KR102583708B1 - Flexible nano-scale LED skin patch and Manufacturing method thereof - Google Patents

Abstract

The present invention relates to a flexible skin patch equipped with an ultra-small LED assembly that emits light in a specific wavelength range and an invention for manufacturing the same. It has an excellent effect of promoting vitamin D production in localized areas of the skin, and is effective in promoting localized skin psoriasis and fungus. The present invention relates to an invention that can provide a flexible skin patch that is easily attachable and detachable while having an excellent improvement or treatment effect for fungal tumors and eczema.

Description

Ultra-small-LED flexible skin patch and manufacturing method thereof {Flexible nano-scale LED skin patch and Manufacturing method thereof}

The present invention relates to a flexible skin patch equipped with an LED that is attached to the skin and emits light in a specific wavelength range, and more specifically, to a flexible skin patch equipped with an ultra-small LED assembly and an invention for manufacturing the same.

Recently, skin care and skin treatment using light has become very active. Since each cell and tissue of the skin absorbs light of a specific wavelength, light in a wavelength range appropriate for the situation is irradiated for the purpose of physiological and chemical treatment to stimulate the skin's reaction. induce.

Phototherapy for skin disease treatment and skin beauty is performed through light irradiation using lasers, lamps, or LEDs. Recently, various small cosmetic treatments are used not only in medical institutions such as hospitals, but also for simple skin care and/or skin disease treatment at home. Devices and medical devices are being developed and sold.

There are many different types of LEDs currently developed. In particular, among the various LEDs, micro LEDs and nano LEDs can achieve excellent color and high efficiency, and are eco-friendly materials, so they are used as core materials for various light sources and displays. In line with this market situation, research has recently been conducted to develop a new nanorod LED structure or a nanocable LED with a shell coating using a new manufacturing process. In addition, research is being conducted on protective film materials to achieve high efficiency and high stability of the protective film covering the outer surface of the nanorod, as well as research and development on ligand materials that are advantageous for subsequent processes.

In line with research in the field of these materials, display TVs using red, green, and blue micro-LEDs have recently been commercialized. Displays and various light sources using micro-LEDs have the advantages of high performance characteristics, very long theoretical lifespan, and high efficiency, but since micro LEDs must be placed individually on miniaturized electrodes in a limited area, micro-LEDs must be placed on electrodes. Considering the high unit cost, high process defect rate, and low productivity of electrode assemblies that are implemented by placing them using pick place technology, due to the limitations of process technology, they are not suitable for truly high-resolution commercial displays ranging from smartphones to TVs or light sources with various sizes, shapes, and brightness. It is difficult to manufacture. In addition, it is more difficult to individually place nano-LEDs, which are implemented smaller than micro-LEDs, on electrodes using pick and place technology like micro-LEDs.

In addition, as the device is assembled lying on two different electrodes, that is, the stacking direction of each semiconductor layer in the device is parallel to the main surface of the electrode, there is a problem of poor efficiency because the area from which light is extracted is small. To explain this in detail, it is known that nanorod-type LED devices are manufactured using a top-down method by mixing LED wafers with a nanopattern process and dry etching/etching, or by growing them directly on a substrate using a bottom-up method. . These nanorod-type LEDs have a narrow emission area because the long axis of the LED coincides with the stacking direction of each layer in the p-GaN/InGaN multiple quantum well (MQW)/n-GaN stacked structure. Therefore, surface defects have a significant impact on reducing efficiency, and it is difficult to optimize the sperm-hole recombination speed, so there is a problem that the luminous efficiency is significantly lower than that of the original wafer.

Furthermore, in order to emit light from a nanorod-type LED device, two different electrodes must be formed on the same plane, making electrode design difficult.

Korean Patent Publication No. 10-1163646 (announcement date: July 2, 2012)

The present invention is intended to apply ultra-small LED assemblies not only to display devices and lighting devices, but also to cosmetic devices for skin improvement or medical devices for improving and treating skin diseases. It is a flexible skin patch equipped with an ultra-small LED assembly that is attached directly to the skin and has a specific wavelength. The aim is to provide an ultra-small LED flexible skin patch that can improve and treat skin conditions and skin diseases by emitting light and a method of manufacturing the same.

The ultra-small-LED flexible skin patch of the present invention for solving the above-mentioned problems includes an LED electrode assembly including a plurality of ultra-small LED elements that emit UV with a wavelength of 200 to 400 nm, wherein the ultra-small LED elements are 1 electrode layer; a first conductive semiconductor layer formed on the first electrode layer; an active layer formed on the first conductive semiconductor layer; a second conductive semiconductor layer formed on the active layer; and a second electrode layer formed on the second conductive semiconductor layer.

As a preferred embodiment of the present invention, the ultra-small LED device includes an ultra-small LED device that emits UVC with a wavelength of 200 to 280 nm, an ultra-small LED device that emits UVB with a wavelength of 280 to 320 nm, and UVA with a wavelength of 320 to 400 nm. It may include one or more types selected from ultra-small LED elements that emit light.

As a preferred embodiment of the present invention, the ultra-small LED device may include at least one of an insulating film and a protective film on its outer surface.

In a preferred embodiment of the present invention, the insulating film is a film that covers at least the entire outer surface of the active layer portion to prevent an electrical short circuit caused by contact between the active layer and the electrode line of the ultra-small LED device.

In a preferred embodiment of the present invention, the protective film may include at least one of a hole pushing film and an electronic pushing film.

In a preferred embodiment of the present invention, the hole pushing film surrounds the exposed outer surface of the second conductive semiconductor layer, or the exposed outer surface of the second conductive semiconductor layer and the exposed outer surface of at least a portion of the active layer. It may be a film for moving holes on the surface toward the center.

In a preferred embodiment of the present invention, the electron pushing film may be a film that surrounds the exposed outer surface of the first conductive semiconductor layer and moves electrons on the exposed outer surface toward the center.

In a preferred embodiment of the present invention, the ultra-small LED device includes both the hole pushing film and the electronic pushing film, and the electronic pushing film surrounds the sides of the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer. It may also be provided as an outermost film.

_{As a preferred embodiment} of _{the present invention , the} hole _pushing film _{is AlN 2} , ZnS, Ta ₂ O ₅ and n-MoS ₂ and may include one or more selected from among.

As a preferred embodiment of the present invention, the electronic pushing film includes at least one selected from Al ₂ O ₃ , HfO ₂ , SiN _x , SiO ₂ , ZrO ₂ , Sc ₂ O ₃ , AlN _x and Ga ₂ O ₃ can do.

In a preferred embodiment of the present invention, the ultra-small LED device may further include a hydrophobic coating on the outer surface of at least one of the insulating film and the protective coating to prevent agglomeration between the ultra-small LED devices.

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

As a preferred embodiment of the present invention, the LED electrode assembly includes: a flexible substrate; an electrode line including a first electrode formed on the flexible substrate and a second electrode formed on the same plane and spaced apart from the first electrode; and the plurality of ultra-small LED elements simultaneously connected to the first electrode and the second electrode, wherein the width and length of the first electrode (X), the width and length of the two electrodes (Y), the first electrode and the second electrode The spacing distance (Z) and the length (H) of the ultra-small LED element may satisfy the following relational equation 1.

[Relationship 1]

0.5Z ≤ H <

In a preferred embodiment of the present invention, the first conductive semiconductor layer of the ultra-small LED device may be an n-type III-nitride semiconductor layer, and the second conductive semiconductor layer may be a p-type III-nitride semiconductor layer.

As a preferred embodiment of the present invention, a substrate including a skin adhesive layer including an adhesive pad or an adhesive film; and the LED electrode assembly provided on the substrate, wherein the substrate and/or the skin adhesive layer may be transparent.

In a preferred embodiment of the present invention, the skin adhesive layer and/or the substrate may have a light transmittance of 90% or more.

In a preferred embodiment of the present invention, the LED electrode assembly is encapsulated with an encapsulation material, and each of the first electrode and the second electrode may be a flexible electrode.

As a preferred embodiment of the present invention, the flexible skin batch of the present invention can promote vitamin D production in the skin.

As a preferred embodiment of the present invention, the flexible skin batch of the present invention can alleviate or improve skin diseases.

Another object of the present invention relates to a method of manufacturing the ultra-small LED flexible skin patch described above, which can be manufactured by combining a substrate including a skin adhesive layer with the various ultra-small LED electrode assemblies described above.

As a preferred embodiment of the present invention, the ultra-small LED electrode assembly includes (1) a flexible substrate, a first electrode formed on the flexible substrate, and a second electrode formed spaced apart from the first electrode on the same plane. Injecting a solution containing a plurality of ultra-small LED elements into the electrode line; and (2) self-aligning the plurality of ultra-small LED elements by applying power to the electrode line in order to simultaneously connect the plurality of ultra-small LED elements to the first electrode and the second electrode. It can be manufactured.

According to a preferred embodiment of the present invention, the ultra-small LED device may be manufactured by forming at least one of an insulating film and a protective film on the outer surface.

According to a preferred embodiment of the present invention, the ultra-small LED device may be manufactured by further forming a hydrophobic film on the outer surface of at least one of the insulating film and the protective film to prevent agglomeration between the ultra-small LED elements. .

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

According to another preferred embodiment of the present invention, step (1) includes 1-1) a flexible substrate, a first electrode formed on the flexible substrate, and a second electrode formed spaced apart on the same plane as the first electrode. manufacturing an electrode line including; 1-2) forming an insulating barrier surrounding the electrode line area on which the ultra-small LED element is mounted on the flexible substrate; and 1-3) injecting a solution containing a plurality of ultra-small LED elements into the electrode line area surrounded by the insulating partition wall; wherein the vertical distance from the flexible substrate to the top of the insulating partition wall may be 0.1 to 100㎛. .

According to another preferred embodiment of the present invention, the voltage of the power source applied in 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, the number of ultra-small LED elements simultaneously connected to the first electrode and the second electrode in step (2) is 100 × 100㎛ ² There may be 2 to 100,000 per unit.

According to another preferred embodiment of the present invention, after step (2), (3) forming a metal ohmic layer at the connection portion of the first and second electrodes and the ultra-small LED device may be further included.

According to a preferred embodiment of the present invention, the ultra-small LED electrode assembly further includes an insulating barrier wall surrounding an electrode line area where the ultra-small LED elements are connected, the insulating barrier wall is formed on a flexible substrate, and is insulated from the flexible substrate. The vertical distance to the top of the partition may be 0.1 to 100㎛.

Below, the terms used in the present invention are defined.

In the description of the embodiment according to the present invention, each layer, region, pattern or substrate, and the "on", "top", "top", "under", and "bottom" of each layer, region, and pattern. In the case where it is described as being formed in ", "below", "on", "top", "above", "under", "lower", "below" means "directly" and " Includes all meanings of “indirectly.”

