阅读说明：本技术 像素结构 (Pixel structure ) 是由 赵显敏 金大贤 任铉德 姜钟赫 朴哉柄 李周悦 曹治乌 洪性珍 于 2017-06-14 设计创作，主要内容包括：公开了像素结构。所述像素结构包括：基体基底；第一电极,位于所述基体基底上；第二电极,设置为围绕所述第一电极的至少一部分；以及多个LED元件,分别连接到所述第一电极和所述第二电极,并且沿不同的方向径向地布置。(A pixel structure is disclosed. The pixel structure includes: a base substrate; a first electrode on the base substrate; a second electrode disposed to surround at least a portion of the first electrode; and a plurality of LED elements respectively connected to the first and second electrodes and radially arranged in different directions.)

1. A pixel structure, the pixel structure comprising:

a base substrate;

a first electrode on the base substrate;

a second electrode disposed to surround at least a portion of the first electrode; and

a plurality of LED elements respectively connected to the first and second electrodes and radially arranged in different directions.

2. The pixel structure of claim 1, wherein a first end of each of the plurality of LED elements is directly connected to the first electrode and a second end of each LED element is directly connected to the second electrode.

3. The pixel structure according to claim 1, wherein two LED elements adjacent to each other from among the plurality of LED elements are arranged in a first direction and a second direction intersecting the first direction, respectively, wherein the first direction and the second direction form an acute angle.

4. The pixel structure according to claim 1, wherein imaginary lines extending from different directions along which the plurality of LED elements are arranged, respectively, intersect at a virtual contact point, wherein the virtual contact point is located in the first electrode.

5. The pixel structure of claim 1, wherein at least a portion of the second electrode is discontinuously disposed.

6. The pixel structure of claim 1, wherein the second electrode comprises a first portion of the second electrode and a second portion of the second electrode.

7. The pixel structure of claim 6, wherein the first portion of the second electrode is electrically connected to the second portion of the second electrode.

8. The pixel structure of claim 6, wherein the first portion of the second electrode and the second portion of the second electrode are spaced apart from each other.

9. The pixel structure of claim 1, further comprising:

a transistor electrically connected to the first electrode; and

a power supply wiring electrically connected to the second electrode.

10. The pixel structure of claim 9, further comprising:

an insulating layer disposed over the transistor and

wherein the first electrode and the second electrode are disposed on the insulating layer.

11. The pixel structure of claim 1, wherein the first electrode and the second electrode are plural, the pixel structure further comprising:

and the electrode wire is connected with the plurality of second electrodes.

12. The pixel structure of claim 1, wherein a separation distance between the first electrode and the second electrode is 1 μ ι η or more and 7 μ ι η or less.

13. The pixel structure of claim 1, wherein a voltage difference applied to the first and second electrodes is 10V to 50V.

14. The pixel structure of claim 1, wherein a distance between the first electrode and the second electrode is inversely proportional to a potential difference between the first electrode and the second electrode.

15. The pixel structure of claim 1, wherein a first separation distance between the first and second electrodes along a first direction is different from a second separation distance between the first and second electrodes along a second direction.

Technical Field

One or more embodiments relate to a pixel structure, a display device including the pixel structure, and a method of manufacturing the pixel structure.

Background

Light Emitting Diode (LED) elements have high photoelectric conversion efficiency, low power consumption and semi-permanent service life, and are also environmentally friendly. Therefore, the LED element has been used for signal lamps, mobile phones, automobile lamps, outdoor electronic scoreboards, Liquid Crystal Display (LCD) backlight units (BLU), indoor/outdoor lighting devices, and the like.

In order to use the LED element in a lighting device or a display, the LED element needs to be connected to an electrode capable of supplying power to the LED element. Accordingly, various studies have been made on the arrangement of the LED elements and the electrodes with respect to the purpose of use, reduction of electrode space, and a method of manufacturing the electrodes.

The method of arranging the LED element and the electrode may be classified into a method of directly growing the LED element on the electrode and a method of arranging the LED element on the electrode after separately growing the LED element. In the latter case, a conventional three-dimensional (3D) LED element may be connected to the electrode after being erected in a vertical position. However, when the LED element has an extremely small nano size, it is difficult to make the LED element stand upright in a vertical position on the electrode.

Disclosure of Invention

One or more embodiments include a pixel structure, a display device including the pixel structure, and a method of manufacturing the pixel structure, whereby abnormal alignment deviation of Light Emitting Diode (LED) elements can be prevented by aligning and connecting a plurality of independently manufactured extremely small nano-sized LED elements between two electrodes.

Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the embodiments.

According to one or more embodiments, a pixel structure includes: a base substrate; a first electrode disposed in an upper portion of the base substrate; a second electrode having a circular shape extending in a circumferential direction around the first electrode; and a plurality of very small-sized LED elements connected to the first and second electrodes.

The pixel structure may further include a driving transistor electrically connected to the first electrode and a power supply wiring electrically connected to the second electrode.

The first electrode may include a plurality of first electrodes, the second electrode may include a plurality of second electrodes, and the pixel structure may further include an electrode line configured to connect the plurality of second electrodes to each other.

The separation distance between the first electrode and the second electrode may be about 1 μm or more and about 7 μm or less.

The second electrode may include a second-1 electrode and a second-2 electrode having a semicircular shape, and the second-1 electrode and the second-2 electrode may be spaced apart from each other.

The pixel structure may further include a driving transistor electrically connected to the first electrode, and the power supply wiring is electrically connected to the second-1 electrode and the second-2 electrode, respectively.

