Laser fusion manufacturing of textile hybrid electronic integrated systems

Abstract

The present invention discloses a fabric hybrid electronic integrated system manufactured by laser fusion. The system includes patch components, laser-induced flexible sensors, a fabric substrate, conductive fabric wires and physiological electrodes, and vertical interconnected vias. Through the laser's ability to modify materials, patterned sensors can be realized on the fabric substrate; through the laser's fine cutting ability, patterned flexible electrodes and interconnected wires can be realized; and by impregnating the intrinsic structure of the fabric with a conductive composite, highly stable vertical interconnected vias are realized. Combining the above-mentioned preparation technologies, a double-layer fabric circuit board can be realized on a variety of daily fabrics and special fabrics, and then the patch-type electronic devices are welded to form a fabric hybrid electronic integrated system. The present invention realizes the heterogeneous integration of rigid electronic devices, flexible electronic devices and fabrics, does not contain commercial PCB boards, FPCB boards or middleware, and is a wearable system that is fully functional, 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 our daily lives. Fabric-based electronic systems effectively combine the information processing advantages of electronic devices with the inherent strengths of fabrics. These systems empower breathable, protective, and skin-friendly fabrics with sensing, actuation, communication, and computing capabilities, bringing people closer to flexible electronic systems. These systems hold broad application prospects in precision medicine, human-computer interaction, and other fields.

[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 the commercial substrate 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 ability 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 addresses the problem of integrated integration of existing textile electronic systems and rigid components. Using laser fusion manufacturing technology as a tool and combining it with process improvements such as transfer printing, an integrated heterogeneous integration system is created that includes functionalized textiles, flexible electronic components, silicon-based chips, double-layer conductive textile lines, and vertical interconnected vias. 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 existing electronic textile technology, the present invention forms independently wired circuits on the front and back sides of the textile, significantly improving the circuit integration and applicability. It can be applied to conventional surface mount packaging chips, and the wires can be soldered, making it more applicable. Summary of the Invention

[0006] The present invention aims to address the shortcomings of existing technologies by providing a laser-fusion fabric hybrid electronic integrated system. This system utilizes the thermal effects of a CO2 laser or continuous laser to modify the fabric surface, forming a laser-induced flexible sensor with sensing capabilities. Simultaneously, the fine cutting capabilities of a pulsed laser are utilized to form patterned conductive fabric threads and physiological electrodes on a fabric substrate. This method combines multiple laser manufacturing technologies with other manufacturing technologies to achieve the integrated integration of electronic components and fabrics. The manufacturing method proposed in this invention integrates functional fabrics, flexible electronic components, rigid electronic components, and double-layer conductive fabric threads onto fabrics. The resulting fabric hybrid electronic system not only performs multiple functions such as sensing and signal transmission, but also exhibits stable performance that is 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 includes a fabric substrate, conductive fabric threads 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, interconnected to realize the overall circuit function. Its preparation specifically includes the following:

[0009] 1) Forming a laser-induced flexible sensor: Using the photothermal effect of a CO2 laser or 532nm continuous green light, the fabric substrate or the precursor material on its surface is treated according to a pre-designed pattern to induce reactions such as carbonization, phase separation, or reduction sintering. This generates a laser-induced flexible sensor on one side of the fabric substrate for detecting physical and chemical signals on the body surface, and the sensor is then led out from the other side of the fabric substrate.

[0010] 2) Forming vertical interconnect vias: Where vias are needed to connect the circuits on both sides of the fabric substrate, a conductive paste is infiltrated into the fabric substrate's texture structure using pneumatic injection, allowing the corresponding areas of the fabric substrate to connect on both sides.

[0011] 3) Forming conductive fabric threads and physiological electrodes: Using an ultraviolet nanosecond laser to cut the conductive fabric according to a pre-designed pattern to form conductive fabric threads and physiological electrodes, and then transferring the conductive fabric threads and physiological electrodes to both sides of the fabric substrate using a transfer method. The conductive fabric threads and physiological electrodes on both sides are connected through the vertical interconnected vias;

[0012] 4) Integrated chip components: Use low-melting-point solder paste to solder chip 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):polyphenylenesulfonate (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 and 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 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 thread and 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, adhering the entire AL / MT / SL to a fabric base with the AL surface, and then immersing it in water. After the SL layer softens in the water, it is removed, the AL / MT layer attached to the fabric base is dried, and the excess AL / MT layer except for the patterned conductive circuit is peeled off to form a conductive fabric thread or physiological electrode.

