration into various devices and systems, and has broad application prospects.

[0032] Furthermore, a first thermopile 61 and a second thermopile 62 are arranged in the sensing function part 1. The first thermopile 61 is connected to the light signal emitted by the infrared light source received by the humidity measuring part 4 and forms a dynamic humidity measurement channel in the measuring cavity of the humidity measuring part 4. The second thermopile 62 is connected to the light signal emitted by the infrared light source received by the humidity measuring part 4 and forms a reference humidity measurement channel in the measuring cavity of the humidity measuring part 4.

[0033] Furthermore, preferably, the first optical receiver 2 uses a narrowband filter with a central wavelength of 2.5-6.5 μm, and the second optical receiver 3 uses a bandpass filter with a central wavelength of 8-14 μm.

[0034] Furthermore, in a more preferred embodiment, the second optical receiver 3 in the above embodiment may optionally adopt an infrared lens.

[0035] Specifically, the multifunctional sensor sensing system has been further optimized in the design of the sensing function part 1. A first thermopile 61 and a second thermopile 62 are provided in the sensing function part 1, both of which are connected to the optical signal emitted by the infrared light source received by the humidity measurement part 4, and form a dynamic humidity measurement channel and a reference humidity measurement channel respectively in the measurement cavity of the temperature measurement part 5. This design aims to improve the stability and accuracy of temperature measurement through comparative measurement. In terms of the humidity measurement module, the first optical receiver 2 in its core NDIR module adopts a narrowband filter with a central wavelength of 2.5-6.5um. This wavelength range includes the main absorption characteristic band of water vapor (such as 2.8um or 6.5um), which can effectively capture the infrared radiation energy after water vapor absorption and direct it to the A surface of the thermopile 61 and the thermopile 62 for detection. At the same time, the second optical receiver 3 of the humidity measurement module (used for the temperature measurement module) adopts a bandpass filter with a central wavelength of 8-14um. This wavelength band (atmospheric window) typically matches the main peak region of ambient thermal radiation (blackbody radiation) and is relatively resistant to interference from absorption peaks of gases such as water vapor, making it ideal for measuring ambient temperature. In a more preferred embodiment, to improve the efficiency and accuracy of infrared radiation collection, the second optical receiver 3 (temperature measurement module) can optionally employ an infrared lens to focus the radiated energy onto the B-side of the thermopile 6. By integrating these specific design details, the sensor solution further clarifies the functions and characteristics of each optical component and optimizes the optical path design, potentially improving the performance and reliability of humidity measurement (through precise selection of the water vapor absorption band) and temperature measurement (through the selection of the reference channel and atmospheric window bands, and the optional infrared lens). Combining the previously described core elements of the NDIR module (MEMS light source, high-reflectivity gas chamber, narrowband filter), the temperature measurement module (B-side of the thermopile 6, reference channel filter), signal superposition and separation processing, and dual-sided sensing of the thermopile 6, this solution forms an advanced sensing system with high functional integration and comprehensive measurement parameters. Specifically, the humidity measurement module is divided into two parts: the first is the NDIR module, which uses a MEMS light source with high modulation performance to meet specific modulation frequency, depth, and duty cycle requirements. The duty cycle is preferably low to accommodate the response characteristics of the thermopile 6. The gas chamber uses high-reflectivity materials or surface treatments (such as coatings) to enhance multiple internal reflections of infrared light, improving its interaction with water vapor and energy transfer efficiency. This module is equipped with a narrowband filter to select a wavelength that matches the water vapor absorption characteristics (such as 2.8μm or 6.5μm). A reference channel filter (such as 3.95μm) is also provided to eliminate interference from ambient gases and provide a calibration signal. When infrared light passes through the gas chamber, water vapor absorbs some of the energy. One surface (surface A) of the thermopile 6 receives the absorbed radiation and outputs a periodic pulse signal related to the water vapor concentration. The peak-to-peak decrease in the signal is positively correlated with the gas concentration.The other part of the humidity measurement, namely the temperature measurement module, uses the other surface (B side) of the thermopile 6 to receive ambient thermal radiation. By using long-pass or band-pass filters, the module can eliminate the interference of common gases in the environment (such as water vapor and carbon dioxide) on temperature measurement, and a reference channel of the same band can be set to improve accuracy. Both the A side and the B side of the thermopile 6 can operate based on the Seebeck effect, generating a temperature difference voltage after absorbing infrared radiation. This voltage signal is positively correlated with the ambient temperature, and the ambient temperature can be calculated through measurement and calibration. In addition, such as. Figure 4 As shown in the figure, the thermopile array technology mentioned in the solution shows the possibility of further expansion. By integrating multiple detection units with infrared optical systems, it can not only measure the ambient temperature distribution, but also obtain the spatial relative humidity distribution by combining the NDIR function. This is of great value in fields such as environmental monitoring and climate control. Taking a 16*16 thermopile array device as an example, by partitioning the measurement space and using infrared lenses to correspond one-to-one with the pixels of the thermopile array, the temperature distribution in the measurement environment can be obtained, as shown in the figure below. Figure 6 As shown: the lighter the color, the higher the temperature, and the darker the color, the lower the temperature. When the absolute humidity of the space has been measured, the relative humidity distribution of the measured space can be calculated based on the temperature distribution and absolute humidity of the space. Under the same absolute humidity, the relative humidity is negatively correlated with the space temperature. The higher the temperature, the lower the relative humidity. Figure 7 As shown: The signal collected by the sensor is the superposition of the NDIR gas concentration signal (pulse) and the ambient temperature signal (DC). According to the superposition principle, subsequent processing will separate and demodulate the two signals. The sampling frequency is set in accordance with the Nyquist sampling theorem and must be greater than twice the highest frequency of the signal to ensure undistorted recovery. This solution uses MEMS light source, high reflectivity gas chamber, narrowband filter (corresponding to surface A in thermopile 6), long-pass / bandpass filter (corresponding to surface B in thermopile 6) and signal processing technology to not only improve the integration and efficiency of the sensor, but also achieve high-precision and comprehensive monitoring of environmental parameters. Its compact design makes it easy to integrate into various devices and systems, and has broad application prospects.

