Method for manufacturing micro-led assembly and method for manufacturing micro-led display using same

Abstract

Disclosed are a method for manufacturing a micro-LED assembly and a method for manufacturing a micro-LED display using same, in which assembly efficiency of micro-LEDs can be improved by applying a voltage and locally emitting light at the same time. The method for manufacturing a micro-LED assembly according to the present invention comprises the steps of: (a) preparing a substrate including first electrodes and second electrodes spaced apart from each other, and an insulating layer disposed on the first electrodes and the second electrodes and having grooves formed between the first electrodes and the second electrodes; (b) supplying a fluid containing micro-LEDs onto the substrate; and (c) generating an electric field by applying a voltage to the first electrodes and the second electrodes, and assembling the micro-LEDs into the grooves by emitting light to the grooves.

Description

Method for manufacturing a micro LED assembly and a method for manufacturing a micro LED display using the same

[0001] The present invention relates to a method for manufacturing a micro LED assembly that can improve the assembly efficiency of a micro LED by applying voltage and simultaneously irradiating light locally, and a method for manufacturing a micro LED display using the same.

[0002] The research task information of the present invention is as follows.

[0003] 1. Sub-project No.: 00467525, Ministry: Ministry of SMEs and Startups, Specialized Agency: Korea Technology Information Promotion Agency for SMEs, Research Project Name: Startup Growth Technology Development Program (Didimdol), Research Project Title: Development of Submicron Ultra-small LED-based Fluid-based Transfer Technology and Display Panel Fabrication Technology, Performing Agency: Advanced View Technology, Research Period: 2024.08.01-2025.07.31

[0004] 2. Sub-project No.: 20018235, Ministry: Ministry of Trade, Industry and Energy, Specialized Agency: Korea Institute of Industrial Technology Planning and Evaluation, Research Project Name: Manufacturing-based Production Systems, Research Title: Development of a 30nm-class In-line UV Nanoimprinter for Nano-optical Device Patterning, Performing Agency: Advanced Vue Technology, Research Period: 2023.01.01-2024.12.31

[0005] LEDs are semiconductor light-emitting devices that convert electric current into light, and due to their high light conversion efficiency, they are widely used as the light source for displays.

[0006] Recently, research is underway to apply ultra-small LED devices, fabricated in nanometer or micrometer sizes, to lighting, displays, and the like.

[0007] Micro LEDs have the advantages of higher power efficiency and shorter response times compared to conventional LEDs and OLEDs. In addition, Micro LEDs have a long lifespan and high luminous brightness.

[0008] Accordingly, Micro LED can be applied to products such as smartwatches, VLC (Visible Light Communication), automotive electronic components, and HMD (Head Mounted Display). In addition, Micro LED can be applied to ultra-high-resolution TVs, smart glasses, and AR (Augmented Reality) glasses that require a high number of pixels per unit area.

[0009] To improve the luminous efficiency of such displays, assembly technology using micro LEDs requires an alignment yield close to 100%.

[0010] However, in reality, defects occur during the process of assembling micro-LEDs for each pixel, and pixels without micro-LEDs act as dead pixels.

[0011] To resolve dead pixels, research is underway to resolve defective pixels by arranging multiple pixels so that the remaining pixels emit light even if some are defective.

[0012] However, since micro LEDs must ultimately be placed in every pixel, it is essential to further increase the assembly efficiency of micro LEDs and to perform a repair process to relocate micro LEDs to empty areas after the assembly stage.

[0013] The object of the present invention is to provide a method for manufacturing a micro LED assembly in which one micro LED can be placed in one pixel area without any empty area in the micro LED assembly.

[0014] In addition, the objective of the present invention is to provide a method for manufacturing a micro LED assembly with excellent assembly yield.

[0015] In addition, the objective of the present invention is to provide a method for manufacturing a micro LED assembly that can assemble a micro LED on a first electrode and a second electrode without causing physical damage to the surrounding area.

[0016] In addition, the objective of the present invention is to provide a method for manufacturing a micro LED display in which all micro LEDs can be arranged for each pixel.

