Display device using semiconductor light-emitting element

Abstract

A backlight unit according to an embodiment includes: a base substrate including a circuit wiring; the plurality of light emitting diodes are arranged on the basic substrate to form an array; a diffusion layer laterally around each of the light emitting diodes; and correction lenses on top of the corresponding light emitting diodes, and can provide uniform white light in all directions through uniform light distribution by reducing chromatic aberration of different viewing angles 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 the light distribution of an RGB chip and increases the brightness by utilizing the structure of the semiconductor light emitting element. Background Art

[0002] As the information society continues to develop, the demand for display devices in various forms is also increasing. 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] Display devices using semiconductor light emitting elements can be thinned and implemented in various shapes. For example, the light emitting elements can implement curved display devices or flexible display devices.

[0007] Semiconductor light emitting elements can be used as backlights for LCD panels or as display pixels for RGB displays. Considering the pixel size, micro LEDs, which are smaller in size than mini LEDs, are used for displays, while mini LEDs are used for backlights.

[0008] Mini LEDs are smaller in size and thickness than LEDs used for regular backlights, and can therefore be arranged more densely, thereby reducing the thickness of the backlight. Compared with regular LEDs, they can improve contrast and also reduce power consumption.

[0009] To use mini LED as backlight, RGB colors must be synthesized to output white light. In order for the synthesized light to become white light, the light distribution of each color must be uniform. Summary of the invention

[0010] Technical issues

[0011] An object of one embodiment is to provide a display device using a semiconductor light emitting element.

[0012] 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.

[0013] Another object of one embodiment is to provide a display device that minimizes light distribution by reducing a color difference between viewing angles caused by a structure of a semiconductor light emitting diode.

[0014] 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.

[0015] Technical Solution

[0016] In one aspect of the present disclosure, a backlight unit includes: a base substrate including circuit wiring; a plurality of light emitting diodes arranged in an array on the base substrate; a diffusion layer positioned around lateral surfaces of the light emitting diodes; and a correction lens positioned on a top surface of the light emitting diodes.

[0017] The correction lens may be greater than or equal to the diagonal length of the light emitting diode.

[0018] The correction lenses may each include a silicone diffuser including at least one of TiO2, SiO2, or ZrO2.

[0019] The correction lens may have a height to diameter ratio less than or equal to 0.3.

[0020] The correction lens may include a square anamorphic lens.

[0021] The light emitting diode may include a light emitting diode including red, blue, and green light emitting chips.

[0022] The light emitting diode may include a stacked light emitting diode having red, blue, and green colors stacked on a base substrate.

[0023] The diffusion layer may include a silicone diffuser including at least one of TiO 2 , SiO 2 , or ZrO 2 , wherein the diffusion layer may reflect and diffuse light emitted from a lateral side of the light emitting diode.

[0024] The diffusion layer may have a white color.

[0025] The diffusion layer may include a black dye layer positioned on a top surface of the diffusion layer and on a side surface of the correction lens.

[0026] The black dye layer may contain carbon or an ultraviolet absorbing material.

[0027] The black dye layer may be arranged not to overlap with a top surface of the light emitting diode.

[0028] The backlight unit may further include a transparent resin layer covering the black dye layer and the light emitting diodes.

[0029] The backlight unit 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 over the transparent resin layer.

[0030] In another aspect of the present disclosure, a display device includes: a display panel; a backlight unit configured to provide light to the display panel, wherein the backlight unit may include: a base substrate including circuit wiring; a plurality of light emitting diodes arranged in an array on the base substrate; a diffusion layer positioned around a lateral surface of the light emitting diode; and a correction lens positioned on a top surface of the light emitting diode.

[0031] The correction lens is greater than or equal to the diagonal length of the light emitting diode.

[0032] The correction lenses each include a silicone diffuser including at least one of TiO2, SiO2, or ZrO2.

[0033] The correction lens may have a height to diameter ratio less than or equal to 0.3.

[0034] The correction lens may include a square anamorphic lens.

[0035] The light emitting diode may include a light emitting diode including red, blue, and green light emitting chips, wherein the light emitting diode may include a stacked light emitting diode having red, blue, and green colors stacked on a base substrate.