The first electrode may include a plurality of first electrodes, the second electrode may include a plurality of second electrodes, and the pixel structure may further include a first electrode line configured to connect the plurality of second-1 electrodes to each other, and a second electrode line configured to connect the plurality of second-2 electrodes to each other.

A first-1 separation distance between the second-1 electrode and the first electrode may be different from a first-2 separation distance between the second-2 electrode and the first electrode.

The first-1 separation distance and the first-2 separation distance may each be about 1 μm or more and about 7 μm or less.

According to one or more embodiments, a display device includes any one of the above-described pixel structures and a driving circuit connected to the pixel structure.

According to one or more embodiments, a method of fabricating a pixel structure includes: applying a plurality of extremely small-sized LED elements and a solvent onto a first electrode and a second electrode having a circular shape extending in a circumferential direction around the first electrode; applying different voltages to the first electrode and the second electrode, respectively; the very small size LED element is aligned between the first electrode and the second electrode.

The separation distance between the first electrode and the second electrode may be about 1 μm or more and about 7 μm or less, and the voltage difference between the first electrode and the second electrode may be about 10V or more and about 50V or less.

When the power voltages applied to each of the first and second electrodes are different from each other, a first electric field may be generated radially around the first electrode between the first and second electrodes.

The first electrode may include a plurality of first electrodes, the second electrode may include a plurality of second electrodes, and the same voltage may be applied to each of the first and second electrodes.

The second electrode may include a second-1 electrode and a second-2 electrode having a semicircular shape, and the second-1 electrode and the second-2 electrode may be spaced apart from each other.

The first electrode may include a plurality of first electrodes, the second-1 electrode may include a plurality of second-1 electrodes and the second-2 electrode may include a plurality of second-2 electrodes, and when a voltage is applied to the first electrode and the second electrode, the same voltage may be applied to the first electrode, the second-1 electrode, and the second-2 electrode, and different voltages may be applied to the second-1 electrode and the second-2 electrode, respectively.

A first-1 electric field may be generated between the first electrode and the second-1 electrode, a first-2 electric field may be generated between the first electrode and the second-2 electrode, and a first electric field may be generated radially around the first electrode as a combination of the first-1 electric field and the first-2 electric field.

A second electric field towards one of the second-1 electrode and the second-2 electrode may be arranged between the second-1 electrode and the second-2 electrode.

A first-1 separation distance between the second-1 electrode and the first electrode may be different from a first-2 separation distance between the second-2 electrode and the first electrode.

The first-1 separation distance and the first-2 separation distance may each be about 1 μm or more and about 7 μm or less, and the voltage difference between the first electrode and the second-1 electrode and the voltage difference between the first electrode and the second-2 electrode may be about 10V or more and about 50V or less.

Drawings

These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a perspective view of a pixel structure according to an embodiment;

fig. 2A and 2B are cross-sectional views taken along line a-a' of the pixel structure of fig. 1;

fig. 3 is a perspective view of an extremely small-sized LED element according to an embodiment;

fig. 4A is a perspective view of a pixel structure according to an embodiment;

fig. 4B is a perspective view of a pixel structure according to an embodiment;

fig. 4C is a perspective view of a pixel structure according to an embodiment;

fig. 4D is a perspective view of a pixel structure according to an embodiment;

FIG. 5A is a perspective view of a pixel structure according to another embodiment;

FIG. 5B is a cross-sectional view taken along line B-B' of the pixel structure of FIG. 5A;

FIG. 6A is a perspective view of a pixel structure according to another embodiment;

FIG. 6B is a perspective view of a pixel structure according to another embodiment;

FIG. 6C is a perspective view of a pixel structure according to another embodiment;

FIG. 6D is a perspective view of a pixel structure according to another embodiment;

fig. 7 is a conceptual diagram of a display device according to an embodiment.

Detailed Description

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as limited to the description set forth herein. Therefore, only the embodiments are described below to explain aspects of the present specification by referring to the figures. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. When an expression such as "at least one of … …" appears after a list of elements, the entire list of elements is modified rather than modifying individual elements in the list.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. The same reference numerals are used to designate the same elements, and a repetitive description thereof will be omitted.

It will be understood that, although the terms first, second, etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are only used to distinguish one component from another.

The use of the expression in the singular includes the expression in the plural unless it has a distinctly different meaning in the context.

It will be further understood that the terms "comprises" and/or "comprising," when used herein, specify the presence of stated features or components, but do not preclude the presence or addition of one or more other features or components.

The size of elements in the drawings may be exaggerated for convenience of illustration. In other words, since the sizes and thicknesses of elements in the drawings are arbitrarily illustrated for convenience of explanation, the following embodiments are not limited thereto.

Fig. 1 is a perspective view of a pixel structure 1 according to an embodiment. Fig. 2A and 2B are cross-sectional views taken along line a-a' of the pixel structure 1 of fig. 1. Fig. 3 is a perspective view of an extremely small-sized LED element 40 according to the embodiment.

Referring to fig. 1 to 3, a pixel structure 1 according to an embodiment may include a base substrate 10, first and second electrodes 21 and 22 disposed in an upper portion of the base substrate 10, an extremely small-sized LED element 40, and a solvent 50. A plurality of pixel structures 1 may be arranged on a display area of a display device 1000 (see fig. 7) which will be described later.

