A flexible phototherapy device and method of manufacture

Abstract

The application discloses a flexible phototherapy instrument, which comprises a flexible substrate, a conductive coating, a multi-wavelength LED array and a vacuum packaging layer; wherein the flexible substrate comprises a skin contact layer, an inner layer intermediate functional layer and an outer surface protective layer from bottom to top in sequence, the upper surface of the intermediate functional layer is upwardly convex to form a cylindrical rigid island; the conductive coating is arranged on the upper surface of the intermediate functional layer and covers the rigid island and a wave conductor; and the multi-wavelength LED array is flip-chip bonded on the top surface of the rigid island. The flexible phototherapy instrument adopts a flexible substrate as a basic structure, the skin contact inner layer, the intermediate functional layer and the outer surface protective layer arranged from bottom to top all have good flexibility, can be flexibly bent along the curved contour of different parts of the human body, avoids the gap problem caused by the fact that the existing rigid substrate phototherapy instrument cannot be attached to the curved surface, ensures that the phototherapy instrument is in close contact with the skin, reduces light energy leakage, and makes the light uniformly act on the treatment area.

Description

Technical Field

[0001] This invention relates to the field of medical and health care instruments, and in particular to a flexible phototherapy device and its preparation method. Background Technology

[0002] With the continuous development of medical technology, phototherapy has become increasingly widely used in the treatment of skin diseases, wound healing promotion, and beauty care due to its advantages such as being non-invasive, having few side effects, and being easy to operate. Among the core components of phototherapy, LEDs (light-emitting diodes) occupy an important position due to their superior performance. LEDs can efficiently convert electrical energy into light energy, with an energy conversion efficiency far exceeding that of traditional light sources. They also possess numerous advantages such as small size, long lifespan, low power consumption, high brightness, and ease of integration. This has led to their widespread application in various fields of modern society, including lighting, flat panel displays, and medical devices, and in particular, they have provided key technological support for the research and development and promotion of wearable phototherapy devices.

[0003] In the field of phototherapy, wearable LED phototherapy devices have gradually become the focus of market attention due to their ability to allow users to conveniently receive phototherapy during daily activities. However, most wearable LED phototherapy devices currently on the market are in the form of small household appliances. Their core structure is usually based on a rigid substrate design, which makes the device difficult to bend and adapt to the curved contours of different parts of the body (such as joints, neck, face, etc.). This structural defect directly results in poor fit between the phototherapy device and the skin. This not only makes it easy for gaps to appear during use, causing some light energy to leak and affecting the uniformity of the phototherapy effect, but also causes discomfort due to poor fit, reducing the user experience and even limiting the application scenarios of the phototherapy device on specific body parts.

[0004] In addition, most existing wearable LED phototherapy devices use rigid PCBs or FPCs as LED carriers. Although FPCs are flexible, their copper foil-polyimide composite structure is prone to fatigue fracture when repeatedly bent or subjected to large local deformation, resulting in open circuits and dead LEDs. Furthermore, the elastic modulus of FPC substrates is much higher than that of skin, causing the edges to lift up when worn, resulting in poor fit and easy displacement of the treatment area, which affects the treatment. Summary of the Invention

[0005] The technical problem solved by this invention is to provide a flexible phototherapy device and its preparation method.

[0006] This application provides a flexible phototherapy device, comprising, The flexible substrate comprises, from bottom to top, a skin-contact inner layer, an intermediate functional layer, and an outer protective layer. The skin-contact inner layer has multiple breathable micropores evenly distributed on it. The upper surface of the intermediate functional layer protrudes upward to form a cylindrical rigid island. The top surface of the outer protective layer, located above the rigid island, is etched with blind holes. The intermediate functional layer is provided with wavy guide wires, both ends of which are tangent to the rigid island. A conductive coating is applied to the upper surface of the intermediate functional layer and covers the rigid island and the wavy conductor. A multi-wavelength LED array is flip-chip welded to the top surface of the rigid island, with the emitting surface facing upwards; A vacuum sealing layer is disposed on the flexible substrate, covering all functional layers on the top and bottom and forming a waterproof skirt around the perimeter.

[0007] Furthermore, the multi-wavelength LED array is provided with multiple quantum dot color mixing microlayers, which respectively cover the chips of the same physical array. Pixel-level wavelength conversion is achieved through micro-spray printing, so that the same physical array can output arbitrary peak wavelengths of 400-1100 nm.

