Light-emitting display device

Abstract

A light emitting display device includes: a first electrode; a first electron transport layer disposed on the first electrode; a light emitting layer disposed on the first electron transport layer; a hole transport layer disposed on the light emitting layer; a hole injection layer disposed on the hole transport layer; a second electrode disposed on the hole injection layer; and a reflective member spaced apart from the first electron transport layer, in which the reflective member includes an inclined surface that reflects incident light toward the first electron transport layer.

Description

[0001] This application claims priority to Korean Patent Application No. 10-2023-0149043 filed on November 1, 2023, and all benefits accruing therefrom, the disclosure of which is incorporated herein in its entirety by reference. TECHNICAL FIELD

[0002] The present disclosure relates to a light emitting display apparatus and a method of manufacturing the same. BACKGROUND

[0003] Unlike bulk materials, nanoparticles have physical properties (e.g., band gap, melting point, etc.) referred to as intrinsic properties of a material that can vary depending on the particle size.

[0004] Semiconductor nanocrystals, also referred to as quantum dots, for example, can emit light having a wavelength corresponding to the particle size of the quantum dot upon receiving light energy or electrical energy.

[0005] Accordingly, quantum dots can be used as light emitters that emit light having a predetermined wavelength, and these light emitters can be used in display apparatuses. SUMMARY

[0006] Embodiments of the present disclosure can provide improved performance of a light emitting display apparatus.

[0007] A light emitting display apparatus in an embodiment of the present disclosure includes a first electrode; a first electron transport layer on the first electrode; a light emitting layer on the first electron transport layer; a hole transport layer on the light emitting layer; a hole injection layer on the hole transport layer; a second electrode disposed on the hole injection layer; and a reflective member spaced apart from the first electron transport layer, wherein the reflective member includes an inclined surface that reflects incident light toward the first electron transport layer.

[0008] In an embodiment, the light emitting display apparatus can further include an intermediate insulating layer disposed under the first electrode and the reflective member.

[0009] In an embodiment, the light emitting display apparatus can further include a protrusion on the intermediate insulating layer, wherein the protrusion can include a first slope, the inclined surface of the reflective member can be disposed on the first slope, and an edge of the inclined surface of the reflective member can coincide with an upper surface of the first electron transport layer.

[0010] In an embodiment, the light emitting display apparatus can further include a protrusion on the intermediate insulating layer, wherein the protrusion can include an upper surface, a first slope, and a second slope, the second slope can be disposed opposite to the first slope, the reflective member can cover the upper surface and the second slope, the inclined surface of the reflective member can be disposed on the first slope, and an edge of the inclined surface of the reflective member can coincide with the upper surface of the first electron transport layer.

[0011] In an embodiment, the reflective member can have a refractive index higher than a refractive index of the intermediate insulating layer, and an upper surface of the reflective member can coincide with an upper surface of the first electron transport layer.

[0012] In an embodiment, the light emitting display device can further include a second electron transport layer disposed between the first electron transport layer and the light emitting layer, wherein the first electron transport layer can include ZnO, and the second electron transport layer can include ZnMgO.

[0013] The light emitting display device in an embodiment of the disclosure includes: a first light emitting device; a second light emitting device; and a reflective member disposed between the first light emitting device and the second light emitting device, wherein each of the first light emitting device and the second light emitting device includes: a first electrode; a first electron transport layer on the first electrode; a light emitting layer on the first electron transport layer; a hole transport layer on the light emitting layer; a hole injection layer on the hole transport layer; and a second electrode on the hole injection layer, wherein the reflective member includes: a first inclined surface that reflects incident light toward the first electron transport layer of the first light emitting device; and a second inclined surface that reflects incident light toward the first electron transport layer of the second light emitting device.

[0014] In an embodiment, the first electron transport layer of the first light emitting device and the first electron transport layer of the second light emitting device can have different thicknesses, and a height of an end of the first inclined surface is different from a height of an end of the second inclined surface.

[0015] In an embodiment, an end of the first inclined surface of the reflective member can coincide with an upper surface of the first electron transport layer of the first light emitting device, and an end of the second inclined surface of the reflective member can coincide with an upper surface of the first electron transport layer of the second light emitting device.

[0016] In an embodiment, the light emitting display device can further include an intermediate insulating layer disposed below the first light emitting device and the second light emitting device and the reflective member.

