Display device

A display device a includes: a transistor disposed on a first substrate; an insulating layer disposed on the transistor; a first electrode disposed on the insulating layer; a partition disposed on the first electrode and the insulating layer, an opening is defined through the partition; a light-emitting element layer disposed in the opening; and a second electrode disposed on the light-emitting element layer and the partition. The insulating layer includes a first region and a third region having different heights from each other and a second region having an inclined surface connecting the first region and the third region, the first region has a lower height than the third region, and the first electrode overlaps the first region in a direction perpendicular to the first substrate.

This application claims priority to Korean Patent Application No. 10-2019-0123992, filed on Oct. 7, 2019, and all the benefits accruing therefrom under 35 U.S.C. § 119, the content of which in its entirety is herein incorporated by reference.

BACKGROUND

The disclosure relates to a display device, and more particularly, to a display device with improved luminous efficiency.

(b) Description of the Related Art

Among display devices, which display images, a light emitting diode display has been in the spotlight.

The light emitting diode display has a self-luminance characteristic and may not include a separate light source, unlike a liquid crystal display (“LCD”) device, and thus may have reduced thickness and weight. Further, the light emitting diode display may have desired quality characteristics such as low power consumption, high luminance, and a high reaction speed.

Generally, the light emitting diode display includes a substrate, a plurality of thin film transistors disposed on the substrate, a plurality of insulating layers disposed between elements the thin film transistors, and a light emitting element connected to the thin film transistor.

Recently, display devices including a color conversion layer have been proposed to realize high efficiency display devices.

SUMMARY

Exemplary embodiments are to provide a display device with improved light emission efficiency by increasing reflectance and reducing absorption of light emitted from the light-emitting element.

According to an embodiment of the invention, a display device includes: a transistor disposed on a first substrate; an insulating layer disposed on the transistor; a first electrode disposed on the insulating layer; a partition disposed on the first electrode and the insulating layer, where an opening is defined through the partition; a light-emitting element layer disposed in the opening; and a second electrode disposed on the light-emitting element layer and the partition, wherein the insulating layer includes a first region and a third region having different heights from each other and a second region having an inclined surface connecting the first region and the third region, the first region has a lower height than the third region, and the first electrode overlaps the first region in a direction perpendicular to the first substrate.

In an embodiment, the partition may include an inorganic material including silicon.

In an embodiment, the partition may further include carbon.

In an embodiment, the partition may include at least one material selected from SiOx, SiNx, SiON, and siloxane.

In an embodiment, the thickness of the partition may be in a range of about 1000 angstrom (Å) to about 3000 Å.

In an embodiment, a refractive index difference of the partition and the light-emitting element layer may be less than about 50% of a refractive index of the partition.

In an embodiment, the partition may have an inclined surface overlapping the second region.

In an embodiment, the first electrode in the second region may be disposed between the insulating layer and the partition.

In an embodiment, a lowermost surface of the second electrode may be closer to the first substrate than an uppermost surface of the partition.

In an embodiment, a lower surface of the second electrode may be disposed at a same height as an upper surface of the opening of the partition.

In an embodiment, an uppermost surface of the partition may be disposed closer to the first substrate than a lowermost surface of the second electrode.

In an embodiment, a second substrate overlapping the first substrate, and a color conversion layer disposed on the second substrate may be further included, and the color conversion layer may be disposed overlapping the light-emitting element layer in the direction perpendicular to the first substrate.

In an embodiment, the light-emitting element layer may emit a blue light.

In an embodiment, the partition may include an organic material.

According to another embodiment of the invention, a display device includes: a transistor disposed on a substrate; an insulating layer disposed on the transistor; a first electrode disposed on the insulating layer; a reflection member disposed between the insulating layer and the first electrode; a partition disposed on the first electrode and the insulating layer, where an opening is defined through the partition; a light-emitting element layer disposed in the opening; and a second electrode disposed on the light-emitting element layer and the partition, where a side surface of the reflection member adjacent to the opening includes an inclined surface.

In an embodiment, the reflection member may include a metal.

In an embodiment, the reflection member may have a multilayer structure of one among Ti/Al/Ti, Mo/Al/Mo, and Ti/Cu.

In an embodiment, the first electrode may be disposed over the reflection member.

In an embodiment, the partition may be disposed on the reflection member, and the first electrode may be disposed between the reflection member and the partition on the inclined surface of the reflection member.

In an embodiment, a lowermost surface of the second electrode may be closer to the first substrate than an uppermost surface of the partition.

In an embodiment, a lower surface of the second electrode may be disposed at a same height as an upper surface of the opening of the partition.

In an embodiment, an uppermost surface of the partition may be closer to the first substrate than a lowermost surface of the second electrode.

According to another embodiment of the invention, a display device includes: a transistor disposed on a substrate; an insulating layer disposed on the transistor; a first electrode disposed on the insulating layer; a reflection member disposed on the first electrode; a partition disposed on the first electrode, the reflection member and the insulating layer, where an opening is defined through the partition; a light-emitting element layer disposed in the opening; and a second electrode disposed on the light-emitting element layer and the partition, where a side surface of the reflection member adjacent to the opening includes an inclined surface.

In an embodiment, the reflection member may include a metal.

In an embodiment, the reflection member may have a multilayer structure of one among Ti/Al/Ti, Mo/Al/Mo, and Ti/Cu.

In an embodiment, a partial region of the reflection member may not overlap the first electrode in a direction perpendicular to the first substrate.

In an embodiment, one side surface of the reflection member and one side surface of the first electrode may be aligned with each other.

In an embodiment, a lowermost surface of the second electrode may be closer to the first substrate than an uppermost surface of the partition.

In an embodiment, a lower surface of the second electrode may be disposed at the same height as an upper surface of the opening of the partition.

In an embodiment, an uppermost surface of the partition may be disposed closer to the first substrate than a lowermost surface of the second electrode.

In an embodiment, the partition may be disposed on the reflection member.