[0008] Furthermore, a self-healing protective film is sprayed onto the upper surface of the conductive coating. A self-healing ring is provided on the self-healing protective film and located on the outer ring of the rigid island. The self-healing ring is coaxial with the rigid island. Multiple sawtooth-shaped cracks are opened along the circumference of the self-healing ring. The cracks are filled with self-healing capsules. The material of the self-healing protective film is medical self-healing polyurethane varnish, and the material of the self-healing capsule is sesame oil-PU capsule.

[0009] Furthermore, a flexible MCU and a constant current drive IC are arranged side by side on the conductive coating and outside the self-healing ring, and the ACF adhesive at the bottom of the flexible MCU and the constant current drive IC is pressed against the bus of the conductive coating.

[0010] Furthermore, a heating film is provided in the lateral gap of each chip in the multi-wavelength LED array. The heating film is made of conductive silver paste-carbon nanotube composite-polyester elastomer. The flexible MCU, constant current drive IC, and multi-wavelength LED array constitute the device area. Microcurrent electrode pairs are symmetrically arranged on both sides of the device area, which extend in a finger-like shape to form a current loop that runs through the treatment area.

[0011] Furthermore, the bottom end face of the inner skin contact layer is provided with a living layer, which is alternately arranged with the heating film for secreting therapeutic proteins after blue light activation.

[0012] Furthermore, the living layer includes a biodegradable light gate layer, a microcage-hydrogel microfiber layer disposed on the lower surface of the biodegradable light gate layer, and an engineered bacterial layer disposed within the microcage-hydrogel microfiber layer. The microcage-hydrogel microfiber layer is made of silk fibroin-graphene-agarose composite hydrogel, the biodegradable light gate layer is made of o-nitrobenzyl-polyethylene glycol film, and the strain of the engineered bacterial layer is GRAS-grade lactococcus lactis.

[0013] Furthermore, the lower surface of the rigid island is provided with mushroom-shaped micro-anchors, which are embedded in the skin-contact inner layer.

[0014] Furthermore, the outer protective layer is a TPU film, the intermediate functional layer is an epoxy-silicone rubber blend, the conductive coating is a silver nanowire mesh, on which a 20μm self-healing protective film is sprayed. When stretched by 150%, ΔR / R0 ≤ 8%. After 10 stretches, a clear varnish is sprayed to restore the self-healing property. The vacuum encapsulation layer is a TPU-silicone laminate.

[0015] This application provides a method for preparing a flexible phototherapy device, comprising the following steps: Co-extrude flexible substrates and then injection mold rigid islands; After plasma cleaning of the upper surface of the intermediate functional layer of the flexible substrate, stretchable conductive silver paste is screen-printed on the surface. It is pre-baked in an infrared tunnel oven at 80℃ for 10 min, and then baked at 110℃ for 15 min. After cooling at 25℃ for 5 min, a conductive coating is formed. A 2μm wide serrated crack is pre-formed in the same material as the stretchable conductive silver paste on the edge ring of the rigid island, and filled with linseed oil-PU microcapsules to construct a self-healing ring. Medical self-healing polyurethane varnish was sprayed onto the conductive coating and cured in an oven at 80°C for 2 hours to form a 10μm thick self-healing protective film. The chip is aligned with the top of the rigid island through the bottom electrode and flip-chip bonded to the top of the rigid island by ACF hot pressing. The chip is hot-pressed for 10 seconds at 180°C and 1MPa to construct a multi-wavelength LED array. A quantum dot mixed-color microlayer is printed on the top of the chip, with three overlapping rings (outer, middle, and inner). After curing at 80°C for 30 minutes, a software-tunable wavelength output of 400-1100 nm is achieved. Silk fibroin-agarose hydrogel coaxial 3D printing, with 5μm blind holes in the wall, GRAS grade lactococcus lactis in-line inoculation, 2μm biodegradable light shutter layer for sealing, cross-linking at 37℃ for 2h, and UV-triggered lysis for 5s; The heating film is screen-printed on the gaps between the multi-wavelength LED array, and finger electrodes are symmetrically printed on both sides of the device area; The TPU-silicone laminate was vacuum laminated at 85℃ and 1kPa for 10 minutes, with hot-pressed skirts extending 2mm beyond the substrate around the perimeter.

