CN220084771U - Flexible film humidity sensor - Google Patents
Flexible film humidity sensor Download PDFInfo
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- CN220084771U CN220084771U CN202321226739.5U CN202321226739U CN220084771U CN 220084771 U CN220084771 U CN 220084771U CN 202321226739 U CN202321226739 U CN 202321226739U CN 220084771 U CN220084771 U CN 220084771U
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- humidity
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- interdigital electrode
- humidity sensor
- sensitive
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- CWQXQMHSOZUFJS-UHFFFAOYSA-N molybdenum disulfide Chemical compound S=[Mo]=S CWQXQMHSOZUFJS-UHFFFAOYSA-N 0.000 claims abstract description 19
- 229910052982 molybdenum disulfide Inorganic materials 0.000 claims abstract description 19
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 16
- 239000010439 graphite Substances 0.000 claims abstract description 16
- -1 graphite alkyne Chemical class 0.000 claims abstract description 15
- 239000002131 composite material Substances 0.000 claims abstract description 14
- 239000000463 material Substances 0.000 claims description 18
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 7
- 229910052802 copper Inorganic materials 0.000 claims description 7
- 239000010949 copper Substances 0.000 claims description 7
- 229910052709 silver Inorganic materials 0.000 claims description 7
- 239000004332 silver Substances 0.000 claims description 7
- 239000004642 Polyimide Substances 0.000 claims description 6
- 229920001721 polyimide Polymers 0.000 claims description 6
- 229920000139 polyethylene terephthalate Polymers 0.000 claims description 3
- 239000005020 polyethylene terephthalate Substances 0.000 claims description 3
- 239000010408 film Substances 0.000 claims 23
- 239000010409 thin film Substances 0.000 claims 1
- 238000005259 measurement Methods 0.000 abstract description 7
- 230000008859 change Effects 0.000 description 13
- 238000001514 detection method Methods 0.000 description 7
- 230000035945 sensitivity Effects 0.000 description 6
- 239000012528 membrane Substances 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 238000005452 bending Methods 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 229910021389 graphene Inorganic materials 0.000 description 4
- 239000002135 nanosheet Substances 0.000 description 4
- 230000004044 response Effects 0.000 description 4
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 3
- 229910052750 molybdenum Inorganic materials 0.000 description 3
- 239000011733 molybdenum Substances 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 239000000370 acceptor Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- WPYVAWXEWQSOGY-UHFFFAOYSA-N indium antimonide Chemical compound [Sb]#[In] WPYVAWXEWQSOGY-UHFFFAOYSA-N 0.000 description 2
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000026041 response to humidity Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 238000009313 farming Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 230000008447 perception Effects 0.000 description 1
- 239000002210 silicon-based material Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Abstract
The utility model discloses a flexible film humidity sensor which sequentially comprises a graphite alkyne and molybdenum disulfide composite humidity-sensitive film, an interdigital electrode, an insulating film, a spiral coil and a flexible film from top to bottom. Wherein, the surface of the insulating film is provided with a through hole, and the spiral coil is connected with the interdigital electrode through the through hole to form an LC resonance circuit; the graphite alkyne and molybdenum disulfide composite humidity-sensitive film is tightly attached to the interdigital electrode to form a humidity-sensitive unit. When the relative humidity in the environment changes, the dielectric constant of the graphite alkyne and molybdenum disulfide composite humidity-sensitive film on the surface of the interdigital electrode changes, so that the capacitance value of the interdigital electrode changes, and the resonant frequency of the LC humidity sensor shifts. The resonance frequency is wirelessly read through an external reading coil, so that the measurement of external humidity is realized. The utility model has the characteristics of simple circuit, no need of power supply, long service life, miniaturization, convenience, good signal reproducibility and the like, and provides a wide application prospect for the humidity measurement of electronic equipment used in a closed environment.
Description
Technical field:
the utility model relates to the technical field of humidity sensing, in particular to a flexible film humidity sensor.
Technical background:
humidity is a physical quantity used to characterize the moisture content of air. With the progress of society, detection and control of humidity is increasingly important. Humidity sensors are devices that convert the amount of water vapor into a measurable quantity, and have been widely used in the fields of pharmaceutical storage, animal farming, greenhouses, industrial production, and the like. Currently, the main humidity sensor forms are three types of lithium chloride humidity sensor, aluminum oxide sensor and ceramic humidity sensor. In order to improve the practicability of the electronic equipment in the closed space, the matched sensor needs to have the characteristics of low cost, small volume and low power consumption, which is difficult to realize by the traditional electronic device. At present, the development of the electronic sensor capable of sealing the space has a plurality of problems to be solved urgently, including weak endurance, poor measurement precision and stability, large volume and the like.
