Resistance-type flexible temperature sensor device and preparation method thereof

Abstract

The invention discloses a resistive flexible temperature sensor device and a preparation method thereof, and the method comprises the steps: dispersing graphene conductive ink in a homogenizer at a rotating speed of not less than 1000 r / min to obtain uniformly dispersed graphene conductive ink; copper welding spots are arranged at the two ends of the flexible substrate, the flexible substrate is placed on an operation platform, the operation platform is placed on a silk-screen printing table, graphene conductive ink is evenly coated on the silk-screen printing table for printing, and the obtained flexible substrate with the graphene temperature-sensitive film is placed on a constant-temperature heating table at the temperature of 90-160 DEG C to be dried for 40 min to 2 h; a wire connected with a processor is welded at the copper welding point, and the processor is used for obtaining a temperature value according to the collected voltage value. According to the invention, the wearing comfort is good, and good temperature sensing characteristics and high response speed can be shown in a human body temperature range.

Description

Technical Field

[0001] The present invention relates to the field of flexible electronics and temperature sensing, and in particular to a resistive flexible temperature sensor device and a preparation method thereof. Background Art

[0002] At present, aging has become a common phenomenon around the world. Faced with the severe aging situation, people have begun to realize that the response to diseases should shift from timely treatment to timely prevention. Temperature sensors that can monitor human body conditions anytime and anywhere have emerged.

[0003] In recent years, the field of flexible electronics has developed rapidly, providing technical support for the manufacture of flexible sensors. In the field of health monitoring, flexible sensors have better wearing comfort and play a positive role in daily monitoring of human health status.

[0004] In order to connect with communication equipment, realize real-time information exchange, better fit with skin, more comfortable, and provide more possibilities for personalized health management and physical condition monitoring of more special groups, it is necessary to develop a flexible temperature sensor for body temperature measurement. Some current temperature sensors are hard or take a long time to measure, which has great deficiencies in user experience and efficiency. Summary of the invention

[0005] In view of the shortcomings of the prior art such as poor wearing comfort and long response time, the present invention proposes a resistive flexible temperature sensor device and a preparation method thereof, which has the advantages of simple production, low cost, short response time and good wearing comfort.

[0006] The specific technical solutions are as follows:

[0007] A method for preparing a resistive flexible temperature sensor device, comprising:

[0008] S1: dispersing the graphene conductive ink in a homogenizer at a speed of not less than 1000 r / min to obtain a uniformly dispersed graphene conductive ink;

[0009] S2: copper soldering points are arranged at both ends of the flexible substrate, the positions of the copper soldering points correspond to the ends of the pattern to be screen-printed, and the flexible substrate is placed on an operating platform;

[0010] S3: Place the operating platform on the screen printing table and assemble the screen printing plate;

[0011] S4: evenly coating the graphene conductive ink on one side of the screen printing plate, performing a printing operation, and obtaining a printed flexible substrate with a graphene temperature-sensitive film;

[0012] S5: placing the flexible substrate with the graphene temperature-sensitive film on a constant temperature heating table for drying, the temperature of the constant temperature heating table is 90° C.-160° C., and the drying time is 40 minutes-2 hours;

[0013] S6: A wire connected to a processor is welded at the copper welding point, and the processor is used to obtain a temperature value according to the collected voltage value.

[0014] Furthermore, in S3, the screen printing plate has a specific pattern, and the specific pattern includes: a straight line, a serpentine, and a circle.

[0015] Furthermore, the screen printing plate is a 120T screen plate.

[0016] Furthermore, the operating platform adopts a glass substrate.

[0017] Furthermore, in S1, the time range for dispersing the graphene conductive ink at a set rotation speed is more than 1 minute.

