Light emitting display device

Abstract

The light emitting display device can include a substrate having first to third sub-pixels, transistors respectively at the first to third sub-pixels on the substrate, a planarization layer on the transistors, first to third light emitting devices on the planarization layer, the first to third light emitting devices respectively emitting red, green, and blue light in the first to third sub-pixels. The third light emitting device can include a first blue light emitting stack including a first blue light emitting layer between an anode and a charge generation layer, and a second blue light emitting stack including a second blue light emitting layer between the charge generation layer and a cathode, each of the first and second blue light emitting layers including a plurality of sub-light emitting layers, and a thickness of the second blue light emitting layer being greater than a thickness of the first blue light emitting layer.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2025-0057713, filed in Korea on April 30, 2025, the entire contents of which are expressly incorporated herein by reference as if fully set forth herein. Technical Field

[0003] This disclosure relates to a light-emitting display device including a display device with improved efficiency and lifespan. Background Technology

[0004] With the advent of the information society, displays used to visually represent electronic information signals have developed rapidly. In response, various display devices with excellent performance characteristics such as thinness, light weight, and low power consumption are being developed.

[0005] Among various display devices, light-emitting display devices are becoming increasingly competitive due to their compact size and clear colors, as they can emit their own light without requiring a separate light source.

[0006] The light-emitting device may include an anode and a cathode facing each other as electrodes, and a light-emitting layer is disposed between the anode and the cathode, whereby the common layer can be configured to transport holes and electrons to the light-emitting layer to generate light.

[0007] Light-emitting display devices can include color-emitting layers to represent various colors, but these layers suffer from differences in efficiency and lifespan characteristics. Therefore, there is a need to develop light-emitting devices with color-emitting layers that address these differences in efficiency, lifespan characteristics, and structures.

[0008] Therefore, research has actively focused on improving the durability of color-emitting layers, which may have a relatively short lifespan, in order to maintain uniform color in the display device throughout its lifespan. Summary of the Invention

[0009] Therefore, this disclosure relates to a light-emitting display device that substantially eliminates one or more problems caused by the limitations and disadvantages of related technologies.

[0010] One aspect of this disclosure is to provide a light-emitting device comprising multiple light-emitting layers, which can improve efficiency, reduce operating voltage, and simultaneously extend the lifetime of at least some sub-pixels.

[0011] Another aspect of this disclosure is to provide a light-emitting display device comprising a plurality of light-emitting layers, each light-emitting layer being disposed in a first light-emitting stack and a second light-emitting stack that overlap each other, wherein the thickness relationship between the light-emitting layers is defined such that the recombination region of holes and electrons is spaced apart from the interface between the light-emitting layer and the common layer, thereby preventing a reduction in lifetime due to the accumulation of charge carriers or excitons at the interface of the light-emitting layers.

[0012] Another aspect of this disclosure is to provide a light-emitting display device in which each of the stacked plurality of light-emitting layers includes a plurality of sub-light-emitting layers with different bodies, such that the triplet-triple annihilation TTA efficiency in the second sub-light-emitting layer, which is the thickest layer, can be enhanced, and thus the exciton utilization and luminous efficiency within the light-emitting layer can be improved.

[0013] Another aspect of this disclosure is to provide a light-emitting display device in which, in a multi-emitting layer, a first sub-emitting layer adjacent to a hole transport common layer includes a first body having a small HOMO energy level difference with a dopant, and a second sub-emitting layer includes a second body having a HOMO energy level lower than that of the first body, thereby facilitating hole transfer from the first sub-emitting layer to the second sub-emitting layer and preventing holes from being trapped at the interface between the hole transport common layer and the emitting layers.

[0014] Another aspect of this disclosure is to provide a light-emitting display device that includes multiple light-emitting stacks in each sub-pixel in a top-emitting manner to improve luminous efficiency and to minimize or reduce color shift due to viewing angle changes in a structure having multiple stacked light-emitting layers, thereby providing uniform visual perception regardless of viewing angle changes.

[0015] Another aspect of this disclosure is to provide a light-emitting display device that exhibits improved lifetime due to differences in the concentration of dopants included in different stacked light-emitting layers.

[0016] The aspects to be achieved by this disclosure are not limited to those mentioned above. Other aspects not mentioned herein will be clearly understood by those skilled in the art from the following description.

[0017] Additional advantages, aspects, and features of this disclosure will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon review of the following, or may be learned from practice of this disclosure. Aspects and other advantages of this disclosure may be realized and obtained by means of structures particularly pointed out in the written description, its claims, and the accompanying drawings.

[0018] A light-emitting display device according to an embodiment of the present disclosure includes: a substrate including a first sub-pixel to a third sub-pixel; a transistor in each of the first to third sub-pixels disposed on the substrate; a planarization layer disposed on the transistor; a first light-emitting device, a second light-emitting device, and a third light-emitting device disposed on the planarization layer, the first light-emitting device, the second light-emitting device, and the third light-emitting device emitting red light, green light, and blue light respectively in the first to third sub-pixels; and an encapsulation layer above the first to third light-emitting devices.

[0019] Each of the first to third light-emitting devices may include an anode and a cathode facing each other, and a charge generation layer between the anode and the cathode. The third light-emitting device may include a first blue light-emitting stack and a second blue light-emitting stack, the first blue light-emitting stack having a first blue light-emitting layer between the anode and the charge generation layer, and the second blue light-emitting stack having a second blue light-emitting layer between the charge generation layer and the cathode.

[0020] Each of the first blue emitting layer and the second blue emitting layer may include multiple sub-emitting layers, and the thickness of the second blue emitting layer may be greater than the thickness of the first blue emitting layer.

[0021] It should be understood that both the foregoing general description and the following detailed description of this disclosure are exemplary and illustrative, and are intended to provide further explanation of the claimed disclosure. Attached Figure Description

[0022] The accompanying drawings, included to provide a further understanding of this disclosure and incorporated into and forming part of this application, illustrate embodiments of this disclosure and, together with the specification, serve to illustrate the principles of this disclosure. In the drawings:

[0023] Figure 1 This is a plan view showing a light-emitting display device according to an embodiment of the present disclosure;

[0024] Figure 2 It is along Figure 1 A cross-sectional view taken by line I-I' in the diagram;

[0025] Figure 3 It is shown Figure 2 A cross-sectional view of the light-emitting devices from the first sub-pixel to the third sub-pixel;

[0026] Figure 4 yes Figure 3 The energy band diagram of the first to third sub-emitting layers of the blue emitting layer included in the third sub-pixel;

[0027] Figure 5 yes Figure 3PL spectra of blue dopants in the first and second blue emitting layers, green dopants in the first and second green emitting layers, and red dopants in the first and second red emitting layers;

[0028] Figure 6 The location of the composite region is shown, depending on the thickness of the first sub-emitting layer in the multilayer blue emitting layer structure of Experimental Examples 1 to 3;

[0029] Figure 7 This is an energy band diagram of the first and second blue light-emitting layers of the third sub-pixel in a light-emitting display device according to an embodiment of the present disclosure;

[0030] Figure 8 This is the band structure diagram of the hole transport common layer and the blue emitting layer in the first and second stacks;

[0031] Figure 9 The location of the composite region formed depends on the thickness of the first sub-emitting layer in the first blue emitting stack in Experimental Examples 4 to 6;

[0032] Figure 10 The location of the composite region formed depends on the thickness of the first sub-emitting layer in the second blue emitting stack in Experimental Examples 7 to 9;

[0033] Figure 11 The viewing angle characteristics obtained by changing the thickness of the first sub-emitting layer of the first blue emitting layer are shown when the cathode is formed of AgMg with a thickness of 15 nm and when the cathode is formed of IZO with a thickness of 20 nm.

[0034] Figure 12 The viewing angle characteristics obtained by changing the thickness of the first sub-emitting layer of the second blue emitting layer are shown when the cathode is formed of AgMg with a thickness of 15 nm and when the cathode is formed of IZO with a thickness of 20 nm.

[0035] Figure 13 The viewing angle characteristics obtained by changing the thickness of the first sub-emitting layer of the first blue emitting layer are shown when the cathode is formed of AgMg with a thickness of 15 nm and when the cathode is formed of ITO with a thickness of 20 nm.

[0036] Figure 14 The viewing angle characteristics obtained by changing the thickness of the first sub-emitting layer of the second blue emitting layer are shown when the cathode is formed of AgMg with a thickness of 15 nm and when the cathode is formed of ITO with a thickness of 20 nm; and

[0037] Figure 15 This is a cross-sectional view showing a light-emitting display device according to another embodiment of the present disclosure. Detailed Implementation

[0038] The advantages and features of this disclosure, as well as the methods for achieving these advantages and features, will be described with reference to this document and its appendices. Figure 1 As will become apparent from the exemplary embodiments described in detail below, this disclosure should not be construed as limited to the exemplary embodiments disclosed below, and may be embodied in various different forms. Therefore, these exemplary embodiments are set forth only to make this disclosure sufficiently complete and to assist those skilled in the art in fully understanding its scope. The scope of protection of this disclosure is defined by the claims and their equivalents.

[0039] In the following description of this disclosure, detailed descriptions of relevant known steps, components, functions, techniques, and configurations may be omitted where such descriptions might unnecessarily obscure the focus of this disclosure. Furthermore, the component names used in the following description are chosen for clarity of description and may differ from component names in actual products. In addition, numerous specific details are set forth in the following detailed description of this disclosure to provide a full and thorough understanding of it. However, it should be understood that this disclosure can be practiced without these specific details. In other instances, known methods, processes, components, and circuits have not been described in detail to avoid unnecessarily obscuring aspects of this disclosure.

[0040] The shapes, dimensions, scales, angles, numbers, etc., shown in the accompanying drawings to describe various exemplary embodiments of this disclosure are given by way of example only. This disclosure is not limited to the illustrations in the accompanying drawings.

[0041] In this disclosure, unless terms such as “only” are used, one or more components may be added when terms such as “including,” “having,” or “contains” are used. As used herein, the term “and / or” includes a single related enumeration item as well as any and all combinations of two or more related enumeration items. Furthermore, the term “can” covers all the meanings and scope of the term “may,” and vice versa.

[0042] Expressions such as "at least one of..." can modify the entire list of elements when placed before it, but not any individual element within the list. The term "at least one" should be understood to include any and all combinations of one or more related enumerated items. For example, "at least one of the first, second, and third elements" means combinations of all three enumerated elements, combinations of any two of the three elements, and each individual element—the first, second, and third elements.

[0043] The terminology used herein is for the purpose of describing a particular aspect and is not intended to limit this disclosure. As used herein, the terms “a” and “an” used to describe elements in the singular form are intended to include multiple elements. Unless the context clearly specifies otherwise, elements described in the singular form are intended to include multiple elements, and vice versa.

[0044] When interpreting a component or value, even if no explicit description of the error or tolerance range is provided, the component or value should be interpreted as including such an error or tolerance range.

[0045] In describing the various exemplary embodiments of this disclosure, when using terms such as "on," "above," "below," and "next to" to describe the positional relationship between two elements, at least one intermediate element may exist between the two elements unless "immediately," "directly," or "closely" is used. It should be understood that when an element or layer is referred to as "connected to" or "coupled to" another element or layer, it may be directly connected to or coupled to that other element or layer, or one or more intermediate elements or layers may exist.

[0046] In describing various exemplary embodiments of this disclosure, when using terms such as “after,” “following,” “next,” and “before” to describe the temporal relationship between two events, another event may occur between the two events unless more restrictive terms such as “just,” “immediately,” or “exactly” are used.

[0047] In describing the various exemplary embodiments of this disclosure, terms such as “first” and “second” may be used to describe various components. These terms are intended to distinguish identical or similar components from one another and do not limit the aforementioned components. Therefore, throughout this disclosure, unless otherwise expressly stated, a “first” component may be the same as a “second” component within the technical concept of this disclosure.

[0048] Features of the various embodiments of this disclosure may be partially or wholly coupled or combined with each other, and may interoperate with each other in various ways, and are technically driven as will be fully understood by those skilled in the art. Embodiments of this disclosure may be performed independently of each other, or may be performed together in an interdependent relationship.

[0049] As used herein, the terms “LUMO (lowest unoccupied molecular orbital) level” and “HOMO (highest occupied molecular orbital) level” for a layer refer to the LUMO and HOMO levels of the material occupying the majority of the weight of the layer, such as the host material, unless the context explicitly states that the LUMO and HOMO levels refer to the LUMO and HOMO levels of the doped material in the layer, respectively.

[0050] Here, the HOMO level is obtained by measuring the voltage corresponding to the first peak of electron release from the target material via cyclic voltammetry (CV) and comparing it with a reference material whose HOMO level is known. For example, the HOMO level of a material can be measured based on its known oxidation and reduction potentials.

[0051] As used herein, the term "doped" layer refers to a layer comprising a first material and a second material having different physical properties from the first material (e.g., n-type and p-type materials, or organic and inorganic materials). Besides differences in properties, the first and second materials may also differ in their amounts within the doped layer. For example, the host material may be the dominant component, while the dopant may be a minor component. The first material constitutes the majority of the weight of the doped layer. Based on the total weight of the first material in the doped layer, the second material may be added in an amount less than 30% by weight. A "doped" layer can be used to distinguish between the host material and the dopant material of a layer by considering weight ratios. For example, if all materials constituting a layer are organic, and at least one of the materials constituting the layer is n-type and another is p-type, then the layer is considered a "doped" layer when the n-type material is present in an amount less than 30 wt%, or when the p-type material is present in an amount less than 30 wt%.

