Display device and method of manufacturing the same

Abstract

A display device includes: a plurality of unit modules; and a cover configured to support the plurality of unit modules. Each of the plurality of unit modules includes: a substrate; a plurality of inorganic light emitting diodes disposed on a mounting surface of the substrate; and an encapsulation layer formed on the mounting surface of the substrate to cover the plurality of inorganic light emitting diodes and the mounting surface of the substrate. The encapsulation layer includes a viscoelastic material having viscoelasticity that changes based on a temperature applied to the viscoelastic material.

Description

Technical Field

[0001] The present disclosure relates to a display device capable of directly displaying an image by coupling a plurality of modules to each other, wherein each of the plurality of modules including a self-luminous inorganic light emitting diode is mounted on a substrate, and a method of manufacturing the same. Background Art

[0002] A display device is a type of output device that visually displays information such as characters, graphics, and images. The demand for high brightness, high resolution, large size, high efficiency, and low power display devices is increasing. Therefore, organic light emitting diode (OLED) panels have become increasingly popular as new display devices to replace liquid crystal displays (LCDs). However, OLED panels have some limitations, such as high prices caused by low production yields, low reliability of large-size panels, and durability affected by external environments such as water.

[0003] Considering the known limitations of LCD panels and OLED panels and to complement them, research has been conducted to develop new technologies for manufacturing panels by directly mounting inorganic light-emitting diodes that emit red (R), green (G), and blue (B) light on substrates.

[0004] Inorganic light emitting display technology has its own challenges in transferring very small-sized inorganic light emitting diodes (having sizes of several micrometers to hundreds of micrometers) from a wafer to a substrate. In addition, even after the inorganic light emitting diodes are installed, there are still challenges in physically protecting the inorganic light emitting diodes without affecting the display with optical distortion and optical loss. Even further, a technology is needed that can improve image quality in addition to simply protecting the image. Summary of the invention

[0005]

Technical issues

[0006] One aspect of the present disclosure is to provide a packaging technology that can physically protect inorganic light emitting diodes having a size of several microns to several hundred microns and improve image quality after transferring inorganic light emitting diodes having a size of several microns to several hundred microns from a wafer to a substrate, a manufacturing method of a display device including the packaging technology, and a display device according to the packaging technology.

[0007] Another aspect of the present disclosure is to provide a packaging technology capable of preventing seams between adjacent unit modules from being seen when a large screen is realized by arranging the unit modules in a matrix, a method for manufacturing a display device including the packaging technology, and a display device according to the packaging technology.

[0008] Another aspect of the present disclosure is to provide a packaging technology capable of easily repairing a defective inorganic light emitting diode even after packaging a plurality of inorganic light emitting diodes, and a display device including the packaging technology.

[0009] Additional aspects of the disclosure will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the disclosure.

[0010]

Technical solution

[0011] According to one aspect of the present disclosure, a method for manufacturing a display device includes: mounting a plurality of inorganic light emitting diodes on a mounting surface of a substrate; forming an encapsulation layer including a viscoelastic material on the mounting surface of the substrate to cover the plurality of inorganic light emitting diodes and the mounting surface of the substrate; assembling a plurality of unit modules including a first unit module and a second unit module adjacent to each other, each of the plurality of unit modules including a substrate, a plurality of inorganic light emitting diodes, and an encapsulation layer, the first unit module and the second unit module having a gap disposed between the first unit module and the second unit module; and changing the viscoelasticity of a first encapsulation layer of the first unit module and a second encapsulation layer of the second unit module to visually hide a seam. Mounting the plurality of inorganic light emitting diodes may include: separating the plurality of inorganic light emitting diodes from a wafer; and transferring the plurality of inorganic light emitting diodes separated from the wafer to the substrate.

[0012] A shorter side of each of the plurality of inorganic light emitting diodes may have a size of 100 μm or less.

[0013] The viscoelastic material may include at least one of a vinyl polymer, an acetate polymer, an ethylene vinyl acetate polymer, an olefin polymer, or an acrylic polymer.

[0014] Upon heating the viscoelastic material to a predetermined temperature, the viscoelasticity of the viscoelastic material may be reduced, and the viscoelastic material may acquire fluidity.

