Display device

Abstract

One aspect of the present disclosure provides a display device including: a display panel including a plurality of sub-pixels; a reflective electrode disposed in each of the plurality of sub-pixels; a first light emitting element disposed on the reflective electrode; a first connection electrode disposed on the first light emitting element and configured such that at least a portion of the first connection electrode covers the first light emitting element; and a second light emitting element disposed on the first connection electrode and configured to overlap the first light emitting element, in which the first light emitting element has a larger size than the second light emitting element. Accordingly, the first light emitting element has a larger size so that the second light emitting element can be more easily aligned and disposed on the first light emitting element.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority of Korean Patent Application No. 10-2023-0151786 filed on November 6, 2023 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a display device, and in particular to a display device using a light emitting diode (LED). Background Art

[0004] As display devices used for monitors of computers, televisions, mobile phones, and the like, there are organic light emitting displays (OLEDs) configured for autonomous emission and liquid crystal displays (LCDs) requiring a separate light source.

[0005] The application range of the display device is diversified from monitors of computers and televisions to personal mobile devices, and research on a display device having a wide display area and having reduced volume and weight is being conducted.

[0006] In addition, recently, a display device including a light emitting diode (LED) has attracted attention as a next-generation display device. Since LEDs are made of inorganic materials rather than organic materials, LEDs are more reliable and have a longer life than liquid crystal display devices or organic light emitting display devices. In addition, LEDs can be turned on or off quickly, have excellent luminous efficiency, high impact resistance and high stability, and display high-brightness images. Summary of the invention

[0007] An object to be achieved by the present disclosure is to provide a display device in which a first light emitting element and a second light emitting element are vertically stacked to reduce the area of ​​a sub-pixel.

[0008] Another object to be achieved by the present disclosure is to provide a display device in which a first light emitting element has a relatively large size so that a second light emitting element can be easily aligned on the first light emitting element.

[0009] Still another object to be achieved by the present disclosure is to provide a display device in which a first connection electrode made of a material having high reflection efficiency is formed between a first light emitting element and a second light emitting element to improve light extraction efficiency.

[0010] Still another object to be achieved by the present disclosure is to provide a display device having improved viewing angle characteristics and brightness in both a forward direction and a lateral direction.

[0011] Still another object to be achieved by the present disclosure is to provide a display device in which a first connection electrode having high reflection efficiency is formed on a lower portion of a second light emitting element to improve light extraction efficiency and brightness.

[0012] Another object to be achieved by the present disclosure is to provide a display device in which a plurality of opening portions are formed in a first connection electrode to improve efficiency in extracting light emitted from a first light emitting element.

[0013] Another additional purpose of the present disclosure is to provide a display device, in which the first connecting electrode includes a transparent first electrode layer and an opaque second electrode layer, and the second electrode layer is patterned to form a plurality of transmissive portions, thereby improving the efficiency of extracting light emitted from the first light-emitting element.

[0014] Yet another object of the present disclosure is to provide a display device in which a plurality of light scattering particles are formed around a first light emitting element so that light captured in the display device can be easily emitted toward the outside of the display device, thereby improving luminous efficiency and brightness.

[0015] The objects of the present disclosure are not limited to the above-mentioned objects, and other objects not mentioned above may be clearly understood by those skilled in the art from the following description.

[0016] One aspect of the present disclosure provides a display device, the display device comprising: a display panel, the display panel comprising a plurality of sub-pixels; a reflective electrode, the reflective electrode being disposed in each of the plurality of sub-pixels; a first light-emitting element, the first light-emitting element being disposed on the reflective electrode; a first connecting electrode, the first connecting electrode being disposed on the first light-emitting element and being configured such that at least a portion of the first connecting electrode covers the first light-emitting element; and a second light-emitting element, the second light-emitting element being disposed on the first connecting electrode and being configured to overlap with the first light-emitting element, wherein the first light-emitting element has a larger size than the second light-emitting element. Therefore, the first light-emitting element has a relatively large size, so that the second light-emitting element can be more easily aligned and disposed on the first light-emitting element.

[0017] Additional details of example embodiments are included in the detailed description and the accompanying drawings.

[0018] According to the present disclosure, the first light emitting element and the second light emitting element are stacked vertically, which can reduce the area of ​​a sub-pixel and realize a display device capable of displaying a high-resolution image.

[0019] According to the present disclosure, the first light emitting element has a relatively large size, so that the second light emitting element can be easily aligned on the first light emitting element.

[0020] According to the present disclosure, a first connection electrode made of a material having high reflection efficiency is formed between a first light emitting element and a second light emitting element, thereby improving viewing angle characteristics and brightness in both a forward direction and a lateral direction.

[0021] According to the present disclosure, the first connection electrode having high reflection efficiency is formed on the lower portion of the second light emitting element, thereby improving light extraction efficiency and brightness.

[0022] According to the present disclosure, a plurality of opening portions are formed in the first connection electrode, thereby improving efficiency in extracting light emitted from the first light emitting element.

[0023] According to the present disclosure, the first connection electrode includes a transparent first electrode layer and an opaque second electrode layer, and the second electrode layer is patterned to form a plurality of transmission portions, thereby improving efficiency in extracting light emitted from a first light emitting element.

[0024] According to the present disclosure, a plurality of light scattering particles are formed around the first light emitting element, thereby enabling light captured in the display device to be easily emitted toward the outside of the display device.

[0025] The effects according to the present disclosure are not limited to those exemplified above, and more various effects are included in the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and other aspects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0027] Figure 1 is a schematic configuration diagram of a display device according to an embodiment of the present disclosure;

[0028] Figure 2A is a partial cross-sectional view of a display device according to an embodiment of the present disclosure;

[0029] Figure 2B is a perspective view of a tiled display device according to an embodiment of the present disclosure;

[0030] Figure 3 is a schematic enlarged top view of a sub-pixel of a display device according to an embodiment of the present disclosure;

[0031] Figure 4 is a cross-sectional view of a sub-pixel of a display device according to an embodiment of the present disclosure;

[0032] Figure 5A is a schematic enlarged top view of a sub-pixel of a display device according to another embodiment of the present disclosure;

[0033] Figure 5B is a schematic enlarged top view of a sub-pixel of a display device according to another embodiment of the present disclosure;

[0034] Figure 6 is a schematic enlarged top view of a sub-pixel of a display device according to yet another embodiment of the present disclosure;

[0035] Figure 7 is a cross-sectional view of a sub-pixel of a display device according to yet another embodiment of the present disclosure;

[0036] FIG. 8A to FIG. 9B is a schematic enlarged top view of a sub-pixel of a display device according to various embodiments of the present disclosure; and

[0037] Fig.10 is a cross-sectional view of a sub-pixel of a display device according to still another embodiment of the present disclosure. DETAILED DESCRIPTION

[0038] By referring to the exemplary embodiments described in detail below in conjunction with the accompanying drawings, the advantages and features of the present disclosure and the methods for achieving these advantages and features will be clear. However, the present disclosure is not limited to the exemplary embodiments disclosed herein, but will be implemented in various forms. The exemplary embodiments are provided only by way of example so that those skilled in the art can fully understand the disclosure of the present disclosure and the scope of the present disclosure.

[0039] The shapes, sizes, ratios, angles, numbers, etc. shown in the drawings for describing the exemplary embodiments of the present disclosure are merely examples, and the present disclosure is not limited thereto. Throughout the disclosure, the same reference numerals generally represent the same elements. In addition, in the following description of the present disclosure, the detailed description of known related technologies may be omitted to avoid unnecessarily obscuring the subject matter of the present disclosure. Terms such as "including", "having" and "consisting of..." used herein are generally intended to allow the addition of other components, unless these terms are used together with the term "only". Unless otherwise expressly stated, reference to the singular may include the plural.

[0040] Even if not explicitly stated, the components are interpreted as including the ordinary error range.

[0041] When terms such as “on,” “over,” “below,” and “adjacent” are used to describe the positional relationship between two components, one or more components may be positioned between the two components unless these terms are used together with the terms “immediately” or “directly.”

[0042] When an element or layer is disposed “on” another element or layer, the other element or layer may be directly on the other element or interposed between the other elements.

[0043] Although the terms "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, the first component to be mentioned below can be the second component in the technical concept of the present disclosure.

[0044] Like reference numbers generally refer to like elements throughout the disclosure.

[0045] The size and thickness of each component shown in the drawings are illustrated for convenience of description, and the present disclosure is not limited to the size and thickness of the components shown.

[0046] The features of the various embodiments of the present disclosure may be partially or completely dependent on or combined with each other, and may be technically interlocked and operated in various ways, and these embodiments may be performed independently or in association with each other.

[0047] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0048] Figure 1 is a schematic configuration diagram of a display device according to an embodiment of the present disclosure. For ease of description, Figure 1 Among various constituent elements of the display device 100 , only the display panel PN, the gate driving part GD, the data driving part DD, and the timing controller TC are shown.

[0049] Reference Figure 1 The display device 100 includes a display panel PN having a plurality of sub-pixels SP, a gate driving part GD configured to supply various types of signals to the display panel PN, and a timing controller TC configured to control a data driving part DD, the gate driving part GD, and the data driving part DD.