The base substrate 10 on which the first electrode 21 and the second electrode 22 are disposed may be, for example, a glass substrate, a crystalline substrate, a sapphire substrate, a plastic substrate, or a bendable flexible polymer film, but the present disclosure is not limited thereto. The area of the base substrate 10 according to the embodiment may vary according to the areas of the first and second electrodes 21 and 22 disposed in the upper portion of the base substrate 10 and the size and number of the extremely small-sized LED elements 40 disposed between the first and second electrodes 21 and 22, which will be described later.

A buffer layer 601 may also be included in the upper portion of the base substrate 10. The buffer layer 601 may prevent ion impurities from diffusing into the upper surface of the base substrate 10, may also prevent moisture or external air from penetrating into the upper surface of the base substrate 10, and may planarize the surface of the base substrate 10. In some embodiments, the buffer layer 601 may include an inorganic material such as silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, titanium oxide, or titanium nitride, an organic material such as polyimide, polyester, or acryl, or a stack thereof. However, buffer layer 601 is not an essential component and may be omitted. The buffer layer 601 may be formed by various deposition methods such as a Plasma Enhanced Chemical Vapor Deposition (PECVD) method, an atmospheric pressure cvd (apcvd) method, or a low pressure cvd (lpcvd) method.

The first thin film transistor TFT1 may be a driving thin film transistor for driving the extremely small-sized LED element 40 and includes a first active layer 611, a first gate electrode 612, a first drain electrode 613, and a first source electrode 614. The first gate insulating layer 602 may be interposed between the first gate electrode 612 and the first active layer 611 to insulate them from each other. The first gate electrode 612 may be formed on the first gate insulating layer 602 to overlap a portion of the first active layer 611.

The second thin film transistor TFT2 may include a second active layer 621, a second gate electrode 622, a second drain electrode 623, and a second source electrode 624. The first gate insulating layer 602 may be interposed between the second gate electrode 622 and the second active layer 621 to insulate them from each other.

The first and second active layers 611 and 621 may be formed on the buffer layer 601. An inorganic semiconductor such as amorphous silicon or polycrystalline silicon or an organic semiconductor may be used for the first active layer 611 and the second active layer 621. In some embodiments, the first active layer 611 may be formed of an oxide semiconductor. For example, the oxide semiconductor may include an oxide of a material selected from group 12, 13, and 14 metal elements such as zinc (Zn), indium (In), gallium (Ga), tin (Sn), cadmium (Cd), germanium (Ge), hafnium (Hf), and a combination thereof.

The first gate insulating layer 602 may be disposed on the buffer layer 601 and may cover the first and second active layers 611 and 621. The second gate insulating layer 603 may cover the first gate electrode 612 and the second gate electrode 622.

Each of the first and second gate electrodes 612 and 622 may include a single film, a multi-layer film, or an alloy such as Al: Nd or Mo: W, such as gold (Au), silver (Ag), copper (Cu), nickel (Ni), platinum (Pt), palladium (Pd), aluminum (Al), molybdenum (Mo), or chromium (Cr).

The first gate insulating film 602 and the second gate insulating film 603 may include an inorganic film such as silicon oxide, silicon nitride, or a metal oxide, and may be formed of a single layer or a plurality of layers.

An interlayer insulating film 604 may be formed on the second gate insulating film 603. The interlayer insulating film 604 may be formed of an inorganic film such as silicon oxide or silicon nitride. The interlayer insulating film 604 may include an organic film.

Each of the first drain electrode 613 and the first source electrode 614 may be formed on the interlayer insulating film 604. Each of the first drain electrode 613 and the first source electrode 614 may contact the first active layer 611 through a contact hole. In addition, each of the second drain electrode 623 and the second source electrode 624 may be formed on the interlayer insulating film 604, and each of the second drain electrode 623 and the second source electrode 624 may contact the second active layer 621 through a contact hole. Each of the first drain electrode 613, the second drain electrode 623, the first source electrode 614, and the second source electrode 624 may include a metal, an alloy, a metal nitride, a conductive metal oxide, a transparent conductive material, and the like.

However, the structures of the thin film transistors TFT1 and TFT2 are not limited to the above structures and may have other structures. For example, the thin film transistors TFT1 and TFT2 may have a top gate structure, or a bottom gate structure in which the first gate electrode 612 is disposed under the first active layer 611 is also possible.

The planarization film 605 may cover the thin film transistor TFT1 and the TFT2 and may be provided on the interlayer insulating film 604. The planarization film 605 may planarize the interlayer insulating film 604 to improve the light emission effect of the extremely small-sized LED element 40 to be formed on the planarization film 605. Further, the planarization film 605 may include a through hole exposing a part of the first drain electrode 613.

The planarization film 605 may be formed of an insulator. For example, the planarization film 605 may include an inorganic material, an organic material, or a combination of organic/inorganic materials, may be formed in a single layer or a multilayer structure, and may be formed via various deposition methods. In some embodiments, the planarization film 605 may include at least one of a polyacrylate resin, an epoxy resin, a phenol resin, a polyamide resin, a polyimide resin, an unsaturated polyester resin, a polyphenylene sulfide resin, and benzocyclobutene (BCB).

However, the embodiment according to the present disclosure is not limited to the above-described structure, and in some cases, any one of the interlayer insulating film 604 and the planarization film 605 may be omitted.

The first electrode 21 may be arranged on the upper portion of the interlayer insulating film 605 and may be electrically connected to the extremely small-sized LED element 40. For example, the first electrode 21 may include a plurality of first electrodes 21 that may be arranged in an upper portion of the interlayer insulating film 605. The plurality of first electrodes 21 may be spaced apart from each other with a designated gap therebetween.

