Display device

Abstract

A display device according to an exemplary embodiment is disclosed. A display device according to an exemplary embodiment includes: a substrate having a bending area between a display area and a pad area; a planarization film formed on the display area and the pad area in the substrate; a first organic film coated on the planarization film; a second organic film coated on the first organic film; a third organic film coated on the second organic film, in which the third organic film is formed such that an upper surface of the third organic film is flattened in the display area; and a plurality of light emitting elements disposed on the third organic film.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0098313, filed on Jul. 27, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to a display device. Background Art

[0004] As flat display devices, liquid crystal display devices and organic light-emitting display devices are used. Compared with liquid crystal display devices, organic light-emitting display devices have advantages such as improved luminous efficiency, fast response speed, wide viewing angle, etc. However, since organic light-emitting display devices still have low luminous efficiency and include organic materials, organic light-emitting display devices are susceptible to moisture, and thus reliability and lifespan may be reduced.

[0005] Recently, a micro light emitting diode display device is proposed as an inorganic light emitting display device. The micro light emitting diode display device generates an image by providing an inorganic light emitting diode having a size of 100 μm or less in each pixel.

[0006] A micro light emitting diode display device may be manufactured so that at least a portion thereof may be curved. However, in the process of manufacturing the micro light emitting diode display device, the thickness of the curved portion or its adjacent portion is not formed evenly, which causes a problem of improperly transferring the micro light emitting diode when the micro light emitting diode is transferred to the curved portion or its adjacent portion. Summary of the invention

[0007] The present disclosure is directed to solving all of the above described needs and problems.

[0008] The present disclosure provides a display device capable of improving the transfer yield of micro light emitting diodes.

[0009] It should be noted that the objects of the present disclosure are not limited to the above objects, and other objects of the present disclosure will be apparent to those skilled in the art from the following description.

[0010] A display device according to an embodiment of the present specification may include: a substrate having a curved area between a display area and a pad area; a planarization film formed on the display area and the pad area in the substrate; a first organic film coated on the planarization film; a second organic film coated on the first organic film; a third organic film coated on the second organic film, wherein the third organic film is formed so that an upper surface of the third organic film is flattened in the display area; and a plurality of light-emitting elements arranged on the third organic film.

[0011] A display device according to an embodiment of the present specification may include: a substrate having a curved area between a display area and a pad area; a planarization film formed on the display area and the pad area in the substrate; an organic film coated on the planarization film and on the substrate exposed in the curved area, wherein the organic film is formed so that an upper surface of the organic film is flattened in the display area; and a plurality of light-emitting elements transferred to the flattened organic film.

[0012] According to one aspect of the present disclosure, a method for manufacturing a display device is also provided. The method includes: providing a substrate, the substrate having a display area, a pad area, and a bending area between the display area and the pad area; forming a planarization film on the display area and the pad area of ​​the substrate; coating a first organic film covering the planarization film and the bending area on the substrate; coating a second organic film covering the first organic film on the substrate; forming a photoresist pattern in an area corresponding to the bending area of ​​the second organic film; coating a third organic film covering the photoresist pattern on the second organic film; removing the photoresist pattern and a portion of the third organic film using a mask; and transferring a plurality of light-emitting elements to an area corresponding to the display area of ​​the remaining portion of the third organic film; wherein the area corresponding to the display area of ​​the remaining portion of the third organic film has a flat upper surface.

[0013] According to the present disclosure, a photoresist pattern is disposed on the lower organic film corresponding to the bent area, and then, an upper organic film is coated on the lower organic film provided with the photoresist pattern, thereby flattening the upper organic film to prevent non-transfer of the light emitting element.

[0014] According to the present disclosure, non-transfer of a light emitting element can be prevented by using a photoresist pattern, which can lead to process optimization.

[0015] The effects of the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other objects, features and advantages of the present disclosure will become more apparent to those skilled in the art by describing in detail exemplary embodiments of the present disclosure with reference to the accompanying drawings, in which:

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

[0018] Figure 2 yes Figure 1 A magnified view of area 'A' in FIG.

[0019] Figure 3 is a diagram showing a partial area of ​​a pixel;

[0020] Figure 4 is along Figure 3 A cross-sectional view taken along line II' in FIG.

[0021] Figure 5 is along Figure 3 A cross-sectional view taken along line II-II';

[0022] Figure 6 is along Figure 3 A cross-sectional view taken along line III-III';

[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;

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

[0025] Fig. 9 is along Figure 8 A cross-sectional view taken along line IV-IV';

[0026] FIG. 10A to FIG. 10B Is used to describe Figure 1 A diagram showing the shape of the display device shown;

[0027] Fig.11 It is shown Figure 1 A diagram of a longitudinal cross-sectional structure of a display device shown;

[0028] FIG. 12A to FIG. 12C is a diagram for explaining the principle of coating an organic film in a curved region by comparison;

[0029] Fig.13 is a diagram illustrating a method of manufacturing a display device according to an embodiment of the present disclosure; and

[0030] FIG. 14A to FIG. 14I It is shown Fig.13 FIG. 2 is a diagram of the corresponding process of the manufacturing method shown in FIG. DETAILED DESCRIPTION

[0031] The advantages and features of the present specification and the methods for achieving them will become apparent with reference to the preferred embodiments described in detail in conjunction with the accompanying drawings. However, the present specification is not limited to the embodiments to be described below and can be implemented in different forms, and the embodiments are provided only to fully disclose the present disclosure and fully convey the scope of the present disclosure to those skilled in the art, and the present specification is defined by the disclosed claims.

