Flexible pressure sensor and its fabrication method

Abstract

This invention provides a flexible pressure sensor and its fabrication method. The fabrication method includes: forming a pressure sensing unit with a preset pattern on the surface of an adhesive layer using a pressure sensing substrate; transferring the pressure sensing unit from the surface of the adhesive layer to the surface of a conduit; forming a stretchable wire on the surface of the conduit using a conductive filler, and electrically connecting the stretchable wire to the pressure sensing unit to obtain a flexible pressure sensor; wherein the radius of the conduit is 0.25mm-0.80mm. This fabrication method can integrate a pressure sensing unit on the surface of a small conduit through curved surface transfer. The resulting flexible pressure sensor has good conformality with the conduit, a robust structure, and therefore high signal detection accuracy.

Description

Technical Field

[0001] This invention relates to the field of flexible electronics technology, and in particular to a flexible pressure sensor and its fabrication method. Background Technology

[0002] Invasive arterial blood pressure monitoring is a method of directly measuring blood pressure after arterial puncture and catheterization. During measurement, a catheter with a pressure sensor is inserted into the blood vessel. It can reflect the blood pressure changes in each cardiac cycle and achieve deep blood pressure monitoring. Its advantages are that the measurement results are more reliable for patients with vasospasm, shock, or cardiopulmonary bypass, and it can avoid invasive surgery with large incisions.

[0003] Because intravascular catheters are small in diameter, while existing catheter sensors are large and made of rigid materials, integrating pressure sensors onto catheters is difficult, and the sensing units are prone to failure on the catheter surface. Furthermore, the catheter undergoes significant deformation after being inserted into the blood vessel, and the flexible pressure sensor will also deform significantly, affecting the accuracy of the detected pressure signal. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a flexible pressure sensor and its preparation method in light of the above-mentioned existing technology. The preparation method can realize the preparation of a flexible pressure sensor on the surface of a small diameter conduit, and the resulting flexible pressure sensor has a robust structure and high measurement signal accuracy.

[0005] To achieve the above objectives, according to one aspect of the present invention, a method for fabricating a flexible pressure sensor is provided, the method comprising the following steps:

[0006] Provides an adhesive layer and a pressure-sensing substrate;

[0007] Using the pressure sensing substrate as raw material, a pressure sensing unit with a preset pattern is formed on the surface of the adhesive layer;

[0008] Provide a conduit for transferring the pressure sensing unit from the surface of the adhesive layer to the surface of the conduit; and

[0009] A conductive filler is provided, and the conductive filler is used to form a stretchable wire on the surface of the conduit. The stretchable wire is electrically connected to the pressure sensing unit to obtain the flexible pressure sensor.

[0010] The radius of the catheter is 0.25mm-0.80mm.

[0011] In one embodiment, the pressure sensing unit is arranged in a serpentine pattern, and the stretching / compression range of the pressure sensing unit is 20%-50%.

[0012] And / or, the extendable conductor is arranged in a serpentine pattern, and the stretching / compression range of the extendable conductor is 20%-50%.

[0013] In one embodiment, the step of forming a pressure sensing unit with a preset pattern on the surface of the adhesive layer using the pressure sensing substrate as a raw material includes:

[0014] The pressure sensing substrate is adhered to the surface of the adhesive layer;

[0015] The pressure sensing substrate is cut into a preset pattern area and a non-preset pattern area using a laser.

[0016] The pressure sensing substrate in the non-preset pattern area is peeled off from the surface of the adhesive layer, and the pressure sensing unit with the preset pattern is obtained on the surface of the adhesive layer.

[0017] In one embodiment, the material of the adhesive layer includes at least one of heat-release tape and water-soluble tape;

[0018] And / or, the pressure sensing substrate is a pressure film material, and the pressure film material includes at least one of polyvinylidene fluoride and copolymers of polyvinylidene fluoride.

[0019] In one embodiment, the step of forming a stretchable wire on the surface of the conduit with the conductive filler includes:

[0020] The surface of the catheter is modified.

[0021] The mold is prepared by 3D printing, and the surface of the mold has hollow areas.

[0022] The mold is placed on the conduit, and the hollowed-out area is positioned opposite to the surface of the conduit;

[0023] The conductive filler is deposited in the hollowed-out area, and the extendable wire is formed on the surface of the conduit.

[0024] In one embodiment, the number of the extendable wires is set to two, and the two extendable wires are respectively connected to the upper surface and the lower surface of the pressure sensing unit.

