A flexible pressure sensor
By employing a gradient elastic pad and bump design in a flexible pressure sensor, combined with a functional coating, the aging and misjudgment problems of thin-film piezoresistive sensors in extreme environments are solved, achieving sensor performance with high sensitivity and long lifespan.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HUZHOU HUIWEN SENSING TECH CO LTD
- Filing Date
- 2025-10-29
- Publication Date
- 2026-08-04
AI Technical Summary
Existing thin-film piezoresistive sensors are prone to aging under high temperature and humidity or long-term pressure, leading to sensitivity decay, misjudgment, and short service life.
Design a flexible pressure sensor comprising a lower substrate, a circuit layer, a support layer, a pressure-sensitive material layer, and an encapsulation layer. Employ a gradient structure of elastic pads and bumps. The elastic pads deform under external force to transmit pressure and return to their original shape, avoiding direct damage. Combined with a functional coating, reduce adhesion.
It improves the stability and sensitivity of the sensor, extends its service life, reduces the risk of misjudgment, and enhances its shock resistance and durability.
Smart Images
Figure CN224594095U_ABST
Abstract
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] Thin-film piezoresistive sensors, as flexible pressure sensors, are widely used in automotive seats, electric vehicle seats, and 3C electronic push-button switches. However, under prolonged exposure to high temperatures, high humidity, or pressure, thin-film piezoresistive sensors suffer from aging and mechanical fatigue of their constituent materials. This directly leads to challenges in terms of sensor lifespan and stability. Especially in the high-temperature environment inside automobiles and the long-term outdoor use of electric vehicles, material degradation can cause a decrease in sensor sensitivity, or even sensor failure, resulting in false detections of conduction even without pressure. Therefore, improving the stability of thin-film piezoresistive sensors in extreme environments and extending their lifespan is of paramount importance. Utility Model Content
[0003] One objective of this invention is to provide a flexible pressure sensor that solves the technical problem of short service life of existing flexible pressure sensors.
[0004] A further objective of this invention is to ensure the sensitivity of the flexible pressure sensor.
[0005] In particular, this utility model provides a flexible pressure sensor, comprising a lower substrate, a circuit layer, a support layer, a pressure-sensitive material layer and an encapsulation layer arranged sequentially from bottom to top, wherein the encapsulation layer and the lower substrate are both made of flexible material; The flexible pressure sensor also includes an elastic pad, which is located above the encapsulation layer. The area of the elastic pad is smaller than the area of the encapsulation layer and has a gradient structure, with the cross-sectional area of the elastic pad gradually decreasing from bottom to top. The elastic pad is configured to deform under external force and transmit pressure to the pressure-sensitive material layer, causing the pressure-sensitive material layer to contact the circuit layer, thereby putting the flexible pressure sensor in a conductive state; when the external force is removed, it returns to its original shape, causing the pressure-sensitive material layer to separate from the circuit layer, thereby putting the flexible pressure sensor in an open-circuit state.
[0006] Optionally, the elastic pad includes a body and protrusions extending outward from the body, the protrusions being disposed on the side of the body opposite to the encapsulation layer.
[0007] Optionally, the multiple protrusions are divided into multiple protrusion groups, each of which includes multiple protrusions arranged according to a preset pattern. The multiple protrusion groups are arranged along different concentric trajectories to form multiple concentric preset patterns.
[0008] Optionally, the protrusion is hemispherical, and the cross-sectional area of the protrusion gradually decreases from bottom to top.
[0009] Optionally, the height of the protrusions in each group of protrusions is the same.
[0010] Optionally, the height of the protrusions in the multiple sets of protrusions gradually increases from the outside to the inside.
[0011] Optionally, the preset shape is a circle, triangle, quadrilateral, or hexagon.
[0012] Optionally, the interior of the body has a cavity structure or a honeycomb structure.
[0013] Optionally, the support layer has a functional coating on the side away from the pressure-sensitive material layer. The functional coating is located in a region that avoids the elastic pad and is used to reduce the adhesion of the support layer surface.
