Flexible sensor and preparation method thereof

Abstract

The invention discloses a flexible sensor and a preparation method thereof. The flexible sensor comprises a first circuit substrate, a second circuit substrate and a third circuit substrate. The first circuit substrate comprises a first base material layer, a plurality of first conductive circuits, a plurality of second conductive circuits, a first conduction body and a second conduction body, and the plurality of first conductive circuits are arranged on one side of the first base material layer at intervals; the multiple second conductive circuits are arranged on the side, away from the first conductive circuit, of the first base material layer at intervals, the first conduction bodies and the second conduction bodies are arranged at intervals, the first conduction bodies penetrate through the first base material layer and are electrically connected with the first conductive circuits and the second conductive circuits, and the second conduction bodies penetrate through the second base material layer and are electrically connected with the first conductive circuits and the second conductive circuits. The second conducting body penetrates through the first base material layer and is electrically connected with the first conducting circuits and the second conducting circuits, and the first conducting bodies and the second conducting bodies electrically connect the multiple first conducting circuits and the multiple second conducting circuits in series.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sensors, in particular to a flexible sensor and a preparation method thereof. BACKGROUND

[0002] The flexible sensor is combined by a flexible substrate and a conductor, and can convert special signals such as external stress or heat into electrical signals and transmit the signals to a computer for signal processing. The flexible sensor has good flexibility and ductility, and can be arranged arbitrarily according to measurement requirements, so it has good application prospects in medical electronics, environmental monitoring and wearable electronics.

[0003] In the prior art, most flexible sensors usually have single function and can only measure a single parameter, and the functional areas of a few flexible integrated sensors are prone to mutual interference, affecting the sensitivity and accuracy. Therefore, it is urgent to develop a flexible integrated sensor with good sensitivity and sensing accuracy. SUMMARY

[0004] Therefore, the present application provides a flexible sensor and a preparation method thereof which can solve the above problems.

[0005] The first aspect of the present application provides a flexible sensor, comprising a first circuit substrate, a second circuit substrate and a third circuit substrate. The first circuit substrate comprises a first substrate layer, a plurality of first conductive lines, a plurality of second conductive lines, a first conductive body and a second conductive body, the plurality of first conductive lines are arranged at intervals on one side of the first substrate layer, the plurality of second conductive lines are arranged at intervals on the side of the first substrate layer away from the first conductive lines, the first conductive body and the second conductive body are arranged at intervals, the first conductive body penetrates the first substrate layer and is electrically connected with the first conductive lines and the second conductive lines, the second conductive body penetrates the first substrate layer and is electrically connected with the first conductive lines and the second conductive lines, and the first conductive body and the second conductive body electrically connect the plurality of first conductive lines arranged at intervals and the plurality of second conductive lines arranged at intervals in series; the second circuit substrate is located on one side of the first circuit substrate, and the second circuit substrate is provided with a strain resistance layer; the third circuit substrate is located on the side of the first circuit substrate away from the second circuit substrate, and the third circuit substrate is provided with a humidity sensing layer.

[0006] In some embodiments, the flexible sensor further comprises a first dielectric layer and a second dielectric layer, the first dielectric layer is located between the strain resistance layer and the first substrate layer, and the second dielectric layer is located between the first substrate layer and the humidity sensing layer.

[0007] In some embodiments, the first conductive body protrudes from a surface of the first substrate layer facing away from the second conductive lines, and the second conductive body protrudes from a surface of the first substrate layer facing away from the first conductive lines.

[0008] In some embodiments, the material of the strain resistance layer comprises at least one of a conductive polymer, a conductive carbon material, and a metal.

[0009] In some embodiments, the material of the first conductive body is copper, and the material of the second conductive body is copper-nickel alloy.

[0010] In some embodiments, the material of the humidity sensing layer comprises titanium oxide nanoparticles and a conductive polymer.

[0011] In some embodiments, the material of the first dielectric layer and the second dielectric layer comprises at least one of polydimethylsiloxane, thermoplastic polyurethane elastomer, and pressure-sensitive adhesive.

