Quick response humidity sensor based on active regulation and control technology

Abstract

The invention discloses a quick response humidity sensor based on an active regulation and control technology, which comprises a sensitive and accelerated dehumidification composite structure, a humidification spraying device, a dehumidification spraying device and a control system, and is characterized in that the sensitive and accelerated dehumidification composite structure converts the humidity change in the environment into an electric signal and outputs the electric signal to the control system; the control system starts the humidifying spraying device to spray liquid steam I to cover the surface of the sensitive and accelerated dehumidification composite structure, and the moisture absorption response of the humidity-sensitive material is accelerated; when the environment humidity is reduced, the control system starts the dehumidification spraying device to spray liquid steam II to cover the surface of the sensitive and accelerated dehumidification composite structure, evaporation of water molecules on the surface of the humidity-sensitive material is accelerated through the liquid steam II, meanwhile, the sensitive and accelerated dehumidification composite structure generates high-frequency vibration, the water molecules on the surface are rapidly removed, and the efficient dehumidification function is achieved. The humidity can still be accurately and rapidly detected when the humidity changes rapidly, and the response speed, sensitivity and stability are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of humidity sensors, and in particular to a fast-response humidity sensor based on active regulation technology. Background Art

[0002] Humidity sensors play a vital role in modern industry, agriculture, meteorological monitoring and environmental control. With the advancement of science and technology, the performance requirements of humidity sensors are constantly increasing, especially in terms of response speed, sensitivity and stability. Traditional humidity sensors usually rely on passive humidity sensing materials, which have a long response time and are difficult to meet the needs of real-time monitoring under rapidly changing environmental conditions.

[0003] In 2015, Zuo Qingyun (name) and others introduced grooves or other structures in the hygroscopic material layer to increase its surface area to shorten the movement path of water molecules, thereby improving the response speed. They formed multiple grooves between the metal interdigitated electrode layers to expose the surface area of ​​the hygroscopic material to the environment, significantly improving the response performance of the sensor. In 2022, Xu Shiyao (name) and others doped nano-SiO2 microspheres in the hygroscopic material, which can significantly improve the response recovery characteristics of the humidity sensor. Studies have shown that the humidity response time of this organic-inorganic hybrid material is less than 1.5 seconds and the recovery time is less than 18 seconds. The introduction of nanomaterials increases the specific surface area of ​​the material, thereby accelerating the adsorption and desorption process of water molecules. In 2017, a new solid-state humidity sensor developed by NASA used ceramic dielectric materials, which showed extremely high sensitivity to changes in water vapor concentration and faster response and recovery speed. The sensor is suitable for application scenarios requiring high sensitivity and fast response. All of the above studies use the optimization of sensor materials and sensitive structures to speed up the sensor response speed, and it is difficult to make necessary adjustments according to actual application scenarios. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a fast-response humidity sensor based on active control technology, which realizes intelligent self-feedback control by integrating a humidification spray device and a dehumidification spray device and combining an ultrasonic accelerated dehumidification structure, thereby significantly improving the response speed of the humidity sensor.

[0005] Technical solution: The fast response humidity sensor based on active control technology described in the present invention includes: a sensitive and accelerated dehumidification composite structure, a humidifying spray device, a dehumidification spray device and a control system. The sensitive and accelerated dehumidification composite structure is used to detect humidity changes in the environment, and convert the humidity changes into electrical signals and output them to the control system. When the ambient humidity increases, the control system starts the humidifying spray device to spray liquid vapor I to cover the surface of the sensitive and accelerated dehumidification composite structure, thereby accelerating the moisture absorption response of the moisture-sensitive material; when the ambient humidity decreases, the control system starts the dehumidification spray device to spray liquid vapor II to cover the surface of the sensitive and accelerated dehumidification composite structure, and the liquid vapor II is used to accelerate the evaporation of water molecules on the surface of the moisture-sensitive material. At the same time, the ultrasonic accelerated dehumidification structure inside the sensitive and accelerated dehumidification composite structure generates high-frequency vibrations to quickly remove water molecules on the surface, thereby achieving an efficient dehumidification function.

