Display device and manufacturing method therefor

Abstract

The present invention is applicable to the technical field of display devices and relates to a display device using, for example, light-emitting diodes (LED), and a manufacturing method therefor. A display device according to one embodiment of the present disclosure may comprise: a substrate; a plurality of light-emitting elements partitioned on the substrate to form a plurality of unit pixels; black layers positioned between the individual light-emitting elements; an encapsulation layer formed on the substrate to cover the plurality of light-emitting elements; a first scattering layer positioned on the encapsulation layer and including first filler particles; a transparent layer positioned on the first scattering layer; and a second scattering layer positioned on the transparent layer and including second filler particles that are larger than the first filler particles.

Description

Display device and manufacturing method thereof

[0001] The present disclosure is applicable to the technical field related to display devices, and relates to, for example, a display device using an LED (Light Emitting Diode) and a method for manufacturing the same.

[0002] As the information society develops, the demand for display devices is also increasing in various forms, and in response to this, various display devices such as LCD (Liquid Crystal Display Device), PDP (Plasma Display Panel), ELD (Electro luminescent Display), VFD (Vacuum Fluorescent Display), OLED (Organic Light Emitting Diode), and Micro LED (Micro Light Emitting Diode) are being researched and used in recent years.

[0003] Digital Signage is a display device that provides specific information as well as broadcast programs in public places such as airports, hotels, hospitals, and subway stations, and is a communication tool that can induce marketing, advertising, training effects, and customer experience for companies, as well as general TV.

[0004] Digital signage is a medium that displays various contents and commercial advertisements by installing display panels such as LCD (Liquid Crystal Display), PDP (Plasma Display Panel), OLED (Organic Light Emitting Diode), and Micro LED (Light Emitting Diode) in fixed locations indoors or outdoors or on devices such as street furniture. It can be installed not only in homes but also in apartment elevators, subway stations, subways, buses, universities, banks, convenience stores, discount stores, and shopping malls, etc. where the public moves.

[0005] Recently, as digital signage becomes larger and more ultra-large, much research is being conducted to improve the image quality of display panels.

[0006] In particular, an optical layer may be provided to improve the optical properties of the display panel, but distortion phenomena such as sparkling may occur due to scattering materials included in the optical layer to reduce reflectivity.

[0007] Therefore, solutions to these problems are emerging.

[0008] According to one embodiment of the present disclosure, it is an object to provide a display device and a manufacturing method thereof capable of preventing or reducing image quality degradation while having a scattering layer of the display device.

[0009] Meanwhile, according to one embodiment of the present disclosure, it is intended to provide a display device and a manufacturing method thereof capable of preventing or reducing black level degradation while having a scattering layer of the display device.

[0010] A display device according to one embodiment of the present disclosure may include: a substrate; a plurality of light-emitting elements configured to be partitioned on the substrate and forming a plurality of unit pixels; a black layer positioned between the individual light-emitting elements; an encapsulating layer formed on the substrate to cover the plurality of light-emitting elements; a first scattering layer positioned on the encapsulating layer and including first filler particles; a transparent layer positioned on the first scattering layer; and a second scattering layer positioned on the transparent layer and including second filler particles having a larger size than the first filler particles.

[0011] A display device according to one embodiment of the present disclosure may include a wiring substrate including a plurality of light-emitting elements configured to be partitioned on a substrate and constitute a plurality of unit pixels, a black layer positioned between the individual light-emitting elements, and an encapsulation layer formed on the substrate to cover the plurality of light-emitting elements; a scattering layer positioned on the wiring substrate and positioned corresponding to the unit pixels and including first filler particles; a transparent adhesive layer positioned on the scattering layer; and an AG coating layer positioned on the transparent adhesive layer and including second filler particles having a larger size than the first filler particles.

[0012] A method for manufacturing a display device according to one embodiment of the present disclosure may include the steps of: providing a wiring substrate including a substrate, a plurality of light-emitting elements configured to be partitioned on the substrate and forming a plurality of unit pixels, a black layer positioned between the individual light-emitting elements, and an encapsulating layer formed on the substrate to cover the plurality of light-emitting elements; forming a first scattering layer including a first base material having first filler particles dispersed therein on the encapsulating layer; providing an optical layer including a second scattering layer including a second base material having second filler particles dispersed therein, the second filler particles having a size larger than the first filler particles positioned on a first surface of a transparent substrate, and a transparent adhesive layer positioned on the second surface of the transparent substrate; and attaching a transparent adhesive layer of the optical layer on the first scattering layer.

[0013] According to an exemplary embodiment of the present invention, the following effects are achieved.

[0014] First, according to the embodiment of the present disclosure, it is possible to prevent the reflection phenomenon of the display and reduce the unevenness of image quality such as sparkling.

[0015] Meanwhile, the phenomenon of non-uniform light distribution according to the viewing angle of the light-emitting element can be improved by the action of the first scattering layer located close to the pixel.

[0016] Meanwhile, according to one embodiment of the present disclosure, a display device can have a scattering layer while preventing or reducing blackness degradation.

[0017] Fig. 1 is a cross-sectional schematic diagram showing a display device according to a first embodiment of the present disclosure.

[0018] FIG. 2 is a planar schematic diagram showing a display device according to the first embodiment of the present disclosure.

[0019] FIG. 3 is a cross-sectional schematic diagram showing a display device according to a second embodiment of the present disclosure.

[0020] FIG. 4 is a planar schematic diagram showing a display device according to a second embodiment of the present disclosure.

[0021] Fig. 5 is a cross-sectional schematic diagram showing a display device according to the first comparative example.