In the description of the embodiment according to the present invention, “first electrode” and “second electrode” may be further included depending on the electrode area on which the ultra-small LED can be substantially mounted or the method of arranging the electrode on the flexible substrate along with the area. Includes all electrode areas. However, the ultra-small LED electrode assembly of the present invention refers to an electrode area where ultra-small LEDs can be substantially mounted.

In the description of the embodiment according to the present invention, "unit electrode" refers to an array area where two electrodes that can independently drive ultra-small LED elements are arranged, and unit electrode area refers to the area of the array area.

In the description of the embodiment according to the present invention, “connection” means that the ultra-small LED element is mounted on two different electrodes (eg, a first electrode and a second electrode). In addition, “electrically connected” means a state in which the ultra-small LED element can emit light when the ultra-small LED element is mounted on two different electrodes and power is applied to the electrode line.

The ultra-small LED device applied to the LED flexible skin patch of the present invention and the LED electrode assembly using the same are advantageous in achieving high brightness and light efficiency by increasing the light emitting area of the device compared to the electrode assembly using the conventional rod-type LED device. And, among these ultra-small LED elements, the LED flexible skin patch of the present invention using an ultra-small LED element with a specific emission wavelength range can be thinned and has excellent luminous efficiency compared to the conventional skin adhesive skin patch, so it can be used in a localized area of the skin. It is possible to provide a flexible skin patch that is excellent in promoting vitamin D production, has excellent effects in improving or treating local skin psoriasis, fungi, fungal tumors and eczema, and has excellent virus killing effects, and is easily attachable and detachable.

1 is a perspective view showing the steps of manufacturing an ultra-small LED electrode assembly according to a first preferred embodiment of the present invention.
Figure 2 is a perspective view showing the manufacturing process of an electrode line according to a preferred embodiment of the present invention.
Figure 3 is a perspective view of an electrode line including a first electrode and a second electrode formed on a flexible substrate according to a preferred embodiment of the present invention.
Figure 4 is a plan view of an electrode line including a first electrode and a second electrode formed on a flexible substrate according to a preferred embodiment of the present invention.
Figure 5 is a perspective view of an electrode line including a first electrode and a second electrode formed on a flexible substrate according to a preferred embodiment of the present invention.
Figure 6 is a perspective view of an ultra-small LED device according to a preferred embodiment of the present invention.
Figure 7 is a vertical cross-sectional view of a conventional ultra-small LED electrode assembly.
Figure 8 is a plan view and a vertical cross-sectional view of an ultra-small LED element connected to a first electrode and a second electrode according to a preferred embodiment of the present invention.
Figure 9 is a perspective view showing a manufacturing process for forming an insulating partition on a flexible substrate according to a preferred embodiment of the present invention.
Figure 10 is a perspective view of the manufacturing process of the ultra-small LED electrode assembly according to the first preferred embodiment of the present invention.
Figure 11 is a perspective view showing the steps of manufacturing an ultra-small LED electrode assembly according to a second preferred embodiment of the present invention.
Figure 12 is a perspective view and a partially enlarged view of an ultra-small LED electrode assembly according to a preferred embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. The present invention may be implemented in many different forms and is not limited to the embodiments described herein.

The ultra-small-LED flexible skin patch of the present invention includes an LED electrode assembly incorporating ultra-small LED elements.

The ultra-small LED device may include an LED device that emits UV light with a wavelength of 200 to 400 nm. Preferably, the ultra-small LED device includes an LED device that emits UV light with a wavelength of 200 to 280 nm, and an LED device that emits UV light with a wavelength of 280 to 320 nm. It may include at least one type selected from among LED elements that emit UVB and LED elements that emit UVA at a wavelength of 320 to 400 nm, and more preferably include an LED element that emits UVB at a wavelength of 280 to 320 nm. You can.

The LED electrode assembly may be formed (or provided) on a substrate.

The substrate may include a skin adhesive layer including an adhesive pad or adhesive film. At this time, the adhesive pad also includes the adhesive sheet.

The substrate may be the skin adhesive layer itself, or may be a transparent adhesive layer formed on one side of the transparent substrate.

One side of the skin adhesive layer may further include a protective film (or release film).

The skin adhesive layer and/or the substrate are made of a transparent material, and the skin adhesive layer and/or the substrate may have a light transmittance of 90% or more, preferably a light transmittance of 95% or more, more preferably 98%. It could be more than that.

The substrate is preferably a flexible substrate.

The LED electrode assembly includes a flexible substrate; an electrode line including a first electrode formed on the flexible substrate and a second electrode formed on the same plane and spaced apart from the first electrode; and a plurality of ultra-small LED elements simultaneously connected to the first electrode and the second electrode.

Also, the first electrode and/or the second electrode may be a flexible electrode.

Additionally, the LED electrode assembly may be encapsulated with an encapsulating material.

The manufacturing method of the ultra-small LED electrode assembly applied to the flexible skin patch of the present invention will be described in detail as follows.

The first embodiment of the ultra-small LED electrode assembly includes (1) a flexible substrate, a first electrode formed on the flexible substrate, and a plurality of electrode lines including a second electrode formed spaced apart on the same plane as the first electrode. Injecting a solution containing ultra-small LED elements; and (2) self-aligning the plurality of ultra-small LED elements by applying power to the electrode line in order to simultaneously connect the plurality of ultra-small LED elements to the first electrode and the second electrode. Manufactures LED electrode assemblies.

And, the width length of the first electrode (X), the width length of the two electrodes (Y), the gap distance between the first electrode and the second electrode adjacent to the first electrode (Z), and the length of the ultra-small LED element (H) satisfies relational expression 1 below.

[Relationship 1]

0.5Z ≤ H <

Through this, when conventional ultra-small LED elements are erected and combined with electrodes in a three-dimensional shape, it is possible to overcome the problem of not being able to stand the ultra-small LED elements upright and the difficulty of combining the ultra-small LED elements with different ultra-small electrodes in one-to-one correspondence. You can. In addition, by aligning the ultra-small LED element to the target electrode area, it is possible to connect the ultra-small LED element to the electrode without defects such as electrical short circuit. Furthermore, due to the directionality of the ultra-small LED element connected to the electrode, the amount of photons emitted into the air among the photons generated in the active layer increases, thereby greatly improving the light extraction efficiency of the ultra-small LED electrode assembly.

Specifically, Figure 1 is a perspective view showing the steps of manufacturing an ultra-small LED electrode assembly according to a first preferred embodiment of the present invention. Figure 1a shows a first electrode 110 formed on a flexible substrate 100, and the first electrode. It shows a solution (LED device 120, solvent 140) containing a second electrode 130 and a plurality of ultra-small LED devices spaced apart from each other on the same plane.

First, the manufacturing method of the electrode line for ultra-small LED will be described. Specifically, Figure 2 is a perspective view showing the manufacturing process of an electrode line formed on a flexible substrate according to a preferred embodiment of the present invention. However, the manufacturing process of the electrode line for ultra-small LEDs is not limited to the manufacturing process described later.

First, Figure 2a shows a flexible substrate 100 on which electrode lines are formed. Preferably, any one of a glass substrate, a quartz substrate, a sapphire substrate, a plastic substrate, and a bendable flexible polymer film can be used. Even more preferably, the substrate may be transparent. However, it is not limited to the above types, and any type of flexible substrate on which electrodes can be formed can be used.

The area of the flexible substrate is not limited, and the area of the first electrode to be formed on the flexible substrate, the area of the second electrode, the size of the ultra-small LED elements connected to the first electrode and the second electrode, and the number of ultra-small LED elements connected to the flexible substrate. It may change taking into account. Preferably, the thickness of the flexible substrate may be 100㎛ to 1 mm, but is not limited thereto.

Afterwards, photo resist (PR, photo resist) 101 can be coated on the flexible substrate 100 as shown in FIG. 2B. The photoresist may be a photoresist commonly used in the art. The method of coating the photoresist on the flexible substrate 100 may be any one of spin coating, spray coating, and screen printing, preferably spin coating, but is not limited thereto, and specific methods are known in the art. It may be done by a known method. The thickness of the photoresist 101 to be coated may be 0.1 to 10 ㎛. However, the thickness of the coated photoresist 101 may change in consideration of the thickness of the electrode to be subsequently deposited on the flexible substrate.

After forming the photoresist 101 layer on the flexible substrate 100 as described above, the first electrode and the second electrode are spaced apart in an alternating arrangement on the same plane, corresponding to the electrode line (see FIG. 3). The mask 102 on which the patterns 102a and 102b are drawn is placed on the photoresist 101 layer as shown in FIG. 2C, and ultraviolet rays can be exposed from the top of the mask 103.

Thereafter, the unexposed photoresist layer can be removed by immersing it in a typical photoresist solvent, and through this, the exposed portion of the photoresist layer where the electrode line as shown in FIG. 2D will be formed can be removed. The width of the pattern 102a corresponding to the first electrode line corresponding to the electrode line for the ultra-small LED may be 100 nm to 50 ㎛, and the width of the pattern 102b corresponding to the second electrode line may be 100 nm to 50 ㎛. However, it is not limited to the above description.

Thereafter, the electrode forming material 103 can be deposited on the area where the photoresist layer was removed in the shape of the electrode line mask 102, as shown in FIG. 2E. In the case of the first electrode, the electrode forming material is one or more metal materials selected from the group consisting of aluminum, titanium, indium, gold, and silver, or ITO (Indum Tin Oxide), ZnO:Al, and CNT-conductive polymer (polmer) composite. It may be any one or more transparent materials selected from the group consisting of. When two or more types of electrode forming materials are used, the first electrode may preferably have a structure in which two or more types of materials are stacked. More preferably, the first electrode may be an electrode in which two types of materials such as titanium and gold are stacked. However, the first electrode is not limited to the above description.

Materials forming the first electrode and the second electrode may be the same or different. The electrode forming material may be deposited by any one of methods such as thermal evaporation, e-beam deposition, sputtering deposition, and screen printing, and is preferably thermal evaporation, but is not limited thereto.

After depositing the electrode forming material 103, a photoresist of any one of acetone, N-methyl-2-pyrrolidone (NMP), and dimethyl sulfoxide (DMSO) is applied as shown in FIG. 2f. When the photoresist layer 101 coated on the flexible substrate 100 is removed using a remover, electrode lines 103a (110 in FIG. 1) and 103b (130 in FIG. 1) deposited on the flexible substrate 100 are manufactured. can do.

