Positive temperature coefficient temperature sensor and manufacturing method thereof

Abstract

The invention relates to a positive temperature coefficient temperature sensor and a manufacturing method thereof. The manufacturing method comprises the following steps: S1, manufacturing an interdigital electrode; s2, preparing modified carbon black; s3, preparing a polypropylene-carbon black polymer; s4, preparing a polymer sheet; and S5, manufacturing the temperature sensor. The positive temperature coefficient temperature sensor has high temperature sensitivity, the polypropylene material has excellent corrosion resistance at the temperature of 80 DEG C or below, and the sensor has high sensitivity and linearity within the temperature range; in the physiological temperature range of the human body surface at the temperature of 30-45 DEG C, the linearity reaches 99.965% at most, and the temperature sensitivity reaches 0.6412% / DEG C, so that the problem of low stability of the existing temperature sensor is well solved.

Description

Technical Field

[0001] The invention relates to a method for manufacturing a temperature sensor, in particular to a positive temperature coefficient temperature sensor and a method for manufacturing the same. Background Art

[0002] In many industries, high-precision temperature measurement is essential. Small temperature deviations can cause problems such as inability to quickly control. Therefore, temperature sensors need to have characteristics such as high sensitivity, fast response, low cost and high reliability. Common temperature sensors are divided into three types: resistance temperature detectors, thermistors and thermocouples. The essence of thermistors is that the conductive path changes with temperature. When the temperature rises, the thermal expansion causes the conductive path formed by the conductive filler to break, resulting in increased resistance. The increase in resistance of conductive polymers with increasing temperature is defined as a positive temperature coefficient effect, and vice versa as a negative temperature coefficient effect. Compared with traditional temperature sensors made of metal, temperature sensors made of conductive polymer composites are corrosion-resistant, low-cost and easy to process.

[0003] Temperature coefficient materials are usually based on insulating polymers, with different types of conductive fillers added, such as metal powder, carbon black, carbon nanotubes, carbon fibers, graphite nanofibers, etc., to make them have a certain conductivity, and their resistance increases with the increase of temperature. This effect is widely used in the electronics industry, such as overcurrent protectors, self-regulating heaters, micro-switch sensors, etc. Among them, flexible wearable devices made based on temperature sensing characteristics show broad application prospects in human motion detection, real-time health detection, medical care, etc. Compared with other traditional materials, polymer materials with positive temperature coefficients have the advantages of good formability, good flexibility, light weight, high energy efficiency, and high safety. But at the same time, these positive temperature coefficient materials also have problems such as negative temperature coefficient effect during thermal cycling, weak repeatability, and poor mechanical properties. Therefore, the use of high-performance positive temperature coefficient materials to make temperature sensors still needs further exploration. Summary of the invention

[0004] The purpose of the present invention is to provide a positive temperature coefficient temperature sensor and a manufacturing method thereof, so as to solve the problem of low stability of existing temperature sensors.

[0005] The object of the present invention is achieved in that: A method for manufacturing a positive temperature coefficient temperature sensor comprises the following steps: S1. Making interdigital electrodes: prepare a polyimide film on a glass substrate, spin-coat a photoresist on the surface of the polyimide film, and transfer the pattern of the interdigital electrodes to the polyimide film by means of a mask; sputter electrodes on the polyimide film, remove attachments by ultrasound and cleaning, and form interdigital electrodes after drying.

[0006] S2. Preparation of modified carbon black: adding carbon black to titanate coupling agent solution at a mass ratio of 1:100, and making the titanate coupling agent uniformly adhere to the surface of carbon black particles through ultrasonic dispersion and stirring; centrifugally separating the carbon black and titanate coupling agent solution, and drying the separated solid at a constant temperature for 24 hours to obtain modified carbon black.

[0007] S3. Preparation of polypropylene-carbon black polymer: Put the modified carbon black and polypropylene in a ball mill at a ratio of 1:4-8 and grind for 1 hour to evenly disperse the carbon black in the polypropylene to obtain a polypropylene-carbon black polymer with a modified carbon black mass fraction of 12%-18%.

[0008] S4. Prepare polymer flakes: add polypropylene-carbon black polymer into a mold, heat it at 200° C. for 7 min to 10 min on a tablet press, and cool it to room temperature under a pressure of 800 N to 1300 N to obtain a polymer flake.

