Display device and manufacturing method thereof

Abstract

A display device includes: a substrate; a plurality of bank patterns disposed on the substrate; at least one recess in one of the plurality of bank patterns; a first electrode disposed in the recess; a reflective layer disposed on the first electrode; a light emitting element disposed on the first electrode; and a first optical layer surrounding a side surface of the light emitting element.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority and benefit of Korean Patent Application No. 10 - 2023 - 0171097, filed on November 30, 2023, which is incorporated herein by reference in its entirety. Technical field

[0003] Embodiments relate to a display device using an inorganic light - emitting diode as a light source and a method of manufacturing the same. Background art

[0004] Electroluminescent display devices include an organic light - emitting display device provided with an organic light - emitting diode (OLED) and an inorganic light - emitting display device (hereinafter referred to as an "LED display device") provided with an inorganic light - emitting diode (hereinafter referred to as an "LED").

[0005] Since an electroluminescent display device uses a self - emitting element to display an image, it does not require a separate light source (e.g., a backlight unit), and thus the electroluminescent display device can be implemented in a thin form and various forms.

[0006] Since the penetration of oxygen and moisture can cause oxidation between the organic light - emitting layer and the electrode, the organic light - emitting display device requires a design to prevent or at least reduce the penetration of oxygen and moisture.

[0007] Recently, as an example of an inorganic light - emitting display device, a micro - LED display device in which micro - LEDs (micro light - emitting diodes) are arranged in pixels has been attracting attention as a next - generation display device. A micro - LED can be an inorganic LED having a size of 100 μm or less. A micro - LED can be manufactured through a separate semiconductor process, and can be transferred to a pixel position on a display panel substrate of a display device and arranged in each sub - pixel by color. Summary of the invention

[0008] The present disclosure provides a display device and a method of manufacturing the same, which can prevent or at least reduce the loss of light - emitting elements during a process of removing and re - coating a first optical layer due to a defect in the first optical layer by transferring the light - emitting elements into recesses formed in a plurality of bank patterns.

[0009] The problems to be solved by the present disclosure are not limited to the above problems, and other problems not mentioned herein will be clearly understood by those skilled in the art from the following description.

[0010] The above problems are solved by a display device, which includes: a substrate; a plurality of bank patterns disposed on the substrate; at least one recess formed in each of the plurality of bank patterns; a first electrode disposed in the recess; a reflective region disposed on the first electrode; a light-emitting element disposed on the first electrode in the recess; and a first optical layer disposed to surround a side surface of the light-emitting element.

[0011] According to the present disclosure, the light-emitting element can be transferred to a bottom surface of a recess in the bank pattern, so that the recess can be used as a breakwater or a dam to prevent or at least reduce loss of the light-emitting element due to water pressure or wind pressure during a process of removing foreign matter or a chemical solution used for removing a defective first optical layer. Therefore, even if a defect appears in the first optical layer, the first optical layer can be removed and coated again to continue production of the product, thereby reducing costs.

[0012] Embodiments disclosed herein also include a display device, including: a substrate; a pixel driving circuit on the substrate; one or more insulating layers on the pixel driving circuit; a bank including a plurality of protrusions on the one or more insulating layers. At least one of the plurality of protrusions includes a recess. The display device further includes a pixel. The pixel includes a plurality of sub-pixels. At least one of the plurality of sub-pixels includes: a first electrode in the recess; a light-emitting element disposed on the first electrode and at least partially located in the recess; and a second electrode on the light-emitting element. An area of a bottom surface of the recess is larger than an area of a bottom surface of the light-emitting element.

[0013] In some embodiments, at least one of the plurality of sub-pixels further includes a reflective layer surrounding a portion where the first electrode and the light-emitting element are in contact with each other. In some embodiments, at least one of the plurality of sub-pixels further includes a reflective layer on a bottom surface and a side surface of the recess. In some embodiments, the display device further includes an optical layer in the recess between the reflective layer and the light-emitting element.

[0014] Various beneficial advantages and effects of the present disclosure are not limited to the above description, and those skilled in the art will clearly understand other effects not mentioned through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Through the detailed description of the exemplary embodiments of the present disclosure with reference to the drawings, the above and other objects, features, and advantages of the present disclosure will become more apparent to those of ordinary skill in the art. In the accompanying

[0016] FIGURES:

[0017] Figure 1 is a diagram showing a display device according to an embodiment of the present disclosure.

[0018] Figure 2is according to an embodiment of the present disclosure Figure 1 An enlarged view of region A.

[0019] Figure 3 is a diagram showing a partial region of a pixel according to an embodiment of the present disclosure;

[0020] Figure 4 is a cross-sectional view taken along line I-I' in Figure 3 according to an embodiment of the present disclosure.

[0021] Figure 5 is a cross-sectional view taken along line II-II' in Figure 3 according to an embodiment of the present disclosure.

[0022] Figure 6 is a cross-sectional view taken along line III-III' in Figure 3 according to an embodiment of the present disclosure.

[0023] Figure 7 is a cross-sectional view showing an example in which a main light-emitting element and a sub-light-emitting element are electrically connected to a pixel driving circuit according to an embodiment of the present disclosure.

[0024] Figure 8 is a diagram showing a display device according to an embodiment of the present disclosure.

[0025] Figure 9 is a cross-sectional view taken along line IV-IV' in Figure 8 according to an embodiment of the present disclosure.

[0026] Figure 10 is a diagram showing a partial region of a pixel according to an embodiment of the present disclosure.

[0027] Figure 11 is a cross-sectional view taken along line Y-Y' in Figure 8 according to an embodiment of the present disclosure.

[0028] Figure 12A and Figure 12B are perspective views showing a manufacturing process of a display device according to an embodiment of the present disclosure.

[0029] Figures 13A to 13E is a cross-sectional view of the manufacturing process of a display device according to an embodiment of the present disclosure in the Figure 8 Z-Z' direction. DETAILED DESCRIPTION

[0030] The advantages and features of the present disclosure and the methods for realizing them will be apparent from the embodiments described in detail below in conjunction with the accompanying drawings. However, the present disclosure is not limited to the following embodiments, but can be implemented in various different forms. On the contrary, the present embodiments will enable those skilled in the art to fully understand the scope of the present disclosure.

[0031] The shapes, sizes, ratios, angles, quantities, etc. shown in the accompanying drawings for describing the embodiments of the present disclosure are only examples, and the present disclosure is not limited thereto. Throughout the specification, the same reference numerals generally denote the same elements. In addition, when describing the present disclosure, detailed descriptions of known related technologies may be omitted so as not to unnecessarily obscure the subject matter of the present disclosure.

[0032] The terms "comprising", "including" and "having" used herein generally intend to allow the addition of other components, unless these terms are used together with "only". Unless otherwise explicitly stated, the mention of the singular shall be construed as including the plural.

[0033] When interpreting components, even if not explicitly stated, they will be construed as including a margin of error.

[0034] When describing the positional or interconnection relationship between two components, such as "on top of", "above", "below", "next to", "connected or coupled to", "crossing", "intersecting", etc., unless "immediately" or "directly" is used, one or more other components may be interposed between them.

[0035] When describing the context relationship of time, such as "after", "subsequently", "then" or "before", unless "immediately" or "directly" is used, it may be discontinuous on the time scale.

[0036] First, second, etc. may be used in front of component names to distinguish components, but their functions or structures are not limited by such ordinal numbers or component names. For the sake of convenience in description, the ordinal numbers in front of the same component names may be different in the embodiments.

[0037] The following embodiments may be combined or associated with each other in whole or in part, and various types of interactions and drives can be achieved technically. Each embodiment may be implemented independently of each other or implemented in association with each other.