[0052] Furthermore, the term "undoped" refers to a layer that has not been "doped." For example, a layer can be "undoped" when it comprises a single material or a mixture of materials containing materials with similar properties. For example, if at least one of the materials constituting a layer is p-type and none of the materials constituting the layer is n-type, then the layer is considered "undoped." For example, if at least one of the materials constituting a layer is an organic material and none of the materials constituting the layer is an inorganic material, then the layer is considered "undoped." The term "composed of" for an element can fully encompass the meaning of being entirely formed of that element or simply containing that element.

[0053] In this disclosure, an electroluminescence (EL) spectrum can be calculated by multiplying (a) a photoluminescence (PL) spectrum and (b) an emission or emission spectrum curve, the photoluminescence (PL) spectrum being adapted to the inherent properties of the light-emitting material contained in the organic light-emitting layer, such as the host material or dopant material, the emission or emission spectrum curve being determined by the structure and optical properties of the organic light-emitting element, including the thickness of the organic layer such as the electron transport layer.

[0054] The exemplary embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. When adding reference numerals to elements in each of the drawings, the same reference numerals may refer to the same elements even though the same elements are shown in other drawings.

[0055] In the following description, an embodiment of a light-emitting display device according to the present disclosure will be described with reference to the accompanying drawings. All components of each light-emitting display device according to all embodiments of the present disclosure are operatively coupled and configured.

[0056] Figure 1 This is a schematic diagram illustrating a light-emitting display device according to an embodiment of the present disclosure. Figure 2 It is along Figure 1 The cross-sectional view taken by line I-I' in the figure. Figure 3 It is shown Figure 2 A cross-sectional view of the light-emitting device from the first sub-pixel to the third sub-pixel. Figure 4 yes Figure 3 The energy band diagram of the first to third sub-emitting layers of the blue emitting layer included in the third sub-pixel. Figure 5 yes Figure 3 PL spectra of the blue dopants in the first and second blue emitting layers, the green dopants in the first and second green emitting layers, and the red dopants in the first and second red emitting layers.

[0057] like Figure 1 As shown, the light-emitting display device 1000 according to an embodiment of the present disclosure includes a display panel 11, an image processor 12, a timing controller 13, a data driver 14, a scan driver 15, and a power supply 16.

[0058] Display panel 11 displays images in response to data signals DATA supplied from data driver 14, scan signals supplied from scan driver 15, and power supplied from power supply 16.

[0059] The display panel 11 may include sub-pixels SP disposed at each intersection of multiple gate lines GL and multiple data lines DL. The structure of the sub-pixels SP may vary depending on the type of the light-emitting display device 1000.

[0060] One or more sub-pixels SP can constitute a unit pixel. For example, a unit pixel may include first to third sub-pixels RSP, GSP, and BSP that emit red, green, and blue light, respectively. Alternatively, a unit pixel may include sub-pixels that emit white light in addition to the first to third sub-pixels. In embodiments according to this disclosure, the color type, arrangement type, arrangement order, etc., of the sub-pixels can be determined based on factors such as light-emitting characteristics, device lifetime, and device specifications, and are not limited thereto. For example, more than four sub-pixels may be used.

[0061] The display panel 11 can be divided into a display area (AA: within the dashed area) in which subpixels SP are provided to display images, and a non-display area NA surrounding the display area AA. A scan driver 15 can be installed in the non-display area NA of the display panel 11. Additionally, the non-display area NA may include pad portions PAD, which include pad electrodes PD.

[0062] Here, the display area AA is also called the "valid area", and the non-display area NA is also called the "invalid area".

[0063] In addition to the externally supplied data signal DATA, the image processor 12 can also output a data enable signal DE. Besides the data enable signal DE, the image processor 12 can also output one or more of a vertical synchronization signal, a horizontal synchronization signal, and a clock signal, but these signals are omitted for ease of description.

[0064] In addition to receiving drive signals, the timing controller 13 can also receive data signals DATA from the image processor 12. The drive signals may include a data enable signal DE. Furthermore, the drive signals may include a vertical synchronization signal, a horizontal synchronization signal, and a clock signal. The timing controller 13 includes a data timing control signal DDC for controlling the operating timing of the data driver 14; and a gate timing control signal GDC for controlling the operating timing of the scan driver 15 based on the drive signals.

[0065] The data driver 14 samples and latches the data signal DATA supplied from the timing controller 13 in response to the data timing control signal DDC supplied from the timing controller 13, converts the obtained data signal DATA into a gamma reference voltage, and outputs the gamma reference voltage.

[0066] Data driver 14 can output data signal DATA via data line DL. Data driver 14 can be provided as an integrated circuit IC. For example, data driver 14 can be electrically connected via a flexible circuit film to pad electrodes PD disposed in the non-display area NA of display panel 11.

[0067] The scan driver 15 outputs a scan signal in response to the gate timing control signal GDC supplied from the timing controller 13. The scan driver 15 can output the scan signal via the gate line GL. The scan driver 15 can be implemented as an integrated circuit IC, or it can be implemented in the display panel 11 as a gate GIP in the panel.

[0068] Power supply 16 can output high-potential voltage and low-potential voltage to drive display panel 11. Power supply 16 can provide high-potential voltage to display panel 11 through first power line EVDD (drive power line or pixel power line) and low-potential voltage to display panel 11 through second power line EVSS (auxiliary power line or common power line).

[0069] The display panel 11 is divided into a display area AA and a non-display area NA, and includes a plurality of sub-pixels SP defined by gate lines GL and data lines DL that intersect each other in the display area AA to form a matrix.

[0070] like Figure 2 As shown, each of the sub-pixels RSP, GSP, and BSP may include an luminous portion REM, GEM, or BEM and a non-luminous portion NEM surrounding the luminous portion.

[0071] like Figure 2 As shown, the light-emitting display device 1000 according to an embodiment of the present disclosure may include: a substrate 100, which includes first sub-pixels to third sub-pixels RSP, GSP and BSP; a transistor TFT disposed on the substrate 100; a first planarization layer 105 and a second planarization layer 106 disposed on the transistor TFT; a light-emitting device ED disposed on the second planarization layer 106; and an encapsulation layer 140 disposed on the light-emitting device ED, wherein the transistor TFT, the first planarization layer 105, the second planarization layer 106, the light-emitting device ED and the encapsulation layer 140 are sequentially disposed in each of the first sub-pixels to third sub-pixels RSP, GSP and BSP.

[0072] The light-emitting display device 1000 may include: a touch sensing unit TC on the encapsulation layer 140 capable of detecting touch; and a color filter array unit CFA disposed on each of the first to third sub-pixels RSP, GSP and BSP to display colors.

[0073] The substrate 100, on which the first to third sub-pixels RSP, GSP, and BSP are disposed, can be formed of a single layer or multiple layers. For example, the first sub-pixel RSP can emit red light, the second sub-pixel GSP can emit green light, and the third sub-pixel BSP can emit blue light. The color of the light emitted by the first to third sub-pixels RSP, GSP, and BSP can be determined by the color-emitting layer included in the light-emitting stack of the light-emitting device ED disposed in each sub-pixel and the color filter included in the color filter array CFA. Figure 1 The subpixels shown include, for example, red, green, and blue subpixels, but in addition to red, green, and blue subpixels, subpixels emitting other colors of light may also be provided on the substrate 100. However, embodiments of this disclosure are not limited to this, and other colors may be used.

[0074] The substrate 100 may include at least one of a metal plate, a glass substrate, and a plastic film having a predetermined supporting force. However, embodiments of the present disclosure are not limited thereto. The substrate 100 may be formed of a flexible material. For example, when the substrate 100 is formed of multiple layers, it may have a laminated structure of a first organic layer, an inorganic insulating layer, and a second organic layer. The outermost first organic layer can prevent the introduction of external impurities and has a protective function. The second organic layer can realize surface planarization of the formation surface of the internal array structure and can prevent charge or impurities from transferring from the outside to the inside. The inorganic insulating layer between the first organic layer and the second organic layer can be used to prevent moisture from penetrating and diffusing between the first organic layer and the second organic layer and to prevent conductive impurities from moving to the second organic layer.

[0075] Multiple buffer layers 101 may be disposed on substrate 100. Multiple buffer layers 101 may serve as buffer layers and / or active buffer layers. Multiple buffer layers 101 may be used to prevent impurities from migrating upwards from the lower portion of the active layer 112 and wiring included in the internal array, and may support and protect the upper structure. Multiple buffer layers 101 may include multiple inorganic insulating layers. For example, the inorganic insulating layers included in multiple buffer layers 101 may include at least one of a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer, or an aluminum oxide layer. However, embodiments of this disclosure are not limited thereto.

[0076] Thin-film transistors (TFTs) and storage capacitors can be disposed on the multi-buffer layer 101 in each sub-pixel RSP, GSP, and BSP.

[0077] A light-shielding layer 111 can be provided on the multi-buffer layer 101 to prevent light from being transmitted from below to the active layer 112 of the thin-film transistor TFT.

[0078] A first insulating layer 102 may be provided between the light-shielding layer 111 and the active layer 112 for insulation. The first insulating layer 102 may be formed of an inorganic insulating material and may be formed of, for example, a silicon oxide (SiOx) layer, a silicon nitride (SiNx) layer, a silicon oxynitride (SiOxNy) layer, or multiple layers thereof. However, the embodiments of this disclosure are not limited thereto.

[0079] The thin-film transistor (TFT) can be disposed on each of the plurality of sub-pixels on the first insulating layer 102. For example, the thin-film transistor TFT may include an active layer 112, a gate electrode 113 overlapping the active layer 112 and with a second insulating layer 103 interposed between them, and a first source / drain electrode 114 and a second source / drain electrode 115 connected to the two surfaces of the active layer 112.

[0080] For example, a storage capacitor may include a first storage electrode and a second storage electrode that overlap each other. At least one of the first storage electrode and the second storage electrode may be formed of the same material as the active layer 112, and the other may include the same material as at least one of the gate electrode 113, the first source / drain electrode 114 and the second source / drain electrode 115, or the light-shielding layer 111. However, embodiments of this disclosure are not limited thereto.

[0081] The second insulating layer 103 between the active layer 112 and the gate electrode 113 can be used as a gate insulating layer.

[0082] The active layer 112 may include, for example, a silicon-based semiconductor or an oxide semiconductor. However, embodiments of this disclosure are not limited thereto.

[0083] Silicon-based semiconductors may include crystalline silicon and / or amorphous silicon. Oxide semiconductors may include at least one of gallium oxide, tin oxide, zinc oxide, indium oxide, iron oxide, or indium gallium zinc oxide. In some cases, the oxide semiconductor layer may be formed from multiple layers with different material or composition ratios. At least one sub-pixel RSP, GSP, BSP may include multiple thin-film transistors, and the thin-film transistors may be disposed on different layers. For example, the sub-pixel RSP, GSP, BSP of substrate 100 may include multiple thin-film transistors with different active layers. For example, a first thin-film transistor may be disposed as a silicon-based active layer closer to substrate 100, and a second thin-film transistor may be disposed as an active layer above the first thin-film transistor, and may be provided with different layer structures. However, embodiments of this disclosure are not limited thereto.

[0084] The active layer 112 may include a channel region overlapping with the gate electrode 113 and source / drain regions respectively connected to the first source / drain electrode 114 and the second source / drain electrode 115.

[0085] The second insulating layer 103 can be selectively disposed corresponding to the channel region of the active layer 112, or it can be disposed on the entire surface of the substrate 100 except for the regions through which the first source / drain electrode 114 and the second source / drain electrode 115 pass. The second insulating layer 103 can be used to insulate the active layer 112 from the gate electrode 113. The second insulating layer 103 can be formed of an inorganic insulating material, and can be formed of, for example, a silicon oxide (SiOx) layer, a silicon nitride (SiNx) layer, a silicon oxynitride (SiOxNy) layer, or multiple layers thereof. However, embodiments of this disclosure are not limited thereto.

[0086] The gate electrode 113 may be formed on the second insulating layer 103. The gate electrode 113 may be configured to face the active layer 112, with the second insulating layer 103 inserted between them.

[0087] A third insulating layer 104 may be formed on the gate electrode 113 to cover and protect the gate electrode 113. Furthermore, the third insulating layer 104 may be used to protect at least one electrode of the thin-film transistor (TFT), such as the gate electrode 113 or the active layer 112. The third insulating layer 104 may be formed of an inorganic insulating material. For example, the third insulating layer 104 may be formed of a silicon oxide (SiOx) layer, a silicon nitride (SiNx) layer, a silicon oxynitride (SiOxNy) layer, or multiple layers thereof. However, embodiments of this disclosure are not limited thereto.

[0088] A first source / drain electrode 114 and a second source / drain electrode 115 can be disposed on the third insulating layer 104. The third insulating layer 104 and the second insulating layer 103 have contact holes that allow the first source / drain electrode 114 and the second source / drain electrode 115 to contact each other at both ends of the active layer 112, thereby removing the corresponding area.

[0089] The gate electrode 113, the first source / drain electrode 114, and the second source / drain electrode 115 may each have a single-layer or multi-layer structure.

[0090] When the gate electrode 113, the first source / drain electrode 114, and the second source / drain electrode 115 have a single-layer structure, they can be formed of one selected from the group consisting of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or alloys thereof. However, embodiments of this disclosure are not limited thereto. Alternatively, when the gate electrode 113, the first source / drain electrode 114, and the second source / drain electrode 115 have a multilayer structure, they can have a bilayer structure of molybdenum / aluminum-neodymium, molybdenum / aluminum, titanium / aluminum, molybdenum / titanium, or copper / molybdenum / titanium. Alternatively, the gate electrode 113, the first source / drain electrode 114, and the second source / drain electrode 115 can have a trilayer structure of molybdenum / aluminum-neodymium / molybdenum, molybdenum / aluminum / molybdenum, titanium / aluminum / titanium, or molybdenum / copper / molybdenum. However, embodiments of this disclosure are not limited thereto.