[0009] S5. Make a temperature sensor: Cover the polymer sheet on the interdigital electrodes and heat at 180°C for 3min~5min to soften the polymer sheet and fully contact the interdigital electrodes. After the polymer cools and solidifies, weld wires to the two electrodes of the interdigital electrodes respectively. After packaging, a positive temperature coefficient temperature sensor is obtained.

[0010] Furthermore, the titanate coupling agent solution used in step S2 is prepared by dispersing the titanate coupling agent CS-101 in isopropanol to prepare a solution with a mass fraction of 1% to 3%.

[0011] Furthermore, the constant temperature drying process in step S2 is to place the separated solid matter into a constant temperature oven and dry it at a constant temperature of 90° C. to 105° C. for 24 hours.

[0012] The purpose of the present invention can also be achieved like this: A positive temperature coefficient temperature sensor is manufactured according to the manufacturing method of the positive temperature coefficient temperature sensor of the present invention.

[0013] The advantages of the present invention are: 1. The material used for the positive temperature coefficient temperature sensor of the present invention is low in cost and has high stability, is corrosion-resistant at 80° C., and has a wide range of applications.

[0014] 2. The manufacturing method of the positive temperature coefficient temperature sensor of the present invention is simple, the manufacturing process is harmless, and the temperature sensor has good repeatability.

[0015] 3. The positive temperature coefficient temperature sensor of the present invention has high temperature sensitivity. The polypropylene material has excellent corrosion resistance below 80°C. The sensor has high sensitivity and linearity within this temperature range. Within the human body physiological temperature range of 30-45°C, the linearity reaches up to 99.965%, and the temperature sensitivity reaches 0.6412% / °C. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the positive temperature coefficient temperature sensor of the present invention.

[0017] Figure 2 The temperature-relative resistance variation curves of the temperature sensors obtained from the embodiments of the present invention and the comparative examples are shown.

[0018] Figure 3 It is the temperature-relative resistance change curve of the embodiment of the present invention in the range of 30-45°C.

[0019] Figure 4 The figures are the curves of the relative resistance change of the positive temperature coefficient temperature sensor made in each embodiment of the present invention during the cyclic heating process and the comparison diagram of the five maximum relative resistances; wherein (a) corresponds to embodiment 1, (b) corresponds to embodiment 2, (c) corresponds to embodiment 3, and (d) corresponds to embodiment 4. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0021] Embodiment 1: The manufacturing method of the positive temperature coefficient temperature sensor of this embodiment comprises the following steps: S1. Make interdigital electrodes: Spin-coat polyimide on a glass substrate, and adjust the rotation speed and time of the spin coater to control the thickness of the polyimide film to 20μm. Then, heat-bake and cure to obtain a polyimide film. Spin-coat photoresist on the surface of the polyimide film, control the rotation speed and time of the spin coater to make the thickness of the positive photoresist 3μm, and then soft-bake at 105°C for 1 minute to evaporate the solvent in the photoresist. Align the mask pattern with the polyimide film on the glass substrate, and transfer the pattern of the interdigital electrodes to the polyimide film by ultraviolet lithography and development. Sputter 200nm of copper on the polyimide film to form a copper electrode; then sputter a 50nm gold film on the surface of the copper electrode. The sputtered Au / Cu / PI interdigital electrode sample is placed in an acetone solution, and the photoresist on the electrode sample and the Au / Cu attached to the photoresist are removed in an ultrasonic cleaner; then ethanol and deionized water are used to clean the sample in an ultrasonic cleaner, and the electrode sheet removed from the glass substrate after drying is the interdigital electrode.

[0022] S2. Preparation of modified carbon black: first prepare a titanate coupling agent solution, disperse the titanate coupling agent CS-101 in isopropanol to prepare a solution with a mass fraction of 1%, and the ratio is: 1g of titanate coupling agent CS-101, 99g of isopropanol; thus, a titanate coupling agent solution is obtained. Then, carbon black is modified, and conductive carbon black is added to the prepared titanate coupling agent solution at a mass ratio of 1:100. First, ultrasonic dispersion is used for 2h, and then stirring is performed with a magnetic stirring device for 2h, so that the titanate coupling agent is evenly attached to the surface of the carbon black particles. The solution is separated by a centrifuge, and the separated solid is placed in a constant temperature oven and dried at a temperature of 105°C for 24h to obtain modified carbon black.

