Patent Description:
With the development of multimedia, display devices are becoming more important. In response to the development, various types of display devices, such as organic light emitting diode (OLED) display devices, liquid crystal display (LCD) devices, and the like, are being used.

A device for displaying an image of a display device includes a display panel such as an OLED panel or an LCD panel. Among the above panels, a light emitting display panel may include a light emitting element. For example, an LED includes an OLED using an organic material as a fluorescent material, and an inorganic LED using an inorganic material as a fluorescent material.

The inorganic LED using an inorganic semiconductor as a fluorescent material has durability in a high temperature environment and has an advantage of high efficiency of blue light as compared with the OLED. Further, even in a manufacturing process which has been pointed out as a limitation of the conventional inorganic LED element, a transfer method using dielectrophoresis (DEP) has been developed. Therefore, research is being carried out on inorganic LEDs having excellent durability and excellent efficiency as compared with OLEDs.

<CIT> describes a display apparatus including a substrate, a first electrode on the substrate, the first electrode including a first portion that has a flat upper surface and a second portion that protrudes from the first portion and has an inclined surface, a second electrode facing the first electrode in parallel on the substrate, the second electrode including a first portion that has a flat upper surface and a second portion that protrudes from the first portion and has an inclined surface, and a plurality of light-emitting devices separate from each other on the first electrode and the second electrode, the light-emitting devices each having a first end contacting the upper surface of the first portion of the first electrode and a second end contacting the upper surface of the first portion of the second electrode.

<CIT> describes a display including a nano-scale LED and a method for manufacturing the same. In detail, nano-scale LED devices, each of which has a nano unit, are connected to nano-scale electrodes without electrical short-circuit to overcome a limitation in which it is difficult to allow nano-scale LED devices according to the related art to stand up and be coupled to electrodes and a limitation in which it is difficult to allow the nano-scale LED devices to be one-to-one coupled to the nano-scale electrodes different from each other, thereby realizing a display including the nano-scale LEDs. Also, the display may have superior light extraction efficiency and prevent defective pixels and the defect of the whole display due to the defects of the nano-scale LED devices, which may rarely occur, from occurring to minimize the defects of the display including the nano-scale LEDs and maintain its original function.

<CIT> describes an electro-fluidic assembly process for integration of an electronic device or component onto a substrate which comprises: disposing components within a carrier fluid; attracting the components to an alignment sites on the substrate by means of electrophoresis or dielectrophoresis; and aligning the components within the alignment site by means of energy minimization. The substrate comprises: a biased backplane layer, a metal plane layer having one or more alignment sites, a first insulating layer disposed between the backplane layer and the metal plane layer, and a second insulating layer, e.g., benzocyclobute, having a recess disposed therein, wherein the second insulating layer is on the surface of the metal plane layer opposite from the first insulating layer and wherein the recess is in communication with the alignment site.

<NPL>, describes a flexible approach for chip to wafer high-accurate alignment and bonding developed using a self-assembled monolayer (SAM). In this approach, a hydrophobic SAM, FDTS (CF<NUM>(CF<NUM>)<NUM>(CH<NUM>)<NUM>SiCl<NUM>), is successfully patterned by lift-off process on an oxidized silicon wafer to define the binding-sites. A certain volume of H<NUM>O (µ/mm<NUM>) is dropped and then spread on the non-coated hydrophilic SiO<NUM> binding-sites for self-alignment of various microelectromechanical systems (MEMS) and IC chips by capillary force of H<NUM>O. Our results demonstrate that reasonably high alignment speed (in milliseconds) and excellent alignment accuracy ( ≤ <NUM>) are achieved when the difference in the measured contact angle between hydrophobic FDTS and hydrophilic binding-sites is >;<NUM>°. It is also found that the hydrophilic frame at the edge of each binding-site is effective in achieving successful self-alignment, while a super fine pattern at the center of the binding-site can be used to control the bonding strength. The effects of the Au/Cr thin film pattern on self-alignment are studied and discussed in this paper to enable the application of the above approach in various MEMS-IC integration processes, especially for low-cost mass production of wireless sensor nodes.

The present invention is directed to providing a method of manufacturing a display device, which includes forming a spreading prevention layer on an electrode to spray a solvent, in which light emitting elements are dispersed, on the spreading prevention layer, thereby arranging the light emitting elements.

The present invention is also directed to providing a display device including light emitting elements sprayed on the spreading prevention layer and disposed between electrodes.

It should be noted that objects of the present invention are not limited to the above-described objects, and other objects of the present invention will be apparent to those skilled in the art from the following descriptions.

According to a first aspect of the disclosure, there is provided a display device according to the appended claims.

According to an example, a display device comprises: a substrate in which a first area and a second area, which is an area other than the first area, are defined, a first electrode and a second electrode disposed and at least partially spaced apart from each other in the first area on the substrate, a coating layer disposed to cover at least a portion of each of the first electrode and the second electrode on the substrate, and at least one light emitting element disposed between the first electrode and the second electrode in the first area, wherein the coating layer includes an opening exposing at least a portion of each of the first electrode and the second electrode and includes a first coating layer which is disposed in an area except for the opening and which includes a hydrophobic material.

The first coating layer may be disposed to at least overlap the first area, and the light emitting element may be disposed in an area in which the opening is not disposed on the first coating layer.

The first coating layer may be disposed to cover the first electrode and the second electrode which are disposed in the first area, and the opening may be disposed on the first coating layer and includes a first opening exposing at least a portion of the first electrode and the second electrode of the first area.

The display device may further comprise: a first contact electrode in contact with the first electrode exposed through the first opening, and a second contact electrode in contact with the second electrode exposed through the first opening, wherein the first contact electrode may be in contact with one end portion of the light emitting element and the second contact electrode may be in contact with the other end portion thereof.

The first coating layer may be disposed in a gap region in which the first electrode and the second electrode are spaced apart from each other and partially overlap facing side surfaces of the first electrode and the second electrode.

The first coating layer may include at least one coating pattern, and the coating pattern may be disposed on a first side surface at which the first electrode is opposite to the second electrode and disposed on a second side surface at which the second electrode is opposite to the first electrode.

At least a portion of each of the first electrode and the second electrode may be disposed in the second area, and the first coating layer may be disposed to cover the first electrode and the second electrode in the second area.

The coating layer may include a second coating layer disposed in the first area, and the light emitting element may be disposed on the second coating layer.

The first coating layer may include a polymer containing fluorine.

The second coating layer may be disposed to cover the first electrode and the second electrode which are disposed in the first area, and the opening may be disposed on the second coating layer and further include a second opening exposing at least a portion of each of the first electrode and the second electrode of the first area.

The second coating layer may be disposed in a gap region between the first electrode and the second electrode which are disposed in the first area.

The second coating layer may be disposed to partially overlap facing side surfaces of the first electrode and the second electrode.

According to another embodiment, a method of manufacturing a display device comprises: preparing a target substrate and a first electrode and a second electrode which are spaced apart from each other on the target substrate, forming a coating layer which is disposed on at least a partial area of the target substrate and which covers at least a portion of each of the first electrode and the second electrode, and spraying an ink including a light emitting element on the coating layer covering the first electrode and the second electrode and landing the light emitting element between the first electrode and the second electrode.

The coating layer includes a material having a first polarity, and the ink includes a solvent having a second polarity opposite to the first polarity.

The first polarity is hydrophobic and the second polarity is hydrophilic, and the coating layer may contain a fluorine-based polymer.

The ink may be sprayed onto the coating layer on the first electrode and the second electrode, and the ink sprayed onto the coating layer may have a contact angle of <NUM> degrees or more between the ink and the coating layer.

The landing of the light emitting element may include applying alternating-current (AC) power to the first electrode and the second electrode to form an electric field in the ink, and arranging the light emitting element between the first electrode and the second electrode due to the electric field.

The details of other embodiments are included in the detailed description and the accompanying drawings.

In accordance with a method of manufacturing a display device according to an embodiment, a coating layer having a polarity opposite, being hydrophobic, to a polarity, being hydrophilic, of an ink including a light emitting element can be formed, and the coating layer can prevent the ink from spreading from an area in which the ink is sprayed. Consequently, in a manufacturing process of the display device, a position of the ink can be maintained at a position in the area in which the ink is sprayed, and the light emitting element can be disposed between electrodes in a specific area.

In addition, in accordance with a display device according to an embodiment, the number of light emitting elements disposed in an alignment area can be increased to improve a process yield and light emission reliability for each pixel.

The effects according to the embodiments are not limited by the contents exemplified above, and more various effects are included in this disclosure.

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

It will also be understood that when a layer is referred to as being "on" another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. The same reference numbers indicate the same components throughout the specification.

It will be understood that, although the terms "first," "second," etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For instance, a first element discussed below could be termed a second element without departing from the teachings of the present invention. Similarly, the second element could also be termed the first element.

<FIG> is a plan view illustrating a display device according to one embodiment.

Referring to <FIG>, a display device <NUM> includes a plurality of pixels PX. Each pixel PX includes one or more light emitting elements <NUM>, which emit light in a specific wavelength range, to display a specific color.

Each pixel PX may include a first sub-pixel PX1, a second sub-pixel PX2, and a third sub-pixel PX3. The first sub-pixel PX1 may emit light of a first color, the second sub-pixel PX2 may emit light of a second color, and the third sub-pixel PX3 may emit light of a third color. The first color may be a red color, the second color may be a green color, and the third color may be a blue color, but the present invention is not limited thereto, and the sub-pixels PXn may emit light of the same color. In addition, although each pixel PX has been illustrated as including three sub-pixels in <FIG>, the present invention is not limited thereto, and each pixel PX may include a larger number of sub-pixels.