[0091] However, this disclosure is not limited thereto, and the gate electrode 113, the first source / drain electrode 114, and the second source / drain electrode 115 may also have a multilayer structure formed of any material selected from the group consisting of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or alloys thereof. However, embodiments of this disclosure are not limited thereto.

[0092] A first planarization layer 105 and a second planarization layer 106 can be sequentially formed on the third insulating layer 104. The first planarization layer 105 and the second planarization layer 106 planarize the lower structure and prevent steps at the portion where the light-emitting device (ED) is formed, thereby ensuring the characteristics of the light-emitting area and the surface of the light-emitting device.

[0093] The first planarization layer 105 may be provided with contact holes, and the contact holes may be provided with connection electrodes 116 connected to the second source / drain electrode 115. The connection electrodes 116 may be disposed on the same layer as at least one of the transistors, storage capacitors, and light-emitting devices configured to be connected to some of the sub-pixel RSP, GSP, and BSP and supplying a high potential voltage (EVDD), a second power line configured to supply a low potential voltage (EVSS), a reference voltage line, or a reset voltage line.

[0094] The second planarization layer 106 can be configured to cover the connecting electrode 116 and the first planarization layer 105.

[0095] The first planarization layer 105 and the second planarization layer 106 may each comprise an organic material. The organic material may include at least one material selected from the group consisting of acrylic resins, phenolic resins, polyimide resins, unsaturated polyester resins, polyamide resins, benzocyclobutene, polystyrene resins, and polyphenylene sulfide resins. However, embodiments of this disclosure are not limited thereto, and other materials may be used.

[0096] For example, the connecting electrode 116 can be formed as a multilayer, comprising an alloy selected from the group consisting of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu). However, embodiments of this disclosure are not limited thereto. In some cases, the connecting electrode 116 can be omitted. When the connecting electrode 116 is omitted, one of the first source / drain electrode 114 and the second source / drain electrode 115 can be directly connected to the anode (122, AND) of the light-emitting device ED.

[0097] The light-emitting device (ED) comprises a stack of anode (122, AND), intermediate layers (EL: REL, GEL, BEL), and cathode (126). The intermediate layers (EL: REL, GEL, BEL) may include two or more light-emitting stacks in each sub-pixel RSP, GSP, and BSP. The sub-pixels RSP, GSP, and BSP may include color-emitting layers REML1 / REML2, GEML1 / GEML2, and BEML1 / BEML2, which emit different colors of light and are vertically spaced from each other with a charge-generating layer CGL located therebetween. The pattern configuration of each sub-pixel RSP, GSP, or BSP in the intermediate layer EL is referred to as the "red light-emitting pattern portion RS," "green light-emitting pattern portion GS," and "blue light-emitting pattern portion BS."

[0098] Please refer to later Figure 2 The specific configuration of the light-emitting device (ED) will be described, and the upper configuration of the ED will be described first.

[0099] The edge of the anode 122 of each sub-pixel RSP, GSP, BSP may overlap with the dam 128. The area of ​​the anode 122 exposed from the dam 128 may be a light-emitting portion REM, GEM, or BEM. The dam 128 provides an opening for the light-emitting portion REM, GEM, or BEM of each sub-pixel RSP, GSP, or BSP. The dam 128 may include organic or inorganic insulating material. The dam 128 may include transparent and opaque insulating materials. In another embodiment of this disclosure, the dam 128 may have a configuration of laminated opaque and transparent insulating materials.

[0100] Multiple layers, including intermediate layers (EL: REL, GEL, BEL), or at least the first common layers CML1 and CML2, can be set together across the entire display area AA.

[0101] The cathode 126 can be a common layer that is shared across sub-pixels SP and subjected to the same voltage. For this purpose, the cathode 126 can extend from the display area AA to a portion of the non-display area (NA).

[0102] The cathode 126 can be a transparent electrode. The cathode 126 can include a transparent conductive material (TCO) that transmits light, such as indium tin oxide (ITO) or indium zinc oxide (IZO), or a semi-transmissive conductive material, such as magnesium (Mg), silver (Ag), or an alloy of magnesium (Mg) and silver (Ag). When the cathode 126 comprises a semi-transparent metallic material, the luminous efficiency can be improved through the microcavity. When the cathode 126 comprises a semi-transparent metallic material, its thickness can be thin enough to allow light to pass through.

[0103] The anode 122 includes a reflective electrode to prevent light generated in the intermediate EL layer from being transmitted to the light-shielding component below the anode 122. The light generated in the intermediate EL layer can resonate between the cathode 126 and the anode 122, and is ultimately emitted upwards through the cathode 126. Because the anode 122 includes a reflective component, although it overlaps with wiring and transistor TFTs, the light emitted from the light-emitting device ED can be identified in the REM, GEM, or BEM of the light-emitting portion without interference from the components below the light-emitting device ED, and thus does not affect the setup.

[0104] The light-emitting display device according to embodiments of this disclosure exhibits a top-emitting method with the light emission direction upward. In this case, the anode 122 includes a reflective electrode, and light generated from the intermediate layer EL is reflected and re-reflected between the anode 122 and the cathode 126, resonates, and is ultimately emitted toward the cathode 126. By changing the thickness of the red light-emitting pattern portion RS, the green light-emitting pattern portion GS, and the blue light-emitting pattern portion BS, as well as the first optical compensation layer R'HTL and the second optical compensation layer G'HTL, the sub-pixels RSP, GSP, and BSP can have different microcavity characteristics corresponding to each color.

[0105] like Figure 3 As shown, the cathode 126 also includes a capping layer (CPL) to enhance the light output from the light-emitting device (ED) through refraction and to protect the upper surface of the ED. The capping layer (CPL) may include multiple insulating material layers with different refractive indices. In terms of optical function, the entire structure from the anode (AND) to the capping layer (CPL) can be considered to constitute the light-emitting device (ED). The capping layer (CPL) is disposed between the cathode (CAT) and the encapsulation layer 140.

[0106] An encapsulation layer 140 can also be provided to protect the light-emitting device (ED). The encapsulation layer 140 can have a single-layer or multi-layer structure. When the encapsulation layer 140 consists of multiple layers, it can be formed by laminating at least one inorganic encapsulation layer and at least one organic encapsulation layer. The inorganic encapsulation layer prevents moisture penetration, and the organic encapsulation layer can cover particles and planarize the surface. On the planar surface, the organic encapsulation layer can be disposed inside the inorganic encapsulation layer. In this case, the phenomenon of moisture penetration through the organic encapsulation layer when exposed can be prevented.

[0107] A touch sensing unit TC may be included on the encapsulation layer 140. The touch sensing unit TC may be directly disposed on the encapsulation layer 140. The touch sensing unit TC may include a bridging electrode 151, a first touch insulating layer 152 and a second touch insulating layer 153 disposed on the bridging electrode 151, a first touch electrode 154 and a second touch electrode 155 disposed on the second touch insulating layer 153 in different directions, and a touch protective layer 156 configured to cover the first touch electrode 154 and the second touch electrode 155 and protect the underlying portion. Either the first touch electrode 154 and the second touch electrode 155 may be connected to the bridging electrode 151. The example shown illustrates a configuration in which the second touch electrode 155 passes through the second touch insulating layer 153 and the first touch insulating layer 152 and is connected to the bridging electrode 151. However, this disclosure is not limited thereto, and the first touch electrode 154 may also be connected to the bridging electrode.

[0108] At least one of the bridging electrode 151 or the first touch electrode 154 and the second touch electrode 155 may include a mesh structure.

[0109] Furthermore, the bridging electrode 151, the first touch electrode 154, and the second touch electrode 155 can be configured to overlap with the embankment 128 to prevent external visibility.

[0110] The bridging electrode 151, the first touch electrode 154, and the second touch electrode 155 may each be independently formed from a transparent electrode such as ITO or IZO, or from one selected from the group consisting of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof, or a multi-metal laminate structure. However, embodiments of this disclosure are not limited thereto.

[0111] A color filter array CFA, including a light-shielding layer 161 and color filters (162: 162a, 162b, 162c), can be disposed on a touch protection layer 156 at the top of the touch sensing unit TC. The color filter array CFA may also include a transparent protective layer 170 protecting the light-shielding layer 161 and the color filters 162. The light-shielding layer 161 can block light across the entire visible light wavelength range. The color filters 162 may include a red color filter 162a disposed in a first sub-pixel RSP, a green color filter 162b disposed in a second sub-pixel GSP, and a blue color filter 162c disposed in a third sub-pixel BSP. The red color filter 162a has selective transmittance for red wavelengths and is light-blocking for visible light other than red wavelengths. Similarly, the green color filter 162b is light-blocking for visible light other than green wavelengths. The blue color filter 162c is light-blocking for visible light other than blue wavelengths.

[0112] Therefore, red light generated by the intermediate layer REL emitting red light in the first sub-pixel RSP can pass through the red filter 162a without loss in the red wavelength band and be emitted to the outside. Similarly, green light generated by the intermediate layer GEL emitting green light in the second sub-pixel GSP can pass through the green filter 162b without loss in the green wavelength band and be emitted to the outside. And blue light generated by the intermediate layer BEL emitting blue light in the third sub-pixel BSP can pass through the blue filter 162c without loss in the blue wavelength band and be emitted to the outside.

[0113] From the perspective of external light reflection, the configuration of the color filter array (CFA) acts as an anti-reflection layer by blocking external light. For example, the light-shielding layer 161 provided in the non-emitting part (NEM) can block external light from transmitting downwards. The red color filter 162a, green color filter 162b, and blue color filter 162c, respectively provided corresponding to the emitting parts (REM, GEM, and BEM), can block light outside the wavelengths with selective transmittance, thereby preventing external light reflection from each emitting part (REM, GEM, and BEM).

[0114] The anode (122, AND) is independently disposed in each sub-pixel RSP, GSP, and BSP. The anode (122, AND), also referred to as the "first electrode" or "pixel electrode," is connected to the thin-film transistor and enables selective operation of the light-emitting devices disposed in each sub-pixel. The cathode 126, also referred to as the "second electrode" or "common electrode," is shared by multiple sub-pixels RSP, GSP, and BSP disposed on the substrate 100. The cathode (126, CAT) can be grounded or connected to a low-voltage line.

[0115] The anodes (122, AND) of adjacent sub-pixels RSP, GSP, and BSP are spaced apart to enable independent signal applications. The anodes (122, AND) can be connected to the connection electrode 116 through contact holes provided in the second planarization layer 106, or directly connected to the thin-film transistor TFT through contact holes continuously provided in the first planarization layer 105 and the second planarization layer 106.

[0116] The anode 122 may comprise a metallic material with high reflectivity. For example, the anode 122 may be formed as a multilayer structure, such as a laminate of aluminum (Al) and titanium (Ti) (Ti / Al / Ti), a laminate of aluminum (Al) and indium tin oxide (ITO) (ITO / Al / ITO), an APC (Ag / Pd / Cu) alloy, a laminate of APC alloy and ITO (ITO / APC / ITO), a laminate of silver (Ag) and molybdenum / titanium alloy (Ag / MoTi), or may comprise a single-layer structure formed of one or an alloy of two or more materials selected from silver (Ag), aluminum (Al), molybdenum (Mo), gold (Au), magnesium (Mg), calcium (Ca), and barium (Ba). However, embodiments of this disclosure are not limited thereto. The anode 122 may be referred to as a "reflective electrode".

[0117] An intermediate layer EL is disposed on the anode 122. The intermediate layer EL may include a first hole-related common layer CML1, an organic light-emitting layer (EML), and a second electron-related common layer CML2.

[0118] Reference Figure 2 The first common layer CML1 is a hole-related common layer and may include a hole injection layer HIL, a first hole transport layer HTL1, and an electron blocking layer EBL.

[0119] The second common layer CML2 is an electron-related common layer and may include a second hole-blocking layer HBL2, an electron transport layer ETL, and an electron injection layer EIL.

[0120] A cathode CAT 126 can be disposed on the second common layer CML2. The cathode 126 can be a reflective-transmitting electrode or a transparent electrode. When the cathode 126 is a transparent electrode, it can be a transparent conductive material TCO that transmits light, such as ITO (indium tin oxide) or IZO (indium zinc oxide). When the cathode 126 is a reflective-transmitting electrode, it can include a semi-transmitting conductive material, such as magnesium (Mg), silver (Ag), or an alloy of magnesium (Mg) and silver (Ag). When the cathode 126 includes a semi-transmitting conductive material, the luminous efficiency can be improved through the microcavity. When the cathode 126 includes a semi-transmitting metallic material, its thickness can be thin enough to allow light to pass through.

[0121] The first common layer CML1, the second common layer CML2, and the cathode (126, CAT) are jointly disposed in the first to third sub-pixels RSP, GSP, and BSP. Furthermore, they are disposed not only in the light-emitting portions REM, GEM, and BEM of the first to third sub-pixels RSP, GSP, and BSP, but also in the non-light-emitting portion NEM. Figure 2 As shown.

[0122] The first common layer CML1 and the second common layer CML2 are jointly disposed on the substrate 100 in the display area AA, which includes multiple sub-pixels, and can be disposed continuously without interruption.

[0123] In the light-emitting display device according to embodiments of the present disclosure, each light-emitting device ED disposed in the first to third sub-pixels RSP, GSP, and BSP comprises two or more stacks, each stack being distinguished by a charge generation layer. In the first to third sub-pixels RSP, GSP, and BSP, the light-emitting device includes light-emitting pattern portions RS, GS, and BS, which are respectively patterned and disposed between at least a first common layer CML1 and a second common layer CML2. The light-emitting pattern portions RS, GS, and BS include color-emitting layers corresponding to the first to third sub-pixels RSP, GSP, and BSP, respectively.