[0015] Forming the encapsulation layer may include: forming the viscoelastic material in a film or a sheet; and laminating the film or the sheet on the substrate.

[0016] Forming the encapsulation layer may include laminating the viscoelastic material on the substrate while applying heat and pressure under a vacuum state. Forming the encapsulation layer may include placing a compensation layer on the encapsulation layer to planarize the encapsulation layer.

[0017] The method may further include removing the compensation layer after the encapsulation layer is cured.

[0018] The substrate may include: a glass substrate; and a thin film transistor (TFT) layer formed on the glass substrate and configured to drive the plurality of inorganic light emitting diodes.

[0019] Assembling the plurality of unit modules may include arranging the plurality of unit modules in a matrix.

[0020] According to another aspect of the present disclosure, a display device includes a plurality of unit modules; and a cover configured to support the plurality of unit modules. Each of the plurality of unit modules may include: a substrate; a plurality of inorganic light emitting diodes disposed on a mounting surface of the substrate; and an encapsulation layer formed on the mounting surface of the substrate to cover the plurality of inorganic light emitting diodes and the mounting surface of the substrate. The encapsulation layer may include a viscoelastic material having viscoelasticity that varies based on a temperature applied to the viscoelastic material.

[0021] Upon heating the viscoelastic material to a predetermined temperature, the viscoelasticity of the viscoelastic material may be reduced, and the viscoelastic material may acquire fluidity.

[0022] The viscoelastic material may include at least one of a vinyl polymer, an acetate polymer, an ethylene vinyl acetate polymer, an olefin polymer, or an acrylic polymer.

[0023] The substrate may include: a glass substrate; and a thin film transistor (TFT) layer formed on the glass substrate and configured to drive the plurality of inorganic light emitting diodes.

[0024] A plurality of unit modules may be arranged in a matrix.

[0025] By applying heat to the packaging layers of the plurality of unit modules, seams between the plurality of unit modules adjacent to each other may be visually hidden.

[0026] The display device may further include a compensation layer formed on the encapsulation layer to improve flatness of the encapsulation layer.

[0027] The display device may further include a frame disposed between the plurality of unit modules and the cover and coupled to the plurality of unit modules.

[0028] According to another aspect of the present disclosure, a display device includes a plurality of unit modules; and a cover configured to support the plurality of unit modules. Each of the plurality of unit modules may include: a substrate; at least one inorganic light emitting diode package mounted on a mounting surface of the substrate, the at least one inorganic light emitting diode package including: an inorganic light emitting diode; and a molding resin configured to respectively surround the inorganic light emitting diodes; and an encapsulation layer formed on the mounting surface of the substrate to cover the at least one inorganic light emitting diode package and the mounting surface of the substrate. The encapsulation layer may include a viscoelastic material having viscoelasticity that changes based on a temperature applied to the viscoelastic material.

[0029] According to another aspect of the present disclosure, a display device includes a first unit module, the first unit module includes: a first substrate; a plurality of first inorganic light emitting diodes disposed on a first mounting surface of the first substrate; and a first encapsulation layer formed on the first mounting surface of the first substrate to cover the plurality of first inorganic light emitting diodes and the first mounting surface of the first substrate; a second unit module, the first unit module and the second unit module are adjacent to each other with a gap therebetween, the second unit module includes: a second substrate; a plurality of second inorganic light emitting diodes disposed on a second mounting surface of the second substrate; and a second encapsulation layer formed on the second mounting surface of the second substrate to cover the plurality of second inorganic light emitting diodes and the second mounting surface of the second substrate; and a cover configured to support the first unit module and the second unit module. By changing the viscoelasticity of each of the first encapsulation layer and the second encapsulation layer, a seam between the first unit module and the second unit module is visually hidden.

[0030] Upon heating the viscoelastic material of each of the first and second encapsulation layers to a predetermined temperature, the viscoelasticity of each of the first and second encapsulation layers may be reduced and the viscoelastic material of each of the first and second encapsulation layers may obtain fluidity.

