Textile-based near-infrared OLED, and hair loss care device using same

Abstract

The present invention provides a top-emitting OLED hair loss care device designed on a textile-based substrate. Furthermore, the OLED hair loss care device according to the present invention implements a near-infrared OLED. Near-infrared rays are effective in stimulating cellular activity in hair follicles due to the ability of such rays to penetrate deep into biological tissues. However, if heat generation caused by the emission of near-infrared rays is not controlled, there is a risk of degradation in the performance of the substrate. However, by implementing a top-emitting near-infrared OLED, the present invention has the advantage of being able to control light energy so that optimal light energy suitable for enhancing cell activity can be effectively transmitted to cells. Therefore, the textile-based near-infrared OLED according to the present invention is expected to be widely used for hair loss treatment as well as medical devices for various purposes.

Description

Textile-based near-infrared OLED, and hair loss care device using the same

[0001] The present invention relates to a top-emitting near-infrared OLED designed on a textile-based substrate, and a device for preventing or treating hair loss using the same.

[0002] Hair loss is a condition affecting millions of people worldwide; according to a survey by the National Health Insurance Service of Korea, the domestic hair loss population is estimated to be approximately 10 million as of 2024. Parasites and bacteria such as Demodex folliculorum, Staphylococcus aureus, and P-acne are resident in the hair follicles and skin of animals. The proliferation of these parasites, excessive hormone secretion caused by environmental changes, and abnormal functioning of immune cells induce inflammation and itching in the scalp and hair follicles, which ultimately lead to hair loss. For hair loss patients, increased scalp exposure not only impairs the protective function against external shocks and stimuli like sunlight but also results in significant psychological problems stemming from low self-esteem and stress. Consequently, the social cost of hair loss treatment in South Korea amounts to 4 trillion won annually, while the global hair loss market is projected to reach approximately 28 trillion won. However, conventional hair loss treatment methods, such as drug therapy and laser therapy, have limitations including side effects, inconvenience, and inconsistent therapeutic effects, leading to an urgent demand for effective, non-invasive, and easy-to-use hair loss treatment solutions.

[0003] Meanwhile, recent advancements in OLEDs (Organic Light Emitting Diodes) are presenting new possibilities to address these issues. OLEDs are lightweight, flexible, and capable of adjusting the wavelength of emitted light, making them highly suitable for wearable therapeutic devices. These characteristics offer the advantage of precisely delivering light to target areas in various biomedical applications, such as wound healing, pain relief, and hair loss treatment. In particular, since OLEDs can be easily integrated into fabrics, it is possible to transform everyday clothing, such as hats, into hair loss treatment platforms, providing users with a comfortable and non-invasive treatment method. Based on these characteristics, wearable OLED hair loss patches incorporating conventional OLED technology have been attempted; however, these all utilize a bottom-emitting method where light is emitted toward the anode. Consequently, light intensity decreases depending on the substrate transmittance, resulting in insufficient delivered light energy (J / cm²) to stimulate the proliferation of dermal papilla cells. 2 There was a problem that ) was insufficient.

[0004] Accordingly, the present invention is designed to solve the above-mentioned problems and provides a top-emitting OLED hair loss care device designed on a textile-based substrate. Furthermore, the OLED hair loss care device of the present invention implements a near-infrared OLED. Near-infrared light has the characteristic of penetrating deep into biological tissues, making it effective in stimulating cellular activity within hair follicles; however, there was a concern that the performance of the substrate would deteriorate if heat generation caused by near-infrared light emission could not be controlled. However, by implementing the near-infrared OLED in a top-emitting manner in the present invention, the controllable advantage of effectively delivering optimal light energy suitable for enhancing cell activity to the cells has been obtained. Therefore, the textile-based near-infrared OLED of the present invention is expected to be widely used for hair loss treatment and, furthermore, for medical devices for various purposes.

[0005] The present invention was devised to solve the problems of the conventional technology described above.

[0006] One objective of the present invention is to provide a top-emitting organic light-emitting diode (OLED) and a method for manufacturing the same.

[0007] Another objective of the present invention is to provide a hair loss prevention or treatment device comprising the above-described top-emission organic light-emitting diode (OLED).

[0008] Another objective of the present invention is to provide a wound healing or regeneration device comprising the above-described top-emitting organic light-emitting diode (OLED).

[0009] Another objective of the present invention is to provide an anti-aging or improvement device comprising the above-described top-emission organic light-emitting diode (OLED).

[0010] Another objective of the present invention is to provide a skin care device comprising the above-described top-emission organic light-emitting diode (OLED).

[0011] However, the technical problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by those skilled in the art from the description below.

[0012] Various embodiments described herein are described with reference to the drawings. In the following description, for a complete understanding of the invention, various specific details, such as specific forms, compositions, and processes, are described. However, specific embodiments may be practiced without one or more of these specific details, or in combination with other known methods and forms. In other examples, known processes and manufacturing techniques are not described as specific details so as not to unnecessarily obscure the invention. Reference throughout this specification to "one embodiment" or "an embodiment" means that the particular features, forms, compositions, or characteristics described in association with the embodiment are included in one or more embodiments of the invention. Accordingly, the context of "in one embodiment" or "an embodiment" expressed at various places throughout this specification does not necessarily represent the same embodiment of the invention. Additionally, particular features, forms, compositions, or characteristics may be combined in any suitable way in one or more embodiments.

[0013] Unless otherwise specifically defined in the specification, all scientific and technical terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains.

[0014] Throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0015] In one embodiment of the present invention, a top-emitting organic light-emitting diode (OLED) and a method for manufacturing the same are provided.