[0014] Optionally, the support layer is made of PET material or foam; The elastic pad is a silicone pad.
[0015] This utility model discloses a flexible pressure sensor comprising, from bottom to top, a lower substrate, a circuit layer, a support layer, a pressure-sensitive material layer, and an encapsulation layer. Both the encapsulation layer and the lower substrate are made of flexible material. The flexible pressure sensor also includes an elastic pad located above the encapsulation layer. Under external force, the elastic pad deforms and transmits pressure to the pressure-sensitive material layer, causing it to contact the circuit layer. When the external force is removed, it returns to its original shape, separating the pressure-sensitive material layer from the circuit layer. This technical solution, by adding an elastic pad, improves the recovery performance of the flexible pressure sensor, preventing larger forces from being directly transmitted to the sensor and reducing damage. Furthermore, designing the area of the elastic pad to be smaller than the area of the encapsulation layer, and designing the cross-sectional area of the elastic pad to gradually decrease from bottom to top, reduces the impact of the elastic pad design on the sensitivity of the flexible pressure sensor.
[0016] Furthermore, in this invention, the elastic pad includes a body and protrusions extending outward from the body, with the protrusions located on the side of the body away from the encapsulation layer. The above technical solution reduces the force-bearing area by designing protrusions. Under the same total force, the smaller the local contact area, the greater the force on the pressure-sensitive material layer, and the more obvious the output. This improves the sensitivity of the flexible pressure sensor, thereby offsetting the sensitivity loss caused by the added elastic pad.
[0017] The above and other objects, advantages and features of this utility model will become more apparent to those skilled in the art from the following detailed description of specific embodiments of this utility model in conjunction with the accompanying drawings. Attached Figure Description
[0018] The following sections will describe some specific embodiments of the present invention in a detailed manner by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or components. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic structural diagram of a flexible pressure sensor according to an embodiment of the present invention; Figure 2 This is a schematic structural diagram of an elastic pad according to an embodiment of the present invention; Figure 3 This is a schematic layout diagram of the protrusions according to an embodiment of the present invention.
[0019] Figure label: 100-Flexible pressure sensor, 10-Lower substrate, 20-Circuit layer, 30-Support layer, 40-Pressure-sensitive material layer, 50-Encapsulation layer, 60-Elastic pad, 61-Body, 62-Bump. Detailed Implementation
[0020] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.
[0021] In the description of this utility model, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0022] Unless otherwise specified, all terms (including technical and scientific terms) used in the description of this embodiment have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.
[0023] Figure 1 This is a schematic structural diagram of a flexible pressure sensor 100 according to an embodiment of the present invention. Figure 1As shown, in one specific embodiment, the flexible pressure sensor 100 includes, from bottom to top, a lower substrate 10, a circuit layer 20, a support layer 30, a pressure-sensitive material layer 40, and an encapsulation layer 50. The encapsulation layer 50 and the lower substrate 10 are made of flexible material. The flexible pressure sensor 100 also includes an elastic pad 60, located above the encapsulation layer 50. The area of the elastic pad 60 is smaller than that of the encapsulation layer 50, and it has a gradient structure, with the cross-sectional area of the elastic pad 60 gradually decreasing from bottom to top. The elastic pad 60 is configured to deform under external force and transmit pressure to the pressure-sensitive material layer 40, causing the pressure-sensitive material layer 40 to contact the circuit layer 20, thereby putting the flexible pressure sensor 100 in a conductive state. When the external force is removed, it returns to its original shape, causing the pressure-sensitive material layer 40 to separate from the circuit layer 20, thereby putting the flexible pressure sensor 100 in an open-circuit state.