[0022] Fig. 6 is a planar schematic diagram showing a display device according to the first embodiment of the present disclosure.

[0023] Fig. 7 is a cross-sectional schematic diagram showing a display device according to the second comparative example.

[0024] Figures 8 and 9 are schematic diagrams showing display uniformity according to filler particle size.

[0025] Figures 10 and 11 are graphs showing the effect of reducing image quality unevenness according to an embodiment of the present disclosure.

[0026] Fig. 12 is a graph showing the effect of improving the viewing angle according to an embodiment of the present disclosure.

[0027] Fig. 13 is a graph showing the viewing angle luminance deviation according to an embodiment of the present disclosure.

[0028] Figure 14 is a normalized graph of Figure 13.

[0029] Figures 15 to 19 are cross-sectional schematic diagrams showing a manufacturing method according to embodiments of the present disclosure.

[0030] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components will be given the same reference numbers, and redundant descriptions thereof will be omitted. The suffixes "module" and "part" for components used in the following description are assigned or used interchangeably only for the convenience of writing the specification, and do not in themselves have distinct meanings or roles. In addition, when it is determined that a specific description of a related known technology may obscure the gist of the embodiments disclosed in this specification, the embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components will be given the same reference numbers, and redundant descriptions thereof will be omitted. The suffixes "module" and "part" for components used in the following description are assigned or used interchangeably only for the convenience of writing the specification, and do not in themselves have distinct meanings or roles. Additionally, when describing the embodiments disclosed in this specification, detailed descriptions of related known technologies will be omitted if it is determined that such detailed descriptions may obscure the gist of the embodiments disclosed in this specification. Furthermore, it should be noted that the attached drawings are intended only to facilitate understanding of the embodiments disclosed in this specification, and should not be construed as limiting the technical concepts disclosed in this specification.

[0031] Furthermore, although each drawing is described for convenience of explanation, it is also within the scope of the present invention for a person skilled in the art to implement another embodiment by combining at least two drawings.

[0032] Additionally, when an element such as a layer, region or substrate is referred to as existing "on" another element, it will be understood that this may be directly on the other element, or that there may be intermediate elements in between.

[0033] The display device described in this specification is a concept that includes all display devices that display information as a unit pixel or a set of unit pixels. Therefore, it can be applied not only to finished products but also to components. For example, a panel corresponding to a component of a digital TV is also a display device in this specification. Finished products may include mobile phones, smart phones, laptop computers, digital broadcasting terminals, personal digital assistants (PDAs), portable multimedia players (PMPs), navigation systems, slate PCs, tablet PCs, Ultrabooks, digital TVs, desktop computers, etc.

[0034] However, it will be readily apparent to those skilled in the art that the configuration according to the embodiments described herein may be applied to any device capable of displaying, even if it is a new product type developed in the future.

[0035] In addition, the semiconductor light-emitting device mentioned in the specification includes LED, mini LED, micro LED, etc., and may be used interchangeably.

[0036]

[0037] Fig. 1 is a cross-sectional schematic diagram showing a display device according to a first embodiment of the present disclosure. Fig. 2 is a planar schematic diagram showing a display device according to a first embodiment of the present disclosure.

[0038] As illustrated in FIG. 1, the display device (10) may have an optical layer (100) provided on a wiring board (200) including unit pixels (210).

[0039] The wiring board (200) can implement an image by means of unit pixels (210) arranged on the board (230). An encapsulation layer (240) can be formed on the subpixels (211, 212, 213) forming the unit pixel (210). Although FIG. 1 illustrates one unit pixel (210) including three subpixels (211, 212, 213), the wiring board (200) can include a large number of unit pixels (210).

[0040] Subpixels (211, 212, 213) forming a unit pixel (210) may be formed by light-emitting elements (211, 212, 213). For example, the unit pixel (210) may include a first light-emitting element (211), a second light-emitting element (212), and a third light-emitting element (213). For example, the unit pixel (210) may include a red light-emitting element (211), a green light-emitting element (212), and a blue light-emitting element (213).

[0041] The red light-emitting element (211), the green light-emitting element (212), and the blue light-emitting element (213) forming the unit pixel (210) can be electrically connected to electrode pads (not shown) arranged on the substrate (230). Here, the electrode pads and the wiring electrodes connecting these electrode pads are omitted.

[0042] An optical layer (optical film; 100) may be positioned on the wiring board (200). The optical layer (100) may be composed of an optical film laminate. Hereinafter, the terms optical layer and optical film are used interchangeably in the description. The optical film (100) may be attached to the wiring board (200). The wiring board (200) to which the optical film (100) is attached may be referred to as a display device (10).

[0043] Although not shown separately, a modular display device may be implemented in which multiple display devices (10) are combined to realize a larger display area. For example, the display device (10) may be a single display module forming a modular display device. In this way, multiple display devices (10) may be combined in parallel to form a modular display device. A detailed description thereof will be omitted.

[0044] A black layer (250) may be positioned between light-emitting elements (211, 212, 213) forming individual subpixels. This black layer (250) may improve the blackness of the display device (10). For example, the black layer (250) may cause the display device (10) to have a black color when the display device (10) is not driven. As another example, the black layer (250) may improve the contrast ratio of the display. This black layer (250) may have a pattern so as to occupy a certain area between the light-emitting elements (211, 212, 213).

[0045] A sealing layer (240) may be positioned on the substrate (230) to cover a plurality of light-emitting elements (211, 212, 213). This sealing layer (240) may be positioned on the upper surface of the substrate (230) on which the plurality of light-emitting elements (211, 212, 213) and the black layer (250) are formed, thereby flattening the upper surface of the substrate (230).