[0006] Optionally, the sensitive and accelerated dehumidification composite structure includes: a silicon substrate, an ultrasonic accelerated dehumidification structure covering the upper surface of the silicon substrate, and a humidity-sensitive material covering the surface of the ultrasonic accelerated dehumidification structure; the humidity-sensitive material is used to detect changes in ambient humidity, and the ultrasonic accelerated dehumidification structure converts changes in ambient humidity into electrical signals and transmits them to the control system.

[0007] Optionally, the ultrasonic accelerated dehumidification structure includes a lower electrode, a piezoelectric medium covering the upper surface of the lower electrode, and a finger electrode pair arranged on the upper surface of the piezoelectric medium; the lower electrode, the piezoelectric medium and the finger electrode pair form an ultrasonic drive port, and when ultrasonic drive is performed, the two electrodes in the finger electrode pair are of equal potential and serve as one pole of the drive port, and the lower electrode serves as the other pole of the drive port; the finger electrode pair and the humidity-sensitive material form a humidity-sensitive structure, and when humidity detection is performed, the two electrodes in the finger electrode pair are independent of each other and serve as the two-pole output of the detection port, converting the environmental humidity changes into electrical signals and transmitting them to the control system.

[0008] Optionally, the humidifying spray device and the dehumidifying spray device have the same structure, including a cavity, a piezoelectric dual chip located in the cavity, a capillary channel connected to the cavity, a heating device for heating the liquid in the capillary channel, a spray port connected to the capillary channel outlet, and a liquid inlet connected to the other end of the cavity; the liquid vapor sprayed from the spray port covers the surface of the sensitive and accelerated dehumidification composite structure.

[0009] Optionally, the piezoelectric bimorph is driven by a vibration frequency and amplitude control system, and the vibration frequency and amplitude of the piezoelectric bimorph are adjusted as needed to adjust the release speed of the liquid vapor.

[0010] Optionally, the vibration frequency and amplitude of the piezoelectric dual crystal also need to be coordinated with the tension of the capillary channel.

[0011] Optionally, the heating device includes a temperature control device for adjusting the temperature of the liquid as required to control the evaporation rate of the liquid.

[0012] Optionally, the heating device is a heating resistor, which is arranged on the outer wall of the capillary channel.

[0013] Optionally, the liquid in the humidifying spray device is water, and the liquid in the dehumidifying spray device is a volatile liquid soluble in water.

[0014] Working principle:

[0015] Humidity detection: The humidity-sensitive material detects changes in humidity in the environment, and its own resistance / capacitance changes accordingly, and an electrical signal representing the humidity is output through the first interdigitated electrode and the second interdigitated electrode.

[0016] Humidity response: Since the response of the humidity sensor is based on the diffusion movement of water molecules, the diffusion rate is proportional to the concentration gradient of water molecules. When the external humidity changes are detected, the humidity difference between the sensitive material (i.e., the humidity-sensitive material) and the external environment is actively increased according to the detected sensor characterization output parameters, which is conducive to the rapid diffusion of water molecules and the establishment of balance.

[0017] Humidity rise: When humidity rise is detected, the resistance / capacitance of the humidity-sensitive material changes accordingly, and the first interdigitated electrode and the second interdigitated electrode transmit the change in resistance / capacitance of the humidity-sensitive material to the control system, which starts the humidification spray device composed of the first cavity to the first spray port. The first heating resistor heats the water in the first cavity, and the first piezoelectric bimorph generates high-frequency vibrations, vaporizes the water and transports it to the first spray port through the first capillary channel, spraying water vapor to the surface of the humidity-sensitive material of the humidity sensor, accelerating the diffusion of water molecules and increasing the moisture absorption rate of the humidity sensor. The amount of water vapor sprayed is adjusted according to the rate of change of the resistance / capacitance output by the first interdigitated electrode and the second interdigitated electrode over time.