In the electrode line of the present invention manufactured through the above-described method, the unit electrode area, that is, the area of the array area where two electrodes that can be independently driven by arranging ultra-small LED elements, is preferably 1㎛ ² to 100 cm ² and, more preferably, may be 10㎛ ² to 100 mm ² , but the area of the unit electrode is not limited to the above area. Additionally, the electrode line may include one or more 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 an ultra-small LED element. Through this, an ultra-small LED element can be placed between the first and second electrodes in a lying position, sandwiched between the two electrodes, or connected across the two electrodes.

On the other hand, the applicable electrode line of the present invention is a second electrode formed spaced apart on the same plane as the first electrode, which will be described later, and can be applied as long as it can mount an ultra-small LED. The first electrode and the first electrode spaced apart on the same plane are applicable. 2 The specific arrangement of the electrodes may vary depending on the purpose.

Specifically, Figure 3 is a perspective view of electrode lines for a first electrode and a second electrode formed on a flexible substrate according to a preferred embodiment of the present invention. The first electrode 213 may be formed on the flexible substrate 200. . The meaning of “on the flexible substrate” means that at least one of the first electrode and the second electrode can be formed directly on the surface of the flexible substrate or spaced apart from the upper part of the flexible substrate.

More specifically, in FIG. 3, both the first electrodes 213 and 214 and the second electrodes 233 and 234 are formed directly on the surface of the flexible substrate 200, and the first electrode 214 and the second electrode 234 These can be arranged alternately to form electrode lines 244 spaced apart on the same plane.

Figure 4 is a plan view of electrode lines for the first and second electrodes formed on a flexible substrate according to a preferred embodiment of the present invention, and both the first electrodes 212 and 215 and the second electrodes 232 and 235 are flexible. While being formed directly on the surface of the substrate 201, the first electrode 215 and the second electrode 235 may be arranged in a swirl to form electrode lines 245 spaced apart from each other on the same plane.

When the electrode lines are configured in an alternating arrangement or a swirl arrangement as described above, the driving area of the unit electrode that can be driven independently can be increased by arranging the ultra-small LEDs included in the flexible substrates 200 and 201 of a limited area at once. This makes it possible to increase the number of ultra-small LEDs mounted on a unit electrode. This increases the intensity of LED light emission per unit area, so it can be used in various photovoltaic device applications that require high brightness per unit area.

Meanwhile, Figures 3 and 4 are a preferred embodiment, but are not limited to this and can be implemented by various modifications to any imaginable arrangement of structures in which two electrodes are spaced at a constant distance.

In addition, unlike the electrode line according to a preferred embodiment of the present invention shown in FIG. 3, according to another preferred embodiment of the present invention, the second electrode may be formed to be spaced apart from the upper part of the flexible substrate.

Specifically, Figure 5 is a perspective view of electrode lines for a first electrode and a second electrode formed on a flexible substrate according to a preferred embodiment of the present invention, in which the first electrode 211 is formed directly on the surface of the flexible substrate 202. However, the second electrodes 231 and 236 are formed to be spaced apart from each other on the flexible substrate 202, and the first 'electrode 216 is connected to the first electrode 211 through a connection electrode, and the flexible substrate 202 It is formed to be spaced apart from the first electrode 211 at the top, and the first' electrode 216 and the second electrode 236 are arranged alternately on the same plane to form a spaced apart electrode line 246. You can.

Hereinafter, the description will focus on the shape in which the first electrode and the second electrode are arranged alternately on the same plane. However, the first electrode and the second electrode may be formed directly on the surface of the flexible substrate or spaced apart from the surface of the flexible substrate, and the first electrode and the second electrode may not be on the same plane.

Next, a solution containing ultra-small LED elements (120 and 140 in FIG. 1A) will be described.

The solution containing the ultra-small LED elements (120 and 140 in FIG. 1A) can be prepared by mixing a plurality of ultra-small LED elements 120 with the solvent 140. The solution may be in the form of ink or paste. Preferably, the solvent 140 may be one or more selected from the group consisting of acetone, water, alcohol, and toluene, and more preferably, it may be acetone. However, the type of solvent 140 is not limited to the above description, and any solvent 140 that can evaporate well without having a physical or chemical effect on the ultra-small LED device 120 can be used without limitation. .

Preferably, the ultra-small LED device may be included in an amount of 0.001 to 100 parts by weight based on 100 parts by weight of the solvent. If it is contained in less than 0.001 parts by weight, it may be difficult for the ultra-small LED electrode assembly to function normally due to the small number of ultra-small LED elements connected to the electrode. To overcome this, there may be a problem that the solution must be added dropwise several times. 100 parts by weight If it exceeds this, there may be a problem in that the alignment of individual ultra-small LED elements may be disturbed.

The ultra-small LED device will be described.

The length of the ultra-small LED device used in the present invention may be 100 nm to 10 μm, and more preferably 500 nm to 5 μm. If the length of an ultra-small LED device is less than 100 nm, it is difficult to manufacture a highly efficient LED device, and if it exceeds 10 μm, the luminous efficiency of the LED device may be reduced. The shape of the ultra-small LED device may be of various shapes, such as a cylinder or a rectangular parallelepiped, and is preferably cylindrical, but is not limited to the above description.

Hereinafter, in the description of the ultra-small LED device, 'top', 'bottom', 'top', 'bottom', 'top', and 'bottom' refer to the vertical up and down directions based on each layer included in the ultra-small LED device. means.

The ultra-small LED device includes a first electrode layer; a first conductive semiconductor layer formed on the first electrode layer; an active layer formed on the first conductive semiconductor layer; a second conductive semiconductor layer formed on the active layer; and a second electrode layer formed on the second conductive semiconductor layer.

Specifically, Figure 6 is a perspective view showing an embodiment of the ultra-small LED device included in the present invention, showing the active layer 22 formed on the first conductive semiconductor layer 21 formed on the first electrode layer 11, and the active layer ( It includes a second conductive semiconductor layer 23 formed on 22) and a second electrode layer 12 on the second conductive semiconductor layer 23.

First, the first electrode layer 11 will be described.

The first electrode layer 11 can be made of metal or metal oxide used as an electrode in a typical LED device, preferably chromium (Cr), titanium (Ti), aluminum (Al), gold (Au), or nickel ( Ni), ITO, and their oxides or alloys can be used alone or in combination, but are not limited thereto. Preferably, the thickness of the first electrode layer may be 1 to 100 nm, but is not limited thereto. When the first electrode layer is included, there is an advantage that the connection area between the first semiconductor layer and the electrode line can be contacted at a temperature lower than that required in the process of forming a metal ohmic layer.

Next, the first conductive semiconductor layer 21 formed on the first electrode layer 11 will be described. The first conductive semiconductor layer 21 may include, for example, an n-type semiconductor layer. When the ultra-small LED device is a blue light-emitting device, the n-type semiconductor layer has a composition formula of In _x A _y Ga _1-xy N (0≤x≤1, 0 ≤y≤1, 0≤x+y≤1) One or more semiconductor materials having a , such as InAlGaN, GaN, AlGaN, InGaN, AlN, InN, etc., may be selected, and may be doped with a first conductive dopant (e.g., Si, Ge, Sn, etc.). Preferably, the thickness of the first conductive semiconductor layer 21 may be 500 nm to 5㎛, 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 group III-V semiconductor materials as the n-type semiconductor layer when the light emission color is 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 is formed on the first conductive semiconductor layer 21 and may be formed in a single or multiple quantum well structure. A clad layer (not shown) doped with a conductive dopant may be formed above and/or below the active layer 22, and the clad layer doped with a conductive dopant may be implemented as an AlGaN layer or an InAlGaN layer. Of course, other materials such as AlGaN and AlInGaN can also be used as the active layer 12. When an electric field is applied to this active layer 22, light is generated by the combination 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 can be formed in various positions depending on the type of LED. The ultra-small LED emits light in the range of 200 to 400 nm wavelength, preferably 280 to 320 nm wavelength, and there is no limitation in using other types of group III-V semiconductor materials as the active layer.

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

When the ultra-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 implemented with at least one p-type semiconductor layer. The _p -type semiconductor layer may _be made of a _{semiconductor} material with a composition formula of In Any one or more of GaN, AlGaN, InGaN, AlN, InN, etc. may be selected, and a second conductive dopant (eg, Mg) may be doped. Here, the light emitting structure includes the first conductive semiconductor layer 21, the active layer 22, and the second conductive semiconductor layer 23 as minimum components, and other phosphor layers above and below each layer, It may further include 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 It may be, but is not limited to this. There is no limitation in using other types of group III-V semiconductor materials as the p-type semiconductor layer in the range in which the ultra-small LED emits light at a wavelength of 200 to 400 nm, preferably in the range of 280 to 320 nm.

Next, the second electrode layer 12 formed on the second conductive semiconductor layer 23 will be described.

The second electrode layer 12 can be made of metal or metal oxide used as an electrode in a typical LED device, preferably chromium (Cr), titanium (Ti), aluminum (Al), gold (Au), or nickel. (Ni), ITO, and their oxides or alloys can be used alone or in combination, but are not limited thereto. Preferably, the thickness of the second electrode layer may be 1 to 100 nm, but is not limited thereto. When the second electrode layer is included, there is an advantage that the connection area between the second semiconductor layer and the electrode line can be contacted at a temperature lower than that required in the process of forming a metal ohmic layer.

Meanwhile, the ultra-small LED element included in the ultra-small LED electrode assembly according to the present invention includes an insulating film 30; and protective film (35); It may include at least one of the coatings.

The insulating film 30 is intended to prevent short circuits caused by contact between the active layer 22 of the ultra-small LED device and the electrode line included in the ultra-small LED electrode assembly, and is provided on the outer surface of the ultra-small LED device at least on the outer surface of the active layer portion. It can be formed to cover the entire thing.

In addition, the insulating film 30 includes at least one of the first semiconductor layer 21 and the second semiconductor layer 23 in order to simultaneously prevent durability deterioration of the ultra-small LED device through electrical short circuit and damage to the external surface of the semiconductor layer. It can also be formed on the exterior surface.

Specifically, in FIG. 6A, 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 film 30 serves to prevent electrical short-circuiting that occurs when the active layer included in the ultra-small LED device contacts the electrode. In addition, the insulating film 30 protects the external surface including the active layer of the ultra-small LED device, thereby preventing defects on the external surface of the device and preventing a decrease in luminous efficiency.

If each ultra-small LED element can be individually placed and connected between two different electrodes, electrical short circuits that occur when the active layer touches the electrodes can be prevented. However, it is physically difficult to mount nanoscale ultra-small LED elements on electrodes one by one. Accordingly, when power is applied as in the present invention to self-align an ultra-small LED element between two different electrodes, the ultra-small LED element changes position, such as moving and aligning between the two different electrodes, and in this process, the ultra-small LED element Since the outer surface of the active layer 22 of the device may contact the electrode line, electrical short circuits may frequently occur.