[0016] Throughout the specification of the present invention, the term organic light-emitting diode refers to a thin-film light-emitting diode in which a light-emitting layer is made of a film of an organic compound that emits light in response to an electric current.

[0017] When voltage is applied to the cathode and anode, electrons and holes are injected from each electrode, and the injected electrons and holes pass through the respective electron transport layer and hole transport layer to combine in the emissive layer. The energy from this combination causes the light-emitting material in the emissive layer to enter an excited state, and light is generated when it returns from the excited state to the ground state. Metal thin films such as aluminum, silver, magnesium alloys, and calcium can be used for the cathode, and transparent metal thin films such as indium tin oxide (ITO) can be used for the anode. The generated light is reflected by the reflective surface and passes through the transparent electrode and the substrate.

[0018] In the present invention, the organic light-emitting diode (hereinafter, OLED) is characterized by having a multilayer thin film structure in which nine layers, including an anode, a hole injection layer (HIL), a hole transport layer (HTL), an electron block layer (EBL), an emission layer (EML), an electron transport layer (ETL), an electron injection layer (EIL), a seed layer, and a cathode, are deposited in sequence on a substrate. At this time, an anode is formed at the bottom of the device, and the anode is composed of Al (aluminum) and deposited with a thickness of 50 to 300 nm, designed to ensure sufficient continuity and conductivity as an electrode layer. A hole injection layer (HIL) is laminated on top of the anode layer to facilitate hole injection, and the hole injection layer is composed of MoO3 (molybdenum trioxide) and formed with a thickness of 5 to 30 nm. MoO3 generally serves to lower the hole injection barrier by adjusting the energy levels between the anode layer and the organic layer. A hole transport layer (HTL) is formed on top of the hole injection layer, and the hole transport layer is composed of NPB (N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine) material and deposited with a thickness of 50 to 120 nm. The hole transport layer serves to efficiently move holes injected from the anode layer toward the emissive layer. An electron blocking layer (EBL) is disposed on top of the hole transport layer, and the electron blocking layer is composed of Mcp(1,3-bis(carbazol-9-yl)benzene) and formed with a thickness of 3 to 30 nm. The electron blocking layer plays a role in suppressing leakage of electrons (or holes) and regulating charge balance to induce efficient recombination of electrons and holes in the emissive layer.An emissive layer (EML), which is the core light-emitting region of the device, is formed on top of the electron blocking layer. The emissive layer is composed of a Pt(II) (Platinum(II))-based light-emitting material and is deposited to a thickness of 5 to 50 nm. The emissive layer is a layer in which holes and electrons recombine to form excitons, and light is emitted through the radiative annihilation of excitons. Since this layer requires relatively precise film formation, it is deposited at a low rate. An electron transport layer (ETL) is formed on top of the emissive layer. The electron transport layer is composed of TPBi (2,2',2''-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)) and is deposited to a thickness of 40 to 80 nm. The electron transport layer plays a role in efficiently transporting electrons injected from the cathode layer to the emissive layer and also contributes to regulating charge balance at the interface with the emissive layer. An electron injection layer (EIL) is disposed on top of the electron transport layer, and the EIL is composed of Liq (8-hydroxyquinolinolato-lithium) and formed with a thickness of 0.5 to 5 nm. Liq serves to improve electron injection by lowering the electron injection barrier from the cathode layer, and is deposited at a slow rate because it is formed as a very thin layer. A seed layer is additionally formed on top of the EIL, and the seed layer is composed of Al (aluminum) and deposited with a thickness of 0.5 to 5 nm. This seed layer can be interpreted as a layer intended to improve the continuity, interfacial contact, or film quality of the cathode layer by controlling the initial nucleation and growth behavior of the metal thin film when a subsequent metal cathode layer is deposited. Since the seed layer is also formed as an ultrathin film, it is deposited at a slow rate. Finally, a cathode layer is formed on the top, and the cathode layer is composed of Ag (silver) and deposited with a thickness of 5 to 100 nm. The cathode layer functions as an electrode that injects electrons into the organic layer.To summarize, the OLED device has a stacked structure of Al(Anode) / MoO3(HIL) / NPB(HTL) / mCP(EBL) / Pt(II)(EML) / TPBi(ETL) / Liq(EIL) / Al(Seed layer) / Ag(Cathode), and each layer is a multilayer organic / inorganic thin film device structure designed so that charge injection-transport-blocking-recombination-luminescence occur efficiently in sequence.

[0019] In addition, in the OLED of the present invention, the anode layer may be deposited at a rate of 2 Å / s, the hole injection layer may be deposited at a rate of 0.5 Å / s, the hole transport layer may be deposited at a rate of 0.5 to 1 Å / s, the electron blocking layer may be deposited at a rate of 0.5 Å / s, the emitting layer may be deposited at a rate of 0.2 Å / s, the electron transport layer may be deposited at a rate of 0.5 to 1 Å / s, the electron injection layer may be deposited at a rate of 0.1 Å / s, and the cathode layer may be deposited at a rate of 2 Å / s. However, it is not limited thereto.

[0020] The device of the present invention functions to form a microcavity together with a lower high-reflection electrode and simultaneously emit light in an upward direction by implementing the structure as described above.

[0021] In addition, the OLED of the present invention is characterized by using a textile material as a substrate. The textile material may be a thread, fiber, film, or a mixture thereof, but is not limited thereto.

[0022] The OLED of the present invention utilizes a flexible textile material as a substrate, thereby providing a more attractive option to the user by considering comfort, functionality, and design elements when used in a wearable device. Specific advantages may be as follows.

[0023] ① Comfortable fit: The flexible textile material adheres gently to the skin, helping users to wear the device without discomfort. This allows for long-term wear, making it highly advantageous for use as an assistive device for health.