[0124] Figure 3 An example is shown where the intermediate layers REL, GEL, and BEL of the light-emitting devices for the first to third sub-pixels RSP, GSP, and BSP each consist of two stacks.

[0125] The first sub-pixel RSP includes a first common layer CML1, a red emitting pattern portion RS, and a second common layer CML2. The red emitting pattern portion RS includes a first red emitting layer REML1 and a second red emitting layer REML2, which are contained in different emitting stacks S1 and S2, with a charge generation layer CGL inserted between them. The red emitting pattern portion RS may also include a first hole blocking layer HBL1, a charge generation layer CGL, a second hole transport layer HTL2, and a first optical compensation layer R'HTL between the first red emitting layer REML1 and the second red emitting layer REML2.

[0126] The first red emitting layer REML1 and the second red emitting layer REML2, as well as the first optical compensation layer R'HTL in the first sub-pixel RSP, are spaced apart from the second sub-pixel GSP and the third sub-pixel BSP, and thus have a patterned configuration. On the other hand, the first hole blocking layer HBL1, the charge generation layer CGL, and the second hole transport layer HTL2 of the red emitting pattern RS can be formed as a third common layer CML3 extending horizontally continuously in the sub-pixels RSP, GSP, and BSP. The charge generation layer CGL may include, for example, an n-type charge generation layer NCGL that generates electrons and supplies electrons to the first emitting stack S1, and a p-type charge generation layer PCGL that generates holes and supplies holes to the second emitting stack S2. However, embodiments of this disclosure are not limited thereto.

[0127] The second sub-pixel GSP includes a first common layer CML1, a green emitting pattern portion GS, and a second common layer CML2. The green emitting pattern portion GS includes a first green emitting layer GEML1 and a second green emitting layer GEML2, which are contained in different emitting stacks S1 and S2, with a charge generation layer CGL located between them. The green emitting pattern portion GS may also include a third common layer CML3 and a second optical compensation layer G'HTL between the first green emitting layer GEML1 and the second green emitting layer GEML2. A first hole blocking layer HBL1, a charge generation layer CGL, and a second hole transport layer HTL2 are stacked in the third common layer CML3.

[0128] The third sub-pixel BSP includes a first common layer CML1, a blue emitting pattern portion BS, and a second common layer CML2. The blue emitting pattern portion BS includes a first blue emitting layer BEML1 and a second blue emitting layer BEML2, which are contained in different emitting stacks S1 and S2, with a charge generation layer CGL located between them. The blue emitting pattern portion BS may also include a third common layer CML3 between the first blue emitting layer BEML1 and the second blue emitting layer BEML2, in which a first hole blocking layer HBL1, a charge generation layer CGL, and a second hole transport layer HTL2 are stacked.

[0129] In a light-emitting display device according to one embodiment of the present disclosure, a first blue light-emitting layer BEML1 may include first to third sub-light-emitting layers BEML1a, BEML1b, and BEML1c, each with a different body, and a second blue light-emitting layer BEML2 may include first to third sub-light-emitting layers BEML2a, BEML2b, and BEML2c, each with a different body. The first sub-light-emitting layers BEML1a and BEML2a, the second sub-light-emitting layers BEML1b and BEML2b, and the third sub-light-emitting layers BEML1c and BEML2c are arranged in this order. The second sub-light-emitting layers BEML1b and BEML2b are intermediate layers in each blue light-emitting layer BEML1 and BEML2, the first sub-light-emitting layers BEML1a and BEML2a are relatively close to the anode (AND, 122), and the third sub-light-emitting layers BEML1c and BEML2c are relatively close to the cathode (CAT, 126).

[0130] like Figure 3 As shown, in at least one of the blue emitting layers BEML, namely the first blue emitting layer BEML1 and the second blue emitting layer BEML2, the first sub-emitting layer BEMLa and the third sub-emitting layer BEMLc may include the same first host BH1 and the same blue dopant BD. The second sub-emitting layer BEMLb, disposed between the first sub-emitting layer BEMLa and the third sub-emitting layer BEMLc, includes a second host BH2 and the blue dopant BD, wherein the second host BH2 has a triplet energy level T1_BH2 lower than the triplet energy level T1_BH1 of the first host BH1. When the blue emitting layer BEML comprises consecutive first to third sub-emitting layers BEMLa, BEMLb, and BEMLc, the blue dopant BD may include the same material.

[0131] There are fundamental differences between adjacent sub-emitting layers (BEMLa, BEMLb, and BEMLc). Dexter energy transfer can occur from the first sub-emitting layer BEMLa and the second sub-emitting layer BEMLb, which includes a first host BH1 with a high triplet energy level, to the second sub-emitting layer BEMLb with a low triplet energy level, through the interface between the first sub-emitting layer BEMLa and the second sub-emitting layer BEMLb, which includes a first host BH1 with a high triplet energy level.

[0132] The first component BH1 may be, for example, a compound comprising a pyrene derivative. The second component BH2 may be, for example, a compound comprising anthracene derivatives. However, embodiments of this disclosure are not limited thereto.

[0133] Blue dopant BD is a fluorescent dopant with an emission peak at wavelengths from 420 nm to 495 nm. Blue dopant BD can be, for example, a boron-based fluorescent dopant containing boron in its core. However, embodiments of this disclosure are not limited thereto. The triplet level T1_BD of the blue dopant BD can be higher than the triplet level T1_BH1 of the first host BH1 and the triplet level T1_BH2 of the second host BH2, respectively. For example, the triplet level T1_BD1 of the first blue dopant BD1 can be higher than the triplet level T1_BH1 of the first host BH1 and the triplet level T1_BH2 of the second host BH2, respectively.

[0134] The blue dopant BD, co-located in the first to third sub-emitting layers BEMLa, BEMLb, and BEMLC, possesses hole-trapping properties. Holes are transferred to the blue emitting layer BEML via the electron blocking layer EBL or the second hole transport layer HTL2, while electrons are transferred via the first hole blocking layer HBL1 or the second hole blocking layer HBL2. The recombination region mainly forms in the first sub-emitting layer BEMLa, adjacent to the location of the second hole transport layer HTL2 or the electron blocking layer EBL that directly transfers holes to the blue emitting layer BEML. In the recombination region, the combination of holes and electrons generates singlet excitons, which then fall into the ground state, causing instantaneous emission. Therefore, the first sub-emitting layer BEMLa has high instantaneous luminous efficiency. However, in the light-emitting display device of the present disclosure, the second sub-emitting layer BEMLb contains a second host BH2 with a relatively low triplet energy level, and receives energy through the first sub-emitting layer BEMLa and the third sub-emitting layer BEMLc, thereby generating abundant triplet excitons and fluorescence in the blue dopant BD delayed by triplet-triplet annihilation TTA or triplet-triplet fusion TTF in the second sub-emitting layer BEMLb, increasing the utilization rate of excitons in the blue emitting layer and improving the luminous efficiency.

[0135] Besides the main body, the first to third sub-emitting layers of the blue BEML layer, namely BEMLa, BEMLb, and BEMLc, also have thickness differences. The second sub-emitting layer BEMLb in the middle layer has the thickest second thickness (D2), while the third sub-emitting layer BEMLc has the thinnest third thickness (D3). The first sub-emitting layer BEMLa has a first thickness (D1) greater than the third thickness (D3) but less than the second thickness (D3). <D1<D2)。

[0136] Although the first sub-emissive layer BEMLa generates light immediately via singlet excitons, excess excitons cannot be used for recombination and accumulate at the interface with the adjacent electron blocking layer EBL or the second hole transport layer HTL2, which may lead to a shortened lifetime of the light-emitting device. Accordingly, the light-emitting display apparatus according to the embodiments of the present disclosure prevents the reduction in the lifetime of the light-emitting device caused by excitons diffusing to the interface with the electron blocking layer EBL or the second hole transport layer HTL2 by: ensuring the thickness D2 of the second sub-emissive layer BEMLb that induces delayed fluorescence via TTA or TTF in addition to the first sub-emissive layer BEMLa that generates light immediately, and making the first sub-emissive layer BEMLa thinner than the second sub-emissive layer BEMLb (D1<D2). In addition, the second sub-emissive layer BEMLb having the thickness can ensure a balance between prompt fluorescence and delayed fluorescence in the blue emissive layer BEML, and minimize or reduce carriers that are not used for recombination in the blue emissive layer BEML.

[0137] The third sub-emissive layer BEMLc is configured to transfer energy to the second sub-emissive layer BEMLb and control the speed at which electrons are transferred from the first hole blocking layer HBL1 or the second hole blocking layer HBL2 to the blue emissive layer BEML, such that the recombination region can be partially separated from the electron blocking layer EBL or the second hole transport layer HTL2.

[0138] Among the first blue emissive layer BEML1 and the second blue emissive layer BEML2, the thickness of the second blue emissive layer BEML2 is preferably greater than the thickness of the first blue emissive layer BEML1. Here, the comparison of the thickness between the first blue emissive layer BEML1 and the second blue emissive layer BEML2 may be based on the total thickness of the first to third sub-emissive layers.

[0139] The first green emissive layer GEML1 and the second green emissive layer GEML2 may each include a green dopant GD and a green host. The green dopant may be a phosphorescent dopant and / or a fluorescent dopant. The green host may include both a hole-transporting host and an electron-transporting host.

[0140] The first red emissive layer REML1 and the second red emissive layer REML2 may each include a red dopant GD and a red host. The red dopant RD may be a phosphorescent dopant and / or a fluorescent dopant. The red host may include both a hole-transporting host and an electron-transporting host.

[0141] In a light-emitting display device, a viewer can view the device not only in the normal direction of the substrate 100 but also at various viewing angles relative to the substrate 100. When a viewer views the light-emitting display device in the normal direction of the substrate 100, the viewing angle is defined as 0°. The angle formed between the viewer's viewing direction and the normal direction of the substrate 100 when the viewer views the light-emitting display device is defined as the viewing angle. For example, when the change in color coordinates remains within a predetermined range at a viewing angle of 45° or within 60°, the light-emitting display device can be considered to have excellent viewing angle characteristics. However, embodiments of this disclosure are not limited to this.

[0142] Meanwhile, the light-emitting display device according to embodiments of the present disclosure includes a light-emitting device comprising a first color light-emitting layer REML1, GEML1, and BEML1 of a first light-emitting stack and a second color light-emitting layer REML2, GEML2, and BEML2 of a second light-emitting stack, wherein the first light-emitting stack and the second light-emitting stack have at least different vertical phases. When the viewing angle changes, the first color light-emitting layer REML1, GEML1, and BEML1, which are relatively farther from the viewer's eye, can cause a greater change in optical distance compared to the second color light-emitting layer REML2, GEML2, and BEML2, which are relatively closer to the viewer's eye. Therefore, considering the change in optical distance depending on the viewing angle, the first color light-emitting layer REML1, GEML1, and BEML1, which are relatively farther from the viewer's eye, can be thinner than the second color light-emitting layer REML2, GEML2, and BEML2 located thereon, thereby reducing the sensitivity to the change in optical distance caused by the first color light-emitting layer REML1, GEML1, and BEML1.

[0143] Additionally, refer to Figure 3 The thicknesses of the first red emitting layer REML1 and the second red emitting layer REML2 may differ from the thicknesses of the first green emitting layer GEML1 and the second green emitting layer GEML2, and also differ from the thicknesses of the first blue emitting layer BEML1 and the second blue emitting layer BEML2. For example, the thicknesses of the first red emitting layer REML1 and the second red emitting layer REML2 may be greater than the thicknesses of the first green emitting layer GEML1 and the second green emitting layer GEML2. Furthermore, the thicknesses of the first green emitting layer GEML1 and the second green emitting layer GEML2 may be greater than the thicknesses of the first blue emitting layer BEML1 and the second blue emitting layer BEML2. However, the embodiments of this disclosure are not limited thereto.

[0144] At the same time, such as Figure 4As shown, compared with the red dopant RD included in the first red emitting layer REML1 and the second red emitting layer REML2 and the green dopant GD included in the first green emitting layer GEML1 and the second green emitting layer GEML2, the blue dopant BD included in the first blue emitting layer BEML1 and the second blue emitting layer BEML2 has a narrow PL (photoluminescence) spectrum.

[0145] Due to the different thicknesses of the luminescent dopants RD, GD, and BD, and the intermediate layers REL, GEL, and BEL, each sub-pixel RSP, GSP, and BSP exhibits a different EL (electroluminescence) spectrum, defined as the product of the PL spectrum and the outgoing coupled emission spectrum. Specifically, when the viewing angle changes, the outgoing coupled emission spectrum shifts towards shorter wavelengths, and compared to the red dopant RD and green dopant GD, the blue dopant BD exhibits a larger EL spectral change due to a smaller shift, potentially resulting in a larger visual perception change in the third sub-pixel BSP when the viewing angle changes. According to embodiments of this disclosure, the light-emitting display device includes a second blue luminescent layer BEML2, which is relatively thicker than the first blue luminescent layer BEML1, in the third sub-pixel BSP, which emits blue light and is highly sensitive to viewing angle changes. This ensures blue light luminous efficiency and maintains lifetime characteristics while reducing sensitivity to viewing angle changes and ensuring viewing angle characteristics.

[0146] The first thickness D1 of the first sub-emitting layer BEMLa, which is made of the same material as at least one of the first blue emitting layer BEML1 and the second blue emitting layer BEML2, may be no less than twice the third thickness D3 of the third sub-emitting layer BEMLc and no more than three times the third thickness D3. The thickness of the first sub-emissive layer BEMLa, which directly emits singlet excitons via instantaneous emission, is greater than the thickness of the third sub-emissive layer BEMLc, which has energy transfer capabilities.

