Jigsaw-imitated multi-stage alternating interlocking structure sensing electrode and manufacturing method thereof

Abstract

The invention discloses a jigsaw-imitated multi-stage alternating interlocking structure sensing electrode and a manufacturing method thereof, and belongs to the field of micro-nano manufacturing, and the jigsaw-imitated multi-stage alternating interlocking structure sensing electrode specifically comprises a flexible substrate, a circular electrode element, a rectangular electrode element, a packaging layer and a copper-plated circuit; each of the circular electrode element and the rectangular electrode element is composed of a first-stage bionic interlocking micro-puzzle structure and a second-stage ultrathin and superfine porous structure, interface interlocking is formed between the upper layer and the lower layer of the electrode element through the mechanical meshing effect of the first-stage structure, structural hardening is avoided through the reversible reconstruction effect of the second-stage structure, and the super-sensitive sensing and super-wide response characteristics are achieved. And the contradiction that the sensitivity and the response range of the piezoresistive sensing device are difficult to obtain at the same time is solved. The invention further provides a manufacturing method of the sensing electrode, laser etching-induction and silica gel pouring-transfer printing procedures are combined in sequence, the micro-nano manufacturing limitation of an imitation jigsaw multi-stage alternating interlocking structure is broken through, and the stability of the sensing electrode is greatly improved through the multi-stage structure interface interlocking design.

Description

Technical Field

[0001] The invention belongs to the technical field of sensor micro-nano manufacturing, and particularly relates to a jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode and a manufacturing method thereof. Background Art

[0002] As sensors are used more and more widely in people's daily work and life, people's requirements for the comfort of their usage experience are getting higher and higher, which makes the development of wearable sensors receive more attention.

[0003] Traditional sensing electrodes have the disadvantages of complex processing technology, poor stability, sensitivity and adaptability. In the development of sensing electrodes, there is an urgent need for a sensing electrode that can simplify the processing technology and have good performance. The jigsaw puzzle microstructure electrode uses the jigsaw puzzle interlocking function at the interface to improve the sensitivity, stability and adaptability of the device. The interlocking microstructure not only increases the surface area of ​​the electrode and improves the efficiency of signal acquisition, but also enhances the mechanical strength and durability, enabling it to work stably in complex environments.

[0004] Chinese invention patent CN111521305B discloses a bionic sensor for measuring mechanical signals and a manufacturing method thereof, including a sensor unit, a sensor bracket, and a resistance detection device, wherein the sensor unit includes a flexible substrate layer, and hair rods and a signal processing layer on the flexible substrate layer. The invention mainly improves the sensitivity of the device by obtaining a large resistance change during the measurement process in which the cracks on the signal processing layer follow the deformation process of the flexible substrate layer, and has strong adaptability to multiple mechanical signals in space and planes. However, the invention does not involve improving the sensitivity, stability and adaptability, and reducing the manufacturing complexity and cost through the multi-level alternating interlocking structure design of the sensing electrode. The sensing electrode described in the present invention is a multi-level alternating interlocking sensor composed of a primary bionic interlocking microstructure and a secondary ultra-thin and ultra-fine porous structure, which improves the interface interlocking fit and sensing performance of the sensing electrode. The laser etching-induced pre-treatment process and the silicone casting-stripping composite combined processing method are introduced to construct the surface bionic micro-puzzle structure while retaining the internal ultra-thin and ultra-fine porous structure. Different from the traditional single induction or induced transfer route, the etching and transfer processes are combined front and back to break through the inherent structural limitations of traditional electrodes.