[0032] Since the shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings describing the embodiments of the present disclosure are only exemplary, the present disclosure is not limited to the items shown. Throughout the specification, the same reference numerals indicate the same parts. In addition, when describing the present disclosure, when it is determined that the detailed description of the related known technology may unnecessarily obscure the main points of the present disclosure, its detailed description will be omitted.

[0033] When “including”, “having”, “consisting of”, etc. mentioned in this specification is used, other parts may be added unless “only” is used. Unless otherwise clearly stated, the case of expressing a component in the singular includes the plural form.

[0034] When explaining the components, it should be understood that the error range is included even if there is no separate explicit description.

[0035] In the case of describing a positional relationship, for example, when the positional relationship of two parts is described as "on...", "upper", "lower", "adjacent to...", etc., unless "immediately" or "directly" is used, one or more other parts may be located between the two parts.

[0036] Although "first", "second", etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from other components. Therefore, within the technical spirit of the present disclosure, the first component mentioned below may also be the second component.

[0037] Like reference numerals may refer to substantially like elements throughout this disclosure.

[0038] The following embodiments may be partially or entirely joined or combined with each other and may be linked and operated in various ways in technology. The embodiments may be performed independently or in association with each other.

[0039] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0040] In an embodiment, a photoresist pattern is disposed on the lower organic film corresponding to the bent area, and then an upper organic film is coated on the lower organic film provided with the photoresist pattern to flatten the upper organic film, thereby preventing non-transfer of the light emitting element.

[0041] Figure 1 is a diagram showing a display device according to one embodiment of the present specification; Figure 2 yes Figure 1 An enlarged view of region A; Figure 3 is a diagram showing a partial area of ​​a pixel.

[0042] Reference Figure 1 and Figure 2 A display device according to an embodiment of the present specification includes a display panel 100 that visually reproduces an input image. The display panel 100 may include a display area AA that displays an image and a non-display area NA that does not display an image. In the non-display area NA, various wires and driving circuits may be installed, and a pad portion PAD for connecting an integrated circuit, a printed circuit, etc. may be provided.

[0043] The plurality of light emitting elements 10 disposed in the display area AA to form the pixel PXL may be micro-sized inorganic light emitting elements. The inorganic light emitting elements may be grown on a silicon wafer and then attached to the display panel through a transfer process.

[0044] The transfer process of the light emitting element 10 may be performed for each pre-divided area. Figure 1 , the display area AA is divided into twelve transfer areas ST, but the size or the number of divisions of the transfer area is not limited thereto. The transfer process can be performed sequentially or simultaneously on the first transfer area ST to the twelfth transfer area ST. In the transfer area ST, the blue, green and red light emitting elements 10 can be sequentially transferred, respectively.

[0045] In the non-display area NA, a data driving circuit or a gate driving circuit may be provided, and a conductive line for providing a control signal to control these driving circuits may be provided. Here, the control signal may include various timing signals including a clock signal, an input data enable signal, and a synchronization signal, and may be received by the pad portion PAD.

[0046] The pixel PXL can be driven by a pixel driving circuit. The pixel driving circuit can 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 can be a high potential voltage (EVDD). The cathode voltage can be a low potential voltage (EVSS) usually applied to the pixel. The anode voltage can be a voltage corresponding to the pixel data value of the image signal. The pixel driving circuit can be arranged in the non-display area NA or in the lower part of the display area AA.

[0047] Each of the pixels PXL may include a plurality of sub-pixels, each of which has a different color. For example, the plurality of pixels may include: a red sub-pixel in which a light-emitting element 10 emitting light at a red wavelength is disposed; a green sub-pixel in which a light-emitting element 10 emitting light at a green wavelength is disposed; and a blue sub-pixel in which a light-emitting element 10 emitting light at a green wavelength is disposed. The plurality of pixels may also include a white pixel.

[0048] Reference Figure 2 and Figure 3 , a plurality of pixels PXL may be sequentially arranged in a first direction (X-axis direction) and a second direction (Y-axis direction). Within a pixel of the display area AA, a plurality of sub-pixels of the same color may be arranged. For example, each of the plurality of pixels may include: a first red sub-pixel, in which a first first light-emitting element 11a emitting light at a red wavelength is provided; a second red sub-pixel, in which a first second light-emitting element 11b emitting light at a red wavelength is provided; a first green sub-pixel, in which a second first light-emitting element 12a emitting light at a green wavelength is provided; a second green sub-pixel, in which a second second light-emitting element 12b emitting light at a green wavelength is provided; a first blue sub-pixel, in which a third first light-emitting element 13a emitting light at a blue wavelength is provided; and a second blue sub-pixel, in which a third second light-emitting element 13b emitting light at a blue wavelength is provided. The first first light-emitting element 11a, the second first light-emitting element 12a, and the third first light-emitting element 13a may be interpreted as main light-emitting elements. The first second light emitting element 11 b , the second second light emitting element 12 b , and the third second light emitting element 13 b may be interpreted as sub-light emitting elements.