Most of the existing flexible wireless passive humidity sensors rely on the change of capacitance in the LC resonant circuit, and the increase of capacitance causes the loss of the sensor signal quality factor Q. In order to better meet the actual requirements of equipment used in a closed space, the flexible film humidity sensor provided by the utility model responds to the change of an external field by utilizing a series circuit of an inductor and a capacitor and transmits information in an electromagnetic field. Compared with the existing humidity sensor, the utility model utilizes the change of relative humidity in the environment, and the dielectric constant of the humidity-sensitive film made of the graphite alkyne and molybdenum disulfide composite material on the surface of the interdigital electrode is changed accordingly, so that the capacitance value of the interdigital electrode is changed, and the resonance frequency of the LC-type humidity sensor is shifted. The resonance frequency is wirelessly read through an external reading coil, so that the measurement of external humidity is realized. The utility model has the characteristics of simple circuit, no need of power supply, long service life, miniaturization, convenience, good signal reproducibility and the like, and provides a wide application prospect for the humidity measurement of electronic equipment used in a closed environment.
The utility model comprises the following steps:
the utility model provides a flexible film humidity sensor, which sequentially comprises a graphite alkyne and molybdenum disulfide composite humidity-sensitive film, an interdigital electrode, an insulating film, a spiral coil and a flexible film from top to bottom; the spiral coil and the interdigital electrode are respectively arranged at two sides of the insulating film and are connected through a through hole arranged on the insulating film; the humidity-sensitive film is covered on the interdigital electrode; the flexible film is arranged at the bottom of the sensor.
The square insulating film has better flexibility, separates the spiral coil from the interdigital electrode, and is preferably made of polyimide. Polyimide is a humidity sensitive polymer, and is widely applied to humidity detection materials because of high temperature resistance, low cost, low dielectric constant, good insulating property, high wiring density, light weight, thin thickness, good bending property, simple imidization process, good linearity and high sensitivity when humidity is measured.
In order to improve the accuracy of the humidity sensor, the spiral coil with square shape and the interdigital electrode with square shape are preferably made of copper or silver. Because copper and silver are metal materials with lower resistivity, the LC resonance circuit composed of copper or silver has small impedance, obvious resonance frequency change and higher humidity measurement precision.
Preferably, the square graphite alkyne and molybdenum disulfide composite humidity-sensitive film is covered on the interdigital electrode to form a humidity-sensitive unit. The molybdenum disulfide nanosheets are two-dimensional materials with high specific surface area and adjustable forbidden band gap, and have good application prospects in gas sensitive applications. The molybdenum disulfide nanosheets with different particle sizes and thicknesses can be prepared through ultrasonic stripping, so that the gas sensitivity is improved. The gas molecules will physically adsorb to the disulfideThe molybdenum surface and acts as its charge acceptor or donor role, resulting in a charge transfer phenomenon between the gas molecules and molybdenum disulfide. The carbon atom alkyne bonds in the graphite alkyne structure greatly weaken the hardness of the material compared with graphene, and the in-plane rigidity of the material is reduced along with the increase of the number of the carbon atom alkyne bonds, so that the material is suitable for being used as a flexible material. Graphene has a carrier mobility of about 15000cm at room temperature 2 This value is more than 10 times that of the silicon material, and is more than twice that of indium antimonide (InSb), which is the substance known to have the highest carrier mobility. The molybdenum disulfide-graphite alkyne composite material is a moisture-sensitive film material and has higher surface volume ratio and excellent carrier mobility. The humidity-sensitive film made of the graphite alkyne and molybdenum disulfide composite material is positioned on the top layer of the sensor. The response time is thus shorter, so that the sensitivity of the humidity sensor can be improved.
Preferably, the flexible film with a square shape is made of polyethylene terephthalate, has the characteristic of flexibility and bending, and can provide enough mechanical support for the whole sensor, so that the sensor can adapt to the requirements of various different application scenes.
From the sensor resonant frequency expression:
the sensor resonant frequency is determined only by the variable capacitance C. The variable capacitance is used as an interdigital capacitance. For an interdigital electrode consisting of N pairs of interdigital electrodes, the theoretical calculation expression of the capacitance value is as follows:
wherein l, omega and h are the length, width and thickness of the interdigital, respectively, and epsilon is the dielectric constant of the humidity sensitive layer. As can be seen from a combination of the above two equations, the resonant frequency is determined only by the dielectric constant. When the moisture-sensitive layer continuously absorbs moisture, the dielectric constant will change, so that the resonant frequency will change, and thus the resonant frequency of the LC-type humidity sensor will be shifted. The resonant frequency can be read wirelessly by an external reading coil, so that the relative humidity is calculated.
