CN-121994381-A - Flexible pressure sensor of rigidity gradient micro-cone array and manufacturing method thereof

CN121994381ACN 121994381 ACN121994381 ACN 121994381ACN-121994381-A

Abstract

The invention discloses a flexible pressure sensor of a rigidity gradient micro-cone array and a manufacturing method thereof, belonging to the technical field of flexible sensor structural design and manufacturing; the sensor comprises an upper packaging layer, an upper electrode layer, a sensitive layer, a lower electrode layer and a lower packaging layer which are sequentially stacked from top to bottom, wherein the upper end of the sensitive layer is electrically connected with the upper electrode layer, the lower end of the sensitive layer is electrically connected with the lower electrode layer, the sensitive layer is of an elastomer micro-cone array structure, at least two layers of elastomer stacks with different elastic moduli are built on a single micro-cone along the height direction, so that an axial rigidity gradient is formed from the top to the bottom of the micro-cone, a conductive layer is coated on the surface of the sensitive layer, the conductive layer is used for generating electrical parameter change along with the contact state change of the micro-cone and the upper electrode layer under the pressure effect so as to realize pressure detection, and the sensor can realize high-response and wide-range collaborative lifting and is suitable for wearable, man-machine interaction, soft robot touch and other scenes.

Inventors

ZHOU WEI
HAN YU
LI YU
LI SHIXUAN
DUAN YUANZHEN
DAI YINGYING

Assignees

厦门大学

Dates

Publication Date: 20260508
Application Date: 20260206

Claims (10)

1. The flexible pressure sensor of the rigidity gradient micro-cone array is characterized by comprising an upper packaging layer, an upper electrode layer, a sensitive layer, a lower electrode layer and a lower packaging layer which are sequentially stacked from top to bottom, wherein the upper end of the sensitive layer is electrically connected with the upper electrode layer, and the lower end of the sensitive layer is electrically connected with the lower electrode layer; the sensitive layer is an elastomer micro-cone array structure, and a single micro-cone constructs at least two layers of elastomer laminates with different elastic moduli along the height direction, so that the micro-cone forms an axial rigidity gradient from the top to the bottom; The surface of the sensitive layer is coated with a conductive layer, and the conductive layer is used for generating electrical parameter change along with the change of the contact state of the micro cone and the upper electrode layer under the action of pressure so as to realize pressure detection.
2. A flexible pressure sensor of a rigidity gradient micro-cone array is characterized in that the elastic body lamination is of a three-layer structure, the elastic body lamination is sequentially provided with a soft layer, a middle layer and a hard layer from top to bottom, the Young modulus of the soft layer is smaller than that of the middle layer, the Young modulus of the middle layer is smaller than that of the hard layer, the lower ends of the hard layers are connected to form a block, the upper ends of the hard layers, the middle layer and the soft layer form micro-cones which are arranged at intervals, and the cross section of the micro-cones gradually increases from top to bottom.
3. The flexible pressure sensor of the rigidity gradient micro cone array of claim 1, wherein said sensitive layer is electrically equivalent to a network of two ends between an upper electrode layer and a lower electrode layer, and its port equivalent resistance is denoted as R eq (p), wherein p is the external pressure, and said R eq (p) monotonically decreases with the external pressure in the working pressure interval.
4. A flexible pressure sensor of a stiffness gradient micro-cone array according to claim 3, wherein R eq (p) is read out by adopting a voltage division mode, an equivalent resistor R eq (p) is connected with a reference resistor R ref in series and an excitation voltage V exc is applied, and output voltages V o (p) at two ends of the reference resistor are sampled, so that the following calculation formula is satisfied: , And under the condition that the R eq (p) monotonically decreases, the V o (p) monotonically increases with an increase in the external pressure.
5. The flexible pressure sensor of claim 4, wherein the reference resistor R ref satisfies the following calculation formula for the output voltage V o (p) to fall within the target pressure interval [ p min ,p max ] within the preset measurement window [ V L ,V H ]: , Wherein R min =R eq (p max ), R min is the equivalent resistance when the target pressure is p max , and R max =R eq (p min ), R max is the equivalent resistance when the target pressure is p min .
6. A flexible pressure sensor of a stiffness gradient micro-cone array as set forth in claim 1, wherein said micro-cones are one or more of conical, pyramidal, or pyramidal, and wherein said micro-cones are arranged in a regular array.
7. The flexible pressure sensor of the rigidity gradient micro cone array of claim 1, wherein the conductive layer is made of one or more of carbon nano tube, carbon black, graphene, MXene, conductive polymer or metal nanowire, the upper electrode layer and the lower electrode layer are made of one or more of gold, silver, copper or aluminum, and the upper packaging layer and the lower packaging layer are made of one or two of polyimide film or elastomer film.
8. A method of manufacturing a flexible pressure sensor of a stiffness gradient micro-cone array according to any of claims 1-7, comprising the steps of: S1, preparing at least two elastomer layers with different Young' S moduli, and respectively curing and forming; S2, carrying out surface activation and lamination on the adjacent elastomer layers to realize interlayer interface bonding, and obtaining the gradient elastic substrate with layered axial elastic modulus; S3, performing laser material reduction processing on the gradient elastic substrate to form a gradient micro-cone array substrate; S4, preparing a conductive layer on the surface of the gradient micro-cone array substrate to obtain a sensitive layer; And S5, sequentially integrating and packaging the upper packaging layer, the upper electrode layer, the sensitive layer, the lower electrode layer and the lower packaging layer to form the flexible pressure sensor of the rigidity gradient micro-cone array.
9. The method of claim 8, wherein in the step S1, the elastomer layer is one or more of polydimethylsiloxane, ecoflex and polyurethane, and when the elastomer layer is made of polydimethylsiloxane, different Young' S moduli are obtained by different proportions of base rubber and curing agent.
10. The method of manufacturing a flexible pressure sensor with a gradient micro-cone array according to claim 8, wherein in step S2, the surface activation is plasma activation, and in step S3, the laser subtractive processing is an infrared sheath second laser or a femtosecond laser processing.

