Distributed flexible temperature-sensitive sensor array and method of making same

Abstract

This invention discloses a distributed flexible temperature-sensitive sensor array and its fabrication method. The distributed flexible temperature-sensitive sensor array includes: a first electrode layer, a first protective layer, a second electrode layer, a second protective layer, a temperature-sensitive sensing layer, and a thermally conductive layer, sequentially stacked along a selected direction. The first electrode layer includes at least one first electrode, and the first electrode includes multiple first conductive contacts, which are spaced apart and connected in series along a first direction. The second electrode includes multiple second conductive contacts, which are spaced apart and connected in series along a third direction. Both the first and second conductive contacts are electrically connected to the temperature-sensitive sensing layer. The temperature-sensitive sensing layer, a first conductive contact, and a second conductive contact form a sensing unit, wherein the first direction intersects with the third direction. The flexible temperature-sensitive sensor provided by this invention has high measurement accuracy, high stability, and good reliability.

Description

Technical Field

[0001] This invention relates to a distributed flexible temperature-sensitive sensor array and its fabrication method, belonging to the field of sensor technology. Background Technology

[0002] Temperature sensors play a crucial role in monitoring and sensing ambient temperature. Currently, commercially available temperature sensors mainly include resistance temperature detectors (RTDs), thermocouples, and resistance thermometers. However, these traditional rigid temperature sensors have drawbacks such as being inflexible and having a large size, making them unsuitable for applications involving temperature measurement on irregular surfaces and in confined spaces. Furthermore, these traditional rigid temperature sensors are generally only suitable for single-point temperature detection, which greatly limits their application in large-area, multi-point distributed temperature detection.

[0003] With the rapid development of flexible electronic devices, the research on flexible temperature sensors has gradually deepened. The flexible temperature sensors prepared in the early stage based on materials such as liquid metal, silver nanowires, and copper nanowires still have defects such as high cost and high sintering temperature. There is still obvious room for improvement in terms of stability and miniaturization. Summary of the Invention

[0004] The main objective of this invention is to provide a distributed flexible temperature sensor array and its preparation method. The distributed flexible temperature sensor array is flexible and thin, enabling distributed temperature detection over a large area and at multiple points. The nano-flexible composite temperature-sensitive material prepared using in-situ synthesis technology has high stability and reliability of the network structure. It is not only applicable to the application scenarios of currently commercially available rigid temperature sensors, but can also be widely used for temperature measurement on irregular surfaces and in narrow spaces, thereby overcoming the shortcomings of existing technologies.

[0005] To achieve the aforementioned objectives, the technical solution adopted by this invention includes: This invention provides a distributed flexible temperature sensor array, comprising a first electrode layer, a first protective layer, a second electrode layer, a second protective layer, a temperature sensing layer, and a thermally conductive layer sequentially stacked along a selected direction. The first electrode layer includes at least one first electrode, and the first electrode includes a plurality of first conductive contacts. The plurality of first conductive contacts are spaced apart along a first direction and connected in series. The second electrode includes a plurality of second conductive contacts. The plurality of second conductive contacts are spaced apart along a third direction and connected in series. The first conductive contacts and the second conductive contacts are both electrically connected to the temperature-sensitive sensing layer. The temperature-sensitive sensing layer, a first conductive contact, and a second conductive contact form a sensing unit, wherein the first direction intersects the third direction.

[0006] Furthermore, the first electrode layer includes a plurality of first electrodes, which are arranged sequentially at intervals along a second direction, the second direction intersecting the first direction, and the second direction being parallel to or intersecting the third direction.

[0007] Furthermore, any two of the first electrodes are electrically isolated.

[0008] Furthermore, the plurality of first electrodes are arranged in parallel.

[0009] Furthermore, in the second direction, the distribution density of the first electrode is above 5 electrodes / cm.

[0010] Furthermore, the second electrode layer includes a plurality of second electrodes, which are arranged sequentially at intervals along a fourth direction, the fourth direction intersecting the third direction, and the fourth direction being parallel to or intersecting the first direction.

[0011] Furthermore, any two of the second electrodes are electrically isolated.

[0012] Furthermore, the plurality of second electrodes are arranged in parallel.

[0013] Furthermore, in the fourth direction, the distribution density of the second electrode is above 5 electrodes / cm.

[0014] Furthermore, the radial dimension of the first conductive contact and / or the second conductive contact is not greater than 300 μm, or the area of ​​the first conductive contact and / or the second conductive contact is not greater than 300 μm. 2 μm 2 .

[0015] Furthermore, the orthographic projections formed by any first conductive contact and any second conductive contact along the selected direction do not overlap.

[0016] Furthermore, the first electrode also includes a first pad and a first signal transmission line, the first pad being electrically connected in series with a first conductive contact, and the first signal transmission line being electrically connected to the first pad.

[0017] Furthermore, the first signal transmission line and the first pad are bonded and electrically connected by thermal pressing with a conductive adhesive film; Furthermore, the second electrode also includes a second pad and a second signal transmission line, the second pad being electrically connected in series with the second conductive contact, and the second signal transmission line being electrically connected to the second pad.

