LED panel using semiconductor light emitting element, manufacturing method thereof, and display device including LED panel

Abstract

The LED panel includes: a base substrate including a circuit wiring; a plurality of light emitting diodes disposed to form an array on the base substrate; a side optical layer laterally positioned to the plurality of light emitting diodes and including a diffusant; and a plurality of upper optical layers on top of the plurality of light emitting diodes, respectively, and including a diffusant, the LED panel may provide uniform light in all directions through uniform light distribution by reducing chromatic aberration of different viewing angles occurring due to the structure of the semiconductor light emitting diodes.

Description

Technical Field

[0001] The present disclosure relates to a display device using a semiconductor light emitting element. In particular, the present disclosure relates to a display device that uniformly improves light distribution of an RGB chip and increases brightness through the structure of a semiconductor light emitting element. Background Art

[0002] As the information society continues to develop, the demand for display devices has also grown in various forms. In response to this trend, various display devices such as liquid crystal displays (LCDs), field emission displays (FEDs), plasma display panels (PDPs), electroluminescent devices, etc. have been developed recently.

[0003] The liquid crystal panel of the LCD may include a liquid crystal layer, and may further include a thin film transistor (TFT) substrate and a color filter substrate arranged to face each other with the liquid crystal panel interposed therebetween, and may display an image using light provided from a backlight unit.

[0004] A light emitting diode (LED) is a semiconductor light emitting device known for converting electric current into light, and has been used as a light source for displaying images in electronic devices including information and communication devices together with a GaP:N-based green LED since red LEDs using GaAsP compound semiconductors were commercialized in 1962. Semiconductor light emitting elements have various advantages over filament-based light emitting elements such as long life, low power consumption, excellent initial driving characteristics, and high vibration resistance.

[0005] Here, the semiconductor light emitting element may include at least one of a mini LED and a micro LED. Although there is no precise size definition, a micro LED may be an LED having a size of several micrometers to tens of micrometers, and a mini LED may be an LED having a size several tens times that of a micro LED.

[0006] A display device using a semiconductor light emitting element can be thinned and implemented in various shapes. For example, the light emitting element can enable a curved display device or a flexible display device to be implemented.

[0007] LEDs can be used for outdoor displays because of their high brightness, which makes them highly visible outdoors. Specifically, unit panels composed of light-emitting elements can be arranged in a tiled manner to achieve a large screen.

[0008] However, in the case of a large screen, the angle at which the user views the screen varies depending on the position on the screen. The viewing angle of light varies depending on the color, and therefore the color of the image perceived by the user at one side of the screen is different from the color of the image perceived when the user is in front of the screen. Summary of the invention

[0009] Technical issues

[0010] An object of one embodiment is to provide a display device using a semiconductor light emitting element.

[0011] Another object of one embodiment is to provide a display device using a semiconductor light emitting element that can reflect light emitted from the side of an LED chip mounted on a substrate back into the element to improve the efficiency of the LED chip, increase brightness and reduce power consumption.

[0012] Another object of one embodiment is to provide a display device that minimizes light distribution by reducing color differences between viewing angles caused by the structure of a semiconductor light emitting diode.

[0013] Another object of one embodiment is to provide a display device that improves light extraction efficiency in a forward direction by achieving uniform light distribution of RGB chips, thereby minimizing bright lines caused by an assembly step between modules.

[0014] Technical Solution

[0015] In one aspect of the present disclosure, a light emitting diode (LED) panel may include: a base substrate including circuit wiring; a plurality of LEDs arranged in an array on the base substrate; a side optical layer positioned on a lateral side of the plurality of LEDs, the side optical layer containing a diffuser; and a plurality of upper optical layers, each upper optical layer being positioned on a top surface of the plurality of LEDs and containing a diffuser.

[0016] The upper optical layer may have a size corresponding to that of the top surface of the LED.

[0017] The upper optical layer may have an aspect ratio of 0.6 or less.

[0018] A top surface of the upper optical layer may include a curved surface.

[0019] The upper optical layer may include silicone, wherein a refractive index difference between the diffuser and the silicone may be greater than or equal to 0.3.

[0020] The diffusing agent may include a silicone diffusing agent including at least one of SiO2, ZrO2, ZnO, or TiO2.

[0021] The side optical layer may have a height corresponding to the height of the LEDs and fill gaps between the LEDs.

[0022] The side optical layer may include silicone, wherein the refractive index difference between the diffuser and the silicone may be greater than or equal to 0.3.

[0023] The side optical layers can reflect or absorb light emitted from the lateral sides of the LED.

[0024] The LED panel may further include a black layer positioned on a top surface of the side optical layer.

[0025] The black layer may contain carbon or a UV absorbing material.

[0026] The black layer may be formed by carbonizing the side optical layer (which may include a layer of carbon-containing silicone or epoxy) with a laser.

[0027] The LED panel may further include a transparent resin layer covering the side optical layer and the upper optical layer and positioned on top surfaces of the side optical layer and the upper optical layer.

[0028] The transparent resin layer may contain scattering particles.

[0029] The LED panel may further include at least one of an anti-reflection (AR) (or anti-glare (AG)) film, a low reflection (LR) film, or an anti-fingerprint (AF) film laminated on the transparent resin layer.

[0030] The LED may be a stacked LED each having a red light emitting chip, a blue light emitting chip, and a green light emitting chip sequentially stacked on the base substrate.