[0024] ② Elasticity: Textile materials have excellent elasticity, allowing them to adapt to various body movements. This enables the device to remain stable even during significant physical activities such as exercise.

[0025] ③ Breathability: Flexible textiles are breathable, absorb sweat well, and dry quickly. This maintains a comfortable feeling while wearing and is particularly advantageous for development in the form of a cap as a hair loss treatment device.

[0026] ④ Lightweight: Textile materials are light and flexible, providing comfort to the extent that the user barely feels the device being worn. Due to its low weight, it can be used comfortably in daily life.

[0027] ⑤ Design potential: Textile materials can be designed with various colors and patterns, allowing for the reflection of individual user tastes. This can lead to wearable devices being perceived as fashion items rather than simple technical products.

[0028] ⑥ Possibility of functional integration: Flexible textile materials open up the possibility of integrating sensors or electronic devices. For example, heart rate monitoring sensors or temperature sensors can be embedded in the fabric to enhance the functionality of the device.

[0029] Based on the characteristics of such textile-material OLEDs, there have been conventional attempts to utilize them in various biomedical applications, such as wound healing, pain relief, and hair loss treatment. In particular, wearable OLED hair loss patches have been attempted to use everyday clothing, such as hats, as platforms for hair loss treatment; however, since these all utilize a bottom-emitting method where light is emitted toward the anode, the light intensity decreases depending on the substrate transmittance, resulting in insufficient delivered light energy (J / cm²) to stimulate the proliferation of dermal papilla cells. 2 There was a problem in that ) was insufficient. Therefore, the present invention provides a top-emitting OLED designed on a textile-based substrate to solve the above problem. Here, the top-emitting method refers to a concept in which light is emitted in the direction of the cathode layer, which is the opposite of the bottom-emitting method.

[0030] Conventional OLED substrates have a bottom-emitting structure and possess a multilayer stacked structure designed to emit light in the direction of the substrate (downward direction). These OLED devices are primarily designed to use Ag (silver) as the anode layer and Al (aluminum) as the cathode layer, and do not include a nucleation layer. In such a bottom-emitting structure, since light must pass through the substrate and the bottom electrode, light loss is prone to occur due to the light transmittance characteristics of the substrate, the transparency of the electrode, and absorption and reflection in the bottom layer. In prior research by the inventors of the present invention, it was observed that when the bottom electrode was composed of Ag, as in conventional OLED structures, the performance of the OLED deteriorated within about 10 minutes. On the other hand, in the present invention, the operating life of the OLED could be secured by configuring the bottom electrode with Al. Furthermore, it was found that if the conventional OLED structure was fabricated by simply flipping it over to emit light toward the opposite side of the substrate, the electrical performance of the OLED deteriorated significantly.

[0031] In addition, when the bottom emission method is intended to be used by attaching the element to a wearable material such as a textile (e.g., a hat), there is a structural mismatch between the direction in which light is actually to be transmitted (i.e., towards the wearer's skin or scalp) and the direction of emission.

[0032] On the other hand, the OLED device of the present invention is configured in a top-emitting manner, so that light generated in the light-emitting layer is directly emitted in the upward direction of the device. Accordingly, when the OLED device of the present invention is attached to the inner side of a textile material, particularly a wearable product such as a hat, light can be directly irradiated toward the wearer's scalp without a separate optical direction conversion structure. That is, since light reaches the treatment target area (scalp) directly, the light irradiation efficiency required for phototherapy purposes, such as hair loss treatment, can be increased, and the effect of substantially increasing the amount of light delivered to the scalp even under the same electrical driving conditions is provided.

[0033] In addition, since light does not need to pass through the substrate in the top emission structure, constraints on the substrate material and light transmittance are relatively reduced. Therefore, the OLED device of the present invention can be implemented on various substrate structures applied to textiles (e.g., opaque or translucent support layers, adhesive layers, etc.), and can alleviate structural limitations that may occur during textile attachment. Furthermore, light absorption loss in the lower layer, which can be an issue in the bottom emission method, is reduced, providing a configuration that is advantageous in terms of luminous efficiency and light extraction efficiency.

[0034] Consequently, the OLED device of the present invention has significant advantages over conventional bottom-emitting OLED devices in terms of structural suitability for directly emitting light toward the wearer's scalp, substantial improvement in light irradiation efficiency, and increased design freedom when applied to textiles. In particular, the present invention provides an effect distinguished from the prior art in that it does not merely modify the OLED light-emitting structure, but optimizes the direction of light emission so that it can be attached to wearable textiles such as hats to perform phototherapy functions such as hair loss treatment.

[0035] Furthermore, the OLED of the present invention is characterized as being a near-infrared OLED that emits light in the near-infrared band. The near-infrared light may be defined as light in the wavelength band of 700 to 1400 nm, and more preferably may be defined as light in the wavelength band of 700 to 1000 nm, light in the wavelength band of 700 to 900 nm, light in the wavelength band of 700 to 800 nm, light in the wavelength band of 750 to 800 nm, or light in the wavelength band of 730 nm, but is not limited thereto.

[0036] Near-infrared radiation has the characteristic of being able to penetrate deep into biological tissues, making it effective for stimulating cellular activity within tissues; however, there was a concern that the performance of the substrate would deteriorate if heat generation caused by near-infrared emission could not be controlled. However, the OLED of the present invention achieves the advantage of controllability by implementing the near-infrared OLED in a top-emitting manner, thereby enabling the effective delivery of optimal light energy suitable for enhancing cell activity to the cells.

[0037] In another aspect of the present invention, a hair loss prevention or treatment device comprising the OLED of the present invention described above is provided.