[0031] The viscoelastic material of each of the first encapsulation layer and the second encapsulation layer may include at least one of a vinyl-based polymer, an acetate-based polymer, an ethylene vinyl acetate-based polymer, an olefin-based polymer, or an acrylic-based polymer.

[0032] The display device may further include a compensation layer formed on the first encapsulation layer and the second encapsulation layer to improve planarity of the first encapsulation layer and the second encapsulation layer.

[0033]

Beneficial Effects

[0034] A large number of unit modules can be smoothly assembled, and thus a large screen size that meets consumer demands can be provided.

[0035] Although the packaging process on the inorganic light emitting diode is completed, it is possible to find a defective inorganic light emitting diode and easily replace the defective inorganic light emitting diode, thereby improving the durability and reliability of the display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a perspective view of a display device according to an embodiment;

[0037] Figure 2 is an exploded view of components of a display device according to an embodiment;

[0038] Figure 3is a front view showing a state where a plurality of unit modules are arranged in a matrix (with the packaging layer omitted) according to an embodiment;

[0039] Figure 4 is a front view of a single unit module (with the packaging layer omitted) according to an embodiment;

[0040] Figure 5 is a cross-sectional view of a single unit module according to an embodiment of the present disclosure, the cross-sectional view is taken along Figure 4 The line II in FIG. is intercepted (the encapsulation layer is omitted);

[0041] Figure 6 is a cross-sectional view of a unit module on which an encapsulation layer is formed according to an embodiment;

[0042] Figure 7 is a view of a mounting structure of an inorganic light emitting diode according to an embodiment;

[0043] Figure 8 is a view of a unit module on which a compensation layer is formed to improve flatness of an encapsulation layer after an encapsulation layer is formed according to an embodiment;

[0044] Fig. 9 is a view of a plurality of unit modules adjacent to each other according to an embodiment;

[0045] Fig.10 is a view of a display device in which seams between a plurality of unit modules are visually removed by applying heat to an encapsulation layer according to an embodiment;

[0046] Fig.11 is a view showing an operation of removing a partial region of an encapsulation layer located on an upper surface of a defective inorganic light emitting diode according to an embodiment;

[0047] Fig.12 is a view showing a state in which a partial region of an encapsulation layer located on an upper surface of a defective inorganic light emitting diode is removed according to an embodiment;

[0048] Fig.13 is a view showing a state in which a defective inorganic light emitting diode is replaced with a repaired inorganic light emitting diode according to an embodiment;

[0049] Fig.14 is a flowchart showing a method for manufacturing a display device according to an embodiment;

[0050] Fig.15 is a flowchart showing a method for repairing a display device according to an embodiment; and

[0051] Fig.16 is a cross-sectional view of a unit module of a display device according to another example embodiment. DETAILED DESCRIPTION

[0052] The embodiments described in the present disclosure and the configurations shown in the drawings are merely examples of the present disclosure and may be modified in various ways to replace the embodiments and drawings of the present disclosure at the time of filing the present application.

[0053] The singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The shapes and sizes of elements in the drawings may be exaggerated for clarity.

[0054] In the present disclosure, the terms "including", "having", etc. are used to specify features, numbers, steps, operations, elements, components, or a combination thereof, but do not exclude the existence or addition of one or more of the features, elements, steps, operations, elements, components, or a combination thereof.

[0055] The present disclosure will be described more fully hereinafter with reference to the accompanying drawings.

[0056] Figure 1 is a perspective view of a display device 1 according to an embodiment of the present disclosure. Figure 2 is an exploded view of components of the display device 1 according to an embodiment of the present disclosure.

[0057] refer to Figure 1 and Figure 2 The display device 1 is an output device for displaying information and data in the form of characters, characters, graphics, and images. For example, the display device can be implemented as a television (TV), a personal computer (PC), a mobile device, and a digital sign. The display device can be mounted on the ground by a bracket (not shown), or can be mounted on a wall.

[0058] According to an embodiment, Figure 2 As shown, the display device 1 may include: a plurality of unit modules 30A-30L displaying images; a frame 21 supporting the plurality of unit modules 30A-30L; and a rear cover 10 covering the rear surface of the frame 21. The rear cover 10 may form the rear surface of the display device 1.