[0046] In this way, the sealing layer (240) can be placed on the upper surface of the substrate (230) provided with electrode pads (not shown). The sealing layer (240) can be made of an insulating and flexible material, such as polyimide (PI), PET, PEN, etc., and can be formed integrally with the substrate (230) to form a single substrate. In this way, the substrate (230) provided with electrode pads can form a wiring board (100) in which wiring electrodes (not shown) are connected to the electrode pads.

[0047] As described above, the unit pixels of such a wiring board (200) can be implemented by light-emitting elements. In the embodiment of the present invention, a light-emitting diode (LED) is exemplified as a type of semiconductor light-emitting element that converts current into light.

[0048] The substrate (230) may include glass or polyimide (PI). In order to implement a flexible display, any insulating and flexible material, such as polyethylene naphthalate (PEN) or polyethylene terephthalate (PET), may be used as the substrate (230). In addition, the substrate (230) may be made of either a transparent or opaque material.

[0049] The semiconductor light-emitting elements (211, 212, 213) forming the unit pixels may be micro LEDs having a size of several to several hundred microns. In some cases, the semiconductor light-emitting elements (211, 212, 213) may be mini LEDs having a size several tens of times that of the micro LED. Here, the mini LED may have a different stacking structure from the micro LED in addition to its size. Specifically, the mini LED may further include a growth substrate for growing a semiconductor layer.

[0050] As an example of a semiconductor light-emitting element (211, 212, 213) forming a unit pixel, a micro LED or mini LED may have a form in which red (R), green (G), and blue (B) LEDs emit light independently, as well as a stacked LED form in which a single LED is composed of red (R), green (G), and blue (B) layers.

[0051] A scattering layer (260) including filler particles (262) may be positioned on the sealing layer (240). This scattering layer (hereinafter, first scattering layer; 260) may be provided by dispersing filler particles (262; hereinafter, first filler particles) within a base material (261; hereinafter, first base material).

[0052] The first filler particle (262) may have a function of having optical properties in the display device (10). Here, the optical properties may be properties of refracting or scattering light emitted from the light-emitting element (211, 212, 213).

[0053] Light emitted from the light-emitting elements (211, 212, 213) may be refracted or scattered in the first scattering layer (260) including the first filler particles (262). Light scattered in the first filler particles (262) may be emitted toward the upper optical layer (100).

[0054] An optical layer (100) may be positioned on the first scattering layer (260). This optical layer (100) may include a second scattering layer (120) on the transparent layer (130, 110).

[0055] The second scattering layer (120) may include filler particles (122; hereinafter, referred to as second filler particles) having a larger size than the first filler particles (262). The second scattering layer (120) may include the second filler particles (122) within the base material (121). For example, the second scattering layer (120) may be provided by dispersing the second filler particles (122) within the base material (121). The base material (121) may include a transparent resin material. In this way, the second filler particles (122) may be dispersed in the transparent resin material forming the base material (121) and positioned on the transparent substrate (110).

[0056] Here, the transparent substrate (110) may include a material that is transparent and has insulating properties, such as PET or PEN.

[0057] The transparent substrate (110) may be positioned on the first scattering layer (260) by means of an optically clear adhesive (OCA; 130). For example, the transparent adhesive layer (130) may be positioned between the transparent substrate (110) and the first scattering layer (260) to adhere them to each other.

[0058] As an exemplary embodiment, the second filler particle (122) may have a size approximately 10 times larger than the size of the first filler particle (262). Here, the size may refer to the diameter of the filler particle (122, 262) when the filler particle (122, 262) has a spherical shape. Meanwhile, as an example, the size may refer to the length of the long side when the filler particle (122, 262) has an amorphous shape. In addition, the size here may refer to the average size of the filler particle (122, 262).

[0059] For example, the second scattering layer (120) may be positioned on the outer side of the optical layer (100) and function as an AG (anti-glare) layer. In other words, the second scattering layer (120) may be said to perform a scattering function for external light. This second scattering layer (120) may form a rough surface (123) on the surface of the optical layer (100) to prevent external light from being consistently reflected.

[0060] Meanwhile, the rough surface (123) of the second scattering layer (120) can significantly reduce the rate at which total internal reflection occurs in the optical layer (100). The second filler particles (122) included in the second scattering layer (120) can provide a rough surface (123) to the surface of the optical layer (100). At least a portion of the light emitted from the light-emitting elements (211, 212, 213) can be scattered by the second filler particles (122).

[0061] For example, the size of the second filler particles (122) may be 3 to 6 μm. The second filler particles (122) may include at least one of Zr, Si, Ti, Zn, BaS, and oxides thereof. For example, the second filler particles (122) may be made of at least one of Zr, Si, Ti, Zn, BaS, and oxides thereof. For example, the second filler particles (122) may be formed of ZrO2 or TiO2 (high refractive index material). As another example, the second filler particles (122) may be formed of hollow SiO2 (low refractive index material).

[0062] The first scattering layer (260) may include first filler particles (262) within the base material (261). For example, the first scattering layer (260) may be formed by dispersing first filler particles (262) within the base material (261). The base material (261) may include a transparent resin material. In this way, the first filler particles (262) may be dispersed in the transparent resin material forming the base material (261) and coated onto the sealing layer (240).

[0063] For example, the size of the first filler particle (262) may be 1 μm or less. For example, the size of the first filler particle (262) may be 300 to 800 nm.