[0038] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0039] A display device according to an embodiment of the present disclosure includes: a display panel having a display area or screen for displaying an image; and a pixel driving circuit for driving the pixels of the display panel. The display area includes a pixel area provided with pixels. The pixel area includes a plurality of light-emitting areas. A light-emitting element is provided in each light-emitting area. The pixel driving circuit may be embedded in the display panel.

[0040] Figure 1 FIG. is a view showing a display device according to an embodiment of the present disclosure. Figure 2 is according to an embodiment of the present disclosure Figure 1 An enlarged view of region A. Figure 3 FIG. is a view showing a partial region of a pixel according to an embodiment of the present disclosure.

[0041] Referring to Figure 1 and Figure 2 FIGS. and, a display device 100 according to an embodiment of the present disclosure includes a display panel that visually reproduces an input image. The display panel may include a display area AA for displaying an image and a non-display area NA for not displaying an image. In the non-display area NA, various wirings and driving circuits may be installed, and a pad portion PAD connected to an integrated circuit, a printed circuit, etc. may be provided. Here, the display panel may have a rectangular structure having a width in the X-axis direction, a length in the Y-axis direction, and a thickness in the Z-axis direction. In this case, the width and length of the display panel may be set to various design values according to the application field of the display device. The X-axis direction may refer to the width direction, the row direction, or the horizontal direction, the Y-axis direction may refer to the length direction, the column direction, or the vertical direction, and the Z-axis direction may refer to the up-down direction or the thickness direction. In addition, the X-axis direction, the Y-axis direction, and the Z-axis direction may be perpendicular to each other, but may also refer to different directions that are not perpendicular to each other. Therefore, the X-axis direction, the Y-axis direction, and the Z-axis direction may each be described as one of the first direction, the second direction, and the third direction. A plane extending in the X-axis direction and the Y-axis direction may refer to a horizontal plane.

[0042] The plurality of light-emitting elements 10 provided in the display area AA to form the pixel PXL may be micro inorganic light-emitting elements or micro light-emitting diodes (micro LEDs). The inorganic light-emitting element may be grown on a silicon wafer and then attached to the display panel through a transfer process.

[0043] The transfer process of the light-emitting element 10 may be performed for each pre-divided region. In Figure 1 FIG., the display area AA is shown divided into 12 transfer regions ST, but the size or the number of divisions of the transfer region is not limited thereto. The transfer process may be performed on the first transfer region ST to the twelfth transfer region ST sequentially or simultaneously. The plurality of light-emitting elements 10 may include blue light-emitting elements 10, green light-emitting elements 10, and red light-emitting elements 10, and the blue light-emitting elements 10, the green light-emitting elements 10, and the red light-emitting elements 10 may be transferred to the transfer region ST in sequence.

[0044] In the non-display area NA, a data driving circuit or a gate driving circuit may be provided, and wirings may be provided for applying control signals for controlling the driving circuits. Here, the control signals may include various timing signals (including a clock signal, an input data enable signal, and a synchronization signal), and may be received through the pad portion PAD.

[0045] The pixel PXL may be driven by a pixel driving circuit. The pixel driving circuit may receive a driving voltage, an image signal (digital signal), a synchronization signal synchronized with the image signal, etc., and output an anode voltage and a cathode voltage of the light-emitting element 10 to drive a plurality of pixels. The driving voltage may be a high-potential voltage EVDD. The cathode voltage may be a low-potential voltage EVSS commonly applied to the pixels. The anode voltage may be a voltage corresponding to the pixel data value of the image signal. The pixel driving circuit may be provided in the non-display area NA, or may be provided under the display area AA.

[0046] Each pixel PXL may include a plurality of sub-pixels having different colors. For example, the plurality of sub-pixels may include: a red sub-pixel provided with a light-emitting element 10 that emits light having a red wavelength; a green sub-pixel provided with a light-emitting element 10 that emits light having a green wavelength; and a blue sub-pixel provided with a light-emitting element 10 that emits light having a blue wavelength. The plurality of sub-pixels may further include a white sub-pixel.

[0047] Refer to Figure 2 and Figure 3 , a plurality of pixels PXL may be continuously arranged in a first direction (X-axis direction) and a second direction (Y-axis direction). A plurality of sub-pixels of the same color may be provided within the pixels of the display area AA. For example, each of the plurality of pixels may include: a first red sub-pixel provided with a first-first light-emitting element 11a that emits light having a red wavelength; a second red sub-pixel provided with a first-second light-emitting element 11b that emits light having a red wavelength; a first green sub-pixel provided with a second-first light-emitting element 12a that emits light having a green wavelength; a second green sub-pixel provided with a second-second light-emitting element 12b that emits light having a green wavelength; a first blue sub-pixel provided with a third-first light-emitting element 13a that emits light having a blue wavelength; and a second blue sub-pixel provided with a third-second light-emitting element 13b that emits light having a blue wavelength. The first-first light-emitting element 11a, the first-second light-emitting element 12a, and the first-third light-emitting element 13a may be regarded as main light-emitting elements. The first-second light-emitting element 11b, the second-second light-emitting element 12b, and the third-second light-emitting element 13b may be regarded as sub-light-emitting elements.

[0048] A sub-pixel may include one or more light-emitting elements, and in the case where one light-emitting element becomes defective, the brightness of another light-emitting element may be increased to adjust the brightness of the sub-pixel. However, the present disclosure is not necessarily limited thereto, and a sub-pixel may include only one light-emitting element.

[0049] A plurality of first electrodes 161 may be respectively disposed under the light-emitting elements 10, and may be selectively connected to a plurality of signal lines TL (TL1 to TL6) through the extension portions 161a. A high-potential voltage may be applied to the pixel driving circuit through the signal lines TL1 to TL6. In the electrode patterning process, the signal lines TL1 to TL6 and the first electrodes 161 may be formed as an integrated electrode pattern.

[0050] For example, the first signal line TL1 may be connected to the anode of the first red sub-pixel, and the second signal line TL2 may be connected to the anode of the second red sub-pixel. The third signal line TL3 may be connected to the anode of the first green sub-pixel, and the fourth signal line TL4 may be connected to the anode of the second green sub-pixel. The fifth signal line TL5 may be connected to the anode of the first blue sub-pixel, and the sixth signal line TL6 may be connected to the anode of the second blue sub-pixel. When a sub-pixel includes only one light-emitting element, the number of the signal lines TL may be reduced by half.

[0051] The second electrode 170 may be a cathode disposed in each row, and applies a cathode voltage to the light-emitting elements 10 continuously arranged in the first direction (X-axis direction). A plurality of second electrodes 170 may be spaced apart from each other in the second direction (Y-axis direction). A plurality of second electrodes 170 may be connected to the cathode voltage through the contact electrodes 163. Each of the plurality of second electrodes 170 may be electrically connected to the contact electrode 163. However, the present disclosure is not necessarily limited thereto, and the second electrode 170 may be configured as one electrode layer without being divided into a plurality of electrodes, and may be used as a common electrode.

[0052] Figure 4 is a cross-sectional view taken along line I-I' in Figure 3 according to an embodiment of the present disclosure. Figure 5 is a cross-sectional view taken along line II-II' in Figure 3 according to an embodiment of the present disclosure. Figure 6 is a cross-sectional view taken along line III-III' in Figure 3 according to an embodiment of the present disclosure. Figure 7 is a cross-sectional view showing an example in which two light-emitting elements are connected to a pixel driving circuit according to an embodiment of the present disclosure.