On the other hand, when an ultra-small LED device is erected on an electrode, the problem of electrical short circuit caused by contact between the active layer and the electrode line may not occur. In other words, the active layer and the electrode line can only come into contact when the ultra-small LED element cannot be erected on the electrode and the LED element is lying on the electrode. In this case, the problem of not being able to connect the ultra-small LED element to two different electrodes arises. However, the problem of electrical short circuit may not occur.

Specifically, Figure 7 is a vertical cross-sectional view of a conventional ultra-small electrode assembly, in which the first semiconductor layer 71a of the first ultra-small LED element 71 is connected to the first electrode line 61, and the second semiconductor layer ( It can be confirmed that 71c) is connected to the second electrode line 62, and that the first ultra-small LED element 71 is connected upright to the two electrodes 61 and 62 located vertically. In the electrode assembly shown in Figure 7, if the first ultra-small LED device 71 is connected to two electrodes at the same time, the active layer 71b of the device is unlikely to contact any one of the two different electrodes 61 and 62, so the active layer Electrical short circuit may not occur due to contact between (71b) and the electrodes 61 and 62.

In contrast, in FIG. 7, the second ultra-small LED element 72 is lying on the first electrode 61, and in this case, the active layer 72b of the second ultra-small LED element 72 is in contact with the first electrode 61. . However, in this case, there is only a problem that the second ultra-small LED element is not connected to the first electrode 61 and the second electrode 62, and no problem of electrical short circuit occurs. Accordingly, if an insulating film 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 as shown in FIG. 7, The insulating film has only the purpose and effect of reducing luminous efficiency by preventing damage to the external surface of the ultra-small LED device.

However, in the present invention, unlike the conventional ultra-small electrode assembly as shown in FIG. 7, two different electrodes are formed spaced apart on the same plane (see FIG. 3), and the ultra-small LED element is laid and connected parallel to the same plane on which the two electrodes are formed. Therefore, an electrical short circuit problem inevitably occurs due to contact between the active layer of the ultra-small LED device and the electrode, which did not occur in the conventional ultra-small electrode assembly. Therefore, to prevent this, ultra-small LED devices require an insulating film on the outer surface of the device that covers at least the entire outer surface of the active layer.

Furthermore, in an ultra-small LED device having a structure in which the first semiconductor layer, the active layer, and the second semiconductor layer are sequentially vertically arranged, such as the ultra-small LED device included in the ultra-small electrode assembly according to the present invention, the active layer is inevitably exposed to the outside. . In addition, in an LED device with this structure, the position of the active layer is not located only at the center of the device in the longitudinal direction, but may be formed biased toward a specific semiconductor layer, which can further increase the possibility of contact between the electrode and the active layer. Accordingly, the insulating film is necessary to achieve the purpose 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.

Figure 8 shows 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. Specifically, as shown in the cross-sectional view A-A in FIG. 8, the active layer 121b of the first ultra-small LED elements 121a, 121b, and 121c is not located in the center of the ultra-small LED element 121 but is tilted far to the left. In this case, the active layer 121b ) may contact the electrode 131, causing an electrical short circuit, which may cause defects in the ultra-small LED electrode assembly. In order to solve the above problems, the ultra-small LED device included in the present invention is coated with an insulating film on the outer surface including the active layer portion, and the active layer (121b) like the first ultra-small LED device 121 in FIG. 8 due to the insulating film. Even if it is across this electrode, a short circuit may not occur.

The insulating film 30 is preferably made of 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 It may contain one or more of titanium dioxide (TiO ₂ ), and more preferably, may be made of the above components, but may be transparent, but is not limited thereto. In the case of a transparent insulating film, a decrease in luminous efficiency that may occur can be minimized by coating the insulating film at the same time as the insulating film 30 described above.

Meanwhile, according to a preferred embodiment of the present invention, the insulating film 30 may not be coated on any one or more of the first electrode layer 11 and the second electrode layer 12 of the ultra-small LED device, More preferably, both electrode layers 11 and 12 may not be coated with an insulating film. This means that there must be an electrical connection between the two electrode layers (11, 12) and the other electrodes, but if the two electrode layers (11, 12) are coated with an insulating film (30), the electrical connection may be interrupted, preventing the ultra-small LED from emitting light. There is a problem that the light itself may not be emitted because it is reduced or not electrically connected. However, if there is an electrical connection between the two electrode layers (11, 12) of the ultra-small LED device and the other electrodes, there may be no problem with the light emission of the ultra-small LED device, and all parts except the ends of the two electrode layers (11, 12) of the ultra-small LED device The remaining electrode layers 11 and 12 may include an insulating film 30.

Meanwhile, the protective film 35 functions to protect the surfaces of the first conductive semiconductor layer, the active layer, and/or the second conductive semiconductor layer, and serves to increase the light extraction efficiency of the ultra-small LED device.

The protective film (35) surrounds the exposed side of the second conductive semiconductor layer, or the exposed side of the second conductive semiconductor layer and at least a portion of the active layer to move holes on the exposed side surface toward the center. Hole pushing film (31); and an electron pushing film 32 surrounding the exposed side of the first conductive semiconductor layer to move electrons on the exposed side surface toward the center; It may include at least one of the coatings.

In addition, the ultra-small LED device includes both the hole pushing film and the electronic pushing film, and the electronic pushing film may be provided as an outermost film surrounding the sides of the first conductive semiconductor layer, the active layer, and the second conductive semiconductor layer. .

_{In addition , the hole pushing film is AlN _ _ _ _ _} It may include one or more selected from ₅ and n-MoS ₂ .

Additionally, the electronic pushing film may include one or more selected from Al ₂ O ₃ , HfO ₂ , SiN _x , SiO ₂ , ZrO ₂ , Sc ₂ O ₃ , AlN _x and Ga ₂ O ₃ .

The protective film 35 is, for example, silicon nitride (Si ₃ N ₄ ), silicon dioxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), zirconium oxide (ZrO ₂ ), and yttrium oxide ( Y ₂ O ₃ ), titanium dioxide (TiO ₂ ), aluminum nitride (AlN), and gallium nitride (GaN). The thickness of the protective film 35 may be 5 nm to 100 nm, more preferably 30 nm to 100 nm.

Meanwhile, as shown in Figure 6b, the ultra-small LED device according to an embodiment of the present invention has an exposed side of the second conductive semiconductor layer, or a second conductive semiconductor, in order to have improved luminous efficiency in addition to the protection function as a protective film. A hole pushing film 31 surrounds the exposed side of the layer and the exposed side of at least a portion of the active layer to move holes on the exposed side surface toward the center, and surrounds and exposes the exposed side of the first conductive semiconductor layer. A protective film 35 composed of an electron pushing film 32 may be provided to move electrons from the side surface toward the center.

Part of the charge moved from the first conductive semiconductor layer to the active layer and part of the hole moved from the second conductive semiconductor layer 23 to the active layer 22 may move along the side surface. In this case, the There is a risk that electrons or holes may be depleted due to defects, which may result in a decrease in luminous efficiency. In this case, even if a protective film is provided, there is an unavoidable problem of scratching due to defects generated on the device surface before the protective film is provided. However, when the protective film 35 is composed of the hole pushing film 31 and the electronic pushing film 32, electrons and holes are concentrated toward the center of the device and induced to move toward the active layer, so even if there are defects on the device surface before forming the protective film. There is an advantage in preventing loss of luminous efficiency due to surface defects.

In addition, as shown in FIG. 6b, when the ultra-small LED device includes both a hole pushing film 31 and an electronic pushing film 32, the hole pushing film 31 surrounds the sides of the second conductive semiconductor layer and the active layer. , and the electronic pushing film 32 may be provided as an outermost film surrounding the side surface of the first conductive semiconductor layer.

In addition, as shown in FIG. 6C, when the ultra-small LED device includes both a hole pushing film 31 and an electronic pushing film 32, the hole pushing film 31 surrounds the second conductive semiconductor layer and acts as an electronic pushing film. The coating 32 may be provided as an outermost coating surrounding the side surface of the first conductive semiconductor layer. Additionally, the active layer may not have a protective film or an insulating film formed thereon.

In addition, as shown in FIG. 6D, when the ultra-small LED device includes both an insulating film and a protective film, the hole pushing film 31 surrounds the second conductive semiconductor layer, and the insulating film 30 covers the side of the active layer. Surrounding, the electronic pushing film 32 may be provided as an outermost film surrounding the side of the first conductive semiconductor layer.

In addition, each of the ultra-small LED devices shown in FIGS. 6B to 6D may further have an array induction layer formed below the first electrode layer and/or above the second electrode layer (not shown).

Additionally, the hole pushing film and the electronic pushing film may each independently have a thickness of 1 to 50 nm.

According to a preferred embodiment of the present invention, the ultra-small LED device may further include a hydrophobic film 40 on the insulating film 30 and/or the protective film 35. The hydrophobic film 40 has hydrophobic properties on the surface of the ultra-small LED elements to prevent agglomeration between the ultra-small LED elements. When the ultra-small LED elements are mixed with a solvent, it minimizes agglomeration between the ultra-small LED elements to form independent ultra-small LED elements. The problem of impairing the characteristics of the LED can be eliminated, and each ultra-small LED element can be aligned more easily when power is applied to the electrode line.

A hydrophobic film 40 may be formed on the insulating film 30. In this case, the hydrophobic film that can be used can be used without limitation as long as it is formed on the insulating film and can prevent agglomeration between ultra-small LED elements. Preferably, octadecyltrichlorosilane (OTS) and fluorine are used. Self-assembled monolayers (SAMs) such as fluoroalkyltrichlorosilane and perfluoroalkyltriethoxysilane, and fluoropolymers such as Teflon and Cytop. It can be used alone or in combination, but is not limited thereto.

Meanwhile, the length of the ultra-small LED element included in the ultra-small LED electrode assembly applied to the flexible skin patch of the present invention satisfies the following relational equation 1 for electrical connection between the ultra-small LED element and two different electrodes. If not electrically connected, even if power is applied to the electrode line, the ultra-small LED element that is not electrically connected does not emit light, which may be a fatal problem in that the purpose of the present invention cannot be achieved.

[Relationship 1]

0.5Z ≤ H < , in this case, 100nm < X is the length of the first electrode width included in the electrode line, Y is the length of the second electrode width, and Z is the distance between the first electrode and the second electrode adjacent to the first electrode, H corresponds to the length of the ultra-small LED element. Here, when there are a plurality of first and second electrodes, the spacing distance (Z) between the two electrodes may be the same or different.

The portion where the ultra-small LED device is electrically connected to two different electrodes is any one or more layers of the first electrode layer and the first conductive semiconductor layer (or any one or more layers of the second conductive semiconductor layer and the second electrode layer) of the ultra-small LED device. ) can be.

