Light-emitting element unit and display device including the same

Abstract

A light-emitting element unit and a display device including the same are provided. The light-emitting element unit has a shape extending in a first direction and includes a plurality of unit light-emitting elements spaced apart from each other and aligned in a second direction perpendicular to the first direction, and a binder formed to surround the plurality of unit light-emitting elements and fixing the plurality of unit light-emitting elements, wherein each of the plurality of unit light-emitting elements includes a first semiconductor layer, a second semiconductor layer, and an active layer disposed between the first semiconductor layer and the second semiconductor layer, and the plurality of unit light-emitting elements includes at least one first unit light-emitting element and at least one second unit light-emitting element, wherein the first unit light-emitting element has the first semiconductor layer, the active layer, and the second semiconductor layer arranged sequentially along the first direction, and the second unit light-emitting element has the second semiconductor layer, the active layer, and the first semiconductor layer arranged sequentially along the first direction.

Description

Technology Field

[0001] The present invention relates to a light-emitting element unit and a display device including the same. Background Technology

[0002] The importance of display devices is increasing along with the development of multimedia. In response to this, various types of display devices, such as Organic Light Emitting Displays (OLEDs) and Liquid Crystal Displays (LCDs), are being used.

[0003] A device for displaying images of a display device includes a display panel such as an organic light-emitting display panel or a liquid crystal display panel. Among these, as a light-emitting display panel, it may include a light-emitting element; for example, in the case of a light-emitting diode (LED), there are organic light-emitting diodes (OLEDs) that use organic materials as light-emitting materials, and inorganic light-emitting diodes that use inorganic materials as light-emitting materials. The problem to be solved

[0004] The problem to be solved by the present invention is to provide a light-emitting element unit comprising a plurality of unit light-emitting elements having different stacking directions of a plurality of semiconductor layers and a binder for fixing them, and a display device comprising the same in which a plurality of unit light-emitting elements are aligned in a direction perpendicular to each electrode.

[0005] The problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0006] A light-emitting element unit according to an embodiment for solving the above problem comprises a plurality of unit light-emitting elements having a shape extended in a first direction and spaced apart from each other in a second direction perpendicular to the first direction, and a binder formed to surround the plurality of unit light-emitting elements and fixing the plurality of unit light-emitting elements, wherein each of the plurality of unit light-emitting elements comprises a first semiconductor layer, a second semiconductor layer, and an active layer disposed between the first semiconductor layer and the second semiconductor layer, and the plurality of unit light-emitting elements comprises at least one first unit light-emitting element and at least one second unit light-emitting element, wherein the first unit light-emitting element has the first semiconductor layer, the active layer, and the second semiconductor layer arranged sequentially along the first direction, and the second unit light-emitting element has the second semiconductor layer, the active layer, and the first semiconductor layer arranged sequentially along the first direction.

[0007] The first unit light-emitting element and the second unit light-emitting element may be arranged alternately along the second direction.

[0008] The thickness of the binder in the first direction may be smaller than the length of the unit light-emitting element in the first direction.

[0009] The above unit light-emitting element includes a first end on one side of the first direction and a second end on the other side of the first direction, and the binder can expose the first end and the second end of the unit light-emitting element.

[0010] The second semiconductor layer may be located at the first end of the first unit light-emitting element, the first semiconductor layer may be located at the second end of the first unit light-emitting element, the first semiconductor layer may be located at the first end of the second unit light-emitting element, and the second semiconductor layer may be located at the second end of the second unit light-emitting element.

[0011] The binder can expose at least one end of both ends of the plurality of unit light-emitting elements.

[0012] The binder may partially wrap the outer surface of the unit light-emitting element, while completely wrapping the outer surface of the active layer.

[0013] A display device according to one embodiment for solving the above other problems comprises a substrate, a first electrode disposed on the substrate, a second electrode disposed spaced apart from the first electrode in the thickness direction of the first electrode and the substrate, and a light-emitting element unit disposed between the first electrode and the second electrode, wherein the light-emitting element unit comprises a plurality of unit light-emitting elements having a shape extended in a first direction and spaced apart from each other in a second direction perpendicular to the first direction, and a binder formed to surround the plurality of unit light-emitting elements and fixing the plurality of unit light-emitting elements, wherein each of the plurality of unit light-emitting elements comprises a first semiconductor layer, a second semiconductor layer, and an active layer disposed between the first semiconductor layer and the second semiconductor layer, and the plurality of unit light-emitting elements comprises a first unit light-emitting element in which the first semiconductor layer, the active layer, and the second semiconductor layer are sequentially disposed along the first direction, and a second unit light-emitting element in which the second semiconductor layer, the active layer, and the first semiconductor layer are sequentially disposed along the first direction.

[0014] The first direction and the thickness direction of the substrate may be parallel.

[0015] The above unit light-emitting element may include a first end electrically connected to the first electrode and a second end electrically connected to the second electrode.

[0016] The first end of the unit light-emitting element may be located at the lower end of the light-emitting element along the first direction, and the second end of the unit light-emitting element may be located at the upper end of the light-emitting element along the first direction.

[0017] The first end of the unit light-emitting element may be in contact with the first electrode, and the second end of the unit light-emitting element may be in contact with the second electrode.

[0018] The device further includes a first insulating layer that surrounds at least one region of the light-emitting element unit and is disposed on the first electrode, and the second electrode may be disposed on the first insulating layer.

[0019] The first insulating layer can expose the second end of the plurality of unit light-emitting elements.

[0020] The thickness of the binder in the first direction may be smaller than the length of the unit light-emitting element in the first direction.

[0021] The above binder can expose both ends of the unit light-emitting element.

[0022] The first unit light-emitting element and the second unit light-emitting element may be arranged alternately along the second direction.

[0023] The second electrode may overlap with the first electrode in the thickness direction of the substrate.

[0024] The light-emitting element unit includes a first light-emitting element unit and a second light-emitting element unit spaced apart from the first light-emitting element unit, wherein a plurality of unit light-emitting elements of the first light-emitting element unit overlap with the first electrode, and at least some of the plurality of light-emitting unit light-emitting elements of the second light-emitting element unit may not overlap with the first electrode.

[0025] The second light-emitting element unit may include a unit light-emitting element in which at least one of the two ends is not electrically connected to at least one of the first electrode and the second electrode.

[0026] Specific details of other embodiments are included in the detailed description and drawings. Effects of the invention

[0027] In a process of placing a plurality of unit light-emitting elements fixed by a binder on a substrate of a display device, a process of applying an electric field to orient one end of a plurality of unit light-emitting elements to have a specific direction is omitted, and a plurality of unit light-emitting elements can be placed between a first electrode and a second electrode, thereby improving the manufacturing process efficiency of the display device.

[0028] In addition, the light-emitting element unit formed by the manufacturing process according to the present embodiment may include a first unit light-emitting element and a second unit light-emitting element with opposite stacking directions in a 5:5 ratio. Accordingly, even though the electric field application process for orienting one end of a plurality of unit light-emitting elements to have a specific direction as described above is omitted, the plurality of unit light-emitting elements included in the light-emitting element unit can be arranged so that one end has a specific direction in a 5:5 ratio, so that at least 50% of the unit light-emitting elements can emit light, thereby improving the display quality of the display device.

[0029] The effects according to the embodiments are not limited to those exemplified above, and a wider variety of effects are included in this specification. Brief explanation of the drawing

[0030] FIG. 1 is a schematic perspective view of a light-emitting element unit according to one embodiment. FIG. 2 is a plan view of a light-emitting element unit according to one embodiment. Figure 3 is a cross-sectional view showing an example of cutting along line II' of Figure 2. FIGS. 4 to 11 are cross-sectional views showing the manufacturing process of the light-emitting element unit of FIG. 3. FIG. 12 is a schematic plan view of a display device according to one embodiment. FIG. 13 is a plan view showing one pixel of a display device according to one embodiment. Figure 14 is a cross-sectional view taken along the line II-II' of Figure 13. FIGS. 15 to 21 are plan views and cross-sectional views illustrating the manufacturing process of a display device according to one embodiment. FIG. 22 is an enlarged cross-sectional view showing another example of a single subpixel of the display device of FIG. 14. FIG. 23 is an enlarged cross-sectional view showing another example of a single subpixel of the display device of FIG. 14. FIG. 24 is a plan view showing one pixel of a display device according to another embodiment. FIG. 25 is a cross-sectional view taken along the line III-III' of FIG. 24. FIG. 26 is a plan view showing one pixel of a display device according to another embodiment. FIG. 27 is a cross-sectional view taken along the line IV-IV' of FIG. 26. FIG. 28 is a plan view showing one pixel of a display device according to another embodiment. FIG. 29 is a cross-sectional view showing an example of cutting along the V-V' line of FIG. 28. FIG. 30 is a cross-sectional view showing another example cut along the V-V' line of FIG. 28. FIG. 31 is a cross-sectional view showing another example cut along line II' of FIG. 2. FIG. 32 is a schematic perspective view of the unit light-emitting element of FIG. 31. FIGS. 33 to 36 are cross-sectional views showing the manufacturing process of the light-emitting element unit of FIG. 31. FIG. 37 is a plan view of a light-emitting element unit according to another embodiment. FIG. 38 is a cross-sectional view showing an example of cutting along the line VI-VI' of FIG. 37. Specific details for implementing the invention

[0031] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims.

[0032] When elements or layers are referred to as being on another element or layer, this includes cases where another layer or element is interposed directly on or in the middle of another element. Throughout the specification, the same reference numerals refer to the same components.

[0033] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another. Therefore, it goes without saying that the first component mentioned below may also be the second component within the technical scope of the present invention.

[0034] Hereinafter, embodiments will be described with reference to the attached drawings.

[0035] FIG. 1 is a schematic perspective view of a light-emitting element unit according to one embodiment.

[0036] Referring to FIG. 1, a light-emitting element unit (LS) according to one embodiment includes a plurality of unit light-emitting elements (300) and a binder (400). The plurality of unit light-emitting elements (300) have a shape that extends in one direction, and the binder (400) is formed to surround the plurality of unit light-emitting elements (300) so as to fix them.

[0037] In the drawings of the embodiments describing the light-emitting element unit (LS) below, the X direction (X), Y direction (Y), and Z direction (Z) are defined. The X direction (X) and the Y direction (Y) may be directions perpendicular to each other within a single plane. The Z direction (Z) may be a direction perpendicular to the plane where the X direction (X) and the Y direction (Y) are located. The Z direction (Z) is perpendicular to each of the X direction (X) and the Y direction (Y).

