Display device

A display device includes: a substrate; a first bank including a first sub-bank and a second sub-bank spaced apart from each other on the substrate; a first electrode on the first sub-bank; a second electrode on the second sub-bank and spaced apart from the first electrode; and a light-emitting element between the first sub-bank and the second sub-bank. Each of the first and second sub-banks has a first area having a concave curved shape in a cross section and being adjacent to the light-emitting element. The first electrode has a first section extending beyond the first sub-bank toward the light-emitting element, the second electrode has a first section extending beyond the second sub-bank toward the light-emitting element, and a width of the first section of the first electrode is different from a width of the first section of the second electrode.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2020-0176997, filed on Dec. 17, 2020, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

Aspects of embodiments of the present disclosure relate to a display device.

2. Description of the Related Art

Display devices become more and more important as multimedia technology evolves. Accordingly, a variety of types of display devices, such as organic light-emitting diode (OLED) display devices and liquid-crystal display (LCD) devices, are currently used.

Display devices generally include a display panel, such as an organic light-emitting display panel and a liquid-crystal display panel, for displaying images. Among them, light-emitting display panel may include light-emitting elements. For example, light-emitting diodes (LEDs) may include an organic light-emitting diode using an organic material as a luminescent material and an inorganic light-emitting diode using an inorganic material as a luminescent material.

SUMMARY

Embodiments of the present disclosure provide a display device including a sub-bank having an outer surface that faces a light-emitting element and has a concave curved shape.

Aspects and features of the present disclosure provide a display device having improved light output efficiency.

It should be noted that aspects and features of the present disclosure are not limited to those mentioned above; and other aspects and features of the present disclosure will be apparent to those skilled in the art from the following description.

According to an embodiment of the present disclosure, a display device includes: a substrate; a first bank including a first sub-bank and a second sub-bank spaced apart from each other on the substrate; a first electrode on the first sub-bank; a second electrode on the second sub-bank and spaced apart from the first electrode; and a light-emitting element between the first sub-bank and the second sub-bank. Each of the first and second sub-banks has a first area having a concave curved shape in a cross section and being adjacent to the light-emitting element. The first electrode has a first section extending beyond (or extending from) the first sub-bank toward the light-emitting element, the second electrode has a first section extending beyond the second sub-bank toward the light-emitting element, and a width of the first section of the first electrode is different from a width of the first section of the second electrode.

In an embodiment, an inclination angle of an outer surface of the first area of the first sub-bank and an inclination angle of an outer surface of the first area of the second sub-bank may increase along a thickness direction of the substrate.

In an embodiment, each of the first and second sub-banks may also have a second area having an inclination angle of an outer surface decreasing along the thickness direction of the substrate.

In an embodiment, the first electrode may be on the first sub-bank and formed along a surface shape of the first sub-bank, and the second electrode may be on the second sub-bank and formed along a surface shape of the second sub-bank.

In an embodiment, the first electrode may also have a second section on the first area of the first sub-bank, the second electrode may also have a second section on the first area of the second sub-bank, and each of the second section of the first electrode and the second section of the second electrode may have a concave curved shape in a cross section.

In an embodiment, each of the first electrode and the second electrode may include silver (Ag), aluminum (Al), or an alloy thereof.

In an embodiment, the second section of the first electrode and the second section of the second electrode may face both ends of the light-emitting element, respectively.

In an embodiment, the display device may further include a via layer on the substrate and having a flat surface, and the first sub-bank and the second sub-bank may be directly on the via layer.

In an embodiment, the first electrode may also have a second section on the first area of the first sub-bank and may have a concave curved shape in a cross section. The first section of the first electrode may be disposed on the via layer and may have a flat cross-sectional shape.

In an embodiment, the first section of the first electrode may extend from the second section of the first electrode.

In an embodiment, a height from a surface of the substrate to the first area of the first sub-bank may be greater than a height from the surface of the substrate to an upper surface of the light-emitting element.

In an embodiment, a first end of the light-emitting element may overlap the first section of the first electrode in a thickness direction of the substrate, a second end of the light-emitting element may overlap the first section of the second electrode in the thickness direction of the substrate, and a width of the first section of the first electrode may be greater than a width of the first section of the second electrode.

In an embodiment, a width at where the first end of the light-emitting element overlaps the first section of the first electrode in the thickness direction of the substrate may be greater than a width at where the second end of the light-emitting element overlaps the first section of the second electrode in the thickness direction of the substrate.

In an embodiment, the light-emitting element may include a first semiconductor layer, a second semiconductor layer spaced apart from the first semiconductor layer, and an active layer between the first semiconductor layer and the second semiconductor layer. The second semiconductor layer may be nearer to the first end of the light-emitting element than the second end of the light-emitting element, and the first semiconductor layer may be nearer to the second end of the light-emitting element than the first end of the light-emitting element.

In an embodiment, the active layer may be nearer to the first end of the light-emitting element from a center of the light-emitting element, and the first section of the first electrode may extend entirely under the second semiconductor layer and the active layer of the light-emitting element.

According to another embodiment of the present disclosure, a display device includes: a substrate; a via layer on the substrate; a first sub-bank on the via layer; a second sub-bank on the via layer and spaced apart from the first sub-bank; a first electrode on the first sub-bank; a second electrode on the second sub-bank; and a light-emitting element between the first sub-bank and the second sub-bank. Each of the first and second sub-banks has a first area facing both ends of the light-emitting element and having a concave curved shape in a cross section. The first electrode has a first section on the first area of the first sub-bank and a second section extending from the first section of the first electrode toward the light-emitting element, and the second electrode has a first section on the first area of the second sub-bank and a second section extending from the first section of the second electrode toward the light-emitting element. The second section of the first electrode and the second section of the second electrode are spaced apart from each other on the via layer, and a width of the second section of the first electrode is different from a width of the second section of the second electrode.

In an embodiment, the first electrode may be on the first sub-bank and on the via layer and may be formed along surface shapes of the first sub-bank and the via layer thereunder. The second electrode may be on the second sub-bank and the via layer and may be formed along surface shapes of the second sub-bank and the via layer thereunder.

In an embodiment, each of the first section of the first electrode and the first section of the second electrode may have a concave curved shape in a cross section, and each of the second section of the first electrode and the second section of the second electrode may be flat.

In an embodiment, the light-emitting element may include an active layer, the active layer may be nearer to a first end of the light-emitting element from a center of the light-emitting element, and the first end of the light-emitting element may face the first area of the first sub-bank.

In an embodiment, the second section of the first electrode may overlap the first end of the light-emitting element in a thickness direction of the substrate, the second section of the second electrode may overlap a second end of the light-emitting element in the thickness direction of the substrate, and a width of the second section of the first electrode may be greater than a width of the second section of the second electrode.

The details of one or more embodiments of the present disclosure are shown in the accompanying drawings and are descripted in the specification below.

The display device according to an embodiment may include a first bank that includes a plurality of sub-banks spaced apart from each other and having curved outer surfaces. A plurality of electrodes may be disposed on the sub-banks. The light-emitting diodes may be disposed between the sub-banks to be electrically connected to the electrodes. The plurality of sub-banks may have a first area having a concave outer surface on one side facing the light-emitting diode such that light emitted from the light-emitting diode is reflected by the surface of the electrode disposed on the first area of the sub-bank. Because the outer surface of the sub-bank that faces the light-emitting diode has a concave curved shape, the amount of light emitted from the light-emitting diode and directed toward the display side (or display surface) of the display device is increased and the light collection efficiency is improved. As a result, the output efficiency of the display device can be improved.

It should be noted that aspects and features of the present disclosure are not limited to those described above and other aspects and features of the present disclosure will be apparent to those skilled in the art from the following descriptions.

DETAILED DESCRIPTION

FIG.1is a plan view of a display device according to an embodiment of the present disclosure.

Referring toFIG.1, a display device10is configured to display a moving image or a still image. The display device10may refer to any electronic device that provides (or includes) a display screen. For example, the display device10may include a television set, a laptop computer, a monitor, an electronic billboard, an Internet of Things (IoT) device, a mobile phone, a smart phone, a tablet personal computer (PC), an electronic watch, a smart watch, a watch phone, a head-mounted display device, a mobile communications terminal, an electronic notebook, an electronic book, a portable multimedia player (PMP), a navigation device, a game console and a digital camera, a camcorder, etc.

The display device10includes a display panel for providing a display screen. Examples of the display panel may include an inorganic light-emitting diode display panel, an organic light-emitting diode display panel, a quantum-dot light-emitting display panel, a plasma display panel, a field emission display panel, etc. In the following description, the display device10is described as an inorganic light-emitting diode display panel, but the present disclosure is not limited thereto. Other suitable display panels may be employed as long as the technical idea of the present disclosure can be equally applied thereto.

A first direction DR1, a second direction DR2, and a third direction DR3are defined in the drawings. The display device10according to embodiments of the present disclosure will be described with reference to the drawings. The first direction DR1may be perpendicular to the second direction DR2in a plane The third direction DR3may be perpendicular to the plane in which the first direction DR1and the second direction DR2are located. The third direction DR3may be perpendicular to each of the first direction DR1and the second direction DR2. In the following description of the display device10according to embodiments of the present disclosure, the third direction DR3refers to the thickness direction (e.g., the display side or display direction) of the display device10.

The display device10may have a rectangular shape having longer sides in the first direction DR1and shorter sides in the second direction DR2when viewed from the top. Although the corners at where the longer sides and the shorter sides of the display device10meet may form a right angle, this is merely illustrative. The display device10may have rounded corners. The shape of the display device10is not limited to that shown and may be modified in a variety of ways. For example, the display device10may have other shapes, such as a square, a rectangle with rounded corners (vertices), other polygons, and a circle.

A display surface may be located on one side of the display device10in the third direction DR3(e.g., the thickness direction). In the following description, the upper side of the display device10refers to the side in the third direction DR3where images are displayed, and the upper surface of the display device10refers to the surface facing in the third direction DR3, unless specifically stated otherwise. In addition, the lower side refers to the opposite side in the third direction DR3, and likewise the lower surface refers to the surface facing the opposite direction to the third direction DR3. As used herein, the terms “left,” “right,” “upper,” and “lower” sides refer to relative positions when the display device10is viewed from the top. For example, the right side refers to one side in the first direction DR1, the left side refers to the opposite side in the first direction DR1, the upper side refers to one side in the second direction DR2, and the lower side refers to the opposite side in the second direction DR2.

