Light-emitting diode

Abstract

A light emitting diode that emits light in a red wavelength band is disclosed. The light emitting diode includes a first semiconductor layer having a light emitting surface, a second semiconductor layer, an active layer provided between the first semiconductor layer and the second semiconductor layer, a first contact electrode connected to the first semiconductor layer, a second contact electrode connected to the second semiconductor layer, a first connection pad connected to the first contact electrode, and a second connection pad connected to the second contact electrode, and a current concentration region may be located between the first connection pad and the second connection pad.

Description

[Technical field]

[0001] The present invention relates to a light emitting diode, and more particularly to a light emitting diode that emits light in the red wavelength band. [Background technology]

[0002] The display panel includes a substrate and a plurality of light emitting diodes mounted on the substrate, the light emitting diodes being inorganic self-emitting light emitting diodes.

[0003] A number of light emitting diodes mounted on a substrate operate as pixels or sub-pixels to display a variety of colors. Each pixel or sub-pixel is controlled by a number of thin film transistors (TFTs). Each light emitting diode emits a variety of hues, for example, red, green, and blue. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a light-emitting diode in which a current concentration region is positioned in the center of the light-emitting surface and the amount of light emitted on the left and right sides is substantially symmetrical. [Means for solving the problem]

[0005] According to various embodiments of the present invention, to achieve the above object, there is provided a light emitting diode including a first semiconductor layer having a light emitting surface, a second semiconductor layer, an active layer provided between the first semiconductor layer and the second semiconductor layer, a first contact electrode connected to the first semiconductor layer, a second contact electrode connected to the second semiconductor layer, a first connection pad connected to the first contact electrode, and a second connection pad connected to the second contact electrode, wherein a current concentration region is located between the first connection pad and the second connection pad.

[0006] The second contact electrode may be located between the first connection pad and the second connection pad.

[0007] The second contact electrode may be connected to the second connection pad by a conductive connection member.

[0008] The second contact electrode may be disposed at a position corresponding to the center of a long side of the light emitting diode.

[0009] The second contact electrode may be disposed at a position corresponding to the center of the light emitting surface.

[0010] The second contact electrode may be disposed at a position corresponding to the center of the active layer.

[0011] The second contact electrode is an opaque conductive material, and the conductive connecting member may be made of an opaque conductive material or a transparent electrode material.

[0012] The second contact electrode may be located within a region of a conductive connecting member.

[0013] The first contact electrode may be disposed at a position corresponding to the first connection pad, and the second contact electrode may be disposed at a position not corresponding to the second connection pad.

[0014] The second contact electrode may have one end connected to the second connection pad and the other end extending in a direction facing the first connection pad.

[0015] The other end of the second contact electrode may be spaced apart from the first connection pad.

[0016] The second contact electrode may be made of an opaque conductive material.

[0017] The second contact electrode may be finger-shaped.

[0018] The active layer may emit light in the red wavelength range.

[0019] The area of ​​the second contact electrode may be 1.9% to 3.2% of the area of ​​the light emitting surface. [Brief description of the drawings]

[0020] [Figure 1] 1 is a block diagram showing a display device according to an embodiment of the present invention; [Diagram 2] 1 is a plan view showing a light emitting diode according to an embodiment of the present invention; [Diagram 3] 3 is a cross-sectional view taken along line AA' shown in FIG. 2. [Figure 4] FIG. 4 is an enlarged view showing a portion B shown in FIG. 3. [Diagram 5] 4 is a schematic diagram showing an example in which a current concentration region of a light emitting diode according to an embodiment of the present invention is located at the center of the light emitting diode; [Figure 6] FIG. 4 is a cross-sectional view showing a light-emitting diode according to another embodiment of the present invention. [Figure 7] FIG. 11 is a plan view showing a light-emitting diode according to still another embodiment of the present invention. [Figure 8] 8 is a cross-sectional view taken along line CC' shown in FIG. 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Various embodiments will be described in more detail below with reference to the accompanying drawings. The embodiments described in this specification may be modified in various ways. Specific embodiments may be depicted in the drawings and described in detail in the detailed description. However, the specific embodiments disclosed in the accompanying drawings are intended to facilitate understanding of the various embodiments. Therefore, the technical idea is not limited by the specific embodiments disclosed in the accompanying drawings, and should be understood as including all equivalents or alternatives included in the idea and technical scope of the invention.