[0038] Throughout the specification of this invention, hair loss refers to a condition in which hair is absent in areas where it should normally be present. It is a condition affecting millions of people worldwide; according to a survey by the National Health Insurance Service of Korea, the domestic hair loss population is estimated to be approximately 10 million as of 2024. Parasites and bacteria such as Demodex folliculorum, Staphylococcus aureus, and P-acne are resident in the hair follicles and skin of animals. Their proliferation, excessive hormone secretion due to environmental changes, and abnormal functioning of immune cells induce inflammation and itching in the scalp and hair follicles, which become the cause of hair loss. For hair loss patients, increased exposure of the scalp not only impairs the function of protecting the scalp and brain from external shocks or stimuli such as sunlight, but also leads to low self-esteem and significant psychological problems caused by psychological stress. Therefore, in South Korea, the annual social cost for hair loss treatment amounts to 4 trillion won, and the global hair loss market is projected to be approximately 28 trillion won. However, conventional hair loss treatment methods, such as drug therapy and laser therapy, have limitations including side effects, inconvenience, and inconsistent therapeutic effects, leading to an urgent demand for effective, non-invasive, and easy-to-use hair loss treatment solutions.

[0039] In this regard, the textile-based top-emitting near-infrared OLED provided by the present invention is suitable for development as a wearable device for the prevention or treatment of hair loss. In addition to the aforementioned comfortable fit, elasticity, breathability, lightness, design possibilities, and functional integration possibilities, the OLED of the present invention has been proven to have a significant cell proliferation effect in a cell proliferation effect test using human dermal papilla cells (hDPCs; c-12071, PromoCell).

[0040] In another aspect of the present invention, a wound healing or regeneration device comprising the OLED of the present invention described above is provided.

[0041] The skin serves as the body's primary defense mechanism, providing a barrier against microbial invasion. Therefore, the primary objective in treating skin injuries such as lacerations, burns, and abrasions is to rapidly suture the wound site to prevent infection. Wound healing is generally a complex process involving three stages: inflammation, proliferation, and remodeling. The first stage involves clotting for hemostasis, the influx of neutrophils to destroy bacteria and necrotic tissue, and the subsequent influx of macrophages. During the second stage, angiogenesis occurs, in which endothelial cells and fibroblasts expand from the surrounding area into the wound site to contribute to the production of granulation tissue. The formation of granulation tissue is an essential process for reepithelialization. During the final stage, the levels of collagen production and destruction become balanced, and the structurally re-epithelialized skin regains physical strength to restore function. Wound healing is delayed or impaired when any of these processes fail to function properly or in a timely manner. This can lead to chronic wounds, which are not only a significant personal issue but also a costly clinical problem. Therefore, ongoing efforts are being made to promote rapid wound healing to reduce the risk of secondary infection and prevent the inflammatory response from persisting. Meanwhile, it is already known that light of various wavelengths emitted from OLEDs, particularly infrared and near-infrared rays, is effective in promoting cell regeneration and healing. These lights help accelerate the wound healing process by improving blood circulation, reducing inflammation, and activating cellular metabolic processes.

[0042] In this regard, the textile-based top-emitting near-infrared OLED provided in the present invention is suitable for development as a wearable device for the treatment or regeneration of wounds. In addition to the aforementioned comfortable fit, elasticity, breathability, lightness, design possibilities, and functional integration possibilities, the OLED of the present invention has been proven to have the effect of promoting cell migration from the area surrounding the scratch to the scratch area in a scratch test using cells.

[0043] In another aspect of the present invention, an aging prevention or improvement device comprising the OLED of the present invention described above is provided.

[0044] Aging is a complex process occurring in the cells and tissues of living organisms, leading to various physiological changes. At the cellular level, aging primarily involves the degeneration of cell structure and function. Cells grow and regenerate through repeated division, but their ability to divide decreases over time. This is the result of the combined influence of factors such as oxidative stress and genetic damage, including the shortening of telomere length with repeated division. Cells can be damaged by environmental factors or reactive oxygen species generated during metabolic processes, and this damage affects various cellular components such as DNA, proteins, and cell membranes. As this damage accumulates over time, cellular function deteriorates, eventually leading to apoptosis or loss of function. This is referred to as cellular aging, and a population of aged cells leads to tissue aging. Meanwhile, it is already known that light of various wavelengths emitted from OLEDs, particularly infrared and near-infrared light, can have a positive effect on gene expression and metabolism in cells and tissues. Such light helps improve cellular physiological function, reduce oxidative stress, and promote cell regeneration.

[0045] In this regard, the textile-based top-emitting near-infrared OLED provided in the present invention is suitable for development as a wearable device for preventing or improving aging. In addition to the aforementioned comfortable fit, elasticity, breathability, lightness, design possibilities, and functional integration possibilities, the OLED of the present invention has been proven to have the effect of reducing SA-β-gal, known as a biomarker of aging cells, when irradiated onto cells.

[0046] In another aspect of the present invention, a skin beauty device comprising the OLED of the present invention described above is provided.

