Single-substrate printing type flexible pressure sensor

Abstract

The utility model relates to the technical field of flexible sensors, in particular to a single-substrate printing type flexible pressure sensor. The single-substrate printing type flexible pressure sensor comprises a PET base body and an interdigital device arranged on the PET base body, the interdigital device comprises an interdigital electrode and a foaming conductive layer, the interdigital electrode is printed on the PET base body and electrically connected with the foaming conductive layer, the foaming conductive layer is provided with a plurality of first aperture openings, a plurality of closed holes and a plurality of second aperture openings, and the first aperture openings, the closed holes and the second aperture openings are formed in the PET base body. And the aperture of the first aperture opening is greater than that of the second aperture opening. The foaming conductive layer is provided with a plurality of first aperture open pores, a plurality of closed pores and a plurality of second aperture open pores for balancing positive and negative pressure effects, so that the single-substrate printed flexible pressure sensor has the advantages of controllable positive / negative pressure resistance effects and adjustable longitudinal conductive particle concentration.

Description

Technical Field

[0001] The utility model relates to the technical field of flexible sensors, in particular to a single-substrate printed flexible pressure sensor. Background Art

[0002] A flexible pressure sensor is a sensor that can measure and detect the pressure exerted by an object or medium and has the characteristics of flexibility and variability.

[0003] In related technologies, flexible pressure sensors include, but are not limited to, the following four types. The first involves 3D printing a rectangular force-sensitive, separate sensor using flexible silicone rubber as the matrix, carbon nanotubes as the conductive filler, and expanded microspheres as the multifunctional reinforcing filler. The resistance of each sensor decreases as pressure increases, exhibiting a negative piezoresistive effect. The second involves using PDMS silicone rubber as the flexible base material and nanocarbon black as the conductive doping material. A single-base printed paste is prepared through prolonged stirring and grinding. The resistance of each sensor increases as pressure increases, exhibiting a positive piezoresistive effect, with the maximum resistance change ratio reaching 17.5 times. The third involves using acrylic acid as an additive to study its effect on silver nanowire transparent conductive films. Acrylic resin solutions can effectively enhance the adhesion of silver nanowire transparent conductive films. However, acrylic resin is insulating, and excessive addition increases the contact resistance of the silver nanowires, reducing the conductivity of the silver nanowire network. Fourthly, GO (graphene oxide) aqueous dispersion is used as the precursor of the conductive filler, and Vitamin C (vitamin C) simultaneously reduces GO to rGO (reduced graphene oxide). By changing the amount of GO aqueous dispersion and the type and concentration of the emulsifier, the pore size of the composite material and the distribution of the conductive filler in the force-sensitive layer are regulated. The flexible pressure sensor prepared by this method exhibits a negative piezoresistive effect, and the preparation process is extremely complex.

[0004] For the four types of flexible pressure sensors mentioned above, the positive and negative piezoresistive effects of devices made of the same material or process are uncontrollable. The piezoresistive effect of the same material and process is single, and the concentration of longitudinal conductive particles in the flexible pressure sensor, i.e., the resistance gradient, cannot be adjusted. The fabrication process is complex, and the substrate adhesion is poor. Therefore, there is still considerable room for development and improvement in flexible pressure sensors. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a single-substrate printed flexible pressure sensor with good adhesion, controllable positive / negative piezoresistive effect, and adjustable longitudinal conductive particle concentration (resistance gradient).

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A single-substrate printed flexible pressure sensor, comprising:

[0008] A PET substrate and an interdigital device disposed on the PET substrate, the interdigital device comprising interdigital electrodes and a foamed conductive layer. The interdigital electrodes are printed on the PET substrate and electrically connected to the foamed conductive layer. The foamed conductive layer comprises a plurality of first-diameter openings, a plurality of closed pores, and a plurality of second-diameter openings, wherein the first-diameter openings have a larger aperture than the second-diameter openings. When the foamed conductive layer is subjected to low pressure, the loose and easily deformable first-diameter openings deform first, exhibiting a negative piezoresistive effect. When the foamed conductive layer is subjected to high pressure, the closed pores or the second-diameter openings deform, causing a sudden increase in resistance, exhibiting a positive piezoresistive effect. This achieves controllable positive / negative piezoresistive effects, thus enabling a single-substrate printed flexible pressure sensor with adjustable longitudinal conductive particle concentration (resistance gradient).

[0009] Optionally, the PET substrate is a PET film to ensure the flexibility of the single-substrate printed flexible pressure sensor.

[0010] Optionally, the aperture of the first aperture opening is 30-200 μm to ensure that the negative piezoresistive effect of the foamed conductive layer is controllable.

[0011] Optionally, the pore diameter of the closed cells is 30-200 μm to ensure that the positive piezoresistive effect of the foamed conductive layer is controllable.

[0012] Optionally, the aperture of the second aperture opening is 5-50 μm to ensure that the positive piezoresistive effect of the foamed conductive layer is controllable.