In addition, the first electrode 21 according to an embodiment may be electrically connected to the first drain electrode 613 and may receive power. In this case, the first drain electrode 613 may be connected to the first electrode 21 via a via hole exposing a portion of the first drain electrode 613.

In addition, the first electrode 21 according to the embodiment may include at least one metal of Al, titanium (Ti), In, Au, and Ag or at least one transparent material of Indium Tin Oxide (ITO), zinc oxide (ZnO): Al, and Carbon Nanotube (CNT) -conductive polymer composite. When the first electrode 21 includes at least two types of materials, the first electrode 21 according to an embodiment may have a structure in which two or more different types of materials are stacked.

The second electrode 22 may be arranged in an upper portion of the interlayer insulating film 605 and may be electrically connected to the extremely small-sized LED element 40. For example, the second electrode 22 may have a circular shape extending in a circumferential direction around the first electrode 21. In this case, the first electrode 21 and the second electrode 22 may be arranged to be spaced apart from each other with a prescribed gap therebetween, for example, as shown in fig. 4B with a first separation distance D therebetween₁。

In addition, the second electrode 22 according to the embodiment may include a plurality of second electrodes 22, and the plurality of second electrodes 22 may be disposed in an upper portion of the base substrate 10. The plurality of second electrodes 22 may be spaced apart from each other with a designated gap therebetween. In addition, the second electrodes 22 according to the embodiment may be connected to each other via an electrode line 220 as shown in fig. 2A. In this case, the power wiring 630 may be electrically connected to the second electrode 22 via the through hole, and thus, the second electrode 22 may receive the same voltage power from the power wiring 630. For example, a planarization film 640 for planarizing the surface of the power supply wiring 630 may be arranged below the power supply wiring 630. However, the planarization film 640 is not a necessary component and may be omitted as needed.

In addition, the second electrode 22 according to the embodiment may include at least one metal of Al, Ti, In, Au and Ag or at least one transparent material of ITO, ZnO: Al and CNT-conductive polymer composition. When the second electrode 22 includes at least two materials, the second electrode 22 according to an embodiment may have a structure in which two or more different types of materials are stacked. For example, the materials included in the first electrode 21 and the second electrode 22 may be the same as or different from each other.

According to the embodiment, the extremely small-sized LED element 40 as a light emitting element that emits light may have various shapes such as a cylindrical shape or a rectangular parallelepiped. As shown in fig. 3, the very small-sized LED element 40 according to the embodiment may include a first electrode layer 410, a second electrode layer 420, a first semiconductor layer 430, a second semiconductor layer 440, and an active layer 450 disposed between the first semiconductor layer 430 and the second semiconductor layer 440. For example, the first electrode layer 410, the first semiconductor layer 430, the active layer 450, the second semiconductor layer 440, and the second electrode layer 420 may be sequentially stacked along the length direction of the very small-sized LED element 40. Further, according to an embodiment, the length T of the extremely small-sized LED element 40 may be about 2 to 5 μm, but the present disclosure is not limited thereto.

Each of the first electrode layer 410 and the second electrode layer 420 may be an ohmic contact electrode. However, the first electrode layer 410 and the second electrode layer 420 are not limited thereto, and each of the first electrode layer 410 and the second electrode layer 420 may be a Schottky (Schottky) contact electrode. Each of the first electrode layer 410 and the second electrode layer 420 may include a conductive metal. For example, each of the first electrode layer 410 and the second electrode layer 420 may include at least one metal of Al, Ti, In, Au, and Ag. For example, each of the first electrode layer 410 and the second electrode layer 420 may include the same material. As another example, the first electrode layer 410 and the second electrode layer 420 may include different materials from each other.

The first semiconductor layer 430 according to an embodiment may include, for example, an n-type semiconductor layer. For example, when the extremely small-sized LED element 40 is a blue light emitting element, the n-type semiconductor layer may include a compound having the chemical formula In_xAl_yGa_1-x-yN (0. ltoreq. x.ltoreq.1, 0. ltoreq. y.ltoreq.1, 0. ltoreq. x + y. ltoreq.1), for example, one of InAlGaN, GaN, AlGaN, InGaN, AlN, and InN, and the N-type semiconductor layer may be doped with a conductive dopant (e.g., silicon (Si), Ge, or Sn), but the disclosure is not limited thereto. Further, the extremely small-sized LED element 40 is not limited to the blue light emitting element, and when the light emission color of the extremely small-sized LED element 40 is not blue, the extremely small-sized LED element 40 may include different types of light emission colors in the n-type semiconductor layerGroup III-V semiconductor material of (a). However, the present disclosure is not limited thereto, and the first electrode layer 410 as an ohmic contact electrode may not be an essential component. In this case, the first semiconductor layer 430 may be connected to the first electrode 21.

The second semiconductor layer 440 according to an embodiment may include, for example, a p-type semiconductor layer. For example, when the extremely small-sized LED element 40 is a blue light emitting element, the p-type semiconductor layer may include a compound having the chemical formula In_xAl_yGa_1-x-yN semiconductor material, for example, one of InAlGaN, GaN, AlGaN, InGaN, AlN, and InN, the p-type semiconductor layer may be doped with a second conductive dopant, for example, magnesium (Mg). However, the present disclosure is not limited thereto, and the second electrode layer 420 as an ohmic contact electrode may not be an essential component. In this case, the second semiconductor layer 440 may be connected to the second electrode 22.