[0047] Skin beauty effects can be clearly derived from the wound healing or regenerative effects and anti-aging or improvement effects of the OLED of the present invention described above. Here, skin beauty is a concept that encompasses skin antioxidant, anti-inflammatory, and wrinkle inhibition. Specifically, the skin antioxidant refers to inhibiting skin oxidation, which is a concept that inhibits cellular aging. Oxygen entering the body through respiration creates energy necessary for the human body while simultaneously generating free radicals, which are harmful excess oxygen. Since free radicals attack normal cells in the body and act as a cause of aging or various diseases, removing free radicals is a method to prevent cellular oxidation (aging), and inhibiting such cellular oxidation is what constitutes antioxidant activity. The anti-inflammatory refers to the efficacy of soothing and resisting inflammation. In terms of skin beauty, the anti-inflammatory function can be viewed as protecting and stabilizing the skin, as well as performing disinfection and sterilization actions. The wrinkles mentioned above are a phenomenon in which the skin folds due to degeneration of collagen fibers, elastic fibers, etc., within the dermis caused by various factors including sunlight, and a decrease in skin moisture leading to reduced skin elasticity. The absorption of subcutaneous fat also further exacerbates wrinkles. In aging skin, wrinkles form due to the deterioration of collagen fibers, which constitute the majority of the Extracellular Matrix, and changes in skin components such as hyaluronic acid and ceramide. Furthermore, reduced skin hydration leads to dryness and a loss of elasticity. In aging skin, the number of dermal and epidermal cells decreases, and impaired cellular function results in wrinkle formation, pigmentation, dryness, thickened skin, and reduced elasticity. Exposure to ultraviolet rays induces the production of Matrix Metalloproteinases (MMPs) in the skin, which cause the degradation of Extracellular Matrix ECM proteins such as collagen, elastin, and proteoglycans. Among these, MMP-1 is a collagen-degrading enzyme that breaks down Type 1 collagen (COL1A1) and Type 3 collagen (COL3A1), which are the main forms of the skin.It has been reported that collagen synthesis decreases in naturally aged and photoaged skin. Therefore, anti-wrinkle or wrinkle inhibition refers to delaying, inhibiting, or improving the formation of wrinkles.

[0048] In this regard, the textile-based top-emitting near-infrared OLED provided in the present invention is suitable for development as a wearable device for skin care. In addition to the aforementioned comfortable fit, elasticity, breathability, lightness, design possibilities, and functional integration possibilities, the OLED of the present invention can be expected to have the effect of maintaining healthy skin, such as repairing damage to skin tissue and inhibiting aging, through the effect of promoting cell regeneration and increasing anti-aging activity when irradiated onto cells.

[0049] The present invention has a top-emitting near-infrared OLED hair loss care device designed on a textile-based substrate that controls heat generation caused by near-infrared light emission, thereby enabling controllable effects to effectively deliver optimal light energy suitable for enhancing cell activity to the cells.

[0050] However, the effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description of the invention or the claims.

[0051] Figure 1 shows the deposition sequence of a wavelength-tunable top-emitting near-infrared OLED (Top-emitting NIR OLED) according to one embodiment of the present invention.

[0052] FIG. 2 shows the transmittance characteristics of a textile (180 μm) in the UV~NIR band (3~800 nm) according to an embodiment of the present invention.

[0053] FIG. 3 shows the transmittance characteristics of a textile (180 μm) in the NIR band (7 to 800 nm) according to an embodiment of the present invention.

[0054] FIG. 4 shows a driving image of a textile-based top-emitting NIR OLED according to an embodiment of the present invention.

[0055] Figure 5 shows the results of confirming the heat generation stability of a textile-based Top-emitting NIR OLED according to an embodiment of the present invention.

[0056] Figure 6 shows the results of verifying the wavelength-tunable characteristics of a textile-based top-emitting NIR OLED according to one embodiment of the present invention, including current density-voltage-radiant luminance (left) and electroluminescence according to wavelength (right).

[0057] Figure 7 shows the results of verifying the water resistance (left) and flexibility (right) of a textile-based Top-emitting NIR OLED according to one embodiment of the present invention.

[0058] Figure 8 shows the results of verifying the flexibility of a textile-based top-emitting NIR OLED according to one embodiment of the present invention, by confirming the current density-voltage-radiant luminance (left) and electroluminescence (right) as changes in the characteristics of the device when bent up to 10,000 times under a stress of 2.1%.

[0059] Figure 9 shows the results of verifying the difference in current density (J)-voltage (V) and driving lifespan according to the electrode structure change of a textile-based Top-emitting NIR OLED (Table 1) and a conventionally developed Bottom-emitting NIR OLED (Table 2) according to one embodiment of the present invention.

[0060] Figure 10 shows the results of confirming the difference in OLED driving images between a textile-based Top-emitting NIR OLED (Table 1) and a conventionally developed Bottom-emitting NIR OLED (Table 2) according to one embodiment of the present invention.

[0061] FIG. 11 shows the results of confirming that the light-emitting area of ​​a textile-based Top-emitting NIR OLED according to one embodiment of the present invention can be stably expanded.

[0062] Figure 12 shows the results of confirming the performance difference according to the top electrode structure of the Top-emitting NIR OLED proposed in the present invention, according to one embodiment of the present invention.

[0063] Figure 13 shows the results of confirming the effect of textile-based top-emitting NIR OLED on dermal papilla cell proliferation according to one embodiment of the present invention, and shows the cell proliferation results when irradiated with visible light (a) in the 470-700 nm band and near-infrared light (b) in the 700-800 nm band.

[0064] Figure 14 is a result confirming the cell migration promoting effect of a textile-based Top-emitting NIR OLED according to one embodiment of the present invention.

[0065] FIG. 15 is a result confirming the anti-aging activity promoting effect of a textile-based top-emitting NIR OLED according to one embodiment of the present invention.

[0066] In this invention, a wavelength-tunable top-emitting near-infrared OLED was developed by controlling the cavity length using the micro-cavity effect. This allows for free wavelength adjustment in the near-infrared band of 700–800 nm, making it possible to produce customized OLEDs corresponding to wavelengths that induce optimal hair growth. The layers were deposited on a textile substrate in the order of Anode / HIL / HTL / EBL / EML / ETL / EIL / Seed layer / Cathode, and it is a top-emitting method in which light is emitted toward the cathode layer.