[0059] The plurality of unit modules 30A-30L may be arranged in an M×N matrix in the upper, lower, left, and right directions so as to be adjacent to each other. According to an embodiment, twelve (12) unit modules 30A-30L are mounted on the frame 21 in the form of a 4×3 matrix, but the number and type of the plurality of unit module arrangements are not limited thereto. Therefore, the number and type of the plurality of unit module arrangements may be modified based on design intent.

[0060] The plurality of unit modules 30A to 30L may be mounted on the frame 21 by various known methods (eg, using magnetic force of a magnet or a mechanical assembly structure).

[0061] The display device 1 may further include: a control board 25 for driving the plurality of unit modules 30A to 30L; and a power supply device (not shown) for supplying power to the plurality of unit modules 30A to 30L.

[0062] The plurality of unit modules 30A-30L may be planar or curved, and the curvature thereof may be varied according to design intention.

[0063] A protective glass 2 configured to protect and support the plurality of unit modules 30A to 30L may be attached to the front surface of each of the plurality of unit modules 30A to 30L. An optical film (not shown) configured to improve optical performance may be provided between the protective glass 2 and the plurality of unit modules 30A to 30L. For example, a circular polarization film, a linear polarization film, a retardation film, an AG / LR / AR / HC film, and a neutral density (ND) film for improving image quality may be used alone as the optical film, or alternatively, two or more of the above films may be laminated and used as the optical film.

[0064] Figure 3 30A to 30L is a front view showing a state in which a plurality of unit modules 30A to 30L are arranged in a matrix according to an embodiment of the present disclosure. Figure 4 30A is a front view of a unit module 30A among a plurality of unit modules 30A to 30L according to an embodiment of the present disclosure. Figure 5 is a cross-sectional view of a single unit module according to an embodiment of the present disclosure, the cross-sectional view being taken along Figure 4 Intercepted by line II in Figure 3-Figure 5 The encapsulation layer is omitted. Figure 7 is a view showing a mounting structure of an inorganic light emitting diode according to an embodiment of the present disclosure.

[0065] refer to Figures 3 to 5 and Figure 7 Each of the plurality of unit modules 30A to 30L may include a substrate 40 and a plurality of inorganic light emitting diodes 50 mounted on a mounting surface 41 of the substrate 40 .

[0066] The substrate 40 may be formed of a material such as polyimide (PI), FR4, and glass. On a mounting surface 41 of the substrate 40, substrate electrodes 44 and 45 electrically connected to the plurality of inorganic light emitting diodes 50 may be formed.

[0067] The substrate 40 may include a base substrate 42 and a thin film transistor (TFT) layer 43 formed on the base substrate 42 to drive the inorganic light emitting diodes 50 among the plurality of inorganic light emitting diodes 50. The base substrate 42 may include a glass substrate. That is, the substrate 40 may include a chip on glass (COG) type substrate.

[0068] The inorganic light emitting diode 50 may be formed of an inorganic material. Therefore, the inorganic light emitting diode 50 may have increased durability and a longer lifespan compared to an organic light emitting diode (OLED) based on an organic material, and the inorganic light emitting diode 50 may have a power efficiency several times greater than that of the OLED.

[0069] The plurality of inorganic light emitting diodes 50 may include a red inorganic light emitting diode 51, a green inorganic light emitting diode 52, and a blue inorganic light emitting diode 53. Figure 5 As shown, a plurality of inorganic light emitting diodes 50 may be formed by mounting a series of red inorganic light emitting diodes 51, green inorganic light emitting diodes 52, and blue inorganic light emitting diodes 53 as a unit on a substrate 40. The red inorganic light emitting diodes 51, green inorganic light emitting diodes 52, and blue inorganic light emitting diodes 53 may together form a single pixel.

[0070] As shown in the figure, the red inorganic light emitting diode 51, the green inorganic light emitting diode 52 and the blue inorganic light emitting diode 53 may be arranged in a row at predetermined intervals, but may be arranged in a different arrangement.

