Light-emitting diode film

Abstract

To provide a light-emitting diode film that protects an LED and an electrode, and is excellent in adhesion reliability, and in re-workability after adhesion.SOLUTION: A light-emitting diode film includes: a substrate; an electrode layer formed on at least a portion of the substrate; solder formed on at least a portion of the electrode layer; a light-emitting diode positioned on the solder and connected to the electrode layer; a molding layer applied to the entire surface of the substrate, the electrode layer, and the light-emitting diode; and a variable adhesive film positioned on the molding layer. The light-emitting diode film satisfies the following Equation 1. The light-emitting diode film protects an LED and the electrode, has excellent adhesion reliability, and excellent re-workability after adhesion.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a light-emitting diode film. [Background technology]

[0002] With the development of the information society, the demand for display devices has increased in various forms, and in response, various display devices such as LCD (Liquid Crystal Display), PDP (Plasma Display Panel), ELD (Electro Luminescent Display), VFD (Vacuum Fluorescent Display), OLED (Organic Light Emitting Diode), and LED (Light Emitting Diode) have been researched and used recently. Recently, display devices have been installed indoors and outdoors and used for purposes such as advertising. In particular, transparent LED displays clearly show objects behind the product when the power is off, and can display various content like digital signage when the LED is turned on.

[0003] Among transparent LED displays, a transparent LED film is a display device in which light-emitting diodes (hereinafter referred to as "LEDs") are provided as light sources on a thin film. A transparent LED display film may include multiple LEDs, and can display intended images by operating the LEDs in response to a driving signal transmitted from the outside. Since such a transparent LED display film is entirely made of film, it can have a thin, lightweight, and flexible structure.

[0004] Transparent LED display films can be attached to various surfaces, such as curved or flat surfaces, for various purposes, and must have excellent adhesive reliability in order to adhere to such surfaces. Furthermore, they must be removably removable so that they can be easily removed from the installation target if the transparent LED display film is misaligned or if foreign matter gets mixed in during the attachment process.

[0005] In order to form an adhesive layer to attach the transparent LED display film to the surface, conventional transparent LED display films require a method of punching out the LED position from a sheet made of a laminated structure of pressure-sensitive adhesive (PSA) and polyester for molding, and then attaching it after aligning the position, which has the disadvantage of being a complicated manufacturing process and taking a long time to manufacture.In addition, since the light source is located in a hole, it is vulnerable to impacts and there is a problem that defects occur when contaminants in the hole are absorbed by the metal pad or light source.

[0006] Patent Document 1 relates to a transparent light-emitting diode film, which includes a base, an electrode layer located on the base and having at least one pattern formed thereon, a pad formed on at least a portion of the electrode layer, a light-emitting diode located on the pad, and an adhesive layer formed on at least another portion of the electrode layer, the adhesive layer having an opening formed in a portion corresponding to the light-emitting diode (see FIG. 1). Patent Document 1 describes a transparent light-emitting diode film in which the base includes a highly heat-resistant material, preventing changes in state due to temperature when the film is formed.

[0007] However, in Patent Document 1 (Korean Patent Publication No. 2017-0139924 (published December 20, 2017)), the optical adhesive layer serving as the adhesive layer in the transparent light-emitting diode film is located in an area other than the light-emitting diode, as shown in FIG. 1. Therefore, after laminating the adhesive layer, an opening is formed in the area corresponding to the light-emitting diode in order to mount the light-emitting diode. The manufacturing process of mounting the light-emitting diode after forming the opening has drawbacks, such as high costs for the transparent light-emitting diode film due to the complexity of the process steps and the light-emitting diode film. In addition, impurities are likely to enter the opening where the light-emitting diode is mounted during the process of attaching the transparent light-emitting diode film to the surface after removing the protective layer. In this case, the impurities may be adsorbed to the metal pad or light source, which can lead to product damage and defects due to heating.

[0008] Furthermore, since there is no adhesive layer at the position of the opening where the light-emitting diode such as the LED chip is mounted, there is a limitation in that the adhesive reliability with the surface to which the device is to be attached is low.

[0009] As shown in Figure 2, the adhesive layer formed around the opening of conventional transparent LED display film is a laminated structure of PSA and PET. After removing the release film, impurities are likely to enter the opening during the process of attaching the adhesive layer to the surface to be attached, and there is a problem that there is little adhesive surface where the adhesive layer is present at the opening.

[0010] As part of efforts to improve the above-mentioned problems, Patent Document 2 (Korean Patent Publication No. 10-2425807 (registered on July 22, 2022) attempts to solve the problem of contaminant inflow by covering a light source located in a through-hole with a thermosetting liquid resin. Patent Document 2 includes a substrate having a front surface and a rear surface facing the front surface, an electrode layer formed on the front surface, a light source provided on the front surface and connected to the electrode layer, a first resin layer attached to the front surface of the substrate and having a through-hole that exposes at least a portion of the electrode layer and the light source to the outside, and a second resin located in the through-hole and covering the portion of the electrode layer exposed to the outside. The resin layer is a base However, because most of the liquid resin is thermosetting, shrinking during the heat curing process can cause the surface to become uneven and curved. These curves create gaps, reducing the adhesion area between the resin layer and the surface being cured, lowering the bonding and adhesion strength. To prevent this, a uniform pressure must be applied to the entire surface in the presence of a heat source to achieve flatness, which is both cumbersome and disadvantageous. For example, applying several hundred kgf of pressure to an area of ​​1 m2 requires large equipment and weight, and there is also the risk of the film becoming distorted in depth during the curing process. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Korean Patent Publication No. 2017-0139924 (Published on December 20, 2017) [Patent Document 2] Korean Patent Publication No. 10-2425807 (registered on July 22, 2022) Summary of the Invention [Problem to be solved by the invention]

[0012] Therefore, in order to solve the above-mentioned problems of the conventional technology, the present invention provides a light-emitting diode film that protects the LED and electrodes by applying a molding layer to the entire upper surface of the electrode layer, solder, and light-emitting diode, and laminating a variable adhesive film on top of the molding layer, and that has excellent adhesion reliability and reworkability after adhesion.

[0013] Also, the structure and manufacturing process of the excellent light emitting diode film are simplified to reduce manufacturing costs. [Means for solving the problem]

[0014] The present invention provides a light emitting diode film comprising: a substrate; an electrode layer formed on at least a portion of the substrate; a solder formed on at least a portion of the electrode layer; a light emitting diode located on the solder and connected to the electrode layer; a molding layer applied to the entire surface of the substrate, the electrode layer, and the light emitting diode; and a variable adhesive film located on the molding layer, wherein the light emitting diode film satisfies the following formula 1:

number

[0015] In one embodiment of the present invention, the molding layer may have an adhesive strength of 100 gf / cm or more to each of the substrate and the variable adhesive film.

[0016] In one embodiment of the present invention, the molding layer may have a Young's modulus of 0.05 to 50 MPa.

[0017] In an embodiment of the present invention, the molding layer may be formed by UV curing a molding liquid.

[0018] In one embodiment of the present invention, the molding liquid may have a cure shrinkage rate of 13% or less.

[0019] In one embodiment of the present invention, the viscosity of the molding liquid may be in the range of 100 cps to 2,000 cps.