According to embodiments of the invention, a display device with improved light emission efficiency by increasing reflectance of light emitted from the light-emitting element and reducing light absorption is provided.

DETAILED DESCRIPTION

In order to clearly describe the invention, portions that are not connected with the description will be omitted. Like reference numerals designate like elements throughout the specification.

In addition, the size and thickness of each configuration shown in the drawings are arbitrarily shown for understanding and ease of description, but the invention is not limited thereto. In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. In the drawings, for better understanding and ease of description, the thicknesses of some layers and areas are exaggerated.

Further, in the specification, the phrase “in a plan view” means when an object portion is viewed from above, and the phrase “in a cross-section” means when a cross-section taken by vertically cutting an object portion is viewed from the side.

Hereinafter, a display device according to an exemplary embodiment of the invention will be described in detail with reference to accompanying drawings.

FIG. 1is a view schematically showing a display device according to an exemplary embodiment of the invention.FIG. 1schematically illustrates a portion of an exemplary embodiment of the display device according to the invention for convenience of illustration and description, and an actual cross-sectional structure of the display device may be different from that shown inFIG. 1.

Referring toFIG. 1, an exemplary embodiment of the display device includes a first substrate110, and a transistor TFT and an insulating layer180disposed on the first substrate110.

In such an embodiment, a first electrode191is connected to the transistor TFT through a contact hole185defined or formed in the insulating layer180. Although the transistor TFT is schematically illustrated inFIG. 1, the transistor TFT includes a gate electrode, a semiconductor layer, a source electrode and a drain electrode, and the first electrode191may be connected to the drain electrode of the transistor TFT.

A partition350, in which an opening355is defined, is disposed on the first electrode191. A second electrode270is disposed on the partition350, and a light-emitting element layer370is disposed between the first electrode191and the second electrode270. The first electrode191, the second electrode270, and the light-emitting element layer370are collectively referred to as a light-emitting element LED.

Referring toFIG. 1, the insulating layer180includes a first region A1, a second region A2, and a third region A3.

The first region A1and the third region A3may have different heights from each other. Herein, the term “height” of a region of the insulating layer180means a distance of the region from the first substrate110in a thickness direction of the first substrate110. The first region A1may have a smaller thickness than the third region A3. In such an embodiment, the top of the first region A1is disposed closer to the first substrate110than the top of the third region A3. The second region A2is a part connecting the first region A1and the third region A3, and has an inclined surface.

Referring toFIG. 1, the first electrode191is disposed overlapping the first region A1, the second region A2and the third region A3in the direction perpendicular to the first substrate110. In such an embodiment, an entire portion of the first region A1overlaps the first electrode191.

The partition350overlaps part of the first region A1, the second region A2, and the third region A3. The partition350may have an inclined surface similar to the second region A2.

The light-emitting element layer370is disposed overlapping the first region A1and the second region A2in the direction perpendicular to the first substrate110. The light-emitting element layer370may be disposed along the inclined surface of the second region A2.

The second electrode270is disposed overlapping the first region A1, the second region A2, and the third region A3in the direction perpendicular to the first substrate110.

In such an embodiment, as above-described, the light-emitting element LED is disposed overlapping the first region A1having the smaller thickness of the insulating layer180and the second region A2of the inclined surface, such that the light emitted to the side of the light-emitting element layer370is reflected by the first electrode191, thereby increasing light emission efficiency.

In an exemplary embodiment of the display device, the partition350includes an inorganic material. The partition350may include an inorganic material including silicon. In one exemplary embodiment, for example, the partition350may include at least one material selected from SiOx, SiNx, SiON, and siloxane. Here, x may be 1 to 4. In an exemplary embodiment, the partition350may further include carbon in the inorganic material including silicon (Si).

In a case where the partition350includes an inorganic material including silicon Si, absorption of light at a lower wavelength is relatively low compared to a case where the partition350includes the organic material. In such an embodiment, the partition350includes an inorganic material having a low light absorption, such that the amount that the light reflected from the first electrode191located in the second region A2is absorbed by the partition350is reduced and the transmitted amount is increased, thereby improving the light emission efficiency.

In an exemplary embodiment, a refractive index of the partition350may be similar to that of the light-emitting element layer370. In one exemplary embodiment, for example, a refractive index difference of the partition350and the light-emitting element layer370may be less than about 50% of the refractive index of the partition350. In such an embodiment, as above-described, where the refractive index of the partition350is similar to that of the light-emitting element layer370, the light reflected from the first electrode191may easily exit the interface of the partition350and the light-emitting element layer370. If the refractive index difference between the partition350and the light-emitting element layer370is large, total reflection may occur at the interface. Also, as the refractive index difference is increased, it is harder for light to escape from the partition350.

In a case where the partition350includes the organic material, even if the insulating layer180has a stepped structure as shown inFIG. 1, the light reflected from the inclined surface of the first electrode191is absorbed by the partition350in the process of passing through the partition350, thus the luminous efficiency may not be sufficiently increased. Particularly, when the light-emitting element layer370emits blue light, the absorption at the partition350including the organic material is high. Therefore, in the case of a color conversion display device in which the light-emitting element layer370emits the blue light that is subsequently converted into red light and green light through a color conversion panel, the light emission efficiency increase may not be fully effective by forming the inclined surface of the insulating layer180alone.

In an exemplary embodiment of the display device, the insulating layer180includes the first region A1having a thin thickness, the second region A2of the inclined surface, and the third region A3that is thicker than the first region A1, and the partition350includes the inorganic material. Accordingly, the light emission efficiency may be increased by reflecting the light emitted to the side through the first electrode191positioned in the second region A2, and the light emission efficiency may be increased by reducing the amount of the light absorbed by the partition350.

In an alternative exemplary embodiment, the partition350may include the organic material. In such an embodiment, the partition350may include both organic and inorganic materials, or only the organic material. In an exemplary embodiment, where the partition includes only the organic material, the light emission efficiency may be increased through the inclined surface of the insulating layer180.