[0018] A resistive flexible temperature sensor device is prepared according to the preparation method of the resistive flexible temperature sensor device, comprising: a flexible substrate, a graphene temperature-sensitive film, and a wire; the material of the flexible substrate is polyimide, the graphene temperature-sensitive film is arranged on the flexible substrate, and copper soldering points are arranged at corresponding positions of both ends of the flexible substrate, one end of the wire is welded to the copper soldering point, and the other end is connected to a processor for connecting the graphene temperature-sensitive film to the processor; the processor is used to process the collected voltage value to obtain a temperature value.

[0019] Furthermore, the thickness of the flexible substrate is 25 μm.

[0020] Furthermore, the shapes of the graphene temperature-sensitive film include: linear, serpentine, and circular.

[0021] Furthermore, the line widths of the three shapes of graphene temperature-sensitive films are all 0.1 cm, and the interval between each line of the serpentine and circular graphene temperature-sensitive films is 0.15 cm.

[0022] The beneficial effects of the present invention are:

[0023] (1) The resistive flexible temperature sensor device prepared by the present invention has good flexibility, simple and compact structure, and is comfortable and convenient to wear; on the other hand, based on the temperature-sensitive properties of graphene, it can exhibit good temperature sensing properties and a faster response speed within the human body temperature range.

[0024] (2) The resistive flexible temperature sensor device prepared by the present invention has a simple structure and a convenient manufacturing process, which can reduce manufacturing costs and is suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a top view of a linear resistive flexible temperature sensor device in an embodiment of the present invention.

[0026] Figure 2 is a side view of a linear resistive flexible temperature sensor device in an embodiment of the present invention.

[0027] Figure 3 1 is a top view of a serpentine resistive flexible temperature sensor device according to an embodiment of the present invention.

[0028] Figure 4 is a top view of a circular resistive flexible temperature sensor device in an embodiment of the present invention.

[0029] Figure 5 1 is a flow chart of a method for preparing a resistive flexible temperature sensor device in an embodiment of the present invention.

[0030] Figure 6 Schematic diagram of the temperature-voltage inverse proportional fitting curve of the linear resistive flexible temperature sensor device in an embodiment of the present invention.

[0031] Figure 7 3 is a temperature curve diagram of the linear resistive flexible temperature sensor device according to the embodiment of the present invention measured in a 40° C. environment.

[0032] In the figure, there is a flexible substrate 1, a graphene temperature-sensitive film 2, and a conductor 3. DETAILED DESCRIPTION

[0033] The present invention will be described in detail below according to the accompanying drawings and preferred embodiments, and the purpose and effect of the present invention will become more clear. The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] like Figure 1 and Figure 2 As shown, a resistive flexible temperature sensor device includes: a flexible substrate 1, a graphene temperature-sensitive film 2, and a wire 3. The flexible substrate 1 is in the shape of a flat plate, and its size is set according to actual needs. The material of the flexible substrate 1 is polyimide. The graphene temperature-sensitive film 2 is arranged on the flexible substrate 1, and copper soldering points are arranged at both ends of the graphene temperature-sensitive film 2 at corresponding positions on the flexible substrate 1. One end of the wire 3 is welded to the copper soldering point, and the other end is connected to the processor, which is used to connect the graphene temperature-sensitive film 2 to the processor; the processor is used to process the collected voltage value to obtain the temperature value.

[0035] The shapes of the graphene temperature-sensitive film 2 include: linear, serpentine, and circular. The linear graphene temperature-sensitive film 2 is as follows: Figure 1As shown in FIG. 2 , the line width is d1 = 0.1 cm, and the dimensions of the two ends are enlarged to match the copper solder joints. Figure 3 As shown, the continuous film line is repeatedly bent back and forth to form a rectangular graphene temperature-sensitive film 2. The contact area between the resistor and the heat source is increased by bending. The line width is d1 = 0.1 cm, and the interval between each line is d2 = 0.15 cm. The size of the two ends is enlarged to match the copper soldering point. The circular graphene temperature-sensitive film 2 is as shown in FIG. Figure 4 As shown, the continuous film line is repeatedly bent back and forth to form a circular graphene temperature-sensitive film 2. The contact area between the resistor and the heat source is increased by bending. The line width is d1 = 0.1 cm, and the interval between each line is d2 = 0.15 cm. The size of the two ends is enlarged to match the copper welding point.