[0012] The second aspect of the present application provides a method for manufacturing a flexible sensor, comprising the following steps:

[0013] A first circuit substrate is provided, which comprises a first substrate layer, a plurality of first conductive lines, a plurality of second conductive lines, a first conductive body, and a second conductive body. The plurality of first conductive lines are arranged on one side of the first substrate layer, the plurality of second conductive lines are arranged on the side of the first substrate layer facing away from the first conductive lines, the first conductive body and the second conductive body are arranged in a spaced manner, the first conductive body penetrates the first substrate layer and is electrically connected to the first conductive lines and the second conductive lines, the second conductive body penetrates the first substrate layer and is electrically connected to the first conductive lines and the second conductive lines, and the first conductive body and the second conductive body electrically connect the plurality of spaced first conductive lines and the plurality of spaced second conductive lines in series.

[0014] A second circuit substrate is provided, which is located on one side of the first circuit substrate, and is provided with a strain resistance layer.

[0015] A third circuit substrate is provided, which is located on the side of the first circuit substrate facing away from the second circuit substrate, and is provided with a humidity sensing layer.

[0016] The first circuit substrate, the second circuit substrate, and the third circuit substrate are stacked in sequence.

[0017] In some embodiments, the material of the first conductive body is copper, and the material of the second conductive body is copper-nickel alloy.

[0018] In some embodiments, the material of the humidity sensing layer comprises titanium oxide nanoparticles and a conductive polymer.

[0019] The flexible sensor provided by the present application integrates three sensing function layers of pressure, temperature and humidity. The first circuit substrate is a temperature sensing layer, the second circuit substrate is a pressure sensing layer, and the third circuit substrate is a humidity sensing layer. The signals of each function layer are independently monitored and output, and do not affect each other. At the same time, they can monitor and correct each other's data. For example, the pressure sensing layer is easily affected by temperature changes, and its sensitivity curve is affected. By measuring the temperature change through the temperature sensing layer, the detection of external force can be effectively assisted and corrected, thereby reducing the influence of temperature on the pressure sensing layer, and improving the sensitivity and accuracy of the flexible sensor. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A cross-sectional schematic view of the first substrate provided by an embodiment of the present application is shown.

[0021] Figure 2 A cross-sectional schematic view of the first substrate provided by an embodiment of the present application is shown. Figure 1 A cross-sectional schematic view of the first substrate provided by an embodiment of the present application is shown.

[0022] Figure 3 A cross-sectional schematic view of the first substrate provided by an embodiment of the present application is shown. Figure 2 A cross-sectional schematic view of the first substrate provided by an embodiment of the present application is shown.

[0023] Figure 4 A cross-sectional schematic view of the first substrate provided by an embodiment of the present application is shown. Figure 3 A cross-sectional schematic view of the first substrate provided by an embodiment of the present application is shown.

[0024] Figure 5 A cross-sectional schematic view of the first substrate provided by an embodiment of the present application is shown. Figure 4 A cross-sectional schematic view of the first substrate provided by an embodiment of the present application is shown.

[0025] Figure 6 A cross-sectional schematic view of the first substrate provided by an embodiment of the present application is shown. Figure 5 A cross-sectional schematic view of the first substrate provided by an embodiment of the present application is shown.

[0026] Figure 7 A cross-sectional schematic view of the first substrate provided by an embodiment of the present application is shown. Figure 6 A cross-sectional schematic view of the first substrate provided by an embodiment of the present application is shown.

[0027] Figure 8 A cross-sectional schematic view of the second substrate provided by an embodiment of the present application is shown.

[0028] Figure 9 A cross-sectional schematic view of the second substrate provided by an embodiment of the present application is shown.

[0029] Figure 10 A cross-sectional schematic view of the second substrate provided by an embodiment of the present application is shown. Figure 9A cross-sectional view of a structure provided with a strain resistance layer.

[0030] Figure 11 To provide a third substrate for Figure 10 A cross-sectional view of a structure provided with a third dielectric base layer and a fourth slot.

[0031] Figure 12 A cross-sectional view of a third substrate provided for an embodiment of the present application.

[0032] Figure 13 To provide a third substrate for Figure 12 A cross-sectional view of a third substrate provided with a fifth slot.

[0033] Figure 14 To provide a third substrate for Figure 13 A cross-sectional view of a structure provided with a humidity sensing layer.

[0034] Figure 15 To provide a third substrate for Figure 14 A cross-sectional view of a structure provided with a fourth dielectric base layer.