[0036] Further, preferably, the air inlet 7 is provided on the cavity wall surfaces on both sides of the measuring cavity, and a plurality of air inlets 7 are provided, wherein one air inlet 7 is provided opposite to another air inlet 7 .

[0037] Furthermore, the light source provided in the sensor function unit 1 uses infrared light with high modulation characteristics.

[0038] Specifically, the multifunctional sensor sensing system is further optimized in detail design to improve performance and stability. In the NDIR module of the humidity measurement module, multiple air inlets 7 are symmetrically arranged on the cavity walls on both sides of the measurement cavity, and one air inlet 7 is arranged opposite to the other. This layout design is intended to ensure that the air to be measured can enter the measurement cavity evenly and quickly and fully contact the infrared light, thereby improving the accuracy and response speed of the water vapor concentration measurement. However, if the air inlets 7 are not arranged oppositely, the fluidity of the gas in the cavity can be enhanced, so that the humidity in the cavity remains uniform. Therefore, the air inlet 7 is set in an open manner. At the same time, the light source provided in the sensing function part 1 adopts an infrared light source with high modulation characteristics. This ensures that the emitted infrared light can meet the specific modulation frequency, depth and duty cycle requirements, which is crucial for distinguishing the water vapor concentration signal from the ambient temperature signal through subsequent signal processing. In combination with what was mentioned before, the NDIR part of the humidity measurement module uses a MEMS light source (as one of the specific implementations of high modulation characteristics). The infrared light it emits undergoes multiple reflections in the high-reflectivity air chamber, is selected by a narrow-band filter with a central wavelength of 2.5-6.5um (the first optical receiver 2), and is irradiated onto the A surface of the thermopile 6 for water vapor concentration detection. As for the temperature measurement module, the first thermopile 61 and the second thermopile 62 in the sensing function part 1 are respectively connected to the light signals emitted by the infrared light source received by the humidity measurement part 4, forming a dynamic humidity measurement channel and a reference humidity measurement channel in the measurement cavity to improve the accuracy of temperature measurement. The second optical receiver 3 uses a bandpass filter with a central wavelength of 8-14um (or an infrared lens in the preferred embodiment is combined with the filter) to measure the ambient humidity. All these signals, including the NDIR gas concentration signal (pulse) and the ambient humidity signal (DC), such as Figure 8 The figure shows the superposition and separation method. The signals are superimposed in the same output channel, and then subsequently separated, demodulated, and processed according to the superposition principle and Nyquist sampling theorem. Through these meticulous designs, the sensor not only achieves simultaneous, high-precision measurement of air temperature and humidity, but also enhances measurement stability and reliability through optimized air inlet layout and light source selection. Its compact design makes it easy to integrate into various devices and systems, promising broad application prospects.