[0050] The gate driving part GD supplies a plurality of scan signals to the plurality of scan lines SL in response to a plurality of gate control signals provided from the timing controller TC. Figure 1 It is shown that a single gate driving part GD is disposed to be spaced apart from one side of the display panel PN. However, the number and arrangement of the gate driving parts GD are not limited thereto.

[0051] The data driving part DD supplies data voltages to the plurality of data lines DL in response to a plurality of data control signals and image data provided from the timing controller TC. The data driving part DD may convert the image data into data voltages by using reference gamma voltages and supply the converted data voltages to the plurality of data lines DL.

[0052] The timing controller TC aligns the image data input from the outside and supplies the image data to the data driving part DD. The timing controller TC can generate a gate control signal and a data control signal by using synchronization signals input from the outside, namely, a dot clock signal, a data enable signal, and a horizontal / vertical synchronization signal. In addition, the timing controller TC can control the gate driving part GD and the data driving part DD by supplying the generated gate control signal and data control signal to the gate driving part GD and the data driving part DD.

[0053] The display panel PN is configured to display an image to a user and includes a plurality of sub-pixels SP. In the display panel PN, a plurality of scan lines SL and a plurality of data lines DL may cross each other, and a plurality of sub-pixels SP may be formed at intersections between the scan lines SL and the data lines DL.

[0054] A display area AA and a non-display area NA may be defined on the display panel PN.

[0055] The display area AA is an area in which an image is displayed in the display device 100. The display area AA may include a plurality of sub-pixels SP constituting a plurality of pixels PX and a pixel circuit configured to operate the plurality of sub-pixels SP. The plurality of sub-pixels SP are the smallest units constituting the display area AA. n sub-pixels SP may constitute a single pixel PX. Thin film transistors and the like for operating a plurality of light-emitting elements LED may be respectively provided in the plurality of sub-pixels SP. The plurality of light-emitting elements LED may be differently defined according to the type of the display panel PN. For example, in the case where the display panel PN is an inorganic light-emitting display panel PN, the light-emitting element LED may be a light-emitting diode (LED) or a micro light-emitting diode (micro LED).

[0056] A plurality of signal lines for transmitting various types of signals to the plurality of sub-pixels SP are provided in the display area AA. For example, the plurality of signal lines may include a plurality of data lines DL for supplying data voltages to the plurality of sub-pixels SP and a plurality of scan lines SL for supplying scan signals to the plurality of sub-pixels SP. The plurality of scan lines SL may extend in one direction in the display area AA and be connected to the plurality of sub-pixels SP. The plurality of data lines DL may extend in a direction different from one direction in the display area AA and be connected to the plurality of sub-pixels SP. In addition, a low potential power line, a high potential power line, etc. may also be provided in the display area AA. However, the present disclosure is not limited thereto.

[0057] The non-display area NA may be defined as an area where no image is displayed, that is, an area extending from the display area AA. The non-display area NA may include link lines and pad electrodes for transmitting signals to the sub-pixels SP in the display area AA. Alternatively, the non-display area NA may include a driving IC, such as a gate driver IC and a data driver IC.

[0058] Meanwhile, the non-display area NA may be located on the rear of the display panel PN, ie, on the surface where the sub-pixel SP does not exist. Alternatively, the non-display area NA may not be included. However, the present disclosure is not limited to the configurations shown in the drawings.

[0059] Meanwhile, driving parts such as the gate driving part GD, the data driving part DD, and the timing controller TC may be connected to the display panel PN in various ways. For example, the gate driving part GD may be installed in the non-display area NA by a gate-in-panel (GIP) method, or may be installed between a plurality of sub-pixels SP in the display area AA by a gate-in-active-area (GIA) method.

[0060] For example, the data driving part DD and the timing controller TC may be formed on separate flexible films and printed circuit boards, and the display panel PN, the data driving part DD, and the timing controller TC may be electrically connected by bonding the flexible film and the printed circuit board to pad electrodes formed in the non-display area NA of the display panel PN.

[0061] As another example, in the case where the gate driving part GD is installed in the display area AA by the GIA method and a side line SRL is formed to connect the signal line on the front of the display panel PN to the pad electrode on the rear of the display panel PN to bond the flexible film and the printed circuit board to the rear of the display panel PN, the non-display area NA on the front of the display panel PN can be minimized. Therefore, in the case where the gate driving part GD, the data driving part DD and the timing controller TC are connected to the display panel PN by the above method, a zero frame in which there is substantially no frame can be achieved. Referring to Figure 2A and Figure 2B Description A more detailed description.

[0062] Figure 2A is a partial cross-sectional view of a display device according to an embodiment of the present disclosure. Figure 2B is a perspective view of a tiled display device according to an embodiment of the present disclosure.

[0063] A plurality of pad electrodes for transmitting various types of signals to a plurality of sub-pixels SP are provided in the non-display area NA of the display panel PN. For example, a first pad electrode PAD1 configured to transmit signals to a plurality of sub-pixels SP is provided in the non-display area NA on the front of the display panel PN. A second pad electrode PAD2 electrically connected to a driving component such as a flexible film and a printed circuit board is provided in the non-display area NA on the rear of the display panel PN.

[0064] In this case, although not shown in the drawings, various types of signal lines such as scan lines SL, data lines DL, etc. connected to the plurality of sub-pixels SP may extend from the display area AA to the non-display area NA and be electrically connected to the first pad electrode PAD1.

[0065] In addition, the side line SRL is disposed along the side of the display panel PN. The side line SRL may electrically connect the first pad electrode PAD1 on the front of the display panel PN and the second pad electrode PAD2 on the rear of the display panel PN. Therefore, a signal received from a driving component on the rear of the display panel PN may be transmitted to a plurality of sub-pixels SP through the second pad electrode PAD2, the side line SRL, and the first pad electrode PAD1. Therefore, a signal transmission path is defined from the front to the side and rear of the display panel PN, which may minimize the area of ​​the non-display region NA on the front of the display panel PN.

[0066] In addition, refer to Figure 2B , a tiled display device TD having a large screen can be realized by connecting a plurality of display devices 100. In this case, Figure 2A As shown, in the case of implementing the tiled display device TD by using the display device 100 with a minimized frame, a seam area between the display devices 100 where no image is displayed may be minimized, thereby improving display quality.

[0067] For example, a plurality of sub-pixels SP may constitute a single pixel PX. An interval D1 between the outermost pixel PX of one display device 100 and the outermost pixel PX of another display device 100 adjacent to the one display device 100 may be implemented to be equal to an interval D1 between pixels PX in one display device 100. Therefore, when a constant interval of pixels PX is implemented between display devices 100 and display devices 100, a seam area may be minimized.

[0068] However, if Figure 2A and Figure 2B As shown, the display device 100 according to the embodiment of the present disclosure may be a general display device having a frame. However, the present disclosure is not limited thereto.

[0069] In the following, reference will be made to Figure 3 and Figure 4 The sub-pixel SP of the display panel PN of the display device 100 according to the embodiment of the present disclosure is described in more detail.

[0070] Figure 3 is a schematic enlarged top view of a sub-pixel of a display device according to an embodiment of the present disclosure. Figure 4 is a cross-sectional view of a sub-pixel of a display device according to an embodiment of the present disclosure. For ease of description, Figure 3 Only the first LED, the second LED and the first connection electrode CE1 are shown.

[0071] Reference Figure 3 and Figure 4 The display panel of the display device 100 according to the embodiment of the present disclosure includes a substrate 110, a buffer layer 111, a gate insulating layer 112, a first interlayer insulating layer 113, a second interlayer insulating layer 114, a first planarizing layer 116a, a second planarizing layer 116b, and a third planarizing layer 116c. In addition, each of the plurality of sub-pixels SP includes a driving transistor DT, a power line VL, an intermediate electrode CNT, a first reflective electrode RE1, a second reflective electrode RE2, a first connection electrode CE1, a second connection electrode CE2, a first bonding layer BD1, a second bonding layer BD2, a first light emitting element 120, and a second light emitting element 130.

[0072] First, the substrate 110 may be an insulating substrate supporting components provided on the display device 100. For example, the substrate 110 may be made of glass, resin, etc. In addition, the substrate 110 may be made of polymer, plastic, etc. In some embodiments, the substrate 110 may be made of a plastic material having flexibility. A plurality of pixels PX each including a plurality of sub-pixels SP may be formed on the substrate 110 to display an image.

[0073] A light blocking layer BSM is provided on the substrate 110. The light blocking layer BSM may block light entering the active layer ACT of the driving transistor DT, thereby minimizing leakage current. For example, the light blocking layer BSM may be provided below the active layer ACT of the driving transistor DT, and block light entering the active layer ACT. If light is emitted to the active layer ACT, leakage current occurs, which may deteriorate the reliability of the driving transistor DT. Therefore, a light blocking layer BSM for blocking light may be provided on the substrate 110, thereby improving the reliability of the driving transistor DT. The light blocking layer BSM may be made of an opaque conductive material such as copper (Cu), aluminum (Al), molybdenum (Mo), nickel (Ni), titanium (Ti), chromium (Cr) or an alloy thereof. However, the present disclosure is not limited thereto.

