Inductive flexible strain sensor with slotted array and method of manufacture

Abstract

This invention discloses an inductive flexible strain sensor with a slot array and its fabrication method, comprising: a flexible substrate; a slot array structure, wherein the slot array structure includes multiple staggered through slots arranged on the flexible substrate, the slots being arranged as a horizontal or vertical extension of basic staggered slot unit structures; an inductive circuit, wherein the inductive circuit is bent and disposed on the flexible substrate, bypassing the slot array structure, so that the inductive circuit intersects and surrounds the slot array structure, and the inductive circuit deforms with the substrate when the substrate is stretched; and a protective layer, wherein the protective layer covers and protects the area where the inductive circuit is located. Due to the presence of the slot array, this invention significantly improves the strain detection range of the structure, and the inductive strain detection method overcomes the problem of insufficient sensitivity in traditional flexible circuit resistance detection methods, enabling the structure to be applied to high-sensitivity, large-range strain detection.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to an inductive flexible strain sensor with a slot array and its fabrication method. Background Technology

[0002] In existing technologies, strain sensors struggle to achieve both high sensitivity in strain detection and a large detection range. Currently, flexible sensors based on surface cracks can achieve highly sensitive strain detection, but their detectable strain range is limited. When an applied stimulus causes the surface crack to fracture, the conductive material on the surface does not come into contact, and the sensor reaches its maximum strain detection range. Flexible strain sensors based on ultra-stretchable materials can achieve a detection range several times or even tens of times their own length. However, ultra-stretchable materials are greatly affected by environmental factors, their acquisition process is cumbersome, and the signal detection method is complex, making it difficult to achieve both high sensitivity in strain detection and detection in complex environments.

[0003] Therefore, existing sensor technologies still need further improvement and development. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide an inductive flexible strain sensor with slot array and a method for its fabrication, aiming to solve the problem that existing sensors cannot simultaneously achieve high-sensitivity strain detection and large-range strain detection.

[0005] The technical solution of the present invention is as follows:

[0006] A first aspect of the present invention provides an inductive flexible strain sensor with a slotted array, comprising:

[0007] Flexible substrate

[0008] A seam array structure, comprising multiple staggered through seam structures arranged on the flexible substrate, wherein the seam structures are arranged in a horizontal or vertical extension of the basic staggered seam unit structure;

[0009] An inductor circuit is bent and disposed on the flexible substrate, avoiding the slot array structure, so that the inductor circuit passes through and surrounds the slot array structure. When the substrate is stretched, the inductor circuit deforms with the substrate.

[0010] A protective layer that covers and protects the area where the inductor circuit is located.

[0011] The aforementioned inductive flexible strain sensor with slotted array, wherein the basic staggered slot unit structure is arranged as follows: three slots a, b, and c are arranged parallel to the x-axis, the center positions of slots a and b are equidistant from the x-axis, slot c is spaced apart from slots a and b in the y-direction, the midpoint of the line connecting the adjacent tips of slots a and b is connected to the center of slot c, and the connecting line is perpendicular to the x-axis, and the three slots are staggered.

[0012] The aforementioned inductive flexible strain sensor with a slot array, wherein the slot tip of the slot array structure is circular, and the diameter of the circle is greater than or equal to the width of the slot.

[0013] The aforementioned inductive flexible strain sensor with slot array, wherein the inductive circuits arranged on both sides of the slot structure are arranged in a serpentine circuit arrangement or a loop circuit arrangement.

[0014] The aforementioned inductive flexible strain sensor with slotted array, wherein the protective layer is made of a flexible material.

[0015] The aforementioned inductive flexible strain sensor with slotted array, wherein the flexible substrate is a bendable substrate.

[0016] The aforementioned inductive flexible strain sensor with slotted array, wherein,

[0017] The boundary shape of the flexible substrate is rectangular, convex, or concave.

[0018] The aforementioned inductive flexible strain sensor with slotted array, wherein the bending angle of the inductive circuit is: a 90-degree right angle, an arc-shaped angle, or a polygonal angle.

[0019] The inductive flexible strain sensor with slotted array is wherein the flexible substrate is made of PDMS material, polyimide film, or paper.

