Built-in cylindrical flexible LED array device for optical medical treatment and preparation method of built-in cylindrical flexible LED array device

Abstract

The invention relates to the technical field of optical medical treatment, and particularly provides a built-in cylindrical flexible LED array device for optical medical treatment and a preparation method thereof, and the device comprises an LED light-emitting unit, a flexible electrode, a cylindrical flexible polymer substrate and a packaging layer. Wherein the LED light-emitting units with different light-emitting wavelengths are arranged on the surface of the flexible polymer substrate in an array manner and are connected into the flexible electrode to form a light-emitting array, so that multi-wavelength adjustability of the device is realized; a micro-channel is arranged in the flexible polymer substrate, and the flexible electrode is filled in the micro-channel to realize high tensile strength of the whole device; a light diffusion agent is mixed in the packaging layer so as to improve the light emitting uniformity of the device; in the preparation method, the flexible polymer substrate is prepared by adopting a sacrificial male mold method, the problem of low preparation success rate caused by bonding the flexible substrate is avoided, and the preparation method has the advantages of simplicity and low cost.

Description

Technical Field

[0001] This invention relates to the field of photomedicine technology, specifically providing a built-in cylindrical flexible LED array device for photomedicine and its fabrication method. Background Art

[0002] Phototherapy uses light sources of specific wavelengths to irradiate the body, achieving the effects of disease prevention and treatment, and promoting collective recovery. Current phototherapy light sources mainly use lasers and LEDs. Lasers, as the light source, have advantages such as long lifespan and high light output power. Flexible light-emitting devices further reduce LEDs to micron-level size and integrate them into an array to achieve multi-wavelength tunable and highly uniform irradiation. Simultaneously, they utilize biocompatible, flexible, and stretchable biocompatible substrate materials as flexible substrates to meet the application requirements of implantable and wearable phototherapy scenarios. Regarding the stretchable electrodes of flexible light-emitting devices, the main solutions include liquid metals, conductive polymers, and irregularly shaped metal electrodes, which, combined with flexible substrates and light-emitting units, realize flexible and stretchable light-emitting devices.

[0003] Most existing built-in reproductive health phototherapy devices use rigid, cylindrical light-emitting units arranged in corresponding cylindrical shapes on the device surface. Due to the size of the cavity, existing phototherapy devices typically only allow the LED light source to be placed at the tip of the treatment head, resulting in low irradiation uniformity and the inability to simultaneously irradiate the inner wall of the cavity. For phototherapy applications in similar scenarios, a high-density, three-dimensional arrangement of light-emitting units on the substrate surface is required to achieve uniform multi-wavelength irradiation. Existing flexible and stretchable light-emitting devices often use conductive materials such as Au and Cu to create metal electrodes with special geometric shapes like serpentine, mesh, and arched shapes to achieve stretchability. However, these special shapes excessively occupy space, hindering high-density integration of light-emitting units. Methods using metal nanoparticles or nanowires as conductive electrodes have also been explored, but these methods are complex to manufacture, have low conductivity, and their resistance is greatly affected by deformation, making them unsuitable for built-in phototherapy applications. Summary of the Invention

[0004] In view of this, the present invention aims to provide a built-in cylindrical flexible LED array device for phototherapy and its fabrication method. The device uses LEDs of different wavelengths as light-emitting units and arranges them in an array to achieve multi-wavelength tunability. A cylindrical flexible polymer is used as the substrate, and flexible electrodes are used to connect and power the LED light-emitting units, achieving high stretchability of the overall device. A light-diffusing agent is coated on the surface of the device to improve the uniformity of light emission. Furthermore, the fabrication method of the built-in cylindrical flexible LED array device provided by the present invention uses a sacrificial anode method to prepare the flexible polymer substrate and injects liquid metal as a flexible electrode into the microchannel. This method achieves high stretchability while being simple and low-cost.

[0005] To achieve the above objectives, the technical solution created by this invention is implemented as follows: An embedded flexible LED array device for phototherapy includes LED light-emitting units, flexible electrodes, a flexible polymer substrate, and an encapsulation layer. The number of LED light-emitting units is not less than two, and all LED light-emitting units have different emission wavelengths. All LED light-emitting units are arrayed on the surface of the flexible polymer substrate. The flexible polymer substrate has a columnar structure, and microchannels are arranged on its surface, with electrode holes corresponding to each LED light-emitting unit formed in the microchannels. The flexible electrodes are filled in the microchannels and connected to an external driving circuit via wires. The pins of each LED light-emitting unit are inserted into the flexible electrodes through the electrode holes. The encapsulation layer is a base material mixed with a light diffusing agent and is placed on the surface of the LED light-emitting units and the flexible polymer substrate.