[0022] In the present disclosure, terms including ordinal numbers, such as first and second, may be used to describe various components, but such components are not limited to the above-mentioned terms. The above-mentioned terms are used only to distinguish one component from another component.

[0023] In this disclosure, terms such as "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but should be understood as not precluding the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to the other component, but that there may be other components in between. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

[0024] In the present disclosure, the expression "similar" does not only mean a perfect match, but also means a degree of difference including the range of error in processing.

[0025] In addition, in describing the present disclosure, if it is determined that a specific description of a related known function or configuration unnecessarily obscures an element of the present disclosure, the detailed description thereof will be shortened or omitted.

[0026] In the present disclosure, a display module may include a display panel having inorganic light emitting diodes for displaying images. Here, the display panel may be a flat panel display panel or a curved display panel. For example, the display panel may include a plurality of inorganic light emitting diodes (hereinafter, micro LEDs) having a size of about 100 μm or less, thereby providing better contrast, response time, and energy efficiency than a liquid crystal display (LCD) that requires a backlight.

[0027] In the present disclosure, the micro LED mounted on the display panel has a higher brightness, light emitting efficiency, and lifespan than an OLED. The micro LED may be a semiconductor chip that can emit light by itself when power is supplied. The micro LED has a fast response speed, low power, and high brightness. For example, the micro LED has a higher efficiency of converting electricity into photons than an LCD or OLED. That is, the micro LED has a higher "brightness per watt" than an LCD or OLED display. The micro LED can produce the same brightness with only about half the energy compared to an LED or OLED, which has a width, length, and height of more than about 100 μm. The micro LED can achieve high resolution, excellent hue, brightness, and brightness, and can accurately express a wide range of hues, and can realize a clear screen even outdoors where the sunlight is strong. In addition, the micro LED is resistant to the burn-in phenomenon and generates little heat, so that a long lifespan is guaranteed without deformation. The micro LED may have a flip chip structure in which an anode electrode and a cathode electrode are formed on the same surface, and a light emitting surface is located on the opposite side to the surface on which the anode electrode and the cathode electrode are formed.

[0028] In the present disclosure, the display panel may include a glass substrate, a substrate made of a synthetic resin having flexibility (e.g., PI (polyimide), PET (polyethylene terephthalate), PES (polyether sulfone), PEN (polyethylene naphthalate), PC (polycarbonate), etc.), or a ceramic substrate.

[0029] In the present disclosure, the substrate may have a TFT (thin film transistor) circuit formed on its front surface, and a power supply circuit for supplying power to the TFT circuit, a data driver, a gate driver, and a timing controller for controlling each driver disposed on its rear surface. A plurality of pixels arranged on the front surface of the substrate may be driven by the TFT circuit.

[0030] In the present disclosure, the substrate may not have a circuit disposed on the back surface, in which case the TFT circuit may be fabricated in a film form and attached to the front surface of the substrate (in this case, the substrate may be a glass substrate).

[0031] In the present disclosure, the TFT provided on the substrate is not limited to a specific structure or type. For example, the TFT referred to in the present disclosure may be an a-Si (amorphous silicon) TFT, an LTPS (low temperature polycrystalline silicon) TFT, an LTPO (low temperature polycrystalline oxide) TFT, a HOP (hybrid oxide and polycrystalline silicon) TFT, an LCP (liquid crystalline polymer) TFT, an OTFT (organic TFT), or a graphene TFT. Alternatively, the substrate may be applied with only a P-type (or N-type) MOSFET (metal oxide semiconductor field effect transistor) in a Si wafer CMOS (complementary metal oxide silicon) process.

[0032] In the present disclosure, the front surface of the substrate may be divided into an active region and a non-active region. The active region may correspond to an area occupied by the TFT layer on the front surface of the substrate, and the non-active region may correspond to an area other than the area occupied by the TFT layer on the front surface of the substrate.

[0033] In the present disclosure, the substrate may include an edge region corresponding to an outer periphery. The edge region of the substrate may be a remaining region of the substrate excluding a region in which a circuit is formed. The edge region of the substrate may include a part of a front surface of the substrate adjacent to a side surface of the substrate and a part of a rear surface of the substrate adjacent to the side surface of the substrate. The substrate may be formed in a quadrangle type. For example, the substrate may be formed in a rectangle or a square. The edge region of the substrate may include at least one of the four sides of the substrate.

