Apparatus and method of transfering LED

Abstract

The present specification discloses a light-emitting diode (LED) transfer device. The LED transfer device comprises: a head configured to lift an LED on one substrate and lower the LED onto another substrate; a transport arm configured to move the head; a cover configured to provide a sealed space accommodating the head and the one substrate or the other substrate; and a control unit configured to regulate the air pressure of the sealed space provided by the cover.

Description

Technology Field

[0001] This specification relates to an LED transfer device and an LED transfer method using said device. Background Technology

[0002] Liquid crystal displays and organic light-emitting diodes (OLEDs) are widely applied to the screens of everyday electronic devices, such as mobile phones and laptops, and their scope is gradually expanding. However, these display devices have limitations in reducing the size of the bezel area. For example, in the case of liquid crystal displays, a sealant must be used to seal the liquid crystal and bond the upper and lower substrates, which limits the reduction of the bezel area. Additionally, in the case of OLEDs, since the organic light-emitting diodes are made of organic materials and are highly vulnerable to moisture or oxygen, an encapsulation must be placed to protect the organic light-emitting diodes, which limits the reduction of the bezel area. Consequently, when implementing an extra-large screen by arranging multiple liquid crystal displays or OLEDs in a tile form, there is a problem in that the bezel area between adjacent panels is easily visible to the user.

[0003] As an alternative to this, display devices using small LEDs as light-emitting elements are being researched. Since LEDs are composed of inorganic materials rather than organic materials, they offer excellent reliability and have a longer lifespan compared to liquid crystal displays or organic light-emitting displays. Furthermore, LEDs are suitable for application in ultra-large screens because they not only have a fast lighting speed but also consume less power, offer superior stability due to strong shock resistance, and can display high-brightness images. Above all, display devices using small LEDs as light-emitting elements can be implemented without bezels, making them advantageous for application in ultra-large displays that are manufactured by connecting multiple display devices.

[0004] Since securing productivity is essential for the commercialization of such small LED displays, various studies are being conducted to increase production speed and efficiency. The problem to be solved

[0005] The present specification aims to propose a method and equipment capable of improving the production efficiency of small LED display devices. More specifically, it aims to provide an LED transfer device that is faster and safer than the prior art. The problems described in this specification are not limited to those mentioned above, and other unmentioned problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0006] An LED transfer device according to one embodiment of the present specification comprises: a head configured to lift an LED on one substrate and lower the LED to another substrate; a transport arm for moving the head; a cover configured to provide a sealed space for accommodating the head and the one substrate or the other substrate; and a control unit for controlling the air pressure of the sealed space provided by the cover.

[0007] The LED transfer device may further include a support member configured to place the one substrate or the other substrate on its upper surface and to provide the sealed space together with the cover.

[0008] The head may include a plate connected to the transport arm; and a stamp having one side bonded to the plate and the other side provided to contact the LED, with a micro-groove. The stamp may be an elastomer having a predetermined elasticity, and the micro-groove may have a diameter of 10 micrometers (μm) or less.

[0009] The above control unit may be configured to make the pressure of the sealed space one of atmospheric pressure, a first pressure lower than atmospheric pressure, and a second pressure lower than the first pressure.

[0010] A method for transferring an LED to another substrate, according to another embodiment of the present specification, comprises the steps of: positioning one surface of a head having a microgroove on the upper surface of an LED on the first substrate at a reference pressure; providing a first sealed space including the first substrate and the head, lowering the pressure inside the first sealed space to a first pressure lower than the reference pressure, and bringing the head into contact with the upper surface of the LED; raising the pressure inside the first sealed space to the reference pressure and lifting the head to separate the LED from the first substrate; positioning the separated LED and the head holding the LED on the upper surface of the other substrate; lowering the head to bring the LED into contact with the other substrate; providing a second sealed space including the other substrate and the head holding the LED, and lowering the pressure inside the second sealed space to a second pressure lower than the first pressure to release the attachment between the head and the LED. It may include the step of lifting the head and raising the pressure inside the second sealed space to the reference pressure.

