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CN-122016132-A - Flexible three-dimensional multidirectional force sensing detection array device and preparation method thereof

CN122016132ACN 122016132 ACN122016132 ACN 122016132ACN-122016132-A

Abstract

The invention discloses a flexible three-dimensional multidirectional force sensing detection array device and a preparation method thereof. The device comprises a flexible substrate layer, an arrayed three-dimensional trapezoidal sensing unit, an upper and lower double-layer electrode structure, a through conductive hole, a liquid metal conductive layer and a packaging layer. The three-dimensional trapezoidal sensing unit consists of four subunits distributed along the 90-degree direction, so that a 360-degree space sensing structure is formed, and multidimensional response to normal force and tangential force can be realized. The upper electrode layer and the lower electrode layer are electrically connected through the through conductive holes to form a three-dimensional conductive path, the liquid metal layer is used for enhancing conductive continuity and flexibility, and the encapsulation layer adopts an Ecoflex elastomer to improve stability. The device realizes three-dimensional directional force signal decoupling through opposite side difference and amplitude ratio inverse solution, has high sensitivity, multi-direction detection and excellent stretchable characteristics, and is suitable for the fields of bionic electronic skin, wearable equipment, touch interaction systems and the like.

Inventors

  • HUANG ZHENLONG
  • WU TAILONG
  • LIN YUAN
  • XIE HONGWEI

Assignees

  • 电子科技大学

Dates

Publication Date
20260512
Application Date
20260309

Claims (9)

  1. 1. The flexible three-dimensional multidirectional force sensing detection array device is characterized by comprising a flexible substrate layer, a three-dimensional sensing array, an upper and a lower double-layer electrode structure, a conductive hole, a liquid metal conductive layer and a packaging layer; the flexible substrate layer is formed by compounding Polydimethylsiloxane (PDMS) and tin antimony oxide (ATO), a three-dimensional sensing whole column is arranged on the flexible substrate layer and consists of three-dimensional sensing units, each three-dimensional sensing unit is formed by compounding Polydimethylsiloxane (PDMS), tin antimony oxide (ATO) and Carbon Nano Tubes (CNT), four trapezoidal induction sub-units distributed along the 90-degree direction are formed by compounding, the four square induction sub-units together form a 360-degree space force sensing structure to convert mechanical strain into resistance change signals, the upper double-layer electrode structure comprises an upper electrode positioned on the upper surface of the flexible substrate layer, a lower electrode positioned on the lower surface of the flexible substrate layer and a metal wire, the same positions of the upper electrode and the lower electrode structure correspond to each other, the upper electrode and the lower electrode structure both comprise a central electrode and four distributed electrodes along the 90-degree direction, the central electrode of the upper electrode is connected with one end of the four trapezoidal induction sub-units, the central electrode and the four distributed electrodes of the upper electrode are respectively correspondingly connected with the four trapezoidal induction sub-units, the central electrode and the four distributed electrodes of the lower electrode are correspondingly connected with the upper electrode through the upper electrode and the lower electrode through the upper electrode of the upper electrode structure, the upper electrode and the upper electrode structure is connected with the upper electrode of the upper electrode structure through the upper electrode and the upper electrode of the upper electrode structure and the upper electrode structure is connected with the metal wire of the upper electrode structure through the metal wire, the packaging layer is Ecoflex elastomer and is used for sealing and protecting the sensing structure.
  2. 2. The device of claim 1, wherein the internal angle of the bench-like induction subunit is 20 °, 40 °, 60 °, or 80 °.
  3. 3. The device according to any one of claims 1-2, wherein the array is a 5 x 5 or higher density matrix structure, the spacing between adjacent cells is 2.5 mm, and the electrode interconnect of each cell adopts a stretchable serpentine wiring structure to ensure that the array maintains stable signals in 10% -30% stretching state.
  4. 4. The device according to any one of claims 1-2, wherein the upper and lower double-layer electrode structures are formed on the flexible substrate by laser etching, etching paths correspond to the independent electrode areas in four directions, the etching depth is 0.1-0.3 mm, and the upper electrode and the lower electrode are perforated after laser etching to form through holes.
  5. 5. The device of claim 4, wherein the upper and lower double electrode structures are formed into conductive paths by double-stage electroless copper plating, the first stage is reacted at 35 ℃ for 2 hours to accelerate preliminary deposition of copper ions in etched gaps, the second stage is continued at room temperature for 25 ℃ for 4 hours to achieve sufficient deposition and complete coverage, and the electroless copper plating process is performed on the back side and then flipped over to perform front side plating to ensure complete penetration of the copper layer.
  6. 6. The device of claim 5, wherein the liquid metal conductive layer is formed by brushing, the liquid metal is gallium indium tin alloy, the surface tension is controlled to be 35-40 mN/m, and the surface is subjected to plasma treatment to enhance the binding force with the Ecoflex packaging layer.
  7. 7. The preparation method of the flexible three-dimensional multi-directional force sensing detection device according to any one of claims 1-2 is characterized by comprising the steps of 1) preparing a flexible device reverse mould by adopting a 3D printing technology, 2) injecting mixed liquid of PDMS (polydimethylsiloxane) ATO (carbon nanotube) and CNT=100:5:5 into the mould, curing to form a three-dimensional sensing structure, 3) continuously pouring PDMS without CNT into the bottom of an upper layer structure to form an isolation layer, integrally curing and demoulding, 4) forming an electrode and a conductive path on the upper surface and the lower surface by using a laser etching technology, 5) punching at a preset position after laser etching, 6) conducting two-step electroless copper plating, wherein the first step is conducted for accelerating deposition at 35 ℃ for 2 hours and the second step is conducted for 4 hours and completely depositing at 25 ℃, 7) overturning the front surface and the back surface of a sample, copper plating at the electrode and the conductive path of the laser etching in sequence, 8) brushing a liquid metal conductive layer at the conductive path of the back surface, and 9) packaging the top layer and the bottom layer by using Ecoflex.
  8. 8. A three-dimensional directional force decoupling method based on a flexible three-dimensional multidirectional force sensing detection device according to any one of claims 1-2 is characterized in that unit four-channel signals are adopted for calculation, tangential direction angles phi are determined through opposite edge differences, inclination angles alpha are reversely decoupled through combination of single-channel relative gain or differential amplitude ratio and calibration curves, normal load Fz is represented by four-channel means, and therefore three-dimensional directional decoupling detection of a single pressure sensor is achieved.
  9. 9. The decoupling method of claim 8, wherein the direction angle θ is calculated from the opposite side channel differential signals: Wherein The resistance values of the four channels are respectively obtained, the inclination angle alpha is obtained through the inverse calculation of a single-channel differential amplitude ratio and a calibration curve, and the normal load Fz is the arithmetic average value of four-channel output: Where k is the calibration factor.

