A humidity sensing system

Abstract

The application discloses a humidity sensing system, a measuring cavity is formed in the inside of a humidity measuring part; a sensing function part is arranged between the humidity measuring part and a temperature measuring part and connects the humidity measuring part and the temperature measuring part, a thermoelectric pile 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; an infrared light source entrance is arranged at one end of the humidity measuring part away from the sensing function part, the infrared light source entrance is introduced to the sensing function part in the moving direction of a light beam, an infrared light source entrance is arranged at one end of the temperature measuring part away from the sensing function part, the infrared light source entrance is introduced to the sensing function part in the moving direction of a light beam, and a sensing layer is arranged on the surface of the thermoelectric pile facing the humidity measuring part and the temperature measuring part. The above-mentioned sensing system simultaneously measures the air temperature and humidity by using a single sensor device, and avoids the measurement deviation caused by the position difference when multiple independent sensors are used.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and more particularly to a humidity sensing system. Background Technology

[0002] In the field of environmental monitoring, accurate measurement of air temperature and humidity is crucial. Traditional humidity measurement techniques mainly rely on point-type humidity sensors, such as capacitive relative humidity (RH) sensors. However, existing temperature and humidity measurement schemes have significant shortcomings. The most common approach is to use a combination of independent temperature sensors (such as thermocouples and thermistors) and humidity sensors (such as capacitive RH sensors). This multi-sensor approach faces two core problems: First, poor spatial consistency. Because the two sensors may be physically located differently, the environmental parameters they measure may have local differences, making it impossible to accurately reflect the temperature and humidity conditions at the same point. Second, temporal asynchrony. Different types of sensors have different response speeds and sampling frequencies, making it difficult to ensure precise temporal matching of temperature and humidity data. This is particularly critical in scenarios that require dynamic analysis of the interaction between temperature and humidity (such as meteorological research and precision environmental control). Existing multi-sensor systems require separate wiring, installation, and debugging for each sensor, increasing system complexity and cost, as well as the probability of errors. Signals from different sensors may have time delays and accuracy deviations, requiring complex algorithms for data fusion and correction, increasing the difficulty of data processing. Summary of the Invention

[0003] This invention provides a humidity sensing system, which aims to solve the problem that the temperature and humidity sensor sensing systems in the prior art are too limited in function.

[0004] This invention discloses a humidity sensing system for simultaneously measuring air temperature and humidity. The sensing system includes a multifunctional sensor based on a thermopile chip with double-sided sensing, an amplifier circuit, an analog-to-digital converter (ADC), and a central measurement controller. The multifunctional sensor is connected to the central measurement controller via the amplifier circuit and the ADC. The central measurement controller is connected to a computer system. The multifunctional sensor includes a humidity measuring unit, a temperature measuring unit, and a sensing function unit. The humidity measuring unit has a hollow interior forming a measuring cavity. The sensing function unit is disposed between and connects the humidity measuring unit and the temperature measuring unit. A thermopile is provided. A first optical receiver is provided inside the humidity measuring section, and a second optical receiver is provided inside the temperature measuring section. An infrared light source inlet is provided at the end of the humidity measuring section away from the sensing function section. The light beam introduced by the infrared light source inlet moves towards the sensing function section. Multiple air inlets are provided on the cavity sidewall of the humidity measuring section. An infrared light source inlet is provided at the end of the temperature measuring section away from the sensing function section. The light beam introduced by the infrared light source inlet moves towards the sensing function section. The interior of the temperature measuring section is hollow to form a measuring cavity, which is a closed cavity. A sensing layer is provided on the surface of the thermopile facing both the humidity measuring section and the temperature measuring section.

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

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

[0007] Furthermore, the air inlets are disposed on the two cavity walls of the measuring cavity, and there are multiple air inlets, with one air inlet disposed opposite to another.

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

[0009] Furthermore, the thermopile includes multiple thermocouples, which are connected in series within the thermopile.

[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 amplification circuit through the same output channel. The thermopile response signal is processed by the central measurement controller, which outputs the result to the computer system.