[0049] One sub-pixel includes one or more light emitting elements, and if one light emitting element becomes faulty, the brightness of another light emitting element may be increased to adjust the brightness of the sub-pixel. However, this is not necessarily limited thereto, and one sub-pixel may include only one light emitting element.

[0050] Each of the plurality of first electrodes 161 may be disposed in the lower portion of the light emitting element 10 and may be selectively connected to the plurality of signal wirings TL1 to TL6 through the extension 161a. A high potential voltage may be applied to the pixel driving circuit through the signal wirings TL to TL6. The signal wirings TL to TL6 and the first electrodes 161 may be formed as an integrated electrode pattern during the electrode patterning process.

[0051] Schematically, the first signal wiring TL1 may be connected to the anode electrode of the first red sub-pixel, and the second signal wiring TL2 may be connected to the anode electrode of the second red sub-pixel. The third signal wiring TL3 may be connected to the anode electrode of the first green sub-pixel, and the fourth signal wiring TL4 may be connected to the anode electrode of the second green sub-pixel. The fifth signal wiring TL5 may be connected to the anode electrode of the first blue sub-pixel, and the sixth signal wiring TL6 may be connected to the anode electrode of the second blue sub-pixel. If one sub-pixel includes only one light-emitting element, the number of signal wirings TL may be reduced by half.

[0052] The second electrode 170 may be a cathode electrode arranged in each row to apply a cathode voltage to the light emitting elements 10 arranged continuously in the first direction (X-axis direction). A plurality of second electrodes 170 may be arranged to 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 electrode 163. Each of the plurality of second electrodes 170 may be electrically connected to the contact electrode 163. However, this is not necessarily limited thereto, and the second electrode 170 may include one electrode layer, rather than being divided into a plurality of electrodes, to serve as a common electrode.

[0053] Figure 4 is along Figure 3 A cross-sectional view taken along line II' in FIG. Figure 5 is along Figure 3 A cross-sectional view taken along line II-II'. Figure 6 is along Figure 3 A cross-sectional view taken along line III-III'. Figure 7 is a cross-sectional view showing an example in which two light emitting elements are connected to a pixel driving circuit.

[0054] Reference Figures 3 to 5 According to an embodiment, the display device includes a plurality of first electrodes 161 and a contact electrode 163 disposed on 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.

[0055] The substrate 110 may be made of a flexible plastic. For example, the substrate 110 may be made of a single-layer or multi-layer substrate of a material selected from polyimide, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyether sulfone, polyarylate, polysulfone, and cycloolefin copolymer, but is not limited thereto. For example, the substrate 110 may be a ceramic substrate or a glass substrate.

[0056] The pixel driving circuit 20 may be disposed in the display area AA on the substrate 110. The pixel driving circuit 20 may include a plurality of thin film transistors using an amorphous silicon semiconductor, a polysilicon semiconductor, or an oxide semiconductor.

[0057] 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, the pixel driving circuit 20 may be formed on the substrate 110 by a thin film transistor (TFT) manufacturing process. In an embodiment, the pixel driving circuit 20 may be a general term for a plurality of thin film transistors electrically connected to the light emitting element 10.

[0058] The pixel driving circuit 20 may be a driving driver manufactured using a metal oxide silicon field effect transistor (MOSFET) manufacturing process on a single crystal semiconductor substrate 110. The driving driver may include a plurality of pixel driving circuits for driving a plurality of sub-pixels. When the pixel driving circuit 20 is implemented as a driving driver, after an adhesive layer is provided on the substrate 110, the driving driver may be mounted on the adhesive layer through a transfer process.

[0059] 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 such as photosensitive photoacrylic or photosensitive polyimide, but is not limited thereto.

[0060] The buffer layer 121 may be used by stacking an inorganic insulating material such as silicon nitride (SiNx) or silicon oxide (SiO2) in a plurality of layers, and may be used by stacking an organic insulating material and an inorganic insulating material in a plurality of layers.

[0061] The insulating layer 122 may be disposed on the buffer layer 121. The insulating layer 122 may be made of an organic insulating material such as photosensitive photoacrylic or photosensitive polyimide, but is not limited thereto. The connection wirings RT1 and RT2 may be disposed on the buffer layer 121. The connection wirings RT1 and RT2 may be connected through corresponding signal wirings TL1 to TL6, or may be connected to the signal wirings TL1 to TL6. The connection wirings RT1 and RT2 may include a plurality of wiring patterns disposed on different layers with one or more insulating layers interposed therebetween. The wiring patterns disposed on different layers may be electrically connected via contact holes through which the insulating layers pass.

[0062] A plurality of bank patterns 130 may be provided on the insulating layer 122. At least one light emitting element 10 may be provided on each bank pattern 130. For example, a first light emitting element 11 may be provided on the first bank pattern 130, a second light emitting element 12 may be provided on the second bank pattern 130, and a third light emitting element 13 may be provided on the third bank pattern 130.

