Hybrid electronic integrated system for manufacturing fabric through laser fusion

Abstract

The invention discloses a fabric mixing electronic integration system manufactured through laser fusion. The system comprises a patch type component, a laser-induced flexible sensor, a fabric substrate, a conductive fabric line, a physiological electrode and a vertical interconnection via hole. A patterned sensor can be realized on a fabric substrate through the modification capability of laser on a material; a patterned flexible electrode and an interconnection wire are realized through the fine cutting capability of laser; the intrinsic structure of the fabric is infiltrated with the conductive compound, so that high-stability vertical interconnection via holes are realized. By integrating the preparation technology, a double-layer fabric circuit board can be realized on various daily fabrics and special fabrics, and then a fabric hybrid electronic integrated system is formed after surface-mounted electronic devices are welded. Heterogeneous integration of the rigid electronic device, the flexible electronic device and the fabric is achieved, commercial PCBs or FPCBs or middleware is not included, and the wearable system is complete in function, breathable and compatible with body surface mechanics.

Description

Technical Field

[0001] The present invention belongs to the technical field of wearable electronics and relates to an intelligent electronic fabric, and in particular to a fabric hybrid electronic integrated system manufactured by laser fusion. Background Art

[0002] Fabrics are the most intimate objects in people's daily lives. Fabric-based electronic systems can effectively combine the information processing advantages of electronic devices and the intrinsic advantages of fabrics, giving breathable, protective, and skin-friendly fabrics the ability to sense, drive, communicate, and calculate, bringing people closer to flexible electronic systems, and have broad application prospects in the fields of precision medicine, human-computer interaction, and so on.

[0003] According to the integration method of silicon-based electronic devices, there are three main methods to realize textile electronic systems. The first is to integrate general silicon-based chips on commercial substrates other than fabrics, and only retain intrinsically flexible devices on the fabric. This solution cannot overcome the mechanical incompatibility between commercial substrates and the human body surface, and it is difficult to ensure wearing comfort. The second is to abandon silicon-based chips and use functionalized fibers to weave electronic devices. This all-fiber electronic fabric exhibits the capabilities of signal processing, visual interaction, and wireless transmission, but there are difficulties in functional versatility and interface versatility. The third is to integrate silicon-based chips on a fabric substrate. This method is more direct and flexible, and gives full play to the advantages of silicon-based electronic devices, but its functional density, wearing comfort, and installation tightness need to be improved.

[0004] The present invention aims at the problem of integrated integration of existing textile electronic systems and rigid components. By using laser fusion manufacturing technology as a tool and combining process improvements such as transfer printing, an integrated heterogeneous integration system including functionalized textiles, flexible electronic components, silicon-based chips, double-layer conductive textile lines and vertical interconnected vias is created. This system can realize universal circuit functions on a single piece of textile, thereby improving the portability and functional density of textile electronic systems.

[0005] Compared with the existing electronic textile technology, the present invention forms independently wired circuits on the front and back sides of the textile, which significantly improves the circuit integration and application scope. It can be applied to conventional surface mount packaging chips, and the wires can be soldered, which has a wider applicability. Summary of the invention

[0006] The purpose of the present invention is to provide a laser fusion fabric hybrid electronic integrated system to address the deficiencies of the prior art, using the thermal effect of CO2 laser or continuous laser to modify the fabric surface to form a laser-induced flexible sensor with sensing function, and at the same time using the fine cutting ability of pulsed laser to form patterned conductive fabric lines and physiological electrodes on the fabric substrate, combining multiple laser manufacturing technologies with other manufacturing technologies to achieve integrated integration of electronic components and fabrics. The manufacturing method proposed in the present invention can integrate functional fabrics, flexible electronic components, rigid electronic components, and double-layer conductive fabric lines on fabrics, and the resulting fabric hybrid electronic system can not only realize multiple functions such as sensing detection and signal transmission, but also has stable performance of being resistant to washing and rubbing.