[0020] A method for fabricating an inductive flexible strain sensor with a slotted array as described in any one of the claims, comprising the steps of:

[0021] Flexible substrate fabrication steps: A flexible substrate film is prepared on a planar substrate. The thickness of the substrate film is controlled according to the preparation process parameters to form a flexible substrate.

[0022] Inductor circuit fabrication steps: The designed metal circuit is fabricated on a flexible substrate. The metal circuit includes two parts: inductor circuit and metal contacts.

[0023] Protective layer fabrication steps: A flexible protective layer is fabricated above the inductor circuit, covering the inductor circuit portion and exposing the metal contact portion;

[0024] Slot array structure etching steps: A slot array structure is etched on a flexible substrate on which the inductor circuit has been fabricated. The slots of the slot array structure penetrate the protective layer and the flexible substrate layer.

[0025] Sensor fabrication steps: The flexible substrate film and metal circuit on the planar substrate are diced and sliced. The sliced ​​sensor is then peeled off from the planar substrate, and the fabrication is complete.

[0026] Beneficial Effects: This invention provides an inductive flexible strain sensor with a slot array and its fabrication method. When an external deformation stimulus causes the flexible substrate of the sensor to deform, the slot array structure is stretched and deformed. Due to the presence of the slot array, the substrate material transforms in-plane stretching into out-of-plane bending, greatly increasing the tensile strength of the structure and expanding the detectable strain range. The inductive circuits located around the slot array change their spacing due to substrate deformation, leading to a change in the circuit's self-inductance. By detecting the degree of change in the circuit's self-inductance, the magnitude of the strain is determined. Compared to traditional strain detection methods that add resistors to a flexible substrate and rely on structural deformation to change resistance, the inductive detection method converts the distance change on both sides of the slot structure into a change in the circuit's inductance, resulting in higher sensitivity. The combination of the slot array and the inductive detection circuit gives the flexible sensor higher sensitivity and a wider detection range. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of an inductive flexible strain sensor with a slotted array according to an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of an inductive flexible strain sensor layer structure with a slotted array according to an embodiment of the present invention.

[0029] Figure 3 This is a tensile schematic diagram of a slotted substrate for an inductive flexible strain sensor with a slotted array, according to an embodiment of the present invention.

[0030] Figure 4 This is a schematic diagram of the tensile deformation of a single slot in an inductive flexible strain sensor with a slot array according to an embodiment of the present invention.

[0031] Figure 5 This is a schematic diagram of the slot array parameters of an inductive flexible strain sensor with a slot array according to an embodiment of the present invention.

[0032] Figure 6 This is a schematic diagram of a single slit tip of an inductive flexible strain sensor with a slit array according to an embodiment of the present invention.

[0033] Figure 7 This is a schematic diagram illustrating the change in the distance between adjacent inductors of an inductive flexible strain sensor with a slotted array according to an embodiment of the present invention.

[0034] Figure 8 This invention provides a loop-shaped inductor circuit for an inductor-flexible strain sensor with a slotted array, as described in an embodiment of the present invention.

[0035] Figure 9 This invention relates to a flexible substrate boundary shape for an inductive flexible strain sensor with a slotted array, as described in an embodiment of the present invention.

[0036] Figure 10 This is a flowchart illustrating the fabrication process of an inductive flexible strain sensor with a slotted array, according to an embodiment of the present invention. Detailed Implementation

[0037] This invention provides an inductive flexible strain sensor with a slotted array and its fabrication method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0038] 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 this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0039] Please refer to the accompanying drawings for some embodiments of an inductive flexible strain sensor with a slot array.

[0040] like Figure 1 and Figure 2 As shown, an inductive flexible strain sensor with a slot array according to the present invention includes: a flexible substrate 1, a slot array structure 2 etched on the flexible substrate 1, an inductive circuit 3 attached to the flexible substrate 1, and a protective layer 4 covering the inductive circuit 3.

[0041] Embodiments of the present invention, such as Figure 3 As shown, the slot array structure 2 includes multiple staggered through slot structures 21 arranged on the flexible substrate 1; the inductor circuit 3 avoids the slot array structure 2 and is bent and arranged on the flexible substrate 1.