[0017] The objects of the present invention are not limited to those mentioned above, and other unmentioned objects and advantages of the present invention may be understood from the following description and will be more clearly understood by the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0018] A method for manufacturing a micro LED assembly according to the present invention comprises: (a) a step of providing a substrate including a first electrode and a second electrode spaced apart from each other, and an insulating layer disposed on the first electrode and the second electrode and having a groove formed between the first electrode and the second electrode; (b) a step of supplying a fluid containing a micro LED onto the substrate; and (c) a step of applying a voltage to the first electrode and the second electrode to generate an electric field and irradiating light into the groove to assemble the micro LED in the groove.

[0019] In step (c) above, one or more types of light among visible light and infrared light may be irradiated.

[0020] After step (c) above, the method may further include step (d) applying voltage to the first electrode and the second electrode of the groove where the micro LED is not placed to generate an electric field, and irradiating light into the groove where the micro LED is not placed to reposition the micro LED.

[0021] A method for manufacturing a micro LED display according to the present invention comprises: (a) a step of placing a transistor in each of a plurality of pixel regions defined by the intersection of a data line and a gate line on a substrate; (b) a step of placing a first electrode and a second electrode spaced apart from each other on a substrate on which the transistor is placed for each of the plurality of pixel regions, and then placing an insulating layer having a groove formed between the first electrode and the second electrode; (c) a step of supplying a fluid containing a micro LED on the substrate; and (d) a step of applying a voltage to the first electrode and the second electrode to generate an electric field and irradiating light into the groove to assemble the micro LED in the groove.

[0022] In step (d) above, one or more types of light among visible light and infrared light may be irradiated.

[0023] After step (d) above, (e) a step of generating an electric field by applying voltage to the first electrode and the second electrode of the groove where the micro LED is not placed, and repositioning the micro LED by irradiating light into the groove where the micro LED is not placed.

[0024] In addition, one micro LED can be placed in each pixel area.

[0025] The method for manufacturing a micro LED assembly according to the present invention has the effect of further improving the assembly efficiency of the micro LED by means of an electric field and local light irradiation.

[0026] In addition, the method for manufacturing a micro LED assembly according to the present invention has the effect of assembling a micro LED on a first electrode and a second electrode without causing physical damage to the surrounding area.

[0027] Accordingly, the manufacturing method of a micro LED display using this allows for the placement of micro LEDs in every pixel and has the effect of achieving an excellent assembly yield of micro LEDs.

[0028] In addition to the effects described above, the specific effects of the present invention are described together with the specific details for implementing the invention below.

[0029] FIG. 1 is a flowchart illustrating a method for manufacturing a micro LED assembly according to the present invention.

[0030] FIG. 2 is a cross-sectional view showing a groove formed in the insulating layer of a micro LED assembly according to the present invention.

[0031] FIG. 3 is a plan view of a micro LED assembly with a groove formed according to the present invention.

[0032] FIG. 4 is a schematic diagram showing the steps of assembling a wire-shaped micro LED according to the present invention.

[0033] FIG. 5 is a schematic diagram showing the steps of assembling a cube-shaped micro LED according to the present invention.

[0034] FIG. 6 is a schematic diagram showing the step of assembling a cube-shaped micro LED during the manufacturing steps of a micro LED display according to the present invention.

[0035] [Explanation of the symbol]

[0036] 10 : Substrate

[0037] 21 : First electrode

[0038] 22 : Second electrode

[0039] 30: Insulating layer

[0040] 40 : Transistor

[0041] A : Home

[0042] The aforementioned objectives, features, and advantages are described in detail below with reference to the attached drawings, thereby enabling those skilled in the art to easily implement the technical concept of the present invention. In describing the present invention, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such descriptions would unnecessarily obscure the essence of the invention. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0043] In the following, the statement that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0044] In addition, where it is stated that one component is "connected," "combined," or "connected" to another component, it should be understood that while the components may be directly connected or connected to each other, another component may be "interposed" between each component, or each component may be "connected," "combined," or "connected" through another component.

[0045] Hereinafter, a method for manufacturing a micro LED assembly according to some embodiments of the present invention and a method for manufacturing a micro LED display using the same will be described.

[0046] The present invention improves the assembly yield of micro LEDs by using voltage application and light irradiation, and further has the effect of relocating micro LEDs to a home area without micro LEDs by performing a repair step after the assembly step.

[0047] A micro LED assembly refers to a material in which micro LEDs are assembled on a first electrode and a second electrode that are spaced apart from each other.