[0035] Figure 16 A cross-sectional view of a flexible sensor provided for an embodiment of the present application.

[0036] Explanation of main element symbols

[0037]

[0038] DETAILED DESCRIPTION

[0039] In order to more clearly understand the above objectives, features and advantages of the embodiments of the present application, a more precise description will be provided below with reference to the accompanying drawings and specific embodiments. It should be noted that the features in the embodiments of the present application can be combined with each other as long as they do not conflict.

[0040] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the embodiments of the present application. The described embodiments are only some of the embodiments of the present application, and are not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the embodiments of the present application.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of the present application belong. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments and are not intended to limit the embodiments of the present application.

[0042] Please refer toFigures 1 to 16 In an embodiment of the present application, a method for manufacturing a flexible sensor 100 is provided, comprising the following steps:

[0043] Step S1 : Please refer to Figure 1 A first substrate 10 is provided, which comprises a first base material layer 11, a first conductive layer 12 and a second conductive layer 13. The first conductive layer 12 and the second conductive layer 13 are respectively arranged on opposite sides of the first base material layer 11.

[0044] In the present embodiment, the first substrate 10 is a double-sided copper-clad plate, and the first conductive layer 12 and the second conductive layer 13 are both copper foils. The material of the first base material layer 11 includes, but is not limited to, transparent flexible materials such as polyimide (PI) and polyethylene naphthalate two formic acid glycol ester (PEN).

[0045] Step S2: Please refer to Figure 2 A plurality of first grooves 121 and a plurality of second grooves 131 are respectively arranged on the first substrate 10. The plurality of first grooves 121 are arranged at intervals, and each first groove 121 penetrates the first conductive layer 12 and the first base material layer 11, so that part of the second conductive layer 13 is exposed at the bottom of the first groove 121. Similarly, the plurality of second grooves 131 are arranged at intervals, and each second groove 131 penetrates the second conductive layer 13 and the first base material layer 11, so that part of the first conductive layer 12 is exposed at the bottom of the second groove 131.

[0046] In the present embodiment, the plurality of first grooves 121 and the plurality of second grooves 131 are formed by laser ablation. It can be understood that in other embodiments of the present application, the plurality of first grooves 121 and the plurality of second grooves 131 can be formed by other methods, such as mechanical drilling, machine punching, chemical etching, etc.

[0047] Step S3: Please refer to Figure 3A first conductive body 14 is disposed within the first groove 121, connecting the first conductive layer 12 and the second conductive layer 13. In this embodiment, the first conductive body 14 fills the first groove 121, and the surface of the first conductive body 14 facing away from the first substrate layer 11 is flush with the surface of the first conductive layer 12 facing away from the first substrate layer 11. The first conductive body 14 electrically connects the first conductive layer 12 and the second conductive layer 13. The first conductive body 14 is made of copper. Understandably, in other embodiments of this application, the first conductive body 14 may be made of other conductive metals such as aluminum or silver. The first conductive body 14 is formed by electroplating. In other embodiments of this application, the first conductive body 14 may also be formed within the first groove 121 by chemical deposition or other methods.

[0048] Step S4: Please refer to Figure 4 A second conductive body 15 is formed within a plurality of second grooves 131, and the second conductive body 15 is electrically connected to the first conductive layer 12 and the second conductive layer 13. In this embodiment, the second conductive body 15 fills the second grooves 131 and is electrically connected to the first conductive layer 12 and the second conductive layer 13. The material of the second conductive body 15 is a copper-nickel alloy. It is understood that in other embodiments of this application, the material of the second conductive body 15 may be other materials such as bismuth metal that can form a potential difference with the material of the first conductive body 14.