[0007] The technical solution adopted by the present invention to solve the above technical problems is:

[0008] A fabric hybrid electronic integrated system manufactured by laser fusion, including a fabric substrate, conductive fabric wires and physiological electrodes, vertical interconnected vias, laser-induced flexible sensors and patch components. All electronic components are tightly integrated on a fabric substrate and distributed on both sides of the fabric substrate to realize the overall circuit function. The preparation thereof specifically includes the following:

[0009] 1) Forming a laser-induced flexible sensor: using the photothermal effect of CO2 laser or 532nm wavelength continuous green light, the precursor material on the fabric substrate or its surface is treated according to a pre-designed pattern to induce carbonization, phase separation or reduction sintering and other reactions, so that a laser-induced flexible sensor is generated on one side of the fabric substrate to detect physical and chemical signals on the body surface, and the sensor is led out from the other side of the fabric substrate;

[0010] 2) Forming vertical interconnection vias: At the location where vias need to be formed on the fabric substrate to connect the circuits on both sides, the conductive paste is infiltrated into the texture structure of the fabric substrate at that location by using the air pressure perfusion method, so that the corresponding area of ​​the fabric substrate is connected on the front and back sides;

[0011] 3) forming conductive fabric lines and physiological electrodes: using ultraviolet nanosecond laser to cut the conductive fabric according to a pre-designed pattern to form conductive fabric lines and physiological electrodes, and then transferring the conductive fabric lines and physiological electrodes to both sides of the fabric substrate by a transfer method, and the conductive fabric lines and physiological electrodes on both sides are connected through the vertical interconnection vias;

[0012] 4) Integrated SMD components: Use low melting point solder paste to solder SMD components onto the conductive fabric line to form a complete circuit.

[0013] Furthermore, the fabric substrate is one or more of modal knitted fabric, medical nonwoven fabric, polyimide PI fabric or polyester taffeta fabric.

[0014] Furthermore, the formation of the laser induced flexible sensor is specifically as follows: using a CO2 laser to carbonize one side of the fabric substrate according to a pre-designed pattern to generate a laser induced graphene sensor; or using a 532nm wavelength continuous green light to induce a phase separation reaction of poly(3,4-ethylenedioxythiophene):polybenzenesulfonate (PEDOT:PSS) on the fabric surface to generate a laser induced PEDOT:PSS sensor; or using a 532nm wavelength continuous green light to induce a reduction sintering reaction of silver nano-ink on the fabric surface to generate a laser induced metal sensor, and the above sensors are led out from the other side of the fabric substrate.

[0015] Furthermore, the conductive paste is an intermetallic compound LM / Cu NP paste formed by mixing liquid metal and copper nanoparticles using a centrifugal mixer or a high-speed defoaming machine.

[0016] Furthermore, the preparation of the conductive fabric thread and the physiological electrode is a combination of laser cutting of the conductive fabric and transfer method: during laser cutting, a water-soluble sacrificial layer is used to temporarily fix the conductive fabric thread and the physiological electrode, and after cutting is completed, the conductive fabric thread and the physiological electrode are transferred to the fabric base, and finally the sacrificial layer is dissolved with water to avoid damage to the fabric base caused by the laser.

[0017] Furthermore, the preparation method of the conductive fabric line and the physiological electrode specifically includes: pressing a layer of adhesive film (AL) on one side of a metal fabric (MT), and pressing a layer of water-soluble sacrificial layer (SL) on the other side of the metal fabric to form an AL / MT / SL structure, using an ultraviolet nanosecond laser to cut a patterned conductive circuit from the AL and MT layers, while keeping the SL intact, attaching the entire AL / MT / SL to a fabric base with the AL surface, and then immersing it in water, removing the SL layer after it softens in water, drying the AL / MT layer attached to the fabric base, and peeling off the excess AL / MT layer except for the patterned conductive circuit to form a conductive fabric line or a physiological electrode.

[0018] Furthermore, the low melting point solder paste is a mixed paste of solder paste and aluminum flux. The advantages of the present invention are:

[0019] The double-layer conductive circuit with independent wiring on a single piece of fabric allows for a higher integration of circuit layouts, and isolates rigid electronic components and skin-friendly flexible electronic components on the front and back of the fabric, ensuring comfort when wearing it. Based on this, the collection and wireless transmission of multiple physiological signals on a single piece of fabric was achieved, which was verified in human body experiments during exercise. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the fabrication of laser-induced graphene sensors.

[0021] Figure 2 Schematic diagram of the fabrication of LM / Cu NP VIAs.