[0017] In an embodiment, the light emitting display device can further include first and second protrusions disposed on the intermediate insulating layer, wherein the first inclined surface of the reflective member can be disposed on a first inclined surface of the first protrusion, and the second inclined surface of the reflective member can be disposed on a second inclined surface of the second protrusion.

[0018] In an embodiment, the first protrusion can include an upper surface and a third inclined surface disposed opposite the first inclined surface, the second protrusion can include an upper surface and a fourth inclined surface disposed opposite the second inclined surface, and the reflective member can cover the upper surfaces, the third inclined surface, and the fourth inclined surface of the first and second protrusions.

[0019] In an embodiment, the reflective member can have a refractive index higher than a refractive index of the intermediate insulating layer, and an upper surface of the reflective member can coincide with an upper surface of the first electron transport layer.

[0020] In an embodiment, each of the first light emitting device and the second light emitting device can further include a second electron transport layer disposed between the first electron transport layer and the light emitting layer, the first electron transport layer can include ZnO, and the second electron transport layer can include ZnMgO.

[0021] In this way, in an embodiment of the present disclosure, the performance of the light emitting display apparatus can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] The above and other exemplary embodiments, advantages, and features of the present disclosure will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which:

[0023] Figure 1 is a schematic plan view of an embodiment of a light emitting display apparatus according to the present disclosure.

[0024] Figure 2 is Figure 1 is an exemplary cross-sectional view of a light emitting display apparatus taken along line II-II shown in FIG.

[0025] Figure 3 is a schematic cross-sectional view of a reflective member and a protrusion for explaining an operation of a light emitting display apparatus according to the present disclosure.

[0026] Figures 4 to 7 is a schematic cross-sectional view showing an embodiment of a method of manufacturing a light emitting display apparatus according to the present disclosure.

[0027] Figure 8 is a schematic cross-sectional view of an embodiment of a light emitting display apparatus according to the present disclosure.

[0028] Figure 9 is a schematic cross-sectional view of an embodiment of a light emitting display apparatus according to the present disclosure.

[0029] Figure 10 is a schematic cross-sectional view of an embodiment of a light emitting display apparatus according to the present disclosure. DETAILED DESCRIPTION

[0030] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present disclosure.

[0031] The present disclosure can be implemented in many different forms and is not limited to the embodiments described herein.

[0032] For the sake of clarity of the present disclosure, portions unrelated to the description have been omitted, and throughout the specification, the same or similar components are given the same reference numerals.

[0033] In addition, since the size and thickness of each portion shown in the drawings are arbitrarily determined for the sake of convenience of explanation, the present disclosure is not limited thereto.

[0034] In particular, in the drawings, the thickness is exaggerated and enlarged for the sake of clear representation of various layers and regions and convenience of explanation.

[0035] In addition, when a portion of a layer, film, region, or plate is referred to as "above" or "on" another portion, this includes not only a case in which it is "directly above" or "directly on" the other portion, but also a case in which there is another portion therebetween.

[0036] In contrast, when a portion is referred to as "just on top of" another portion, this means that there is no other portion therebetween.

[0037] In addition, "above" or "on" with reference to a portion means disposed "above" or "below" the reference portion, and does not necessarily mean disposed "above" or "on" the reference portion in a direction opposite to gravity.

[0038] In addition, throughout the specification, when a portion is referred to as "including" a specific element, this means that it can further include other elements, rather than excluding other elements, unless there is a specific statement to the contrary.

[0039] In addition, throughout the specification, when reference is made to "in a plan view", this means when the target portion is viewed from above, and when reference is made to "in a cross-section", this means when the cross-section of the target portion is cut perpendicularly and viewed from the side.

[0040] "About" or "approximately", as used herein, includes the stated value and means within an acceptable range of deviation for that particular value as determined by one of ordinary skill in the art, in view of the measurement being discussed and the error associated with measuring that particular quantity. For example, the term "about" can mean within one or more standard deviations, or within ±30%, ±20%, ±10%, ±5% of the stated value.

[0041] Next, embodiments of a light emitting display device of the present disclosure will be described in detail with reference to Figure 1 and Figure 2 A light emitting display device in embodiments of the present disclosure will be described in detail.

[0042] Figure 1 is a schematic plan view of an embodiment of a light emitting display device according to the present disclosure, and Figure 2 is Figure 1An exemplary cross-sectional view of the light emitting display apparatus shown in FIG. 1 taken along line II-II.