If the length of an ultra-small LED element is significantly smaller than the gap between two different electrodes, it may be difficult for the ultra-small LED element to be connected to two different electrodes at the same time. Accordingly, the length (H) of the ultra-small LED device according to the present invention satisfies 0.5Z≤H in relational equation 1 above. If the length (H) of the ultra-small LED element does not satisfy 0.5Z≤H in Equation 1, the ultra-small LED element cannot be electrically connected to the first electrode and the second electrode, and either the first electrode or the second electrode There may be a problem in that the ultra-small LED element is connected only to the electrode. More preferably, as shown in FIG. 8, the second ultra-small LED element 122 can be electrically connected by being sandwiched between the electrodes between the first electrode 111 and the second electrode 131, so that the ultra-small LED element included in the present invention is It may be an LED device that satisfies Z ≤ H in Relation 1.

On the other hand, when the length (H) of the ultra-small LED element is lengthened considering the width length (X) of the first electrode, the width length (Y) of the second electrode, and the electrode spacing distance (Z) between the first and second electrodes, Parts other than both ends of the third ultra-small LED element 123 of 8 may be independently connected to the first electrode 112 and the second electrode 132. If the active layer of the third ultra-small LED device 123 is not located in the center of the device and the outer surface of the device is not coated with an insulating film that covers at least the outer surface of the active layer portion, the electrode 112 or 132 and the third ultra-small LED This may cause an electrical short circuit between the elements 123. However, the ultra-small LED device according to the present invention includes an insulating film that covers at least the entire outer surface of the active layer portion and/or a protective film that covers the outer surfaces of the first and second conductive semiconductor layers on the outer surface, so that the third ultra-small LED device in FIG. 8 Even when parts other than both ends of an ultra-small LED element, such as the LED element 123, are connected to 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 becomes longer by simultaneously considering the width length (X) of the first electrode, the width length (Y) of the second electrode, and the electrode spacing distance (Z) between the first and second electrodes. Accordingly, if H <

Specifically, in FIG. 8, the fourth ultra-small LED element 124 is simultaneously connected to the two second electrodes 132 and 133 and one first electrode 112. In this case, the length of the ultra-small LED element is This is a case where H < In these ultra-small LED devices, the outer surface of the active layer is coated with an insulating film, so the problem of electrical short circuit due to the second electrodes 132 and 133 or the first electrode 112 coming into contact with the active layer can be eliminated, but there are two As both ends of the ultra-small LED element 124 are connected to the two electrodes 132 and 133, there is no actual electrical connection, and the fourth ultra-small LED element 124 of FIG. 8 is connected to the electrode line when power is applied to the electrode line. There may be a problem in that it does not emit light.

In addition, if the length (H) of the ultra-small LED element is longer than the fourth ultra-small LED element 124, both ends of the ultra-small LED element are connected to the first electrode 111 and the second electrode 133 to be electrically connected. However, if the length of the ultra-small LED element becomes long, the luminous efficiency may decrease, so there may be a problem in that the desired ultra-small LED electrode assembly cannot be manufactured. Therefore, in order to prevent these problems, the length (H) of the ultra-small LED element must satisfy H < X + Y + 2Z in Equation 1.

However, if the active layer of the ultra-small LED device is formed biased toward a specific conductive semiconductor layer (see 125b in FIG. 8), the part of the ultra-small LED device connected to the electrode is not the electrode layer and/or the conductive semiconductor layer, but the active layer coated with an insulating film. In this case, an electrical short circuit does not occur due to the insulating film, but there may be a problem in that the ultra-small LED element may not be electrically connected to the electrode line.

Specifically, in FIG. 8, the fifth ultra-small LED element 125 is simultaneously connected to the first electrode 111 and the second electrode 131. However, looking at the cross-sectional view along B-B in FIG. 8, the portion of the fifth ultra-small LED element 125 connected to the first electrode 111 is a portion of the active layer 125c coated with an insulating film, and the first electrode layer 125a and the first conductive layer are It can be confirmed that the semiconductor layer 125b is not connected to the first electrode 111. This fifth ultra-small LED device has an insulating film coated on the outer surface of the active layer (125c), so electrical short circuit does not occur, but the first electrode layer (125a) and the first conductive semiconductor layer (125b) are connected to the first electrode (111). Because it is not connected, the ultra-small LED element 125 may have a problem in that it does not emit light when power is applied to the electrode line.

In addition, even when the length (H) of the ultra-small LED element satisfies X + Y + Z < H < There may be cases where it is not possible to implement an ultra-small LED electrode assembly. Specifically, in FIG. 8, the sixth ultra-small LED element 126 is electrically connected to the first electrode 111 and the second electrode 131, so there may be no problem in emitting light when power is applied to the electrode line, but the first electrode 111 is electrically connected to the second electrode 131. As the electrode 111 and the second electrode 131 are not mounted perpendicularly to each other and are mounted at an angle, the area of the electrode line occupied by one ultra-small LED element for mounting increases, and as a result, the ultra-small LED element with a limited area in the electrode line is installed. As the number of ultra-small LED elements that can be mounted in the LED element mounting area decreases, there may be a problem in that it may be difficult to implement an ultra-small LED electrode assembly that emits the 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 ≤ In this case, regardless of the position of the active layer coated with an insulating film in the longitudinal direction of the ultra-small LED device, an electrically connected ultra-small LED electrode assembly can be implemented without electrical short-circuiting, and the electrode line area occupied by one ultra-small LED device is reduced. The number of ultra-small LED elements that can be mounted on an electrode line with a limited area can be increased, which can be very advantageous in implementing the desired ultra-small LED electrode assembly.

Meanwhile, step (1) according to the present invention of injecting a solution containing an ultra-small LED element into an electrode line containing a first electrode and a second electrode includes 1-1) a flexible substrate, and a first electrode formed on the flexible substrate. and manufacturing an electrode line including a second electrode formed on the same plane as the first electrode and spaced apart from the first electrode. 1-2) forming an insulating barrier surrounding the electrode line area on which ultra-small LED elements can be mounted on the flexible substrate; and 1-3) injecting a solution containing a plurality of ultra-small LED elements into the electrode line area surrounded by the insulating partition wall.

First, step 1-1) may include manufacturing an electrode line including a flexible substrate, a first electrode formed on the flexible substrate, and a second electrode formed spaced apart on the same plane as the first electrode. . The specific method of forming the electrode in step 1-1) is omitted below as described above.

Next, step 1-2) may include forming an insulating barrier surrounding the electrode line area on which the ultra-small LED element can be mounted on the flexible substrate.

The insulating barrier wall prevents the solution containing the ultra-small LED elements from spreading outside the electrode line area where the ultra-small LED elements are to be mounted when the solution containing the ultra-small LED elements is injected into the electrode line in steps 1-3), which will be described later. It is responsible for ensuring that ultra-small LED elements can be placed in the desired electrode line area.

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

Specifically, Figure 9 is a schematic diagram showing a manufacturing process for forming an insulating barrier 107 on a flexible substrate 100 and an electrode line formed on the flexible substrate 100 according to a preferred embodiment of the present invention, as described above. As shown in 2f, the insulating partition wall 107 can be manufactured after manufacturing the electrode lines 103a and 103b deposited on the flexible substrate 100.

First, the insulating layer 104 can be formed on the flexible substrate 100 as shown in FIG. 9A and the electrode lines 103a and 103b formed on the flexible substrate 100, as shown in FIG. 9B. The insulating layer 104 is a layer that forms an insulating partition after going through a process to be described later. The material of the insulating layer 104 may be an insulating material commonly used in the industry, and is preferably silicon dioxide (SiO ₂ ), 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 ) among inorganic insulators and various transparent polymer insulators. There may be more than one. When coating the insulating layer 104 with an inorganic insulating layer on the flexible substrate 100 and the electrode lines 103a and 103b formed on the flexible substrate 100, the method is chemical vapor deposition, atomic layer deposition, or vacuum. It may be performed by any one of (vacuum) deposition, e-beam deposition, and spin coating, and preferably chemical vapor deposition, but is not limited thereto. In addition, the method of coating the polymer insulating layer may be any one of methods such as spin coating, spray coating, and screen printing, preferably spin coating, but is not limited thereto, and the specific coating method is as follows. It may be done by a method known in the industry. The thickness of the insulating layer 104 to be coated is at least 1/2 of the radius of the ultra-small LED element so that the ultra-small LED element does not overflow and does not affect the post-process, and is generally a thickness that may not affect the post-process, and is preferably 0.1 to 0.1. It may be 100㎛, and more preferably 0.3 to 10㎛. If the above range is not met, there is a problem that affects post-processing and makes it difficult to manufacture products containing ultra-small LED electrode assemblies. If the thickness of the insulating layer is too thin compared to the diameter of the ultra-small LED element, the ultra-small LED electrode assembly can be used through the insulating barrier. The effect of preventing the spread of LED elements may not be achieved, and there may be a problem in which the solution containing ultra-small LED elements overflows outside the insulating barrier.

Afterwards, a photo resist (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 the specific method is known to those skilled in the art. It may be done 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 during etching, and accordingly, the thickness of the photoresist 105 may be 1 to 20㎛. However, the thickness of the coated photoresist 105 may be changed depending on the subsequent purpose.

After forming the photoresist 105 layer 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 105 layer as shown in FIG. 9C, and the mask (106) Ultraviolet rays can be exposed from the top.

Thereafter, the exposed photoresist layer can be removed by immersing it in a typical photoresist solvent, and through this, the exposed photoresist layer portion corresponding to the area of the electrode line where the ultra-small LED device will be mounted is removed, as shown in Figure 9d. can do.

Next, a step of removing the exposed portion of the insulating layer through etching may be performed in the area where the insulating layer is exposed by removing the photoresist layer. The etching may be performed through wet etching or dry etching, and is preferably performed through dry etching. The specific etching method may be a method known in the art. The dry etching may be specifically performed by any one or more 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 flexible substrate 100 and the electrode lines 103a and 103b may be exposed as shown in FIG. 9E.

Next, as shown in Figure 9f, the flexible substrate 100 was removed using a photoresist remover such as acetone, N-methyl-2-pyrrolidone (NMP), and dimethyl sulfoxide (DMSO). By removing the photoresist 105 layer coated on the flexible substrate 100, an insulating partition wall 104' can be manufactured in the area excluding the area where the ultra-small LED element is actually mounted (P in FIG. 9) on the flexible substrate 100. .

Next, steps 1-3) may include injecting a solution containing a plurality of ultra-small LED elements into the electrode line area surrounded by the insulating partition wall.