[0038] In the embodiments describing the light-emitting element unit (LS), unless otherwise noted, "top" refers to one side in the Z direction (Z), and "top surface" refers to a surface facing one side in the Z direction (Z). Additionally, "bottom" refers to the opposite direction to the other side in the Z direction (Z), and "bottom surface" refers to a surface facing the other side in the Z direction (Z). Furthermore, "left," "right," "top," and "bottom" indicate the direction when the light-emitting element unit (LS) is viewed from a plane. For example, "right" refers to one side in the X direction (X), "left" refers to the other side in the X direction (X), "top" refers to one side in the Y direction (Y), and "bottom" refers to the other side in the Y direction (Y).

[0039] The unit light-emitting element (300) is a particle-shaped element and may have a rod or cylindrical shape having a predetermined aspect ratio. The unit light-emitting element (300) may have a shape that extends in one direction. The length direction of the unit light-emitting element (300) may be parallel to the Z direction (Z). The length of the unit light-emitting element (300) is greater than the diameter of the unit light-emitting element (300), and the aspect ratio may be 6:5 to 100:1, but is not limited thereto.

[0040] The unit light-emitting element (300) may have a size ranging from a nanometer scale (1 nm or more and less than 1 µm) to a micrometer scale (1 µm or more and less than 1 mm). In one embodiment, the unit light-emitting element (300) may have both a diameter and a length of a nanometer scale or both of micrometer scales. In some other embodiments, the diameter of the unit light-emitting element (300) may have a nanometer scale, while the length of the unit light-emitting element (300) may have a micrometer scale. In some embodiments, some of the unit light-emitting elements (300) may have a diameter and / or length of a nanometer scale, while other parts of the unit light-emitting elements (300) may have a diameter and / or length of a micrometer scale.

[0041] In one embodiment, the unit light-emitting element (300) may be an inorganic light-emitting diode. The inorganic light-emitting diode may include a plurality of semiconductor layers. For example, the inorganic light-emitting diode may include a first conductivity type (e.g., n-type) semiconductor layer, a second conductivity type (e.g., p-type) semiconductor layer, and an active semiconductor layer interposed between them. The active semiconductor layer receives holes and electrons from the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, respectively, and the holes and electrons reaching the active semiconductor layer may combine with each other to emit light.

[0042] A plurality of unit light-emitting elements (300) may be spaced apart from each other in the X direction (X) and / or Y direction (Y) perpendicular to the Z direction (Z) and arranged at a predetermined interval. Although not limited thereto, a plurality of unit light-emitting elements (300) may be arranged in a matrix shape.

[0043] The binder (400) may be arranged to surround the outer surface of a plurality of unit light-emitting elements (300). The binder (400) is formed to surround at least a portion of the outer surface of the unit light-emitting elements (300). The binder (400) may be formed so that a plurality of unit light-emitting elements (300) are located within the binder (400).

[0044] The binder (400) can expose both ends of the unit light-emitting element (300). That is, the unit light-emitting element (300) can be positioned to penetrate the binder (400) in the Z direction (Z) so that both ends, namely the upper and lower ends, protrude.

[0045] FIG. 2 is a plan view of a light-emitting element unit according to one embodiment. FIG. 3 is a cross-sectional view showing one example cut along line II' of FIG. 2.

[0046] Referring to FIGS. 2 and FIGS. 3, each of the plurality of unit light-emitting elements (300) may include a first semiconductor layer, a second semiconductor layer, and an active layer disposed between the first semiconductor layer and the second semiconductor layer.

[0047] A unit light-emitting element (300) may include a first unit light-emitting element (300A) and a second unit light-emitting element (300B) that are alternately arranged in the X direction (X) and Y direction (Y) on a plane.

[0048] The first unit light-emitting element (300A) and the second unit light-emitting element (300B) may each include a first semiconductor layer, a second semiconductor layer, and an active layer disposed between the first semiconductor layer and the second semiconductor layer, and the stacking directions of the plurality of semiconductor layers and active layers described above may be opposite to each other in the first unit light-emitting element (300A) and the second unit light-emitting element (300B).

[0049] Specifically, the first unit light-emitting element (300A) may include a first semiconductor layer (310A), a second semiconductor layer (320A), and an active layer (330A) disposed between the first semiconductor layer (310A) and the second semiconductor layer (320A). The first unit light-emitting element (300A) may have the first semiconductor layer (310A), the active layer (330A), and the second semiconductor layer (320A) sequentially stacked along the length direction of the first unit light-emitting element (300A). That is, the first semiconductor layer (310A), the active layer (330A), and the second semiconductor layer (320A) of the first unit light-emitting element (300A) may be sequentially stacked along the Z direction (Z). The first semiconductor layer (310A), the active layer (330A), and the second semiconductor layer (320A) may each be the first conductivity type semiconductor layer, the active semiconductor layer, and the second conductivity type semiconductor layer described above.

[0050] The second unit light-emitting element (300B) may include a first semiconductor layer (310B), a second semiconductor layer (320B), and an active layer (330B) disposed between the first semiconductor layer (310B) and the second semiconductor layer (320B). The second unit light-emitting element (300B) may have the first semiconductor layer (310B), the active layer (330B), and the second semiconductor layer (320B) sequentially stacked along the length direction of the first unit light-emitting element (300B). That is, the second semiconductor layer (320B), the active layer (330B), and the first semiconductor layer (310B) of the first unit light-emitting element (300B) may be sequentially stacked along the Z direction (Z). The first semiconductor layer (310B), the active layer (330B), and the second semiconductor layer (320B) may each be the first conductivity type semiconductor layer, the active semiconductor layer, and the second conductivity type semiconductor layer described above.

[0051] That is, the stacking direction of a plurality of layers included in the first and second unit light-emitting elements (300A, 300B) included in the light-emitting element unit (LS) according to one embodiment may be opposite to each other. In the present specification, the meaning of "the stacking direction of a plurality of layers of the first and second unit light-emitting elements (300A, 300B) is opposite to each other" may mean that the first and second unit light-emitting elements (300A, 300B) are arranged such that the types of semiconductor layers disposed at the upper portions (ends on one side of the Z direction (Z)) of the first and second unit light-emitting elements (300A, 300B) are different from each other, and the types of semiconductor layers disposed at the lower portions (ends on the other side of the Z direction (Z)) of the first and second unit light-emitting elements (300A, 300B) are different from each other. For example, a second semiconductor layer (320A) may be located at the upper part (or end on one side in the Z direction (Z)) of the first unit light-emitting element (300A), and a first semiconductor layer (310A) may be located at the lower part (or end on the other side in the Z direction (Z)) of the first unit light-emitting element (300A); a first semiconductor layer (310B) may be located at the upper part (or end on one side in the Z direction (Z)) of the second unit light-emitting element (300B), and a second semiconductor layer (320B) may be located at the lower part (or end on the other side in the Z direction (Z)) of the second unit light-emitting element (300B).

[0052] The first semiconductor layer (310A, 310B) may be doped with a first conductivity type dopant. The first conductivity type dopant may be Si, Ge, Sn, etc. In an exemplary embodiment, the first semiconductor layer (310A, 310B) may be n-GaN doped with n-type Si.

[0053] The second semiconductor layer (320A, 320B) may be spaced apart from the first semiconductor layer (310A, 310B) with an active layer (330A, 330B) in between. The second semiconductor layer (320A, 320B) may be doped with a second conductivity type dopant such as Mg, Zn, Ca, Se, Ba, etc. In an exemplary embodiment, the second semiconductor layer (320A, 320B) may be p-GaN doped with p-type Mg.

[0054] The active layer (330A, 330B) may include a material having a single or multiple quantum well structure. As described above, the active layer (330A, 330B) may emit light by the coupling of electron-hole pairs according to an electrical signal applied through the first semiconductor layer (310A, 310B) and the second semiconductor layer (320A, 320B).

[0055] In some embodiments, the active layer (330A, 330B) may have a structure in which semiconductor materials with a large band gap energy and semiconductor materials with a small band gap energy are alternately stacked, and may include different group 3 to group 5 semiconductor materials depending on the wavelength range of the emitted light.

[0056] The light emitted from the active layer (330A, 330B) can be emitted not only on the outer surface in the longitudinal direction of the unit light-emitting element (300A, 300B), but also on both sides. That is, the light emitted from the active layer (330A, 330B) is not limited to a single direction of emission.

[0057] The binder (400) may be positioned to wrap the side of the unit light-emitting element (300), while exposing a portion of one end of the unit light-emitting element (300) and a portion of the other end opposite to the one end. The binder (400) may be positioned to completely wrap the outer surface (or side) of the active layer (330) of the unit light-emitting element (300), and may be positioned to wrap at least a portion of the outer surface (or side) of the first semiconductor layer (310A, 310B) and the second semiconductor layer (320A, 320B). The thickness (d1) of the binder (400) in the Z direction (Z) may be smaller than the length (h) of the unit light-emitting element (300) in the Z direction (Z). By forming the thickness (d1) of the binder (400) in the Z direction (Z) to be smaller than the length (h) of the unit light-emitting element (300) in the Z direction (Z), both ends of the unit light-emitting element (300) can be exposed by the binder (400).

[0058] In the light-emitting element unit (LS) according to the present embodiment, a plurality of unit light-emitting elements (300) are fixed by a binder (400), so that in the process of aligning a plurality of unit light-emitting elements (300) between a first electrode and a second electrode during the manufacturing process of the display device (10) described later, the process of applying an electric field signal to form an electric field in a specific direction between the first electrode and the second electrode and the process of forming an alignment electrode to apply an electric signal to form the electric field can be omitted. Accordingly, the manufacturing process efficiency of the display device (10) can be improved.

[0059] FIGS. 4 to 11 are cross-sectional views showing the manufacturing process of the light-emitting element unit of FIG. 3.

[0060] First, referring to FIG. 4, a lower substrate (1000) is prepared.

[0061] The lower substrate (1000) may include a base substrate (1100) and a buffer material layer (1200) disposed on the base substrate (1100).

[0062] The base substrate (1100) may include a transparent substrate such as a sapphire substrate (AlxOy) or glass. In an exemplary embodiment, the base substrate (1100) may be a sapphire substrate (AlxOy).

[0063] A plurality of semiconductor layers included in the unit light-emitting element (300) described above may be formed on one side of the base substrate (1100). The plurality of semiconductor layers included in the unit light-emitting element (300) may be formed by forming a seed crystal on the base substrate (1100) and growing it by an epitaxial method. The semiconductor layers may be formed by electron beam deposition, physical vapor deposition (PVD), chemical vapor deposition (CVD), plasma laser deposition (PLD), dual-type thermal evaporation, sputtering, metal-organic chemical vapor deposition (MOCVD), and metal-organic chemical vapor deposition (MOCVD).