[0020] In one embodiment of the present invention, the molding liquid may include an oligomer or polymer selected from one or more oligomers, polymers, and / or derivatives thereof selected from silicone acrylates, acrylates, urethane acrylates, urethanes, butylenes, isobutylenes, and rubbers, a UV initiator, and an additive.

[0021] In one embodiment of the present invention, the molding liquid may additionally include inorganic scattering particles, organic scattering particles, light absorbing particles, or a combination thereof.

[0022] In one embodiment of the present invention, the molding liquid may be solvent-free.

[0023] In one embodiment of the present invention, the variable adhesive film includes a base film and a variable adhesive layer on the base film, and the base film may be located directly on the molding layer.

[0024] In one embodiment of the present invention, the variable adhesive layer can be attached to the surface of the target object.

[0025] In one embodiment of the present invention, the variable adhesive layer may have an A value of 1 or more as adhesive strength to the surface to be adhered.

number

[0026] In one embodiment of the present invention, the adhesive strength (A1) of the variable adhesive layer to the adherend surface may be 50 gf / in or less.

[0027] In one embodiment of the present invention, the adhesive strength (A2) of the variable adhesive layer to the surface to be adhered may be greater than 50 gf / in.

[0028] In one embodiment of the present invention, the surface to be adhered may be made of glass or plastic.

[0029] In one embodiment of the invention, the variable adhesive layer may be a pressure sensitive adhesive.

[0030] In one embodiment of the present invention, a release film may be included on the variable adhesive layer.

[0031] In one embodiment of the present invention, the variable adhesive layer may have a thickness of 50 to 150 μm.

[0032] In one embodiment of the present invention, the substrate may have a light absorbing, light blocking or light scattering function.

[0033] In one embodiment of the present invention, one or more layers of the base film and the variable adhesive layer in the variable adhesive film may have a light absorbing, light blocking or light scattering function.

[0034] In one embodiment of the present invention, the variable adhesive film may have a transmittance of 30 to 80%.

[0035] In an embodiment of the present invention, a protective film or protective coating layer may be additionally included under the other surface of the substrate having the electrode layer formed on one surface thereof.

[0036] In an embodiment of the present invention, the protective film includes an adhesive layer, a base layer, and a protective coating layer, and the adhesive layer may be disposed facing the substrate.

[0037] In one embodiment of the present invention, the protective coating layer may have a light absorbing, light blocking or light scattering function. In one embodiment of the present invention, one or more of the adhesive layer, the substrate layer, and the protective coating layer may have a light absorbing, light blocking, or light scattering function.

[0038] An embodiment of the present invention provides a light emitting diode film including a contrast improvement layer directly formed under the other surface of the substrate on which the electrode layer is formed.

[0039] In an embodiment of the present invention, the light emitting diode film may include a protective film for installation at the bottom of the substrate.

[0040] In one embodiment of the present invention, the light emitting diode film may have a yellowness index (b*) of Δ5 or less after a light resistance test. [Effects of the Invention]

[0041] The present invention can provide a light emitting diode film that can protect LEDs and electrodes from external forces, has excellent adhesion reliability, and is excellent in reworkability after adhesion, thereby improving adhesion workability. Furthermore, the present invention can provide a light emitting diode film that can reduce manufacturing costs by simplifying the manufacturing process of the light emitting diode film. [Brief explanation of the drawings]

[0042] [Figure 1] 1 shows a cross-sectional view of a film as an example of a conventionally known light-emitting diode film. [Figure 2] 1 shows a cross-sectional view of a film as an example of a conventionally known light-emitting diode film. [Figure 3] 1 is a cross-sectional view of a light emitting diode film according to an embodiment of the present invention. [Figure 4] 1 is a cross-sectional view of a light emitting diode film according to an embodiment of the present invention. [Figure 5] 1 shows an embodiment in which the light-emitting diode film of the present invention is attached to the surface of an intended installation target. DETAILED DESCRIPTION OF THE INVENTION

[0043] Hereinafter, with reference to the accompanying drawings, embodiments of the present application will be described in detail so that those skilled in the art can easily understand the present application. However, the present application may be realized in various different forms and is not limited to the embodiments described herein. In order to clearly explain the present application in the drawings, parts that are not relevant to the description are omitted, and similar parts are designated by similar reference numerals throughout the specification.

[0044] Throughout this specification, when a part is said to be "connected," "attached," or "adhered" to another part, this includes not only when they are "directly connected," but also when they are "electrically connected" via another element in between.

[0045] Throughout this specification, when an element is said to be located "on," "upper," "lower," or "underlying" another element, this includes not only when the element is in contact with the other element, but also when there is another element between the two elements.

[0046] Throughout this specification, when an element is said to be "directly on," "directly on top of," "directly at the top end," "directly below," "directly below," or "directly at the bottom end" of another element, it means that the element is in contact with the other element and that there are no other elements between the two elements.

[0047] Throughout this specification, spatially relative terms such as "below," "beneath," "lower," "above," "upper," etc. may be used to easily describe the relationship of elements to one another as shown in the drawings.

[0048] Throughout this specification, the term "light emitting diode" is used to refer to a basic semiconductor diode structure (i.e., LED, etc.). In general, the terms "light emitting diode" or "LED" can refer to an organic, inorganic, or quantum dot LED chip or apparatus / device. The terms "light emitting diode," "LED," "LED chip," etc. are used interchangeably herein.

[0049] Throughout this specification, the term "intended installation object" refers to an object or article to which the "light-emitting diode film" of the present invention is ultimately attached, and is understood to include, but is not limited to, an outdoor wall surface, an indoor ceiling, an indoor wall surface, the side or window of a vehicle, a banner, a poster, a flyer, etc. In the present invention, the term "intended installation object" should be interpreted broadly in consideration of the object, installation location, purpose of use, application, etc. to which the "light-emitting diode film" is used / attached or can be used / attached.

[0050] The light-emitting diode film according to the present invention is attached to a "receiving surface" or "adhered surface," which is one side of the intended installation target. Throughout this specification, the terms "receiving surface," "receiving surface," "adhered surface," and "adhered surface" are used interchangeably to mean the same thing.

[0051] In addition, the material of the adhesive surface of the "target installation object" includes glass or plastic that has no irregularities or has a high degree of flatness, and examples of plastic include, but are not limited to, polymethyl methacrylate (PMMA), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), polyamide (PA), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), etc.

[0052] Throughout this specification, when a part is described as "comprising" a certain element, this means that it can further include other elements, but not excluding other elements, unless otherwise specified.