Specifically, Figure 10 is a perspective view of the manufacturing process of an ultra-small LED electrode assembly according to a preferred embodiment of the present invention, showing electrode lines 110 and 130 surrounded by an insulating barrier 150 formed on a flexible substrate 100 as shown in Figure 10a. Solutions 120 and 140 containing a plurality of ultra-small LED elements can be injected into the area. In this case, compared to the case of FIG. 1A, a solution containing ultra-small LED elements can be placed directly in the target electrode line area. In addition, after adding the solution, the ultra-small LED elements spread to the outside of the electrode line in the solution to prevent the ultra-small LED elements from being located in unintended electrode line areas and/or areas without electrode lines in order to mount the ultra-small LED elements. There are benefits to doing this. Meanwhile, the description of FIGS. 10B and 10C is the same as the description of FIGS. 1B and 1C in the description of step (2) according to the present invention, so the detailed description will be replaced by the content described later.

Next, the first embodiment of the present invention is step (2), in which power is applied to the electrode line to simultaneously connect a plurality of ultra-small LED elements to the first electrode and the second electrode, as shown in FIG. 1b, to produce a plurality of ultra-small LED elements. It includes the step of self-aligning the elements.

A plurality of ultra-small LED elements included in the ultra-small 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. 1C.

If it is a general LED device, it can be directly physically placed and simultaneously connected to different electrodes spaced apart on the same plane. For example, it would be possible to manually lay down common LED elements and arrange them between different electrodes on a planar electrode.

However, since it is difficult to directly physically arrange ultra-small LED devices like the present invention, there is a problem in that they cannot be simultaneously connected to different ultra-small electrodes spaced apart on the same plane. In addition, if the ultra-small LED element is cylindrical, there may be a problem that it does not self-align when simply inserted into the electrode, but rolls and moves on the electrode due to the cylindrical shape. Accordingly, the present invention can solve the above problem by applying power to the electrode line so that the ultra-small LED elements are simultaneously connected to two different electrodes.

Preferably, the power source may be a fluctuating power source with an amplitude and period, and the waveform may be a sinusoidal wave such as a sine wave or a pulse wave composed of non-sinusoidal waveforms. As an example Apply AC power, or Alternatively, DC power is repeatedly applied at 0V, 30V, 0V, 30V, 0V, 30V to the first electrode 1000 times per second, and 30V, 0V, 30V, 0V, 30V, 0V are repeatedly applied to the second electrode in the opposite direction to the first electrode. By applying this, a fluctuating power source with amplitude and period can be created.

Preferably, the voltage (amplitude) of the power source may be 0.1 V to 1000 V, and the frequency may be 10 Hz to 100 GHz. Self-aligned ultra-small LED elements are contained in a solvent and injected into the electrode line. The solvent can fall on the electrode and evaporate at the same time, and the ultra-small LED elements are asymmetrical due to the induction of an electric field formed by the potential difference between the two electrodes. Because electric charges are induced positively, both ends of an ultra-small LED device can be self-aligned between two different electrodes 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 step (2) may depend on several variables that can be adjusted in step (2). The above variables are the voltage of the applied power (V), the frequency of the power source (F, Hz), the concentration of the solution containing the ultra-small LED elements (C, % by weight of the ultra-small LED), the gap distance between the two electrodes (Z), and the ultra-small LED elements. It can be the aspect ratio (AR, where AR = H/D and D is the diameter of the ultra-small LED) of the LED. Accordingly, the number (N) of ultra-small LED elements simultaneously connected to the first electrode and the second electrode is determined by voltage (V), frequency (F), concentration (C) of the solution containing the ultra-small LED elements, and aspect ratio of the ultra-small LED ( AR) and inversely proportional to the gap distance (Z) between the two electrodes.

This means that ultra-small LED elements are self-aligned between two different electrodes by inducing an electric field formed by the potential difference between the two electrodes. As the intensity of the electric field increases, the number of ultra-small LED elements connected to the electrodes can increase, and the electric field The intensity may be proportional to the potential difference (V) between the two electrodes and inversely proportional to the gap distance (Z) between the two electrodes.

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

Next, in the case of the frequency (F, Hz) of the power source, the charge difference formed in the ultra-small LED elements varies depending on the frequency, so as the frequency increases, the number of ultra-small LED elements connected to the two electrodes can increase. However, if it exceeds a certain value, charge induction may disappear, so the number of ultra-small LED elements connected to the electrode may decrease.

Lastly, as the aspect ratio of the ultra-small LED elements increases, the induced charge due to the electric field increases, so a greater number of ultra-small LED elements can be aligned.

In addition, considering the electrode line with a limited area in terms of space where the ultra-small LED elements can be aligned, if the aspect ratio increases due to the diameter of the ultra-small LED element being fixed while the length of the ultra-small LED element is fixed, it may be connected to the limited electrode line. The number of ultra-small LED devices that can be used can increase.

There is an advantage in that the number of LED elements connected to the electrodes can be adjusted according to the purpose by controlling the various factors mentioned above.

Meanwhile, depending on the aspect ratio of the ultra-small LED device, there may be cases where self-alignment of the ultra-small LED device is difficult even when power is applied to the electrode line in step (2) according to the present invention. Accordingly, according to a preferred embodiment of the present invention, the aspect ratio of the ultra-small LED device included in the present invention may be 1.2 to 100, more preferably 1.2 to 50, and even more preferably 1.5 to 20, Particularly preferably, it may be 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 supply required for self-alignment may be low. However, when manufacturing ultra-small LED devices by dry etching, etc., it may be difficult to manufacture devices with an aspect ratio exceeding 100 due to process limitations.

Preferably, in step (2), the number of ultra-small LED elements ^per 100Х100㎛2 area of the electrode line on which the ultra-small LED elements can be substantially mounted may be 2 to 100,000, and more preferably 10 to 10,000. You can. By including a plurality of ultra-small LED elements per ultra-small LED electrode assembly, it is possible to minimize functional degradation or loss of function of the ultra-small LED electrode assembly due to defects in some of the plurality of elements. Additionally, if the number of ultra-small LED elements exceeds 100,000, the manufacturing cost increases, and there may be problems in aligning the ultra-small LED elements.

Meanwhile, the method of manufacturing an ultra-small LED electrode assembly according to a preferred embodiment of the present invention is a step (3) after the above-described step (2), wherein a metal ohmic layer is formed at the connection portion of the first electrode and the second electrode and the ultra-small LED device. forming a; may include.

The reason for forming a metal ohmic layer at the connection area is that when power is applied to two different electrodes connected to a plurality of ultra-small LEDs, the ultra-small LED elements emit light. At this time, a large resistance may occur between the electrodes and the ultra-small LED elements. It may include forming a metal ohmic layer to reduce resistance.

Specifically, the metal ohmic layer can be formed by the following process, but it cannot necessarily be formed only by the following process, and any conventional metal ohmic layer forming method can be used without limitation.

First, photoresist can be coated to a thickness of 2 to 3 ㎛ on the top of the ultra-small LED electrode assembly that has gone through step (2). The coating may preferably be done by any one of spin coating, spray coating, and screen printing, but is not limited thereto. Afterwards, ultraviolet rays are irradiated in the direction of the photoresist layer coated under the flexible substrate of the ultra-small LED electrode assembly to cure the remaining photoresist layer except for the photoresist layer on the top of the electrode. Afterwards, it is not cured using a typical photoresist solvent. The photoresist layer on top of the unused electrode can be removed.

Preferably, gold or silver may be coated on the top of the electrode from which the photoresist has been removed by vacuum deposition or electrochemical deposition, or gold nanocrystals or silver nanocrystals may be coated by electrospray, but the deposited materials and deposition methods are as described above. It is not limited to. The thickness of the coated metal layer may preferably be 5 to 100 nm, but is not limited thereto.

Afterwards, use a photoresist remover (PR stripper) of acetone, N-methyl-2-pyrrolidone (NMP), or dimethyl sulfoxide (DMSO) to remove the metal layer in the area other than the electrode. It can be removed along with the photoresist, and after the removal, a metal ohmic layer can be formed between the electrode and both ends of the ultra-small LED device that are not coated with an insulating film through heat treatment at 500 to 600°C.

Meanwhile, the second embodiment according to the present invention includes a plurality of electrode lines including (1) a flexible substrate, a first electrode formed on the flexible substrate, and a second electrode formed spaced apart from the first electrode on the same plane. Inserting ultra-small LED elements; and (2) injecting a solvent into the electrode line to simultaneously connect the plurality of ultra-small LED elements to the first electrode and the second electrode, and applying power to the electrode line to self-align the plurality of ultra-small LED elements; Manufactures ultra-small LED electrode assemblies, including.

At this time, the ultra-small LED device of the second embodiment is the same as that described in the first embodiment. And, the width length of the first electrode (X), the width length of the two electrodes (Y), the distance between the first electrode and the second electrode adjacent to the first electrode (Z), and the length of the ultra-small LED element (H) satisfies relational expression 1 above.

The detailed description of the second embodiment according to the present invention will focus on the differences from the first embodiment according to the present invention described above.

In the second embodiment, unlike the first embodiment according to the present invention described above, in step (1), an ultra-small LED element is introduced into the electrode line rather than a solution containing the ultra-small LED element.

In the case of the ultra-small LED electrode assembly manufactured according to the above-described first embodiment, as the ultra-small LED elements are put into the electrode line in a solution state, the ultra-small LED elements are clustered and placed only in a specific part of the electrode line area, or the ultra-small LED elements are in the solution. As it floats and spreads out to the outside of the electrode line, ultra-small LED elements can be concentrated and mounted only on the outside of the electrode line.

The second embodiment compensates for this by concentrating and mounting ultra-small LED elements in the target area of the electrode line while distributing them evenly in the target area. It is also possible to minimize the fact that the ultra-small LED elements are clustered and mounted. .

For this purpose, in the second embodiment, instead of putting the ultra-small LED elements into the electrode line in a solution state, after adding the ultra-small LED elements, a solvent is added as a mobile phase for moving the ultra-small LED elements in step (2) described later. , power can be applied to mount ultra-small LED elements by focusing them on the target electrode area.

Specifically, Figure 11 is a perspective view showing the steps of manufacturing an ultra-small LED electrode assembly according to a second preferred embodiment of the present invention. Figure 11a shows a first electrode 110 formed on a flexible substrate 100, and the first electrode. It shows a second electrode 130 formed on the same plane and spaced apart from the other, and an ultra-small LED element 120 inserted into an electrode line including the first electrode 110 and the second electrode 130.

In step (1) of the second embodiment, the detailed description of the electrode line and the ultra-small LED element is omitted as it is the same as the description in the first embodiment according to the present invention described above.