[0005] Chinese invention patent CN110329986B discloses a bionic flexible force sensor and its preparation method, wherein the bionic flexible force sensor includes blades, polydimethylsiloxane primary mold, polydimethylsiloxane secondary mold, positive friction layer electrode, shielding layer, microhair, and negative friction layer back electrode. The invention mainly uses the bionic microstructure of the positive friction layer to interlock with the bionic microstructure of the negative friction layer to form an interlocking. When subjected to force, the actual area of ​​friction contact is larger than that of an ordinary flat sensor, thereby improving the output signal of the sensor, thereby improving the stability and sensitivity of the sensor. However, the bionic structure of the invention has a certain gap in improving the sensitivity of the sensor compared to the bionic multi-level structure of the present invention, especially the combination of the primary bionic puzzle microstructure and the secondary ultra-thin and ultra-fine porous structure. The present invention achieves alternate interlocking through the synergistic enhancement effect of interface piezoresistance. When subjected to external stress, the primary bionic micro-puzzle structures are mechanically meshed at the interface, which can contribute excellent resistance response effects at different scales. The extremely high degree of fit will have stronger interface stability than traditional structures. When the stress is concentrated on the secondary ultra-thin and ultra-fine porous structure from the outside to the inside, it will form a predictable transmission and expansion along the ultra-thin and ultra-fine skeleton. The adaptive porous structure compensates for the stroke difference through reversible compression and recovery, avoids structural hardening, and improves the sensitivity and response range at the same time with the advantages of ultra-sensitive perception and ultra-wide response structure. Summary of the invention

[0006] The purpose of the present invention is to address the deficiencies of the prior art and provide a jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode and a manufacturing method thereof, thereby realizing the design and low-cost and high-efficiency manufacturing of a new type of sensing electrode.

[0007] The above technical objectives of the present invention are achieved through the following technical solutions: a jigsaw-like multi-stage alternating interlocking structure piezoresistive sensing electrode and a manufacturing method thereof, characterized in that the jigsaw-like multi-stage alternating interlocking structure piezoresistive sensing electrode comprises a flexible substrate, a circular electrode element, a rectangular electrode element, a packaging layer, and a copper-plated circuit; the circular electrode element and the rectangular electrode element are composed of a primary bionic interlocking micro-jigsaw structure and a secondary ultra-thin and ultra-fine porous structure, the primary structure is used for mechanical meshing between the upper and lower layers of the electrode element to achieve interface interlocking, the secondary structure is used for reversible reconstruction to avoid structural hardening, and an alternating arrangement is used for silicone packaging; the manufacturing method of the jigsaw-like multi-stage alternating interlocking structure piezoresistive sensing electrode comprises the following steps:

[0008] S1 Laser Etching-Induced Front-end Process: Bionic design is performed based on the jigsaw puzzle structure, and then ultraviolet pulse laser is used for etching and removal, and infrared pulse laser is used for continuous induced growth;

[0009] S2 silicone casting-transfer back-end process: liquid silicone is used for casting, vacuum heating and curing, and then silicone encapsulation is performed after transfer.

[0010] Specifically, the S1 laser etching-induced front-end process includes the following steps:

[0011] S101 Bionic Design: Linear regression method is used to normalize the jigsaw puzzle structure parameters and then pattern design is performed;

[0012] S102 laser etching: using ultraviolet nanosecond pulse laser, with laser power of 1.0-3.0W and scanning rate of 50-100mm / s, to etch a primary bionic micro-jigsaw structure with alternating depressions on the surface of the polyimide film;

[0013] S103 laser induction: Using an infrared continuous CO2 laser, under the processing parameters of laser power of 0.5-2.0W and scanning rate of 20-100mm / s, a secondary porous structure with ultra-thin pore size / extremely fine pore wall is induced to grow on the concave primary bionic micro-jigsaw structure.

[0014] Specifically, the S2 silica gel casting-transfer back-end process includes the following steps:

[0015] S201 liquid casting: Prepare the AB components of Ecoflex liquid silicone in a mass ratio of 1:1, cast them on the primary structure of the electrode and pressurize them after they are completely filled, so that the silicone can fully penetrate into the secondary ultra-thin and fine porous structure.

[0016] S202 curing transfer: vacuum heating treatment is used, the pressure is set to -1.5MPa, the pressurization time is 30 minutes, the temperature is set to 80℃, and the heating time is 3 hours to completely solidify the liquid silicone; after cooling, the transfer mold is removed, and the silicone material is peeled off from the polyimide film to construct a jigsaw puzzle-like multi-level alternating interlocking structure;

[0017] S203 silicone package: First, cut the silicone film according to the shape of the sensor electrode, apply conductive silver paste and heat it at 120°C, then use copper foil to lead out the wires on the two electrodes and fit the package with gaps reserved around them.

[0018] Furthermore, the size of the first-level bionic interlocking micro-jigsaw structure of the jigsaw-like multi-level alternating interlocking structure sensing electrode is between 50 and 100 μm, the size of the holes of the second-level ultra-thin and ultra-fine porous structure is between 3 and 5 μm, and the wall thickness is between 20 and 40 nm.

