KR101628345B1 - Method for manufacturing nano-scale LED electrode assembly - Google Patents

Abstract

[0001] The present invention relates to a method of manufacturing a very small LED electrode assembly, and more particularly, to a method of manufacturing a very small LED electrode assembly, in which a very small LED element can be concentrated and dispersed in an electrode line on which a very small LED element is mounted, To a method of manufacturing an ultra-small LED electrode assembly that can be connected.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a miniature LED electrode assembly,

The present invention relates to a method of manufacturing an ultra-small LED electrode assembly, and more particularly, to a method of manufacturing an ultra-small LED electrode assembly which is capable of concentrating and dispersing an ultra-small LED element in an intended electrode region, And at the same time to a miniature LED electrode assembly capable of connecting a miniature LED device of a nano unit to a miniature electrode without fail.

In 1992, Nakamura of Nichia Corporation of Japan succeeded in fusing high quality monocrystalline GaN nitride semiconductors by applying a low-temperature GaN compound layer, which has been actively developed. An LED is a semiconductor having a structure in which an n-type semiconductor crystal in which a plurality of carriers are electrons and a p-type semiconductor crystal in which a plurality of carriers are holes are bonded to each other using the characteristics of compound semiconductors, And is converted into light to be displayed.

These LED semiconductors have a very low energy consumption due to high photoconversion efficiency, have a semi-permanent and environmentally friendly life, and are called the revolution of light as a green material. In recent years, the development of compound semiconductor technology has led to the development of high-brightness red, orange, green, blue, and white LEDs that are used in many fields, such as traffic lights, cell phones, automotive headlights, outdoor display panels, LCD backlight units And it has been actively researched at home and abroad. In particular, GaN compound semiconductors having a wide band gap are materials used for manufacturing LED semiconductors emitting green, blue, and ultraviolet light, and a white LED device can be manufactured using a blue LED device. .

In addition, the utilization of various fields of LED semiconductors and researches on them have necessitated high output LED semiconductors and it has become very important to improve the efficiency of LED semiconductors. However, there are various difficulties in fabricating a blue LED device with high efficiency and high output. The difficulty in improving the efficiency of the blue LED device is due to the difficulty in the manufacturing process and the high refractive index of the GaN-based semiconductor of the manufactured blue LED and the atmosphere. First, the difficulty in the manufacturing process is that it is difficult to have a substrate having the same lattice constant as that of the GaN-based semiconductor. The GaN epitaxial layer formed on the substrate has many defects when the lattice constants are largely inconsistent with the substrate, resulting in low efficiency and low performance.

Next, light emitted from the active layer region of the LED does not escape to the outside due to the high refractive index of the GaN-based semiconductor of the manufactured blue LED and the atmosphere, and is totally reflected in the LED. Thus, the total reflection light is reabsorbed from the inside, resulting in a problem that the efficiency of the LED is deteriorated. This efficiency is called the light extraction efficiency of an LED device, and many studies have been conducted to solve this problem.

On the other hand, in order to utilize the LED element in illumination, display, etc., an LED element and an electrode capable of applying power to the element are required, and the application purpose, the space occupied by the electrode, The placement of the two electrodes has been studied extensively.

A study on the arrangement of the LED element and the electrode can be classified into growing the LED element on the electrode and separately growing the LED element separately and placing it on the electrode.

First, research on growing an LED element on an electrode has been carried out in such a manner that a lower electrode is thinned on a substrate, an n-type semiconductor layer, an active layer, a p-type semiconductor layer and an upper electrode are sequentially stacked on the substrate, There is a bottom-up method in which an LED element and an electrode are simultaneously formed and arranged in a series of manufacturing processes through a method of laminating an upper electrode after etching the layers.

Next, a method in which the LED elements are independently grown separately and then disposed on the electrodes is a method of disposing each LED element independently grown on a patterned electrode by a separate process.

The former method has a problem that crystallization of highly crystalline / high-efficiency thin film and LED element is very difficult, and the latter method has a problem that the light extraction efficiency is lowered and the luminous efficiency is lowered.

In the case of the latter method, a three-dimensional LED element can be connected to the electrode by a conventional LED element. However, when the LED element is very small in size of nano unit, it is very difficult to stand upright on the electrode. Korean Patent Application No. 2011-0040174 by the inventor of the present application has constructed a miniature LED device with a coupling linker for facilitating bonding with an electrode in order to connect the miniature LED device of the nano unit size upright three dimensionally to the electrode, There has been a problem that it is very difficult to mount the ultra-small LED element in three-dimensional upright position when the LED is mounted on the ultra-small electrode.

Further, it is very difficult to arrange the LED devices independently in two different electrode lines when the sizes of the LED devices are very small in terms of nano unit, and it is very difficult to arrange the ultra-small LED devices in a solution state Even if the LED elements are arranged in a very small electrode line by self-alignment, it is very difficult to arrange the ultra-small LED elements in a desired mounting range, such that the ultra-small LED elements are stacked and arranged in a specific portion of the electrode line, There is a problem.

Furthermore, there is a problem that a desired electrode assembly is not realized due to frequent defects due to short circuit in electrical connection between the electrode line and the micro LED.

Korean Patent Application No. 2010-0042321 discloses a structure and a manufacturing method of an address electrode line for an LED module. In the case of the above application, the lower electrode is thinned on the substrate, the insulating layer and the upper electrode are stacked on the lower electrode in order, and then the electrode chip is etched to mount the LED chip on the upper electrode. However, when the mounted LED chip has a size of nano unit, there is a problem that it is very difficult to mount the three-dimensional LED chip on the upper electrode accurately, and it is difficult to connect the mounted LED chip and the lower electrode after mounting There is a problem. In addition, since the n-type and p-type semiconductor layers of the LED chip are arranged at the upper and lower sides of the substrate, the light generated in the active layer region is blocked by the electrodes of the LED chip, There is a problem that extraction efficiency is low.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a light emitting diode (LED) And a method of manufacturing the miniature LED electrode assembly.

In addition, when the ultra-small LED element is put in a solution state, the problem that the ultra-small LED elements in the electrode line region are gathered and arranged only in a specific portion, or the element is spread out to the outside and can not be mounted or mounted can be solved, The present invention also provides a method of fabricating an LED electrode assembly.

According to an aspect of the present invention, there is provided a plasma display panel comprising: (1) an electrode line including a base substrate, a first electrode formed on the base substrate and a second electrode formed on the same plane as the first electrode, A step of injecting a very small LED element; And (2) applying solvent to the electrode lines to simultaneously connect the plurality of ultra-small LED elements to the first and second electrodes, and applying power to the electrode lines to self-align the plurality of ultra-small LED elements; And a method of manufacturing the ultra-small LED electrode assembly.

According to a preferred embodiment of the present invention, the first electrode and the second electrode of the step (1) may be spaced apart by any one of a spiral arrangement and an interdigitated arrangement.

According to another preferred embodiment of the present invention, the ultra-small LED element

A first conductive semiconductor layer; An active layer formed on the first conductive semiconductor layer; And a second conductive semiconductor layer formed on the active layer.

According to another preferred embodiment of the present invention, the ultra miniature LED device comprises an insulating film covering at least an entire outer surface of an active layer portion to prevent a short circuit caused by contact between an active layer and an electrode line of an ultra- .

According to another preferred embodiment of the present invention, the ultra miniature LED device may include a hydrophobic film coated on the outer surface of the insulation film of the ultra-small LED device to prevent aggregation between the devices.

According to another preferred embodiment of the present invention, the ultra miniature LED device may include a first electrode layer formed under the first conductive semiconductor layer and a second electrode layer formed over the second conductive semiconductor layer.

According to another preferred embodiment of the present invention, the first electrode layer and the second electrode layer of the ultra miniature LED device may not be coated with an insulating coating.

According to another preferred embodiment of the present invention, the length of the ultra-small LED device is 100 nm to 10 μm, and the aspect ratio may be 1.2 to 100.

According to another preferred embodiment of the present invention, the width X of the first electrode, the width Y of the second electrode, the distance Z between the first electrode and the second electrode adjacent to the first electrode Z ) And the length (H) of the ultra-small LED element can satisfy the following relational expression (1).

[Relation 1]

X, Y and Z are 100 nm < X &lt; / = 10 mu m, 100 nm &lt;

According to another preferred embodiment of the present invention, the step (1) comprises the steps of: 1-1) forming a first electrode on the base substrate, a first electrode formed on the base substrate, and a second electrode formed on the same plane as the first electrode, &Lt; / RTI &gt; 1-2) forming an insulating barrier surrounding the electrode line region on which the micro LED device is mounted on the base substrate; And 1-3) applying a plurality of ultra-small LED elements to the electrode line region surrounded by the insulating barrier ribs.

According to another preferred embodiment of the present invention, the voltage of the power source applied in the step (2) may be 0.1 V to 1000 V, and the frequency may be 10 Hz to 100 GHz.

According to another preferred embodiment of the present invention, in the step (2), the number of the ultra miniature LED elements simultaneously connected to the first electrode and the second electrode is such that the area of the electrode line on which the ultra-small LED element is mounted is 100 × 100 μm ² Can be from 2 to 100,000 per molecule.

According to another preferred embodiment of the present invention, the width X of the first electrode, the width Y of the second electrode, the distance Z between the first electrode and the second electrode adjacent to the first electrode Z ) And the length (H) of the ultra-small LED element can satisfy the following relational expression (1).

[Relation 1]

X, Y and Z satisfy 100nm &lt; X &lt; / = 10 mu m, 100nm &lt;

According to another preferred embodiment of the present invention, (3) forming a metal ohmic layer on a connection portion between the electrode and any one or more of the first electrode and the second electrode and the micro LED device.