[0053] Refer to Figures 3 to 5, The display device according to an embodiment includes a plurality of first electrodes 161 and contact electrodes 163 disposed above a substrate 110, a plurality of light-emitting elements 10 disposed on the plurality of first electrodes 161, a first optical layer 141 disposed between the plurality of light-emitting elements 10, and a second electrode 170 disposed on the plurality of light-emitting elements 10. In some embodiments, the first electrodes are on the top surface 130-2 and the side surface 130-1 of the protrusion of the bank 130 (see Figure 11 ). In some embodiments, the contact electrode 163 is on an insulating layer 122. The substrate 110 may be made of flexible plastic. For example, the substrate 110 may be made into a single-layer or multi-layer substrate, which is selected from but not limited to the following materials: polyimide, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyethersulfone, polyarylate, polysulfone, and cycloolefin copolymer. For example, the substrate 110 may be a ceramic substrate or a glass substrate.

[0054] A pixel driving circuit 20 may be disposed in a display area AA on the substrate 110. The pixel driving circuit 20 may include a plurality of thin film transistors using amorphous silicon semiconductors, polysilicon semiconductors, or oxide semiconductors.

[0055] The pixel driving circuit 20 may include at least one driving thin film transistor, at least one switching thin film transistor, and at least one storage capacitor. When the pixel driving circuit 20 includes a plurality of thin film transistors, it may be formed on the substrate 110 by a thin film transistor (TFT) manufacturing process. In one embodiment, the pixel driving circuit 20 may be a general term for a plurality of thin film transistors electrically connected to the light-emitting elements 10.

[0056] The pixel driving circuit 20 may be a driver manufactured using a metal-oxide-silicon field effect transistor (MOSFET) manufacturing process on a single crystal semiconductor substrate 110. The driver may include a plurality of pixel driving circuits to drive a plurality of sub-pixels. When the pixel driving circuit 20 is implemented as a driving driver, an adhesive layer may be disposed on the substrate 110, and then the driving driver may be mounted on the adhesive layer through a transfer process.

[0057] A buffer layer 121 covering the pixel driving circuit 20 may be disposed on the substrate 110. The buffer layer 121 may be made of an organic insulating material (e.g., photosensitive acrylic resin or photosensitive polyimide), but is not limited thereto.

[0058] The buffer layer 121 may be formed by laminating a plurality of layers of inorganic insulating materials (e.g., silicon nitride (SiN x )) or silicon dioxide (SiO 2 ), or the buffer layer 121 may be formed by laminating a plurality of layers of organic insulating materials and inorganic insulating materials.

[0059] The insulating layer 122 may be disposed on the buffer layer 121. The insulating layer 122 may be made of an organic insulating material (e.g., photosensitive acrylic resin or photosensitive polyimide), but is not limited thereto. Connection lines may be disposed on the buffer layer 121. The connection lines may include a plurality of connection lines, e.g., a first connection line RT1 and a second connection line RT2. The connection lines may be connected to corresponding signal lines TL. The signal lines may include a first signal line TL1 to a sixth signal line TL6, but are not limited thereto. The connection lines may include a plurality of line patterns in different layers with one or more insulating layers interposed therebetween. The line patterns in different layers may be electrically connected through contact holes penetrating the insulating layers.

[0060] A plurality of bank patterns (which may also be referred to as banks herein) 130 may be disposed on the insulating layer 122. At least one light-emitting element 10 may be disposed on each bank pattern 130. For example, a first light-emitting element 11 may be disposed on a first bank pattern 130a, a second light-emitting element 12 may be disposed on a second bank pattern 130b, and a third light-emitting element 13 may be disposed on a third bank pattern 130c. In some embodiments, the bank 130 includes a plurality of protrusions. In some embodiments, at least one light-emitting element 10 is disposed on each protrusion of the bank 130. For example, the first light-emitting element 11 may be disposed on a first protrusion of the bank 130, the second light-emitting element 12 may be disposed on a second protrusion of the bank 130, and the third light-emitting element 13 may be disposed on a third protrusion of the bank 130.

[0061] The bank pattern 130 may be made of an organic insulating material (e.g., photosensitive acrylic resin or photosensitive polyimide), but is not limited thereto. The bank pattern 130 and / or the protrusions of the bank 130 may guide the position where the light-emitting element 10 is to be attached during the transfer process of the light-emitting element 10. In some embodiments, the bank pattern 130 may be omitted.

[0062] A solder pattern 162 may be disposed on the first electrode 161. The solder pattern 162 may be made of indium (In), tin (Sn), gold (Au), or an alloy of the foregoing metals, but is not limited thereto. The solder pattern 162 may be formed by eutectic bonding of at least two metals selected from indium (In), tin (Sn), and gold (Au).

[0063] A plurality of light-emitting elements 10 may be respectively mounted on the solder pattern 162. One pixel may include light-emitting elements 10 of three colors. The first light-emitting element 11 may be a red light-emitting element, the second light-emitting element 12 may be a green light-emitting element, and the third light-emitting element 13 may be a blue light-emitting element. Two light-emitting elements may be mounted in each sub-pixel.

[0064] The first optical layer 141 may cover the plurality of light-emitting elements 10 and the plurality of bank patterns 130. Accordingly, the first optical layer 141 may cover between the plurality of light-emitting elements 10 and between the plurality of bank patterns 130. The first optical layer 141 may extend in a first direction X and be separately disposed in a second direction Y to separate pixels disposed at intervals from each other in the second direction Y. Accordingly, the first optical layer 141 may be separated between pixel rows. Here, a row may represent the first direction. In addition, a single pixel row formed of a plurality of pixels arranged in the first direction may be referred to as a pixel group. Accordingly, the display panel may include a plurality of pixel groups disposed at intervals from each other in the second direction. For example, since the first optical layer 141 disposed in the first direction is disposed around the pixels, and the plurality of first optical layers 141 corresponding to the plurality of pixel groups are disposed at intervals from each other in the second direction, one first optical layer 141 disposed around the pixels forming a single row may be separated from another first optical layer 141 disposed around the pixels forming another row.

[0065] The first optical layer 141 may include an organic insulating material in which fine metal particles (e.g., titanium dioxide particles) are dispersed. Light emitted from the plurality of light-emitting elements 10 may be scattered by the fine metal particles dispersed in the first optical layer 141 and emitted to the outside.

[0066] The second electrode 170 may be disposed on the plurality of light-emitting elements 10. The second electrode 170 may be commonly connected to the plurality of pixels PXL. The second electrode 170 may be a transmissive thin electrode. The second electrode 170 may be made of a transparent electrode material (e.g., indium tin oxide (ITO)), but is not necessarily limited thereto.

[0067] In some embodiments, the second electrode 170 is located on the light-emitting element 10 of each of the plurality of sub-pixels 11, 12, 13. The second electrode 170 may extend in a first direction (X-axis direction) and may be spaced apart in a second direction (Y-axis direction). For example, a single second electrode 170 may be formed to extend in the first direction, and the plurality of second electrodes 170 extending in the first direction may be arranged to be spaced apart from each other in the second direction. In this case, the second electrode 170 may be disposed to correspond to the respective pixels spaced apart from each other in the second direction.

[0068] The second electrode 170 may include: a first region 171 disposed on the top surface of the light-emitting element 10 and the top surface of the first optical layer 141; a second region 172 in contact with the contact electrode 163 and electrically connected to the contact electrode 163; and a third region 173 disposed on the side surface of the first optical layer 141 and connecting the first region 171 and the second region 172.

[0069] In a plane, each of the plurality of second electrodes 170 may overlap with the first optical layer 141, and the third region 173 may cover the outer surface of the first optical layer 141.