FIG. 2is a graph showing a refractive index and an extinction coefficient for polyimide (“PI”) as an organic material, siloxane as an inorganic material, and SiNx.FIG. 2shows the refractive index and the extinction coefficient versus a wavelength (nm) of light.

Referring toFIG. 2, it may be shown that SiNx and siloxane as inorganic materials have lower extinction coefficients compared with polyimide as the organic material. In such an embodiment, it may be confirmed that SiNx has a low extinction coefficient, and the difference of the extinction coefficient with polyimide is significant in a short wavelength region. Therefore, in the light-emitting element emitting the blue light, when the partition is formed of SiNx, the absorption of the reflected light by the partition may be minimized.

Referring back toFIG. 1, the lowermost surface of the second electrode270may be disposed to be lower than the uppermost surface of the partition350. The lower surface of the second electrode270is disposed within the opening355of the partition350. That is, the lowermost surface of the second electrode270is disposed closer to the first substrate110than the uppermost surface of the partition350.

Therefore, most of the light emitted from the light-emitting element layer370between the first electrode191and the second electrode270is reflected at the top and the side inclined surfaces of the first electrode191to maximize the light emission efficiency.

In an exemplary embodiment of the invention, since the partition350includes the inorganic material, the partition350may be formed with a uniform thickness on the first electrode191and the insulating layer180. Although the thickness of the partition350inFIG. 1is slightly different from region to region, this is a modification to clarify the characteristics of the invention, and the actual thickness of the partition350may be uniform.

It is also possible to form the partition350thin, as the partition350includes the inorganic material. In one exemplary embodiment, for example, the thickness of the partition350may be in a range of about 1000 angstrom (Å) to about 3000 Å.

The first electrode191is a reflecting electrode, and may be a multilayer including a transparent conductive oxide layer and a metal layer. In one exemplary embodiment, for example, the first electrode may have a triple layered structure of ITO/Ag/ITO.

FIG. 3is a cross-sectional view showing a display device according to an alternative exemplary embodiment of the invention. The exemplary embodiment of the display device shown inFIG. 3is substantially the same as the exemplary embodiment described above with reference toFIG. 1, except for a height relationship of the partition350and the second electrode270. The same or like elements shown inFIG. 3have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 1, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

Referring toFIG. 3, the upper surface of the partition350and the lower surface of the second electrode270may be disposed at a same height or level from an upper surface of the first substrate110. In such an embodiment, the upper surface of the partition350adjacent to the opening355of the partition350and the lower surface of the second electrode270disposed in the opening355may be disposed on an imaginary horizontal line or plane parallel to the first substrate110. In such an embodiment where the upper surface of the partition350and the lower surface of the second electrode270are disposed at the same height as each other, most of the light emitted from the light-emitting element layer370disposed between the first electrode191and the second electrode270is reflected by the inclined surface and the upper surface of the first electrode191, thereby increasing the light emitting efficiency.

FIG. 4is a cross-sectional view showing a display device according to another alternative exemplary embodiment of the invention. The exemplary embodiment of the display device shown inFIG. 4is substantially the same as the exemplary embodiment described above with reference toFIG. 1, except for the height relationship of the partition350and the second electrode270. The same or like elements shown inFIG. 4have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 1, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

Referring toFIG. 4, the second electrode270is not disposed within the opening355of the partition350. That is, the lowermost surface of the second electrode270in the first region A1is disposed above the uppermost surface of the partition350or farther from the first substrate110than the uppermost surface of partition350. Such a structure may be formed when the partition350including the inorganic material is formed thin and the light-emitting element layer370is formed thick. In such an embodiment shown inFIG. 4, most of the light emitted laterally in the light-emitting element layer370disposed between the first electrode191and the second electrode270is reflected by the inclined surface of the first electrode191, thereby improving the light emission efficiency.

In an exemplary embodiment, as above-described, the display device includes the first region A1and the third region A3in which the insulating layer180has different heights from each other, and the second region A2having the inclined surface connecting the first region A1and the third region A3. The first electrode191is disposed along the inclined surface of the second region A2, and the light emitted from the side of the light-emitting element layer370is reflected from the side of the first electrode191, thereby increasing the luminous efficiency. In such an embodiment, the partition350includes the inorganic material, such that the light emission efficiency may be improved by increasing the transmittance of the light reflected from the first electrode191. In such an embodiment, the partition350may have a refractive index that is similar to that of the light-emitting element layer370, and the light may easily exit the interface of the partition350and the light-emitting element layer370, thereby increasing the light emission efficiency.

Next, a display device according to another alternative exemplary embodiment of the invention will be described.FIG. 5is a cross-sectional view showing a display device according to another alternative exemplary embodiment of the invention. The exemplary embodiment of the display device shown inFIG. 5is substantially the same as the exemplary embodiment of the display device described above with reference toFIG. 1, except for a configuration of the insulating layer180and a reflection member410. The same or like elements shown inFIG. 5have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 1, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

Referring toFIG. 5, in an exemplary embodiment of the display device, the insulating layer180has a substantially constant height or thickness without the first region and the second region having different heights or thickness from each other. In such an embodiment, the insulating layer180may have a flat upper surface. In such an embodiment, the display device includes a reflection member410disposed between the insulating layer180and the first electrode191.

The side surface of the reflection member410may be inclined. The first electrode191may be disposed on the upper surface and the inclined side surface of the reflection member410. In such an embodiment, since the first electrode191has the inclined side surface corresponding to the side surface of the reflection member410, the light emitted to the side surface of the light-emitting element layer370may be reflected by the first electrode191and the reflection member410, thereby increasing the light emission efficiency.

The reflection member410may include a metal. The reflection member410may have a single layer structure or a multi-layer structure. In one exemplary embodiment, for example, the reflection member410may have a triple layered structure of Ti/Al/Ti or Mo/Al/Mo. Alternatively, the reflection member410may have a dual-layered structure of Ti/Cu. However, the material of the reflection member410is not limited to the above material, and any metal having a reflection property may be used without limitation.