[0034] In the present disclosure, the substrate may be a substrate without a TFT layer. In this case, the substrate may include a plurality of micro integrated circuits (ICs) that can function as TFTs. In this case, the substrate may be formed with wiring that electrically connects the plurality of micro ICs and the micro LEDs.

[0035] In the present disclosure, the pixel driving method of the display module may be an active matrix (AM) driving method or a passive matrix (PM) driving method. The display module may form a wiring pattern to which each micro LED is electrically connected according to the AM driving method or the PM driving method.

[0036] In the present disclosure, the display module may be installed and applied as a single unit in a wearable device, a portable device, a handheld device, and various electronic products and electrical equipment requiring displays, and may be applied to display devices such as monitors for personal computers (PCs), high-definition televisions, signage (or digital signage), electronic displays, etc. through multiple assembly arrangements in a matrix type.

[0037] Hereinafter, with reference to the accompanying drawings, an embodiment of the present disclosure will be described in detail so that a person having ordinary skill in the art to which the present disclosure belongs can easily carry out the embodiment. The present disclosure may be realized in various different forms and is not limited to the embodiments described herein. In addition, in order to clearly explain the present disclosure in the drawings, parts that are not related to the description are omitted, and similar parts are designated by similar drawing reference numerals throughout the specification.

[0038] Hereinafter, display devices according to various embodiments of the present disclosure will be described with reference to the drawings.

[0039] FIG. 1 is a block diagram showing a display device according to an embodiment of the present invention.

[0040] The display device 1 of the present disclosure may include a plurality of display modules 3. In this case, the plurality of display modules 3 may be physically connected to realize a large display (for example, a large format display (LFD)).

[0041] Referring to FIG. 1, a display device 1 according to an embodiment of the present disclosure may include a display module 3 and a processor 5.

[0042] The display module 3 according to an embodiment of the present disclosure can display various images. Here, the image is a concept including still images and / or moving images. The display module 3 may display various images such as broadcast content, multimedia content, etc. In addition, the display module 3 may display a user interface and icons.

[0043] The display module 3 may include a display panel 10 and a display driver integrated circuit (DDI) 7 for controlling the display panel 10 .

[0044] The display driver IC 7 may include an interface module 7a, a memory 7b (e.g., a buffer memory), an image processing module 7c, or a mapping module 7d. The display driver IC 7 may receive video information, including, for example, video data or video control signals corresponding to instructions for controlling the video data, from another component of the display device 1 via the interface module 7a. For example, according to one embodiment, the video information may be received from the processor 5 (e.g., a main processor (e.g., an application processor)) or a sub-processor (e.g., a graphics processing unit) that operates independently of the function of the main processor.

[0045] The display driver IC 7 may communicate with a sensor module (not shown) via the interface module 7a. The display driver IC 7 may store at least a portion of the received image information in the memory 7b, for example, on a frame-by-frame basis. The image processing module 7c may, for example, pre-process or post-process (e.g., adjust resolution, brightness, or size) at least a portion of the image data based at least on characteristics of the image data or characteristics of the display panel 10. The mapping module 7d may generate a voltage value or a current value corresponding to the image data pre-processed or post-processed via the image processing module 7c. According to an embodiment, the generation of the voltage value or current value may be performed at least in part based on properties of pixels of the display panel 10, for example, an arrangement of pixels (RGB stripe or pentile structure) or a size of each sub-pixel. At least a portion of the pixels of the display panel 10 may be driven at least in part based on the voltage value or current value, so that visual information (e.g., text, image, or icon) corresponding to the image data may be displayed via the display panel 10.

[0046] The display driver IC 7 may transmit drive signals (eg, driver drive signals, gate drive signals, etc.) to the display based on the video information received from the processor 5.

[0047] The display driver IC7 may display an image based on the image signal received from the processor 5. As an example, the display driver IC7 may display an image by generating drive signals for a plurality of sub-pixels based on the image signal received from the processor 5 and controlling light emission of the plurality of sub-pixels based on the drive signals.

[0048] The display module 3 may further include a touch circuit (not shown). The touch circuit may include a touch sensor and a touch sensor IC for controlling the same. The touch sensor IC may control the touch sensor to detect touch input or hover input for a specified position on the display panel 10. For example, the touch sensor IC may detect the touch input or hover input by measuring a change in a signal (e.g., voltage, light amount, resistance, or charge amount) for a specified position on the display panel 10. The touch sensor IC may provide information (e.g., position, area, pressure, or time) about the detected touch input or hover input to the processor 5. According to an embodiment, at least a part of the touch circuit (e.g., the touch sensor IC) may be included in the display driver IC 7, or as part of the display panel 10, or as part of another component (e.g., a sub-processor) located outside the display module 3.