The display device10may have a display area DPA and a non-display area NDA. Images can be displayed in the display area DPA. Images are not displayed in the non-display area NDA.

The shape of the display area DPA may follow the shape of the display device10. For example, the display area DPA may have a rectangular shape generally similar to the shape of the display device10when viewed from the top. The display area DPA may generally occupy the majority of the center of the display device10.

The display area DPA may include a plurality of pixels PX. The plurality of pixels PX may be arranged in a matrix. The shape of each of the pixels PX may be rectangular or square when viewed from the top. In an embodiment, each of the pixels PX may include a plurality of light-emitting elements including (or made of) inorganic particles.

The non-display area NDA may be disposed around the display area DPA. The non-display area NDA may entirely or partially surround (e.g., may extend around a periphery of) the display area DPA. The non-display area NDA may form the bezel of the display device10.

FIG.2is a schematic plan view showing a pixel of a display device according to an embodiment of the present disclosure, andFIG.3is a plan view showing a sub-pixel of a display device according to an embodiment of the present disclosure.

Referring toFIG.2, each of the pixels PX may include a plurality of sub-pixels SPX: SPX1, SPX2, and SPX3. For example, a pixel PX may include a first sub-pixel SPX1, a second sub-pixel SPX2, and a third sub-pixel SPX3. The first sub-pixel SPX1may emit light of a first color, the second sub-pixel SPX2may emit light of a second color, and the third sub-pixel SPX3may emit light of a third color. The first color may be blue, the second color may be green, and the third color may be red. It is, however, to be understood that the present disclosure is not limited thereto. The sub-pixels SPX1, SPX2and SPX3may emit light of the same color. Although the single pixel PX includes three sub-pixels SPX1, SPX2and SPX3in the example shown inFIG.2, the present disclosure is not limited thereto. Each pixel PX may include more than three sub-pixels SPX.

Each of the sub-pixels SPX of the display device10may have an emission area EMA and a non-emission area. Light emitted from the light-emitting diodes ED may exit from the emission area EMA. Light emitted from the light-emitting diodes ED do not reach and, thus, no light exits from the non-emission area.

The emission area EMA may include an area where the light-emitting diodes ED are disposed and an area adjacent thereto. The emission area EMA may further include an area (e.g., the area adjacent to the area where the light-emitting diodes ED are disposed) in which light emitted from the light-emitting diodes ED is reflected or refracted by other elements to exit.

Each of the sub-pixels SPX may further include a subsidiary area SA disposed in the non-emission area. No light-emitting diodes ED may be disposed in the subsidiary area SA. The subsidiary area SA may be disposed at the upper side of the emission area EMA (e.g., at one side of the emission area EMA in the second direction DR2) within one pixel PX. The subsidiary area SA may be disposed between the emission areas EMA of neighboring pixels PX in the second direction DR2.

The subsidiary area SA may include a separation region ROP. In the separation region ROP of the subsidiary area SA, a first electrode210and a second electrode220included in a sub-pixel SPX may be separated from a first electrode210and a second electrode220included in another sub-pixel SPX adjacent to the sub-pixel SPX in the second direction DR2, respectively. Accordingly, portions of the first electrode210and the second electrode220disposed in each of the sub-pixels SPX may be disposed in the subsidiary area SA.

Referring toFIGS.2and3, each sub-pixel SPX of the display device10according to an embodiment may include a plurality of electrodes210and220, a first bank400including a plurality of sub-banks, a plurality of contact electrodes710and720, a plurality of light-emitting diodes ED, and a second bank600.

Hereinafter, referring toFIGS.2and3, the arrangement structure of the plurality of electrodes210and220, the first bank400including the plurality of sub-banks, the plurality of contact electrodes710and720, the plurality of light-emitting diodes ED, and the second bank600included in a single sub-pixel SPX of the display device10according to an embodiment of the present disclosure when viewed from the top will be described.

The second bank600may be disposed in a lattice pattern on the entire surface in the display area DPA and may have portions extended in the first direction DR1and the second direction DR2when viewed from the top. The second bank600may be disposed along the border of each of the sub-pixels SPX to distinguish adjacent sub-pixels SPX from one another. The second bank600may be disposed to surround (e.g., to extend around a periphery of) the emission area EMA and the subsidiary area SA within each of the sub-pixels SPX to distinguish between them. For example, the emission area EMA and the subsidiary area SA in each of the sub-pixels SPX may be defined by the second bank600.

The first bank400may be disposed in the emission area EMA. The first bank400may have a shape extended in the second direction DR2in the emission area EMA. The first bank400may be extended in the second direction DR2and may be spaced apart from the second bank600surrounding the emission area EMA. For example, the length of the first bank400in the second direction DR2may be smaller than the length of the emission area EMA surrounded by the second bank600in the second direction DR2.

The first bank400may include a plurality of sub-banks410and420disposed to face each other in the emission area EMA. Because the plurality of sub-banks410and420are spaced apart from each other, the plurality of sub-banks410and420may provide a space in which the light-emitting diodes ED are disposed therebetween (e.g., the light-emitting diodes ED may be disposed in an area between the plurality of sub-banks410and420). In addition, as will be described in more detail later, each of the plurality of sub-banks410and420has an outer surface that faces the light-emitting diode ED and has a concave curved shape such that it also acts as a reflective partition wall that changes the direction in which the light emitted from the light-emitting diode ED travels to be toward the display side.

The first bank400may include a first sub-bank410and a second sub-bank420. The first sub-bank410and the second sub-bank420may be spaced apart from each other and face each other in the first direction DR1. For example, the first sub-bank410may be disposed on the left side of the emission area EMA when viewed from the top, and the second sub-bank420may be disposed on the right side of the emission area EMA when viewed from the top.

Although the first bank400included in one sub-pixel SPX includes two sub-banks (e.g., the first and second sub-banks410and420) in the illustrated embodiment, the number of the plurality of sub-banks included in one sub-pixel SPX is not limited thereto. For example, the first bank400included in one sub-pixel SPX may include more than two sub-banks depending on the number of the electrodes210and220.

The electrodes210and220may include a first electrode210and a second electrode220. The first electrode210and the second electrode220may be spaced apart from and face each other in the first direction DR1.

The first electrode210may be disposed on the first sub-bank410. The first electrode210may be disposed on the left side of each of the sub-pixels SPX when viewed from the top. The first electrode210may have a shape extended in the second direction DR2when viewed from the top. The first electrode210may be disposed such that it passes through the emission area EMA. The first electrode210may be separated from the first electrode210of another sub-pixel SPX adjacent to it in the second direction DR2at the separation region ROP of the subsidiary area SA.

The second electrode220may be disposed on the second sub-bank420. The second electrode220may be spaced apart from the first electrode210in the first direction DR1. The second electrode220may be spaced apart from and face the first electrode210in the first direction DR1. The second electrode220may be disposed on the right side of each of the sub-pixels PX when viewed from the top. The second electrode220may have a shape extended in the second direction DR2when viewed from the top. The second electrode220may be disposed to pass through the emission area EMA. The second electrode220may be separated from the second electrode220of another sub-pixel SPX adjacent to it in the second direction DR2at the separation region ROP of the subsidiary area SA.

In some embodiments, the first electrode210and the second electrode220may be formed to have larger widths than the first sub-bank410and the second sub-bank420, respectively. For example, the width of the first electrode210in the first direction DR1may be larger than the width of the first sub-bank410in the first direction DR1, and the width of the second electrode220in the first direction DR1may be larger than the width of the second sub-bank420in the first direction DR1. Accordingly, the distance between the first electrode210and the second electrode220in the first direction DR1, when viewed from the top, may be smaller than the distance between the first sub-bank410and the second sub-bank420in the first direction DR1.

The first electrode210and the second electrode220may be disposed to cover outer surfaces of the first and second sub-banks410and420, respectively.

The first electrode210may cover the first sub-bank410to extend outwardly therefrom and may be disposed such that one side surface thereof that faces the second electrode220(e.g., the right side of the first electrode210when viewed from the top) is located between the first sub-bank410and the second sub-bank420. Similarly, the second electrode220may cover the outer surface of the second sub-bank420to extend outwardly therefrom and may be disposed such that one side surface thereof that faces the first electrode210(e.g., the left side of the second electrode220when viewed from the top) is located between the first sub-bank410and the second sub-bank420.

The width d1of the portion of the first electrode210extended from the first sub-bank410into the area between the first sub-bank410and the second sub-bank420may be equal to a first horizontal distance d1between the right side of the first electrode210and the right side of the first sub-bank410. The right side of the first electrode210may be one side of the first electrode210that faces the second electrode220. The right side of the first sub-bank410may be one side of the first sub-bank410that faces the second sub-bank420or one side of the first sub-bank410that faces a first end of the light-emitting diode ED, to be described later.

Similarly, the width d2of the portion of the second electrode220extended from the second sub-bank420into the area between the first sub-bank410and the second sub-bank420may be equal to a second horizontal distance d2between the left side of the second electrode220and the left side of the second sub-bank420. The left side of the second electrode220may be one side of the second electrode220that faces the first electrode210. The left side of the second sub-bank420may be one side of the second sub-bank420that faces the first sub-bank410or one side of the second sub-bank420that faces a second end of the light-emitting diode ED, to be described later, which is the opposite end to the first end.

The first horizontal distance d1between the right side of the first electrode210and the right side of the first sub-bank410may be different from the second horizontal distance d2between the left side of the second electrode220and the left side of the second sub-bank420. For example, the width d1of the portion of the first electrode210extended from the first sub-bank410into the area between the first sub-bank410and the second sub-bank420may be different from the width d2of the portion of the second electrode220extended from the second sub-bank420into the area between the first sub-bank410and the second sub-bank420. For example, the first horizontal distance d1between the right side of the first electrode210and the right side of the first sub-bank410may be greater than the second horizontal distance d2between the left side of the second electrode220and the left side of the second sub-bank420. When the width d1of the portion of the first electrode210extended from the first sub-bank410into the area between the first sub-bank410and the second sub-bank420is different from the width d2of the portion of the second electrode220extended from the second sub-bank420into the area between the first sub-bank410and the second sub-bank420, the width of the portion of the electrode210that overlaps the light-emitting diode ED may be different from the width of the portion of the second electrode220that overlaps the light-emitting diode ED, which will be described in more detail later.