In an exemplary embodiment, as shown inFIG. 5, the shape of the reflection member410may be a trapezoid when viewed from a cross-sectional view perpendicular to the first substrate110, but the shape of the reflection member410is not limited thereto. In an exemplary embodiment, the reflection member410is not limited in the shape as long as the side surface of the region adjacent to the opening of the partition350includes an inclined surface. Alternatively, the shape of the reflection member410when viewed from the cross-sectional view perpendicular to the first substrate110may be a triangle or a quadrangle including only one inclined surface.

In such an embodiment, the partition350may include an organic material or an inorganic material. In one exemplary embodiment, for example, the partition350may include an inorganic material including Si. The partition350may include at least one material selected from SiOx, SiNx, SiON, and siloxane. In such an embodiment, the partition350may further include carbon in the inorganic material including silicon.

In a case where the partition350includes the inorganic material including Si, the absorption for the light of the lower wavelength is relatively low compared with a case where the partition350includes the organic material. In an exemplary embodiment where the partition350includes an inorganic material having a low light absorption, the amount that the light reflected from the reflection member410is absorbed to the partition350is reduced, thereby increasing the light emission efficiency.

The refractive index of the partition350may be similar to that of the light-emitting element layer370. In one exemplary embodiment, for example, the difference between the refractive index of the partition350and the light-emitting element layer370may be about 50% or less. In an exemplary embodiment, as above-described, when the refractive index of the partition350is similar to that of the light-emitting element layer370, the light reflected from the reflection member410may easily exit the interface of the partition350and the light-emitting element layer370.

FIG. 6is a cross-sectional view showing a display device according to another alternative exemplary embodiment of the invention. The exemplary embodiment of the display device shown inFIG. 6is substantially the same as the exemplary embodiment described above with reference toFIG. 5, except for a height relationship between the partition350and the second electrode270. The same or like elements shown inFIG. 6have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 5, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

Referring toFIG. 6, in an exemplary embodiment, the upper surface of the partition350and the lower surface of the second electrode270may be disposed at a same height or level from an upper surface of the first substrate110. In such an embodiment, the upper surface of the partition350adjacent to the opening of the partition350and the lower surface of the second electrode270disposed in the opening may be disposed on an imaginary horizontal line or plane parallel to the first substrate110. In such an embodiment where the upper surface of the partition350and the lower surface of the second electrode270are disposed at the same height as each other, most of the light emitted from the light-emitting element layer370disposed between the first electrode191and the second electrode270to the side surface is reflected by the inclined surface of the reflection member410, thereby increasing the light emitting efficiency.

FIG. 7is a cross-sectional view showing a display device according to another alternative exemplary embodiment of the invention. The exemplary embodiment of the display device shown inFIG. 7is substantially the same as the exemplary embodiment described above with reference toFIG. 5, except for the height relationship of the partition350and the second electrode270. The same or like elements shown inFIG. 7have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 5, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

Referring toFIG. 7, in an exemplary embodiment, the second electrode270is not disposed within the opening355of the partition350. In such an embodiment, the lowermost surface of the second electrode270overlapping the opening355of the partition350is disposed above the uppermost surface of the partition350or farther from the first substrate110than the uppermost surface of the partition350. In such an embodiment shown inFIG. 7, most of the light emitted laterally in the light-emitting element layer370disposed between the first electrode191and the second electrode270is reflected by the inclined surface of the reflection member410, thereby improving the light emission efficiency.

FIG. 8is a cross-sectional view showing a display device according to another alternative exemplary embodiment. The exemplary embodiment of the display device shown inFIG. 8is substantially the same as the exemplary embodiment of the display device described above with reference toFIG. 1, except for the configuration of the insulating layer180and the reflection member410. The same or like elements shown inFIG. 8have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 1, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

Referring toFIG. 8, in an exemplary embodiment of the display device, the insulating layer180has a substantially same height or a substantially constant thickness without the first region and the second region having different heights from each other. In such an embodiment, as shown inFIG. 8, the display device includes the reflection member410disposed on the first electrode191.

The side surface of the reflection member410may be inclined. The light emitted to the side surface of the light-emitting element layer370is reflected by the reflection member410, thereby increasing the light emission efficiency.

The reflection member410may include a metal. The reflection member410may have a single layer structure or a multi-layer structure. In one exemplary embodiment, for example, the reflection member410may have a triple layered structure of Ti/Al/Ti or Mo/Al/Mo. Alternatively, the reflection member410may have a dual layered structure of Ti/Cu. However, the material of the reflection member410is not limited to the above material, and any metal with the reflection property may be used without limitation.

Referring toFIG. 8, in an exemplary embodiment, one edge of the reflection member410and one edge of the first electrode191may be disposed on a same plane. In such an embodiment, one side surface of the reflection member410and one side surface of the first electrode191are aligned with each other to form a same inclined surface. This structure may be formed when forming the reflection member410and the first electrode191in a single process using a halftone mask. In such an embodiment, as shown inFIG. 8, the side surface of the reflection member410and the side surface of the first electrode191may be disposed on a same plane.

In an exemplary embodiment, the partition350may include an organic material or an inorganic material. The partition350may include an inorganic material including Si. In one exemplary embodiment, for example, the partition350may include at least one material selected from SiOx, SiNx, SiON, and siloxane. In such an embodiment, the partition350may further include carbon in the inorganic material including silicon.

In a case where the partition350includes the inorganic material including Si, the absorption is relatively low for the light of low wavelengths compared with a case where the partition350includes the organic material. In an exemplary embodiment, the partition350includes an inorganic material having a low light absorption, such that the amount that the light reflected from the reflection member410is absorbed by the partition350is reduced, thereby improving the light emission efficiency.