[0053] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by an ordinary expert in the technical field to which the present invention belongs. Furthermore, it should be understood that terms used herein should be interpreted to have a meaning consistent with the meaning in the present specification and the related technical field, and should not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0054] As shown in FIG. 3, the present invention provides a light emitting diode 130 film comprising a substrate 100, an electrode layer 110 formed on at least a portion of the substrate 100, a solder 120 formed on at least a portion of the electrode layer 110, a light emitting diode 130 positioned on the solder 120 and connected to the electrode layer 110, a molding layer 140 applied to the entire surface of the substrate 100, the electrode layer 110, and the light emitting diode 130, and a variable adhesive film positioned on the molding layer 140, and characterized in that the light emitting diode 130 film satisfies the following formula 1:

number

[0055] To ensure reliable adhesion of the LED film 10 according to the present invention to the target surface, the thickness A of the molding layer 140 must be greater than or equal to the sum of the thickness B of the solder and the thickness C of the LED. If the thickness A of the molding layer 140 is smaller than the thickness of the LED chip, air bubbles are likely to be generated and trapped during lamination of the variable adhesive film 150, resulting in visual distortion during application and a reduced aesthetic effect. In contrast, if the thickness A of the molding layer 140 is greater than five times the sum of the thickness B of the solder 120 and the thickness C of the LED, the flexibility and stretchability of the LED film 10 may be reduced, increasing the film thickness and reducing durability on targets with curved surfaces. Furthermore, light unevenness may become more pronounced when the LED film 10 is driven.

[0056] 3, in the present invention, the molding layer 140 is applied to cover the entire surface of the substrate 100 on which the electrode layer 110, solder, and light emitting diode are formed. The molding layer 140 is applied to the substrate 100 to cover the entire mounted LED chip, protecting the LED chip from external physical forces and preventing impurities from entering the LED chip. In addition, the manufacturing process of the light emitting diode film 10 according to the present invention is simple and easy, thereby reducing manufacturing costs.

[0057] A variable adhesive film 150 is positioned on the molding layer 140. The variable adhesive film 150 may include a base film 152 and a variable adhesive layer on the base film 152. In this case, the base film 152 is positioned and attached directly on the molding layer 140, and the variable adhesive layer 151 positioned on the base film 152 is subsequently attached to the surface of the target installation object. The base film 152 can prevent damage to the electrode layer 110, solder 120, and light emitting diodes from external forces, and the variable adhesive layer 151 has excellent adhesive reliability and reworkability (see FIG. 5).

[0058] In the present invention, one side of the molding layer 140 is attached to the substrate 100, and the other side is attached to the variable adhesive film 150 located thereon. The molding layer 140 has an adhesive strength of 100 gf / cm or more to both the substrate 100 and the variable adhesive film 150. The molding layer 140 has high adhesive strength, thereby protecting the LEDs and electrodes and providing excellent durability.

[0059] The molding layer 140 has a Young's modulus of 0.05 MPa to 50 MPa, preferably 0.05 to 30, and more preferably 0.08 to 20. If the molding layer 140 has a Young's modulus higher than 50 MPa, flexibility, stretchability, and adhesive application properties may be reduced, and if it is lower than 0.05 MPa, metal wiring, LEDs, etc. located below the molding layer 140 may be physically damaged when exposed to external impact.

[0060] The molding layer 140 may be formed by UV curing a molding liquid, and the molding liquid is applied so that the cured molding layer 140 satisfies the following formula 1:

number

[0061] Even within this thickness range, the molding layer 140 has high transparency and low cure shrinkage, thereby increasing planarization and adhesion to the LED chip, and providing excellent durability and adhesion even when attached to a curved surface.

[0062] The molding liquid has a curing shrinkage rate of 13% or less, preferably 10% or less, during UV curing. A high shrinkage rate (curing shrinkage rate) of the molding liquid during curing can reduce adhesion and cause distortion and warpage due to a step between the LED position and the empty space. Therefore, the curing shrinkage rate of the molding liquid is preferably 13% or less. The molding liquid according to the present invention has a low curing shrinkage rate, which prevents thickness deviations at the LED light source and its surrounding area. This prevents ring-shaped optical distortion and poor adhesion lift-up on the adhered surface when attaching the light-emitting diode film 10 according to the present invention. In the present invention, the molding liquid provides a molding layer 140 with excellent surface planarization over the entire surface of the substrate 100 on which the electrode layer 110, the solder 120, and the light-emitting diode are formed, and high adhesive reliability.

[0063] The viscosity of the molding liquid is in the range of 100 cps to 2,000 cps, preferably 100 to 1500 cps at 23° C. before hardening. Within this range, the coating film of molding layer 140 does not become excessively thick, and can be controlled to a desired thickness.

[0064] The molding layer 140 may be formed of a transparent material to allow light to easily pass through. Preferably, it may be transparent with a transmittance of 80% or more, such as optically transparent resin (OCR). Optically transparent resins (OCR) have low reflection properties, which increases transmittance and improves visibility.

[0065] The molding liquid can be prepared using an optically transparent adhesive resin composition for forming an optically transparent resin (OCR). The optically transparent resin adhesive composition can include one or more oligomers, polymers, and / or derivatives thereof selected from silicone acrylates, acrylates, urethane acrylates, urethanes, butylenes, isobutylenes, and rubbers, as well as a UV initiator and additives. The components of the molding liquid will be described in more detail below, but are not limited thereto, and any optically transparent resin composition widely known for preparing an optically transparent resin (OCR) can be used.

[0066] The weight average molecular weight of the oligomer or polymer may be about 5,000 to 300,000 g / mol.

[0067] <Acrylate oligomer> The acrylate oligomer may include, but is not limited to, one or more oligomers selected from the group consisting of methyl methacrylate, urethane acrylate, epoxy acrylate, silicone acrylate, ethylhexyl acrylate, butyl acrylate, ethyl acrylate, isobornyl acrylate, cyclohexyl methacrylate, glycidyl methacrylate, glycidyl acrylate, behenyl acrylate, ethyl acrylate, lauryl acrylate, stearyl acrylate, acrylic acid, hydroxyethyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, phenoxy acrylate, methyl acrylate, hexanediol diacrylate, and combinations thereof. Preferably, the acrylate oligomer is a urethane acrylate oligomer.

[0068] The acrylate resin may be included in an amount of 20 to 80 wt % of the total weight of the molding liquid. If the weight of the acrylate resin is less than 20 wt %, the cure shrinkage rate of the molding layer increases, and if it exceeds 80 wt %, the durability of the molding layer decreases.

[0069] The weight average molecular weight of the acrylate resin may be about 5,000 to 300,000 g / mol.

[0070] <Isobutylene oligomer> The isobutylene oligomer may be a single oligomer of an isobutylene monomer, an oligomer of another monomer polymerizable with an isobutylene monomer, or a mixture thereof. For example, the isobutylene oligomer may include a monomer of 1-butene, 2-butene, isoprene, styrene, or butadiene.

[0071] The cured resin containing the isobutylene oligomer has very low polarity, is transparent, and is hardly affected by corrosion, and therefore can achieve excellent moisture barrier properties, durability reliability, and optical properties. The isobutylene oligomer may be exemplified by an oligomer of isobutylene and isoprene, an oligomer of isoprene and styrene, an oligomer of butadiene and styrene, an oligomer of isoprene, butadiene and styrene, and an oligomer of polyisoprene, polybutadiene, or isoprene and styrene, an oligomer of butadiene and styrene, or an oligomer of isoprene, butadiene and styrene.

[0072] The isobutylene polymer may be contained in an amount of 10 to 60% by weight based on the total weight of the molding liquid.

[0073] <Rubber> The rubber may have a functional group such as a hydroxyl group or a carboxyl group at its terminal. As an example, the rubber may be a polydiene having a functional group such as a hydroxyl group or a carboxyl group at its terminal. For example, the rubber may be a compound having a polyisoprene skeleton, a polybutadiene skeleton, a styrene-butadiene skeleton, an ethylene-propylene copolymer (EPM), or a terpolymer of ethylene, propylene, and a non-conjugated diene (EPDM), but is not limited to these.

