A flexible pressure sensor

Abstract

This invention discloses a flexible pressure sensor, comprising a flexible upper substrate layer, a flexible lower substrate layer, a mesh upper electrode, a mesh lower electrode, and a flexible piezoresistive material. The flexible upper and lower substrate layers are made of fabric material with an adhesive layer. The mesh upper electrode extends along a first direction, and the mesh lower electrode extends along a second direction, with the two electrodes intersecting to form multiple intersection points. The flexible piezoresistive material is disposed at the intersection points. When pressure is applied, the contact area of ​​the mesh electrodes through the piezoresistive material increases, resulting in a decrease in resistance at the intersection points, thus achieving pressure detection. This invention utilizes a fully flexible fiber material for construction, achieving large-area pressure detection with a multi-point array distribution. It has the advantages of simple structure and low cost; the sensor can be bent, folded, and crumpled without affecting its performance.

Description

Technical Field

[0001] This utility model relates to the field of sensor technology, and in particular to a flexible pressure sensor. Background Technology

[0002] With increasing attention paid to health monitoring and smart homes, sleep quality monitoring technology has gained widespread importance. Pressure sensors, as core components of sleep monitoring, can analyze physiological parameters such as sleep state, turning frequency, respiration, and heart rate by detecting the distribution and changes in pressure on the body in bed. Among existing pressure sensors, thin-film pressure sensors are particularly suitable for bed sleep monitoring.

[0003] However, thin-film pressure sensors are typically composed of multiple layers of plastic film stacks. This structure has significant technical drawbacks in bed applications: due to large localized deformation from pressure or folding, the plastic film stacks can suffer structural damage, leading to failure or a significant decrease in piezoresistive performance. Furthermore, existing thin-film pressure sensors mostly employ single-point or a few-point detection designs, making it impossible to achieve large-area multi-point array distribution detection. This results in higher manufacturing costs and poor material compatibility and environmental adaptability, making it difficult to meet the needs of flexible applications such as bed sleep monitoring. Utility Model Content

[0004] To overcome the shortcomings of the existing technology, this utility model provides a flexible pressure sensor that is bendable, foldable, and capable of multi-point detection.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] A flexible pressure sensor includes: a flexible upper substrate layer; a flexible lower substrate layer; a mesh upper electrode disposed on the flexible upper substrate layer and extending along a first direction; a mesh lower electrode disposed on the flexible lower substrate layer and extending along a second direction intersecting the first direction, such that the mesh upper electrode and the mesh lower electrode spatially intersect to form multiple intersection points; and a flexible piezoresistive material disposed at the intersection points between the mesh upper electrode and the mesh lower electrode. When pressure is applied to the intersection points, the contact area between the mesh upper electrode and the mesh lower electrode through the flexible piezoresistive material increases, resulting in a decrease in resistance at the intersection points, thereby achieving pressure detection at the intersection points.

[0007] Furthermore, the flexible upper substrate layer and / or flexible lower substrate layer are fabric-based materials with adhesive layers.

[0008] Furthermore, the mesh upper electrode and mesh lower electrode are composed of conductive tape, conductive cloth or conductive wire.

[0009] Furthermore, the conductive cloth or conductive wire is formed into a mesh structure by bonding, sewing or weaving.

[0010] Furthermore, the mesh shape of the upper and lower mesh electrodes is square, rhomboid, or triangular.

[0011] Furthermore, the flexible piezoresistive material is in the form of discrete dots or small patches at the intersection.

[0012] Furthermore, the flexible piezoresistive material is a continuous sheet that covers the mesh upper electrode or mesh lower electrode and is located at the plurality of intersections.

[0013] Furthermore, the flexible piezoresistive material is a piezoresistive fabric.

[0014] Furthermore, the piezoresistive fabric includes a flexible base fabric and conductive fillers dispersed in the flexible base fabric or coated on the surface of the flexible base fabric.