[0018] Furthermore, the second signal transmission line and the second pad are thermo-pressed together and electrically connected via conductive adhesive film.

[0019] Furthermore, the first protective layer is provided with a plurality of first windows, and the second protective layer is provided with a plurality of second windows. The plurality of first windows correspond to a portion of the second windows, and the other portion of the second windows correspond to the second conductive contacts. The portion of the first electrode layer, excluding the first conductive contact, is covered by the first protective layer. Each first conductive contact is exposed through a first window and a second window and is electrically connected to the temperature-sensitive sensing layer. The portion of the second electrode layer, excluding the second conductive contact, is covered by the second protective layer. Each second conductive contact is exposed through a second window and is electrically connected to the temperature-sensitive sensing layer.

[0020] Furthermore, both the first protective layer and the second protective layer are insulating, and the thickness of the first protective layer and / or the second protective layer is 5μm to 50μm.

[0021] Furthermore, the temperature-sensitive sensing layer is mainly formed of a flexible temperature-sensitive composite material with a network structure.

[0022] Furthermore, the flexible temperature-sensitive composite material includes nano-semiconductor materials, nano-metal materials, and polymers, with the nano-semiconductor materials and nano-metal materials filling the polymer.

[0023] Furthermore, the nano-metal material supports the surface of the nano-semiconductor material, and the nano-semiconductor material and the nano-metal material together fill the polymer.

[0024] Furthermore, the nano-semiconductor material includes carbon nanotubes with a network structure.

[0025] Furthermore, the nanomaterial includes platinum metal nanoparticles.

[0026] Furthermore, the polymer comprises polydimethylsiloxane.

[0027] Furthermore, the thickness of the temperature-sensitive sensing layer is 5μm~100μm.

[0028] Furthermore, the thickness of the thermally conductive layer is 5μm to 30μm.

[0029] In a more specific implementation, the distributed flexible temperature sensor array further includes a flexible substrate, and the first electrode layer is disposed on the flexible substrate. The flexible substrate is made of a composite material formed from any one or more of the following materials: polyetherimide, polyimide, polyethylene terephthalate, polytetrafluoroethylene, and polymethyl methacrylate.

[0030] Another aspect of the present invention provides a method for fabricating the aforementioned distributed flexible temperature sensor array, comprising: A first electrode layer is prepared, the first electrode layer including at least one first electrode, the first electrode including a plurality of first conductive contacts, the plurality of first conductive contacts being spaced apart along a first direction and connected in series sequentially; A first protective layer is formed on the first electrode layer; A second electrode layer is formed on the first protective layer. The second electrode includes a plurality of second conductive contacts. The plurality of second conductive contacts are spaced apart along a third direction and connected in series. The first direction intersects with the third direction. A second protective layer is formed on the second electrode layer; A temperature-sensitive sensing layer is formed on the second protective layer, and the temperature-sensitive sensing layer is electrically connected to the first conductive contact and the second conductive contact. The temperature-sensitive sensing layer, the first conductive contact, and the second conductive contact form a sensing unit. A thermally conductive layer is formed on the temperature-sensitive sensing layer.

[0031] Furthermore, the method for fabricating the distributed flexible temperature sensor array specifically includes: A first protective layer is formed on the first electrode layer, and the first protective layer covers the part of the first electrode layer except for the first conductive contact. The area of ​​the first protective layer corresponding to the first conductive contact forms a hollow first window, and the first conductive contact is exposed from the first window. Furthermore, a second protective layer is formed on the second electrode layer, and the second protective layer covers the portion of the first electrode layer excluding the first conductive contact and the portion of the second electrode layer excluding the second conductive contact. The area of ​​the second protective layer corresponding to the first conductive contact and the area corresponding to the second conductive contact form a hollowed-out second window. The first conductive contact and the second conductive contact are also exposed through the second window and electrically connected to the temperature-sensitive sensing layer.

[0032] Furthermore, the first electrode also includes a first pad and a first signal transmission line, wherein the first pad is electrically connected in series with the first conductive contact, and the first signal transmission line is electrically connected to the first pad.

[0033] Furthermore, the preparation method specifically includes: setting a conductive adhesive film between the first signal transmission line and the first pad, heating the temperature of the conductive adhesive film to 60 ℃~100 ℃, and simultaneously applying pressure to the first signal transmission line and the first pad for 3 seconds~10 seconds, so that the first signal transmission line and the first pad are fixedly bonded and electrically connected. Furthermore, the second electrode also includes a second pad and a second signal transmission line, the second pad being electrically connected in series with the second conductive contact, and the second signal transmission line being electrically connected to the second pad.

[0034] Furthermore, the preparation method specifically includes: setting a conductive adhesive film between the second signal transmission line and the second pad, heating the temperature of the conductive adhesive film to 60 ℃~100 ℃, and simultaneously applying pressure to the second signal transmission line and the second pad for 3 seconds~10 seconds, so that the second signal transmission line and the second pad are fixedly bonded and electrically connected.