[0043] Referring to Figure 1 The light emitting display apparatus in embodiments of the present disclosure can include a plurality of light emitting elements (or light emitting devices) ED1, ED2, and ED3.

[0044] The light emitting devices ED1, ED2, and ED3 can include light emitting devices that exhibit three colors, such as a red light emitting device ED1, a green light emitting device ED2, and a blue light emitting device ED3.

[0045] The red light emitting device ED1, the green light emitting device ED2, and the blue light emitting device ED3 can be disposed in a row as shown, but their arrangement is not limited thereto.

[0046] Referring to Figure 2 Each light emitting device ED1, ED2, or ED3 can include two electrodes 20 and 40 and a light emitting layer stack 30 interposed therebetween.

[0047] The light emitting layer stack 30 can include a first electron transport layer 31, a second electron transport layer 32, a light emitting layer 34, a hole transport layer 36, and a hole injection layer 38 disposed in order.

[0048] This embodiment shows the first electron transport layer 31 and the second electron transport layer 32 disposed at the bottom and the hole transport layer 36 and the hole injection layer 38 disposed at the top, which is also referred to as an inverted structure.

[0049] Each light emitting layer stack 30 can be isolated by an insulating layer 50 and, for example, can be contained in a recess of the insulating layer 50.

[0050] Each layer of the light emitting layer stack 30 can be formed by a printing method that can include a series of processes such as printing, drying, and baking using ink.

[0051] Each layer formed in this way can be thicker near the side wall of the recess of the insulating layer 50.

[0052] The first electron transport layer 31 can include ZnO and can have reduced defects and enhanced current injection characteristics by irradiation of ultraviolet rays.

[0053] The thickness of the first electron transport layer 31 can vary depending on the light emitting device ED1, ED2, or ED3. In embodiments, for example, the first electron transport layer 31 can be thicker for the red light emitting device ED1, can be centered for the green light emitting device ED2, and can be thinner for the blue light emitting device ED3.

[0054] The second electron transport layer 32 can include ZnMgO.

[0055] The first electron transport layer 31 and the second electron transport layer 32 can be integrated into one layer, and in this case, the integrated layer can include ZnMgO.

[0056] The light emitting device ED1, ED2, or ED3 can be disposed on the intermediate insulating layer 10, and a pair of protrusions 12 can be disposed on the intermediate insulating layer 10 between the light emitting devices ED1, ED2, and ED3.

[0057] Each protrusion 12 can include an upper surface and two inclined lateral surfaces.

[0058] The lateral surfaces of the protrusion 12 can form an angle of about 20 degrees to about 60 degrees with the upper surface of the intermediate insulating layer 10, and the upper surface of the protrusion 12 can be substantially parallel to the upper surface of the intermediate insulating layer 10.

[0059] One of the two electrodes 20 and 40 can be an anode, and the other can be a cathode.

[0060] The electrode 20 can include a conductor such as a metal, a conductive metal oxide, or any combination thereof.

[0061] The electrode 20 can include a metal such as nickel, platinum, vanadium, chromium, copper, zinc, and gold, or an alloy thereof; a conductive metal oxide such as zinc oxide, indium oxide, tin oxide, indium tin oxide ("ITO"), indium zinc oxide ("IZO"), or fluorine-doped tin oxide; or a combination of a metal and an oxide such as Al and ZnO or Sb and SnO2, but embodiments of the present disclosure can not be limited thereto.

[0062] In embodiments, the electrode 20 can include a transparent conductive metal oxide such as indium tin oxide ("ITO").

[0063] The electrode 40 can include or consist of a conductor such as a metal, a conductive metal oxide, and / or a conductive polymer.

[0064] The electrode 40 can include a metal such as Al, Mg, Ca, Na, Ka, Ti, In, Y, Li, Gd, Ag, Sn, Pb, Cs, Ba, or an alloy thereof; or a multilayer material such as LiF / Al, LiO2 / Al, Liq / Al, LiF / Ca, and BaF2 / Ca, but embodiments of the present disclosure can not be limited thereto.

[0065] In embodiments, the conductive metal oxide can include those listed above.

[0066] At least one of the two electrodes 20 and 40 can be a light-transmitting electrode, and the light-transmitting electrode can include, for example, a conductive metal oxide such as zinc oxide, indium oxide, tin oxide, indium tin oxide ("ITO"), indium zinc oxide ("IZO"), or fluorine-doped tin oxide, and can include a single-layer thin film or a multi-layer thin film.