[0011] Specific details of other embodiments are included in the detailed description and drawings. Effects of the invention

[0012] The LED transfer device and transfer method according to the embodiments of this specification can reduce LED damage in the process and also increase the transfer speed. This can lead to increased productivity of LED display devices. The effects according to the embodiments of this specification are not limited to those exemplified above, and a wider variety of effects are included within this specification. Brief explanation of the drawing

[0013] FIG. 1 is a schematic plan view of an LED display device according to one embodiment of the present specification. FIG. 2 is a cross-sectional view showing a display area of ​​an LED display device according to one embodiment of the present specification. FIG. 3 is a diagram showing the structure of an LED according to one embodiment of the present specification. FIGS. 4a and 4b are simplified drawings of an LED transfer device according to one embodiment of the present specification. FIGS. 5a to 5i are drawings illustrating an LED transfer method according to one embodiment of the present specification. Specific details for implementing the invention

[0014] The advantages and features of this specification 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.

[0015] Shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of this specification are exemplary and are not limited to the details illustrated in this specification. Throughout the specification, the same reference numerals refer to the same components. Furthermore, in describing the present invention, if it is determined that a detailed description of related prior art could unnecessarily obscure the essence of the invention, such detailed description is omitted. Where terms such as "includes," "has," or "is made up" are used in this specification, other parts may be added unless "only" is used. When a component is expressed in the singular, it includes cases where it is included in the plural unless specifically stated otherwise. In interpreting components, they are interpreted to include an error range even without separate explicit description.

[0016] In the case of descriptions of positional relationships, for example, where the positional relationship between two parts is described using expressions such as 'on,' 'above,' 'below,' or 'next to,' one or more other parts may be located between the two parts unless 'immediately' or 'directly' is used. When an element or layer is referred to as being "on" another element or layer, this includes cases where another layer or element is interposed directly on the other element or in the middle. Where it is stated that a component is "connected," "coupled," or "joined" to another component, it should be understood that the component may be directly connected or joined to the other component, but that another component may be "interposed" between each component, or that each component may be "connected," "coupled," or "joined" through the other component.

[0017] Although terms such as "first," "second," etc., are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another. Accordingly, the first component mentioned below may be the second component within the technical scope of the present invention.

[0018] The size and thickness of each component shown in the drawings are illustrated for convenience of explanation, and the present invention is not necessarily limited to the size and thickness of the illustrated components. Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings.

[0019] FIG. 1 is a schematic plan view of an LED display device according to one embodiment of the present specification.

[0020] The LED display device (100) may be composed of a plurality of pixels (P) arranged on a substrate (110). The pixels (P) may include a red subpixel (140R), a green subpixel (140G), and a blue subpixel (140B).

[0021] Each of the above subpixels (140R, 140G, 140B) may be equipped with a thin-film transistor (TFT) and an LED (140) as a driving element and a light-emitting element. The LED (140) and the thin-film transistor may be connected to a driving unit, such as a gate control circuit or a data control circuit, through wiring such as a gate line or a data line. If the chip size (width) of the LED (140) is 100 micrometers (μm) or less, it may be referred to as a micro LED display. Meanwhile, if the chip size of the LED (140) is about several hundred micrometers, it may be referred to as a mini LED display.

[0022] The above LED (140) can be manufactured separately from the array process of the substrate (110). In an organic light-emitting display device, both the TFT and the light-emitting element are formed by a photolithography process, whereas in an LED display device, the TFT is formed by a photolithography process, but the LED (140) can be manufactured by a separate process and then transferred onto the substrate (110). As an example, the above LED (140) can be obtained by growing an inorganic material such as Al, Ga, N, P, As, or In on a growth substrate (sapphire substrate or silicon substrate) and then separating it from the growth substrate.

[0023] FIG. 2 is a cross-sectional view showing a display area of ​​an LED display device according to one embodiment of the present specification.