[0025] In one embodiment, the preparation method further includes: forming a stretchable wire on the surface of the conduit with the conductive filler, and before obtaining the flexible pressure sensor.

[0026] A flexible encapsulation layer is provided to cover the stretchable conductor.

[0027] In one embodiment, the material of the flexible encapsulation layer includes at least one of polyimide, polydimethylsiloxane, and hydrogel, and the thickness of the flexible encapsulation layer is 5μm-50μm.

[0028] In one embodiment, the number of pressure sensing units is set to two or more, and the two or more pressure sensing units are arranged in an array on the surface of the conduit along the length of the conduit, and the two or more pressure sensing units are electrically connected to each other through the extendable wire.

[0029] According to another aspect of the present invention, a flexible pressure sensor is provided, the flexible pressure sensor being prepared by the method described in any one of the preceding claims, the flexible pressure sensor comprising the conduit, the pressure sensing unit, and the extendable wire, the pressure sensing unit and the extendable wire being disposed on the surface of the conduit and respectively arranged in a serpentine meandering manner, and the extendable wire being electrically connected to the pressure sensing unit.

[0030] Compared with the prior art, the beneficial effects of the method for preparing the flexible pressure sensor of the present invention are as follows:

[0031] First, the preparation method of the present invention can integrate a pressure sensing unit on the surface of a small catheter by means of curved surface transfer. The pressure sensing unit with a fine preset pattern can be tightly wrapped on the surface of the catheter using an adhesive layer. After curved surface transfer, the pressure sensing unit is peeled off from the surface of the adhesive layer, so that the pressure sensing unit can be firmly adhered to the surface of the catheter. The preparation method is simple and reliable, and the flexible pressure sensor prepared has a good conformity with the catheter and a robust structure, thus resulting in a high accuracy of signal detection.

[0032] Secondly, by preparing a serpentine pressure sensing unit and an extendable wire, the present invention enables the pressure sensing unit to have high ductility. The pressure sensing unit and the extendable wire can deform with the bending and deformation of the conduit, and this deformation can offset the tensile force transmitted by the conduit due to deformation, effectively preventing the pressure sensing unit and the extendable wire from debonding or breaking due to deformation. Furthermore, the connection between the pressure sensing unit and the extendable wire and the conduit is more stable and reliable, further ensuring the accuracy of signal detection.

[0033] Furthermore, the flexible pressure sensor of the present invention has a small size, high tensile / compression resistance and high flexibility, and is particularly suitable for sensing or sensing applications that require a certain degree of bending and stretching. It can be widely used in fields such as flexible pressure sensing.

[0034] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0035] Figure 1 A schematic diagram illustrating a method for fabricating a flexible pressure sensor according to one embodiment of the present invention;

[0036] Figure 2(a) is a schematic diagram of the structure of a pressure sensing unit provided in one embodiment of the present invention;

[0037] Figure 2(b) is a schematic diagram of the structure of a pressure sensing unit provided in one embodiment of the present invention;

[0038] Figure 2(c) is a schematic diagram of the structure of a pressure sensing unit provided in one embodiment of the present invention;

[0039] Figure 2(d) is a schematic diagram of the structure of a pressure sensing unit provided in one embodiment of the present invention;

[0040] Figure 2(e) is a schematic diagram of the structure of a pressure sensing unit provided in one embodiment of the present invention;

[0041] Figure 3(a) is a schematic diagram of the structure of a pressure sensing unit provided in one embodiment of the present invention;

[0042] Figure 3(b) shows the piezoelectric signal of the pressure sensing unit in Figure 3(a) under dynamic pressure;

[0043] Figure 3(c) shows the relationship between the peak value of the piezoelectric signal of the pressure sensing unit in Figure 3(a) and the pressure;

[0044] Figure 4 for Figure 1 A schematic diagram of the structure of the flexible pressure sensor prepared by the method shown.

[0045] Figure 5 A schematic diagram illustrating a method for fabricating a flexible pressure sensor according to one embodiment of the present invention;

[0046] Figure 6 for Figure 5 The diagram shows the structure of a flexible pressure sensor prepared by the method shown. Detailed Implementation

[0047] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0049] 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 the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0050] According to one aspect of the present invention, a method for manufacturing a flexible pressure sensor 100 is provided. See also... Figure 1 As shown, Figure 1 This is a schematic diagram illustrating the fabrication method of a flexible pressure sensor 100 according to one embodiment of the present invention.