[0022] Figure 3 Resistance changes of a single-layer conductive fabric line and a double-layer conductive fabric line with four LM / Cu NP VIAs under repeated bending.

[0023] Figure 4 Images of LM / Cu NP VIAs fabricated on various everyday textiles and lighting up LEDs.

[0024] Figure 5 , Figure 6 Schematic diagram of the fabrication of a double-layer conductive fabric line.

[0025] Figure 7 Image of the textile hybrid electronic integrated system fabricated for this process in a bent state.

[0026] Figure 8 The ECG signals collected by the fabric hybrid electronic integrated system manufactured for this process after being rubbed by hand for 20 seconds (below) and before rubbing (above).

[0027] Fig. 9 Images of the fabric hybrid electronics integrated system built for the process before (top) and after (bottom) cleaning.

[0028] Fig.10 Photographs of the multifunctional wireless textile sensing patch fabricated for the process (left), its placement on the human body (center), and its signal visualization interface (right). Specific implementation methods

[0030] The technical solution of the invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0031] According to a specific embodiment of the present invention, a textile hybrid electronic integrated system manufactured by laser fusion specifically includes:

[0032] (1) Laser-induced graphene (LIG) sensor fabrication:

[0033] Polyimide (PI) fabric was selected as the substrate, and a CO2 laser was used to irradiate the PI textile. PI was converted into LIG through photothermal reaction, thereby obtaining a patterned LIG sensor that is sensitive to the temperature and strain of the body surface.

[0034] A CO2 laser was used to irradiate the connection of the LIG sensor from the other side of the PI fabric substrate, so that the LIG penetrated the thickness of the PI fabric, thereby allowing the LIG sensor to be led out from the other side of the PI fabric.

[0035] (2) Vertical Interconnect Vias (VIAs) Manufacturing:

[0036] First, liquid metal (LM) and copper nanoparticles (Cu NP) are mixed by a centrifugal mixer to form LM / Cu NP slurry with good wettability, and then the slurry is printed on the predetermined positions on both sides of the PI fabric substrate.

[0037] An air gun was used to blow air on the LM / Cu NP slurry on both sides to make it penetrate into the pores of the PI fabric, so that the LM / Cu NPs on both sides of the PI fabric were connected in the vertical direction, thereby obtaining LM / Cu NP VIAs.

[0038] (3) Fabrication of double-layer conductive fabric lines and physiological electrodes by combining laser cutting and transfer printing:

[0039] A laser-perforated adhesive film (AL) is attached to a metallized textile (MT) to obtain AL / MT. Then, a sticky water-soluble sacrificial layer (SL) is attached to the MT side of AL / MT to obtain AL / MT / SL. Then, an ultraviolet nanosecond laser is used to cut AL / MT / SL from the AL side, during which the laser spot moves along the outer contour of the conductive fabric line and the physiological electrode. The laser energy causes the AL and MT to be cut through, but the SL is not cut through.

[0040] The AL side of the AL / MT / SL is then attached to the PI fabric substrate to form PI / AL / MT / SL. The PI / AL / MT / SL is then soaked in water to decompose the SL to obtain PI / AL / MT. After drying the PI / AL / MT, the excess AL / MT is peeled off along the contour line cut by the laser to obtain the conductive fabric line and physiological electrode adhered to the PI fabric. The PI / AL / MT is hot pressed to further enhance the adhesion of the AL.

[0041] Repeat the above operation on the other side of the PI fabric substrate to obtain a double-layer conductive fabric line. The PI fabric substrate electrically insulates the conductive fabric lines of different layers, and only the LM / Cu NP VIAs are connected.

[0042] (4) Integration of general-purpose SMD components:

[0043] After the above operations, patterned conductive fabric lines and physiological electrodes were obtained on the surface of the PI fabric. The solder paste and aluminum flux were stirred and mixed in a volume ratio of 5:1 to obtain a mixed slurry with a low melting point and capable of removing the oxide layer on the surface of the conductive fabric line. The mixed slurry was used to solder the SMD component (SMD) on the conductive fabric line.