[0031] The LED may include a parallel type LED having a red light emitting chip, a blue light emitting chip, and a green light emitting chip arranged side by side.

[0032] In another aspect of the present disclosure, a method for manufacturing a light emitting diode (LED) panel may include the following steps: providing a base substrate having circuit wiring; mounting a plurality of LEDs in an array on the base substrate; forming an upper optical layer on a top surface of each of the plurality of LEDs; forming a side optical layer positioned on a lateral side of the plurality of LEDs; and forming a black layer by carbonizing the top surface of the side optical layer by radiating laser light onto the side optical layer.

[0033] In another aspect of the present disclosure, a display device may include: a display module having a plurality of light emitting diode (LED) panels arranged in an array; a frame allowing the plurality of LED panels to be mounted in the frame; and a controller connected to the display module to control the display module, wherein each LED panel may include: a base substrate including circuit wiring; a plurality of LEDs arranged in an array on the base substrate; a side optical layer positioned on a lateral side of the plurality of LEDs, the side optical layer containing a diffuser; and an upper optical layer positioned on a top surface of each of the LEDs and containing a diffuser.

[0034] Beneficial Effects

[0035] According to one embodiment of the present disclosure, a display device using a semiconductor light emitting element can reflect light emitted from the side of an LED chip mounted on a substrate back into the element, thereby improving the efficiency of the LED chip, increasing brightness and reducing power consumption.

[0036] By reducing the color difference between viewing angles caused by the structure of the semiconductor light emitting diode, uniform white light can be obtained in all directions through uniform light distribution.

[0037] Effects that can be obtained from the present embodiment are not limited to the above-mentioned effects, and other unmentioned effects can be clearly understood from the above description by a person of ordinary skill in the technical field to which the present disclosure pertains. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a block diagram illustrating components of a display device according to the present disclosure.

[0039] Figure 2 is a perspective view illustrating an example of a display device according to the present disclosure.

[0040] Figure 3 is an exploded perspective view of a display panel according to the present disclosure.

[0041] Figure 4 is a diagram illustrating an example of a single light emitting diode.

[0042] Figure 5 is a schematic diagram illustrating the direction in which light is emitted from a light emitting diode.

[0043] Figure 6 This is a diagram illustrating light distribution of a light emitting diode.

[0044] Figure 7 is a cross-sectional view illustrating one embodiment of an LED panel according to one aspect of the present disclosure.

[0045] Figure 8 is an example Figure 7 A diagram of the beam angle of a specific color of LED.

[0046] Fig. 9 is a diagram illustrating another embodiment of an LED panel according to an aspect of the present disclosure.

[0047] Fig.10 is a diagram illustrating another embodiment of an LED panel according to an aspect of the present disclosure.

[0048] Fig.11 is a diagram illustrating the shape of the numerical aperture (NA) output by color depending on the presence / absence of the upper optical layer.

[0049] Fig.12is a diagram illustrating a beam angle of a specific color of light emitted from a light emitting diode including an upper optical layer having a diffusing agent added thereto.

[0050] Fig.13 The color viewing angles of the LED panel according to one aspect of the present disclosure and the conventional LED panel are illustrated. DETAILED DESCRIPTION

[0051] Now, the exemplary embodiments disclosed herein will be described in detail with reference to the accompanying drawings. In order to be briefly described with reference to the accompanying drawings, the same reference numerals may be provided for the same or equivalent components, and no further description is given herein. Generally, suffixes such as "module" and "unit" may be used to refer to elements or components. Such suffixes are used herein only for the convenience of describing the specification, and the suffixes themselves are not intended to give any special meaning or function. In the present disclosure, for the sake of brevity, the contents known to those of ordinary skill in the relevant art have generally been omitted. The accompanying drawings are used to help easily understand various technical features, and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. Therefore, the present disclosure should be interpreted as extending to any changes, equivalents and substitutes other than those specifically listed in the accompanying drawings.

[0052] It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally used only to distinguish one element from another.

[0053] It will be understood that when an element is referred to as being “connected” to another element, the element may be directly connected to the other element, or intervening elements may also be present. Conversely, when an element is referred to as being “directly connected” to another element, there are no intervening elements.

[0054] Unless the context indicates a clearly different meaning, a singular expression may include a plural expression.

[0055] Terms such as "including" or "having" are used herein, and it should be understood that these terms are intended to indicate the presence of several components, functions, or steps disclosed in the specification, and it should also be understood that more or fewer components, functions, or steps may also be utilized.

[0056] Figure 1 is a block diagram illustrating a display device 100 related to the present disclosure.

[0057] Display device 100 may include wireless communicator 110 , input unit 120 , sensing unit 140 , output unit 150 , cooling portion 160 , memory 170 , controller 180 , and power supply 190 . Figure 1The components shown in are not necessary to implement the display device 100, and the display device 100 described herein may have more or fewer components than those listed above.

[0058] More specifically, the wireless communicator 110 among the components may include one or more modules that enable wireless communication between the display device 100 and a wireless communication system, between the display device 100 and another display device 100, or between the display device 100 and an external server. In addition, the wireless communicator 110 may include one or more modules that connect the display device 100 to one or more networks.

[0059] The wireless communicator 110 may include at least one of a mobile communication module, a wireless Internet module, or a short-range communication module.