[0006] Furthermore, the microchannels are arranged horizontally and vertically on the surface of the flexible polymer substrate, so that the flexible electrodes are distributed on the surface of the flexible polymer substrate along the circumferential and axial directions, and the microchannels along the circumferential direction of the flexible polymer substrate are not connected to the microchannels along the axial direction of the flexible polymer substrate.

[0007] Furthermore, the diameter of the microchannels ranges from 50 μm to 1000 μm.

[0008] Furthermore, each LED light-emitting unit is a square LED light source, and the size of each LED light source is 50μm-1000μm; the positive electrode of each LED light source is connected to a flexible electrode along the circumference of the flexible polymer substrate, and the negative electrode of each LED light source is connected to a flexible electrode along the axial direction of the flexible polymer substrate.

[0009] A method for fabricating a built-in cylindrical flexible LED array device, used to prepare the built-in flexible LED array device for phototherapy provided by the present invention, specifically includes the following steps: S1: Prepare a hollow cylindrical sacrificial anode according to the arrangement of LED light-emitting units and the position of electrode holes; S2: Inject uncured flexible polymer material into the sacrificial male mold, and perform degassing and curing treatment on the uncured flexible polymer material to obtain a columnar flexible polymer substrate; S3: Immerse the flexible polymer substrate containing the sacrificial anode obtained in step S2 in a solvent to dissolve the sacrificial anode, leaving microchannels and electrode holes on the surface of the flexible polymer substrate. S4: Fill the microchannel with liquid metal to form a flexible electrode, and connect the wire to the flexible electrode; S5: Insert the pins of the LED light-emitting unit into the flexible electrode through the electrode hole to form an electrical connection between the LED light-emitting unit and the flexible electrode; S6: Coat the surface of the LED light-emitting unit and the flexible polymer substrate with the uncured substrate material mixed with light diffusing agent. After the substrate material cures and forms an encapsulation layer, the fabrication of the built-in cylindrical flexible LED array device is completed.

[0010] Furthermore, the refractive index of the light diffusing agent is different from that of the substrate material, and the particle size of the light diffusing agent is 1μm-5μm.

[0011] Compared with the prior art, the present invention can achieve the following beneficial effects: (1) The built-in cylindrical flexible LED array device for phototherapy created by the present invention has microchannels filled with flexible electrodes on the surface of the cylindrical flexible polymer substrate, thereby achieving the overall biocompatibility, flexibility and stretchability and miniaturization of the device; using LEDs of different wavelengths as light-emitting units to achieve multi-wavelength tunability of the device; and coating the surface of the device with a light-diffusing agent to improve the uniformity of light emission of the device. (2) The method for preparing the built-in cylindrical flexible LED array device described in this invention uses the sacrificial positive mold method to prepare the cylindrical flexible polymer substrate, which does not require bonding of the flexible substrate, thus improving the success rate of microchannel fabrication. The overall fabrication method has the advantages of being simple and low-cost. Attached Figure Description

[0012] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of the structure of the built-in cylindrical flexible LED array device for phototherapy as described in an embodiment of the present invention; Figure 2 A flowchart illustrating the fabrication method of the built-in cylindrical flexible LED array device described in the embodiments of the present invention; Figure 3 A schematic diagram illustrating the fabrication process of the built-in cylindrical flexible LED array device described in this embodiment of the invention.

[0013] Explanation of reference numerals in the attached figures: 1. LED light-emitting unit; 2. Flexible polymer substrate; 3. Flexible electrode; 4. Encapsulation layer; 5. Wire; 6. Sacrificial male mold. DETAILED DESCRIPTION

[0014] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0015] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0016] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0017] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0018] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] like Figure 1 As shown, the built-in flexible LED array device for photomedicine includes an LED light-emitting unit 1, a flexible polymer substrate 2, a flexible electrode 3, and an encapsulation layer 4.

[0020] The number of LED light-emitting units 1 is not less than two, and the emission wavelengths of all LED light-emitting units 1 are not all the same. The LED light-emitting units 1 include, but are not limited to, using micro LED light sources, mini LED light sources, and other forms of LED light sources such as LEDs combined with quantum dots. The shape and size of the LED light-emitting units 1 are set according to actual needs. In one embodiment, square LED light-emitting units 1 with a size of 50μm-1000μm are preferred.