[0018] Humidity drop: When humidity drop is detected, the resistance / capacitance of the humidity-sensitive material changes accordingly, and the first interdigitated electrode and the second interdigitated electrode transmit the change in resistance / capacitance of the humidity-sensitive material to the control system, and the control system starts the dehumidification spray device composed of the second cavity to the second spray port. The second heating resistor heats the water-soluble volatile liquid in the second cavity, and the second piezoelectric bimorph generates high-frequency vibration, vaporizes the water-soluble volatile liquid and transports it to the second spray port through the second capillary channel, and transports the water-soluble volatile liquid vapor to the surface of the humidity-sensitive material of the sensor, and accelerates the evaporation of water molecules in the humidity-sensitive material through the water-soluble volatile liquid vapor, and quickly removes water molecules through the high-frequency vibration generated by the ultrasonic accelerated dehumidification structure composed of the lower electrode, piezoelectric medium, first interdigitated electrode and second interdigitated electrode, thereby increasing the dehumidification speed of the humidity sensor. The amount of water-soluble volatile liquid vapor sprayed and the power output of the ultrasonic accelerated dehumidification structure are adjusted according to the rate of change of the resistance / capacitance output by the first interdigitated electrode and the second interdigitated electrode over time.

[0019] Beneficial effects: Compared with the prior art, the significant technical effects of the present invention are: by integrating the humidification and dehumidification spray device, the rapid moisture absorption and dehumidification function of the humidity sensor is realized, which greatly improves the response speed and accuracy of the humidity sensor. At the same time, the humidity response is adjusted instantly by the control system, which effectively adapts to environmental changes and ensures the accuracy and timeliness of humidity monitoring. The sensor has a wide range of application prospects, and is particularly suitable for industrial production, environmental monitoring, weather stations, smart homes and other fields that require rapid humidity monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of the humidity sensor of the present invention;

[0021] Figure 2 Schematic diagram of the interdigitated electrode pair structure. DETAILED DESCRIPTION

[0022] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] The fast response humidity sensor based on active control technology described in the present invention includes: a sensitive and accelerated dehumidification composite structure, a humidifying spray device, a dehumidifying spray device and a control system. The sensitive and accelerated dehumidification composite structure is used to detect humidity changes in the environment and convert the humidity changes into electrical signals and output them to the control system. When the ambient humidity increases, the control system starts the humidifying spray device to spray liquid vapor I to cover the surface of the sensitive and accelerated dehumidification composite structure, thereby accelerating the moisture absorption response of the moisture-sensitive material; when the ambient humidity decreases, the control system starts the dehumidifying spray device to spray liquid vapor II to cover the surface of the sensitive and accelerated dehumidification composite structure, and the evaporation of water molecules on the surface of the moisture-sensitive material is accelerated by the liquid vapor II. At the same time, the ultrasonic accelerated dehumidification structure inside the sensitive and accelerated dehumidification composite structure generates high-frequency vibrations to quickly remove water molecules on the surface, thereby achieving an efficient dehumidification function.

[0024] like Figure 1 As shown, the sensitive and accelerated dehumidification composite structure includes: a silicon substrate 1, an ultrasonic accelerated dehumidification structure covering the upper surface of the silicon substrate 1, and a hygroscopic material 5 covering the surface of the ultrasonic accelerated dehumidification structure; the ultrasonic accelerated dehumidification structure includes a lower electrode 2, a piezoelectric medium 3 covering the upper surface of the lower electrode 2, and a pair of interdigitated electrodes arranged on the upper surface of the piezoelectric medium; the lower electrode 2, the piezoelectric medium 3 and the pair of interdigitated electrodes form an ultrasonic drive port; the hygroscopic material 5 is used to detect changes in ambient humidity, and the pair of interdigitated electrodes serves as a detection output port to convert changes in ambient humidity into electrical signals and transmit them to the control system. Specifically:

[0025] The silicon substrate 1 serves as the base of the sensor and the basic layer, and is used to provide mechanical support and stability for the entire sensor; other layers of components are covered on the silicon substrate.

[0026] Lower electrode 2: Covering on the silicon substrate 1, forming a circuit connection with the subsequent piezoelectric medium 3 and the interdigitated electrode pair, and playing the role of an ultrasonic driving port.

[0027] Piezoelectric medium 3: covers the lower electrode 2, has piezoelectric effect, and is used to excite high-frequency vibration.