[0071] A plurality of inorganic light emitting diodes 50 may be picked up from a source wafer and transferred onto a substrate 40. The plurality of inorganic light emitting diodes 50 may be picked up and transferred by an electrostatic method using an electrostatic head, a stamp bonding method using an elastic polymer such as polydimethylsiloxane (PDMS) or silicon (Si) as a head, or laser ablation transfer. The width, length, and height of each of the plurality of inorganic light emitting diodes 50 may have a size of several micrometers to several hundred micrometers, and the size of the shorter side (in a plan view) of the width and length of the micro inorganic light emitting diode may be 100 μm or less.

[0072] The plurality of inorganic light emitting diodes 50 may include a first diode electrode 57a and a second diode electrode 57b, and may be formed in the form of a flip chip, wherein the first diode electrode 57a and the second diode electrode 57b are arranged on a side opposite to a light emitting direction of the plurality of inorganic light emitting diodes 50. That is, the first diode electrode 57a and the second diode electrode 57b may be formed on a bottom surface 56 of the inorganic light emitting diode 50. The first diode electrode 57a and the second diode electrode 57b of each of the plurality of inorganic light emitting diodes 50 may be connected to the substrate electrodes 44 and 45 of the substrate 40 by soldering 46. Alternatively, the first diode electrode 57a and the second diode electrode 57b of the inorganic light emitting diode 50 may be connected to the substrate electrodes 44 and 45 of the substrate 40 by an anisotropic conductive film including fine conductive particles.

[0073] In addition, the inorganic light emitting diode 50 may be a lateral type or a vertical type, and may be connected to the substrate electrodes 44 and 45 through wires.

[0074] Figure 6 is a cross-sectional view of a unit module 30A (of the plurality of unit modules 30A to 30L) on which an encapsulation layer is formed according to an embodiment of the present disclosure.

[0075] refer to Figure 6 and Figure 7 After the plurality of inorganic light emitting diodes 50 are mounted on the substrate 40 , an encapsulation layer 60 may be formed on the substrate 40 to physically protect the plurality of inorganic light emitting diodes 50 without causing optical distortion.

[0076] The related art encapsulation layer is formed of a transparent molding material such as epoxy resin or silicon, or a tackifier or adhesive such as optically clear adhesive (OCA) or optically clear resin (OCR).

[0077] According to an embodiment, Figure 6 As shown, the encapsulation layer 60 includes a viscoelastic material having viscoelasticity and a curing degree that vary according to changes in temperature or pressure, so as to physically sufficiently protect the inorganic light emitting diode 50 and improve image quality.

[0078] The viscoelastic material in the encapsulation layer 60 may include at least one of a vinyl polymer, an acetate polymer, an ethylene vinyl acetate polymer, an olefin polymer, or an acrylic polymer.

[0079] When the viscoelastic material of the encapsulation layer 60 is heated and reaches a predetermined temperature, its viscoelasticity may be reduced, and the viscoelastic material may have fluidity. Applying heat to the viscoelastic material may be performed by using ultraviolet rays or infrared rays. The temperature at which the viscoelastic material has fluidity may be about 80°C to about 120°C, but is not limited thereto. When the temperature of the viscoelastic material exceeds 120°C, the viscoelasticity may increase again, and the viscoelastic material may be cured. In addition to applying heat to the viscoelastic material, the viscoelastic material may also be cured by adding a hardener thereto.

[0080] Viscoelastic materials can have a refractive index between 0.5 and 1.8, and the refractive index can be controlled through the use of polymer particles such as fillers and beads.

[0081] The viscoelastic material may include, for example, a material showing a color such as a pigment or a dye. In particular, the viscoelastic material may include a black material. By adjusting the black color, the transmittance may be controlled, and the brightness and reflectance may be controlled according to the transmittance.

[0082] For example, the viscoelastic material may include black organic materials, black inorganic materials and black metals, such as carbon black, polyolefin pigments, azo pigments, azomethine pigments, diammonium pigments, phthalocyanine pigments, quinone pigments, indigo pigments, thioindigo pigments, dioxin pigments, quinacridone pigments, isoindolinone pigments, metal oxides, metal complexes and aromatic hydrocarbons.

[0083] The encapsulation layer 60 may be formed by laminating a viscoelastic material on the substrate 40 through a lamination process.