Hereinafter, terms used in the present invention will be defined.

In describing an embodiment in accordance with the present invention, it is to be understood that each layer, region, pattern or structure may be referred to as being "on", "over", " The terms "on", "upper", "upper", "under", "lower", "lower" And "indirectly".

&Quot; First electrode &quot; and &quot; second electrode &quot; in the description of the embodiment according to the present invention may further be included according to the method of arranging the electrode on the base substrate together with the electrode region or the region where the ultra- To the electrode region. However, the miniature LED electrode assembly of the present invention means an electrode region where the ultra-miniaturized LED can be substantially mounted.

In the description of the embodiment according to the present invention, the term "unit electrode" means an array region in which two electrodes capable of being independently driven by arranging the ultra-small LED elements are arranged, and the unit electrode area means an area of the array region.

In the description of the embodiment according to the present invention, &quot; connection &quot; means that the ultra miniature LED device is mounted on two different electrodes (for example, the first electrode and the second electrode). The term &quot; electrically connected &quot; means a state in which a very small LED element emits light when a very small LED element is mounted on two different electrodes and a power source is applied to an electrode line.

In the method of manufacturing the LED electrode assembly of the present invention, firstly, the miniature LED device of the nano unit size manufactured independently is connected to the two different small electrodes without defects such as electric short, It is difficult to erect the miniature LED element when it is coupled to the electrode and it is difficult to combine the miniature LED element with the miniature different electrodes in a one-to-one correspondence.

In addition, due to the relative positional relationship between the structure of the ultra-small LED element connected to the electrode and the substrate, that is, due to the arrangement of the ultra-small LED elements arranged horizontally on the substrate in the longitudinal direction of the ultra-small LED element, The light extraction efficiency of the ultra miniature LED electrode assembly can be greatly improved and the number of ultra small LED elements connected to different electrodes can be adjusted so that the desired light amount can be easily obtained.

Furthermore, since the ultra-small LED element is erected and does not three-dimensionally couple with the upper and lower electrodes, it is easy to self-assemble the ultra-small LED element between the other two electrodes, so that the ultra-small LED can be arranged in a driveable state The area mass production process is possible and the original function of the miniature LED electrode assembly can be maintained by connecting a plurality of LED elements to the electrodes in preparation for defective LED elements.

In addition, when the ultra-small LED element is put in a solution state, the problem that the ultra-small LED elements in the electrode line region are gathered to only a specific portion or the element is spread out to the outside can not be mounted or mounted can be solved, By self-aligning the LED element, it is possible to arrange the ultra-small LED element concentrating on the target electrode line region, and the amount of light obtained can be remarkably increased.

1 is a perspective view illustrating a step of fabricating a micro LED electrode assembly according to a preferred embodiment of the present invention.
2 is a perspective view illustrating a manufacturing process of an electrode line according to a preferred embodiment of the present invention.
3 is a perspective view of an electrode line including a first electrode and a second electrode formed on a base substrate according to a preferred embodiment of the present invention.
4 is a plan view of an electrode line including a first electrode and a second electrode formed on a base substrate according to a preferred embodiment of the present invention.
5 is a perspective view of an electrode line including a first electrode and a second electrode formed on a base substrate according to a preferred embodiment of the present invention.
6 is a perspective view of an ultra-small LED according to a preferred embodiment of the present invention.
7 is a vertical sectional view of a conventional miniature LED electrode assembly.
8 is a plan view and a vertical cross-sectional view of an ultra-small LED device connected to a first electrode and a second electrode according to a preferred embodiment of the present invention.
9 is a perspective view illustrating a manufacturing process of forming an insulating partition on a base substrate according to a preferred embodiment of the present invention.
10 is a perspective view illustrating a manufacturing process of a micro LED electrode assembly according to a preferred embodiment of the present invention.
11 is a perspective view and a partial enlarged view of a micro LED electrode assembly according to a preferred embodiment of the present invention.
12 is a SEM photograph of a micro LED electrode assembly according to a preferred embodiment of the present invention and a blue electroluminescent image of an ultra-small LED.
13 is a blue electroluminescence spectrum of a micro LED electrode assembly according to a preferred embodiment of the present invention.
FIG. 14 is a TEM photograph of an ultra-small LED element included in a preferred embodiment of the present invention.
15 is an optical micrograph of a 1500-fold magnification of a micro LED electrode assembly manufactured according to a preferred embodiment of the present invention.
16 is an optical microscope image magnified 1500 times with respect to the micro LED electrode assembly manufactured by the comparative example of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

As described above, the conventional bottom-up method has a problem that crystallization of an LED device having a high crystallinity / high efficiency thin film and an n-type / quantum well / p-type lamination structure is very difficult, A method of disposing each LED element individually on the patterned electrode is as follows. When the LED element is a general LED element, the three-dimensional LED element can be erected upright and connected to the electrode. However, when the LED element is an ultra- There is a problem that it is very difficult to stand upright on the electrode. In addition, when the size of the LED element is very small in terms of nano unit, it is very difficult to arrange and arrange the ultra-small LED elements in two small and different electrodes in a desired area, and to connect the LED element without defects such as electrical shorts. Furthermore, when the ultra miniature LED device is put in a solution state in a solution state and is self-aligned, the ultra-small LED elements can be arranged only at the outer periphery of the electrode area or can be arranged in a bundle, There is a problem in that it is difficult to even mount the circuit board.

(1) a step of injecting a plurality of ultra-small LED elements into an electrode line including a base substrate, a first electrode formed on the base substrate and a second electrode formed on the same plane as the first electrode, ; And (2) applying solvent to the electrode lines to simultaneously connect the plurality of ultra-small LED elements to the first and second electrodes, and applying power to the electrode lines to self-align the plurality of ultra-small LED elements; The present invention has been made to solve the above-mentioned problems by providing a method for manufacturing an ultra-small LED electrode assembly.

Accordingly, when a conventional micro LED device is erected and bonded to an electrode in a three-dimensional shape, the micro LED device can not be erected uprightly, and it is difficult to combine the micro LED devices with one another in a one-to- . In addition, when a very small LED element is put in a solution state, very small LED elements in an electrode line area are gathered to be located only in a specific part, or the element floats in a solution and spreads to the outside of an electrode line, By miniaturizing the micro-sized LED element in the element mounting region, the micro-sized LED element can be arranged in the intended electrode line region and the micro-sized LED element can be connected to the electrode without defects. Further, since the amount of photons emitted from the active layer to the atmosphere increases due to the directionality of the ultra-small LED device connected to the electrode, the light extraction efficiency of the ultra-small LED electrode assembly can be greatly improved.

In the step (1) according to the present invention, a plurality of ultra-small LED elements are charged into an electrode line including a base substrate, a first electrode formed on the base substrate and a second electrode formed on the same plane as the first electrode do.

1 is a perspective view illustrating a step of fabricating a micro LED electrode assembly according to a preferred embodiment of the present invention. Referring to FIG. 1A, a first electrode 110 is formed on a base substrate 100, A second electrode 130 formed on the same plane and spaced apart from the first electrode 110, and an ultra-small LED element 120 inserted into the electrode line including the first electrode 110 and the second electrode 130.

First, a method of manufacturing an electrode line including a first electrode and a second electrode formed on the same plane as the first electrode is described. 2 is a perspective view illustrating a manufacturing process of an electrode line formed on a base substrate according to a preferred embodiment of the present invention. However, the manufacturing process of the electrode line is not limited to the manufacturing process described later.

2A is a base substrate 100 on which electrode lines are formed. The base substrate 100 is preferably made of a material selected from the group consisting of a glass substrate, a quartz substrate, a sapphire substrate, a plastic substrate, and a bendable flexible polymer film Lt; / RTI &gt; More preferably, the base substrate 100 may be a transparent substrate. However, the material of the base substrate 100 is not limited to the above-described type, and any type of material may be used in the case of a base substrate on which an electrode can be formed.

The area of the base substrate 100 is not limited. The area of the first electrode to be formed on the base substrate 100, the area of the second electrode, the size of the micro LED device connected to the first electrode and the second electrode, The number of ultra-small LED elements to be connected, and the like. Preferably, the thickness of the base substrate 100 is 100 탆 to 1 mm, but is not limited thereto.

Then, as shown in FIG. 2B, a photoresist (PR) 101 may be coated on the base substrate 100. The photoresist may be a photoresist commonly used in the art. The method of coating the photoresist on the base substrate 100 may be any one of spin coating, spray coating, and screen printing, and may preferably be spin coating, but the present invention is not limited thereto. And can be carried out by a known method. The thickness of the photoresist 101 to be coated may be 0.1 to 10 탆. However, the thickness of the photoresist 101 to be coated may be changed in consideration of the thickness of the electrode to be deposited on the base substrate.

After the photoresist 101 layer is formed on the base substrate 100 as described above, a first electrode and a second electrode are formed on the same plane, The mask 102 on which the patterns 102a and 102b are drawn can be placed on the photoresist 101 layer as shown in Fig. 2C and the ultraviolet rays can be exposed on the mask 103. [

Thereafter, the exposed photoresist layer is dipped in a conventional photoresist solvent to remove the exposed photoresist layer portion where the electrode line is to be formed as shown in FIG. 2D. The width of the pattern 102a corresponding to the first electrode line corresponding to the electrode line for the micro LED may be 100 nm to 50 mu m and the width of the pattern 102b corresponding to the second electrode line may be 100 nm to 50 mu m However, the present invention is not limited to the above description.