[0044] The fabric hybrid electronic integrated system made by the technical solution of the present invention can still work normally after washing and rubbing, and the integration reliability of electronic components and fabric substrate is high. In addition, a double-layer conductive circuit with independent wiring is realized on a single-layer fabric, so that universal circuit functions can be realized on a breathable fabric substrate, and wireless monitoring of three signals of heart rate, breathing, and electrocardiogram can be realized without the need for additional commercial circuit boards and drag wires. Several key technical points are:

[0045] (1) Combine laser cutting with the transfer method to prevent the overflow of laser energy from damaging the fabric substrate. In order to ensure that the excess conductive fabric can be removed smoothly along the laser cut, a slightly larger laser energy is often required. If the transfer method is not used and the uncut conductive fabric is attached to the fabric substrate for laser cutting, the overflowing laser energy will act on the fabric substrate, destroying its structural integrity and aesthetics. If the transfer method is used, then during laser cutting, the conductive fabric is underneath a sacrificial layer, not a fabric substrate, so the overflowing laser energy will not act on the fabric substrate. When the cutting is completed, the conductive fabric line and the physiological electrode are spatially discontinuous, and their relative positions are fixed by the sacrificial layer. After they are transferred to the fabric substrate, the sacrificial layer can be dissolved by cold water, so the conditions are mild and will not damage the fabric substrate and the conductive medium.

[0046] (2) The tangential force provided by the centrifugal mixer is used to promote the preparation of LM / Cu NP slurry. The intermetallic compound formed by the reaction of gallium-based liquid metal and other metal nanoparticles has semi-solid and slurry-like physical properties, overcomes the high surface tension of common LM such as eutectic gallium indium and gallium indium tin, and is easy to be coated on the rough fabric surface. This intermetallic compound is usually prepared by manual crushing, acid treatment or alkali treatment. Manual crushing is inefficient and the dispersion of LM and Cu NP is uneven. Acid treatment will cause a certain degree of damage to Cu NP, and the dosage is difficult to control. Alkali treatment, such as soaking in NaOH solution, will leave difficult-to-remove NaOH in the slurry. The present invention uses the tangential force generated during the centrifugation process to destroy the oxide film on the surface of LM, so that LM and Cu NP fully react during the mixing process, without the introduction of additional chemical reagents, the mixing effect is uniform, and only one step is required. The final LM / Cu NP has a certain fluidity and can penetrate into the pores of the fabric by air pressure infusion to form LM / Cu NP VIAs.

[0047] (3) Use a mixed paste of solder paste and aluminum flux for soldering. The outermost layer of commercial conductive fabrics is mostly metal nickel, and its oxide layer is difficult to remove with conventional flux in solder paste. Using aluminum flux can remove the nickel oxide layer, so that the conductive fabric can be subsequently soldered with solder paste. Mixing solder paste and aluminum flux together can achieve the removal of the nickel oxide layer and soldering of solder paste in one step, reducing the number of steps.

[0048] Specific:

[0049] like Figure 1 As shown, in order to manufacture the LIG sensor, the front side 111 of the PI fabric substrate is first processed using a CO2 laser 12 (wavelength 10.6 μm, spot radius 76 μm) to form a patterned LIG sensor 131 and a positioning hole (diameter of about 600 μm). After the LIG sensor is coated with Ecoflex 00-50, a CO2 laser 12 is used to process a LIG lead-out point 132 in the overlapping area of ​​the back side 112 of the PI fabric substrate and the LIG sensor 131, so that a LIG conductive path 133 penetrating the fabric is formed in the cross section 113 of the PI fabric substrate, and finally the LIG sensor is led out from the other side 112 of the PI fabric substrate.

[0050] like Figure 2 As shown, in order to manufacture VIAs, liquid metal EGaIn and Cu NP are first mixed in a high-speed defoamer at a mass ratio of 50:1 to synthesize LM / Cu NP slurry. Then, the LM / Cu NP slurry is printed to the target position using a polyethylene terephthalate (PET) mask 21 and a brush, and an air blow gun (outlet diameter 3 mm, pressure 200 kPa) is used to blow air on one side of the LM / Cu NP slurry 221. The PI fabric substrate is turned over, and the same blowing operation is performed on the other side of the LM / Cu NP slurry 222. Finally, a LM / Cu NP VIA 223 is formed at the position where the LM / CuNP slurry 221 and the LM / CuNP slurry 222 overlap.