[0070] In some embodiments, the display device further includes a second optical layer 142. The first optical layer 141 surrounds the light-emitting element 10, and the second optical layer 142 is disposed on the first optical layer 141. The second optical layer 142 may be an organic insulating material surrounding the periphery of the first optical layer 141. The second optical layer 142 may be disposed on the insulating layer 122 together with the first optical layer 141. The first optical layer 141 and the second optical layer 142 may include the same material (e.g., silicone), but in some embodiments, the first optical layer 141 may include reflective particles, while the second optical layer 142 may not include reflective particles. For example, the first optical layer 141 may be a silicone containing titanium oxide (TiO x ), and the second optical layer 142 may be a silicone without titanium oxide (TiO x ). However, the present disclosure is not necessarily limited thereto, and the first optical layer 141 and the second optical layer 142 may be formed of the same material or different materials.

[0071] According to an embodiment, the second region 172 of the second electrode 170 is connected to the contact electrode while being integrally formed flat, so that excessive stress is not concentrated at the connection point with the contact electrode 163. Therefore, cracks generated in the second electrode 170 can be effectively prevented or at least reduced.

[0072] The second optical layer 142 may cover the second region 172 and the third region 173 of the second electrode 170. The top surface of the second optical layer 142 and the top surface of the first region 171 of the second electrode 170 may be formed in the same plane. That is, the first region 171 and the second optical layer 142 may be used as a planarization layer.

[0073] Therefore, since there is no height difference on the surface on which the black matrix 190 is formed, the pattern of the black matrix 190 can be easily formed on the first optical layer 141 and the second optical layer 142. However, the present disclosure is not necessarily limited thereto, and the top surface of the second optical layer 142 and the top surface of the second electrode 170 may have different heights.

[0074] In some embodiments, the black matrix 190 covers at least one of the plurality of light-emitting elements 10. In some embodiments, a sub-pixel (e.g., a first sub-pixel or a second sub-pixel) includes a first light-emitting element (a first-first light-emitting element 11a, a second-first light-emitting element 12a, and a third-first light-emitting element 13a) and a second light-emitting element (a first-second light-emitting element 11b, a second-second light-emitting element 12b, and a third-second light-emitting element 13b) that emit light of the same color. The black matrix 190 covers one of the first light-emitting element and the second light-emitting element and does not cover the other of the first light-emitting element and the second light-emitting element.

[0075] The black matrix 190 may be an organic insulating material added with a black pigment. The second electrode 170 may be in contact with the contact electrode 163 under the black matrix 190. Transmission holes 191 may be formed between the patterns of the black matrix 190, and light from the light-emitting element 10 is emitted to the outside through the transmission holes 191.

[0076] The transmission holes 191 may overlap with the light-emitting element 10 in the Z-axis direction, and a partial region of the black matrix 190 may overlap with the first optical layer 141 in the Z-axis direction. Here, the Z-axis direction may be referred to as the third direction. Therefore, the black matrix 190 can solve the problem that light emitted from adjacent light-emitting elements 10 is mixed by the first optical layer 141 and then emitted.

[0077] A first-second optical layer (not shown) having the same material as the first optical layer 141 may be additionally provided between the black matrix 190 and the second electrode 170. The first-second optical layer is used to improve the light efficiency of the light emitted to the front surface.

[0078] The cover layer 180 may be an organic insulating material that covers the black matrix 190 and the second electrode 170. In Figure 2 and Figure 3 the structures of the black matrix 190 and the cover layer 180 are omitted.

[0079] The contact electrode 163 may be electrically connected to the first connection line RT1 provided thereunder, and the first connection line RT1 may be connected to the pixel driving circuit 20. Therefore, a cathode voltage can be applied to the second electrode 170 through the contact electrode 163. The first electrode 161 may be electrically connected to the second connection line RT2. This will be described later.

[0080] Referring to Figure 5 , the contact electrode 163 and the signal lines TL1 to TL6 may be provided on the same plane. The pixel driving circuit 20 may be provided under the contact electrode 163 and the signal lines TL1 to TL6. When the pixel driving circuit 20 is a driving driver, a plurality of driving drivers may be provided in the display panel.

[0081] The passivation layer 133 can expose the contact electrode 160, enabling the contact electrode 163 and the second electrode 170 to be electrically connected to each other. Additionally, the passivation layer 133 can insulate the signal lines TL2 to TL5 from the second electrode 170. Here, the passivation layer 133 can be formed of an inorganic material.

[0082] Referring Figure 6 , the extension 161a of the first electrode 161 can extend to a side surface 131 of the embankment pattern 130 to be electrically connected to the connection line RT2 provided on the buffer layer 121.

[0083] The first electrode 161, the extension 161a, the signal line TL, and / or the connection lines RT1 and RT2 can include a single-layer or multi-layer metal layer selected from titanium (Ti), molybdenum (Mo), and aluminum (Al).

[0084] The first electrode 161 or the signal line TL can be formed as a metal layer stack structure having multiple metal layers formed of different materials, thicknesses, etc. In this case, the first electrode 161, the extension 161a, and the signal line TL can be formed simultaneously through the same manufacturing process. Here, the thickness can represent the width between one surface and another surface of the metal layer provided in the Z-axis direction.

[0085] The first electrode 161 can include a first metal layer ML1 provided below the welding pattern 162, a second metal layer ML2 provided below the first metal layer ML1, a third metal layer ML3 provided below the second metal layer ML2, and a fourth metal layer ML4 provided below the third metal layer ML3. When the first electrode 161 is formed of the first metal layer ML1, the second metal layer ML2, the third metal layer ML3, and the fourth metal layer ML4, the first electrode 161 can be deposited in the order of the fourth metal layer ML4, the third metal layer ML3, the second metal layer ML2, and the first metal layer ML1, and then the first electrode 161 can be patterned by performing a photolithography process and an etching process.

[0086] The first metal layer ML1 can be provided in contact with the lower part of the welding pattern 162 and can be electrically connected to the welding pattern 162.

[0087] Additionally, the first metal layer ML1 can include a transparent conductive oxide layer having good adhesion, corrosion resistance, and acid resistance, such as indium tin oxide (ITO) and / or indium zinc oxide (IZO). Here, the first metal layer ML1 can be referred to as an adhesion layer.

[0088] The second metal layer ML2 may be formed of a material having a resistivity value different from that of the first metal layer ML1 and the third metal layer ML3. In this case, the second metal layer ML2 may be formed of a material having a lower light reflectivity than the third metal layer ML3 but a higher resistance value. For example, the second metal layer ML2 may include titanium (Ti) and / or molybdenum (Mo).

[0089] The third metal layer ML3 may be formed of a material having a higher light reflectivity than the first metal layer ML1. In this case, the third metal layer ML3 may be formed of a material having a higher light reflectivity than the second metal layer ML2. For example, the third metal layer ML3 may include aluminum (Al) and / or silver (Ag).

[0090] That is, the light reflectivity of the third metal layer ML3 may be greater than the light reflectivities of the first metal layer ML1 and the second metal layer ML2.

[0091] The fourth metal layer ML4 may be formed of the same material as the second metal layer ML2. For example, the fourth metal layer ML4 may include titanium (Ti) and / or molybdenum (Mo).

[0092] After the first metal layer ML1 is formed, a reflection opening OP may be formed in the first electrode 161. The reflection opening OP may be an area where the first metal layer ML1 and the second metal layer ML2 are removed and only a part of the third metal layer ML3 is exposed. In a plane, the reflection opening OP may have a shape surrounding the welding pattern 162 and may be circular or quadrilateral, but is not limited thereto.

[0093] Light emitted from the light-emitting element 10 may be reflected from the surface of the third metal layer ML3 (i.e., the reflection layer 161b) exposed through the reflection opening OP, thereby improving the light efficiency of the display device.