[0016] Compared with existing technologies, this invention uses a flexible substrate as the basic structure. The inner skin contact layer, the middle functional layer, and the outer protective layer arranged from bottom to top all have good flexibility. They can be flexibly bent to conform to the curved contours of different parts of the human body (such as joints, neck, face, etc.), avoiding the gap problem caused by the inability of existing rigid substrate phototherapy devices to fit curved surfaces. This ensures that the phototherapy device is in close contact with the skin, reduces light leakage, and allows the light to act evenly on the treatment area. In addition, the wavy wires and rigid islands printed on the same layer as the middle functional layer replace the traditional FPC. The elongation at break is ≥500%, the resistance change after 1000 150% bends is ≤5%, and the minimum bending radius is ≤5mm. It can adapt to high curvature parts such as joints and neck without re-fabricating the circuit. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention.

[0018] Figure 1 This is a schematic diagram of the flexible phototherapy device of the present invention; Figure 2 This is a partial side view of the flexible phototherapy device of the present invention; Figure 3 This is a partial top view of the conductive coating of the present invention; Figure 4 This is a partial top view of the self-healing ring of the present invention.

[0019] The reference numerals in the attached figures include: 1. Flexible substrate; 101. Inner skin contact layer; 102. Intermediate functional layer; 103. Outer protective layer; 104. Breathable micropores; 105. Rigid islands; 106. Blind holes; 2. Conductive coating; 3. Multi-wavelength LED array; 4. Vacuum encapsulation layer; 5. Quantum dot color mixing microlayer; 6. Self-healing protective film; 7. Self-healing ring; 8. Self-healing capsule; 9. Flexible MCU; 10. Constant current drive IC; 11. Heating film; 12. Microcurrent electrode pair; 13. Living layer; 131. Biodegradable light gate layer; 132. Microcage-hydrogel microfiber layer; 133. Engineered bacterial layer; 14. Mushroom-shaped micro-anchors; 15. Cracks; Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] like Figures 1-4 As shown, the flexible phototherapy device of the present invention includes a flexible substrate 1, a conductive coating 2, a multi-wavelength LED array 3, and a vacuum encapsulation layer 4; wherein the flexible substrate 1 comprises, from bottom to top, a skin contact inner layer 101 (Young's modulus 0.1-0.3 MPa, thickness 50-100 μm, for low-pressure adhesion, using medical-grade SEBS (Kraton G1645) + 5 wt% white oil), an intermediate functional layer 102 (Young's modulus 1-3 MPa, thickness 80-150 μm, with a stretchable conductive coating 2 printed on the surface to replace the traditional FPC, using EPON828 + PDMS ylgard 184, 70:30) + 30 wt% SiO2 nanopowder), and an outer protective layer 103 (Young's modulus 5-8 MPa). The inner skin contact layer 101 has multiple breathable micropores 104 evenly distributed on it. The upper surface of the intermediate functional layer 102 protrudes upward to form a cylindrical rigid island 105 (the specific location is in the orthographic projection area of ​​the corresponding electronic component, which can make the maximum strain in the component area ≤5% and the maximum strain in the adjacent non-island area ≥150%, realizing the hard area protects the component and the soft area can bend arbitrarily with the joint). The top surface of the outer protective layer 103 and above the rigid island 105 is etched with blind holes 106. The intermediate functional layer 102 is provided with a wavy guide wire, with both ends tangent to the rigid island 105. The conductive coating 2 is provided on the upper surface of the intermediate functional layer 102 and covers the rigid island 105 and the wavy guide wire. The multi-wavelength LED array 3 is flip-chip soldered to the top surface of the rigid island 105 with the light-emitting surface facing upward. The vacuum encapsulation layer 4 is provided on the flexible substrate 1 and covers all functional layers on the top and bottom and forms a waterproof skirt around the perimeter.

[0022] This invention uses a flexible substrate as its basic structure. The inner skin contact layer 101, the intermediate functional layer 102, and the outer protective layer 103 arranged from bottom to top all have good flexibility and can be flexibly bent to conform to the curved contours of different parts of the human body (such as joints, neck, face, etc.). This avoids the gap problem caused by the inability of existing rigid substrate phototherapy devices to fit curved surfaces, ensuring close contact between the phototherapy device and the skin, reducing light leakage, and allowing light to act evenly on the treatment area. In addition, the wavy wires and rigid islands 105 printed on the same layer as the intermediate functional layer 102 replace the traditional FPC. The elongation at break is ≥500%, the resistance change after 1000 150% bending is ≤5%, and the minimum bending radius is ≤5mm. It can adapt to high curvature parts such as joints and neck without re-fabricating the circuit.