The refractive index of the partition350may be similar to that of the light-emitting element layer370. In one exemplary embodiment, for example, the refractive index difference between the partition350and the light-emitting element layer370may be about 50% or less. In such an embodiment, as above-described, the refractive index of the partition350is similar to that of the light-emitting element layer370, such that the light reflected from the reflection member410may easily exit the interface of the partition350and the light-emitting element layer370.

FIG. 9is a cross-sectional view showing a display device according to another alternative exemplary embodiment of the invention. The exemplary embodiment of the display device shown inFIG. 9is substantially the same as the exemplary embodiment described above with reference toFIG. 8, except for the height relationship of the partition350and the second electrode270. The same or like elements shown inFIG. 9have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 8, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

Referring toFIG. 9, in an exemplary embodiment, the upper surface of the partition350and the lower surface of the second electrode270may be disposed at a same height or level from an upper surface of the first substrate110. In such an embodiment, the upper surface of the partition350adjacent to the opening of the partition350and the lower surface of the second electrode270disposed at the opening may be disposed on an imaginary horizontal line or plane parallel to the first substrate110. In such an embodiment where the upper surface of the partition350and the lower surface of the second electrode270are disposed at the same height as each other, most of the light emitted from the light-emitting element layer370disposed between the first electrode191and the second electrode270is reflected by the inclined surface of the reflection member410, thereby increasing the light emitting efficiency.

FIG. 10is a cross-sectional view showing a display device according to another alternative exemplary embodiment of the invention. The exemplary embodiment of the display device shown inFIG. 10is substantially the same as the exemplary embodiment described above with reference toFIG. 8, except for the height relationship of the partition350and the second electrode270. The same or like elements shown inFIG. 10have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 8, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

Referring toFIG. 10, in an exemplary embodiment, the second electrode270is not disposed within the opening355of the partition350. In such an embodiment, the lowermost surface of the second electrode270is disposed above the uppermost surface of the partition350or farther from the first substrate110than the uppermost surface of the partition350. In such an embodiment shown inFIG. 10, most of the light emitted laterally in the light-emitting element layer370disposed between the first electrode191and the second electrode270is reflected by the inclined surface of the reflection member410, thereby improving the light emission efficiency.

FIG. 11is a cross-sectional view showing a display device according to another alternative exemplary embodiment of the invention. The exemplary embodiment of the display device shown inFIG. 11is substantially the same as the exemplary embodiment described above with reference toFIG. 8, except for the configuration of the reflection member410and the first electrode191. The same or like elements shown inFIG. 11have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 8, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

Referring toFIG. 11, in an exemplary embodiment of the display device, the side surface edge of the reflection member410and the side surface edge of the first electrode191are not aligned with each other. In such an embodiment, as shown inFIG. 11, the reflection member410includes a region that does not overlap the first electrode191in the direction perpendicular to the first substrate110or the thickness direction of the first substrate110. This structure may be formed when the first electrode191and the reflection member410are formed in separate processes.

In such an embodiment, the reflection member410is substantially the same as that described above with reference toFIG. 8. In such an embodiment, the side surface of the reflection member410may be inclined. The light emitted to the side surface of the light-emitting element layer370may be reflected by the reflection member410to increase the light emission efficiency. The reflection member410may include a metal. The reflection member410may have a single layer structure or a multi-layer structure. In one exemplary embodiment, for example, the reflection member410may have a triple layer structure of Ti/Al/Ti or Mo/Al/Mo. Alternatively, the reflection member410may have a dual layer structure of Ti/Cu. However, the material of the reflection member410is not limited to the above-described material, and any metal with the reflection property may be used without limitation.

In such an embodiment, the partition350is substantially the same as that described above with reference toFIG. 8. In such an embodiment, the partition350may include an organic material or an inorganic material. The partition350may include an inorganic material containing silicon. In one exemplary embodiment, for example, the partition350may include at least one selected from SiOx, SiNx, SiON, and siloxane. In such an embodiment, the partition350may further include carbon in the inorganic material containing silicon.

In a case where the partition350includes the inorganic material including Si, the absorption for the light of lower wavelengths is relatively low compared with a case where the partition350includes the organic materials. In an exemplary embodiment, the partition350includes an inorganic material having a low light absorption, such that the amount that the light reflected from the reflection member410is absorbed to the partition350is reduced, thereby increasing the light emission efficiency.

The refractive index of the partition350may be similar to that of the light-emitting element layer370. In one exemplary embodiment, for example, the refractive index difference between the partition350and the light-emitting element layer370may be about 50% or less. In such an embodiment, as above-described, the refractive index of the partition350is similar to that of the light-emitting element layer370, such that the light reflected from the reflection member410may easily exit the interface of the partition350and the light-emitting element layer370.

FIG. 12is a cross-sectional view showing a display device according to another alternative exemplary embodiment of the invention. Referring toFIG. 12, the display device according to the exemplary embodiment is the same as that the exemplary embodiment ofFIG. 11, except for the height relationship of the partition350and the second electrode270. The same or like elements shown inFIG. 12have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 11, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

Referring toFIG. 12, in an exemplary embodiment, the upper surface of the partition350and the lower surface of the second electrode270may be disposed at a same height or level from an upper surface of the first substrate110. In such an embodiment, the upper surface of the partition350adjacent to the opening of the partition350and the lower surface of the second electrode270disposed at the opening may be positioned on an imaginary horizontal line or plane parallel to the first substrate110. In such an embodiment where the upper surface of the partition350and the lower surface of the second electrode270are disposed at a same height as each other, most of the light emitted from the light-emitting element layer370disposed between the first electrode191and the second electrode270to the side surface is reflected by the inclined surface of the reflection member410, thereby increasing the light emitting efficiency.