[0035] Furthermore, the method for preparing the temperature-sensitive sensing layer includes: Nanomaterials are loaded onto the surface of nanomaterials to obtain nanomaterials-loaded semiconductor thermosensitive composite materials. The nanomaterials-loaded semiconductor thermosensitive composite materials are then filled into a polymer to obtain a flexible thermosensitive composite material, which forms the thermosensitive sensing layer.

[0036] Furthermore, the method for preparing the temperature-sensitive sensing layer includes: loading sodium dodecyl sulfate onto the surface of the nano-semiconductor material to make the surface of the nano-semiconductor material exhibit negative charge; In a liquid-phase mixing system, the nano-semiconductor material is mixed with a nano-metal material salt, and the nano-metal ions in the nano-metal material salt are reduced to form a nano-metal material. The nano-metal material is adsorbed on the surface of the nano-semiconductor material, thereby obtaining a nano-semiconductor temperature-sensitive composite material loaded with nano-metal material.

[0037] Compared with the prior art, the advantages of the present invention include: 1) This invention utilizes a flexible temperature-sensitive composite material with a network structure prepared by in-situ synthesis technology as a temperature-sensitive sensing layer. The resulting flexible temperature-sensitive sensor has high measurement accuracy, high stability, and good reliability.

[0038] 2) This invention adopts a miniaturized array structure, which can realize distributed detection of temperature over a large area and at multiple points. The detection results are more accurate and reliable. Compared with single-point temperature sensors, which must be replaced in time if damaged, this invention has greater advantages in terms of safety, reliability and subsequent maintainability of temperature monitoring.

[0039] 3) The distributed flexible temperature sensor array provided by this invention is flexible and thin, which can not only be applied to the application scenarios of currently commercial rigid temperature sensors, but also be widely used in temperature measurement on irregular surfaces and narrow spaces, greatly expanding the application scenarios of flexible temperature sensors and making them more suitable for diversified application needs. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the longitudinal cross-sectional structure of a distributed flexible temperature sensor array provided in a typical embodiment of the present invention; Figure 2 This is a schematic diagram of a distributed flexible temperature sensor array provided in a typical embodiment of the present invention; Figure 3 This is a partial structural schematic diagram of a distributed flexible temperature sensor array provided in a typical embodiment of the present invention; Figure 4 This is a SEM image of the MWCNTs / Pt composite material obtained by this invention; Figure 5 This is a partial structural schematic diagram of a distributed flexible temperature sensor array provided in a typical embodiment of the present invention; Figure 6 This is a real-time response curve of a distributed flexible temperature sensor array to changes in ambient temperature, provided in a typical embodiment of the present invention. Figure 7 This is a curve showing the relationship between the resistance change rate and temperature of a distributed flexible temperature sensor array provided in a typical embodiment of the present invention. Detailed Implementation

[0041] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate the technical solution, its implementation process, and principles in conjunction with the accompanying drawings and specific embodiments. Unless otherwise specified, the materials used in the embodiments of this invention for preparing the distributed flexible temperature sensor array are all commercially available, and the processes used to form each structural layer in the distributed flexible temperature sensor array are also known to those skilled in the art.

[0042] Please see Figure 1 A distributed flexible temperature sensor array includes a flexible substrate 110, a first electrode layer 120, a first protective layer 130, a second electrode layer 140, a second protective layer 150, a temperature-sensitive sensing layer 160, and a thermally conductive layer 170, which are stacked sequentially along a selected direction. The temperature-sensitive sensing layer 160 is electrically connected to the first electrode layer 120 and the second electrode layer 140 to form a temperature-sensitive structure. The selected direction is the longitudinal direction of the device.

[0043] Specifically, the flexible substrate 110 and the top flexible substrate 120 are made of composite materials formed by any one or more of polyimide (PI), polyetherimide (PEI), and polytetrafluoroethylene (FEP).

[0044] To effectively reduce signal crosstalk between array units and ensure the high degree of independence between each array unit of the flexible temperature sensor array, this invention adopts a row-column crossover method to design a miniaturized array unit for flexible electrodes.

[0045] Please refer to the following for details. Figure 1 , Figure 2 and Figure 3 The first electrode layer 120 includes a plurality of first electrodes 1210 spaced apart and parallel to each other along a second direction. The arrangement density of the first electrodes 1210 in the second direction is not less than 10 electrodes / cm to form a high-density row / column electrode. The second electrode layer 140 includes a plurality of second electrodes 1410 spaced apart and parallel to each other along a fourth direction. The distribution density of the second electrodes 1410 in the fourth direction is not less than 10 electrodes / cm to form a high-density column / row electrode. Specifically, the fourth direction intersects the second direction, preferably perpendicularly. It can be understood that the orthographic projections formed by the first electrodes 1210 and the second electrodes 1410 along the selected direction intersect, preferably perpendicularly, that is, forming a flexible electrode miniaturized array unit with row and column intersection.

[0046] Specifically, each first electrode 1210 includes several first conductive contacts 1211, a first pad 1212, and a first signal transmission line 1213. Each first electrode 1210 ultimately leads out a first signal transmission line 1213 through the first pad 1212. That is, the first signal transmission line 1213 is electrically connected to the first pad 1212 and is electrically connected to the first conductive contacts 1211 through the first pad 1212.