[0036] Beneficial Effects

[0037] 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.

[0038] 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.

[0039] 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

[0040] Figure 1 is a block diagram illustrating components of a display device according to the present disclosure.

[0041] Figure 2 is a perspective view illustrating an example of a display device according to the present disclosure.

[0042] Figure 3 is an exploded perspective view of a display panel according to the present disclosure.

[0043] Figure 4 is a diagram illustrating an example of a single light emitting diode.

[0044] Figure 5 is a schematic diagram illustrating the direction of light emitted from a light emitting diode.

[0045] Figure 6 This is a diagram illustrating light distribution of a light emitting diode.

[0046] Figure 7 is a cross-sectional view illustrating one embodiment of a backlight unit according to one aspect of the present disclosure.

[0047] Figure 8 is an example Figure 7 A diagram of the beam angle of a specific color of LED.

[0048] Fig. 9 is a diagram illustrating another embodiment of a backlight unit according to an aspect of the present disclosure.

[0049] Fig.10 : is a diagram illustrating the shape of the numerical aperture (NA) output by color according to the presence / absence of the correction lens.

[0050] Fig.11 is a diagram illustrating specific color beam angles of light emitted from a light emitting diode including a correction lens having a diffuser added thereto. DETAILED DESCRIPTION

[0051] Now will be described in detail with reference to the accompanying drawings according to the exemplary embodiments disclosed herein. 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 their description will not be repeated. Generally, suffixes such as "module" and "unit" may be used to refer to elements or components. The use of such suffixes herein is only intended to facilitate the description of 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. In contrast, 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 they 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 portion 140 , output unit 150 , cooling portion 160 , memory 170 , controller 180 , and power supply 190 . Figure 1 The 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 through 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. In contrast, 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 portion 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 portion 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 part 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 visual, auditory or tactile sensations, 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 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 151 may also be implemented as a three-dimensional (3D) display. The three-dimensional (3D) display 151 may be classified into a non-glasses type 3D display and a glasses type 3D display.

[0066] Furthermore, the display 151 may be constituted by 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, and 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 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 a heat sink or the like. 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 from 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 device 100 in combination to drive the application.

[0075] The controller 180 may include at least one processor, and may use the processor included therein 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) screen, 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 module 151 for image display, and the audio 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 provided from the outside to each component of the display device. The power supply 190 may be directly connected to an external power source in order to provide 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 for describing 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 is a perspective view illustrating an example of a display device 100 according to the present disclosure.

[0090] The display device 100 may be implemented in which an image is output to a display such as Figure 2 The display module 200 is integrally formed 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 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 bottom 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 the 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 when the light is emitted from the sides of the display modules 200 makes the gaps between the display modules 200 visible.

[0095] Figure 3 is an exploded view of a display module 200 according to the present disclosure. Figure 3, the display module 200 may employ a liquid crystal display divided into a display panel 210 located on a front side to output an image and a backlight unit 220 located on a rear side thereof.

[0096] The backlight unit 220 may be implemented by a semiconductor light emitting element. In the present disclosure, a light emitting diode (LED) 222 is shown as a type of a semiconductor light emitting element that converts current into light.

[0097] The LED 222 includes a light emitting chip that generates light, and further includes an encapsulation layer 2224 disposed thereon to protect the light emitting chip. The encapsulation layer 2224 serves to uniformly diffuse light emitted from the light emitting chip 2223.

[0098] With regard to the LED 222, as mini LEDs having a smaller size than the LED 222 used as a light source in the past are adopted, the backlight unit 220 can be thinner and more flexible due to the smaller size of the light source.

[0099] 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 LED 222R, 222G, 222B chip of a specific color may be connected to an electrode 2212 on the base substrate 221.

[0100] In the figure, the top side is the front side of the backlight unit 220 from which light is emitted, facing the front of the display device 100. Hereinafter, when the backlight unit 220 is manufactured, it will be described as a top surface or a top side because it faces upward.

[0101] 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.