InFIGS.2and3, which illustrate the structure of the display device10when viewed from the top, the first horizontal distance d1when viewed from the top is defined as “horizontal distance d1between the right side of the first electrode210and the right side of the first sub-bank410” or as “the width d1of the portion of the first electrode210extended from the first sub-bank410into the area between the first sub-bank410and the second sub-bank420”. InFIG.7, which illustrates the cross-sectional structure of the display device10, and which will be described later, the same reference numeral “d1” may be defined as “the width d1of the portion of the first electrode210that protrudes from the first sub-bank410into the area between the first sub-bank410and the second sub-bank420” in a cross section. Likewise, the second horizontal distance d2when viewed from the top is defined as “horizontal distance d2between the left side of the second electrode220and the left side of the second sub-bank420” or as “the width d2of the portion of the second electrode220extended from the second sub-bank420into the area between the first sub-bank410and the second sub-bank420”. InFIG.7, which illustrates the cross-sectional structure of the display device10, and which will be described later, the same reference numeral “d2” may be defined as “the width d2of the portion of the second electrode220that protrudes from the second sub-bank420into the area between the first sub-bank410and the second sub-bank420” in a cross section.

The light-emitting diodes ED may be disposed between the first sub-bank410and the second sub-bank420. The plurality of light-emitting diodes ED may have a shape extended in one direction and may be disposed such that both ends (e.g., opposite ends) thereof face the first sub-bank410and the second sub-bank420, respectively, between the first sub-bank410and the second sub-bank when viewed from the top. For example, the plurality of light-emitting diodes ED may be disposed such that the first ends of the light-emitting diodes ED face one side of the first sub-bank410(e.g., the right side of the first sub-bank410when viewed from the top) and the second ends of the light-emitting diodes ED face one side of the second sub-bank420(e.g., the left side of the second sub-bank420when viewed from the top).

The light-emitting diodes ED may be disposed generally at the center between (e.g., substantially equidistant between) the first sub-bank410and the second sub-bank420. For example, a third horizontal distance d3between the first sub-bank410and the light-emitting diodes ED may be equal or substantially equal to a fourth horizontal distance d4between the second sub-bank420and the light-emitting diodes ED. The third horizontal distance d3between the first sub-bank410and the light-emitting diode element ED may be measured as the horizontal distance d3between the right side of the first sub-bank410and the first end of the light-emitting diodes ED. The fourth horizontal distance d4between the second sub-bank420and the light-emitting diode ED may be measured as the horizontal distance d4between the left side of the second sub-bank420and the second end of the light-emitting diode ED. It is, however, to be understood that the present disclosure is not limited thereto. Some of the plurality of light-emitting diodes ED may be disposed closer to one of the sub-banks410and420between the first sub-bank410and the second sub-bank420.

The plurality of light-emitting diodes ED may be disposed such that both ends of the light-emitting diodes ED are placed on the first electrode210and the second electrode220, respectively, between the first sub-bank410and the second sub-bank420. For example, the plurality of light-emitting diodes ED may be disposed such that the first ends of the light-emitting diodes ED are on the first electrode210while the second ends of the light-emitting diodes ED are on the second electrode220.

The first electrode210may at least partially overlap the first ends of the light-emitting diodes ED in the third direction DR3. The width w1at where the first electrode210overlaps the first ends of the light-emitting diodes ED in the third direction DR3may be equal to a fifth horizontal distance w1between the left side of the first electrode210and the first ends of the light-emitting diodes ED.

The second electrode220may at least partially overlap the second ends of the light-emitting diodes ED in the third direction DR3. The width w2at where the second electrode220overlaps the second ends of the light-emitting diodes ED in the third direction DR3may be equal to a sixth horizontal distance w2between the right side of the second electrode220and the second ends of the light-emitting diodes ED.

The widths w1and w2at where the both ends of the light-emitting diodes ED overlap the first electrode210and the second electrode220in the third direction DR3, respectively, may be different from each other. For example, the light-emitting diodes ED are disposed at the center between the first sub-bank410and the second sub-bank420, which are spaced apart from each other. When the width d1of the portion of the first electrode210extended from the first sub-bank410into the area between the first sub-bank410and the second sub-bank420is different from the width d2of the portion of the second electrode220extended from the second sub-bank420into the area between the first sub-bank410and the second sub-bank420, the widths w1and w2at where the both ends of the light-emitting diodes ED overlap the first electrode210and the second electrode220in the third direction DR3, respectively, may be different from each other. For example, the width w1at where the first ends of the light-emitting diodes ED overlap the first electrode210in the third direction DR3may be different from the width w2at where the second ends of the light-emitting diodes ED overlap the second electrode220in the third direction DR3. For example, the width w1at where the first ends of the light-emitting diodes ED overlap the first electrode210in the third direction DR3may be larger than the width w2at where the second ends of the light-emitting diodes ED overlap the second electrode220in the third direction DR3.

When the width d1of the portion of the first electrode210extended from the first sub-bank410into the area between the first sub-bank410and the second sub-bank420is different from the width d2of the portion of the second electrode220extended from the second sub-bank420into the area between the first sub-bank410and the second sub-bank420, the arrangement of the first electrode210, the second electrode220, and the light-emitting diodes ED may be controlled such that the widths w1and w2at where the both ends of the light-emitting diodes ED overlap the first electrode210and the second electrode220in the third direction DR3, respectively, are different from each other.

The contact electrodes710and720may include a first contact electrode710and a second contact electrode720. The first contact electrode710and the second contact electrode720may be spaced apart from each other.

The first contact electrode710may be disposed on the first electrode210. The first contact electrode710may have a shape extended in the second direction DR2. The first contact electrode710may contact the first electrode210and the first ends of the light-emitting diodes ED. The first contact electrode710may contact the first electrode210at an area exposed by a first opening OP1in the subsidiary area SA and may contact the first ends of the light-emitting diode ED in the emission area EMA. The first contact electrode710may electrically connect the first end of the light-emitting diode ED with the first electrode210.

The second contact electrode720may be disposed on the second electrode220. The second contact electrode720may have a shape extended in the second direction DR2. The second contact electrode720may contact the second electrode220and the second ends of the light-emitting diodes ED. The second contact electrode720may contact the second electrode220at an area exposed by a second opening OP2in the subsidiary area SA and may contact the second ends of the light-emitting diodes ED in the emission area EMA. The second contact electrode720may electrically connect the second ends of the light-emitting diodes ED with the second electrode220.

FIG.4is a cross-sectional view taken along the lines Q1-Q1′, Q2-Q2′, and Q3-Q3′ ofFIG.3, andFIG.5is a cross-sectional view taken along the line Q4-Q4′ ofFIG.3.

Referring toFIG.4, the display device10may include a substrate SUB, a circuit element layer CCL disposed on the substrate SUB, the plurality of electrodes210and220disposed on the circuit element layer CCL, the first bank400including the plurality of sub-banks, and a display elements layer including the plurality of contact electrodes710and720, the plurality of light-emitting diodes ED, the second bank600, and a display element layer including a plurality of insulating layers.

The substrate SUB may be an insulating substrate. The substrate SUB may include (or may be made of) an insulating material, such as glass, quartz, and a polymer resin. The substrate SUB may be a rigid substrate or a flexible substrate that can be bent, folded, or rolled.

The circuit element layer CCL may be disposed on the substrate SUB. The circuit element layer CCL may include a plurality of conductive layers, at least one transistor TR, a plurality of insulating layers, and first and second voltage lines VL1and VL2.

A bottom metal layer110may be disposed on the substrate SUB. The bottom metal layer110may be a light-blocking layer that protects an active layer ACT of the transistor TR. The bottom metal layer110may include a material that blocks (or substantially blocks) light. For example, the bottom metal layer110may include (or may be made of) an opaque metal material that blocks light transmission.

The bottom metal layer110may be disposed under and may cover at least a channel region of the active layer ACT of the transistor TR and, in some embodiments, may cover the entire active layer ACT of the transistor TR. It is, however, to be understood that the present disclosure is not limited thereto. The bottom metal layer110may be omitted.

A buffer layer161may be disposed over the bottom metal layer110. The buffer layer161may be disposed to cover the entire surface of the substrate SUB on which the bottom metal layer110is disposed. The buffer layer161may protect a plurality of transistors from moisture permeating through the substrate SUB, which may be vulnerable to moisture permeation.

The semiconductor layer is disposed on the buffer layer161. The semiconductor layer may include the active layer ACT of the transistor TR. The active layer ACT of the transistor TR may be disposed to overlap the bottom metal layer110as described above.

The semiconductor layer may include polycrystalline silicon, monocrystalline silicon, an oxide semiconductor, etc. According to an embodiment of the present disclosure, when the semiconductor layer includes polycrystalline silicon, the polycrystalline silicon may be formed by crystallizing amorphous silicon. When the semiconductor layer includes polycrystalline silicon, the active layer ACT of the transistor TR may include a plurality of doped regions doped with impurities and a channel region between them. In another embodiment, the semiconductor layer may include an oxide semiconductor. For example, the oxide semiconductor may be indium-tin oxide (ITO), indium-zinc oxide (IZO), indium-gallium oxide (IGO), indium-zinc-tin oxide (IZTO), indium-gallium-zinc oxide (IGZO), indium-gallium-tin oxide (IGTO), indium-gallium-zinc-tin oxide (IGZTO), etc.

A gate insulator162may be disposed on the semiconductor layer. The gate insulator162may act as a gate insulating layer of each transistor. The gate insulator162may include (or may be made up of) a plurality of layers in which inorganic layers including inorganic material (e.g., at least one of silicon oxide (SiOx), silicon nitride (SiNx) and silicon oxynitride (SiOxNy)) are stacked on one another alternately.

A first conductive layer may be disposed on the gate insulator162. The first conductive layer may include a gate electrode GE of the transistor TR. The gate electrode GE of the transistor TR may be disposed so that it overlaps a channel region of the active layer ACT of the transistor TR in the thickness direction (e.g., the third direction DR3).