[0042] The flexible substrate 1 is made of a material with a low elastic modulus or a relatively thin material, allowing it to bend under stress. This facilitates the etching of the slit array structure 2, the addition of inductive circuits 3, and the addition of a protective layer 4 onto the flexible substrate 1. Specifically, the flexible substrate 1 can be made of PDMS, polyimide film, or other flexible and bendable materials such as paper. The length, width, and thickness of the flexible substrate 1 are determined according to the requirements of the application scenario.

[0043] As can be seen, the inductive flexible strain sensor with slot array in this embodiment of the invention employs a flexible and bendable substrate, an array of slot structures etched on the substrate, an inductive circuit for sensing substrate deformation, and a protective layer. Its key feature is that slot array structures with different parameter arrangements are etched or scribed on the flexible substrate, the inductive circuit surrounds the slot array structure, and the deformation of the flexible substrate material is detected using an inductive detection method.

[0044] The detection mechanism of the inductive flexible strain sensor with slotted array in this invention is as follows: When the deformation of the object to be detected causes deformation of the flexible strain sensor, the self-inductance of the circuit on the flexible substrate changes. By detecting the change in self-inductance, the degree of deformation of the sensor is determined. The self-inductance of the circuit on the sensor substrate: According to Biot-Savart's law, when current flows through the metal wire on the sensor substrate, a gradually decreasing magnetic field is generated around the wire. The magnetic field around the current-carrying wire is calculated as shown in Formula 1:

[0045]

[0046] Where μ0 is a constant, I is the current, and R is the distance from the selected point to the conductor. The farther the point is from the conductor, the smaller the magnetic field generated by the conductor. According to Faraday's law of electromagnetic induction, when the current in the circuit changes, the magnetic field around the conductor changes, thus producing a change in magnetic flux. This change in magnetic flux leads to an induced electromotive force (EMF) in the conductor, and this EMF always opposes the original change in the current in the conductor. The induced EMF is called the self-induced EMF, and it is calculated as shown in Formula 2:

[0047]

[0048] Where ΔI represents the change in current in the conductor, Δt represents the change in time, and L represents the self-inductance of the circuit. The magnitude of the self-inductance L depends only on the geometry of the circuit coil, the number of turns, and the properties of the surrounding medium. The longer the coil, the more turns per unit length, and the larger the cross-sectional area, the greater the self-inductance. For the sensor in this patent, when the flexible substrate with the slotted structure is stretched, such as... Figure 7As shown, the substrate deforms, and the two sides of the slot structure are stretched, transforming in-plane stretching into out-of-plane bending. This increases the distance between the conductors on both sides of the slot structure from d0 to d1. The increased distance reduces the influence of the magnetic field between the circuits, lowering the circuit's inductance. Therefore, the deformation of the sensor itself can be detected by detecting inductance. When an external deformation stimulus causes the flexible substrate of the sensor to deform, the slot array structure is stretched and deformed. Due to the presence of the slot array, the substrate material transforms in-plane stretching into out-of-plane bending, significantly increasing the structural stretching and expanding the detectable strain range. Compared to the traditional strain detection method that adds resistance to a flexible substrate and uses structural deformation to change resistance, the inductance detection method converts the change in distance between the two sides of the slot structure into a change in the circuit inductance, resulting in higher sensitivity. The combination of the slot array and the inductance detection circuit gives the flexible sensor higher sensitivity and a wider detection range.

[0049] In embodiments of the present invention, such as Figure 4 As shown, a protective layer 4 can be provided above the entire flexible substrate 1, including the inductor circuit 3. Of course, in other embodiments, the protective layer 4 may not cover the entire inductor circuit 3, but only the inductor circuit 3.