[0024] This embodiment improves the recovery performance of the flexible pressure sensor 100 by adding an elastic pad 60, preventing greater forces from being directly transmitted to the flexible pressure sensor 100 and reducing damage to it. Furthermore, designing the area of the elastic pad 60 to be smaller than the area of the encapsulation layer 50, and designing the cross-sectional area of the elastic pad 60 to gradually decrease from bottom to top, reduces the impact of the elastic pad 60 design on the sensitivity of the flexible pressure sensor 100.
[0025] Figure 2 This is a schematic structural diagram of an elastic pad 60 according to an embodiment of the present invention. Figure 2 As shown, in some embodiments, the elastic pad 60 includes a body 61 and protrusions 62 protruding outward from the body 61, the protrusions 62 being disposed on the side of the body 61 opposite to the encapsulation layer 50.
[0026] This embodiment reduces the force-bearing area by designing protrusions 62. Under the same total force, the smaller the local contact area, the greater the force on the pressure-sensitive material layer 40 and the more obvious the output, which can improve the sensitivity of the flexible pressure sensor 100 and thus offset the sensitivity affected by the newly added elastic pad 60.
[0027] Figure 3 This is a schematic layout diagram of the protrusion 62 according to an embodiment of the present invention. Figure 3 As shown, in some embodiments, the multiple bumps 62 are divided into multiple bump groups, each bump group including multiple bumps 62 arranged according to a preset pattern, and the multiple bump groups are arranged along different concentric trajectories to form multiple concentric preset patterns.
[0028] This embodiment employs a structural design that ensures the protrusions 62 are evenly distributed across the surface of the flexible pressure sensor 100. When external force is applied, the pressure is evenly transmitted and dispersed among the protrusions 62, preventing excessive local stress concentration and significantly improving force uniformity and detection stability. Simultaneously, this arrangement enhances the impact resistance and durability of the flexible pressure sensor 100 while maintaining high sensitivity.
[0029] In some embodiments, the protrusion 62 is hemispherical, and its cross-sectional area gradually decreases from bottom to top. When an external force is applied, the pressure is gradually concentrated and transmitted downwards and outwards from the top of the protrusion 62, making the force application process more gentle and linear, and avoiding instantaneous stress concentration. This not only improves the sensitivity of the flexible pressure sensor 100 to small pressure changes, but also effectively disperses and buffers larger external forces, reducing the risk of damage to the pressure-sensitive material layer 40 and the electrode layer, thereby improving the stability and service life of the flexible pressure sensor 100.
[0030] In some embodiments, the height of the bumps 62 in each group of bumps is the same. In other embodiments, the height of the bumps 62 in each group of bumps can also be designed to be different, which can be determined according to design requirements.
[0031] In some embodiments, the height of the protrusions 62 in the multiple sets of protrusion groups gradually increases from the outside to the inside. When an external force is applied to the elastic pad 60, the lower protrusions 62 in the edge region will preferentially contact and share the initial pressure, and then the higher protrusions 62 on the inner side will gradually participate in the force, thereby forming a step-by-step triggered force-bearing pattern.
[0032] In some embodiments, the preset shape is a circle, triangle, quadrilateral, or hexagon. In other embodiments, the preset shape may be determined according to specific design requirements.
[0033] In some embodiments, the interior of the body 61 has a cavity structure or a honeycomb structure, which can reduce weight and expand its elastic deformation path, thereby increasing the rebound speed and absorbing impact.
[0034] In some embodiments, the support layer 30 is made of PET material or foam. This embodiment improves the support layer 30 of existing pressure sensors by using materials such as PET material or foam, which are more flexible and lower in cost. The recovery performance under high temperature, high humidity and pressure is significantly better than that of traditional double-sided adhesive materials, which can improve the service life of the flexible pressure sensor 100.
[0035] In some embodiments, the elastic pad 60 is a silicone pad. In other embodiments, the elastic pad 60 may also be made of a material having the same properties as silicone.