[0067] When either of the two electrodes 20 and 40 is an opaque electrode, it can include an opaque conductor such as Al, Ag, or Au.

[0068] The thickness of the two electrodes 20 and 40 in a thickness direction (e.g., a vertical direction in Figure 2 the device efficiency.

[0069] In an embodiment, for example, the thickness of the electrode can be about 5 nanometers (nm) or more (e.g., about 50 nm or more).

[0070] In an embodiment, for example, the thickness of the electrode can be about 100 micrometers (pm) or less (such as about 10 pm or less, about 1 pm or less, about 900 nm or less, about 500 nm or less, or about 100 nm or less).

[0071] The light-emitting layer 34 includes a plurality of quantum dots.

[0072] The quantum dots (hereinafter, also referred to as "semiconductor nanocrystals") can include a II-VI compound, a III-V compound, a IV-VI compound, a IV element or compound, a I-III-VI compound, a I-II-IV-VI compound, or any combination thereof.

[0073] The II-VI compound can be selected from the group including: binary compounds selected from the group consisting of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and any combination thereof; ternary compounds selected from the group consisting of CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, and any combination thereof; and quaternary compounds selected from the group consisting of HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, and any combination thereof.

[0074] The II-VI compound can further include a Group III metal.

[0075] The III-V compound can be selected from the group including: binary compounds selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and any combination thereof; ternary compounds selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, and any combination thereof; and quaternary compounds selected from the group consisting of GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and any combination thereof.

[0076] The III-V compound can further include a Group II metal (e.g., InZnP).

[0077] The Group IV-VI compound can be selected from a group comprising binary compounds selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe, and any combination thereof; ternary compounds selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and any combination thereof; and quaternary compounds selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe, and any combination thereof.

[0078] In embodiments, the Group I-III-VI compound can include, but is not limited to, CuInSe2, CuInS2, CuInGaSe, and CuInGaS.

[0079] In embodiments, the Group I-II-IV-VI compound can include, but is not limited to, CuZnSnSe and CuZnSnS.

[0080] The Group IV element or compound can be selected from a group comprising single elements selected from the group consisting of Si, Ge, and any combination thereof; and binary compounds selected from the group consisting of SiC, SiGe, and combinations thereof.

[0081] In embodiments of the present disclosure, the quantum dots can not include cadmium.

[0082] The quantum dots can include semiconductor nanocrystals based on Group III-V compounds including indium and phosphorous.

[0083] The Group III-V compound can further include zinc.

[0084] The quantum dots can include semiconductor nanocrystals based on Group II-VI compounds including a chalcogen (e.g., S, Se, Te, or combinations thereof) and zinc.

[0085] In the quantum dots, the above-described binary compounds, ternary compounds, and / or quaternary compounds can be distributed in the particles at a uniform concentration, or can be grouped into portions having different concentrations in the same particle.

[0086] The semiconductor nanocrystals can have a core / shell structure in which a first semiconductor nanocrystal (core) can be surrounded by a second semiconductor nanocrystal (shell) having the same or different composition from the first semiconductor nanocrystal.

[0087] In embodiments, the quantum dots can include a core comprising InP, InZnP, ZnSe, ZnSeTe, or any combination thereof, and a shell (or multi-shell) having a different composition from the core and comprising InP, InZnP, ZnSe, ZnS, ZnSeTe, ZnSeS, or any combination thereof.

[0088] The interface between the core and the shell can have a concentration gradient in which the concentration of elements in the shell decreases toward the center.

[0089] Additionally, the semiconductor nanocrystal can have a structure that includes a single semiconductor nanocrystal core and a multi-layer shell surrounding the core.

[0090] At this time, the multi-layer shell can include two or more layers, and each layer can have a single composition, an alloy, or a concentration gradient.

[0091] In the quantum dot, the shell material and the core material can have different energy bandgaps.

[0092] In an embodiment, for example, the energy bandgap of the shell material can be greater than the energy bandgap of the core material.

[0093] In an alternative embodiment, the energy bandgap of the shell material can be less than the energy bandgap of the core material.

[0094] The quantum dot can include a multi-layer shell.

[0095] In the multi-layer shell, the energy bandgap of an outer layer can be greater than the energy bandgap of an inner layer (i.e., a layer closer to the core).