Meanwhile, in this disclosure, terms "first," "second," and the like are used to refer to each of the components, but these are used to simply distinguish the components from each other and do not necessarily refer to a corresponding component. That is, the components defined as first, second, and the like are not necessarily limited to a specific structure or location and, in some cases, other numbers may be assigned to the components. Therefore, the number assigned to each component may be described through the drawings and the following description, and a first component mentioned below may be a second component within the technical idea of the present invention.

Each sub-pixel PXn of the display device <NUM> may include an area defined as an alignment area AA and an area defined as a non-alignment area NAA. The alignment area AA is defined as an area in which the light emitting elements <NUM> included in the display device <NUM> are disposed. The non-alignment area NAA may be an area other than the alignment area AA and defined as an area in which the light emitting elements <NUM> are not disposed and light is not emitted.

However, the definition of the alignment area AA is not limited thereto and may be defined as an area in which the light emitting elements <NUM> should be disposed. In other words, the alignment area AA in which the light emitting elements <NUM> should be aligned is defined on each pixel PX or each sub-pixel PXn, and in the manufacturing process of the display device <NUM>, the light emitting elements <NUM> may be disposed in the alignment area AA. In an example, the alignment area AA may include electrodes <NUM> and <NUM> of each sub-pixel PXn and may be defined as an area between the electrodes <NUM> and <NUM>.

The display device <NUM> includes a coating layer <NUM> disposed on at least a partial region of each pixel PX or each sub-pixel PXn. The coating layer <NUM> is disposed in the alignment area AA or the non-alignment area NAA of each sub-pixel PXn, and the coating layer <NUM> partially overlap the electrodes <NUM> and <NUM>. <FIG> illustrates that the coating layer <NUM> is disposed in each sub-pixel PXn to entirely cover the electrodes <NUM> and <NUM> and includes an opening 80P which exposes some region of each sub-pixel PXn. The coating layer <NUM> may include the alignment area AA and may be partially disposed even in the non-alignment area NAA. However, the present invention is not limited thereto.

As described below, in the manufacturing process of the display device <NUM>, the coating layer <NUM> distributes an ink S in which the light emitting elements <NUM> are dispersed to the electrodes <NUM> and <NUM> and applies an electric field to the ink S so that the light emitting elements <NUM> may be disposed on the electrodes <NUM> and <NUM>. The coating layer <NUM> according to one embodiment may perform a function of preventing the ink S sprayed on each pixel PX or each sub-pixel PXn from moving or spreading to an area other than a required alignment area AA. Owing to the coating layer <NUM>, the ink S may be sprayed into the required alignment area AA, and the light emitting elements <NUM> may be smoothly disposed on the electrodes <NUM> and <NUM>. A detailed description thereof will be made below.

The sub-pixel PXn of the display device <NUM> may include a plurality of banks <NUM>, a plurality of electrodes <NUM> and <NUM>, the light emitting elements <NUM>, and the coating layer <NUM>.

The plurality of electrodes <NUM> and <NUM> may be electrically connected to the light emitting elements <NUM> and may receive a predetermined voltage so as to allow the light emitting elements <NUM> to emit light. In addition, in order to align the light emitting elements <NUM>, at least a portion of each of the electrodes <NUM> and <NUM> may be utilized to form an electric field in the sub-pixel PXn.

The plurality of electrodes <NUM> and <NUM> includes a first electrode <NUM> and a second electrode <NUM>. In an example, the first electrode <NUM> may be a pixel electrode which is separated in each sub-pixel PXn, and the second electrode <NUM> may be a common electrode which is commonly connected along the sub-pixels PXn. One of the first electrode <NUM> and the second electrode <NUM> may be an anode electrode of the light emitting element <NUM>, and the other thereof may be a cathode electrode of the light emitting element <NUM>. However, the present invention is not limited thereto and the reverse of the above description may be possible.

The first electrode <NUM> and the second electrode <NUM> may include electrode stem portions <NUM> and <NUM> disposed to extend in a first direction X-axis and include electrode branch portions 21B and 22B extending and branching from the electrode stem portions <NUM> and <NUM> in a second direction Y-axis intersecting the first direction X-axis.

The first electrode <NUM> may include a first electrode stem portion <NUM> disposed to extend in the first direction X-axis, and at least one first electrode branch portion 21B branching from the first electrode stem portion <NUM> to extend in the second direction Y-axis.

Two ends of the first electrode stem portion <NUM> of any one pixel may be separated to be terminated between the sub-pixels PXn and disposed to be substantially collinear with a first electrode stem portion <NUM> of an adjacent sub-pixel PXn (e.g., a subpixel which is adjacent in the first direction X-axis) belonging to the same row. Thus, the first electrode stem portion <NUM> disposed in each sub-pixel PXn may apply different electrical signals to first electrode branch portions 21B, and the first electrode branch portions 21B may be driven separately.

The first electrode branch portion 21B branches from at least a portion of the first electrode stem portion <NUM> and is disposed to extend in the second direction Y-axis. The first electrode branch portion 21B may be terminated in a state of being separated from the second electrode stem portion <NUM> which is disposed opposite to the first electrode stem portion <NUM>.

The second electrode <NUM> may include the second electrode stem portion <NUM> which extends in the first direction X-axis and is disposed to be separated from and opposite to the first electrode stem portion <NUM>, and the second electrode branch portion 22B which branches from the second electrode stem portion <NUM> and is disposed to extend in the second direction Y-axis. However, one end portion of the second electrode stem portion <NUM> may extend to a plurality of adjacent sub-pixels PXn in the first direction X-axis. Thus, the two ends of the second electrode stem portion <NUM> of any one pixel may be connected to a second electrode stem portion <NUM> of an adjacent pixel PX among the pixels PX.

The second electrode branch portion 22B may be separated from and opposite to the first electrode branch portion 21B and terminated in a state of being separated from the first electrode stem portion <NUM>. That is, one end portion of the second electrode branch portion 22B may be connected to the second electrode stem portion <NUM>, and the other end portion thereof may be disposed in the sub-pixel PXn in a state of being separated from the first electrode stem portion <NUM>.

In the drawing, two first electrode branch portions 21B have been illustrated as being disposed and the second electrode branch portion 22B has been illustrated as being disposed between the two first electrode branch portions 21B, but the present invention is not limited thereto.

The plurality of banks <NUM> includes a third bank <NUM> disposed at a boundary between the sub-pixels PXn, and a first bank <NUM> and a second bank <NUM> which are disposed below the electrodes <NUM> and <NUM>. Although the first bank <NUM> and the second bank <NUM> are not illustrated in the drawing, the first bank <NUM> and the second bank <NUM> are disposed below the first electrode branch portion 21B and the second electrode branch portion 22B, respectively.

The third bank <NUM> may be disposed at a boundary between the sub-pixels PXn. End portions of the plurality of first electrode stem portions <NUM> may be separated from each other to be terminated based on the third bank <NUM>. The third bank <NUM> may extend in the second direction Y-axis and may be disposed at the boundary between the sub-pixels PXn disposed in the first direction X-axis. However, the present invention is not limited thereto, and the third bank <NUM> may extend in the first direction X-axis and may be disposed even at the boundary between the sub-pixel PXn disposed in the second direction Y-axis. The third bank <NUM> may include the same material as the first bank <NUM> and the second bank <NUM> and may be formed in substantially the same process.

Although not shown in the drawing, a first insulating layer <NUM> is disposed in each sub-pixel PXn to entirely cover each sub-pixel PXn including the first electrode branch portion 21B and the second electrode branch portion 22B. The first insulating layer <NUM> may protect each of the electrodes <NUM> and <NUM> and, simultaneously, insulate the electrodes <NUM> and <NUM> from each other so as not to be in direct contact with each other.

The plurality of light emitting elements <NUM> are disposed between the first electrode branch portion 21B and the second electrode branch portion 22B. One end portions of at least some of the plurality of light emitting elements <NUM> may be electrically connected to the first electrode branch portion 21B and the other end portions thereof electrically connected to the second electrode branch portion 22B.

The plurality of light emitting elements <NUM> may be separated from each other in the second direction Y-axis and disposed substantially parallel to each other. A separation gap between the light emitting elements <NUM> is not particularly limited. In some cases, the plurality of light emitting elements <NUM> may be disposed adjacent to each other to form a group, and a plurality of other light emitting elements <NUM> may be grouped in a state of being spaced at regular intervals from each other, may have a nonuniform density, and may be oriented and aligned in one direction.

The contact electrode <NUM> may be disposed on the first electrode branch portion 21B and the second electrode branch portion 22B. However, the contact electrode <NUM> may be substantially disposed on the first insulating layer <NUM>, and at least a portion of the contact electrode <NUM> may be in contact with or electrically connected to the first electrode branch portion 21B and the second electrode branch portion 22B.

A plurality of contact electrodes <NUM> may be disposed to extend in the second direction Y-axis and disposed to be separated from each other in the first direction X-axis. The contact electrode <NUM> may be in contact with at least one end portion of the light emitting element <NUM>, and the contact electrode <NUM> may be in contact with the first electrode <NUM> or the second electrode <NUM> to receive an electrical signal. Thus, the contact electrode <NUM> may transmit an electrical signal, which is transmitted from each of the electrodes <NUM> and <NUM>, to the light emitting element <NUM>.

The contact electrode <NUM> may include a first contact electrode 26a and a second contact electrode 26b. The first contact electrode 26a may be disposed on the first electrode branch portion 21B to be in contact with one end portion of the light emitting element <NUM>, and the second contact electrode 26b may be disposed on the second electrode branch portion 22B to be in contact with the other end portion thereof.

The first electrode stem portion <NUM> and the second electrode stem portion <NUM> may be electrically connected to a circuit element layer of the display device <NUM> through contact holes, for example, a first electrode contact hole CNTD and a second electrode contact hole CNTS. In the drawing, one second electrode contact hole CNTS has been illustrated as being formed in the second electrode stem portion <NUM> of each of the plurality of sub-pixels PXn. However, the present invention is not limited thereto, and in some cases, the second electrode contact hole CNTS may be formed in each sub-pixel PXn.