[0063] The bank pattern 130 may be made of an organic insulating material such as photosensitive acrylic or photosensitive polyimide, but is not limited thereto. The bank pattern 130 may guide a position where the light emitting element 10 will be attached during the transfer process of the light emitting element 10. The bank pattern 130 may be omitted.

[0064] The solder pattern 162 may be disposed on the first electrode 161. The solder pattern 162 may be made of indium (In), tin (Sn), or an alloy thereof, but is not limited thereto.

[0065] A plurality of light emitting elements 10 may be mounted on the solder pattern 162, respectively. One pixel may include three colors of light emitting elements 10. 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.

[0066] The first optical layer 141 may cover the plurality of light emitting elements 10 and the dam patterns 130. Therefore, the first optical layer 141 may cover between the plurality of light emitting elements 10 and between the plurality of dam patterns 130. The first optical layer 141 may extend in the first direction (X) and be spaced apart in the second direction (Y) to be separated between pixel rows.

[0067] The first optical layer 141 may include an organic insulating material in which fine metal particles such as 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 to be emitted outward.

[0068] 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 thin electrode through which light is transmitted. The second electrode 170 may be a transparent electrode material such as indium tin oxide (ITO), but is not necessarily limited thereto.

[0069] The second electrode 170 may extend in the first direction (X-axis direction) and be spaced apart in the second direction (Y-axis direction). 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 contacting and electrically connected to the contact electrode 163, and a third region 173 disposed on one side of the first optical layer 141 and connecting the first region 171 and the second region 172.

[0070] On a plane, each of the plurality of second electrodes 170 may overlap the first optical layer 141 , and the second region 172 may cover a plane outside the first optical layer 141 .

[0071] The second optical layer 142 may be an organic insulating material surrounding 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., siloxane). For example, the first optical layer 141 may be siloxane containing titanium oxide (TiOx), and the second optical layer 142 may be siloxane not containing titanium oxide (TiOx). However, this is not necessarily limited to this, and the first optical layer 141 and the second optical layer 142 may be formed of the same material, or may be formed of different materials.

[0072] According to an embodiment, since the second region 172 of the second electrode 170 is connected to the contact electrode 163 in an overall flat state, excessive stress is not concentrated at the point of connection with the contact electrode 163. Therefore, cracks in the second electrode 170 may be effectively prevented.

[0073] 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 coplanar. In other words, the first optical layer 141 and the second optical layer 142 may function as a planarization layer. Therefore, a pattern of the black matrix 190 may be easily formed on the first optical layer 141 and the second optical layer 142 because there is no step on the surface where the black matrix 190 is formed. However, this is not necessarily limited to this, and the second optical layer 142 and the top surface of the second electrode 170 may have different heights.

[0074] The black matrix 190 may be an organic insulating material to which a black pigment is added. Under the black matrix 190, the second electrode 170 may be in contact with the contact electrode 163. Transmission holes 191 may be formed between patterns of the black matrix 190, and light emitted from the light emitting element 10 is emitted outward through the transmission holes 191. The problem of mixing light emitted from adjacent light emitting elements 10 by the first optical layer 141 may be improved by the black matrix 190.

[0075] The capping layer 180 may be an organic insulating material for covering the black matrix 190 and the second electrode 170. Figure 3 , the configuration of the black matrix 190 and the cover layer 180 is omitted.

[0076] The contact electrode 163 is electrically connected to the first connection wiring RT1 disposed on the lower portion thereof, and the first connection wiring RT1 may be connected to the pixel driving circuit 20. Therefore, a cathode voltage may be applied to the second electrode 170 through the contact electrode 163. The first electrode 161 may be electrically connected to the second connection wiring RT2. This will be described later.

[0077] Reference Figure 5 , the contact electrode 163 and the signal wirings TL1 to TL6 may be disposed on the same plane. The pixel driving circuit 20 may be disposed on the lower portion of the contact electrode 163 and the signal wirings TL1 to TL6. When the pixel driving circuit 20 is a driving driver, a plurality of driving drivers may be disposed in the display panel.

[0078] The passivation layer 133 may expose the contact electrode 163 so that the contact electrode 163 and the second electrode 170 are electrically connected. In addition, the passivation layer 133 may insulate the signal wirings TL2 to TL5 from the second electrode 170 .

[0079] Reference Figure 6 The connection portion 161 a of the first electrode 161 extends to one side surface 131 of the bank pattern 130 and is electrically connected to the connection wiring RT2 provided on the insulating layer 122 .

[0080] The first electrode 161, the connection portion 161a, the signal wiring TL and / or the connection wiring RT1 and RT2 may include a single layer or multiple layers of a metal layer selected from titanium (Ti), molybdenum (Mo) and aluminum (Al). The first electrode 161, the connection portion 161a, the signal wiring TL and / or the connection wiring RT1 and RT2 may be formed into a multilayer structure including a first layer ML1, a second layer ML2, a third layer ML3 and a fourth layer ML.

[0081] The first layer ML1 and the third layer ML3 may include titanium (Ti) or molybdenum (Mo). The second layer ML2 may include aluminum (Al). The fourth layer ML4 may include a transparent conductive oxide layer, such as indium tin oxide (ITO) or indium zinc oxide (IZO), which has good adhesion, corrosion resistance, and acid resistance to the solder pattern 162.