[0064] Next, a buffer material layer (1200) may be formed on one side (or upper side) of the base substrate (1100). The buffer material layer (1200) may serve to reduce the difference in lattice constants between the base substrate (1100), the first semiconductor material layer (3100, see FIG. 6) and the second lower semiconductor pattern (3200B, see FIG. 5) described later. The buffer material layer (1200) may include an undoped semiconductor. The buffer material layer (1200) may include the same material as the first semiconductor material layer (3100, see FIG. 6) and / or the second lower semiconductor pattern (3200B, see FIG. 5) described later, but may include a material that is not doped with the first conductivity type dopant or the second conductivity type dopant, such as n-type or p-type. Although the drawing shows the buffer material layer (1200) stacked in a single layer, the buffer material layer (1200) may form multiple layers. In an exemplary embodiment, the buffer material layer (1200) may include a first layer comprising an undoped semiconductor and a second layer disposed on the first layer and comprising a material doped with a first conductivity type dopant.

[0065] The buffer material layer (1200) may be omitted depending on the type of base substrate (1100).

[0066] Next, referring to FIG. 5, a second lower semiconductor pattern (3200B) and a lower active layer (3300B) can be formed on the buffer material layer (1200).

[0067] Specifically, the second lower semiconductor pattern (3200B) and the lower active layer (3300B) disposed on the second lower semiconductor pattern (3200B) may be formed by patterning on the buffer material layer (1200). The second lower semiconductor pattern (3200B) and the lower active layer (3300B) may be spaced apart from each other. The second lower semiconductor pattern (3200B) and the lower active layer (3300B) correspond to the second semiconductor layer (320B) and the active layer (330B) of the second unit light-emitting element (300B) described above, respectively, and may include the same material as the material included in each layer.

[0068] The second lower semiconductor pattern (3200B) and the lower active layer (3300B) may be disposed in an area for forming a second unit light-emitting element (300B) on the buffer material layer (1200). The second lower semiconductor pattern (3200B) and the lower active layer (3300B) may form an island pattern on a planar lower substrate (1000).

[0069] The second lower semiconductor pattern (3200B) and the lower active layer (3300B) can be formed by forming the second lower semiconductor material layer and the lower active material layer on the entire surface of the buffer material layer (1200), and then etching the second lower semiconductor material layer and the lower active material layer, excluding the area for forming the second unit light-emitting element (300B). The process of forming the second lower semiconductor material layer and the lower active material layer on the entire surface of the buffer material layer (1200) can be performed by carrying out a conventional process for forming a semiconductor layer as described above. Additionally, the etching process for patterning the second lower semiconductor pattern (3200B) and the lower active layer (3300B) can be performed by forming an etching mask layer on the upper surface of the second lower semiconductor material layer and the lower active material layer disposed on the entire surface of the buffer material layer (1200), and etching in a direction perpendicular to the lower substrate (1000) along the etching mask layer.

[0070] For example, the etching process for patterning the second lower semiconductor pattern (3200B) and the lower active layer (3300B) may be a dry etching method, a wet etching method, a reactive ion etching (RIE), an inductively coupled plasma reactive ion etching (ICP-RIE), etc. In the case of a dry etching method, anisotropic etching is possible, so it may be suitable for vertical etching. When using the etching method of the above-described method, the etching etchant may be Cl2 or O2, etc. However, it is not limited thereto.

[0071] In some embodiments, the etching process for patterning the second lower semiconductor pattern (3200B) and the lower active layer (3300B) may be performed by combining dry etching and wet etching methods. For example, after first etching in the depth direction by dry etching, the etched sidewalls may be positioned in a plane perpendicular to the surface through wet etching, which is an isotropic etching method.

[0072] Next, referring to FIG. 6, a first semiconductor material layer (3100) is formed on the lower active layer (3300B).

[0073] Specifically, the first semiconductor material layer (3100) can be formed entirely on the buffer material layer (1200). The first semiconductor material layer (3100) may have a step formed on its upper surface by reflecting the step difference between the second lower semiconductor pattern (3200B) and the lower active layer (3300B) positioned below it.

[0074] The first semiconductor material layer (3100) may include a first region (3100B) that overlaps with the second lower semiconductor pattern (3200B) and the lower active layer (3300B), and a second region (3100A) that does not overlap with the second lower semiconductor pattern (3200B) and the lower active layer (3300B).

[0075] The first region (3100B) of the first semiconductor material layer (3100) can be formed by growing from the lower active layer (3300B). The first region (3100B) of the first semiconductor material layer (3100) can correspond to the first semiconductor layer (310B) of the second unit light-emitting element (300B).

[0076] The second region (3100A) of the first semiconductor material layer (3100) can be formed by growing from the buffer material layer (1200). The second region (3100A) of the first semiconductor material layer (3100) can correspond to the first semiconductor layer (310A) of the first unit light-emitting element (300A).

[0077] The process of forming a first semiconductor material layer (3100) over the lower active layer (3300B) and the buffer material layer (1200) exposed by the lower active layer (3300B) can be formed by performing a conventional process for forming a semiconductor layer as described above.

[0078] Next, referring to FIG. 7, an upper active layer (3300A) and a second upper semiconductor pattern (3200A) are formed on a second region (3100A) of the first semiconductor material layer (3100).

[0079] Specifically, the upper active layer (3300A) and the second upper semiconductor pattern (3200A) may be formed by patterning on the second region (3100A) of the first semiconductor material layer (3100). The upper active layer (3300A) and the second upper semiconductor pattern (3200A) may overlap with the second region (3100A) of the first semiconductor material layer (3100) in the Z direction (Z). The upper active layer (3300A) and the second upper semiconductor pattern (3200A) may be sequentially stacked in the groove formed by the step difference of the first semiconductor material layer (3100).

[0080] The second upper semiconductor pattern (3200A) and the upper active layer (3300A) correspond to the second semiconductor layer (320A) and the active layer (330A) of the first unit light-emitting element (300A) described above, respectively, and may include the same material as the material included in each layer.

[0081] The upper active layer (3300A) and the second upper semiconductor pattern (3200A) can be formed by forming an upper active material layer and a second upper semiconductor material layer on the first semiconductor material layer (3100) in a full area, and then etching the upper active material layer and the second upper semiconductor material layer excluding the area for forming the first unit light-emitting element (300A). The area for forming the first unit light-emitting element (300A) may be an area excluding the groove formed by the step difference of the first semiconductor material layer (3100).

[0082] The process of forming an upper active material layer and a second upper semiconductor material layer on the first semiconductor material layer (3100) can be formed by performing a conventional process for forming semiconductor layers as described above. Additionally, the etching process for patterning the second upper semiconductor pattern (3200A) and the upper active layer (3300A) can be performed by forming an etching mask layer on the upper active material layer and the second upper semiconductor material layer disposed on the first semiconductor material layer (3100) and etching along the etching mask layer in a direction perpendicular to the lower substrate (1000). The etching mask layer can be formed on the second region (3100A) of the first semiconductor material layer (3100).

[0083] For example, the etching process for patterning the upper active layer (3300A) and the second upper semiconductor pattern (3200A) may be a dry etching method, a wet etching method, a reactive ion etching (RIE), an inductively coupled plasma reactive ion etching (ICP-RIE), etc. In the case of a dry etching method, anisotropic etching is possible, so it may be suitable for vertical etching. When using the etching method of the above-described method, the etching etchant may be Cl2 or O2, etc. However, it is not limited thereto.

[0084] In some embodiments, the etching process for patterning the upper active layer (3300A) and the second upper semiconductor pattern (3200A) may be performed by combining dry etching and wet etching methods.

[0085] Next, referring to FIG. 8, a plurality of etching masks (MK) can be formed on the first semiconductor material layer and the second upper semiconductor pattern (3200A).

[0086] Specifically, a plurality of etching masks (MK) may be formed in an area for forming a first unit light-emitting element (300A) and a second unit light-emitting element (300B). For example, some of the plurality of etching masks (MK) may be formed on a first area (3100B) of a first semiconductor material layer (3100), and other parts of the plurality of etching masks (MK) may be formed on a second upper semiconductor pattern (3200A). The plurality of etching masks (MK) may be spaced apart from each other. A photoresist layer may be applied on the first semiconductor material layer (3100) and the second upper semiconductor pattern (3200A), and patterned through exposure and development to form a patterned etching mask (MK) as shown in FIG. 8.

[0087] Next, referring to FIG. 9, an etching process is performed using an etching mask (MK) to form a first unit light-emitting element (300A) and a second unit light-emitting element (300B) spaced apart from each other.

[0088] The etching process can be performed by a conventional method. For example, the semiconductor stacked structure described above can be etched by a method of etching along an etching mask (MK) in a direction perpendicular to the lower substrate (1000). Through this etching process, a plurality of semiconductor layers placed in the area where the etching mask (MK) is placed are not etched, and a plurality of semiconductor layers placed in the area where the etching mask (MK) is not placed are etched, so that a first unit light-emitting element (300A) and a second unit light-emitting element (300B) spaced apart from each other can be formed as shown in FIG. 9.

[0089] The etching process may be a dry etching method, a wet etching method, a reactive ion etching (RIE), an inductively coupled plasma reactive ion etching (ICP-RIE), etc. In the case of a dry etching method, anisotropic etching is possible, so it may be suitable for vertical etching. When using the etching method described above, the etching etchant may be Cl2 or O2, etc. However, it is not limited thereto.

[0090] In some embodiments, the etching process may be performed by combining dry etching and wet etching methods. For example, depth etching may be performed first by dry etching, and then the etched sidewall may be placed in a plane perpendicular to the surface through wet etching, which is an isotropic etching method.

[0091] Next, referring to FIG. 10, a binder material layer (4000) is formed to surround the outer surface of a plurality of unit light-emitting elements (300).

[0092] A binder material layer (4000) may be formed to surround a plurality of unit light-emitting elements (300). The binder material layer (4000) may be formed to expose the upper portions of the plurality of unit light-emitting elements (300). Specifically, the thickness (d2) of the binder material layer (4000) in the Z direction may be smaller than the length (h) in the extension direction of the unit light-emitting element (300). Accordingly, a second semiconductor layer (320A) located at the upper portion of the first unit light-emitting element (300A) and a first semiconductor layer (310B) located at the upper portion of the second unit light-emitting element (300B) may be exposed by the binder material layer (4000).

[0093] The upper surface of the binder material layer (4000) is formed substantially flat so as to form a surface parallel to the lower substrate (1000). The lower surface of the binder material layer (4000) can be formed to contact the upper surface of the buffer material layer (1200) of the lower substrate (1000).

[0094] The binder material layer (4000) can be formed to completely fill the space between a plurality of unit light-emitting elements (300) formed on the lower substrate (1000). The binder material layer (4000) can serve to fix them by being formed to completely fill the space between the plurality of unit light-emitting elements (300).