[0074] A buffer layer 111 is disposed on the light blocking layer BSM and the substrate 110. The buffer layer 111 may be disposed to cover one surface of the substrate 110 and reduce the penetration of moisture or impurities through the substrate 110. For example, the buffer layer 111 may be configured as a single layer or multiple layers made of silicon oxide (SiOx) or silicon nitride (SiNx). However, the present disclosure is not limited thereto. The buffer layer 111 may not be included depending on the type of the substrate 110, the type of the transistor, etc. However, the present disclosure is not limited thereto.

[0075] Meanwhile, although not shown in the drawings, an additional buffer layer may be further provided between the substrate 110 and the light blocking layer BSM. Like the buffer layer 111, the additional buffer layer may be provided to reduce the penetration of moisture or impurities through the substrate 110. For example, the additional buffer layer may be configured as a single layer or multiple layers made of silicon oxide (SiOx) or silicon nitride (SiNx). However, the present disclosure is not limited thereto.

[0076] Next, a driving transistor DT is disposed on the buffer layer 111. The driving transistor DT includes an active layer ACT, a gate electrode GE, a source electrode SE, and a drain electrode DE. Meanwhile, although not shown in the drawings, in addition to the driving transistor DT, other transistors such as a switching transistor, a sensing transistor, and a light emission control transistor may be additionally disposed in each of the plurality of sub-pixels SP.

[0077] First, an active layer ACT of a driving transistor DT is disposed on the buffer layer 111. The active layer ACT may be disposed to overlap with the light blocking layer BSM. The active layer ACT may be made of a semiconductor material such as an oxide semiconductor, amorphous silicon, or polycrystalline silicon. However, the present disclosure is not limited thereto. In addition, although not shown in the drawings, the active layers of other transistors such as a switching transistor, a sensing transistor, and a light emitting control transistor may each be made of a semiconductor material such as an oxide semiconductor, amorphous silicon, or polycrystalline silicon. However, the present disclosure is not limited thereto. In addition, the active layers ACT of the driving transistor DT, the switching transistor, the sensing transistor, and the light emitting control transistor may be made of the same material or different materials.

[0078] A gate insulating layer 112 is disposed on the active layer ACT. The gate insulating layer 112 is an insulating layer for insulating the active layer ACT and the gate electrode GE. For example, the gate insulating layer 112 may be configured as a single layer or multiple layers made of silicon oxide (SiOx) or silicon nitride (SiNx). However, the present disclosure is not limited thereto.

[0079] The gate electrode GE is disposed on the gate insulating layer 112. The gate electrode GE may be disposed to overlap the active layer ACT. The gate electrode GE may be made of a conductive material such as copper (Cu), aluminum (Al), molybdenum (Mo), nickel (Ni), titanium (Ti), chromium (Cr), or an alloy thereof. However, the present disclosure is not limited thereto.

[0080] A first interlayer insulating layer 113 and a second interlayer insulating layer 114 are disposed on the gate electrode GE. Contact holes are formed in the first interlayer insulating layer 113 and the second interlayer insulating layer 114, and the source electrode SE and the drain electrode DE are connected to the active layer ACT through the contact holes. The first interlayer insulating layer 113 and the second interlayer insulating layer 114 are insulating layers for protecting components disposed under the first interlayer insulating layer 113 and the second interlayer insulating layer 114. The first interlayer insulating layer 113 and the second interlayer insulating layer 114 may each be configured as a single layer or a multilayer made of silicon oxide (SiOx) or silicon nitride (SiNx). However, the present disclosure is not limited thereto.

[0081] The source electrode SE and the drain electrode DE are disposed on the second interlayer insulating layer 114. The source electrode SE and the drain electrode DE may be electrically connected to the active layer ACT through contact holes formed in the first interlayer insulating layer 113 and the second interlayer insulating layer 114. In addition, the source electrode SE may be electrically connected to the light blocking layer BSM through the intermediate electrode CNT. The drain electrode DE may be electrically connected to the first light emitting element 120 and the second light emitting element 130 through the first reflective electrode RE1 to be described below. The source electrode SE and the drain electrode DE may each be made of a conductive material such as copper (Cu), aluminum (Al), molybdenum (Mo), nickel (Ni), titanium (Ti), chromium (Cr) or an alloy thereof. However, the present disclosure is not limited thereto.

[0082] The intermediate electrode CNT is disposed between the gate insulating layer 112 and the first interlayer insulating layer 113. The intermediate electrode CNT is configured to electrically connect the source electrode SE and the light blocking layer BSM. The intermediate electrode CNT may be made of the same conductive material as the gate electrode GE. For example, the intermediate electrode CNT may be made of copper (Cu), aluminum (Al), molybdenum (Mo), nickel (Ni), titanium (Ti), chromium (Cr) or an alloy thereof. However, the present disclosure is not limited thereto.

[0083] The power line VL is disposed on the second interlayer insulating layer 114. The power line VL may be made of the same conductive material as the source electrode SE and the drain electrode DE. For example, the power line VL may be made of copper (Cu), aluminum (Al), molybdenum (Mo), nickel (Ni), titanium (Ti), chromium (Cr) or an alloy thereof. However, the present disclosure is not limited thereto. The power line VL may be electrically connected to the first light emitting element 120 and the second light emitting element 130 via the second reflective electrode RE2 to be described below. Depending on the configuration of the pixel circuit, the power line VL may be configured as either a low potential power line VL or a high potential power line VL.

[0084] A passivation layer 115 is disposed on the driving transistor DT and the power line VL. The passivation layer 115 is an insulating layer for protecting components disposed below the passivation layer 115. The passivation layer 115 may be configured as a single layer or multiple layers made of an inorganic material such as silicon oxide (SiOx) or silicon nitride (SiNx). However, the present disclosure is not limited thereto.

[0085] A first planarization layer 116a is disposed on the passivation layer 115. The first planarization layer 116a may planarize the upper portion of the pixel circuit including the driving transistor DT. The first planarization layer 116a may be configured as a single layer or multiple layers and made of, for example, benzocyclobutene or an acrylic-based organic material. However, the present disclosure is not limited thereto.

[0086] A plurality of reflective electrodes are disposed on the first planarization layer 116a. The plurality of reflective electrodes may be used to reflect light emitted from the plurality of light emitting elements LED toward the upper side of the substrate 110. At the same time, the plurality of reflective electrodes may be used as electrodes electrically connecting the plurality of light emitting elements LED, the driving transistor DT, and the power line VL. The plurality of reflective electrodes include a first reflective electrode RE1 and a second reflective electrode RE2 disposed in each of the plurality of sub-pixels SP.

[0087] The first reflective electrode RE1 is disposed on the first planarization layer 116a. The first reflective electrode RE1 may be used to reflect light emitted from the plurality of light emitting elements LED toward the upper side of the substrate 110. At the same time, the first reflective electrode RE1 may be used as an electrode electrically connecting the plurality of light emitting elements LED and the power line VL. For example, the first reflective electrode RE1 may be electrically connected to the power line VL through a contact hole formed in the first planarization layer 116a and the passivation layer 115. The first reflective electrode RE1 may be electrically connected to a first electrode of each of the plurality of light emitting elements LED through a first connection electrode CE1 to be described below.

[0088] The second reflective electrode RE2 is disposed on the first planarization layer 116a. The second reflective electrode RE2 may be disposed to overlap with the plurality of light emitting elements LED, and reflect light emitted from the plurality of light emitting elements LED toward the upper side of the substrate 110. In addition, the second reflective electrode RE2 may be used as an electrode electrically connecting the plurality of light emitting elements LED and the driving transistor DT. For example, the second reflective electrode RE2 may be electrically connected to the drain electrode DE of the driving transistor DT through a contact hole formed in the first planarization layer 116a and the passivation layer 115. In addition, the second reflective electrode RE2 may be electrically connected to the second electrode of each of the plurality of light emitting elements LED.

[0089] Therefore, considering the light reflection efficiency and resistance, the plurality of reflective electrodes may include various conductive layers. For example, the plurality of reflective electrodes may be manufactured by using an opaque conductive layer made of silver (Ag), aluminum (Al), molybdenum (Mo), titanium (Ti) or an alloy thereof together with a transparent conductive layer made of indium tin oxide (ITO). However, the structure of the plurality of reflective electrodes is not limited thereto.

[0090] A first bonding layer BD1 is provided on the second reflective electrode RE2. The first bonding layer BD1 may be a conductive connecting member configured to electrically connect the first light emitting element 120 and the second reflective electrode RE2 while fixing the first light emitting element 120 to the second reflective electrode RE2. The first bonding layer BD1 may have conductivity to electrically connect the second reflective electrode RE2 and the first light emitting element 120. In addition, the first bonding layer BD1 may have bonding properties to fix the first light emitting element 120 to the second reflective electrode RE2. For example, the first bonding layer BD1 may be a bonding layer including conductive particles or an anisotropic conductive film (ACF). However, the present disclosure is not limited thereto. As another example, in the case where the first light emitting element 120 is bonded to the first bonding layer BD1 by thermocompression bonding, the first bonding layer BD1 may be made of a eutectic metal. For example, the first bonding layer BD1 may be made of tin (Sn), indium (In), zinc (Zn), lead (Pb), nickel (Ni), gold (Au), platinum (Pt), copper (Cu), etc. However, the present disclosure is not limited thereto.