[0060] The input unit 120 may include a camera 121 or an image input unit configured to input an image signal, a microphone 122 or an audio input unit configured to input an audio signal, and a user input unit 123 (e.g., a touch key, a mechanical key, etc.) configured to input information from a user. Voice data or image data collected by the input unit 120 may be analyzed and processed as a control command from the user.

[0061] Recently, as the size of the frame of the display device 100 is reduced, the number of display devices 100 each including the minimum number of input units 130 exposed to the outside in the form of physical buttons is rapidly increasing. On the contrary, the minimum number of physical buttons may be provided on the back or side surface of the display device 100. The display device may receive a user input through a touch panel or a user input interface unit described later through a remote controller.

[0062] The sensing unit 140 may include one or more sensors configured to sense at least one of information in the display device 100, information about the environment around the display device 100, or user information. For example, the sensing unit 140 may include at least one of a proximity sensor, an illumination sensor, a touch sensor, an RGB sensor, an infrared (IR) sensor, a finger scan sensor, an ultrasonic sensor, an optical sensor (e.g., camera 121), a microphone (see 122), a battery gauge, an environmental sensor (e.g., a barometer, a hygrometer, a thermometer, a radiation detection sensor, a heat detection sensor, a gas detection sensor, etc.), a chemical sensor (e.g., an electronic nose, a healthcare sensor, or a biometric sensor, etc.). The display device 100 disclosed herein may use a plurality of pieces of information sensed by at least two of these sensors in combination.

[0063] The controller 180 may check the state of the display apparatus 100 based on the information collected by the sensing unit 140 , may notify a user of a problem, or may control the display apparatus 100 to be maintained in an optimal state.

[0064] The output unit 150 is configured to generate output related to vision, hearing or touch, and may include at least one of a display unit 151 and a sound output unit 152. The display unit 151 may be layered or integrally formed with a touch sensor, thereby implementing a touch screen. Such a touch screen may be used as a user input unit 123 to provide an input interface between the display device 100 and the user, and may provide an output interface between the display device 100 and the user.

[0065] The display unit 151 may be implemented as a plasma display panel (PDP), a liquid crystal display (LCD), an organic light emitting diode (OLED), a flexible display, etc. In addition, the display unit 151 may also be implemented as a three-dimensional (3D) display. The three-dimensional (3D) display may be classified into a non-glasses type 3D display and a glasses type 3D display.

[0066] Furthermore, the display unit 151 may be constructed of a touch screen, whereby an input device may be used in addition to an output device.

[0067] Reference Figure 2 , the display device 100 according to the present disclosure may implement a large-screen display 151 by arranging a plurality of display modules 200 in a grid shape.

[0068] The cooling part 160 refers to a component that dissipates heat from the display device 100 , and may include a heat pipe or cooling fins, a circulation fan configured to enhance air circulation within the display device 100 , an exhaust hole, and the like.

[0069] When installed for exhibition or advertising purposes, the display device 100 is operated for a long time and outputs high brightness that is clearly visible from the outside. Therefore, the heat generated by the display unit 151 and the controller 180 may affect each component of the display device 100, causing malfunctions, etc. Therefore, a heat dissipation structure that dissipates internal heat is very important.

[0070] In the display device 100, heat dissipation is achieved in various ways. Depending on how heat transfer is performed during the heat dissipation process, heat dissipation can be divided into air cooling or water cooling. In the case of air cooling, the heat dissipation efficiency can be increased by maximizing the surface area using heat dissipation fins, etc. In the case of water cooling, the heat dissipation efficiency can be improved by using a structure such as a heat pipe to guide the flow and sealing of a heat transfer material.

[0071] Any one of these cooling methods for heat dissipation may be used alone, or two or more of these methods may be used in combination as needed.

[0072] The memory 170 stores data that supports various functions of the display device 100. The memory 170 may store instructions, a plurality of application programs or applications running on the display device 100, and data for operating the display device 100. At least some of these applications may be downloaded from an external server via wireless communication. In addition, at least some of these applications may be pre-installed on the display device 100 at the factory for basic functions of the display device 100 (e.g., making and receiving calls, receiving messages, and sending messages). The application may be stored in the memory 170, installed on the display device 100, and driven by the controller 180 to perform the operation (or function) of the display device 100.

[0073] In addition to application-related operations, the controller 180 generally controls the overall operation of the display device 100. The controller 180 may provide or process appropriate information or functions for the user by processing signals, data, information, etc. input or output through the above components or by driving applications stored in the memory 170.

[0074] Furthermore, the controller 180 may control at least some of the components to execute the application stored in the memory 170. Furthermore, the controller 180 may operate at least two of the components included in the display apparatus 100 in combination to drive the application.

[0075] The controller 180 may include at least one processor, and the processor included therein may be used to control the overall operation of the display device 100. Here, the processor may be a general-purpose processor such as a central processing unit (CPU). Of course, the processor may be a dedicated device such as an ASIC or other hardware-based processor.

[0076] The image signal processed by the controller 180 may be input to the display module 151 which may display an image corresponding to the image signal.

[0077] In addition, the image signal processed by the controller 180 may be input to an external output device through the external device interface unit 112 .

