Portable disposable passive humidity sensor

Abstract

The invention discloses a portable disposable passive humidity sensor which comprises a humidity response heating material used for reacting with water vapor in the environment, and the humidity response heating material is arranged on a breathable film. A heat conduction film used for covering the humidity response heating material and the breathable film is arranged above the breathable film, the heat conduction film is used for transmitting heat generated by the humidity response heating material, temperature test paper is arranged above the heat conduction film, temperature display and temperature-sensitive ink is printed on the temperature test paper, and the temperature display and temperature-sensitive ink is printed on the breathable film. The temperature-sensitive ink is irreversible color-changing ink. The humidity response heating material is heated when encountering water vapor, the color-changing temperature-sensitive ink is activated to change color, and the value of the temperature-sensitive test paper is read to determine the humidity. The device has the advantages of being disposable, portable, accurate in measurement, free of influence of environment temperature and the like, and an external power supply is not needed for power supply.

Description

Technical Field

[0001] The invention relates to the technical field of humidity sensors, and in particular to a portable disposable passive humidity sensor. Background Art

[0002] Humidity is an important environmental parameter in production and life. Humidity sensors, as an important tool for monitoring and controlling humidity, are widely used in agricultural production, environmental monitoring, industrial production, and medical care. In order to meet the demand for humidity sensors in the intelligent era, high-performance humidity sensors with high sensitivity, good stability, fast test speed, and low cost are urgently needed.

[0003] As the core component of humidity sensors, humidity-sensitive materials play a vital role in the performance of sensors. The characteristics of humidity-sensitive materials directly affect the sensitivity, accuracy and stability of humidity sensors. Ideal humidity-sensitive materials should have fast response speed, high sensitivity, good stability and linear response to humidity changes.

[0004] According to different measurement principles, common humidity sensors can be divided into the following categories:

[0005] 1. Resistive humidity sensor: This sensor is usually made of hygroscopic materials. When the ambient humidity changes, the resistance of the material will also change. By measuring the change in resistance, the humidity can be determined. Its advantages are simple structure and low cost. Its disadvantages are the need for an external power supply, temperature dependence, and durability issues.

[0006] 2. Capacitive humidity sensor: It uses the effect of humidity on the dielectric constant between the capacitor plates to measure humidity. When the humidity increases, the dielectric constant increases and the capacitance value also increases. Its advantages are more linear response, high sensitivity and low power consumption compared to resistive sensors. Its disadvantages are that it is easily affected by impurities, requires regular calibration, is expensive, and is sensitive to high-frequency signals.

[0007] 3. Thermal conductivity humidity sensor: Determines humidity based on measuring the thermal conductivity of air. The higher the humidity, the lower the thermal conductivity of air, and the sensor can measure humidity by detecting this change. Its advantages are that it is less affected by temperature and is suitable for high humidity environments. Its disadvantages are relatively low accuracy, high energy consumption (requires heating elements), and limited range.

[0008] 4. Infrared humidity sensor: It uses the absorption or reflection characteristics of infrared to detect humidity. Infrared of a specific wavelength will be absorbed by water molecules. By measuring the intensity change of infrared, humidity information can be obtained indirectly. Its advantages are non-contact measurement, fast response, and high precision. Its disadvantages are that it is affected by the environment (dust, smoke, light, etc.), sensitive to the applicable ambient temperature, and high cost.

[0009] The above humidity sensors are relatively common in the market, but their advantages and disadvantages are also obvious. For example, most sensors require an external power supply and cannot be used in some scenarios where power cannot be provided, such as outdoors, tunnels, etc.; at the same time, most humidity sensors need to be used within room temperature, and their use is limited in some high-altitude or cold areas; they cannot be compatible with passive, high-precision, high-sensitivity, portable and low-cost characteristics at the same time. Summary of the invention

[0010] The object of the present invention is to provide a portable disposable passive humidity sensor.

[0011] To achieve the above object, the present invention provides the following technical solutions:

[0012] A portable, disposable passive humidity sensor comprises a humidity-responsive heating material for reacting with water vapor in the environment, the humidity-responsive heating material is arranged on a breathable film, a heat-conductive film for covering the humidity-responsive heating material and the breathable film is arranged above the breathable film, the heat-conductive film is used to transfer the heat generated by the humidity-responsive heating material, a temperature test paper is arranged above the heat-conductive film, a temperature display and temperature-sensitive ink are printed on the temperature test paper, and the temperature-sensitive ink is an irreversible color-changing ink.

[0013] Preferably, a waterproof layer is provided below the breathable film to cover the bottom of the breathable film.

[0014] Preferably, the area of ​​the humidity-responsive heat-generating material is smaller than the area of ​​the breathable film, and the humidity-responsive heat-generating material is arranged in the middle of the breathable film.

[0015] Preferably, the position of the temperature sensitive ink corresponds to the position of the humidity responsive heat generating material.

[0016] Preferably, the material of the breathable film is at least one of polyester fiber, polyester fiber and nylon.

[0017] Preferably, the material of the thermally conductive film is at least one of copper foil, zinc oxide and carbon nanotubes.

[0018] Preferably, the waterproof layer is made of PET, and a glue layer is provided on one side of the waterproof layer close to the breathable film.