[0050] In this embodiment of the invention, the arrangement of the seam structure 21 is an extension of the basic staggered seam unit structure in the horizontal or vertical direction, such as... Figure 1 As shown, the basic staggered seam unit structure is arranged as follows: three seams a, b, and c are arranged parallel to the x-axis; the center positions of seams a and b are equidistant from the x-axis; seam c is spaced apart from seams a and b in the y-direction; the midpoint of the line connecting the adjacent tips of seams a and b is connected to the center of seam c, and this line is perpendicular to the x-axis; the three seams are arranged in a staggered manner. Thus, in this embodiment of the invention, as... Figure 3 As shown in Figure b, when the flexible substrate containing the slot array is stretched, the presence of the staggered slot structure 21 causes out-of-plane bending of the flexible substrate on both sides of the slot structure 21, increasing the opening angle of the slot structure 21 and enhancing the stretchability of the flexible substrate. The increased distance between the inductor circuits located on both sides of the slot structure 21 causes a change in the inductance value of the circuit.

[0051] In this embodiment of the invention, preferably, the slot array structure 2 refers to a through-slot structure with certain dimensional parameters etched onto the flexible substrate 1 and the protective layer 4. For example... Figure 3 As shown, due to the presence of the slot array structure 2, when the flexible substrate 1 is subjected to tensile load, the flexible substrates on both sides of the slot are released by the penetrating slot structure. Due to the flexible substrate's bendability, in-plane tension is transformed into out-of-plane bending. Figure 4As shown, the deformation on both sides of the seam manifests as one side bending upwards and the other side bending downwards. Specifically, when the parameters of the seam array are changed, the deformation on both sides of the seam can also manifest as bending to the same side. Due to the presence of the seam array, the deformations of the flexible substrate are superimposed, thus the seam array structure 2 greatly increases the deformation range of the flexible substrate material.

[0052] In this embodiment of the invention, an inductor circuit 3 is located on a flexible substrate 1, and the inductor circuit 3 intersects and surrounds the slot array structure 2. When the flexible substrate is stretched, the inductor circuit 3 deforms along with the flexible substrate. In this embodiment, the flexible substrate 1 contains at least one set of inductor circuits for detecting the strain of the sensor. Specifically, the flexible substrate contains multiple sets of inductor circuits, which cooperate with each other to sense the strain at different locations on the flexible substrate, and can detect the stretching, curling, and torsion of the flexible substrate.

[0053] In one embodiment, the slot array structure 2 of the present invention includes at least one slot structure 21 penetrating the flexible substrate 1 and the protective layer 4. Combinations of slot structures with different parameters cause different deformations in the flexible substrate. The slot structure parameters vary depending on the application scenario. Variable parameters include: the number of basic staggered slot unit structures in the x and y directions, the length of the transverse slot, the slot width, the transverse spacing of the slots, the longitudinal spacing of the slots, the distance between the boundary slots and the substrate boundary, the width and thickness of the inductor circuit, the transverse and longitudinal distances between the inductor circuit and the slots, and the size, position, and shape of the circuit poles.

[0054] Specifically, different parameters of the slot array structure 2 will have different effects on the deformation of the structure after stretching. For example... Figure 5 As shown, the parameters of the slot array structure 2 include: the number of basic staggered slot unit structures in the x and y directions, the transverse slot length l, the slot width w, the transverse slot spacing w0, the longitudinal slot spacing h0, and the distance w1 between the boundary slot and the base boundary. The parameters of the inductor circuit 3 include: the width w2 and thickness t2 of the inductor circuit 3, the transverse distance w2 and longitudinal distance h1 between the inductor circuit 3 and the slots, and the size, position, and shape of the circuit poles. All of these parameters can be designed as variables. Depending on the application scenario, the parameters of the slot array structure 2 can be designed. For example, if it is necessary to improve the tensile performance of the structure, the slot density needs to be increased: such as increasing the transverse slot length l and decreasing the longitudinal slot spacing h.

[0055] In this embodiment of the invention, to improve the stretchability of the flexible substrate 1, the slit tips of the slit array structure 2 on the flexible substrate 1 are designed to be circular, with the diameter of the circle being greater than or equal to the width of the slit, such as... Figure 6 As shown, Figure 6This is a schematic diagram of a single slot tip in an inductive flexible strain sensor with a slot array according to an embodiment of the present invention. When the flexible substrate with slots is stretched and deformed, the deformation endpoint of the slot structure 21 is at the tip positions on both sides of the slot. To increase the tensile force that the slot structure can withstand, the tip is designed to be circular, which can concentrate the stress more evenly on the arc-shaped tip. This increases the tensile range of the structure.