[0039] Furthermore, the thermopile 6 includes a plurality of thermocouples, and the plurality of thermocouples in the thermopile 6 are sequentially connected in series.

[0040] Furthermore, the center wavelength of the second optical receiver 3 corresponding to the first thermopile 61 is consistent with the center wavelength of the strong absorption band in the infrared absorption spectrum of water molecules, and the center wavelength of the second optical receiver 3 corresponding to the second thermopile 62 is consistent with the center wavelength of the weak absorption band in the infrared absorption spectrum of water molecules.

[0041] Specifically, the multifunctional sensor sensing system has been further refined in terms of core sensing elements and optical design. The thermopile 6 is a key photoelectric conversion element, and its internal structure includes multiple thermocouples, which are arranged in series to enhance signal output and improve the sensitivity and response speed of the sensor. In the NDIR part of the humidity measurement module, the selection of the optical receiver is more accurately matched to the absorption characteristics of water vapor. Specifically, the center wavelength of the optical receiver corresponding to the first thermopile 61 (i.e., the receiver for humidity measurement, whose center wavelength is a narrowband filter of 2.5-6.5um) is set to be consistent with the center wavelength of the strong absorption band in the infrared absorption spectrum of water molecules (e.g., 2.8um or 6.5um). This enables the sensor to capture the absorption signal of water vapor to infrared light to the maximum extent, thereby improving the sensitivity of humidity measurement. In contrast, the center wavelength of the optical receiver corresponding to the second thermopile 62 (i.e., the receiver for temperature measurement, whose center wavelength is a bandpass filter of 8-14um) is set to be consistent with the center wavelength of the weak absorption band in the infrared absorption spectrum of water molecules. This design may be used to achieve more accurate temperature compensation or serve as a reference signal for temperature measurement, especially in the presence of water vapor interference. Selecting a weak absorption band can reduce the impact of water vapor on temperature measurement and improve the accuracy of temperature measurement. Combining the core elements described previously, such as the symmetrical setting of the air inlet 7, the high-modulation infrared light source, the dynamic and reference humidity measurement channels, the signal superposition and separation processing, and the double-sided sensing of the thermopile 6, this solution forms an advanced sensing system with high functional integration, comprehensive measurement parameters, and optimization for specific gas absorption characteristics. Through these meticulous designs, the sensor not only achieves synchronous and high-precision measurement of air temperature and humidity, but also enhances the stability and reliability of the measurement through the optimized optical path design and thermopile 6 structure. Its compact design makes it easy to integrate into various devices and systems, and has broad application prospects.

[0042] Furthermore, the multifunctional sensor superimposes the obtained temperature measurement signal and water vapor concentration signal to generate the thermopile 6 response signal and sends it to the amplifier circuit through the same output channel. The thermopile 6 response signal is processed by the central measurement controller and the result is output to the computer system. The signal output can be taken as follows: Figure 3 The two output schemes shown provide analog output and / or digital output for the sensor according to the actual usage scenario.

[0043] The present invention discloses a humidity sensing system for simultaneously measuring air temperature and air humidity. The sensing system includes a multifunctional sensor based on double-sided sensing of a thermopile chip, an amplifier circuit, an analog-to-digital converter, and a central measurement controller. The multifunctional sensor is connected to the central measurement controller via the amplifier circuit and the analog-to-digital converter, and the central measurement controller is connected to a computer system. The multifunctional sensor includes a humidity measuring part 4, a temperature measuring part 5, and a sensing function part 1. The humidity measuring part 4 is hollow inside to form a measurement cavity. The sensing function part 1 is arranged between the humidity measuring part 4 and the temperature measuring part 5 and connects the humidity measuring part 4 to the temperature measuring part 5. A thermocouple is arranged inside the sensing function part 1. The thermopile 6 includes a first optical receiver 2 disposed within the humidity measurement unit 4, and a second optical receiver 3 disposed within the temperature measurement unit 5. An infrared light source inlet is disposed at the end of the humidity measurement unit 4 remote from the sensing unit 1, directing the light beam introduced by the infrared light source inlet toward the sensing unit 1. Multiple air inlets 7 are disposed on the sidewalls of the cavity of the humidity measurement unit 4. An infrared light source inlet is disposed at the end of the temperature measurement unit 5 remote from the sensing unit 1, directing the light beam introduced by the infrared light source inlet toward the sensing unit 1. The interior of the temperature measurement unit 5 is hollow, forming a closed measurement cavity. Sensing layers are disposed on the surfaces of the thermopile 6 facing the humidity measurement unit 4 and the temperature measurement unit 5. This sensor control system offers significant advantages. First, it achieves spatial consistency. By using a single sensor device to simultaneously measure air temperature and humidity, it avoids measurement errors that may arise from positional differences when using multiple independent sensors. The present invention ensures that temperature and humidity measurements are performed at the same spatial point, thereby obtaining more accurate and representative environmental parameter data. Second, it ensures temporal consistency. Since the temperature and humidity signals are collected by the same sensor at the same time, strict temporal synchronization between the two is ensured. This enables the sensor to provide precise time-matched data, effectively avoiding analytical errors that may be introduced due to the asynchronous sampling time of different sensors. The invention significantly reduces the complexity of the system. At the hardware level, it reduces the number of sensors required and the corresponding connection lines, making the hardware structure of the entire sensing system simpler. At the data processing level, since the temperature and humidity signals originate from the same source, the data itself has natural consistency. Therefore, there is no need to consider data synchronization and calibration issues between different sensors during processing, which greatly simplifies the data processing process. In summary, through its unique single-sensor design, it not only improves the accuracy and synchronization of measurements, but also significantly simplifies the system composition and data processing. It is an efficient, reliable and easy-to-integrate environmental parameter measurement solution.