[0023] S3. Preparation of polypropylene-carbon black polymer: Place modified carbon black and polypropylene in a ball mill at a ratio of 1:7.3 (0.5 g of modified carbon black and 3.65 g of polypropylene), grind in a planetary ball mill at 200 rpm for 1 hour to evenly disperse the modified carbon black in the polypropylene, and obtain a polypropylene-carbon black polymer with a modified carbon black mass fraction of 12%.

[0024] S4. Preparation of polymer flakes: 5 mg of polypropylene-carbon black polymer was added to a mold, heated at 200° C. for 10 min on a tablet press, and slowly cooled to room temperature under a pressure of 800 N to obtain a polymer flake of a polypropylene-carbon black composite material.

[0025] S5. Make a temperature sensor: Cover the interdigital electrodes with a polymer sheet, place it on a heating table and heat it at 180°C for 3 minutes to soften the polymer sheet and allow it to fully contact the interdigital electrodes. After the polymer cools and solidifies, weld wires to the two electrodes of the interdigital electrodes, and then package them with polyimide tape to obtain a positive temperature coefficient temperature sensor.

[0026] like Figure 1 As shown, the positive temperature coefficient temperature sensor prepared by the manufacturing method of the present invention has the following structure: an interdigitated electrode 2 is formed on a polyimide film 1, a polymer sheet 3 formed by polymerizing and pressing polypropylene and carbon black is covered on the interdigitated electrode 2, wires are respectively welded on the two electrodes of the interdigitated electrode 2, and the polyimide film 1 is packaged by a polyimide tape 4, which is the positive temperature coefficient temperature sensor of the present invention.

[0027] Embodiment 2: The manufacturing method of the positive temperature coefficient temperature sensor of this embodiment comprises the following steps: S1. Making interdigital electrodes: same as in Example 1.

[0028] S2. Preparation of modified carbon black: first prepare a titanate coupling agent solution, disperse the titanate coupling agent CS-101 in isopropanol to prepare a solution with a mass fraction of 2%, and the ratio is: 1g of titanate coupling agent CS-101, 49g of isopropanol; thus, a titanate coupling agent solution is obtained. Then, carbon black is modified, and conductive carbon black is added to the prepared titanate coupling agent solution at a mass ratio of 1:100. First, ultrasonic dispersion is used for 2h, and then stirring is performed with a magnetic stirring device for 2h, so that the titanate coupling agent is evenly attached to the surface of the carbon black particles. The solution is separated by a centrifuge, and the separated solid is placed in a constant temperature oven and dried at a temperature of 100°C for 24h to obtain modified carbon black.

[0029] S3. Preparation of polypropylene-carbon black polymer: Place modified carbon black and polypropylene in a ball mill at a ratio of 1:6.15 (0.5 g of modified carbon black and 3.07 g of polypropylene), grind in a planetary ball mill at 200 rpm for 1 hour to evenly disperse the modified carbon black in the polypropylene, and obtain a polypropylene-carbon black polymer with a modified carbon black mass fraction of 14%.

[0030] S4. Preparation of polymer flakes: 5 mg of polypropylene-carbon black polymer was added to a mold, heated at 200° C. for 9 min on a tablet press, and slowly cooled to room temperature under a pressure of 900 N to obtain a polymer flake of a polypropylene-carbon black composite material.

[0031] S5. Make a temperature sensor: Cover the interdigital electrodes with a polymer sheet, place it on a heating table and heat it at 180°C for 4 minutes to soften the polymer sheet and fully contact the interdigital electrodes. After the polymer cools and solidifies, weld wires to the two electrodes of the interdigital electrodes respectively, and then package them with polyimide tape to obtain a positive temperature coefficient temperature sensor.

[0032] Embodiment 3: The manufacturing method of the positive temperature coefficient temperature sensor of this embodiment comprises the following steps: S1. Making interdigital electrodes: same as in Example 1.