[0048] Specifically, the micro LED assembly refers to a material in which a fluid-based micro LED is assembled in a groove located on the first electrode and the second electrode by forming a strong electric field on the first electrode and the second electrode while simultaneously locally irradiating light into the groove.

[0049] Here, assembly may include the meanings of placement, alignment, array, position, and assembly.

[0050] In the present invention, the micro LED is an ultra-small light-emitting material having a longest side length of approximately 100 μm or less, and may include a nano LED. For example, the longest side length of the micro LED may be greater than 0 μm and less than or equal to 80 μm, specifically greater than 0 μm and less than or equal to 50 μm, greater than 0 μm and less than or equal to 40 μm, greater than 0 μm and less than or equal to 30 μm, greater than 0 μm and less than or equal to 20 μm, and more specifically greater than 0 μm and less than or equal to 10 μm.

[0051] Micro LEDs are organic or / or inorganic materials dispersed in a fluid and can have various sizes in 1D, 2D, or 3D shapes.

[0052] For example, micro LEDs can be in the form of nanowires with length, flat disks, or cubes with an aspect ratio of 1 to 2.

[0053] In addition, the micro LED may include a core-shell structure formed in any one of the nanowire, disk, or cube forms.

[0054] In core-shell micro LEDs, the active layer surrounds the outer surface of the n-type semiconductor layer; therefore, light can be emitted from the entire area where the active layer is located. In other words, because the active layer area of ​​a core-shell micro LED is relatively large, a large area for light emission can be secured.

[0055] A core-shell structured micro LED may include a core formed of an n-type semiconductor layer located in the center along the longitudinal direction of the micro LED, an active layer disposed on the surface of the core and surrounding at least one side of the n-type semiconductor layer, and a p-type semiconductor layer disposed on the surface of the active layer and surrounding the active layer.

[0056] Additionally, it may further include a metal layer (not shown) surrounding a p-type semiconductor layer and an insulating film (not shown) surrounding a portion of the outer surface of the metal layer, but is not limited thereto.

[0057] Micro LEDs can have a shape corresponding to the shape of the n-type semiconductor layer.

[0058] For example, a micro LED may have a hexagonal pyramid shape that tapers at a single vertex as it narrows from the center upwards, or a rectangular prism shape with a uniform width from the center downwards. As another example, a micro LED may have a polygonal prism shape that narrows from top to bottom, or conversely, a polygonal prism shape that narrows from bottom to top.

[0059] In the present invention, high density and high resolution can be achieved by fabricating a display having nano-sized pixels using various types of micro LEDs.

[0060] Micro LEDs comprise an n-type semiconductor layer, an active layer, and a p-type semiconductor layer. Since this configuration is identical to that of commonly used LEDs, a detailed explanation will be omitted.

[0061] FIG. 1 is a flowchart illustrating a method for manufacturing a micro LED assembly according to the present invention.

[0062] Referring to FIG. 1, the method for manufacturing a micro LED assembly of the present invention may include the step of providing a substrate comprising an insulating layer having a groove formed between the first electrode and the second electrode, disposed on a first electrode and a second electrode spaced apart from each other (S110); the step of supplying a fluid containing a micro LED onto the substrate (S120); and the step of applying a voltage to the first electrode and the second electrode to generate an electric field and irradiating light into the groove to assemble the micro LED in the groove (S130).

[0063] A micro LED assembly manufactured according to the above manufacturing method may include a substrate (10), a first electrode (21) and a second electrode (22) disposed on the substrate and spaced apart from each other, an insulating layer (30) disposed on the first electrode (21) and the second electrode (22) and including a groove (A), and a micro LED disposed in the groove (A) of the insulating layer.

[0064] Step (S110) of providing a substrate comprising an insulating layer disposed on a first electrode and a second electrode spaced apart from each other, with a groove formed between the first electrode and the second electrode

[0065] The substrate (10) may include a first electrode (21) and a second electrode (22) spaced apart from each other, and an insulating layer (30) disposed on the first electrode (21) and the second electrode (22) with a groove (A) formed between the first electrode and the second electrode.

[0066] Specifically, the substrate (10) includes a transparent insulating material that allows light to pass through.