[0028] The interdigital electrode pair includes a first interdigital electrode 4A and a second interdigital electrode 4B, which are located above the piezoelectric medium. The first interdigital electrode 4A and the second interdigital electrode 4B are arranged alternately to form an interdigital structure, such as Figure 2 The interdigitated electrode pair and the humidity sensitive material 5 covering the surface thereof form a humidity sensitive structure for detecting humidity changes.

[0029] The humidity sensitive material 5 covers the surface of the piezoelectric medium 3 and the first interdigitating electrode 4A and the second interdigitating electrode 4B, and senses the humidity change in the environment when in contact with the environment, resulting in the change of its own resistance or capacitance.

[0030] The humidifying spray device and the dehumidifying spray device have the same structure, including a cavity, a piezoelectric dual chip located in the cavity, a capillary channel connected to the cavity, a heating device for heating the liquid in the capillary channel, a spray port connected to the capillary channel outlet, and a liquid inlet connected to the other end of the cavity; the liquid vapor sprayed from the spray port covers the surface of the sensitive and accelerated dehumidification composite structure.

[0031] In this embodiment, the heating device is a heating resistor, which is arranged on the outer wall of the capillary channel. The liquid added to the humidification spray device is water. The liquid added to the dehumidification spray device is a volatile liquid soluble in water, such as ethanol.

[0032] Specific as Figure 1 As shown:

[0033] The humidifying spray device includes a first cavity 6A, a first piezoelectric dual chip 7A, a first capillary channel 8A, a first heating resistor 9A, a first spray port 10A and a first liquid inlet 11A, and the dehumidifying spray device includes a second cavity 6B, a second piezoelectric dual chip 7B, a second capillary channel 8B, a second heating resistor 9B, a second spray port 10B and a second liquid inlet 11B.

[0034] The first cavity 6A and the second cavity 6B are used to contain water and ethanol liquids respectively, providing liquids required for spraying. The cavities are sealed to prevent liquid leakage and ensure safe storage.

[0035] The first piezoelectric bimorph 7A and the second piezoelectric bimorph 7B are respectively located inside the first cavity 6A and the second cavity 6B, and vaporize the liquid in the corresponding cavity through high-frequency vibration. The high-frequency vibration of the first piezoelectric bimorph 7A and the second piezoelectric bimorph 7B is driven by the control system.

[0036] The first capillary channel 8A and the second capillary channel 8B are used to temporarily store the liquid and allow the liquid to flow slowly to the spray port. The first capillary channel 8A and the second capillary channel 8B transmit the liquid through tension to prevent leakage.

[0037] The first heating resistor 9A and the second heating resistor 9B heat the water and ethanol liquid transmitted through the capillary channel respectively, so that the liquid quickly vaporizes and turns into water vapor and ethanol vapor.

[0038] The first spray port 10A and the second spray port 10B are used to transport vaporized water vapor and ethanol vapor to the surface of the moisture-sensitive material 5 of the sensitive and accelerated dehumidification composite structure surface.

[0039] The first liquid inlet 11A and the second liquid inlet 11B are used to replenish the water and ethanol liquid in the cavity to ensure the continuity and stability of the liquid supply.

[0040] The first piezoelectric dual chip 7A and the second piezoelectric dual chip 7B are driven by a vibration frequency and amplitude control system. The vibration frequency and amplitude of the first piezoelectric dual chip 7A and the second piezoelectric dual chip 7B can be adjusted as needed to adjust the release rate of water vapor or ethanol vapor. At the same time, the vibration frequency and amplitude of the first piezoelectric dual chip 7A and the second piezoelectric dual chip 7B need to cooperate with the tension of the first capillary 8A and the second capillary 8B to avoid liquid leakage.

[0041] The first heating resistor 9A and the second heating resistor 9B both include a temperature control device, which can adjust the temperature of the liquid in the capillary channel as needed to control the evaporation rate of the liquid and ensure that the liquid vapor can be ejected quickly.