[0078] In addition, the controller 180 may control the display device 100 according to a user command input through a user input interface unit or an internal program. In addition, the controller 180 may control the display module 151 to display an image. At this time, the image displayed on the display module 151 may be a still image or a video, or may be a 2D image or a 3D image.

[0079] In addition, the controller 180 may perform control so that a predetermined 2D object is displayed in the image displayed on the display module 151. For example, the object may be at least one of a connected web page (newspaper or magazine), an electronic program guide (EPG), various menus, widgets, icons, still images, videos, and texts.

[0080] In addition, the controller 180 may modulate and / or demodulate the signal using an amplitude shift keying (ASK) method. Here, the amplitude shift keying (ASK) method may be a method of changing the amplitude of a carrier according to a data value to modulate a signal or restoring an analog signal to a digital data value according to the amplitude of a carrier.

[0081] For example, the controller 180 may modulate the image signal using an amplitude shift keying (ASK) method, and may transmit the modulated image signal through the wireless communication module.

[0082] For example, the controller 180 may demodulate and process the image signal received through the wireless communication module using an amplitude shift keying (ASK) method.

[0083] As a result, the display device 100 can easily transmit and receive signals to and from another image display device disposed adjacent thereto without using a unique identifier such as a media access control (MAC) address or a complex communication protocol such as TCP / IP.

[0084] The power supply 190 may supply power to the components of the display device 100. Specifically, the power supply may supply power to the controller 180 which may be implemented in the form of a system on chip (SOC), the display unit 151 for image display, and the sound output unit 152 for audio output.

[0085] Specifically, the power supply 190 may include an AC / DC converter (not shown) configured to convert AC power into DC power and a DC / DC converter (not shown) configured to convert a level of the DC power.

[0086] The power supply 190 is used to distribute power supplied from the outside to each component of the display device. The power supply 190 may be directly connected to an external power source to supply AC power, or may include a battery to be used by charging.

[0087] At least some components may operate in cooperation with each other to implement the operation, control or control method of the display device 100 according to various embodiments described below. In addition, the operation, control or control method of the display device 100 may be implemented on the display device 100 by driving at least one application stored in the memory 170.

[0088] That is, two or more elements may be integrated into one element, or one element may be divided into two or more elements as required. In addition, the functions performed by each block are used to describe the embodiments of the present disclosure, and the specific operations and components thereof do not limit the scope of rights of the present disclosure.

[0089] Figure 2 1 is a perspective view illustrating an example of a display device 100 according to the present disclosure. The display device may have a rectangular body including a pair of long sides and a pair of short sides.

[0090] The display device 100 may be implemented in which an image is output to a display such as Figure 2 The display unit 151 of the display module 200 is formed integrally as shown in (a), and a plurality of display modules 200 may be formed as shown in Figure 2 (b) is arranged in a grid shape (in a tiled manner) to form a large screen.

[0091] Since each display module 200 uses a thin substrate or sheet, the display module 200 may be bent or damaged. The display module 200 may include a cover bottom 102. The cover bottom 102 may support a rear surface of a display to form a rear exterior of the display device 100.

[0092] Reference Figure 2 (a), the display device 100 using one display module 200 may use a cover bottom 102 corresponding to the size of the display module 200. Figure 2 In the case of the plurality of display modules 200 shown in (b), the plurality of display modules 200 may be mounted to one cover bottom 102 in a grid shape.

[0093] The cover bottom 102 may use a metal material such as iron, aluminum, and magnesium for rigidity and heat generation. In order to effectively dissipate the heat generated from the display module 200, a heat sink 102a may be further provided on the front surface of the cover body 102. The heat sink 102a may include a material having a high thermal conductivity, and may improve the heat dissipation effect by rapidly spreading the heat in the surface direction while transferring the heat to the cover bottom 102.

[0094] In order to pass Figure 2 In order to realize a display device 100 having a large screen by arranging a plurality of display modules 200 as shown in (b), it is necessary to arrange the display modules 200 so that the gaps therebetween are as narrow as possible. Even when the display modules 200 are closely arranged, due to the characteristics of light, the light emitted from the backlight will make the gaps between the display modules 200 visible when emitted from the sides of the display modules 200.

[0095] The display device 100 in a tiled form may need to block light projected in a lateral direction to ensure that the boundaries between the display modules 200 are not visible.

[0096] Furthermore, when the display device 100 of a large screen is implemented in a tiled manner, the user's viewing angle varies depending on the position of the display module 200. In this case, if the viewing angle differs depending on the type of light, the user may perceive different colors depending on the position on the screen.

[0097] In addition, regarding viewing angles, when the display device 100 is installed outdoors, the user may view the display device 100 from the front, side, top, or bottom. Therefore, a display module 200 that provides a user with an image of uniform color at various viewing angles including a front view is required.

[0098] Figure 3 is an exploded perspective view of the display module 200 according to the present disclosure. Figure 3 , the display module 200 may further include a plurality of unit panels 220. The LED panel may include a plurality of LEDs 222 arranged in an array, and a controller configured to control the LEDs 222 may be provided on a rear surface of the panel.

[0099] The LED panel 220 may be implemented by a semiconductor light emitting element. In the present disclosure, a light emitting diode (LED) 222 is exemplified as a semiconductor light emitting element that converts current into light.

[0100] Each LED 222 serves as a pixel for realizing an image. The size of each LED 222 can be realized as 1 mm or less, and the pitch between the LEDs 222 (ie, the pitch between pixels) can be realized as 3 mm or less.