[0019] The beneficial effects of the present invention are as follows: the present invention utilizes the humidity-responsive heating material to generate heat when it encounters water vapor, activates the color-changing temperature-sensitive ink to change color, and reads the value of the temperature-sensitive test paper to determine the humidity. The present invention has the advantages of disposable use, portability, no need for external power supply, accurate measurement, and no influence of ambient temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structural principle of the present invention;

[0021] Figure 2 It is a schematic diagram of the structure of the present invention;

[0022] Figure 3 It is a front view structural schematic diagram of the present invention;

[0023] Among them: humidity responsive heating material 1, breathable film 2, thermal conductive film 3, temperature test paper 4, temperature sensitive ink 5, temperature display 6, waterproof layer 7. DETAILED DESCRIPTION

[0024] The technical solution of this patent is further described in detail below in conjunction with specific implementation methods.

[0025] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "top", "bottom", "upper", "lower", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0026] like Figure 1 to Figure 2 As shown, a portable, disposable passive humidity sensor includes a humidity-responsive heating material 1 for reacting with water vapor in the environment. The humidity-responsive heating material 1 of the present invention may be, for example, carbon nanotubes, metal oxides, polymer electrolytes, etc., so long as they can achieve their functions. These materials can generate heat when the humidity changes. Furthermore, the humidity-responsive heating material 1 is disposed on a breathable film 2, the area of ​​the humidity-responsive heating material 1 is smaller than the area of ​​the breathable film 2, and the humidity-responsive heating material 2 is disposed in the middle of the breathable film 2. The material of the breathable film 2 of the present invention is at least one of polyester fiber, polyester fiber, nylon, etc. When in use, water vapor in the environment passes through the breathable film 2 to react with the humidity-responsive heating material 1, causing the temperature of the humidity-responsive heating material 1 to rapidly rise to a peak value.

[0027] A heat-conductive film 3 is provided above the breathable film 2 to cover the humidity-responsive heating material 1 and the breathable film 2. The material of the heat-conductive film 3 of the present invention is at least one of copper foil, zinc oxide, carbon nano-materials, etc. The heat-conductive film 3 is used to transfer the heat generated by the humidity-responsive heating material 1 to the temperature-sensitive ink 5 above the heat-conductive film 3.

[0028] Furthermore, a temperature test paper 4 is arranged above the thermally conductive film 3, and the temperature test paper 4 is printed with a temperature-sensitive ink 5. The function of the temperature-sensitive ink 5 is to intuitively display the heat change. The temperature-sensitive ink has two types: reversible and irreversible. The present invention selects irreversible temperature-sensitive color-changing ink, which can distinguish 8 different temperatures. The surface of the temperature test paper 4 is also provided with a temperature display 6, which can display the specific temperature. The temperature test paper 4 is arranged on the top layer of the present invention, which is a special corresponding card, and displays the ambient humidity through the precise correspondence between the humidity and temperature of the humidity-responsive heating material 1. The position of the temperature-sensitive ink 5 corresponds to the position of the humidity-sensitive response heating material 1, so that the temperature generated by the humidity-sensitive response heating material 1 activates the color-changing temperature-sensitive ink 5 to change color, and more accurately reflects the humidity of the environment.

[0029] Furthermore, a waterproof layer 7 is provided below the breathable film 2 to cover the bottom of the breathable film 2. The material of the waterproof layer 7 can be a material such as PET that can achieve the above functions. A glue layer (not shown) for adhering the waterproof layer 7 to the breathable film 2 is provided near the breathable film 2. The waterproof layer 7 is adhered to the bottom of the breathable film 2, and can isolate the humidity responsive heating material 1 above the breathable film 2 from the external environment.

[0030] When the present invention is used, the waterproof layer 7 arranged at the bottom is firstly torn off, and the humidity-responsive heating material 1 will react with the water vapor in the environment. Then, the temperature of the humidity-responsive heating material 1 rises rapidly to a peak value, and the heat generated thereby activates the color-changing temperature-sensitive ink 5 to change color. Finally, the value of the color-changing grid on the temperature display is read to determine the humidity.

[0031] The present invention has the advantages of disposable, portable, no need for external power supply, accurate measurement, and no influence of ambient temperature, etc. Therefore, it has good application prospects, such as some places where power cannot be provided, such as coal mine tunnels, granaries, etc., and can also be used by mountaineers or extreme sports in high altitude or cold areas.

[0032] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0033] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A portable, disposable passive humidity sensor, characterized in that: It includes a humidity-responsive heating material for reacting with water vapor in the environment, the humidity-responsive heating material is arranged on a breathable film, a heat-conductive film for covering the humidity-responsive heating material and the breathable film is arranged above the breathable film, the heat-conductive film is used to transfer the heat generated by the humidity-responsive heating material, a temperature test paper is arranged above the heat-conductive film, the temperature test paper is printed with a temperature display and temperature-sensitive ink, and the temperature-sensitive ink is an irreversible color-changing ink.

2. The portable disposable passive humidity sensor according to claim 1, characterized in that: A waterproof layer is arranged below the breathable film to cover the bottom of the breathable film.

3. The portable disposable passive humidity sensor according to claim 2, characterized in that: The area of ​​the humidity-responsive heat-generating material is smaller than the area of ​​the breathable film, and the humidity-responsive heat-generating material is arranged in the middle of the breathable film.

4. The portable disposable passive humidity sensor according to claim 3, characterized in that: The position of the temperature-sensitive ink corresponds to the position of the humidity-responsive heat-generating material.

5. The portable disposable passive humidity sensor according to claim 1, characterized in that: The material of the breathable film is at least one of polyester fiber, terylene fiber and nylon.

6. The portable disposable passive humidity sensor according to claim 1, characterized in that: The material of the thermal conductive film is at least one of copper foil, zinc oxide and carbon nanotubes.

7. The portable disposable passive humidity sensor according to claim 1, characterized in that: The material of the waterproof layer is PET, and a glue layer is arranged on the side of the waterproof layer close to the breathable film.

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