[0102] In the figure, (b) shows a stacked LED 222 that can realize a single pixel by stacking three colors of light-emitting chips 2223. This configuration may result in a greater thickness than the lateral arrangement of LEDs, but it can reduce the size of a single pixel, thereby allowing a denser arrangement of LEDs. Therefore, a display module 200 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.

[0103] For simplicity, Figure 4As shown in (b), the following description is based on the stacked LEDs 222 with the light emitting chips 2223 arranged vertically, but the embodiment is not necessarily limited thereto. An LED module with the light emitting chips 2223 arranged horizontally may also be used.

[0104] like Figure 3 As shown, LEDs 222 may be disposed on a base substrate 221 configured in an array and including an insulating material. Although LEDs 2222 are shown as being large in size, they may actually be hundreds of microns in size and spaced more closely from each other than conventional light sources.

[0105] 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 connected to each LED 222. The LED 222 can be turned on / off and supplied with power via the electrodes.

[0106] Although not in Figure 3 , but a structure such as a film or a reflector for light diffusion may be added between the front display panel 210 and the backlight unit 220, and a guide panel may also be included to guide the multi-layer structure. As a light source, the packaged LED 222 is packaged to protect the R, G, and B color chips and synthesize the R, G, and B color lights to generate white light, thereby forming an encapsulation layer 2224.

[0107] The LED 222 may include an element controller configured to control each of the R, G, and B color chips. The element controller may increase the response speed of the LED 222.

[0108] 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 horizontally spaced apart from the p-type electrode on the n-type semiconductor layer.

[0109] Figure 5 2 is a schematic diagram illustrating the direction of light emitted from LED 222. Light can be emitted in all directions from the top surface of the LED element and can also be emitted in the lateral direction. The light emitted in this way not only causes the problem of low brightness, but also causes the problem of different colors depending on the direction.

[0110] The light emitted from the LED 222 may have different light distributions due to different wavelengths of the colors and different positions of the light emitting elements of the respective colors.

[0111] Figure 62 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.

[0112] The beam angle is an angle indicating a range of light emission based on light distribution. The beam angle of green having a wide spread light distribution may be 72°, while the beam angle of red or blue may be 66° to 67°.

[0113] Therefore, when the backlight unit 220 is viewed from a side direction at an angle to the front, the backlight unit 220 may appear greenish 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 backlight unit 220 to have a uniform color distribution.

[0114] By guiding the light that spreads laterally to emit light forward, the green color that is widely emitted in the lateral direction will be 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.

[0115] Figure 7 is a cross-sectional view illustrating one embodiment of a backlight unit 220 according to one aspect of the present disclosure.

[0116] According to the present disclosure, Figure 7 As shown, a diffusion layer 223 surrounding the lateral surface of the LED 222 may be added to guide the light emitted in the lateral direction forward. The diffusion layer 223 is located on 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 diffusion 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 thereon in an array. In this case, the diffusion 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.

[0117] The diffusion 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 lateral sides except for the top surface of the LED 222 .

[0118] The diffusion layer 223 may be formed by applying a white resin containing a silicone diffusing agent to fill the space between the LEDs 222. The lateral side of the diffusion layer 223 is in close contact with the LEDs 222. Figure 7The top surface of the layer may be 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 diffusion layer 223 .

[0119] 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.

[0120] The diffusion layer 223 may be formed of a silicone epoxy resin containing a diffusing agent in the form of TiO2, SiO2 or ZrO2. Figure 7 The diffusion layer 223 shown in (a) reflects light emitted from the LED 222.

[0121] 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, and the brightness can be improved.

[0122] [Table 1]

[0123] color Diffusion layerX Diffusion layer O Green (G) 0.729 0.835(15％↑) Red (R) 0.813 0.88(8％↑) Blue (B) 0.82 0.87(6％↑)

[0124] Table 1 shows the light efficiency of colors depending on the presence / absence of the diffusion layer 223. In the presence of the diffusion layer 223, the light efficiency of all colors can be improved, resulting in an overall increase in light efficiency of more than 10%.

[0125] Specifically, in the case of green, the brightness is significantly improved due to the high proportion of forward reflection of 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.