Description

Flexible three-dimensional multidirectional force sensing detection array device and preparation method thereof Technical Field The invention belongs to the technical field of flexible electronic devices, and particularly relates to a flexible three-dimensional multidirectional force sensing detection array device for multidimensional force detection and a preparation method thereof. The device can realize independent measurement and decoupling detection of normal force and tangential force, and is suitable for flexible sensing application scenes such as wearable electronics, bionic electronic skin, intelligent robots, man-machine interaction and the like. Background Along with the rapid development of flexible electronic technology, the traditional rigid sensor has limited application in complex deformation environment due to high material rigidity, fixed form and poor adaptability. The flexible sensor gradually becomes an important component in the fields of new-generation intelligent wearable systems, medical monitoring equipment, bionic electronic skin and the like by virtue of good flexibility, stretchability and attachability. Among the flexible sensor types, the flexible pressure sensor is used as a key device for converting an external mechanical pressure or strain signal into an electric signal, and has the advantages of high sensitivity, low power consumption and good flexibility. However, most of the current flexible pressure sensors can only realize detection in a single direction (such as normal force), and in a scene involving multi-directional stress (including shearing force, stretching force, torsion force and the like), signal coupling and response aliasing phenomena often occur, so that measurement accuracy is reduced, and independent identification of three-dimensional components of force is difficult to realize. In order to solve the problems, it is very important to explore a flexible sensing unit based on a three-dimensional structure, and stress responses in different directions are distinguished in a space dimension through a three-dimensional trapezoid or multi-layer stacked structure, so that multi-directional force decoupling detection is realized. Meanwhile, the detection sensitivity and the direction judgment precision of the normal force and the tangential force can be further improved by combining the algorithm of the multi-channel signal difference and the calibration model. However, the existing flexible three-dimensional sensor still has limitations in terms of structural integration, signal conduction path design and array preparation. For example, the problems of unstable interconnection between the upper electrode and the lower electrode, insufficient stretchability of the array, complex multi-directional signal decoupling algorithm and the like restrict the application of the array in high-density arrays and complex stress environments. Therefore, a flexible three-dimensional sensing array device with stable structure, clear conductive path and capability of realizing multi-directional force decoupling detection is urgently needed, so that the comprehensive performance of a flexible electronic system in space force sensing and interaction detection is improved. Disclosure of Invention The invention aims to overcome the defects that the existing flexible pressure sensor can only detect unidirectional force, is easy to generate signal coupling under multidirectional stress, has low array integration level, unstable conductive paths and the like, and provides a flexible three-dimensional multidirectional force sensing detection array device and a preparation method thereof. The device realizes high-density arrayed arrangement on the flexible substrate by constructing a sensing unit with a trapezoid three-dimensional structure and combining an upper double-layer conductive electrode, a lower double-layer conductive electrode and a through conductive hole structure, and simultaneously realizes independent identification of normal force, tangential force and inclination angle by a three-dimensional force decoupling algorithm based on multi-channel signal difference, thereby improving the detection precision and the direction resolution capability of the sensor and meeting the multidimensional force sensing requirement under a complex stress scene. The technical scheme adopted by the invention is as follows: In a first aspect, a flexible three-dimensional multi-directional force sensing array device is provided, including a flexible substrate layer, a three-dimensional trapezoidal sensor array, an upper and a lower double-layer electrode structure, a through conductive hole, a liquid metal conductive layer and a packaging layer. The three-dimensional trapezoidal sensor consists of four sub-sensing units distributed along the 90-degree direction to form a 360-degree space sensing structure for converting stress signals in different directions into resistance change signals, wh