[0074] The weight average molecular weight of the rubber can be appropriately selected within a range that does not impair the object of the present application, and may be, for example, in the range of about 1,000 to 200,000 g / mol, about 1,000 to 150,000 g / mol, or about 2,000 to 100,000 g / mol.

[0075] The rubber may be contained in an amount of 10 to 60% by weight based on the total weight of the molding liquid.

[0076] <Acrylate monomer> The optically transparent resin adhesive composition may further include an acrylate monomer.

[0077] The high molecular weight oligomers and polymers can be diluted to adjust viscosity, and the required modulus, adhesion, and polarity can be adjusted to prevent cloudiness during high-temperature and high-humidity testing. Monofunctional and multifunctional acrylate monomers can be used. The shrinkage rate, curing reaction speed, and durability of the molding layer can be adjusted using a UV curing reaction.

[0078] The acrylate monomer may be contained in an amount of 20 to 90 wt %, preferably 20 to 80 wt %, and more preferably 30 to 70 wt %, based on the total weight of the molding liquid. If it is contained in an amount less than 30 wt %, it is difficult to adjust the viscosity of the composition liquid, and if it is contained in an amount greater than 70 wt %, it is difficult to control the cure shrinkage and the cure reaction rate. Any structure may be applied as long as it is compatible with the oligomer or polymer used and has a configuration that satisfies the required physical properties.

[0079] <Photoinitiator> The photoinitiator generates active radicals when irradiated with ultraviolet light of a specific wavelength range, and the generated radicals induce a photopolymerization reaction of the reactive acrylate oligomer or monomer. The photoinitiator may be a ketone-based photoinitiator or a phosphine-based photoinitiator.

[0080] Examples of the ketone-based photoinitiator include, but are not limited to, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), 2-isopropylthioxanthone (ITX), 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, and the like.

[0081] The photoinitiator may be contained in an amount of 0.01 to 2% by weight based on the total weight of the molding liquid.

[0082] <Additives> The additives may include optional conventional additives such as reactive diluents, scattering agents, adhesion promoters, surfactants, fillers, coupling agents, silanes, wetting agents, plasticizers, release agents, crosslinking agents, catalysts, curing agents, wetting agents, UV stabilizers, heat stabilizers, and rust inhibitors. The molding liquid may also contain other solvents as additives, but solventless molding is preferred. The reactive diluents and plasticizers may each be included in an amount of 1 to 10 wt % based on the total weight of the molding liquid. The total amount of other additives, excluding the reactive diluents and plasticizers, may be appropriately included in an amount of 0.01 to 5 wt % based on the total weight of the molding liquid.

[0083] Solvents, which are volatile organic compounds, are harmful to the human body and cause environmental pollution. Furthermore, conventional processes have drawbacks, such as reduced productivity of molding solutions due to the need for a drying oven to volatilize the solvent. However, the solvent-free molding solution of the present invention not only solves the problems of toxicity and environmental pollution, but also improves productivity by eliminating the drying process used to volatilize the solvent. Furthermore, since shrinkage due to solvent evaporation does not occur, the curing shrinkage rate of the molding layer is reduced.

[0084] In one embodiment of the present invention, the molding liquid may contain organic or inorganic dyes and pigments to improve contrast and impart optical properties. The scattering agent may include inorganic scattering particles such as SiO2, TiO2, and ZrO2, organic scattering particles, light-absorbing particles, or a combination thereof.

[0085] In one embodiment of the present invention, the variable adhesive film 150 located on the molding layer 140 adheres to the surface to be adhered, allowing the LED film to be attached to the target object.

[0086] In one embodiment of the present invention, the variable adhesive film 150 may include a base film 152 and a variable adhesive layer 151 on the base film 152. In this case, the base film 152 is directly positioned and attached to the molding layer 140, and the variable adhesive layer 151 positioned on the base film 152 is subsequently attached to the surface of the target installation object.

[0087] In one embodiment of the present invention, the variable adhesive layer 151 of the variable adhesive film 150 satisfies the value A of 1 or more according to the following formula 2 with respect to the surface to be adhered.

number

[0088] After the variable adhesive layer 151 is attached to the target surface of the installation object, the adhesive strength (A1) to the target surface measured at room temperature after 30 minutes is 50 gf / in or less.

[0089] After the variable adhesive layer 151 is attached to the target surface, the adhesive strength (A2) of the variable adhesive layer 151 to the target surface measured at room temperature after 1,000 hours exceeds 50 gf / in.

[0090] When the value A in Equation 1 is 1 or more, the variable adhesive film 150 has excellent wettability, removability, and adhesive reliability on the target surface. In particular, it can be attached without defects such as air bubbles, can be removably attached to surfaces such as plastic or glass, has excellent peeling strength and workability, and can prevent peeling or lifting after complete adhesion.

[0091] The base film 152 of the variable adhesive film 150 may include, but is not limited to, a polymer resin selected from the group consisting of polyethylene terephthalate (PET), polycarbonate (PC), polyethylene (PE), polyurethane (PU), polyimide (PI), cyclic olefin polymer (COP), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyamide (PA), polycyclohexylene dimethylene terephthalate (PCT), and polypropylene (PP), or an alloy resin thereof. The thickness of the base film 152 may be 50 μm to 150 μm, preferably 50 μm to 100 μm.

[0092] The variable adhesive layer 151 of the variable adhesive film 150 can be manufactured from a pressure-sensitive adhesive composition, and the pressure-sensitive adhesive composition can include a urethane resin composition containing a urethane resin as a main component, an interfacial modifier, and an adhesion enhancer.

[0093] In one embodiment of the present invention, the weight ratio of the interface modifier to the adhesion enhancer in the pressure-sensitive adhesive composition (interface modifier / adhesion enhancer) may be 0.8 or less. When this range is satisfied, the variable adhesive film 150 has excellent wettability, removability, and adhesive reliability with respect to the target surface of the installation object.

[0094] The variable adhesive layer 151 contains both the interfacial modifier and the adhesion enhancer, thereby simultaneously achieving removability and adhesion stability to a receiving surface such as plastic or glass. The variable adhesive layer 151 manufactured from the pressure-sensitive adhesive composition exhibits low adhesion and excellent removability immediately after attachment to a receiving surface due to the distribution and presence of the interfacial modifier in the variable adhesive layer 151 on the receiving surface. However, over time, rearrangement of the interfacial modifier and the adhesion enhancer occurs, resulting in increased adhesion due to the interaction between the adhesion enhancer and the receiving surface, thereby providing adhesion stability. Ultimately, the present invention provides a light-emitting diode film 10 with excellent wettability, removability, and adhesive reliability through the variable adhesive layer 151.

[0095] The variable adhesive film 150 may include a release film 200 on the variable adhesive layer 151 before being attached to the target surface.