In addition, although not shown in the drawing, the display device <NUM> may include a second insulating layer <NUM> (see <FIG>) and a passivation layer <NUM> (see <FIG>) which are disposed to cover at least a portion of each of the electrodes <NUM> and <NUM> and the light emitting element <NUM>. An arrangement and structures thereof will be described below.

<FIG> is a schematic diagram illustrating the light emitting element <NUM> according to one embodiment.

The light emitting element <NUM> may be an LED. Specifically, the light emitting element <NUM> may be an inorganic LED having a micrometer unit or nanometer unit size and made of an inorganic material. The inorganic light emitting diode may be aligned between two electrodes in which polarity is formed by forming an electric field in a specific direction between the two electrodes facing each other. The light emitting element <NUM> may be aligned between two electrodes due to an electric field formed on the two electrodes.

The light emitting element <NUM> may include a semiconductor crystal doped with an arbitrary conductivity type (e.g., p-type or n-type) impurity. The semiconductor crystal may receive an electrical signal applied from an external power source and emit light in a specific wavelength range.

Referring to <FIG>, the light emitting element <NUM> according to one embodiment may include a first conductivity type semiconductor <NUM>, a second conductivity type semiconductor <NUM>, an active layer <NUM>, and an insulating film <NUM>. In addition, the light emitting element <NUM> according to one embodiment may further include at least one conductive electrode layer <NUM>. Although the light emitting element <NUM> has been illustrated as further including one conductive electrode layer <NUM> in <FIG>, the present invention is not limited thereto. In some cases, the light emitting element <NUM> may include a greater number of conductive electrode layers <NUM> or the conductive electrode layer <NUM> may be omitted. A description of the light emitting element <NUM>, which will be made below, may be identically applied even when the number of conductive electrode layers <NUM> is varied or another structure is further included.

The light emitting element <NUM> may have a shape extending in one direction. The light emitting element <NUM> may have a shape of nanorods, nanowires, nanotubes, or the like. In an embodiment, the light emitting element <NUM> may be a cylindrical shape or a rod shape. However, the shape of the light emitting element <NUM> is not limited thereto and may have various shapes such as a regular hexahedral shape, a rectangular parallelepiped shape, a hexagonal column shape, and the like. A plurality of semiconductors included in the light emitting element <NUM>, which will be described below, may have a structure in which the semiconductors are sequentially disposed or stacked in the one direction.

The light emitting element <NUM> according to one embodiment may emit light in a specific wavelength range. In an example, the active layer <NUM> may emit blue light having a central wavelength range ranging from <NUM> to <NUM>. However, the central wavelength range of the blue light is not limited to the above range, and it should be understood that the central wavelength range includes all wavelength ranges which can be recognized as a blue color in the art. Further, the light emitted from the active layer <NUM> of the light emitting element <NUM> is not limited thereto, and the light may be green light having a central wavelength range ranging from <NUM> to <NUM> or red light having a central wavelength range ranging from <NUM> to <NUM>.

To describe the light emitting element <NUM> in detail with reference to <FIG>, the first conductivity type semiconductor <NUM> may be an n-type semiconductor having, for example, a first conductivity type. For example, when the light emitting element <NUM> emits light in a blue wavelength range, the first conductivity type semiconductor <NUM> may include a semiconductor material having a chemical formula of InxAlyGa<NUM>-x-yN (<NUM>≤x≤<NUM>, <NUM>≤y≤<NUM>, and <NUM>≤x+y≤<NUM>). For example, the semiconductor material may be one or more among InAlGaN, GaN, AlGaN, InGaN, AlN, and InN which are doped with an n-type impurity. The first conductivity type semiconductor <NUM> may be doped with a first conductive dopant. For example, the first conductivity type dopant may be Si, Ge, Sn, or the like. In an example, the first conductivity type semiconductor <NUM> may be n-GaN doped with n-type Si. A length of the first conductivity type semiconductor <NUM> may range from <NUM> to <NUM>, but the present invention is not limited thereto.

The second conductivity type semiconductor <NUM> is disposed on the active layer <NUM> which will be described below. For example, the second conductivity type semiconductor <NUM> may be a p-type semiconductor having a second conductivity type. For example, when the light emitting element <NUM> emits light in a blue or green wavelength range, the second conductivity type semiconductor <NUM> may include a semiconductor material having a chemical formula of InxAlyGa<NUM>-x-yN(<NUM>≤x≤<NUM>, <NUM>≤y≤<NUM>, and <NUM>≤x+y≤<NUM>). For example, the semiconductor material may be one or more among InAlGaN, GaN, AlGaN, InGaN, AlN, and InN which are doped with a p-type impurity. The second conductivity type semiconductor <NUM> may be doped with a second conductive dopant. For example, the second conductive dopant may be Mg, Zn, Ca, Se, Ba, or the like. In an example, the second conductivity type semiconductor <NUM> may be p-GaN doped with p-type Mg. A length of the second conductivity type semiconductor <NUM> may range from <NUM> to <NUM>, but the present invention is not limited thereto.

Meanwhile, in the drawing, although each of the first conductivity type semiconductor <NUM> and the second conductivity type semiconductor <NUM> has been illustrated as being formed as one layer, the present invention is not limited thereto. In some cases, each of the first conductivity type semiconductor <NUM> and the second conductivity type semiconductor <NUM> may further include a larger number of layers, for example, a clad layer or a tensile strain barrier reducing (TSBR) layer according to a material of the active layer <NUM>.

The active layer <NUM> is disposed between the first conductivity type semiconductor <NUM> and the second conductivity type semiconductor <NUM>. The active layer <NUM> may include a material having a single or multiple quantum well structure. When the active layer <NUM> includes a material having a multiple quantum well structure, the active layer <NUM> may have a structure in which a plurality of quantum layers and a plurality of well layers are alternately stacked. The active layer <NUM> may emit light due to a combination of electron-hole pairs in response to an electrical signal applied through the first conductivity type semiconductor <NUM> and the second conductivity type semiconductor <NUM>. As an example, when the active layer <NUM> emits light in a blue wavelength range, the active layer <NUM> may include a material such as AlGaN, AlInGaN, or the like. In particular, when the active layer <NUM> has a multi-quantum well structure in which quantum layers and well layers are alternately stacked, the quantum layer may include a material such as AlGaN or AlInGaN, and the well layer may include a material such as GaN or AlInN. In an example, the active layer <NUM> includes AlGaInN as the quantum layer and AlInN as the well layer. As described above, the active layer <NUM> may emit blue light having a central wavelength range ranging from <NUM> to <NUM>.

However, the present invention is not limited thereto, and the active layer <NUM> may have a structure in which a semiconductor material having large band gap energy and a semiconductor material having small band gap energy are alternately stacked or include different Group III to V semiconductor materials according to a wavelength range of emitted light. The active layer <NUM> is not limited to emit light in the blue wavelength range, and in some cases, the active layer <NUM> may emit light in a red or green wavelength range. A length of the active layer <NUM> may range from <NUM> to <NUM>, but the present invention is not limited thereto.

Meanwhile, the light emitted from the active layer <NUM> may be emitted to an outer surface of the light emitting element <NUM> in a length direction and both side surfaces thereof. Directivity of the light emitted from the active layer <NUM> is not limited in one direction.

The conductive electrode layer <NUM> may be an ohmic contact electrode. However, the present invention is not limited thereto, and the conductive electrode layer <NUM> may be a Schottky contact electrode. The conductive electrode layer <NUM> may include a conductive metal. For example, the conductive electrode layer <NUM> may include at least one among aluminium (Al), titanium (Ti), indium (In), gold (Au), silver (Ag), indium tin oxide (ITO), indium zinc oxide (IZO), and indium tin-zinc oxide (ITZO). In addition, the conductive electrode layer <NUM> may include a semiconductor material doped with an n-type or p-type impurity. The conductive electrode layer <NUM> may include the same material or different materials, but the present invention is not limited thereto.

The insulating film <NUM> is disposed to surround the outer surfaces of the plurality of semiconductors which are described above. In an example, the insulating film <NUM> may be disposed to surround at least the outer surface of the active layer <NUM> and may extend in one direction in which the light emitting element <NUM> extends. The insulating film <NUM> may serve to protect the members. For example, the insulating film <NUM> may be formed to surround side surfaces of the members and to expose the both end portions of the light emitting element <NUM> in the length direction.

In the drawing, the insulating film <NUM> has been illustrated as being formed to extend in the length direction of the light emitting element <NUM> to cover from the first conductivity type semiconductor <NUM> to the conductive electrode layer <NUM>, but the present invention in not limited thereto. The insulating film <NUM> covers only the outer surfaces of some semiconductor layers including the active layer <NUM> or covers only a portion of the outer surface of the conductive electrode layer <NUM> so that a portion of the outer surface of the conductive electrode layer <NUM> may be exposed.

A thickness of the insulating film <NUM> may range from <NUM> to <NUM>, but the present invention is not limited thereto. Preferably, the thickness of the insulating film <NUM> may be <NUM>.

The insulating film <NUM> may include materials having insulation properties, for example, silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy), aluminium nitride (AlN), aluminium oxide (Al<NUM>O<NUM>), and the like. Thus, it is possible to prevent an electrical short circuit which may occur when the active layer <NUM> is in direct contact with an electrode through which an electrical signal is transmitted to the light emitting element <NUM>. In addition, since the insulating film <NUM> protects the outer surface of the light emitting element <NUM> including the active layer <NUM>, it is possible to prevent degradation in light emission efficiency.