[0036] like Figure 5 As shown, a method for preparing a resistive flexible temperature sensor device specifically comprises the following steps:

[0037] S1: Disperse the graphene conductive ink in a homogenizer at a speed of at least 1000 r / min for at least one minute to obtain a uniformly dispersed graphene conductive ink. In this embodiment, the speed is 1000 r / min for one minute. If the speed is lower than this, the graphene may be unevenly dispersed in the ink, affecting the conductivity.

[0038] S2: Copper soldering points are set at both ends of the flexible substrate 1, and the positions of the copper soldering points correspond to the ends of the pattern to be screen-printed, and the flexible substrate 1 is placed on an operating platform; in this embodiment, the thickness of the flexible substrate 1 is 25 μm, and the operating platform is preferably a glass substrate, and the size of the glass substrate is 70 mm × 70 mm × 1 mm; the size of the linear flexible substrate 1 is 1.5 cm × 5 cm × 25 μm, and the size of the serpentine and circular flexible substrates 1 are both 5 cm × 5.5 cm × 25 μm.

[0039] S3: Place the operating platform on the screen printing table and assemble a screen printing plate with a specific pattern. The specific patterns include straight lines, snakes, and circles, which can be selected according to actual needs; the screen printing plate uses a 120T screen to ensure printing accuracy. If a screen larger than 120T is used, it is easy for the ink to leak from the screen, thus failing to form a pattern; if a screen smaller than 120T is used, the printed shape is easy to be unclear and mushy.

[0040] S4: evenly apply the graphene conductive ink obtained in S1 on one side of the screen printing plate to ensure that the ink is evenly distributed; then, perform a printing operation to obtain a printed flexible substrate 1 with a graphene temperature-sensitive film 2.

[0041] S5: placing the flexible substrate 1 with the graphene temperature-sensitive film 2 on a constant temperature heating table for drying, the temperature of the constant temperature heating table is 90°C-160°C, and the drying time is 40 minutes-2 hours to ensure that the ink is completely cured. Lowering the temperature will prolong the drying time. From the perspective of ensuring efficiency, in this embodiment, 90°C is selected for drying for two hours.

[0042] S6: Welding wires 3 to the copper welding points at both ends of the graphene temperature-sensitive film 2 obtained in S5, and connecting the other end of the wires 3 to the processor to form a resistive flexible temperature sensor device, the structure of which from top to bottom is a graphene temperature-sensitive film 2, a wire 3, and a flexible substrate 1.

[0043] In practical applications, the prepared resistive flexible temperature sensor device can be used for real-time measurement and display of human body temperature.

[0044] The working principle of the resistive flexible temperature sensor device is: heat will be transferred from the part in contact with the graphene temperature-sensitive film 2 to the graphene temperature-sensitive film 2, resulting in a change in the material temperature. According to the relationship between the resistance and temperature of the graphene material, it can be approximated as a negative proportional linear relationship, and this temperature change will affect the resistance value of the material. When connected to a suitable voltage divider circuit, it can be deduced that the temperature value and the voltage value have an inverse proportional function relationship based on the mathematical relationship between the resistance value and the voltage value of the sensor, and then it can be converted to infer the temperature of the contact part through the change in the voltage value.