[0084] That is, the encapsulation layer 60 may be formed by forming a viscoelastic material into a film or sheet having a uniform thickness and laminating the viscoelastic material on the substrate 40. Heat and pressure may be applied under a vacuum state while the viscoelastic material is adhered to the substrate 40. The lamination process may make the thickness of the encapsulation layer uniform and may prevent bubbles from being generated in the encapsulation layer 60, thereby improving the image quality of the display device.

[0085] The encapsulation layer 60 may be formed to surround the outer surface including the upper surface 54 and the side surface 55 of each of the plurality of inorganic light emitting diodes 50. The encapsulation layer 60 may be formed to cover the entire area of ​​the mounting surface 41 of the substrate 40 so as to cover all the inorganic light emitting diodes 50 mounted on the substrate 40. That is, the encapsulation layer 60 may be formed in the entire area of ​​the mounting surface 41 of the substrate 40 so as to have a size corresponding to the size of the substrate 40. In addition, as will be described later, it is appropriate that the encapsulation layer 60 has a size corresponding to the size of the substrate 40 so that the seams between the plurality of adjacent unit modules are visually and effectively removed.

[0086] Figure 8 is a view of a unit module 30A (of a plurality of unit modules 30A- 30L) on which a compensation layer 70 is formed to improve flatness of the encapsulation layer 60 after the encapsulation layer 60 is formed according to an embodiment of the present disclosure.

[0087] refer to Figure 8 , forming the encapsulation layer 60 may include placing the compensation layer 70 on the encapsulation layer 60 including the viscoelastic material so that the encapsulation layer 60 is formed more flat. That is, after placing the compensation layer 70 on the encapsulation layer 60 including the viscoelastic material, the encapsulation layer 60 and the compensation layer 70 may be stacked on each other, which will make the encapsulation layer 60 flat. The compensation layer 70 may include a film or glass. Therefore, the encapsulation layer 60 may be formed to have a uniform thickness as a whole.

[0088] A release agent may be arranged between the compensation layer 70 and the encapsulation layer 60 , and thus the compensation layer 70 may be removed after the encapsulation layer 60 has been cured.

[0089] When retaining the film or glass, the film may include an optical film used in a display device of the related art, for example, triacetyl cellulose (TAC), polyethylene terephthalate (PET), and cycloolefin polymer (COP). These films can improve polarization, phase, transmission, reflection, and haze. The thickness of the film may be in the range of 3 μm to 500 μm. The thickness of the glass may be in the range of 1 μm to 7000 μm. The thickness of the film and the glass may be selected to adjust the boundaries between the plurality of unit modules 30A to 30L.

[0090] Fig. 9 is a view of a plurality of unit modules 30A to 30L adjacent to each other according to an embodiment of the present disclosure. Fig.10 3 is a view of a display device 1 in which seams between a plurality of unit modules 30A to 30L are visually hidden by applying heat to an encapsulation layer according to an embodiment of the present disclosure. The seams are visually recognized by physical gaps between the plurality of unit modules.

[0091] like Fig. 9 As shown, a fine interval may be formed between the plurality of unit modules 30A to 30L adjacent to each other. For example, a gap may be formed between the adjacent unit modules 30A and 30B. Therefore, the joint may be visually recognized through the gap.

[0092] In order to improve the image quality, it is necessary to visually remove the seam G. According to an embodiment of the present disclosure, after assembling the adjacent unit modules 30A and 30B adjacent to each other, heat may be applied to the encapsulation layer 60 of the adjacent unit modules 30A and 30B, and thus the seam G between the adjacent unit modules 30A and 30B adjacent to each other may be hidden.

[0093] When heat is applied to the surface seam of the adjacent unit modules 30A and 30B, the viscoelasticity of the viscoelastic material contained in the encapsulation layer 60 is reduced and fluidity is obtained, and then it is adhered together while flowing, thereby visually removing the seam G. That is, the seam G can be hidden. After the seam G is visually removed, the viscoelastic material may be further heated or a hardener may be added, thereby curing the encapsulation layer 60 again.

[0094] Fig.14 is a flowchart illustrating a method of manufacturing the display device 1 according to an embodiment of the present disclosure.