A first interlayer dielectric layer163may be disposed on the first conductive layer. The first interlayer dielectric layer163may cover the gate electrode GE of the transistor TR. The first interlayer dielectric layer163may act as an insulating layer between the first conductive layer and other layers disposed thereon and may protect the first conductive layer.

A second conductive layer may be disposed on the first interlayer dielectric layer163. The second conductive layer may include a source electrode SD1and a drain electrode SD2of the transistor TR. The second conductive layer may further include a data line.

The source electrode SD1and the drain electrode SD2of the transistor TR may be electrically connected to both end regions of the active layer ACT of the transistor TR through contact openings (e.g., contact holes) penetrating the first interlayer dielectric layer163and the gate insulator162, respectively. In addition, the source electrode SD1may be electrically connected to the bottom metal layer110through another contact opening (e.g., another contact hole) penetrating through the first interlayer dielectric layer163, the gate insulator162, and the buffer layer161.

A second interlayer dielectric layer164may be disposed on the second conductive layer. The second interlayer dielectric layer164may act as an insulating layer between the second conductive layer and other layers disposed thereon and may protect the second conductive layer.

A third conductive layer may be disposed on the second interlayer dielectric layer164. The third conductive layer may include a first voltage line VL1, a second voltage line VL2, and a first conductive pattern CDP.

A high-level voltage (e.g., a first supply voltage) may be applied to the first voltage line VL1to be supplied to the first transistor TR, and a low-level voltage (e.g., a second supply voltage), which is lower than the high-level voltage supplied to the first voltage line VL, may be applied to the second voltage line VL21.

The first voltage line VL1may be electrically connected to the drain electrode SD2of the transistor TR through a contact opening (e.g., contact hole) penetrating the second interlayer dielectric layer164.

The second voltage line VL2may be electrically connected to the second electrode220through a second electrode contact opening (e.g., a second electrode contact hole) CT2penetrating through a via layer165, to be described later. The second supply voltage applied to the second voltage line VL2may be supplied to the second electrode220. An alignment signal for aligning the light-emitting diodes ED during the process of fabricating the display device10may be applied to the second voltage line VL2.

The first conductive pattern CDP may be electrically connected to the transistor TR. The first conductive pattern CDP may be electrically connected to the source electrode SD1of the transistor TR through a contact opening (e.g., a contact hole) penetrating the second interlayer dielectric layer164. In addition, the first conductive pattern CDP may be electrically connected to the first electrode210through a first electrode contact opening (e.g., a first electrode contact hole) CT1penetrating through the via layer165. The transistor TR may transmit the first supply voltage applied from the first voltage line VL1to the first electrode210through the first conductive pattern CDP.

The via layer165may be disposed on the third conductive layer. The via layer165may be disposed on the second interlayer dielectric layer164on which the third conductive layer is disposed. The via layer165may include an organic insulating material, for example, an organic material, such as polyimide (PI). The via layer165may provide a flat surface.

The buffer layer161, the gate insulator162, the first interlayer dielectric layer163, and the second interlayer dielectric layer164may include (or may be made up of) a plurality of inorganic layers stacked on one another alternately. For example, the buffer layer161, the gate insulator162, the first interlayer dielectric layer163, and the second interlayer dielectric layer164may include (or may be made up of) a double layer in which inorganic layers including at least one of silicon oxide (SiOx), silicon nitride (SiNx) and silicon oxynitride (SiON) are stacked on one another or may include (or may be made up of) a plurality of layers in which they are alternately stacked on one another. It is, however, to be understood that the present disclosure is not limited thereto. The buffer layer161, the gate insulator162, the first interlayer dielectric layer163, and the second interlayer dielectric layer164may include (or may be made up of) a single inorganic layer including the above-described insulating material(s).

The first conductive layer, the second conductive layer, and the third conductive layer may include (or may be made up of) a single layer or a plurality of layers of one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu), or an alloy thereof. It is, however, to be understood that the present disclosure is not limited thereto.

The display element layer may be disposed on the via layer165. Hereinafter, a structure of the display element layer disposed on the circuit element layer CCL will be described with reference toFIGS.3to5.

The first bank400may be disposed on the via layer165in the emission area EMA. The first bank400may have a shape protruding in the thickness direction of the substrate SUB (e.g., the third direction DR3) with respect to one surface of the via layer165.

Each of the first sub-bank410and the second sub-bank420may be disposed on one surface of the via layer165. Each of the first sub-bank410and the second sub-bank420may have a shape protruding in the thickness direction of the substrate SUB with respect to the surface of the via layer165.

According to an embodiment of the present disclosure, each of the first sub-bank410and the second sub-bank420may have a shape protruding from the via layer165and may have at least a partially a concave curved shape. As used herein, the expression “concave curved shape” may refer to a shape of an element in which an outer surface is recessed toward the inner side of the element and curved in cross section, or a shape of an element in which the slope of a tangent line on an outer surface of the element increases along the third direction DR3. In addition, the expression “convex curved shape” may refer to a shape of an element in which an outer surface protrudes toward the outer side of the element and curved in cross section, or a shape of an element in which the slope of a tangent line on an outer surface of the element decreases along the third direction DR3.

The first sub-bank410may have a first area410A and a second area410B that are distinguished by their arrangement relationships with the ends of the light-emitting diodes ED and their cross-sectional shapes.

The first area410A of the first sub-bank410may face the first ends of the light-emitting diodes ED and may have a concave curved shape in a cross section. The first area410A of the first sub-bank410may be located on one side (e.g., the right side in the drawing) facing the first ends of the light-emitting diodes ED. Accordingly, the first area410A of the first sub-bank410may be located on one side facing the second sub-bank420. The first area410A of the first sub-bank410may have a shape that is recessed inwardly and curved in the cross section of the first sub-bank410.

The second area410B of the first sub-bank410may be located on the opposite side to the side facing the first ends of the light-emitting diodes ED and may have a convex curved shape. The second area410B of the first sub-bank410may be located on the opposite side (e.g., the left side in the drawing) to the side facing the first ends of the light-emitting diodes ED. The second area410B of the first sub-bank410may face the second bank600. The second area410B of the first sub-bank410may have a shape that protrudes outwardly and is curved in the cross section of the first sub-bank410. Although the second area410B of the first sub-bank410has a convex curved shape in the cross section in the drawings, the present disclosure is not limited thereto. For example, the second area410B of the first sub-bank410may have an at least partially inclined side surface, or may have an at least partially concave curved shape in the cross section, similar to the first area410A of the first sub-bank410.

The second sub-bank420may have a first area420A and a second area420B that are distinguished by their arrangement relationships with the ends of the light-emitting diodes ED and their cross-sectional shapes.

The first area420A of the second sub-bank420may face the second ends of the light-emitting diodes ED and may have a concave curved shape in a cross section. The first area420A of the second sub-bank420may be located on one side (e.g., the left side in the drawing) facing the second ends of the light-emitting diodes ED. Accordingly, the first area420A of the second sub-bank420may be located on one side facing the first sub-bank410and may face the first area410A of the first sub-bank410. The first area420A of the second sub-bank420may have a shape that is recessed inwardly and curved in the cross section of the second sub-bank420.

The second area420B of the second sub-bank420may be located on the opposite side to the side facing the second ends of the light-emitting diodes ED and may have a convex curved shape. The second area420B of the second sub-bank420may be located on the opposite side (e.g., the right side in the drawing) to the side facing the second ends of the light-emitting diodes ED. The second area420B of the second sub-bank420may have a shape that protrudes outwardly and is curved in the cross section of the second sub-bank420. Although the second area420B of the second sub-bank420has a convex curved shape in the cross section in the drawings, the present disclosure is not limited thereto. For example, the second area420B of the second sub-bank420may have an at least partially inclined side surface, or may have an at least partially concave curved shape in the cross section, similar to the first area420A of the second sub-bank420.

According to an embodiment of the present disclosure, the first bank400may include, but is not limited to, an organic insulating material, such as polyimide (PI).

The first electrode210and the second electrode220may be disposed on the first bank400and the via layer165exposed by the first bank400. The first electrode210and the second electrode220may be electrically connected to the circuit element layer CCL disposed therebelow.

The first electrode210may be connected to the first conductive pattern CDP through the first electrode contact opening CT1penetrating the via layer165. For example, the first electrode210may contact the first conductive pattern CDP through the first electrode contact opening CT1penetrating the via layer165. The first electrode contact opening CT1may overlap the second bank600in the third direction DR3, but the position of the first electrode contact opening CT1is not limited thereto.

The second electrode220may be connected to the second voltage line VL2through the second electrode contact opening CT2penetrating the via layer165. For example, the second electrode220may contact the second voltage line VL2through the second electrode contact opening CT2penetrating the via layer165. The second electrode contact opening CT2may be spaced apart from the first electrode contact opening CT1and may overlap the second bank600in the third direction DR3, but the position of the second electrode contact opening CT2is not limited thereto.

The first electrode210may be electrically connected to the transistor TR through the first conductive pattern CDP to receive the first supply voltage. The second electrode220may be electrically connected to the second voltage line VL2to receive the second supply voltage. Because the first electrode210and the second electrode220are disposed separately in each of the sub-pixels PXn, the light-emitting diodes ED of different sub-pixels PXn may individually emit light.

The first electrode210may be disposed on the first sub-bank410. The first electrode210may be disposed on the first sub-bank410to cover an outer surface of the first sub-bank410. The first electrode210may be extended outwardly from the first sub-bank410and may be partially disposed on the surface of the via layer165exposed by (e.g., beyond the periphery of) the first sub-bank410and the second sub-bank420between the first sub-bank410and the second sub-bank420.

The first electrode210may be disposed on the first sub-bank410and the via layer165. The first electrode210may be disposed on the first sub-bank410and the via layer165and formed along the surface shape of the first sub-bank410and the via layer165disposed thereunder. Accordingly, the cross-sectional shape of the surface of the first electrode210disposed on the first sub-bank410may have a shape conforming to the shape of the outer surface (or surface) of the first sub-bank410. In addition, a cross-sectional shape of the surface of the first electrode210disposed on the via layer165may have a shape conforming to the shape of the surface of the via layer165. For example, the cross-sectional shape of the surface of the first electrode210disposed on the first sub-bank410may have a concave curved shape where it overlaps the first area410A of the first sub-bank410in the third direction DR3and a convex curved shape where it overlaps the second area410B of the first sub-bank410in the third direction DR3. In addition, the cross-sectional shape of the surface of the first electrode210disposed on the via layer165may be flat where it overlaps the via layer165in the third direction DR3.