[0024] In the LED display device (100) above, an active area where an image is displayed and an inactive area surrounding the active area may be defined. In the active area, a light-emitting element (e.g., LED) and a driving element (e.g., thin-film transistor) for driving the light-emitting element may be disposed. The inactive area is an area where an image is not displayed, and various wiring and control circuits connected to the elements disposed in the active area may be disposed therein. Referring to FIG. 2, it can be seen that an LED display device according to one embodiment of the present specification is formed with a structure in which various functional elements are stacked on a substrate (110). The substrate (110) is a substrate that supports the components and may be an insulating material. For example, the substrate (110) may be made of glass or resin, etc. Additionally, the substrate (110) may be made of a polymer or plastic. In some embodiments, the substrate (110) may be made of a material having flexibility or foldability.

[0025] The thin film transistor (TFT) may be composed of a gate electrode (101) formed on a substrate (110); a gate insulating layer (112) covering the gate electrode (101); a semiconductor layer (103) formed on the gate insulating layer (112); and a source electrode (105) and a drain electrode (107) on the semiconductor layer (103).

[0026] The gate electrode (101) may be formed of Cr, Mo, Ta, Cu, Ti, Al, or an alloy thereof, and the gate insulating layer (112) may be a single layer made of an inorganic insulating material such as SiOx or SiNx, or a plurality of layers made of SiOx and SiNx.

[0027] The semiconductor layer (103) may be composed of an amorphous semiconductor such as amorphous silicon, or an oxide semiconductor such as IGZO (Indium Gallium Zinc Oxide), TiO2, ZnO, WO3, SnO2. Of course, the semiconductor layer of the thin-film transistor is not limited to a specific material, but any type of semiconductor material currently used in thin-film transistors can be used.

[0028] The source electrode (105) and drain electrode (107) may be made of a metal such as Cr, Mo, Ta, Cu, Ti, Al, etc. or an alloy thereof. At this time, the drain electrode (107) acts as a first electrode that applies a signal to the LED.

[0029] Meanwhile, although the illustrated thin-film transistor (TFT) is a bottom-gate type thin-film transistor, thin-film transistors of other structures, such as a top-gate type thin-film transistor, can also be applied as embodiments of the present invention.

[0030] A second electrode (109) is formed on the gate insulating layer (112) of the display area. At this time, the second electrode (109) may be formed from Cr, Mo, Ta, Cu, Ti, Al, or an alloy thereof, and may be formed by the same process as the drain electrode of the thin-film transistor.

[0031] A first insulating layer (114) is formed over the source electrode (105), drain electrode (107), and second electrode (109), and an LED (140) is placed on the first insulating layer (114). In the embodiment of FIG. 2, a portion of the first insulating layer (114) is removed and an LED (140) is placed in that area, but the first insulating layer (114) may not be removed. The first insulating layer (114) may be composed of an organic layer such as photoacrylic, may be composed of an inorganic layer / organic layer, or may be composed of an inorganic layer / organic layer / inorganic layer.

[0032] A second insulating layer (116) is positioned on the first insulating layer (114). At this time, the second insulating layer (116) may be composed of an organic layer such as photoacrylic, may be composed of an inorganic layer / organic layer, or may be composed of an inorganic layer / organic layer / inorganic layer, and covers the upper region of the LED (140).

[0033] In the first insulating layer (114) and the second insulating layer (116) above the thin film transistor (TFT) and the second electrode (119), a first contact hole (114a) and a second contact hole (114b) are formed, respectively, so that the drain electrode (107) and the second electrode (119) of the thin film transistor (TFT) are each exposed to the outside. Additionally, in the second insulating layer (116) above the p-type electrode (141) and the n-type electrode (143) of the LED (140), a third contact hole (116a) and a fourth contact hole (116b) are each formed, so that the p-type electrode (141) and the n-type electrode (143) are each exposed to the outside.