[0019] Furthermore, the S102 laser etching step utilizes the principle of ultraviolet light chemistry to vaporize molecular chains to remove materials and weaken the carbonization effect; the S103 laser induction step utilizes the principle of infrared light heat to ablate molecular chains to induce the growth of materials and strengthen the carbonization effect.

[0020] Furthermore, in the S202 curing transfer step, the recessed micro-puzzle template is invertedly transplanted onto the surface of the silicone elastomer to construct a primary bionic micro-puzzle structure with raised surface, while retaining the internal secondary ultra-thin and ultra-fine porous structure; in the S203 silicone encapsulation step, the copper foil wire on the electrode does not contact with another electrode, and a certain weight is placed during the bonding process to ensure perfect bonding between the electrodes.

[0021] Furthermore, the operating principle of the jigsaw-like multi-level alternating interlocking structure sensing electrode is to perform alternating interlocking of interfaces through the piezoresistive synergistic enhancement effect. When subjected to external stress, the primary bionic micro-jigsaw structures are mechanically engaged at the interface, which can contribute excellent resistance response effects at different scales. The extremely high degree of fit will have stronger interface stability than traditional structures. When the stress is concentrated on the secondary ultra-thin and ultra-fine porous structure from the outside to the inside, it will form a predictable transmission and expansion along the ultra-thin and ultra-fine skeleton, and compensate for the stroke difference through reversible compression and recovery to avoid structural hardening. The advantages of ultra-sensitive perception and ultra-wide response structure are used to jointly resolve the contradiction between device sensitivity and response range that is difficult to achieve at the same time.

[0022] Compared with the existing technology, the above-mentioned jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode and its manufacturing method have the following beneficial effects.

[0023] ① It has both sensitivity and response range. Through the piezoresistance synergistic enhancement effect, the interface is alternately interlocked. The first-level bionic micro-puzzle structure can contribute excellent resistance response effects at different scales. The second-level ultra-thin and ultra-fine porous structure compensates for the travel difference through reversible compression and recovery. The advantages of ultra-sensitive perception and ultra-wide response structure are used to jointly resolve the contradiction between device sensitivity and response range.

[0024] ②Good stability. When the sensing electrode is subjected to external stress, the bionic micro-jigsaw structures are mechanically engaged at the interface, and the excellent structural fit has stronger interface stability;

[0025] ③ High degree of integration. Taking advantage of the ultra-thin and ultra-fine porous microstructure that can effectively avoid structural hardening and the bionic interlocking microstructure that can improve interface stability, a multi-level alternating interlocking structure was constructed and designed to improve the degree of integration of the sensing electrode.

[0026] ④ Advanced manufacturing technology. The laser etching-induction pre-treatment process and the silicone casting-peeling composite processing method are introduced to construct the surface bionic micro-jigsaw structure while retaining the internal ultra-thin and ultra-fine porous structure. Different from the traditional single induction or induction transfer route, it breaks through the inherent structural limitations of traditional electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the overall structure of the jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode in the present invention;

[0028] Figure 2 It is a schematic diagram of the structure of the circular electrode element and the rectangular electrode element in the present invention;

[0029] Figure 3 is a schematic diagram of a primary bionic interlocking micro-jigsaw structure in the present invention;

[0030] Figure 4 It is a schematic diagram of the secondary ultra-thin and ultra-fine porous structure in the present invention;

[0031] Figure 5 It is a manufacturing flow chart of the jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode in the present invention;

[0032] Figure 6 It is a schematic diagram of the manufacturing principle of the jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode in the present invention;

[0033] Figure 7 It is a schematic diagram of the interface interlocking principle of the jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode in the present invention;

[0034] Figure 8 This is a physical diagram of the interface interlocking of the sensing electrode of the jigsaw puzzle-like multi-level alternating interlocking structure in the present invention;

[0035] above Figures 1 to 8 The markings are: 1. flexible substrate, 2. circular electrode element, 3. rectangular electrode element, 4. packaging layer, 5. copper-plated circuit. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0037] Inspired by the jigsaw puzzle structure, in order to solve the problems of low sensitivity, slow responsiveness, poor stability, complex manufacturing process, etc. of existing sensors, the present invention provides a jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode and a manufacturing method thereof.