The second electrode220may be disposed on the second sub-bank420. The second electrode220may be disposed on the second sub-bank420to cover an outer surface of the second sub-bank420. The second electrode220may be extended outwardly from the second sub-bank420and may be partially disposed on the surface of the via layer165exposed by (e.g., beyond the periphery of) the first sub-bank410and the second sub-bank420between the first sub-bank410and the second sub-bank420. The first electrode210and the second electrode220disposed between the first sub-bank410and the second sub-bank420may be spaced apart from each other on the via layer165.

The second electrode220may be disposed on the second sub-bank420and the via layer165. The second electrode220may be disposed on the second sub-bank420and the via layer165and formed along the surface shape of the second sub-bank420and the via layer165. Accordingly, the cross-sectional shape of the surface of the second electrode220disposed on the second sub-bank420may have a shape conforming to the shape of the outer surface (or surface) of the second sub-bank420. In addition, a cross-sectional shape of the surface of the second electrode220disposed on the via layer165may have a shape conforming to the shape of the surface of the via layer165. For example, the cross-sectional shape of the surface of the second electrode220disposed on the second sub-bank420may have a concave curved shape where it overlaps the first area420A of the second sub-bank420in the third direction DR3and a convex curved shape where it overlaps the second area420B of the second sub-bank420in the third direction DR3. In addition, the cross-sectional shape of the surface of the second electrode220disposed on the via layer165may be flat where it overlaps the via layer165in the third direction DR3.

Each of the first and second electrodes210and220may be electrically connected to the light-emitting diode ED. The first and second electrodes210and220may be connected to both ends of the light-emitting diode ED through contact electrodes710and720, respectively, and may transmit electric signals applied from the circuit element layer CCL to the light-emitting diode ED.

Each of the first and second electrodes210and220may include a conductive material having high reflectance (e.g., a highly-reflective conductive material). For example, the first and second electrodes210and220may include a metal, such as silver (Ag), copper (Cu), and aluminum (Al) as the material having high reflectance, or may include an alloy including aluminum (Al), nickel (Ni), lanthanum (La), etc. The first and second electrodes210and220may reflect light that is emitted by the light-emitting diodes ED and travels (or propagates) to the outer surface of the first bank400at the surfaces of the first and second electrodes210and220, respectively, which is then reflected toward the upper side of each of the sub-pixels SPX. The direction in which the light emitted by the light-emitting diodes ED travels will be described in more detail later.

It is, however, to be understood that the present disclosure is not limited thereto. Each of the first and second electrodes210and220may further include a transparent conductive material. For example, the first and second electrodes210and220may include a material, such as ITO, IZO, and ITZO. In some embodiments, the first and second electrodes210and220may have a structure in which one or more layers of a transparent conductive material and a metal layer having high reflectivity are stacked or may include (or may be made up of) a single layer including them. For example, each of the first and second electrodes210and220may have a stacked structure, such as ITO/Ag/ITO/, ITO/Ag/IZO, and ITO/Ag/ITZO/IZO.

A first insulating layer510may be disposed on the first and second electrode210and220. The first insulating layer510may be disposed on the first and second electrode210and220to cover them. The first insulating layer510may protect the first electrode210and the second electrode220and insulate them from each other. In addition, the first insulating layer510may prevent or substantially prevent the light-emitting diode ED disposed thereon to be brought into contact with other elements and damaged.

The first insulating layer510may be disposed on the first electrode210and the second electrode220and may have a first opening OP1that penetrates the first insulating layer510in the subsidiary area SA to expose at least a portion of the first electrode210and a second opening OP2that penetrates the first insulating layer510in the subsidiary area SA to expose at least a portion of the second electrode220.

The first opening OP1exposes a portion of the upper surface of the first electrode210in the subsidiary area SA, and the second opening OP2may expose a portion of the upper surface of the second electrode220in the subsidiary area SA. The first and second electrodes210and220may be electrically connected to the first and second contact electrodes710and720, to be described later, through the first opening OP1and the second opening OP2in the subsidiary area SA, respectively.

The second bank600may be disposed on the first insulating layer510. The second bank600may be disposed in a lattice pattern having portions extended in the first direction DR1and the second direction DR2when viewed from the top.

As described above, the second bank600may be disposed across the boundary of the sub-pixels SPX to distinguish between neighboring sub-pixels SPX and may distinguish the emission area EMA from the subsidiary area SA. In addition, the second bank600has a height greater than that of the first bank400to distinguish between the areas. Accordingly, during an inkjet printing process for depositing the light-emitting diodes ED in the process of fabricating the display device10, the ink in which the plurality of light-emitting diodes ED is dispersed may be prevented or substantially prevented from being mixed into the adjacent sub-pixel SPX, and thus, the ink can be ejected (e.g., printed or deposited) into the emission area EMA.

The light-emitting diodes ED may be disposed on the first insulating layer510. The light-emitting diodes ED may be spaced apart from one another along the second direction DR2in which the first and second electrodes210and220are extended and may be aligned substantially parallel to one another.

The light-emitting diodes ED may be disposed between the first sub-bank410and the second sub-bank420. A first end of the light-emitting diode ED may be spaced apart from and face the first area410A of the first sub-bank410, and a second end of the light-emitting diode ED may be spaced apart from and face the first area420A of the second sub-bank420. For example, the outer surfaces of the first sub-bank410and the second sub-bank420spaced apart from and facing the both ends of the light-emitting diode ED, respectively, may have concave curved shapes.

The light-emitting diode ED may be disposed on the first insulating layer510such that both ends thereof are placed on the first electrode210and the second electrode220, respectively. The first electrode210and the second electrode220may at least partially overlap with the both ends of the light-emitting diode ED in the third direction DR3, respectively. The first electrode210may overlap the first end of the light-emitting diode ED in the third direction DR3, and the second electrode220may overlap the second end of the light-emitting diode ED in the third direction DR3. At least one of the first electrode210and the second electrode220may be disposed under the light-emitting diode ED to cover the active layer33of the light-emitting diode ED (see, e.g.,FIG.6).

The light-emitting diode ED may include semiconductor layers doped to have different conductivity types. The light-emitting diode ED may include multiple semiconductor layers and may be aligned so that its first end is directed in a particular orientation depending on the direction of an electric field generated between (or over) the first electrode210and the second electrode220. In addition, the light-emitting diode ED may include the active layer33to emit light of a particular wavelength range.

A second insulating layer520may be partially disposed on the light-emitting diode ED. The second insulating layer520may be disposed to partially surround (e.g., to extend around) the outer surface of the light-emitting diode ED so that the both ends of the light-emitting diode ED are not covered (or are exposed). The portion of the second insulating layer520which is disposed on the light-emitting diode ED may be extended in the first direction DR1on the first insulating layer510when viewed from the top, thereby forming a linear or island-like pattern in each of the sub-pixels SPX. The second insulating layer520may protect the light-emitting diode ED and may fix the light-emitting diode ED during the process of fabricating the display device10.

The material forming the second insulating layer520may be disposed between the first electrode210and the second electrode220, and the recessed empty space between the first insulating layer510and the light-emitting diode ED, may be filled with the material of the second insulating layer520.

The first contact electrode710may be disposed on the second insulating layer520. The first contact electrode710may be disposed on the first electrode210. The first contact electrode710may contact the first end of the light-emitting diode ED exposed by the second insulating layer520and the first electrode210. The first contact electrode710may contact the first electrode210exposed by the first opening OP1formed with the sidewalls of the first insulating layer510in the subsidiary area SA and may contact the first end of the light-emitting diode ED exposed by the second insulating layer520in the emission area EMA. The first contact electrode710may electrically connect the first end of the light-emitting diode ED with the first electrode210.

The third insulating layer530may be disposed on the first contact electrode710. The third insulating layer530may be disposed to completely cover the first contact electrode710and may be disposed to expose the second end of the light-emitting diode ED so that the light-emitting diode ED contacts the second contact electrode720together with the second insulating layer520. The third insulating layer530may electrically insulate the first contact electrode710from the second contact electrode720. In addition, the third insulating layer530may form the second opening OP2exposing the second electrode220together with the first insulating layer510in the subsidiary area SA.

The second contact electrode720may be disposed on the third insulating layer530. The second contact electrode720may be disposed on the second electrode220. The second contact electrode720may contact the second end of the light-emitting diode ED exposed by the second and third insulating layers520and530and the second electrode220. The second contact electrode720may contact the second electrode220exposed by the second opening OP2formed with the sidewalls of the first and third insulating layers510and530in the subsidiary area SA and may contact the second end of the light-emitting diode ED exposed by the second and third insulating layers520and530in the emission area EMA. The second contact electrode720may electrically connect the second ends of the light-emitting diodes ED with the second electrode220.

The first and second contact electrodes710and720may include a conductive material. For example, the first and second contact electrodes710and720may include ITO, IZO, ITZO, aluminum (Al), etc. For example, the first and second contact electrodes710and720may include a transparent conductive material. Because the first and second contact electrodes710and720include a transparent conductive material, light emitted through the both ends of the light-emitting diode ED may transmit through the first and second contact electrodes710and720to proceed toward the first and second electrodes210and220.

The fourth insulating layer540may be disposed on the second contact electrode720. The fourth insulating layer540may be disposed entirely on the substrate SUB to protect the elements disposed thereon against the external environment.

FIG.6is a view showing a light-emitting element according to an embodiment of the present disclosure.

Referring toFIG.6, the light-emitting diode ED is a particulate element and may have a rod-like or cylindrical shape with a certain (or predetermined) aspect ratio. The length of the light-emitting diode ED may be larger than the diameter of the light-emitting diode ED, and the aspect ratio may range from, but is not limited to, about 6:5 to about 100:1.

The light-emitting diode ED may have a size of a nanometer scale (from 1 nm to 1 μm) to a micrometer scale (from 1 μm to 1 mm). According to an embodiment of the present disclosure, both the diameter and length of the light-emitting diode ED may have nanometer scales or micrometer scales. In some other embodiments, the diameter of the light-emitting diode ED may have a nanometer scale, while the length of the light-emitting diode ED may have a micrometer scale. In some embodiments, the diameter and/or length of some of the light-emitting diodes ED may have nanometer scales, while the diameter and/or length of some others of the light-emitting diodes ED have micrometer scales.