[0049] The processor 5 may be implemented as a digital signal processor (DSP) for processing digital video signals, a microprocessor, a graphics processing unit (GPU), an artificial intelligence (AI) processor, a neural processing unit (NPU), or a time controller (TCON). However, without being limited thereto, the processor 5 may include or be defined as one or more of a central processing unit (CPU), a micro controller unit (MCU), a micro processing unit (MPU), a controller, an application processor (AP), a communication processor (CP), or an ARM processor. The processor 5 may be implemented as a system on chip (SoC) or large scale integration (LSI) incorporating a processing algorithm, or as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

[0050] The processor 5 may run an operating system or an application program to control hardware or software components connected to the processor 5, and may perform various data processing and calculations. In addition, the processor 5 may load instructions or data received from at least one of the other components into a volatile memory for processing, and may store various data in a non-volatile memory.

[0051] The display panel 10 may include a substrate and a plurality of pixels. The substrate may include a pixel region in which a plurality of pixels are arranged. A pixel may be arranged in each pixel region. A pixel may include a plurality of sub-pixels. For example, the sub-pixels may include a first light emitting diode that emits light in a red wavelength band, a second light emitting diode that emits light in a green wavelength band, and a third light emitting diode that emits light in a blue wavelength band. The first to third light emitting diodes may be, for example, micro LEDs (light emitting diodes) having a size of about 100 μm or less as inorganic light emitting elements. In this case, the first to third light emitting diodes may be flip chip types in which an anode connection pad and a cathode connection pad are arranged together on the opposite side of the light emitting surface.

[0052] In one pixel region, a plurality of thin film transistors (TFTs) for driving the first to third micro light-emitting diodes may be arranged in a portion not occupied by the first to third micro light-emitting diodes.

[0053] The first to third light emitting diodes may be arranged in a row at regular intervals within one pixel region, but are not limited thereto. For example, the first to third light emitting diodes may be arranged in an L-shape or in a pentile RGBG manner. The pentile RGBG manner is a manner in which the numbers of red, green and blue sub-pixels are arranged in a ratio of 1:1:2 (RGBG) based on the characteristic that humans have low discrimination ability for blue and highest discrimination ability for green. The pentile RGBG manner is effective because it can increase yield, reduce unit cost and realize high resolution on a small screen.

[0054] FIG. 2 is a plan view showing an LED according to one embodiment of the present invention, FIG. 3 is a cross-sectional view taken along line A-A' in FIG. 2, and FIG. 4 is an enlarged view showing portion B in FIG. 3.

[0055] 2 and 3, a light emitting diode 100 according to an embodiment of the present disclosure may be a red light emitting diode that emits light in a red wavelength band.

[0056] A light emitting diode 100 according to one embodiment of the present disclosure may include a first semiconductor layer 111, a second semiconductor layer 113, and an active layer 115 provided between the first semiconductor layer 111 and the second semiconductor layer 113.

[0057] The first semiconductor layer 111, the active layer 115, and the second semiconductor layer 113 may be formed using methods such as metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), or plasma-enhanced chemical vapor deposition (PECVD).

[0058] The first semiconductor layer 111 may include, for example, a p-type semiconductor layer (anode). The p-type semiconductor layer may be selected from, for example, GaAs, GaP, GaAlAs, or InGaAlP.

[0059] The active layer 115 is a region where electrons and holes recombine, and when the electrons and holes recombine, they can transition to a lower energy level and generate light having a corresponding wavelength.

[0060] The active layer 115 may include a semiconductor material, such as amorphous silicon or poly crystalline silicon, or may include an organic semiconductor material and may be formed in a single quantum well structure or a multi quantum well (MQW) structure.

[0061] The second semiconductor layer 113 may include, for example, an n-type semiconductor layer (cathode). The n-type semiconductor layer may be selected from, for example, GaAs, GaP, GaAlAs, or InGaAlP.

[0062] The light emitting diode 100 according to an embodiment of the present disclosure may have a hole type mesa structure. In this case, the first connection pad 151 may be connected to the first semiconductor layer 111 through a hole penetrating the second semiconductor layer 113 and the active layer 115.