[0042] The working process and self-feedback control process of the humidity sensor related to this embodiment are as follows:

[0043] Humidity rise response: When the ambient humidity increases, the resistance / capacitance of the moisture-sensitive material 5 changes accordingly, and the first interdigitated electrode 4A and the second interdigitated electrode 4B output the signal to the control system. The control system starts the humidification spray device (the path from the first cavity 6A to the first spray port 10A), the first heating resistor 9A heats the water in the first cavity 6A, and the first piezoelectric bimorph 7A generates high-frequency vibration, vaporizes the water and transports it to the first spray port 10A through the first capillary 8A. The sprayed water vapor quickly covers the surface of the moisture-sensitive material, accelerates the moisture absorption response of the moisture-sensitive material, and enhances its detection accuracy.

[0044] Humidity drop response: When the ambient humidity decreases, the resistance / capacitance value of the moisture-sensitive material 5 changes accordingly, and the first interdigitated electrode 4A and the second interdigitated electrode 4B transmit the change to the control system. The control system starts the dehumidification spray device (the path from the second cavity 6B to the second spray port 10B), the second heating resistor 9B heats the ethanol in the second cavity 6B, and the second piezoelectric bimorph 7B drives the ethanol to vaporize. The transported ethanol vapor covers the surface of the moisture-sensitive material, and the ethanol vapor accelerates the evaporation of water molecules in the moisture-sensitive material. At the same time, the ultrasonic acceleration dehumidification structure generates high-frequency vibrations, quickly removes water molecules on the surface of the moisture-sensitive material, and realizes an efficient dehumidification function.

[0045] In this embodiment, the sensor adopts an intelligent feedback control mechanism:

[0046] By detecting the rate of change of resistance / capacitance over time, the sensor can automatically adjust the amount of water vapor or ethanol vapor sprayed. The specific implementation steps are as follows:

[0047] Vibration control: By adjusting the vibration frequency and amplitude of the first piezoelectric bimorph 7A and the second piezoelectric bimorph 7B, the spray device can accurately control the release rate of water or ethanol to avoid excessive or insufficient liquid.

[0048] Temperature control: The first heating resistor 9A and the second heating resistor 9B are built with a temperature controller for adjusting the temperature of water or ethanol to meet the needs of different humidity environments and ensure the optimal balance between response speed and detection accuracy.

[0049] The fast-response humidity sensor based on active control technology described in the present invention solves the problem that traditional humidity sensors have slow response speeds and are difficult to adapt to rapidly changing environments. The sensor integrates a humidification and dehumidification spray device and combines it with a piezoelectric ultrasonic structure to achieve intelligent self-feedback control of humidity detection. The core innovation of the sensor lies in actively regulating the humidity difference between the humidity-sensitive material and the environment so that the humidity-sensitive structure responds quickly when the humidity changes, thereby improving the response speed and detection accuracy. Specifically, the sensitive and accelerated dehumidification composite structure of the humidity sensor is used to sense humidity changes and output resistance or capacitance signals, and the humidification and dehumidification spray device vaporizes water and ethanol liquids through high-frequency vibrations, and then transports them to the sensor surface through capillaries. Its working principle is: when the external humidity increases, the resistance or capacitance value of the humidity-sensitive material changes, the control system starts the humidification spray device, and transports water vapor to the surface of the humidity-sensitive material through heating and piezoelectric vibration, and quickly increases the moisture absorption rate of the humidity sensor; when the external humidity decreases, the control system starts the dehumidification spray device, and also vaporizes ethanol and transports it to the surface of the humidity-sensitive material through heating and vibration. The ethanol vapor accelerates the evaporation of water molecules, and then quickly removes water molecules through high-frequency vibration to achieve efficient dehumidification response. The sensor has an intelligent control mechanism, which can automatically adjust the amount of water vapor or ethanol ejected according to the rate of change of the resistance / capacitance of the humidity-sensitive material over time, and adapt to different environmental humidity requirements by controlling the vibration frequency and heating temperature, ensuring the optimal balance between the sensor response speed and detection accuracy. The present invention actively controls the humidity difference on the surface of the humidity-sensitive material, so that the sensor can still accurately and quickly detect humidity when the humidity changes rapidly, effectively improving the response speed, sensitivity and stability, and is particularly suitable for application scenarios such as industrial production, environmental monitoring, weather stations, and smart homes that require real-time humidity monitoring.