[0049] Step S5: Please refer to Figure 5The first conductive layer 12 is etched to form a plurality of first conductive lines 16, and the second conductive layer 13 is etched to form a plurality of second conductive lines 17. A first conductive body 14 protrudes from the surface of the first substrate layer 11 away from the surface of the second conductive lines 17, and a second conductive body 15 protrudes from the surface of the first substrate layer 11 away from the surface of the first conductive lines 16. The plurality of first conductive lines 16 are spaced apart on one side of the first substrate layer 11, and the plurality of second conductive lines 17 are spaced apart on the other side of the first substrate layer 11. In the thickness direction A of the first substrate layer 11, the bottom of the first conductive body 14 is connected to the second conductive line 17, and the top of the first conductive body 14 is connected to the first conductive line 16. The bottom of the second conductive body 15 is connected to the second conductive line 17, and the top of the second conductive body 15 is connected to the first conductive line 16. A first conductive line 16 and a second conductive line 17 are connected in series through a first conductive body 14 and a second conductive body 15 to form a temperature-sensing circuit. This temperature-sensing circuit has a chain-like structure, meaning that one end of the first conductive body 14 is electrically connected to the first conductive line 16, and the other end of the first conductive body 14 is electrically connected to the second conductive line 17. The other end of the second conductive line 17, which is electrically connected to the first conductive body 14, is electrically connected to the second conductive body 15. The other end of the second conductive body 15, which is electrically connected to the second conductive line 17, is electrically connected to another first conductive line 16. The other end of the first conductive line 16, which is electrically connected to 15, is electrically connected to another first conductor 14. The other first conductor 14 is electrically connected to another second conductive line 17. This process is repeated to form a series circuit with a hole chain structure consisting of the first conductive line 16, the first conductor 14, the second conductive line 17, and the second conductor 15. In this hole chain structure temperature sensing circuit, the potential differences generated by multiple first conductors 14 and multiple second conductors 15 in the cold and heat sources can be superimposed, which is beneficial to increasing the voltage difference of the entire temperature sensing circuit in the cold and heat sources.

[0050] Step S6: Please refer to Figure 6 An insulating layer 18 is provided, which covers the surfaces of the first conductor 14 and the first conductive line 16 that are away from the first substrate layer 11. In this embodiment, the insulating layer 18 can be made of a transparent polyester polymer film or a transparent solder resist ink. The thickness of the insulating layer 18 can be 20μm to 100μm.

[0051] Step S7: Please refer to Figure 7A first dielectric substrate 191 is disposed on the surface of the first substrate layer 11 opposite to the second conductive line 17. The first dielectric substrate 191 covers the first substrate layer 11 and exposes the surfaces of the first conductor 14 and the first conductive line 16. A second dielectric substrate 192 is disposed on the surface of the first substrate layer 11 opposite to the first dielectric substrate 191. The second dielectric substrate 192 covers the first substrate layer 11 and exposes the surfaces of the second conductive line 17 and the second conductor 15. In this embodiment, the first dielectric substrate 191 also covers an insulating layer 18 and exposes it on the surface of the first substrate layer 11, such that the insulating layer 18, the first conductor 14, the first conductive line 16, the second conductive line 17, and the second conductor 15 are embedded within the first dielectric substrate 191 and the second dielectric substrate 192. This results in the first circuit board 1.

[0052] Step S8: Please refer to Figure 8 A second substrate 20 is provided, which includes a second substrate layer 21 and a third conductive layer 22, wherein the third conductive layer 22 is disposed on one surface of the second substrate layer 21. In this embodiment, the second substrate 20 is a single-sided copper-clad laminate, the material of the second substrate layer 21 can be a transparent flexible material such as polyimide (PI) or polyethylene naphthalate (PEN), and the third conductive layer 22 is copper foil.

[0053] Step S9: Please refer to Figure 9 The third conductive layer 22 is etched to obtain the first slot 221 and the third conductive line 222. The first slot 221 penetrates the third conductive layer 22, so that part of the second substrate layer 21 is exposed in the first slot 221.

[0054] Step S10: Please refer to Figure 10 A strain resistance layer 23 is disposed within the first groove 221. The strain resistance layer 23 covers the surface of the second substrate layer 21 on which the third conductive line 222 is disposed, and a portion of the second substrate layer 21 is exposed in the strain resistance layer 23. The strain resistance layer 23 is made of conductive polymers, conductive carbon materials, and metals, etc. The conductive polymer can be poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate (PEDOT:PSS) or polypyrrole, etc., and the conductive carbon material can be graphene, carbon nanotubes, etc.