In addition, in some embodiments, the outer surface of the insulating film <NUM> may be surface treated. When the display device <NUM> is manufactured, the light emitting element <NUM> may be sprayed onto an electrode in a state of being dispersed in a predetermined ink to be aligned. Here, in order to allow the light emitting element <NUM> to be maintained in the dispersed state without being agglomerated with an adjacent other light emitting element <NUM> in the ink S, the insulating film <NUM> may be hydrophobically or hydrophilically treated.

Meanwhile, the light emitting element <NUM> may have a length l ranging from <NUM> to <NUM> or from <NUM> to <NUM>, and preferably, have the length l of about <NUM>. In addition, a diameter of the light emitting element <NUM> may range from <NUM> to <NUM>, and an aspect ratio of the light emitting element <NUM> may range from <NUM> to <NUM>. However, the present invention is not limited thereto, and the plurality of light emitting elements <NUM> included in the display device <NUM> may have different diameters according to a difference in composition of the active layers <NUM>. Preferably, the diameter of the light emitting element <NUM> may be about <NUM>.

As described above, the light emitting elements <NUM> may be sprayed onto the electrodes <NUM> and <NUM> in a state of being dispersed in the ink S. In order to allow the light emitting elements <NUM> to be disposed between the electrodes <NUM> and <NUM>, it is required for the ink S to be located in the required alignment area AA. According to one embodiment, in the manufacturing process of the display device <NUM>, the coating layer <NUM> disposed in at least a partial region of the pixel PX or the sub-pixel PXn may be formed, thereby preventing the ink S in which the light emitting elements <NUM> are dispersed from spreading from the alignment area AA.

<FIG> is a schematic cross-sectional view illustrating the display device according to one embodiment.

Referring to <FIG> and <FIG>, the coating layer <NUM> may be disposed to entirely cover a target substrate SUB and the electrodes <NUM> and <NUM>. The light emitting element <NUM> may be disposed on the coating layer <NUM> between the first electrode <NUM> and the second electrode <NUM>. When the display device <NUM> is manufactured, the coating layer <NUM> disposed on the electrodes <NUM> and <NUM> may prevent the spread of the sprayed ink S to induce the light emitting element <NUM> to be disposed in the alignment area AA defined on the target substrate SUB.

<FIG> is a schematic diagram illustrating that an ink is sprayed onto an electrode according to Comparative Example. <FIG> is a cross-sectional view taken along line IIa-IIa' of <FIG>.

Referring to <FIG> and <FIG>, in order to arrange the light emitting elements <NUM> on the electrodes <NUM> and <NUM>, the ink S in which the light emitting elements <NUM> are dispersed may be sprayed onto the target substrate SUB. The alignment area AA and a non-alignment area NAA are defined on the target substrate SUB, and the ink S is sprayed onto the electrodes <NUM> and <NUM> in the alignment area AA. However, as shown in the drawings, when the coating layer <NUM> is not formed on the target substrate SUB, the ink S sprayed onto the target substrate SUB moves in at least one direction, and particularly, the ink S deviates from the alignment area AA to spread to the non-alignment area NAA. Thus, occupation of light emitting elements <NUM> located in the non-alignment area NAA among the light emitting elements <NUM> dispersed in the ink S is increased, and when an electric field is formed in the ink S in an operation, which will be described below, the number of the light emitting elements <NUM> disposed between the electrodes <NUM> and <NUM> in the alignment area AA is decreased. In this case, in the manufacturing process of the display device <NUM>, a manufacturing yield is decreased and a defective rate of the manufactured display device <NUM> is increased.

On the other hand, in the manufacturing process of the display device <NUM> according to one embodiment, the coating layer <NUM> is formed before the ink S is sprayed so that the ink S may be prevented from moving to an area other than the alignment area AA. That is, the display device <NUM> may include the coating layer <NUM> which performs a function of preventing spreading of ink S to induce the light emitting elements <NUM> to be smoothly disposed in the alignment area AA.

<FIG> is a schematic diagram illustrating that an ink is sprayed onto an electrode on which a coating layer is formed according to one embodiment. <FIG> is a cross-sectional view taken along line IIb-IIb' of <FIG>.

Referring to <FIG> and <FIG>, the display device <NUM> according to one embodiment includes the coating layer <NUM> disposed on the target substrate SUB, for example, disposed to cover the first electrode <NUM> and the second electrode <NUM>. The ink S in which the light emitting elements <NUM> are dispersed is sprayed onto the coating layer <NUM> in the alignment area AA.

The coating layer <NUM> may prevent the sprayed ink S from moving in at least one direction. The ink S sprayed onto the coating layer <NUM> may not spread in one direction and may be maintained at an initial sprayed position, and among the light emitting elements <NUM> dispersed in the ink S, occupation of light emitting elements <NUM> located in the alignment area AA may be increased. When an electric field is formed in the ink S in an operation which will be described below, most of the light emitting elements <NUM> dispersed in the ink S may be disposed between the electrodes <NUM> and <NUM> in the alignment area AA.

The spreading prevention function of the coating layer <NUM> may be induced by controlling a contact angle θd using a difference in surface energy between the coating layer <NUM> and a solvent of the ink S. According to one embodiment, the ink S in which the light emitting elements <NUM> are dispersed may include a solvent having a first polarity, and at least a partial region of the coating layer <NUM> may include a material having a second polarity opposite to the first polarity. The second polarity is hydrophobic.

As shown in <FIG> and <FIG>, the ink S sprayed onto the target substrate SUB may form a predetermined contact angle θd on an interface with the target substrate SUB or the coating layer <NUM>. A liquid sprayed onto a target object may have a shape which minimizes surface energy of a surface of the liquid. The ink S sprayed onto the target substrate SUB or the coating layer <NUM> may have a spherical or semi-elliptical shape which minimizes surface energy on a surface of the ink S.

Here, as in portion A of <FIG> and <FIG>, surface energy may be formed on interfaces between the ink S and the target substrate SUB or the coating layer <NUM>, between air and the target substrate SUB or the coating layer <NUM>, and between the air and the ink S in one directions.

As in portion A of <FIG>, first surface energy γSL is formed on the interface between the ink S and the target substrate SUB, a second surface energy γSV is formed on the interface between the target substrate SUB and the air, and third surface energy γLV is formed on the interface between the ink S and air. When a contact angle θd is formed between a surface of the ink S and the target substrate SUB, a relationship therebetween satisfies the following equation <NUM>. <MAT> (Here, γSL is the first surface energy, γSV is the second surface energy, γLV is the third surface energy, and θd is the contact angle between the surface of the ink S and the target substrate SUB).

To describe with reference to Equation <NUM> and <FIG>, when an γSL value which is the first surface energy is smaller than an γSV value which is the second surface energy, the ink S may exhibit a behavior so as to minimize surface energy of the interface. That is, a force is applied to the ink S at a point at which the ink S is in contact with the target substrate SUB in one direction of a transverse direction in which the second surface energy γSV having a large value is applied, and the surface of the ink S may move in the one direction. Thus, the contact angle θd between the ink S and the target substrate SUB is decreased, and the ink S spreads in the one direction on the target substrate SUB.

On the other hand, to describe with reference to Equation <NUM> and <FIG>, when the ink S is sprayed onto the coating layer <NUM>, and when the γSL value that is the first surface energy is greater than the γSV value that is the second surface energy, in order to minimize surface energy of the interface, a force may be applied to the ink S in the one direction of the transverse direction to which the first surface energy γSL having a large value is applied. Thus, the contact angle θd between the ink S and the coating layer <NUM> may be increased, and the ink S may be maintained at the first sprayed position without moving on the coating layer <NUM>.

The coating layer <NUM> may control a difference between the first surface energy γSL and the second surface energy γSV from the ink S. For example, the ink S may be sprayed onto the coating layer <NUM>, and thus the first surface energy γSL may have a value greater than a value of the second surface energy γSV on the interface between the coating layer <NUM> and the ink S. In this case, the force acts in a direction to which the first surface energy γSL is directed so that the coating layer <NUM> may induce the surface energy of the ink S to have a small value and may prevent the ink S from spreading.

The coating layer <NUM> according to one embodiment includes a material having a polarity opposite to a polarity of the solvent of ink S, and thus the first surface energy γSL and the contact angle θd between the coating layer <NUM> and the ink S may each have a large value. The coating layer <NUM> may prevent the ink S sprayed on the alignment area AA from spreading to the non-alignment area NAA.

The solvent of the ink S is hydrophilic, and at least a portion of the coating layer <NUM> includes a hydrophobic material. Thus, the contact angle θd between the coating layer <NUM> and the ink S may have a value of <NUM>° or more. As the coating layer <NUM> includes a hydrophobic material, the hydrophobic material may be a polymer including fluorine (F). As an example, the coating layer <NUM> may include <NUM>,<NUM>,<NUM>,<NUM>-perfluorodecyltrichlorosilane. In addition, some regions of the coating layer <NUM> may have the same polarity as the ink S, and the remaining regions of the coating layer <NUM> may have a polarity opposite to a polarity of the ink S.

For example, the coating layer <NUM> may include a first region and a second region which have different polarities, and the ink S may be sprayed between the first and second regions. In this case, when the surface energy of the ink S is increased as the interface between the ink S and the coating layer <NUM> is changed from the first region to the second region, the coating layer <NUM> may prevent the ink S from moving to the second region. That is, it is possible to prevent the ink S from spreading from the first region to the second region on the coating layer <NUM>. A description thereof will be made below with reference to other drawings.

Meanwhile, as described above, the display device <NUM> may further include a contact electrode <NUM> in contact with the light emitting element <NUM> and the electrodes <NUM> and <NUM>. The contact electrode <NUM> may be in contact with at least one end portion of the light emitting element <NUM> and may be in contact with regions of the electrodes <NUM> and <NUM> in which the coating layer <NUM> is partially removed to be exposed.