[0096] The release film 200 exhibits hydrophobicity in order to have release properties relative to the variable adhesive layer 151, but the receiving surface, such as plastic or glass, exhibits hydrophilic properties compared to the release film 200. Therefore, when the release film 200 on the variable adhesive layer 151 is removed and the variable adhesive layer 151 is attached to the receiving surface of the target, the hydrophobic groups of the interface modifier present in the variable adhesive layer 151 are oriented to the receiving surface immediately after attachment, resulting in low adhesive strength. However, over time, the hydrophobic and hydrophilic groups of the interface modifier in the variable adhesive layer 151 are rearranged in equilibrium with the receiving surface, such as plastic or glass, which is relatively more hydrophilic than the release film 200, and ultimately the adhesion enhancer reacts with the receiving surface, increasing the adhesive strength.

[0097] The urethane resin composition, the interface modifier, and the adhesion enhancer contained in the variable adhesive layer 151 may be, but are not limited to, the following materials.

[0098] <Urethane resin composition> The urethane resin composition contains, as a main component, a urethane resin obtained by curing a urethane prepolymer obtained by reacting a polyol with a polyfunctional isocyanate compound in the presence of a catalyst.

[0099] The polyol may contain one type of polyol, or more preferably, two or more types of polyol. In this case, one of the two or more types of polyol contains a polyol having three or more OH groups, and examples thereof can be selected from the group consisting of polyester polyols, polyether polyols, polycaprolactone polyols, polycarbonate polyols, and castor oil-based polyols. Such polyol components can exhibit excellent reworkability, such as reduced residue.

[0100] The polyester polyol can be obtained by an esterification reaction between a polyol component and an acid component. Examples of the polyol component can be selected from the group consisting of ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,8-decanediol, octanedecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, and polypropylene glycol. Examples of the acid component that can be used include succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, dimer acid, 2-methyl-1,4-cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenylcarboxylic acid, and acid anhydrides thereof.

[0101] Polyether polyols can be obtained by addition polymerization of an alkylene oxide selected from ethylene oxide, propylene oxide, or butylene oxide using water, a low-molecular-weight polyol (such as propylene glycol, ethylene glycol, glycerin, trimethylolpropane, or pentaerythritol), a bisphenol (such as bisphenol A), or a dihydroxybenzene (such as catechol, resorcinol, or hydroquinone) as an initiator. Specific examples include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0102] The polycaprolactone polyol is a caprolactone-based polyester diol obtained by ring-opening polymerization of a cyclic ester monomer such as ε-caprolactone or σ-valerolactone. Examples thereof include polycarbonate polyols obtained by polycondensation of the polyol component with phosgene, polycarbonate polyols obtained by transesterification and condensation of the polyol component with a carbonate diester such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethyl butyl carbonate, ethylene carbonate, propylene carbonate, diphenyl carbonate, or dibenzyl carbonate, copolymer polycarbonate polyols obtained by combining two or more of the polyol components, polycarbonate polyols obtained by esterification of the various polycarbonate polyols with a carboxyl group-containing compound, and various polycarbonate polyols. polycarbonate polyols obtained by subjecting the above-mentioned various polycarbonate polyols to an etherification reaction with a hydroxyl group-containing compound; polycarbonate polyols obtained by subjecting the above-mentioned various polycarbonate polyols to an ester exchange reaction with an ester compound; polycarbonate polyols obtained by subjecting the above-mentioned various polycarbonate polyols to an ester exchange reaction with a hydroxyl group-containing compound; polyester-based polycarbonate polyols obtained by subjecting the above-mentioned various polycarbonate polyols to a polycondensation reaction with a dicarboxylic acid compound; and copolymerized polyether-based polycarbonate polyols obtained by copolymerizing the above-mentioned various polycarbonate polyols with an alkylene oxide.

[0103] The castor oil-based polyol is a castor oil-based polyol obtained by reacting a castor oil fatty acid with the polyol component.

[0104] As another component for producing the urethane resin, the polyfunctional isocyanate compound may be selected from polyfunctional aliphatic isocyanate compounds, polyfunctional alicyclic isocyanate compounds, polyfunctional aromatic diisocyanate compounds, and trimers having an isocyanurate ring, and may be used alone or in a mixed form.

[0105] A preferred example of the polyfunctional aliphatic isocyanate compound is one that can be selected from the group consisting of trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0106] Furthermore, examples of polyfunctional alicyclic isocyanate compounds include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated tetramethylxylylene diisocyanate. The polyfunctional aromatic diisocyanate compound can be selected from the group consisting of phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, and xylylene diisocyanate.

[0107] The polyol and the multifunctional isocyanate compound are reacted in the presence of a catalyst to produce a urethane prepolymer having a hydroxyl group terminal, and then a three-dimensional network structure can be formed using a multifunctional isocyanate having two or more functional groups as a curing agent.

[0108] Other examples of the polyfunctional isocyanate compound that can be used include trimethylolpropane adducts of the various polyfunctional isocyanate compounds mentioned above, biurets obtained by reacting them with water, and trimers having an isocyanurate ring, and these may be used in combination.

[0109] As described above, the urethane resin is obtained by curing a composition containing a polyol and a polyfunctional isocyanate compound. Such a composition may contain, within the scope of the present invention, an antistatic agent, a catalyst, resin components other than the urethane resin, a tackifier, an inorganic filler, an organic filler, a metal powder, a pigment, a softener, a plasticizer, an antioxidant, a conductive agent, an antioxidant, a UV absorber, a light stabilizer, a surface lubricant, a leveling agent, a corrosion inhibitor, a heat stabilizer, a polymerization inhibitor, a lubricant, a solvent, and the like, and more preferably, may contain an anti-deterioration agent such as an antistatic agent, an antioxidant, a UV absorber, or a light stabilizer.

[0110] <Interfacial adjuster> Interfacial modifiers are compounds that have both hydrophilic (water-soluble) and hydrophobic (oil-soluble) properties within a single molecule. Hydrophilicity refers to the property of easily bonding with water molecules. Conversely, hydrophobicity refers to the property of having a weak affinity for water.

[0111] In the present invention, the surface conditioner may be a silicone-based nonionic surface conditioner.

[0112] The silicone-based nonionic surface conditioner may be a modified polydimethylsiloxane (e.g., alkyl-modified, phenyl-modified, amino-modified, polyether-modified, and polyoxyalkylene-modified polydimethylsiloxane), organosilicone, polyalkylene-modified heptamethyltrisiloxane, polyalkyleneoxide-modified dimethylpolysiloxane, polyalkyleneoxide-modified heptamethyltrisiloxane, polyalkyleneoxide-modified heptamethylsiloxane, polyether-polymethylsiloxane-copolymer, polyethoxylated dimethylsiloxane ... The silicone-based nonionic surfactant may be, but is not limited to, one or more selected from the group consisting of poly(alkylene oxide), poly(methylsiloxane copolymer), poly(oxypropylene-polyoxyethylene block copolymers), and silicone-polyether copolymer. In a preferred embodiment, the silicone-based nonionic surfactant is a poly(alkylene oxide)-modified silicone having a structure in which a polyethylene oxide / poly(propylene oxide) polar block is grafted onto a silicone backbone, and may be a polyethylene oxide-modified dimethylpolysiloxane or a poly(propylene oxide)-modified dimethylpolysiloxane.Preferably, the polyalkylene oxide-modified silicone may be one containing the polyethylene oxide and polypropylene oxide, and in this case, the ends of the polyethylene oxide and polypropylene oxide may be capped with an alkyl group such as a methyl group or a butyl group. If the ends of the polyethylene oxide and polypropylene oxide are not capped with an alkyl group, the hydroxyl generated by the reaction can chemically react with the urethane resin of the adhesive, preventing rearrangement of the interface conditioner on the surface to be adhered.