[0056] This invention discloses an inductive flexible strain sensor with a slotted array. The inductive circuits on the flexible substrate are arranged in a slotted structure, with inductive circuits on both sides of the slotted structure. The inductive circuits can be arranged in a serpentine or a U-shape. Different inductive circuit arrangements respond differently to different substrate deformations. A serpentine arrangement is better for detecting tensile stress on the substrate, while a U-shape arrangement is better for detecting overall bending. The circuit arrangement is determined based on the requirements of the detection scenario. The corners of the inductive circuits can be set as: 90-degree right angles, arc corners, or polygonal corners.

[0057] Specifically, since the slot array structure is disposed on the flexible substrate, the present invention detects the material deformation of the flexible substrate 1 by employing an inductive circuit 3, such as... Figure 7 As shown, inductor circuits 3 are arranged on both sides of the slot structure. For a serpentine circuit arrangement, when inductor circuit 3 is energized, the current directions in adjacent circuits are opposite, and the resulting magnetic field affects the flow of internal current, generating inductance. When the flexible substrate 1 containing the slot structure 21 is stretched, the flexible substrate 1 deforms, and the two sides of the slot structure 21 are stretched. The increased deformation leads to an increased distance between the circuits on both sides of the slot structure 21, thus reducing the influence of the magnetic field and lowering the inductance value. Traditional strain detection methods involve resistance detection, where resistive circuits are arranged on the flexible substrate 1. When the structure is stretched, the structural parameters of the resistor change, and the resistance value changes. However, when the flexible substrate 1 containing the slot structure 21 is stretched, in-plane stretching transforms into out-of-plane bending. The effect of in-plane stretching, which significantly affects resistance changes, is reduced. Therefore, the resistance change is not significant when the flexible substrate 1 bends. Compared with traditional resistance detection methods, this inductance detection method improves the sensitivity of flexible substrate deformation detection.

[0058] In one implementation, Figure 1 The middle section contains two sets of serpentine inductor circuits 3. The inductor circuits 3 bend at the tip of the slot structure 21 and serpentine through each slot structure 21. The lead-out poles of the inductor circuits 3 are located on both sides of the inductor circuit. Since the current direction between the two closest circuits is opposite, the stretching of each slot structure 21 will affect the inductor. Therefore, the serpentine inductor circuits 3 have higher sensitivity.

[0059] In another embodiment of the present invention, such as Figure 8As shown, Figure 8 The middle part is a set of inductor circuits arranged in a loop (such as...) Figure 8 (31) The inductor circuit wraps around both edges of the flexible substrate, passing through each aperture (e.g.) Figure 8 As shown in 21), in the circuit with a U-shaped arrangement, the current direction in the inductor circuits on both sides of the slits in the upper and lower parts is the same. At this time, the deformation caused by the stretching of a single slit has little impact on the overall inductance. However, the current direction between the inductor circuits that are symmetrical with respect to the center is opposite. Therefore, the bending of the overall structure has a greater impact on the circuit's inductance. Thus, the U-shaped arrangement of the inductor circuit is sensitive to the overall bending of the flexible substrate. Based on the sensor's detection requirements, the arrangement positions and densities of the two arrangement methods on the flexible substrate are determined. For example, if the application scenario requires detecting the stretching on both sides of the substrate and the bending in the middle of the substrate, a serpentine arrangement is used on both sides of the substrate, and a U-shaped arrangement is used in the center of the substrate. When the substrate transforms the stretching deformation into torsion due to different slit array arrangements, two sets of axially symmetrical serpentine circuits are used to detect the torsion of the flexible substrate.

[0060] In one embodiment, the bending corner of the inductor circuit 3 can be a 90-degree right angle, an arc corner, or a polygonal corner. Different corner designs have different effects on the inductor circuit 3 when subjected to tension, and the corner design can be determined based on the application scenario and manufacturing process. If the structure needs to withstand large stretching, the circuit corner is designed as an arc corner or a polygonal corner. Since the stress of arc corners and polygonal corners can be distributed at the corner edge when subjected to tension, the stress concentration is reduced compared to right-angle corners, thus improving the tensile strength of the structure.