[0021] All LED light-emitting units 1 are arranged in an array on the surface of a flexible polymer substrate 2. Microchannels are arranged on the surface of the flexible polymer substrate 2, and electrode holes corresponding to each LED light-emitting unit 1 are formed in the microchannels. Flexible electrodes 3 are filled in the microchannels and connected to an external driving circuit through wires 5. The pins of each LED light-emitting unit 1 are inserted into the flexible electrodes 3 through the electrode holes.

[0022] The arrangement and diameter of the microchannels on the surface of the flexible polymer substrate 2 can be adjusted according to actual needs, including but not limited to serpentine and horizontal / vertical arrangements. In one specific embodiment, to match the array form and size of the LED light-emitting units 1, the diameter of the microchannels is 50μm-1000μm, and the microchannels are arranged horizontally and vertically on the surface of the flexible polymer substrate 2, so that the flexible electrodes 3 are distributed on the surface of the flexible polymer substrate 2 along the circumference and axial direction, and the microchannels along the circumference of the flexible polymer substrate 2 are not connected to the microchannels along the axial direction. The positive electrode of each LED light-emitting unit 1 is connected to the flexible electrode 3 along the circumference of the flexible polymer substrate 2, and the negative electrode of each LED light-emitting unit 1 is connected to the flexible electrode 3 along the axial direction of the flexible polymer substrate 2. At the end of the flexible electrode 3, a metal wire is used as a conductor 5 to connect to the external driving circuit, so that the external driving circuit can control each LED light-emitting unit 1 individually.

[0023] Encapsulation layer 4 is placed on the surface of LED light-emitting unit 1 and flexible polymer substrate 2 to encapsulate the overall built-in flexible LED array device. Encapsulation layer 4 is a substrate material mixed with a light diffusing agent, which enables high uniformity illumination at close range.

[0024] like Figures 2 to 3 As shown, a method for fabricating a built-in cylindrical flexible LED array device, used to prepare the built-in flexible LED array device for phototherapy provided by this invention, specifically includes the following steps: S1: Prepare a hollow columnar sacrificial anode 6 according to the arrangement of LED light-emitting units 1 and the position of electrode holes.

[0025] The arrangement of LED light-emitting units 1 is designed based on their driving method. A sacrificial male mold 6 is then fabricated using 3D printing technology, based on this arrangement. The sacrificial male mold 6 is made of a soluble material, including but not limited to paraffin wax and other soluble materials with melting points lower than the flexible polymer material. The melting temperature of the sacrificial male mold 6 will not alter the properties of the flexible polymer material. Preferably, ABS material (acrylonitrile (A)-butadiene (B)-styrene (S) terpolymer) is used to prepare the sacrificial male mold 6, and the positions of the microchannels and electrode holes are printed simultaneously. To ensure that the resulting built-in cylindrical flexible LED array device can be smoothly inserted into the human body, a slightly curved recess is formed on the inner bottom surface of the sacrificial male mold 6. The curvature of the recess is designed and adjusted according to the actual situation.

[0026] S2: Inject uncured flexible polymer material into the sacrificial male mold 6, and perform degassing and curing treatment on the uncured flexible polymer material to obtain columnar flexible polymer substrate 2.

[0027] The flexible polymer materials include, but are not limited to, PDMS (polydimethylsiloxane), silicone, and other biocompatible materials. In one specific embodiment, PDMS material is selected.

[0028] S3: Immerse the flexible polymer substrate 2 containing the sacrificial anode 6 obtained in step S2 in a solvent to dissolve the sacrificial anode 6, so that microchannels and electrode holes on the microchannels are left on the flexible polymer substrate 2.

[0029] In this embodiment, the solvent does not alter the properties of the flexible polymer material. Specifically, an organic solvent such as acetone is used to dissolve the sacrificial anode 6, leaving microchannels with diameters of 50μm-1000μm and electrode holes on the flexible polymer substrate 2. Furthermore, the top of the flexible polymer substrate 2 has a certain degree of curvature.

[0030] S4: Fill the microchannel with liquid metal to form a flexible electrode 3, and connect the wire 5 to the flexible electrode 3.

[0031] In one specific embodiment, the liquid metal is a gallium-based liquid metal material, such as eutectic gallium indium (EGaIn) or gallium indium tin (Galinstan). The injection method of the liquid metal includes, but is not limited to, injecting the liquid metal into the microchannel using a syringe, or dripping the liquid metal into the inlet of the microchannel, placing it in a vacuum chamber and evacuating the vacuum chamber to fill the microchannel with liquid metal.