FIG. 13is a cross-sectional view showing a display device according to another alternative exemplary embodiment of the invention. The exemplary embodiment of the display device shown inFIG. 13is substantially the same as that of the exemplary embodiment described above with reference toFIG. 11, except for the height relation of the partition350and the second electrode270. The same or like elements shown inFIG. 13have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 11, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

Referring toFIG. 13, in an exemplary embodiment, the second electrode270is not disposed within the opening355of the partition350. In such an embodiment, the lowermost surface of the second electrode270overlapping the opening355is disposed above the uppermost surface of the partition350or farther from the first substrate110than the uppermost surface of partition350. In such an embodiment shown inFIG. 13, most of the light emitted laterally in the light-emitting element layer370disposed between the first electrode191and the second electrode270is reflected by the inclined surface of the reflection member410, thereby improving the light emission efficiency.

Hereinafter, another alternative exemplary embodiment of a display device according to the invention will be described with reference toFIG. 14.

FIG. 14is a cross-sectional view showing a display device according to another alternative exemplary embodiment of the invention. Referring toFIG. 14, an exemplary embodiment of the display device includes a display substrate100and a color conversion substrate300.

The display substrate100includes a first substrate110, a plurality of transistors TFT disposed on the first substrate110, and an insulating layer180. The first electrode191and the partition350are disposed in the insulating layer180, and the first electrode191is disposed in the opening355of the partition350and is connected to the transistor TFT. The second electrode270is disposed on the partition350, and the light-emitting element layer370is disposed between the first electrode191and the second electrode270. The first electrode191, the second electrode270, and the light-emitting element layer370are collectively referred to as a light-emitting element LED.

In such an embodiment, the insulating layer180and the light-emitting element LED is the same as those described above. In such an embodiment, the insulating layer180includes a first region A1, a third region A3disposed higher than the first region A1, and a second region A2having the inclined surface connecting the first region A1and the third region A3.

The first electrode191disposed in the second region A2reflects the light emitted from the light-emitting element layer370to the side surface, thereby increasing the light emission efficiency. In such an embodiment, the partition350includes an inorganic material, and particularly includes an inorganic material including Si such that the light reflected from the first electrode191is effectively transmitted, thereby increasing the light emission efficiency.

InFIG. 14, the display substrate100has the structure corresponding to that shown inFIG. 1, the structure of the display substrate100is not limited thereto, and the display substrate100may be variously modified to have any structure of the exemplary embodiments shown inFIGS. 3 and 4,FIG. 5toFIG. 7,FIG. 8toFIG. 10, orFIG. 11toFIG. 13.

The light-emitting element layer370may emit a blue light. In such an embodiment, the light-emitting element LED emitting the blue light has any structure described above with reference toFIG. 1,FIG. 3,FIG. 4, andFIG. 5toFIG. 13, such that the light emission efficiency of the blue light may be increased as described above.

A light blocking member220is disposed on a second substrate210. The light blocking member220may be disposed overlapping the partition350of the first substrate110.

A plurality of color filters230R,230G, and230B is disposed between the light blocking members220. Each of the color filters230R,230G, and230B is disposed between two adjacent light blocking members220.

A color filter insulating layer250is disposed on the color filter230and the light blocking member220. Color conversion layers330R and330G and a transmission layer330B are disposed on the color filter insulating layer250. In an exemplary embodiment, the color filter insulating layer250is disposed between the color conversion layers330R and330G and the transmission layer330B, and the color filters230R,230G, and230B. The color conversion layers330R and330G and the transmission layer330B may be disposed overlapping the color filters230R,230G, and230B, respectively.

The color conversion layers330R and330G include quantum dots, and convert the incident light into a light of different color. The color conversion layers330R and330G include a green color conversion layer330G and a red color conversion layer330R, which convert the blue light emitted from the light-emitting element layer370into green light and red light, respectively. The transmission layer330B may transmit the blue light as it is.

A planarization layer350may be positioned on the color conversion layers330R and330G and the transmission layer330B.

In an exemplary embodiment, the display device includes the display substrate100and the color conversion substrate300, and the light emitted from the display substrate100is emitted outside through the color filters230R,230G, and230B after passing through the color conversion layers330R and330G or the transmission layer330B of the color conversion substrate300.

In an exemplary embodiment of the display device, the insulating layer180has a same structure as that ofFIG. 1,FIG. 3, andFIG. 4, or further includes the reflection member410as shown inFIG. 5toFIG. 13, thereby having improved light emission efficiency. In such an embodiment, the partition350may include the inorganic material including Si, such that the transmittance of the blue light is high when the light-emitting element layer370emits the blue light, thereby effective improving the light emission efficiency.

Next, the detailed structure of the display device according to an exemplary embodiment of the invention will described with reference toFIGS. 15 and 16. However, this is merely exemplary, and the structure of the invention is not limited thereto.

FIG. 15is a top plan view schematically showing a display panel according to an exemplary embodiment of the invention.FIG. 16is a cross-sectional view taken along line XVI-XVI′ ofFIG. 15,

In an exemplary embodiment, as shown inFIGS. 15 and 16, the display panel may be an active matrix (“AM”) type of light emitting diode display having a two transistor-one capacitor (“2Tr-1Cap”) structure including two thin film transistors T1and T2and a single capacitive element C1in each pixel of the display area, but the invention and the exemplary embodiment are not limited thereto. Alternatively, the light emitting diode display may provide three or more transistors and two or more capacitive elements in one pixel, and separate wiring may be further provided to have a variously modified structure. Here, the pixel is a basic or minimum unit of displaying an image, and the display area displays the image through the plurality of pixels.

Referring toFIG. 15andFIG. 16, an exemplary embodiment of the light emitting diode display includes a switching thin film transistor T1, a driving thin film transistor T2, a capacitive element C1, and a light-emitting element LED, which are respectively formed in a plurality of pixels disposed on the first substrate110. In such an embodiment, a gate line121is disposed along one direction on the first substrate110, and a data line171and a common power source line172crossing and insulated from the gate line121are disposed on the first substrate110. In one exemplary embodiment, for example, each pixel may be defined by boundaries of the gate line121, the data line171, and the common power source line172, but not being limited thereto.