[0091] A plurality of light emitting elements LED are disposed on the first planarization layer 116a and the second reflective electrode RE2. The plurality of light emitting elements LED include a first light emitting element 120 and a second light emitting element 130 disposed in each of the plurality of sub-pixels SP. The first light emitting element 120 and the second light emitting element 130 disposed in the same sub-pixel SP may emit light having the same color. The first light emitting element 120 and the second light emitting element 130 may be stacked vertically. The second light emitting element 130 may be disposed on the first light emitting element 120. In this case, the first light emitting element 120 on which the second light emitting element 130 is disposed may have a larger size than the second light emitting element 130. Therefore, the first light emitting element 120 has a relatively large size, so that the second light emitting element 130 may be more easily aligned and disposed on the first light emitting element 120.

[0092] The first light emitting element 120 and the second light emitting element 130 may be vertical light emitting element LEDs (vertical chips) in which electrodes are arranged in an upward / downward direction with a light emitting layer interposed between the electrodes. For example, the first light emitting element 120 and the second light emitting element 130 may each be configured such that an n-type electrode and a p-type electrode may be arranged above or below the light emitting layer.

[0093] In this case, the first light-emitting element 120 and the second light-emitting element 130 may be arranged so that the arrangement directions of the electrodes are opposite to each other. For example, the first light-emitting element 120 may be arranged so that the first n-type electrode 124 is arranged above the first light-emitting layer 122. The second light-emitting element 130 may be arranged so that the second n-type electrode 134 is arranged below the second light-emitting layer 132. Therefore, the first light-emitting element 120 and the second light-emitting element 130 may be arranged to be horizontally symmetrical.

[0094] The first light emitting element 120 is disposed on the first bonding layer BD1 and includes a first n-type semiconductor layer 121 , a first light emitting layer 122 , a first p-type semiconductor layer 123 , a first n-type electrode 124 , a first p-type electrode 125 , and a first protective film 126 .

[0095] The first p-type semiconductor layer 123 is disposed on the first bonding layer BD1, and the first n-type semiconductor layer 121 is disposed on the first p-type semiconductor layer 123. The first n-type semiconductor layer 121 and the first p-type semiconductor layer 123 may each be a layer formed by doping a specific material with n-type and p-type impurities. For example, the first n-type semiconductor layer 121 and the first p-type semiconductor layer 123 may each be a layer formed by doping a material such as gallium nitride (GaN), indium aluminum phosphide (InAlP), or gallium arsenide (GaAs) with n-type or p-type impurities. The n-type impurity may be silicon (Si), germanium Ge, tin (Sn), etc. The p-type impurity may be magnesium (Mg), zinc (Zn), beryllium (Be), etc. However, the present disclosure is not limited thereto.

[0096] The first light emitting layer 122 is disposed between the first p-type semiconductor layer 123 and the first n-type semiconductor layer 121. The first light emitting layer 122 may emit light by receiving positive holes and electrons from the first p-type semiconductor layer 123 and the first n-type semiconductor layer 121. The first light emitting layer 122 may be configured as a single layer or a multi-quantum well (MQW) structure. For example, the first light emitting layer 122 may be made of indium gallium nitride (InGaN), gallium nitride (GaN), etc. However, the present disclosure is not limited thereto.

[0097] The first p-type electrode 125 is disposed on the bottom surface of the first p-type semiconductor layer 123. The first p-type electrode 125 may be adjacent to the first bonding layer BD1. The first p-type electrode 125 may be electrically connected to the second reflective electrode RE2 through the first bonding layer BD1. Therefore, the first p-type semiconductor layer 123 may be electrically connected to the driving transistor DT through the first p-type electrode 125, the first bonding layer BD1, and the second reflective electrode RE2. The first p-type electrode 125 may be made of an opaque conductive material with high reflection efficiency such as titanium (Ti), gold (Au), silver (Ag), copper (Cu), or an alloy thereof, and / or a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). However, the present disclosure is not limited thereto.

[0098] The first n-type electrode 124 is disposed on the top surface of the first n-type semiconductor layer 121. The first n-type electrode 124 may be disposed to cover the entire top surface of the first n-type semiconductor layer 121. The first n-type electrode 124 is an electrode that electrically connects the first n-type semiconductor layer 121, the first connection electrode CE1, the first reflective electrode RE1, and the power line VL. For example, the first n-type semiconductor layer 121 may be made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). However, the present disclosure is not limited thereto.

[0099] The first protective film 126 is provided to surround the first n-type semiconductor layer 121, the first light emitting layer 122, and the first p-type semiconductor layer 123. The first protective film 126 may be made of an insulating material and protect the first n-type semiconductor layer 121, the first light emitting layer 122, and the first p-type semiconductor layer 123. The first protective film 126 is provided to cover a portion of the side surface of the first n-type semiconductor layer 121, a portion of the side surface of the first light emitting layer 122, a portion of the side surface of the first p-type semiconductor layer 123, and a portion of the bottom surface of the first p-type semiconductor layer 123. In this case, the first p-type electrode 125 may be exposed from the first protective film 126 and abut the first bonding layer BD1. Therefore, the first protective film 126 may be formed to cover at least a portion of the first n-type semiconductor layer 121, at least a portion of the first light emitting layer 122, and at least a portion of the first p-type semiconductor layer 123, thereby suppressing short-circuit defects and minimizing damage to the first n-type semiconductor layer 121, the first light emitting layer 122, and the first p-type semiconductor layer 123. The first protective film 126 may be made of any one of a silicon oxide (SiOx)-based material, a silicon nitride (SiNx)-based material, and a resin. However, the present disclosure is not limited thereto.

[0100] The second planarization layer 116b is disposed on the first light emitting element 120 and the first planarization layer 116a. The second planarization layer 116b may planarize the upper portion of the substrate 110 on which the first light emitting element 120 is disposed. The second planarization layer 116b may be disposed to cover at least a portion of the first light emitting element 120 and suppress defects such as the first connection electrode CE1 being connected to the first p-type semiconductor layer 123. The second planarization layer 116b may be configured as a single layer or a multilayer and made of, for example, a benzocyclobutene or acrylic-based organic material. However, the present disclosure is not limited thereto.

[0101] The first connection electrode CE1 is disposed on the second planarization layer 116b. The first connection electrode CE1 may be electrically connected to the first reflective electrode RE1 through a contact hole formed in the second planarization layer 116b. The first connection electrode CE1 may be disposed to cover a portion of the first light emitting element 120 and to abut against the first n-type electrode 124 of the first light emitting element 120. Therefore, the first n-type semiconductor layer 121 and the first n-type electrode 124 of the first light emitting element 120 may be electrically connected to the power line VL through the first connection electrode CE1 and the first reflective electrode RE1. The first connection electrode CE1 may be made of an opaque conductive material such as titanium (Ti), gold (Au), silver (Ag), copper (Cu), or an alloy thereof to reflect light emitted from the second light emitting element 130 disposed on the first connection electrode CE1 toward the upper side of the substrate 110. Therefore, the first connection electrode CE1 may serve as a reflective plate to allow light from the second light emitting element 130 to propagate toward the outside of the display device 100.

[0102] In this case, in order to allow light emitted from the first light emitting element 120 disposed under the first connection electrode CE1 to propagate toward the upper side of the substrate 110, the first connection electrode CE1 may be disposed to cover only at least a portion of the first light emitting element 120. For example, the planar shape of the first connection electrode CE1 may be a cross shape so that the first connection electrode CE1 may overlap only a portion of the first light emitting element 120. Therefore, a portion of the light from the first light emitting element 120 may propagate toward the upper side of the substrate 110 through a region where the first connection electrode CE1 is not disposed.

[0103] Meanwhile, another portion of the light from the first light emitting element 120 may be reflected by the first connection electrode CE1 toward the lower side of the substrate 110. However, the light may be reflected again by the second reflective electrode RE2 disposed below the first light emitting element 120 and propagate toward the upper side of the substrate 110. Therefore, a portion of the light emitted from the first light emitting element 120 may be reflected between the first connection electrode CE1 and the second reflective electrode RE2 and propagate toward the upper side of the substrate 110. In addition, the light emitted from the first light emitting element 120 may be dispersed in the left / right direction while propagating between the first connection electrode CE1 and the second reflective electrode RE2, which may improve the optical viewing angle and brightness in the lateral direction of the display device 100.

[0104] The second bonding layer BD2 is disposed on the first connection electrode CE1. The second bonding layer BD2 may be a conductive connecting member that fixes the second light emitting element 130 to the first connection electrode CE1 and electrically connects the second light emitting element 130 and the first connection electrode CE1. The second bonding layer BD2 may be disposed to overlap with the first light emitting element 120. The second bonding layer BD2 may have conductivity to electrically connect the first connection electrode CE1 and the second light emitting element 130. The second bonding layer BD2 may have bonding properties to fix the second light emitting element 130 to the first connection electrode CE1. In addition, the second bonding layer BD2 overlapping the first light emitting element 120 may have a high transmittance so that the light from the first light emitting element 120 propagates toward the upper side of the substrate 110. For example, the second bonding layer BD2 may be a bonding layer including conductive particles or an anisotropic conductive film (ACF). However, the present disclosure is not limited thereto.