[0034] On the upper part of the second insulating layer (116), a first connecting electrode (117a) and a second connecting electrode (117b) composed of a transparent metal oxide such as ITO, IGZO, or IGO are formed, and the drain electrode (107) of the thin film transistor (TFT) and the p-type electrode (141) of the LED (140) are electrically connected to the first connecting electrode (117a) through the first contact hole (114a) and the third contact hole (116a), and the second electrode (109) and the n-type electrode (143) of the LED (140) are electrically connected to the second connecting electrode (117b) through the second contact hole (114b) and the fourth contact hole (116b).

[0035] On the upper surface of the substrate (110), a buffer layer (118) made of an inorganic material and / or an organic material can cover and protect the LED (140).

[0036] FIG. 3 is a diagram showing the structure of an LED according to one embodiment of the present specification.

[0037] The above LED (140) may be a micro LED with a size of 10 to 100 μm. The LED (140) comprises an undoped GaN layer (144), an n-type GaN layer (145) disposed on the GaN layer (144), an active layer (146) having a Multi-Quantum-Well (MQW) structure disposed on the n-type GaN layer (145), a p-type GaN layer (147) disposed on the active layer (145), an ohmic contact layer (148) formed of a transparent conductive material and disposed on the p-type GaN layer (147), a p-type electrode (141) in contact with a portion of the ohmic contact layer (148), and an n-type electrode (143) in contact with a portion of the n-type GaN layer (145) exposed by etching a portion of the active layer (146), the p-type GaN layer (147), and the ohmic contact layer (148).

[0038] The above n-type GaN layer (145) is a layer for supplying electrons to the active layer (146) and is formed by doping an n-type impurity, such as Si, into the GaN semiconductor layer.

[0039] The active layer (146) is a layer in which injected electrons and holes combine to emit light. The multiple quantum well structure of the active layer (146) has a plurality of barrier layers and well layers arranged alternately, and the well layers may be composed of InGaN layers and the barrier layers may be composed of GaN, but is not limited thereto.

[0040] The above p-type GaN layer (147) is a layer that injects holes into the active layer (146), and is formed by doping the GaN semiconductor layer with p-type impurities such as Mg, Zn, and Be.

[0041] The above ohmic contact layer (148) is intended to make ohmic contact between the p-type GaN layer (147) and the p-type electrode (141), and a transparent metal oxide such as ITO (Indium Tin Oxide), IGZO (Indium Galium Zinc Oxide), or IZO (Indium Zinc Oxide) may be used.

[0042] The above p-type electrode (141) and n-type electrode (143) may be composed of a single layer or multiple layers made of at least one metal or alloy thereof among Ni, Au, Pt, Ti, Al, and Cr.

[0043] When voltage is applied to the p-type electrode (141) and the n-type electrode (143) in an LED (140) of this structure, electrons and holes are injected from the n-type GaN layer (145) and the p-type GaN layer (147), respectively, into the active layer (145), excitons are generated within the active layer (146), and as these excitons decay, light corresponding to the energy difference between the LUMO (Lowest Unoccupied Molecular Orbital) and HOMO (Highest Occupied Molecular Orbital) of the light-emitting layer is generated and emitted outward. At this time, the wavelength of the light emitted from the LED (140) can be controlled by adjusting the thickness of the barrier layer of the multi-quantum well structure of the active layer (146).

[0044] The above LED (140) is fabricated by forming a buffer layer on a substrate and growing a GaN thin film on the buffer layer. At this time, sapphire, silicon (Si), GaN, silicon carbide (SiC), gallium arsenide (GaAs), zinc oxide (ZnO), etc. can be used as substrates for growing the GaN thin film.

[0045] The above buffer layer is intended to prevent quality degradation caused by lattice mismatch when an n-GaN layer (120), which is an epi layer, is directly grown on a substrate when the substrate for GaN thin film growth is made of a material other than a GaN substrate, and AlN or GaN, etc. may be used.