[0147] The blue dopant BD can include, for example, boron-based dopant represented by structural formulas 1 to 9 below. However, this is merely an example and the dopant in embodiments of this disclosure is not limited to the materials described below. Any fluorescent dopant capable of emitting fluorescence and delayed fluorescence, having an emission peak at visible wavelengths of 420 nm to 495 nm, and having a triplet energy level higher than that of the first blue host BH1 and the second blue host BH2 can be used instead.

[0148] [Structure 1]

[0149]

[0150] [Structure 2]

[0151]

[0152] [Structure 3]

[0153]

[0154] [Structure 4]

[0155]

[0156] [Structure 5]

[0157]

[0158] [Structure 6]

[0159]

[0160] [Structure 7]

[0161]

[0162] [Structure 8]

[0163]

[0164] [Structure 9]

[0165]

[0166] Furthermore, in the light-emitting device according to the embodiments of the present disclosure, the triplet energy level of the dopant can be tuned by changing the substituents in at least a portion of any of the compounds in structural formulas 1 to 9.

[0167] Meanwhile, at the first to third sub-pixels RSP, GSP, and BSP, the difference between the first stack S1 and the second stack S2 lies in the following: the electron blocking layer EBL is further disposed below the first red emitting layer REML1, the first green emitting layer GEML1, and the first blue emitting layer BEML1, and above the first hole transport layer HTL1. The second hole transport layer HTL2 is disposed directly below the second red emitting layer REML2, the second green emitting layer GEML2, and the second blue emitting layer BEML2 without an electron blocking layer. This means that the first stack S1 is closer to the anode (AND, 122) and therefore has a faster hole injection rate than the second stack S2, and therefore the electron blocking layer EBL, which is relatively slower than the first hole transport layer HTL1 and the second hole transport layer HTL2, is further disposed on the first stack S1. The electron blocking layer EBL has a higher LUMO energy level than the hole transport material of the adjacent first hole transport layer HTL1 to confine electrons to each of the first color emitting layers REML1, GEML1, and BEML1, and the electron blocking layer EBL may comprise a hole transport material with a lower hole mobility compared to the first hole transport layer HTL1. Preferably, the hole mobility of the first hole transport layer HTL1 may be 1 to 3 orders of magnitude (10 to 1000 times) greater than the hole mobility of the electron blocking layer EBL.

[0168] Reference Figure 4 The band gaps of the first host BH1 and the second host BH2 are described below.

[0169] The HOMO level HOMO1_BH1 of the first subject BH1 is higher than the HOMO level HOMO_BH2 of the second subject BH2, and the LUMO level LUMO1_BH1 of the first subject BH1 can be higher than the LUMO level (LUMO_BH2) of the second subject BH2.

[0170] The HOMO level HOMO_BD of the blue dopant BD is higher than the HOMO level HOMO_BH1 of the first host BH1 and the HOMO level HOMO_BH2 of the second host BH2 (HOMO_BD > HOMO_BH1, HOMO_BD_ > HOMO_BH2). Therefore, since the blue dopant BD has a HOMO level similar to that of the adjacent electron blocking layer EBL or the second hole transport layer HTL2, recombination occurs in the blue dopant BD, which has a shallow HOMO level, when holes are transferred from the electron blocking layer EBL or the second hole transport layer HTL2 to the blue emitting layer BEML. In the light-emitting display device of the present disclosure, the second sub-light-emitting layer BEMLb, which receives energy and charge carriers from the first sub-light-emitting layer BEMLa, is thicker than the first sub-light-emitting layer BEMLa. This allows a composite region RZ that emits light instantly to be formed at a predetermined distance from the interface between the first sub-light-emitting layer BEMLa and the electron blocking layer EBL in the first sub-light-emitting layer BEMLa. This prevents the accumulation of charge carriers and excitons at the interface between the first sub-light-emitting layer BEMLa and the electron blocking layer EBL and improves lifetime characteristics.

[0171] Experimental Examples 1 to 3 (EX1, EX2 and EX3)

[0172] The following will describe the factors that depend on the thickness of the first sub-emitting layer BEMLa. Figure 3 The characteristics of the blue emitting layer BEML of the three sub-emitting layers.

[0173] Figure 6 This is a diagram showing the location of the composite region in experimental examples 1 to 3, depending on the thickness of the first sub-emissive layer in the multilayer blue emitting layer structure.

[0174] [Table 1]

[0175]

[0176] Experimental Examples 1 to 3 EX1, EX2, and EX3 were constructed by sequentially stacking a hole injection layer HIL, a hole transport layer HTL, an electron blocking layer EBL, a blue emitting layer BEML, a hole blocking layer HBL, an electron transport layer ETL, and an electron injection layer between the anode and cathode. The blue emitting layer BEML was configured to include first to third sub-emitting layers BEMLa, BEMLb, and BEMLc, each containing different components, as shown below. Figure 3 As shown. The anode comprises a reflective electrode formed of a silver alloy, and the cathode comprises an AgMg alloy.

[0177] In Experimental Example 1 EX1, the thickness of the first sub-emitting layer BEMLa is 5 nm, the thickness of the second sub-emitting layer BEMLb is 8 nm, and the thickness of the third sub-emitting layer BEMLc is 3 nm. Experimental Example 2 EX2 has the same configuration as Experimental Example 1 EX1 except that the thickness of the first sub-emitting layer BEMLa is 7 nm, and Experimental Example 3 EX3 has the same configuration as Experimental Example 1 EX1 except that the thickness of the first sub-emitting layer BEMLa is 9 nm.

[0178] The voltage, efficiency, and lifetime characteristics are evaluated based on Experiment Example 1 EX1.

[0179] As the thickness of the first sub-emissive layer BEMLa decreases (see...), Figure 2 (BEL) Figure 6 In Experimental Examples 1 to 3 EX1, EX2, and EX3, the recombination regions RZ1, RZ2, and RZ3 may form at the interface between the first sub-emitting layer BEMLa and the electron blocking layer. Furthermore, in Experimental Example 2 EX2, it can be seen that the presence of the recombination region RZ2 in the first sub-emitting layer BEMLa prevents exciton accumulation at any interface, thereby improving lifetime characteristics, as shown in Table 1. Additionally, although the thickness of the first sub-emitting layer BEMLa in Experimental Example 2 EX2 varies significantly compared to Experimental Example 1 EX1, the entire region of the first sub-emitting layer BEMLa is immediately used for emission without carrier accumulation, making carrier and energy transfer from the first sub-emitting layer BEMLa to the second sub-emitting layer BEMLb easy. There is almost no difference in efficiency Er compared to Experimental Example 1 EX1, and the increase in driving voltage is minimal or reduced. Therefore, compared to Experimental Example 1 EX1, the lifetime of Experimental Example 2 EX2 increases by 120%, and thus the driving voltage and efficiency characteristics are almost at the same level. In Experimental Example 2 EX2, the peak of the hole-electron recombination region RZ2 appears in the middle region far from the interface between the first sub-electroluminescent layer BEMLa and the second sub-electroluminescent layer BEMLb, and the tail of the recombination region RZ2 remains within the first sub-electroluminescent layer BEMLa. Therefore, the hole-electron recombination region RZ2 can be entirely located within the first sub-electroluminescent layer BEMLa.

[0180] In Experimental Example 1 EX1, the peak of the hole-electron recombination region RZ1 appears near the interface between the first sub-electron emitting layer BEMLa and the second sub-electron emitting layer BEMLb, causing excess excitons to form at a portion of the interface between the first and second sub-electron emitting layers BEMLa and BEMLb, resulting in a relatively shorter lifetime compared to Experimental Example 2 EX2. Therefore, in Experimental Example 1 EX1, the peak of the hole-electron recombination region RZ1 appears in the middle region near the interface between the first and second sub-electron emitting layers BEMLa and BEMLb, and at least one tail of the recombination region RZ1 can be generated in the second sub-electron emitting layer BEMLb but not in the first sub-electron emitting layer BEMLa.

[0181] In Experimental Example 3 EX3, the recombination region RZ3 is completely separated from the second sub-emitting layer BEMLb, causing the recombination region RZ3 to be locally located on the electron blocking layer EBL. This results in severe lifetime degradation, less exciton diffusion throughout the blue emitting layer BEML, and low efficiency. Therefore, in Experimental Example 3 EX3, the peak of the hole-electron recombination region RZ3 appears in the middle region far from the interface between the first sub-emitting layer BEMLa and the second sub-emitting layer BEMLb, and at least one tail of the recombination region RZ2 is located at or adjacent to the edge of the first sub-emitting layer BEMLa.

[0182] Furthermore, the following text will describe Figure 2 The example structure shows that the first blue emitting layer BEML1 and the second blue emitting layer BEML2 are disposed in different stacks of the third sub-pixel BSP. Because the first blue emitting layer BEML1 and the second blue emitting layer BEML2 are disposed in different stacks, they have different driving voltages, efficiencies, and lifetimes in the multilayer structure.

[0183] Figure 7 This is an energy band diagram of the first and second blue light-emitting layers of a third sub-pixel in a light-emitting display device according to an embodiment of the present disclosure. Figure 8 This is a band structure diagram of the hole transport common layer and the blue emitting layer in the first and second stacks.

[0184] like Figure 7 and Figure 8 As shown, each of the first blue emitting layer BEML1 and the second blue emitting layer BEML2 includes a first sub-emitting layer to a third sub-emitting layer BEML1a / BEML1b / BEML1c, BEML2a / BEML2b and BEML2c.

[0185] The first sub-emitting layer BEML1a and the third sub-emitting layer BEML1c of the first blue emitting layer BEML1 include a first blue host BH1 and a first blue dopant BD1, and the second sub-emitting layer BEML1b of the first blue emitting layer BEML1 includes a second blue host BH2 and the first blue dopant BD1, wherein the second blue host BH2 has a triplet energy level lower than that of the first blue host BH1. ).

[0186] The first sub-emitting layer BEML2a and the third sub-emitting layer BEML2c of the second blue emitting layer BEML2 may include a third blue host BH3 and a second blue dopant BD2, and the second sub-emitting layer BEML2b of the second blue emitting layer BEML2 may include a fourth blue host BH4 and a second blue dopant BD2, wherein the fourth blue host BH4 has a lower triplet energy level than the third blue host BH3. The third blue host BH3 may be the same as the first blue host BH1, and the fourth blue host BH4 may be the same as the second blue host BH2. However, this is an example, and the second blue emitting layer BEML2 of the second stack S2 may be a different material from the first blue emitting layer BEML1 of the first stack S1, as long as the third blue host BH3 has a higher triplet energy level than the fourth blue host BH4.

[0187] The first blue dopant BD1, which is commonly included in the first blue emitting layer BEML1, and the second blue dopant BD2, which is commonly included in the second blue emitting layer BEML2, can be the same or different. The triplet energy levels between the third host BH3 and the fourth host BH4 included in the second blue emitting layer BEML2 and the second blue dopant BD2 are in a certain relationship. In this case, they can be replaced by different materials. The triplet energy level T1_BD2 of the second blue dopant BD2 can be higher than the triplet energy level T1_BH3 of the third host BH3 and the triplet energy level T1_BH4 of the fourth host BH4, respectively.

[0188] Here, because the first blue emitting layer BEML1 of the first stack S1 is more sensitive to changes in viewing angle compared to the second blue emitting layer BEML2, the thickness D1T of the first blue emitting layer BEML1 is less than the thickness D2T of the second blue emitting layer BEML2. For example, the thickness D2T of the second blue emitting layer BEML2 can be greater than the thickness D1T of the first blue emitting layer BEML1. However, the embodiments disclosed herein are not limited thereto.

[0189] The thickness difference between the first blue emitting layer BEML1 and the second blue emitting layer BEML2 exists in each first sub-emitting layer BEML1a and BEML2a, and can be adjusted for each composite region. For example, the thickness D11 of the first sub-emitting layer BEML1a of the first blue emitting layer BEML1 can be less than the thickness D21 of the first sub-emitting layer BEML2a of the second blue emitting layer BEML2, and the thickness D21 of the first sub-emitting layer BEML2a of the second blue emitting layer BEML2 can be less than or equal to 1.5 times the thickness D11 of the first sub-emitting layer BEML1a. However, the embodiments disclosed herein are not limited thereto.

[0190] The HOMO level HOMO_BD1 of the first blue dopant BD1 is higher than the HOMO levels HOMO_BH1 and HOMO_BH2 of each of the first blue host BH1 and the second blue host BH2. Furthermore, the HOMO level HOMO_BD2 of the second blue dopant BD2 can be higher than the HOMO levels HOMO_BH3 and HOMO_BH4 of each of the third and fourth blue dopants. ).

[0191] Among the first sub-emitting layers BEML1a, BEML1b, and BEML1c of the first blue emitting layer BEML1, the second sub-emitting layer BEML1b can be the thickest and the third sub-emitting layer BEML1c can be the thinnest. ).

[0192] Among the first to third sub-emitting layers BEML2a, BEML2b, and BEML2c of the second blue emitting layer BEML2, the second sub-emitting layer BEML2b can be the thickest and the third sub-emitting layer BEML2c can be the thinnest. ).

[0193] The thickness D21 of the first sub-emissive layer BEML2a in the second blue emissive layer BEML2 can be two to three times the thickness D23 of the third sub-emissive layer BEML2c. ).

[0194] In the first blue emitting layer BEML1, the thickness D11 of the first sub-emitting layer BEML1a can be greater than the thickness D13 of the third sub-emitting layer BEML1c, but can not be greater than twice the thickness D13 of the third sub-emitting layer BEML1c (D13≤D11≤D13*2).