The method of injecting the ultra-small LED element into the electrode line in step (1) of the second embodiment according to the present invention is not particularly limited in the present invention, and as a non-limiting example, the ultra-small LED element is inserted into the core portion and the core portion. Ultra-small LED devices can also be introduced into the electrode line by manufacturing them from core-shell structured particles or core-sheath composite fibers including a surrounding polymer shell. At this time, the specific type of polymer component forming the shell portion (or sheath portion) may be used without limitation as long as it does not affect the ultra-small LED element to be supported on the core portion (or core portion), but is preferably the type described later ( It may be desirable to use a polymer that can be dissolved by the solvent to be added in step 2). Additionally, the diameter, shape, etc. of the particles or composite fibers may be changed depending on the purpose, and are not particularly limited in the present invention.

In addition, in step (1) of the second embodiment according to the present invention, the ultra-small LED element can be inserted into the area of the electrode line surrounded by the insulating barrier, and due to the insulating barrier, when the solvent is added in step (2), which will be described later, the ultra-small LED element can be inserted into the area of the electrode line surrounded by the insulating barrier. There is an advantage in minimizing placement of LED elements outside of the intended electrode line. The description of the insulating partition wall is omitted since it is the same as the description in the first embodiment according to the present invention described above.

Next, in the second embodiment, in step (2), a solvent is added to the electrode line to simultaneously connect a plurality of ultra-small LED elements to the first electrode and the second electrode, and power is applied to the electrode line to connect a plurality of ultra-small LED elements. A step of self-aligning ultra-small LED elements is performed.

Specifically, as shown in FIG. 11b, when the solvent 140 is injected onto the electrode lines 110 and 130 and power is applied to the electrode lines 110 and 130 to self-align the ultra-small LED elements, the electrode lines are aligned as shown in FIG. 11c. A ultra-small LED element 120 can be connected to the first electrode 110 and the second electrode 130. The specific type of solvent 140 added in step (2), the intensity of power applied, etc. are the same as the description of the first embodiment according to the present invention and are therefore omitted.

The amount of solvent added in step (2) may be 100 to 12,000 parts by weight based on 100 parts by weight of the ultra-small LED device added in step (1). If more than 12,000 parts by weight of solvent is added, the amount of solvent is too large and the ultra-small LED element spreads to places other than the target electrode line area due to the solvent, and the ultra-small LED element is mounted in the target mounting area in the electrode line. There is a problem that the number may be reduced, and if less than 100 parts by weight is added, there may be a problem that the movement or alignment of individual ultra-small LED elements may be disturbed.

In step (2), the input of the solvent and the application of power can be performed simultaneously or sequentially regardless of the order.

Specifically, Figure 12 is a perspective view and a partial enlarged view of an ultra-small LED electrode assembly according to a preferred embodiment, including first electrodes 410 and 411 formed on a flexible substrate 400, the first electrodes 410 and 411, and It includes second electrodes 430 and 431 spaced apart from each other on the same plane and a plurality of ultra-small LED elements 420 simultaneously connected to the first and second electrodes.

The advantage gained by locating the first electrode 411 and the second electrode 431 on the same plane is that in the case of ultra-small LED devices of nanoscale size, it is very difficult to connect the electrodes in an upright three-dimensional shape. If placed on the same plane, the ultra-small LED elements can be connected lying down, so there is no need to make the ultra-small LED elements stand upright and connect them to the electrodes.

In addition, as the electrodes are formed spaced apart on the same plane, the ultra-small LED elements can be connected to the flexible substrate while lying down, and through this, the light extraction efficiency of the ultra-small LED elements can be significantly improved. Even more preferably, the ultra-small LED elements can lie parallel to the flexible substrate.

Specifically, in FIG. 12, it can be seen that the ultra-small LED 421 is simultaneously connected to the first electrode 412 and the second electrode 432 and is in a shape lying parallel to the flexible substrate.

Meanwhile, the ultra-small LED device of the present invention is connected to the electrode in a "lying" shape parallel to the flexible substrate, and as a result, the ultra-small LED electrode assembly of the present invention can have significantly excellent light extraction efficiency. In general, the performance of LED devices is evaluated by external quantum efficiency.

External quantum efficiency is expressed as the ratio of the number of photons escaping from the LED, that is, into the atmosphere, during a unit time to the number of carriers injected into the LED device during a unit time. The following relational equation is established between the external quantum efficiency, internal quantum efficiency and light extraction efficiency.

[Relational Expression]

External photon efficiency = Internal photon efficiency × Light extraction efficiency

Internal photon efficiency refers to the ratio of the number of photons emitted from the active layer during unit time to the number of carriers injected into the LED device per unit time, and light extraction efficiency refers to the ratio of the number of photons emitted from the active layer per unit time. It refers to the ratio of the number of photons escaping into the atmosphere per unit time. Ultimately, in order to improve the performance of LED devices, it is important to improve their efficiency.

However, in terms of light extraction efficiency, the extraction efficiency of light emitted into the air through the upper and lower electrodes or the n-conductive semiconductor layer and the p-conductive semiconductor layer of the current thin-film ultra-small LED device is very low. This is because most of the light generated from a thin-film type LED device is totally reflected due to the difference in refractive index at the interface between the high-refractive index semiconductor layer and the low-refractive air layer, so it is trapped in the semiconductor layer. As a result, a significant amount of light generated from the active layer does not escape in the direction in which the light is extracted. This is because it is reabsorbed inside the LED device or disappears as heat. This is due to the fact that the LED device is manufactured using an existing thin film structure.

To solve this problem, the flat interface between the high refractive index semiconductor layer and the air layer is eliminated by laying down the ultra-small LED element and connecting it to the electrode. This minimizes the probability of total internal reflection, so the light generated from the ultra-small LED element is not extracted to the outside and is not extracted to the inside. By minimizing the trapped light, most of the light is emitted to the outside. As a result, it is possible to provide an ultra-small LED electrode assembly that solves the problem of conventional light extraction degradation.

The ultra-small LED electrode assembly may include a single or plural unit electrode, that is, an array area in which two electrodes that can be independently driven by arranging ultra-small LED elements at once are arranged, and the unit electrode has an area of 1㎛ ² to 100 cm ^2. And, more preferably, it may be 10㎛ ² to 100 mm ² , but is not limited thereto.

If the unit electrode area included in the ultra-small LED electrode assembly is less than 1 ㎛ ² , manufacturing the unit electrode may be difficult, and since the length of the ultra-small LED must be further reduced, there may also be problems in manufacturing the ultra-small LED. If it exceeds 100 cm ² , the number of ultra-small LED elements included increases, which may increase the manufacturing cost, and there may be a problem of non-uniform distribution of the aligned ultra-small LED elements.

Preferably, the number of ultra-small LED elements ^per area of 100 By including a plurality of ultra-small LED elements per ultra-small LED electrode assembly, it is possible to minimize functional degradation or loss of function of the ultra-small LED electrode assembly due to defects in some of the plurality of elements. In addition, if the number of ultra-small LED elements exceeds 100,000, the manufacturing cost increases, and there may be problems in aligning the ultra-small LED elements. The “area of the ultra-small LED electrode assembly” refers to the area of the electrode area where the ultra-small LED can be substantially mounted.

Although the present invention has been described above with a focus on embodiments, this is only an example and does not limit the embodiments of the present invention, and those skilled in the art will be able to understand the essential characteristics of the present invention. It can be seen that various modifications and applications not exemplified above are possible without departing from the scope. For example, each component specifically shown in the embodiments of the present invention can be modified and implemented. And these variations and differences in application should be construed as being included in the scope of the present invention as defined in the appended claims.

The present invention will be described in more detail through the following examples, but the following examples do not limit the scope of the present invention, and should be interpreted to aid understanding of the present invention.

[Example]

<Example 1>

An electrode line as shown in Figure 3 was manufactured on a flexible substrate made of quartz with a thickness of 800 ㎛. At this time, the width of the first electrode in the electrode line was 3 ㎛, the width of the second electrode was 3 ㎛, the gap between the first electrode and the adjacent second electrode was 2 ㎛, and the thickness of the electrode was 0.2 ㎛. The first electrode and The material of the second electrode was titanium/gold, and the area of the electrode line where the ultra-small LED element was mounted was 4.2×10 ⁷ ㎛ ² .

Afterwards, an insulating barrier as shown in FIG. 9 was formed on the flexible substrate, the material of the insulating barrier was silicon dioxide, the height from the flexible substrate to the end of the insulating barrier was 0.1 ㎛, and an ultra-small LED element was mounted on the electrode line. An insulating barrier was formed on the flexible substrate except for the area (area 4.2×10 ⁷ ㎛ ² ).

Afterwards, an ultra-small LED device with specifications as shown in Table 1 below, a structure as shown in Figure 6a, and an insulating film coated with a thickness of 0.02㎛ on the outer surface of the active layer portion of the ultra-small LED device was mixed with 1.0 parts by weight of acetone for 100 parts by weight. A solution containing an ultra-small LED device was prepared.

The prepared solution is dropped onto the electrode line area surrounded by an insulating barrier on the flexible substrate, and then a voltage V _AC = 30 V and a frequency of 950 are applied to the electrode line. kHz An ultra-small LED electrode assembly was manufactured by applying AC power for 1 minute.

texture Length (㎛) diameter first electrode layer chrome 0.03 0.6㎛ First conductive semiconductor layer n-GaN 1.64 0.6㎛ active layer InGaN 0.1 0.6㎛ Second conductive semiconductor layer p-GaN 0.2 0.6 second electrode layer chrome 0.03 0.6 insulating film aluminum oxide - 0.02 (thickness) Ultra-small LED element - 2 0.62

<Example 2>

It was manufactured in the same manner as in Example 1, but had the specifications as shown in Table 2 below and the structure as shown in Figure 6b. An electronic pushing film was formed surrounding the outer surface of the first conductive semiconductor layer portion of the ultra-small LED device, and a second A solution containing an ultra-small LED device was prepared by mixing 1.0 parts by weight of acetone with 100 parts by weight of an ultra-small LED device formed by a hole-pushing film surrounded on the outer surface of the conductive semiconductor layer and the active layer.