[0064] The first filler particle (262) may include at least one of Zr, Si, Ti, Zn, BaS, and oxides thereof. For example, the first filler particle (262) may be made of at least one of Zr, Si, Ti, Zn, BaS, and oxides thereof. For example, when the first filler particle (262) is formed of a high-refractive material, it may be formed of ZrO2 or TiO2. As another example, when the first filler particle (262) is formed of a low-refractive material, it may be formed of hollow SiO2.

[0065] For example, the content of the first filler particles (262) may be greater than 0 and greater than 50 mass% of the first scattering layer (260). As a specific example, the content of the first filler particles (262) may be greater than 0 and greater than 30 mass% of the first scattering layer (260). When the first filler particles (262) are present, they may be effective as a scattering layer, but the content thereof may be controlled. For example, if the content of the first filler particles (262) is greater than this, the light efficiency may decrease. On the other hand, if the content of the first filler particles (262) is greater than this, the formation of the first scattering layer (260) may not be easy.

[0066] As mentioned above, the second filler particle (122) may have a size approximately 10 times larger than the first filler particle (262). For a more specific example, the second filler particle (122) may have a size 3.5 to 20 times larger than the first filler particle (262). As another example, the size ratio of the first filler particle (262) to the second filler particle (122) may be 0.05 to 0.15. As described above, the second filler particle (122) may implement the roughness of the AG layer. Meanwhile, the first filler particle (262) may function to allow light emitted from the light-emitting elements (211, 212, 213) to be evenly scattered over an area larger than the light-emitting elements (211, 212, 213).

[0067] Referring to FIG. 2, the first scattering layer (260) may have an area corresponding to the unit pixel (210). For example, the first scattering layer (260) may have an area (first area; a1) or width corresponding to the first light-emitting element (211), the second light-emitting element (212), and the third light-emitting element (213). More specifically, the first scattering layer (260) may have an area (a1) that covers the entire first light-emitting element (211), the second light-emitting element (212), and the third light-emitting element (213). The first scattering layer (260) may evenly scatter light emitted from the first light-emitting element (211), the second light-emitting element (212), and the third light-emitting element (213) to spread to an area approximately the size of the first area (a1) and be emitted upward.

[0068] The pixel arrangement of display devices (10) is gradually becoming more and more high-definition, and even in displays such as signage, micro LEDs with a side length of several to several tens of micrometers (㎛) are being used as pixels. For example, the size of the light-emitting elements (211, 212, 213) may have a side length of 20 ㎛.

[0069] At this time, when only the second scattering layer (120) that can function as an AG film is provided, the size of the second filler particles (122) included in the second scattering layer (120) is about 3 to 6 ㎛, and the size of the second filler particles (122) may be relatively large considering the size of the light-emitting elements (211, 212, 213) used as a light source. Accordingly, a large deviation may occur in the number and distribution shape of the second filler particles (122) per light-emitting area, which may cause an uneven picture quality phenomenon. For example, a sparkling phenomenon may occur on the display screen.

[0070] However, according to an embodiment of the present disclosure, a scattering layer (first scattering layer; 260) having filler particles (first filler particles; 262) of relatively small size is positioned near the pixel (210), and a second scattering layer (120) including second filler particles (122) is provided on the upper portion of the optical layer (100), thereby preventing the display from being illuminated (reflection phenomenon) and reducing uneven image quality such as sparkling.

[0071] Meanwhile, the phenomenon of non-uniform light distribution according to the viewing angle of the light emitting element (211, 212, 213) can be improved by the action of the first scattering layer (260) located close to the pixel (210).

[0072] The effects of the embodiments of the present disclosure will be described in detail below.

[0073]

[0074] Fig. 3 is a cross-sectional schematic diagram showing a display device according to a second embodiment of the present disclosure. Fig. 4 is a planar schematic diagram showing a display device according to a second embodiment of the present disclosure.

[0075] Referring to FIG. 3, the display device (10) may have an optical layer (100) provided on a wiring board (200) including unit pixels (210).

[0076] The wiring board (200) can implement an image by means of unit pixels (210) arranged on the board (230). An encapsulating layer (240) can be formed on the subpixels (211, 212, 213) forming the unit pixels (210).

[0077] The subpixels (211, 212, 213) forming the unit pixel (210) may be formed by light-emitting elements (211, 212, 213). For example, the unit pixel (210) may include a first light-emitting element (211), a second light-emitting element (212), and a third light-emitting element (213). For example, the unit pixel (210) may include a red light-emitting element (211), a green light-emitting element (212), and a blue light-emitting element (213). Although FIG. 3 illustrates one unit pixel (210) including three subpixels (211, 212, 213), the wiring board (200) may include a large number of unit pixels (210).

[0078] The red light-emitting element (211), the green light-emitting element (212), and the blue light-emitting element (213) forming the unit pixel (210) can be electrically connected to electrode pads (not shown) arranged on the substrate (230). Here, the electrode pads and the wiring electrodes connecting these electrode pads are omitted.

[0079] An optical layer (optical film; 100) may be positioned on the wiring board (200). The optical layer (100) may be composed of an optical film laminate. Hereinafter, the terms optical layer and optical film are used interchangeably in the description. The optical film (100) may be attached to the wiring board (200). The wiring board (200) to which the optical film (100) is attached may be referred to as a display device (10).

[0080] Although not shown separately, a modular display device may be implemented in which multiple display devices (10) are combined to realize a larger display area. For example, the display device (10) may be a single display module forming a modular display device. In this way, multiple display devices (10) may be combined in parallel to form a modular display device. A detailed description thereof will be omitted.