[0023] Specifically, the flexible substrate 1, combined with the multiple breathable micropores 104 evenly distributed in the skin contact inner layer 101, has the following advantages: on the one hand, the flexible structure can reduce the hard friction between the phototherapy device and the skin, reducing the pressure caused by prolonged wear; on the other hand, the breathable micropores 104 can allow air circulation between the skin and the outside world, avoiding the stuffiness and dampness caused by sweat accumulation, significantly improving the comfort of wearing, and making it more suitable for users to use for a long time in daily activities.

[0024] In some embodiments, multiple quantum dot color mixing microlayers 5 (quantum dot-silicone color mixing layers) (outer / middle / inner three-ring overprinting) are provided above the multi-wavelength LED array 3, which respectively cover the chips of the same physical array. Pixel-level wavelength conversion is achieved through micro-spray printing, and the output of any peak wavelength of 400-1100nm can be achieved by adjusting the current in software. There is no need to replace the LED chips or redesign the array structure. It can meet the wavelength requirements of different scenarios such as skin disease treatment (e.g., 415 nm blue light treatment for acne), wound healing (e.g., 660 nm red light to promote cell proliferation), and deep tissue treatment (e.g., 808 nm near-infrared light to penetrate deep skin). Its adaptability and versatility far exceed those of existing fixed wavelength or limited wavelength adjustable phototherapy devices.

[0025] In this embodiment, due to the unique size quantum effect of quantum dot materials, the emission wavelength can be precisely controlled by adjusting the particle size of the quantum dots—the smaller the particle size, the shorter the emission wavelength, and vice versa. Therefore, by using micro-spray printing technology, quantum dot materials of different particle sizes are made into color-mixing microlayers, which are then used to cover the corresponding chips of the LED array. When the excitation light (such as blue light or ultraviolet light) emitted by the LED chip irradiates the quantum dot color-mixing microlayer 5, the quantum dots absorb the excitation light energy and then transition to emit light. By adjusting the composition and ratio of quantum dots in the quantum dot color-mixing microlayer 5 on different chips, the wavelength conversion of the light emitted by the LED chip can be achieved, ultimately enabling the same physical array to output light with any peak wavelength in the range of 400-1100nm. Moreover, the pixel-level coverage method of micro-spray printing ensures the accuracy of wavelength adjustment and the wavelength independence of local areas.

[0026] In some embodiments, a self-healing protective film 6 is sprayed onto the upper surface of the conductive coating 2. A self-healing ring 7 is provided on the self-healing protective film 6 and located on the outer ring of the rigid island 105. The self-healing ring 7 is coaxial with the rigid island 105. Multiple sawtooth cracks 15 are opened along the circumference of the self-healing ring 7. The cracks 15 are filled with self-healing capsules 8. The self-healing protective film 6 is made of medical self-healing polyurethane varnish. The self-healing capsule 8 is made of sesame oil-PU capsule. It provides local high-stress reinforcement, with a rupture pressure of 0.22 MPa and a resistance recovery of 98% / 0.2 s. The conductive coating 2 is a silver nanowire mesh with a 20 μm self-healing protective film 6 sprayed on it. When stretched by 150%, ΔR / R0 ≤ 8%. After 10 stretches, the self-healing property is restored by re-spraying varnish. The minimum bending radius is ≤ 5 mm, and there is no need to re-manufacture the FPC.

[0027] In this embodiment, the conductive coating 2 adopts a silver nanowire mesh structure, which has excellent conductivity and flexibility. A 20μm thick medical self-healing polyurethane varnish is sprayed onto the conductive coating 2 as a self-healing protective film 6. This serves two purposes: firstly, it isolates the conductive coating 2 from external moisture and dust, preventing oxidation of the silver nanowires or contamination by impurities that could lead to increased resistance; secondly, when the device is stretched by 150%, the resistance change rate ΔR / R0 of the conductive coating 2 is ≤8%, far lower than the resistance fluctuation of traditional conductive coating 2 after stretching, ensuring stable current transmission during flexible deformation. Furthermore... Even if the self-healing performance of the self-healing protective film 6 decreases after 10 stretches, its self-healing ability can be quickly restored by spraying medical self-healing polyurethane varnish. There is no need to replace the conductive coating 2 or the entire structure, resulting in low maintenance costs and convenient operation. At the same time, the serrated cracks 15 on the self-healing ring 7 are filled with sesame oil-PU capsules. When the self-healing ring 7 is damaged due to bending or external force, the sesame oil-PU capsules rupture, and the internal sesame oil-PU material flows out and undergoes a physical or chemical cross-linking reaction at the crack, realizing self-repair of the crack. This further ensures the structural integrity and circuit stability of the connection area between the conductive coating 2 and the rigid island 105.