The active layer 450 may be disposed between the first semiconductor layer 430 and the second semiconductor layer 440, and may have, for example, a single or multiple quantum well structure. For example, a clad layer (not shown) doped with a conductive dopant may be disposed in an upper and/or lower portion of the active layer 450, and the clad layer doped with a conductive dopant may be implemented as an AlGaN layer or an InAlGaN layer. In addition, a material such as AlGaN or InAlGaN may also be included in the active layer 450. When an electric field is applied to the active layer 450, light may be generated due to the combination of electron-hole pairs, and the position of the active layer 450 may vary according to the type of LED element. Further, the extremely small-sized LED element 40 is not limited to the blue light emitting element, and when the light emission color of the extremely small-sized LED element 40 is not blue, the extremely small-sized LED element 40 may include different types of group III to group V semiconductor materials in the active layer 450. According to the present disclosure, the first and second semiconductor layers 430 and 440 and the active layer 450 may be included in the very small-sized LED element 40, but the present disclosure is not limited thereto. For example, the very small-sized LED element 40 may further include a fluorescent layer, an active layer, a semiconductor layer, and/or an electrode layer in upper and lower portions of the first semiconductor layer 430 and the second semiconductor layer 440.

In addition, the very small-sized LED element 40 according to the embodiment may further include an insulating film 470 covering an outer surface of the active layer 450. For example, the insulating film 470 may cover the side surface of the active layer 450, and thus, may prevent an electrical short that may be generated when the active layer 450 contacts the first electrode 21 or the second electrode 22. In addition, the insulating film 470 can prevent a decrease in light emission efficiency by protecting the outer surface of the extremely small-sized LED element 40 including the active layer 450.

The solvent 50 may be used without limitation as long as the solvent 50 is easily evaporated and does not cause physical and chemical damage to the extremely small-sized LED element 40, wherein the solvent 50 is a moving medium for activating diffusion and movement of the extremely small-sized LED element 40 according to the embodiment. For example, the solvent 50 may be one of acetone, water, alcohol, or toluene, but the present disclosure is not limited thereto.

According to the embodiment of the present disclosure, the solvent 50 may be put into the extremely small-sized LED element 40 at a designated weight ratio. For example, when the solvent 50 is thrown in an amount exceeding the range corresponding to the specified weight ratio, the excess amount of the solvent 50 may spread to an area other than the areas of the first and second electrodes 21 and 22 desired for the extremely small-sized LED elements 40, and thus the number of the extremely small-sized LED elements 40 to be mounted in the mounting area according to the first and second electrodes 21 and 22 may be reduced. Further, when the solvent 50 is thrown in an amount smaller than the range corresponding to the specified weight ratio, a problem occurs in the movement or alignment of each extremely small-sized LED element 40.

As described above, a prescribed electric power can be applied to the first electrode 21 and the second electrode 22 via the first drain electrode 613 and the power supply wiring 630. For example, the first drain electrode 613 may be connected to and apply power to the first electrode 21, and the power supply line 630 may be connected to and apply power to the second electrode 22. Accordingly, an electric field E may be formed between the first electrode 21 and the second electrode 22. Here, power having a designated amplitude and period is applied to the first and second electrodes 21 and 22, respectively, by applying Alternating Current (AC) power having a designated amplitude and period to the first and second electrodes 21 and 22, respectively, or by repeatedly applying Direct Current (DC) power to the first and second electrodes 21 and 22, respectively. Hereinafter, the self-alignment of the extremely small-sized LED element 40 will be described later in more detail, wherein the self-alignment of the extremely small-sized LED element 40 may be performed by an electric field E formed by applying a specified electric power to the first electrode 21 and the second electrode 22.

Fig. 4A is a perspective view of the pixel structure 1 before a voltage is applied to the first electrode 21 and the second electrode 22 according to an embodiment. Fig. 4B is a perspective view of the pixel structure 1 according to the embodiment. Fig. 4C is a perspective view of the pixel structure 1 after applying a voltage to the first electrode 21 and the second electrode 22 according to an embodiment. Fig. 4D is a perspective view of the pixel structure 1 according to the embodiment.

Since the extremely small-sized LED element 40 according to the embodiment may have an extremely small nano-size, it may be difficult to physically or directly connect the extremely small-sized LED element 40 to the first and second electrodes 21 and 22. Referring to fig. 4A, the very small-sized LED element 40 according to the embodiment may be thrown into the first and second electrodes 21 and 22 in a solution state where the very small-sized LED element 40 is mixed in the solvent 50. Here, when the first electrode 21 and the second electrode 22 are not supplied with electric power, the plurality of extremely small-sized LED elements 40 may float in the solution and may be arranged only along the outline of the first electrode 21 and the second electrode 22 or adjacent to each other. Further, when the very small-sized LED element 40 according to the embodiment is formed in a cylindrical shape, the very small-sized LED element 40 may move on the first and second electrodes 21 and 22 while rotating due to shape characteristics, and thus, the very small-sized LED element 40 may not be simultaneously connected to the first and second electrodes 21 and 22 by a self-alignment method.

Referring to fig. 2A, 2B and 4B, electric forces of different voltages may be applied to the first electrode 21 and the second electrode 22, respectively, according to an embodiment, and thus a specified electric field E may be formed between the first electrode 21 and the second electrode 22. For example, as described above, when AC power or DC power having a designated amplitude and period is repeatedly applied to the first electrode 21 and the second electrode 22 through the first drain electrode 613 and the power source wiring 630 several times, a radial first electric field E according to a potential difference of the first electrode 21 and the second electrode 22 may be formed between the first electrode 21 and the second electrode 22₁. Here, the first electric field E₁May be the same as the firstThe potential difference between the electrode 21 and the second electrode 22 is proportional and may be the first separation distance D between the first electrode 21 and the second electrode 22₁In inverse proportion. For example, a first separation distance D between the first electrode 21 and the second electrode 22₁May be about 1 μm or more and about 7 μm or less, and the voltage difference between the first electrode 21 and the second electrode 22 may be about 10V or more and about 50V or less, but the present disclosure is not limited thereto.