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

[0019] Implementing a dual-layer conductive circuit with independent routing on a single piece of fabric allows for a more integrated circuit layout. This also isolates rigid electronic components from the skin-friendly flexible electronic components on the front and back of the fabric, ensuring wearer comfort. This approach has enabled the acquisition and wireless transmission of multiple physiological signals on a single piece of fabric, which has been validated in human motion experiments. 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 textile line and a double-layer conductive textile 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 fabric hybrid electronic integrated system manufactured for this process collected ECG signals after being rubbed by hand for 20 seconds (bottom) and before rubbing (top).

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

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

[0029] The technical solution of the invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0030] According to a specific embodiment of the present invention, a textile hybrid electronic integrated system manufactured by laser fusion specifically includes:

[0031] (1) Laser-induced graphene (LIG) sensor fabrication:

[0032] 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 a photothermal reaction, thereby obtaining a patterned LIG sensor that is sensitive to the temperature and strain of the body surface.

[0033] A CO2 laser was used to irradiate the connection of the LIG sensor from the other side of the PI fabric substrate, allowing the LIG to penetrate the thickness of the PI fabric, thereby allowing the LIG sensor to be extracted from the other side of the PI fabric.

[0034] (2) Vertical Interconnect Vias (VIAs) Manufacturing:

[0035] Liquid metal (LM) and copper nanoparticles (Cu NPs) are first mixed in a centrifugal mixer to form a LM / Cu NP slurry with good wettability. This slurry is then printed on predetermined locations on both sides of a PI fabric substrate.

[0036] 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, thereby making the LM / Cu NPs on both sides of the PI fabric conductive in the vertical direction, thus obtaining LM / Cu NP VIAs.

[0037] (3) Fabrication of double-layer conductive fabric lines and physiological electrodes by combining laser cutting and transfer printing:

[0038] A laser-perforated adhesive film (AL) is attached to a metallized textile (MT) to create an AL / MT fabric. A water-soluble adhesive sacrificial layer (SL) is then attached to the MT side of the AL / MT fabric to create an AL / MT / SL fabric. A UV nanosecond laser is then used to cut the AL / MT / SL fabric from the AL side. The laser spot follows the contours of the conductive textile and the physiological electrode. The laser energy penetrates the AL and MT, but not the SL.

[0039] The AL side of the AL / MT / SL is then attached to the PI fabric substrate, forming the PI / AL / MT / SL. The PI / AL / MT / SL is then soaked in water to decompose the SL, resulting in the PI / AL / MT. After drying the PI / AL / MT, the excess AL / MT is peeled off along the laser-cut lines, resulting in a conductive fabric thread and physiological electrode adhered to the PI fabric. Heat pressing the PI / AL / MT further enhances the AL's adhesion.

[0040] Repeating the above steps on the other side of the PI fabric substrate creates a double layer of conductive fabric. The PI fabric substrate electrically insulates the conductive fabrics of the different layers, leaving only the LM / Cu NP VIAs.

[0041] (4) Integration of general-purpose chip components:

[0042] After the above operations, a patterned conductive fabric thread and physiological electrodes were formed on the PI fabric surface. Solder paste and aluminum flux were then mixed in a 5:1 volume ratio to create a mixed slurry with a low melting point that could remove the oxide layer on the conductive fabric thread surface. This mixed slurry was then used to solder surface-mounted devices (SMDs) onto the conductive fabric thread.

[0043] The fabric hybrid electronic integrated system produced by the present invention maintains normal operation even after washing and rubbing, and the integration of electronic components and the fabric substrate is highly reliable. Furthermore, a double-layer conductive circuit with independent wiring is implemented on a single layer of fabric, enabling universal circuit functionality on a breathable fabric substrate. This system can wirelessly monitor heart rate, respiration, and electrocardiogram signals without the need for additional commercial circuit boards and wiring. Key technical features include:

[0044] (1) Combine laser cutting with transfer printing to prevent the overflow of laser energy from damaging the fabric base. 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 printing method is not used and the uncut conductive fabric is attached to the fabric base for laser cutting, the overflowing laser energy will act on the fabric base, destroying its structural integrity and aesthetics. If the transfer printing method is used, then during laser cutting, the conductive fabric is underneath a sacrificial layer, not a fabric base, so the overflowing laser energy will not act on the fabric base. After 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 base, the sacrificial layer can be dissolved by cold water, so the conditions are mild and will not damage the fabric base and the conductive medium.