[0051] like Figure 3 As shown in the figure, a single-layer conductive fabric line and a double-layer conductive fabric line with four LM / Cu NP VIAs were subjected to repeated bending experiments. The upper figure shows the change in resistance of the single-layer conductive fabric line under repeated bending, and the lower figure shows the change in resistance of the double-layer conductive fabric line with four LM / Cu NP VIAs under repeated bending. It can be seen that the two wires show similar anti-interference performance, indicating that LM / Cu NP VIAs do not affect the basic functions of the fabric circuit.

[0052] like Figure 4 As shown in a, b, c, and d, the lighted LED and LM / Cu NP VIAs are connected in series on modal knitted fabric, medical nonwoven fabric, PI fabric, and polyester taffeta woven fabric, respectively. Figure 4 Taking a as an example, the LED is welded at electrodes 41 and 42, and electrodes 42 and 43 are connected to the circuit on the back of the fabric through two LM / Cu NP VIAs. When power is applied to electrodes 41 and 43, the LED is lit, indicating that the proposed LM / Cu NP VIAs can meet the design requirements of complex fabric circuits and realize cross-layer transmission of physiological signals.

[0053] like Figure 5 As shown, in order to manufacture a double-layer conductive fabric line, a layer of adhesive film (AL) 53 is pressed on one side of a metal fabric (MT) 51, and a layer of adhesive water-soluble sacrificial layer (SL) 52 is pressed on the other side of the metal fabric 51. Then, an ultraviolet nanosecond laser 54 (wavelength 355nm, spot radius 16μm) is used to cut the metal fabric (MT) 61 and the adhesive film (AL) 53 into a patterned conductive circuit, while the water-soluble sacrificial layer (SL) 52 underneath remains intact, which temporarily fixes the conductive circuit. The circular frame in the upper right corner of the figure is a partial enlarged conceptual diagram of the cutting part.

[0054] like Figure 6 As shown, the above AL / MT / SL is attached to the fabric substrate 61, and then the whole is immersed in water, in which the SL film 62 can be removed after softening. Then the remaining AL / MT layer attached to the fabric substrate is dried, and the excess AL / MT 631 is peeled off, leaving the patterned AL / MT 632 as a conductive fabric line or physiological electrode. By repeating the same operation on the other side of the fabric substrate 61, the circuit on both sides can be obtained. The circuits on both sides are connected by LM / Cu NP VIAs 64, thereby realizing a double-layer fabric circuit interconnected in the vertical direction. Finally, the two sides of the double-layer fabric circuit are hot-pressed at 80°C to strengthen the adhesion between the conductive fabric line, the electrode and the fabric substrate.

[0055] like Figure 7 As shown, in order to verify the bending resistance of the fabric hybrid electronic system, the fabric is bent to a curvature radius of 25 mm, while the patch elements on the fabric are not affected, which indicates that the fabric hybrid electronic system has good bending resistance.

[0056] like Figure 8 As shown in the figure, in order to further verify the stability of the fabric hybrid electronic integrated system, the fabric was rubbed by hand for about 20 seconds, and then the ECG signal was collected. The upper figure shows the signal collected before rubbing, and the lower figure shows the signal collected after rubbing. It can be seen that the ECG signals collected by the system before and after rubbing are almost the same, which shows that the fabric hybrid electronic integrated system has considerable durability.

[0057] like Fig. 9 As shown, in order to further verify the washability of the fabric hybrid electronic integrated system, the fabric was soaked in detergent and hand-washed and ultrasonically cleaned. The upper picture shows the fabric before cleaning, and the lower picture shows the fabric after cleaning. It can be seen that the stains and residual solder on the fabric are removed after cleaning, and the Bluetooth module can still communicate with the mobile phone, which is convenient for the long-term maintenance of the fabric hybrid electronic integrated system.

[0058] like Fig.10As shown in the figure, the LIG sensor, physiological electrodes, double-layer conductive fabric wire, and rigid silicon-based chip are integrated on a single piece of fabric using a laser fusion manufacturing process. In order to verify the signal acquisition and transmission function of the fabric hybrid electronic integrated system, the fabric is placed at a suitable position near the left chest of the experimenter, and the experimenter is asked to perform indoor cycling exercises. During exercise, the fabric hybrid electronic integrated system can simultaneously collect three physiological signals: heart rate, respiration, and electrocardiogram, and wirelessly transmit them to the host computer for data visualization and real-time processing.