[0051] The preparation method includes the following steps:

[0052] S1: Provides an adhesive layer and a pressure-sensing substrate;

[0053] S2: Using the pressure sensing substrate as raw material, a pressure sensing unit 120 with a preset pattern is formed on the surface of the adhesive layer;

[0054] S3: Provide a conduit 110 to transfer the pressure sensing unit 120 from the surface of the adhesive layer to the surface of the conduit 110; and

[0055] S4: Provide conductive filler, form a stretchable wire 130 on the surface of the conduit 110 with the conductive filler, and electrically connect the stretchable wire 130 to the pressure sensing unit 120 to obtain the flexible pressure sensor 100.

[0056] The radius of the catheter 110 is 0.25mm-0.80mm.

[0057] Existing flexible pressure sensing units can be used on planar substrates. Planar substrates, due to their flat surfaces, facilitate the integration of island-bridge-shaped functional units. Furthermore, the bending and deformation ranges of planar substrates are relatively small, resulting in a relatively robust structure for flexible pressure sensors formed on planar substrates, thus enabling stable use. However, for smaller diameter conduits, on the one hand, the small diameter of the conduit itself limits the maximum size of the sensing unit, and its surface has a large radius of curvature and a high degree of bending, making it difficult to integrate island-bridge-shaped sensing units on its surface. On the other hand, conduits are prone to significant bending and deformation during use. Even if the sensing unit can be integrated onto the surface of the conduit, it will deform with the bending and deformation of the conduit, making the sensing unit prone to detachment or breakage on the conduit surface, leading to inaccurate sensing signals or even loss of sensing function.

[0058] The flexible pressure sensor fabrication method of the present invention can integrate a pressure sensing unit on the surface of a small conduit by means of curved surface transfer printing. The pressure sensing unit with a finely pre-set pattern can be tightly wrapped on the surface of the conduit using an adhesive layer. After curved surface transfer printing, the pressure sensing unit can be peeled off from the surface of the adhesive layer, so that the pressure sensing unit can be firmly adhered to the surface of the conduit. This fabrication method is simple and reliable, and the resulting flexible pressure sensing unit has a good conformity with the conduit and a robust structure, thus resulting in a high accuracy of signal detection.

[0059] Taking the bending deformation of a conduit as an example, the degree of conformity between the pressure sensing unit and the conduit surface is directly related to the bending stiffness of the pressure sensing unit. The smaller the bending stiffness of the pressure sensing unit, the better the conformity. The bending stiffness of the pressure sensing unit depends on its material modulus and dimensions. For the pressure sensing unit structure on the conduit surface, its bending stiffness is proportional to the material modulus and the cube of the thickness. The material modulus and thickness used in the pressure sensing unit of this invention are much smaller than those of traditional pressure sensing units. This results in a small bending stiffness, good conformity with the conduit, and a robust structure, thus leading to high signal detection accuracy.

[0060] Furthermore, by preparing a serpentine pressure sensing unit and an extendable wire, the present invention enables the pressure sensing unit to have high ductility. The pressure sensing unit and the extendable wire can deform with the bending and deformation of the conduit, and this deformation can offset the tensile force transmitted by the conduit due to deformation. This effectively prevents the pressure sensing unit and the extendable wire from debonding or breaking due to deformation. Moreover, the connection between the pressure sensing unit and the extendable wire and the conduit is more stable and reliable, further ensuring the accuracy of signal detection.

[0061] It is understood that in other embodiments, Figure 1The order of steps S3 and S4 in the preparation method can be changed. That is, during the preparation process, the stretchable wire 130 is formed first and then the surface of the pressure sensing unit 120 self-adhesive layer is transferred to the surface of the conduit 110, which is also within the protection scope of the present invention.

[0062] Please refer to Figure 2(a), which is a schematic diagram of the structure of a pressure sensing unit 120 provided in one embodiment of the present invention. The pressure sensing unit 120 extends in a serpentine pattern on the surface of the conduit 110. This serpentine pattern can improve the extensibility of the pressure sensing unit 120 itself, and the thickness of the pressure sensing unit 120 is ≤50μm. It is understood that, as shown in Figure 2(b), in other embodiments, the pressure sensing unit 120 may also be two sets of serpentine lines intersecting each other, with an included angle of 90°; as shown in Figure 2(c), the pressure sensing unit 120 may also be three sets of serpentine lines intersecting each other, with an included angle of 120°; as shown in Figures 2(d) and 2(e), the pressure sensing unit 120 may also be multiple sets of rings connected in series. This is only a limited example of the pressure sensing unit 120. The pressure sensing unit 120 disposed on the surface of the conduit 110 can be in any serpentine pattern, all of which are within the protection scope of the present invention.