[0050] The above is only a preferred embodiment of 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 principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A fast response humidity sensor based on active control technology, characterized in that: include: A sensitive and accelerated dehumidification composite structure, a humidifying spray device, a dehumidifying spray device and a control system. The sensitive and accelerated dehumidification composite structure is used to detect humidity changes in the environment and convert the humidity changes into electrical signals and output them to the control system. When the ambient humidity increases, the control system starts the humidifying spray device to spray liquid vapor I to cover the surface of the sensitive and accelerated dehumidification composite structure, thereby accelerating the moisture absorption response of the moisture-sensitive material. When the ambient humidity decreases, the control system starts the dehumidifying spray device to spray liquid vapor II to cover the surface of the sensitive and accelerated dehumidification composite structure, and the liquid vapor II is used to accelerate the evaporation of water molecules on the surface of the moisture-sensitive material. At the same time, the ultrasonic accelerated dehumidification structure inside the sensitive and accelerated dehumidification composite structure generates high-frequency vibrations to quickly remove water molecules on the surface, thereby achieving an efficient dehumidification function.

2. The fast response humidity sensor based on active control technology according to claim 1 is characterized in that: The sensitive and accelerated dehumidification composite structure comprises: a silicon substrate (1), an ultrasonic accelerated dehumidification structure covering the upper surface of the silicon substrate (1), and a moisture-sensitive material (5) covering the surface of the ultrasonic accelerated dehumidification structure; the moisture-sensitive material (5) is used to detect changes in environmental humidity, and the ultrasonic accelerated dehumidification structure converts the changes in environmental humidity into electrical signals and transmits them to a control system.

3. The fast response humidity sensor based on active control technology according to claim 2 is characterized in that: The ultrasonic accelerated dehumidification structure comprises a lower electrode (2), a piezoelectric medium (3) covering the upper surface of the lower electrode (2), and a pair of interdigitated electrodes arranged on the upper surface of the piezoelectric medium; the lower electrode (2), the piezoelectric medium (3) and the pair of interdigitated electrodes form an ultrasonic drive port; when ultrasonic drive is performed, the two electrodes in the pair of interdigitated electrodes have the same potential and serve as one pole of the drive port, and the lower electrode (2) serves as the other pole of the drive port; the pair of interdigitated electrodes and a humidity-sensitive material (5) form a humidity-sensitive structure; when humidity detection is performed, the two electrodes in the pair of interdigitated electrodes are independent of each other and serve as the two-pole output of the detection port, converting the change in environmental humidity into an electrical signal and transmitting it to a control system.

4. The fast response humidity sensor based on active control technology according to claim 1, characterized in that: The humidifying spray device and the dehumidifying spray device have the same structure, including a cavity, a piezoelectric dual chip located in the cavity, a capillary channel connected to the cavity, a heating device for heating the liquid in the capillary channel, a spray port connected to the capillary channel outlet, and a liquid inlet connected to the other end of the cavity; the liquid vapor sprayed from the spray port covers the surface of the sensitive and accelerated dehumidification composite structure.

5. The fast response humidity sensor based on active control technology according to claim 4 is characterized in that: The piezoelectric bimorph is driven by a vibration frequency and amplitude control system. The vibration frequency and amplitude of the piezoelectric bimorph are adjusted as needed, thereby adjusting the release rate of liquid vapor.

6. The fast response humidity sensor based on active control technology according to claim 5, characterized in that: The vibration frequency and amplitude of the piezoelectric dual crystal also need to be coordinated with the tension of the capillary channel.

7. The fast response humidity sensor based on active control technology according to claim 4, characterized in that: The heating device comprises a temperature control device, which adjusts the temperature of the liquid as required to control the evaporation rate of the liquid.

8. The fast response humidity sensor based on active control technology according to claim 4, characterized in that: The heating device is a heating resistor which is arranged on the outer wall of the capillary channel.

9. The fast response humidity sensor based on active control technology according to claim 1, characterized in that: The liquid in the humidifying spray device is water, and the liquid in the dehumidifying spray device is a volatile liquid soluble in water.

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