[0055] Step S11: Please refer to Figure 11A third dielectric substrate 24 is applied to the surface of the strain resistor layer 23 facing away from the second substrate layer 21. The third dielectric substrate 24 covers the surface of the third conductive line 222, a portion of the strain resistor layer 23, and a portion of the second substrate layer 21. A plurality of second slots 241 are formed on the side of the third dielectric substrate 24 facing away from the strain resistor layer 23, penetrating the third dielectric substrate 24, and the plurality of second slots 241 are spaced apart. This process yields the second circuit board 2.

[0056] Step S12: Please refer to Figure 12 A third substrate 30 is provided, the third substrate 30 includes a third substrate layer 31 and a fourth conductive layer 32, the fourth conductive layer 32 being disposed on a surface of the third substrate layer 31.

[0057] In this embodiment, the third substrate 30 is a single-sided copper-clad laminate, the material of the third substrate layer 31 can be a transparent and flexible material such as polyimide (PI) or polyethylene naphthalate (PEN), and the fourth conductive layer 32 is copper foil.

[0058] Step S13: Please refer to Figure 13 The fourth conductive layer 32 is etched to obtain the third groove 321 and the fourth conductive line 322. The third groove 321 penetrates the fourth conductive layer 32, so that part of the third substrate layer 31 is exposed at the bottom of the third groove 321.

[0059] Step S14: Please refer to Figure 14 A humidity sensing layer 33 is provided in the third slot 321. The humidity sensing layer 33 covers the surface of the third substrate layer 31 where the fourth conductive line 322 is provided. The humidity sensing layer 33 is electrically connected to the fourth conductive line 322.

[0060] In this embodiment, the humidity sensing layer 33 is made of nanoparticles such as titanium dioxide that generate electrical signal changes due to moisture absorption, and a conductive polymer (such as PEDOT:PSS). Nanoparticles such as titanium dioxide that generate electrical signal changes due to moisture absorption are uniformly dispersed within the conductive polymer and then spin-coated onto the surface of the third substrate layer 31 near the fourth conductive line 322, thereby obtaining the humidity sensing layer 33. The humidity sensing layer 33 contains nanoparticles that generate electrical signal changes due to moisture absorption, thus enabling it to sense external humidity and convert it into an electrical signal. Furthermore, the sensitivity of the humidity sensing layer 33 can be adjusted by controlling the size and proportion of the nanoparticles. Additionally, the humidity sensing layer 33 obtained through spin-coating exhibits excellent uniformity, which improves its stability and sensitivity.

[0061] Step S15: Please refer to Figure 15A fourth dielectric substrate 34 is disposed on the fourth conductive line 322 and the humidity sensing layer 33, and the fourth dielectric substrate 34 covers the surface of the fourth conductive line 322 and the humidity sensing layer 33 that is away from the third substrate layer 31. The third circuit board 3 is thus obtained.

[0062] Step S16: Please refer to Figure 16 The second circuit board 2, with the side having the third dielectric base layer 24, is pressed against the side of the first circuit board 1 having the insulating layer 18, so that the insulating layer 18 is embedded in the second slot 241 of the second circuit board 2, and the first dielectric base layer 191 is connected to the third dielectric base layer 24 to form the first dielectric layer 4. The third circuit board 3, with the side having the fourth dielectric base layer 34, is pressed against the side of the first circuit board 1 having the second conductor 15, so that the fourth dielectric base layer 34 is connected to the second dielectric base layer 192 to form the second dielectric layer 5. This yields the flexible sensor 100.

[0063] Please see Figure 16 This application also provides a flexible sensor 100, including a first circuit board 1, a second circuit board 2, and a third circuit board 3. The first circuit board 1 includes a first substrate layer 11, a plurality of first conductive lines 16, a plurality of second conductive lines 17, a first conductor 14, and a second conductor 15. The plurality of first conductive lines 16 are spaced apart on one side of the first substrate layer 11, and the plurality of second conductive lines 17 are spaced apart on the side of the first substrate layer 11 opposite to the first conductive lines 16. The first conductor 14 and the second conductor 15 are spaced apart, with the first conductor 14 penetrating the first substrate layer 11 and electrically connected to the first conductive lines 16 and the second conductive lines 17, and the second conductor 15 penetrating the first substrate layer 11 and electrically connected to the first conductive lines 16 and the second conductive lines 17. The first conductor 14 and the second conductor 15 electrically connect the plurality of spaced first conductive lines 16 and the plurality of spaced second conductive lines 17 in series. The second circuit board 2 is located on one side of the first circuit board 1, and the second circuit board 2 is provided with a strain gauge layer 23. The third circuit board 3 is located on the side of the first circuit board 1 away from the second circuit board 2, and the third circuit board 3 includes a humidity sensing layer 33.