[0045] (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, slurry-like physical properties, overcomes the high surface tension of common LMs such as eutectic gallium indium and gallium indium tin, and is easy to apply to rough fabric surfaces. 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 NPs is uneven. Acid treatment will cause a certain degree of damage to Cu NPs, and the dosage is difficult to control. Alkali treatment, such as soaking in NaOH solution, will leave NaOH in the slurry that is difficult to remove. The present invention uses the tangential force generated during the centrifugal process to destroy the oxide film on the surface of LM, so that LM and Cu NPs react fully 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.

[0046] (3) Soldering is performed using a mixture of solder paste and aluminum flux. The outermost layer of commercial conductive fabrics is mostly nickel, and its oxide layer is difficult to remove with conventional flux in solder paste. Using aluminum flux can remove the nickel oxide layer, allowing the conductive fabric to 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 the solder paste in one step, reducing the number of steps.

[0047] Specifically:

[0048] like Figure 1 As shown, to fabricate the LIG sensor, a CO2 laser (wavelength 10.6 μm, spot radius 76 μm) was first used to machine the front surface 111 of the PI fabric substrate, forming patterned LIG sensors 131 and positioning holes (approximately 600 μm in diameter). After coating the LIG sensor with Ecoflex 00-50, a CO2 laser was then used to machine LIG extraction points 132 on the back surface 112 of the PI fabric substrate where the LIG sensor 131 overlapped. This created a LIG conductive pathway 133 that penetrated the fabric in the cross-section 113 of the PI fabric substrate, ultimately allowing the LIG sensor to be extracted from the other side 112 of the PI fabric substrate.

[0049] like Figure 2 As shown, to fabricate VIAs, liquid metal EGaIn and Cu NPs are first mixed in a high-speed defoamer at a mass ratio of 50:1 to synthesize a LM / Cu NP slurry. The LM / Cu NP slurry is then printed onto the target location using a polyethylene terephthalate (PET) mask 21 and a brush. An air blow gun (3 mm outlet diameter, 200 kPa pressure) is then used to blow air onto one side of the LM / Cu NP slurry 221. The PI fabric substrate is flipped over, and the same blowing operation is repeated onto the other side of the LM / Cu NP slurry 222. Finally, a LM / Cu NP VIA 223 is formed where the LM / Cu NP slurries 221 and 222 overlap.

[0050] like Figure 3 As shown in the figure, a single-layer conductive fabric and a double-layer conductive fabric with four LM / Cu NP VIAs were subjected to repeated bending experiments. The upper figure shows the resistance change of the single-layer conductive fabric under repeated bending, while the lower figure shows the resistance change of the double-layer conductive fabric with four LM / Cu NP VIAs under repeated bending. It can be seen that both conductors exhibit similar anti-interference performance, indicating that the LM / Cu NP VIAs do not affect the basic functionality of the textile circuit.

[0051] like Figure 4 As shown in Figures a, b, c, and d, the lit 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 figure a as an example, LEDs are welded to 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 LEDs are 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.

[0052] like Figure 5 As shown, to create a double-layer conductive fabric, a layer of adhesive film (AL) 53 is applied to one side of a metal fabric (MT) 51, and a sticky water-soluble sacrificial layer (SL) 52 is applied to the other side. A UV nanosecond laser 54 (355nm wavelength, 16μm spot radius) is then used to cut the metal fabric (MT) 61 and the adhesive film (AL) 53 into a patterned conductive circuit. The underlying water-soluble sacrificial layer (SL) 52 remains intact, temporarily securing the conductive circuit. A conceptual enlarged view of the cut section is shown in the circular box in the upper right corner of the figure.