According to an embodiment of the present disclosure, the light-emitting diode ED may be an inorganic light-emitting diode. The inorganic light-emitting diode may include a plurality of semiconductor layers. For example, the inorganic light-emitting diode may include a first conductivity type (e.g., n-type) semiconductor layer, a second conductivity type (e.g., p-type) semiconductor layer, and an active semiconductor layer interposed therebetween. The active semiconductor layer may receive holes and electrons from the first conductivity-type semiconductor layer and the second conductivity-type semiconductor layer, respectively, and the holes and electrons reaching the active semiconductor layer may be combined to emit light.

According to an embodiment of the present disclosure, the above-described semiconductor layers may be sequentially stacked along one direction X, which is a longitudinal direction of the light-emitting diode ED. The light-emitting diode ED may include a first semiconductor layer31, an active layer33, and a second semiconductor layer32sequentially stacked in the direction X, as shown in, for example,FIG.6. The first semiconductor layer31, the active layer33, and the second semiconductor layer32may be a first conductivity type semiconductor layer, an active semiconductor layer, and a second conductivity type semiconductor layer described above, respectively.

The first semiconductor layer31may be doped with a first conductivity type dopant. The first conductivity type dopant may be Si, Ge, Sn, etc. According to an embodiment of the present disclosure, the first semiconductor layer31may be n-GaN doped with n-type Si. The first semiconductor layer31may occupy most of the volume of the light-emitting diode ED.

The second semiconductor layer32may be spaced apart from the first semiconductor layers31with the active layer33therebetween. The second semiconductor layer32may be doped with a second conductivity-type dopant, such as Mg, Zn, Ca, Se, and Ba. According to an embodiment of the present disclosure, the second semiconductor layer32may be p-GaN doped with p-type Mg.

The active layer33may include a material having a single or multiple quantum well structure. As described above, the active layer33may emit light as electron-hole pairs are combined therein in response to an electrical signal applied through the first semiconductor layer31and the second semiconductor layer32.

In some embodiments, the active layer33may have a structure in which a semiconductor material having a large band gap energy and a semiconductor material having a small band gap energy are alternately stacked on one another, and the active layer33may include other Group III to Group V semiconductor materials depending on the wavelength range of the emitted light.

The light emitted from the active layer33may exit not only through the both end surfaces in the longitudinal direction of the light-emitting diode ED but also through the outer peripheral surface (e.g., outer surface or side surface) of the light-emitting diode ED. For example, the direction in which the light emitted from the active layer33propagates is not limited to one direction.

The light-emitting diode ED may further include an element electrode layer37disposed on the second semiconductor layer32. The element electrode layer37may contact the second semiconductor layer32. The element electrode layer37may be an ohmic contact electrode but is not limited to it. It may be, for example, a Schottky contact electrode.

When the both ends of the light-emitting diode ED are electrically connected to the contact electrodes710and720through which electric signals are applied to the first and second semiconductor layers31and32, the element electrode layer37may be disposed between the second semiconductor layer32and the corresponding contact electrode to reduce the resistance therebetween. The element electrode layer37may include at least one of aluminum (Al), titanium (Ti), indium (In), gold (Au), silver (Ag), indium tin oxide (ITO), indium zinc oxide (IZO), and indium tin-zinc oxide (ITZO). The element electrode layer37may include a semiconductor material doped with n-type or p-type impurities.

The light-emitting diode ED may further include an insulating film38surrounding (e.g., extending around) the outer peripheral surfaces of the first semiconductor layer31, the second semiconductor layer32, the active layer33, and/or the element electrode layer37. The insulating film38may be disposed to surround at least the outer surface of the active layer33and may be extended in the direction X in which the light-emitting diode ED is extended. The insulating film38may protect the above-described elements. The insulating film38may include (or may be made of) materials having insulating properties and may prevent or substantially prevent an electrical short-circuit from occurring when the active layer33contacts an electrode through which an electric signal is transmitted to the light-emitting diode ED. In addition, because the insulating film38protects the active layer33and the outer peripheral surfaces of the first and second semiconductor layers31and32, a decrease in luminous efficiency may be mitigated or prevented.

According to an embodiment of the present disclosure, the active layer33of the light-emitting diode ED may be shifted from the central area of the light-emitting diode ED in the direction X in which the light-emitting diode ED is extended so that the active layer33is located closer to one side of the light-emitting diode ED in the direction X. As described above, the first semiconductor layer31may be formed to occupy most of the light-emitting diode ED. For example, the length h2of the first semiconductor layer31in the direction X may be greater than the length h3of the second semiconductor layer32in the direction X, the length h4of the active layer33in the direction X, and the length h5of the element electrode layer37in the direction X. Moreover, the length h2of the first semiconductor layer31in the direction X may be greater than the sum of the length h3of the second semiconductor layer32in the direction X and the length h5of the element electrode layer37in the direction X. In some embodiments, the length h2of the first semiconductor layer31in the direction X may be greater than the sum h6of the length h3of the second semiconductor layer32in the direction X, the length h4of the active layer33in the direction X, and the length h5of the element electrode layer37in the direction X.

The length h2of the first semiconductor layer31in the direction X may be greater than one-half of the length h1of the light-emitting diode ED in the direction X. Accordingly, the active layer33, which is disposed between the first semiconductor layer31and the second semiconductor layer32, may be shifted from the center of the light-emitting diode ED in the direction X so that it is located closer to the one side in direction X (e.g., the side at where the second semiconductor layer32is disposed). Because the active layer33is located closer to the one side in the longitudinal direction of the light-emitting diode ED, the intensity of light emitted from the active layer33through the both end surfaces and the outer peripheral surface of the light-emitting diode ED may be greater at the end nearer to the active layer33than at the opposite end of the light-emitting diode ED. In addition, the intensity of light emitted through the outer circumferential surface of the light-emitting diode ED may be greater at the first end of the light-emitting disposed ED, to which the active layer33is closer, than at the second end thereof.

FIG.7is an enlarged, cross-sectional view showing the area A ofFIG.4, andFIG.8is an enlarged cross-sectional view of a part ofFIG.7.

Referring toFIGS.7and8, as described above, each of the first sub-bank410and the second sub-bank420may have a shape protruding from the via layer165, and at least a part of the shape of each of the first sub-bank410and the second sub-bank420that faces the light-emitting diode ED may have a concave curved shape.

The first areas410A and420A of the first and second sub-banks410and420facing the both ends of the light-emitting diode ED, respectively, may have a concave curved shape in a cross section of the light-emitting diode while the second areas410B and420B of the first and second sub-banks410and420may have a concave curved shape in the cross section of the light-emitting diode. Each of the first and second sub-banks410and420may have a cross-sectional shape having an inclination angle of the outer surface that varies along the third direction DR3. The inclination angle of each of the first and second sub-banks410and420may be measured as the slope of a tangent line on the outer surface thereof. Each of the first areas410A and420A of the first and second sub-banks410and420may have a cross-sectional shape in which the inclination angle of the outer surface (or surface) increases along the third direction DR3. Each of the second areas410B and420B of the first and second sub-banks410and420may have a cross-sectional shape in which the inclination angle of the outer surface (or surface) decreases along the third direction DR3.

The inclination angle of an outer surface410S of the first sub-bank410may vary along the third direction DR3. For example, the inclination angle of an outer surface410A_S of the first area410A of the first sub-bank410may increase along the third direction DR3. For example, the first to third inclination angles θ1a, θ1b, and θ1cof the outer surface410A_S of the first area410A of the first sub-bank410may be different from one another. In addition, the first to third inclination angles θ1a, θ1b, and θ1cof the outer surface410A_S of the first area410A of the first sub-bank410sequentially measured in the third direction DR3may increase along the third direction DR3, as shown inFIG.8.

The inclination angle of an outer surface410B_S of the second area410B of the first sub-bank410may decrease along the third direction DR3. For example, the first to third inclination angles θ2a, θ2b, and θ2cof the outer surface410B_S of the second area410B of the first sub-bank410may be different from one another. In addition, the first to third inclination angles θ2a, θ2b, and θ2cof the outer surface410B_S of the second area410B of the first sub-bank410sequentially measured in the third direction DR3may decrease along the third direction DR3, as shown inFIG.8.

It is to be understood that the foregoing description can be equally applied to the first and second areas420A and420B of the second sub-bank420.

As described above, the first electrode210and the second electrode220may be disposed on the first and second sub-banks410and420, respectively, and the via layer165. The first and second electrodes210and220may be disposed on the first and second sub-banks410and420, respectively, and the via layer165, and may have the cross-sectional shape of the surface conforming to the cross-sectional shape of the surface of the first and second sub-banks410and420or the via layer165disposed thereunder. For example, the cross-sectional shapes of the surfaces of the first electrode210and the second electrode220may conform to the shapes of the outer surfaces (or surfaces) of the first and second sub-banks410and420, respectively, and/or the via layer165disposed thereunder.

The first electrode210may have a first section210A disposed on the first area410A of the first sub-bank410, a second section210B disposed on the second area410B of the first sub-bank410, and a third section210C disposed on the via layer165between the first sub-bank410and the second sub-bank420.

The first section210A of the first electrode210may overlap the first area410A of the first sub-bank410in the third direction DR3. The cross-sectional shape of the surface of the first section210A of the first electrode210may conform to the shape of the outer surface of the first area410A of the first sub-bank410. The cross-sectional shape of the surface of the first section210A of the first electrode210may have a concave curved shape, similarly to the first area410A of the first sub-bank410.

The second section210B of the first electrode210may overlap the second area410B of the first sub-bank410in the third direction DR3. The cross-sectional shape of the surface of the second section210B of the first electrode210may conform to the shape of the outer surface of the second area410B of the first sub-bank410. The cross-sectional shape of the surface of the second section210B of the first electrode210may have a convex curved shape, similarly to the second area410B of the first sub-bank410.

The third section210C of the first electrode210may be disposed on the via layer165between the first sub-bank410and the second sub-bank420. The cross-sectional shape of the surface of the third section210C of the first electrode210may have a shape corresponding to the shape of the outer surface of the via layer165. For example, the surface of the third section210C of the first electrode210may be flat, similarly to the via layer165.