<FIG> and <FIG> are schematic cross-sectional views illustrating a display device according to another embodiment.

First, referring to <FIG>, the coating layer <NUM> includes the opening 80P which exposes at least a portion of each of the electrodes <NUM> and <NUM> and may further include the contact electrode <NUM> in contact with the electrodes <NUM> and <NUM> which are exposed through the opening 80P. The coating layer <NUM> may be disposed to cover the electrodes <NUM> and <NUM>, and the opening 80P overlaps the electrodes <NUM> and <NUM> to expose a partial region of each of the electrodes <NUM> and <NUM>. An area in which the opening 80P is disposed is an area in which the coating layer <NUM> partially exposes upper surfaces of the electrodes <NUM> and <NUM> in <FIG>. As shown in the drawings, the opening 80P may partially expose the upper surfaces of the electrodes <NUM> and <NUM>, but the present invention is not limited thereto. As described below with reference to <FIG>, the opening 80P may entirely expose flat upper surfaces of the electrodes <NUM> and <NUM> and may partially expose inclined side surfaces of the electrodes <NUM> and <NUM>.

The contact electrode <NUM> is disposed on the electrodes <NUM> and <NUM>. The contact electrode <NUM> may be in contact with the light emitting element <NUM> and the regions of the electrodes <NUM> and <NUM> which are exposed through the opening 80P. The contact electrode <NUM> includes a first contact electrode 26a disposed on the first electrode <NUM> and a second contact electrode 26b disposed on the second electrode <NUM>. The first contact electrode 26a may be in contact with the exposed region of the first electrode <NUM> and one end portion of the light emitting element <NUM>, and the second contact electrode 26b may be contact with the exposed region of the second electrode <NUM> and the other end portion of the light emitting element <NUM>.

In the manufacturing process of the display device <NUM>, the coating layer <NUM> may be formed to entirely cover the target substrate SUB and the electrodes <NUM> and <NUM> to dispose the light emitting element <NUM> in the alignment area AA, and the opening 80P may be formed to expose a portion of each of the electrodes <NUM> and <NUM>. Even when the coating layer <NUM> entirely covers the electrodes <NUM> and <NUM>, since the display device <NUM> further includes the contact electrode <NUM> in contact with the light emitting element <NUM> and the electrodes <NUM> and <NUM> exposed through the opening 80P, electrical signals transmitted from the electrodes <NUM> and <NUM> may be transmitted to the light emitting element <NUM> through the contact electrode <NUM>.

Referring to <FIG>, the opening 80P of the coating layer <NUM> may expose at least a portion of a side surface, including the upper surface, of each of the electrodes <NUM> and <NUM>. Areas of the electrodes <NUM> and <NUM> exposed by the opening 80P are increased, and the contact electrode <NUM> may be in contact with the electrodes <NUM> and <NUM> in a larger region. Thus, contact resistance between the contact electrode <NUM> and the electrodes <NUM> and <NUM> may be reduced. However, the structure of the display device <NUM> is not limited thereto, and the display device <NUM> may have a structure different from the above structure or a larger number of members may be disposed on the target substrate SUB. A description thereof will be made with reference to other drawings.

Hereinafter, the display device <NUM> will be described in detail with reference to other drawings.

<FIG> is a partial cross-sectional view taken along line I-I' of <FIG>.

<FIG> illustrates the cross-sectional view of the first sub-pixel PX1 and may be equally applied to other pixels PX or other sub-pixels PXn. <FIG> illustrates a cross section crossing one end portion and the other end portion of an arbitrary light emitting element <NUM>.

Meanwhile, although not shown in <FIG>, the display device <NUM> may further include a circuit element layer located below the electrodes <NUM> and <NUM>. The circuit element layer may include a plurality of semiconductor layers and a plurality of conductive patterns and may include at least one transistor and a power line. However, a detailed description thereof will be omitted below.

To describe the display device <NUM> in detail with reference to <FIG>, the display device <NUM> may include a via layer <NUM>, the electrodes <NUM> and <NUM> disposed on the via layer <NUM>, and the light emitting element <NUM>. A circuit element layer (not shown) may be further disposed below the via layer <NUM>. The via layer <NUM> may include an organic insulating material and perform a surface planarization function.

A plurality of banks <NUM>, <NUM>, and <NUM> are disposed on the via layer <NUM>. The plurality of banks <NUM>, <NUM>, and <NUM> may be disposed to be separated from each other in each sub-pixel PXn. The plurality of banks <NUM>, <NUM>, and <NUM> may include the first bank <NUM> and the second bank <NUM> which are disposed adjacent to a central portion of the sub-pixel PXn, and the third bank <NUM> disposed at a boundary between the sub-pixels PXn.

When an ink S is sprayed using an inkjet printing device during the manufacturing of the display device <NUM>, the third bank <NUM> may perform a function of blocking the ink S from crossing the boundary of the sub-pixel PXn. In addition, when the display device <NUM> further includes other members, the other members may be disposed on the third bank <NUM>, and the third bank <NUM> may perform a function of supporting the other members. However, the present invention is not limited thereto.

The first bank <NUM> and the second bank <NUM> are disposed to be separated from and opposite to each other. The first electrode <NUM> is disposed on the first bank <NUM>, and the second electrode <NUM> is disposed on the second bank <NUM>. Referring to <FIG> and <FIG>, it can be understood that the first electrode branch portion 21B is disposed on the first bank <NUM>, and the second bank <NUM> is disposed on the second bank <NUM>.

As described above, the first bank <NUM>, the second bank <NUM>, and the third bank <NUM> may be formed substantially in the same process. Thus, the banks <NUM>, <NUM>, and <NUM> may constitute a single grid pattern. Each of the plurality of banks <NUM>, <NUM>, and <NUM> may include polyimide (PI).

Each of the plurality of banks <NUM>, <NUM>, and <NUM> may have a structure in which at least a portion protrudes from the via layer <NUM>. The banks <NUM>, <NUM>, and <NUM> may protrude upward from a flat surface on which the light emitting element <NUM> is disposed, and at least a part of each of the protruding portions may have a slope. A shape of each of the banks <NUM>, <NUM>, and <NUM> having the protruding structures is not particularly limited. As shown in the drawing, the first bank <NUM> and the second bank <NUM> protrude to the same height, and the third bank <NUM> may have a shape protruding to a higher position.

Reflective layers 21a and 22a may be disposed on the first bank <NUM> and the second bank <NUM>, and electrode layers 21b and 22b may be disposed on the reflective layers 21a and 22a. The reflective layers 21a and 22a and the electrode layers 21b and 22b may constitute the electrodes <NUM> and <NUM>.

The reflective layers 21a and 22a include a first reflective layer 21a and a second reflective layer 22a. The first reflective layer 21a may cover the first bank <NUM>, and the second reflective layer 22a may cover the second bank <NUM>. Portions of the reflective layers 21a and 22a are electrically connected to the circuit element layer through a contact hole passing through the via layer <NUM>.

Each of the reflective layers 21a and 22a may include a material having high reflectance to reflect light emitted from the light emitting element <NUM>. For example, each of the reflective layers 21a and 22a may include a material such as Ag, Cu, ITO, IZO, or ITZO, but the present invention is not limited thereto.

The electrode layers 21b and 22b include a first electrode layer 21b and a second electrode layer 22b. The electrode layers 21b and 22b may have patterns substantially equal to patterns of the reflective layers 21a and 22a. The first reflective layer 21a and the first electrode layer 21b are disposed to be separated from the second reflective layer 22a and the second electrode layer 22b.

Each of the electrode layers 21b and 22b includes a transparent conductive material, and thus light emitted from the light emitting element <NUM> may be incident on the reflective layers 21a and 22a. For example, each of the electrode layers 21b and 22b may include a material such as ITO, IZO, or ITZO, but the present invention is not limited thereto.

In some embodiments, the reflective layers 21a and 22a and the electrode layers 21b and 22b may form a structure in which one or more transparent conductive layers such as ITO, IZO, or ITZO, and one or more metal layers such as Ag or Cu are stacked. For example, the reflective layers 21a and 22a and the electrode layers 21b and 22b may form a stacked structure of ITO/Ag/ITO/IZO.

Meanwhile, in some embodiments, the first electrode <NUM> and the second electrode <NUM> may be formed as a single layer. That is, the reflective layers 21a and 22a and the electrode layers 21b and 22b may be formed as a single layer to transmit an electrical signal to the light emitting element <NUM> and, simultaneously, reflect light. For example, each of the first electrode <NUM> and the second electrode <NUM> may include a conductive material having high reflectance and may be an alloy containing Al, nickel (Ni), and lanthanum (La). However, the present invention is not limited thereto.

The first insulating layer <NUM> is disposed to partially cover the first electrode <NUM> and the second electrode <NUM>. The first insulating layer <NUM> may be disposed to cover most of upper surfaces of the first electrode <NUM> and the second electrode <NUM> and may expose portions of the first electrode <NUM> and the second electrode <NUM>. The first insulating layer <NUM> may be disposed to partially cover an area in which the first electrode <NUM> is separated from the second electrode <NUM> and an area opposite to the area in which the first electrode <NUM> is separated from the second electrode <NUM>.

The first insulating layer <NUM> is disposed to expose relatively flat upper surfaces of the first electrode <NUM> and the second electrode <NUM> and disposed to allow the electrodes <NUM> and <NUM> to overlap inclined surfaces of the first bank <NUM> and the second bank <NUM>. The first insulating layer <NUM> forms a flat upper surface to allow the light emitting element <NUM> to be disposed, and the flat upper surface extends toward the first electrode <NUM> and the second electrode <NUM> in one direction. The extension portion of the first insulating layer <NUM> is terminated at inclined surfaces of the first electrode <NUM> and the second electrode <NUM>. Thus, the contact electrodes <NUM> may be in contact with the exposed first electrode <NUM> and the exposed second electrode <NUM> and may be in smooth contact with the light emitting element <NUM> on the flat upper surface of the first insulating layer <NUM>.