[0082] The first layer ML1 , the second layer ML2 , the third layer ML3 , and the fourth layer ML4 may be sequentially deposited and then patterned by performing a photolithography process and an etching process.

[0083] The passivation layer 133 may be disposed on the first electrode 161 and the signal wiring TL, and may include an opening hole 133 a exposing the solder pattern 162 .

[0084] 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. A first driving electrode 15 may be disposed on a lower portion of the first conductive type semiconductor layer 10-1, and a second driving electrode 14 may be disposed on an upper portion of the second conductive type semiconductor layer 10-3.

[0085] The light emitting element 10 can be formed on a silicon wafer using methods 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), sputtering, etc.

[0086] The first conductive type semiconductor layer 10-1 may be implemented as a compound semiconductor such as a group III-V, group II-VI, etc., and may be doped with a first dopant. The first conductive type semiconductor layer 10-1 may be made of a composition formula of Al x1 In y1 Ga (1-x1-y1) The first conductive semiconductor layer 10-1 may be formed of any one or more of semiconductor materials of N (0≤x1≤1, 0≤y1≤1, O≤x1+y1≤1), InAlGaN, AlGaAs, GaP, GaAs, and AlGaInP, but is not limited thereto. When the first dopant is an n-type dopant such as Si, Ge, Sn, Se, Te, etc., the first conductive 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 semiconductor layer 10-1 may be a p-type nitride semiconductor layer.

[0087] The active layer 10-2 is a layer where electrons (or holes) injected through the first conductive semiconductor layer 10-1 meet holes (or electrons) injected through the second conductive semiconductor layer 10-3. The active layer 10-2 can generate light that transitions to a lower energy level and has a corresponding wavelength as electrons and holes recombine.

[0088] 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, or a quantum wire structure, and the structure of the active layer 10-2 is not limited thereto. The active layer 10-2 may generate light in a visible light band. Schematically, the active layer 10-2 may output light in any one of a blue band, a green band, and a red band.

[0089] The second conductive type semiconductor layer 10-3 may be disposed on the active layer 10-2. The second conductive type semiconductor layer 10-3 may be implemented as a compound semiconductor such as a III-V group, a II-VI group, etc., and the second conductive type semiconductor layer 10-3 may be doped with a second dopant. The second conductive type semiconductor layer 10-3 may be composed of a composition formula of In x2 Al y2 Ga1 -x-2+y2The second conductive semiconductor layer 10-3 may be formed of a semiconductor material selected from the group consisting of AlInN, AlGaAs, GaP, GaAs, GaAsP and AlGaInP. When the second dopant is a p-type dopant such as Mg, Zn, Ca, Sr, Ba, etc., the second conductive semiconductor layer 10-3 doped with the second dopant may be a p-type semiconductor layer. When the second dopant is an n-type dopant, the second conductive semiconductor layer 10-3 may be an n-type nitride semiconductor layer.

[0090] A reflective layer 16 may be provided on the side surface and the lower portion of the light emitting element 10. The reflective layer 16 may have a structure in which a reflective material is dispersed in a resin layer, but is not necessarily limited thereto. Schematically, the reflective layer 16 may be manufactured as a reflector of various structures. The light emitted from the active layer 10-2 may be reflected upward by the reflective layer 16 to improve light extraction efficiency.

[0091] Although the embodiment is described as a vertical structure in which the driving electrodes 14 and 15 are disposed on the upper and lower portions of the light emitting structure, the light emitting device may have a lateral structure or a flip chip structure in addition to the vertical structure.

[0092] Reference Figure 7 , a main light emitting element 12a and a sub light emitting element 12b of a sub-pixel may be disposed on the bank pattern 130. The second light emitting element 12 will be schematically 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 wiring RT21 disposed on the lower portion of the first first electrode 161-1. 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 wiring RT22 disposed on the lower portion of the first second electrode 161-2.

[0093] The pixel driving circuit 20 can apply an anode voltage to the main light emitting element 12a through the second first connection wiring RT21, and can apply an anode voltage to the sub light emitting element 12b through the second second connection wiring RT22. The pixel driving circuit 20 can apply a cathode voltage to the main light emitting element 12a and the sub light emitting element 12b through the first connection wiring RT1 and the second electrode 170.

[0094] 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. If the main light emitting element 12a becomes dark, the brightness can be adjusted by driving only the sub-light emitting element 12b.

[0095] Figure 8is a diagram illustrating a display device according to another embodiment of the present specification. Fig. 9 is along Figure 8 A cross-sectional view taken along line IV-IV'.

[0096] Reference Figure 8 and Fig. 9 , the second electrode 170 may be electrically connected to the contact electrode 163 via a 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 may be inserted into the contact hole TH1 of the second optical layer 142 and may contact an upper surface of the contact electrode 163. The contact hole TH1 may be formed in an outer region of the pixel.

[0097] FIG. 10A to FIG. 10B Is used to describe Figure 1 A diagram showing the shape of a display device is shown.

[0098] Reference Figures 10A to 10B , a display device according to an embodiment of the present disclosure may include a display area or display region AA, a bezel region BZ corresponding to a non-display area, a bending area BA, and a pad portion PAD.