[0047] Specifically, a plurality of first conductive contacts 1211 are arranged sequentially at intervals and connected in series along a first direction. The shape of each first conductive contact 1211 is not limited, such as square, rhombus, circle, polygon, etc. The radial dimension (e.g., side length or diameter) of each first conductive contact 1211 is not greater than 300μm. The first direction intersects the second direction, preferably perpendicularly. It can be understood that when the first direction and the second direction intersect perpendicularly, the first direction is parallel to the fourth direction.

[0048] Specifically, a first protective layer 130 is deposited on the first electrode layer 120 (for example, the first protective layer 130 can be deposited on the surface of the first electrode layer 120 by coating, printing, or other processes). The first protective layer 130 covers the portion except for the plurality of first conductive contacts 1211. That is, the first protective layer 130 is provided with a plurality of first windows 1310, each first window 1310 corresponding to a first conductive contact 1211, each first conductive contact 1211 protruding from a first window 1310 and electrically connected to the temperature-sensitive sensing layer 160. More specifically, the material of the first protective layer 130 is the same as that of the flexible substrate 110. In order to balance good insulation performance and flexibility, the thickness of the first protective layer 130 is preferably 5μm to 50μm.

[0049] Specifically, each second electrode 1410 of the second electrode layer 140 includes several second conductive contacts 1411, a second pad 1412, and a second signal transmission line 1413. Each second electrode 1410 is ultimately led out through the second pad 1412 to form a second signal transmission line 1413. That is, the second signal transmission line 1413 is electrically connected to the second pad 1412 and is electrically connected to the second conductive contacts 1411 through the second pad 1412.

[0050] Specifically, a plurality of second conductive contacts 1411 are arranged sequentially at intervals and connected in series along a third direction. The shape of each second conductive contact 1411 is not limited, for example, it can be square, rhomboid, circular, polygonal, etc. The radial dimension (e.g., side length or diameter) of each second conductive contact 1411 is not greater than 300μm. The third direction intersects the fourth direction, preferably perpendicularly. It can be understood that when the third direction and the fourth direction intersect perpendicularly, the third direction is parallel to the second direction.

[0051] Specifically, a second protective layer 150 is applied to the surface of the second electrode layer 140. The second protective layer 150 covers the area excluding the first conductive contacts 1211 of the first electrode layer 120 and the second conductive contacts 1411 of the second electrode layer 140. That is, the second protective layer 150 has multiple second windows 1510, each corresponding to a first conductive contact 1211 or a second conductive contact 1411. Each first conductive contact 1211 protrudes from a first window 1310 or a second window 1510 and is electrically connected to the temperature-sensitive sensing layer 160. Each second conductive contact 1411 protrudes from a second window 1510 and is electrically connected to the temperature-sensitive sensing layer 160. More specifically, the material of the second protective layer 150 is the same as that of the flexible substrate 110. To balance good insulation performance and flexibility, the thickness of the second protective layer 150 is preferably 5μm to 50μm.

[0052] Specifically, the temperature-sensitive sensing layer 160 is preferably made of composite functional materials with porous microstructures, such as carbon nanomaterials, two-dimensional materials, and gel materials. The thickness of the temperature-sensitive sensing layer 160 is 5μm to 25μm. The temperature-sensitive sensing layer 160 is electrically connected to the first conductive contact 1211 and the second conductive contact 1411. The temperature-sensitive sensing layer 160 and the first conductive contact 1211 and the second conductive contact 1411 are connected to form a sensing unit.

[0053] Specifically, the temperature-sensitive sensing layer 160 is formed of a flexible temperature-sensitive composite material made of nano-semiconductor materials, nano-metal materials, and polymers, and the thickness of the temperature-sensitive sensing layer 160 is 5μm to 100μm.

[0054] More specifically, the nano-semiconductor material can be a network-structured carbon nanotube (MWCNTs), the nano-metal material can be platinum (Pt) metal nanoparticles, and the polymer can be polydimethylsiloxane (PDMS). This invention selects network-structured carbon nanotubes (MWCNTs) loaded with platinum (Pt) metal nanoparticles and filled with a polydimethylsiloxane (PDMS) polymer to obtain a flexible temperature-sensitive composite material. Carbon nanotubes are a highly stable material with a unique network structure and good thermal and electrical conductivity. Loading platinum metal particles helps improve the measurement accuracy and stability of the flexible temperature sensor, and further allows for the control of the material's electrical and thermal conductivity. Compared to other polymer materials, PDMS is an organic polymer with a high coefficient of thermal expansion (TCE) and exhibits good ductility and stability within the temperature range of -55℃ to 150℃. In the flexible temperature-sensitive composite material, through the synergistic effect of multiple materials, the carbon nanotube network structure supported by platinum metal nanoparticles makes full use of the high axial strength, toughness and elastic modulus of carbon nanotubes, ensuring the mechanical stability and flexibility of the prepared flexible sensitive film; the composite of PDMS ensures that a stable network is formed between the film layers, so that the flexible temperature-sensitive composite material has better response stability and repeatability.