[0195] like Figure 8As shown, in the first stack S1, an electron blocking layer EBL with a lower hole mobility than the first hole transport layer HTL1 is disposed in contact with the first blue emitting layer BEML1. This ensures that although the thickness D11 of the first sub-emitting layer BEML1a of the first blue emitting layer BEML1 is less than the thickness D21 of the second sub-emitting layer BEML1b of the second blue emitting layer BEML2, the recombination of holes and electrons does not occur locally at the interface between the first sub-emitting layer BEML1a and the electron blocking layer EBL in the first blue emitting layer BEML1, and thus the reduction in lifetime can be prevented.

[0196] Experimental Examples 4 to 9 (EX4, EX5, EX6, EX7, EX8, EX9)

[0197] In application Figure 3 , Figure 7 and Figure 8 In the structure of the light-emitting display device with a first blue emitting layer BEML1 and a second blue emitting layer BEML2, the device performance, depending on the thickness variation of the first sub-emitting layer to the third sub-emitting layer of the first blue emitting layer BEML1 and the second blue emitting layer BEML2, was experimentally determined. The thickness of each layer described below is an example applied to the experimental examples, and the layer thickness of the light-emitting device in the embodiments of this disclosure is not limited thereto and can be changed as needed, as long as the thickness relationship with adjacent layers is not limited.

[0198] In the following experiment, only the thicknesses of the first sub-emitting layers BEML1a and BEML2a in the first sub-emitting layers of the first blue emitting layer BEML1 and the second blue emitting layer BEML2 were changed, while the rest of the configuration remained the same.

[0199] The structure of the light-emitting device used in Experiment Examples 4 EX4 to 9 EX9 is similar to Figure 2 The same applies as shown, and the light-emitting devices of the first to third sub-pixels RSP, GSP, BSP are configured in the following process.

[0200] Each of the first to third sub-pixels RSP, GSP and BSP on the substrate is provided with an anode AND including a reflective electrode.

[0201] A hole injection layer HIL, a first hole transport layer HTL, and an electron blocking layer EBL are sequentially disposed on the anode AND of the first to third sub-pixels RSP, GSP, and BSP. The hole injection layer HIL comprises a p-type dopant and a hole transport material, and the first hole transport layer HTL comprises the same hole transport material as the hole injection layer HIL. The total thickness of the hole injection layer HIL and the first hole transport layer HTL1 is 40.5 nm, and the electron blocking layer EBL has a thickness of 3 nm. The electron blocking layer EBL comprises a hole transport material with a hole mobility that is 1 to 3 orders of magnitude lower than that of the hole transport material included in the first hole transport layer HTL1.

[0202] A first red emitting layer REML1, comprising a red dopant RD, a hole transport host, and an electron transport host, is formed on the electron blocking layer EBL of the first sub-pixel RSP with a thickness of up to 36 nm.

[0203] A first green emitting layer GEML1, comprising a green dopant GD, a hole transport host, and an electron transport host, is formed on the electron blocking layer EBL of the second sub-pixel GSP with a thickness of up to 30 nm.

[0204] A first blue emitting layer BEML1 is formed, comprising a first sub-emitting layer to a third sub-emitting layer BEML1a, BEML1b, and BEML1c sequentially stacked on the electron blocking layer EBL of the third sub-pixel BSP. In Experimental Example 4 EX4, the first sub-emitting layer BEML1a is formed to a thickness of 5 nm, comprising a first blue host BH1 and a blue dopant BD. Experimental Examples 5 EX5 and 6 EX6 differ in that the thicknesses of the first sub-emitting layer BEML1a are 7 nm and 9 nm, respectively.

[0205] The second sub-emitting layer BEML1b of the first blue emitting layer BEML1 is formed to a thickness of 8 nm, comprising the second blue host BH2 and the blue dopant BD. The third sub-emitting layer BEML1c is formed to a thickness of 3 nm, comprising the first blue host BH1 and the blue dopant BD.

[0206] In the first to third sub-pixels RSP, GSP and BSP, a first hole blocking layer HBL1 with a thickness of 8 nm is provided on each of the first color emitting layers REML1, GEML1 and BEML1, and an n-type charge generating layer NCGL with a thickness of 12 nm is provided.

[0207] A p-type charge generation layer PCGL and a second hole transport layer HTL2 are sequentially disposed on an n-type charge generation layer NCGL. The total thickness of the p-type charge generation layer PCGL and the second hole transport layer HTL2 is 52 nm. The main bodies of the p-type charge generation layer PCGL and the second hole transport layer HTL2 may include the same hole transport material. The p-type charge generation layer PCGL may also include a p-type dopant.

[0208] A first optical compensation layer R'HTL is formed on the second hole transport layer HTL2 of the first sub-pixel RSP. The first optical compensation layer R'HTL contains a hole transport material and has a thickness of 54 nm. A second red emitting layer REML2, comprising a red dopant RD, a hole transport host, and an electron transport host, is formed on the first optical compensation layer R'HTL with a thickness of up to 36 nm.

[0209] A second optical compensation layer G'HTL is formed on the second hole transport layer HTL2 of the second sub-pixel GSP. The second optical compensation layer G'HTL is formed of a hole transport material and has a thickness of 7 nm. A second green emitting layer GEML2, comprising a green dopant GD, a hole transport host, and an electron transport host, is formed on the second optical compensation layer G'HTL and has a thickness of 30 nm.

[0210] A second blue emitting layer BEML2 is formed on the electron blocking layer EBL of the third sub-pixel BSP, comprising sequentially stacked first to third sub-emitting layers BEML2a, BEML2b, and BEML2c. In Experimental Example 7 EX7, the first sub-emitting layer BEML2a comprises a first blue host BH1 and a blue dopant BD, and has a thickness of 5 nm. Experimental Examples 8 EX8 and 9 EX9 differ in that the thicknesses of the first sub-emitting layer BEML2a are 7 nm and 9 nm, respectively.

[0211] In the first to third sub-pixels RSP, GSP and BSP, a second hole blocking layer HBL2 with a thickness of 5 nm is provided on each of the second color emitting layers REML2, GEML2 and BEML2, an electron transport layer ETL with a thickness of 30 nm is provided, and an electron injection layer EIL with a thickness of 2 nm is provided.

[0212] A cathode CAT with a thickness of 15 nm was formed on the electron injection layer EIL, and then a capping layer CPL with a thickness of 65 nm was formed.

[0213] Meanwhile, in the first stack S1 and the second stack S2, the first sub-pixel RSP and the second sub-pixel GSP have a relatively longer resonant distance between the anode AND and the cathode CAT compared to the third sub-pixel BSP, thus exhibiting microcavity characteristics. Furthermore, the first sub-pixel RSP and the second sub-pixel GSP have a first optical compensation layer R'HTL and a second optical compensation layer G'HTL to ensure red cavity characteristics and green cavity characteristics, respectively. The first optical compensation layer R'HTL and the second optical compensation layer G'HTL are disposed on the second stack S2, which is closer to the viewer's eye and therefore less sensitive to changes in viewing angle.

[0214] Figure 9 The location of the composite region is shown, depending on the thickness of the first sub-emitting layer in the first blue emitting stack in Experimental Examples 4 to 6. Figure 10 The location of the composite region is shown, depending on the thickness of the first sub-emitting layer in the second blue emitting stack in Experimental Examples 7 to 9.

[0215] In Table 2 and Figure 9 In experimental examples 4 to 6 EX4, EX5, and EX6, the thicknesses of the first to third sub-emissive layers of the second blue emitting layer BEML2 are 7 nm, 8 nm, and 3 nm, respectively. (See Table 3 and...) Figure 10 In experimental examples 7 to 9 EX7, EX8 and EX9, the thicknesses of the first to third sub-emitting layers of the first blue emitting layer BEML1 are 7 nm, 8 nm and 3 nm, respectively.

[0216] Table 2 shows the device performance depending on the thickness variation of the first sub-emitting layer BEML1a of the first blue emitting layer BEML1 and the second blue emitting layer BEML2, where the thicknesses of the first sub-emitting layer to the third sub-emitting layer are 7 nm, 8 nm and 3 nm respectively, and Table 3 shows the device performance depending on the thickness variation of the first sub-emitting layer BEML2a of the second blue emitting layer BEML2.

[0217] [Table 2]

[0218]

[0219] [Table 3]

[0220]

[0221] As shown in Table 2 and Figure 9In Experiment Examples 4 to 6, EX4, EX5, and EX6, when the thickness of the first sub-emitting layer BEML1a in the first blue emitting layer BEML1 is changed, in Experiment Example 4, EX4, where the thickness of the first sub-emitting layer BEML2a is less than that of the second emitting layer BEML2, a fully recombination region is formed in the first sub-emitting layer BEML1a, and the effects of reduced driving voltage, maximum efficiency, and increased lifetime can be ensured. This is because, in the first stack S1, the first blue emitting layer BEML1 is in contact with a common layer for hole transport, which is an electron blocking layer with low hole mobility. By controlling the movement speed of holes transported to the first blue emitting layer BEML1 using the electron blocking layer, the recombination region in the thin first sub-emitting layer BEML1a can be pushed to a predetermined extent, and thus the recombination region is set in the first sub-emitting layer BEML1a of the first blue emitting layer BEML1, rather than being locally located at a specific interface.

[0222] Table 3 and Figure 10 Comparing experimental examples 7 to 9 EX7, EX8 and EX9, it can be seen that experimental example 8 EX8, in which the thickness of the first sub-emitting layer BEML2a in the second blue emitting layer BEML2 is 7 nm, exhibits excellent voltage, efficiency and lifetime characteristics.

[0223] From Tables 2 and 3 and Figure 9 and Figure 10 It can be seen that in Experimental Example 4 EX4, voltage, efficiency and lifetime are improved under the following conditions: the second sub-emitting layer BEML1b in the first blue emitting layer BEML1 is the thickest and the third sub-emitting layer BEML1c is the thinnest, the second sub-emitting layer BEML2b in the second blue emitting layer BEML2 is the thickest and the third sub-emitting layer BEML2c is the thinnest, and the thickness of the first sub-emitting layer BEML2a in the second blue emitting layer BEML2 is greater than the thickness of the first sub-emitting layer BEML1a in the first blue emitting layer BEML2.

[0224] Meanwhile, Experimental Example 5 EX5 in Table 2 and Experimental Example 8 EX8 in Table 3 have the same configuration.

[0225] In this paper, the viewing angle characteristics are determined by optical simulation while varying the thicknesses of the first sub-emitting layers BEML1a and BEML2a in the first blue emitting layer BEML1 of the first stack S1 and the second blue emitting layer BEML of the second stack S2.

[0226] In addition to Experimental Examples 4 EX4 to 9 EX9 described in Tables 2 and 3, Experimental Example 10 EX10, in which the thickness of the first sub-emitting layer BEML1a of the first blue emitting layer BEML1 is 3 nm, and Experimental Example 11 EX11, in which the thickness of the first sub-emitting layer BEML2a of the second blue emitting layer BEML2 is 3 nm, is also added.

[0227] Figure 11 The viewing angle characteristics obtained by changing the thickness of the first sub-emitting layer of the first blue emitting layer are shown when the cathode is formed by AgMg with a thickness of 15 nm and when the cathode is formed by IZO with a thickness of 20 nm. Figure 12 The viewing angle characteristics obtained by changing the thickness of the first sub-emitting layer of the second blue emitting layer are shown when the cathode is formed with AgMg at a thickness of 15 nm and when the cathode is formed with IZO at a thickness of 20 nm.

[0228] Figure 11 The diagram shows that the thickness of the first sub-emitting layer BEML1a of the first blue emitting layer BEML1 changes to 3 nm, 5 nm, 7 nm, and 9 nm, and the second sub-emitting layer BEML1b and the third sub-emitting layer BEML1c of the first blue emitting layer BEML1 have common thicknesses of 8 nm and 3 nm, respectively. Furthermore, the second blue emitting layer BEML2 has first to third sub-emitting layers BEML2a, BEML2b, and BEML2c with thicknesses of 7 nm, 8 nm, and 3 nm, respectively.

[0229] In each experimental example, viewing angle characteristics were evaluated at 0° and 45° angles. Viewing angle characteristics were evaluated by changes in the white coordinates when the light-emitting devices of the first to third sub-pixels RSP, GSP, and BSP were turned on. An upward shift in the color coordinates indicated a greenish color change, while a downward shift indicated a bluish color change.

[0230] Regarding the thickness variation of the first sub-emitting layer BEML1a of the first blue emitting layer BEML1, it can be seen that the blue color variation of the cathode, which is a light-transmitting electrode (e.g., IZO), is greater than that of the cathode, which is a light-transmitting electrode (e.g., AgMg).

[0231] Figure 12The thickness of the first sub-emitting layer BEML2a of the second blue emitting layer BEML2 varies to 3 nm, 5 nm, 7 nm, and 9 nm, and the second sub-emitting layer BEML2b and the third sub-emitting layer BEML2c of the second blue emitting layer BEML2 have common thicknesses of 8 nm and 3 nm, respectively. Furthermore, the first blue emitting layer BEML1 has first sub-emitting layers BEML1a, BEML1b, and BEML1c with thicknesses of 7 nm, 8 nm, and 3 nm, respectively.

[0232] from Figure 12 It can be seen that the thickness variation of the first sub-emissive layer BEML2a of the second blue emitting layer BEML2 leads to... Figure 11 The thickness of the first sub-emitting layer BEML1a of the first blue emitting layer BEML1 varies with the color.

[0233] From a viewing angle perspective, when the thickness of the first sub-emitting layers BEML1a and BEML2a of each of the first blue emitting layer BEML1 and the second blue emitting layer BEML2 is minimized or reduced, the color change caused by the viewing angle variation in the light-emitting cathode (IZO 20 nm) is minimized or reduced. However, in the light-emitting display device according to the embodiments of this disclosure, in addition to the viewing angle, driving voltage, efficiency, and lifetime characteristics can also be considered together to make the second blue emitting layer BEML2 of the second stack S2 thicker than the first blue emitting layer BEML1.