Referring to fig. 4C and 4D, when power is supplied to the first and second electrodes 21 and 22, the very small-sized LED element 40 according to the embodiment may pass through the first electric field E formed by the potential difference between the first and second electrodes 21 and 22₁Is self-aligned between the first electrode 21 and the second electrode 22. As described above, the first electric field E may be formed in the radial direction around the first electrode 21 due to the potential difference of the first electrode 21 and the second electrode 22₁Can pass through the first electric field E₁The inductance of (a) induces charge asymmetrically to the very small size LED element 40. Therefore, the extremely small-sized LED element 40 can follow the first electric field E₁Self-aligned between the first electrode 21 and the second electrode 22. Here, the connectors (e.g., the first electrode layer 410 and the second electrode layer 420) of the very small-sized LED element 40 may be arranged to simultaneously contact the first electrode 21 and the second electrode 22, respectively, and thus, the very small-sized LED element 40 may be electrically connected to the first electrode 21 and the second electrode 22. Since the extremely small-sized LED elements 40 according to the embodiment are self-aligned between the first and second electrodes 21 and 22 by the inductance of the electric field E formed by the potential difference of the first and second electrodes 21 and 22, the number of the extremely small-sized LED elements 40 connected to the first and second electrodes 21 and 22 may increase as the intensity of the electric field E increases. Here, the strength of the electric field E may be proportional to the potential difference between the first electrode 21 and the second electrode 22, and may be proportional to the first separation distance D between the first electrode 21 and the second electrode 22₁In inverse proportion.

Hereinafter, in order to form a pixel region where a plurality of extremely small-sized LED elements 40 are sufficiently mounted, an insulating process (not shown) may be performed, wherein the insulating process insulates the remaining region except for the region where the first and second electrodes 21 and 22 of the extremely small-sized LED elements 40 are sufficiently mounted. Accordingly, the pixel structure 1 including the plurality of first electrodes 21 and second electrodes 22 may include a plurality of pixel regions.

According to the method of driving the extremely small-sized LED element 40, a display device including a plurality of extremely small-sized LED elements 40 can be classified into a passive matrix type display device and an active matrix type display device. For example, when the display device is implemented in an active matrix type, as in the above-described embodiment, the pixel structure 1 may include the first thin film transistor TFT1 and the second thin film transistor TFT2, the first thin film transistor TFT1 as a driving transistor that controls the amount of current supplied to the extremely small-sized LED element 40, and the second thin film transistor TFT2 as a switching transistor that transmits a data voltage to the first thin film transistor TFT 1. Recently, an active matrix type display device that selectively turns on unit pixels according to resolution, contrast, and operation speed of a viewpoint is mainly used, but the present disclosure is not limited thereto. By using the electrode arrangement of the present disclosure, a passive matrix type display device in which pixels are turned on in groups is also possible.

As described above, the pixel structure 1 according to the embodiment can align and connect the plurality of extremely small-sized LED elements 40, which are nano-sized and independently manufactured, between the first electrode 21 and the second electrode 22 by using the electric field E radially formed between the first electrode 21 and the second electrode 22, and therefore, the difficulty of bonding the extremely small-sized LED elements 40 with the extremely small-sized first electrode 21 and the second electrode 22 in one-to-one correspondence can be solved. Further, although the typical cylindrical extremely small-sized LED element 40 is used, since the alignment between the extremely small-sized LED element 40 and the first and second electrodes 21 and 22 is maintained, the defect rate of the pixel structure 1 can be minimized. Further, the extremely small-sized LED elements 40 can be collectively arranged and connected to a desired mounting region including the first electrode 21 and the second electrode 22 which are different from each other.

Fig. 5A is a perspective view of a pixel structure 1 according to another embodiment. Fig. 5B is a cross-sectional view taken along line B-B' of the pixel structure 1 of fig. 5A. Referring to fig. 5A and 5B, a pixel structure 1 according to another embodiment may include a first electrode 21 disposed in an upper portion of a base substrate 10, a second electrode 22 including a second-1 electrode 22-1 and a second-2 electrode 22-2, a plurality of very small-sized LED elements 40 disposed between the first electrode 21, the second-1 electrode 22-1 and the second-2 electrode 22-2, and a solvent 50 in which the very small-sized LED elements 40 are mixed. Repeated descriptions will be omitted for the sake of brevity.

The second electrode 22 may include a second-1 electrode 22-1 and a second-2 electrode 22-2 arranged spaced apart from each other. The second-1 electrode 22-1 and the second-2 electrode 22-2 may be arranged in an upper portion of the interlayer insulating film 605 and may be electrically connected to the extremely small-sized LED element 40. For example, each of the second-1 electrode 22-1 and the second-2 electrode 22-2 may have a semicircular shape extending in a circumferential direction around the first electrode 21.