[0055] Specifically, the thermally conductive layer 170 is disposed on the surface of the temperature-sensitive sensing layer 160, and can be formed by processes such as coating, printing, or attachment. The material of the thermally conductive layer 170 is preferably a liquid polymer material / thermal conductive silicone / thermal conductive gel with high thermal conductivity, excellent adhesion, and resistance to high and low temperatures. The thickness of the thermally conductive layer 170 is 5μm to 30μm. Because this thermally conductive layer material has a high thermal conductivity, it can quickly transfer the external temperature to the temperature-sensitive sensing layer, ensuring the rapid and sensitive response of the temperature sensor. At the same time, the thermally conductive layer material itself has good insulation and environmental stability, which provides good protection for the flexible temperature sensor.

[0056] To achieve miniaturized array structures, this invention develops a micro / nano fabrication method compatible with "bottom-up" MEMS processes, realizing effective compatibility and high integration between flexible sensing materials and traditional MEMS processes. The method for fabricating a distributed flexible temperature-sensitive sensor array on a flexible substrate using MEMS processes includes the following steps: (1) Preparation of flexible substrate A polyimide solution (viscosity 5000~12000 cps) is uniformly coated (600 rpm @ 6s + 1000 rpm @ 5s) onto a rigid substrate (such as a glass substrate or a silicon substrate), and then cured at 80℃~200℃ for 0.5 h~2.5 h to form a polyimide film with a thickness of 10μm~50μm. The cured polyimide film is then peeled off from the rigid substrate to obtain a flexible substrate 110.

[0057] (2) Preparation of the first electrode layer First electrodes 1210 spaced apart and parallel along a second direction are prepared on the surface of a flexible substrate 110 using MEMS processes (including spin coating, baking, exposure, and development steps). The distribution density of the first electrodes 1210 in the second direction is not less than 5 electrodes / cm. Specifically, a Cr film with a thickness of 5μm to 20μm (preferably 10μm) and an Au film with a thickness of 50μm to 150μm (preferably 100μm) can be deposited sequentially on the surface of the flexible substrate 110 to form a plurality of square first conductive contacts 1211 arranged sequentially along the first direction. The plurality of first conductive contacts 1211 are connected in series, and the side length of the first conductive contacts 1211 does not exceed 300μm.

[0058] (3) Preparation of the first protective layer A polyimide solution is uniformly coated (preferably by coating, printing, or other processes) (600 rmp@6s + 800 rmp@5s) on the surfaces of the first electrode layer 120 and the flexible substrate 110, covering the area excluding the first conductive contacts 1211 of the first electrode layer 120. The solution is then cured (curing temperature 80℃~200℃, curing time 0.5 h~2.5 h) to form a first protective layer 130 with a thickness of 5 μm to 30 μm. It should be noted that alternatively, an electrode layer can be formed on the entire surface of the first electrode layer 120 and the flexible substrate 110 firstly, and then exposed windows, i.e., the aforementioned first windows, can be formed in the areas corresponding to the first conductive contacts 1211.

[0059] (4) Preparation of the second electrode layer Multiple second electrodes 1410 spaced apart and parallel along the fourth direction are prepared on the surface of the first protective layer 130 using MEMS processes (including spin coating, baking, exposure, development, etc.). The distribution density of the second electrodes 1410 in the fourth direction is not less than 5 electrodes / cm. Specifically, a Cr film with a thickness of 5μm to 20μm (preferably 10μm) and an Au film with a thickness of 50μm to 150μm (preferably 100μm) can be deposited sequentially on the surface of the first protective layer 130 to form multiple square second conductive contacts 1411 arranged sequentially along the third direction. The multiple second conductive contacts 1411 are connected in series. The side length of the second conductive contacts 1411 does not exceed 300μm. The second conductive contacts 1411 and the first conductive contacts 1211 do not overlap in the orthographic projection area formed along the selected direction.

[0060] (5) Prepare the second protective layer A layer of polyimide solution is uniformly coated (preferably by coating, printing, or other processes) (600 rpm @ 6 s + 800 rpm @ 5 s) on the surface of the second electrode layer 140. The polyimide solution covers the area excluding the first conductive contacts 1211 of the first electrode layer 120 and the second conductive contacts 1411 of the second electrode layer 140, and then cured (curing temperature 80℃~200℃, curing time 0.5 h~2.5 h) to form a second protective layer 150 with a thickness of 5 μm~30 μm. It should be noted that a polyimide film can also be formed on the entire surface of the second electrode layer 140 and the first protective layer 130 firstly, and then exposed windows, i.e., the aforementioned second windows, can be formed in the areas corresponding to the first conductive contacts 1211 and the second conductive contacts 1411.

[0061] 6) Fabrication of the temperature-sensitive sensing layer This invention employs a two-step in-situ synthesis technique to prepare flexible nanocomposite temperature-sensitive materials with a network structure: The first step involves adsorbing sodium dodecyl sulfate (SDS) onto the surface of multi-walled carbon nanotubes (MWCNTs) with a network structure through non-covalent bonds and electrostatic interactions, making the surface negatively charged to facilitate the adsorption of platinum nanoparticles. Then, by gradually adjusting the pH value of the reaction system in situ, platinum nanoparticles are homogeneously deposited on the surface of the MWCNTs. The second step involves adding a weak reducing agent at a certain temperature to reduce the positive-valent platinum metal in the reaction system in situ, thereby loading platinum metal nanoparticles onto the surface of multi-walled carbon nanotubes to obtain platinum metal nanoparticle-loaded multi-walled carbon nanotubes.