[0081] A black layer (250) may be positioned between light-emitting elements (211, 212, 213) forming individual subpixels. This black layer (250) may improve the blackness of the display device (10). For example, the black layer (250) may cause the display device (10) to have a black color when the display device (10) is not driven. As another example, the black layer (250) may improve the contrast ratio of the display. This black layer (250) may have a pattern so as to occupy a certain area between the light-emitting elements (211, 212, 213).

[0082] A sealing layer (240) may be positioned on the substrate (230) to cover a plurality of light-emitting elements (211, 212, 213). This sealing layer (240) may be positioned on the upper surface of the substrate (230) on which the plurality of light-emitting elements (211, 212, 213) and the black layer (250) are formed, thereby flattening the upper surface of the substrate (230).

[0083] As described above, the general configuration of the wiring board (200) and the optical layer (100) according to the present embodiment may be the same as the first embodiment described above. Hereinafter, redundant descriptions will be omitted and the characteristic configurations of the present embodiment will be described.

[0084] The substrate (230) may include glass or polyimide (PI). In order to implement a flexible display, any insulating and flexible material, such as polyethylene naphthalate (PEN) or polyethylene terephthalate (PET), may be used as the substrate (230). In addition, the substrate (230) may be made of either a transparent or opaque material.

[0085] The semiconductor light emitting elements (211, 212, 213) forming the unit pixels may be micro LEDs having a size of several to several hundred microns.

[0086] A scattering layer (263) including filler particles (262) may be positioned on the sealing layer (240). This scattering layer (hereinafter, first scattering layer; 263) may be provided by dispersing filler particles (262; hereinafter, first filler particles) within a base material (261; hereinafter, first base material).

[0087] The first filler particle (262) may have a function of having optical properties in the display device (10). Here, the optical properties may be properties of refracting or scattering light emitted from the light-emitting element (211, 212, 213).

[0088] Here, the first scattering layer (263) according to the present embodiment may have an area (a2; hereinafter, second area) or width corresponding to an individual light-emitting element.

[0089] An optical layer (100) may be positioned on the first scattering layer (263). This optical layer (100) may include a second scattering layer (120) on the transparent layer (130, 110).

[0090] The second scattering layer (120) may include filler particles (122; hereinafter, referred to as second filler particles) having a larger size than the first filler particles (262). The second scattering layer (120) may include the second filler particles (122) within the base material (121). For example, the second scattering layer (120) may be provided by dispersing the second filler particles (122) within the base material (121). The base material (121) may include a transparent resin material. In this way, the second filler particles (122) may be dispersed in the transparent resin material forming the base material (121) and positioned on the transparent substrate (110).

[0091] The transparent substrate (110) may be positioned on the first scattering layer (263) by means of an optically clear adhesive (OCA; 130). For example, the transparent adhesive layer (130) may be positioned between the transparent substrate (110) and the first scattering layer (263) to adhere them to each other.

[0092] The transparent adhesive layer (130) has elasticity before being cured, so it can cover and flatten the first scattering layer (263) having a pattern.

[0093] As an exemplary embodiment, the second filler particle (122) may have a size approximately 10 times larger than the size of the first filler particle (262). Here, the size may refer to the diameter of the filler particle (122, 262) when the filler particle (122, 262) has a spherical shape. Meanwhile, as an example, the size may refer to the length of the long side when the filler particle (122, 262) has an amorphous shape.

[0094] For example, the second scattering layer (120) may be positioned on the outer side of the optical layer (100) and function as an AG (anti-glare) layer. In other words, the second scattering layer (120) may be said to perform a scattering function for external light. This second scattering layer (120) may form a rough surface (123) on the surface of the optical layer (100) to prevent external light from being consistently reflected.

[0095] For example, the size of the second filler particles (122) may be 3 to 6 μm. The second filler particles (122) may include at least one of Zr, Si, Ti, Zn, BaS, and oxides thereof. For example, the second filler particles (122) may be made of at least one of Zr, Si, Ti, Zn, BaS, and oxides thereof. For example, the second filler particles (122) may be formed of ZrO2 or TiO2 (high refractive index material). As another example, the second filler particles (122) may be formed of hollow SiO2 (low refractive index material).

[0096] The characteristics of the second scattering layer (120) as described above may be the same as those of the first embodiment described above.

[0097] The first scattering layer (263) may include first filler particles (262) within the base material (261). For example, the first scattering layer (263) may be formed by dispersing first filler particles (262) within the base material (261). The base material (261) may include a transparent resin material. In this way, the first filler particles (262) may be dispersed in the transparent resin material forming the base material (261) and coated onto the sealing layer (240).

[0098] For example, the size of the first filler particle (262) may be 1 μm or less. For example, the size of the first filler particle (262) may be 300 to 800 nm.

[0099] The first filler particle (262) may include at least one of Zr, Si, Ti, Zn, BaS, and oxides thereof. For example, the first filler particle (262) may be made of at least one of Zr, Si, Ti, Zn, BaS, and oxides thereof. For example, when the first filler particle (262) is formed of a high-refractive material, it may be formed of ZrO2 or TiO2. As another example, when the first filler particle (262) is formed of a low-refractive material, it may be formed of hollow SiO2.

[0100] For example, the content of the first filler particles (262) may be greater than 0 and greater than 50 mass% of the first scattering layer (263). As a specific example, the content of the first filler particles (262) may be greater than 0 and greater than 30 mass% of the first scattering layer (263). When the first filler particles (262) are present, they may be effective as a scattering layer, but the content thereof may be controlled. For example, if the content of the first filler particles (262) is greater than this, the light efficiency may decrease. On the other hand, if the content of the first filler particles (262) is greater than this, the formation of the first scattering layer (263) may not be easy.