[0015] Furthermore, the conductive filler is a carbon-based material.

[0016] The beneficial effects of this utility model are:

[0017] This invention discloses a flexible pressure sensor, comprising a flexible upper substrate layer, a flexible lower substrate layer, a mesh upper electrode, a mesh lower electrode, and a flexible piezoresistive material. The flexible upper and lower substrate layers are made of a fabric-based material with an adhesive layer. The mesh upper electrode is arranged on the flexible upper substrate layer and extends along a first direction, while the mesh lower electrode is arranged on the flexible lower substrate layer and extends along a second direction intersecting the first direction, causing the mesh upper and lower electrodes to spatially intersect at multiple intersection points. The flexible piezoresistive material is disposed at these intersection points. When pressure is applied to the intersection points, the contact area between the mesh upper and lower electrodes through the flexible piezoresistive material increases, resulting in a decrease in resistance at the intersection points, thereby achieving pressure detection. The mesh electrode is composed of conductive tape, conductive cloth, or conductive wire, and the piezoresistive material is a piezoresistive fabric. This invention utilizes a fully flexible fiber material for construction, achieving large-area pressure detection with a multi-point array distribution. It has the advantages of simple structure and low cost; the sensor can be bent, folded, and crumpled without affecting its performance. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Figure 1 This is a schematic diagram of the disassembled structure of this utility model. Detailed Implementation

[0020] The following will clearly and completely describe the concept, specific structure, and technical effects of this utility model in conjunction with embodiments and accompanying drawings, so as to fully understand the purpose, features, and effects of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are all within the scope of protection of this utility model. Furthermore, all connections / linkages involved in the patent do not simply refer to direct contact between components, but rather to the ability to form a better connection structure by adding or reducing connecting accessories according to specific implementation conditions. The various technical features in this utility model can be combined interactively without contradicting each other.

[0021] This utility model provides a flexible pressure sensor constructed from flexible fiber material. Through the interlaced arrangement of mesh electrodes and the cooperation of piezoresistive material, it achieves large-area pressure detection with a multi-point array distribution. The sensor has a simple overall structure, low manufacturing cost, and excellent flexibility, allowing it to be bent, folded, and crumpled without affecting its performance. The sensor works by increasing the contact area between the mesh electrodes (a conductive structure arranged in a grid pattern, ensuring conductivity while maintaining flexibility and breathability) and the lower electrode through the piezoresistive material when pressure is applied. This leads to a decrease in resistance at the corresponding intersection points (the area where the upper and lower mesh electrodes overlap spatially, representing the actual pressure detection unit). The magnitude of the applied pressure can then be detected and quantified by the change in resistance.

[0022] like Figure 1 As shown, the flexible pressure sensor in this embodiment includes a flexible upper substrate layer 1, a flexible lower substrate layer 2, a mesh upper electrode 3, a mesh lower electrode 4, and a flexible piezoresistive material 5.

[0023] Both the flexible upper substrate layer 1 and the flexible lower substrate layer 2 are made of fabric-based materials with adhesive layers. The flexible substrate layer (referring to the flexible base structure used to support other functional layers, requiring good mechanical properties and dimensional stability) possesses good flexibility and adhesive properties. The fabric-based material can be cotton, non-woven fabric, polyester fiber fabric, or nylon fabric, etc., and the adhesive layer can be in the form of pressure-sensitive adhesive, hot melt adhesive, or double-sided adhesive. Besides fabric-based materials with adhesive layers, the flexible upper and lower substrate layers can also be made of materials such as polyester film, polyurethane film, or silicone film. Although these materials are not fibrous materials, they also possess good flexibility and can achieve adhesive functionality through surface treatment. The design with adhesive layers allows the subsequent electrodes and piezoresistive materials to be firmly bonded to the substrate layer, while ensuring the overall structural flexibility.