[0063] In one embodiment, the catheter 110 can be bent along its length to adapt to the shape of the blood vessel when it is inserted deep inside the vessel. Preferably, the radius of the catheter 110 is 0.35mm-0.38mm to better adapt to the usage scenarios inside the blood vessel.

[0064] It should be understood that the flexible pressure sensor 100 provided by the present invention is not only suitable for pressure sensing or sensing inside blood vessels, but also suitable for pressure sensing or sensing in other application scenarios that require a certain degree of bending and stretching. It can be widely used in various flexible pressure sensing or biomedical applications.

[0065] Furthermore, the bending radius of the conduit 110 is greater than or equal to 3 mm; the pressure sensing unit 120 and the extendable wire 130 can bend and deform as the conduit 110 bends. When bending and torsional deformation occurs, the pressure sensing unit 120 and the extendable wire 130 also possess stretchability and compressibility, with the stretching / compression range of the pressure sensing unit 120 and the extendable wire 130 being 20%-50%.

[0066] Specifically, step S2 includes:

[0067] S2.1: Adhere the pressure sensing substrate to the surface of the adhesive layer;

[0068] S2.2: The pressure sensing substrate is cut into a preset pattern area and a non-preset pattern area using a laser;

[0069] S2.3: Peel the pressure sensing substrate in the non-preset pattern area from the surface of the adhesive layer to obtain the pressure sensing unit 120 with the preset pattern on the surface of the adhesive layer.

[0070] In one embodiment, the material of the adhesive layer includes at least one of heat-release tape and water-soluble tape.

[0071] The pressure sensing substrate is a pressure film material, and the pressure film material includes at least one of polyvinylidene fluoride (PVDF) and a copolymer of polyvinylidene fluoride (PVDF). Preferably, the copolymer of polyvinylidene fluoride (PVDF) can be a polyvinylidene fluoride copolymer (PVDF-TrFE).

[0072] Referring to Figure 3(a), a schematic diagram of the pressure sensing unit 120 provided in one embodiment of the present invention is shown, illustrating annular and circular pressure sensing units 120 fabricated using PVDF piezoelectric thin films. Further, referring to Figures 3(b) and 3(c), Figure 3(b) shows the piezoelectric signal of the pressure sensing unit 120 in Figure 3(a) under dynamic pressure, and Figure 3(c) shows the relationship between the peak value of the piezoelectric signal of the pressure sensing unit 120 in Figure 3(a) and the pressure. As can be seen from Figures 3(b) and (c), the pressure sensing unit 120 has reliable pressure sensing or induction functions.

[0073] In step S2.2, a pressure sensing unit 120 with a fine preset pattern can be obtained by laser cutting. It is understood that in other embodiments, the method of preparing the pressure sensing unit 120 with a fine preset pattern is not limited to laser cutting. Here, only a preferred and easy-to-implement embodiment is exemplified.

[0074] Furthermore, in one embodiment, step S2 further includes:

[0075] After step S2.2 and before step S2.3, the adhesive layer is heat-treated to reduce the adhesion between the adhesive layer and the pressure-sensing substrate. It is understood that in other embodiments, other methods, such as organic solvent treatment or light treatment, can also be used to reduce the adhesion between the adhesive layer and the pressure-sensing substrate, and this invention is not limited thereto.

[0076] In one embodiment, step S4 specifically includes:

[0077] S4.1: Modify the surface of the catheter 110;

[0078] S4.2: A mold is prepared by 3D printing, and the surface of the mold has a hollow area;

[0079] S4.3: The mold is placed on the conduit, and the hollowed-out area is positioned opposite to the surface of the conduit;

[0080] S4.4: Deposit the conductive filler in the hollowed-out area and form the extendable wire 130 on the surface of the conduit 110.

[0081] In one embodiment, the modification process in step S4.1 includes, but is not limited to, laser etching, and the surface of the conduit 110 may be pre-cleaned with acetone, ethanol, or deionized water.

[0082] In one embodiment, the deposition method in step S4.4 includes, but is not limited to, magnetron sputtering.