[0028] In some embodiments, a flexible MCU9 and a constant current drive IC10 are arranged side by side on the conductive coating 2 and outside the self-healing ring 7. The ACF adhesive at the bottom of the flexible MCU9 and the constant current drive IC10 is pressed against the bus of the conductive coating 2. On the one hand, this avoids the compatibility problem between traditional rigid control chips and flexible substrate 1, allowing them to bend synchronously with the flexible substrate 1 without affecting the overall flexibility of the device. On the other hand, the flexible MCU9 can precisely control the output current of the constant current drive IC10, enabling the multi-wavelength LED array 3 to obtain a stable operating current, avoiding light intensity instability caused by current fluctuations, and ensuring precise and controllable phototherapy dosage. At the same time, the MCU can also control other functional components such as the heating film 11 and the living layer 13 in conjunction to achieve multi-parameter synergistic treatment.

[0029] In this embodiment, because the ACF adhesive contains conductive particles, the pins of the flexible MCU9 and the constant current drive IC10 can form a stable electrical connection with the bus of the conductive coating 2 through the pressing process. At the same time, the insulating substrate of the ACF adhesive can ensure the insulation between adjacent pins and adapt to the deformation requirements of the flexible substrate 1. Since the flexible MCU9 has the characteristics of miniaturization and low power consumption, it can receive external instructions or sensor signals (such as the temperature signal of the treatment area) through a preset program and output control signals to the constant current drive IC10. The constant current drive IC10 then adjusts the output current according to the control signal to ensure that the LED array can obtain a constant current under different working conditions, thereby ensuring stable luminous intensity. In addition, the flexibility of the MCU allows it to bend together with the substrate, avoiding the problem of pin breakage or poor contact of rigid chips during bending.

[0030] In some embodiments, a heating film 11 is provided in the lateral gap of each chip in the multi-wavelength LED array 3. The heating film 11 is made of conductive silver paste-carbon nanotube composite-polyester elastomer, which can provide a suitable temperature (such as 37-40℃ close to human body temperature) during phototherapy, promote blood circulation in the treatment area, accelerate the absorption of light energy by the skin, and enhance cell metabolic activity by increasing the temperature. It works synergistically with phototherapy to significantly improve wound healing speed and the treatment effect of skin diseases. The heating film 11 has good flexibility and conductivity and does not affect the overall bending performance of the device. The flexible MCU9, constant current drive IC10, and multi-wavelength LED array 3 constitute the device area. Microcurrent electrode pairs 12 are symmetrically arranged on both sides of the device area. They extend in a finger-like shape to form a current loop that runs through the treatment area and forms a uniform electric field that runs through the treatment area without additional stacking.

[0031] In this embodiment, the silver paste and carbon nanotubes in the conductive silver paste-carbon nanotube composite-polyester elastomer form a continuous conductive network. When current passes through, the conductive material generates heat due to the Joule effect, and the carbon nanotubes have excellent thermal conductivity, which can make the heat evenly distributed on the surface of the heating film 11, so as to achieve uniform heating of the treatment area. The polyester elastomer substrate ensures that the heating film 11 has good flexibility and tensile properties, and adapts to the bending requirements of the equipment.

[0032] In some embodiments, a living layer 13 is provided on the bottom end face of the inner skin contact layer 101. The living layer 13 is alternately arranged with the heating film 11 and is used to secrete therapeutic proteins after activation by blue light (such as 400-450nm blue light output by the multi-wavelength LED array 3). This allows for targeted treatment of specific diseases (such as inflammatory skin diseases and infected wounds), overcoming the limitations of traditional phototherapy that relies solely on light energy, and improving the specificity and effectiveness of treatment. The engineered bacterial layer 133 in the living layer 13 uses GRAS-grade (generally considered safe) Lactococcus lactis. This strain, after genetic engineering, can initiate the expression of specific genes under blue light irradiation, synthesizing and secreting proteins with specific therapeutic effects. Therapeutic proteins (such as antimicrobial peptides, anti-inflammatory factors, etc.); the biodegradable light gate layer 131 is made of o-nitrobenzyl-polyethylene glycol film. Under blue light irradiation, the o-nitrobenzyl groups undergo photolysis, causing the light gate layer to degrade and providing a release channel for the therapeutic proteins secreted by engineered bacteria; the microcage-hydrogel microfiber layer 132 (silk fibroin-graphene-agarose composite hydrogel) provides a stable growth microenvironment for engineered bacteria on the one hand, and its porous structure facilitates the penetration of therapeutic proteins into the skin treatment area on the other hand. At the same time, silk fibroin and agarose have good biocompatibility, while graphene can enhance the mechanical properties and thermal conductivity of the hydrogel, working together with the heating film 11 to maintain a suitable treatment temperature.