[0095] Meanwhile, the binder material layer (4000) may be formed by applying or spraying a material constituting the binder material layer (4000) onto a unit light-emitting element (300). In one embodiment, the binder material layer (4000) may be formed on a lower substrate (1000) through an inkjet printing method, a spin coating method, a die-slot coating method, a slit coating method, etc. However, it is not limited thereto.

[0096] The binder material layer (4000) may be formed by including an insulating material. The insulating material may include a non-insulating material or an inorganic insulating material. Examples of inorganic insulating materials include inorganic materials including polymers or nitride-based inorganic materials. Inorganic insulating materials such as silicon nitride (SiNx) and aluminum nitride (AlN) may be included. Additionally, the polymer may use photosensitive polymers such as PMMA (poly(methylmethacrylate)) and PMGI (poly(methyl glutarimide)), but is not limited thereto. Examples of organic insulating materials may include polyimide (PI), but are not limited thereto.

[0097] Next, referring to FIG. 11, a light-emitting element structure (LS') comprising a plurality of unit light-emitting elements (300) and a binder material layer (4000) is separated from a lower substrate (1000).

[0098] The process of separating the light-emitting element structure (LS') from the lower substrate (1000) is not particularly limited. Although not shown in the drawings, the process of separating the light-emitting element structure (LS') from the lower substrate (1000) may be performed by a physical separation method or a chemical separation method, etc. By the above separation process, the lower surface of the light-emitting element structure (LS') may include the lower surface of the binder material layer (4000), the lower surface of the first unit light-emitting element (300A), and the lower surface of the second unit light-emitting element (300B). That is, the lower surface of the binder material layer (4000) may be parallel to the lower surfaces of the first unit light-emitting element (300A) and the second unit light-emitting element (300B).

[0099] Next, the binder material layer (4000) may be reduced in thickness due to hardening or degradation, thereby forming the binder (400) of FIG. 3. Accordingly, the thickness of the binder material layer (4000) is reduced in the Z direction (Z), so that the lower portions of the first unit light-emitting element (300A) and the second unit light-emitting element (300B) may be exposed by the binder (400) as shown in FIG. 3.

[0100] In the manufacturing process of the light-emitting element unit (LS) according to the present embodiment, a binder (400) containing an insulating material is used in the process of separating a plurality of unit light-emitting elements (300) from a lower substrate (1000) so that the plurality of unit light-emitting elements (300) can be separated as a single unit without separating the plurality of unit light-emitting elements (300) individually. Accordingly, damage to the semiconductor layer disposed on the lower part of each unit light-emitting element (300) can be prevented.

[0101] In addition, the light-emitting element unit (LS) formed by the manufacturing process according to the present embodiment can be configured such that, in the process of placing a plurality of unit light-emitting elements (300) fixed by a binder (400) on a substrate (SUB) of a display device (10), the process of applying an electric field to orient one end of a plurality of unit light-emitting elements (300) to have a specific direction is omitted, and a plurality of unit light-emitting elements can be placed between a first electrode and a second electrode, thereby improving the manufacturing process efficiency of the display device (10) described later.

[0102] In addition, the light-emitting element unit (LS) formed by the manufacturing process according to the present embodiment may include a first unit light-emitting element (300A) and a second unit light-emitting element (300B) having opposite stacking directions in a 5:5 ratio. Accordingly, even though the electric field application process for orienting one end of a plurality of unit light-emitting elements (300) to have a specific direction as described above is omitted, the plurality of unit light-emitting elements (300) included in the light-emitting element unit (LS) can be arranged so that one end has a specific direction in a 5:5 ratio, so that at least 50% of the unit light-emitting elements (300) can emit light, and thus the display quality of the display device (10) described later can be improved.

[0103] FIG. 12 is a schematic plan view of a display device according to one embodiment.

[0104] Referring to FIG. 12, the display device (10) displays a video or a still image. The display device (10) may refer to any electronic device that provides a display screen. For example, a television, laptop, monitor, billboard, Internet of Things, mobile phone, smartphone, tablet PC (Personal Computer), electronic watch, smart watch, watch phone, head-mounted display, mobile communication terminal, electronic notebook, e-book, PMP (Portable Multimedia Player), navigation, game console, digital camera, camcorder, etc. that provide a display screen may be included in the display device (10).

[0105] The display device (10) includes a display panel that provides a display screen. Examples of display panels include an inorganic light-emitting diode display panel, an organic light-emitting diode display panel, a quantum dot light-emitting diode display panel, a plasma display panel, a field emission display panel, etc. In the following examples, an inorganic light-emitting diode display panel is used as an example of a display panel, but it is not limited thereto, and if the same technical concept is applicable, it can be applied to other display panels.

[0106] In the drawings of the embodiments describing the display device (10), a first direction (DR1), a second direction (DR2), and a third direction (DR3) are defined. The first direction (DR1) and the second direction (DR2) may be directions perpendicular to each other within a single plane. The third direction (DR3) may be a direction perpendicular to the plane where the first direction (DR1) and the second direction (DR2) are located. The third direction (DR3) is perpendicular to each of the first direction (DR1) and the second direction (DR2). In the embodiments describing the display device (10), the third direction (DR3) represents the thickness direction (or display direction) of the display device (10).

[0107] The display device (10) may have a rectangular shape that includes a long side and a short side where the first direction (DR1) in the plane is longer than the second direction (DR2). The corners where the long and short sides of the display device (10) in the plane may be right angles, but are not limited thereto, and may have a rounded curved shape. The shape of the display device (10) is not limited to the examples provided and may be varied in many ways. For example, the display device (10) may have other shapes such as a square in the plane, a square with rounded corners (vertices), other polygons, circles, etc.

[0108] The display surface of the display device (10) may be positioned on one side of the third direction (DR3), which is the thickness direction. Unless otherwise noted in the embodiments describing the display device (10), "top" indicates the display direction toward one side of the third direction (DR3), and "top surface" indicates the surface facing toward one side of the third direction (DR3). Additionally, "bottom" indicates the direction opposite to the display direction toward the other side of the third direction (DR3), and "bottom surface" refers to the surface facing toward the other side of the third direction (DR3). Furthermore, "left," "right," "top," and "bottom" indicate the direction when the display device (10) is viewed from a plane. For example, "right" indicates one side of the first direction (DR1), "left" indicates the other side of the first direction (DR1), "top" indicates one side of the second direction (DR2), and "bottom" indicates the other side of the second direction (DR2).

[0109] The display device (10) may include a display area (DPA) and a non-display area (NDA). The display area (DPA) is an area where the screen can be displayed, and the non-display area (NDA) is an area where the screen is not displayed.

[0110] The shape of the display area (DPA) can follow the shape of the display device (10). For example, the shape of the display area (DPA) may have a planar rectangular shape similar to the overall shape of the display device (10). The display area (DPA) may generally occupy the center of the display device (10).

[0111] The display area (DPA) may include a plurality of pixels (PX). The plurality of pixels (PX) may be arranged in a matrix direction. The shape of each pixel (PX) may be a planar rectangle or a square. In an exemplary embodiment, each pixel (PX) may include a plurality of light-emitting elements made of inorganic particles.

[0112] A non-display area (NDA) may be placed around a display area (DPA). The non-display area (NDA) may surround the display area (DPA) in whole or in part. The non-display area (NDA) may form the bezel of the display device (10).

[0113] FIG. 13 is a plan view showing one pixel of a display device according to one embodiment. FIG. 14 is a cross-sectional view taken along the line II-II' of FIG. 13.

[0114] Referring to FIGS. 13 and 14, each pixel (PX) of a display device (10) for displaying full color may include a plurality of subpixels (SPX: SPX1, SPX2, SPX3). Each pixel (PX) may include a first subpixel (SPX1) that emits light of a first color, a second subpixel (SPX2) that emits light of a second color, and a third subpixel (SPX3) that emits light of a third color. The first subpixel (SPX1), the second subpixel (SPX2), and the third subpixel (SPX3) may be provided one by one for each pixel (PX). Each subpixel (SPX) may be sequentially arranged in a repeating manner along a first direction (DR1) as the first subpixel (SPX1), the second subpixel (SPX2), and the third subpixel (SPX3). For example, the first color may be red, the second color may be green, and the third color may be blue.

[0115] Each subpixel (SPX) of the display device (10) may include a light-emitting region (EMA: EMA1, EMA2, EMA3) and a non-light-emitting region (NEM). The light-emitting region (EMA) is an area where a light-emitting element unit (LS) is placed and light is emitted, and the non-light-emitting region (NEM) can be defined as an area where light is not emitted.

[0116] The light-emitting region (EMA) may include a first light-emitting region (EMA1), a second light-emitting region (EMA2), and a third light-emitting region (EMA3). The first to third light-emitting regions (EMA1, EMA2, EMA3) may each be a light-emitting region (EMA) of the first to third subpixels (SPX1, SPX2, SPX3). For example, the first light-emitting region (EMA1) may be a light-emitting region (EMA) of the first subpixel (SPX1), the second light-emitting region (EMA2) may be a light-emitting region (EMA) of the second subpixel (SPX2), and the third light-emitting region (EMA3) may be a light-emitting region (EMA) of the third subpixel (SPX3).

[0117] A non-emissive region (NEM) may be arranged to surround a plurality of emitting regions (EMA: EMA1, EMA2, EMA3). A non-emissive region (NEM) of one subpixel (SPX) abuts a non-emissive region (NEM) of an adjacent subpixel (SPX) (regardless of whether it is a subpixel (SPX) within the same pixel (PX). The non-emissive regions (NEM) of adjacent subpixels (SPX) may be connected as one, and furthermore, the non-emissive regions (NEM) of all subpixels (SPX) may be connected as one, but are not limited thereto. The emitting regions (EMA) of each adjacent subpixel (SPX) may be separated by a non-emissive region (NEM).

[0118] A display device (10) according to one embodiment includes a substrate (SUB), a circuit layer (CCL), and a light-emitting element layer (EML).

[0119] The substrate (SUB) may be an insulating substrate. The substrate (SUB) may be made of an insulating material such as glass, quartz, or polymer resin. The substrate (SUB) may be a rigid substrate, but it may also be a flexible substrate capable of bending, folding, rolling, etc.

[0120] The circuit layer (CCL) may be disposed on one side of the substrate (SUB). The circuit layer (CCL) may include at least one transistor, etc., to drive the light-emitting element layer (EML) of each pixel (PX) (or sub-pixel (SPX)).

[0121] A light-emitting element layer (EML) may be disposed on one side of the circuit layer (CCL). The light-emitting element layer (EML) may include a first electrode (210), a second electrode (220), a light-emitting element unit (LS), a first insulating layer (510), and a second insulating layer (520).