[0096] In the multi-layer shell, the energy bandgap of an outer layer can be less than the energy bandgap of an inner layer.

[0097] The absorption / emission wavelength of the quantum dot can be adjusted by changing the composition and size of the quantum dot.

[0098] The maximum emission peak wavelength of the quantum dot can range from an ultraviolet wavelength to an infrared wavelength or more.

[0099] In an embodiment, for example, the maximum emission peak wavelength of the quantum dot can be equal to or greater than about 300 nm (such as about 500 nm or more, about 510 nm or more, about 520 nm or more, about 530 nm or more, about 540 nm or more, about 550 nm or more, about 560 nm or more, about 570 nm or more, about 580 nm or more, about 590 nm or more, about 600 nm or more, or about 610 nm or more).

[0100] The maximum emission wavelength of the quantum dot can be in a range of about 800 nm or less (such as about 650 nm or less, about 640 nm or less, about 630 nm or less, about 620 nm or less, about 610 nm or less, about 600 nm or less, about 590 nm or less, about 580 nm or less, about 570 nm or less, about 560 nm or less, about 550 nm or less, or about 540 nm or less).

[0101] The quantum dots can have a maximum emission wavelength in a range from about 500 nm to about 650 nm.

[0102] The quantum dots can have a maximum emission wavelength in a range from about 500 nm to about 540 nm.

[0103] The quantum dots can have a maximum emission wavelength in a range from about 610 nm to about 640 nm.

[0104] The quantum dots can have a quantum efficiency equal to or greater than about 10% (such as about 30% or greater, about 50% or greater, about 60% or greater, about 70% or greater, about 90% or greater, or even about 100%).

[0105] The quantum dots can have a relatively narrow optical spectrum.

[0106] The quantum dots can have a full width at half maximum of an emission wavelength spectrum equal to or less than about 50 nm (e.g., such as about 45 nm or less, about 40 nm or less, or about 30 nm or less).

[0107] The quantum dots can have a particle size (e.g., diameter or length of a longest straight line across the particle) equal to or greater than about 1 nm and equal to or less than about 100 nm.

[0108] The quantum dots can have a particle size from about 1 nm to about 50 nm (e.g., about 2 nm or greater, about 3 nm or greater, or about 4 nm or greater and about 50 nm or less, about 40 nm or less, about 30 nm or less, about 20 nm or less, or about 15 nm or less (e.g., about 10 nm or less)).

[0109] The shape of the quantum dots is not particularly limited.

[0110] In embodiments, for example, exemplary shapes of the quantum dots can include, but are not limited to, spheres, polyhedrons, pyramids, polypods, cubes, cuboids, nanotubes, nanorods, nanowires, nanoplates, or any combination thereof.

[0111] The quantum dots can be commercially available or suitably synthesized.

[0112] The particle size of the quantum dots can be relatively freely adjusted during colloidal synthesis, and the particle size can be uniform.

[0113] For example, the quantum dots can include organic ligands having hydrophobic portions.

[0114] The organic ligand portions can bind to the surface of the quantum dots.

[0115] The organic ligand can include RCOOH, RNH2, R2NH, R3N, RSH, R3PO, R3P, ROH, RCOOR, RPO(OH)2, RHPOOH, R2POOH, or combinations thereof, where each R can independently be a C3(or C5) to C24 substituted or unsubstituted aliphatic hydrocarbon group such as alkyl, alkenyl, etc., a C6 to C20 substituted or unsubstituted aromatic hydrocarbon group such as aryl, etc., or any combination thereof.

[0116] In embodiments, the organic ligand can include a thiol compound such as methanethiol, ethanethiol, propanethiol, butanethiol, pentanethiol, hexanethiol, octanethiol, dodecanethiol, hexadecanethiol, octadecanethiol, benzyl mercaptan, etc.; an amine such as methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, octylamine, nonylamine, decylamine, dodecylamine, hexadecylamine, octadecylamine, dimethylamine, diethylamine, dipropylamine, tributylamine, trioctylamine, etc.; a carboxylic acid compound such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, dodecanoic acid, hexadecanoic acid, octadecanoic acid, oleic acid, benzoic acid, etc.; a phosphine compound such as methylphosphine, ethylphosphine, propylphosphine, butylphosphine, pentylphosphine, octylphosphine, dioctylphosphine, tributylphosphine, trioctylphosphine, etc.; a phosphine oxide such as methylphosphine oxide, ethylphosphine oxide, propylphosphine oxide, butylphosphine oxide, pentylphosphine oxide, tributylphosphine oxide, octylphosphine oxide, dioctylphosphine oxide, trioctylphosphine oxide, etc.; a diphenylphosphine, triphenylphosphine compound, or an oxide thereof; a C5 to C20 alkyl phosphinic acid such as hexylphosphinic acid, octylphosphinic acid, dodecylphosphinic acid, tetradecylphosphinic acid, hexadecylphosphinic acid, and octadecylphosphinic acid; and a C5 to C20 alkyl phosphonic acid, although the disclosure is not limited thereto.