[0033] In some embodiments, the lower surface of the rigid island 105 is provided with mushroom-shaped micro-anchors 14, which are embedded in the skin-contact inner layer 101. The "barbed" structure of the mushroom-shaped micro-anchors 14 can significantly enhance the mechanical interlocking force between the rigid island 105 and the skin-contact inner layer 101, preventing relative displacement between the rigid island 105 and the flexible substrate 1 during equipment bending, and ensuring the stability of the LED array installation position. The outer protective layer 103 is a TPU film with good flexibility, wear resistance, and water resistance. The intermediate functional layer 102 is made of an epoxy-silicone rubber blend, which combines the high strength of epoxy resin and the high elasticity of silicone rubber, providing stable support for the wave conductor and the rigid island 105, while adapting to the bending requirements of the equipment. The vacuum encapsulation layer 4 is a TPU-silicone laminate, which is hot-pressed on both sides, with the edges extending 2mm beyond the substrate, providing IPX7 waterproof rating, and a water vapor transmission rate ≥5mg / cm. -2 .h -1 It is breathable and does not accumulate water, and the edges do not curl up.

[0034] In this embodiment, the head diameter of the mushroom-shaped micro-anchor 14 is larger than the rod diameter. After being embedded in the skin contact inner layer 101, the head can form a mechanical interlocking structure with the substrate of the skin contact inner layer 101. When the rigid island 105 is subjected to an upward or lateral pulling force, the "barb" of the head can prevent the micro-anchor from coming out of the substrate, thereby firmly fixing the rigid island 105 to the skin contact inner layer 101.

[0035] Specifically, both the conductive coating 2 and the electronic components are coated with waterproof materials, including silicone, TPU, and high thixotropic materials. The conductive coating 2 has a light source area and a charging area. The light source area is an electrolyte, which forms a battery by double electroplating the positive and negative electrodes. The battery area can be covered with a self-healing layer. The charging area is a coil drawn on the conductive coating, which is charged through the principle of electromagnetic induction.

[0036] This application provides a method for preparing a flexible phototherapy device, comprising the following steps: Co-extruded flexible substrate and injection-molded rigid islands, specifically including: a medical-grade SEBS inner layer, an epoxy-silicone rubber blend intermediate functional layer, and a medical-grade TPU outer layer co-extruded. The intermediate functional layer is formed by in-mold injection molding into a rigid cylindrical island with a diameter of 0.3 mm and a height of 60 μm, which is integrally connected with the substrate; After plasma cleaning of the upper surface of the intermediate functional layer of the flexible substrate, stretchable conductive silver paste is screen-printed on the surface. It is pre-baked in an infrared tunnel oven at 80℃ for 10 min, and then baked at 110℃ for 15 min. After cooling at 25℃ for 5 min, a conductive coating is formed. A 2μm wide serrated crack is pre-formed in the same material as the stretchable conductive silver paste on the edge ring of the rigid island, and filled with linseed oil-PU microcapsules to construct a self-healing ring. Medical self-healing polyurethane varnish was sprayed onto the conductive coating and cured in an oven at 80°C for 2 hours to form a 10μm thick self-healing protective film. A commercially available 450nm InGaN flip chip (200×200×75μm) is aligned with the top of a rigid island through the bottom electrode and flip-bonded to the top of the rigid island by ACF hot pressing. The chip is then hot-pressed at 180℃ and 1MPa for 10s to construct a multi-wavelength LED array. Micro-spray printing of CsPbX3@PMMA quantum dots-medical silicone mixed micro dots on the top of the chip, with outer / middle / inner three-ring overlay printing, single dot thickness 15μm, after curing at 80℃ for 30min, achieves software-tunable wavelength output of 400-1100nm; Medical silk fibroin-agarose hydrogel coaxial 3D printing, with 5μm blind holes in the wall, GRAS-grade lactococcus lactis online inoculation, 2μm biodegradable light shutter layer for sealing, cross-linking at 37℃ for 2h, UV-triggered lysis for 5s, forming a new functional combination of "microcage + online inoculation + UV-triggered release". A conductive silver paste-carbon nanotube composite-polyester elastomer heating film was screen-printed onto the gaps between multi-wavelength LED arrays. Liquid metal-silver nanowire electrodes were symmetrically printed on both sides of the device region, with a finger length of 5 mm and a gap of 100 μm, and a current density of 0.1-0.5 mA / cm². 2 ; The TPU-silicone laminate was vacuum laminated at 85℃ and 1kPa for 10 minutes, with hot-pressed skirts extending 2mm beyond the substrate around the perimeter.