[0122] The first electrode (210) can be placed on the circuit layer (CCL). The first electrode (210) can be placed corresponding to each subpixel (SPX). The first electrode (210) can be patterned and placed in the light-emitting region (EMA) of each subpixel (SPX). The first electrode (210) placed in each subpixel (SPX) can be spaced apart from each other in a first direction (DR1) and a second direction (DR2). Accordingly, the first electrode (210) can be arranged in an island-shaped pattern on the front surface of the planar display device (10).

[0123] The first electrode (210) may have a rectangular shape in a planar view, including one side extended in the first direction (DR1) and the other side extended in the second direction (DR2). However, it is not limited thereto, and the first electrode (210) may have a shape tilted relative to the first direction (DR1) or a circular shape with a curved outer surface. Additionally, the size of the first electrode (210) is not particularly limited, but may vary depending on the area of ​​each sub-pixel (SPX) of the display device (10). As shown in the drawing, the first electrode (210) may be placed within the sub-pixel (SPX) but formed to be smaller than the sub-pixel (SPX), thereby being placed in a state spaced apart from the boundary of an adjacent sub-pixel (SPX).

[0124] The first electrode (210) can be electrically connected to a driving transistor of the circuit layer (CCL) described later. The first electrode (210) can be electrically connected to different driving transistors (DTR) placed for each subpixel (SPX), and can receive a first power supply voltage independently from each of them.

[0125] The second electrode (220) is positioned above the first electrode (210) and may be positioned corresponding to each subpixel (SPX). In an exemplary embodiment, the second electrode (220) may be patterned and positioned at each subpixel (SPX). The second electrode (220) positioned at each subpixel (SPX) may be positioned spaced apart from adjacent subpixels (SPX) in the first direction (DR1) or the second direction (DR2). Accordingly, the second electrode (210) may be positioned in an island-shaped pattern on the front surface of the display device (10). However, it is not limited thereto, and the second electrode (220) positioned at one pixel (PX) may be positioned at two or more subpixels (SPX), and the second electrode (220) positioned at the first to third subpixels (SPX1, SPX2, SPX3) may be extended from one another. An explanation regarding this will be provided later with reference to other drawings.

[0126] The second electrode (220) may have a planar angular shape including one side extended in the first direction (DR1) and the other side extended in the second direction (DR2). However, it is not limited thereto, and the second electrode (220) may have a shape tilted relative to the first direction (DR1) or a circular shape with a curved outer surface. As shown in the drawing, the second electrode (220) is placed within a subpixel (SPX) but is formed to be smaller than the subpixel (SPX), so that it can be placed in a spaced-away state from the boundary with an adjacent subpixel (SPX). Accordingly, each patterned second electrode (220) is placed in each subpixel (SPX), and the unit light-emitting elements (300) placed in a plurality of subpixels (SPX) included in one pixel (PX) can be electrically connected to each second electrode (220) that is spaced apart from each other.

[0127] At least a portion of the second electrode (220) may be arranged to overlap the first electrode (210) and the third direction (DR3). The second electrode (220) and the first electrode (210) may have different widths or areas. In an exemplary embodiment, the second electrode (220) may be formed to have a larger area than the first electrode (210). That is, the width measured in one direction of the second electrode (220), for example, the first direction (DR1) or the second direction (DR2), may be larger than the width measured in the first direction (DR1) or the second direction (DR2) of the first electrode (210).

[0128] A light-emitting element unit (LS) may be positioned corresponding to each subpixel (SPX). The light-emitting element unit (LS) positioned in each subpixel (SPX) may be positioned in the light-emitting region (EMA) of each subpixel (SPX). Meanwhile, although the drawings show the light-emitting element unit (LS) positioned within the light-emitting region (EMA), it is not limited thereto. In some other embodiments, the light-emitting element unit (LS) may be positioned such that a portion of the light-emitting element unit (LS) is located in the non-light-emitting region (NEM). A detailed description thereof will be provided later with reference to other drawings.

[0129] The drawing illustrates two light-emitting element units (LS) arranged in a single column in one subpixel (SPX), but is not limited thereto. For example, one light-emitting element unit (LS) may be placed in one subpixel (SPX), or three or more light-emitting element units (LS) may be placed. Additionally, the two light-emitting element units (LS) placed in one subpixel (SPX) may be arranged in a single column but may be arranged randomly in an alternating manner rather than parallel to each other, and multiple light-emitting element units (LS) may be arranged in multiple columns.

[0130] A light-emitting element unit (LS) may be disposed between the first electrode (210) and the second electrode (220). The light-emitting element unit (LS) may be disposed on the first electrode (210) such that at least a portion of the area overlaps the first electrode (210) and the third direction (DR3). In one embodiment, the light-emitting element unit (LS) may be disposed to overlap the first electrode (210) and the third direction (DR3). The light-emitting element unit (LS) may be disposed between the first electrode (210) and the second electrode (220) described later.

[0131] As described above, the light-emitting element unit (LS) includes a plurality of unit light-emitting elements (300) and a binder (400). The unit light-emitting element (300) penetrates the binder (400) in a third direction (DR3), and the binder (400) can fix the plurality of unit light-emitting elements (300).

[0132] Each unit light-emitting element (300) may have a shape that extends in a third direction (DR3). A plurality of unit light-emitting elements (300) may be spaced apart from each other in a first direction (DR1) and / or a second direction (DR2) perpendicular to the third direction (DR3). As the binder (400) fixes the unit light-emitting elements (300) that extend in the third direction (DR3), the plurality of unit light-emitting elements (300) may be arranged parallel to each other.

[0133] Both ends of a plurality of unit light-emitting elements (300) may be exposed by the binder (400). The plurality of unit light-emitting elements (300) whose ends are exposed by the binder (400) may include a first end electrically connected to a first electrode (210) and a second end electrically connected to a second electrode (220). In this embodiment, the first end of the plurality of unit light-emitting elements (300) may be a lower end, and the second end of the plurality of unit light-emitting elements (300) may be an upper end. The first end of the plurality of unit light-emitting elements (300) may be in direct contact with the first electrode (210), and the second end of the plurality of unit light-emitting elements (300) may be in direct contact with the second electrode (220).

[0134] A first semiconductor layer (310A) may be located at the first end of the first unit light-emitting element (300A), and a second semiconductor layer (320B) may be located at the first end of the second unit light-emitting element (300B). Additionally, a second semiconductor layer (320A) may be located at the second end of the first unit light-emitting element (300A), and a first semiconductor layer (310B) may be located at the second end of the second unit light-emitting element (300B). Accordingly, the first semiconductor layer (310A) of the first unit light-emitting element (300A) and the second semiconductor layer (320B) of the second unit light-emitting element (300B) can be electrically connected to the first electrode (210), and the second semiconductor layer (320A) of the first unit light-emitting element (300A) and the first semiconductor layer (310B) of the second unit light-emitting element (300B) can be electrically connected to the second electrode (220).

[0135] A first insulating layer (510) may be disposed on a circuit layer (CCL) and a first electrode (210) where a plurality of light-emitting element units (LS) are not disposed. The first insulating layer (510) may fill the area where light-emitting element units (LS) are not disposed in the region between the first electrode (210) and the second electrode (220).

[0136] The first insulating layer (510) may be arranged to surround the outer surface of the unit light-emitting element (300) exposed by the binder (400) and the binder (400) disposed on the first electrode (210). The outer surface of the unit light-emitting element (300) and the outer surface of the binder (400) may come into direct contact with the first insulating layer (510).

[0137] The first insulating layer (510) may be formed lower than the height from the circuit layer (CCL) to one end of the unit light-emitting element (300) so that at least one end of the unit light-emitting element (300) is exposed. Accordingly, the upper end (or second end) of the unit light-emitting element (300) may protrude above the upper surface of the first insulating layer (510), so that the outer surface does not come into direct contact with the first insulating layer (510). The outer surface of the protruding portion of the light-emitting element (300) may come into contact with the second electrode (220) disposed on the first insulating layer (510). That is, according to one embodiment, the thickness of the first insulating layer (510) may be smaller than the sum of the thickness of the first electrode (210) and the height of the unit light-emitting element (300). The first insulating layer (510) may include an inorganic insulating material or an organic insulating material.

[0138] The second electrode (220) is disposed on the first insulating layer (510) and can come into contact with at least the upper portion of the unit light-emitting element (300) protruding above the upper surface of the first insulating layer (510). For example, the second electrode (220) can be disposed to surround the upper portion of the unit light-emitting element (300). The first electrode (210) can come into contact with the lower portion of the unit light-emitting element (300), and the second electrode (220) can come into contact with the upper portion of the unit light-emitting element (300). Thus, the upper portions of the unit light-emitting elements (300) can be electrically connected to the second electrode (220).

[0139] Although not illustrated, the second electrode (220) may be electrically connected to the second power wiring. The second electrode (220) may receive the second power voltage applied through the second power wiring. The second electrode (220) may be electrically connected to the same second power wiring placed across a plurality of subpixels (SPX) and may receive the same second power voltage from each of them. Additionally, in some embodiments, when a single second electrode (220) is placed across a plurality of subpixels (SPX), the plurality of subpixels (SPX) may receive the same electrical signal applied to the second power wiring through a single integrated second electrode (220).

[0140] In an exemplary embodiment, the first electrode (210) is a pixel electrode separated for each subpixel (PXn), and the second electrode (220) may be a common electrode connected in common along each subpixel (SPX).

[0141] Each electrode (210, 220) may include a transparent conductive material. For example, each electrode (210, 220) may include a material such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), ITZO (Indium Tin-Zinc Oxide), etc., but is not limited thereto. The unit light-emitting element (300) may emit light in both end directions and may emit light in a third direction (DR3) toward which the upper surface of the first electrode (210) in the drawing faces. In some embodiments, the first electrode (210) may include a highly reflective conductive material to reflect light emitted from the unit light-emitting element (300) and traveling toward the upper surface of the first electrode (210). A portion of the light emitted from the unit light-emitting element (300) may pass through a second electrode (220) containing a transparent material and be emitted from each subpixel (PXn), and another portion may be reflected from a first electrode (210) containing a highly reflective material and be emitted from each subpixel (PXn). In an exemplary embodiment, the first electrode (210) may include a metal such as silver (Ag), copper (Cu), aluminum (Al), etc., as a highly reflective material.

[0142] A plurality of unit light-emitting elements (300) may be spaced apart from each other on the first electrode (210). The spacing between unit light-emitting elements (300) arranged extending along one direction in the same row or column may generally be the same. Additionally, a plurality of unit light-emitting elements (300) may be spaced apart from each other and substantially arranged parallel to each other. This may be a structure formed by patterning a plurality of unit light-emitting elements (300) at regular intervals through an etching process during the manufacturing process of the element unit (LS), and fixing a plurality of unit light-emitting elements (300) inside the binder (400) using a material included in the binder (400).