[0013] In summary, the present invention has at least the following beneficial technical effects:

[0014] 1. The single-substrate printed flexible pressure sensor includes multiple first-aperture openings, multiple closed pores, and multiple second-aperture openings. When the single-substrate printed flexible pressure sensor is subjected to small pressure, the loose and easily deformed first-aperture openings deform first, exhibiting a negative piezoresistive effect. When the single-substrate printed flexible pressure sensor is subjected to large pressure, the closed pores or second-aperture openings deform, and the resistance suddenly increases, exhibiting a positive piezoresistive effect. Therefore, the flexible pressure sensor has the characteristics of controllable positive / negative piezoresistive effect and adjustable longitudinal conductive particle concentration (resistance gradient). BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of a single-substrate printed flexible pressure sensor in an embodiment of the present invention.

[0016] Figure 2 1 is a side view of a single-substrate printed flexible pressure sensor according to an embodiment of the present invention.

[0017] Figure 3 This is the relationship diagram between pore state and piezoresistive effect.

[0018] Figure 4 Schematic diagram of the foamed conductive layer.

[0019] Explanation of the accompanying symbols: 1. PET substrate; 2. interdigitated electrodes; 3. foamed conductive layer. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0021] The terms used in the following embodiments of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, the singular expressions "a", "an", "said", "above", "the", and "this" are intended to include plural expressions as well, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used in the present invention refers to and includes any or all possible combinations of one or more of the listed items. The term "exemplary" means "serving as an example, embodiment, or illustration", and any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments. The terms "first" and "second" are used for descriptive purposes only and should not be understood to imply or suggest relative importance or to implicitly indicate the number of the indicated technical features. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, unless otherwise specified, "multiple" means two or more.

[0022] This embodiment provides a single-substrate printed flexible pressure sensor.

[0023] refer to Figure 1 and Figure 2 A single-substrate printed flexible pressure sensor comprises a PET substrate 1 and an interdigital device. To prepare the single-substrate printed flexible pressure sensor, multiple interdigital devices are arranged on the PET substrate 1. After preparation, the PET substrate 1 is cut to produce multiple individual single-substrate printed flexible pressure sensors. The PET substrate 1 is made of PET film to ensure flexibility.

[0024] The interdigital device includes interdigital electrodes 2 and a foamed conductive layer 3. The interdigital electrodes 2 are printed on a PET substrate 1, and the foamed conductive layer 3 is electrically connected to the interdigital electrodes 2, and the foamed conductive layer 3 is located on the PET substrate 1. There are two interdigital electrodes 2 in an interdigital device, one of which is the input end of the electrical signal and the other is the output end of the electrical signal. The foamed conductive layer 3 has pores, which include a plurality of first aperture openings, a plurality of closed pores, and a plurality of second aperture openings, wherein the pore diameter of the first aperture openings is larger than the pore diameter of the second aperture openings. The pore diameter of the first aperture openings is 30 to 200 μm, the pore diameter of the closed pores is 30 to 200 μm, and the pore diameter of the second aperture openings is 5 to 50 μm.

[0025] refer to Figure 3 and Figure 4 When the foamed conductive layer 3 is subjected to a small pressure, the first aperture openings with a loose structure and easy deformation are deformed first, showing a negative piezoresistive effect; when the foamed conductive layer 3 is subjected to a large pressure, the closed cells or the second aperture openings are deformed, and the resistance suddenly increases, showing a positive piezoresistive effect. Therefore, it has the characteristics of controllable positive / negative piezoresistive effect and adjustable longitudinal conductive particle concentration (resistance gradient).

[0026] This embodiment also provides an insole, comprising an upper insole layer, a lower insole layer, and the aforementioned single-substrate printed flexible pressure sensor. The single-substrate printed flexible pressure sensor is encapsulated between the upper and lower insole layers, and the edges of the upper and lower insole layers are stitched together. During insole production, the foamed conductive layer 3 can be synchronously calibrated using a press to determine the relationship between force and resistance. After stitching, a debugging interface can be brought out, and the insole can be placed in a shoe of the same size as the insole to collect a force cloud map of the sole of the foot. In addition, by adjusting the insole's response threshold to external force, three-dimensional information of different types of ground can also be collected.

[0027] The above embodiments are merely a detailed introduction to the technical solutions of the present invention. However, the description of the above embodiments is only intended to help understand the method and core concept of the present invention and should not be construed as limiting the present invention. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A single-substrate printed flexible pressure sensor, characterized in that: include: A PET substrate (1) and an interdigital device arranged on the PET substrate, the interdigital device comprising interdigital electrodes (2) and a foamed conductive layer (3), the interdigital electrodes (2) being printed on the PET substrate (1), the interdigital electrodes (2) being electrically connected to the foamed conductive layer (3), the foamed conductive layer (3) having a plurality of first aperture openings, a plurality of closed pores, and a plurality of second aperture openings, the aperture of the first aperture openings being larger than the aperture of the second aperture openings.

2. The single-substrate printed flexible pressure sensor according to claim 1, wherein: The PET substrate (1) is a PET film.

3. The single-substrate printed flexible pressure sensor according to claim 1, wherein: The aperture of the first aperture opening is 30 to 200 μm.

4. The single-substrate printed flexible pressure sensor according to claim 1, wherein: The pore diameter of the closed pores is 30 to 200 μm.

5. The single-substrate printed flexible pressure sensor according to claim 1, wherein: The second aperture opening has an aperture of 5 to 50 μm.

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