The inclination angle of an outer surface210S of the first electrode210may vary along the third direction DR3. For example, the inclination angle of an outer surface210A_S of the first section210A of the first electrode210may increase along the third direction DR3. For example, the first to third inclination angles θ3a, θ3b, and θ3cof the outer surface210A_S of the first section210A of the first electrode210may be different from one another. In addition, the first to third inclination angles θ3a, θ3b, and θ3cof the outer surface210A_S of the first section210A of the first electrode210sequentially measured in the third direction DR3may increase along the third direction DR3, as shown inFIG.8.

The inclination angle of an outer surface210B_S of the second section210B of the first electrode210may decrease along the third direction DR3. For example, the first to third inclination angles θ4a, θ4b, and θ4cof the outer surface210B_S of the second section210B of the first electrode210may be different from one another. In addition, the first to third inclination angles θ4a, θ4b, and θ4cof the outer surface210B_S of the second section210B of the first electrode210sequentially measured in the third direction DR3may decrease along the third direction DR3, as shown inFIG.8.

The direction in which the light-emitting diode ED is extended may be parallel to the upper surface of the substrate SUB. The plurality of semiconductor layers included in the light-emitting diode ED may be sequentially arranged along the direction parallel to the upper surface of the substrate SUB. For example, the first semiconductor layer31, the active layer33, and the second semiconductor layer32of the light-emitting diode ED may be arranged sequentially parallel to the upper surface of the substrate SUB.

Light generated in (and emitted from) the active layer33of the light-emitting diode ED may exit through the both end surfaces of the light-emitting diode ED and the outer peripheral surface of the light-emitting diode ED. Light exiting through the both end surfaces of the light-emitting diode ED may be incident on the first bank400. In such a case, the direction in which the light emitted from the light-emitting diode ED travels (e.g., is reflected to travel or propagate) may be determined based on the shape of the outer surface of the first bank400that faces the light-emitting diode ED. For example, first and second electrodes210and220, acting as reflective layers that reflect light emitted from the light-emitting diode ED toward the display side, are disposed on the first and second sub-banks410and420to reflect (or have) the surface shapes of the elements disposed thereunder, and thus, the direction in which the light emitted from the light-emitting diode ED travels may be determined according to the shape of the outer surface of the first and second sub-banks410and420facing the both ends of the light-emitting diode ED, respectively.

According to this embodiment, the outer surfaces of the first areas410A and420A of the first and second sub-banks410and420facing the both ends of the light-emitting diode ED may have concave curved shapes, respectively. Accordingly, the surfaces of the first and second electrodes210and220disposed on the first areas410A and420A of the first and second sub-banks410and420may have concave curved shapes, respectively. Because the cross-sectional shapes of the surfaces of the first section210A and220A of the first and second electrodes210and220facing the both ends of the light-emitting diode ED are concave curved shapes, the incident angle of the light emitted from the light-emitting diode ED to be incident on the first sections210A and220A of the first and second electrodes210and220may decrease compared to the incident angle of a convex curved shape. Accordingly, the amount of light emitted from the light-emitting diode ED and directed toward the display side is increased and may be more efficiently concentrated. As a result, luminous efficiency of each sub-pixel SPX can be improved.

A height hb of the first area410A of the first sub-bank410may be smaller than a height ha of the first sub-bank410. In addition, the height hb of the first area410A of the first sub-bank410may be greater than a height he from the upper surface of the via layer165to the upper surface of the light-emitting diode ED in a cross section. Because the height hb of the first area410A of the first sub-bank410is greater than the height he from the upper surface of the via layer165to the upper surface of the light-emitting diodes ED in the cross section, even when light emitted through both end surfaces of the light-emitting diode ED has a certain directivity angle, the light can be incident on the first area410A of the first sub-bank410. Accordingly, the efficiency of collecting light emitted from the light-emitting diode ED using the first section210A of the first electrode210having the concave curved shape can be improved.

As described above, the first electrode210and the second electrode220may protrude from (or extend beyond) the first sub-bank410and the second sub-bank420, respectively, to the area between the first sub-bank410and the second sub-bank420. The width d1of the portion of the first electrode210extended from the first sub-bank410into the area between the first sub-bank410and the second sub-bank420may be greater than the width d2of the portion of the second electrode220extended from the second sub-bank420into the area between the first sub-bank410and the second sub-bank420. That is to say, the width d1of the portion of the first electrode210extended from the first sub-bank410into the area between the first sub-bank410and the second sub-bank420may be greater than the width d2of the portion of the second electrode220extended from the second sub-bank420into the area between the first sub-bank410and the second sub-bank420.

The first electrode210may overlap the first end of the light-emitting diode ED in the third direction DR3under the light-emitting diode ED, and the second electrode220may overlap the second end of the light-emitting diode ED in the third direction DR3under the light-emitting diode ED. The width w1at where the first electrode210overlaps the first end of the light-emitting diode ED in the third direction DR3may be larger than the width w2at where the second electrode220overlaps the second end of the light-emitting diode ED in the third direction DR3. For example, the light-emitting diode ED may be disposed at the center of the area between the first sub-bank410and the second sub-bank420. Accordingly, a third horizontal distance d3between the first sub-bank410and the first end of the light-emitting diode ED may be equal to a fourth horizontal distance d4between the second sub-bank420and the second end of the light-emitting diode ED. Although the light-emitting diode ED is disposed generally at the center between the first sub-bank410and the second sub-bank420, the first electrode210and the second electrode220are formed such that the width d1of the first electrode210at where it protrudes from the first sub-bank410into the area between the first sub-bank410and the second sub-bank420is greater than the width d2of the second electrode220at where it protrudes from the second sub-bank420into the area between the first sub-bank410and the second sub-bank420. Accordingly, the width w1at where the first electrode210overlaps the first end of the light-emitting diode ED in the third direction DR3may be greater than the width w2at where the second electrode220overlaps the second end of the light-emitting diode ED in the third direction DR3.

In addition, the width w1at where the first electrode210overlaps the first end of the light-emitting diode ED in the third direction DR3may be larger than a distance h6from the first end of the light-emitting diode ED to the first semiconductor layer31. Therefore, the width w1at where the first electrode210overlaps the first end of the light-emitting diode ED in the third direction DR3is greater than the width w2at where the second electrode220overlaps the second end of the light-emitting diode ED in the third direction DR3and the distance h6from the first end of the light-emitting diode ED to the first semiconductor layer31; thus, the first electrode210may cover (e.g., may extend entirely beneath) the active layer33of the light-emitting diode ED under the light-emitting diode ED. Accordingly, light emitted from the active layer33of the light-emitting diodes ED and traveling downwardly can be reflected by the first electrode210to improve light emission efficiency.

FIG.9is a cross-sectional view illustrating directions in which light emitted from a light-emitting diode ED of a display device according to an embodiment travel (or propagate).FIG.10is an enlarged, cross-sectional view showing the area B ofFIG.9.

Referring toFIGS.9and10, paths in which the light emitted from the light-emitting diode ED transmit a plurality of insulating layers and/or the contact electrodes710and720and then are reflected by the first electrode210and the second electrode220will be described in detail.

Referring toFIGS.9and10, first light L1generated in the active layer33of the light-emitting diode ED and exiting through both end surfaces may be incident on the first and second areas410A and420A of the first and second sub-banks410and420. For example, first light L1aexiting through one end surface of the light-emitting diode ED may be incident on the first area410A of the first sub-bank410, and first light L1bexiting through the opposite end surface of the light-emitting diode ED may be incident on the first area420A of the second sub-bank420. The first light L1aincident on the first area410A of the first sub-bank410and the first light L1bincident on the first area420A of the second sub-bank420may transmit (e.g., may transmit through) the transparent insulating layers510and530and the first and second contact electrodes710and720to be incident on the surfaces of the first and second electrodes210and220. The surfaces of the first sections210A and220A of the first and second electrodes210and220disposed on the first areas410A and420A of the first and second sub-banks410and420have concave curved surface shapes, and thus, the first incident angle θI1of the first light L1may be smaller than the convex curved shape. Accordingly, because the first reflection angle θR1of the reflected light LR1has the angle equal to the first incident angle θI1of the first light L1, the efficiency of collecting the reflected light LR1can be improved.

In addition, most of the light generated from the active layer33of the light-emitting diode ED and exiting through the outer circumferential surface may be closer to the active layer33. Accordingly, from among the light exiting through the outer circumferential surface of the light-emitting diode ED, the second light L2traveling downwardly may be reflected by the first electrode210disposed thereunder. The second light L2traveling downwardly from the outer circumferential surface of the light-emitting diode ED may be incident on the third section210C of the first electrode210with a second incident angle θI2and may be reflected at the surface210C_S of the third section210C of the first electrode210with a second reflection angle θR2to be incident on the first section210A of the first electrode210with a third incident angle θI3. Because the reflected light LR2incident with the third incident angle θI3has the angle equal to the third incident angle θI3of the reflected light LR2, it is reflected and the efficiency of collecting the reflected light LR3of the second light L2can be improved.

FIG.11is an enlarged, cross-sectional view showing the area A ofFIG.4according to another embodiment.

The embodiment shown inFIG.11is different from the embodiment shown inFIG.7in that the third insulating layer530is omitted.

For example, the first and second contact electrodes710and720_1may be disposed directly on the second insulating layer520. The first contact electrode710and the second contact electrode720_1may be spaced apart from each other on the second insulating layer520to expose a portion of the second insulating layer520. The exposed portion of the second insulating layer520between the first and second contact electrodes710and720_1may contact the fourth insulating layer540.

According to this embodiment, even though the third insulating layer530is omitted, the second insulating layer520includes an insulating material to fix the light-emitting diode ED. The first contact electrode710and the second contact electrode720_1may be patterned via a single mask process and formed together (e.g., formed concurrently or simultaneously). Therefore, no additional mask process is required to form the first contact electrode710and the second contact electrodes720_1, and thus, the efficiency of the process of fabricating the display device10can be improved. This embodiment is identical to the embodiment ofFIG.7except that the third insulating layer530is omitted; and, therefore, redundant descriptions will be omitted.

FIGS.12to19are cross-sectional views showing processing steps of fabricating a display device according to an embodiment of the present disclosure.