[0012] The aforementioned sensor system achieves spatial consistency by simultaneously measuring air temperature and humidity using a single sensor device, avoiding measurement deviations that may occur due to location differences when using multiple independent sensors. This invention ensures that temperature and humidity measurements are taken at the same spatial point, resulting in more accurate and representative environmental parameter data. Secondly, it guarantees temporal consistency. Since the temperature and humidity signals are acquired by the same sensor at the same time, strict temporal synchronization is guaranteed. This allows the sensor to provide accurate time-matched data, effectively avoiding analytical errors that may be introduced by asynchronous sampling times of different sensors. This invention significantly reduces system complexity. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

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

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

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

[0017] Figure 4 This is another schematic diagram illustrating the functional operation of the multifunctional sensor based on thermopile chip double-sided sensing provided in an embodiment of the present invention.

[0018] Figure 5 This is a schematic diagram illustrating the working process of the humidity sensing system provided in an embodiment of the present invention.

[0019] Figure 6 This is a schematic diagram illustrating another process of the humidity sensing system provided in an embodiment of the present invention.

[0020] Figure 7 A schematic diagram illustrating another process of the humidity sensing system provided in this embodiment of the invention;

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

[0022] Icon labels:

[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 Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0026] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this 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 also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0028] like Figures 1 to 4As shown, this embodiment provides a humidity sensing system for simultaneously measuring air temperature and humidity. The sensing system includes 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. 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 measuring unit 4, a temperature measuring unit 5, and a sensing function unit 1. The humidity measuring unit 4 is hollow, forming a measuring cavity. The sensing function unit 1 is disposed between the humidity measuring unit 4 and the temperature measuring unit 5, connecting the humidity measuring unit 4 and the temperature measuring unit 5. The sensing function unit 1 contains... The thermopile 6 has a first optical receiver 2 installed inside the humidity measuring section 4 and a second optical receiver 3 installed inside the temperature measuring section 5. An infrared light source inlet is provided at the end of the humidity measuring section 4 away from the sensing function section 1, and the direction of the light beam introduced by the infrared light source inlet is towards the sensing function section 1. Multiple air inlets 7 are provided on the side wall of the cavity of the humidity measuring section 4. An infrared light source inlet is provided at the end of the temperature measuring section 5 away from the sensing function section 1, and the direction of the light beam introduced by the infrared light source inlet is towards the sensing function section 1. The interior of the temperature measuring section 5 is hollow to form a measuring cavity, and the measuring cavity of the temperature measuring section 5 is a closed cavity. Sensing layers are provided on the surfaces of the thermopile 6 facing the humidity measuring section 4 and the temperature measuring section 5.

[0029] In practical applications, the multifunctional sensor includes a humidity measurement unit 4, a temperature measurement unit 5, and a sensing function unit 1. The humidity measurement unit 4 is hollow, forming a measurement cavity, housing a first optical receiver 2, and has an infrared light inlet that allows ambient heat radiation to be introduced, facing the sensing function unit 1. Multiple air inlets 7 are located on the sidewalls of the cavity. The temperature measurement unit 5 is hollow, forming a closed measurement cavity, housing a second optical receiver 3, and has an infrared light inlet that allows ambient heat radiation to be introduced, facing the sensing function unit 1. The sensing function unit 1 is located between the humidity measurement unit 4 and the temperature measurement unit 5, housing a thermopile 6. Sensing layers are formed on both surfaces of the thermopile 6. An amplifier circuit amplifies the signal output by the sensor. 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 to a computer system for data analysis and display. Traditional thermopile chips are typically thin-film structures, with both surfaces capable of receiving radiant energy and generating a response. However, traditional NDIR gas detection sensors and infrared temperature sensors typically use only one surface of the thermopile 6 as the receiving surface. One surface of thermopile 6 serves as the receiver for the NDIR water vapor detection module, used to detect water vapor concentration. The other surface of thermopile 6 serves as the receiver for the infrared temperature measurement module, used to measure ambient temperature. The principle of the NDIR gas sensor is based on the absorption characteristics of gas molecules for specific wavelengths of infrared light, specifically according to the Lambert-Beer Law: I = I₀e⁻¹. -αcLWhere (I) is the transmitted 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 length. The NDIR gas sensor consists of an infrared light inlet (preferably a highly modulated MEMS light source) that can introduce ambient thermal radiation, a gas chamber, a filter, and a thermopile 6. The light source periodically emits infrared radiation in a pulse-modulated manner. When the infrared radiation passes through the gas chamber, water vapor (water molecules in gaseous state) absorbs some of the energy. The filter extracts the characteristic wavelength portion (e.g., 2.8 μm or 6.5 μm) of the transmitted energy that matches the absorption by water vapor, and the thermopile chip is used to detect the radiation energy. When infrared light passes through the gas chamber, water molecules in gaseous state absorb infrared light in a band that matches their molecular vibration frequency, resulting in a decrease in the intensity of the transmitted light. By detecting the radiation that has been absorbed and irradiated onto the receiving surface of the thermopile chip, the concentration of the gas to be measured can be calculated. The temperature measurement unit 5 uses another surface of the thermopile 6 to receive infrared radiation. The temperature measurement unit 5 has a closed measurement cavity containing a MEMS light source and a second optical receiver 3. Infrared radiation from the light beam introduced into the measurement cavity is received by the thermopile 6, and the ambient temperature can be calculated by measuring the radiant energy. The humidity measurement unit 4 receives an infrared light signal emitted from the infrared light source. This infrared light passes through the measurement cavity (air entering through the air inlet 7). Water vapor absorbs specific wavelengths of infrared light, reducing the intensity of the transmitted light. A filter extracts the characteristic wavelength portion, and one surface of the thermopile 6 receives and detects the radiant energy. The water vapor concentration is calculated using Lambert-Beer's law. The other surface of the thermopile 6 receives infrared radiation, and the ambient temperature is calculated from the radiant energy. The signal output from the thermopile 6 is amplified by an amplifier circuit, converted into a digital signal by an analog-to-digital converter, processed by a central measurement controller, and connected to a computer system for data analysis and display. By fully utilizing the double-sided characteristics of the thermopile chip, the dual functions of humidity and temperature measurement are achieved, improving the sensor's integration and efficiency. It can simultaneously measure air temperature and humidity, providing more comprehensive environmental parameters.