[0143] The second insulating layer (520) may be placed on the second electrode (220). The second insulating layer (520) may be placed on the substrate (SUB) and may serve to protect a plurality of members placed below it.

[0144] FIGS. 15 to 21 are plan views and cross-sectional views illustrating the manufacturing process of a display device according to one embodiment.

[0145] First, referring to FIGS. 15 and 16, a substrate (SUB) and a circuit layer (CCL) formed on the substrate (SUB) are prepared. Next, a first electrode (210) is formed on the circuit layer (CCL). The first electrode (210) can be placed within each light-emitting region (EMA) of each subpixel (SPX).

[0146] Next, referring to FIGS. 17 and 18, a plurality of light-emitting element units (LS) are placed on the first electrode (210). The process of placing the light-emitting element units (LS) can be performed by spraying ink in which the plurality of light-emitting element units (LS) are dispersed onto the first electrode (210). The process of placing the plurality of light-emitting element units (LS) on the first electrode (210) can be performed using only an inkjet process without forming a separate electric field.

[0147] Next, referring to FIGS. 19 and 20, a first insulating layer (510) is formed on a substrate (SUB) on which a plurality of light-emitting element units (LS) are arranged. The first insulating layer (510) can fill the spaced-out area where the light-emitting element units (LS) are not arranged. The first insulating layer (510) can be formed so that the upper portions of the plurality of unit light-emitting elements (300) of the light-emitting element units (LS) are exposed.

[0148] Next, referring to FIG. 21, a second electrode (220) is formed on the first insulating layer (510). The second electrode (220) may be formed in a patterned manner so as to be spaced apart from each subpixel (SPX). Then, a second insulating layer (520) is formed on the second electrode (220) to manufacture the display device (10) shown in FIG. 14.

[0149] FIG. 22 is an enlarged cross-sectional view showing another example of a single subpixel of the display device of FIG. 14.

[0150] Referring to FIG. 22, the display device according to the present embodiment differs from the embodiment of FIG. 14 in that the first electrode (210_1) is formed in a plurality of layers.

[0151] Specifically, in one embodiment, the display device (10) may have a first electrode (210_1) that includes a plurality of layers. The first electrode (210_1) may include a layer containing a transparent material and a layer containing a material with high reflectivity. Accordingly, at least a portion of the light emitted from the second unit light-emitting element (300B) and incident toward the first electrode (210_1) may be reflected toward the upper direction of the substrate (SUB) from the upper surface of the layer containing the material with high reflectivity among the plurality of layers forming the first electrode (210_1).

[0152] The first electrode (210_1) may include a first electrode base layer (211) and a first electrode upper layer (212) disposed on the first electrode base layer (211) in a stacked structure.

[0153] The first electrode base layer (211) is disposed on the circuit layer (CCL), and the first electrode upper layer (212) can be disposed to cover the upper surface of the first electrode base layer (211). The first electrode base layer (211) and the first electrode upper layer (212) can be patterned by a single mask process. In an exemplary embodiment, the side walls of the first electrode base layer (211) and the first electrode upper layer (212) can be aligned side by side.

[0154] The first electrode base layer (211) and the first electrode upper layer (212) may both comprise a conductive material to form a single first electrode (210_1). The first electrode base layer (211) may comprise a conductive material with high reflectivity, and the first electrode upper layer (212) may comprise a transparent conductive material. Among the light emitted from the unit light-emitting element (300) (specifically, the second unit light-emitting element (300B)), the light traveling toward the first electrode (210_1) may pass through the first electrode upper layer (212) containing a transparent material and travel toward the upper surface of the first electrode base layer (211). At least some of the light incident toward the first electrode base layer (211) may be reflected from the upper surface of the first electrode base layer (211) toward the upper direction of the substrate (SUB). However, not limited thereto, the first electrode upper layer (212) may include a conductive material with high reflectivity, and among the light emitted from the unit light-emitting element (300) (specifically, the second unit light-emitting element (300B)), the light traveling toward the first electrode (210_1) may be reflected from the upper surface of the first electrode upper layer (212) toward the upper direction of the substrate (SUB).

[0155] In this embodiment, light emitted through the first end positioned on the side of the first electrode (210_1) among the two ends of the second unit light-emitting element (300B) among the plurality of unit light-emitting elements (300) can proceed toward the first electrode (210_1), and light emitted through the second end positioned on the side of the second electrode (220) among the two ends of the second unit light-emitting element (300B) can pass through the second electrode (220) as described above and be emitted to the outside of the display device (10). Accordingly, by forming the electrode base layer (211) to include a reflective material, at least a portion of the light emitted from the second unit light-emitting element (300B) and proceeding toward the first electrode (210_1) can be reflected from the upper surface of the electrode base layer (211) and propagated toward the upper direction of the substrate (SUB), thereby improving the light efficiency of the display device (10).

[0156] FIG. 23 is an enlarged cross-sectional view showing another example of a single subpixel of the display device of FIG. 14.

[0157] Referring to FIG. 23, the display device according to the present embodiment differs from the embodiment of FIG. 14 in that the first insulating layer (510) further includes a scattering body (511).

[0158] Specifically, the scattering body (511) may be included in the first insulating layer (510) in a dispersed state. The scattering body (511) may have a refractive index different from that of the first insulating layer (510) and may form an optical interface with the first insulating layer (510). For example, the scattering body (511) may be a light scattering particle. The scattering body (511) is not particularly limited as long as it is a material capable of scattering at least a portion of the transmitted light, but may be, for example, a metal oxide particle or an organic particle. Examples of the metal oxide may include titanium oxide (TiOx), zirconium oxide (ZrOx), aluminum oxide (AlxOy), indium oxide (InxOy), zinc oxide (ZnO), or tin oxide (SnOx), and examples of the organic particle material may include an acrylic resin or a urethane resin. The scatterer (511) can scatter light in random directions regardless of the incident direction of the incident light without substantially changing the wavelength of the light passing through the first insulating layer (510).

[0159] In this embodiment, some of the light emitted from the second unit light-emitting element (300B) may be incident on a scatterer (511) included in the first insulating layer (510) and scattered by the scatterer (511). The scatterer (511) can scatter the light emitted from a plurality of unit light-emitting elements (300) arranged in parallel in one direction (e.g., the third direction (DR3)) so that the light does not travel only in a specific direction, and accordingly, the display device (10) can emit light of uniform density by including the scatterer (511).

[0160] FIG. 24 is a plan view showing one pixel of a display device according to another embodiment. FIG. 25 is a cross-sectional view taken along the line III-III' of FIG. 24.

[0161] Referring to FIGS. 24 and 25, the display device (10) according to the present embodiment differs from the embodiment of FIGS. 13 and 14 in that the second electrode (220_1) is arranged to cover the light-emitting region (EMA) of a plurality of subpixels (SPX) included in one pixel (PX).

[0162] Specifically, the second electrode (220_1) may be a common electrode for each pixel (PX). The second electrode (220_1) may not be spaced apart from each subpixel (SPX) in the pixel (PX), but may be extended to a plurality of adjacent subpixels (SPX) in the first direction (DR1) from the pixel (PX). That is, the second electrode (220_1) may be arranged to cover all of the plurality of light-emitting regions (EMA) included in each subpixel (SPX). Accordingly, the second electrode (220_1) of each subpixel (SPX) included in the pixel (PX) may be formed integrally without being spaced apart from each other in the non-light-emitting region (NEM).

[0163] The area of ​​the second electrode (220_1) may be formed to be larger than the sum of the areas of the first to third light-emitting regions (EMA1, EMA2, EMA3). However, it is not limited thereto, and the second electrode (220_1) may be formed to extend to and become integrated with a plurality of adjacent pixels (PX).

[0164] Although not shown in the drawing, the second electrode (220_1) placed in each pixel (PX) is electrically connected to the second power wiring and the same electrical signal can be applied. In this embodiment, the second electrode (220_1) is placed in a plurality of sub-pixels (SPX) in an integrated shape, so that the same electrical signal can be applied through the second electrode (220_1) which is electrically connected to the second power wiring.

[0165] Additionally, as the second electrode (220_1) is positioned to cover a plurality of subpixels (SPX), the second power wiring may be positioned only in some pixels (PX) or subpixels (SPX) and not in some subpixels (SPX). Although not shown in the drawing, a portion of the second power wiring and the second electrode (220_1) may be electrically connected in one of the first to third subpixels (SPX1, SPX2, SPX3) included in a pixel (PX).

[0166] FIG. 26 is a plan view showing one pixel of a display device according to another embodiment. FIG. 27 is a cross-sectional view taken along the line IV-IV' of FIG. 26.

[0167] Referring to FIGS. 26 and 27, a plurality of light-emitting element units (LS) may include a first light-emitting element unit (LS1), a second light-emitting element unit (LS2), and a third light-emitting element unit (LS3).

[0168] The first light-emitting element unit (LS1) may be a light-emitting element unit (LS) in which a plurality of unit light-emitting elements (300) included in the first light-emitting element unit (LS1) overlap with a first electrode (210) disposed in each subpixel (SPX) in a third direction (DR3). The first light-emitting element unit (LS1) may be disposed within the light-emitting region (EMA) of each subpixel (SPX) and overlap with the first electrode (210) and the second electrode (220) in a third direction (DR3).

[0169] The second light-emitting element unit (LS2) may be a light-emitting element unit in which at least some of the plurality of unit light-emitting elements (300) included in the second light-emitting element unit (LS2) are placed in a non-light-emitting region (NEM), and other parts are placed on the first electrode (210) of another subpixel (SPX) that is spaced apart from each other. For example, as shown in FIG. 26, some of the unit light-emitting elements (300) included in the second light-emitting element unit (LS2) are placed in a non-light-emitting region (NEM) located between the first light-emitting region (EMA1) and the second light-emitting region (EMA2), and other parts of the unit light-emitting elements (300) are placed in the first light-emitting region (EMA1) so as to overlap with the first electrode (210) of the first light-emitting region (EMA1) in a third direction, and other parts of the unit light-emitting elements (300) are placed in the second light-emitting region (EMA2) so as to overlap with the first electrode (210) of the second light-emitting region (EMA2) in a third direction.

[0170] The third light-emitting element unit (LS3) may be a light-emitting element unit in which at least some of the plurality of unit light-emitting elements (300) included in the third light-emitting element unit (LS3) are placed in a non-light-emitting region (NEM), and other parts are placed on the first electrode (210) of the same subpixel (SPX) that is spaced apart from each other. For example, as shown in FIG. 26, some of the unit light-emitting elements (300) included in the third light-emitting element unit (LS3) are placed in a non-light-emitting region (NEM) located between the second light-emitting region (EMA2) and the third light-emitting region (EMA3), and other parts of the unit light-emitting elements (300) are placed in the third light-emitting region (EMA3), so that they may overlap with the first electrode (210) of the third light-emitting region (EMA3) in a third direction.