[0067] The present invention will be described in more detail below through examples. These examples are intended solely to explain the present invention more specifically, and it will be obvious to those skilled in the art that the scope of the present invention is not limited by these examples according to the gist of the invention.

[0068] Throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0069] Example.

[0070] 1. Textile-based near-infrared OLED manufacturing

[0071] In this invention, a wavelength-tunable top-emitting near-infrared OLED was developed by controlling the cavity length using the micro-cavity effect (hereinafter referred to as Top-emitting NIR OLED). This enables free wavelength tuning in the near-infrared band of 700–800 nm, making it possible to fabricate customized OLEDs corresponding to wavelengths that induce optimal hair growth. The NIR OLED was fabricated using a thermal evaporator, and the deposition of organic materials and electrodes was 2 × 10 -6 The process was performed under vacuum pressure conditions of Torr. Deposition was carried out on a textile substrate in the order of Anode / HIL / HTL / EBL / EML / ETL / EIL / Seed layer / Cathode (Fig. 1), using a top-emitting method where light is emitted toward the cathode layer. The specific electrode and organic material deposition processes are shown in Table 1 below.

[0072] Deposition Sequence | Role | Material Type | Thickness 1 Anode | Al 100 nm 2 HIL Mo O 3 10 nm 3 HTL NPC | B 87 nm 4 EB L M P P 15 nm 5 E M P T (II) 20 nm 6 E L T P Bi 60 nm 7 E IL I Q 2 nm 8 Seed layer | Al 2 nm 9 Cathode | Ag 30 nm

[0073] In the above OLED, the anode layer is deposited at a rate of 2 Å / s, the hole injection layer is deposited at a rate of 0.5 Å / s, the hole transport layer is deposited at a rate of 0.5 to 1 Å / s, the electron blocking layer is deposited at a rate of 0.5 Å / s, the emitting layer is deposited at a rate of 0.2 Å / s, the electron transport layer is deposited at a rate of 0.5 to 1 Å / s, the electron injection layer is deposited at a rate of 0.1 Å / s, and the cathode layer is deposited at a rate of 2 Å / s. 2. Confirmation of the superiority of the top-emitting method. The top-emitting NIR OLED of the present invention is not affected by the physical and optical properties of the substrate, so it can effectively transmit light energy to cells, and has superior characteristics compared to bottom-emitting NIR OLEDs in terms of mitigating heat generation problems and the stability of light output. This is proven by the transmittance characteristics using a polyester-based textile (180 μm). Since light is emitted through a substrate in bottom-emitting OLEDs, the transmittance characteristics of the substrate directly affect the light output efficiency. For example, when a bottom-emitting NIR OLED is applied to a polyester substrate with a transmittance of 17–19% in the NIR (7–800 nm) band, only 17–19% of the OLED light energy is transmitted (Figs. 2 and 3) (transmittance calculation: see Equation 1).

[0074] [Mathematical Formula 1]

[0075]

[0076] (In Equation 1, T: transmittance, I0: intensity of light before transmission, It: intensity of light after transmission)

[0077] On the other hand, Top-emitting OLEDs have a structure in which light is emitted to the opposite side of the substrate, so the OLED optical properties are maintained regardless of the transmittance of the substrate (Fig. 4). This enables high-efficiency emission without loss of OLED light energy even when the OLED is applied to a polyester substrate.

[0078] This serves as the foundation for mitigating the heat generation problem of OLEDs and stabilizing their optical characteristics. Bottom-emitting OLEDs require an increased driving voltage to maintain the same light output performance when the substrate transmittance is low, which causes an increase in driving temperature and potentially poses a risk of burns from human contact. Additionally, optical characteristics (e.g., wavelength, light intensity) may vary depending on the type or characteristics of the substrate used. However, Top-emitting OLEDs maintain OLED optical characteristics regardless of the substrate type and, because there is no loss of light energy, heat generation problems can be minimized and human safety can be ensured. As a result of verifying the thermal stability of the Top-emitting NIR OLED manufactured in this invention, it was found to have an operating temperature of 34°C, which is approximately 8°C lower than 42°C—the temperature that causes low-temperature burns—unlike conventional treatment methods where localized heat generation problems existed. Furthermore, the operating temperature could be lowered to approximately 27°C by attaching thermal tape (Fig. 5). This demonstrates safety from burns. In other words, Top-emitting OLEDs operate independently of the substrate, allowing them to maintain consistent optical characteristics even in various substrate environments and ensuring safety from burns.

[0079] 3. Verification of Wavelength Tunable Characteristics of Top-emitting NIR OLED

[0080] The Top-emitting NIR OLED of the present invention is an OLED capable of wavelength tuning by adjusting the cavity length using the micro-cavity effect. Therefore, the Top-emitting NIR OLED of the present invention enables free wavelength adjustment in the near-infrared band of 700 to 800 nm, and based on this, it was confirmed that it is possible to fabricate a customized OLED corresponding to the wavelength that induces optimal hair growth (Fig. 6). This wavelength-tunable characteristic is 10 W m⁻¹, which is the minimum intensity required for light therapy. -2 sr -1Based on light intensity characteristics exceeding [the value], it suggests the possibility of application for hair loss treatment.

[0081] 4. Verification of the operational stability of textile-based top-emitting NIR OLEDs in everyday life

[0082] The textile-based top-emitting NIR OLED of the present invention ensures water resistance by depositing Parylene-C or PET, which are biocompatible materials, on the outermost layer. This coating protects the NIR OLED from sweat and moisture from the external environment (Fig. 7). In addition, it was confirmed that electrical and optical properties are maintained even after bending up to 10,000 times under a stress condition of 2.1% (Fig. 8). The water resistance and flexibility of these textile-based NIR OLEDs suggest the possibility of stable operation in everyday life.