Then, as shown in FIG. 2E, the electrode forming material 103 may be deposited on the portion of the electrode line mask 102 where the photoresist layer is removed. The electrode forming material may be at least one metal selected from the group consisting of aluminum, titanium, indium, gold and silver, or indium tin oxide (ITO), ZnO: Al and CNT-conductive polymer May be any one or more of the transparent materials selected from the group consisting of When the electrode forming materials are two or more kinds, the first electrode may be a structure in which two or more kinds of materials are laminated. More preferably, the first electrode may be an electrode in which a second material is laminated with titanium / gold. However, the first electrode is not limited to the above-described substrate.

The electrode forming material may be at least one metal material selected from the group consisting of aluminum, titanium, indium, gold and silver, indium tin oxide (ITO), ZnO: Al and CNT-conductive polymer The second electrode may be a structure in which two or more kinds of materials are stacked. More preferably, the second electrode may be an electrode in which a two-material material is laminated with titanium / gold. However, the second electrode is not limited to the above-described substrate.

The materials forming the first and second electrodes may be the same or different.

The deposition of the electrode forming material may be performed by any one of a thermal deposition method, an e-beam deposition method, a sputtering deposition method, and a screen printing method, and is preferably a thermal deposition method, but is not limited thereto.

After the electrode forming material 103 is deposited, a photoresist such as acetone, 1-methyl-2-pyrrolidone (NMP), or dimethyl sulfoxide (DMSO) When the photoresist layer 101 coated on the base substrate 100 is removed using a removing agent, electrode lines 103 (110 in FIG. 1), 103 (130 in FIG. 1) deposited on the base substrate 100, Can be prepared.

In the electrode line according to the present invention manufactured through the above-described method, the unit electrode area, that is, the area of the arrangement region in which the two electrodes capable of independently driving the micro-LED devices are arranged is preferably 1 to ² cm ² , and more preferably 10 μm ² to 100 mm ² , but the area of the unit electrode is not limited to the above-mentioned area. In addition, the electrode line may include one or a plurality of unit electrodes.

Furthermore, the spacing between the first electrode and the second electrode in the electrode line may be less than or equal to the length of the micro-LED element. Thus, the ultra-small LED element may be laid between the first electrode and the second electrode so as to be sandwiched between the two electrodes or across the two electrodes.

Meanwhile, the electrode line applicable to the present invention is a second electrode formed on the same plane as the first electrode to be described later, and can be applied as long as it can mount the ultra-small LED device. The specific arrangement of the second electrode may vary depending on the purpose.

Specifically, FIG. 3 is a perspective view of an electrode line for a first electrode and a second electrode formed on a base substrate according to a preferred embodiment of the present invention, and a first electrode 213 may be formed on the base substrate 200 . Means that one or more of the first electrode and the second electrode may be formed directly on the base substrate surface or spaced apart from the upper surface of the base substrate.

More specifically, in FIG. 3, the first electrodes 214 and 214 and the second electrodes 233 and 234 are formed directly on the surface of the base substrate 200 while the first and second electrodes 214 and 234 are formed directly on the surface of the base substrate 200, The electrode lines 244 may be arranged alternately and spaced on the same plane.

FIG. 4 is a plan view of an electrode line for a first electrode and a second electrode formed on a base substrate according to a preferred embodiment of the present invention, in which the first electrodes 212 and 215 and the second electrodes 232 and 235 are both a base The first electrode 215 and the second electrode 235 are formed directly on the surface of the substrate 201 so that the electrode line 245 can be formed on the same plane.

When the electrode lines are alternately arranged or spirally arranged as described above, the miniaturized LEDs included in the base substrates 200 and 201 having a limited area can be arranged at one time to increase the driving area of the unit electrodes that can be independently driven So that the number of very small LEDs mounted on the unit electrode can be increased. This increases the intensity of LED light emission in a unit area, and thus can be utilized for various photoelectric devices requiring high brightness per unit area.

3 and 4 are preferred embodiments. However, the present invention is not limited thereto, and the two electrodes can be variously modified by arranging all imaginable structures having a predetermined interval.

In addition, according to another preferred embodiment of the present invention, the second electrode may be spaced apart from the upper portion of the base substrate, unlike the electrode line according to the preferred embodiment of the present invention shown in FIG.

5 is a perspective view of an electrode line for a first electrode and a second electrode formed on a base substrate according to a preferred embodiment of the present invention, in which a first electrode 211 is formed directly on a surface of a base substrate 202 The first and second electrodes 231 and 236 are spaced apart from the upper surface of the base substrate 202. The first electrode 216 is connected to the first electrode 211 through a connection electrode, And the first electrode 216 and the second electrode 236 are alternately arranged on the same plane to form a spaced apart electrode line 246 .

Hereinafter, the first electrode and the second electrode are alternately disposed on the same plane. However, the first electrode and the second electrode may be formed directly on the surface of the base substrate or spaced apart from the surface of the base substrate. If at least one of the first electrode and the second electrode is formed apart from the surface of the base substrate All portions of the first electrode and all portions of the second electrode may not be coplanar. In this case, however, the first electrode and the second electrode included in the region where the ultra-miniaturized LED can be substantially mounted can be located on the same plane.

Next, a very small LED element (120 in Fig. 1A) will be described.

The ultra-small LED device that can be used in the present invention can be used without limitation as long as it is an ultra-small LED device generally used for illumination or display. Preferably, the length of the ultra-small LED device in step (1) And even more preferably from 500 nm to 5 占 퐉. If the length of the ultra-small LED element is less than 100 nm, it is difficult to manufacture a highly efficient LED element. If the length is more than 10 탆, the efficiency of the LED element may be reduced. The shape of the ultra-small LED element may be various shapes such as a columnar shape or a rectangular parallelepiped shape, and may be a cylindrical shape, but is not limited thereto.

Hereinafter, in the description of the ultra-small LED device, the terms "upper", "lower", "upper", "lower", "upper" .

According to a preferred embodiment of the present invention, the ultra miniature LED device includes a first conductive semiconductor layer; An active layer formed on the first conductive semiconductor layer; And a second conductive semiconductor layer formed on the active layer.

Specifically, FIG. 6 is a perspective view illustrating an exemplary embodiment of a micro-LED element included in the present invention, and includes a first conductive semiconductor layer 21, an active layer 22 formed on the first conductive semiconductor layer 21, And a second conductive semiconductor layer 23 formed on the second conductive semiconductor layer 22.

First, the first conductive semiconductor layer 21 will be described. The first conductive semiconductor layer 21 may include, for example, an n-type semiconductor layer. In the case where the ultra-small LED elements one blue light emitting device, the n-type semiconductor layer is _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0 ≤y≤1, 0≤x + y≤1) A semiconductor material having a composition formula of InAlGaN, GaN, AlGaN, InGaN, AlN, InN or the like may be selected and doped with a first conductive dopant such as Si, Ge, Sn or the like. The thickness of the first conductive semiconductor layer 21 may be 500 nm to 5 탆, but is not limited thereto. Since the light emission of the ultra-small LED is not limited to blue, there is no limit to the use of other kinds of III-V semiconductor materials as the n-type semiconductor layer when the emission colors are different.

Next, the active layer 22 formed on the first conductive semiconductor layer 21 will be described.

When the ultra-small LED device is a blue light emitting device, the active layer 22 may be formed on the first conductive semiconductor layer 21 and may have a single or multiple quantum well structure. A cladding layer (not shown) doped with a conductive dopant may be formed on and / or below the active layer 22, and the cladding layer doped with the conductive dopant may be formed of an AlGaN layer or an InAlGaN layer. In addition, materials such as AlGaN and AlInGaN may be used as the active layer 12. In the active layer 22, when an electric field is applied, light is generated by coupling of electron-hole pairs. Preferably, the thickness of the active layer may be 10 to 200 nm, but is not limited thereto. The position of the active layer may be varied depending on the type of the LED. Since the emission of the ultra-small LED is not limited to blue, there is no limitation in using other kinds of III-V semiconductor materials as the active layer when the emission colors are different.

Next, the second conductive semiconductor layer 23 formed on the active layer 22 will be described.

When the very small LED device is a blue light emitting device, a second conductive semiconductor layer 23 is formed on the active layer 22, and the second conductive semiconductor layer 23 is formed of at least one p-type semiconductor layer be used, the p-type semiconductor layer is a semiconductor material having a compositional formula of _{in x Al y Ga 1 -x- y} N (0≤x≤1, 0 ≤y≤1, 0≤x + y≤1) , for example in, At least one of InAlGaN, GaN, AlGaN, InGaN, AlN, InN, and the like may be selected, and a second conductive dopant (e.g., Mg) may be doped. The light emitting structure includes at least the first conductive semiconductor layer 21, the active layer 22, and the second conductive semiconductor layer 23 as a minimum component, and a different phosphor layer, An active layer, a semiconductor layer, and / or an electrode layer. Preferably, the thickness of the second conductive semiconductor layer 23 is 50 nm to 500 nm But is not limited thereto. Since the light emission of the ultra-small LED is not limited to blue, there is no limitation in using other types of III-V semiconductor materials as the p-type semiconductor layer when the emission colors are different.

In addition, according to a preferred embodiment of the present invention, the ultra miniature LED device may further include a first electrode layer formed under the first conductive semiconductor layer and a second electrode layer formed over the second conductive semiconductor layer.

Specifically, FIG. 6 is a perspective view illustrating an exemplary embodiment of an ultra-miniaturized LED device according to the present invention. Referring to FIG. 6, a first electrode layer 11 and a second conductive semiconductor layer 23 are formed under the first conductive semiconductor layer 21, And the second electrode layer 12 formed thereon.