[0030] The sensor of this invention collects a signal composed of two superimposed signals, one representing ambient temperature and the other representing NDIR gas concentration. Specifically, as follows... Figure 5 The diagram illustrates the light source modulation signal and response. The NDIR gas concentration signal is a pulse signal characterized by a positive correlation between the gas concentration and the rate of decrease in the signal peak-to-peak value. That is, the higher the gas concentration, the greater the decrease in the signal peak-to-peak value. The ambient temperature signal is a DC signal, and its intensity is positively correlated with the ambient temperature. The higher the temperature, the stronger the signal.

[0031] In summary, high-precision humidity and temperature measurements are achieved through NDIR technology and the high sensitivity of thermopile 6. The compact design of the multifunctional sensor makes it suitable for integration into various devices and systems. Enhanced filtering and shielding designs reduce the impact of ambient light and other interference on measurement accuracy. Optimized light source and circuit design reduce system power consumption, making it suitable for battery-powered applications. Consideration is also given to expanding the measurement capabilities for other gases or parameters, increasing the sensor's versatility. The technical solution provided in this embodiment innovatively utilizes the double-sided characteristics of the thermopile chip to achieve simultaneous measurement of air temperature and humidity. This solution not only improves the sensor's integration and efficiency but also achieves high-precision measurement through NDIR technology and the high sensitivity of thermopile 6. The compact system design makes it suitable for integration into various devices and systems, offering broad application prospects.