[0063] When a hole-type mesa structure is applied to the light-emitting diode 100, a part of the active layer 115 may be exposed to the outside. The exposed part of the active layer 115 may be protected by a passivation layer 170.

[0064] The passivation layer 170 may prevent the active layer 115 from being exposed to the outside, and may also protect the outside of the light emitting diode 100 from the external environment, such as moisture and oxygen.

[0065] The passivation layer 170 may cover one side of the light-emitting diode 100 on which the first connection pad 151 and the second connection pad 153 are located (e.g., the side opposite the light-emitting surface 112 of the light-emitting diode 100) and an edge portion of the active layer 115.

[0066] Although not shown in the drawings, the passivation layer 170 may also cover the side surfaces of the first semiconductor layer 111 .

[0067] The first contact electrode 131 may be made of an opaque metal (eg, Al, Pt, Au, Cu or Cr) for ohmic contacts between the first semiconductor layer 111 and the first connection pad 151.

[0068] A first contact electrode 131 may have a portion in contact with the first contact electrode 131 and another portion disposed on a passivation layer 170 covering the second semiconductor layer 113 .

[0069] The second contact electrode 133 may be electrically connected to the second connection pad 153 via the conductive connection member 140. The second contact electrode 133 may be made of an opaque metal (e.g., Al, Pt, Au, Cu, or Cr).

[0070] The area of ​​the second contact electrode 133 may be determined to be an optimal area proportional to the area of ​​the light emitting surface 122 (or the area of ​​the active layer 115) of the light emitting diode 100. In this case, if the area of ​​the second contact electrode 133 is smaller than the optimal area, the operating voltage (VF) increases due to a decrease in current injection efficiency, whereas if the area is larger than the optimal area, the current crowding effect decreases (sidewall leakage), which may decrease the light efficiency.

[0071] For example, when the TFT provided in the display panel 10 of the present disclosure is driven by a PWM (pulse width modulation) driving method and a low current of 150 μA or less, the optimal area range of the second contact electrode 133 is 1.9% to 3.2% of the area of ​​the light-emitting surface 112 of the light-emitting diode 100, which can ensure optimal efficiency characteristics.

[0072] The second contact electrode 133 may be disposed at a position spaced apart from the second connection pad 153. For example, the second contact electrode 133 may be located between the first connection pad 151 and the second connection pad 153.

[0073] The light emitting surface 112 of the light emitting diode 100 may be a rectangle having a length (L1) and a width (W1), as shown in Figure 2. In this case, the length (L1) may be greater than the width (W1).

[0074] The second contact electrode 133 may be located on the second semiconductor layer 113 corresponding to approximately the center of the light emitting surface 112 of the light emitting diode 100 .

[0075] For example, the center of the second contact electrode 133 may be located at a position corresponding to a predetermined length (L2) from one side of the light emitting diode 100. Or, the center of the second contact electrode 133 may be located at a position corresponding to a predetermined length (L3) from the other side of the light emitting diode 100. In this case, L2 and L3 may be substantially the same length.

[0076] The length from the center of the second contact electrode 133 to the left side may be the same as the length from the center of the second contact electrode 133 to the right side. Alternatively, the left and right portions of the second contact electrode 133 may be formed symmetrically with respect to the center of the second contact electrode 133.

[0077] The second contact electrode 133 disposed in the center of the light-emitting diode 100 may be electrically connected to the second connection pad 153 via the conductive connection member 140. In this case, the second contact electrode 133 may be disposed inside the conductive connection member 140 so as not to come off from the conductive connection member 140.

[0078] The conductive connection member 140 may be formed of a rectangle having a large ratio of the length of its long side to its short side. For example, the ratio of the length of the long side to the length of the short side of the conductive connection member 140 may be, but is not limited to, about 4:1 to 6:1.

[0079] The length (L4) of the conductive connection member 140 may be greater than the length (L5) of the second contact electrode 133. In this case, when the second contact electrode 133 has a circular shape, the length (L5) may be the diameter of the second contact electrode 133.

[0080] The area of ​​conductive connection member 140 may be smaller than the area of ​​second connection pad 153. For example, when the length (L1) of light emitting surface 112 of light emitting diode 100 is approximately 58 μm, the width (W1) of light emitting surface 112 of light emitting diode 100 is approximately 34 μm, and the length (L5) of second contact electrode 133 is approximately 7 μm to 9 μm, the length L4 of conductive connection member 140 may be approximately 10 to 25 μm, and the width (W2) of conductive connection member 140 may be approximately 9 μm to 11 μm.