The side length of the flexible film and the side length of the humidity-sensitive film are 40-50 mm, the side length of the insulating film, the side length of the spiral coil and the side length of the interdigital electrode are 30-40 mm, and the center point of the side length of the flexible film and the side length of the humidity-sensitive film are positioned on the vertexes of the insulating film, the spiral coil and the interdigital electrode. This allows the contact area of the flexible membrane with the interdigitated electrodes to be increased and the sensor to be more sensitive to ambient humidity sensing. Meanwhile, the spiral coil is wrapped by the bottom flexible film, so that the oxidization speed of the spiral coil is reduced.
The humidity sensor provided by the utility model has a flexible multilayer structure, and the top layer humidity-sensitive film is used as a humidity-sensitive layer and is fully contacted with the external environment directly, so that the quick response to humidity change is realized. The spiral coil, the insulating film and the interdigital electrode of the middle layer are used as a conversion component for converting humidity parameters into electrical parameters, so that the structure is compact, and the response of the humidity-sensitive material to humidity can be quickly, sensitively and accurately converted into the change of LC resonance parameters. The flexible membrane at the bottom of the sensor provides sufficient mechanical support for the entire sensor.
The humidity sensor is based on the circuit resonance and magnetic field coupling principle, has the advantages of small volume, long service life, softness, flexibility, simple structure, strong adaptability and good signal reproducibility, and can realize wireless detection of the ambient humidity in the closed space without any active element. Based on the advantages, the humidity sensor can overcome the defects of complexity and diversity of the traditional sensor application scene, is applied to nondestructive detection of humidity in environments such as rotation and sealing, and has wide development prospect in wireless sensor network construction.
Description of the drawings:
the utility model will be further described with reference to the accompanying drawings and examples
Fig. 1 is a schematic structural view of a flexible film humidity sensor.
The specific embodiment is as follows:
the utility model provides a flexible film humidity sensor, which sequentially comprises a graphite alkyne and molybdenum disulfide composite humidity-sensitive film 1, an interdigital electrode 2, an insulating film 3, a spiral coil 4 and a flexible film 5 from top to bottom; the spiral coil 4 and the interdigital electrode 2 are respectively arranged at two sides of the insulating film 3 and are connected through a through hole arranged on the insulating film 3; the humidity-sensitive film 1 is covered on the interdigital electrode 2; the flexible membrane 5 is arranged at the bottom of the sensor.
The square insulating film 3 has better flexibility and separates the spiral coil 4 and the interdigital electrode 2, and the insulating film 3 is preferably made of polyimide. Polyimide is a humidity sensitive polymer, and is widely applied to humidity detection materials because of high temperature resistance, low cost, low dielectric constant, good insulating property, high wiring density, light weight, thin thickness, good bending property, simple imidization process, good linearity and high sensitivity when humidity is measured.
In order to improve the accuracy of the humidity sensor, the spiral coil 4 having a square shape and the interdigital electrode 2 having a square shape are preferably made of copper or silver. Because copper and silver are metal materials with lower resistivity, the LC resonance circuit composed of copper or silver has small impedance, obvious resonance frequency change and higher humidity measurement precision.
Preferably, the square graphite alkyne and molybdenum disulfide composite humidity-sensitive film 1 is covered on the interdigital electrode 2 to form a humidity-sensitive unit. The molybdenum disulfide nanosheets are two-dimensional materials with high specific surface area and adjustable forbidden band gap, and have good application prospects in gas sensitive applications. The molybdenum disulfide nanosheets with different particle sizes and thicknesses can be prepared through ultrasonic stripping, so that the gas sensitivity is improved. The gas molecules will physically adsorb to the surface of molybdenum disulfide and act as their charge acceptors or donors, resulting in charge transfer phenomena between the gas molecules and molybdenum disulfide. The carbon atom alkyne bonds in the graphite alkyne structure greatly weaken the hardness of the material compared with graphene, and the in-plane rigidity of the material is reduced along with the increase of the number of the carbon atom alkyne bonds, so that the material is suitable for being used as a flexible material. Graphene has a carrier mobility of about 15000cm at room temperature 2 /(V.s), this value exceedsSilicon material is 10 times or more than twice that of indium antimonide (InSb), which is the substance with the highest known carrier mobility. The molybdenum disulfide-graphite alkyne composite material is a moisture-sensitive film 1 material and has higher surface volume ratio and excellent carrier mobility. The humidity-sensitive film 1 made of the graphite alkyne and molybdenum disulfide composite material is positioned on the top layer of the sensor. The response time is thus shorter, so that the sensitivity of the humidity sensor can be improved.
Preferably, the square flexible film 5 is made of polyethylene terephthalate, and has the characteristic of flexibility and bending, so that the sensor can adapt to the requirements of various different application scenes.