The first electrode layer 11 and the second electrode layer 12 may be made of a metal or a metal oxide used as an electrode of a typical LED element and may be made of chromium (Cr), titanium (Ti), aluminum (Al), gold (Au), nickel (Ni), ITO, oxides or alloys thereof, or the like may be used alone or in combination. The thickness of the first electrode layer 11 and the thickness of the second electrode layer 12 may be 1 to 100 nm, but are not limited thereto. When the first electrode layer 11 and the second electrode layer 12 are included in the ultra-small LED element, the first semiconductor layer 21 and / or the second semiconductor layer 23 and a metal ohmic layer There is an advantage that the metal ohmic layer can be formed at a temperature lower than the temperature required in the forming step.

In order to prevent a short circuit due to the contact between the active layer 22 of the ultra miniature LED device and the electrode line included in the ultra miniature LED electrode assembly, the ultra miniature LED device included in the ultra miniature LED electrode assembly according to the present invention includes at least an active layer 22 may be included on the outer surface of the device. It is also preferable to insulate the outer surface of any one or more of the first semiconductor layer 21 and the second semiconductor layer 23 to prevent the deterioration of the durability of the ultra-small LED element through electrical short- The coating 30 can be coated.

Specifically, in FIG. 6, the insulating film 30 covers the outer surfaces of the first conductive semiconductor layer 21, the active layer 22, and the second conductive semiconductor layer 23.

The insulating coating 30 serves to prevent an electrical short circuit that occurs when the active layer included in the ultra-small LED element contacts the electrode. In addition, the insulating coating 30 protects the outer surface including the active layer of the ultra-miniaturized LED device, thereby preventing defects on the external surface of the device, thereby preventing a decrease in luminous efficiency.

If each of the ultra-small LED elements can be disposed between and connected to two different electrodes, it is possible to prevent an electrical short circuit that occurs due to the contact of the active layer with the electrodes. However, it is physically difficult to mount a miniature LED device of nano unit on an electrode. Accordingly, when the miniature LED element is self-aligned between two different electrodes by applying power as in the present invention, the micro LED element changes its position such as movement and alignment between two different electrodes. In this process, The outer surface of the active layer 22 of the device may be in contact with the electrode line, so that an electrical short circuit may frequently occur.

On the other hand, when the ultra-small LED element is erected upright on the electrode, the problem of electrical short-circuiting caused by contact between the active layer and the electrode line may not occur. That is, since the ultra-small LED element can not be erected upright on the electrode, the active layer and the electrode line may contact only when the LED element is laid on the electrode. In this case, the problem of not connecting the ultra-small LED element to two different electrodes There is no problem of electric short-circuit.

7 is a vertical cross-sectional view of a conventional micro-electrode assembly. The first semiconductor layer 71a of the first micro-LED element 71 is connected to the first electrode line 61, and the second semiconductor layer 71c are connected to the second electrode line 62 and the first ultra miniaturized LED element 71 is connected to the upper and lower electrodes 61 and 62 upright. 7, if the first ultra-small LED element 71 is connected to both electrodes at the same time, the active layer 71b of the device is not likely to contact any one of the two electrodes 61 and 62, Electrical shorting due to contact between the electrodes 71 and 62 and the electrodes 71 and 62 may not occur.

7, the second micro-LED element 72 is laid on the first electrode 61. In this case, the active layer 72b of the second micro-LED element 72 is in contact with the first electrode 61 . However, at this time, there is a problem that the second ultra-small LED element is not connected to the first electrode 61 and the second electrode 62, but the problem of electrical short-circuiting does not occur. Accordingly, if the insulating layer is coated on the outer surfaces of the first semiconductor layer 71a, the active layer 71b, and the second semiconductor layer 71c of the first ultra-small LED element 71 included in the electrode assembly shown in FIG. 7, The insulating coating has only the object and effect of reducing the luminous efficiency through prevention of damages to the outer surface of the ultra-small LED element.

However, unlike the conventional miniature electrode assembly shown in FIG. 7, the present invention is different from the conventional miniature electrode assembly shown in FIG. 7 in that two different electrodes are formed on the same plane (see FIG. 3) The problem of electrical short-circuiting due to the contact between the active layer and the electrode of the ultra-small LED element, which has not occurred in the conventional miniature electrode assembly, necessarily arises. Therefore, in order to prevent this, the ultra-small LED device may require an insulating film covering at least the entire outer surface of the active layer portion on the outer surface of the device.

Further, in the ultra-small LED device having a structure in which the first semiconductor layer, the active layer, and the second semiconductor layer are sequentially and vertically arranged like the ultra-small LED device included in the micro-electrode assembly according to the present invention, none. In addition, in the LED device having such a structure, the position of the active layer is not located in the center in the longitudinal direction of the device, but may be biased toward the specific semiconductor layer, so that the possibility of contact between the electrode and the active layer can be further increased. Accordingly, the insulating film is advantageous in achieving the object of the present invention by enabling the device to be electrically connected to two different electrodes regardless of the position of the active layer in the device.

8 is a plan view and a vertical cross-sectional view of an ultra-small LED device connected to a first electrode and a second electrode according to a preferred embodiment of the present invention. The active layer 121b of the first ultra-small LED elements 121a, 121b and 121c is not located at the center of the first ultra-small LED element 121 but is largely shifted to the left as shown in the sectional view AA in FIG. 8. In this case, Is likely to come into contact with the electrode 131, so that an electrical short circuit may occur. This may cause a failure of the miniature LED electrode assembly. In order to solve the above-mentioned problems, an ultra-small LED element included in the present invention may be coated with an insulating coating on an outer surface including an active layer. Due to the insulating coating, A short circuit may not occur even if the electrode 121b covers the electrode 131.

The insulating film 30 is preferably silicon nitride (Si ₃ N _4), silicon dioxide (SiO _2), aluminum oxide (Al ₂ O _3), hafnium oxide (HfO _2), yttrium oxide (Y ₂ O _3), and Titanium dioxide (TiO ₂ ), more preferably, the above-described components but may be transparent, but are not limited thereto. In the case of a transparent insulating coating, the insulating coating 30 functions as the above-mentioned insulating coating, and coating of the insulating coating can minimize the reduction in the luminous efficiency which may occur.

According to a preferred embodiment of the present invention, the insulating coating 30 may not be coated with an insulating coating on at least one of the first electrode layer 11 and the second electrode layer 12 of the ultra-small LED element, More preferably, the two electrode layers 11 and 12 may not be coated with an insulating coating. This is because the two electrode layers 11 and 12 must be electrically connected to each other. If the insulating coating 30 is coated on the two electrode layers 11 and 12, the electrical communication may be interrupted, There is a problem that the light emission itself may not be attained because it is not reduced or electrically communicated. However, if the two electrode layers 11 and 12 of the ultra-small LED element are in electrical communication with each other, there is no problem in light emission of the ultra-small LED element, and the remaining electrode layers 11 and 12 except for the end portions of the two electrode layers 11 and 12 , 12) may include an insulating coating (30).

According to a preferred embodiment of the present invention, the ultra miniature LED device may include a hydrophobic coating coated on the outer surface of the insulating coating to prevent agglomeration among the devices.

Specifically, in FIG. 6, the hydrophobic coating 40 coated on the outer surface of the insulating coating 30 can be identified. According to a preferred embodiment of the present invention, the ultra miniature LED device may further include a hydrophobic coating 40 on the insulation coating 30. The hydrophobic film 40 has hydrophobic properties on the surface of the ultra-small LED device to prevent aggregation between the LED devices. When the ultra-small LED device is mixed with a solvent, cohesion between the ultra-small LED devices is minimized, It is possible to eliminate the problem of characteristic deterioration and make it possible to position each of the ultra-small LED elements more easily when the power source is applied to the electrode line.

The hydrophobic coating 40 may be formed on the insulating coating 30. In this case, usable hydrophobic coatings can be used without limitation as long as they can be formed on the insulating coating and prevent agglomeration phenomenon between the ultra-small LED elements. Preferably, octadecyltrichlorosilane (OTS) and fluoro Self-assembled monolayers (SAMs) such as fluoroalkyltrichlorosilane and perfluoroalkyltriethoxysilane, fluoropolymers such as Teflon and Cytop, and the like, They may be used singly or in combination, but are not limited thereto.

Meanwhile, the length of the ultra small LED device included in the ultra miniature LED electrode assembly according to the present invention can satisfy the following relational expression 1 for electrical connection between the ultra small LED device and two different electrodes. Even if a very small LED element is not electrically connected even though it is self-aligned to an electrode line, even if a power source is applied to an electrode line, a very small LED element which is not electrically connected does not emit light, Can be.

 [Relation 1]

0.5? H? X + Y + 2Z. Preferably, the relation 1 satisfies Z? H <X + Y + 2Z, more preferably satisfies Z? H? X + Y + Z , Where X, Y and Z may be 100 nm < X &lt; / = 10 mu m, 100 nm &lt; Wherein X is a length of a first electrode width included in an electrode line, Y is a length of a second electrode width, Z is a distance between a first electrode and a second electrode adjacent to the first electrode, H corresponds to the length of the ultra-small LED element. Here, when the first electrode and the second electrode are plural, the distance Z between the two electrodes may be the same or different.

The portion where the ultra-small LED element is electrically connected to two different electrodes may include at least one of the first electrode layer and the first conductive semiconductor layer (or at least one of the second conductive semiconductor layer and the second electrode layer, ).