[0081] The area (L4×W2) of conductive connecting member 140 may be optimally determined by taking into consideration the area (L1×W1) of light-emitting surface 112 of light-emitting diode 100 and the length or diameter of second contact electrode 133.

[0082] The outer periphery of the second contact electrode 133 disposed on one side of the conductive connection member 140 may be spaced apart from the outer periphery of the conductive connection member 140 by a distance of about 1 μm from the inner side of the conductive connection member 140, but is not limited thereto.

[0083] On the other hand, the conductive connecting member 140 does not need to be limited to a specific length (e.g., L1), width (e.g., W2), or shape, and may have various shapes and areas such that the second contact electrode 133 is located at a position corresponding to the center of the light emitting surface 112 of the light emitting diode 100.

[0084] The conductive connection member 140 may be made of a material that has metallic conductive properties and low ohmic properties of the second semiconductor layer 113. For example, the conductive connection member 140 may be made of a transparent electrode material (e.g., ITO or ZnO) or an opaque electrode material (e.g., Al, Pt, Au, Cu, or Cr).

[0085] The first connection pad 151 and the second connection pad 153 may be disposed at a distance from each other on opposite sides of the light emitting diode 100 from the light emitting surface 112 .

[0086] The first connection pad 151 may be disposed on the second semiconductor layer 113 for electrical connection between the first semiconductor layer 111 and a connection pad (not shown) of a substrate. In this case, the first connection pad 151 may be electrically connected to the first semiconductor layer 111 via the first contact electrode 131.

[0087] The second connection pad 153 may be disposed on the second semiconductor layer 113 for electrical connection between the second semiconductor layer 113 and a connection pad (not shown) of a substrate. In this case, the second connection pad 153 may be physically and electrically connected to the second contact electrode 133.

[0088] The first connection pad 151 and the second connection pad 153 may be made of Au or an alloy containing Au, but are not limited thereto.

[0089] The passivation layer 170 is an inorganic insulating film (e.g., silicon oxide (SiO 2 ) and / or an organic insulating film (for example, a common general-purpose polymer (PMMA or PS)). Thus, the passivation layer 170 may be a composite laminate structure of an inorganic insulating film and an organic insulating film.

[0090] 4, in the light emitting diode 100 according to the embodiment of the present disclosure, uneven portions 114 formed in an uneven pattern with equal or uneven intervals may be formed on a light emitting surface 112 provided on a first semiconductor layer 111. In the light emitting diode 110 according to the embodiment of the present disclosure, the uneven portion 114 of the light emitting surface 112 may increase the maximum crest area and increase the critical angle of light emission, thereby improving light emitting efficiency.

[0091] In this case, in the light-emitting diode 100 according to the embodiment of the present disclosure, the passivation layer 180 may cover the uneven portion 114 to protect the light-emitting surface 112 .

[0092] FIG. 5 is a schematic diagram showing an example in which a current concentration region of a light emitting diode according to an embodiment of the present invention is located at the center of the light emitting diode.

[0093] Referring to FIG. 5, the light emitting diode 100 may emit light in the red wavelength band at the active layer 115 when a current 132 flows from the first connection pad 151 to the second connection pad 153 .

[0094] The second contact electrode 133 is a location where current is concentrated, and a portion of the active layer 115 corresponding to the second contact electrode 133 may become an emission concentration region.

[0095] The light-emission concentration region in the active layer 115 can be a location corresponding to the position of the second contact electrode 133. Therefore, since the second contact electrode 133 is at a location corresponding to the center of the light-emitting surface 112 of the light-emitting diode 100, the light-emission concentration region in the active layer 115 can be at a location corresponding to the center of the light-emitting surface 112 of the light-emitting diode 100.

[0096] In this manner, the light-concentrated region may be located at the center of the light-emitting surface 112 of the light-emitting diode 100. As a result, the light-concentrated region is not biased to the left or right side of the light-emitting surface 112 of the light-emitting diode 100, so that the amounts of light emitted to the left and right of the light-emitting surface 112 of the light-emitting diode 100 may be substantially symmetrical, as shown in FIG.

[0097] Therefore, the light-emitting diode 100 according to the embodiment of the present disclosure can improve left and right full white color deviation when observed at the same angle (or similar angle) on the left and right sides of the light-emitting surface 112. That is, the white balance can be improved by improving the luminance deviation according to the user's viewing direction (for example, the direction in which the user views the display device 1 from the front, left, or right side of the display device 1).