[0099] The bending area BA may be formed between the bezel area BZ and the pad portion PAD and may be bent. As the bending area BA is bent, the pad portion PAD may be placed under the display panel 100 .

[0100] Fig.11 It is shown Figure 1 A diagram showing a longitudinal cross-sectional structure of a display device shown.

[0101] Reference Fig.11 , a display device according to an embodiment of the present disclosure may include a substrate 110, a buffer layer 121, an insulating layer 122, a bank pattern 130, a first optical layer 141, a second optical layer 142, a black matrix 190, and a cover layer 180. Here, the buffer layer 121 may include a multi-buffer layer 121a, an adhesive layer 121b, and a planarization film 121c, and the insulating layer 122 may include a via contact layer 122a, a first organic film 122b, a second organic film 122c, a third organic film 122d, and conductor patterns M0, M1, M2, M3, and M4.

[0102] The multi-buffer layer 121a may be disposed on the substrate 110. The multi-buffer layer 121a may be disposed only in the display area AA, the bezel area BZ, and the pad area PAD except the bending area BA. The multi-buffer layer 121a may be formed of an organic insulating material such as, but not limited to, photosensitive photoacrylic or photosensitive polyimide.

[0103] In addition, the multi-buffer layer 121a may be used by stacking an inorganic insulating material such as silicon nitride (SiNx) or silicon oxide (SiO2) in multiple layers, and may be used by stacking an organic insulating material and an inorganic insulating material in multiple layers.

[0104] The adhesive layer 121b may be disposed on the multi-buffer layer 121a. The adhesive layer 121b may be disposed on the multi-buffer layer 121a and on the substrate 110 exposed by the multi-buffer layer 121a in the bending area BA. The adhesive layer 121b may be formed of acrylic resin, silicone resin, etc., but is not limited thereto.

[0105] The planarization film 121c may be disposed on the adhesive layer 121b. The planarization film 121c may be disposed only in the display area AA, the bezel area BZ, and the pad area PAD except the bending area BA. The planarization film 121c may be formed of an organic insulating material such as, but not limited to, photosensitive photoacrylic or photosensitive polyimide.

[0106] The first conductor pattern M0 may be disposed on the planarization film 121c, and a via contact layer 122a covering the first conductor pattern M0 may be disposed. The first conductor pattern M0 may be disposed on the planarization film 121c and on the adhesive layer 121b exposed by the planarization film 121c in the bending region.

[0107] The second conductor pattern M1 may be disposed on the via contact layer 122a, and a first organic film 122b covering the second conductor pattern M1 may be disposed. The second conductor pattern M1 may be disposed in the display area AA, the bezel area BZ, and the pad area PAD except the bending area BA.

[0108] The third conductor pattern M2 may be disposed on the first organic film 122b, and a second organic film 122c covering the third conductor pattern M2 may be disposed. The third conductor pattern M2 may be disposed in the display area AA, the bezel area BZ, and the pad area PAD except the bending area BA.

[0109] The fourth conductor pattern M3 may be disposed on the second organic film 122c, and the third organic film 122d covering the fourth conductor pattern M3 may be disposed. The fourth conductor pattern M3 may be disposed in the display area AA, the bezel area BZ, and the pad portion PAD except the bending area BA.

[0110] The fifth conductor pattern M4 may be disposed on the third organic film 122d. The fifth conductor pattern M4 may be disposed in the display area AA, the bezel area BZ excluding the bending area BA, and the pad portion PAD.

[0111] The bank pattern 130 may be disposed on the third organic film 122d, and the light emitting element 10 may be disposed on the bank pattern 130. The bank pattern 130 may be disposed under one light emitting element or two light emitting elements. The bank pattern 130 may be formed of an organic insulating material such as, but not limited to, photosensitive acrylic or photosensitive polyimide. During the transfer process of the light emitting element, the bank pattern 130 may guide the position where the light emitting element will be attached. The bank pattern 130 may be omitted.

[0112] In the display device according to the embodiment of the present disclosure, a groove is formed in the bending area BA, and considering the bending area formed with the groove, the organic film in the display area AA must be formed so that the organic film is flattened to prevent a defect in which the light emitting element is not properly transferred during the process of transferring the light emitting element. In particular, the upper surface of the third organic film 122d that affects the transfer of the light emitting element will be flattened.

[0113] FIG. 12A to FIG. 12C This is a diagram for explaining the principle of coating an organic film in a curved region by comparison.

[0114] When the first organic film 122b, the second organic film 122c and the third organic film 122d are sequentially deposited in the display area AA, the upper surface of the third organic film 122d is not flattened toward the groove area and is inclined from the curved area to the groove area, which causes defects when transferring the light emitting element 10 to the third organic film 122d.

[0115] Therefore, in an embodiment, a photoresist pattern will be used to deposit an organic film.

[0116] That is to say, referring to Fig. 12A , a first organic film 122b is deposited on the via contact layer 122a, a second organic film 122c is deposited on the first organic film 122b, and then a third organic film 122d is deposited using a photoresist pattern (PR).