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

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

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

[0035] Specifically, the design of the sensing function unit 1 of this multifunctional sensor system has been further optimized. The sensing function unit 1 includes a first thermopile 61 and a second thermopile 62, both of which interface with the light signal emitted by the infrared light source received by the humidity measurement unit 4, and respectively form a dynamic humidity measurement channel and a reference humidity measurement channel within the measurement cavity of the temperature measurement unit 5. This design aims to improve the stability and accuracy of temperature measurement through comparative measurement. Regarding the humidity measurement module, the first optical receiver 2 in its core NDIR module uses a narrowband filter with a center wavelength of 2.5-6.5µm. This band includes the main absorption characteristic bands of water vapor (such as 2.8µm or 6.5µm), effectively capturing the infrared radiation energy absorbed by water vapor and guiding it to the A-side of the thermopile 61 and thermopile 62 for detection. Meanwhile, the second optical receiver 3 of the humidity measurement module (used in the temperature measurement module) uses a bandpass filter with a center wavelength of 8-14µm. This wavelength band (atmospheric window) typically matches the main peak region of ambient thermal radiation (blackbody radiation) and is relatively unaffected by absorption peaks of gases such as water vapor, making it ideal for measuring ambient temperature. In a more preferred embodiment, to improve the collection efficiency and accuracy of infrared radiation, the second optical receiver 3 (temperature measurement module) can optionally employ an infrared lens to focus radiant 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 element, optimizes the optical path design, and is expected to improve 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 band, and optionally an infrared lens). Combining the previously described core elements such as the NDIR module (MEMS light source, high reflectivity chamber, narrowband filter), 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 high-modulation-performance MEMS light source to meet specific modulation frequency, depth, and duty cycle requirements. A lower duty cycle is preferred to suit the response characteristics of the thermopile 6. The gas chamber uses high-reflectivity materials or surface treatments (such as coatings) to enhance the multiple reflections of infrared light internally, improving interaction with water vapor and energy transfer efficiency. This module is equipped with a narrowband filter to select a wavelength band (e.g., 2.8μm or 6.5μm) that matches the water vapor absorption characteristics, and a reference channel filter (e.g., 3.95μm) to eliminate ambient gas interference and provide a calibration signal. When infrared light passes through the gas chamber, water vapor absorbs some of the energy. One surface (A-side) of the thermopile 6 receives the absorbed radiation and outputs a periodic pulse signal related to the water vapor concentration. The peak-to-peak value decrease is positively correlated with the gas concentration.The other part of the humidity measurement, the temperature measurement module, utilizes another surface (surface B) of the thermopile 6 to receive ambient thermal radiation. By using long-pass or band-pass filters, this module can eliminate interference from common gases in the environment (such as water vapor and carbon dioxide) on temperature measurement, and a reference channel of the same wavelength can be set to improve accuracy. Both surfaces A and B of the thermopile 6 operate based on the Seebeck effect, absorbing infrared radiation to generate a thermoelectric voltage. This voltage signal is positively correlated with the ambient temperature, and the ambient temperature can be calculated through measurement and calibration. Furthermore, for example... Figure 4 As shown, the thermopile array technology mentioned in the solution demonstrates the possibility of further expansion. By integrating multiple detection units with an infrared optical system, it can not only measure the ambient temperature distribution but also obtain the spatial relative humidity distribution by combining NDIR functionality. This is of great value for fields such as environmental monitoring and climate control. Taking a 16*16 thermopile array device as an example, by dividing the measurement space into zones and corresponding each pixel of the thermopile array with an infrared lens, the temperature distribution in the measurement environment can be obtained, such as... Figure 6 As shown: lighter colors indicate higher temperatures, and darker colors indicate lower temperatures. Given the measured absolute humidity, the relative humidity distribution of the measured space can be calculated based on the spatial temperature distribution and absolute humidity. Under the same absolute humidity conditions, relative humidity is negatively correlated with spatial temperature; the higher the temperature, the lower the relative humidity. Figure 7 As shown, the signal acquired by the sensor is a superposition of the NDIR gas concentration signal (pulse) and the ambient temperature signal (DC). Based on the superposition principle, subsequent processing will separate and demodulate these two signals. The sampling frequency is set according to the Nyquist sampling theorem and must be greater than twice the highest frequency of the signal to ensure distortion-free recovery. This scheme, through a MEMS light source, a high-reflectivity gas chamber, a narrow-band filter (corresponding to surface A in thermopile 6), a long-pass / band-pass filter (corresponding to surface B in thermopile 6), and signal processing technology, not only improves the sensor's integration and efficiency but also achieves high-precision and comprehensive monitoring of environmental parameters. Its compact design makes it easy to integrate into various devices and systems, and it has broad application prospects.

[0036] Furthermore, preferably, the air inlet 7 is disposed on the two cavity walls of the measuring cavity, and multiple air inlets 7 are provided, with one air inlet 7 disposed opposite to another air inlet 7.

[0037] Furthermore, the light source installed in the sensing function unit 1 adopts infrared light with high modulation characteristics.