[0101] As mentioned above, the second filler particle (122) may have a size approximately 10 times larger than the first filler particle (262). For a more specific example, the second filler particle (122) may have a size 3.5 to 20 times larger than the first filler particle (262). As another example, the size ratio of the first filler particle (262) to the second filler particle (122) may be 0.05 to 0.15. As described above, the second filler particle (122) may implement the roughness of the AG layer. Meanwhile, the first filler particle (262) may function to allow light emitted from the light-emitting elements (211, 212, 213) to be evenly scattered over an area larger than the light-emitting elements (211, 212, 213).

[0102] As mentioned above, referring to FIG. 4, the first scattering layer (263) may have an area (a2; hereinafter, referred to as the second area) or width corresponding to the individual light-emitting elements. That is, the first scattering layer (263) may have an area (a2) that covers the first light-emitting element (211), the second light-emitting element (212), and the third light-emitting element (213), respectively.

[0103] This first scattering layer (260) can evenly scatter the light emitted from the first light-emitting element (211), the second light-emitting element (212), and the third light-emitting element (213) and spread to the size of the second area (a2) to be emitted upward.

[0104] In this way, the first scattering layer (263) having a pattern corresponding to the first light-emitting element (211), the second light-emitting element (212), and the third light-emitting element (213) can be positioned at a certain interval (first interval; a3) from each other.

[0105] In practice, the area (a2) or width of the first scattering layer (263) may correspond to the area or width between two neighboring black layers (250) positioned on both sides of the corresponding light-emitting element (211, 212, 213). For example, the area (a2) or width of the first scattering layer (263) may be equal to or larger than the area between two neighboring black layers (250) positioned on both sides of the corresponding light-emitting element (211, 212, 213).

[0106] The black layer (250) positioned between two adjacent light-emitting elements can be opened by the gap (a3) ​​between the first scattering layers (263). From a display perspective, the first scattering layer (263) scatters the light emitted from the light-emitting elements (211, 212, 213) while opening the black layer (250), thereby preventing the blackness or contrast ratio of the display from being lowered by the first scattering layer (263).

[0107] According to an embodiment of the present disclosure, a scattering layer (first scattering layer; 263) having relatively small-sized filler particles (first filler particles; 262) is patterned and positioned to correspond to the positions of individual light-emitting elements (211, 212, 213) near a pixel (210), and a second scattering layer (120) including second filler particles (122) is provided on an upper portion of an optical layer (100), thereby preventing the display from being illuminated (reflected) and reducing uneven picture quality such as sparkling. In addition, the reduction in blackness or contrast ratio of the display due to the scattering layer (263) can be minimized.

[0108] Meanwhile, the phenomenon of light distribution unevenness according to the viewing angle of the light emitting elements (211, 212, 213) can be improved by the action of the first scattering layer (263) located close to the pixel (210).

[0109] The effects of the embodiments of the present disclosure will be described in detail below.

[0110]

[0111] Fig. 5 is a cross-sectional schematic diagram showing a display device according to the first comparative example. Fig. 6 is a planar schematic diagram showing a display device according to the first embodiment of the present disclosure. Fig. 7 is a cross-sectional schematic diagram showing a display device according to the second comparative example.

[0112] As described above, the pixel arrangement of the display device (1) is gradually becoming more high-definition, and even in displays such as signage, micro LEDs with a side length of several to several tens of micrometers (㎛) are being used as pixels.

[0113] Fig. 5 shows a first comparative example, in which a light-emitting element (32) and a black layer (34) are arranged on a substrate (31) of a wiring board (30) and an encapsulating layer (33) are included, and an optical layer (20) including an AG film (21) is positioned on the wiring board (30). The AG film (21) is positioned on a transparent substrate (24) and can be attached to the wiring board (30) by a transparent adhesive layer (25).

[0114] At this time, as in the first comparative example illustrated in FIG. 5, when only the AG film (21; or scattering layer) is provided, the size of the filler particles (22) included in the scattering layer (21) is approximately 3 to 6 ㎛, and the size of the filler particles (22) may be relatively large considering the size of the light-emitting element (32) used as a light source (see FIG. 6). Accordingly, a large deviation may occur in the number and distribution shape of the filler particles (22) per light-emitting area, which may cause an uneven picture quality phenomenon. For example, a sparkling phenomenon may occur on the display screen.

[0115] This sparkling phenomenon refers to a phenomenon in which the display screen appears unsmooth due to filler particles (22) of relatively large size.

[0116] Meanwhile, as in the second comparative example illustrated in Fig. 7, when a film (26) is provided that does not include filler particles (22), the display screen may be formed smoothly, but a reflection phenomenon, in which external light is reflected from the display surface, may occur. Accordingly, a mirror-like reflection may occur on the display surface, which may reduce display visibility.

[0117]

[0118] Figures 8 and 9 are schematic diagrams showing display uniformity according to filler particle size.

[0119] Fig. 8 shows a luminance map in the case of having a conical particle structure with a size of 50 μm and an angle of 10° in the display light-emitting surface formed by light-emitting elements (211, 212, 213). In addition, Fig. 9 shows a luminance map in the case of having a conical particle structure with a size of 10 μm and an angle of 10° in the display light-emitting surface formed by light-emitting elements (211, 212, 213).

[0120] For example, the luminescence map of FIG. 8 may correspond to the first comparative example, and the luminescence map of FIG. 9 may correspond to the first or second embodiment of the present disclosure.

[0121] In Fig. 8, the shade on each light-emitting element (32) represents a pattern in which light emitted from each light-emitting element (22) is scattered by filler particles (22).