[0067] For example, the substrate may include one or more of a silicon substrate, a glass substrate, a quartz substrate, a glass ceramic substrate, a crystalline glass substrate, and a plastic substrate including a polymeric organic material. Preferably, the substrate may be an active matrix backplane.

[0068] After placing a metal layer on the substrate (10), a certain area of ​​the metal layer can be removed to form the first electrode (21) and the second electrode (22).

[0069] Generally, display circuits require a lot of metal wiring because micro LEDs must be connected to electrodes.

[0070] Accordingly, since parasitic electric fields can be generated in unwanted locations during the micro LED assembly process using electric fields, it is important to minimize this phenomenon.

[0071] To this end, a metal layer can be formed across the entire area to cover all components of the circuit, acting as an electric field shielding layer and serving as an alignment layer.

[0072] If a metal layer is formed over the entire area of ​​the substrate, the formation of parasitic electric fields can be minimized while simultaneously protecting the underlying device from the electric field.

[0073] A first electrode (21) and a second electrode (22) spaced apart from each other can be formed on a substrate by patterning the formed metal layer.

[0074] The first electrode (21) and the second electrode (22), which are spaced apart from each other, may be formed from a metal layer or may be formed by extending from either the source electrode or the drain electrode of the transistor (40).

[0075] Next, an insulating layer (30) can be placed to cover the substrate (10), the first electrode (21), and the second electrode (22). At this time, the insulating layer (30) corresponding to the gap area between the first electrode (21) and the second electrode (22) can be patterned to a uniform thickness to form a groove (A).

[0076] When a groove (A) is formed in the insulating layer (30), the groove (A) region is closer to the first electrode (21) and the second electrode (22) than the non-groove region, so when voltage is applied to the first electrode (21) and the second electrode (22), the electric field strength in the groove (A) becomes locally larger.

[0077] Accordingly, a strong attractive force is generated in the groove area, so the micro LED can be assembled in a more accurate position by the groove.

[0078] In addition, it has the effect of facilitating the assembly of micro LEDs, and allows a single micro LED to be aligned in a single pixel area.

[0079] As shown in FIGS. 2 and 3, the groove (A) refers to a ditch or trench shape, overlaps on the gap area, and can be spaced apart at regular intervals along the length direction of the gap area.

[0080] The groove (A) of the insulating layer (30) is a space where a micro LED is placed, and it is preferable that the size of the groove (A) be larger than the size of the micro LED.

[0081] By forming the size of the home (A) larger than the size of the micro LED, one micro LED can be stably assembled in one pixel area, and at the same time, the micro LED can be assembled in a fixed state inside the home.

[0082] In particular, to assemble one micro LED in one pixel area, two or more micro LEDs can be assembled in one groove, and preferably, one micro LED can be assembled in one groove.

[0083] In FIG. 3, it is illustrated that one micro LED is assembled in one groove, but it is not limited thereto, and two or more micro LEDs may be assembled in one groove.

[0084] Preferably, to assemble one micro LED in one groove, the length (D1) of the groove (A) is greater than the distance (gap) between the first electrode (21) and the second electrode (22), and is preferably less than or equal to twice the length of the micro LED.

[0085] In addition, the width (D2) of the groove (A) is larger than the diameter of the micro LED, and when repulsion occurs between multiple micro LEDs, it is preferable that it be smaller than the gap between one micro LED and another adjacent micro LED.

[0086] Here, the gap between one micro LED and another adjacent micro LED is formed by being separated by a certain distance due to repulsion when an electric field is generated, and can be controlled by the electric field strength, the coupling phenomenon caused by the coupling capacitor between the micro LED and the electrode, and the light irradiation strength described later.

[0087] As shown in FIG. 3, when observed in a plane after assembly, one end of the micro LED is placed on the first electrode and the other end is placed on the second electrode, so that a structure in which the micro LED is superimposed on the first electrode and the second electrode can be shown.

[0088] The insulating layer (30) can be formed from a polymer-based organic or / and inorganic material.

[0089] For example, the insulating layer (30) may include various materials such as Al2O3, SiO2, etc.

[0090] Meanwhile, even if there is no insulating layer on the first electrode (21) and the second electrode (22), micro LEDs are arranged on the electrode portion, but at the moment of arrangement, a high current flows, causing a short circuit and the micro LEDs may be destroyed.