[0046] The n-type GaN layer (145) can be formed by growing an undoped GaN layer (144) and then doping an n-type impurity, such as Si, onto the undoped thin film. Additionally, the p-type GaN layer (147) can be formed by growing an undoped GaN thin film and then doping it with a p-type impurity, such as Mg, Zn, or Be.

[0047] The LED (140) produced by the above process is transferred to a substrate (110) as shown in FIG. 2 and used in a display device. At this time, the process of transferring the LED (140) is also called transfer. Representative examples of the above transfer process are direct transfer and print transfer.

[0048] The above direct transfer is a technique for directly bonding a material or thin film to be transferred to a target substrate. As an example of the above direct transfer, a method may be used in which p-type GaN is separated into several micrometers by an etching process and then directly bonded to a substrate on which a switching device is formed.

[0049] Meanwhile, print transfer is a technology that utilizes intermediate media such as electrostatic stamps or bonding stamps. Regarding the transfer equipment used in the above print transfer method, it is known that i) an electrostatic head and ii) an elastomer stamp are used as pickup devices to pick up LEDs. i) applies voltage to the head portion to generate adhesion with the LED due to an electrostatic phenomenon. This method has the advantage of being able to selectively transfer a desired area or a single element, but a problem may arise where the LED is damaged by the voltage applied to the head during electrostatic induction. ii) is a method that uses an elastic polymer material as a transfer head to transfer the LED to a desired substrate. Although this method does not have the problem of LED damage compared to the electrostatic head method, it has the disadvantages of a slow transfer speed and difficulty in controlling the pickup strength and / or duration because it is based on Van der Waals forces, which are weaker than other bonding forces.

[0050] The inventors of this specification recognized the advantages and disadvantages of the LED transfer methods described above and devised a solution capable of resolving the problems of LED damage and transfer stability.

[0051] FIGS. 4a and 4b are simplified drawings of an LED transfer device according to one embodiment of the present specification.

[0052] The LED transfer device for transferring the aforementioned LED from one substrate to another may be composed of several functional units, and below, the LED transfer device will be described with a focus on a pickup unit that picks up the LED (140) from the substrate and lowers it onto another substrate. The LED transfer device may be equipped with a control unit to control several functional units, including the pickup unit. The substrate (10) shown in FIG. 4a is a substrate before the LED transfer is completed, and may be a growth substrate where the LED (140) is generated, or a transport substrate at the stage before the LED is finally mounted.

[0053] The above pickup unit may include a head (230) configured to lift an LED (140) on one substrate and lower the LED (140) onto another substrate; a transport arm (220) for moving the head (230); and a cover (250) configured to provide a specific space for accommodating the head (230) and the one substrate or the other substrate. Meanwhile, the control unit controls the LED (140) to be attached to or detached from the head (230) by adjusting the air pressure in the sealed space provided by the cover (250).

[0054] Additionally, the LED transfer device may further include a support (210) configured to place the one substrate or the other substrate on its upper surface and to provide a sealed space together with the cover (250). In another embodiment, the support (210) may be configured separately from the LED transfer device.

[0055] The head (230) may be configured to include a plate (231) connected to the transport arm (220); and a stamp (232) having one side bonded to the plate (231) and the other side provided with a fine groove to contact the LED (140).

[0056] An example of the stamp (232) is illustrated in FIG. 4b. The stamp (232) may be made of an elastomer having a certain elasticity so as not to cause impact when in contact with the LED. For example, the stamp (232) may be made of rubber, a polymeric organosilicon such as PDMS, etc. The stamp (232) has one or more microgrooves on one surface. The microgrooves may be in the shape of a cylinder, a cone, or a polygonal column, and several of them are placed on the upper surface of the LED (140). Accordingly, the LED (140) can be held or released depending on the pressure difference between the inside of the microgrooves and the outside. At this time, the stamp (232) has enough elasticity (about 10) so that it does not slide on the upper surface of the LED (140) when in contact. -3 to 10 -1 It is appropriate to have a shear elastic modulus of GPa. The microgrooves may have a diameter of 10 micrometers (μm) or less and may be formed to occupy 40 to 80% of the total stamp area. In addition, the depth of the microgrooves may be 2 to 5 times the diameter.