[0032] S5: Insert the pins of the LED light-emitting unit 1 into the flexible electrode 3 through the electrode hole, so that the LED light-emitting unit 1 and the flexible electrode 3 form an electrical connection.

[0033] S6: Apply uncured substrate material mixed with light diffusing agent to the surface of LED light-emitting unit and flexible polymer substrate 2. After the substrate material cures to form encapsulation layer 4, the fabrication of built-in cylindrical flexible LED array device is completed.

[0034] In one specific embodiment, the curvature of the top of the encapsulation layer 4 is consistent with the curvature of the top of the flexible polymer substrate 2. The light diffusing agent itself is a type of microsphere. To achieve certain diffusion characteristics after being mixed into the substrate material, a refractive index difference needs to be generated at the interface between the substrate and the microspheres to achieve a uniform light effect. The light diffusing agent can be any material capable of producing a light scattering effect. Preferably, a light diffusing agent with a refractive index different from that of the substrate material is used, and the particle size of the microparticles in the light diffusing agent is 1μm-5μm.

[0035] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0036] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A built-in cylindrical flexible LED array device for phototherapy, characterized in that: The device includes LED light-emitting units, flexible electrodes, a flexible polymer substrate, and an encapsulation layer. The number of LED light-emitting units is not less than two, and all LED light-emitting units have different emission wavelengths. All LED light-emitting units are arrayed on the surface of the flexible polymer substrate. The flexible polymer substrate has a columnar structure, and microchannels are arranged on its surface, with electrode holes corresponding to each LED light-emitting unit formed in the microchannels. The flexible electrodes fill the microchannels and are connected to an external driving circuit via wires. The pins of each LED light-emitting unit are inserted into the flexible electrodes through the electrode holes. The encapsulation layer is a base material mixed with a light-diffusing agent and is placed on the surface of the LED light-emitting units and the flexible polymer substrate.

2. The built-in cylindrical flexible LED array device for phototherapy according to claim 1, characterized in that: The microchannels are arranged horizontally and vertically on the surface of the flexible polymer substrate, so that the flexible electrodes are distributed on the surface of the flexible polymer substrate along the circumference and axial direction, and the microchannels along the circumference of the flexible polymer substrate are not connected to the microchannels along the axial direction of the flexible polymer substrate.

3. The built-in cylindrical flexible LED array device for phototherapy according to claim 2, characterized in that: The diameter of the microchannel is 50μm-1000μm.

4. The built-in cylindrical flexible LED array device for phototherapy according to claim 2, characterized in that: Each LED light-emitting unit is a square LED light source, and the size of each LED light source is 50μm-1000μm; the positive electrode of each LED light source is connected to a flexible electrode along the circumference of the flexible polymer substrate, and the negative electrode of each LED light source is connected to a flexible electrode along the axial direction of the flexible polymer substrate.

5. A method for fabricating a built-in cylindrical flexible LED array device, used to fabricate the built-in cylindrical flexible LED array device for phototherapy as described in any one of claims 1-4, characterized in that: Specifically, the following steps are included: S1: Prepare a hollow columnar sacrificial anode according to the arrangement of the LED light-emitting units and the position of the electrode holes; S2: Inject uncured flexible polymer material into the sacrificial male mold, and perform degassing and curing treatment on the uncured flexible polymer material to obtain a columnar flexible polymer substrate. S3: The flexible polymer substrate containing the sacrificial male mold obtained in step S2 is immersed in a solvent to dissolve the sacrificial male mold, so that the surface of the flexible polymer substrate retains the microchannels and the electrode holes; S4: Fill the microchannel with liquid metal to form the flexible electrode, and connect the wire to the flexible electrode; S5: Insert the pins of the LED light-emitting unit into the flexible electrode through the electrode hole, so that the LED light-emitting unit and the flexible electrode are electrically connected; S6: Coat the surface of the LED light-emitting unit and the flexible polymer substrate with the uncured substrate material mixed with the light diffusing agent. After the substrate material is cured and the encapsulation layer is formed, the fabrication of the built-in cylindrical flexible LED array device is completed.

6. The method for fabricating the built-in cylindrical flexible LED array device according to claim 5, characterized in that: The refractive index of the light diffusing agent is different from that of the substrate material, and the particle size of the light diffusing agent is 1μm-5μm.

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