[0091] Accordingly, it is preferable to place an insulating layer on the first electrode (21) and the second electrode (22).

[0092] Since the micro LED is positioned in the groove of the insulating layer, the micro LED is spaced apart from the surface of the first electrode and the surface of the second electrode.

[0093] Step (S120) of supplying a fluid containing a micro LED onto a substrate

[0094] A fluid containing a plurality of micro LEDs can be continuously supplied in a uniform amount on a substrate having electrodes (21, 22) and an insulating layer (30).

[0095] Fluid can refer to a liquid, which is a substance that can flow freely.

[0096] In addition, the fluid may be a liquid having a dielectric constant lower than that of a micro LED when an electric signal is applied by an electric signal supply unit (not shown).

[0097] The fluid may include one or more of isopropyl alcohol, acetone, toluene, ethanol, methanol, and distilled water.

[0098] The above electrical signal supply unit can supply a direct current signal, an alternating current signal, or a pulsed direct current (pulsed DC) signal to the first electrode (21) and the second electrode (22).

[0099] A pulsed DC signal can refer to a periodic electrical signal in which the value changes but the polarity remains constant.

[0100] The concentration of micro LEDs in the fluid is 10 5 ~ 10 12It may be one / L, but is not limited thereto.

[0101] A step (S130) of generating an electric field by applying voltage to the first electrode and the second electrode, and assembling a micro LED in the groove by irradiating light into the groove.

[0102] As shown in FIGS. 4 and 5, a voltage is applied to the first electrode (21) and the second electrode (22) to generate an electric field, and at the same time, light is locally irradiated into the groove, so that a micro LED can be assembled in the groove.

[0103] Although wire-shaped and cube-shaped micro LEDs are illustrated in FIGS. 4 and 5, the invention is not limited thereto, and disk-shaped micro LEDs may be used, or selected from core-shell structured nanowires, core-shell structured disks, and core-shell structured cube-shaped micro LEDs may be used.

[0104] Specifically, voltage can be applied to the first electrode (21) and the second electrode (22) and light can be irradiated into the groove at the same time.

[0105] Alternatively, light can be irradiated while an electric field is generated by first applying voltage. Or, the state of first irradiating light can be maintained, and then an electric field can be generated by applying voltage.

[0106] When voltage is applied to the first electrode (21) and the second electrode (22), an electric field is formed around the first electrode (21) and the second electrode (22), attracting micro LEDs toward the first electrode (21) and the second electrode (22), and causing the micro LEDs to repel each other.

[0107] In particular, when a groove (A) is formed in the insulating layer (30), a relatively high electric field is formed in the groove (A), and a strong attractive force is generated in that part, so the assembly of the micro LED can be made easier.

[0108] Irradiating light onto the above groove may mean irradiating light locally onto the groove or irradiating light to the surrounding area including the groove.

[0109] In the present invention, when assembling a micro LED, light is irradiated into a groove, and due to the electromagnetic interaction between the electromagnetic waves generated from the light and the micro LED, the micro LED can move to the position where the light is irradiated.

[0110] The technology for assembling micro LEDs using light can utilize radiation pressure.

[0111] Radiation pressure is the static pressure generated when electromagnetic waves strike an object such as a micro LED. Photons, which are particles of light, have no mass but possess energy; therefore, when they absorb that energy, they experience pressure.

[0112] In other words, radiation pressure is the pressure generated when light strikes the surface of an object and absorbs energy.

[0113] When light is focused at a single point, a force attracting the surroundings acts upon it, enabling the micro-LEDs to be held in place through gradient force and scattering force.

[0114] Here, the force of light intensity refers to the force that causes light passing through the micro LED to converge at the point where the light intensity is strongest in the XY plane and the Z axis due to refraction.

[0115] Conversely, scattering force refers to the force that pushes the micro LED forward as light incident on the micro LED bounces off without passing through it.

[0116] The hardness force must be greater than the scattering force for the micro LED to be captured by light.

[0117] For example, insulating materials undergo transmission or refraction, so their hardness force may be greater than their scattering force, and they will attract surrounding materials. Metallic materials do not undergo transmission or refraction, so their hardness force becomes zero, and they will be pushed forward due to only their scattering force.