[0117] The quantum dots can individually include the hydrophobic organic ligand, or include the hydrophobic organic ligand in combination thereof.

[0118] The hydrophobic organic ligand can not include a photopolymerizable residue such as an acrylate group or a methacrylate group.

[0119] In embodiments, the light-emitting layer 34 can include a single layer of quantum dots.

[0120] In alternative embodiments, the light-emitting layer 34 can include one or more single layers (e.g., at least two, three, or four single layers and at most twenty, ten, nine, eight, seven, or six single layers) of quantum dots.

[0121] The light-emitting layer 34 can have a thickness equal to or greater than about 5 nm (such as about 10 nm or greater, about 20 nm or greater, or about 30 nm or greater) and equal to or less than about 200 nm (such as about 150 nm or less, about 100 nm or less, about 90 nm or less, about 80 nm or less, about 70 nm or less, about 60 nm or less, or about 50 nm or less).

[0122] The light-emitting layer 34 can have a thickness from about 10 nm to about 150 nm (such as from about 10 nm to about 100 nm or from about 10 nm to about 50 nm).

[0123] The light-emitting layer 34 can have a highest occupied molecular orbital ("HOMO") energy level equal to or greater than about 5.4 electron volts (eV) or greater, about 5.6 eV or greater, about 5.7 eV or greater, about 5.8 eV or greater, about 5.9 eV or greater, or about 6.0 eV or greater.

[0124] The HOMO energy level of the light-emitting layer 34 can be equal to or less than about 7.0 eV or less, about 6.8 eV or less, about 6.7 eV or less, about 6.5 eV or less, about 6.3 eV or less, or about 6.2 eV or less.

[0125] In embodiments, the light-emitting layer 34 can have a HOMO energy level from about 5.6 eV to about 6.0 eV.

[0126] The light-emitting layer 34 can have a lowest unoccupied molecular orbital ("LUMO") energy level equal to or less than about 3.8 eV (e.g., about 3.7 eV or less, about 3.6 eV or less, about 3.5 eV or less, about 3.4 eV or less, about 3.3 eV or less, about 3.2 eV or less, or about 3.0 eV or less).

[0127] The LUMO energy level of the light-emitting layer 34 can be equal to or greater than about 2.5 eV.

[0128] In embodiments, the light-emitting layer 34 can have an energy band gap from about 2.4 eV to about 2.9 eV.

[0129] A plurality of reflective members 70 can be disposed on the intermediate insulating layer 10 and between the light-emitting elements ED1, ED2, and ED3. The reflective members 70 can be spaced apart from the first electron transport layer 31 and can include an inclined surface that reflects incident light toward the first electron transport layer 31. Each reflective member 70 can be disposed between a pair of adjacent protrusions 12 and can extend to some extent along the inclined lateral surfaces of the two protrusions 12. The inclined surface of the reflective member 70 can be disposed on the inclined lateral surfaces of the protrusions 12.

[0130] The reflective member 70 can include a metal or a relatively low refractive index material, for example, an insulating material having a lower refractive index than that of the intermediate insulating layer 10.

[0131] When irradiated with ultraviolet light, the reflective member 70 can reflect the ultraviolet light, thereby exposing the thick edge portion of the first electron transport layer 31 to the ultraviolet light.

[0132] The length of the extension of the reflective member 70 can depend on the adjacent light emitting device, in particular, on the thickness of the first electron transport layer 31, which will be described with reference to Figure 3 The height of the end of the inclined surface of the reflective member 70 can be different from each other depending on the thickness of the electron transport layer 31. The edge (or end) of the inclined surface of the reflective member 70 can coincide with the upper surface of the first electron transport layer 31.