[0105] The second light emitting element 130 is disposed on the second bonding layer BD2 and includes a second n-type semiconductor layer 131 , a second light emitting layer 132 , a second p-type semiconductor layer 133 , a second n-type electrode 134 , a second p-type electrode 135 , and a second protective film 136 .

[0106] The second n-type semiconductor layer 131 is disposed on the second bonding layer BD2, and the second p-type semiconductor layer 133 is disposed on the second n-type semiconductor layer 131. The second n-type semiconductor layer 131 and the second p-type semiconductor layer 133 may each be a layer formed by doping a specific material with n-type and p-type impurities. For example, the second n-type semiconductor layer 131 and the second p-type semiconductor layer 133 may each be a layer formed by doping a material such as gallium nitride (GaN), indium aluminum phosphide (InAlP), or gallium arsenide (GaAs) with n-type or p-type impurities. The n-type impurity may be silicon (Si), germanium Ge, tin (Sn), etc. The p-type impurity may be magnesium (Mg), zinc (Zn), beryllium (Be), etc. However, the present disclosure is not limited thereto.

[0107] The second light emitting layer 132 is disposed between the second p-type semiconductor layer 133 and the second n-type semiconductor layer 131. The second light emitting layer 132 can emit light by receiving positive holes and electrons from the second p-type semiconductor layer 133 and the second n-type semiconductor layer 131. The second light emitting layer 132 can be configured as a single layer or a multi-quantum well (MQW) structure. For example, the second light emitting layer 132 can be made of indium gallium nitride (InGaN), gallium nitride (GaN), etc. However, the present disclosure is not limited thereto.

[0108] The second p-type electrode 135 is disposed on the top surface of the second p-type semiconductor layer 133. The second p-type electrode 135 may be adjacent to the second connection electrode CE2. The second p-type electrode 135 may be electrically connected to the second reflective electrode RE2 through the second connection electrode CE2. Therefore, the second p-type semiconductor layer 133 may be electrically connected to the driving transistor DT through the second p-type electrode 135, the second connection electrode CE2, and the second reflective electrode RE2. The second p-type electrode 135 may be made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). However, the present disclosure is not limited thereto.

[0109] The second n-type electrode 134 is disposed on the bottom surface of the second n-type semiconductor layer 131. The second n-type electrode 134 may be disposed to cover the entire bottom surface of the second n-type semiconductor layer 131. The second n-type electrode 134 is an electrode that electrically connects the second n-type semiconductor layer 131, the first connection electrode CE1, the first reflective electrode RE1, and the power line VL. For example, the second n-type semiconductor layer 131 may be made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). However, the present disclosure is not limited thereto.

[0110] The second protective film 136 is provided to surround the second n-type semiconductor layer 131, the second light emitting layer 132, and the second p-type semiconductor layer 133. The second protective film 136 may be made of an insulating material and protect the second n-type semiconductor layer 131, the second light emitting layer 132, and the second p-type semiconductor layer 133. The second protective film 136 is provided to cover a portion of the side surface of the second n-type semiconductor layer 131, a portion of the side surface of the second light emitting layer 132, a portion of the side surface of the second p-type semiconductor layer 133, and a portion of the top surface of the second p-type semiconductor layer 133. In this case, the second p-type electrode 135 may be exposed from the second protective film 136 and abut the second connection electrode CE2. Therefore, the second protective film 136 may be formed to cover at least a portion of the second n-type semiconductor layer 131, at least a portion of the second light emitting layer 132, and at least a portion of the second p-type semiconductor layer 133, thereby suppressing short-circuit defects and minimizing damage to the second n-type semiconductor layer 131, the second light emitting layer 132, and the second p-type semiconductor layer 133. The second protective film 136 may be made of any one of a silicon oxide (SiOx)-based material, a silicon nitride (SiNx)-based material, and a resin. However, the present disclosure is not limited thereto.

[0111] The third planarization layer 116c is disposed on the second light emitting element 130, the first connection electrode CE1, and the second planarization layer 116b. The third planarization layer 116c may planarize the upper portion of the substrate 110 on which the second light emitting element 130 is disposed. The third planarization layer 116c may be disposed to cover at least a portion of the second light emitting element 130 and suppress defects such as the second connection electrode CE2 being connected to the second n-type semiconductor layer 131. The third planarization layer 116c may be configured as a single layer or a multilayer and made of, for example, a benzocyclobutene or acrylic-based organic material. However, the present disclosure is not limited thereto.

[0112] The second connection electrode CE2 is disposed on the third planarization layer 116c. The second connection electrode CE2 may be electrically connected to the second reflective electrode RE2 through a contact hole formed in the third planarization layer 116c and the second planarization layer 116b. The second connection electrode CE2 may be disposed to cover the second light emitting element 130 and to abut against the second p-type electrode 135 of the second light emitting element 130. Therefore, the second p-type semiconductor layer 133 and the second p-type electrode 135 of the second light emitting element 130 may be electrically connected to the driving transistor DT through the second connection electrode CE2 and the second reflective electrode RE2. The second connection electrode CE2 may be made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) to allow light emitted from the first light emitting element 120 and the second light emitting element 130 to propagate toward the upper side of the substrate 110. However, the present disclosure is not limited thereto.

[0113] Light emitted from the second light emitting element 130 may be reflected by the first connection electrode CE1 made of a material having high reflection efficiency toward the upper side of the substrate 110. Light emitted from the second light emitting element 130 may propagate toward the outside of the display device 100 through the first connection electrode CE1 serving as a reflection plate. In this case, a separate reflection plate is not provided above the second light emitting element 130, but only the second connection electrode CE2 made of a transparent conductive material is provided above the second light emitting element 130, so that light may easily propagate toward the upper side of the second light emitting element 130. Therefore, light emitted from the second light emitting element 130 may propagate toward the upper side of the second light emitting element 130, which may improve brightness in the forward direction of the display device 100.

[0114] At the same time, the first n-type electrode 124 of the first light emitting element 120 and the second n-type electrode 134 of the second light emitting element 130 can be electrically connected to the power line VL through the first connection electrode CE1 and the first reflective electrode RE1. In addition, the first p-type electrode 125 of the first light emitting element 120 can be electrically connected to the driving transistor DT through the first bonding layer BD1 and the second reflective electrode RE2. The second p-type electrode 135 of the second light emitting element 130 can also be electrically connected to the driving transistor DT through the second connection electrode CE2 and the second reflective electrode RE2. Therefore, a plurality of light emitting elements LED can be connected in parallel so that the n-type electrodes can be electrically connected to the power line VL together, and the p-type electrodes can be electrically connected to the driving transistor DT together. In a state where the first light emitting element 120 and the second light emitting element 130 are connected in parallel, when the display device 100 is operating, the first light emitting element 120 and the second light emitting element 130 can work together. Therefore, even if a defect occurs on any one of the first light emitting element 120 and the second light emitting element 130 connected in parallel, the remaining light emitting element LED can emit light, and the sub-pixel SP can operate normally.

[0115] In addition, in the present disclosure, a configuration has been described in which the first n-type semiconductor layer 121 and the first n-type electrode 124 of the first light-emitting element 120 are arranged above the first light-emitting layer 122, and the second p-type semiconductor layer 133 and the second p-type electrode 135 of the second light-emitting element 130 are arranged above the second light-emitting layer 132. However, the arrangement directions of the two light-emitting elements LED may be opposite to each other. However, the present disclosure is not limited to this. For example, the first light-emitting element 120 may be arranged so that the first p-type semiconductor layer 123 and the first p-type electrode 125 are located above the first light-emitting layer 122, and the second light-emitting element 130 may be arranged so that the second n-type semiconductor layer 131 and the second n-type electrode 134 are located above the second light-emitting layer 132. In this case, the first p-type semiconductor layer 123, the first p-type electrode 125, the second p-type semiconductor layer 133 and the second p-type electrode 135 can be electrically connected to the first connection electrode CE1 and the power line VL, and the first n-type semiconductor layer 121, the first n-type electrode 124, the second n-type semiconductor layer 131 and the second n-type electrode 134 can be electrically connected to the driving transistor DT.

[0116] Therefore, in the display device 100 according to the embodiment of the present disclosure, the first light emitting element 120 and the second light emitting element 130 which are vertically stacked and connected in parallel are arranged in each of the plurality of sub-pixels SP, thereby minimizing the defects of the sub-pixels SP. The first light emitting element 120 and the second light emitting element 130 which define the vertical structure can be vertically stacked so that the first n-type semiconductor layer 121 and the second n-type semiconductor layer 131 face each other. The first n-type semiconductor layer 121 and the second n-type semiconductor layer 131 can be electrically connected to the power line VL together through the first connection electrode CE1. In addition, the first p-type semiconductor layer 123 of the first light emitting element 120 and the second p-type semiconductor layer 133 of the second light emitting element 130 can also be electrically connected to the driving transistor DT together through the first bonding layer BD1 or the second connection electrode CE2. The first light emitting element 120 and the second light emitting element 130 can be connected in parallel to the pixel circuit and work together. Therefore, even if one of the two light emitting elements LED is defective, the remaining light emitting element LED can emit light normally. Therefore, a plurality of light emitting elements LED may be provided in each of the plurality of sub-pixels SP, which may prepare for defects of a portion of the light emitting elements LED and improve reliability and display quality of the display device 100 .