[0122] Meanwhile, in FIG. 9, the shade on each light-emitting element (211, 212, 213) represents a pattern in which light emitted from each light-emitting element (211, 212, 213) is scattered by filler particles (262).

[0123] In Fig. 9, it can be seen that the pattern of shading is substantially evenly generated on each light-emitting element (211, 212, 213). However, in Fig. 8, it can be seen that the pattern of shading is different from each other on each light-emitting element (32).

[0124] In this way, it can be seen that it is advantageous for the filler particles (262) used as scattering materials in the display to have a relatively small size.

[0125]

[0126] Figures 10 and 11 are graphs showing the effect of reducing image quality unevenness according to an embodiment of the present disclosure.

[0127] Fig. 10 shows the luminance standard deviation (σ) at the frontal angle of the display screen according to the comparative example (first comparative example) and the embodiment of the present disclosure. That is, Fig. 10 shows the luminance standard deviation (σ) when the display is viewed from the front.

[0128] In the embodiment of the present disclosure, ZrO2 is used as the first filler particle (262) in the first scattering layer (260), and the luminance standard deviation (σ) is shown when the content of the first filler particle (262) is 5 wt% (weight ratio) and 30 wt%, respectively.

[0129] In this way, when viewed from the front of the display, it can be seen that sparkling is reduced in accordance with the embodiment of the present disclosure compared to the first comparative example.

[0130] Referring to FIG. 10, when 5 wt% of the first filler particles (262) are used, the standard deviation of luminance may be smaller, but the light scattering effect may be better when 30 wt% of the first filler particles (262) are used.

[0131] Here, data is shown for a case where the size of the first filler particle (262) is 500 nm. Here, the size of the first filler particle (262) may refer to the average particle size. The size of the first filler particle (262) may also be applied equally to the following description.

[0132] Fig. 11 shows the luminance standard deviation (σ) at a side angle of a display screen according to a comparative example (first comparative example) and an embodiment of the present disclosure. That is, Fig. 10 shows the luminance standard deviation (σ) according to a side angle when the display is viewed from the side.

[0133] Here, the data indicated as AGLR 35% represents the results of the first comparative example. Here, the content of the scattering agent is indicated to be 35 wt%.

[0134] In addition, the data indicated as AGLR 35%_ZrO2 5wt% corresponds to the case in which ZrO2 is used as the first filler particle (262) in the first scattering layer (260) in the embodiment of the present disclosure, and the content of the first filler particle (262) is 5wt% (weight ratio). Meanwhile, the data indicated as AGLR 35%_ZrO2 30wt% corresponds to the case in which ZrO2 is used as the first filler particle (262) in the first scattering layer (260) in the embodiment of the present disclosure, and the content of the first filler particle (262) is 30wt% (weight ratio).

[0135] Referring to Figure 11, in the case of the first comparative example, it can be seen that the luminance deviation increases significantly depending on the angle. At this time, it can be seen that the luminance deviation increases rapidly at an angle of approximately 10 degrees.

[0136] On the other hand, according to the embodiment of the present disclosure, it can be confirmed that the luminance deviation does not increase significantly depending on the angle in both cases.

[0137]

[0138] Fig. 12 is a graph showing the effect of improving the viewing angle according to an embodiment of the present disclosure.

[0139] Referring to FIG. 12, in the embodiment of the present disclosure, the viewing angle improvement effect is shown when 5 wt% of ZrO2 is used as the first filler particle (262) in the first scattering layer (260), and when 30 wt% of ZrO2 is used as the first filler particle (262).

[0140] Referring to FIGS. 10 and 11 above, it can be seen that the case where 5 wt% of ZrO2 was used is superior in terms of the standard deviation of luminance, but considering the standard deviation of luminance at a viewing angle of 60°, it can be seen that the effect of improving the viewing angle is better when 30 wt% of ZrO2 was used.

[0141] Fig. 13 is a graph showing the viewing angle luminance deviation according to an embodiment of the present disclosure. Fig. 14 is a normalized graph of Fig. 13.

[0142] Referring to FIG. 13, when considering the standard deviation of luminance by viewing angle (vertical axis) for white light, it can be seen that the embodiment of the present disclosure is superior to the first comparative example (refer) in terms of the standard deviation of luminance by viewing angle.

[0143] According to the results normalized for the case of Fig. 13, it can be confirmed that the luminance standard deviation decreased by 19% points when 5 wt% of ZrO2 was used compared to the first comparative example at a viewing angle of 60°. In addition, it can be confirmed that the luminance standard deviation decreased by 31.5% points more when 30 wt% of ZrO2 was used compared to when 5 wt% of ZrO2 was used.

[0144] As described above, when ZrO2 is used as the first filler particle (262), it can be seen that the standard deviation of luminance decreases as the content increases. Accordingly, it can be seen that the uniformity of image quality improves as the content of the first filler particle (262) increases. Meanwhile, as mentioned above, the content of the first filler particle (262) can be used at 50 wt% or less.

[0145]

[0146] Figures 15 to 19 are cross-sectional schematic diagrams showing a manufacturing method according to embodiments of the present disclosure.

[0147] Hereinafter, with reference to FIGS. 15 to 19, a manufacturing method according to embodiments of the present disclosure will be described step by step.

[0148] The manufacturing method according to the embodiments of the present disclosure may largely include a step of providing a wiring substrate (200), a step of providing an optical layer (100), and a step of bonding the wiring substrate (200) and the optical layer (100) (Fig. 19).

[0149] First, referring to FIGS. 15 and 16, a process may be performed to provide a wiring board (200) including a substrate (230), a plurality of light-emitting elements (211, 212, 213) that are partitioned on the substrate (230) and constitute a plurality of unit pixels (210), a black layer (250) positioned between the individual light-emitting elements (211, 212, 213), and an encapsulating layer (240) formed on the substrate (230) to cover the plurality of light-emitting elements (211, 212, 213).