[0118] Meanwhile, when the micro LED is in the form of a disk or a wire, the wavelength of the electromagnetic wave may vary depending on the shape and size of the micro LED.

[0119] That is, depending on the shape and size of the micro LED, one or more types of light among visible light and infrared light can be selectively irradiated, and the light can be, for example, a laser beam, LED light, etc.

[0120] The visible light irradiated onto the micro LED may have a wavelength of 380 to 800 nm, and preferably a wavelength of 400 to 780 nm.

[0121] The infrared light irradiated onto the micro LED can have a wavelength of 780 to 1000 nm.

[0122] For light to respond to one size of a micro LED including at least one of the length, diameter, and thickness of a micro LED, the micro LED may have an emission wavelength corresponding to 0.1 to 10 times the size including at least one of the length, diameter, and thickness.

[0123] Thus, in the present invention, by generating an electric field and irradiating light while a groove is formed in the insulating layer, a relatively large attractive force is formed between the first electrode (21), the second electrode (22), and the micro LED, thereby enabling stable assembly of the micro LED without causing physical damage to the surrounding area, further improving the assembly yield, and shortening the assembly time.

[0124] After the step of assembling the micro LED, there may be cases where the micro LED is not in the groove (A) where it is to be assembled.

[0125] In this case, a repair process is required to relocate the micro LED to the groove among the grooves (A) that does not have a micro LED.

[0126] After identifying a groove in which a micro LED is not placed in a micro LED assembly, a voltage is applied to the first electrode and the second electrode of the groove in which the micro LED is not placed to generate an electric field, and light is irradiated onto the groove in which the micro LED is not placed to relocate the micro LED.

[0127] At this time, a fluid containing multiple micro LEDs can be supplied back onto the substrate as needed.

[0128] The voltage magnitude and light intensity during the repositioning step may be the same as, greater than, or smaller than the conditions during the preceding micro-LED assembly step.

[0129] The groove where the above-mentioned micro LED is not placed may include cases where a part of the micro LED is overlapping the groove where the micro LED should be, or cases where there is no micro LED in the groove.

[0130] Empty grooves can be identified using an optical method with a microscope or by the naked eye.

[0131] As such, in the manufacturing method of the micro LED assembly of the present invention, by utilizing an electric field and light while grooves are formed in the insulating layer, one micro LED can be assembled for each pixel, thereby maximizing assembly efficiency and repair efficiency.

[0132] A method for manufacturing a micro LED display using the method for manufacturing a micro LED assembly of the present invention will be described.

[0133] A transistor (40) can be placed in each of a plurality of pixel regions defined by the intersection of a data line and a gate line on a substrate (10).

[0134] In displays, transistors regulate the current of micro LEDs and play a role in controlling the brightness of each pixel that makes up the display screen.

[0135] The transistor (40) can be placed in each of a plurality of pixel regions defined by the intersection of data lines and gate lines on a substrate. Additionally, the transistor may be a thin-film transistor using a thin film in the form of a relatively thin film.

[0136] One pixel consists of subpixels that make up R, G, and B, and for the display to produce color, current is required for each subpixel.

[0137] Transistors are located in each subpixel and drive the pixel with a corresponding amount of current when a specific voltage is applied.

[0138] A transistor (40) may be composed of an active layer, a gate electrode responsible for turning the active layer on / off, a source electrode and a drain electrode that allow current to flow directly, and a gate insulating film for insulation between the gate electrode and the active layer.

[0139] The data line is connected to the source electrode of the transistor, and the gate line can be connected to the gate electrode of the transistor.

[0140] Next, a first electrode (21) and a second electrode (22) spaced apart from each other are placed on a substrate on which a transistor (40) is placed for each of the multiple pixel regions, and then an insulating layer (30) can be placed on the first electrode (21) and the second electrode (22).

[0141] At this time, after stacking the electrode layers surrounding the transistor (40), the first electrode (21) and the second electrode (22) can be formed by removing the portion corresponding to the gap region among the electrode layers.

[0142] To increase the assembly efficiency of the micro LED, a groove (A) may be formed in the insulating layer (30), and the groove (A) may be placed on the gap region between the first electrode (21) and the second electrode (22). Details regarding the first electrode (21), the second electrode (22), and the insulating layer (30) are the same as those described above, so they will be omitted.