[0083] For the reasons mentioned above, it is difficult to fabricate wires with fine structures on curved and non-flat surfaces. This invention utilizes a mold and magnetron sputtering to jointly fabricate and integrate the stretchable wire 130 on the surface of the conduit 110. Specifically, a mold with a wire-shaped cutout is first fabricated using 3D printing technology. Then, the wire mold is placed outside the conduit 110, where metal is to be deposited, in the magnetron sputtering chamber, ensuring that metal sputtering occurs only in the cutout area of ​​the mold, thereby achieving the fabrication of the finely patterned stretchable wire 130. This fabrication method not only enables metal deposition in specific areas of curved surfaces but is also suitable for metal deposition on small-diameter conduits 110.

[0084] In one embodiment, the stretchable wire 130 prepared in step S4.4 includes a first metal layer and a second metal layer, the first metal layer being disposed on the surface of the conduit 110, and the second metal layer being disposed on the first metal layer.

[0085] Preferably, the first metal layer can be a chromium metal layer to increase the adhesion between the second metal layer and the surface of the conduit 110, and the second metal layer can be a gold (Au) metal layer. The thickness of the first metal layer can be 5nm-20nm, and the thickness of the second metal layer can be 80nm-300nm.

[0086] In one embodiment, the number of the extendable wires 130 is set to two, and the two extendable wires 130 are electrically connected to the upper surface and the lower surface of the flexible pressure sensor 100, respectively.

[0087] Accordingly, in fabricating the flexible pressure sensor 100, the surface of the conduit 110 is first modified to make the adhesion between the pressure sensing unit 120 and the surface of the conduit 110 more compact, and the deposition of the extendable wire 130 on the surface of the conduit 110 more reliable. Then, an extendable wire 130 is first fabricated using the above deposition process, and then the pressure sensing unit 120 is transferred to the surface of the conduit 110 by curved surface transfer printing. The pressure sensing unit 120 is aligned and covered with one end of the extendable wire 130, so that the lower surface of the pressure sensing unit 120 is electrically connected to one end of the extendable wire. Next, another extendable wire 130 can be fabricated using the above deposition process, and one end of the extendable wire 130 is deposited on the upper surface of the pressure sensing unit 120, so that the two form an electrical circuit.

[0088] See Figure 4 The diagram shows the structure of the flexible pressure sensor 100 obtained by the above preparation method. The flexible pressure sensor 100 includes the conduit 110, the pressure sensing unit 120, and the extendable wire 130. The pressure sensing unit 120 and the extendable wire 130 are both disposed on the surface of the conduit 110 and are respectively arranged in a serpentine meandering shape. The extendable wire 130 is electrically connected to the pressure sensing unit 120.

[0089] See Figure 5 As shown, in one embodiment, the preparation method further includes: after forming a stretchable wire 130 on the surface of the conduit 110 with the conductive filler, and before obtaining the flexible pressure sensor 100,

[0090] S5: Provide a flexible encapsulation layer 140 so that the flexible encapsulation layer 140 covers the stretchable wire 130;

[0091] The flexible encapsulation layer 140 covers the extendable wire 130 and serves as insulation. It is worth noting that the pressure sensing unit 120 does not need to be covered by the flexible encapsulation layer 140.

[0092] The flexible encapsulation layer 140 is made of at least one of polyimide (PI), polydimethylsiloxane (PDMS), and hydrogel, and the thickness of the flexible encapsulation layer 140 is 5μm-50μm.

[0093] Preferably, the thickness of the flexible encapsulation layer 140 is 5 μm.

[0094] See Figure 6The diagram shows the structure of the flexible pressure sensor 100 obtained by the above preparation method. The flexible pressure sensor 100 includes the conduit 110, the pressure sensing unit 120, the extendable wire 130, and the flexible encapsulation layer 140. The pressure sensing unit 120 and the extendable wire 130 are both disposed on the surface of the conduit 110 and are arranged in a serpentine pattern. The extendable wire 130 is electrically connected to the pressure sensing unit 120. The flexible encapsulation layer 140 covers the two extendable wires 130, providing insulation and ensuring safety and reliability during use.

[0095] In one embodiment, the fabrication method involves preparing multiple pressure sensing units 120 and extendable wires 130 at different locations on the surface of the catheter 110 to achieve array-based integration of pressure sensing, thereby enabling multi-point measurement. The multiple pressure sensing units 120 can form an array module to obtain richer strain information. This configuration results in a flexible pressure sensor 100 with an array sensing structure, capable of simultaneously acquiring spatial distribution information of pressure signals from multiple locations within the blood vessel. The flexibility of this array sensing structure allows for closer and deeper contact between the flexible pressure sensor 100 and the blood vessel wall.