[0133] Referring to Figure 3 When the horizontal distance of the inclined lateral surface (hereinafter, referred to as an inclined surface) from the point at which the upper surface of the protrusion 12 begins to the end of the reflective member 70 is d,

[0134] d = (t1-t2) / tanθ.

[0135] Here, t1 denotes the thickness of the protrusion 12, and t2 denotes the (target) thickness of the first electron transport layer 31.

[0136] Next, the method of manufacturing a light emitting display device in an embodiment of the disclosure will be described in detail with reference to Figures 4 to 7

[0137] First, referring to Figure 4 The intermediate insulating layer 10 and the protrusion 12 thereon can be formed.

[0138] The intermediate insulating layer 10 and the protrusion 12 can be formed by a single process or from a single layer, but can also be formed by respective processes or from respective layers.

[0139] Referring to Figure 5 The electrode 20 and the reflective member 70 can be formed on the intermediate insulating layer 10 and the protrusion 12.

[0140] The electrode 20 and the reflective member 70 can be formed by a single process or from a single layer, but can also be formed by respective processes or from respective layers.

[0141] The electrode 20 and the reflective member 70 can include a metal or an organic conductive material.

[0142] Referring to Figure 6 The insulating layer 50 can be deposited and patterned such that the electrode 20 can be exposed. ​

[0143] Referring to Figure 7 The light emitting stack 30 can be formed on the exposed portion of the electrode 20 by a printing method including a printing, drying, and baking process.

[0144] Referring back to Figure 2 The electrode 40 can be formed on the light emitting stack 30 and the insulating layer 50, and the protective film 60 can be formed on the electrode 40.

[0145] Finally, the ultraviolet rays can be irradiated from one side of the middle insulating layer 10, and the irradiated ultraviolet rays can be reflected by the reflection member 70 to enter the thick edge of the first electron transport layer 31 of the light emitting stack 30.

[0146] At this time, the reflection member 70 having the appropriate extension length determined as described above can expose only the first electron transport layer 31 of the light emitting stack 30 to the ultraviolet rays, while the other portions are protected from the ultraviolet rays.

[0147] Next, the light emitting display device in another embodiment of the disclosure will be described in detail with reference to Figure 8 The light emitting display device in another embodiment of the disclosure will be described in detail with reference to

[0148] Figure 8 is a schematic cross-sectional view of an embodiment of a light emitting display device according to the disclosure.

[0149] Figure 8 The light emitting display device shown inhas a similar structure to the light emitting display device shown in Figure 2

[0150] However, the reflection member 70 can extend upward along the first inclined surface of the protrusion 12, cover the upper surface of the protrusion 12, and then extend downward to a certain degree along the second inclined surface of the protrusion 12 disposed opposite to the first inclined surface. That is, each reflection member 70 can include an inclined surface. The inclined surface of the reflection member 70 can be disposed on the second inclined surface.

[0151] At this time, the exposed portion of the second inclined surface can be reversed from the exposed portion shown in Figure 3

[0152] That is, the reflection member 70 can cover the portion corresponding to the horizontal distance d from the upper surface, and the remaining portion is exposed.

[0153] In this structure, when the ultraviolet rays are irradiated, the ultraviolet rays reflected from the first inclined surface of the reflection member 70 can be guided to the first electron transport layer 31 after passing through the exposed portion of the second inclined surface, and the ultraviolet rays traveling in other directions can be blocked by the reflection member 70. That is, the edge of the inclined surface of the reflection member 70 can coincide with the upper surface of the first electron transport layer 31. ​

[0154] Next, a light emitting display apparatus in another embodiment of the present disclosure will be described in detail with reference to Figure 9 A light emitting display apparatus in another embodiment of the present disclosure will be described in detail with reference to

[0155] Figure 9 is a schematic cross-sectional view of an embodiment of a light emitting display apparatus according to the present disclosure.

[0156] Unlike the light emitting display apparatus shown in Figure 2 the light emitting display apparatus shown in Figure 9 the light emitting display apparatus shown in does not include a separate reflection member.

[0157] Alternatively, the height of the protrusion 12 can be the same as that of the adjacent first electron transport layer 31, and the protrusion 12 can include a material having a higher refractive index than that of the intermediate insulating layer 10. The protrusion 12 can be spaced apart from the first electron transport layer 31 and can include an inclined surface that reflects incident light toward the first electron transport layer 31. The upper surface of the protrusion 12 can coincide with the upper surface of the adjacent first electron transport layer 31.