[0143] Next, a fluid containing multiple micro LEDs can be supplied onto a substrate.

[0144] Details regarding the fluid are the same as previously mentioned, so they will be omitted.

[0145] Next, as shown in FIG. 6, a voltage is applied to the first electrode (21) and the second electrode (22) that are spaced apart from each other to generate an electric field, and light is irradiated into the groove to assemble a micro LED in the groove.

[0146] When an electric field is formed around the first electrode (21) and the second electrode (22) and light is irradiated into the groove, one of the plurality of micro LEDs can be assembled in the groove by the attractive force of the electric field and the interaction between the electromagnetic wave and the micro LED.

[0147] The assembled micro LED is placed on a first electrode (21) and a second electrode (22) that are spaced apart from each other, and can be electrically connected to the first electrode (21) and the second electrode (22).

[0148] Details regarding voltage application and light irradiation are the same as those previously mentioned, so they will be omitted.

[0149] Subsequently, after identifying empty grooves, the method may further include the step of generating an electric field by applying voltage to the first and second electrodes of the grooves where the micro LEDs are not placed, and repositioning the micro LEDs by irradiating light into the grooves where the micro LEDs are not placed.

[0150] The details regarding the repositioning of the micro LEDs are the same as those previously mentioned, so they will be omitted.

[0151] In this way, when assembling micro LEDs, the assembly efficiency can be maximized through the interaction between the electric field, electromagnetic waves, and the micro LEDs, and it has the effect of assembling one micro LED per pixel area.

[0152] Meanwhile, in order to arrange micro LEDs with different light-emitting characteristics, such as micro LEDs corresponding to RGB colors, as display pixels on a display backplane, the micro LEDs can be assembled by applying voltage and irradiating light to each row among a plurality of rows.

[0153] At this time, a circuit device capable of individually applying an electric signal to sequentially apply voltage to each column can be used.

[0154] To implement RGB full color, voltage application and light irradiation are applied to each pixel, and micro LEDs can be assembled in the following way regardless of the order.

[0155] While supplying a fluid containing a red micro LED among a plurality of micro LEDs, an electrical signal is applied to a first electrode connected to a red pixel and a second electrode to arrange the red micro LED in a groove included in the red pixel, and then the red micro LED is repositioned by applying an electrical signal and irradiating light to a groove without a red micro LED, and then the substrate can be dried.

[0156] While supplying a fluid containing a green micro LED among a plurality of micro LEDs, an electrical signal is applied to a first electrode connected to a green pixel and a second electrode to arrange the green micro LED in a groove included in the green pixel, and then the green micro LED is repositioned by applying an electrical signal and irradiating light to a groove without a green micro LED, and then the substrate can be dried.

[0157] While supplying a fluid containing a blue micro LED among a plurality of micro LEDs, an electrical signal is applied to a first electrode connected to a blue pixel and a second electrode to arrange the blue micro LED in a groove included in the blue pixel, and then the blue micro LED is repositioned by applying an electrical signal and irradiating light to a groove without a blue micro LED, and then the substrate can be dried.

[0158] In this way, a full-color display can be completed by repeating the fluid supply, micro LED assembly, repair, and drying steps to form an RGB micro LED assembly on the display.

[0159] As another example, to arrange micro LEDs corresponding to RGB colors as display pixels on a display backplane, among a plurality of columns, a groove is formed in one column, and then voltage is applied and light is irradiated to assemble the micro LEDs in the groove; a micro LED that is not assembled in the groove is removed; and a groove is formed in another column, and then voltage is applied and light is irradiated to assemble the micro LEDs in the groove.

[0160] In at least one of the steps immediately after the step of assembling a micro LED in the above-mentioned groove and immediately after the step of removing a micro LED not assembled in the above-mentioned groove, a step of relocating the micro LED by applying voltage and irradiating light to the groove without the micro LED may be further performed.

[0161] By repeating this process, RGB full-color displays can be manufactured in multiple columns.

[0162] Subsequently, a step of removing the portions below both ends of the micro LED from the insulating layer can be performed. In this step, etching can be performed using photoresist (PR), but is not limited thereto.

[0163] Subsequently, a step of forming a first fixed electrode extending upward from the first electrode and a second fixed electrode extending upward from the second electrode in the region where the insulating layer has been removed may be performed.