Description

Flexible pressure sensor of rigidity gradient micro-cone array and manufacturing method thereof Technical Field The invention belongs to the technical field of flexible sensor structural design and manufacturing, and particularly relates to a flexible pressure sensor with a rigidity gradient micro-cone array and a manufacturing method thereof. Background The flexible pressure sensor is widely applied to wearable electronics, health monitoring, man-machine interaction, electronic skin and soft robot touch systems due to being bendable and capable of being attached to complex curved surfaces. Piezoresistive flexible pressure sensors typically achieve pressure detection by a change in resistance of a conductive network or a change in interface contact resistance due to pressure. The existing micro-structure arrays such as micro hemispheres, micro columns and micro cones can improve low-pressure response, but when the structure or material is too soft, the micro-structure arrays are easy to compact rapidly in a medium-high pressure area and saturated in advance, and when the structure is too hard, the low-pressure deformation is insufficient to cause the response to be reduced, so that the problem that both high response and wide range are difficult to achieve is formed. Meanwhile, the viscoelasticity and interface sliding in cyclic loading are easy to introduce hysteresis and drift, and the repeatability and long-term stability are affected. Thus, there is a need for a flexible pressure sensor solution that is repeatable in structure and process and that can maintain a measurable output over a wide pressure range. Disclosure of Invention In order to solve the problems, the invention provides a flexible pressure sensor of a rigidity gradient micro-cone array and a manufacturing method thereof, wherein the sensor drives a micro-cone to deform and bear step by axial rigidity gradient under the action of external pressure, so that the contact state continuously evolves, and the port equivalent resistance keeps measurable change in a wide range and can be read as a voltage signal; the manufacturing method comprises the steps of preparing elastomer layers with different Young modulus, solidifying, performing surface activation lamination to form a gradient elastic substrate, performing laser material reduction processing to form a gradient micro-cone array, preparing a conductive layer to obtain a sensitive layer and laminating and packaging. In order to achieve the above purpose, the present invention adopts the following technical scheme: The flexible pressure sensor comprises an upper packaging layer, an upper electrode layer, a sensitive layer, a lower electrode layer and a lower packaging layer which are sequentially stacked from top to bottom, wherein the upper end of the sensitive layer is electrically connected with the upper electrode layer, and the lower end of the sensitive layer is electrically connected with the lower electrode layer; the sensitive layer is an elastomer micro-cone array structure, and a single micro-cone constructs at least two layers of elastomer laminates with different elastic moduli along the height direction, so that the micro-cone forms an axial rigidity gradient from the top to the bottom; The surface of the sensitive layer is coated with a conductive layer, and the conductive layer is used for generating electrical parameter change along with the change of the contact state of the micro cone and the upper electrode layer under the action of pressure so as to realize pressure detection. The elastic body lamination is of a three-layer structure, the elastic body lamination is sequentially provided with a soft layer, a middle layer and a hard layer from top to bottom, the Young modulus of the soft layer is smaller than that of the middle layer, the Young modulus of the middle layer is smaller than that of the hard layer, the lower ends of the hard layer are connected to form a block, the upper ends of the hard layer, the middle layer and the soft layer form microcones which are arranged at intervals, and the cross section of each microcone is gradually increased from top to bottom. Preferably, the sensitive layer is electrically equivalent to a network at two ends between the upper electrode layer and the lower electrode layer, the port equivalent resistance of the sensitive layer is denoted as R eq (p), wherein p is the external pressure, and the R eq (p) monotonically decreases along with the increase of the external pressure in a working pressure interval. Preferably, R eq (p) is read out by adopting a voltage division mode, namely, an equivalent resistor R eq (p) is connected in series with a reference resistor R ref and an excitation voltage V exc is applied, and the output voltage V o (p) at two ends of the reference resistor is sampled, so that the following calculation formula is satisfied: , And under the condition that the R eq (p) monotonically decreases, the V o (p) mon