[0057] Although the plate (231) and the stamp (232) are depicted separately in the drawing, the two parts may be a single integrated unit. That is, a stamp having a fine groove on one surface may be directly connected to the transport arm (220).

[0058] The above transport arm (220) is connected to the head and moves the head (230) three-dimensionally under the control of the control unit. The cover (250) can be seated on the upper part of the support (210) to form a predetermined sealed chamber. The sealed chamber formed in this way is very small, so 10 -1 It is easy to create a vacuum level below atm.

[0059] The control unit is configured to raise the pressure of the sealed space to any one of atmospheric pressure, a first pressure lower than atmospheric pressure, and a second pressure lower than the first pressure. Here, the first pressure is 10 -1 It is atm, and the above second atmosphere is 10 -2 It may be atm. In this case, to change the air pressure, a passage for air inlet or outlet may be provided in the cover (250) and / or the support (210). Additionally, equipment such as a known vacuum pump may be used to regulate the pressure inside the sealed space.

[0060] FIGS. 5a to 5i are drawings illustrating an LED transfer method according to one embodiment of the present specification.

[0061] According to one embodiment of the present specification, a method for transferring a light-emitting diode (LED) on one substrate to another substrate can be performed by an LED transfer device described in FIG. 4a and 4b. The method can be performed as follows.

[0062] First, one side of a head (230) having a microgroove is positioned on the upper surface of an LED (140) on a substrate (10). At this time, the head (230) is provided with an elastic stamp made of a polymer material on one side, and the elastic stamp has at least one of the microgrooves. The head (230) can make contact only with some of the LEDs to be picked up among all the LEDs on the substrate (10). This is to match the LED arrangement conditions required on the substrate to be transferred. The above process can be carried out at a reference pressure (e.g., 1 atm).

[0063] Next, as shown in FIG. 5a, a first sealed space including the substrate (10) and the head (230) is provided, and the pressure inside the first sealed space is lowered to a first pressure (L1) lower than the reference pressure. The first pressure (L1) is approximately 10 -1 It may be an atm. The first sealed space may be formed by the cover (250) being in close contact with the support (210). Then, as shown in FIG. 5b, the head (230) is brought into contact with the upper surface of the LED (140) while the inside of the sealed space is at the first atmospheric pressure (L1).

[0064] Next, as shown in FIG. 5c, the pressure inside the first sealed space is raised to the reference pressure (L0). At this time, the inside of the micro-groove is maintained at the first pressure (L1). Then, as shown in FIG. 5b, the head (230) is lifted to separate the LED (140) from the substrate (10). At this time, the LED (140) is separated from the substrate (10) by the vacuum inside the micro-groove and lifted together with the head (230).

[0065] Next, as shown in FIG. 5e, the separated LED (140) and the head (230) holding the LED (140) are positioned on the upper part of another substrate (20). Here, the other substrate (20) may be a final substrate or an intermediate transport substrate. The process may be carried out at a reference pressure (L0). At this time, the inside of the microgroove is still maintained at the first pressure (L1).

[0066] Next, as shown in FIG. 5f, the head (230) is lowered to bring the LED (140) into contact with the other substrate (20). Before or after the contact, a second sealed space is provided that includes the head (230) holding the other substrate (20) and the LED (140). Then, as shown in FIG. 5g, the pressure inside the second sealed space is lowered to a second pressure (L2) that is lower than the first pressure (L1). The second pressure (L2) is approximately 10 -2 It may be atm. Due to such pressure fluctuations, the vacuum adhesion force caused by the micro-grooves is lost, and the attachment between the head (230) and the LED (140) is released.