The first insulating layer <NUM> may protect the first electrode <NUM> and the second electrode <NUM> and, simultaneously, insulate the first electrode <NUM> from the second electrode <NUM>. In addition, the first insulating layer <NUM> may prevent the light emitting element <NUM> disposed thereon from being damaged by direct contact with other members.

The coating layer <NUM> is disposed on the first insulating layer <NUM>. The coating layer <NUM> may have substantially the same shape as the first insulating layer <NUM> in a cross section. The above shape may be formed such that a material constituting the first insulating layer <NUM> and a material constituting the coating layer <NUM> are sequentially disposed on the electrodes <NUM> and <NUM> in the manufacturing process of the display device <NUM> and then etched in the same process. The opening 80P of the coating layer <NUM> may be formed in a region in which the first insulating layer <NUM> and the coating layer <NUM> are etched, thereby exposing some regions of the electrodes <NUM> and <NUM>. Some regions of the electrodes <NUM> and <NUM> exposed through the opening 80P may be in contact with the contact electrode <NUM> which will be described below. However, the present invention is not limited thereto, and the coating layer <NUM> may be disposed in only a partial region on the first insulating layer <NUM> so that the coating layer <NUM> and the first insulating layer <NUM> may have different shapes. A description of the coating layer <NUM> is the same as the above description, and thus a detailed description thereof will be omitted herein. In addition, various examples of the coating layer <NUM> will be described below with reference to other drawings.

The light emitting element <NUM> may be disposed on the coating layer <NUM> or the first insulating layer <NUM>. In the drawing, the light emitting element <NUM> is shown as being disposed on the coating layer <NUM> which is disposed on the first insulating layer <NUM>. At least one light emitting element <NUM> may be disposed on the coating layer <NUM> between the first electrode <NUM> and the second electrode <NUM>. The light emitting element <NUM> may include a plurality of layers disposed in a direction horizontal to the via layer <NUM>.

The light emitting element <NUM> of the display device <NUM> according to one embodiment may include the conductive semiconductors and the active layer, which are described above, and the conductive semiconductors and the active layer may be sequentially disposed on the via layer <NUM> in the transverse direction. As shown in the drawing, in the light emitting element <NUM>, the first conductivity type semiconductor <NUM>, the active layer <NUM>, the second conductivity type semiconductor <NUM>, and the conductive electrode layer <NUM> may be sequentially disposed on the via layer <NUM> in the horizontal direction. However, the present invention is not limited thereto. The order of the plurality of layers disposed in the light emitting element <NUM> may be the opposite. In some cases, when the light emitting element <NUM> has another structure, the plurality of layers may be disposed in a direction perpendicular to the via layer <NUM>.

The second insulating layer <NUM> may be partially disposed on the light emitting element <NUM>. The second insulating layer <NUM> may protect the light emitting element <NUM> and, simultaneously, perform a function of fixing the light emitting element <NUM> during a process of manufacturing the display device <NUM>. The second insulating layer <NUM> may be disposed to surround an outer surface of the light emitting element <NUM>. That is, a portion of a material of the second insulating layer <NUM> may be disposed between a bottom surface of the light emitting element <NUM> and the first insulating layer <NUM>. The second insulating layer <NUM> may extend between the first electrode branch portion 21B and the second electrode branch portion 22B in the second direction Y-axis to have an island shape or a linear shape when viewed in a plan view.

The contact electrodes <NUM> are disposed on the electrodes <NUM> and <NUM> and the second insulating layer <NUM>. The first contact electrode 26a and the second contact electrode 26b are disposed to be spaced apart from each other on the second insulating layer <NUM>. Thus, the second insulating layer <NUM> may insulate the first contact electrode 26a from the second contact electrode 26b.

The first contact electrode 26a may be in contact with at least the first electrode <NUM>, which is exposed due to patterning of the first insulating layer <NUM> and the coating layer <NUM> and may be in contact with one end portion of the light emitting element <NUM>. The second contact electrode 26b may be in contact with at least the second electrode <NUM>, which is exposed due to the patterning of the first insulating layer <NUM> and the coating layer <NUM> and may be in contact with the other end portion of the light emitting element <NUM>. The first and second contact electrodes 26a and 26b may be in contact with side surfaces of the two end portions of the light emitting element <NUM>, for example, the first conductivity type semiconductor <NUM>, the second conductivity type semiconductor <NUM>, or the conductive electrode layer <NUM>. As described above, the first insulating layer <NUM> forms the flat upper surface so that the contact electrodes <NUM> may be in smooth contact with the side surfaces of the light emitting element <NUM>.

The contact electrode <NUM> may include a conductive material. For example, the contact electrode <NUM> may include ITO, IZO, ITZO, Al, or the like. However, the present invention is not limited thereto.

The passivation layer <NUM> is disposed above the second insulating layer <NUM> and the contact electrode <NUM>. The passivation layer <NUM> may serve to protect members disposed on the via layer <NUM> from an external environment.

Each of the first insulating layer <NUM>, the second insulating layer <NUM>, and the passivation layer <NUM>, which are described above, may include an inorganic insulating material or an organic insulating material. In an example, each of the first insulating layer <NUM>, the second insulating layer <NUM>, and the passivation layer <NUM> may include a material such as SiOx, SiNx, SiOxNy, Al<NUM>O<NUM>, aluminium nitride (AlN), or the like. The second insulating layer <NUM> may be made of an organic insulating material including a photoresist or the like. However, the present invention is not limited thereto.

Hereinafter, a method of manufacturing the display device <NUM> according to one embodiment will be described.

<FIG> is a flowchart illustrating a method of manufacturing a display device according to one embodiment.

Referring to <FIG>, the method of manufacturing the display device <NUM> includes preparing a target substrate SUB and the first electrode <NUM> and the second electrode <NUM> which are disposed on the target substrate SUB (S100), forming the coating layer <NUM> disposed on at least a partial region of the target substrate SUB and configured to cover at least a portion of each of the first electrode <NUM> and the second electrode <NUM> (S200), and spraying the ink S including the light emitting elements <NUM> onto the coating layer <NUM> which covers the first electrode <NUM> and the second electrode <NUM> and landing the light emitting elements <NUM> between the first electrode <NUM> and the second electrode <NUM> (S300).

The method of manufacturing the display device <NUM> according to one embodiment includes preparing the first electrode <NUM> and the second electrode <NUM> which are disposed on the target substrate SUB, forming the coating layer <NUM> disposed on at least a partial region of the target substrate SUB, and then landing the light emitting elements <NUM> between the first electrode <NUM> and the second electrode <NUM>. The coating layer <NUM> is disposed to partially overlap the electrodes <NUM> and <NUM> on the target substrate SUB, but the present invention is not limited thereto. In some cases, the coating layer <NUM> may be disposed only in a region other than the first electrode <NUM> and the second electrode <NUM>. Hereinafter, an example in which the coating layer <NUM> entirely covers, including the first electrode <NUM> and the second electrode <NUM>, the target substrate SUB will be described.

<FIG> are cross-sectional views illustrating processes of the method of manufacturing a display device according to one embodiment.

First, as shown in <FIG>, the target substrate SUB on which the first electrode <NUM> and the second electrode <NUM> are formed is prepared (S100). For convenience of description, in the following drawings, only the electrodes <NUM> and <NUM>, the coating layer <NUM>, and the light emitting elements <NUM>, which are disposed on the target substrate SUB, are shown. However, the display device <NUM> is not limited thereto, and as described above, the display device <NUM> may include more members such as the bank <NUM>, the contact electrode <NUM>, and the like.

Next, as shown in <FIG>, the coating layer <NUM> is formed to be disposed on the target substrate SUB and the electrodes <NUM> and <NUM> (S200). A method of forming the coating layer <NUM> is not particularly limited. In one embodiment, the coating layer <NUM> may include a self-assembly monolayer and may be formed on the electrodes <NUM> and <NUM>. However, the present invention is not limited thereto.

Next, as shown in <FIG>, the ink S including the light emitting element <NUM> is sprayed onto the first electrode <NUM> and the second electrode <NUM>. The ink S may be disposed on the coating layer <NUM> which is disposed to cover the first electrode <NUM> and the second electrode <NUM>.

The ink S may include a solvent and a plurality of light emitting elements <NUM> included in the solvent. In an example, the ink S may be provided in a solution or colloidal state. For example, the solvent may be acetone, water, alcohol, toluene, propylene glycol (PG), or propylene glycol methyl acetate (PGMA), but the present invention is not limited thereto. For example, ink S may include hydrophilic PG as a solvent, and the coating layer <NUM> may include a hydrophobic fluorine-based polymer. That is, the ink S and the coating layer <NUM> may include materials having opposite polarities. The coating layer comprising a material having a hydrophobic polarity.

Thus, the first surface energy γSL (not shown) formed on the interface between the coating layer <NUM> and the ink S has a large value, and the contact angle θd between the ink S and the coating layer <NUM> has a large value. The ink S sprayed on the coating layer <NUM> may be maintain at a first sprayed position without spreading in one direction. In particular, the ink S is sprayed in the alignment area AA defined on the first electrode <NUM> and the second electrode <NUM>, and thus a large number of light emitting elements <NUM> may be located in the alignment area AA.

Next, as shown in <FIG> and <FIG>, the light emitting element <NUM> is landed between the first electrode <NUM> and the second electrode <NUM> (S300). The landing of the light emitting element <NUM> (S300) may include applying an electrical signal to the first electrode <NUM> and the second electrode <NUM> and forming an electric field in the ink S, applying a dielectrophoretic force to the light emitting element <NUM> due to the electric field and landing the light emitting element <NUM> on the electrodes <NUM> and <NUM>, and removing the solvent of the ink S.