[0038] The jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode has a structure such as Figure 1 As shown, it includes a flexible substrate 1, a circular electrode element 2, a rectangular electrode element 3, a packaging layer 4, and a copper-plated circuit 5.

[0039] The circular electrode elements and rectangular electrode elements are composed of a primary bionic interlocking micro-jigsaw structure and a secondary ultra-thin and ultra-fine porous structure. The primary structure is used for mechanical meshing between the upper and lower layers of the electrode elements to achieve interlocking interfaces, and the secondary structure is used for reversible reconstruction to avoid structural hardening. At the same time, an alternating arrangement is used for silicone encapsulation.

[0040] Furthermore, the method for manufacturing the bionic interlocking micro-jigsaw structure sensing electrode comprises the following steps:

[0041] S1 Laser Etching-Induced Front-end Process: Bionic design is performed according to the jigsaw puzzle structure, and then ultraviolet pulse laser is used for etching, and infrared pulse laser is used for continuous laser induction;

[0042] S2 silicone casting-transfer back-end process: liquid silicone is used for casting, vacuum heating and curing, and then silicone encapsulation is performed after transfer.

[0043] Furthermore, the S1 laser etching-induced front-end process comprises the following steps:

[0044] S101 Bionic Design: Linear regression method is used to normalize the jigsaw puzzle structure parameters and then pattern design is performed;

[0045] S102 laser etching: Using ultraviolet nanosecond pulse laser, under the processing parameters of laser power of 1.0-3.0W and scanning rate of 50-100mm / s, the principle of ultraviolet photochemistry is used to vaporize molecular chains to remove materials and weaken the carbonization effect, and an alternating concave primary bionic micro-jigsaw structure is etched on the surface of the polyimide film;

[0046] S103 laser induction: using infrared continuous CO2 laser, with laser power of 0.5-2.0W and scanning rate of 20-100mm / s, the infrared photothermal principle is used to ablate molecular chains to induce the growth of materials and strengthen the carbonization effect, inducing the growth of a secondary porous structure with ultra-thin pore size / extremely fine pore wall on the concave primary bionic micro-jigsaw structure.

[0047] Furthermore, the S2 silica gel casting-transfer back-end process includes the following steps:

[0048] S201 liquid casting: Prepare the AB components of Ecoflex liquid silicone in a mass ratio of 1:1, cast them on the primary structure of the electrode and pressurize them after they are completely filled, so that the silicone can fully penetrate into the secondary ultra-thin and fine porous structure.

[0049] S202 curing transfer: vacuum heating treatment is used, the pressure is set to -1.5MPa, the pressurization time is 30 minutes, the temperature is set to 80℃, and the heating time is 3 hours to completely solidify the liquid silicone; after cooling, the transfer mold is removed, and the silicone material is peeled off from the polyimide film. The concave micro-puzzle template can be inverted and transplanted to the surface of the silicone elastomer to construct a primary bionic micro-puzzle structure with raised surface, while retaining the internal secondary ultra-thin and ultra-fine porous structure to form a multi-level alternating interlocking structure imitating a puzzle;

[0050] S203 silicone packaging: First, cut the silicone film according to the shape of the sensor electrode, apply conductive silver paste and heat it at 120℃, then use copper foil to lead out the wires on the two electrodes and fit the blanks reserved around the package. During this process, the copper foil wire on the electrode does not contact the other electrode, and a certain weight is placed during the bonding process to ensure perfect bonding between the electrodes.

[0051] The working principle of the present invention is that the sensing electrodes of the jigsaw-like multi-level alternating interlocking structure perform interlocking at the interface through the piezoresistive synergistic enhancement effect. When subjected to external stress, the primary bionic micro-jigsaw structures are mechanically engaged at the interface, which can contribute excellent resistance response effects at different scales. The extremely high degree of fit will have stronger interface stability than traditional structures. When the stress is concentrated on the secondary ultra-thin and ultra-fine porous structure from the outside to the inside, it will form a predictable transmission and expansion along the ultra-thin and ultra-fine skeleton. The adaptive porous structure compensates for the stroke difference through reversible compression and recovery to avoid structural hardening, and uses the advantages of ultra-sensitive perception and ultra-wide response structure to jointly resolve the contradiction between device sensitivity and response range that is difficult to achieve at the same time.