[0067] Next, as shown in FIG. 5h, the head (230) is lifted, and as shown in FIG. 5i, the pressure inside the second sealed space is raised to the reference pressure (L0). Then, when the cover (250) and the head (230) are lifted, the transfer process is completed.

[0068] Compared to conventional transfer methods, the LED transfer device and transfer method described above reduce LED damage and can shorten the transfer speed from minutes to seconds. This can lead to increased productivity of LED display devices.

[0069] Although the embodiments of this specification have been described in detail with reference to the attached drawings, this specification is not necessarily limited to these embodiments and may be modified in various ways within the scope of the technical concept. Accordingly, the embodiments disclosed in this specification are intended to explain, not limit, the technical concept of the invention, and the scope of the technical concept of the invention is not limited by these embodiments. The features of each of the various embodiments of the invention may be combined or combined with one another, either partially or wholly, and may be technically interconnected and operated in various ways by those skilled in the art. Furthermore, each embodiment may be implemented independently of one another or together in an associated relationship. The scope of protection of the invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the invention.

Claims

Claim 1 A display device comprising a plurality of display panels arranged in a tile shape, wherein the display panels include: a substrate; a plurality of thin-film transistors disposed on the substrate; a first insulating layer disposed on the plurality of thin-film transistors; a micro LED disposed in an area where a portion of the first insulating layer is removed; and a second insulating layer disposed on the micro LED and the first insulating layer, wherein a second electrode is disposed on the same layer as a first electrode which is the drain electrode of the thin-film transistor, and the first insulating layer is disposed on the first electrode and the second electrode, wherein the micro LED is separated from a substrate when rising from a first pressure lower than the reference pressure to the reference pressure in a first sealed space, and is attached to an area where a portion of the first insulating layer is removed on the substrate when rising from a second pressure lower than the first pressure to the reference pressure in a second sealed space, and in the area where a portion of the first insulating layer is removed, the bottom surface of the micro LED is in direct contact with the upper surface of the first insulating layer. Claim 2 A display device according to claim 1, wherein the thin-film transistor comprises a source electrode and a drain electrode, the drain electrode acts as the first electrode for applying a signal to the micro LED, the first electrode and the second electrode are formed on a gate insulating layer, and the first insulating layer is disposed on the source electrode, the drain electrode, and the second electrode. Claim 3 A display device according to claim 1, wherein a first connecting electrode and a second connecting electrode are disposed on the upper portion of the second insulating layer, and a buffer layer is disposed on the second insulating layer, the first connecting electrode and the second connecting electrode. Claim 4 A display device according to claim 3, wherein a first contact hole and a second contact hole are formed in the first insulating layer and the second insulating layer, respectively, so that the drain electrode and the second electrode are each exposed to the outside, and the second insulating layer is disposed on top of the p-type electrode and the n-type electrode of the micro LED, and the p-type electrode and the n-type electrode are exposed to the outside through the third contact hole and the fourth contact hole formed, respectively. Claim 5 A display device according to claim 4, wherein the drain electrode and the p-type electrode are electrically connected to the first connecting electrode through the first contact hole and the third contact hole, and the second electrode and the n-type electrode are electrically connected to the second connecting electrode through the second contact hole and the fourth contact hole. Claim 6 delete Claim 7 delete Claim 8 In claim 4, the display device wherein the third contact hole and the fourth contact hole are configured in a circular or square shape. Claim 9 In claim 1, the substrate is a display device composed of a transparent material. Claim 10 In claim 1, the substrate is a flexible substrate, and the display device. Claim 11 In claim 1, the micro LED is connected to a driving unit through a gate line and a data line, forming a display device. Claim 12 A display device according to claim 1, wherein the first insulating layer and the second insulating layer each comprise one or more organic layers or one or more inorganic layers. Claim 13 In claim 1, the interface between the first insulating layer and the second insulating layer is a display device located above the lower surface of the micro LED. Claim 14 In claim 1, the micro LED is a display device having a size of 10-100㎛.

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