 If the length of the ultra-small LED element is significantly smaller than the distance between two different electrodes, the ultra-small LED element may be difficult to simultaneously connect to two different electrodes. Accordingly, the length of the ultra miniature LED according to the present invention may be a very small LED element satisfying 0.5Z &lt; If 0.5Z &lt; / = H is not satisfied in Equation 1, the micro LED device is not electrically connected to the first electrode and the second electrode, and the micro LED device is connected to only one of the first electrode and the second electrode This can be. 8, the second ultra-small LED element 122 may be electrically connected between the first electrode 111 and the second electrode 131, so that the ultra-small LED element included in the present invention And Z &lt; H in the relational expression (1).

On the other hand, when the length H of the ultra-small LED element is long in consideration of the width X of the first electrode, the width Y of the second electrode, and the distance Z between the first and second electrodes 8 may be independently connected to the first electrode 112 and the second electrode 132, respectively. If the active layer of the third ultra-small LED element 123 is not located at the central portion of the device and the outer surface of the device is not coated with an insulating coating covering at least the outer surface of the active layer portion, Which may cause an electrical short between the elements 123. [ However, the ultra miniature LED device according to the present invention includes an insulating film covering at least the entire outer surface of the active layer portion on the outer surface, and a portion other than both ends of the ultra-small LED device, such as the third ultra- Even when connected to the electrodes, they can be electrically connected at the same time without causing an electrical short circuit.

However, the length (H) of the ultra-small LED element is longer considering the width length (X) of the first electrode, the width length (Y) of the second electrode and the electrode spacing distance (Z) If H < X + Y + 2Z in the above formula (1) is not satisfied, there may be a problem that the micro LED device which is not electrically connected is included in the micro LED electrode assembly.

Specifically, in FIG. 8, the fourth ultra-small LED element 124 is simultaneously connected to the two second electrodes 132 and 133 and the first electrode 112. In this case, the length H) is a case in which H < X + Y + 2Z in the above relational expression 1 is dissatisfied. In this case, the fourth ultra miniature LED device 124 has a problem in that the active layer and the second electrode 132 or 133 or the first electrode 112 are brought into contact with each other to cause an electrical short circuit. If the fourth ultra miniature LED element 124 includes an insulating coating coated on the outer surface of the active layer so that the problem of electrical shorting is eliminated, the fourth ultra miniature LED element 124 is formed on the two second electrodes 132, And the fourth ultra-small LED device 124 may not emit light even when power is applied to the electrode line. In this case, This can be.

In addition, if the length H of the ultra-small LED element is longer than that of the fourth ultra-small LED element 124, both ends of the ultra-small LED element are electrically connected to the first electrode 111 and the second electrode 133 However, if the length of the ultra-small LED device is increased, the efficiency of light may be lowered, which may result in a problem that the desired ultra-small LED electrode assembly can not be manufactured.

Accordingly, the length (H) of the ultra-small LED element can satisfy H < X + Y + 2Z in the relational expression (1).

On the other hand, even if the length H of the ultra-small LED element satisfies X + Y + Z <H <X + Y + 2Z in the relational expression 1, the active layer of the ultra-small LED element is biased toward a specific conductive semiconductor layer In the case of an active layer coated with an insulating film rather than an electrode layer and / or a conductive semiconductor layer, the electrical short-circuit is not caused due to the insulating coating, but the micro LED element is electrically connected to the electrode line There may be a problem that may not be possible.

Specifically, in FIG. 8, the fifth ultra-small LED element 125 is connected to the first electrode 111 and the second electrode 131 at the same time. 8, the position of the external surface of the fifth ultra-small LED element 125 connected to the first electrode 111 is a portion of the active layer 125c, and the electrode layer 125a and the conductive semiconductor layer 125b It can be confirmed that it is not connected to the first electrode 111. In this case, since the insulating layer is coated on the active layer 125c of the fifth ultra-small LED element 125, the electrode layer 125a and the conductive semiconductor layer 125b are electrically connected to the first electrode 111, So that the fifth ultra-small LED element 125 may not emit light when the power is applied to the electrode line.

Further, even when the length H of the ultra-small LED element satisfies X + Y + Z <H <X + Y + 2Z in the relational expression 1 and the ultra-small LED element is electrically connected to the electrode, There may be cases where a very small LED electrode assembly can not be realized. 8, the sixth ultra-small LED element 126 is electrically connected to the first electrode 111 and the second electrode 131, so that there is no problem in emitting light when power is applied to the electrode line. However, The electrode line area occupied by one ultra-small LED element for mounting increases due to the oblique mounting without being vertically aligned with the electrode 111 and the second electrode 131. As a result, As the number of ultra-small LED elements that can be mounted on the LED element mounting region decreases, it may be difficult to implement a very small LED electrode assembly that emits a desired amount of light.

Accordingly, according to a preferred embodiment of the present invention, the length (H) of the ultra-small LED element can satisfy H? X + Y + Z in the relational expression (1). In this case, it is possible to realize an electrically connected miniature LED electrode assembly which is electrically short-circuited, irrespective of the position of the active layer coated with the insulating film in the longitudinal direction in the micro LED device, and the area of the electrode line occupied by one micro LED device is reduced The number of very small LED elements which can be mounted on the electrode line of a limited area can be increased, which can be very advantageous for realizing a desired ultra-small LED element.

 The step (1) according to the present invention for injecting a solution containing an ultra-small LED element into an electrode line including a first electrode and a second electrode comprises the steps of: 1-1) And a second electrode formed to be coplanar with the first electrode; 1-2) forming an insulating barrier surrounding the electrode line region on which the micro LED device is mounted on the base substrate; And 1-3) applying a plurality of ultra-small LED elements to the electrode line region surrounded by the insulating barrier ribs.

First, the step 1-1) may include fabricating an electrode line including a base substrate, a first electrode formed on the base substrate, and a second electrode formed on the same plane as the first electrode, . The specific method of forming the electrode in the step 1-1) will be omitted as described above.

Next, steps 1-2) may include forming an insulating barrier surrounding the electrode line area on which the micro LED device may be mounted on the base substrate.

In the insulating barrier, the ultra miniature LED element is prevented from spreading to other than the electrode line region where the ultra miniature LED element is to be mounted when the ultra miniature LED element is inserted into the electrode line in a step 1-3) So that the devices can be concentrated and arranged.

The insulating barrier rib may be manufactured through a manufacturing process described later, but the method of manufacturing the insulating barrier rib is not limited thereto.

9 is a schematic view showing a manufacturing process of forming an insulating barrier rib 107 on an electrode line formed on a base substrate 100 and a base substrate 100 according to a preferred embodiment of the present invention. The insulating barrier ribs 107 can be manufactured after the electrode lines 103a and 103b deposited on the base substrate 100 are manufactured as shown in FIGS.

9A, the insulating layer 104 may be formed on the base substrate 100 and the electrode lines 103a and 103b formed on the base substrate 100, as shown in FIG. 9B. The insulating layer 104 may be an insulating material typically used in the art, and may be made of silicon dioxide (SiO _2, Inorganic insulators such as silicon nitride (Si ₃ N ₄ ), aluminum oxide (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), yttrium oxide (Y ₂ O ₃ ) and titanium dioxide (TiO ₂ ) It can be any one or more. When the insulating layer 104 is coated on the base substrate 100 and the electrode lines 103a and 103b formed on the base substrate 100, the inorganic insulating layer may be formed by a chemical vapor deposition method, an atomic layer deposition method, a vacuum Evaporation method, e-beam evaporation method, and spin coating method, and preferably, it may be a chemical vapor deposition method, but the method is not limited thereto. The method of coating the polymer insulating layer may be a spin coating method, a spray coating method, Printing, and the like. The coating may be spin coating, but is not limited thereto. Specific coating methods can be performed by a method known in the art. The thickness of the insulating layer 104 to be coated is not less than one-half of the ultra-small LED radius so as not to flood the micro-LEDs and not affect the post-process, And more preferably 0.3 to 10 mu m. If the above range is not satisfied, there arises a problem that it is difficult to manufacture a product including the LED electrode assembly due to the influence of the post-process. If the thickness of the insulation layer is too thin, The effect of preventing the spreading property of the LED element may be insufficient, and the solution containing the ultra-small LED element may overflow outside the insulating barrier.

Then, a photoresist (PR) 105 may be coated on the insulating layer 104. The photoresist may be a photoresist commonly used in the art. The method of coating the photoresist on the insulating layer 104 may be any one of spin coating, spray coating and screen printing, preferably spin coating, but is not limited thereto. And can be carried out by a known method. The thickness of the photoresist 105 to be coated is preferably thicker than the thickness of the insulating layer coated with the mask used in the etching, so that the thickness of the photoresist 105 may be 1 to 20 μm. However, the thickness of the photoresist 105 to be coated may be changed in accordance with the purpose.

After the photoresist layer 105 is formed on the insulating layer 104 as described above, a mask 106 corresponding to the horizontal cross-sectional shape of the insulating partition is placed on the photoresist layer 105 as shown in FIG. 9C, It is possible to expose ultraviolet rays on the upper surface of the substrate 106.

Thereafter, the exposed photoresist layer is dipped in a conventional photoresist solvent, thereby removing the exposed photoresist layer portion corresponding to the area of the electrode line where the micro LED device is to be mounted, can do.

Next, the photoresist layer may be removed to remove the exposed portion of the insulating layer through the etching for the exposed region of the insulating layer. The etching may be performed by wet ethching or dry ethching, preferably by dry etching. A specific method of the etching method can be performed by a method known in the art. Specifically, the dry etching may be performed by any one of plasma etching, sputter etching, reactive ion etching, and reactive ion beam etching. However, the specific etching method is not limited to the above description. When the exposed insulating layer is removed through etching, the base substrate 100 and the electrode lines 103a and 103b may be exposed as shown in FIG. 9E.