[0033] S2. Preparation of modified carbon black: first prepare a titanate coupling agent solution, disperse the titanate coupling agent CS-101 in isopropanol to prepare a solution with a mass fraction of 3%, and the ratio is: 1g of titanate coupling agent CS-101, 32g of isopropanol; thus, a titanate coupling agent solution is obtained. Then, carbon black is modified, and conductive carbon black is added to the prepared titanate coupling agent solution at a mass ratio of 1:100. First, ultrasonic dispersion is used for 2h, and then stirring is performed with a magnetic stirring device for 2h, so that the titanate coupling agent is evenly attached to the surface of the carbon black particles. The solution is separated by a centrifuge, and the separated solid is placed in a constant temperature oven and dried at 90°C for 24h to obtain modified carbon black.

[0034] S3. Preparation of polypropylene-carbon black polymer: put modified carbon black and polypropylene in a ball mill at a ratio of 1:5.25 (0.5 g of modified carbon black and 2.63 g of polypropylene), grind in a planetary ball mill at 200 rpm for 1 hour to evenly disperse the modified carbon black in the polypropylene, and obtain a polypropylene-carbon black polymer with a modified carbon black mass fraction of 16%.

[0035] S4. Preparation of polymer flakes: 5 mg of polypropylene-carbon black polymer was added to a mold, heated at 200° C. for 8 min on a tablet press, and slowly cooled to room temperature under a pressure of 1100 N to obtain a polymer flake of a polypropylene-carbon black composite material.

[0036] S5. Make a temperature sensor: Cover the interdigital electrodes with a polymer sheet, place it on a heating table and heat it at 180°C for 5 minutes to soften the polymer sheet and allow it to fully contact the interdigital electrodes. After the polymer cools and solidifies, weld wires to the two electrodes of the interdigital electrodes, and then package them with polyimide tape to obtain a positive temperature coefficient temperature sensor.

[0037] Embodiment 4: The manufacturing method of the positive temperature coefficient temperature sensor of this embodiment comprises the following steps: S1. Making interdigital electrodes: same as in Example 1.

[0038] S2. Preparation of modified carbon black: first prepare a titanate coupling agent solution, disperse the titanate coupling agent CS-101 in isopropanol to prepare a solution with a mass fraction of 1%, and the ratio is: 1g of titanate coupling agent CS-101, 99g of isopropanol; thus, a titanate coupling agent solution is obtained. Then, carbon black is modified, and conductive carbon black is added to the prepared titanate coupling agent solution at a mass ratio of 1:100. First, ultrasonic dispersion is used for 2h, and then stirring is performed with a magnetic stirring device for 2h, so that the titanate coupling agent is evenly attached to the surface of the carbon black particles. The solution is separated by a centrifuge, and the separated solid is placed in a constant temperature oven and dried at a temperature of 105°C for 24h to obtain modified carbon black.

[0039] S3. Preparation of polypropylene-carbon black polymer: put modified carbon black and polypropylene in a ball mill at a ratio of 1:4.55 (0.5 g of modified carbon black and 2.28 g of polypropylene), grind in a planetary ball mill at 200 rpm for 1 hour to evenly disperse the modified carbon black in the polypropylene, and obtain a polypropylene-carbon black polymer with a modified carbon black mass fraction of 18%.

[0040] S4. Preparation of polymer flakes: 5 mg of polypropylene-carbon black polymer was added to a mold, heated at 200° C. for 7 min on a tablet press, and slowly cooled to room temperature under a pressure of 1300 N to obtain a polymer flake of a polypropylene-carbon black composite material.

[0041] S5. Make a temperature sensor: Cover the interdigital electrodes with a polymer sheet, place it on a heating table and heat it at 180°C for 5 minutes to soften the polymer sheet and allow it to fully contact the interdigital electrodes. After the polymer cools and solidifies, weld wires to the two electrodes of the interdigital electrodes, and then package them with polyimide tape to obtain a positive temperature coefficient temperature sensor.

[0042] Comparative Example 1 The preparation method of the positive temperature coefficient temperature sensor in this comparative example is basically the same as that in Example 1, except that there is no carbon black modification in step S2, but the conductive carbon black is directly filled into the polypropylene for polymerization. Specifically, polypropylene and carbon black are placed in a ball mill according to proportion, and ground at a speed of 200 rpm in a planetary ball mill for 1 hour to uniformly disperse the carbon black in the polypropylene to obtain a composite material of carbon black and polypropylene. Among them, the ratio used in the polypropylene-carbon black polymer is: 0.5g carbon black, 3.67g polypropylene; a polypropylene-carbon black polymer with a mass fraction of modified carbon black of 12% is prepared.