[0094] In some embodiments, the first electrode 161 includes a reflection layer. In some embodiments, the first electrode 161 includes a reflective metal layer (e.g., the third metal layer ML3) and a non-reflective metal layer (e.g., the first metal layer ML1 and / or the second metal layer ML2) on the reflective metal layer. A part of the reflective metal layer is exposed through an opening (e.g., the opening OP) in the non-reflective metal layer to form the reflective metal layer. In some embodiments, the non-reflective metal layer extends to the top surface of the bank 130, and a part of the reflective metal layer exposed through the opening in the non-reflective metal layer is on the top surface of the bank 130. In some embodiments, the optical layer 141 is located between the reflection layer and the light-emitting element 10.

[0095] The passivation layer 133 may include an opening hole 133a that is disposed on the first electrode 161 and the signal line TL and exposes the welding pattern 162. Here, the opening hole 133a that exposes the welding pattern 162 may be referred to as a first opening hole. In this case, the reflection opening OP may be formed to surround the first opening hole.

[0096] The light-emitting element 10 may include a first-conductive-type semiconductor layer 10-1, an active layer 10-2 disposed on the first-conductive-type semiconductor layer 10-1, and a second-conductive-type semiconductor layer 10-3 disposed on the active layer 10-2. The first driving electrode 15 may be disposed under the first-conductive-type semiconductor layer 10-1, and the second driving electrode 14 may be disposed above the second-conductive-type semiconductor layer 10-3.

[0097] The light-emitting element 10 may be formed on a silicon wafer by a method such as metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), molecular beam epitaxy (MBE), hydride vapor phase epitaxy (HVPE), or sputtering.

[0098] The first-conductive-type semiconductor layer 10-1 may be implemented with a compound semiconductor such as a group III-V or II-VI compound, and may be doped with a first dopant. The first-conductive-type semiconductor layer 10-1 may be formed of one or more of semiconductor materials having the formula Al x1 In y1 Ga (1-x1-y1) N (0≤x1≤1, 0≤y1≤1, 0≤x1 + y1≤1), InAlGaN, AlGaAs, GaP, GaAs, GaInP, and AlGaInP, but is not limited thereto. When the first dopant is an n-type dopant such as Si, Ge, Sn, Se, or Te, the first-conductive-type semiconductor layer 10-1 may be an n-type nitride semiconductor layer. However, when the first dopant is a p-type dopant, the first-conductive-type semiconductor layer 10-1 may be a p-type nitride semiconductor layer.

[0099] The active layer 10-2 is a layer in which electrons (or holes) injected through the first-conductive-type semiconductor layer 10-1 and holes (or electrons) injected through the second-conductive-type semiconductor layer 10-3 are recombined. The active layer 10-2 transitions to a lower energy level as electrons and holes recombine, and may generate light having a wavelength corresponding thereto.

[0100] The active layer 10-2 may have any one of a single well structure, a multi-well structure, a single quantum well structure, a multi-quantum well (MQW) structure, a quantum dot structure, and a quantum wire structure, but the structure of the active layer 10-2 is not limited thereto. The active layer 10-2 may generate light in the visible wavelength band. For example, the active layer 10-2 may output light of any one of the blue, green, and red wavelength bands.

[0101] The second conductivity type semiconductor layer 10-3 may be disposed on the active layer 10-2. The second conductivity type semiconductor layer 10-3 may be implemented with a compound semiconductor such as a group III-V or II-VI compound semiconductor and may be doped with a second dopant. The second conductivity type semiconductor layer 10-3 may be formed of a semiconductor material having the formula In x2 Al y2 Ga 1-x2-y2 N (0≤x2≤1, 0≤y2≤1, 0≤x2 + y2≤1) or a material selected from AlInN, AlGaAs, GaP, GaAs, GaAsP, AlGaInP, and AlGaInP. When the second dopant is a p-type dopant such as Mg, Zn, Ca, Sr, Ba, etc., the second conductivity type semiconductor layer 10-3 doped with the second dopant may be a p-type nitride semiconductor layer. When the second dopant is an n-type dopant, the second conductivity type semiconductor layer 10-3 may be an n-type nitride semiconductor layer.

[0102] In one embodiment, although the driving electrodes 14 and 15 are described as being disposed above and below the light emitting structure in a vertical structure, in addition to the vertical structure, the light emitting element may have a lateral structure or a flip chip structure.

[0103] Referring to Figure 7 , the main light emitting element 12a and the sub-light emitting element 12b of the sub-pixel may be disposed on the bank pattern 130. The second light emitting element 12 is exemplarily described. The first-first electrode 161-1 connected to the main light emitting element 12a may extend to one side surface of the bank pattern 130 to be electrically connected to the second-first connection line RT21 disposed therebelow. The first-second electrode 161-2 connected to the sub-light emitting element 12b may extend to the other side surface of the bank pattern 130 to be electrically connected to the second-second connection line RT22 disposed therebelow.

[0104] The pixel driving circuit 20 may apply an anode voltage to the main light emitting element 12a through the second-first connection line RT21 and may apply an anode voltage to the sub-light emitting element 12b through the second-second connection line RT22. The pixel driving circuit 20 may apply a cathode voltage to the main light emitting element 12a and the sub-light emitting element 12b through the first connection line RT1 and the second electrode 170.

[0105] The pixel driving circuit 20 can adjust the brightness by driving only the main light-emitting element 12a, or can adjust the brightness by driving both the main light-emitting element 12a and the sub light-emitting element 12b simultaneously. When the main light-emitting element 12a becomes a dark spot, the brightness can be adjusted by driving only the sub light-emitting element 12b.

[0106] Figure 8 FIG. is a diagram showing a display device according to an embodiment of the present disclosure. Figure 9 is according to an embodiment of the present disclosure along Figure 8 The cross-sectional view taken along line IV-IV' in.

[0107] Referring to Figure 8 and Figure 9 The second electrode 170 can be electrically connected to the contact electrode 163 through the contact hole TH1 formed in the second optical layer 142. The second optical layer 142 may include a contact hole TH1 exposing the contact electrode 163. The second electrode 170 inserted into the contact hole TH1 of the second optical layer 142 may be in contact with the top surface of the contact electrode 163. The contact hole TH1 may be formed in the outer region of the pixel. In some embodiments, the contact electrode 163 is on an insulating layer 122. The contact hole TH1 penetrates through the first optical layer 141 and the second optical layer 142. The second electrode 170 contacts the contact electrode 161 through the contact hole TH1.

[0108] Figure 10 FIG. is a diagram showing a partial region of a pixel according to another embodiment of the present disclosure. Hereinafter, the parts different from Figure 2 and Figure 3 will be mainly described.

[0109] A plurality of first electrodes 161 may be respectively disposed under the light-emitting elements 10, and may be selectively connected to the plurality of signal lines TL1 to TL6 through the extension portions 161a. The extension portion 161a may be less than or equal to the length of one surface of the first electrode 161. A high-potential voltage may be applied to the pixel driving circuit through the signal lines TL to TL6. The signal lines TL to TL6 and the first electrode 161 may be formed as an integrated electrode pattern during the electrode patterning process.

[0110] For example, the first signal line TL1 may be connected to the anode of the first red sub-pixel, and the second signal line TL2 may be connected to the anode of the second red sub-pixel. The third signal line TL3 may be connected to the anode of the first green sub-pixel, and the fourth signal line TL4 may be connected to the anode of the second green sub-pixel. The fifth signal line TL5 may be connected to the anode of the first blue sub-pixel, and the sixth signal line TL6 may be connected to the anode of the second blue sub-pixel. When one sub-pixel includes only one light-emitting element, the number of the signal lines TL may be reduced by half.