Next, as shown in FIG. 9F, the base substrate 100 is removed by using a photoresist remover such as acetone, 1-methyl-2-pyrrolidone (NMP), or dimethyl sulfoxide (DMSO) The insulating partition wall 104 'can be manufactured in a region other than a region (P in FIG. 9) where the micro-LED element is substantially mounted on the base substrate 100 by removing the photoresist layer 105 coated on the substrate 100 .

The method may further include a step of applying a plurality of ultra-small LED elements to an electrode line region surrounded by the insulating barrier ribs in a step 1-3).

10A and 10B are perspective views illustrating a manufacturing process of a micro LED electrode assembly according to a preferred embodiment of the present invention. Referring to FIG. 10A, electrode lines 110 and 130 surrounded by an insulating barrier 150 formed on a base substrate 100, A plurality of ultra-small LED elements can be put in the region. In this case, the micro-miniaturized LED element can be directly positioned in the target electrode line region as compared with the case of FIG. 1A. Further, in the step (2) described below, the micro LED element is placed in an area where there is no intended electrode line area and / or an electrode line in order to mount the micro LED element by spreading the micro LED element to the outside of the electrode line There is an advantage that it can be prevented.

As a non-limiting example, the method of injecting the ultra-small LED element into the electrode line is not limited to the present invention. For example, the core-shell structure including the core portion and the polymer shell portion surrounding the ultra- The miniature LED device may be charged into the electrode line. In this case, the specific type of the polymer component forming the shell part can be used without limitation as long as it does not affect the ultra-small LED element to be supported on the core part. Preferably, however, Lt; RTI ID = 0.0 &gt; polymer. &Lt; / RTI &gt; The diameter and shape of the particles may be changed according to the purpose, and are not particularly limited in the present invention. 10B and FIG. 10C are the same as those of FIGS. 1B and 1C in the description of step (2) according to the present invention.

Next, in step (2) according to the present invention, in order to simultaneously connect a plurality of very small LED elements to the first electrode and the second electrode, solvent is applied to the electrode line, and power is applied to the electrode line, And self-aligning the LED elements.

1B is a perspective view illustrating a process of applying a solvent 140 to the electrode lines 110 and 130 in which the ultra-small LED elements 120 are randomly dispersed and applying power. Explain.

The solvent 140 can smoothly disperse and move the ultra-small LED element 120 without causing physical and chemical damage to the ultra-small LED element 120, and at the same time, Can be used without. However, it may preferably be any one or more selected from the group consisting of acetone, water, alcohol and toluene, more preferably acetone.

The solvent 140 may be added in an amount of 100 to 12,000 parts by weight based on 100 parts by weight of the ultra-small LED element to be injected in the step (1). If the amount of the solvent exceeds 12,000 parts by weight, the amount of the solvent is excessively large. As a result, the ultra-small LED element is spread by the solvent to a region other than the target electrode line region, There is a problem in that the movement and alignment of the miniature LED elements may be hindered if the amount of the ultrafine LEDs is less than 100 parts by weight.

Next, a method of self-aligning the ultra-small LED element in the electrode line will be described.

The plurality of ultra-small LED devices included in the micro LED electrode assembly according to the present invention are self-aligned by applying power to the first electrode and the second electrode, and are simultaneously connected to the first electrode and the second electrode as shown in FIG.

If a typical LED element is directly physically disposed, it can be simultaneously connected to different electrodes formed on the same plane. For example, a common LED element may be arranged by laying down manually between different electrodes of a planar electrode.

However, since it is difficult to physically arrange the miniature LED elements directly as in the present invention, it is not possible to simultaneously connect the miniature LED elements to different miniature electrodes spaced on the same plane. In addition, when the ultra-small LED element is cylindrical, it may be simply inserted into the electrode, which may cause a problem of being rolled on the electrode due to the cylindrical shape without being self-aligned. Accordingly, the present invention can solve the above-described problems by applying the power to the electrode line so that the micro LED elements are connected to two different electrodes at the same time by themselves.

Preferably, the power source may be a varying power source having an amplitude and a period, and the waveform may be a pulse file composed of sine waves such as sine waves or non-sinusoidal waveforms. As an example AC power is applied, 0V, 30V, 0V, and 30V are repeatedly applied to the first electrode for 1000 times per second, and 30V, 0V, 30V, and 0V are repeatedly applied to the second electrode So that a fluctuating power source having an amplitude and a period can be formed.

Preferably, the voltage (amplitude) of the power supply may be between 0.1V and 1000V, and the frequency may be between 10Hz and 100GHz. The self-aligned ultra-small LED devices are contained in a solvent and are injected into an electrode line. The solvent can evaporate while falling onto the electrode, and the ultra-small LED devices are asymmetric As the charge is induced, the micro-LED device can self-align between two opposing electrodes with opposite ends facing each other. Preferably, the ultra-small LED element can be simultaneously connected to two different electrodes by applying power for 5 to 120 seconds.

Meanwhile, the number N of ultra-small LED elements simultaneously connected to the first electrode and the second electrode in the step (2) may depend on several variables that can be adjusted in the step (2). The variables include the voltage (V) of the applied power source, the frequency (F, Hz) of the power source, the concentration of the solution containing the ultra-small LED element (C, the weight of the ultra-small LED), the spacing distance Z between the two electrodes, The aspect ratio of the LED (AR, where AR = H / D and D is the diameter of the miniature LED). Accordingly, the number N of ultra-small LED elements connected to the first electrode and the second electrode at the same time depends on the voltage V, the frequency F, the concentration C of the solution containing the ultra-small LED element, and the aspect ratio AR) and may be inversely proportional to the spacing distance Z between the two electrodes.

This is because the very small LED elements are self-aligned between two different electrodes by induction of an electric field formed by the potential difference of the two electrodes, and as the intensity of the electric field is increased, the number of ultra-small LED elements connected to the electrodes may increase, May be proportional to the potential difference (V) of the two electrodes and may be inversely proportional to the spacing distance (Z) between the two electrodes.

Next, in the case of the concentration of the solution (C, ultra-small LED weight%) containing the ultra-small LED device, the number of LED devices connected to the electrode may increase as the concentration increases.

Next, when the frequency of the power source (F, Hz) is varied according to the frequency, the number of ultra-small LED elements connected to the two electrodes may increase as the frequency increases. However, since the charge induction may disappear when the value exceeds a certain value, the number of very small LED elements connected to the electrode may be reduced.

Finally, as the aspect ratio of the ultra-small LED element increases, the induced electric charge due to the electric field increases, so that a larger number of ultra-small LED elements can be aligned. Also, considering the electrode line having a limited area in terms of space where the ultra-small LED elements can be aligned, when the length of the ultra-small LED element is fixed, the diameter of the ultra-small LED element is reduced, The number of ultra-small LED elements that can be used can be increased.

The present invention has an advantage in that it is possible to control the number of the LED elements connected to the electrode according to purposes by controlling various factors as described above.

On the other hand, depending on the aspect ratio of the ultra-small LED element, it may be difficult to self-align the ultra-small LED element even if power is applied to the electrode line in the step (2) according to the present invention. Accordingly, according to an exemplary embodiment of the present invention, the aspect ratio of the ultra-small LED device included in the present invention can be 1.2 to 100, more preferably 1.2 to 50, still more preferably 1.5 to 20, And particularly preferably from 1.5 to 10. If the aspect ratio of the ultra-small LED element is less than 1.2, there is a problem that the ultra-small LED element may not self-align even if power is applied to the electrode line. If the aspect ratio exceeds 100, the voltage of the power source necessary for self- However, it may be difficult to manufacture a device having an aspect ratio exceeding 100 in the limit of an etching process when a micro LED device is manufactured by dry etching.

Preferably, in the step (2), the number of the ultra-small LED elements per 100 × 100 μm ² of the area of the electrode line (unit electrode) on which the ultra-small LED element can be mounted may be 2 to 100,000, May be 10 to 10.000. By including a plurality of ultra-small LED devices per mini LED electrode assembly, it is possible to minimize the functional deterioration or the loss of function of the LED electrode assembly due to some defects. In addition, if the number of ultra-small LED elements exceeds 100,000, manufacturing cost increases and there may be a problem in alignment of ultra-small LED elements.

Meanwhile, in the method of fabricating a micro LED electrode assembly according to a preferred embodiment of the present invention, in the step (3) after the step (2), a metal ohmic layer ; . &Lt; / RTI &gt;

The reason why the metal ohmic layer is formed at the connection portion is that when the power is applied to two different electrodes connected to a plurality of very small LEDs, the very small LED elements emit light, which may cause a large resistance between the electrode and the very small LED element And forming a metal ohmic layer to reduce the resistance.

Specifically, the metal ohmic layer may be formed by the following process, but it is not necessarily formed by the following process, and any method for forming a conventional metal ohmic layer may be used without limitation.

First, a photoresist may be coated on the upper portion of the micro LED electrode assembly having been subjected to the step (2) to a thickness of 2 to 3 탆. The coating is preferably performed by any one of a spin coating method, a spray coating method and a screen printing method, but is not limited thereto. Thereafter, ultraviolet rays are irradiated in the direction of the photoresist layer coated on the base substrate of the ultra-small LED electrode assembly to cure the remaining photoresist layer except for the photoresist layer above the electrode, and then cured using a conventional photoresist solvent The photoresist layer on the upper portion of the electrode can be removed.