[0052] The contents explained in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

Claims

1. A jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode, characterized in that: It comprises a flexible substrate 1, a circular electrode element 2, a rectangular electrode element 3, a packaging layer 4, and a copper-plated circuit 5; the circular electrode element and the rectangular electrode element are composed of a primary bionic interlocking micro-puzzle structure and a secondary ultra-thin and ultra-fine porous structure, the primary structure is used for mechanical meshing between the upper and lower layers of the electrode element to achieve interface interlocking, the secondary structure is used for reversible reconstruction to avoid structural hardening, and an alternating arrangement is used for silicone packaging; the manufacturing method of the bionic interlocking micro-puzzle structure sensing electrode comprises the following steps: S1 Laser Etching-Induced Front-end Process: Bionic design is performed based on the jigsaw puzzle structure, and then ultraviolet pulse laser is used for etching and removal, and infrared pulse laser is used for continuous induced growth; S2 silicone casting-transfer back-end process: liquid silicone is used for casting, vacuum heating and curing, and then silicone encapsulation is performed after transfer.

2. The jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode and its manufacturing method according to claim 1, characterized in that: The S1 laser etching-induced front-end process comprises the following steps: S101 Bionic Design: Linear regression method is used to normalize the jigsaw puzzle structure parameters and then pattern design is performed; S102 laser etching: using ultraviolet nanosecond pulsed laser, controlling the laser power to 1.0-3.0W and the scanning rate to 50-100mm / s, to etch a concave primary bionic micro-jigsaw structure on the surface of the polyimide film; S103 laser induction: Using an infrared continuous CO2 laser, under the processing parameters of laser power of 0.5-2.0W and scanning rate of 20-100mm / s, a secondary porous structure with ultra-thin pore size / extremely fine pore wall is induced to grow on the concave primary bionic micro-jigsaw structure.

3. The jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode and its manufacturing method according to claim 1, characterized in that: The S2 silica gel casting-transfer back-end process includes the following steps: S201 liquid casting: The AB components of Ecoflex liquid silicone are prepared in a mass ratio of 1:1 and cast on the primary bionic interlocking micro-jigsaw structure of the electrode. After the filling is complete, pressurization is performed to allow the silicone to fully penetrate into the secondary ultra-thin and ultra-fine porous structure; S202 curing transfer: vacuum heating treatment is used, the pressure is set to -1.5MPa, the pressurization time is 30min, the temperature is set to 80℃, and the heating time is 3h to completely solidify the liquid silicone. After cooling, the transfer mold is removed, and the silicone material is peeled off from the polyimide film to construct a jigsaw puzzle-like multi-level alternating interlocking structure; S203 silicone encapsulation: Cut the silicone film according to the electrode shape, apply conductive silver paste and heat it at 120℃, use copper foil to lead out the wires on the two electrodes, and fit the package to reserve gaps.

4. The jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode and its manufacturing method according to claim 1, characterized in that: The size of the primary bionic interlocking micro-jigsaw structure is between 50 and 100 μm, the size of the pores of the secondary ultra-thin and ultra-fine porous structure is between 3 and 5 μm, and the size of the pore wall is between 20 and 40 nm.

5. The jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode and its manufacturing method according to claim 2, characterized in that: The S102 laser etching step utilizes the principle of ultraviolet photochemistry to remove materials and weaken the carbonization effect by vaporizing molecular chains; the S103 laser induction step utilizes the principle of infrared photothermal to induce the growth of materials and strengthen the carbonization effect by ablating molecular chains.

6. The jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode and the manufacturing method thereof according to claim 3, characterized in that: The S202 curing transfer step is to invert and transplant the concave micro-puzzle template onto the surface of the silicone elastomer to construct a primary bionic micro-puzzle structure with raised surface, while retaining the secondary ultra-thin and ultra-fine porous structure inside.

7. The jigsaw puzzle-like multi-level alternating interlocking structure sensing electrode and the manufacturing method thereof according to claim 1, characterized in that: The circular electrode element 2 and the rectangular electrode element 3 are interlocked at the interface by means of alternate jigsaw puzzle-like meshing, wherein the primary bionic micro-jigsaw structures are mechanically meshed with each other, and the secondary ultra-thin and ultra-fine porous structures are reversibly resilient with each other.

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