[0036] In some embodiments, the lower substrate 10 is made of a flexible material, serving as a mechanical support. The circuit layer 20 uses flexible conductive electrodes to form a signal path. The support layer 30 separates the pressure-sensitive material layer 40 from the circuit layer 20 when the flexible pressure sensor 100 is not under stress, preventing short circuits. Here, the middle region of the support layer 30 has a hollow structure, and the pressure-sensitive material layer 40 contacts the circuit layer 20 at the hollow structure after deformation.
[0037] In some embodiments, a functional coating is provided on the side of the support layer 30 away from the pressure-sensitive material layer 40. The functional coating is located in the area away from the elastic pad 60 and is used to reduce the adhesion of the support layer 30 surface.
[0038] This embodiment also processes the encapsulation layer 50, for example, by plasma treatment or by using low surface energy materials such as organosilicon to form a functional coating on the surface of the encapsulation layer 50. This reduces misjudgments caused by the adhesion of the upper covering to the flexible pressure sensor 100 during encapsulation. In the assembly of car and electric vehicle seat cushions, other structures often need to be adhered to the flexible pressure sensor 100. With changes in temperature and humidity, the adhesiveness of the adhesive layer changes. In this case, repeated pressing of the flexible pressure sensor 100 can cause adhesive to adhere to the uppermost encapsulation layer 50, resulting in the flexible pressure sensor 100 being conductive even without external pressure. By processing the encapsulation layer 50 to form a functional coating on its surface, the adhesion between the flexible pressure sensor 100 and the upper covering can be reduced, thereby avoiding the effects of high temperature and humidity on the flexible pressure sensor 100 and improving the sensor's lifespan.
[0039] Therefore, those skilled in the art should recognize that although many exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.
Claims
1. A flexible pressure sensor, characterized by, It includes a lower substrate, a circuit layer, a support layer, a pressure-sensitive material layer and an encapsulation layer arranged sequentially from bottom to top, wherein the encapsulation layer and the lower substrate are both made of flexible material; The flexible pressure sensor also includes an elastic pad, which is located above the encapsulation layer. The area of the elastic pad is smaller than the area of the encapsulation layer and has a gradient structure, with the cross-sectional area of the elastic pad gradually decreasing from bottom to top. The elastic pad is configured to deform under external force and transmit pressure to the pressure-sensitive material layer, so that the pressure-sensitive material layer contacts the circuit layer, thereby making the flexible pressure sensor in a conductive state. When the external force is removed, the system returns to its original state, causing the pressure-sensitive material layer to separate from the circuit layer, thereby putting the flexible pressure sensor in an open-circuit state.
2. The flexible pressure sensor according to claim 1, characterized in that, The elastic pad includes a body and protrusions extending outward from the body, the protrusions being disposed on the side of the body opposite to the encapsulation layer.
3. The flexible pressure sensor according to claim 2, characterized in that, The multiple protrusions are divided into multiple protrusion groups, each of which includes multiple protrusions arranged according to a preset pattern. The multiple protrusion groups are arranged along different concentric trajectories to form multiple concentric preset patterns.
4. The flexible pressure sensor according to claim 3, characterized in that, The protrusion is hemispherical, and its cross-sectional area gradually decreases from bottom to top.
5. The flexible pressure sensor according to claim 4, characterized in that, The height of the bumps in each group of bumps is the same.
6. The flexible pressure sensor according to claim 5, characterized in that, The height of the protrusions in the multiple sets of protrusions gradually increases from the outside to the inside.
7. The flexible pressure sensor according to claim 3, characterized in that, The preset shape is a circle, triangle, quadrilateral or hexagon.
8. The flexible pressure sensor according to any one of claims 2-7, characterized in that, The interior of the body has a cavity structure or a honeycomb structure.
9. The flexible pressure sensor according to any one of claims 1-7, characterized in that, The support layer has a functional coating on the side away from the pressure-sensitive material layer. The functional coating is located in the area away from the elastic pad and is used to reduce the adhesion of the support layer surface.
10. The flexible pressure sensor according to any one of claims 1-7, characterized in that, The support layer is made of PET material or foam. The elastic pad is a silicone pad.