[0043] Comparative Example 2: The preparation method of the positive temperature coefficient temperature sensor in this comparative example is basically the same as that in Example 1, except that there is no carbon black modification in step S2, but the conductive carbon black is directly filled into the polypropylene for polymerization. Specifically, polypropylene and carbon black are placed in a ball mill according to proportion, and ground at a speed of 200 rpm in a planetary ball mill for 1 hour to uniformly disperse the carbon black in the polypropylene to obtain a composite material of carbon black and polypropylene. Among them, the ratio used in the polypropylene-carbon black polymer is: 0.5g carbon black, 3.07g polypropylene; a polypropylene-carbon black polymer with a mass fraction of modified carbon black of 14% is prepared.

[0044] Comparative Example 3: The preparation method of the positive temperature coefficient temperature sensor in this comparative example is basically the same as that in Example 1, except that there is no carbon black modification in step S2, but the conductive carbon black is directly filled into the polypropylene for polymerization. Specifically, polypropylene and carbon black are placed in a ball mill according to proportion, and ground at a speed of 200 rpm in a planetary ball mill for 1 hour to uniformly disperse the carbon black in the polypropylene to obtain a composite material of carbon black and polypropylene. Among them, the ratio used in the polypropylene-carbon black polymer is: 0.5g carbon black, 2.63g polypropylene; a polypropylene-carbon black polymer with a mass fraction of modified carbon black of 16% is prepared.

[0045] Comparative Example 4: The preparation method of the positive temperature coefficient temperature sensor in this comparative example is basically the same as that in Example 1, except that there is no carbon black modification in step S2, but the conductive carbon black is directly filled into the polypropylene for polymerization. Specifically, polypropylene and carbon black are placed in a ball mill according to proportion, and ground at a speed of 200 rpm in a planetary ball mill for 1 hour to uniformly disperse the carbon black in the polypropylene to obtain a composite material of carbon black and polypropylene. Among them, the ratio used in the polypropylene-carbon black polymer is: 0.5g carbon black, 2.28g polypropylene; a polypropylene-carbon black polymer with a mass fraction of modified carbon black of 18% is prepared.

[0046] Performance testing experiment: 1. Sensitivity The sensitivity of a temperature sensor is expressed by the temperature coefficient of resistance (TCR) and is defined by equation (1): (1) Among them, R1 and R0 correspond to the resistance of the sensor at work and room temperature (25°C), and T1 and T0 correspond to the temperature of the sensor at work and room temperature (25°C).

[0047] The temperature sensors obtained in Examples 1, 2, 3, 4 and Comparative Examples 1, 2, 3, 4 were taken as samples, and they were separately attached to a constant temperature heating table. The electrodes at both ends were connected with a multimeter, and the temperature change range of the heating table was adjusted to be 25°C to 80°C. The temperature of each temperature sensor was monitored in real time using a thermal imager. The resistance value displayed by the multimeter was read and recorded every 5°C, and a curve of temperature and resistance change rate was plotted. The results are shown in FIG. Figure 2 shown.

[0048] When the modified carbon black and unmodified carbon black in the temperature sensor are filled with mass fractions of 12%, 14%, 16%, and 18%, respectively, the sensor resistance increases with a positive temperature coefficient at a temperature change of 25°C to 80°C. Example 1 has the highest temperature sensitivity, with a resistance temperature coefficient of 0.669% / °C. As the mass fraction of carbon black increases from 12% to 18%, the temperature sensitivity of the sensor decreases. The carbon black-polypropylene polymer filled with modified carbon black has a higher temperature sensitivity than the carbon black-polypropylene polymer filled with unmodified carbon black.

[0049] 2. Temperature sensitivity of the sensor at 30-45℃ 30℃~45℃ covers the physiological temperature range of the human body surface. The temperature-sensitive properties of the sensor made of carbon black-polypropylene polymer filled with modified carbon black were studied within 30℃~45℃.