Further, the second-1 electrode 22-1 and the second-2 electrode 22-2 according to the embodiment may include a plurality of second-1 electrodes 22-1 and second-2 electrodes 22-2, and the plurality of second-1 electrodes 22-1 and second-2 electrodes 22-2 may be disposed in an upper portion of the interlayer insulating film 605 to be spaced apart from each other with a designated gap therebetween. In addition, the second-1 electrodes 22-1 according to the embodiment may be connected to each other via the first electrode lines 220-1, and the second-2 electrodes 22-2 according to the embodiment may be connected to each other via the second electrode lines 220-2. As shown in fig. 5B, the power wiring 630 may be connected to each of the second-1 electrode 22-1 and the second-2 electrode 22-2 via a via hole, and thus, power of a first voltage may be supplied to the second-1 electrode 22-1, and power of a second voltage may be supplied to the second-2 electrode 22-2. The magnitude of the first voltage may be different from the magnitude of the second voltage.

In addition, the second-1 electrode 22-1 and the second-2 electrode 22-2 according to the embodiment may include at least one metal of Al, Ti, In, Au, and Ag, or at least one transparent material of ITO, ZnO: Al, and CNT-conductive polymer composition. When each of the second-1 electrode 22-1 and the second-2 electrode 22-2 includes at least two materials, each of the second-1 electrode 22-1 and the second-2 electrode 22-2 according to the embodiment may have a structure in which two or more different types of materials are stacked. According to an embodiment, the second-1 electrode 22-1 and the second-2 electrode 22-2 may include different materials and the same material.

Fig. 6A is a perspective view of the pixel structure 1 before a voltage is applied to the first electrode 21 and the second electrode 22 according to another embodiment. Fig. 6B is a perspective view of a pixel structure 1 according to another embodiment. Fig. 6C is a perspective view of the pixel structure 1 after applying a voltage to the first electrode 21 and the second electrode 22 according to another embodiment. Fig. 6D is a perspective view of a pixel structure 1 according to another embodiment.

As shown in fig. 4A to 4D, the pixel structure 1 according to the embodiment can align and connect a plurality of very small-sized LED elements 40, which are nano-sized and independently manufactured, between the first electrode 21 and the second electrode 22 by using an electric field E formed radially between the first electrode 21 and the second electrode 22. Therefore, when the first electric field E is radially formed between the first electrode 21 and the second electrode 22 as shown in fig. 4C₁At this time, the extremely small-sized LED element 40 may be aligned between the first electrode 21 and the second electrode 22, but since the same voltage is applied to the second electrode 22, a separate electric field E is not formed between the plurality of second electrodes 22. Therefore, the extremely small-sized LED elements 40 arranged between the second electrodes 22 may be arranged along the outline of the second electrodes 22 or adjacent to each other.

Referring to fig. 6A, the very small-sized LED element 40 according to the embodiment may be put into the first electrode 21, the second-1 electrode 22-1, and the second-2 electrode 22-2 in a solution state in which the very small-sized LED element 40 is mixed in the solvent 50. When no electric power is applied to the first electrode 21, the second-1 electrode 22-1, and the second-2 electrode 22-2, the plurality of very small-sized LED elements 40 may float in the solution and may be arranged only along the contour of the first electrode 21, the second-1 electrode 22-1, and the second-2 electrode 22-2 or adjacent to each other. Referring to fig. 6B, power may be applied to each of the first electrode 21, the second-1 electrode 22-1, and the second-2 electrode 22-2 according to the embodiment, and thus a specified electric field E may be formed between each set of the first electrode 21 and the second-1 electrode 22-1, the first electrode 21 and the second-2 electrode 22-2, and the second-1 electrode 22-1 and the second-2 electrode 22-2. For example, as described above, when electricity is applied to the first electrode 21, the second-1 electrode 22-1 and the second-2 electrodeWhen the pole 22-2 repeatedly applies AC power or DC power having a designated amplitude and period several times, a first-1 electric field E according to the potential difference of the first electrode 21 and the second electrode 22-1 may be formed between the first electrode 21 and the second electrode 22-1₁₁A first-2 electric field E according to the potential difference of the first electrode 21 and the second electrode 22-2 can be formed between the first electrode 21 and the second electrode 22-2₁₂And a second electric field E according to a potential difference of the second-1 electrode 22-1 and the second-2 electrode 22-2 may be formed between the second-1 electrode 22-1 and the second-2 electrode 22-2₂。

Referring to fig. 6C and 6D, the very small-sized LED element 40 according to the embodiment may pass the first-1 electric field E formed by the potential difference of the first electrode 21 and the second-1 electrode 22-1₁₁Is self-aligned between the first electrode 21 and the second-1 electrode 22-1. According to the embodiment, as described above, when the electric power having the designated voltage difference is supplied to the first electrode 21 and the second-1 electrode 22-1, the first-1 electric field E may be formed between the first electrode 21 and the second-1 electrode 22-1 by the potential difference of the first electrode 21 and the second-1 electrode 22-1₁₁. Thus, charge can pass through the first-1 electric field E₁₁Is asymmetrically induced into the very small size LED element 40, the very small size LED element 40 may follow the first-1 electric field E₁₁Self-aligned between the first electrode 21 and the second-1 electrode 22-1. Here, the connectors (e.g., the first electrode layer 410 and the second electrode layer 420) of the very small-sized LED element 40 may be arranged to simultaneously contact the first electrode 21 and the second-1 electrode 22-1, respectively, and thus, the very small-sized LED element 40 may be electrically connected to the first electrode 21 and the second-1 electrode 22-1.

Further, the extremely small-sized LED element 40 can pass through the first-2 electric field E formed by the potential difference of the first electrode 21 and the second-2 electrode 22-2₁₂Is self-aligned between the first electrode 21 and the second-2 electrode 22-2. Due to the first-2 electric field E₁₂Is formed by the first electrode 21 and the second-2 electrode 22-2, and charges are passed through the first-2 electric field E₁₂Is asymmetrically induced to the very small-sized LED element 40, and self-alignment of the very small-sized LED element 40 by the very small-sized LED element 40 through the first electrode 21 and the second-1 electrode 22-1The self-alignment method is substantially the same, and thus, a repetitive description will be omitted for the sake of brevity.