[0064] In this application, the first circuit board 1 is a temperature sensing layer for detecting temperature; the second circuit board 2 is a pressure sensing layer for detecting the magnitude of external force; and the third circuit board 3 is a humidity sensing layer for detecting humidity. The detection signals of each layer are output independently by each sensing layer, ensuring that the detection signals from each layer do not interfere with each other. Furthermore, the sensitivity curve of the pressure sensing layer is easily affected by temperature changes. Measuring temperature changes through the temperature sensing layer can effectively assist in correcting the detection of external force, thereby reducing the influence of temperature on the pressure sensing layer and further improving its sensitivity.

[0065] Along the thickness direction A, the pressure sensing layer is located on the outermost layer of the flexible sensor 100, which helps to improve its sensitivity and accuracy in detecting external forces, and reduces the impact of rapid changes in ambient temperature on the accuracy of the temperature sensing layer. The temperature sensing layer and humidity sensing layer are located in the inner layers of the flexible sensor 100, and can directly adhere to the surface of the object to be measured to detect its humidity and temperature, reducing interference from rapid changes in the external environment that could affect the accuracy of detection. Therefore, the design of the various functional sensing layers of the flexible sensor 100 in this application can mutually assist each other to improve sensitivity and sensing accuracy.

[0066] In some embodiments, the first conductor 14 protrudes from the surface of the first substrate layer 11 away from the surface of the second conductive line 17, and the second conductor 15 protrudes from the surface of the first substrate layer 11 away from the surface of the first conductive line 16. Please refer to... Figure 16 In the first circuit substrate 1, the first conductor 14 forms a raised fence-like structure on the surface of the first substrate layer 11 away from the second conductive line 17. This structure can increase the stretching of the strain resistance layer 23 of the second circuit substrate 2 after the flexible sensor 100 is subjected to external force, thereby further improving the pressure sensing sensitivity of the second circuit substrate 2.

[0067] In some embodiments, the flexible sensor 100 further includes a first dielectric layer 4 and a second dielectric layer 5. The first dielectric layer 4 is located between the strain gauge layer 23 and the first substrate layer 11, and the second dielectric layer 5 is located between the first substrate layer 11 and the humidity sensing layer 33. The first dielectric layer 4 includes a first dielectric base layer 191 and a third dielectric base layer 24, and the second dielectric layer 5 includes a second dielectric base layer 192 and a fourth dielectric base layer 34. The first dielectric layer 4 and the second dielectric layer 5 serve to protect the circuitry and adhere the various functional sensing layers.

[0068] In some embodiments, the flexible sensor 100 further includes an insulating layer 18 that covers the surfaces of the first conductor 14 and the first conductive line 16 facing away from the second conductive line 17. The thickness of the insulating layer 18 is 20 μm to 100 μm. This thickness range is advantageous for forming a raised grid-like structure and for maintaining an appropriate thickness of the flexible sensor 100.

[0069] In some embodiments, the strain resistance layer 23 is made of at least one of conductive polymers, conductive carbon materials, and metals. Choosing a suitable material for the strain resistance layer 23 is beneficial for converting changes in force into electrical signals and improving the sensitivity and accuracy of the flexible sensor 100 in detecting external forces.

[0070] In some embodiments, the first conductor 14 is made of copper, and the second conductor 15 is made of a copper-nickel alloy. A potential difference can be generated between the copper and the copper-nickel alloy to convert the hot / cold signal into an electrical signal, thereby improving the sensitivity and accuracy of the flexible sensor 100 in detecting temperature.

[0071] In some embodiments, the humidity sensing layer 33 is made of titanium dioxide nanoparticles and a conductive polymer. The titanium dioxide nanoparticles and the conductive polymer can convert humidity changes into electrical signal changes, thereby improving the sensitivity and accuracy of the flexible sensor 100 in detecting humidity.