Claims

1. A fabric hybrid electronic integrated system manufactured by laser fusion, characterized in that: It includes a fabric substrate, conductive fabric lines and physiological electrodes, vertical interconnected vias, laser-induced flexible sensors and patch components. All electronic components are tightly integrated on a fabric substrate and distributed on both sides of the fabric substrate to achieve the overall circuit function. Its preparation specifically includes the following: 1) Forming a laser-induced flexible sensor: using a laser to modify the fabric substrate or a precursor material on its surface according to a pre-designed pattern, so that a laser-induced flexible sensor is generated on one side of the fabric substrate for detecting physical and chemical signals on the body surface, and the sensor is led out from the other side of the fabric substrate; 2) Forming vertical interconnection vias: At the location where vias need to be formed on the fabric substrate to connect the circuits on both sides, the conductive paste is infiltrated into the texture structure of the fabric substrate at that location by using the air pressure perfusion method, so that the corresponding area of ​​the fabric substrate is connected on the front and back sides; 3) forming conductive fabric lines and physiological electrodes: using a laser to cut the conductive fabric according to a pre-designed pattern to form conductive fabric lines and physiological electrodes, and then transferring the conductive fabric lines and physiological electrodes to both sides of the fabric substrate by a transfer method, and the conductive fabric lines and physiological electrodes on both sides are connected through the vertical interconnection vias; 4) Integrated SMD components: Use low melting point solder paste to solder SMD components onto the conductive fabric line to form a complete circuit.

2. The textile hybrid electronic integrated system manufactured by laser fusion according to claim 1 is characterized in that: The fabric substrate is one or more of modal knitted fabric, medical nonwoven fabric, polyimide PI fabric or polyester taffeta fabric.

3. The textile hybrid electronic integrated system manufactured by laser fusion according to claim 1 is characterized in that: The formation of the laser induced flexible sensor is specifically as follows: utilizing the photothermal effect of CO2 laser or 532nm continuous green light, processing the precursor material on the fabric substrate or its surface according to a pre-designed pattern, inducing carbonization, phase separation or reduction sintering reaction, generating a laser induced flexible sensor on one side of the fabric substrate for detecting physical and chemical signals on the body surface, and leading the sensor out from the other side of the fabric substrate.

4. The textile hybrid electronic integrated system manufactured by laser fusion according to claim 1 is characterized in that: The conductive paste is an intermetallic compound LM / Cu NP paste formed by mixing liquid metal and copper nanoparticles using a centrifugal mixer.

5. The textile hybrid electronic integrated system manufactured by laser fusion according to claim 1 is characterized in that: The preparation of the conductive fabric thread and the physiological electrode is to combine laser cutting of the conductive fabric and a transfer method: during laser cutting, a water-soluble sacrificial layer is used to temporarily fix the conductive fabric thread and the physiological electrode, and after cutting is completed, the conductive fabric thread and the physiological electrode are transferred to a fabric substrate, and finally the sacrificial layer is dissolved with water to avoid damage to the fabric substrate caused by the laser.

6. The textile hybrid electronic integrated system manufactured by laser fusion according to claim 5 is characterized in that: The preparation method of the conductive fabric line and the physiological electrode specifically includes: pressing a layer of adhesive film (AL) on one side of a metal fabric (MT), and pressing a layer of sticky water-soluble sacrificial layer (SL) on the other side of the metal fabric to form an AL / MT / SL structure, using an ultraviolet nanosecond laser to cut a patterned conductive circuit from the AL and MT layers, while keeping the SL intact, attaching the entire AL / MT / SL to a fabric base with the AL surface, and then immersing it in water, removing the SL layer after it softens in the water, drying the AL / MT layer attached to the fabric base, and peeling off the excess AL / MT layer except for the patterned conductive circuit to form a conductive fabric line or a physiological electrode.

7. The textile hybrid electronic integrated system manufactured by laser fusion according to claim 1 is characterized in that: The low melting point solder paste is a mixed slurry of tin paste and aluminum soldering flux.

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