[0061] In one embodiment, the protective layer 4 of the present invention covers the inductor circuit 3 for dustproofing, waterproofing, and isolating external interference. The protective layer 4 includes a porous structure with material parameters consistent with the flexible substrate 1, and the electrode positions of the inductor circuit do not contain the protective layer. Specifically, the protective layer 4 is made of a flexible material, and the material used to make the protective layer 4 can be the same as or different from the material used to make the flexible substrate 1. The function of the protective layer 4 is to protect the inductor circuit 3 from breakage when the flexible substrate 1 is stretched, and at the same time, the material of the flexible substrate 1 protects the inductor circuit 3 from external signal interference, thus providing dustproof and waterproof protection.

[0062] In one embodiment, the flexible substrate 1 is a bendable substrate, and the boundary shape of the flexible substrate 1 is designed according to the usage scenario as a rectangle, a convex shape, a concave shape, or a combination of the above shapes. Figure 9As shown, the convex flexible substrate boundary design, due to its longer lateral length of the seam, results in greater deformation during tension, thus improving the structure's sensitivity. The concave flexible substrate boundary design, under tension, has a smaller substrate width at the center, causing deformation and bending primarily to occur at the center. Combined with different circuit arrangements, this can enhance the sensor's detection range.

[0063] As can be seen, the inductive flexible strain sensor with a slot array provided in this embodiment of the invention employs a flexible and bendable substrate, an array of slot structures etched on the flexible substrate, an inductive circuit for sensing substrate deformation, and a protective layer. When the flexible substrate with the slot array reaches tensile strain, the presence of the slot array transforms the in-plane stretching of the substrate into out-of-plane bending, significantly increasing the tensile strength of the structure and expanding the detectable strain range. Due to the substrate deformation, the spacing of the inductive circuits located around the slot array changes, leading to a change in the self-inductance of the circuits. By detecting the degree of change in the self-inductance value, the magnitude of the strain is determined. The presence of the slot array greatly enhances the strain detection range of the structure. The inductive strain detection method overcomes the insufficient sensitivity of traditional flexible circuit resistance detection methods, enabling the structure to be applied to highly sensitive, large-range strain detection.

[0064] The inductive flexible strain sensor based on the slotted array described in the above embodiments, such as Figure 10 As shown, the present invention also provides a method for fabricating an inductive flexible strain sensor with a slot array, comprising the following steps:

[0065] Step S1, Flexible substrate fabrication: A flexible substrate film is prepared on a planar substrate (such as a silicon wafer, glass substrate, etc.) by spin coating, sputtering, spraying, etc. The thickness of the substrate film can be controlled according to the process parameters to form a flexible substrate.

[0066] Step S2, Inductor Circuit Fabrication: The designed metal circuit is fabricated on a flexible substrate using methods such as screen printing, photolithography, ion sputtering, spraying, and peeling. The metal circuit includes two parts: inductor circuit and metal contacts.

[0067] Step S3, Prepare the protective layer: Based on the first two steps, a flexible protective layer is prepared by spraying, pressing, spin coating and other methods. The flexible protective layer covers the inductor circuit part and exposes the metal contact part.

[0068] Step S4, Slot Array Structure Etching: A slot array structure is etched onto the flexible substrate on which the inductor circuit has been fabricated. The slots in the slot array structure penetrate the protective layer and the flexible substrate layer. Specifically, for example, etching / scribing the slot array: The designed slot array is fabricated on the prepared material using methods such as laser ablation, scribing, or solution etching. The slot array penetrates the protective layer and the flexible substrate layer.

[0069] Step S5, Sensor Segmentation Fabrication Step: The flexible substrate film and metal circuit located on the planar substrate are diced and segmented, and the segmented sensor located on the planar substrate is peeled off, thus completing the fabrication.

[0070] In this embodiment of the invention, the fabrication method allows for the design of slot structures with different array parameters on planar substrates from the same batch. Flexible substrates can be arranged in different sizes. Inductor circuits can be configured with different parameters, such as width. The electrodes of the inductor circuits are exposed for subsequent soldering of leads to extract the inductance signal.