[0050] Take the temperature sensors obtained in Examples 1, 2, 3, and 4 as samples, attach them to a constant temperature heating table, connect the electrodes at both ends with a multimeter, adjust the temperature of the heating table to a range of 30°C to 45°C, use a thermal imager to monitor the temperature of the sensor in real time, read and record the resistance value displayed by the multimeter every 1°C, and draw a curve of temperature and resistance change rate. The results are as follows: Figure 3 As shown. As the temperature increases, the resistance of the sensor gradually increases. The change of resistance with temperature is fitted by curve fitting. The composite materials with different modified carbon black filling mass fractions all show linear changes. The linearity of the four groups of samples is above 99.5%, among which the sensor obtained in Example 2 has the highest linearity, which is as high as 99.965%. High linearity means that the sensor can provide an accurate and reliable relationship between temperature and resistance, and can be used to monitor body surface temperature within the physiological temperature range of the human body surface.

[0051] 3. Repeatability The temperature sensors prepared in Examples 1, 2, 3, and 4 were subjected to temperature cycle tests to investigate their repeatability and stability. Figure 4 As shown in the figure, the relative resistance change curve of the temperature sensor during the five cycles of heating at 30-45°C and the comparison of the five maximum relative resistances show that the resistance of the temperature sensor shows a reversible change during the cycle test, but the sensor resistance fluctuates to a certain extent each time. Figure 4 As shown in (a), when the mass fraction of CB-1 is 12%, the fluctuation of the maximum resistance of the sensor is the largest, which is 1.34%. Figure 4 As shown in (b), the fluctuation of the maximum resistance of the sensor is the smallest, which is 0.26%. At the same time, during the five cycles of heating, when the mass fraction of CB-1 is 14%, the stability of the sensor resistance change is the highest compared to other mass fractions. This shows that the temperature sensor made of the composite material filled with 14% CB-1 has high repeatability and stability. At the same time, CB-1 / PP has strong corrosion resistance within 80°C, and can better adapt to the weak acid environment of human body sweat, providing more possibilities for human body surface temperature detection.

Claims

1. A method for manufacturing a positive temperature coefficient temperature sensor, characterized in that: The following steps are involved: S1. Making interdigital electrodes: preparing a polyimide film on a glass substrate, spin-coating a photoresist on the surface of the polyimide film, and transferring the pattern of the interdigital electrodes to the polyimide film by means of a mask; sputtering electrodes on the polyimide film, removing attachments by ultrasonication and cleaning, and drying to form interdigital electrodes; S2. Preparation of modified carbon black: adding carbon black to a titanate coupling agent solution at a mass ratio of 1:100, and dispersing and stirring the titanate coupling agent by ultrasonic wave to make the titanate coupling agent uniformly adhere to the surface of carbon black particles; centrifugally separating the carbon black and the titanate coupling agent solution, and drying the separated solid at a constant temperature for 24 hours to obtain modified carbon black; S3. Preparation of polypropylene-carbon black polymer: Put modified carbon black and polypropylene in a ball mill at a ratio of 1:4-8 and grind for 1 hour to make the carbon black evenly dispersed in the polypropylene to obtain a polypropylene-carbon black polymer with a modified carbon black mass fraction of 12%-18%; S4, preparing a polymer sheet: adding a polypropylene-carbon black polymer into a mold, heating it at 200° C. for 7 min to 10 min on a tablet press, and cooling it to room temperature under a pressure of 800 N to 1300 N to obtain a polymer sheet; S5. Make a temperature sensor: Cover the polymer sheet on the interdigital electrodes and heat at 180°C for 3min~5min to soften the polymer sheet and fully contact the interdigital electrodes. After the polymer cools and solidifies, weld wires to the two electrodes of the interdigital electrodes respectively. After packaging, a positive temperature coefficient temperature sensor is obtained.

2. The method for manufacturing a positive temperature coefficient temperature sensor according to claim 1, characterized in that: The titanate coupling agent solution used in step S2 is prepared by dispersing the titanate coupling agent CS-101 in isopropanol to prepare a solution with a mass fraction of 1% to 3%.

3. The method for manufacturing a positive temperature coefficient temperature sensor according to claim 1, characterized in that: The constant temperature drying process in step S2 is to place the separated solid matter into a constant temperature oven and dry it at a constant temperature of 90° C. to 105° C. for 24 hours.

4. A positive temperature coefficient temperature sensor, characterized in that: The positive temperature coefficient temperature sensor is manufactured according to the manufacturing method of any one of claims 1 to 3.

Images