From the sensor resonant frequency expression:
the sensor resonant frequency is determined only by the variable capacitance C. The variable capacitance is used as an interdigital capacitance. For an interdigital electrode 2 composed of N pairs of interdigital electrodes, the theoretical calculation expression of the capacitance value is:
wherein l, omega and h are the length, width and thickness of the interdigital, respectively, and epsilon is the dielectric constant of the humidity sensitive layer. As can be seen from a combination of the above two equations, the resonant frequency is determined only by the dielectric constant. When the moisture-sensitive layer continuously absorbs moisture, the dielectric constant will change, so that the resonant frequency will change, and thus the resonant frequency of the LC-type humidity sensor will be shifted. The resonant frequency can be read wirelessly by an external reading coil, so that the relative humidity is calculated.
The side length of the flexible film 5 and the side length of the humidity-sensitive film 1 are 40-50 mm, the side length of the insulating film 3, the spiral coil 4 and the side length of the interdigital electrode 2 are 30-40 mm, and the center point of the side length of the flexible film 5 and the side length of the humidity-sensitive film 1 are positioned on the top points of the insulating film 3, the spiral coil 4 and the interdigital electrode 2. The flexible membrane 5 has an increased contact area with the interdigitated electrodes 2 and the sensor is more sensitive to the perception of ambient humidity. Meanwhile, the spiral coil 4 is wrapped by the bottom flexible film 5, so that the oxidization speed of the spiral coil 4 is reduced.
The humidity sensor provided by the utility model has a flexible multilayer structure, and the top layer humidity-sensitive film 1 is used as a humidity-sensitive layer and is fully contacted with the external environment directly, so that the quick response to humidity change is realized. The spiral coil 4, the insulating film 3 and the interdigital electrode 2 in the middle layer are used as conversion components for converting humidity parameters into electrical parameters, so that the structure is compact, and the response of the humidity-sensitive material to humidity can be quickly, sensitively and accurately converted into the change of LC resonance parameters. The flexible membrane 5 at the bottom of the sensor provides sufficient mechanical support for the entire sensor.
The humidity sensor is based on the circuit resonance and magnetic field coupling principle, has the advantages of small volume, long service life, softness, flexibility, simple structure, strong adaptability and good signal reproducibility, and can realize wireless detection of the ambient humidity in the closed space without any active element. Based on the advantages, the humidity sensor can overcome the defects of complexity and diversity of the traditional sensor application scene, is applied to nondestructive detection of humidity in environments such as rotation and sealing, and has wide development prospect in wireless sensor network construction.
Claims (7)
1. A flexible film humidity sensor, characterized by: the humidity sensor consists of a graphite alkyne and molybdenum disulfide composite humidity-sensitive film, an interdigital electrode, an insulating film, a spiral coil and a flexible film; the spiral coil and the interdigital electrode are respectively arranged at two sides of the insulating film and are connected through a through hole arranged on the insulating film; the humidity-sensitive film is covered on the interdigital electrode; the flexible film is arranged at the bottom of the sensor.
2. A flexible film humidity sensor as in claim 1 wherein said flexible film and humidity sensitive film are 40-50 mm in side length, said insulating film, spiral coil and interdigital electrode are 30-40 mm in side length, and said flexible film and humidity sensitive film side length center point is located on said insulating film, spiral coil and interdigital electrode top point.
3. The flexible thin film humidity sensor of claim 1 wherein: the humidity-sensitive film is composed of graphite alkyne and molybdenum disulfide composite materials, and is square in shape.
4. The flexible film humidity sensor of claim 1 wherein the humidity sensitive film is located on the top layer of the humidity sensor with a side length of 40-50 mm.
5. A flexible film humidity sensor as in claim 1 wherein said insulating film is Polyimide (PI) material, square in shape and 30-40 mm in side length.
6. A flexible film humidity sensor as in claim 1 wherein said spiral coil and interdigital electrode are copper or silver, square in shape and 30-40 mm on a side.
7. A flexible film humidity sensor as in claim 1 wherein said flexible film is of polyethylene terephthalate and is square in shape with sides of 40-50 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321226739.5U CN220084771U (en) | 2023-05-17 | 2023-05-17 | Flexible film humidity sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321226739.5U CN220084771U (en) | 2023-05-17 | 2023-05-17 | Flexible film humidity sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220084771U true CN220084771U (en) | 2023-11-24 |
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ID=88822016
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202321226739.5U Active CN220084771U (en) | 2023-05-17 | 2023-05-17 | Flexible film humidity sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN220084771U (en) |
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2023
- 2023-05-17 CN CN202321226739.5U patent/CN220084771U/en active Active
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