The light emitting element <NUM> may be disposed on the electrodes <NUM> and <NUM> using dielectrophoresis (DEP). The solution in which the light emitting elements <NUM> are dispersed is sprayed onto the electrodes <NUM> and <NUM>, and alternating-current (AC) power is applied to the electrodes <NUM> and <NUM>. When the AC power is applied to the first electrode <NUM> and the second electrode <NUM>, an electric field is generated between the first electrode <NUM> and the second electrode <NUM>, and the light emitting element <NUM> receiving a dielectrophoretic force due to the electric field may be disposed on the electrodes <NUM> and <NUM>.

As shown in the drawing, when the AC power is applied to the electrodes <NUM> and <NUM>, an electric field E may be formed in the ink S sprayed onto the electrodes <NUM> and <NUM>. The electric field E may apply a dielectrophoretic force to the light emitting element <NUM>, and the light emitting element <NUM> receiving the dielectrophoretic force may be landed on the first electrode <NUM> and the second electrode <NUM>.

Next, when the light emitting element <NUM> is landed on the electrodes <NUM> and <NUM>, the solvent of the ink S is removed. The removing of the solvent may employ a conventional method. For example, the solvent may be removed through a method such as a heat treatment method, an infrared irradiation method, or the like. The display device <NUM> including the coating layer <NUM> may be manufactured through the above processes. However, the method of manufacturing the display device <NUM> is not limited thereto. As described above, the display device <NUM> may include a larger number of members, and thus more processes may be performed. A detailed description thereof will be omitted herein.

Hereinafter, another embodiment of the display device <NUM> will be described with reference to other drawings.

<FIG> are plan views illustrating the display device according to another embodiment.

Referring to <FIG>, a display device 1_1 according to one embodiment may be formed such that a coating layer 80_1 substantially overlaps the alignment area AA. In the display device 1_1 of <FIG>, the coating layer 80_1 may be formed in a relatively narrow area when compared with the display device <NUM> of <FIG>. Hereinafter, a duplicate description will be omitted and a description will be made to focus on a difference.

The coating layer 80_1 of the display device 1_1 may be disposed to overlap only an alignment area AA in which light emitting elements <NUM> are aligned. In the drawing, in order to distinguish the alignment area AA from the coating layer 80_1, boundaries of the alignment area AA and the coating layer 80_1 have been illustrated as being spaced apart from each other, but the coating layer 80_1 may overlap the alignment area AA. A first electrode branch portion 21B and a second electrode branch portion 22B may be disposed in the alignment area AA, and the coating layer 80_1 may be disposed to partially cover the first electrode branch portion 21B and the second electrode branch portion 22B.

When an ink S including the light emitting elements <NUM> is sprayed in only the alignment area AA in a manufacturing process of the display device 1_1, the coating layer 80_1 may be disposed on electrodes <NUM> and <NUM> overlapping the alignment area AA to prevent the ink S from spreading. The ink S disposed on the coating layer 80_1, which is disposed in the alignment area AA, may form first surface energy γSL and a contact angle θd, each having a large value, on an interface between the ink S and the coating layer 80_1 and may be prevented from spreading to a non-alignment area NAA. Thus, a large number of light emitting elements <NUM> in the ink S may be located in the alignment area AA, and the light emitting elements <NUM> may be disposed between the electrodes <NUM> and <NUM> in the alignment area AA, that is, between the first electrode branch portion 21B and the second electrode branch portion 22B.

Meanwhile, the light emitting element <NUM> is disposed between the electrodes <NUM> and <NUM> opposite to each other in the alignment area AA. Each of the first electrode <NUM> and the second electrode <NUM> includes two side surfaces, and the light emitting element <NUM> is disposed between facing side surfaces of the first electrode <NUM> and the second electrode <NUM>. That is, the ink S including the light emitting element <NUM> may be sprayed between the facing side surfaces of the electrodes <NUM> and <NUM>. The coating layer <NUM> according to one embodiment may be disposed to overlap the electrodes <NUM> and <NUM> and disposed to overlap at least facing one side surfaces of the electrodes <NUM> and <NUM> and not to overlap the other side surfaces thereof.

Referring to <FIG>, a coating layer 80_2 of a display device 1_2 is disposed in an alignment area AA and disposed to partially overlap a first electrode branch portion 21B and a second electrode branch portion 22B. Two side surfaces of the second electrode branch portion 22B are opposite to different first electrode branch portions 21B, and thus the coating layer 80_2 overlaps the two side surfaces of the second electrode branch portion 22B. On the other hand, one side surface of the first electrode branch portion 21B, that is, one side surface located at an outer side on a central portion of the sub-pixel PXn in the drawing, is not opposite to the second electrode branch portion 22B.

According to one embodiment, each of the electrodes <NUM> and <NUM> may include one side surface and the other side surface, and the coating layer 80_2 may be disposed to overlap the one side surfaces of the electrodes <NUM> and <NUM> and disposed to not overlap the other side surfaces thereof. As shown in the drawing, the coating layer 80_2 is disposed to overlap one side surface of the first electrode branch portion 21B facing the second electrode branch portion 22B and disposed to not overlap of the other side surface of the first electrode branch portion 21B. An ink S may be sprayed on the coating layer 80_2 between the first electrode branch portion 21B and the second electrode branch portion 22B which faces each other, and the coating layer 80_2 may prevent the ink S from spreading to the other side surface of the first electrode branch portion 21B. Thus, most of the light emitting elements <NUM> in the ink S may be located between the first electrode branch portion 21B and the second electrode branch portion 22B.

Meanwhile, the coating layer <NUM> may be disposed in a region in which side surfaces of the electrodes <NUM> and <NUM> are opposite to each other and which is an area in which the light emitting elements <NUM> are disposed, and the coating layer <NUM> may form a plurality of coating patterns 80a to form a plurality of coating patterns 80a and may be disposed in opposite regions of the electrodes <NUM> and <NUM>.

Referring to <FIG> and <FIG>, coating layers 80_3 and 80_4 of display devices 1_3 and 1_4 according to one embodiment include at least one coating pattern 80a_3 and at least one coating pattern 80a_4, and each of the coating patterns 80a_3 and 80a_4 may be disposed between the first electrode <NUM> and the second electrode <NUM>. In the display device 1_3 of <FIG>, one coating layer 80_3 may be disposed between a first electrode branch portion 21B and a second electrode branch portion 22B. In the display device 1_4 of <FIG>, two coating layers 80_4 may be disposed to be spaced apart from each other between the first electrode branch portion 21B and the second electrode branch portion 22B.

Each of the coating patterns 80a_3 and 80a_4 may extend in the second direction Y-axis and may be disposed to be spaced apart in the first direction X-axis. The coating patterns 80a_3 and 80a_4 may partially overlap each of facing side surfaces of the first electrode branch portion 21B and the second electrode branch portion 22B and may also partially overlap a gap region in which the first electrode branch portion 21B is spaced apart from the second electrode branch portion 22B. The ink S including the light emitting elements <NUM> may be sprayed on the coating pattern 80a_3 of <FIG> or the coating pattern 80a_4 of <FIG> between the first electrode branch portion 21B and the second electrode branch portion 22B. The coating patterns 80a_3 and 80a_4 may prevent the ink S from spreading in a separated region between the first electrode branch portion 21B and the second electrode branch portion 22B.

<FIG> is a schematic cross-sectional view illustrating that an ink is sprayed onto the display device of <FIG>.

Specifically, referring to <FIG>, the coating pattern 80a_4 is disposed to cover side surfaces of the first electrode <NUM> and the second electrode <NUM> opposite to each other and a region between the first electrode <NUM> and the second electrode <NUM>. The ink S is sprayed onto the coating patterns 80a_4 of <FIG> between the first electrode <NUM> and the second electrode <NUM>. A surface of the ink S sprayed onto the coating pattern 80a_4 may form a large contact angle θd on an interface with the coating pattern 80a_4 and may be prevented from spreading to an outer side of the coating pattern 80a_4. Thus, most of the light emitting elements <NUM> may be disposed between the first electrode <NUM> and the second electrode <NUM>.

Meanwhile, when the ink S is sprayed in the alignment area AA, the coating layer <NUM> may not necessarily be disposed in the alignment area AA but may be disposed in only the non-alignment area NAA. The coating layer <NUM> disposed in the non-alignment area NAA may prevent the ink S sprayed in the alignment area AA from spreading to the non-alignment area NAA.

<FIG> is a plan view illustrating a display device according to yet another embodiment. <FIG> is a schematic cross-sectional view illustrating that an ink is sprayed onto the display device of <FIG>.

Referring to <FIG> and <FIG>, a coating layer 80_5 of a display device 1_5 according to one embodiment may be disposed to overlap only a non-overlapping area NAA without overlapping an alignment area AA. When an ink S overlaps the alignment area AA, the ink S may be sprayed onto the electrodes <NUM> and <NUM> on which the coating layer 80_5 is not disposed and may spread to a boundary of a region in which the coating layer 80_5 is disposed. However, the coating layer 80_5 may prevent the ink S from spreading onto the coating layer 80_5 at the boundary, that is, the boundary between the alignment area AA and the non-alignment area NAA.

Specifically, as shown in <FIG>, the coating layer 80_5 is disposed in only the non-alignment area NAA, and the ink S is disposed on the first electrode <NUM> and the second electrode <NUM> in the alignment area AA. The ink S disposed in the alignment area AA may spread in at least one direction without forming an interface with the coating layer 80_5.