[0126] A black dye layer 224 may also be provided on the top surface of the diffusion layer 223. The black dye layer 224 may be a resin layer containing a dark material such as carbon, and thus may absorb light. In the case where the diffusion layer 223 is exposed on the front side, external light may be reflected by the diffusion layer 223, thereby reducing the visibility of the image output from the display device 100.

[0127] The black dye 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 (i.e., a power-off state), it can increase the black contrast of the front surface of the display device 100.

[0128] However, since the black dye layer 224 has absorbed light, if the layer overlaps with the LED 222 or has a large area, it may prevent the light emitted by the LED 222 from being passed forward.

[0129] Therefore, the black dye layer 224 may be manufactured to be positioned on the lateral side of the LED 222 so as not to cover the front of the LED 222 , and may be formed on the top surface of the diffusion layer 223 .

[0130] like Figure 7 In the embodiment shown in (b), a transparent resin layer 225 may be formed by applying a transparent resin to cover the black dye layer 224 and the LED 222. The transparent resin layer 225 may include a silicone or epoxy material. The transparent resin may protect the LED 222 and the applied black dye layer 224, and may make the front surface of the display device 100 flat.

[0131] In order to prevent light reflection of external light, the film layer 226 may be added by laminating at least one of an anti-reflection (AR) (or anti-glare (AG)) film, a low reflection (LR) film, or an anti-fingerprint (AF) film on the front of the transparent resin layer 225 .

[0132] The transparent resin layer 225 and the film layer 226 are only Figure 7 The embodiment (b) is shown, but is also applicable to the case where Figure 7 (a) shows an embodiment in which the diffusion layer 223 is formed by a molding method. Figure 8 is an example Figure 7 Graph of the beam angles of specific colors of LEDs 222. A diffusion layer 223 may be used to narrow the beam angle toward the front side to 60.5° for green, 57.5° for red, and 57° for blue.

[0133] Since the diffusion layer 223 located at the lateral side reflects light forward, the beam angle can be narrower than in the embodiment without the diffusion layer 223. It can be seen that in the absence of the diffusion layer 223, the difference between the maximum and minimum values ​​of the beam angle is about 6°, but by adding the diffusion layer 223, it is reduced to about 3.5°.

[0134] [Table 2]

[0135] color Diffusion layerX Diffusion layer O Green (G) 72° 60.5° Red (R) 66° 57.5° Blue (B) 66.5° 57° Δ Angle 6° 3.5°

[0136] 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.

[0137] 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 .

[0138] The beam angle tends to be inversely proportional to the distance f from the emitting surface to each light emitting chip 2223. Therefore, green, which has the shortest distance, has the largest beam angle. A correction lens 227 may be added to further reduce the beam angle of green.

[0139] Fig. 9 is a diagram illustrating another embodiment of a backlight unit 220 according to an aspect of the present disclosure.

[0140] The figure illustrates an LED 222 of a backlight unit 220 that further includes a correction lens 227. The correction lens 227 may be positioned on a top surface of the LED 222, such as Fig. 9 The correction lens 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° to about 57.5°.

[0141] In the case where the correction lens 227 is installed, the black dye layer 224 may be omitted. Alternatively, the black dye layer 224 may be formed after forming the correction lens 227. The black dye layer 224 may be configured to be positioned on a lateral side of the correction lens 227.

[0142] The correction lens 227 may have a diameter greater than or equal to the diagonal dimension of the LED 222 , and may employ an anamorphic lens having a rectangular boundary corresponding to the shape of the rectangular LED 222 .

[0143] By using the correction lens 227 which is larger than the LED 222, the boundary of the LED 222 and the diffusion layer 223 may be covered, which may improve the bonding force and provide a larger contact area, thereby enhancing the fixing force of the lens.

[0144] The lens may be formed over the LED 222 by a spraying process and may be formed of transparent silicone. It may include a diffuser such as TiO2, SiO2 or ZrO2 for more effective beam angle adjustment and light synthesis.

[0145] In order to make the correction lens 227 have a rectangular border, the corners of the rectangle may be filled using a solvent having a low viscosity in silicone.