[0111] The second electrode 170 may be a cathode that is provided in each row and applies a cathode voltage to the light-emitting elements 10 arranged continuously in the first direction (X-axis direction). The plurality of second electrodes 170 may be spaced apart from each other in the second direction (Y-axis direction). The plurality of second electrodes 170 may be connected to the cathode voltage through the contact electrodes 163. Each of the plurality of second electrodes 170 may be electrically connected to the contact electrode 163. However, the present disclosure is not necessarily limited thereto, and the second electrode 170 may be configured as one electrode layer without being divided into a plurality of electrodes and may be used as a common electrode.

[0112] A reflective layer 161b is provided on the first electrode 161. The reflective layer 161b may have a shape surrounding the region where the first electrode 161 contacts the welding pattern 162. The reflective layer 161b may be formed by depositing a reflective material on the first electrode 161. When the first electrode 161 is composed of a plurality of metal layers (including a reflective metal layer located below and a non-reflective metal layer located thereon), the reflective layer 161b may be formed by removing the non-reflective metal layer and exposing the reflective metal layer. In particular, in the first electrode 161, the exposed surface of the reflective metal layer ML3 may be used as the reflective layer 161b. In this case, the reflective layer 161b may be formed in the same manner as the reflective opening OP shown in an embodiment of Figure 6 but is not limited thereto.

[0113] Figure 11 is a cross-sectional view taken along the line Y-Y' in Figure 8 and Figure 12A and Figure 12B are perspective views of a manufacturing process of a display device according to an embodiment of the present disclosure.

[0114] Figure 11 , Figure 12A and Figure 12B only show the components corresponding to the bank pattern 130, the first electrode 161, the light-emitting element 10, the reflective layer 161b, the first optical layer 141, the welding pattern 162, and the recess CON, and the configurations of the other components are the same as those of the components in Figure 6 . In some embodiments, the bank 130 includes a plurality of protrusions. At least one of the plurality of protrusions includes a recess CON. The first electrode 161 is provided in the recess CON, the light-emitting element is provided on the first electrode 161 and at least partially located in the recess, and the second electrode 170 is provided on the light-emitting element 10.

[0115] Referring to Figure 11 , Figure 12A and Figure 12B, a recess CON is formed in the bank pattern 130. The center of the recess CON may coincide with the center of the bank pattern 130, but the present disclosure is not limited thereto. The top CON-3 and the bottom surface CON-1 of the recess CON may be circular, quadrilateral, or a shape in which only the corner portions of the edges are rounded, but is not limited thereto. The depth of the recess CON may be defined as the vertical distance between the top CON-3 and the bottom surface CON-1 of the recess CON. In other words, the depth of the recess CON may be defined as the vertical height of the side surface CON-2 of the recess CON.

[0116] The depth of the recess CON may be less than the height of the light-emitting element 10 such that the light-emitting element 10 is partially disposed in the recess CON. The top surface of the light-emitting element 10 is farther from the substrate 110 than the bottom surface of the light-emitting element 10. In some embodiments, the area of the bottom surface CON-1 of the recess CON is larger than the area of the opening of the top CON-3 of the recess CON. The area of the bottom surface CON-1 of the recess CON and the area of the opening of the top CON-3 of the recess CON are larger than the area of the lower surface of the light-emitting element 10. In some embodiments, the area of the bottom surface CON-1 of the recess CON is 1.2 to 1.5 times the area of the lower surface of the light-emitting element 10.

[0117] This is to prevent or at least reduce the incorrect transfer or misalignment of the light-emitting element 10 to the inner surface CON-2 of the recess CON or the top surface 130-2 of the bank pattern 130 due to transfer errors when transferring the light-emitting element 10 to the bottom surface CON-1 of the recess CON. Additionally, as will be described later, this is to prevent or at least reduce the problem that the light-emitting element 10 and the first optical layer are removed together during the process of removing and re-coating the first optical layer due to defects found therein after the first optical layer is initially coated.

[0118] Since the active layers 10-2 of the light-emitting elements 10 for various colors have different light efficiencies, the sizes of the light-emitting elements 10 for various colors may be different. Therefore, the areas of the top and bottom surfaces of the recess CON may also be different according to the color of the light emitted by the light-emitting element 10. The area of the top surface of the light-emitting element 10 may be larger than the area of its bottom surface. For example, when the light-emitting element 10 is rectangular, i.e., the length of each side of the upper surface of the light-emitting element 10 may be longer than the corresponding side of the bottom surface of the light-emitting element 10.

[0119] In some embodiments, the light-emitting element is a micro light-emitting diode (micro LED), and the size of the light-emitting element that emits light of a first color is different from the size of the light-emitting element that emits light of a second color. In some embodiments, the size of the first recess in which the light-emitting element that emits light of the first color of the bank pattern is disposed is different from the size of the second recess in which the light-emitting element that emits light of the second color of the bank pattern is disposed.

[0120] Figures 13A to 13E is a cross-sectional view in the Z-Z' direction of the manufacturing process of a display device according to an embodiment of the present disclosure in Figure 8 the Z-Z' direction.

[0121] Refer to Figures 13A to 13E , the manufacturing process of the display device according to an embodiment of the present disclosure is as follows.

[0122] Refer to Figure 13A , a bank pattern 130 is formed on a substrate 110. When forming the bank pattern 130, a halftone mask is used in a photolithography process. By using the halftone mask, a recess CON can be formed on the upper surface 130-2 of the bank pattern 130. The central portion of the recess CON may coincide with the central portion of the bank pattern 130, but is not limited thereto. The top CON-3 and the bottom surface CON-1 of the recess CON may be circular, rectangular, or only the edges are rounded, but are not limited thereto. The depth of the recess CON can be defined as the vertical distance between the top CON-3 of the recess CON and the bottom surface CON-1 of the recess CON.

[0123] The depth of the recess CON can be less than the height of the light-emitting element 10. So that the light-emitting element is partially disposed in the recess CON. In some embodiments, the area of the bottom surface CON-1 of the recess CON is larger than the area of the bottom surface of the light-emitting element. The bottom surface CON-1 and the top CON-3 of the recess CON are larger than the area of the bottom surface of the light-emitting element 10. For example, the area of the bottom surface CON-1 can be 1.2 times to 1.5 times the area of the bottom surface of the light-emitting element 10.

[0124] Refer to Figure 13B, the first electrode 161 is formed to cover at least a part of the inner surface of the recess CON (i.e., the bottom surface CON-1 and the side surface CON-2) and the top surface 130-2 of the bank pattern 130. Subsequently, a reflective metal such as aluminum is deposited in the reflective layer 161b. In addition, the first electrode may be formed to extend above the upper surface 130-2 and the side surface 130-1 of the bank pattern 130. In this case, the first electrode 161 may be formed by sequentially depositing a plurality of metal layers (e.g., the fourth metal layer ML4, the third metal layer ML3, the second metal layer ML2, and the first metal layer ML1). In this case, the third metal layer ML3 may be deposited with a reflective metal (e.g., aluminum). However, the present disclosure is not limited thereto.

[0125] In some embodiments, the reflective layer 161 is on the bottom surface CON-2 and the side surface CON-2 of the recess CON. In some embodiments, the reflective layer 161b surrounds the portion where the first electrode 161 and the light-emitting element 10 are in contact with each other.

[0126] Subsequently, referring to Figure 13B , among the plurality of metal layers constituting the first electrode 161, for example, the first metal layer ML1 and the second metal layer ML2, which are non-reflective metal layers on the upper surface of the first electrode 161, are removed to expose the surface of the third metal layer ML3, which is a reflective metal layer, to form the reflective layer 161b. In some embodiments, the reflective layer 161b is a part of the first electrode. In some embodiments, the first electrode 161 includes a reflective metal layer ML3 and non-reflective metal layers ML1 and / or ML2. A part of the reflective layer 161 is exposed through an opening in the non-reflective metal layer ML1 and / or ML2 to form the reflective layer 161b. In some embodiments, the non-reflective metal layer ML1 and / or ML2 extends on the top surface of the bank 130, and a part of the reflective metal layer exposed through the opening in the non-reflective metal layer ML1 and / or ML2 is on the top surface 130-2 of the bank 130.