[0095] refer to Fig.14 , a method for manufacturing a display device according to an embodiment of the present disclosure will be described below.

[0096] First, a plurality of inorganic light emitting diodes 50 are mounted on the substrate 40 ( S110 ).

[0097] Next, an encapsulation layer 60 including a viscoelastic material is formed on the substrate 40 so as to cover the plurality of inorganic light emitting diodes 50 ( S120 ).

[0098] Next, a plurality of unit modules, each of which includes a substrate 40, a plurality of inorganic light emitting diodes 50, and an encapsulation layer 60, are prepared and assembled to be adjacent to each other (S130).

[0099] By applying heat to surface boundaries of the plurality of unit modules adjacent to each other, seams between the plurality of unit modules adjacent to each other are visually hidden ( S140 ).

[0100] Fig.11 is a view illustrating an operation of removing a partial region 61 of the encapsulation layer 60 located on the upper surface of the defective inorganic light emitting diode 58 according to an embodiment of the present disclosure. Fig.12 is a view showing a state in which a partial region 61 of the encapsulation layer 60 on the upper surface of the defective inorganic light emitting diode 58 is removed according to an embodiment of the present disclosure. Fig.13 is a view showing a state in which a defective inorganic light emitting diode 58 is replaced with a replacement inorganic light emitting diode 59 according to an embodiment of the present disclosure. Fig.15 is a flowchart showing a method of repairing the display device 1 according to an embodiment of the present disclosure.

[0101] In the following, reference will be made to Figures 11 to 13 and Fig.15 Since the encapsulation layer 60 includes a viscoelastic material, the display device 1 according to the embodiment of the present disclosure can easily replace a defective inorganic light emitting diode 58 even after the encapsulation layer 60 is formed on the plurality of inorganic light emitting diodes 50 .

[0102] That is, after performing a lighting test on a plurality of inorganic light emitting diodes 50 ( S210 ), when a defective inorganic light emitting diode 58 that cannot be turned on is detected, a partial region 61 of the encapsulation layer 60 placed on the upper surface of the defective inorganic light emitting diode 58 is removed ( S220 ).

[0103] Removing the partial region 61 of the encapsulation layer 60 may include irradiating a laser beam 91 on the partial region 61 of the encapsulation layer 60. Fig.11 , the laser oscillator 90 may be moved to a region above the partial region 61 of the encapsulation layer 60 to radiate the laser beam 91 .

[0104] When the partial region 61 of the encapsulation layer 60 located above the defective inorganic light emitting diode 58 is removed, the defective inorganic light emitting diode 58 is removed from the substrate 40 and a new replacement inorganic light emitting element 59 is installed in its place (S230).

[0105] Alternatively, a new replacement inorganic light emitting diode 59 may be installed in an adjacent area without removing the defective inorganic light emitting diode 58 .

[0106] Next, heat is applied to the encapsulation layer 60 to remove defects in the encapsulation layer 60 (S240). When heat is applied to the encapsulation layer 60, the viscoelasticity of the viscoelastic material of the encapsulation layer 60 is reduced and fluidity is obtained. Then, the viscoelastic material flows, thereby removing the defects of the encapsulation layer 60. After the defects are removed, the viscoelastic material may be further heated or a hardener may be added, thereby curing the encapsulation layer 60 again.

[0107] Fig.16 is a cross-sectional view of a unit module 30A of a display device 1 according to another embodiment of the present disclosure.

[0108] Reference Fig.16 A unit module 30A of the display device 1 according to another embodiment of the present disclosure is described. The same reference numerals are assigned to the same components as those of the above-described embodiment, and descriptions thereof will be omitted.

[0109] Different from the above-described embodiment, each of the unit modules 30A- 30L may include a substrate 40 and a plurality of inorganic light emitting diode packages 250 mounted on a mounting surface 41 of the substrate 40 .

[0110] That is, according to Figure 5-Figure 7 In the previous embodiment, a plurality of inorganic light emitting diodes 50 are mounted on the substrate 40 without being individually molded. Fig.16 As another example shown, at least one ILLED 254 may be molded separately to form an ILLED package 250 , and then the ILLED package 250 may be mounted on the substrate 40 .