When the ink S spreads to the boundary between the alignment area AA and the non-alignment area NAA, the ink S is in partial contact with the coating layer 80_5. Here, when the ink S contains a solvent of a first polarity and the coating layer 80_5 contains a material of a second polarity opposite to the first polarity, surface energy has a large value in an interface at which the ink S is in contact with the coating layer 80_5. In order to minimize surface energy on a surface of the ink S, the ink S may be moved to decrease an area in contact with the coating layer 80_5 in which the surface energy having a large value is formed. That is, when the ink S is in contact with the coating layer 80_5, a force is applied in a direction opposite to the one direction in which the ink S spreads in the alignment area AA. That is, the ink S does not move onto the coating layer 80_5 and is prevented from spreading at the boundary between the alignment area AA and the non-alignment area NAA, which is the boundary with the coating layer 80_5. Thus, the coating layer 80_5 may prevent the light emitting elements <NUM> from being moved to the non-alignment area NAA.

That is, the coating layer <NUM> contains a material having a polarity opposite to a polarity of the ink S to prevent the ink S from spreading to the non-alignment area NAA. This means that the ink S sprayed onto the alignment area AA may spread in the alignment area AA. The coating layer <NUM> according to one embodiment may include a first coating layer <NUM> and a second coating layer <NUM> which have different polarities. One of the first coating layer <NUM> and the second coating layer <NUM> may have the same polarity as the ink S, and the other one thereof may have a polarity opposite to the polarity of the ink S.

<FIG> is a plan view illustrating a display device according to yet another embodiment.

Referring to <FIG>, a coating layer 80_6 of a display device 1_6 according to one embodiment may include a first coating layer 81_6 and a second coating layer 82_6. The first coating layer 81_6 may include a material having a first polarity, and the second coating layer 82_6 may include a material having a second polarity different from the first polarity. For example, the first coating layer 81_6 may include a hydrophobic material, and the second coating layer 82_6 may include a hydrophilic material. However, the present invention is not limited thereto, and the first polarity and the second polarity may be reversed.

In an example, in a manufacturing process of the display device 1_6, an ink S including the light emitting elements <NUM> may include a second polarity, for example, a hydrophilic solvent, and the display device 1_6 may include a second coating layer 82_6 overlapping an alignment area AA and a first coating layer 81_6 overlapping a non-alignment area NAA. The first coating layer 81_6 is disposed to substantially surround the second coating layer 82_6, and the second coating layer 82_6 is disposed to partially overlap a first electrode <NUM> and a second electrode <NUM> in the alignment area AA. Although not shown in the drawing, the second coating layer 82_6 may include an opening 80P exposing at least a portion of the electrodes <NUM> and <NUM>, and a contact electrode <NUM> may be in contact with the electrodes <NUM> and <NUM> through the opening 80P. A description thereof is the same as described above.

The ink S including the light emitting elements <NUM> is sprayed onto the second coating layer 82_6 in the alignment area AA. The second coating layer 82_6 and the ink S may include materials or solvents having the same second polarity. The ink S may form a low surface energy on an interface with the second coating layer 82_6 to spread in at least one direction in the alignment area AA.

A boundary between the first coating layer 81_6 and the second coating layer 82_6 is formed at a boundary between the alignment area AA and the non-alignment area NAA. The ink S may spread in one direction in the alignment area AA and may be in partial contact with the first coating layer 81_6 at the boundary between the first coating layer 81_6 and the second coating layer 82_6.

Referring to <FIG>, the ink S may move on the second coating layer 82_6 and may be in contact with the first coating layer 81_6 at the boundary with the first coating layer 81_6. Since the ink S contains a solvent having a polarity opposite to the polarity of the first coating layer 81_6, a surface energy having a large value is formed on a surface in contact with the first coating layer 81_6. In order to minimize the surface energy on the surface of the ink S, a force is transmitted in a direction of minimizing an area of the surface in which surface energy having a large value is formed and which is in contact with the first coating layer 81_6. That is, the surface of the ink S is balanced due to forces in opposite directions at the boundary between the first coating layer 81_6 and the second coating layer 82_6 so that the ink S is prevented from spreading onto the first coating layer 81_6. Thus, the light emitting elements <NUM> are located in the alignment area AA on the second coating layer 82_6.

<FIG> are plan views illustrating a display device according to yet another embodiment.

The second coating layer <NUM> may include a material having the same polarity as the solvent of the ink S. In this case, the surface energy of the ink S on the interface formed with the second coating layer <NUM> may be smaller than the surface energy thereof on the interface formed with the target substrate SUB or the electrodes <NUM> and <NUM> on which the coating layer <NUM> is not formed. In order to have a lower surface energy value, the ink S may move in a direction of increasing a surface in contact with the second coating layer <NUM>. That is, an attractive force may be transferred to the ink S by the second coating layer <NUM>. According to one example, the second coating layer <NUM> may be disposed in the alignment area AA and may include at least one coating pattern 82a, and the coating pattern 82a may at least be disposed between regions in which the electrodes <NUM> and <NUM> are opposite to each other.

Referring to <FIG> first, a coating layer 80_7 of a display device 1_7 may include a first coating layer 81_7 disposed in a non-alignment area NAA and a second coating layer 82_7 disposed in an alignment area AA, and the second coating layer 82_7 may include at least one coating pattern of 82a_7 and may be disposed between regions in which the first electrode <NUM> and the second electrode <NUM> are opposite to each other.

In <FIG>, the second coating layer 82_7 may include two coating patterns 82a_7, and the two coating patterns 82a_7 may be disposed between the first electrode branch portion 21B and the second electrode branch portion 22B. The coating pattern 82a_7 has a shape extending in the second direction Y-axis and is disposed to be spaced apart in the first direction X-axis. The coating pattern 82a_7 of the second coating layer 82_7 may be disposed between the first electrode branch portion 21B and the second electrode branch portion 22B and may apply an attractive force to allow the ink S to have low surface energy. That is, the ink S may spread to allow an area of an interface formed with the second coating layer 82_7 on the target substrate SUB to be increased, and the light emitting elements <NUM> included in the ink S may be located on the second coating layer 82_7. Most of the light emitting elements <NUM> in the ink S may be located between the first electrode branch portion 21B and the second electrode branch portion 22B to be disposed between the electrodes <NUM> and <NUM>.

Referring to <FIG>, when compared with <FIG>, the coating pattern 82a_8 of the second coating layer 82_8 may have a relatively larger width and may partially overlap one facing side surfaces of the first electrode branch portion 21B and the second electrode branch portion 22B. A description of the coating pattern 82a_8 is the same as the above description, and thus a detailed description thereof will be omitted herein.

Meanwhile, the display device <NUM> may further include a light emitting element <NUM> having a structure different from the structure of the light emitting element <NUM> of <FIG>.

<FIG> is a schematic diagram of a light emitting element according to another embodiment.

Referring to <FIG>, a light emitting element <NUM>' may be formed such that a plurality of layers are not stacked in one direction and each of the plurality of layers surrounds an outer surface of another layer. The light emitting element <NUM>' of <FIG> is the same as the light emitting element <NUM> of <FIG> except that shapes of the layers are partially different from each other. Hereinafter, the same content will be omitted and differences will be described.

According to one embodiment, a first conductivity type semiconductor <NUM>' may extend in one direction and both end portions thereof may be formed to be inclined toward a central portion thereof. The first conductivity type semiconductor <NUM>' of <FIG> may have a shape in which a rod-shaped or cylindrical main body and conical-shaped end portions on upper and lower portions of the main body are formed. An upper end portion of the main body may have a slope that is steeper than a slope of a lower end portion thereof.

An active layer <NUM>' is disposed to surround an outer surface of the main body of the first conductivity type semiconductor <NUM>'. The active layer <NUM>' may have an annular shape extending in one direction. The active layer <NUM>' may not be formed on upper and lower end portions of the first conductivity type semiconductor <NUM>'. That is, the active layer <NUM>' may be in contact with only a parallel side surface of the first conductivity type semiconductor <NUM>'.

A second conductivity type semiconductor <NUM>' is disposed to surround an outer surface of the active layer <NUM>' and the upper end portion of the first conductivity type semiconductor <NUM>'. The second conductivity type semiconductor <NUM>' may include an annular-shaped main body extending in one direction and an upper end portion having a side surface formed to be inclined. That is, the second conductivity type semiconductor <NUM>' may be in direct contact with a parallel side surface of the active layer <NUM>' and an inclined upper end portion of the first conductivity type semiconductor <NUM>'. However, the second conductivity type semiconductor <NUM>' is not formed in the lower end portion of the first conductivity type semiconductor <NUM>'.

An electrode material layer <NUM>' is disposed to surround an outer surface of the second conductivity type semiconductor <NUM>'. That is, a shape of the electrode material layer <NUM>' may be substantially the same as a shape of the second conductivity type semiconductor <NUM>'. That is, the electrode material layer <NUM>' may be entirely in contact with the outer surface of the second conductivity type semiconductor <NUM>'.

Claim 1:
A display device (<NUM>) comprising:
a substrate (SUB) in which a first area (AA) and a second area (NAA), which is an area other than the first area, are defined;
a first electrode (<NUM>) and a second electrode (<NUM>) disposed and at least partially spaced apart from each other in the first area on the substrate;
a first bank (<NUM>) disposed between the first electrode and the substrate;
a second bank (<NUM>) disposed between the second electrode and the substrate;
a first insulating layer (<NUM>) disposed to cover at least a portion of each of the first electrode and the second electrode on the substrate;
a coating layer (<NUM>) disposed on the first insulating layer; and
at least one light emitting element (<NUM>) disposed between the first electrode and the second electrode in the first area,
wherein the coating layer and the first insulating layer include an opening exposing at least a portion of each of the first electrode and the second electrode, and
the coating layer includes a first coating layer which is disposed in an area except for the opening and which includes a hydrophobic material.