[0098] FIG. 6 is a cross-sectional view showing a light emitting diode according to another embodiment of the present invention.

[0099] A light emitting diode 100a according to another embodiment of the present disclosure has many configurations substantially similar to those of the above-described light emitting diode 100, but has some configurations different from those of the above-described light emitting diode 100. Therefore, in the following description of the light emitting diode 100a, the description of the configurations similar to those of the above-described light emitting diode 100 will be omitted, and the description will focus on the configurations different from those of the above-described light emitting diode 100.

[0100] 6, an edge type mesa structure may be applied to a light emitting diode 100a according to another embodiment of the present disclosure. In this case, the first connection pad 151a may extend along the side surfaces of the second semiconductor layer 113a and the active layer 115a. The first connection pad 151a may be electrically connected to the first semiconductor layer 111a via the first contact electrode 131a.

[0101] The second contact electrode 133a may be located on the second semiconductor layer 113a corresponding to approximately the center of the active layer 115a.

[0102] For example, the center of the second contact electrode 133a may be located at a position corresponding to a predetermined length (L12) from one side of the active layer 115a. Alternatively, the center of the second contact electrode 133a may be located at a position corresponding to a predetermined length (L13) from the other side of the active layer 115a. In this case, L12 and L13 may be substantially the same length.

[0103] In this case, the center of the active layer 115a may coincide with the center of the light emitting surface 112a of the light emitting diode 100a. Or, the center of the active layer 115a may be shifted a predetermined distance to the left or right from the center of the light emitting surface 112a of the light emitting diode 100a. As described above, the center of the second contact electrode 133a may be located at a position corresponding to the center of the active layer 115a. Therefore, the center of the second contact electrode 133a may correspond to the center of the light emitting surface 112a of the light emitting diode 100a, or may correspond to a point slightly offset to the left or right from the center of the light emitting surface 112a.

[0104] Since the current is concentrated on the second contact electrode 133a, the current concentration region of the light emitting diode 100a may be a point that corresponds to approximately the center of the light emitting surface 112a of the light emitting diode 100a. As a result, the light concentration region is not arranged so as to be biased to the left or right side of the light emitting surface 112a of the light emitting diode 100a, so that the amount of light emitted to the left and right from the light emitting surface 112a of the light emitting diode 100a can be approximately symmetrical.

[0105] Therefore, like the above-mentioned light-emitting diode 100, the light-emitting diode 100a according to another embodiment of the present disclosure can also improve the left and right full white color deviation when observed at the same angle (or a similar angle) on the left and right sides of the light-emitting surface 112a, thereby improving the left and right white balance of the display device 1.

[0106] In FIG. 6, the unexplained reference numeral 140a denotes a conductive connecting member, 151a denotes a first connecting pad, 153a denotes a second connecting pad, 170a denotes a passivation layer, L11 denotes the length of the light-emitting surface 112a, L14 denotes the length of the conductive connecting member 140a, and L15 denotes the length of the second contact electrode 133a.

[0107] FIG. 7 is a plan view showing a light emitting diode according to still another embodiment of the present invention, and FIG. 8 is a cross-sectional view taken along line CC' shown in FIG.

[0108] A light-emitting diode 200 according to yet another embodiment of the present disclosure is substantially similar in many configurations to the above-described light-emitting diode 100, but differs in some configurations. Therefore, in the following description of the light-emitting diode 200, the description of the configurations similar to those of the above-described light-emitting diode 100 will be omitted, and the description will focus on the configurations different from the above-described light-emitting diode 100.

[0109] 7 and 8, the light emitting diode 200 may include a second contact electrode 233 having a first portion 233a and a second portion 233b integrally formed therewith.

[0110] The second contact electrode 233 may be approximately finger-shaped. For example, a first portion 233a of the second contact electrode 233 may be connected to the second connection pad 253. A second portion 233b of the second contact electrode 233 may be formed to extend from the first portion 233a along the second connection pad 253 and be spaced apart from the outer periphery of the second connection pad 253.

[0111] The first portion 233 a of the second contact electrode 233 may be located at a point corresponding to approximately the center of the second connection pad 253 .

[0112] The tip of the second portion 233 b of the second contact electrode 233 may be located at a point corresponding to the center of the light emitting surface 212 of the light emitting diode 200 or adjacent to the center of the light emitting surface 212 of the light emitting diode 200 .