[0083] 5. Verification of electrical performance differences compared to conventional bottom-emitting NIR OLEDs

[0084] Conventional OLED substrates have a bottom-emitting structure and a multilayer stacked structure designed to emit light in the direction of the substrate (downward direction). These OLED devices are primarily designed to use Ag (silver) as the anode layer and Al (aluminum) as the cathode layer, and do not include a nucleation layer. In such a bottom-emitting structure, since light must pass through the substrate and the bottom electrode, there was a problem in that light loss was likely to occur due to the light transmittance characteristics of the substrate, the transparency of the electrode, and absorption and reflection in the bottom layer.

[0085] To clearly confirm these differences, an OLED was fabricated as a conventional Bottom-emitting NIR OLED (ACS Appl. Mater. Interfaces 2023, 15, 57415-57426) having the electrodes and organic material deposition process of Table 2 below.

[0086] Deposition Sequence Role Material Type Thickness 1 Anode Ag 3 5 nm 2 HIL Mo O 3 10 nm 3 HTL NBP- 4 EB L M CP 15 nm 5 EML T(II) 20 nm 6 ETL TBP Bi 60 nm 7 EILL IQ 2 nm 8 Cathode Al 100 nm

[0087] As a result of verifying the difference in electrical performance between the Top-emitting NIR OLED of the present invention (Table 1) and the conventional Bottom-emitting NIR OLED (Table 2), it was observed that when the bottom electrode was composed of Ag, as in the conventional Bottom-emitting NIR OLED, the OLED performance deteriorated in about 10 minutes. On the other hand, the Top-emitting NIR OLED was able to secure the operating life of the OLED by configuring the bottom electrode with Al (Fig. 9). In a structure where the Top-emitting NIR OLED of the present invention (Table 1) and the conventional Bottom-emitting NIR OLED (Table 2) were bonded to a textile, the difference in light emission between the two devices was even more evident. In the case of the conventional Bottom-emitting NIR OLED, due to its structural characteristics, the NIR OLED light passed through the opaque textile, resulting in a significant reduction in light. However, since the Top-emitting NIR OLED proposed in the present invention emits light in the opposite direction of the substrate, it is not affected by the transmittance characteristics of the textile, and it was confirmed that no reduction in light was observed (Fig. 10). This also implies that the OLED of the present invention, as a textile-based NIR OLED, can have its light-emitting area expanded to cover a wide irradiation area. In the present invention, the light-emitting area of ​​the textile-based top-emitting NIR OLED is 9 mm 2 69 mm from 2 , furthermore 1,024 mm 2It was experimentally proven that it can be expanded stepwise up to (Fig. 11). In addition, an OLED was fabricated by simply flipping the structure of Table 2 to emit light to the opposite side of the substrate (Inverted OLED). When the difference in electrical performance was checked, it was confirmed that the electrical performance of the OLED was significantly degraded (Fig. 12). Therefore, it was found that structural development of the OLED is essential for fabricating Top-emitting OLEDs, and the Top-emitting NIR OLED of the present invention was developed through OLED performance optimization based on modification of the electrode structure.

[0088] 6. Confirmation of the dermal papilla cell proliferation effect of textile-based top-emitting NIR OLED

[0089] To confirm the usefulness of near-infrared OLEDs (NIR OLEDs) as hair loss care devices, the proliferative effect of light irradiation on dermal papilla cells was examined (Fig. 13). For this purpose, human dermal papilla cells (hDPCs; c-12071, PromoCell) subcultured 5 to 13 times were prepared and cultured in Follicle DPC Growth Medium (c-26501, PromoCell) containing 0.1% Gibco™ antibiotic-antifungal agent (Thermo Fisher Scientific, Waltham, MA, USA) under conditions of 37°C, 5% CO₂, and humidification. The cells were irradiated with visible light in the 470–660 nm wavelength range or near-infrared light in the 700–800 nm wavelength range for 10, 20, or 30 minutes, and changes in the cell proliferation rate were tracked after 6 hours. As a result of the test, light irradiation in the Blue–Green (470–530 nm) band did not affect the proliferation of dermal papilla cells (Fig. 13a). On the other hand, Red and NIR light irradiation significantly proliferated cells, with Red Light (630–660 nm) showing a maximum cell proliferation effect of 20% and NIR Light (700–800 nm) showing a maximum cell proliferation effect of 55% (Fig. 13b). In addition, by establishing optimal light therapy conditions according to wavelength and irradiation time, cell proliferation was further enhanced by 55% when 730 nm light was irradiated for 20 minutes. These results demonstrate that NIR light has deeper tissue penetration than Red Light and acts more effectively on dermal papilla cells. The device of the present invention can provide high efficiency in hair loss treatment by utilizing these characteristics of NIR OLED.

[0090] 7. Confirmation of Cell Migration-Promoting Effect of Textile-Based Top-emitting NIR OLED

[0091] Cell migration plays a crucial role in tissue regeneration within damaged tissues. Cell migration refers to the function of cells moving to the site of tissue damage to facilitate the regeneration process. Cells with excellent migration capabilities rapidly reach the damaged tissue, secrete necessary growth factors, and contribute to the formation of new cells. This is essential for accelerating the speed of tissue recovery and quickly restoring function.