 Preferably, gold or silver is vacuum deposited or electrochemically deposited on top of the photoresist-removed electrode, or gold nanocrystals or silver nanocrystals are coated by electric spaying, . The thickness of the metal layer to be coated may be preferably 5 to 100 nm, but is not limited thereto.

Then, using a photoresist stripper (PR stripper) of acetone, 1-methyl-2-pyrrolidone (NMP) and dimethyl sulfoxide (DMSO) After the removal, the metal ohmic layer can be formed between both ends of the micro-LED device, which are not coated with the insulating coating, through the heat treatment at 500 to 600 ° C. and between the electrodes.

According to another aspect of the present invention, An electrode line including a first electrode formed on the base substrate and a second electrode formed on the same plane as the first electrode; And a plurality of ultra-small LED elements connected to the first electrode and the second electrode at the same time.

According to a preferred embodiment of the present invention, the width (X) of the first electrode, the width (Y) of the two electrodes, the distance Z between the first electrode and the second electrode adjacent to the first electrode, The length (H) of the ultra-small LED element can satisfy the following relational expression (1).

[Relation 1]

0.5Z? H <X + Y + 2Z where 100nm <X? 10μm, 100nm <Y? 10μm, and 100nm <Z? 10μm.

A detailed description of the electrode line including the base substrate, the first electrode and the second electrode, the ultra-miniaturized LED element, and the relational expression 1 is the same as the description of the manufacturing method according to the present invention and is not described in the manufacturing method .

11 is a perspective view and a partially enlarged view of a miniature LED electrode assembly manufactured in accordance with a preferred embodiment of the present invention. Referring to FIG. 11, first and second electrodes 410 and 411 formed on a base substrate 400, 410 and 411, and a plurality of ultra miniature LED devices 420 connected to the first and second electrodes simultaneously.

The advantage obtained by positioning the first electrode 411 and the second electrode 431 on the same plane is that it is very difficult to vertically connect the electrode and the electrode in a three-dimensional shape in the case of an ultra-small LED device having a nano unit size, The micro LED element can be laid down and connected so that the micro LED element does not need to be upright and bonded to the electrode.

In addition, since the electrodes are formed on the same plane, the ultra-small LED elements can be connected to the base substrate by being laid on the base substrate, thereby greatly improving the extraction efficiency of the ultra-small LED elements. Even more preferably, the ultra-small LED elements may lie parallel to the base substrate.

11, the ultra miniature LEDs 421 are connected to the first electrode 412 and the second electrode 432 at the same time and they are laid in parallel to the base substrate.

More specifically, FIG. 12A is a SEM photograph of a micro LED electrode assembly according to a preferred embodiment of the present invention. In a preferred embodiment of the present invention, the first electrode has a width of 3 탆, the second electrode has a width of 3 탆, the interval between the electrodes is 2 탆, and the thickness of the electrode is 2 탆. In addition, the ultra-small LED connected to the electrode has a length 2㎛ the radius is 500 nm, the concentration injected paste for connecting the electrode was mixed the compact LED is 1.0 part by weight based on 100 parts by weight of acetone. Further, in order to self-align the ultra-small LED element to the electrode, a voltage V _AC = 30 V, a frequency 500 kHz Was applied for 1 minute.

As can be seen from the SEM photograph, it can be seen that the ultra-miniaturized LED is located over the first electrode and the second electrode, or the LED element is connected when the LED is connected and connected between the two electrodes.

12B and 12C are blue electro-luminescence photographs of a micro LED electrode assembly according to a preferred embodiment of the present invention, in which FIG. 12B is a photograph taken in a bright room, and FIG. 12C is a photograph taken in a dark room. In a preferred embodiment of the present invention, the miniature LED device includes a plurality of miniature LED electrode assemblies formed on an area of 0.6 cm x 0.7 cm in width and length, Not only shows a state in which light is emitted from the point but also shows that they are combined to emit light.

This is the first time in the literature that a very small LED element can be easily assembled on a large area electrode using a very small LED element to realize surface emission, and various types of point light sources, It is shown that the application of the surface light source is possible. In addition, it shows that application to display can be possible if the point light source is reduced to the color cell level and integrated. In addition, when a transparent base substrate is used as the substrate, it can be applied as a transparent light source and a display. Furthermore, the use of a flexible base substrate shows that it can be implemented as a flexible light source or a flexible display.

Therefore, the ultra miniature LED device fabricated by assembling the ultra miniature LED device parallel to the base substrate on the alternate electrode according to the preferred embodiment of the present invention is a high efficiency LED device having excellent light extraction efficiency, It can be realized in various forms such as a surface light source, a light source, and a color cell as well as a point light source.

12B and 12C, a metal ohmic layer may be further formed between the ultra-small LED element and the electrode so as not to include the metal ohmic layer, so that the resistance between the ultra-small LED element and the electrode The luminous efficiency can be further increased.

FIG. 13 is an electroluminescence spectrum of an ultra miniature LED electrode assembly according to a preferred embodiment of the present invention, which is a result of a spectrophotometer measuring electroluminescence of a preferred embodiment of the present invention. The electroluminescent blue microdevice LED device is an ultra-small LED device fabricated using a wafer substrate. The microdroplet LED device is an ultra-small type LED device using various dry etching processes and laser lift-off processes, 13 shows that even after the LED device is self-assembled between the different electrodes, the original blue light emission is well maintained as in the emission spectrum of FIG.

This indirectly shows that the defects that may occur during the process of fabricating the miniaturized LED device in which the first electrode layer, the first conductive semiconductor layer, the active layer, the second conductive semiconductor layer, and the second electrode layer are sequentially arranged are minimized Giving. That is, stress and defects existing on the wafer substrate during the process of fabricating a very small LED device using a blue wafer are removed through a process of miniaturizing the size of the LED device and an etching process, Miniature LED devices have been fabricated and show that the ultra-small LED devices having excellent crystallinity emit excellent light even when they are self-aligned to different electrodes.

Meanwhile, the ultra-small LED device of the present invention is connected to the electrode in a &quot; lying &quot; shape parallel to the base substrate, so that the ultra-small LED electrode assembly of the present invention can have remarkably excellent light extraction efficiency. In general, the performance of LED devices is evaluated by external quantum efficiency.

The external quantum efficiency is expressed as a ratio of the number of photons emitted to the outside of the LED, that is, the number of photons, to the atmosphere for a unit time with respect to the number of carriers injected into the LED element per unit time. The external quantum efficiency satisfies the following relationship between the internal quantum efficiency and the light extraction efficiency.

[Relational expression] External photon efficiency = internal photon efficiency × light extraction efficiency

The internal photon efficiency means the ratio of the number of photons emitted from the active layer during the unit time to the number of carriers injected into the LED element per unit time and the light extraction efficiency is expressed by the unit of the number of photons emitted from the active layer The ratio of the number of photons leaving the atmosphere for a period of time. As a result, it is important to improve their efficiency in order to improve the performance of the LED device.

However, in terms of light extraction efficiency, extraction efficiency of light radiated into the air through the upper and lower electrodes, the n conductive semiconductor layer, and the p conductive semiconductor layer of a very thin LED element is very low. This is because most of the light generated from the thin film LED element is totally reflected by the difference in refractive index at the interface between the high refractive index semiconductor layer and the low refractive index air layer and is trapped in the semiconductor layer and thus a large amount of light generated in the active layer is extracted This is due to the fact that the LED element is re-absorbed or disappears into the heat inside the LED element, which is caused by manufacturing an LED element using a conventional thin film structure.

In order to solve such a problem, in the present invention, the ultra-small LED element is laid down and connected to the electrode to eliminate the flat interface between the high refractive index semiconductor layer and the air layer, so that the probability of total internal reflection is minimized, So that most of the light is emitted to the outside. Accordingly, it is possible to provide a very small LED electrode assembly that solves the conventional problem of light extraction deterioration.

14A is a TEM photograph showing the entirety of a columnar ultra-small LED device, FIG. 15B is a TEM photograph showing the entire surface of the ultra-small LED device, It is a high resolution TEM photograph. 15B, it can be seen that the atomic arrangement of the InGaN crystal near the surface of the ultra-small LED element is regularly arranged even after the dry etching process and the laser lift-off process to fabricate the ultra-small LED have. This shows directly that the crystallinity of the ultra-small LED device obtained through various manufacturing processes is very excellent, thereby showing that it is possible to fabricate a highly efficient ultra-small LED device. That is, since the manufactured ultra-small LED element has excellent crystallinity, it is excellent in internal quantum efficiency and the ultra-small LED element is horizontally aligned between the different electrodes, so that the light extraction efficiency is excellent. Thus, a high efficiency LED having excellent internal quantum efficiency and external quantum efficiency It is directly demonstrated that an ultra-small LED electrode assembly including a device can be realized.

The miniature LED electrode assembly may include a single or plural arrangement regions in which two electrodes capable of independently driving the unit electrodes, that is, the miniature LED elements, are arranged at one time, and the unit electrodes have an area of 1 to ² cm ² And even more preferably from 10 μm ² to 100 mm ² , but is not limited thereto.

If the unit electrode area included in the miniature LED electrode assembly is less than 1 占 퐉 ² , the unit electrode may be difficult to manufacture and the length of the ultra-small LED may be further reduced. If the thickness exceeds 100 cm ² , the number of ultra-small LED elements included increases, so that the manufacturing cost may increase, and there may be a problem of non-uniformity of distribution of the micro LEDs to be aligned.