[0053] like Figure 6 As shown, the AL / MT / SL is bonded to a fabric substrate 61, then immersed in water. The SL film 62 softens and can be removed. The remaining AL / MT layer attached to the fabric substrate is then dried, and the excess AL / MT 631 is peeled off, leaving behind the patterned AL / MT 632, which serves as a conductive fabric thread or physiological electrode. By repeating the same process on the other side of the fabric substrate 61, a circuit is obtained on both sides. The circuits on both sides are connected by LM / Cu NP VIAs 64, creating a vertically interconnected double-layer fabric circuit. Finally, both sides of the double-layer fabric circuit are heat-pressed at 80°C to strengthen the adhesion between the conductive fabric thread, electrode, and fabric substrate.

[0054] like Figure 7 As shown in the figure, 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 components on the fabric are not affected, which shows that the fabric hybrid electronic system has good bending resistance.

[0055] like Figure 8 To further verify the stability of the fabric hybrid electronic integrated system, the fabric was rubbed for approximately 20 seconds and then used to collect ECG signals. 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 identical, demonstrating the considerable durability of the fabric hybrid electronic integrated system.

[0056] like Figure 9 To further verify the washability of the fabric hybrid electronic integrated system, the fabric was soaked in detergent and then hand-washed and ultrasonically cleaned. The top image shows the fabric before cleaning, and the bottom image shows the fabric after cleaning. It can be seen that the stains and residual solder on the fabric are removed after cleaning, while the Bluetooth module can still communicate with the mobile phone, facilitating the long-term maintenance of the fabric hybrid electronic integrated system.

[0057] like Figure 10As shown in the figure, a LIG sensor, physiological electrodes, a double-layer conductive fabric thread, and a rigid silicon-based chip were integrated onto a single piece of fabric using a laser fusion manufacturing process. To verify the signal acquisition and transmission capabilities of this fabric hybrid electronic integrated system, the fabric was placed in a suitable position near the left chest of a subject, who then performed an indoor cycling exercise. During exercise, the fabric hybrid electronic integrated system was able to simultaneously collect three physiological signals: heart rate, respiration, and electrocardiogram (ECG), and wirelessly transmit them to a host computer for data visualization and real-time processing.

Claims

1. A textile hybrid electronic integrated system manufactured by laser fusion, characterized in that: The device comprises a fabric substrate, conductive fabric lines and physiological electrodes, vertical interconnected vias, laser-induced flexible sensors, and patch components. The fabric substrate is one or more of modal knitted fabric, medical nonwoven fabric, polyimide PI fabric, or polyester taffeta fabric. All electronic components are tightly integrated on a fabric substrate and distributed on both sides of the fabric substrate, connected to realize the overall circuit function. The preparation thereof 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, 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 interconnect vias: Where vias are needed on the fabric substrate to connect the circuits on both sides, a conductive paste is infiltrated into the fabric substrate's textured structure using a pneumatic perfusion method, allowing the corresponding areas of the fabric substrate to connect on both sides. The conductive paste is an intermetallic compound (LM / Cu NP) paste formed by mixing liquid metal and copper nanoparticles using a centrifugal mixer. 3) Forming conductive fabric threads and physiological electrodes: Using a laser to cut the conductive fabric according to a pre-designed pattern to form conductive fabric threads and physiological electrodes, and then using a transfer method to transfer the conductive fabric threads and physiological electrodes to both sides of the fabric substrate, the conductive fabric threads and physiological electrodes on both sides are connected through the vertical interconnection vias; 4) Integrated chip components: Use low-melting-point solder paste to solder chip 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, characterized in that: The formation of the laser-induced flexible sensor is specifically as follows: using the photothermal effect of a CO2 laser or continuous green light with a wavelength of 532 nm, the precursor material on the fabric substrate or its surface is processed according to a pre-designed pattern to induce carbonization, phase separation or reduction sintering reaction, and 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.

3. The textile hybrid electronic integrated system manufactured by laser fusion according to claim 1, characterized in that: The conductive fabric thread and physiological electrode are prepared by combining 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. After cutting, the conductive fabric thread and the physiological electrode are transferred to a fabric substrate. Finally, the sacrificial layer is dissolved with water to prevent the laser from damaging the fabric substrate.

4. The textile hybrid electronic integrated system manufactured by laser fusion according to claim 3, characterized in that: The preparation method of the conductive fabric thread and physiological electrode specifically includes: pressing a layer of adhesive film AL on one side of a metal fabric MT, and pressing a layer of adhesive 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. After the SL layer softens in the water, it is removed; 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 thread or physiological electrode.

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

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