[0037] In this embodiment, co-extrusion molding enables seamless composite of the three-layer flexible substrate structure, preventing interlayer separation; ACF hot-press flip-chip bonding ensures a strong connection between the chip and the rigid island through molecular-level bonding; vacuum lamination process ensures that the TPU-silicone encapsulation layer tightly covers all functional layers, eliminating air bubbles and gaps—this multi-level structural reinforcement design ensures that the components are not easily detached or damaged under repeated bending and stretching, significantly improving structural reliability; in addition, from the co-extrusion molding of the flexible substrate to the conductive coating and self-healing protective film prepared by stretchable conductive silver paste, and then to the flexible living layer of coaxial 3D printing, the entire process is designed with "ensuring flexibility" as the core design goal, ensuring that the final product can flexibly adapt to the curvature of the human body while taking into account structural strength; 400-1100 is achieved by micro-spray printing quantum dot mixed color microlayers. With adjustable nm wavelength, a screen-printed heating film for temperature-assisted treatment, finger electrodes for microcurrent synergy, and a coaxial 3D-printed living layer for targeted biological therapy, this fabrication method integrates four major functions—phototherapy, heating, microcurrent, and biological therapy—into a single device. Each functional module is independently controllable, allowing for flexible combinations of functions to meet diverse treatment needs, such as acne treatment, wound healing, and skin tightening. Furthermore, the living layer utilizes GRAS-grade Lactococcus lactis (a recognized safe strain), combined with a biodegradable light shutter layer and biocompatible silk fibroin-agarose hydrogel, ensuring that the engineered bacteria are released only after UV triggering and that the materials are non-irritating to the skin. The use of medical-grade self-healing polyurethane varnish further ensures the safety of the device in contact with the skin, avoiding the risk of allergies or infection, making it suitable for sensitive skin, wounds, and other special treatment scenarios.

[0038] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0039] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0040] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0041] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A flexible phototherapy device, characterized in that, include, The flexible substrate (1) includes, from bottom to top, a skin contact inner layer (101), an intermediate functional layer (102), and an outer protective layer (103). The skin contact inner layer (101) has a plurality of breathable micropores (104) evenly distributed on it. The upper surface of the intermediate functional layer (102) protrudes upward to form a cylindrical rigid island (105). The top surface of the outer protective layer (103) and above the rigid island (105) is etched with blind holes (106). The intermediate functional layer (102) is provided with a wavy guide wire, with both ends tangent to the rigid island (105). A conductive coating (2) is provided on the upper surface of the intermediate functional layer (102) and covers the rigid island (105) and the wave conductor; A multi-wavelength LED array (3) is flip-chip welded to the top surface of the rigid island (105), with the light-emitting surface facing upwards; A vacuum sealing layer (4) is disposed on the flexible substrate (1) and covers all functional layers on the top and bottom and forms a waterproof skirt around the perimeter.

2. The flexible phototherapy device as described in claim 1, characterized in that, The multi-wavelength LED array (3) is provided with multiple quantum dot color mixing micro-layers (5) above it, which cover the chips of the same physical array respectively. Pixel-level wavelength conversion is achieved by micro-spray printing, so that the same physical array can output arbitrary peak wavelengths of 400-1100 nm.

3. The flexible phototherapy device as described in claim 2, characterized in that, The upper surface of the conductive coating (2) is sprayed with a self-healing protective film (6). A self-healing ring (7) is provided on the self-healing protective film (6) and on the outer ring of the rigid island (105). The self-healing ring (7) is coaxial with the rigid island (105). Multiple sawtooth cracks (15) are opened on the self-healing ring (7) along its circumference. The cracks (15) are filled with self-healing capsules (8). The material of the self-healing protective film (6) is medical self-healing polyurethane varnish, and the material of the self-healing capsule (8) is sesame oil-PU capsule.