[0164] At this stage, a first fixed electrode and a second fixed electrode can be formed by depositing metal or electroplating.

[0165] Afterwards, the step of connecting both ends of the micro LED to the first fixed electrode and the second fixed electrode can be performed.

[0166] One end of the micro LED can be electrically connected to the first electrode (21) through the first fixed electrode and physically fixed.

[0167] Likewise, the other end of the micro LED can be electrically connected to the second electrode (22) through the second fixed electrode and physically fixed.

[0168] The first fixed electrode and the second fixed electrode are spaced apart from each other, and a micro LED can be spaced apart from the upper surface of the first electrode and the upper surface of the second electrode.

[0169] From this perspective, since the micro LED is spaced apart from the substrate surface, it can provide a heat dissipation effect.

[0170] Afterwards, one of the first electrode (21) and the second electrode (22) is connected to the source electrode or drain electrode of the transistor (40), and the other of the first electrode (21) and the second electrode (22) is connected to the power supply voltage line (V DD It may further include a step of connecting to ) or base voltage line (Vss).

[0171] The first electrode (21) and the second electrode (22) are formed by patterning a metal layer, and after the coupling step of the micro LED, the source electrode, drain electrode, first electrode, and second electrode of the transistor can all be formed from the metal layer.

[0172] And through the connecting step, one end of the micro LED is connected to the source electrode of the transistor, and the other end of the micro LED is connected to the power supply voltage line (V DD It can be connected to ).

[0173] The micro LED display of the present invention can be applied to small and high-resolution displays, and can also be applied to head-mounted displays (HMDs) for augmented reality and virtual reality (AR-VR) and head-up displays (HUDs) applied to automobiles.

[0174] In addition, micro LED displays can be utilized in various fields such as optical sensors, optical communication, semiconductor integration, automotive headlamps, smart textiles, bio-contact lenses, and light sources for wearable medical devices.

[0175] Although the present invention has been described above with reference to the illustrated drawings, the present invention is not limited by the embodiments and drawings disclosed in this specification, and it is obvious that various modifications can be made by a person skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration according to the present invention were not explicitly described while explaining the embodiments of the present invention above, it is natural to acknowledge that the effects predictable by said configuration should also be recognized.

Claims

1. (a) A step of providing a substrate comprising a first electrode and a second electrode spaced apart from each other, and an insulating layer disposed on the first electrode and the second electrode and having a groove formed between the first electrode and the second electrode; (b) supplying a fluid containing a micro LED onto the substrate; and (c) a step of generating an electric field by applying voltage to the first electrode and the second electrode, and assembling a micro LED in the groove by irradiating light into the groove; a method for manufacturing a micro LED assembly.

2. In Paragraph 1, A method for manufacturing a micro LED assembly by irradiating one or more types of light among visible light and infrared light in step (c) above.

3. In Paragraph 1, After step (c) above, (d) a step of generating an electric field by applying voltage to the first electrode and the second electrode of the groove where the micro LED is not placed, and repositioning the micro LED by irradiating light into the groove where the micro LED is not placed; further comprising a method for manufacturing a micro LED assembly.

4. (a) A step of placing transistors in each of a plurality of pixel regions defined by the intersection of data lines and gate lines on a substrate; (b) a step of placing a first electrode and a second electrode spaced apart from each other on a substrate on which a transistor is placed for each of the plurality of pixel regions, and then placing an insulating layer with a groove formed between the first electrode and the second electrode; (c) supplying a fluid containing a micro LED onto the substrate; and (d) a step of generating an electric field by applying voltage to the first electrode and the second electrode, and assembling a micro LED in the groove by irradiating light into the groove; a method for manufacturing a micro LED display.

5. In Paragraph 4, A method for manufacturing a micro LED display by irradiating one or more types of light among visible light and infrared light in step (d) above.

6. In Paragraph 5, After step (d) above, (e) a step of generating an electric field by applying voltage to the first electrode and the second electrode of the groove where the micro LED is not placed, and repositioning the micro LED by irradiating light into the groove where the micro LED is not placed; further comprising a method for manufacturing a micro LED display.

7. In Paragraph 4, A method for manufacturing a micro LED display in which one micro LED is placed in each pixel area.

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