[0062] The specific steps are as follows: (a) Measure out 36%–38% hydrochloric acid and 30% hydrogen peroxide by mass and mix them in a volume ratio of 3:1. Add the annealed multi-walled carbon nanotubes to the mixture and reflux at 60°C for 4 hours. After filtration, washing and drying, the mixture is ready for use.

[0063] (b) The purified multi-walled carbon nanotubes and sodium dodecyl sulfate (SDS) were mixed in a ratio of 1:2 to 1:6 (mass to volume ratio) and sonicated for 3 hours. The sonicated multi-walled carbon nanotubes / sodium dodecyl sulfate / water solution was centrifuged and 60% (volume fraction) of the supernatant was collected.

[0064] (c) Add H2PtCl6•6H2O (0.05 mol / L) and urea at a mass ratio of 1:1.4 to 1:4.4 to the supernatant, and heat the mixture at 60℃ to 90℃ for 1 to 3.5 hours. Then add a weak reducing agent (such as ethylene glycol (EG)) and stir for 3 hours. Subsequently, raise the temperature to 100℃ to 120℃ and stir for 8 to 14 hours to obtain a black precipitate of MWCNTs / Pt composite material. Centrifuge and dry the precipitate. The SEM image of the obtained MWCNTs / Pt composite material is shown below. Figure 4 As shown.

[0065] (d) The prepared MWCNTs / Pt composite material was dispersed in cyclohexane, and after adding PDMS stock solution, it was magnetically stirred for 2 to 4 hours, and then ultrasonically dispersed for 1 to 3 hours. After adding the appropriate proportion (10:1) of special silane crosslinking agent (PDMS184 special curing agent), the MWCNTs / Pt / PDMS dispersion was obtained for use.

[0066] (e) A MWCNTs / Pt / PDMS thin film with a thickness of 5μm to 100μm is formed on the surface of the second protective layer by spraying or printing as a temperature-sensitive sensing layer, and the MWCNTs / Pt / PDMS thin film is electrically connected to the first conductive contact and the second conductive contact.

[0067] 7) Fabrication of the thermally conductive layer A liquid polymer material with a thickness of 5μm to 30μm, which has high thermal conductivity, excellent adhesion, and resistance to high and low temperatures, is formed on the surface of the electrode layer and the temperature-sensitive sensing layer through processes such as coating, printing, and bonding. This liquid polymer material includes thermally conductive silicone / thermally conductive gel, etc. For thermally conductive silicone / thermally conductive gel, a film can be formed by a scraping / bonding process.

[0068] 8) Fabrication of a distributed flexible temperature sensor array A distributed flexible temperature sensor array is obtained by curing the thermally conductive layer prepared by scraping / spraying / printing processes into a film, or by cutting the thermally conductive film prepared by bonding processes into shape.

[0069] 9) Connecting the electrode pads and signal transmission lines of the distributed flexible temperature sensor array. To address the compatibility issues between the signal transmission of a distributed flexible temperature sensor array and the backend signal acquisition system, and to achieve highly stable signal transmission, this invention provides a high-density array electrode serial port stable lead technology. This technology involves using a conductive adhesive film (preferably an epoxy resin-based conductive film) to thermally press the pads of the row and column electrodes (i.e., the aforementioned first and second electrodes) and the signal transmission lines at high temperature (60°C~100°C) for a short period (3-10 seconds) to achieve conductive connection between the row and column electrode pads and the signal transmission lines. Simultaneously, it avoids short circuits between adjacent electrodes with fine spacing. Figure 5 As shown.

[0070] After stably connecting the distributed flexible temperature sensor array provided by this invention to the back-end signal acquisition system, the flexible temperature sensor is placed in a temperature test chamber. The starting and ending temperatures of the temperature chamber are set to 20°C and 70°C, respectively, with a heating rate of 5°C per minute. The changes in the output electrical signal of the flexible temperature sensor are recorded, and the test results are obtained. Figure 6 and Figure 7 As shown, by Figure 6 and Figure 7 It can be seen that as the ambient temperature increases from 20°C to 70°C at a rate of 5°C / minute, the output resistance of the flexible temperature sensor increases step by step, and it shows good synchronization with the change in ambient temperature, indicating that the flexible temperature sensor provided by the present invention has a linear response to temperature.

[0071] This invention utilizes a flexible temperature-sensitive composite material with a network structure prepared by in-situ synthesis technology as a temperature-sensitive sensing layer, thereby obtaining a flexible temperature-sensitive sensor with high measurement accuracy, high stability, and good reliability.

[0072] This invention employs a miniaturized array structure, enabling distributed temperature detection over a large area and at multiple points. The detection results are more accurate and reliable. Compared to single-point temperature sensors, which must be replaced promptly if damaged, this invention offers greater advantages in terms of safety, reliability, and subsequent maintainability for temperature monitoring.