[0101] The LED 222 includes a light emitting chip 2224 that generates light, and further includes an encapsulation layer 2224 disposed thereon to protect the light emitting chip 2223. The encapsulation layer 2224 serves to uniformly diffuse light emitted from the light emitting chip 2223.

[0102] As for the LED 222, when a micro LED having a smaller size than the LED 222 used as a light source in the past is adopted, the LED panel 220 may become thinner and more bendable due to the smaller size of the light source.

[0103] Figure 4 2 is a diagram illustrating an example of a single LED 222. Figure 4 In (a), the LED 222 is a single chip including only light emitting chips 2223 differentiated by color (ie, one color). Each chip of the LED 222R, 222G, 222B of a specific color may be connected to an electrode 2212 on the base substrate 221.

[0104] In the figure, the top side is the front side of the LED panel 220 from which light is emitted, facing the front of the display device 100. Hereinafter, since the LED panel 220 faces upward when it is manufactured, it will be described as a top surface or a top side.

[0105] Three colors of red (R), green (G), and blue (B) constitute one pixel. The three colors may be alternately arranged on the base substrate 221, or an LED 222 having three colors in one package may be used.

[0106] In the figure, (b) shows that a stacked LED 222 of a single pixel can be realized by stacking light-emitting chips 2223R, 2223G and 2223B of three colors. This configuration can result in a greater thickness than the lateral arrangement of the LEDs, which can reduce the size of the LEDs 222, thereby allowing a denser arrangement of the LEDs 222. Therefore, an LED panel 220 with finer pixels can be realized. In addition, since the colors are at different horizontal positions, the color difference according to the position can be reduced during light synthesis.

[0107] For simplicity, the following description is based on Figure 4 The stacked LED 222 having the light emitting chip 2223 arranged vertically as shown in (b) of FIG. 1 is shown in FIG. 2 , but the embodiment is not necessarily limited thereto. Figure 4 The LED module shown in (a) has light emitting chips 2223 arranged in a horizontal direction.

[0108] LED 222 can be Figure 3 The LEDs 2222 are shown arranged in an array on a base substrate 221 comprising an insulating material. Although the LEDs 2222 are shown as being larger in size, they may actually be hundreds of microns in size and spaced more closely together than conventional light sources.

[0109] The base substrate 221 includes an insulating material (e.g., polyimide (PI)), although polyethylene naphthalate (PEN) and polyethylene terephthalate (PET) are also available. The base substrate 221 includes electrodes 2212 connected to each LED 222. The LED 222 can be turned on / off and supplied with power via the electrodes.

[0110] As a light source, the packaged LED 222 is packaged to protect R, G, and B color chips and synthesize R, G, and B color lights to form white light, thereby forming an encapsulation layer 2224 .

[0111] The light emitting chips of LED 222 may each include a p-type electrode, a p-type semiconductor layer on which the p-type electrode is formed, an active layer formed on the p-type semiconductor layer, an n-type semiconductor layer formed on the active layer, and an n-type electrode on the n-type semiconductor layer horizontally spaced apart from the p-type electrode.

[0112] Figure 5 2 is a schematic diagram illustrating a direction in which light is emitted from LED 222. Light may be emitted in a vertical direction from the top surface of the LED element, and the viewing angle of the light exceeds 100°. Therefore, light emitted from LED 222 may be seen from a direction tilted at an angle to the vertical direction. Light projected in a lateral direction as described above may weaken the intensity of light supplied in the forward direction, resulting in a reduction in brightness.

[0113] Furthermore, due to different viewing angles for colors and different positions of light emitting elements for colors, light emitted from the LED 222 may have different light distributions.

[0114] Figure 6 2 is a diagram illustrating the light distribution of LED 222, wherein (a) illustrates the light distribution of green, (b) illustrates the light distribution of blue, and (c) illustrates the light distribution of red. For blue and red, the light emitted forward has the strongest intensity. On the other hand, for green, the light is widely diffused in the lateral direction.

[0115] The beam angle is an angle indicating the range of light emission based on light distribution, which means the angle range in which light is distributed in the vertical direction. The beam angle of green light with wide diffuse light distribution may be 72°, while the beam angle of red or blue light may be 66° to 67°.

[0116] Therefore, when the LED panel 220 is viewed from a side direction at an angle to the front, the LED panel 220 may appear light green rather than completely white due to the large amount of green light emitted. On the other hand, red is strong in the forward direction, and thus red light may be emitted. Therefore, it is necessary to configure the LED panel 220 to have a uniform color distribution.

[0117] By guiding the light that spreads laterally to emit light forward, the green color widely emitted in the lateral direction is emitted forward. When the beam angle of green is reduced, green has a beam angle similar to other colors, and thus the light distribution and beam angle of each color can be adjusted to be similar.

[0118] Figure 7 is a cross-sectional view illustrating one embodiment of an LED panel 220 according to one aspect of the present disclosure.

[0119] According to this disclosure, Figure 7As shown, a side optical layer 223 surrounding the lateral surface of the LED 222 may be added to guide the light emitted in the lateral direction forward. The side optical layer 223 is located at the lateral side of the LED 222, and may reflect the light emitted from the lateral side of the LED 222 to guide the light forward. The side optical layer 223 is in close contact with the lateral side of the LED 222, and may be formed by applying and curing a silicone epoxy resin on a base substrate 221 having the LEDs 222 arranged in an array thereon. In this case, the side optical layer 223 may be formed to have a height corresponding to the height of the LED 222 or a height smaller than the height of the LED 222.