[0113] The silicone-based nonionic surface modifier is preferably used in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the urethane resin. If the silicone-based nonionic surface modifier is used in an amount less than 0.01 part by weight, the amount of surface modifier at the interface of the adhesive in contact with the release film 200 is insufficient, resulting in increased adhesive strength and poor reworkability. If the amount is more than 5 parts by weight, the amount of surface modifier at the interface of the adhesive is too high, taking too long to achieve equilibrium in rearrangement, resulting in poor adhesive strength and poor adhesion reliability.

[0114] The silicone-based nonionic surface conditioner has a hydrophilic lipophilic balance (HLB) value of 4 to 8. It was found that when the silicone-based nonionic surface conditioner has an HLB value of 4 to 8, the hydrophilic groups of the surface conditioner are oriented toward the adhered surface over time after the adhesive is attached to the adherend surface, resulting in a gradual increase in adhesive strength. On the other hand, if the HLB value is less than 4, the adhesive is close to hydrophobic (lipophilic), and no rearrangement occurs within the adhesive toward the adhered surface, making it difficult to increase adhesive strength. If the HLB value exceeds 8, the adhesive is close to hydrophilic, and no rearrangement occurs within the adhesive, so adhesive strength does not increase and adhesion reliability is poor.

[0115] <Adhesion enhancer> In the present invention, the adhesion promoter may be a silane coupling agent. In one embodiment, the adhesion promoter may be vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-ethoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, or the like.

[0116] The adhesion enhancer is preferably used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the urethane resin. If the adhesion enhancer is contained in an amount less than 0.1 part by weight, the adhesive strength does not increase after adhering to the adherend surface, resulting in poor adhesion reliability. If the amount is more than 10 parts by weight, problems arise in that the adherend surface may be destroyed and adhesive residue may be left behind when peeling is required after a certain period of time has passed.

[0117] In one embodiment of the present invention, the pressure-sensitive adhesive composition has a weight ratio (a / b) of the interface modifier (a) to the adhesion enhancer (b) of 0.8 or less. The weight ratio (a / b) of the interface modifier (a) to the adhesion enhancer (b) is preferably 0.7 or less, and more preferably 0.5 or less. If the weight ratio (a / b) of the interface modifier (a) to the adhesion enhancer (b) exceeds 0.8, the adhesive strength does not increase over time, resulting in very low adhesion reliability.

[0118] In one embodiment of the present invention, the light emitting diode film 10 includes a substrate 100, an electrode layer 110 formed on at least a portion of the substrate 100, a solder 120 formed on at least a portion of the electrode layer 110, a light emitting diode positioned on the solder 120 and connected to the electrode layer 110, a molding layer 140 applied to cover the entire surfaces of the substrate 100, the electrode layer 110, and the light emitting diode, and a variable adhesive film 150 positioned on the molding layer 140. A protective film 170 may also be included under the other surface of the substrate 100 on which the electrode layer 110 is formed (see FIG. 4). The protective film functions to prevent physical damage to the light emitting diode film 10 from external impact.

[0119] The protective film 170 is located under the other surface of the substrate 100 on which the electrode layer 110 is formed. For example, the protective film 170 may be located directly under the substrate 100, or another member may be present between the substrate 100 and the protective film 170.

[0120] In one embodiment of the present invention, the protective film 170 may include an adhesive layer 171, a base layer 172, and a protective coating layer 173. In this case, the adhesive layer 171 is disposed facing the substrate, and the protective coating layer 173 is disposed at the outermost corner of the lower part of the substrate in the final LED film 10.

[0121] In one embodiment of the present invention, only a protective coating layer 173 may be attached to the lower surface of the substrate 100 on one side of which the electrode layer is formed. The protective coating layer 173 may be directly located on the lower surface of the substrate 100, or another member may be present between the substrate 100 and the protective coating layer 173.

[0122] In one embodiment of the present invention, the adhesive layer 171 and the protective coating layer 173 may be manufactured using an adhesive composition prepared with a suitable base resin such as an acrylic resin, an epoxy resin, a urethane resin, or an ester resin, but are not limited thereto and may be manufactured using a commonly used adhesive composition.

[0123] One or more layers of the adhesive layer 171, the substrate layer 172 and the protective coating layer 173 in the protective film 170 may contain a base resin as well as commonly used additives, for example, light absorbing, light blocking or light scattering materials, thereby providing light absorbing, light blocking or light scattering functions.

[0124] The protective coating layer 173 may contain commonly added additives in addition to the resins listed above, as long as the effects of the present invention are not impaired. For example, the protective coating layer 173 may contain a light absorbing, light blocking, and / or light scattering material, thereby providing light absorbing, light blocking, and / or light scattering functions.

[0125] In another embodiment of the present invention, the substrate 100 may have a light absorbing, light blocking or light scattering function, and / or one or more layers of the base film 152 and the variable adhesive layer 151 in the variable adhesive film 150 may have a light absorbing, light blocking or light scattering function. In this case, the transmittance of the variable adhesive film may be 30 to 80%. In the present invention, when one or more layers included in the light emitting diode film 10 have a light absorbing, light blocking or light scattering function, one or more layers may contain a commonly used light absorbing, light blocking or light scattering material.

[0126] In one embodiment of the present invention, in order to improve the contrast ratio of the light emitting diode film 10, a contrast ratio improving layer 190 may be disposed directly below the other surface of the substrate 100 on which the electrode layer 110 is formed. The contrast ratio improving layer 190 may be formed by coating and drying a black resin composition containing a light absorbing material such as carbon black on the substrate, or may be in the form of a sheet, plate, film, etc. Examples of the light absorbing material include carbon black, titanium black such as low-order titanium oxide or titanium oxynitride, metal oxides such as iron oxide, and other organic pigment mixtures.

[0127] The brightness ratio improving layer 190 has an opaque or translucent optical property by being black or colored. In addition, the brightness ratio improving layer 190 has a pattern according to the transmittance, thereby providing a light emitting diode with improved optical properties. For example, the black resin composition may be applied to a substrate and dried to form a black coating, and the brightness ratio improving layer 190 may be finely patterned using a photolithography method.

[0128] As shown in FIG. 4, in one embodiment of the present invention, a construction protection film 180 is included at the bottom of the substrate 100 to prevent damage to the product during the process, and the construction protection film 180 is removed after the manufacturing process.

[0129] The light emitting diode film 10 according to the present invention has a yellowness index (b*) of Δ5 or less after a light resistance test. If the yellowness index of the light emitting diode film 10 exceeds Δ5, the transparency of the entire film decreases, so the yellowness index (b*) after the light resistance test must satisfy Δ5 or less. Therefore, the light emitting diode film 10 has high transparency and visible light transmittance, and can simultaneously achieve a desired neutral color and excellent light resistance. [Example]

[0130] The present invention will be described in more detail with reference to preferred examples thereof below, but the scope of the present invention is not limited to the following examples.