[0150] For example, referring to FIG. 15, a plurality of light-emitting elements (211, 212, 213) constituting a plurality of unit pixels (210) on a substrate (230) and a black layer (250) positioned between the individual light-emitting elements (211, 212, 213) can be formed.

[0151] Thereafter, referring to FIG. 16, a sealing layer (240) formed on a substrate (230) to cover a plurality of light-emitting elements (211, 212, 213) can be formed.

[0152] Next, referring to FIG. 17, according to the first embodiment, a first scattering layer (260) including a first base material (261) having first filler particles (262) dispersed on a sealing layer (240) can be formed.

[0153] The first scattering layer (260) may have an area (a1) corresponding to a unit pixel (210).

[0154] The first scattering layer (260) may be formed by at least one process among screen printing, slit coating, spin coating, dot printing, and film lamination. Meanwhile, the second scattering layer (120) may also be formed by at least one process among screen printing, slit coating, spin coating, dot printing, and film lamination.

[0155] Meanwhile, referring to FIG. 18, according to the second embodiment, a first scattering layer (263) including a first base material (261) having first filler particles (262) dispersed on a sealing layer (240) can be formed.

[0156] The first scattering layer (263) may have an area (a2) corresponding to the unit light-emitting elements (211, 212, 213). For example, the first scattering layer (263) may have an area (a2) that locally covers the individual light-emitting elements (211, 212, 213). That is, the first scattering layers (263) may be provided to be divided from each other with a first gap (a3).

[0157] Referring to FIG. 19, an optical layer (100) can be prepared that includes a second scattering layer (120) including a second base material (121) in which second filler particles (122) larger in size than first filler particles (262) are dispersed on one side of a transparent substrate (110), and a transparent adhesive layer (130) on the other side of the transparent substrate (110).

[0158] The process of providing a wiring board (200) and the process of providing an optical layer (100) can be performed independently of each other.

[0159] An optical layer (100) can be bonded onto the wiring board (200) such that the transparent adhesive layer (130) faces the wiring board (200). In this way, when the wiring board (200) and the optical layer (100) are bonded, a display device (10) according to the second embodiment described with reference to FIGS. 3 and 4 can be manufactured. Meanwhile, the optical layer (100) can be bonded to the wiring board (200) as shown in FIG. 17, so that a display device (10) according to the first embodiment can be manufactured.

[0160]

[0161] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by those skilled in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be construed as falling within the scope of the present invention.

[0162] In addition, although the above description focuses on examples, these are merely examples and do not limit the present invention. Those skilled in the art to which the present invention pertains will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present invention. For example, each component specifically shown in the examples can be modified and implemented. In addition, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention defined in the appended claims.

[0163] According to the present invention, a display device using an LED (Light Emitting Diode) and a manufacturing method thereof can be provided.

Claims

1. Substrate; A plurality of light-emitting elements formed on the substrate and constituting a plurality of unit pixels; A black layer positioned between the individual light-emitting elements; An encapsulating layer formed on the substrate to cover the plurality of light-emitting elements; A first scattering layer positioned on the above encapsulating layer and including first filler particles; A transparent layer positioned on the first scattering layer; A second scattering layer comprising second filler particles positioned on the transparent layer and having a larger size than the first filler particles. Display device.

2. In the first paragraph, the second scattering layer is located on a transparent substrate. Display device.

3. In the first paragraph, the transparent substrate is bonded to the sealing layer by a transparent adhesive layer. Display device.

4. In the first paragraph, the size ratio of the first filler particle and the second filler particle is 0.05 to 0.

15. Display device.

5. In the first paragraph, the first filler particle includes at least one of Zr, Si, Ti, Zn, BaS, and oxides thereof. Display device.

6. In the first paragraph, the content of the first filler particles is greater than 0 and less than or equal to 50 mass% of the first scattering layer. Display device.

7. In the first paragraph, the size of the first filler particle is 300 to 800 nm. Display device.

8. In the first paragraph, the first scattering layer has an area corresponding to the unit pixel. Display device.

9. In the first paragraph, the first scattering layer has an area corresponding to the individual light-emitting element. Display device.

10. In paragraph 9, each first scattering layer is positioned with a first interval. Display device.

11. In the 10th paragraph, the first gap defines the width of the black layer opening. Display device.

12. A step of providing a wiring board including a substrate, a plurality of light-emitting elements that are partitioned on the substrate and constitute a plurality of unit pixels, a black layer positioned between the individual light-emitting elements, and a sealing layer formed on the substrate to cover the plurality of light-emitting elements; A step of forming a first scattering layer including a first base material having first filler particles dispersed on the above-mentioned sealing layer; A step of providing an optical layer comprising a second scattering layer including a second base material in which second filler particles larger in size than the first filler particles are dispersed on a first surface of a transparent substrate, and a transparent adhesive layer positioned on the second surface of the transparent substrate; and A step of attaching a transparent adhesive layer of the optical layer on the first scattering layer. A method for manufacturing a display device.

13. In the 12th paragraph, the step of providing the wiring board and the step of providing the optical layer are performed independently. A method for manufacturing a display device.

14. In the 12th paragraph, the step of forming the first scattering layer is performed so as to have an area that locally covers the individual light-emitting elements. A method for manufacturing a display device.

15. In the 12th paragraph, the step of forming the first scattering layer is performed so as to have an area corresponding to the unit pixel. A method for manufacturing a display device.

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