[0146] Fig.102 are diagrams illustrating the shape of the numerical aperture (NA) output by color according to the presence / absence of the correction lens 227, wherein (a) illustrates an embodiment without the correction lens 227, and (b) illustrates an embodiment with the correction lens 227.

[0147] 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.

[0148] Referring to (b) showing the NA of an embodiment including the correction lens 227, the NAs of the colors are similar in size and have a uniform square shape.

[0149] Fig.11 2 is a diagram illustrating a specific color beam angle of light emitted from an LED 222 including a correction lens having a diffuser added thereto. The beam angle is reduced and has a uniform shape rather than a shape that is greatly diffused in the lateral direction. In addition, uniform white light can be obtained because the color difference is small.

[0150] As described above, one embodiment of the present disclosure can provide a display device 100 using a semiconductor light emitting element that can reflect light emitted from a 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.

[0151] 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.

[0152] The above description is merely an example of the technical concept of the present disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the spirit and scope of the present disclosure.

[0153] 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.

[0154] 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 backlight unit, comprising: a base substrate, the base substrate comprising circuit wiring; A plurality of light emitting diodes, wherein the plurality of light emitting diodes are arranged in an array on the base substrate; a diffuser layer positioned around a lateral surface of the light emitting diode; as well as A correction lens is positioned on a top surface of the light emitting diode.

2. The backlight unit according to claim 1, wherein: The correction lens is greater than or equal to the diagonal length of the light emitting diode.

3. The backlight unit according to claim 1, wherein: The correction lenses each include a silicone diffuser including at least one of TiO2, SiO2, or ZrO2.

4. The backlight unit according to claim 1, wherein: The correction lens has a height to diameter ratio less than or equal to 0.

3.

5. The backlight unit according to claim 1, wherein: The correction lens includes a square anamorphic lens.

6. The backlight unit according to claim 1, wherein: The light emitting diode includes a light emitting diode including red, blue and green light emitting chips.

7. The backlight unit according to claim 6, wherein: The light emitting diode is a stacked light emitting diode having red, blue and green colors stacked on the base substrate.

8. The backlight unit according to claim 1, wherein: The diffusion layer includes a silicone diffuser including at least one of TiO2, SiO2 or ZrO2, The diffusion layer reflects and diffuses light emitted from the lateral side of the light emitting diode.

9. The backlight unit according to claim 1, wherein: The diffusion layer has a white color.

10. The backlight unit according to claim 1, wherein: The diffusion layer includes a black dye layer positioned on a top surface of the diffusion layer and on a lateral surface of the correction lens.

11. The backlight unit according to claim 10, wherein: The black dye layer includes carbon or an ultraviolet absorbing material.

12. The backlight unit according to claim 10, wherein: The black dye layer is arranged not to overlap the top surface of the light emitting diode.

13. The backlight unit according to claim 10, further comprising: A transparent resin layer covers the black dye layer and the light emitting diode.

14. The backlight unit 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.

15. A display device, comprising: Display panel; a backlight unit configured to provide light to the display panel, Wherein, the backlight unit comprises: a base substrate, the base substrate comprising circuit wiring; A plurality of light emitting diodes, wherein the plurality of light emitting diodes are arranged in an array on the base substrate; a diffuser layer positioned around a lateral surface of the light emitting diode; and A correction lens is positioned on a top surface of the light emitting diode.

16. The display device according to claim 15, wherein: The correction lens is greater than or equal to the diagonal length of the light emitting diode.

17. The display device according to claim 1, wherein: The correction lenses each include a silicone diffuser including at least one of TiO2, SiO2, or ZrO2.

18. The display device according to claim 1, wherein: The correction lens has a height to diameter ratio less than or equal to 0.

3.

19. The display device according to claim 1, wherein: The correction lens includes a square anamorphic lens.

20. The display device according to claim 1, wherein: The light emitting diode comprises a light emitting diode including red, blue and green light emitting chips, The light emitting diode is a stacked light emitting diode having red, blue and green colors stacked on the base substrate.

Images