[0171] The display device according to the present embodiment can be formed such that a plurality of light-emitting element units (LS) are randomly arranged on a substrate (SUB) on which a first electrode (210) is formed by spraying ink without forming a separate electric field in an inkjet process for arranging the plurality of light-emitting element units (LS). However, even in this case, although a plurality of unit light-emitting elements (300) included within the same light-emitting element unit (LS) are arranged in different sub-pixels (SPX), the two ends of the unit light-emitting element (300) and the first electrode (210) and second electrode (220) of each sub-pixel (SPX) are electrically connected so that light can be emitted from the unit light-emitting element (300).

[0172] FIG. 28 is a plan view showing one pixel of a display device according to another embodiment. FIG. 29 is a cross-sectional view showing one example cut along the V-V' line of FIG. 28.

[0173] Referring to FIGS. 28 and 29, the display device (10) according to the present embodiment differs from the embodiment of FIGS. 13 and 14 in that it further includes a bank (600).

[0174] Specifically, the bank (600) may be placed at the boundary of each subpixel (SPX). The bank (600) may be arranged in a grid pattern including a portion extending in a first direction (DR1) and a second direction (DR2) on a plane. The second bank (600) may perform the function of preventing ink containing the light-emitting element unit (LS) from overflowing into adjacent subpixels (SPX) during the inkjet printing process for placing the light-emitting element unit (LS) during the manufacturing process of the display device (10), and inducing the ink to settle within the light-emitting area.

[0175] A first electrode (210), a light-emitting element unit (LS), a first insulating layer (510), and a second electrode (220) may be disposed in the area partitioned by the bank (600). The bank (600) may include polyimide (PI), but is not limited thereto.

[0176] The bank (600) may be placed on the circuit layer (CCL). The bank (600) may have a structure in which at least a portion protrudes with respect to the circuit layer (CCL). The height of the bank (600) with respect to the upper surface of the circuit layer (CCL) may be greater than the height of the first insulating layer (510). Additionally, the height of the bank (600) with respect to the upper surface of the circuit layer (CCL) may be greater than the sum of the length of the unit light-emitting element (300) and the thickness of the first electrode (210).

[0177] The second insulating layer (520) can be positioned to completely cover the second electrode (220), the first insulating layer (510), and the bank (600).

[0178] In this embodiment, the display device (10) further includes a bank (600) positioned at the boundary of each subpixel (SPX), thereby allowing the ink in which a plurality of light-emitting element units (LS) are dispersed to be guided to settle at a specific location when the ink is sprayed. Accordingly, by the bank (600) guiding the ink to settle at a specific location, the ink can settle into the light-emitting region (EMA) of each subpixel (SPX), and the plurality of light-emitting element units (LS) dispersed within the ink can be placed within the light-emitting region (EMA) of the subpixel (SPX). Accordingly, by guiding the plurality of light-emitting element units (LS) to be placed in the light-emitting region (EMA), the number of unit light-emitting elements (300) whose first end contacts the first electrode (210) of each subpixel (SPX) can be increased, and the ratio of unit light-emitting elements (300) emitting light from the light-emitting element units (LS) can be increased. Accordingly, the amount of light emitted from each light-emitting element unit (LS) is improved, and the display quality of the display device (10) can be improved.

[0179] Additionally, a bank (600) is positioned at the boundary of each subpixel (SPX) to prevent ink containing a light-emitting element unit (LS) from overflowing into an adjacent subpixel (SPX), thereby maintaining a constant number of light-emitting element units (LS) within each subpixel (SPX). Accordingly, the intensity of light emitted from each subpixel (SPX) is generally uniform, so the display quality of the display device (10) can be improved.

[0180] FIG. 30 is a cross-sectional view showing another example cut along the V-V' line of FIG. 8.

[0181] Referring to FIG. 32, the display device (10) according to the present embodiment differs from the embodiment of FIG. 31 in that the bank (600_1) includes a partition (610) and a reflective coating layer (620).

[0182] Specifically, the bank (600_1) may include a partition (610) and a reflective coating layer (620) disposed on the partition (610). The partition (610) has substantially the same shape as the bank (600) of FIG. 31. The reflective coating layer (620) is disposed on the upper surface and side surface of the partition (610). The reflective coating layer (620) may cover both the upper surface and side surface of the partition (610).

[0183] The reflective coating layer (620) may include a highly reflective material such as metal. In an exemplary embodiment, the reflective coating layer (620) may include materials such as silver, copper, aluminum, nickel, lanthanum or alloys thereof, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), ITZO (Indium Tin-Zinc Oxide), etc., but is not limited thereto. The reflective coating layer (620) may be directly deposited or coated on one surface of the partition wall (610). As another example, the reflective coating layer (620) may be attached to the partition wall (610) via an adhesive layer using a separate member.

[0184] A portion of the light traveling from the unit light-emitting element (300) toward the bank (600_1) may be reflected by the reflective coating layer (620) of the bank (600_1) and travel toward the upper direction of the substrate (SUB).

[0185] Since reflection is achieved by the reflective coating layer (620), the partition wall (610) covered by it may include a non-reflective or low-reflective material. Therefore, a bank (600_1) can be formed by forming the partition wall (610) with a material that is easy to mold, such as an organic material, and then forming a reflective coating layer (620) on its surface.

[0186] In this embodiment, the bank (600_1) has a protruding structure having a height greater than the length in the extension direction of the unit light-emitting element (300) within each subpixel (SPX) and may include a reflective coating layer (620). Accordingly, the bank (600_1) can reflect light emitted from the light-emitting element unit (LS) and directed toward the side of the bank (600_1), thereby changing the direction of light propagation toward the upper direction of the substrate (SUB). The bank (600_1) can perform the function of a reflective barrier that distinguishes neighboring subpixels (SPX) and simultaneously reflects light emitted from the light-emitting element unit (LS). Accordingly, by including the bank (600) containing the reflective coating layer (620), the display device (10) can propagate light emitted from the light-emitting element unit (LS) toward the upper direction of the substrate (SUB), and thereby improve the light efficiency of the display device (10).

[0187] FIG. 31 is a cross-sectional view showing another example cut along line II' of FIG. 2. FIG. 32 is a schematic perspective view of the unit light-emitting element of FIG. 31.

[0188] Referring to FIGS. 31 and 32, the unit light-emitting element (300_1) of the device unit (LS_1) according to the present embodiment differs from the embodiment of FIG. 3 in that it further includes an insulating film surrounding the first semiconductor layer, the second semiconductor layer, and the active layer.

[0189] Specifically, the first unit light-emitting element (300A_1) may further include an insulating film (380A) surrounding a plurality of semiconductor layers (310A, 320A) and an active layer (330A). The insulating film (380A) of the first unit light-emitting element (300A_1) may be arranged to surround the outer surface of the plurality of semiconductor layers (310A, 320A) and the active layer (330A). The insulating film (380A) of the first unit light-emitting element (300A_1) may be arranged to surround at least the outer surface of the active layer (330A) and may extend in one direction in which the first unit light-emitting element (300A_1) is extended. The insulating film (380A) of the first unit light-emitting element (300A_1) may perform the function of protecting the plurality of semiconductor layers (310A, 320A) and the active layer (330A).

[0190] Likewise, the second unit light-emitting element (300B_1) may further include an insulating film (380B) surrounding a plurality of semiconductor layers (310B, 320B) and an active layer (330B). The insulating film (380B) of the second unit light-emitting element (300B_1) may be arranged to surround the outer surface of the plurality of semiconductor layers (310B, 320B) and the active layer (330B). The insulating film (380B) of the second unit light-emitting element (300B_1) may be arranged to surround at least the outer surface of the active layer (330B) and may extend in one direction in which the second unit light-emitting element (300B_1) is extended. The insulating film (380B) of the second unit light-emitting element (300B_1) may perform the function of protecting the plurality of semiconductor layers (310B, 320B) and the active layer (330B).

[0191] Although not limited thereto, the insulating films (380A, 380B) of the first unit light-emitting element (300A_1) and the second unit light-emitting element (300B_1) can be formed simultaneously through the same process.

[0192] At least a portion of the outer surface of the insulating film (380A, 380B) may be in contact with the binder (400). The insulating film (380A, 380B) may be interposed between the first semiconductor layer (310A, 310B), the second semiconductor layer (320A, 320B), and the active layer (330A, 330B) of the unit light-emitting element (300_1) and the binder (400). In this embodiment, the first semiconductor layer (310A, 310B), the second semiconductor layer (320A, 320B), and the active layer (330A, 330B) and the binder (400) may be positioned spaced apart from each other. However, even in this case, the binder (400) is positioned to contact and wrap around the outer surface of the insulating film (380A, 380B), so that the unit light-emitting element (300_1) can be fixed by the binder (400).

[0193] In the drawing, insulating films (380A, 380B) are shown extending in the longitudinal direction of the unit light-emitting element (300_1) to cover from the first semiconductor layer (310A, 310B) to the side of the second semiconductor layer (320A, 320B), but are not limited thereto. For example, insulating films (380A, 380B) may be formed to surround the side portions of the members, but at least one end of the two ends in the longitudinal direction of the unit light-emitting element (300_1) may be exposed. The insulating films (380A, 380B) may be formed with a rounded upper surface in cross-section in an area adjacent to at least one end of the unit light-emitting element (300_1).

[0194] The insulating film (380A, 380B) may include materials having insulating properties, such as silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy), aluminum nitride (AlN), aluminum oxide (AlxOy), etc. Since the insulating film (380A, 380B) protects the outer surface of a plurality of semiconductor layers including the active layer (330A, 330B), it can prevent a decrease in luminous efficiency.

[0195] The insulating film (380A, 380B) may include a material having a refractive index different from that of the binder (400) among the materials having the insulating properties. The insulating film (380A, 380B) may include a material having a refractive index higher than that of the binder (400). By including a material having a refractive index higher than that of the binder (400) in the insulating film (380A, 380B), light emitted from the outer surface of the unit light-emitting element (300_1) and traveling toward the binder (400) may be totally reflected, thereby preventing light from being emitted to the outside of the unit light-emitting element (300_1). That is, by placing a material having a refractive index that falls within the range between the refractive indices of the unit light-emitting element (300_1) and the binder (400) between the unit light-emitting element (300_1) and the binder (400), light emitted from the outer surface of the unit light-emitting element (300_1) toward the binder (400) can be emitted smoothly without total reflection.