The light-emitting element LED includes a first electrode191, a light-emitting element layer370disposed on the first electrode191, and a second electrode270disposed on the light-emitting element layer370.

In such an embodiment, the first electrode191may be an anode of a hole injection electrode, and the second electrode270may be a cathode of an electron injection electrode. However, the invention is not limited thereto, and alternatively, the first electrode191may be the cathode and the second electrode270may be the anode electrode according to a driving method of a light emitting diode display. In an exemplary embodiment, the first electrode191may be referred to as a pixel electrode and the second electrode270may be referred to as a common electrode.

The light-emitting element layer370may include at least one layer selected from a hole injection layer, a hole transferring layer, an emission layer, an electron transferring layer, and an electron injection layer. In such an embodiment, the emission layer may include an organic emission layer, and light is emitted when an exciton generated by combining an injected hole and an electron falls from an excited state to a ground state. Alternatively, the emission layer may include quantum dots.

The capacitive element C1includes a pair of capacitive plates158cand178cdisposed via an interlayer insulating layer160interposed therebetween. Here, the interlayer insulating layer160includes a dielectric material. Capacitance is determined by a charge accumulated in the capacitive element C1and a voltage between the pair of capacitive plates158cand178c.

The switching thin film transistor T1includes a switching semiconductor layer137, a switching gate electrode122, a switching source electrode176s, and a switching drain electrode177d. The driving thin film transistor T2includes a driving semiconductor layer131, a driving gate electrode124, a driving source electrode173s, and a driving drain electrode175d.

The switching thin film transistor T1is used as a switching element to select a pixel to emit light therefrom. The switching gate electrode122is connected to the gate line121, and the switching source electrode176sis connected to the data line171. The switching drain electrode177dis disposed to be separated from the switching source electrode176sand is connected to one capacitive plate158c.

The driving thin film transistor T2applies driving power to emit the light-emitting element layer370of the light-emitting element LED within the selected pixel to the first electrode191. The driving gate electrode124is connected to the capacitive plate158cconnected to the switching drain electrode177d. The driving source electrode173sand the other capacitive plate178care connected to the common power source line172.

The driving drain electrode175dis connected to the first electrode191through the contact hole185defined or formed in the insulating layer180.

In an exemplary embodiment, as shown inFIGS. 15 and 16, the display panel may be an organic light emitting diode display, but not being limited thereto.

A buffer layer120is disposed on a first substrate110. The first substrate110may include or be made of at least one material selected from a glass, quartz, a ceramic, a plastic, and the like. The buffer layer120may include or be formed of at least one material selected from a silicon nitride (SiNx), a silicon dioxide (SiO2), a silicon oxynitride (SiOxNy) and the like, but not being limited thereto. Here, x and y may be 1 to 5, respectively.

A driving semiconductor layer131is disposed on a buffer layer111. The driving semiconductor layer131may include or be formed of at least one of various semiconductor materials such as a polycrystalline silicon film and an amorphous silicon film. The driving semiconductor layer131may include a source region133, a channel region134, and a drain region135.

A gate insulating layer140including or made of a silicon nitride or a silicon oxide is disposed on the driving semiconductor layer131. The driving gate electrode124and the first capacitive plate158care disposed on the gate insulating layer140. In such an embodiment, the driving gate electrode124is disposed to overlap at least a portion of the driving semiconductor layer131, specifically, the channel region134.

An interlayer insulating layer160covering the driving gate electrode124is disposed on the gate insulating layer140. The interlayer insulating layer160may include or be formed of a silicon nitride or a silicon oxide, as the gate insulating layer140. A first contact hole163and a second contact hole165may be defined through the gate insulating layer140and the interlayer insulating layer160to expose the source region133and the drain region135of the driving semiconductor layer131, respectively.

A driving source electrode173sand a driving drain electrode175d, a data line171, a common power source line172, and a second capacitive plate178care disposed on the interlayer insulating layer160. The driving source electrode173sand the driving drain electrode175dare connected to the source region133and the drain region135of the driving semiconductor layer131through the first contact hole163and the second contact hole165, respectively.

An insulating layer180covering the driving source electrode173sand the driving drain electrode175dis disposed on the interlayer insulating layer160. The insulating layer180may include an organic material such as a polyacryl series or a polyimide series.

The partition350is disposed on the insulating layer180, and an opening355is defined through the partition350by removing a portion thereof. In the opening355, the light-emitting element layer370is disposed overlapping the first electrode191and the second electrode270is disposed to overlap the light-emitting element layer370. The light-emitting element layer370may include at least one selected from the hole injection layer, the hole transferring layer, the emission layer, the electron transferring layer, and the electron injection layer. The second electrode270may be a common electrode. The light-emitting element LED includes the first electrode191, the light-emitting element layer370, and the second electrode270.

In an exemplary embodiment, the partition350may include an organic material or an inorganic material. The partition350may include an inorganic material including silicon. In one exemplary embodiment, for example, the partition350may include at least one material selected from SiOx, SiNx, SiON, and siloxane. In an exemplary embodiment, the partition350may further include carbon in the inorganic material including silicon.

Referring toFIG. 16, the insulating layer180includes the first region A1, the second region A2, and the third region A3. The first region A1has a smaller thickness than the third region A3. In such an embodiment, the top surface of the first region A1is disposed closer to the first substrate110than the top surface of the third region A3. The second region A2has the inclined surface as the part connecting the first region A1and the third region A3. The first electrode191is disposed on the inclined surface of the second region A2, and the first electrode191reflects the light emitted from the light-emitting element layer370to the side surface to increase the light emission efficiency.

In such an embodiment ofFIG. 16may have improved light emission efficiency as the exemplary embodiment ofFIG. 1. In an exemplary embodiment ofFIG. 16, the partition350may include the inorganic material including Si.