[0024] The mesh upper electrode 3 is arranged on the flexible upper substrate 1 and extends along a first direction (e.g., longitudinal). The mesh lower electrode 4 is arranged on the flexible lower substrate 2 and extends along a second direction (e.g., transverse) that intersects with the first direction. This crisscrossing arrangement allows the mesh upper electrode 3 and mesh lower electrode 4 to form multiple intersection points in space. Each intersection point can serve as an independent pressure detection unit, thereby realizing a multi-point array distribution pressure detection function.

[0025] Both the upper mesh electrode 3 and the lower mesh electrode 4 are composed of conductive webbing. Conductive webbing is a strip-shaped material woven from a mixture of conductive fibers and ordinary fibers, possessing excellent conductivity and flexibility. Besides conductive webbing, mesh electrodes can also be fabricated using conductive ink printing, metal thin film deposition, or conductive polymer coating. These methods can achieve more intricate patterns, but the manufacturing processes are relatively complex. The conductive webbing is fixed to the corresponding substrate layer by adhesive bonding, forming a regular mesh structure. The mesh spacing can be adjusted according to the required detection accuracy, typically ranging from 5-15 cm.

[0026] Flexible piezoresistive material 5 is disposed at the intersection of the mesh upper electrode 3 and the mesh lower electrode 4. In this embodiment, the flexible piezoresistive material 5 is distributed in a discrete point pattern, that is, a small piece of piezoresistive material is placed separately at each intersection. Piezoresistive material refers to a functional material whose resistance value changes accordingly with the pressure it is subjected to. It is a key component for the sensor to realize pressure-to-electrical signal conversion and is made of piezoresistive fabric. It should be noted that the piezoresistive fabric includes a flexible base fabric and conductive fillers dispersed in the flexible base fabric. The flexible base fabric can be polyester fiber, polyurethane, or silicone cloth, etc. The conductive filler refers to functional particles or fibers added to a non-conductive matrix material to impart conductivity. It usually achieves conductivity by forming a conductive network and is made of carbon-based materials, such as carbon black, graphite powder, or carbon nanotubes. In addition to piezoresistive fabric, flexible piezoresistive materials can also be conductive foam, piezoresistive film, or liquid piezoresistive material, etc. Different piezoresistive materials have different pressure response characteristics and detection ranges.

[0027] It should be noted that the conductive filler in the piezoresistive fabric is graphite powder. Graphite powder has good electrical conductivity and chemical stability, and its cost is relatively low. The graphite powder is coated onto the surface of the flexible base fabric to form a uniform conductive layer. Besides graphite powder, other carbon-based materials can also be used as conductive fillers, such as carbon black, carbon nanotubes, graphene, or carbon fibers. Among these, carbon black has good dispersibility and conductivity and is inexpensive, while carbon nanotubes and graphene, although more expensive, have excellent electrical conductivity and mechanical strength. Metallic materials can also be used as conductive fillers, such as silver powder, copper powder, nickel powder, or stainless steel fibers. Silver powder has excellent conductivity but is the most expensive, copper powder has a moderate cost but is prone to oxidation, while nickel powder and stainless steel fibers have good corrosion resistance.

[0028] Compared to traditional strip electrodes, the mesh structure of the upper and lower electrodes offers better flexibility and tensile strength. When the sensor is bent or stretched, the mesh structure effectively disperses stress, preventing electrode breakage. Simultaneously, the mesh structure also provides good breathability, enhancing sensor comfort.

[0029] By staggering the upper and lower electrodes, a large number of detection points can be formed within a limited area, significantly improving the spatial resolution of pressure detection. This design enables the sensor to simultaneously detect pressure at multiple locations and distinguish the pressure magnitude at different locations, making it possible to detect complex pressure distributions.

[0030] Because all its constituent materials are flexible fibers, the entire sensor possesses excellent bendability, foldability, and crumplability. This allows the sensor to conform to various curved surfaces, making it suitable for applications such as wearable devices, robotic skin, and flexible displays.