According to the embodiment, as described above, the first-1 electric field E formed by the potential difference of the first electrode 21 and the second-1 electrode 22-1 may be formed radially around the first electrode 21₁₁And a first-2 electric field E formed by a potential difference of the first electrode 21 and the second-2 electrode 22-2₁₂. Since the voltages of the power applied to each of the second-1 electrode 22-1 and the second-2 electrode 22-2 are different from each other, as long as the first-1 separation distance D between the first electrode 21 and the second-1 electrode 22-1 is provided₁₁A first-2 separation distance D from the first electrode 21 and the second-2 electrode 22-2₁₂Are identical to each other, a first-1 electric field E₁₁And a first-2 electric field E₁₂Will be different from each other. Therefore, in order to form the first-1 electric field E between the first electrode 21 and the second-1 and-2 electrodes 22-1 and 22-2₁₁And a first-2 electric field E₁₂Consistently, the first-1 separation distance D may be formed differently₁₁And a first-2 separation distance D₁₂. For example, when a first power voltage applied to the second-1 electrode 22-1 is greater than a second power voltage applied to the second-2 electrode 22-2, the first-1 separation distance D₁₁May be greater than the first-2 separation distance D₁₂Thus, the first-1 electric field E can be uniformly formed₁₁And a first-2 electric field E₁₂Combined first electric field E₁. However, the present disclosure is not limited thereto, the first-1 separation distance D₁₁And a first-2 separation distance D₁₂May be identical to each other. For example, when the length T of the extremely small-sized LED element 40 is 2 μm to 5 μm as shown in FIG. 3, the first-1 separation distance D₁₁And a first-2 separation distance D₁₂May each be about 1 μm or more and about 7 μm or less, and the voltage difference between the first electrode 21 and the second-1 electrode 22-1 and the voltage difference between the first electrode 21 and the second-2 electrode 22-2 may be about 10V or more and about 50V or less.

Further, when the extremely small-sized LED element 40 is disposed between the second-1 electrode 22-1 and the second-2 electrode 22-2, the extremely small-sized LED element 40 can pass through the electric potential by the second-1 electrode 22-1 and the second-2 electrode 22-2Second electric field E of differential formation₂Moves to one side of the second-1 electrode 22-1 or the second-2 electrode 22-2. According to an embodiment, when a voltage higher than that of the second-2 electrode 22-2 is applied to the second-1 electrode 22-1 and no voltage is applied to the first electrode 21, a first-1 electric field E may be formed between the first electrode 21 and the second-1 electrode 22-1₁₁A first-2 electric field E may be formed between the first electrode 21 and the second-2 electrode 22-2₁₂And a second electric field E may be formed from the second-1 electrode 22-1 toward the second-2 electrode 22-2₂. Here, the first-1 electric field E₁₁May be larger than the first-2 electric field E₁₂First-2 electric field E₁₂May be larger than the second electric field E₂。

For example, when the extremely small-sized LED element 40 is disposed between the second-1 electrode 22-1 and the second-2 electrode 22-2, electric charges may pass through the second electric field E formed between the second-1 electrode 22-1 and the second-2 electrode 22-2₂Is induced asymmetrically to the very small size LED element 40. The very small size LED element 40 disposed between the second-1 electrode 22-1 and the second-2 electrode 22-2 may follow the second electric field E₂To the second-2 electrode 22-2. Thereafter, the very small-sized LED element 40 may pass through the first-2 electric field E formed by the first electrode 21 and the second-2 electrode 22-2₁₂Self-aligned between the first electrode 21 and the second-2 electrode 22-2.

As described above, the pixel structure 1 according to the embodiment can remove the region where the electric fields E are balanced with each other by using the second-1 electrode 22-1 and the second-2 electrode 22-2 to which different voltages are applied, respectively, and thus all the very small-sized LED elements 40 arranged in the pixel can be aligned with and connected to each other among the first electrode 21, the second-1 electrode 22-1, and the second-2 electrode 22-2.

Fig. 7 is a conceptual diagram of a display device 1000 according to an embodiment.

Referring to fig. 7, the display device 1000 may include a plurality of pixel structures 1 according to the above-described embodiments and a driving circuit connected to the pixel structures 1.

The pixel structure 1 may be arranged in the display area DA of the display device 1000. The driving circuit may be disposed in a non-display area disposed along the outline of the display area DA of the display device 1000. The driving circuit may include a data driving circuit 7 and a gate driving circuit 8.

The length of the sides of each pixel structure 1 may be about 600 μm or less. When the pixel structures 1 form sub-pixels, the length of the sides of each pixel structure 1 may be about 200 μm or less. The side of each pixel structure 1 may be the short side of each pixel structure 1. However, the size of the pixel structure 1 is not limited thereto, and may be changed according to the size and the number of pixels required for the display device 1000.

The data driving circuit 7 may include a plurality of source driving Integrated Circuits (ICs) and may drive the data lines DL. The gate driving circuit 8 may include at least one gate driving IC and may supply a scan pulse to the gate lines GL.

It is to be understood that the embodiments described herein are for purposes of description only and not limitation. Descriptions of features or aspects within each embodiment should generally be understood to apply to other similar features or aspects in other embodiments.

Although one or more embodiments have been described with reference to the accompanying drawings, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope defined by the following claims.