[0092] To confirm whether the Top-emitting NIR OLED of the present invention can function as a care device for hair loss as well as various damaged tissues, its cell migration-promoting effect was verified. For this purpose, hDPCs (passed three times) were inoculated into a 6-well plate at a concentration of 2.5 × 10⁵ cells / well and cultured until the cells reached an 80% fusion state. After removing the culture medium, a horizontal scratch was created on the surface of the cell culture using a 1000 μL sterile pipette tip. The detached cells were washed away with PBS (21-030-CVR, Corning), 2 mL of DPC culture medium was added, and a horizontal reference line was marked on the bottom of the plate to secure the same analysis area. Subsequently, the plate was placed on a lighting device and irradiated with OLED light under controlled conditions. The region of interest was then photographed using a microscope (Nikon, ECLIPS Ts2) at 2-hour intervals for 16 to 24 hours, based on the reference mark. The degree of cell migration within the scratch area was analyzed using the ImageJ Wound Healing Size Tool plugin, which measured the scratch area, wound healing rate, and average values.

[0093] In addition to the Top-emitting NIR OLED of the present invention (indicated as TOP-NIR), a light irradiation treatment (indicated as Cont) was used as a control group, and an OLED in the Red Light (630~660 nm) band (indicated as Red OLED) and a conventional Bottom-emitting NIR OLED (indicated as ITO-NIR in Table 2) were used as comparison groups.

[0094] As a result of the test, all light-irradiated test groups showed superior cell migration promotion effects compared to the light-irradiated non-treatment (Cont) (Fig. 14). This demonstrates the wound healing promotion function of the Top-emitting NIR OLED of the present invention and suggests the possibility of application as a wound healing promotion device in various tissues.

[0095] 8. Confirmation of the anti-aging activity-promoting effect of textile-based top-emitting NIR OLEDs

[0096] Cellular anti-aging activity helps cells reduce oxidative stress and maintain their survival and function. While the regeneration process in aging cells does not proceed smoothly due to various functional declines, anti-aging activity keeps cells healthy, thereby increasing efficiency in the regeneration process.

[0097] To confirm whether the Top-emitting NIR OLED of the present invention can function as an anti-aging device in various tissues, its anti-aging activity-promoting effect was verified. For this purpose, hDPCs (passed 13 times) were inoculated into a 6-well plate at a concentration of 1 × 10⁵ cells / well and cultured for 24 hours. They were then placed in a lighting device, irradiated with OLED light under controlled conditions, and cultured for an additional 2 days. After subculturing the cells at half density in a 6-well plate for an additional 4 days, SA-β-gal activity was analyzed using a tissue staining kit (#9860S, Cell Signaling) according to the manufacturer's instructions. SA-β-gal is known as a biomarker for senescent cells, and SA-β-gal activity increases in aging cells (Fig. 15).

[0098] In addition to the Top-emitting NIR OLED of the present invention (indicated as TOP-NIR), light-irradiated Young-DPCs (passage 3) or Old-DPCs (passage 13) were used as control groups, and an OLED in the Red Light (630~660 nm) band (indicated as Red OLED) and a conventional Bottom-emitting NIR OLED (indicated as ITO-NIR in Table 2) were used as comparison groups.

[0099] As a result of the test, the Top-emitting NIR OLED (TOP-NIR) of the present invention was found to have a significantly more pronounced anti-aging activity-promoting effect compared to Bottom-emitting NIR OLED (ITO-NIR) or Red Light band OLED (Red OLED), and was similar to the effect of reversing time by nearly 10 passages. This demonstrates the excellent anti-aging function of the Top-emitting NIR OLED of the present invention and suggests the possibility of its application as an anti-aging device in various tissues.

[0100] Foregoing, specific parts of the present invention have been described in detail. It is evident to those skilled in the art that such specific descriptions are merely preferred embodiments and do not limit the scope of the invention. Accordingly, the actual scope of the invention is defined by the appended claims and their equivalents.

[0101] In the present invention, by implementing a near-infrared OLED using a top-emitting method, the controllable advantage of effectively delivering optimal light energy suitable for enhancing cell activity to cells has been obtained. Therefore, the textile-based near-infrared OLED of the present invention is expected to be widely used in hair loss treatment and, furthermore, in medical devices for various purposes.

Claims

1. A top-emitting organic light-emitting diode having an anode layer, a hole injection layer, a hole transport layer, an electron block layer, an emission layer, an electron transport layer, an electron injection layer, a seed layer, and a cathode layer deposited in sequence on a substrate.

2. In Paragraph 1, An organic light-emitting diode, wherein the substrate is a textile material substrate.

3. In Paragraph 2, An organic light-emitting diode, wherein the textile material is a thread, fiber, film, or a mixture thereof.

4. In Paragraph 1, The above-described top emission method is an organic light-emitting diode in which light is emitted in the direction of the cathode layer.

5. In Paragraph 1, The above anode layer and nucleation layer are composed of Al (aluminum), and An organic light-emitting diode in which the above-mentioned cathode layer is composed of Ag (silver).

6. In Paragraph 1, The above organic light-emitting diode is an organic light-emitting diode that emits light in the near-infrared band.

7. In Paragraph 6, An organic light-emitting diode in which the above near-infrared band light has a wavelength of 700 to 1400 nm.

8. A step of sequentially depositing an anode layer, a hole injection layer, a hole transport layer, an electron block layer, an emission layer, an electron transport layer, an electron injection layer, a seed layer, and a cathode layer on a substrate; comprising a method for manufacturing a top-emitting organic light-emitting diode.

9. A hair loss prevention or treatment device comprising an organic light-emitting diode according to any one of claims 1 to 7.

10. A wound healing or regeneration device comprising an organic light-emitting diode according to any one of claims 1 to 7.

11. An aging prevention or improvement device comprising an organic light-emitting diode according to any one of claims 1 to 7.

12. A skin beauty device comprising an organic light-emitting diode according to any one of claims 1 to 7.

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