Initially, referring toFIG.12, a substrate SUB is prepared, and a circuit layer CCL is formed on the substrate SUB. The circuit layer CCL may include a buffer layer161, a bottom metal layer110, first to third conductive layer, a semiconductor layer, a gate insulator162, first and second interlayer dielectric layers163and164, and a via layer165. First and second electrode contact openings CT1and CT2may be formed through the via layer165to expose the first conductive pattern CDP and the second voltage line VL2as discussed above with respect to, for example,FIG.4. The semiconductor layer, the plurality of conductive layers, and the insulating layers may be formed via typical processes well known in the art. Therefore, a detailed description thereof will be omitted.

Subsequently, referring toFIG.13, a material layer400′ for a first bank is formed on the via layer165. The material layer400′ for the first bank may be applied entirely on the substrate SUB.

Subsequently, the material layer400′ is exposed to light and developed using a light mask MK so that the first bank400including the patterned first and second sub-banks410and420can be formed.

Initially, the light mask MK is prepared (or arranged) above the substrate SUB.

The light mask MK may include a plurality of regions R1, R2, and R3having different light transmittances. The light mask MK may include a first light-transmitting region R1, a second light-transmitting region R2, and a light-blocking region R3according to the transmittances of light. The transmittance of the light-blocking region R3may be lower than that of each of the first and second light-transmitting regions R1and R2. For example, the light-blocking region R3may block substantially all of the light provided from the outside (e.g., may have a transmittance of approximately 0%), the first light-transmitting region R1may transmit substantially all of the light provided from the outside (e.g., may have a transmittance of approximately 100%), and the second light-transmitting region R2may transmit some of the light provided from the outside (e.g., may have a transmittance of approximately 20% to 30%). It is, however, to be understood that the present disclosure is not limited thereto. The light-blocking region R3may transmit some of the light with a light transmittance significantly lower than that of each of the first and second light-transmitting regions R1and R2.

Subsequently, the light mask MK may be placed above the material layer400′, and an exposure process may be carried out.

The light mask MK may be disposed such that the light-blocking region R3is in line with (e.g., is aligned over) an area where the first bank400is not formed, the second light-transmitting region R2is in line with areas where the first areas410A and420A of the first bank400are formed, and the first light-transmitting region R1is in line with areas where the second areas410B and420B of the first bank400are formed. For example, the area where the material layer400′ for the first bank remains and a concave curved shape is required may be in line with the second light-transmitting region R2, the area where the material layer400′ for the first bank remains but a concave curved shape is not required may be in line with the first light-transmitting region R1, and the area where the material layer400′ for the first bank is to be removed may be in line with the light-blocking region R3.

The light-blocking region R3can block light provided from the outside so that the light does not reach the material layer400′ overlapping the area where the first bank400should not be formed. In addition, the second light-transmitting region R2can allow only some of the light to reach the material layer400′ overlapping the area where the material layer400′ remains and a concave curved shape is to be formed. In addition, the first light-transmitting region R1can allow most of the light to reach the material layer400′ overlapping the area where the material layer400′ remains but a concave curved shape is to be formed. As the chemical characteristics of the material layer400′ change differently depending on whether it is exposed to light or not, it is possible to selectively remove some regions of it while leaving other regions by using a developing solution.

Accordingly, via the exposure process and development, the material layer400′ in line with the light-blocking region R3may be removed, the second areas410A and420B of the first and second sub-bank410and420may be formed at the area in line with the first light-transmitting region R1, and the first areas410A and420B of the first and second sub-bank410and420may be formed at the area in line with the second light-transmitting region R2, as shown inFIG.14.

Subsequently, referring toFIG.15, a first electrode210and a second electrode220may be formed on the first bank400. The patterned first electrode210and second electrode220may be formed via a mask process. For example, a material layer for an electrode layer is deposited entirely on the first bank400(and, in some embodiments, on the via layer165). During the deposition process, the material layer for the electrode layer may be deposited up to the inside of the first and second electrode contact openings CT1and CT2penetrating the via layer165and may be connected to the first conductive pattern CDP and the second voltage line VL2thereunder. Subsequently, after applying a photoresist layer on the material layer for the electrode, a photoresist pattern is formed by exposure and development, and then the material layer for the electrode is etched using the photoresist pattern as an etching mask. Subsequently, the photoresist pattern is removed via a strip process or an ashing process, to form the patterned first electrode210and second electrode220, as shown inFIG.15.

As described above, the first electrode210and the second electrode220may be formed such that the width d1of the portion of the first electrode210extended from the first sub-bank410into the area between the first sub-bank410and the second sub-bank420may be different from the width d2of the portion of the second electrode220extended from the second sub-bank420into the area between the first sub-bank410and the second sub-bank420. For example, the first electrode210and the second electrode220may be formed such that the width d1of the portion of the first electrode210extended from the first sub-bank410into the area between the first sub-bank410and the second sub-bank420may be greater than the width d2of the portion of the second electrode220extended from the second sub-bank420into the area between the first sub-bank410and the second sub-bank420.

Subsequently, as shown inFIG.16, a first insulating layer510is formed on the first and second electrodes210and220, and a second bank600is formed. The first insulating layer510may be disposed to entirely cover the first electrode210and the second electrode220on the substrate SUB and may be partially patterned during a subsequent process to form the first insulating layer510as shown in, for example,FIGS.4and5.

Subsequently, as shown inFIG.17, a light-emitting diode ED is disposed between the first sub-bank410and the second sub-bank420. The light-emitting diode ED may be disposed by using an inkjet process. For example, an ink in which the light-emitting diodes ED are dispersed is ejected into the emission area EMA partitioned by the second bank600, and an alignment signal is applied between the first electrode210and the second electrode220. Then, by using an electric field formed therebetween, the light-emitting diode ED may be aligned such that the both ends thereof are placed on the first electrode210and the second electrode220, respectively.

Subsequently, as shown inFIG.18, a second insulating layer520, a first contact electrode710, and a third insulating layer530are formed on the light-emitting diode ED.

Initially, the second insulating layer520shown inFIG.18may be formed by stacking a second insulating material layer entirely on the substrate SUB on which the light-emitting diodes ED and the first insulating layer510are formed and removing a portion of the second insulating material layer so that the first ends and the second ends of the light-emitting diodes ED are exposed.

Subsequently, a first contact electrode710is formed on the second insulating layer520. In an embodiment, the first contact electrode710may be formed via a mask process. For example, a material layer for the first contact electrode is disposed entirely on the substrate SUB. Subsequently, a photoresist layer is applied onto the material layer for the first contact electrode, and a photoresist pattern is formed by exposure and development. Then, etching is carried out by using the photoresist pattern as an etch mask. The material layer for the first contact electrode may be etched entirely by, but is not limited to, wet etching. Subsequently, the photoresist pattern may be removed via a strip process or an ashing process to form the first contact electrode710as shown in, for example,FIG.18.

Subsequently, a third insulating layer530is formed on the first contact electrode710. The patterned third insulating layer530may be formed by depositing a material layer for the third insulating layer entirely on the substrate SUB and forming an opening for exposing the first insulating layer510and the second end of the light-emitting diode ED on the second electrode220.

Subsequently, as shown inFIG.19, a second contact electrode720is formed on the third insulating layer530. In an embodiment, the second contact electrode720may be formed via a mask process. For example, a material layer for the second contact electrode is disposed entirely on the substrate SUB. Subsequently, a photoresist layer is applied onto the material layer for the second contact electrode, and a photoresist pattern is formed by exposure and development. Then, etching is carried out by using the photoresist pattern as an etch mask. The material layer for the second contact electrode720may be etched entirely by, but is not limited to, wet etching. Subsequently, the photoresist pattern may be removed via a strip process or an ashing process to form the second contact electrode720as shown in, for example,FIG.19.

Subsequently, a fourth insulating layer540is formed entirely on the substrate SUB, thereby fabricating the display device10as shown in, for example,FIG.4.

Hereinafter, other embodiments of the present disclosure will be described. In the following description, the same or similar elements will be denoted by the same or similar reference numerals, and redundant descriptions thereof may be omitted or briefly described. Descriptions will focus on differences from the above embodiment.

FIG.20is a cross-sectional view taken along the line Q2-Q2′ ofFIG.3of another embodiment.

The embodiment shown inFIG.20is different from the embodiment shown inFIG.7in that the height hb of the first areas410A and420A of the first and second sub-banks410and420is equal to the maximum height ha of the first and second sub-banks410and420.

According to this embodiment, the height hb of the first areas410A and420A of the first and second sub-banks410and420is equal to the maximum height ha of the first and second sub-banks410and420in the display device10, and thus, the amount of the light that is emitted from the light-emitting diode ED and is incident on the first areas410A and420A of the first and second sub-banks410and420may increase. For example, the amount of light that is emitted from the light-emitting diode ED and leaks through regions other than the first areas410A and420A of the first and second sub-banks410and420can be reduced. As a result, the amount of light that is emitted from the light-emitting diode ED and is incident on the first areas410A and420A of the first and second sub-banks410and420is increased so that the efficiency of collecting the light emitted from the light-emitting diode ED can be further improved.

FIG.21is a cross-sectional view taken along the line Q2-Q2′ ofFIG.3according to another embodiment.

The embodiment shown inFIG.21is different from the embodiment shown inFIG.7in that one of the outer surfaces of a first bank400_2that faces a second bank600may also include a concave curved shape.

For example, a first sub-bank410_1may include a first area410A1facing a first end of the light-emitting diode ED and having a concave curved shape, a second area410A2facing the second bank600and having a concave curved shape, and a third area410B disposed between the first area410A1and the second area410A2. The third area410B of the first sub-bank410_1may have a convex curved shape or a flat surface.

Similarly, a second sub-bank420_1may include a first area420A1facing a second end of the light-emitting diode ED and having a concave curved shape, a second area420A2facing the second bank600and having a concave curved shape, and a third area420B disposed between the first area420A1and the second area420A2. The third area420B of the second sub-bank420_1may have a convex curved shape or a flat surface.

In concluding the detailed description, those skilled in the art will appreciate that many variations and modifications can be made to the embodiments described herein without substantially departing from the teachings of the present disclosure. Therefore, the described embodiments are used in a generic and descriptive sense only and not for purposes of limitation.