[0117] When Fig. 12B When the third organic film 122 d is deposited and patterned using the photoresist pattern PR as shown, the upper surface of the third organic film 122 d may not be inclined toward the horizontal line L but remain flat.

[0118] Therefore, in this embodiment, the third organic film is flattened using a photoresist pattern. When the upper surface of the third organic film is flattened, the transfer of the light emitting element to the third organic film will not cause defects.

[0119] Reference Fig. 12C, shows an example in which a first organic film 122b is deposited on the via contact layer 122a, a second organic film 122c is deposited on the first organic film 122b using a photoresist pattern PR, and a third organic film 122d is deposited.

[0120] and Fig. 12A Differently, when a photoresist pattern (PR) is used before depositing the second organic film 122c, the upper surface of the second organic film 122c is flattened as the second organic film 122c is removed from the curved area, so that the upper surface of the third organic film 122d deposited on the upper surface of the second organic film 122c is also flattened, and therefore, no defects occur when the light emitting element 10 is transferred to the upper surface of the third organic film 122d.

[0121] Fig.13 is a diagram illustrating a method of manufacturing a display device according to an embodiment of the present disclosure. FIG. 14A to FIG. 14I It is shown Fig.13 The corresponding process of the manufacturing method shown in FIG. For the convenience of drawing symbols, FIG. 14A to FIG. 14I The conductor patterns M0 to M4 are not shown.

[0122] Reference Fig.13 and Fig.14A , the substrate 110, the multi-buffer layer 121a, the adhesive layer 121b, the planarization film 121c and the via contact layer 122a may be sequentially stacked (S110). In this process, the via contact layer 122a covering the first conductor pattern M0 may be stacked after the first conductor pattern M0 is formed on the planarization film 121c.

[0123] Reference Fig.13 and Fig. 14B , a first organic film 122b may be formed on the via contact layer 122a (S120). In this process, after the second conductor pattern M1 is formed on the via contact layer 122a, the first organic film 122b covering the second conductor pattern M1 may be formed.

[0124] Reference Fig.13 and Fig. 14C , the second organic film 122c may be formed on the first organic film 122b (S130). In this process, the third conductive line pattern M2 may be formed on the first organic film 122b, and then, the second organic film 122c covering the third conductive line pattern M2 may be formed.

[0125] Reference Fig.13 and Fig.14D, a photoresist (PR0) may be coated on the second organic film 122c (S140). In this process, a fourth conductor pattern M3 is formed on the second organic film 122c, and then, a photoresist (PR0) covering the fourth conductor pattern M3 may be coated.

[0126] Reference Fig.13 and Fig.14E , a photoresist pattern PR may be formed by performing an exposure process on the photoresist (PR0) formed on the second organic film 122c as a mask (S150).

[0127] Reference Fig.13 and Fig.14F , a third organic film 122 d may be coated on the second organic film 122 c where the photoresist pattern PR is formed ( S160 ).

[0128] Reference Fig.13 and Figure 14G , a mask may be used to expose an upper portion of the third organic film 122d (S170).

[0129] Reference Fig.13 and Fig.14H , the upper surface of the third organic film 122d can be flattened by performing an exposure process on the third organic film 122d and removing the third organic film 122d and the photoresist pattern PR corresponding to the bending area (S180). Therefore, although the third organic film 122d can be formed in the display area, the frame area, and the pad area except the bending area, the upper surface of the third organic film 122d can be flattened.

[0130] Reference Fig.13 and Fig.14I , the light emitting element 10 may be transferred to the third organic film 122d corresponding to the display area (S190). Since the upper surface of the third organic film 122d may have been flattened, the light emitting element may be easily transferred to the upper surface of the third organic film 122d, thereby improving the transfer yield.

[0131] According to one or more embodiments of the present disclosure, a display device may be described as follows.

[0132] According to one or more embodiments of the present disclosure, a display device may include: a substrate having a curved area between a display area and a pad area; a planarization film formed on the display area and the pad area in the substrate; a first organic film coated on the planarization film; a second organic film coated on the first organic film; a third organic film coated on the second organic film, wherein the third organic film is formed so that an upper surface of the third organic film is flattened in the display area; and a plurality of light-emitting elements arranged on the third organic film.

[0133] The display device may further include: a multi-buffer layer formed on the display region and the pad region in the substrate; and an adhesive layer formed between the multi-buffer layer and the planarization film.

[0134] The display device may further include a via contact layer formed on the planarization film and in the bent region of the substrate.

[0135] The third organic film may be flattened by a photoresist pattern disposed on the second organic film corresponding to the bent region.

[0136] The third organic film may be formed on the display region and the pad region.

[0137] The second organic film may have an upper surface flattened by a photoresist pattern disposed on the first organic film corresponding to the bent region.

[0138] The display device may further include a first conductor pattern disposed on the planarization film, and the via contact layer may be formed on the planarization film on which the first conductor pattern is formed.

[0139] The first conductor pattern may be formed on the planarization film and on the adhesive layer exposed in the bending region.

[0140] The display device may further include a second conductive line pattern disposed on the via contact layer, and the first organic film is formed on the via contact layer provided with the second conductive line pattern.

[0141] The display device may further include a third conductive line pattern provided on the first organic film, and the second organic film is formed on the first organic film provided with the third conductive line pattern.