4. The flexible phototherapy device as described in claim 3, characterized in that, A flexible MCU (9) and a constant current drive IC (10) are arranged side by side on the conductive coating (2) and outside the self-healing ring (7). The ACF adhesive at the bottom of the flexible MCU (9) and the constant current drive IC (10) is pressed against the bus of the conductive coating (2).

5. The flexible phototherapy device as described in claim 4, characterized in that, A heating film (11) is provided in the lateral gap of each chip in the multi-wavelength LED array (3). The heating film (11) is made of conductive silver paste-carbon nanotube composite-polyester elastomer. The flexible MCU (9), constant current drive IC (10), and multi-wavelength LED array (3) form the device area. Microcurrent electrode pairs (12) are symmetrically arranged on both sides of the device area. They extend in a finger-like shape to form a current loop that runs through the treatment area.

6. The flexible phototherapy device as described in claim 5, characterized in that, The bottom end face of the inner skin contact layer (101) is provided with a living layer (13), which is staggered with the heating film (11) for secreting therapeutic proteins after blue light activation.

7. The flexible phototherapy device as described in claim 6, characterized in that, The living layer (13) includes a biodegradable shutter layer (131), a microcage-hydrogel microfiber layer (132) disposed on the lower surface of the biodegradable shutter layer (131), and an engineered bacterial layer (133) disposed within the microcage-hydrogel microfiber layer (132). The microcage-hydrogel microfiber layer (132) is made of silk fibroin-graphene-agarose composite hydrogel, the biodegradable shutter layer (131) is made of o-nitrobenzyl-polyethylene glycol film, and the strain of the engineered bacterial layer (133) is GRAS-grade lactococcus lactis.

8. The flexible phototherapy device as described in claim 7, characterized in that, The lower surface of the rigid island (105) is provided with mushroom-shaped micro-anchors (14), which are embedded in the skin contact inner layer (101).

9. The flexible phototherapy device as described in claim 8, characterized in that, The outer protective layer (103) is a TPU film, the intermediate functional layer (102) is an epoxy-silicone rubber blend, the conductive coating (2) is made of stretchable conductive silver paste, a 20μm self-healing protective film (6) is sprayed on it, 100% stretching cycle 1000 times ΔR / R0≤8%, and the vacuum encapsulation layer (4) is a TPU-silicone laminate.

10. The method for preparing the flexible phototherapy device according to any one of claims 1 to 9, characterized in that, Includes the following steps: Co-extrude flexible substrates and then injection mold rigid islands; After plasma cleaning of the upper surface of the intermediate functional layer of the flexible substrate, stretchable conductive silver paste is screen-printed on the surface. It is pre-baked in an infrared tunnel oven at 80℃ for 10 min, and then baked at 110℃ for 15 min. After cooling at 25℃ for 5 min, a conductive coating is formed. A 2μm wide serrated crack is pre-formed in the same material as the stretchable conductive silver paste on the edge ring of the rigid island, and filled with linseed oil-PU microcapsules to construct a self-healing ring. Medical self-healing polyurethane varnish was sprayed onto the conductive coating and cured in an oven at 80°C for 2 hours to form a 10μm thick self-healing protective film. The chip is aligned with the top of the rigid island through the bottom electrode and flip-chip bonded to the top of the rigid island by ACF hot pressing. The chip is hot-pressed for 10 seconds at 180°C and 1MPa to construct a multi-wavelength LED array. A quantum dot mixed-color microlayer is printed on the top of the chip, with three overlapping rings (outer, middle, and inner). After curing at 80°C for 30 minutes, a software-tunable wavelength output of 400-1100 nm is achieved. Silk fibroin-agarose hydrogel coaxial 3D printing, with 5μm blind holes in the wall, GRAS grade lactococcus lactis in-line inoculation, 2μm biodegradable light shutter layer for sealing, cross-linking at 37℃ for 2h, and UV-triggered lysis for 5s; The heating film is screen-printed on the gaps between the multi-wavelength LED array, and finger electrodes are symmetrically printed on both sides of the device area; The TPU-silicone laminate was vacuum laminated at 85℃ and 1kPa for 10 minutes, with hot-pressed skirts extending 2mm beyond the substrate around the perimeter.

Images