[0031] In this embodiment, the mesh upper electrode 3 and mesh lower electrode 4 are made of conductive fabric. The conductive fabric is a material that acquires conductivity by plating, coating, or blending ordinary fabric. The conductive fabric forms a mesh structure through sewing, that is, conductive strips are sewn onto a base layer according to a predetermined grid pattern. The advantage of sewing is that the connection is strong and not easily detached, making it suitable for applications requiring frequent bending or stretching.

[0032] Regarding the mesh shape, this embodiment uses a rhombus mesh. Compared to a square mesh, a rhombus mesh has better deformation capacity when stretched diagonally, and can better adapt to complex deformation situations.

[0033] This embodiment uses conductive wires to form a mesh electrode. The conductive wires can be silver-plated copper wire, tin-plated copper wire, or conductive polymer fibers, etc. The conductive wires are braided to form a mesh structure, that is, the conductive wires are woven together in a warp and weft pattern to form a mesh electrode. This braiding method can form a more stable mesh structure while also providing good air permeability.

[0034] In this embodiment, the flexible piezoresistive material 5 is in the form of continuous sheets, covering the mesh upper electrode 3 at multiple intersection points. The advantage of continuous sheets is that the manufacturing process is simple and the cost is lower, while ensuring that there is piezoresistive material at all intersection points, avoiding the omission problem that may occur with discrete point distribution.

[0035] The mesh electrode in this embodiment uses a triangular mesh. The triangular mesh offers optimal structural stability and relatively uniform performance in all directions. This design is particularly suitable for applications requiring multi-directional pressure.

[0036] The above is a detailed description of the preferred embodiments of the present utility model. However, the present utility model is not limited to the described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present utility model. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A flexible pressure sensor, characterized in that, include: Flexible upper substrate; Flexible underlying substrate; A mesh-like upper electrode is disposed on the flexible upper substrate and extends along a first direction; A mesh-like lower electrode is disposed on the flexible lower substrate layer and extends along a second direction intersecting the first direction, such that the mesh-like upper electrode and the mesh-like lower electrode are spatially intersected to form multiple intersection points; A flexible piezoresistive material is disposed at the intersection between the upper mesh electrode and the lower mesh electrode; When pressure is applied to the intersection, the contact area between the upper and lower mesh electrodes through the flexible piezoresistive material increases, resulting in a decrease in resistance at the intersection, thereby enabling pressure detection at the intersection.

2. The flexible pressure sensor according to claim 1, characterized in that, The flexible upper substrate and / or flexible lower substrate are fabric-based materials with adhesive layers.

3. The flexible pressure sensor according to claim 1, characterized in that, The mesh upper electrode and mesh lower electrode are composed of conductive tape, conductive cloth or conductive wire.

4. The flexible pressure sensor according to claim 3, characterized in that, The conductive cloth or conductive wire is formed into a mesh structure by bonding, sewing or weaving.

5. The flexible pressure sensor according to claim 1, characterized in that, The mesh shape of the upper and lower mesh electrodes is square, rhomboid, or triangular.

6. The flexible pressure sensor according to claim 1, characterized in that, The flexible piezoresistive material is in the form of discrete dots or small patches at the intersection.

7. The flexible pressure sensor according to claim 1, characterized in that, The flexible piezoresistive material is a continuous sheet that covers the mesh upper electrode or mesh lower electrode and is located at the multiple intersection points.

8. The flexible pressure sensor according to claim 1, characterized in that, The flexible piezoresistive material is a piezoresistive fabric.

9. The flexible pressure sensor according to claim 8, characterized in that, The piezoresistive fabric includes a flexible base fabric and conductive fillers dispersed in the flexible base fabric or coated on the surface of the flexible base fabric.

10. The flexible pressure sensor according to claim 9, characterized in that, The conductive filler is a carbon-based material.

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