[0073] The distributed flexible temperature sensor array provided by this invention is flexible and thin, which can not only be applied to the application scenarios of currently commercial rigid temperature sensors, but also be widely used in temperature measurement on irregular surfaces and narrow spaces, greatly expanding the application scenarios of flexible temperature sensors and making them more suitable for diversified application needs.

[0074] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A distributed flexible temperature sensor array, characterized in that, include: A first electrode layer, a first protective layer, a second electrode layer, a second protective layer, a temperature-sensitive sensing layer, and a heat-conducting layer are sequentially stacked along a selected direction. The first electrode layer includes at least one first electrode, and the first electrode includes a plurality of first conductive contacts. The plurality of first conductive contacts are spaced apart along a first direction and connected in series. The second electrode layer includes a second electrode, and the second electrode includes a plurality of second conductive contacts. The plurality of second conductive contacts are spaced apart along a third direction and connected in series. The first conductive contacts and the second conductive contacts are both electrically connected to the temperature-sensitive sensing layer. The temperature-sensitive sensing layer, a first conductive contact, and a second conductive contact form a sensing unit, wherein the first direction intersects the third direction. Furthermore, the first protective layer is provided with a plurality of first windows, and the second protective layer is provided with a plurality of second windows. The plurality of first windows correspond to a portion of the second windows, and the other portion of the second windows correspond to the second conductive contacts. The portion of the first electrode layer other than the first conductive contacts is covered by the first protective layer. Each first conductive contact is exposed from a first window and a second window and is electrically connected to the temperature-sensitive sensing layer. The portion of the second electrode layer other than the second conductive contacts is covered by the second protective layer. Each second conductive contact is exposed from a second window and is electrically connected to the temperature-sensitive sensing layer. Both the first protective layer and the second protective layer are insulated.

2. The distributed flexible temperature sensor array according to claim 1, characterized in that: The first electrode layer includes a plurality of first electrodes, which are arranged sequentially at intervals along a second direction. The second direction intersects the first direction and is parallel to or intersects the third direction.

3. The distributed flexible temperature sensor array according to claim 2, characterized in that: Electrical isolation between any two of the first electrodes.

4. The distributed flexible temperature sensor array according to claim 2, characterized in that: The plurality of first electrodes are arranged in parallel.

5. The distributed flexible temperature sensor array according to claim 2, characterized in that: In the second direction, the distribution density of the first electrode is 5 or more per cm.

6. The distributed flexible temperature sensor array according to claim 2, characterized in that: The second electrode layer includes a plurality of second electrodes, which are arranged sequentially at intervals along a fourth direction, which intersects the third direction and is parallel to or intersects the first direction.

7. The distributed flexible temperature sensor array according to claim 6, characterized in that: Electrical isolation between any two of the second electrodes.

8. The distributed flexible temperature sensor array according to claim 6, characterized in that: Multiple second electrodes are arranged in parallel.

9. The distributed flexible temperature sensor array according to claim 6, characterized in that: In the fourth direction, the distribution density of the second electrode is more than 5 per cm.

10. The distributed flexible temperature sensor array according to claim 1, characterized in that: The radial dimension of the first conductive contact and / or the second conductive contact is not greater than 300 μm, or the area of ​​the first conductive contact and / or the second conductive contact is not greater than 300 μm. 2 μm 2 .

11. The distributed flexible temperature sensor array according to claim 1, characterized in that: The orthographic projections formed by any first conductive contact and any second conductive contact along the selected direction do not overlap.

12. The distributed flexible temperature sensor array according to claim 1 or 2, characterized in that: The first electrode further includes a first pad and a first signal transmission line. The first pad is electrically connected in series with a first conductive contact, and the first signal transmission line is electrically connected to the first pad.

13. The distributed flexible temperature sensor array according to claim 12, characterized in that: The first signal transmission line is thermo-pressed and electrically connected to the first pad through a conductive adhesive film.

14. The distributed flexible temperature sensor array according to claim 1 or 6, characterized in that: The second electrode also includes a second pad and a second signal transmission line. The second pad is electrically connected in series with the second conductive contact, and the second signal transmission line is electrically connected to the second pad.

15. The distributed flexible temperature sensor array according to claim 14, characterized in that: The second signal transmission line and the second pad are bonded and electrically connected by thermal pressing with a conductive adhesive film.

16. The distributed flexible temperature sensor array according to claim 1, characterized in that: The thickness of the first protective layer and / or the second protective layer is 5μm to 50μm.

17. The distributed flexible temperature sensor array according to claim 1, characterized in that: The temperature-sensitive sensing layer is formed of a flexible temperature-sensitive composite material with a network structure.

18. The distributed flexible temperature sensor array according to claim 17, characterized in that: The flexible temperature-sensitive composite material includes nano-semiconductor materials, nano-metal materials, and polymers, with the nano-semiconductor materials and nano-metal materials filling the polymer.

19. The distributed flexible temperature sensor array according to claim 18, characterized in that: The nano-metal material is loaded on the surface of the nano-semiconductor material, and the nano-semiconductor material and the nano-metal material form a whole that fills the polymer.