[0071] The etched apertures penetrate both the protective layer and the flexible substrate, creating the aperture structure in a single fabrication process. This avoids inconsistencies in aperture parameters during subsequent processing, ensuring the uniformity of the aperture structure. The protective layer covers the area where the inductive circuitry is located, isolating it from external interference such as water and dust. This enhances the sensor's durability.

[0072] In summary, this invention provides an inductive flexible strain sensor with a slot array and its fabrication method. When an external deformation stimulus causes the flexible substrate of the sensor to deform, the slot array structure is stretched and deformed. Due to the presence of the slot array, the substrate material transforms in-plane stretching into out-of-plane bending, significantly increasing the tensile strength of the structure and expanding its detectable strain range. The inductive circuits located around the slot array experience changes in spacing due to substrate deformation, leading to changes in the circuit's self-inductance. By detecting the degree of change in the circuit's self-inductance, the magnitude of the strain is determined. Compared to traditional strain detection methods that add resistors to a flexible substrate and rely on structural deformation to change resistance, the inductive detection method converts changes in distance between the two sides of the slot structure into changes in circuit inductance, resulting in higher sensitivity. The combination of the slot array and the inductive detection circuit gives the flexible sensor higher sensitivity and a wider detection range.

[0073] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. An inductive flexible strain sensor with a slotted array, characterized in that, include: Flexible substrate; A seam array structure, comprising multiple staggered through seam structures arranged on the flexible substrate, wherein the seam structure is arranged as a horizontal or vertical extension of a basic staggered seam unit structure, wherein the basic staggered seam unit structure is arranged as follows: three seams a, b, and c are arranged parallel to the x-axis, the center positions of seams a and b are equidistant from the x-axis, seam c is spaced apart from seams a and b in the y-direction, the midpoint of the line connecting the adjacent tips of seams a and b is connected to the center of seam c, the line is perpendicular to the x-axis, and the three seams are staggered. An inductor circuit is bent and disposed on the flexible substrate, avoiding the slot array structure, so that the inductor circuit passes through and surrounds the slot array structure. When the substrate is stretched, the inductor circuit deforms with the substrate. A protective layer that covers and protects the area where the inductor circuit is located.

2. The inductive flexible strain sensor with slotted array according to claim 1, characterized in that, The slit tips of the slit array structure are set to be circular, and the diameter of the circle is greater than or equal to the width of the slit.

3. The inductive flexible strain sensor with slotted array according to claim 1, characterized in that, The inductor circuits arranged on both sides of the slit structure are arranged in a serpentine or loop-shaped manner.

4. The inductive flexible strain sensor with slotted array according to claim 1, characterized in that, The protective layer is made of a flexible material.

5. The inductive flexible strain sensor with slotted array according to claim 1, characterized in that, The flexible substrate is a bendable substrate.

6. The inductive flexible strain sensor with slotted array according to claim 1, characterized in that, The boundary shape of the flexible substrate is rectangular, convex, or concave.

7. The inductive flexible strain sensor with slotted array according to claim 1, characterized in that, The bending angles of the inductor circuit are: 90-degree right angles, arc-shaped corners, or polygonal corners.

8. The inductive flexible strain sensor with slotted array according to claim 1, characterized in that, The flexible substrate is prepared from PDMS material, polyimide film, or paper.

9. A method for fabricating an inductive flexible strain sensor with a slotted array as described in any one of claims 1-8, characterized in that, Including the following steps: Flexible substrate fabrication steps: A flexible substrate film is prepared on a planar substrate. The thickness of the substrate film is controlled according to the preparation process parameters to form a flexible substrate. Inductor circuit fabrication steps: The designed metal circuit is fabricated on a flexible substrate. The metal circuit includes two parts: inductor circuit and metal contacts. Protective layer fabrication steps: A flexible protective layer is fabricated above the inductor circuit, covering the inductor circuit portion and exposing the metal contact portion; Slot array structure etching steps: A slot array structure is etched on a flexible substrate on which the inductor circuit has been fabricated. The slots of the slot array structure penetrate the protective layer and the flexible substrate layer. Sensor fabrication steps: The flexible substrate film and metal circuit on the planar substrate are diced and sliced. The sliced ​​sensor is then peeled off from the planar substrate, and the fabrication is complete.

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