[0044] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A humidity sensing system for simultaneously measuring air temperature and humidity, comprising a multifunctional sensor based on a thermopile chip with double-sided sensing, an amplifier circuit, an analog-to-digital converter, and a central measurement controller, wherein the multifunctional sensor is connected to the central measurement controller via the amplifier circuit and the analog-to-digital converter, and the central measurement controller is connected to a computer system, characterized in that: The multifunctional sensor comprises: A humidity measuring part, a temperature measuring part and a sensing function part, wherein the humidity measuring part is hollow inside to form a measuring cavity; The sensing function unit is provided between the humidity measuring unit and the temperature measuring unit and connects the humidity measuring unit and the temperature measuring unit, wherein a thermopile is provided in the sensing function unit, a first optical receiver is provided in the humidity measuring unit, and a second optical receiver is provided in the temperature measuring unit; An infrared light source inlet is provided at one end of the humidity measuring portion away from the sensing function portion, and the direction of movement of the light beam introduced by the infrared light source inlet is toward the sensing function portion. A plurality of air inlets are provided on the side wall of the cavity of the humidity measuring portion. An infrared light source inlet is provided at one end of the temperature measuring portion away from the sensing function portion, and the direction of movement of the light beam introduced by the infrared light source inlet is toward the sensing function portion. The interior of the temperature measuring portion is hollow to form a measuring cavity, and the measuring cavity of the temperature measuring portion is a closed cavity. A sensing layer is provided on the surface of the thermopile facing the humidity measuring part and the temperature measuring part.

2. The humidity sensing system according to claim 1, characterized in that A first thermopile and a second thermopile are provided in the sensing function part. The first thermopile is connected to the light signal emitted by the infrared light source received by the humidity measurement part and forms a dynamic humidity measurement channel in the measurement cavity of the humidity measurement part. The second thermopile is connected to the light signal emitted by the infrared light source received by the humidity measurement part and forms a reference humidity measurement channel in the measurement cavity of the humidity measurement part.

3. The humidity sensing system according to claim 1, wherein: The second optical receiver uses an infrared lens.

4. The humidity sensing system according to claim 1, wherein: The air inlet is arranged on the cavity wall surfaces on both sides of the measuring cavity. There are multiple air inlets, and one of the air inlets is arranged opposite to the other air inlet.

5. The humidity sensing system according to claim 1, wherein: The light source provided in the sensing function unit adopts infrared light with high modulation characteristics.

6. The humidity sensing system according to claim 1, wherein: The thermopile includes a plurality of thermocouples, and the plurality of thermocouples in the thermopile are sequentially connected in series.

7. The humidity sensing system according to claim 2, wherein: The central wavelength of the second optical receiver corresponding to the first thermopile is consistent with the central wavelength in the strong absorption band in the infrared absorption spectrum of water molecules, and the central wavelength of the second optical receiver corresponding to the second thermopile is consistent with the central wavelength in the weak absorption band in the infrared absorption spectrum of water molecules.

8. The humidity sensing system according to claim 1, wherein: The multifunctional sensor superimposes the obtained temperature measurement signal and water vapor concentration signal to generate a thermopile response signal, which is then sent to the amplifier circuit through the same output channel. The thermopile response signal is processed by the central measurement controller and the result is output to the computer system.

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