[0158] In this structure, when ultraviolet rays are irradiated, total reflection can occur on the inclined surface of the protrusion 12, so that only the first electron transport layer 31 can be exposed to the ultraviolet rays, and other layers can be affected by the ultraviolet rays none or less.

[0159] Next, a light emitting display apparatus in another embodiment of the present disclosure will be described in detail with reference to Figure 10 A light emitting display apparatus in another embodiment of the present disclosure will be described in detail with reference to

[0160] Figure 10 is a schematic cross-sectional view of an embodiment of a light emitting display apparatus according to the present disclosure.

[0161] Unlike the previous embodiment, Figure 10 the light emitting element of the light emitting display apparatus shown in

[0162] That is, the hole injection layer 110, the hole transport layer 120, the light emitting layer 130, the ZnMgO layer 140, and the ZnO layer 150 can be sequentially deposited from the bottom on the intermediate insulating layer 100.

[0163] The reflection member 170 can be disposed on the insulating layer 160, but not directly on the intermediate insulating layer 100, and can extend along the inclined surface of the groove in the insulating layer 160.

[0164] By doing so, only the ZnO layer 150 disposed on the top can be exposed to the ultraviolet rays.

[0165] Although the embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited to this and various modifications and improvements can be made by those skilled in the art using the basic concept of the present disclosure defined in the claims.

Claims

1. A light-emitting display device comprising: a first electrode; a first electron transport layer over the first electrode; a light-emitting layer over the first electron transport layer; a hole transport layer over the light-emitting layer; a hole injection layer over the hole transport layer; a second electrode over the hole injection layer; and a reflective member spaced apart from the first electron transport layer, wherein the reflective member includes an inclined surface that reflects incident light toward the first electron transport layer.

2. The light-emitting display device according to claim 1, further comprising: an intermediate insulating layer provided below the first electrode and the reflective member.

3. The light-emitting display device according to claim 2, further comprising: a protrusion over the intermediate insulating layer, wherein the protrusion includes a first slope, the inclined surface of the reflective member is provided on the first slope, and an edge of the inclined surface of the reflective member coincides with an upper surface of the first electron transport layer.

4. The light-emitting display device according to claim 2, further comprising: a protrusion over the intermediate insulating layer, wherein the protrusion includes an upper surface, a first slope, and a second slope, the second slope is provided opposite to the first slope, the reflective member covers the upper surface and the second slope, the inclined surface of the reflective member is provided on the first slope, and an edge of the inclined surface of the reflective member coincides with an upper surface of the first electron transport layer.

5. The light-emitting display device according to claim 2, wherein the reflective member has a higher refractive index than a refractive index of the intermediate insulating layer, and an upper surface of the reflective member coincides with an upper surface of the first electron transport layer. a second electron transport layer is provided between the first electron transport layer and the light-emitting layer, 6. The light-emitting display device according to any one of claims 1 to 5, further comprising: wherein the first electron transport layer includes ZnO, and the second electron transport layer includes ZnMgO.

7. A light-emitting display device comprising: a first light-emitting element; a second light-emitting element; and a reflective member provided between the first light-emitting element and the second light-emitting element, each of the first light-emitting element and the second light-emitting element including: a first electrode; a first electron transport layer over the first electrode; a light-emitting layer over the first electron transport layer; a hole transport layer over the light-emitting layer; a hole injection layer over the hole transport layer; and a second electrode over the hole injection layer, and the reflective member includes: a first inclined surface that reflects incident light toward the first electron transport layer of the first light-emitting element; and a second inclined surface that reflects incident light toward the first electron transport layer of the second light-emitting element.

8. The light-emitting display device according to claim 7, wherein the first electron transport layer of the first light-emitting element and the first electron transport layer of the second light-emitting element have different thicknesses from each other, and a height of a tip end of the first inclined surface is different from a height of a tip end of the second inclined surface.

9. The light-emitting display device according to claim 8, wherein ​ ​ the tip of the first inclined surface of the reflective member coincides with an upper surface of the first electron transport layer of the first light-emitting element, and the tip of the second inclined surface of the reflective member coincides with an upper surface of the first electron transport layer of the second light-emitting element.

10. The light-emitting display device according to claim 8, further comprising: an intermediate insulating layer provided below the first light-emitting element and the second light-emitting element and the reflective member.

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