[0127] In some embodiments, the reflective layer 161b may include the entire exposed surface of the third metal layer ML3 of the first electrode 17. In some embodiments, the reflective layer 161 may constitute the inner surface of the recess CON except for the portion where the first electrode 161 contacts the bottom surface of the light-emitting element 10. That is, the exposed surface area of the reflective layer 161b as the third metal layer ML3 may constitute the entire side surface CON-2 and a part of the bottom surface CON-1 of the recess CON. However, the reflective layer 161b may not include the portion where the first metal layer ML1 of the first electrode 161 on the bottom surface CON-1 of the recess CON contacts the bottom surface of the light-emitting element 10 when the light-emitting element 10 is transferred onto the recess CON. In some embodiments, the welding pattern 162 may be formed between the light-emitting element 10 and the first electrode 161.

[0128] As another example, a reflective metal layer may be deposited on the first electrode 161 to form a reflective layer.

[0129] Then, referring to Figure 13C , a passivation layer 133 may be formed on the entire surface of the bank pattern 130 including the first electrode and the reflective layer 161b. Then, the passivation layer 133 may be selectively patterned to form an opening hole 133a that exposes a portion of the first electrode 161 in contact with the light-emitting element 10. In this case, a portion of the upper surface of the first electrode 161 located at the center of the bottom surface CON-1 of the recess CON may be exposed by the opening 133a.

[0130] Then, referring to Figure 13D , the light-emitting element 10 may be transferred to the exposed portion of the first electrode 161 located at the bottom surface CON-1 of the recess CON and electrically connected to the first electrode 161.

[0131] Referring to Figure 13E , a first optical layer 141a is coated to surround the entire light-emitting element 10. In this case, the first optical layer 141a may be disposed on the bank pattern 130 and the side surface of the light-emitting element 10. In some embodiments, the optical layer 141 is located between the reflective layer 161b and the light-emitting element 10 in the recess CON. In addition, a portion 141a of the first optical layer 141 may also be filled in the space between the side surface of the light-emitting element 10 and the reflective layer 161b in the recess CON. In this case, a portion 141a of the first optical layer 141 can not only serve to support the light-emitting element 10 without being separated from the recess CON, but also serve to improve the light reflection efficiency. In this case, due to process problems, there may be a situation where the optical layer does not cover the light-emitting element 10 and the surface of the light-emitting element 10 is exposed. Therefore, during the process of removing the first optical layer using a chemical solution and removing the remaining chemical solution or foreign matter using DI water and an air knife, there may be a problem of loss of the exposed light-emitting element 10. For this reason, when a defect appears in the optical layer, it cannot be repaired, and the display panel itself needs to be discarded, resulting in an increase in the production cost of the product.

[0132] According to an embodiment of the present disclosure, the light-emitting element 10 may be transferred to the bottom surface of the recess CON in the bank pattern 130 such that the recess CON can be used as a water baffle or dam to prevent or at least reduce the loss of the light-emitting element 10 due to water pressure or wind pressure during the above-mentioned process of removing the remaining chemical solution or foreign matter. Therefore, even if a defect appears in the optical layer, the optical layer can be removed and coated again to continue the product production, thereby reducing the cost.

[0133] In one embodiment, a vertical structure in which driving electrodes 14 and 15 are disposed on the top and bottom of a light-emitting structure has been described. However, in addition to the vertical structure, the light-emitting element may have a lateral structure or a flip-chip structure.

[0134] The display device according to an embodiment of the present disclosure may be applied to mobile devices, video phones, smart watches, watch phones, wearable devices, foldable devices, rollable devices, bendable devices, flexible devices, curved devices, sliding devices, variable devices, electronic notepads, e-books, portable multimedia players (PMPs), personal digital assistants (PDAs), MP3 players, mobile medical devices, desktop personal computers (PCs), notebook PCs, netbook computers, workstations, navigation devices, automotive display devices, theater displays, televisions (TVs), wallpaper devices, signage devices, laptop computers, displays, cameras, camcorders, household appliances, etc. In addition, the display device manufactured by transferring a stamp of a light-emitting element and the method of transferring a light-emitting element using a transfer stamp according to one or more embodiments of the present disclosure may be applied to an organic light-emitting lighting device or an inorganic light-emitting lighting device.

[0135] The display device according to one or more embodiments of the present disclosure may be described as follows.

[0136] The display device according to one or more embodiments of the present disclosure may include: a substrate; a plurality of bank patterns disposed on the substrate; a plurality of recesses respectively formed in the plurality of bank patterns; a first electrode disposed in the recesses; a reflective layer disposed on the first electrode; a light-emitting element disposed on the first electrode in the recesses; and a first optical layer disposed to surround a side surface of the light-emitting element.

[0137] The display device may further include a second optical layer disposed on the light-emitting element and a second electrode disposed between the first optical layer and the second optical layer.

[0138] In a plan view, a shape of a bottom surface of the recess may be one of a quadrilateral, a circle, and a quadrilateral having four rounded corners.

[0139] A plurality of light-emitting elements may be disposed in the recesses formed in the plurality of bank patterns arranged adjacent to each other such that: in a first direction, light-emitting elements emitting lights of different colors may be arranged in an order of red, green, and blue, and in a second direction perpendicular to the first direction, light-emitting elements emitting lights of the same color may be arranged, wherein the light-emitting elements emitting lights of different colors may have different sizes.

[0140] The reflective layer may be disposed to surround a contact portion between the light-emitting element and the first electrode.

[0141] The first electrode can be formed by sequentially laminating a reflective metal layer and a non-reflective metal layer, and the reflective layer can be formed by removing the non-reflective metal layer of the first electrode.

[0142] The depth of the recess can be less than the height of the light-emitting element.

[0143] The display device may further include a welding pattern disposed between the light-emitting element and the first electrode, wherein the welding pattern is formed by eutectic bonding of at least two of indium, tin, and gold.

[0144] The display device may further include an insulating layer disposed on the substrate, an adhesive layer disposed on the insulating layer, a pixel driving circuit disposed on the adhesive layer, a buffer layer disposed on the pixel driving circuit, and a plurality of connection lines disposed between the pixel driving circuit and the insulating layer, wherein the pixel driving circuit is connected to the plurality of connection lines, and the plurality of connection lines are electrically connected to the first electrode.

[0145] A method of manufacturing a display device according to one or more embodiments of the present disclosure may include: preparing a substrate; disposing a plurality of bank patterns on the substrate; forming at least one recess in each of the plurality of bank patterns; disposing a first electrode in the recess; forming a reflective layer on the first electrode; forming a light-emitting element on the first electrode in the recess; and disposing a first optical layer around a side surface of the light-emitting element.

[0146] The method may further include disposing a second optical layer on the light-emitting element and disposing a second electrode on the first optical layer.

[0147] In a plan view, the shape of the bottom surface of the recess may be one of a quadrilateral, a circle, and a quadrilateral having four rounded corners.

[0148] The plurality of light-emitting elements disposed in the recesses formed in the plurality of bank patterns arranged adjacent to each other may be arranged such that, in a first direction, light-emitting elements emitting different colors of light may be arranged in the order of red, green, and blue, and in a second direction perpendicular to the first direction, light-emitting elements emitting the same color of light may be arranged, wherein the light-emitting elements emitting different colors of light may have different sizes.

[0149] The reflective layer may be disposed to surround a contact portion of the light-emitting element and the first electrode.