[0234] Figure 13 The viewing angle characteristics obtained by changing the thickness of the first sub-emitting layer of the first blue emitting layer are shown when the cathode is formed by AgMg with a thickness of 15 nm and when the cathode is formed by ITO with a thickness of 20 nm. Figure 14 The viewing angle characteristics obtained by changing the thickness of the first sub-emitting layer of the second blue emitting layer are shown when the cathode is formed by AgMg with a thickness of 15 nm and when the cathode is formed by ITO with a thickness of 20 nm.

[0235] Reference Figure 13 and Figure 14 The viewing angle characteristics when ITO is used as the cathode are similar to those described above. Figure 11 and Figure 12 Viewing angle characteristics when IZO is used as a cathode.

[0236] Regarding viewing angle, when the thickness of each of the first blue emitting layer BEML1 and the second blue emitting layer BEML2 is minimized or reduced, the color change depending on the viewing angle is minimized or reduced. However, in the light-emitting display device according to the embodiments of this disclosure, in addition to viewing angle, driving voltage, efficiency, and lifetime characteristics are also considered to ensure that the thickness of the second blue emitting layer BEML2 is at a predetermined level relative to the first blue emitting layer BEML1, so that blue efficiency and lifetime can be ensured in the third sub-pixel emitting blue, and the driving voltage can be set to a predetermined level or lower.

[0237] Perform the experiments in Table 4 to evaluate the difference in blue dopant concentration in the first sub-emitting layers BEML1a / BEML1b / BEML1c of the first blue emitting layer BEML1 in the first stack S1 and the first sub-emitting layers BEML2a / BEML2b / BEML2c of the second blue emitting layer BEML2 in the second stack S2.

[0238] [Table 4]

[0239]

[0240] As shown in Table 4, when the doping concentration of the first blue dopant BD1 in the first blue light-emitting layer BEML1 of the first stack S1 is greater than the doping concentration of the second blue dopant BD2 in the second blue light-emitting layer BEML2, the driving voltage is reduced and the lifetime is increased.

[0241] The optical simulation used in this paper was the "1D Simulation (LG Display)" program.

[0242] In the following, another embodiment of the light-emitting display device according to the present disclosure will be described.

[0243] Figure 15 This is a cross-sectional view showing a light-emitting display device according to another embodiment of the present disclosure.

[0244] according to Figure 15 2000 light-emitting display device and Figure 2 The difference in the light-emitting display device 1000 shown is the configuration of the dam 220 and the connection structure between the auxiliary electrode 210 and the cathode 126.

[0245] The dam 220 may include a first light-shielding dam 221 and a second light-transmitting dam 222. Furthermore, the dam 220 between adjacent sub-pixels RSP, GSP, and BSP may have a trench 220T extending from the surface to a predetermined depth, allowing lateral leakage current to be minimized or reduced by lengthening the lateral paths of adjacent sub-pixels RSP, GSP, and BSP. In some cases, at least a portion of the first common layer CML1 and the second common layer CML2 may be disconnected within the trench 220T. In this case, the lateral leakage current prevention effect is further improved.

[0246] In some cases, the auxiliary electrode can be disposed on the lower side of the trench 220T, which can be deep enough to expose the auxiliary electrode 210. The cathode 126 can be connected to the auxiliary electrode 210 within the trench 220T, thereby providing a cathode 126 connection area within the display area AA where sub-pixels RSP, GSP, and BSP are disposed, and reducing the resistance of the cathode 126. Specifically, when the cathode 126 includes a light-transmitting electrode, the resistance of the cathode 126 can be reduced by connecting the auxiliary electrode 210 to the cathode 126, thereby homogenizing the voltage characteristics of the cathode 126 in the display area AA and homogenizing the brightness characteristics of the display area AA.

[0247] The dam 220 may also include a spacer 223 having a greater height than, for example, the second dam 222, such that the spacer 223 can protect the lower configuration against the deposition mask used when forming the intermediate layers REL, GEL and BEL of each sub-pixel RSP, GSP and BSP.

[0248] At the same time, Figure 15 In the light-emitting display device 2000, the first sub-pixel to the third sub-pixel RSP, GSP, BSP have a configuration in which at least two light-emitting stacks S1 and S2 are stacked, as shown in reference. Figures 1 to 5 As described. Each of the first to third sub-pixels RSP, GSP, and BSP may include a first common layer CML1, color emitting pattern portions RS, GS, and BS, and a second common layer CML2 located between the anode (122, AND) and cathode (126, CAT) of the light-emitting device. The first common layer CML1 and the second common layer CML2 may be removed at the portion where the cathode 126 and the auxiliary electrode 210 are connected.

[0249] Each color-emitting pattern portion RS, GS, BS includes a first color-emitting layer REML1, GEML1, and BEML1, a third common layer CML3, and a second color-emitting layer REML2, GEML2, and BEML2. The first color-emitting layer REML1, GEML1, and BEML1, as well as the second color-emitting layer REML2, GEML2, and BEML2, have shapes that are independently set in the first to third sub-pixels RSP, GSP, and BSP.

[0250] like Figure 3 , Figure 7 and Figure 8 As shown, the first blue emitting layer BEML1 disposed in the third sub-pixel BSP includes first sub-emitting layers BEML1a, BEML1b, and BEML1c that alternately have different main bodies BH1 and BH2, and the second blue emitting layer BEML2 includes first sub-emitting layers BEML2a, BEML2b, and BEML2c that alternately have different main bodies BH3 and BH4. The first sub-emitting layers BEML1 and BEML2 can be stacked emitting layers, such that the second sub-emitting layers BEML1b and BEML2b, as intermediate layers, can be the thickest, and the third sub-emitting layers BEML1c and BEML2c, as the last layers, can be the thinnest. Furthermore, by ensuring that the thickness of the first sub-emitting layer BEML2a, which serves as the second blue emitting layer BEML2, is greater than the thickness of the first sub-emitting layer BEML1a of the first blue emitting layer BEML1, which is in contact with the relatively slow electron blocking layer EBL, high efficiency and long lifetime can be achieved without significantly changing the driving voltage required for blue light emission in the multi-stacked structure, while also improving viewing angle characteristics.

[0251] The light-emitting display device according to the embodiments of the present disclosure has a light-emitting device including multiple light-emitting layers, which can improve efficiency, reduce driving voltage and increase lifespan in at least some sub-pixels.

[0252] As is apparent from the above description, the light-emitting device display apparatus according to embodiments of the present disclosure includes a plurality of light-emitting layers, each light-emitting layer being disposed in a first light-emitting stack and a second light-emitting stack, the first light-emitting stack and the second light-emitting stack overlapping each other in at least a portion of sub-pixels, wherein the thickness relationship between the light-emitting layers is defined such that the recombination region of holes and electrons is spaced apart from the interface between the light-emitting layer and the common layer, thereby preventing a reduction in lifetime due to the accumulation of charge carriers or excitons at the interface of the light-emitting layers.

[0253] Embodiments of this disclosure provide a light-emitting display device in which each stacked plurality of light-emitting layers includes a plurality of sub-light-emitting layers with different bodies, such that the triplet-triplet annihilation TTA efficiency in the second sub-light-emitting layer, which is the thickest layer, is enhanced, and thus the exciton utilization and luminous efficiency within the light-emitting layer are enhanced.

[0254] Embodiments of this disclosure provide a light-emitting display device in which, in a multi-emitting layer, a first sub-emitting layer adjacent to a hole transport common layer includes a first body having a small HOMO energy level difference with a dopant, and a second sub-emitting layer includes a second body having a HOMO energy level lower than that of the first body, thereby facilitating hole transfer from the first sub-emitting layer to the second sub-emitting layer and preventing holes from being trapped at the interface between the hole transport common layer and the emitting layer.

[0255] Embodiments of this disclosure provide a light-emitting display device that includes multiple light-emitting stacks in each sub-pixel in a top-emitting manner to improve light-emitting efficiency, and minimizes or reduces color shift due to viewing angle changes in the structure having multiple stacked light-emitting layers, thereby providing uniform visual perception regardless of viewing angle changes.

[0256] Embodiments of this disclosure provide a light-emitting display device that exhibits improved lifetime due to differences in dopant concentrations included in differently stacked light-emitting layers.

[0257] The light-emitting devices and light-emitting display devices according to embodiments of this disclosure can improve the efficiency of the light-emitting layer, thereby reducing the driving voltage and increasing the lifetime. Therefore, the light-emitting devices and light-emitting display devices are significant for sustainable applications and can achieve ESG (Environmental, Social, and Governance) objectives.

[0258] The effects achievable through this disclosure are not limited to those mentioned above, and various other effects may be disclosed directly or implicitly in the above detailed description of this disclosure.

[0259] A light-emitting display device according to one embodiment of the present disclosure may include: a substrate, the substrate including a first sub-pixel, a second sub-pixel and a third sub-pixel; a transistor at each of the first to third sub-pixels on the substrate; a planarization layer on the transistor; and a first light-emitting device, a second light-emitting device and a third light-emitting device on the planarization layer, the first light-emitting device, the second light-emitting device and the third light-emitting device emitting red light, green light and blue light respectively at the first to third sub-pixels; and an encapsulation layer above the first to third light-emitting devices.

[0260] Each of the first to third light-emitting devices may include an anode and a cathode facing each other, and a charge generation layer between the anode and the cathode.

[0261] The third light-emitting device may include a first blue light-emitting stack and a second blue light-emitting stack. The first blue light-emitting stack includes a first blue light-emitting layer between the anode and the charge generation layer, and the second blue light-emitting stack includes a second blue light-emitting layer between the charge generation layer and the cathode. Each of the first and second blue light-emitting layers may include multiple sub-light-emitting layers. The thickness of the second blue light-emitting layer may be greater than the thickness of the first blue light-emitting layer.

[0262] In a light-emitting display device according to one embodiment of the present disclosure, the sub-light-emitting layers of the first blue light-emitting layer and the second blue light-emitting layer may each have different bodies at vertically adjacent interfaces.

[0263] Each of the first blue emitting layer and the second blue emitting layer may include a first sub-emitting layer to a third sub-emitting layer.

[0264] The first sub-emitting layer and the third sub-emitting layer of the first blue emitting layer may include a first blue host and a first blue dopant, and the second sub-emitting layer of the first blue emitting layer may include a second blue host and a first blue dopant having a triplet energy level lower than that of the first blue host.

[0265] The first and third sub-emitting layers of the second blue emitting layer may include a third blue host and a second blue dopant, and the second sub-emitting layer of the second blue emitting layer may include a fourth blue host and a second blue dopant having a triplet energy level lower than that of the third blue host.

[0266] The HOMO level of the first blue dopant can be higher than the HOMO level of each of the first and second blue bodies.

[0267] The HOMO level of the second blue dopant can be higher than the HOMO levels of each of the third and fourth blue dopants.

[0268] In a light-emitting display device according to one embodiment of the present disclosure, among the first to third sub-light-emitting layers of the first blue light-emitting layer, the second sub-light-emitting layer may be the thickest, and the third sub-light-emitting layer may be the thinnest. Similarly, among the first to third sub-light-emitting layers of the second blue light-emitting layer, the second sub-light-emitting layer may be the thickest, and the third sub-light-emitting layer may be the thinnest.

[0269] In a light-emitting display device according to one embodiment of the present disclosure, the thickness of the first sub-light-emitting layer in the second blue light-emitting layer may be two to three times the thickness of the third sub-light-emitting layer.

[0270] In a light-emitting display device according to one embodiment of the present disclosure, the thickness of the first sub-light-emitting layer in the first blue light-emitting layer may be greater than the thickness of the third sub-light-emitting layer, and may not exceed twice the thickness of the third sub-light-emitting layer.

[0271] In a light-emitting display device according to one embodiment of the present disclosure, the first sub-light-emitting layer of the first blue light-emitting layer may be thinner than the first sub-light-emitting layer of the second blue light-emitting layer.

[0272] In a light-emitting display device according to one embodiment of the present disclosure, the thickness of the first sub-light-emitting layer of the second blue light-emitting layer may be greater than the thickness of the first sub-light-emitting layer of the first blue light-emitting layer, and not exceed 1.5 times the thickness of the first sub-light-emitting layer of the first blue light-emitting layer.

[0273] In a light-emitting display device according to one embodiment of the present disclosure, the concentration of the first blue dopant in the first blue light-emitting layer may be greater than the concentration of the second blue dopant in the second blue light-emitting layer.

[0274] In a light-emitting display device according to one embodiment of the present disclosure, the first light-emitting device may include a first red light-emitting layer between the anode and the charge-generating layer and a second red light-emitting layer between the charge-generating layer and the cathode, and the second light-emitting device may include a first green light-emitting layer between the anode and the charge-generating layer and a second green light-emitting layer between the charge-generating layer and the cathode. Furthermore, the first red light-emitting layer may overlap with the second red light-emitting layer and may be horizontally spaced from the first blue light-emitting layer.

[0275] In a light-emitting display device according to one embodiment of the present disclosure, a first red light-emitting layer, a first green light-emitting layer and a first blue light-emitting layer may contact an electron blocking layer disposed together at a first sub-pixel to a third sub-pixel, and a second blue light-emitting layer may contact a hole transport layer.

[0276] The light-emitting display device may further include a first optical compensation layer between the hole transport layer and the second red light-emitting layer, and a second optical compensation layer between the hole transport layer and the second green light-emitting layer.

[0277] A light-emitting display device according to one embodiment of the present disclosure may further include: a first common layer between the anode and the first blue light-emitting layer; and a second common layer between the second blue light-emitting layer and the cathode.