[0038] Specifically, the multifunctional sensor system has been further optimized in its detailed design to improve performance and stability. In the NDIR module of the humidity measurement module, multiple air inlets 7 are symmetrically arranged on the two walls of the measurement chamber, with one air inlet 7 positioned opposite to another. This layout design aims to ensure that the air to be measured can enter the measurement chamber uniformly and quickly, making full contact with the infrared light, thereby improving the accuracy and response speed of water vapor concentration measurement. However, if the air inlets 7 are not positioned opposite each other, it can enhance the flow of gas within the chamber, keeping the humidity within the chamber uniform. Therefore, the air inlets 7 are arranged in an open configuration. Simultaneously, the light source installed in the sensing functional unit 1 uses a high-modulation infrared light source. This ensures that the emitted infrared light meets specific modulation frequency, depth, and duty cycle requirements, which is crucial for subsequent signal processing to distinguish water vapor concentration signals from ambient temperature signals. As mentioned earlier, the NDIR section of the humidity measurement module uses a MEMS light source (as one specific implementation of high modulation characteristics). The infrared light emitted by this source undergoes multiple reflections within a high-reflectivity gas chamber, is selected by a narrow-band filter (first optical receiver 2) with a center wavelength of 2.5-6.5µm, and illuminates surface A of the thermopile 6 for water vapor concentration detection. Regarding the temperature measurement module, the first thermopile 61 and the second thermopile 62 within the sensing function unit 1 are respectively interfaced with the light signal emitted by the infrared light source received by the humidity measurement unit 4, forming a dynamic humidity measurement channel and a reference humidity measurement channel within the measurement cavity to improve the accuracy of temperature measurement. The second optical receiver 3 uses a bandpass filter with a center wavelength of 8-14µm (or, in a preferred embodiment, an infrared lens in conjunction with this filter) to measure ambient humidity. All these signals, including the NDIR gas concentration signal (pulse) and the ambient humidity signal (DC), such as... Figure 8 As shown, the signal superposition and separation methods are employed. The signals are superimposed in the same output channel, and then separated, demodulated, and processed according to the superposition principle and the Nyquist sampling theorem. 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 optimized air inlet 7 layout and light source selection. Its compact design makes it easy to integrate into various devices and systems, and it has broad application prospects.

[0039] Furthermore, the thermopile 6 includes multiple thermocouples, which are connected in series within the thermopile 6.

[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, this multifunctional sensor system features further refinement in its core sensing elements and optical design. The thermopile 6, a key photoelectric conversion element, incorporates multiple thermocouples connected in series to enhance signal output and improve sensor sensitivity and response speed. In the NDIR section of the humidity measurement module, the optical receiver is more precisely 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 used for humidity measurement, with a narrow-band filter having a center wavelength of 2.5-6.5 μm) is set to match the center wavelength (e.g., 2.8 μm or 6.5 μm) of the strong absorption band in the infrared absorption spectrum of water molecules. This allows the sensor to maximize the capture of the infrared absorption signal from water vapor, thereby improving the sensitivity of humidity measurement. Conversely, the center wavelength of the optical receiver corresponding to the second thermopile 62 (i.e., the receiver used for temperature measurement, with a bandpass filter having a center wavelength of 8-14 μm) is set to match the center wavelength of the weak absorption band in the infrared absorption spectrum of water molecules. This design can be used to achieve more accurate temperature compensation or as a reference signal for temperature measurement, especially in the presence of moisture interference. Selecting a weak absorption band can reduce the impact of moisture on temperature measurement and improve its accuracy. Combining the previously described core elements—symmetrical air inlet 7, high-modulation infrared light source, dynamic and reference humidity measurement channels, signal superposition and separation processing, and the thermopile 6 dual-sided sensing—this scheme 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 measurement stability and reliability through optimized optical path design and thermopile 6 structure. Its compact design makes it easy to integrate into various devices and systems, offering broad application prospects.

[0042] Furthermore, the multifunctional sensor superimposes the acquired temperature and water vapor concentration signals to generate a thermopile 6 response signal, which is then sent to the amplification circuit through the same output channel. The thermopile 6 response signal is processed by the central measurement controller, which outputs the results to the computer system. The signal output can take the following forms: Figure 3 The two output schemes shown provide analog and / or digital outputs for the sensor, respectively, depending on the actual application scenario.