[0150] The first electrode can be formed by sequentially laminating a reflective metal layer and a non-reflective metal layer, and the reflective layer can be formed by removing the non-reflective metal layer of the first electrode.

[0151] The depth of the recess can be less than the height of the light-emitting element.

[0152] The method may further include providing a solder pattern between the light-emitting element and the first electrode, wherein the solder pattern is formed by eutectic bonding of at least two of indium, tin, and gold.

[0153] The method may further include: providing an insulating layer on a substrate; providing an adhesive layer on the insulating layer; providing a pixel driving circuit on the adhesive layer; providing a buffer layer on the pixel driving circuit; and providing a plurality of connection lines between the pixel driving circuit and the insulating layer, wherein the pixel driving circuit is connected to the plurality of connection lines, and the plurality of connection lines are electrically connected to the first electrode.

[0154] A display device according to one or more embodiments of the present disclosure may include: a substrate; a pixel driving circuit on the substrate; one or more insulating layers on the pixel driving circuit; a bank including a plurality of protrusions on the one or more insulating layers. At least one of the plurality of protrusions includes a recess. The display device further includes a pixel. The pixel includes a plurality of sub-pixels. At least one of the plurality of sub-pixels includes: a first electrode in the recess; a light-emitting element disposed on the first electrode and at least partially located in the recess; and a second electrode on the light-emitting element. The area of the bottom surface of the recess is larger than the area of the bottom surface of the light-emitting element.

[0155] In some embodiments, at least one of the plurality of sub-pixels further includes a reflective layer surrounding a portion where the first electrode and the light-emitting element are in contact with each other. In some embodiments, the reflective layer is on the bottom surface and the side surface of the recess. In some embodiments, the reflective layer is a part of the first electrode. In some embodiments, the first electrode includes a reflective metal layer and a non-reflective metal layer on the reflective metal layer. A part of the reflective metal layer is exposed through an opening in the non-reflective metal layer to form the reflective layer. In some embodiments, the non-reflective metal layer extends to the top surface of the bank, and a part of the reflective metal layer exposed by the opening in the non-reflective metal layer is on the top surface of the bank.

[0156] In some embodiments, the display device further includes an optical layer. The optical layer is located between the reflective layer and the light-emitting element in the recess. In some embodiments, the optical layer includes a first optical layer surrounding the light-emitting element of at least one of the plurality of sub-pixels and a second optical layer on the first optical layer. In some embodiments, the first optical layer contains an organic material in which reflective particles are dispersed. In some embodiments, the first optical layer and the second optical layer contain the same organic material. In some embodiments, the first optical layer contains an organic material in which reflective particles are dispersed, and the second optical layer contains an organic material without reflective particles.

[0157] In some embodiments, the display device further includes a black matrix covering at least one of the plurality of sub-pixels. In some embodiments, at least one of the plurality of sub-pixels includes a first light-emitting element and a second light-emitting element that emit light of the same color. In some embodiments, the black matrix covers one of the first light-emitting element and the second light-emitting element and does not cover the other of the first light-emitting element and the second light-emitting element.

[0158] In some embodiments, the light-emitting element is a micro light-emitting diode, and the size of the light-emitting element that emits light of a first color is different from the size of the light-emitting element that emits light of a second color. In some embodiments, the size of the first recess in which the light-emitting element that emits light of a first color is disposed is different from the size of the second recess in which the light-emitting element that emits light of a second color of the bank pattern is disposed.

[0159] In some embodiments, the first electrode is located on the top surface and the side surface of at least one of the plurality of protrusions of the bank. In some embodiments, the second electrode is on the light-emitting element of at least one of the plurality of sub-pixels. In some embodiments, at least one of the plurality of sub-pixels includes a first light-emitting element and a second light-emitting element that emit the same light.

[0160] The effects of the present disclosure are not limited to the effects mentioned above. Those skilled in the art can clearly understand other effects not mentioned through the description of the claims.

[0161] Although the embodiments have been described in detail above with reference to the accompanying drawings, the present disclosure is not necessarily limited to these embodiments, and various changes and modifications can be made without departing from the technical concept of the present disclosure. Therefore, the embodiments disclosed herein should be regarded as descriptive rather than restrictive, and the scope of the technical concept of the present disclosure is not limited by these embodiments. Therefore, the above embodiments should be understood as exemplary and not restrictive in any way.

Claims

1. A display device, comprising: substrate; A pixel driving circuit, on the substrate; One or more insulating layers on the pixel driving circuit; a bank including a plurality of protrusions on the one or more insulating layers, at least one of the plurality of protrusions including a recess, A pixel, comprising a plurality of sub-pixels, at least one of the plurality of sub-pixels comprising: a first electrode in the recess; a light emitting element disposed on the first electrode and at least partially located in the recess; and a second electrode, on the light emitting element, The area of ​​the bottom surface of the concave portion is larger than the area of ​​the bottom surface of the light emitting element.

2. The display device according to claim 1, wherein: The at least one of the plurality of sub-pixels further includes a reflective layer on the bottom surface and side surfaces of the concave portion.

3. The display device according to claim 1, wherein: The at least one of the plurality of sub-pixels further includes a reflective layer surrounding a portion where the first electrode and the light emitting element are in contact with each other.

4. The display device according to claim 3, wherein: The reflective layer is a part of the first electrode.

5. The display device according to claim 4, wherein: The first electrode includes a reflective metal layer and a non-reflective metal layer on the reflective metal layer, and the reflective layer is formed by exposing a portion of the reflective metal layer through an opening in the non-reflective metal layer.

6. The display device according to claim 5, wherein: The non-reflective metal layer extends to a top surface of the bank, and the portion of the reflective metal layer exposed by the opening in the non-reflective metal layer is on the top surface of the bank.

7. The display device according to claim 3, further comprising an optical layer, wherein: The optical layer is located between the reflective layer and the light emitting element in the concave portion.

8. The display device according to claim 7, further comprising: a contact electrode on one of the one or more insulating layers; as well as A contact hole penetrates the optical layer, and the second electrode contacts the contact electrode through the contact hole.

9. The display device according to claim 8, wherein: The optical layer includes a first optical layer surrounding the light emitting element of the at least one of the plurality of sub-pixels and a second optical layer on the first optical layer.

10. The display device according to claim 9, wherein: The first optical layer includes an organic material in which reflective particles are dispersed.

11. The display device according to claim 10, wherein: The first optical layer and the second optical layer include the same organic material.

12. The display device according to claim 10, wherein: The first optical layer includes an organic material in which reflective particles are dispersed, and the second optical layer includes an organic material without reflective particles. 13 . The display device according to claim 1 , further comprising a black matrix covering the light emitting element of the at least one of the plurality of sub-pixels.

14. The display device according to claim 1, further comprising a black matrix, in, The at least one of the plurality of sub-pixels includes a first light emitting element and a second light emitting element that emit light of the same color, and The black matrix covers one of the first light-emitting element and the second light-emitting element, and does not cover the other of the first light-emitting element and the second light-emitting element.

15. The display device according to claim 1, wherein: The light emitting elements are micro light emitting diodes, and the size of the light emitting elements emitting light of a first color is different from the size of the light emitting elements emitting light of a second color.

16. The display device according to claim 15, wherein: A size of a first recess in which the light emitting element emitting light of the first color is disposed is different from a size of a second recess of the bank pattern in which the light emitting element emitting light of the second color is disposed.

17. The display device according to claim 1, wherein: The first electrode is located on a top surface and a side surface of the at least one of the plurality of protrusions of the bank.

18. The display device according to claim 1, wherein: The second electrode is on the light emitting element of each of the plurality of sub-pixels.

19. The display device according to claim 1, wherein: The at least one of the plurality of sub-pixels includes a first light emitting element and a second light emitting element that emit the same light.

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