[0045] Working process: The side of the temperature sensor printed with the graphene temperature-sensitive film 2 is attached to the human body surface, and two wires are connected to the lower computer (i.e., the processor). The collected voltage value is filtered by sliding window, and the measured real-time temperature value is calculated based on the inverse proportional mathematical relationship between the temperature value and the voltage value and sent to the upper computer. The upper computer, i.e., the user interface, will display the measured temperature value and the temperature curve. When the graphene temperature-sensitive film 2 of the resistive flexible temperature sensor device is linear, its temperature-voltage inverse proportional fitting curve is as follows: Figure 6 As shown in the figure, the fitting relationship is good, which shows that the temperature sensor of the present invention meets the theoretical relationship between the measured temperature value and the sensor voltage value as an inverse proportional function, and can more accurately calculate the temperature value through the voltage value. When the graphene temperature-sensitive film 2 of the resistive flexible temperature sensor device is a straight line, the temperature curve measured in a 40°C environment is as follows: Figure 7 As shown in the figure, it can be seen that the measurement accuracy of the resistive flexible temperature sensor device prepared by the method of the present invention is high, the error is within 0.5%, and the measurement data is stable without too much fluctuation.

[0046] Those skilled in the art can understand that the above are only preferred examples of the invention and are not intended to limit the invention. Although the invention is described in detail with reference to the above examples, those skilled in the art can still modify the technical solutions recorded in the above examples or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, etc. made within the spirit and principle of the invention shall be included in the protection scope of the invention.

Claims

1. A method for preparing a resistive flexible temperature sensor device, characterized in that: include: S1: dispersing the graphene conductive ink in a homogenizer at a speed of not less than 1000 r / min to obtain a uniformly dispersed graphene conductive ink; S2: copper soldering points are arranged at both ends of the flexible substrate, the positions of the copper soldering points correspond to the ends of the pattern to be screen-printed, and the flexible substrate is placed on an operating platform; S3: Place the operating platform on the screen printing table and assemble the screen printing plate; S4: evenly coating the graphene conductive ink on one side of the screen printing plate, performing a printing operation, and obtaining a printed flexible substrate with a graphene temperature-sensitive film; S5: placing the flexible substrate with the graphene temperature-sensitive film on a constant temperature heating table for drying, the temperature of the constant temperature heating table is 90° C.-160° C., and the drying time is 40 minutes-2 hours; S6: A wire connected to a processor is welded at the copper welding point, and the processor is used to obtain a temperature value according to the collected voltage value.

2. The method for preparing a resistive flexible temperature sensor device according to claim 1, characterized in that: In S3, the screen printing plate has a specific pattern, and the specific pattern includes: a straight line, a serpentine, and a circle.

3. The method for preparing a resistive flexible temperature sensor device according to claim 1, characterized in that: The screen printing plate is a 120T screen.

4. The method for preparing a resistive flexible temperature sensor device according to claim 1, characterized in that: The operating platform adopts a glass substrate.

5. The method for preparing a resistive flexible temperature sensor device according to claim 1, characterized in that: In S1, the time range for dispersing the graphene conductive ink at a set rotation speed is more than 1 minute.

6. A resistive flexible temperature sensor device, prepared according to the method for preparing a resistive flexible temperature sensor device according to any one of claims 1 to 5, characterized in that: include: Flexible substrate, graphene temperature-sensitive film, and conductor; The material of the flexible substrate is polyimide, and the graphene temperature-sensitive film is arranged on the flexible substrate. Copper welding points are set at corresponding positions on both ends of the flexible substrate. One end of the wire is welded on the copper welding point, and the other end is connected to the processor, which is used to connect the graphene temperature-sensitive film to the processor; the processor is used to process the collected voltage value to obtain the temperature value.

7. The resistive flexible temperature sensor device according to claim 6, characterized in that: The thickness of the flexible substrate is 25 μm.

8. The resistive flexible temperature sensor device according to claim 6, characterized in that: The shapes of the graphene temperature-sensitive film include: straight line, serpentine, and circular.

9. The resistive flexible temperature sensor device according to claim 8, characterized in that: The line width of the three shapes of graphene temperature-sensitive films is 0.1 cm, and the interval between each line of the serpentine and circular graphene temperature-sensitive films is 0.15 cm.

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