[0120] The side optical layer 223 may be applied by a spraying method using a printer outputting epoxy resin, a molding method, or the like, and may be formed to cover the lateral sides except for the top surface of the LED 222 .

[0121] The side optical layer 223 may be formed by applying a resin (epoxy resin) containing silicone and a diffusing agent to fill the space between the LEDs 222. The lateral sides of the side optical layer 223 are in close contact with the LEDs 222.

[0122] The top surface of the layer can be Figure 7 (a) is flat, or Figure 7 The shape of the top surface may vary depending on the manufacturing method and density of the silicone epoxy resin forming the side optical layer 223 .

[0123] Figure 7 (a) illustrates a molding method for forming a relatively flat top surface, and Figure 7 (b) illustrates a spraying method, which provides a lower viscosity than a molding method and thus makes the layer taller around the wall portion in contact with the LED 222 due to surface tension.

[0124] The diffusing agent included in the side optical layer 223 may include a material having a large refractive index such as TiO2, SiO2, ZrO2, or ZnO. The diffusing agent may have a refractive index difference of 0.3 or more with silicone as a main material, and diffuse scattering may occur due to the refractive index difference between the diffusing agent and the main material.

[0125] When the side optical layer 223 contains a bright colored diffuser such as TiO2, the reflective effect can be further achieved due to the bright color. Figure 7 As shown in (a), light emitted in a lateral direction of the LED 222 may be reflected back to the encapsulation layer 2224, thereby increasing the amount of light emitted in a forward direction.

[0126] By reflecting light emitted from the lateral sides of the LED 222 and projecting it forward, the amount of light emitted forward can be increased (resulting in improved light efficiency), and the brightness can be improved.

[0127] [Table 1]

[0128] color Side Optical LayerX Side optical layer O Green (G) 0.729 0.835(15％↑) Red (R) 0.813 0.88(8％↑) Blue (B) 0.82 0.87(6％↑)

[0129] Table 1 shows the light efficiency of colors depending on the presence / absence of the side optical layer 223. In the presence of the side optical layer 223, the light efficiency of all colors can be improved, resulting in an overall increase in light efficiency of more than 10%.

[0130] In particular, in the case of green, the brightness is significantly improved due to the high forward reflection ratio of the light widely diffused in the lateral direction. In addition, the intensity or brightness of the light emitted in the forward direction is similar between colors, and thus the synthesized light can have a uniform white color.

[0131] A black layer 224 may also be provided on the top surface of the side optical layer 223. The black layer 224 may be a resin layer containing a dark material such as carbon, and thus may absorb light. In the case where the side optical layer 223 is exposed to the front side, external light may be reflected by the side optical layer 223, thereby reducing the visibility of the image output from the display device 100.

[0132] The black layer 224 can absorb external light and prevent visibility from being deteriorated by the external light, and can thus improve the visibility of the display device 100 even outdoors. In addition, when the display device 100 is in an inactive state (ie, a power-off state), it can increase the black contrast of the front surface of the display device 100.

[0133] However, since the black layer 224 already absorbs light, if the layer overlaps with the LED 222 or has a large area, it may block the light emitted by the LED 222 from passing forward.

[0134] Therefore, the black layer 224 may be formed on the top surface of the side optical layer 223 such that it is positioned on the lateral side of the LED 222 to minimize the area overlapping the front of the LED 222. The black layer 224 may be implemented by carbonizing silicone in the side optical layer 223 by laser irradiating the side optical layer 223. In other words, the side optical layer 223 may be irradiated with laser.

[0135] The side optical layer 223 may contain carbon or a UV absorbing material and may change color in response to a specific wavelength of laser light.

[0136] In the case of using dark silicone to realize the side optical layer 223, the separate black layer 224 can be omitted. Since the reflectivity of the dark side optical layer 223 is less than the reflectivity of the light side optical layer 223, the effect of the layer recycling light emitted in the lateral direction is reduced, but the process of manufacturing the black layer 224 can be omitted, which has the advantage of minimizing the area where the black layer 224 overlaps with the LED 222.

[0137] Figure 8 is an example Figure 7 Graph of the beam angles for specific colors of LEDs 222. A side optical layer 223 may be used to narrow the beam angle toward the front to 60.5° for green, 57.5° for red, and 57° for blue.

[0138] Since the side optical layer 223 positioned on the lateral side reflects light forward, the beam angle can be narrower than the beam angle in the embodiment without the side optical layer 223. It can be seen that the difference between the maximum and minimum values ​​of the beam angle is about 6° in the absence of the side optical layer 223, but by adding the side optical layer 223, the difference is reduced to about 3.5°.

[0139] [Table 2]

[0140] color Side Optical LayerX Side optical layer O Green (G) 72° 60.5° Red (R) 66° 57.5° Blue (B) 66.5° 57° Δ Angle 6° 3.5°

[0141] However, the beam angle of green is still larger than that of red and blue, and thus the angle needs to be further compensated to reduce chromatic aberration.