[0117] In the display device 100 according to the embodiment of the present disclosure, the first light-emitting element 120 and the second light-emitting element 130 are stacked vertically, which can reduce the area of ​​the sub-pixel SP. If the first light-emitting element 120 and the second light-emitting element 130 are arranged horizontally, it is necessary to ensure both the area where the first light-emitting element 120 is arranged and the area where the second light-emitting element 130 is arranged, which may increase the area required for multiple sub-pixels SP. Therefore, in the display device 100 according to the embodiment of the present disclosure, the second light-emitting element 130 can be arranged above the first light-emitting element 120, so that the area where the first light-emitting element 120 is arranged and the area where the second light-emitting element 130 is arranged can be integrated into a single area, which can reduce the area required for multiple sub-pixels SP. Therefore, more sub-pixels SP can be formed in the display device 100, and a display device 100 capable of displaying high-resolution images can be realized.

[0118] In this case, the size of the first light emitting element 120 may be larger than that of the second light emitting element 130, so that the second light emitting element 130 may be more easily aligned and disposed on the first light emitting element 120. If the size of the first light emitting element 120 is equal to or smaller than that of the second light emitting element 130, it may be difficult to align the second light emitting element 130 correspondingly with the first light emitting element 120. Therefore, the first light emitting element 120 may have a relatively large size, so that the second light emitting element 130 may be easily aligned and disposed in a region in which the first light emitting element 120 is disposed.

[0119] In the display device 100 according to the embodiment of the present disclosure, the first connection electrode CE1 made of a material having high reflection efficiency is formed between the first light emitting element 120 and the second light emitting element 130, and partially overlaps the first light emitting element 120 and the second light emitting element 130, which can improve the optical viewing angle and brightness in the forward direction and the lateral direction of the display device 100. The first light emitting element 120 disposed under the first connection electrode CE1 can improve the viewing angle and brightness in the lateral direction, and the second light emitting element 130 disposed on the first connection electrode CE1 can improve the brightness in the forward direction. Light from the first light emitting element 120 can be dispersed in the left / right direction while propagating between the first connection electrode CE1 and the second reflective electrode RE2, which can improve the optical viewing angle and brightness in the lateral direction of the display device 100. In addition, light from the second light emitting element 130 can propagate toward the upper side of the substrate 110 by means of the first connection electrode CE1, which can improve the brightness of the display device 100. Therefore, the first light emitting element 120 configured to allow most light to propagate in the left / right direction and the second light emitting element 130 configured to allow light to propagate in the forward direction are disposed together, which can improve the viewing angle characteristics and brightness of the display device 100.

[0120] Figure 5A is a schematic enlarged top view of a sub-pixel of a display device according to another embodiment of the present disclosure. Figure 5B is a schematic enlarged top view of a sub-pixel of a display device according to another embodiment of the present disclosure. In addition to the first connection electrode CE1, Figure 5A and Figure 5B The display devices 500A and 500B in the embodiment are similar in configuration to those in the embodiment of the present invention. Figures 1 to 4 The display device 100 in FIG. 1 is substantially the same as that in FIG. 1 . Therefore, repeated description of the same components will be omitted.

[0121] Reference Figure 5A and Figure 5B , the first connection electrode CE1 includes a plurality of opening portions CE10 configured to allow light emitted from the first light emitting element 120 disposed below the first connection electrode CE1 to propagate toward the outside of the display devices 500A and 500B. The plurality of opening portions CE10 may be disposed to be spaced apart from each other. At least some of the plurality of opening portions CE10 may overlap with the first light emitting element 120. Some of the remaining opening portions CE10 may overlap with an area at the periphery of the first light emitting element 120. A portion of the light from the first light emitting element 120 may propagate toward the upper side of the substrate 110 through the plurality of opening portions CE10.

[0122] The plurality of opening portions CE10 may be formed in various shapes. Figure 5A As shown in FIG. 1 , the plurality of opening portions CE10 may be implemented as a plurality of stripe patterns. Figure 5B As shown, the plurality of opening portions CE10 may be arranged in a plurality of rows and columns. The first link electrode CE1 may be formed in a mesh shape by the plurality of opening portions CE10.

[0123] The first light emitting element 120 and the second light emitting element 130 may be electrically connected to the first connection electrode CE1 while being adjacent to a portion of the first connection electrode CE1 disposed between the plurality of opening portions CE10. Therefore, the plurality of opening portions CE10 may be disposed in consideration of the contact area of ​​the first light emitting element 120, the second light emitting element 130, and the first connection electrode CE1. For example, as the area of ​​the plurality of opening portions CE10 overlapping the first light emitting element 120 increases, the contact area of ​​the first connection electrode CE1 with the plurality of light emitting elements LED decreases, but the light extraction efficiency of the first light emitting element 120 may be improved. On the contrary, as the area of ​​the plurality of opening portions CE10 overlapping the first light emitting element 120 decreases, the contact area of ​​the first connection electrode CE1 with the plurality of light emitting elements LED increases, but the light extraction efficiency of the first light emitting element 120 may be deteriorated. Therefore, the size and position of the plurality of opening portions CE10 may be differently designed in consideration of the contact area of ​​the first connection electrode CE1 and the plurality of light emitting elements LED and the light extraction efficiency of the first light emitting element 120.

[0124] Meanwhile, the first connection electrode CE1 having the plurality of opening portions CE1O may be continuously formed without being divided. In the case where the first connection electrode CE1 is divided by the plurality of opening portions CE1O, it may be difficult to normally connect the plurality of light emitting elements LED and the power line VL. Therefore, the plurality of opening portions CE1O may be formed only inside the first connection electrode CE1, or may extend only from the edge of the first connection electrode CE1 to a portion of the inner side of the first connection electrode CE1.

[0125] In the display devices 500A and 500B according to various embodiments of the present disclosure, a plurality of opening portions CE10 are formed in the first connection electrode CE1 so that light emitted from the first light emitting element 120 can propagate toward the outside of the display devices 500A and 500B. The plurality of opening portions CE10 may be disposed to overlap with a region where the first light emitting element 120 is disposed and a region at the periphery of the first light emitting element 120, and light emitted from the first light emitting element 120 may propagate toward the upper side of the substrate 110 through the plurality of opening portions CE10 of the first connection electrode CE1. The plurality of opening portions CE10 may be differently designed in consideration of the contact area and resistance of the first connection electrode CE1 and the plurality of light emitting elements LED and the light extraction efficiency of the first light emitting element 120. Therefore, a plurality of opening portions CE10 may be formed in the first connection electrode CE1, which may improve the efficiency of extracting light emitted from the first light emitting element 120 and improve the brightness of the display devices 500A and 500B.

[0126] Figure 6 is a schematic enlarged top view of a sub-pixel of a display device according to yet another embodiment of the present disclosure. Figure 7 is a cross-sectional view of a sub-pixel of a display device according to another embodiment of the present disclosure. In addition to the first connection electrode CE1 including a plurality of layers, Figure 6 and Figure 7 The display device 600 in the embodiment is configured similarly to Figures 1 to 4 The display device 100 in FIG. 1 is substantially the same as that in FIG. 1 . Therefore, repeated description of the same components will be omitted.

[0127] Reference Figure 6 and Figure 7 , the first connection electrode CE1 includes a first electrode layer CE1a and a second electrode layer CE1b. The first connection electrode CE1 may have a multi-layer structure, which includes a first electrode layer CE1a and a second electrode layer CE1b disposed on the first electrode layer CE1a. The first electrode layer CE1a of the first connection electrode CE1 may be made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The second electrode layer CE1b may be made of an opaque conductive material with high reflection efficiency such as titanium (Ti), gold (Au), silver (Ag), copper (Cu) or an alloy thereof.

[0128] The first connection electrode CE1 includes a transmission portion CE1P made by patterning a portion of the second electrode layer CE1b. In the transmission portion CE1P, the second electrode layer CE1b may be patterned, and only the first electrode layer CE1a may remain. Therefore, light from the first light emitting element 120 may pass through the transmission portion CE1P provided with only the first electrode layer CE1a made of a transparent conductive material, and propagate toward the outside of the display device 600.

[0129] The transmission portion CE1P may be formed by using a half-tone mask. For example, the first connection electrode CE1 may be formed by sequentially forming a first electrode layer CE1a and a second electrode layer CE1b on the front face of the substrate 110 and etching the first electrode layer CE1a and the second electrode layer CE1b together. In this case, the transmission portion CE1P in which only the first electrode layer CE1a is formed may be formed by using a half-tone mask and additionally etching the second electrode layer CE1b provided in the transmission portion CE1P. Therefore, the half-tone mask may be used to etch only the second electrode layer CE1b on the first electrode layer CE1a in the transmission portion CE1P without etching the first electrode layer CE1a, so that the first electrode layer CE1a remains unchanged.