[0278] The first common layer and the second common layer can extend horizontally and continuously across the first light-emitting device and the second light-emitting device.

[0279] In a light-emitting display device according to one embodiment of the present disclosure, a first blue light-emitting layer may contact an electron blocking layer on the surface of the first blue light-emitting layer facing the anode, and a second blue light-emitting layer may contact a hole transport layer on the surface of the second blue light-emitting layer facing the charge generation layer.

[0280] In a light-emitting display device according to one embodiment of the present disclosure, the hole mobility of the hole transport layer can be 1 to 3 orders of magnitude greater than the hole mobility of the electron blocking layer.

[0281] According to one embodiment of the present disclosure, the light-emitting display device may further include a capping layer between the cathode and the encapsulation layer.

[0282] The capping layer can be thicker than the cathode.

[0283] In a light-emitting display device according to one embodiment of the present disclosure, each of the first light-emitting device, the second light-emitting device, and the third light-emitting device may have a light-emitting area defined by a ridge on a planarization layer.

[0284] Each of the first blue luminescent layer and the second blue luminescent layer may have an edge that overlaps with the embankment.

[0285] A light-emitting display device according to one embodiment of the present disclosure may include a touch electrode on an encapsulation layer. The touch electrode may overlap with the encapsulation layer.

[0286] The light-emitting display device according to one embodiment of the present disclosure may further include a color filter on the touch electrode. The color filter may include a red color filter overlapping with a first light-emitting device, a green color filter overlapping with a second light-emitting device, and a blue color filter overlapping with a third light-emitting device.

[0287] According to one embodiment of the present disclosure, the light-emitting display device may further include a plurality of inorganic insulating layers between the substrate and the thin-film transistor.

[0288] In a light-emitting display device according to one embodiment of the present disclosure, the first blue light-emitting layer may include a boron-based fluorescent dopant having an emission peak at a wavelength of 420 nm to 495 nm.

[0289] In a light-emitting display device according to one embodiment of the present disclosure, the charge generation layer may include an n-type charge generation layer adjacent to a first blue light-emitting stack and a p-type charge generation layer adjacent to a second blue light-emitting stack.

[0290] In a light-emitting display device according to one embodiment of the present disclosure, the dam may include a light-shielding dam and a light-transmitting dam.

[0291] According to one embodiment of the present disclosure, the light-emitting display device may further include an auxiliary electrode electrically connected to the cathode via a groove disposed in the embankment.

[0292] In a light-emitting display device according to one embodiment of the present disclosure, the anode may include a reflective electrode having a laminated structure of an indium tin oxide (ITO) and an APC (Ag / Pd / Cu) alloy.

[0293] A light-emitting display device according to one embodiment of the present disclosure may include: a substrate having at least a blue sub-pixel; and a light-emitting device at the blue sub-pixel, the light-emitting device including an anode, a cathode, and a first blue light-emitting stack and a second blue light-emitting stack separated by a charge generation layer. Each of the first blue light-emitting stack and the second blue light-emitting stack may include a first sub-light-emitting layer, a second sub-light-emitting layer, and a third sub-light-emitting layer. The second sub-light-emitting layer may include a body having a triplet energy level lower than that of the body of the first sub-light-emitting layer to induce delayed fluorescence via triplet-triplet annihilation. The thickness of the second blue light-emitting stack may be greater than the thickness of the first blue light-emitting stack.

[0294] In a light-emitting display device according to one embodiment of the present disclosure, a first sub-light-emitting layer may be configured to be closer to the anode than a second sub-light-emitting layer and a third sub-light-emitting layer, and the recombination region of holes and electrons is entirely located within the first sub-light-emitting layer.

[0295] In a light-emitting display device according to one embodiment of the present disclosure, the first sub-light-emitting layer and the third sub-light-emitting layer may include the same body material.

[0296] In a light-emitting display device according to one embodiment of the present disclosure, a first blue light-emitting stack may be in contact with an electron blocking layer, the hole mobility of which is at least 10 times lower than that of a hole transport layer in contact with a second blue light-emitting stack.

[0297] In a light-emitting display device according to one embodiment of the present disclosure, the dopant concentration in the first blue light-emitting stack may be higher than the dopant concentration in the second blue light-emitting stack.

[0298] In a light-emitting display device according to one embodiment of the present disclosure, the cathode may include a transparent conductive material and may be electrically connected to an auxiliary electrode, which is disposed on the same layer as the connection electrode of the transistor of the light-emitting device.

[0299] Although the present disclosure has been described above, it is not limited to the above-described embodiments and drawings, and it will be apparent to those skilled in the art that various changes, modifications and alterations can be made without departing from the technical spirit of the present disclosure.

Claims

1. A light-emitting display device, comprising: A substrate, the substrate comprising a first sub-pixel, a second sub-pixel, and a third sub-pixel; Transistors located at the first sub-pixel to the third sub-pixel on the substrate, respectively; The planarization layer on the transistor; The first light-emitting device, the second light-emitting device, and the third light-emitting device on the planarization layer are configured to emit red light, green light, and blue light respectively at the first sub-pixel to the third sub-pixel; and The encapsulation layer above the first light-emitting device to the third light-emitting device, wherein: Each of the first to the third light-emitting devices includes an anode and a cathode facing each other, and a charge-generating layer between the anode and the cathode. The third light-emitting device includes a first blue light-emitting stack and a second blue light-emitting stack. The first blue light-emitting stack includes a first blue light-emitting layer between the anode and the charge generation layer, and the second blue light-emitting stack includes a second blue light-emitting layer between the charge generation layer and the cathode. Each of the first blue emitting layer and the second blue emitting layer includes multiple sub-emitting layers, and The thickness of the second blue emitting layer is greater than the thickness of the first blue emitting layer.

2. The light-emitting display device according to claim 1, wherein, The sub-emitting layers of the first blue emitting layer and the sub-emitting layers of the second blue emitting layer have different bodies at the vertically adjacent interface.

3. The light-emitting display device according to claim 1, wherein, Each of the first blue emitting layer and the second blue emitting layer includes a first sub-emitting layer to a third sub-emitting layer. The first sub-emitting layer and the third sub-emitting layer of the first blue emitting layer include a first blue host and a first blue dopant. The second sub-emitting layer of the first blue emitting layer includes a second blue host having a triplet energy level lower than that of the first blue host and the first blue dopant. Wherein, the first sub-emitting layer and the third sub-emitting layer of the second blue emitting layer include a third blue host and a second blue dopant, and The second sub-emitting layer of the second blue emitting layer includes a fourth blue host having a triplet energy level lower than that of the third blue host and the second blue dopant.

4. The light-emitting display device according to claim 3, wherein, The triplet energy level of the first blue dopant is higher than the triplet energy levels of each of the first blue host and the second blue host.

5. The light-emitting display device according to claim 3, wherein, The first blue body comprises a pyrene derivative, and the second blue body comprises an anthracene derivative.

6. The light-emitting display device according to claim 3, wherein, The highest occupied molecular orbital HOMO level of the first blue dopant is higher than the HOMO levels of each of the first and second blue substrates, and The HOMO level of the second blue dopant is higher than the HOMO level of each of the third and fourth blue bodies.

7. The light-emitting display device according to claim 3, wherein, Among the first sub-emitting layers to the third sub-emitting layer of the first blue emitting layer, the second sub-emitting layer is the thickest, and the third sub-emitting layer is the thinnest. Among the first to the third sub-emissive layers of the second blue emissive layer, the second sub-emissive layer is the thickest, and the third sub-emissive layer is the thinnest.

8. The light-emitting display device according to claim 7, wherein, The thickness of the first sub-emissive layer in the second blue emissive layer is two to three times the thickness of the third sub-emissive layer.

9. The light-emitting display device according to claim 8, wherein, In the first blue light-emitting layer, the thickness of the first sub-light-emitting layer is greater than the thickness of the third sub-light-emitting layer, but does not exceed twice the thickness of the third sub-light-emitting layer.

10. The light-emitting display device according to claim 8, wherein, The first sub-emitting layer of the first blue emitting layer is thinner than the first sub-emitting layer of the second blue emitting layer.

11. The light-emitting display device according to claim 3, wherein, The thickness of the first sub-emitting layer of the second blue emitting layer is greater than the thickness of the first sub-emitting layer of the first blue emitting layer, but does not exceed 1.5 times the thickness of the first sub-emitting layer of the first blue emitting layer.

12. The light-emitting display device according to claim 3, wherein, The concentration of the first blue dopant in the first blue light-emitting layer is greater than the concentration of the second blue dopant in the second blue light-emitting layer.

13. The light-emitting display device according to claim 1, wherein: The first light-emitting device includes a first red light-emitting layer between the anode and the charge-generating layer, and a second red light-emitting layer between the charge-generating layer and the cathode. The second light-emitting device includes a first green light-emitting layer between the anode and the charge-generating layer, and a second green light-emitting layer between the charge-generating layer and the cathode. The first red emitting layer overlaps with the second red emitting layer and is horizontally spaced from the first blue emitting layer.

14. The light-emitting display device according to claim 13, wherein, The first red light-emitting layer, the first green light-emitting layer, and the first blue light-emitting layer are in contact with an electron blocking layer that is disposed together at the first sub-pixel to the third sub-pixel. The second blue luminescent layer is in contact with the hole transport layer, and The light-emitting display device further includes a first optical compensation layer between the hole transport layer and the second red light-emitting layer, and a second optical compensation layer between the hole transport layer and the second green light-emitting layer.

15. The light-emitting display device according to claim 1, further comprising: The first common layer between the anode and the first blue emitting layer; as well as A second common layer between the second blue emitting layer and the cathode. The first common layer and the second common layer extend horizontally and continuously across the first light-emitting device and the second light-emitting device.

16. The light-emitting display device according to claim 1, wherein, The first blue emitting layer contacts an electron blocking layer on the surface of the first blue emitting layer facing the anode, and the second blue emitting layer contacts a hole transport layer on the surface of the second blue emitting layer facing the charge generating layer.

17. The light-emitting display device according to claim 16, wherein, The hole mobility of the hole transport layer is 1 to 3 orders of magnitude greater than that of the electron blocking layer.

18. The light-emitting display device according to claim 1, further comprising a capping layer between the cathode and the encapsulation layer, in, The capping layer is thicker than the cathode.

19. The light-emitting display device according to claim 1, wherein, Each of the first, second, and third light-emitting devices has a light-emitting area defined by the ridges on the planarization layer, and Each of the first blue luminescent layer and the second blue luminescent layer has an edge that overlaps with the embankment.

20. The light-emitting display device according to claim 19, further comprising a touch electrode on the encapsulation layer, in, The touch electrode overlaps with the embankment.

21. The light-emitting display device according to claim 20, further comprising a color filter on the touch electrode. in, The color filter includes a red color filter that overlaps with the first light-emitting device, a green color filter that overlaps with the second light-emitting device, and a blue color filter that overlaps with the third light-emitting device.

22. The light-emitting display device according to claim 1, further comprising a plurality of inorganic insulating layers between the substrate and the transistor.

23. The light-emitting display device according to claim 1, wherein, The first blue emitting layer includes a boron-based fluorescent dopant having an emission peak at wavelengths from 420 nm to 495 nm.

24. The light-emitting display device according to claim 19, wherein, The dikes include both shade dikes and light-transmitting dikes.

25. The light-emitting display device according to claim 19, further comprising an auxiliary electrode electrically connected to the cathode via a groove disposed in the embankment.

26. The light-emitting display device according to claim 25, further comprising: The first common layer between the anode and the first blue emitting layer; as well as A second common layer between the second blue emitting layer and the cathode. Wherein, each of the first common layer and the second common layer is disconnected at the connection between the auxiliary electrode and the cathode.

27. The light-emitting display device according to claim 24, wherein, The embankment includes a spacer with a greater height than the light-transmitting embankment.

28. A light-emitting display device, comprising: A substrate with at least blue sub-pixels; as well as The light-emitting device at the blue sub-pixel includes an anode, a cathode, and a first blue light-emitting stack and a second blue light-emitting stack separated by a charge generation layer between the anode and the cathode; Each of the first blue emitting stack and the second blue emitting stack includes a first sub-emitting layer, a second sub-emitting layer, and a third sub-emitting layer. Specifically, for each of the first blue emitting stack and the second blue emitting stack, the second sub-emitting layer includes a host having a triplet energy level lower than that of the host of the first sub-emitting layer to induce delayed fluorescence, and The thickness of the second blue light-emitting stack is greater than the thickness of the first blue light-emitting stack.

29. The light-emitting display device according to claim 28, wherein, The delayed fluorescence is induced by triplet-triplet annihilation or triplet-triplet fusion.

30. The light-emitting display device according to claim 28, wherein, For each of the first blue emitting stack and the second blue emitting stack, the thickness of the second sub-emitting layer is greater than the thickness of each of the first sub-emitting layer and the third sub-emitting layer.

31. The light-emitting display device according to claim 28, in, The first sub-emitting layer is positioned closer to the anode than the second and third sub-emitting layers, and the recombination region of holes and electrons is entirely located within the first sub-emitting layer. The first sub-light-emitting layer and the third sub-light-emitting layer both contain the same main material.

32. The light-emitting display device according to claim 28, wherein, The first blue light-emitting stack is in contact with the electron blocking layer, wherein the hole mobility of the hole transport layer in contact with the second blue light-emitting stack is at least an order of magnitude greater than the hole mobility of the electron blocking layer.

33. The light-emitting display device according to claim 28, wherein, The cathode comprises a transparent conductive material and is electrically connected to an auxiliary electrode, which is disposed on the same layer as the connection electrode of the transistor of the light-emitting device.

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