[0142] In the case of stacking the light source, the light emitting chips are stacked at the bottom in the order of red, blue, and green, and thus the green light emitting chip 2223G is disposed closest to the top surface of the encapsulation layer 2224 of the LED 222 .

[0143] The beam angle tends to be inversely proportional to the distance f from the emission surface to each light emitting chip 2223. Therefore, green, which has the shortest distance, has the largest beam angle. An upper optical layer 227 may be added to further reduce the beam angle of green.

[0144] Fig. 9 is a diagram illustrating another embodiment of an LED panel 220 according to an aspect of the present disclosure.

[0145] The figure illustrates an LED panel 220 further including an upper optical layer 227 of LED 222. The upper optical layer 227 can be positioned on the top surface of the LED 222, such as Fig. 9 As shown. The upper optical layer 227 may refract the light emitted from the LED 222 to adjust the beam angle. By refracting the green light having a large beam angle, the beam angle may be reduced by about 3°, that is, reduced to about 57.5°.

[0146] The upper optical layer 227 may be formed on the LED 222 by a spraying process. The upper optical layer 227 may include transparent silicone and a diffuser 2275. The diffuser may include a material having a large refractive index such as SiO2, ZrO2, or ZnO.

[0147] The diffusing agent may have a refractive index difference of 0.3 or more with silicone as a main material, and diffuse scattering may occur due to the refractive index difference between the diffusing agent and the main material.

[0148] Unlike the above-mentioned diffusing agent, a colorless material may be used for the diffusing agent in consideration of light transmittance, or a smaller amount of the diffusing agent than the diffusing agent may be added.

[0149] The side optical layer 223 does not need to have high viscosity because the side optical layer 223 is injected between the plurality of LEDs 222, and a side wall may be provided along the periphery of the LED panel to prevent overflow of silicone (epoxy resin) used to form the side optical layer 223. On the other hand, the upper optical layer 227 may adopt silicone (epoxy resin) having a higher viscosity than the side optical layer 223 so as to be located on the top surface of the LED 222 without spreading too widely, and thus a curved surface may be formed on the top surface.

[0150] The size of the upper optical layer 227 may be configured such that the aspect ratio is about 0.6 or less. As the viscosity increases, the surface of the upper optical layer 227 may become more convex.

[0151] The upper optical layer 227 may be formed as Fig. 9 The side optical layer 223 shown is formed later, but may be extended wider in the lateral direction. In this case, a gap may be formed between the black layer 224 and the LED 222.

[0152] Fig.10 2 is a diagram illustrating another embodiment of an LED panel 220 according to an aspect of the present disclosure. In this embodiment, an upper optical layer 227 is positioned on the LED 222 so that the size of the LED 222 is equal to the size of the upper optical layer 227.

[0153] The upper optical layer 227 may be formed first, and then the side optical layer 223 and the black layer 224 may be formed so that the upper optical layer 227 is positioned on the LED 222. After the upper optical layer 227 is formed, the side optical layer 223 may be formed, and the black layer 224 may be implemented by laser irradiation on the top surface of the side optical layer 223. In this case, the gap between the LED 222 and the black layer 224 may be eliminated, thereby allowing more precise control of light emitted from the LED 222.

[0154] A laser responsive diffuser (e.g., TiO2) is not included in the upper optical layer 227, so that when laser is radiated to form the black layer 224, only the side optical layer 223 reacts and the color of the upper optical layer 227 does not change. In order to protect the black layer 224 and the upper optical layer 227, a transparent resin layer 225 may be formed to cover the black layer 224 (or if the black layer 224 is omitted, the side optical layer 223) and the upper optical layer 227. The transparent resin layer 225 may include a silicone or epoxy resin material. The transparent resin may protect the LED 222 and the applied black layer 224, and may be configured so that the front surface of the display device 100 is flat.

[0155] The functional film layer 226 may also be disposed on the front surface of the transparent resin layer 225 to prevent light reflection of external light. The functional film layer 226 may include at least one of an anti-reflection (AR) (or anti-glare (AG)) film, a low reflection (LR) film, or an anti-fingerprint (AF) film.

[0156] In addition, when the LED panel is in a power-off state, the functional film layer 226 including a color with a transmittance greater than or equal to at least 30% can allow individual pixels (individual light-emitting elements) to be almost invisible, thereby achieving a black screen effect.

[0157] Fig.11 are diagrams illustrating the shape of the numerical aperture (NA) output by color depending on the presence / absence of the upper optical layer 227 , wherein (a) illustrates an embodiment without the upper optical layer 227 , and (b) illustrates an embodiment with the upper optical layer 227 .

[0158] Referring to (a), it can be seen that the light intensity from the point light source in the central light source portion is strong, and the green light has a maximum NA shape.

[0159] Referring to (b) illustrating the NA of an embodiment including the upper optical layer 227 , the NAs of the colors are similar in size and have a uniform square shape.

[0160] Fig.12 2 is a diagram illustrating a beam angle of a specific color of light emitted from an LED 222 including an upper optical layer 227 to which a diffusing agent is added. The beam angle is reduced and has a uniform shape rather than a shape that is greatly diffused in the lateral direction. In addition, since the color difference is small, uniform white light can be obtained.