[0130] The transmission portion CE1P may be designed differently in consideration of the light extraction efficiency or light extraction direction of the first light emitting element 120. Figure 6 As shown, the transmission portion CE1P having a larger size than the first light emitting element 120 in a plan view may be formed to enable light from the first light emitting element 120 to propagate toward the upper side of the substrate 110 .

[0131] In this case, the first connection electrode CE1 has a structure in which the first electrode layer CE1a is completely formed and the second electrode layer CE1b is partially formed in the first electrode layer CE1a. Therefore, even if the second electrode layer CE1b is patterned into various shapes, the power line VL and the light emitting element LED can be easily electrically connected through the first electrode layer CE1a. That is, because the first electrode layer CE1a is used to electrically connect the light emitting element LED and the power line VL, the transmission part CE1P and the second electrode layer CE1b can be formed in various shapes. For example, even if a part of the second electrode layer CE1b is formed into an island shape through the transmission part CE1P, the first electrode layer CE1a can be electrically connected to the second electrode layer CE1b, and the second electrode layer CE1b can be used as an electrode.

[0132] In addition, the second electrode layer CE1b may be disposed on a portion of the remaining first connection electrode CE1 except the transmission portion CE1P and function as a reflection plate that reflects light from the second light emitting element 130 toward the upper side of the substrate 110. Therefore, the second electrode layer CE1b of the first connection electrode CE1 is made of an opaque conductive material having excellent reflection efficiency, which can improve the light extraction efficiency of the second light emitting element 130. The transmission portion CE1P is formed in the second electrode layer CE1b, which can improve the light extraction efficiency of the first light emitting element 120.

[0133] Therefore, in the display device 600 according to still another embodiment of the present disclosure, the first connection electrode CE1 includes a first electrode layer CE1a made of a transparent conductive material and a second electrode layer CE1b made of an opaque conductive material having a high reflection efficiency, and only the second electrode layer CE1b is partially patterned, thereby improving both the light extraction efficiency of the first light emitting element 120 and the light extraction efficiency of the second light emitting element 130. For example, a portion of the second electrode layer CE1b adjacent to the first light emitting element 120 may be patterned so that a transmissive portion CE1P provided with only the first electrode layer CE1a may be formed in the first connection electrode CE1. Light from the first light emitting element 120 may propagate toward the upper side of the substrate 110 through the transmissive portion CE1P. In addition, the remaining second electrode layer CE1b that remains without being patterned may be used as a reflective plate that reflects light emitted from the second light emitting element 130 toward the upper side of the substrate 110. Therefore, the first connection electrode CE1 includes the transparent first electrode layer CE1a and the partially patterned opaque second electrode layer CE1b, which can increase light extraction efficiency of the plurality of light emitting elements LED and improve brightness of the display device 600.

[0134] FIG. 8A to FIG. 9B 800A, 800B, 800C, 800D, 900A, and 900B according to various embodiments of the present disclosure. FIG. 8A to FIG. 9B The display devices 800A, 800B, 800C, 800D, 900A and 900B in FIG. 8 are configured similarly to those in FIG. Figure 6 and Figure 7 The display device 600 in FIG. 1 is substantially the same as that in FIG. 1 . Therefore, repeated description of the same components will be omitted.

[0135] Reference FIG. 8A to FIG. 8D , the first connection electrode CE1 may be disposed to cover the entire first light emitting element 120. In addition, a transmissive portion CE1P having various shapes may be formed in the first connection electrode CE1, which may improve light extraction efficiency of the first light emitting element 120.

[0136] For example, refer to Fig. 8A , the transmission portion CE1P may be formed by patterning a portion of the second electrode layer CE1b overlapping the first light emitting element 120. For example, the transmission portion CE1P having a cross shape may be formed by patterning a portion of the second electrode layer CE1b overlapping the first light emitting element 120 in a cross shape. In this case, light from the first light emitting element 120 may propagate in the upward / downward direction and the leftward / rightward direction.

[0137] In addition, although not shown in the figure, a plurality of transmissive portions CE1P may be formed in the direction in which light is expected to be extracted so that the optical viewing angle characteristics and brightness may be controlled in the corresponding directions. For example, the transmissive portions CE1P are formed in the left and right regions of the first light emitting element 120, which may improve the optical viewing angle characteristics in the left / right direction.

[0138] Reference Figure 8B and Figure 8C , a plurality of transmission portions CE1P may be formed by patterning a portion of the second electrode layer CE1b in a closed loop shape. One of the plurality of transmission portions CE1P may overlap the first light emitting element 120 and be a transmission portion CE1P having a closed loop shape. The rest of the plurality of transmission portions CE1P may be transmission portions CE1P having a closed loop shape and disposed adjacent to the first light emitting element 120. In this case, when the planar shape of the first light emitting element 120 is a quadrilateral shape, the plurality of transmission portions CE1P may have a quadrilateral closed loop shape corresponding to the planar shape of the first light emitting element 120. As another example, the planar shape of the first light emitting element 120 may be a quadrilateral shape, and the plurality of transmission portions CE1P may have a circular closed loop shape. Therefore, the transmission portion CE1P having a closed loop shape is formed in the region overlapping the first light emitting element 120 and the region adjacent to the first light emitting element 120, which may enable light from the first light emitting element 120 to propagate uniformly in all directions.

[0139] Reference Fig.8D , by forming a plurality of transmission parts CE1P in the second electrode layer CE1b, the second electrode layer CE1b may be formed in a grid shape. Some of the plurality of transmission parts CE1P may at least partially overlap with the first light emitting element 120. Some of the remaining transmission parts CE1P may be disposed in an area adjacent to the first light emitting element 120. The plurality of transmission parts CE1P may be disposed in a plurality of rows and columns. The first connection electrode CE1 including the plurality of transmission parts CE1P may be formed in a grid shape. The light extraction efficiency of the first light emitting element 120 may be adjusted by adjusting the sizes of the plurality of transmission parts CE1P. In this case, all the plurality of transmission parts CE1P are described as having the same size. However, the plurality of transmission parts CE1P may have different sizes. However, the present disclosure is not limited thereto.

[0140] Reference Fig.9A and Fig. 9B, the first connection electrode CE1 may be disposed to cover only a portion of the first light emitting element 120. Therefore, light from the first light emitting element 120 may propagate toward the upper side of the substrate 110 through a region where the first connection electrode CE1 is not disposed and through the transmission portion CE1P of the first connection electrode CE1. The first connection electrode CE1 is disposed to cover only a portion of the first light emitting element 120, which may improve light extraction efficiency of the first light emitting element 120.

[0141] For example, refer to Fig.9A , the planar shape of the first connection electrode CE1 is a cross shape, so that the first connection electrode CE1 can be disposed to cover only a portion of the first light emitting element 120. Therefore, the first light emitting element 120 may include a portion overlapping with the first connection electrode CE1 and a portion not overlapping with the first connection electrode CE1. In addition, the second electrode layer CE1b is patterned in a region overlapping with the first light emitting element 120, so that only the first electrode layer CE1a of the first connection electrode CE1 can be disposed on the first light emitting element 120. Therefore, light emitted from the first light emitting element 120 can propagate toward the upper side of the substrate 110 through the transmission portion CE1P of the first connection electrode CE1 and the portion of the first light emitting element 120 not overlapping with the first connection electrode CE1.

[0142] For example, refer to Fig. 9B , a portion of the second electrode layer CE1b that does not overlap the first light emitting element 120 may also be patterned, thereby increasing the area of ​​the plurality of transmission portions CE1P. The plurality of transmission portions CE1P may be additionally formed by partially patterning the second electrode layer CE1b disposed in a portion of the first connection electrode CE1 that does not overlap the first light emitting element 120. Therefore, the plurality of transmission portions CE1P are formed in both the area overlapping the first light emitting element 120 and the area not overlapping the first light emitting element 120, which may improve the light emission efficiency of the first light emitting element 120.

[0143] Therefore, in the display devices 800A, 800B, 800C, 800D, 900A, and 900B according to various embodiments of the present disclosure, the shape of the first connection electrode CE1 and the shapes of the plurality of transmission portions CE1P formed in the first connection electrode CE1 are implemented in different ways, which can improve the light emitting efficiency of the plurality of light emitting elements LED. For example, the transmission portion CE1P formed by patterning the second electrode layer CE1b can be formed in consideration of the size or shape of the first light emitting element 120, the optical viewing angle, and the like. For example, the plurality of transmission portions CE1P are formed in a closed loop shape corresponding to the planar shape of the first light emitting element 120, which can enable the light emitted from the first light emitting element 120 to be uniformly propagated in all directions. In addition, the first connection electrode CE1 is disposed to cover only a portion of the first light emitting element 120, so that the light emitted from the first light emitting element 120 can be more easily extracted to the outside of the display devices 800A, 800B, 800C, 800D, 900A, and 900B.

[0144] Fig.10 is a cross-sectional view of a sub-pixel of a display device according to another embodiment of the present disclosure. In addition to the second planarization layer 1016b, Fig.10 The display device 1000 in the embodiment is configured similarly to Figure 6 and Figure 7 The display device 600 in FIG. 1 is substantially the same as that in FIG. 1 . Therefore, repeated description of the same components will be omitted.