[0043] This invention discloses a humidity sensing system for simultaneously measuring air temperature and humidity. The sensing system includes 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. 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 measuring unit 4, a temperature measuring unit 5, and a sensing function unit 1. The humidity measuring unit 4 is hollow, forming a measuring cavity. The sensing function unit 1 is disposed between the humidity measuring unit 4 and the temperature measuring unit 5, connecting the two units. A heat exchanger is installed inside the sensing function unit 1. The thermopile 6 has a first optical receiver 2 inside the humidity measuring unit 4 and a second optical receiver 3 inside the temperature measuring unit 5. An infrared light source inlet is located at the end of the humidity measuring unit 4 furthest from the sensing unit 1, with the light beam introduced by the inlet moving towards the sensing unit 1. Multiple air inlets 7 are located on the sidewall of the humidity measuring unit 4. Similarly, an infrared light source inlet is located at the end of the temperature measuring unit 5 furthest from the sensing unit 1, with the light beam introduced by the inlet moving towards the sensing unit 1. The temperature measuring unit 5 has a hollow interior forming a measuring cavity, which is a closed cavity. Sensing layers are provided on the surfaces of the thermopile 6 facing both the humidity measuring unit 4 and the temperature measuring unit 5. This sensor control system has significant advantages. First, it achieves spatial consistency by using a single sensor device to simultaneously measure air temperature and humidity, avoiding measurement deviations that may occur due to positional differences when using multiple independent sensors. This invention ensures that temperature and humidity measurements are performed at the same spatial point, thus obtaining more accurate and representative environmental parameter data. Second, it guarantees temporal consistency. Since the temperature and humidity signals are acquired by the same sensor at the same time, strict temporal synchronization between the two is guaranteed. This enables the sensor to provide accurate time-matched data, effectively avoiding analytical errors that may be introduced by asynchronous sampling times of different sensors. This invention significantly reduces system complexity. At the hardware level, it reduces the number of required sensors and corresponding wiring, making the overall hardware structure of the sensing system simpler. At the data processing level, since temperature and humidity signals originate from the same source, the data itself has inherent consistency. Therefore, there is no need to consider data synchronization and calibration issues between different sensors during processing, greatly simplifying the data processing flow. In summary, through its unique single-sensor design, it not only improves measurement accuracy and synchronization but also significantly simplifies system configuration and data processing, providing an efficient, reliable, and easily integrated 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 these modifications or substitutions 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 humidity sensing system for simultaneously measuring air temperature and air humidity, the sensing system 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 includes: The unit includes a humidity measurement section, a temperature measurement section, and a sensing function section, wherein the humidity measurement section has a hollow interior forming a measurement cavity. The sensing function unit is disposed between the humidity measuring unit and the temperature measuring unit and connects the humidity measuring unit and the temperature measuring unit. A thermopile is disposed in the sensing function unit, a first optical receiver is disposed in the humidity measuring unit, and a second optical receiver is disposed in the temperature measuring unit. An infrared light source inlet is provided at the end of the humidity measuring unit away from the sensing function unit. The light beam introduced by the infrared light source inlet moves towards the sensing function unit. Multiple air inlets are provided on the side wall of the humidity measuring unit. The infrared light emitted by the infrared light source inlet is reflected multiple times through the air chamber formed by the humidity measuring unit. An infrared light source inlet is provided at the end of the temperature measuring unit away from the sensing function unit. The light beam introduced by the infrared light source inlet moves towards the sensing function unit. The interior of the temperature measuring unit is hollow, forming a measuring cavity. The measuring cavity of the temperature measuring unit is a closed cavity. Sensing layers are provided on the surfaces of the thermopile facing the humidity measuring unit and the temperature measuring unit; The sensing function unit is provided with a first thermopile and a second thermopile. The first thermopile is connected to the light signal emitted by the infrared light source received by the humidity measurement unit and forms a dynamic humidity measurement channel in the measurement cavity of the humidity measurement unit. The second thermopile is connected to the light signal emitted by the infrared light source received by the humidity measurement unit and forms a reference humidity measurement channel in the measurement cavity of the humidity measurement unit. The center wavelength of the first 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 first 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. 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 amplification circuit through the same output channel. The thermopile response signal is processed by the central measurement controller, which outputs the result to the computer system.

2. The humidity sensing system according to claim 1, characterized in that, The second optical receiver uses an infrared lens.

3. The humidity sensing system according to claim 1, characterized in that, The air inlets are located on the two side walls of the measuring chamber, and there are multiple air inlets, with one air inlet positioned opposite to another.

4. The humidity sensing system according to claim 1, characterized in that, The light source installed in the sensing function unit adopts infrared light with high modulation characteristics.

5. The humidity sensing system according to claim 1, characterized in that, The thermopile includes multiple thermocouples, which are connected in series within the thermopile.

Images