Preferably, the number of micro LED devices per 100 x 100 탆 ² of the micro LED electrode assembly may be 2 to 100,000, and more preferably 10 to 10.000. By including a plurality of ultra-small LED devices per mini LED electrode assembly, it is possible to minimize the functional deterioration or the loss of function of the LED electrode assembly due to some defects. In addition, if the number of ultra-small LED elements exceeds 100,000, manufacturing cost increases and there may be a problem in alignment of ultra-small LED elements. The &quot; area of the ultra-small LED electrode assembly &quot; refers to the area of the electrode area where the ultra-small LED can be substantially mounted.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be understood that various changes and modifications may be made without departing from the scope of the present invention. For example, each component specifically illustrated in the embodiments of the present invention can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

The present invention will now be described more specifically with reference to the following examples. However, the following examples should not be construed as limiting the scope of the present invention, and should be construed to facilitate understanding of the present invention.

&Lt; Example 1 >

An electrode line as shown in FIG. 3 was fabricated on a 800 μm thick base substrate made of quartz. At this time, in the electrode line, the width of the first electrode was 3 mu m, the width of the second electrode was 3 mu m, the gap between the first and second electrodes was 2 mu m, and the thickness of the electrode was 0.2 mu m, The material of the second electrode was titanium / gold, and the area of the area where the micro LED device was mounted on the electrode line was 4.2 x 10 ⁷ 탆 ² . 9, the material of the insulating partition is silicon dioxide, and the height from the base substrate to the end of the insulating partition is 0.1 μm. In the electrode line, the very small LED element is mounted on the base substrate, (Area 4.2 x 10 &lt; ⁷ &gt; [mu] m &lt; ² &gt;), an insulating barrier rib was formed on the base substrate.

Subsequently, an ultra-small LED element having the same specifications as shown in Table 1 below and having a structure as shown in FIG. 6 and having an insulating film coated to a thickness of 0.02 mu m as shown in Table 1 below on the outer surface of the active layer portion of the ultra- In the area where the ultra-miniature LED is mounted. Then, acetone was injected into the area where the ultra-small LED element was charged, and the charged acetone was added so that acetone was 10,000 parts by weight per 100 parts by weight of the ultra-small LED element. At the same time as the above-mentioned solvent was introduced, a voltage V _AC = 30 V and a frequency of 950 kHz Was applied for 1 minute to fabricate a micro LED electrode assembly.

material Length (㎛) Diameter (탆) The first electrode layer chrome 0.03 0.6 The first conductive semiconductor layer n-GaN 1.64 0.6 Active layer InGaN 0.1 0.6 The second conductive semiconductor layer p-GaN 0.2 0.6 The second electrode layer chrome 0.03 0.6 Insulating film Aluminum oxide - 0.02 (thickness) Ultra-compact LED element - 2 0.62

&Lt; Example 2 >

A micro LED electrode assembly was fabricated in the same manner as in Example 1 except that an ultra-small LED element was dropped on an electrode line formed on a base substrate without an insulating barrier, without forming an insulating barrier.

&Lt; Example 3 >

A micro LED electrode assembly was fabricated in the same manner as in Example 1 except that the active layer of the ultra-small LED device was an ultra-small LED device having no insulating film on the outer surface of the part.

&Lt; Comparative Example 1 &

A solution prepared by mixing 100 parts by weight of acetone with 100 parts by weight of the ultra-small LED element was put into a solution instead of the ultra-small LED element, and then power was applied to the electrode line, .

<Experimental Example 1>

For the microelectrode assemblies prepared in Examples and Comparative Examples, the voltage V _AC = 30 V and the frequency 950 kHz The number of ultra small LED elements emitting blue light was observed through an optical microscope and is shown in Table 2 below.

Number of ultra-small LED devices emitting blue light Example 1 8945 Example 2 4508 Example 3 2792 Comparative Example 1 8604

Specifically, as shown in Table 2, in Example 3, which is an electrode assembly including an ultra-small LED device that does not include an insulating film in an active layer of the ultra-small LED device, The number of the LEDs is remarkably small, so that the active layer of the ultra-small LED device is in contact with the electrodes, and it can be confirmed that a lot of electric shorts have occurred.

In the case of Example 2 in which a very small LED element was placed on an electrode line without an insulating partition, the number of very small LED elements that emit blue light was smaller than in Example 1, It can be understood that the number of ultra-small LED elements electrically connected to the electrode lines is reduced as the ultra-small LED elements are dispersed in an electrode line external to which the ultra-small LED elements can not be mounted.

Also, in the case of Comparative Example 1 in which the ultra-small LED element was put in a solution state, it was confirmed that the ultra-small LED element was charged first and that the number of ultra-small LED elements emitting blue light was smaller than that of Embodiment 1 in which power was applied while dropping the solvent thereafter .

<Experimental Example 2>

The voltage required to self-align the ultra-small LED element according to the aspect ratio of the ultra-small LED element was measured. Table 3 shows the minimum voltage at which self-alignment of the ultra-small LED device was started by using the ultra-small LED device fabricated by changing the aspect ratio of the ultra-small LED device as shown in Table 3 below.

Length (H, μm) Diameter (D, 탆) Aspect ratio (AR = H / D) The applied voltage (V) Example 4 2 2 One - Example 5 2 1.7 1.2 262 Example 6 2 1.5 1.3 136 Example 7 2 1.2 1.7 73 Example 8 2 One 2 53 Example 9 2 0.8 2.5 40 Example 10 2 0.4 5 23 Example 11 2 0.2 10 15

Specifically, as can be seen from Table 3, it can be seen that the voltage of the power source required for self-aligning the micro-LED element increases remarkably as the aspect ratio of the micro-LED element becomes smaller. In the embodiment in which the aspect ratio of the micro- 4, it was impossible to self-align the ultra-small LED element to the electrode even if the voltage of the power source was increased. It can also be seen that the voltage required for self-alignment of the micro LED device was significantly increased in Example 5 and Example 6 in which the aspect ratio of the ultra-small LED device was 1.2 and 1.3, respectively, as compared with Example 7. [

<Experimental Example 3>

The microelectrode assemblies prepared in Example 1 and Comparative Example 1 were magnified 1500 times and photographed with an optical microscope. The results are shown in Fig. 15 for Example 1 and Fig. 16 for Comparative Example 1, respectively.

As can be seen from FIG. 15, in the case of Example 1, the miniature LED element is more intensively self-aligned with the intended electrode portion without being outside, whereas Comparative Example 1 of FIG. 16 shows that the ultra- It can be confirmed that the micro LED device is spread out to the outside and is self-aligned and the aggregation phenomenon is very severe among the micro LED devices.

Claims (14)

(1) applying a plurality of ultra-small LED elements to an electrode line including a base substrate, a first electrode formed on the base substrate, and a second electrode formed on the same plane as the first electrode;
(2) applying solvent to the electrode lines to simultaneously connect the plurality of micro LED elements to the first electrode and the second electrode, and applying power to the electrode lines to self-align the plurality of micro LED elements; And
(3) forming a metal ohmic layer on at least one of the first electrode and the second electrode and the connection portion of the micro LED device,
The step (1) may include: 1-1) fabricating an electrode line including a base substrate, a first electrode formed on the base substrate, and a second electrode formed on the same plane as the first electrode; 1-2) forming an insulating barrier surrounding the electrode line region on which the micro LED device is mounted on the base substrate; And 1-3) applying a plurality of ultra-small LED elements to an electrode line region surrounded by the insulating barrier ribs. The method according to claim 1,
Wherein the first electrode and the second electrode in step (1) are spaced apart from each other by a spiral arrangement or an interdigitated arrangement. The LED according to claim 1, wherein the ultra-small LED element
A first conductive semiconductor layer;
An active layer formed on the first conductive semiconductor layer; And
And a second conductive semiconductor layer formed on the active layer. The method of claim 3,
The ultra-small LED device further includes an insulating film covering at least an entire outer surface of the active layer to prevent short-circuiting caused by contact between the active layer and the electrode line of the ultra-small LED device. Gt; 5. The method of claim 4,
Wherein the ultra miniature LED device further comprises a hydrophobic coating coated on an outer surface of the insulating coating of the ultra-small LED device to prevent agglomeration of the devices. 6. The method according to any one of claims 3 to 5,
Wherein the ultra miniature LED device comprises a first electrode layer formed under the first conductive semiconductor layer and a second electrode layer formed over the second conductive semiconductor layer. The method according to claim 6,
Wherein the first electrode layer and the second electrode layer of the ultra miniature LED device are not coated with an insulating coating. The method according to claim 1,
Wherein the micro LED element has a length of 100 nm to 10 μm and an aspect ratio of 1.2 to 100. The method according to claim 1,
The width (X) of the first electrode, the width (Y) of the second electrode, the distance (Z) between the first electrode and the second electrode adjacent to the first electrode, and the length (H) (1). &Lt; / RTI &gt;
[Relation 1]
X, Y and Z are 100 nm &lt; X &lt; / = 10 mu m, 100 nm &lt; delete The method according to claim 1,
Wherein the voltage of the power source applied in the step (2) is 0.1 to 1000 V and the frequency is 10 Hz to 100 GHz. The method according to claim 1,
In the step (2), the number of the ultra miniature LED elements connected to the first electrode and the second electrode at the same time is 2 to 100,000 per 100 × 100 μm ² of the area of the electrode line on which the ultra-small LED element is mounted. Assembly manufacturing method. The method according to claim 1,
The width (X) of the first electrode, the width (Y) of the second electrode, the distance (Z) between the first electrode and the second electrode adjacent to the first electrode, and the length (H) (1). &Lt; / RTI &gt;
[Relation 1]
X, Y and Z satisfy 100nm &lt; X &lt; / = 10 mu m, 100nm &lt; delete

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