[0072] In some embodiments, the first dielectric layer 4 and the second dielectric layer 5 are made of at least one of polydimethylsiloxane (PDMS), thermoplastic polyurethane (TPU), and pressure-sensitive adhesives (PSA). Conventional adhesives that require high-temperature curing can have their transparency affected by high temperatures. In this embodiment, the first dielectric substrate 191 and the second dielectric substrate 192 are made of transparent adhesives such as polydimethylsiloxane, thermoplastic polyurethane elastomer, or pressure-sensitive adhesives. These materials can be bonded using a low-temperature curing method, thus reducing energy consumption costs during the manufacturing process while maintaining the transparency of the materials.

[0073] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application should not depart from the spirit and scope of the technical solutions of this application.

Claims

1. A flexible sensor, characterized in that, include: A first circuit board includes a first substrate layer, a plurality of first conductive lines, a plurality of second conductive lines, a first conductor, and a second conductor. The plurality of first conductive lines are spaced apart on one side of the first substrate layer, and the plurality of second conductive lines are spaced apart on the side of the first substrate layer opposite to the first conductive lines. The first conductor and the second conductor are spaced apart. The first conductor penetrates the first substrate layer and is electrically connected to the first conductive lines and the second conductive lines. The second conductor penetrates the first substrate layer and is electrically connected to the first conductive lines and the second conductive lines. The first conductor and the second conductor electrically connect the plurality of spaced first conductive lines and the plurality of spaced second conductive lines in series. The second circuit board is located on one side of the first circuit board, and the second circuit board is provided with a strain resistance layer. The third circuit board is located on the side of the first circuit board away from the second circuit board, and the third circuit board is provided with a humidity sensing layer.

2. The flexible sensor as described in claim 1, characterized in that, The flexible sensor further includes a first dielectric layer and a second dielectric layer, wherein the first dielectric layer is located between the strain resistor layer and the first substrate layer, and the second dielectric layer is located between the first substrate layer and the humidity sensing layer.

3. The flexible sensor as described in claim 1, characterized in that, The first conductor protrudes from the surface of the first substrate layer away from the surface of the second conductive line, and the second conductor protrudes from the surface of the first substrate layer away from the surface of the first conductive line.

4. The flexible sensor as described in claim 1, characterized in that, The strain resistance layer is made of at least one of conductive polymers, conductive carbon materials, and metals.

5. The flexible sensor as described in claim 1, characterized in that, The first conductor is made of copper, and the second conductor is made of a copper-nickel alloy.

6. The flexible sensor as described in claim 1, characterized in that, The humidity sensing layer is made of titanium dioxide nanoparticles and conductive polymers.

7. The flexible sensor as described in claim 2, characterized in that, The materials of the first dielectric layer and the second dielectric layer include at least one of polydimethylsiloxane, thermoplastic polyurethane elastomer, and pressure-sensitive adhesive.

8. A method for fabricating a flexible sensor, characterized in that, Includes the following steps: A first circuit board is provided, the first circuit board including a first substrate layer, a plurality of first conductive lines, a plurality of second conductive lines, a first conductor and a second conductor, the plurality of first conductive lines being spaced apart on one side of the first substrate layer, the plurality of second conductive lines being spaced apart on the side of the first substrate layer opposite to the first conductive lines, the first conductor and the second conductor being spaced apart, the first conductor penetrating the first substrate layer and electrically connected to the first conductive lines and the second conductive lines, the second conductor penetrating the first substrate layer and electrically connected to the first conductive lines and the second conductive lines, the first conductor and the second conductor electrically connecting the plurality of spaced first conductive lines and the plurality of spaced second conductive lines in series; A second circuit board is provided, which is located on one side of the first circuit board, and the second circuit board is provided with a strain resistance layer. A third circuit board is provided, the third circuit board being located on the side of the first circuit board away from the second circuit board, and the third circuit board is provided with a humidity sensing layer. The first circuit board, the second circuit board, and the third circuit board are stacked in sequence.

9. The method for fabricating a flexible sensor as described in claim 8, characterized in that, The first conductor is made of copper, and the second conductor is made of a copper-nickel alloy.

10. The method for fabricating a flexible sensor as described in claim 8, characterized in that, The humidity sensing layer is made of titanium dioxide nanoparticles and conductive polymers.

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