[0196] In this embodiment, by forming insulating films (380A, 380B) on the outer surface of a unit light-emitting element (300_1), the insulating films (380A, 380B) can function to protect a plurality of components of the unit light-emitting element (300_1). Therefore, since the insulating films (380A, 380B) protect the outer surface of a plurality of semiconductor layers and active layers of the unit light-emitting element (300_1), a decrease in light-emitting efficiency can be prevented. In addition, by forming the insulating films (380A, 380B) with a material having a refractive index higher than that of the binder (400) and lower than that of other components included in the unit light-emitting element (300_1), total reflection can be prevented, thereby preventing a decrease in the light-emitting efficiency of the display device (10).

[0197] FIGS. 33 to 36 are cross-sectional views showing the manufacturing process of the light-emitting element unit of FIG. 31.

[0198] First, referring to FIG. 33, an insulating material layer (3800) is formed on a semiconductor structure.

[0199] Specifically, the semiconductor structure may include a first semiconductor structure comprising a first semiconductor layer (310A), an active layer (330A), and a second semiconductor layer (320A) sequentially stacked along the Z direction (Z), and a second semiconductor structure comprising a second semiconductor layer (320B), an active layer (330B), and a second semiconductor layer (320B) sequentially stacked along the Z direction (Z). An insulating material layer (3800) may be formed on the front surface of the lower substrate (1000) and may be formed on the upper surface of the buffer material layer (1200) exposed by the first and second semiconductor structures as well as on the outer surface of the first and second semiconductor structures. The outer surface of the first and second semiconductor structures may include the side and upper surfaces of the first and second semiconductor structures. The insulating material layer (3800) may correspond to the insulating film (380A, 380A) described above.

[0200] Next, referring to FIG. 34, a portion of the insulating material layer (3800) is partially removed to form a plurality of unit light-emitting elements (300_1) including first and second unit light-emitting elements (300A_1, 300B_1).

[0201] Specifically, a portion of the insulating material layer (3800) may be partially removed so that the insulating material layer (3800) exposes the upper surface of the first and second semiconductor structures while surrounding the sides. In this process, a portion of the insulating material layer (3800) may be removed to expose the upper surface of the first and second semiconductor structures. The process of partially removing the insulating material layer (3800) may be performed by a process such as dry etching or etchback, which is anisotropic etching. In the process of partially removing the insulating material layer (3800), a portion of the insulating material layer (3800) placed on the buffer material layer (1200) exposed in the area where the first and second semiconductor structures are separated may also be partially removed.

[0202] Next, referring to FIG. 35, a binder material layer (4000) is formed on a lower substrate (1000) to surround the outer surface of a plurality of unit light-emitting elements (300_1).

[0203] A binder material layer (4000) may be formed to surround a plurality of unit light-emitting elements (300_1) on a lower substrate (1000). The binder material layer (4000) may come into contact with the outer surface of the insulating film (380A, 380B) of the first and second unit light-emitting elements (300A_1, 300B_1). The binder material layer (4000) may be formed to expose the upper portion of the unit light-emitting element (300_1). Specifically, the thickness of the binder material layer (4000) in the Z direction may be smaller than the length in the extension direction of the unit light-emitting element (300_1). Accordingly, the second semiconductor layer (320A) located at the top of the first unit light-emitting element (300A_1) and the first semiconductor layer (310B) located at the top of the second unit light-emitting element (300B_1) can be exposed by the binder material layer (4000).

[0204] Next, referring to FIG. 36, a light-emitting element structure (LS'_1) comprising a plurality of unit light-emitting elements (300_1) and a binder material layer (4000) is separated from a lower substrate (1000).

[0205] Specifically, the light-emitting element structure (LS'_1) may include first and second unit light-emitting elements (300A_1, 300B_1) comprising insulating films (380A, 380B) and a binder material layer (4000). The method of separating the light-emitting element structure (LS'_1) from the lower substrate (1000) during the manufacturing process of the light-emitting element unit (LS_1) is not particularly limited. The process of separating the light-emitting element structure (LS'_1) from the lower substrate (1000) may be performed by a physical separation method or a chemical separation method, etc. The lower surface of the binder material layer (4000) and the lower surface of the unit light-emitting elements (300A_1, 300B_1) may be disposed on the same plane. Next, the thickness of the binder material layer (4000) is reduced by deterioration or hardening, so that the binder material layer (4000) can form a binder (400) that exposes both ends of the unit light-emitting element (300_1) as shown in FIG. 31.

[0206] FIG. 37 is a plan view of a light-emitting element unit according to another embodiment. FIG. 38 is a cross-sectional view showing an example cut along the line VI-VI' of FIG. 37.

[0207] Referring to FIGS. 37 and 38, the light-emitting element unit (LS_2) according to the present embodiment differs from the light-emitting element unit (LS) of FIGS. 2 and 3 in that the direction in which the plurality of layers included in the plurality of unit light-emitting elements (300_2) are stacked is all the same.

[0208] Specifically, the light-emitting element unit (LS_2) may include a plurality of unit light-emitting elements (300_2) and a binder (400) that encloses the plurality of unit light-emitting elements (300_2). Each unit light-emitting element (300_2) may have a shape that extends in the Z direction (Z), and the plurality of unit light-emitting elements (300_2) may be spaced apart from each other in the X direction (X) and / or Y direction (Y) perpendicular to the Z direction (Z).

[0209] A plurality of unit light-emitting elements (300_2) may include a first semiconductor layer (310), a second semiconductor layer (320), and an active layer (330) disposed between the first semiconductor layer (310) and the second semiconductor layer (320). A unit light-emitting element (300_2) included in a light-emitting element unit (LS_2) according to the present embodiment may include a first semiconductor layer (310), an active layer (330), and a second semiconductor layer (320) sequentially stacked in the Z direction (Z). That is, the stacking direction of the plurality of layers included in the plurality of unit light-emitting elements (300_2) of the light-emitting element unit (LS_2) may be the same as each other. In the present specification, the meaning of "the stacking direction of a plurality of layers of a unit light-emitting element (300_2) is the same as each other" may mean that the unit light-emitting elements (300_2) are arranged such that the type of semiconductor layer disposed at the upper part (the end on one side of the Z direction (Z)) of each unit light-emitting element (300_2) is the same as each other, and the type of semiconductor layer disposed at the lower part (the end on the other side of the Z direction (Z)) of each unit light-emitting element (300_2) is the same as each other. For example, a second semiconductor layer (320) may be located at the upper part (the end on one side of the Z direction (Z)) of a unit light-emitting element (300_2) included in a light-emitting element unit (LS_2), and a first semiconductor layer (310) may be located at the lower part (the end on the other side of the Z direction (Z)) of a unit light-emitting element (300_2).

[0210] In this embodiment, the manufacturing process of the light-emitting element unit (LS_2) may omit the patterning process for making the stacking direction different. Specifically, the light-emitting element unit (LS_2) according to this embodiment, which includes a plurality of unit light-emitting elements (300_2) with the same stacking direction, may omit the patterning process for making the stacking direction different during the manufacturing process of the light-emitting element unit (LS) of FIGS. 2 and FIGS. 3, which includes first and second unit light-emitting elements (300A, 300B) with different stacking directions. Accordingly, the manufacturing process efficiency of the light-emitting element unit (LS_2) according to this embodiment may be improved by including a plurality of unit light-emitting elements (300_2) in which the stacking directions of the layers are the same.

[0211] Although embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention may be implemented in other specific forms without changing the technical concept or essential features thereof. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. Explanation of the symbols

[0213] 10: Display device LS: Light-emitting element unit 300: Unit light-emitting element 400: Binder 210: First electrode 220: Second electrode

Claims

Claim 1 delete Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 delete Claim 7 delete Claim 8 A substrate; a first electrode disposed on the substrate; a second electrode disposed on the first electrode spaced apart from the first electrode in the thickness direction of the substrate; The apparatus comprises a first light-emitting element unit and a second light-emitting element unit disposed between the first electrode and the second electrode, wherein the first light-emitting element unit and the second light-emitting element unit are spaced apart from each other, and the first light-emitting element unit and the second light-emitting element unit each comprise a plurality of unit light-emitting elements having a shape extended in a first direction and spaced apart from each other in a second direction perpendicular to the first direction, and a binder formed to surround the plurality of unit light-emitting elements and fixing the plurality of unit light-emitting elements, wherein each of the plurality of unit light-emitting elements comprises a first semiconductor layer, a second semiconductor layer, and an active layer disposed between the first semiconductor layer and the second semiconductor layer, and the plurality of unit light-emitting elements comprises a first unit light-emitting element in which the first semiconductor layer, the active layer, and the second semiconductor layer are sequentially disposed along the first direction, and a second unit light-emitting element in which the second semiconductor layer, the active layer, and the first semiconductor layer are sequentially disposed along the first direction, and a first unit light-emitting element in each of the first and second light-emitting element units. A display device in which the number of elements and the number of second unit light-emitting elements are the same, and a plurality of unit light-emitting elements of the first light-emitting element unit overlap with the first electrode, a plurality of unit light-emitting elements of the first group among a plurality of unit light-emitting elements included in the second light-emitting element unit overlap with the first electrode, and a plurality of unit light-emitting elements of the second group among a plurality of unit light-emitting elements included in the second light-emitting element unit do not overlap with the first electrode. Claim 9 In claim 8, a display device in which the first direction and the thickness direction of the substrate are parallel. Claim 10 In claim 8, the unit light-emitting element comprises a first end electrically connected to the first electrode and a second end electrically connected to the second electrode, forming a display device. Claim 11 A display device according to claim 10, wherein the first end of the unit light-emitting element is located at the lower end of the light-emitting element along the first direction, and the second end of the unit light-emitting element is located at the upper end of the light-emitting element along the first direction. Claim 12 A display device according to claim 11, wherein the first end of the unit light-emitting element contacts the first electrode and the second end of the unit light-emitting element contacts the second electrode. Claim 13 A display device according to claim 10, further comprising a first insulating layer disposed on the first electrode and surrounding at least one region of the light-emitting element unit, wherein the second electrode is disposed on the first insulating layer. Claim 14 In claim 13, the first insulating layer is a display device that exposes the second end of the plurality of unit light-emitting elements. Claim 15 In claim 8, a display device in which the thickness of the binder in the first direction is smaller than the length of the unit light-emitting element in the first direction. Claim 16 In claim 15, the binder is a display device that exposes both ends of the unit light-emitting element. Claim 17 In claim 16, the first unit light-emitting element and the second unit light-emitting element are arranged alternately along the second direction in a display device. Claim 18 In claim 8, the second electrode is a display device that overlaps with the first electrode in the thickness direction of the substrate. Claim 19 delete Claim 20 In claim 8, the second light-emitting element unit comprises a unit light-emitting element in which at least one of the two ends is not electrically connected to at least one of the first electrode and the second electrode.

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