[0111] The inorganic light emitting diode package 250 may include an inorganic light emitting diode 254 and a molded resin 255 configured to individually surround the inorganic light emitting diode 254. The molded resin 255 may be formed of a transparent material. The inorganic light emitting diode package 250 may include a red inorganic light emitting diode package 251, a green inorganic light emitting diode package 252, and a blue inorganic light emitting diode package 253.

[0112] On the substrate 40, the encapsulation layer 60 is formed to physically protect the inorganic light emitting diode package 250 without causing optical distortion. The encapsulation layer 60 may include a viscoelastic material having viscoelasticity, and the curing degree of the encapsulation layer 60 may vary according to the variation of applied temperature or pressure.

[0113] As is apparent from the above description, a plurality of inorganic light emitting diodes mounted on a substrate can be physically and securely protected and optical performance can be improved, thereby enhancing image quality of a display device.

[0114] When encapsulating a plurality of inorganic light emitting diodes, the viscoelastic material is formed in the form of a film or a sheet and laminated on a substrate. Therefore, the encapsulation process can be simplified. The seams between adjacent unit modules of the display device can be visually hidden, and thus the display quality can be improved.

[0115] Therefore, a large number of unit modules can be smoothly assembled, and thus a large screen size that meets consumer demands can be provided.

[0116] Although the packaging process on the inorganic light emitting diode is completed, it is possible to find a defective inorganic light emitting diode and easily replace the defective inorganic light emitting diode, thereby improving the durability and reliability of the display device.

[0117] Although some embodiments of the present disclosure have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the present disclosure as defined in the appended claims and their equivalents.

Claims

1. A display device, include: Multiple unit modules; as well as a cover configured to support the plurality of unit modules, Wherein, each of the plurality of unit modules comprises: substrate; a plurality of inorganic light emitting diodes disposed on a mounting surface of the substrate; and an encapsulation layer formed on the mounting surface of the substrate to cover the plurality of inorganic light emitting diodes and the mounting surface of the substrate, and wherein the encapsulation layer includes a viscoelastic material having a viscoelasticity that changes based on a temperature applied to the viscoelastic material, and There are seams between adjacent unit modules in the plurality of unit modules. By heating the viscoelastic material to a predetermined temperature, the viscoelasticity of the viscoelastic material is reduced and the viscoelastic material acquires fluidity, so as to visually hide the seam between the adjacent unit modules.

2. The display device according to claim 1, in, The viscoelastic material includes at least one of ethylene polymers, acetate polymers, ethylene vinyl acetate polymers, olefin polymers or acrylic polymers.

3. The display device according to claim 1, in, The substrate comprises: glass substrate; and A thin film transistor (TFT) layer is formed on the glass substrate and configured to drive the plurality of inorganic light emitting diodes.

4. The display device according to claim 1, in, The plurality of unit modules are arranged in a matrix. 5 . The display device of claim 1 , further comprising a compensation layer formed on the encapsulation layer to improve flatness of the encapsulation layer. 6 . The display device of claim 1 , further comprising a frame disposed between the plurality of unit modules and the cover and coupled to the plurality of unit modules.

7. The display device according to claim 1, in, The viscoelastic material is formed into a film or a sheet, and the film or the sheet is laminated on the substrate.

8. The display device according to claim 7, in, When heat and pressure are applied under vacuum, the viscoelastic material is laminated onto the substrate.

9. A method for manufacturing a display device include: mounting a plurality of inorganic light emitting diodes on a mounting surface of the substrate; forming an encapsulation layer including a viscoelastic material on the mounting surface of the substrate to cover the plurality of inorganic light emitting diodes and the mounting surface of the substrate; Assembling a plurality of unit modules including a first unit module and a second unit module adjacent to each other, each of the plurality of unit modules including the substrate, the plurality of inorganic light emitting diodes, and the encapsulation layer, the first unit module and the second unit module having a joint disposed therebetween; as well as By heating the viscoelastic material of the first encapsulation layer of the first unit module and the second encapsulation layer of the second unit module to a predetermined temperature, the viscoelasticity of the viscoelastic material is reduced and the viscoelastic material acquires fluidity to visually hide the seam between the first unit module and the second unit module.

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