[0145] Reference Fig.10 , the second planarization layer 1016b may be disposed around the first light emitting element 120. The second planarization layer 1016b may include a plurality of light scattering particles PC, which may improve the efficiency of extracting light emitted from the first light emitting element 120. For example, due to the second electrode layer CE1b, a portion of the light emitted from the first light emitting element 120 may not propagate toward the outside of the substrate 110. The light may be scattered by the plurality of light scattering particles PC and propagate in various directions. Therefore, the light may be scattered in various directions by the plurality of light scattering particles PC, which may increase the probability that the light is extracted from the first light emitting element 120 to the transmission portion CE1P where the second electrode layer CE1b is not disposed and the region disposed outside the first connection electrode CE1. For example, the light scattering particles PC may be nanoparticles having a fine size, such as titanium oxide (TiO2), zirconium oxide (ZrO2), and barium titanate (BaTiO3). However, the present disclosure is not limited thereto.

[0146] At the same time, in addition to Figure 6 and Figure 7 In addition to the display device 600 in FIG. 1 , the second planarization layer 1016b including a plurality of light scattering particles PC may also be applied to Figures 1 to 4 The display device 100, Figure 5A and Figure 5B The display devices 500A and 500B, and FIG. 8A to FIG. 9B Display devices 800A, 800B, 800C, 800D, 900A and 900B in.

[0147] Therefore, in the display device 1000 according to another embodiment of the present disclosure, a plurality of light scattering particles PC are disposed in the second planarization layer 1016b surrounding the first light emitting element 120, so that the light from the first light emitting element 120 can be scattered and easily propagated toward the outside of the substrate 110. Due to the second electrode layer CE1b made of an opaque conductive material, a portion of the light from the first light emitting element 120 cannot be emitted toward the outside of the substrate 110. However, this portion of light may be scattered by the light scattering particles PC and propagate in other directions. Therefore, the path of the light that is not emitted toward the outside of the display device 1000 can be changed by the plurality of light scattering particles PC, which can increase the amount of light propagated toward the outside of the display device 1000. Therefore, the efficiency of the display device 1000 can be improved and the power consumption can be reduced.

[0148] Exemplary embodiments of the present disclosure may also be described as follows:

[0149] According to one aspect of the present disclosure, a display device includes: a display panel including a plurality of sub-pixels; a reflective electrode, wherein the emitting electrode is disposed in each of the plurality of sub-pixels; a first light-emitting element, wherein the first light-emitting element is disposed on the reflective electrode; a first connecting electrode, wherein the first connecting electrode is disposed on the first light-emitting element and is configured such that at least a portion of the first connecting electrode covers the first light-emitting element; and a second light-emitting element, wherein the second light-emitting element is disposed on the first connecting electrode and is configured to overlap with the first light-emitting element, the first light-emitting element having a larger size than the second light-emitting element.

[0150] The first light-emitting element may include: a first light-emitting layer; a first n-type electrode disposed on the first light-emitting layer; and a first p-type electrode disposed below the first light-emitting layer. The second light-emitting element may include: a second light-emitting layer; a second n-type electrode disposed below the second light-emitting layer; and a second p-type electrode disposed on the second light-emitting layer, and the first n-type electrode and the second n-type electrode may be electrically connected to the first connection electrode.

[0151] The display device may further include a second connection electrode disposed on the second light emitting element, the first p-type electrode may be electrically connected to the reflective electrode, and the second connection electrode may be electrically connected to the second p-type electrode, the reflective electrode, and the first p-type electrode.

[0152] The first light emitting element and the second light emitting element may be connected in parallel.

[0153] The first connection electrode may be made of an opaque conductive material and configured to reflect light emitted from the first light emitting element and light emitted from the second light emitting element.

[0154] The first connection electrode may be disposed to overlap a portion of the first light emitting element, and the first light emitting element may include a portion overlapping the first connection electrode and a portion not overlapping the first connection electrode.

[0155] The first connection electrode may include a plurality of opening portions at least partially overlapping the first light emitting element.

[0156] The first connection electrode may include: a first electrode layer made of a transparent conductive material; and a second electrode layer disposed on the first electrode layer, the second electrode layer made of an opaque conductive material and configured to reflect light emitted from the first light emitting element and light emitted from the second light emitting element.

[0157] The first connection electrode may include one or more transmission portions formed by patterning the second electrode layer, so that only the first electrode layer can be disposed in the transmission portion and a portion of light emitted from the first light emitting element can pass through the transmission portion and propagate toward an upper side of the first light emitting element.

[0158] The one or more transmissive portions may be arranged to at least partially overlap the first light emitting element.

[0159] One or more of the transmissive portions may have a closed loop shape.

[0160] The display device may further include: a planarization layer disposed between the reflective electrode and the first connection electrode and disposed to surround the first light emitting element; and a plurality of light scattering particles disposed in the planarization layer, and a portion of light emitted from the first light emitting element may be scattered by the plurality of light scattering particles.

[0161] Although the exemplary embodiments of the present disclosure have been described in detail with reference to the accompanying drawings, the present disclosure is not limited thereto and can be implemented in a variety of different forms without departing from the technical concept of the present disclosure. Therefore, the exemplary embodiments of 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 exemplary embodiments described above are illustrative in all aspects and do not limit the present disclosure. All technical concepts within the equivalent scope of the present disclosure should be deemed to fall within the scope of the present disclosure.

Claims

1. A display device, comprising: A display panel, the display panel comprising a plurality of sub-pixels; a reflective electrode, the reflective electrode being disposed in each of the plurality of sub-pixels; a first light emitting element, wherein the first light emitting element is disposed on the reflective electrode; a first connection electrode, the first connection electrode being disposed on the first light emitting element and configured such that at least a portion of the first connection electrode covers the first light emitting element; as well as a second light emitting element, the second light emitting element being disposed on the first connection electrode and being configured to overlap with the first light emitting element, The first light emitting element has a larger size than the second light emitting element.

2. The display device according to claim 1, wherein: The first light emitting element comprises: a first light-emitting layer; a first n-type electrode, the first n-type electrode being disposed on the first light-emitting layer; and a first p-type electrode, the first p-type electrode being disposed below the first light-emitting layer, Wherein, the second light emitting element comprises: a second light-emitting layer; a second n-type electrode, the second n-type electrode being disposed below the second light emitting layer; and a second p-type electrode, the second p-type electrode being disposed on the second light-emitting layer, and The first n-type electrode and the second n-type electrode are electrically connected to the first connection electrode.

3. The display device according to claim 2, further comprising: a second connecting electrode, wherein the second connecting electrode is disposed on the second light emitting element, wherein the first p-type electrode is electrically connected to the reflective electrode, and The second connection electrode is electrically connected to the second p-type electrode, the reflective electrode and the first p-type electrode.

4. The display device according to claim 3, wherein: The first light emitting element and the second light emitting element are connected in parallel.

5. The display device according to claim 2, wherein: The first connection electrode is made of an opaque conductive material and is configured to reflect light emitted from the first light emitting element and light emitted from the second light emitting element.

6. The display device according to claim 5, wherein: The first connection electrode is arranged to overlap a portion of the first light emitting element, and The first light emitting element includes a portion overlapping with the first connecting electrode and a portion not overlapping with the first connecting electrode.

7. The display device according to claim 5, wherein: The first connection electrode includes a plurality of opening portions at least partially overlapping the first light emitting element.

8. The display device according to claim 2, wherein: The first connecting electrode comprises: a first electrode layer made of a transparent conductive material; and A second electrode layer is provided on the first electrode layer, the second electrode layer is made of an opaque conductive material and is configured to reflect light emitted from the first light emitting element and light emitted from the second light emitting element.

9. The display device according to claim 8, wherein: The first connection electrode includes one or more transmission portions formed by patterning the second electrode layer so that only the first electrode layer is disposed in the transmission portions, and Part of the light emitted from the first light emitting element passes through the transmission portion and travels toward an upper side of the first light emitting element.

10. The display device according to claim 9, wherein: The one or more transmissive portions are arranged to at least partially overlap with the first light emitting element.

11. The display device according to claim 9, wherein: The one or more transmission parts have a closed loop shape.

12. The display device according to claim 2, further comprising: a planarization layer, the planarization layer being disposed between the reflective electrode and the first connection electrode and being disposed to surround the first light emitting element; as well as a plurality of light scattering particles disposed in the planarization layer, Part of the light emitted from the first light emitting element is scattered by the plurality of light scattering particles.

13. The display device according to claim 1, wherein: The first light emitting element comprises: The first light-emitting layer, a first n-type semiconductor layer, a first p-type semiconductor layer, and The first protective film, wherein the first protective film is formed to cover at least a portion of the first n-type semiconductor layer, at least a portion of the first light emitting layer, and at least a portion of the first p-type semiconductor layer, and Wherein, the second light emitting element comprises: The second light-emitting layer, The second n-type semiconductor layer, a second p-type semiconductor layer, and The second protective film, The second protection film is formed to cover at least a portion of the second n-type semiconductor layer, at least a portion of the second light emitting layer, and at least a portion of the second p-type semiconductor layer.

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