20. The distributed flexible temperature sensor array according to claim 18 or 19, characterized in that: The nano-semiconductor material includes carbon nanotubes with a network structure.

21. The distributed flexible temperature sensor array according to claim 18 or 19, characterized in that: The nanomaterials include platinum metal nanoparticles.

22. The distributed flexible temperature sensor array according to claim 18 or 19, characterized in that: The polymer includes polydimethylsiloxane.

23. The distributed flexible temperature sensor array according to claim 1, characterized in that: The thickness of the temperature-sensitive sensing layer is 5μm~100μm.

24. The distributed flexible temperature sensor array according to claim 1, characterized in that: The thickness of the thermally conductive layer is 5μm to 30μm.

25. The distributed flexible temperature sensor array according to claim 1, characterized in that, It also includes a flexible substrate, on which the first electrode layer is disposed. The flexible substrate is made of a composite material formed by any one or more of the following materials: polyetherimide, polyimide, polyethylene terephthalate, polytetrafluoroethylene, and polymethyl methacrylate.

26. A method for fabricating a distributed flexible temperature-sensitive sensor array as described in any one of claims 1-25, characterized in that... include: A first electrode layer is prepared, the first electrode layer including at least one first electrode, the first electrode including a plurality of first conductive contacts, the plurality of first conductive contacts being spaced apart along a first direction and connected in series sequentially; A first protective layer is formed on the first electrode layer, and the first protective layer covers the part of the first electrode layer except for the first conductive contact. The area of ​​the first protective layer corresponding to the first conductive contact forms a hollow first window, and the first conductive contact is exposed from the first window. A second electrode layer is formed on the first protective layer. The second electrode layer includes a second electrode. The second electrode includes a plurality of second conductive contacts. The plurality of second conductive contacts are spaced apart along a third direction and connected in series. The first direction intersects with the third direction. A second protective layer is formed on the second electrode layer, and the second protective layer covers the portion of the first electrode layer excluding the first conductive contact and the portion of the second electrode layer excluding the second conductive contact. The area of ​​the second protective layer corresponding to the first conductive contact and the area corresponding to the second conductive contact form a hollowed-out second window. A temperature-sensitive sensing layer is formed on the second protective layer, and the temperature-sensitive sensing layer is electrically connected to the first conductive contact and the second conductive contact. The temperature-sensitive sensing layer, the first conductive contact, and the second conductive contact form a sensing unit. A thermally conductive layer is formed on the temperature-sensitive sensing layer.

27. The method for fabricating a distributed flexible temperature-sensitive sensor array according to claim 26, characterized in that: The first electrode further includes a first pad and a first signal transmission line. The first pad is electrically connected in series with the first conductive contact, and the first signal transmission line is electrically connected to the first pad.

28. The method for fabricating a distributed flexible temperature-sensitive sensor array according to claim 27, characterized in that, The preparation method specifically includes: setting a conductive adhesive film between the first signal transmission line and the first pad, heating the temperature of the conductive adhesive film to 60 ℃~100 ℃, and simultaneously applying pressure to the first signal transmission line and the first pad for 3 seconds~10 seconds, so that the first signal transmission line and the first pad are fixedly bonded and electrically connected.

29. The method for fabricating a distributed flexible temperature-sensitive sensor array according to claim 26, characterized in that: The second electrode also includes a second pad and a second signal transmission line. The second pad is electrically connected in series with the second conductive contact, and the second signal transmission line is electrically connected to the second pad.

30. The method for fabricating a distributed flexible temperature-sensitive sensor array according to claim 29, characterized in that, The preparation method specifically includes: setting a conductive adhesive film between the second signal transmission line and the second pad, heating the temperature of the conductive adhesive film to 60 ℃~100 ℃, and simultaneously applying pressure to the second signal transmission line and the second pad for 3 seconds~10 seconds, so that the second signal transmission line and the second pad are fixedly bonded and electrically connected.

31. The method for fabricating a distributed flexible temperature-sensitive sensor array according to claim 26, characterized in that, The method for preparing the temperature-sensitive sensing layer includes: Nanomaterials are loaded onto the surface of nanomaterials to obtain nanomaterials-loaded semiconductor thermosensitive composite materials. The nanomaterials-loaded semiconductor thermosensitive composite materials are then filled into a polymer to obtain a flexible thermosensitive composite material, which forms the thermosensitive sensing layer.

32. The method for fabricating a distributed flexible temperature-sensitive sensor array according to claim 31, characterized in that, The method for preparing the temperature-sensitive sensing layer includes: loading sodium dodecyl sulfate onto the surface of the nano-semiconductor material to make the surface of the nano-semiconductor material exhibit negative charge; In a liquid-phase mixing system, the nano-semiconductor material is mixed with a nano-metal material salt, and the nano-metal ions in the nano-metal material salt are reduced to form a nano-metal material. The nano-metal material is adsorbed on the surface of the nano-semiconductor material, thereby obtaining a nano-semiconductor temperature-sensitive composite material loaded with nano-metal material.

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