[0113] An end of the second portion 233b of the second contact electrode 233 may be located at a point corresponding to a predetermined length (L22) from the left side of the light emitting diode 200 toward the center of the light emitting diode 200. Alternatively, the end of the second portion 233b of the second contact electrode 233 may be located at a point corresponding to a predetermined length (L23) from the right side of the light emitting diode 200 toward the center of the light emitting diode 200. L22 and L23 may be substantially the same length.

[0114] The width (W22) of the second portion 233b of the second contact electrode 233 may be about 1 μm to 4 μm. If the width W22 of the second portion 233b of the second contact electrode 233 is less than 1 μm, the rate of disconnection defects may increase, and if it exceeds 4 μm, the degree to which the current concentration region is offset from the center of the light emitting surface 212 of the light emitting diode 200 may increase.

[0115] On the other hand, the width (W22) of the second portion 233b of the second contact electrode 233 may be limited to an appropriate range in proportion to the size of the light emitting surface 212 of the light emitting diode 200.

[0116] In Fig. 7, the unexplained reference symbols L21 and W21 respectively indicate the length and width of the light emitting surface 212. In Fig. 8, the unexplained reference symbols 211, 213, 215, 231, 251, and 270 respectively indicate the first semiconductor layer, the second semiconductor layer, the active layer, the first contact electrode, the first connection pad, and the passivation layer.

[0117] As described above, according to various embodiments of the present disclosure, the light-emitting concentrated area is located at the center of the light-emitting surface of the light-emitting diode, and the light-emitting concentrated area can be minimized or improved from being biased to the left or right side of the light-emitting surface of the light-emitting diode. Therefore, by making the amount of light on the left and right sides of the light-emitting surface of the light-emitting diode symmetrical, it is possible to minimize the luminance deviation according to the user's viewing direction and improve the white balance.

[0118] Although the preferred embodiment of the present invention has been described in detail above with reference to the accompanying drawings, the present invention is not limited to the above embodiment. It is clear that a person having ordinary knowledge in the technical field to which the present invention pertains can conceive of various modified or altered examples within the scope of the technical intent described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention.

Claims

1. a first semiconductor layer having a light emitting surface; A second semiconductor layer; an active layer provided between the first semiconductor layer and the second semiconductor layer; a first contact electrode connected to the first semiconductor layer; a second contact electrode connected to the second semiconductor layer; a first connection pad connected to the first contact electrode; a second connection pad connected to the second contact electrode; Including, A light emitting diode, the light emitting diode having a current concentration region located between the first connection pad and the second connection pad.

2. 2. The light emitting diode of claim 1, wherein the second contact electrode is located between the first connection pad and the second connection pad.

3. The light-emitting diode according to claim 2 , wherein the second contact electrode is connected to the second connection pad by a conductive connection member.

4. The light-emitting diode according to claim 3 , wherein the second contact electrode is disposed at a position corresponding to a center of a long side of the light-emitting diode.

5. The light-emitting diode according to claim 3 , wherein the second contact electrode is disposed at a position corresponding to a center of the light-emitting surface.

6. The light-emitting diode according to claim 3 , wherein the second contact electrode is disposed at a position corresponding to a center of the active layer.

7. the second contact electrode is an opaque conductive material; 4. The light-emitting diode according to claim 3, wherein the conductive connecting member is made of an opaque conductive material or a transparent electrode material.

8. The light emitting diode according to claim 3 , wherein the second contact electrode is located within the region of the conductive connecting member.

9. the first contact electrode is disposed at a position corresponding to the first connection pad; The light-emitting diode according to claim 1 , wherein the second contact electrode is disposed at a position not corresponding to the second connection pad.

10. The light-emitting diode according to claim 1 , wherein the second contact electrode has one end connected to the second connection pad and the other end extending in a direction facing the first connection pad.

11. The light-emitting diode according to claim 10 , wherein the other end of the second contact electrode is spaced apart from the first connection pad.

12. 11. The light emitting diode of claim 10, wherein the second contact electrode is made of an opaque conductive material.

13. The light-emitting diode according to claim 10, wherein the second contact electrode has a finger shape.

14. 2. The light emitting diode of claim 1, wherein the active layer emits light in the red wavelength band.

15. 2. The light-emitting diode according to claim 1, wherein an area of ​​the second contact electrode is 1.9% to 3.2% of an area of ​​the light-emitting surface.

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