[0142] The display device may further include a fourth conductive line pattern disposed on the second organic film, and the third organic film is formed on the second organic film provided with the fourth conductive line pattern.

[0143] The display device may further include a fifth conductor pattern disposed on the third organic film.

[0144] According to one or more embodiments of the present disclosure, a display device may include: a substrate having a curved area between a display area and a pad area; a planarization film formed on the display area and the pad area in the substrate; an organic film coated on the planarization film and on the substrate exposed in the curved area, wherein the organic film is formed so that an upper surface of the organic film is flattened in the display area; and a plurality of light-emitting elements transferred to the flattened organic film.

[0145] The display device may further include: a multi-buffer layer formed on the display region and the pad region in the substrate; and an adhesive layer formed between the multi-buffer layer and the planarization film.

[0146] The display device may further include a via contact layer formed on the planarization film and in the bent region of the substrate.

[0147] The organic film may be flattened by a photoresist pattern disposed in the curved region.

[0148] Although the embodiments of the present disclosure have been described in more detail with reference to the accompanying drawings, the present disclosure is not limited thereto and can be implemented in many different forms without departing from the technical concept of the present disclosure. Therefore, the embodiments disclosed in the present disclosure are provided for illustrative purposes only and are not intended to limit the technical concept of the present disclosure. The scope of the technical concept of the present disclosure is not limited thereto. Therefore, it should be understood that the above embodiments are illustrative in all aspects and do not limit the present disclosure.

Claims

1. A display device, comprising: A substrate having a curved region between the display region and the pad region; A planarization film formed on the display area and the pad area in the substrate; A first organic film coated on the planarization film; a second organic film coated on the first organic film; a third organic film coated on the second organic film, wherein the third organic film is formed so that an upper surface of the third organic film is flattened in the display area; as well as A plurality of light emitting elements are arranged on the third organic film.

2. The display device according to claim 1, further comprising: A multi-buffer layer is formed on the display area and the pad area in the substrate; as well as An adhesive layer is formed between the multi-buffer layer and the planarization film.

3. The display device according to claim 2, further comprising: A via contact layer is formed on the planarization film and in the curved region of the substrate.

4. The display device according to claim 1, wherein: The third organic film is flattened by a photoresist pattern disposed on the second organic film corresponding to the bent region.

5. The display device according to claim 1, wherein: The third organic film is formed on the display area and the pad area.

6. The display device according to claim 1, wherein: The second organic film has an upper surface flattened by a photoresist pattern disposed on the first organic film corresponding to the bent region.

7. The display device according to claim 3, further comprising: A first conductor pattern is provided on the planarization film, The via contact layer is formed on the planarization film on which the first conductor pattern is formed.

8. The display device according to claim 7, wherein: The first conductor pattern is formed on the planarization film and on the adhesive layer exposed in the bending region.

9. The display device according to claim 7, further comprising: A second conductor pattern is arranged on the via contact layer, The first organic film is formed on the via contact layer provided with the second conductor pattern.

10. The display device according to claim 9, further comprising: A third conductor pattern is provided on the first organic film, The second organic film is formed on the first organic film provided with the third conductor pattern.

11. The display device according to claim 10, further comprising: a fourth conductor pattern, disposed on the second organic film, The third organic film is formed on the second organic film provided with the fourth conductor pattern.

12. The display device according to claim 11, further comprising: The fifth conductor pattern is arranged on the third organic film.

13. A display device, comprising: A substrate having a curved region between the display region and the pad region; A planarization film formed on the display area and the pad area in the substrate; an organic film coated on the planarization film and on the substrate exposed in the curved region, wherein the organic film is formed such that an upper surface of the organic film is flattened in the display region; as well as Multiple light emitting elements are transferred onto the flattened organic film.

14. The display device according to claim 13, further comprising: A multi-buffer layer is formed on the display area and the pad area in the substrate; as well as An adhesive layer is formed between the multi-buffer layer and the planarization film.

15. The display device according to claim 14, further comprising: A via contact layer is formed on the planarization film and in the curved region of the substrate.

16. The display device according to claim 13, wherein: The organic film is flattened by a photoresist pattern disposed in the bent region.

17. A method for manufacturing a display device, comprising: Providing a substrate, the substrate having a display area, a pad area, and a bending area between the display area and the pad area; forming a planarization film on the display area and the pad area of ​​the substrate; coating a first organic film covering the planarization film and the curved area on the substrate; coating a second organic film covering the first organic film on the substrate; forming a photoresist pattern in a region of the second organic film corresponding to the bent region; coating a third organic film covering the photoresist pattern on the second organic film; removing the photoresist pattern and a portion of the third organic film using a mask; as well as transferring a plurality of light emitting elements to a region of the remaining portion of the third organic film corresponding to the display region; The remaining portion of the third organic film has a flat upper surface in an area corresponding to the display area.

18. The method according to claim 17, further comprising: forming a multi-buffer layer on the display area and the pad area in the substrate; as well as An adhesive layer is formed between the multi-buffer layer and the planarization film.

19. The method according to claim 18, further comprising: A via contact layer is formed on the planarization film and in a curved region of the substrate.

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