[0161] Fig.13The color viewing angles of an LED panel according to one aspect of the present disclosure and a conventional LED panel are illustrated. The horizontal axis represents the viewing angle and the vertical axis represents the color difference. A wider viewing angle has the effect of making certain colors more visible. Conventional LED panels show that the color difference increases as the viewing angle increases. According to the present disclosure, similar color difference can be obtained even when the viewing angle increases.

[0162] As the content of the diffusing agent in the upper optical layer increases, the effect of reducing the chromatic aberration according to the viewing angle can be enhanced. However, as the amount of the diffusing agent increases, the brightness may decrease. The appropriate amount of the diffusing agent is about 10% to 20%.

[0163] As described above, one embodiment of the present disclosure can provide a display device 100 using such a semiconductor light emitting element, which can reflect light emitted from the lateral surface of an LED chip mounted on a substrate back into the element to improve the efficiency of the LED chip while increasing brightness and reducing power consumption.

[0164] By reducing the color difference of the viewing angle caused by the structure of the semiconductor LED 222, uniform white light can be obtained in all directions through uniform light distribution.

[0165] The above description is merely an example of the technical concept of the present disclosure. It is obvious to those skilled in the art that various modifications and changes can be made in the present disclosure without departing from the spirit and scope of the present disclosure.

[0166] Therefore, the embodiments disclosed herein are intended to illustrate rather than limit the technical concept of the present disclosure, and the scope of the technical concept of the present disclosure is not limited by these embodiments.

[0167] The above detailed description should not be interpreted as limiting in any aspect, and should be considered as exemplary. The scope of the present disclosure should be determined by the reasonable interpretation of the attached claims. Therefore, the present disclosure is intended to cover the modification and variation of the present disclosure, as long as they fall within the scope of the attached claims and their equivalents.

Claims

1. A light emitting diode (LED) panel, comprising: a base substrate, the base substrate including circuit wiring; a plurality of LEDs, the plurality of LEDs being arranged in an array on the base substrate; a side optical layer positioned on a lateral side of the plurality of LEDs, the side optical layer comprising a diffusing agent; as well as A plurality of upper optical layers, each of the plurality of upper optical layers being positioned on a top surface of the plurality of LEDs and comprising a diffuser.

2. The LED panel according to claim 1, wherein: The upper optical layer has a size corresponding to a size of the top surface of the LED.

3. The LED panel according to claim 1, wherein: The upper optical layer has an aspect ratio of 0.6 or less.

4. The LED panel according to claim 1, wherein: A top surface of the upper optical layer includes a curved surface.

5. The LED panel according to claim 1, wherein: The upper optical layer comprises silicone, Wherein, the refractive index difference between the diffusing agent and the silicone is greater than or equal to 0.

3.

6. The LED panel according to claim 5, wherein: The diffusing agent includes a silicone diffusing agent including at least one of SiO2, ZrO2, or ZnO.

7. The LED panel according to claim 1, wherein: The side optical layer has a height corresponding to a height of the LEDs and fills gaps between the LEDs.

8. The LED panel according to claim 1, wherein: The side optical layer comprises silicone, Wherein, the refractive index difference between the diffusing agent and the silicone is greater than or equal to 0.

3.

9. The LED panel according to claim 1, wherein: The side optical layers reflect or absorb light emitted from lateral sides of the LED.

10. The LED panel according to claim 1, further comprising: A black layer is positioned on a top surface of the side optical layer.

11. The LED panel according to claim 10, wherein: The black layer contains carbon or an ultraviolet absorbing material.

12. The LED panel according to claim 10, wherein: The black layer is formed by carbonizing the side optical layer with a laser.

13. The LED panel according to claim 1, further comprising: A transparent resin layer covers the side optical layer and the upper optical layer and is positioned on top surfaces of the side optical layer and the upper optical layer.

14. The LED panel according to claim 13, wherein: The transparent resin layer contains scattering particles.

15. The LED panel according to claim 13, further comprising: At least one of an anti-reflection AR or anti-glare AG film, a low-reflection LR film, or an anti-fingerprint AF film laminated over the transparent resin layer.

16. The LED panel according to claim 1, wherein: The LEDs are stacked LEDs each having a red light emitting chip, a blue light emitting chip, and a green light emitting chip stacked in sequence on the base substrate.

17. The LED panel according to claim 1, wherein: The LED includes a parallel type LED having a red light emitting chip, a blue light emitting chip, and a green light emitting chip arranged side by side.

18. A method for manufacturing the light emitting diode (LED) panel according to claim 1, the method comprising the following steps: providing a base substrate having circuit wiring; mounting a plurality of LEDs in an array on the base substrate; forming an upper optical layer on a top surface of each of the plurality of LEDs; forming a side optical layer positioned on lateral sides of the plurality of LEDs; as well as The black layer is formed by carbonizing a top surface of the side optical layer by irradiating laser onto the side optical layer.

19. A display device, comprising: A display module, wherein the display module has a plurality of light emitting diode (LED) panels arranged in an array; a frame, the frame allowing the plurality of LED panels to be mounted therein; as well as a controller connected to the display module to control the display module, Wherein, each of the LED panels comprises: a base substrate, the base substrate including circuit wiring; a plurality of LEDs, the plurality of LEDs being arranged in an array on the base substrate; a side optical layer positioned on a lateral side of the plurality of LEDs, the side optical layer comprising a diffusing agent; and An upper optical layer is positioned on a top surface of each of the LEDs and includes a diffuser.

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