[0096] Accordingly, the number of pressure sensing units 120 is set to two or more, and the two or more pressure sensing units 120 are arranged in an array along the length of the conduit 110 on the surface of the conduit 110. Each pressure sensing unit 120 and the extendable wire 130 constitute a sensing module, and the multiple sensing modules are independent of each other and can sense pressure signals separately.

[0097] The array-type flexible pressure sensor provided by this invention integrates multiple pressure sensing units through meandering, extendable wires. When the catheter is inserted into the blood vessel, the catheter will adapt to the shape of the blood vessel and bend, stretch, or compress. At this time, the meandering, extendable wires will also deform with the deformation of the catheter. The catheter and the extendable wires will not exert a pulling force on the pressure sensing units. The array-type pressure sensing units can be firmly attached to the surface of the catheter without detaching, thereby making the array-type flexible pressure sensor highly ductile.

[0098] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0099] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for fabricating a flexible pressure sensor, characterized in that, The preparation method includes the following steps: Provides an adhesive layer and a pressure-sensing substrate; Using the pressure sensing substrate as raw material, a pressure sensing unit with a preset pattern is formed on the surface of the adhesive layer; Provide a conduit for transferring the pressure sensing unit from the surface of the adhesive layer to the surface of the conduit; and A conductive filler is provided, and the conductive filler is used to form a stretchable wire on the surface of the conduit. The stretchable wire is electrically connected to the pressure sensing unit to obtain the flexible pressure sensor. The radius of the conduit is 0.25mm-0.80mm, the pressure sensing unit is arranged in a serpentine pattern, and the extendable wire is also arranged in a serpentine pattern. The step of forming a pressure sensing unit with a preset pattern on the surface of the adhesive layer using the pressure sensing substrate as raw material includes: The pressure sensing substrate is adhered to the surface of the adhesive layer; The pressure sensing substrate is cut into a preset pattern area and a non-preset pattern area using a laser. The pressure sensing substrate in the non-preset pattern area is peeled off from the surface of the adhesive layer, and the pressure sensing unit with the preset pattern is obtained on the surface of the adhesive layer. The step of forming a stretchable wire on the surface of the conduit with the conductive filler includes: The surface of the catheter is modified. The mold is prepared by 3D printing, and the surface of the mold has hollow areas. The mold is placed on the conduit, and the hollowed-out area is positioned opposite to the surface of the conduit; The conductive filler is deposited in the hollowed-out area, and the extendable wire is formed on the surface of the conduit.

2. The method for fabricating a flexible pressure sensor according to claim 1, characterized in that, The stretching / compression range of the pressure sensing unit is 20%-50%; And / or, the stretchable conductor has a stretch / compression range of 20%-50%.

3. The method for fabricating a flexible pressure sensor according to claim 1, characterized in that, The adhesive layer material includes at least one of heat-release tape and water-soluble tape; And / or, the pressure sensing substrate is a pressure film material, and the pressure film material includes at least one of polyvinylidene fluoride and copolymers of polyvinylidene fluoride.

4. The method for fabricating a flexible pressure sensor according to claim 1, characterized in that, The number of the extendable wires is set to two, and the two extendable wires are respectively connected to the upper surface and the lower surface of the pressure sensing unit.

5. The method for fabricating a flexible pressure sensor according to claim 1, characterized in that, The preparation method further includes: forming a stretchable wire on the surface of the conduit with the conductive filler, and before obtaining the flexible pressure sensor. A flexible encapsulation layer is provided to cover the stretchable conductor.

6. The method for fabricating a flexible pressure sensor according to claim 5, characterized in that, The flexible encapsulation layer is made of at least one of polyimide, polydimethylsiloxane, and hydrogel, and the thickness of the flexible encapsulation layer is 5μm-50μm.

7. The method for fabricating a flexible pressure sensor according to claim 1, characterized in that, The number of pressure sensing units is set to two or more, and the two or more pressure sensing units are arranged in an array on the surface of the conduit along the length of the conduit. The two or more pressure sensing units are electrically connected to each other through the extendable wire.

8. A flexible pressure sensor, characterized in that, The flexible pressure sensor is prepared by the method according to any one of claims 1-7. The flexible pressure sensor includes the conduit, the pressure sensing unit and the extendable wire. The pressure sensing unit and the extendable wire are both disposed on the surface of the conduit and are respectively arranged in a serpentine meandering shape. The extendable wire is electrically connected to the pressure sensing unit.

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