The prepared solution is dropped onto the electrode line area surrounded by an insulating barrier on the flexible substrate, and then a voltage V _AC = 30 V and a frequency of 950 are applied to the electrode line. kHz An ultra-small LED electrode assembly was manufactured by applying AC power for 1 minute.

division texture Length (㎛) diameter first electrode layer chrome 0.03 0.6 First conductive semiconductor layer n-GaN 1.64 0.6 active layer InGaN 0.1 0.6 Second conductive semiconductor layer p-GaN 0.2 0.6 second electrode layer chrome 0.03 0.6 Electronic pushing film SiO ₂ 1.62 ~ 1.64 0.02 (thickness) Hole pushing film _ZrO2 0.28 ~ 0.29 0.02 (thickness) Ultra-small LED element - 2 0.62

<Example 3>

It is manufactured in the same manner as in Example 1, but has the specifications as shown in Table 3 below and the structure as shown in Figure 6d. An electronic pushing film is formed surrounding the outer surface of the first conductive semiconductor layer of the ultra-small LED device, and the active layer is A solution containing an ultra-small LED device was prepared by mixing 1.0 parts by weight of acetone with 100 parts by weight of an ultra-small LED device formed by being surrounded by an insulating film and a hole-pushing film formed on the outer surface of the second conductive semiconductor layer and the active layer.

The prepared solution is dropped onto the electrode line area surrounded by an insulating barrier on the flexible substrate, and then a voltage V _AC = 30 V and a frequency of 950 are applied to the electrode line. kHz An ultra-small LED electrode assembly was manufactured by applying AC power for 1 minute.

division texture Length (㎛) diameter first electrode layer chrome 0.03 0.6 First conductive semiconductor layer n-GaN 1.64 0.6 active layer InGaN 0.1 0.6 Second conductive semiconductor layer p-GaN 0.2 0.6 second electrode layer chrome 0.03 0.6 insulating film aluminum oxide - 0.02 (thickness) Electronic pushing film SiO ₂ 1.62 ~ 1.64 0.036 (thickness) Hole pushing film _ZrO2 0.28 ~ 0.29 0.036 (thickness) Ultra-small LED element - 2 0.62

<Comparative Example 1>

An ultra-small LED electrode assembly was manufactured in the same manner as in Example 1, but using an ultra-small LED device without a protective film on the first conductive semiconductor layer and the second conductive semiconductor layer and an insulating film on the active layer in the ultra-small LED device of Example 1. Manufactured.

<Experimental Example 1>

For the ultra-small electrode assembly manufactured in Examples 1 to 3 and Comparative Example 1, the voltage V _AC = 30 V, frequency 950 on the electrode line kHz The luminous efficiency of an ultra-small LED device that emits blue light was measured by applying phosphorus AC power for 1 minute, and the results are shown in Table 4 below.

The luminous efficiency in Table 4 below shows the relative luminous efficiency based on the ultra-small LED electrode assembly of Example 1.

division Luminous efficiency (%) Example 1 100.0% Example 2 106.9% Example 3 104.2% Comparative Example 1 64.3%

Looking at the luminous efficiency measurement results in Table 4, Examples 1 to 3 showed very excellent luminous efficiency compared to Comparative Example 1. In Comparative Example 1, the active layer of the LED device was in contact with the electrode in the LED electrode assembly, causing electrical damage. Because many short circuits occurred, low luminous efficiency was shown compared to Examples 1 to 3.

And, compared to Example 1, Example 3, in which protective films were further formed on the first and second conductive semiconductor layers, showed approximately 4.2% higher luminous efficiency than Example 1.

In addition, in the case of Example 3, in which an insulating film was not formed in the active layer, but a hole pushing film was formed instead, there was an effect of preventing electrical short circuit, and it was confirmed that it had superior luminous efficiency than Examples 1 and 3.

Although a preferred embodiment of the present invention has been described above, it is clear that the present invention can use various changes, modifications, and equivalents, and can be equally applied by appropriately modifying the above embodiment. Accordingly, the above description does not limit the scope of the present invention as defined by the limitations of the following claims.

11: first electrode layer 12: second electrode layer 21: first conductive semiconductor layer
22: Active layer 23: Second conductive semiconductor layer 30: Insulating film
31: Hole pushing film 32: Electronic pushing film 35: Protective film
40: Hydrophobic film

Claims (15)

An LED electrode assembly including a plurality of ultra-small LED elements that emit UV light with a wavelength of 200 to 400 nm,
The ultra-small LED device is,
first electrode layer; a first conductive semiconductor layer formed on the first electrode layer; an active layer formed on the first conductive semiconductor layer; a second conductive semiconductor layer formed on the active layer; And a second electrode layer formed on the second conductive semiconductor layer,
The ultra-small LED device includes a protective film; or an insulating film and a protective film; included on the outer surface,
The protective film surrounds the exposed outer surface of the second conductive semiconductor layer, or the exposed outer surface of the second conductive semiconductor layer and at least a portion of the active layer, and moves holes on the exposed outer surface surface toward the center. Hole pushing film to do this; and an electron pushing film surrounding the exposed outer surface of the first conductive semiconductor layer to move electrons on the exposed outer surface surface toward the center,
When the ultra-small LED device includes only a protective film on the outer surface, the electronic pushing film surrounds the outer surface of the first conductive semiconductor layer, and the hole pushing film surrounds the outer surface of the second conductive semiconductor layer, or the active layer and the second conductive semiconductor layer. It is provided as an outermost film surrounding the outer surface of the conductive semiconductor layer. In this case, the electronic pushing film includes SiNx or SiO ₂ , and the hole pushing film includes ZrO ₂ , MoO, Sc ₂ O ₃ , La ₂ O ₃ , Contains one or more selected from MgO, Y ₂ O ₃ , Ga ₂ O ₃ , TiO ₂ , ZnS, Ta ₂ O ₅ and n-MoS ₂ ,
When the outer surface of the ultra-small LED device includes both an insulating film and a protective film, the outer surface of the first conductive semiconductor layer includes an electronic pushing film, the outer surface of the active layer includes an insulating film, and the second conductive layer includes an insulating film. The outer surface of the semiconductor layer includes a hole pushing film, wherein the insulating film includes Al ₂ O ₃ , the electronic pushing film includes SiNx or SiO ₂ , and the hole pushing film includes ZrO ₂ and MoO. , Sc ₂ O ₃ , La ₂ O ₃ , MgO, Y ₂ O ₃ , Ga ₂ O ₃ , TiO ₂ , ZnS, Ta ₂ O ₅ and n-MoS ₂ ,
An ultra-small-LED flexible skin patch, wherein each of the hole-type film and the electronic film has a thickness of 1 to 50 nm.
The method of claim 1, wherein the LED electrode assembly,
flexible substrate;
an electrode line including a first electrode formed on the flexible substrate and a second electrode formed on the same plane and spaced apart from the first electrode; and
It includes the plurality of ultra-small LED elements simultaneously connected to the first electrode and the second electrode,
The width length of the first electrode (X), the width length of the second electrode (Y), the gap distance between the first electrode and the second electrode (Z), and the length (H) of the ultra-small LED element satisfy the following relational equation 1. An ultra-small LED flexible skin patch comprising:
[Relationship 1]
0.5Z ≤ H <
delete delete delete delete delete According to paragraph 1,
An ultra-small LED flexible skin patch, characterized in that the length of the ultra-small LED device is 100 nm to 10 ㎛ and the aspect ratio is 1.2 to 100.
The ultra-small LED flexible skin patch according to claim 1, further comprising a hydrophobic coating on the outer surface of at least one of the insulating coating and the protective coating to prevent agglomeration between the ultra-small LED elements.
The method of claim 1, wherein the ultra-small LED device is
LED device that emits UVC light with a wavelength of 200 to 280 nm; LED device that emits UVB light with a wavelength of 280 to 320 nm; and an LED device that emits UVA light with a wavelength of 320 to 400 nm; An ultra-small-LED flexible skin patch comprising one or more types selected from among.
According to paragraph 1,
A transparent flexible substrate including a skin adhesive layer including an adhesive pad or adhesive film; and
An ultra-small-LED flexible skin patch comprising: the LED electrode assembly provided on the substrate.
The method of claim 2, wherein the LED electrode assembly is encapsulated with an encapsulating material,
An ultra-small-LED flexible skin patch, characterized in that each of the first electrode and the second electrode is a flexible electrode.
delete delete It is manufactured by combining a transparent flexible substrate containing a skin adhesive layer and an ultra-small LED electrode assembly.
The ultra-small-LED electrode assembly is
(1) Injecting a solution containing a plurality of ultra-small LED elements into an electrode line including a flexible substrate, a first electrode formed on the flexible substrate, and a second electrode formed spaced apart from the first electrode on the same plane. ; and
(2) self-aligning the plurality of ultra-small LED elements by applying power to the electrode line in order to simultaneously connect the plurality of ultra-small LED elements to the first electrode and the second electrode; manufacturing an ultra-small LED electrode assembly including; However,
The ultra-small LED device includes a first electrode layer; a first conductive semiconductor layer formed on the first electrode layer; an active layer formed on the first conductive semiconductor layer; a second conductive semiconductor layer formed on the active layer; And a second electrode layer formed on the second conductive semiconductor layer,
The ultra-small LED device is,
The ultra-small LED device includes a protective film; or an insulating film and a protective film; included on the outer surface,
The protective film surrounds the exposed outer surface of the second conductive semiconductor layer, or the exposed outer surface of the second conductive semiconductor layer and at least a portion of the active layer, and moves holes on the exposed outer surface surface toward the center. Hole pushing film to do this; and an electron pushing film surrounding the exposed outer surface of the first conductive semiconductor layer to move electrons on the exposed outer surface surface toward the center,
When the ultra-small LED device includes only a protective film on the outer surface, the electronic pushing film surrounds the outer surface of the first conductive semiconductor layer, and the hole pushing film surrounds the outer surface of the second conductive semiconductor layer, or the active layer and the second conductive semiconductor layer. It is provided as an outermost film surrounding the outer surface of the conductive semiconductor layer. In this case, the electronic pushing film includes SiNx or SiO ₂ , and the hole pushing film includes ZrO ₂ , MoO, Sc ₂ O ₃ , La ₂ O ₃ , Contains one or more selected from MgO, Y ₂ O ₃ , Ga ₂ O ₃ , TiO ₂ , ZnS, Ta ₂ O ₅ and n-MoS ₂ ,
When the outer surface of the ultra-small LED device includes both an insulating film and a protective film, the outer surface of the first conductive semiconductor layer includes an electronic pushing film, the outer surface of the active layer includes an insulating film, and the second conductive layer includes an insulating film. The outer surface of the semiconductor layer includes a hole pushing film, where the insulating film is Si ₃ N _4, Al ₂ O _3, HfO ₂ or It includes TiO ₂ , the electronic pushing film includes SiNx or SiO ₂ , and the hole pushing film includes ZrO ₂ , MoO, Sc ₂ O ₃ , La ₂ O ₃ , MgO, Y ₂ O ₃ , Ga ₂ O ₃ , TiO ₂ , ZnS, Ta ₂ O ₅ and n-MoS ₂ , including one or more selected from among,
A method of manufacturing an ultra-small LED flexible skin patch, characterized in that each of the hole-type film and the electronic film has a thickness of 1 to 50 nm.