[0131] Light-emitting diode film manufacturing After printing solder paste on the terminals of a mesh-type transparent electrode substrate formed with a Ni-Cu laminated structure on 188 μm PET, an LED was mounted using a chip mounting device and reflowed to a peak temperature of 180°C, preparing a film-type LED substrate.

[0132] Then, the molding solution prepared in the following Examples and Comparative Examples was applied to a film-type LED substrate prepared in advance, and except for Comparative Example 7, the variable adhesive layer of the variable adhesive film prepared by the following method was brought into contact with and attached to the applied molding layer so that it faced the molding layer, and then the molding layer was cured by UV irradiation to obtain a light-emitting diode film.

[0133] <Manufacturing variable adhesive film> A variable pressure-sensitive adhesive composition was prepared by blending 100 parts by weight of a hydroxy-terminated urethane prepolymer (weight average molecular weight 80,000) with 6 parts by weight of a multifunctional hexamethylene diisocyanate crosslinker, adding 0.01 parts by weight of the catalyst dibutyltin dilaurate (DBTDL), 0.3 parts by weight of HBL7 polypropylene oxide / polyethylene oxide (20 / 80) polydimethylsiloxane, and 2 parts by weight of 3-methacryloylpropyltrimethoxysilane, diluting with methyl ethyl ketone (MEK) to a solids content of 50% by weight, mixing, and degassing. The resulting variable pressure-sensitive adhesive composition was applied to a PET substrate film and dried in an oven at 120°C for 3 minutes to produce a 100 μm thick adhesive layer.

[0134] <Molding fluid manufacturing> Example 1: A molding liquid was prepared by homogenizing 30 gr of urethane acrylic oligomer SC2404 (Miwon), 20 gr of isobornyl acrylate, 40 gr of ethylhexyl acrylate, 10 gr of trimethylolpropane triacrylate, and 1 gr of Irgacure 651. The molding solution was used to obtain a light emitting diode film by the method described above. In this example, the thickness A of the molding layer 140 was 1.5 times the total height of the solder thickness B and the LED thickness C.

[0135] Example 2: A light-emitting diode film was obtained by the method of Example 1, except that the molding liquid was prepared by homogenizing 20 gr of polyisobutylene BASF OPPANOL B15N, 50 gr of isobornyl acrylate, 15 gr of ethylhexyl acrylate, 15 gr of tricyclodecane dimethanol diacrylate, and 1 gr of Irgacure 651.

[0136] Example 3: A light-emitting diode film was obtained by the method of Example 1, except that a basket mill was used to disperse 3g of zirconia (ZrO2) having an average particle size of 1 μm into the molding liquid of Example 1 so that a scattering agent was included.

[0137] Example 4: A light-emitting diode film was obtained by the method of Example 1, except that 0.5 gr of carbon black having an average particle size of 25 nm was dispersed in the molding liquid of Example 1 using a basket mill to contain particles capable of adjusting transmittance.

[0138] Comparative Example 1: A light-emitting diode film was obtained by the method of Example 1, except that the thickness A of the molding layer was set to 0.8 times the total height of the thickness B of the solder and the thickness C of the LED.

[0139] Comparative Example 2: A light-emitting diode film was obtained by the method of Example 1, except that the thickness A of the molding layer was set to 5.2 times the total height of the thickness B of the solder and the thickness C of the LED.

[0140] Comparative Example 3: A molding solution was prepared by homogenizing 10 gr of urethane acrylic oligomer SC2404 (Miwon), 10 gr of isobornyl acrylate, 75 gr of ethylhexyl acrylate, 5 gr of trimethylolpropane triacrylate, and 1 gr of Irgacure 651. The resulting molding solution was used to prepare an LED film using the method described above. In this example, an LED film was obtained in which the molding layer thickness A was 0.8 times the total height of the solder thickness B and the LED thickness C.

[0141] Comparative Example 4: A light-emitting diode film was obtained by the method of Comparative Example 3, except that the thickness A of the molding layer was 5.2 times the total height of the thickness B of the solder and the thickness C of the LED.

[0142] Comparative Example 5: A molding solution was prepared by homogenizing 40 gr of acrylic urethane oligomer SC2404 (Miwon), 30 gr of isobornyl acrylate, 10 gr of ethylhexyl acrylate, 20 gr of trimethylolpropane triacrylate, and 1 gr of Irgacure 651. The resulting molding solution was used to prepare an LED film using the method described above. In this example, an LED film was obtained in which the molding layer thickness A was 0.8 times the total height of the solder thickness B and the LED thickness C.

[0143] Comparative Example 6: A light-emitting diode film was obtained by the method of Comparative Example 5, except that the thickness A of the molding layer was 5.2 times the total height of the thickness B of the solder and the thickness C of the LED.

[0144] Comparative Example 7: A light-emitting diode film was obtained by the same method as in Example 1, except that the molding solution of Example 1 was used and a release film made of PET material was attached onto the molding layer instead of the variable adhesive film.

[0145] Experimental example: Performance evaluation of light-emitting diode film The performance of the transparent LED film panels manufactured in the examples and comparative examples was evaluated by the following methods.

[0146] 1. Measurement of molding layer shrinkage rate After application of the molding liquids of the Examples and Comparative Examples, the densities of the molding liquid (liquid) before UV curing and the molding layer (solid) after UV curing were measured and substituted into the following equation to calculate the shrinkage rate. Molding liquid shrinkage rate = (1 / density after hardening - 1 / density before hardening) / (1 / density before hardening)*100

[0147] 2. Tensile strength (Young's modulus and elongation rate) The molding solution prepared in the examples and comparative examples was applied and cured to obtain a molding layer with a thickness of 1.3 mm, and the molding layer sample was cut to a length of 60 mm and a width of 15 mm. The cut specimen was fixed to the upper and lower jigs of a universal testing machine (UTM) at a distance of 25 mm, and the specimen was stretched at a rate of 100 mm / min. The stress corresponding to the strain until the specimen was broken was measured, and the Young's modulus was calculated.

[0148] -Young's modulus (E'): The ratio of stress to strain in the range of deformation rate 0.3% to 1%

number

[0149] 3. Measurement of total light transmittance and haze value The molding layers manufactured in the examples and comparative examples were measured for total light transmittance in the range of 380 to 760 nm according to JIS K 7105 standard, and the haze was measured using NDH-7000 (Nippon Denshoku Co., Ltd.).

[0150] 4. Push Test The variable adhesive film of the light-emitting diode film prepared in Examples 1 to 4 and Comparative Examples 1 to 6 was attached to glass or a SUS plate, with the transparent substrate positioned on top. In Comparative Example 7, the molding layer of the branched light-emitting diode film was attached to glass or a SUS plate, with the transparent substrate positioned on top. After driving the light-emitting diode film to emit light, a push-pull gauge was used to apply pressure to the LED using a 5 mm diameter probe to measure the LED's drop force. The pass / fail criteria was set at 3 kgf.

[0151] 5.Adhesive workability The LED films manufactured in the examples and comparative examples were prepared in a size of 430 x 600 mm, and the molding layer or variable adhesive film of the LED film was attached to the surface of the glass material using a wool spatula without generating any air bubbles. The adhesion workability of each of the examples and comparative examples was evaluated according to the following criteria.

[0152] Good O: No trapped air bubbles, no side spreading after application -Excellent performance in the re-detachment and re-attachment process for repositioning after attachment Bad X: - Check bubble generation and trapping phenomenon -Poor re-detachment and re-attachment to re-delineate the position after attachment

[0153] [Table 1]

[0154] As shown in Table 1 above, Examples 1 to 4 all exhibited good adhesion, workability and durability.

[0155] In contrast, Comparative Examples 1 to 6 did not satisfy the above formula 1 (1*(B+C)≦A≦5*(B+C), where A is the height of the molding layer measured from the substrate, B is the thickness of the solder, and C is the thickness of the light-emitting diode).

[0156] As a result, in Comparative Example 1, air bubbles were trapped during the lamination process of the variable adhesive film, causing lifting, and the thickness uniformity and flatness of the molding layer and variable adhesive film corresponding to the location of the LED chip were poor. This resulted in poor adhesion and durability of the light-emitting diode. In Comparative Example 2, the molding layer did not satisfy equation 1 (1*(B+C)≦A≦5*(B+C) (where A is the height of the molding layer measured from the substrate, B is the solder thickness, and C is the thickness of the light-emitting diode). This resulted in wiring cracks even with a low force of 2.5 in the push test, and twisting of the molding layer occurred, resulting in poor adhesion and durability due to the lifting phenomenon. In addition, the push test result was less than 3 kgf, confirming insufficient durability.

[0157] In the cases of Comparative Examples 3 and 4, the adhesion workability was poor, and the Young's modulus of the molding layer was measured at 0.03, lower than 0.05. In particular, in the case of Comparative Example 4, the result of the push test was measured at a very low value of 1.1 Kf, and the wiring, solder cracks, LEDs, etc. were damaged by external impact, pressure, and bending deformation forces, resulting in poor durability.

[0158] In Comparative Examples 5 and 6, the shrinkage rate of the molding layer was as high as 15%, and the Young's modulus was measured at 120 MPa, confirming that flexibility, stretchability, and adhesive properties were reduced. When the Young's modulus was high as in Comparative Examples 5 and 6, the shrinkage rate of the molding layer exceeded 10-13%, and in this case, even if a slight curl was formed on the surface of the LED film to be adhered during attachment, lifting occurred, resulting in reduced attachment workability.

[0159] In the case of Comparative Example 7, which did not include a variable adhesive film, the re-adhesion adhesive strength and the resulting adhesive workability were poor. [Explanation of symbols]

[0160] 10: Light-emitting diode film, 20: Target installation object 100: substrate, 110: electrode layer, 120: solder 130: light-emitting diode, 140: molding layer, 150: variable adhesive film 151: Variable adhesive layer, 152: Base film, 200: Release film 170: Protective film, 171: Adhesive layer, 172: Base material layer 173: protective coating layer, 180: protective film for construction, 190: contrast improvement layer A: Height of molding layer, B: Height of solder, C: Thickness of light-emitting diode

Claims

1. A substrate; an electrode layer formed on at least a portion of the substrate; a solder formed on at least a portion of the electrode layer; a light emitting diode located on the solder and connected to the electrode layer; a molding layer applied to the entire surface of the substrate, the electrode layer, and the light emitting diode; a variable adhesive film positioned on the molding layer; The molding layer is formed by UV curing a molding liquid, The molding liquid has a cure shrinkage rate of 13% or less, A light-emitting diode film characterized by satisfying the following formula 1: [Equation 1]

2. The light-emitting diode film according to claim 1 , wherein the molding layer has an adhesive strength of 100 gf / cm or more to the substrate and the variable adhesive film, respectively.

3. 2. The light-emitting diode film according to claim 1, wherein the molding layer has a Young's modulus of 0.05 to 50 MPa.

4. 2. The light-emitting diode film according to claim 1, wherein the viscosity of the molding liquid ranges from 100 cps to 2,000 cps.

5. 2. The light-emitting diode film according to claim 1, wherein the molding liquid comprises an oligomer or polymer selected from one or more oligomers, polymers, and / or derivatives thereof selected from silicone acrylates, acrylates, urethane acrylates, urethanes, butylenes, isobutylenes, and rubbers, a UV initiator, and an additive.

6. The light-emitting diode film according to claim 5 , wherein the molding liquid additionally comprises inorganic scattering particles, organic scattering particles, light-absorbing particles, or a combination thereof.

7. The light-emitting diode film according to claim 5 , wherein the molding liquid is solvent-free.

8. The variable adhesive film includes a base film and a variable adhesive layer on the base film, The light-emitting diode film according to claim 1 , wherein the substrate film is located directly on the molding layer.

9. The light-emitting diode film according to claim 8 , wherein the variable adhesive layer adheres to a target surface to be attached.

10. The light-emitting diode film according to claim 9 , wherein the variable adhesive layer has an A value of 1 or more as adhesive strength to the surface to be adhered. [Equation 2]

11. The light-emitting diode film according to claim 10, wherein the adhesive strength (A1) of the variable adhesive layer to the surface to be adhered is 50 gf / in or less.

12. 11. The light-emitting diode film according to claim 10, wherein the adhesive strength (A2) of the variable adhesive layer to the surface to be adhered is greater than 50 gf / in.

13. The light emitting diode film according to claim 9, wherein the surface to be adhered is made of glass or plastic material.

14. 9. The light-emitting diode film according to claim 8, wherein the variable adhesive layer is a pressure-sensitive adhesive.

15. The light-emitting diode film of claim 8 , further comprising a release film on the variable adhesive layer.

16. 9. The light-emitting diode film according to claim 8, wherein the thickness of the variable adhesive layer is 50 to 150 μm.

17. The light-emitting diode film according to any one of claims 1 to 16, wherein the substrate has a light-absorbing, light-blocking or light-scattering function.

18. The light-emitting diode film according to any one of claims 8 to 16, wherein one or more layers of the base film and the variable adhesive layer in the variable adhesive film have a light-absorbing, light-blocking or light-scattering function.

19. 19. The light-emitting diode film according to claim 18, wherein the transmittance of the variable adhesive film is 30-80%.

20. The light emitting diode film according to any one of claims 1 to 16, further comprising a protective film or protective coating layer under the other surface of the substrate having the electrode layer formed on one surface thereof.

21. The light emitting diode film of claim 20 , wherein the protective film includes an adhesive layer, a base layer, and a protective coating layer, and the adhesive layer is disposed opposite the substrate.

22. 21. The light-emitting diode film as claimed in claim 20, wherein the protective coating layer has a light-absorbing, light-blocking or light-scattering function.

23. 22. The light-emitting diode film according to claim 21, wherein one or more of the adhesive layer, the substrate layer and the protective coating layer have a light-absorbing, light-blocking or light-scattering function.

24. 17. The light emitting diode film according to claim 1, further comprising a brightness ratio improving layer directly provided on a lower surface of the other surface of the substrate on which the electrode layer is formed.

25. The light-emitting diode film according to any one of claims 1 to 16, comprising a protective film for installation at the bottom of the substrate.

26. 17. The light-emitting diode film according to claim 1, wherein the yellowness index (b*) after a light resistance test is Δ5 or less.

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