FIG. 17is a cross-sectional view showing a display device according an alternative exemplary embodiment. Referring toFIG. 17, an exemplary embodiment of the display device further includes a reflection member410disposed between the insulating layer180and the first electrode191. The exemplary embodiment ofFIG. 17may correspond to the exemplary embodiment ofFIG. 5. The same or like elements shown inFIG. 17have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 5, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

In an exemplary embodiment, referring toFIG. 17, the side surface of the reflection member410may be inclined. The first electrode191may be disposed on the upper surface and the inclined side surface of the reflection member410. Since the first electrode191has the side surface inclined along the side surface of the reflection member410, as inFIG. 16, the light emitted to the side surface of the light-emitting element layer370is reflected by the reflection member410and the first electrode191, thereby increasing the light emission efficiency.

FIG. 18is a cross-sectional view showing a display device according another alternative exemplary embodiment. Referring toFIG. 18, an exemplary embodiment of the display device includes the reflection member410disposed on the first electrode191. The exemplary embodiment ofFIG. 18may correspond to the exemplary embodiment ofFIG. 8. The same or like elements shown inFIG. 18have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 8, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

In an exemplary embodiment, the side surface of the reflection member410may be inclined. The light emitted to the side surface of the light-emitting element layer370is reflected by the reflection member410to increase the light emission efficiency.

Referring toFIG. 18, one edge of the reflection member410and one edge of the first electrode191may be disposed on a same plane. In such an embodiment, one side surface of the reflection member410and one side surface of the first electrode191may form a same inclined surface.

FIG. 19is a cross-sectional view showing a display device according another alternative exemplary embodiment. The display device shown inFIG. 19is substantially the same as the exemplary embodiment ofFIG. 18, except for an alignment of the side surface edge of the reflection member410and the side surface edge of the first electrode191. The same or like elements shown inFIG. 19have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 18, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

Next, a detailed structure of the display device according to another alternative exemplary embodiment of the invention will be described in detail with reference toFIGS. 20 to 25. However, this is merely exemplary, and the structure of the invention is not limited thereto.

FIG. 20is a circuit diagram for a pixel of a display device according to an exemplary embodiment.

Referring toFIG. 20, an exemplary embodiment of the display device may include a plurality of pixels, and one pixel may include a plurality of transistors T1, T2, and T3, a capacitor Cst, and at least one light emitting diode ED. In an exemplary embodiment, as shown inFIG. 20, one pixel includes a single light emitting diode ED, for example, but not being limited thereto.

The plurality of transistors T1, T2, and T3include a first transistor T1, a second transistor T2, and a third transistor T3. The source electrode and the drain electrode, which are described below, may refer to two electrodes disposed on opposite sides of a channel of each of the transistors T1, T2, and T3, and may be interchangeably used.

The gate electrode G1of the first transistor T1is connected to one terminal of the capacitor Cst, the source electrode S1of the first transistor T1is connected to the driving voltage line that transmits the driving voltage ELVDD, and the drain electrode D1of the first transistor T1is connected to the anode of the light emitting diode ED and the other terminal of the capacitor Cst. The first transistor T1receives the data voltage DAT according to the switching operation of the second transistor T2, and supplies the driving current corresponding to the voltage stored in the capacitor Cst to the light emitting diode ED.

The gate electrode G2of the second transistor T2is connected to a first scan line that transmits a first scan signal SC, the source electrode S2of the second transistor T2is connected to a data line that transmits a data voltage DAT or a reference voltage, and the drain electrode D2of the second transistor T2is connected to one terminal of the capacitor Cst and the gate electrode G1of the first transistor T1. The second transistor T2may be turned on in response to the first scan signal SC to transmit the reference voltage or the data voltage DAT to the gate electrode G1of the first transistor T1and one terminal of the capacitor Cst.

The gate electrode G3of the third transistor T3is connected to a scan line that transmits a second scan signal SS, the source electrode S3of the third transistor T3is connected to the other terminal of the capacitor Cst, the drain electrode D1of the first transistor T1, and the anode of the light emitting diode ED, and the drain electrode D3of the third transistor T3is connected to an initialization voltage line that transmits an initialization voltage INIT. The third transistor T3may be turned on in response to the second scan signal SS to transmit the initialization voltage INIT to the anode of the light emitting diode ED and the other terminal of the capacitor Cst, thereby initializing the voltage of the anode of the light emitting diode (LED) ED.

One terminal of the capacitor Cst is connected to the gate electrode G1of the first transistor T1, and the other terminal of the capacitor Cst is connected to the source electrode S3of the third transistor T3and the anode of the light emitting diode ED. The cathode of the light emitting diode ED is connected to a common voltage line transmitting a common voltage ELVSS.

The light emitting diode ED may emit light corresponding to a driving current flowing from the first transistor T1thereto.

An operation of the circuit shown inFIG. 20, particularly the operation during one frame, will hereinafter be described. Here, the operation of an exemplary embodiment where the transistors T1, T2, and T3are an N-channel transistor will be described, but not being limited thereto.

When one frame starts, in an initialization period, the first scan signal SC of a high level and the second scan signal SS of a high level are supplied to turn on the second transistor T2and the third transistor T3. The reference voltage from the data line is supplied to the gate electrode G1of the first transistor T1and one terminal of the capacitor Cst through the turned-on second transistor T2, and the initialization voltage INIT is supplied to the drain electrode D1of the first transistor T1and the anode of the light emitting diode ED through the turned-on third transistor T3. Accordingly, during the initialization period, the drain electrode D1of the first transistor T1and the anode of the light emitting diode (ED are initialized to the initialization voltage INIT. At this time, the capacitor Cst stores a voltage difference between the reference voltage and the initialization voltage INIT.

Next, in a sensing period, when the second scan signal SS becomes a low level in a state that the first scan signal SC of a high level is maintained, the second transistor T2maintains the turn-on state and the third transistor T3is turned off. The gate electrode G1of the first transistor T1and one terminal of the capacitor Cst maintain the reference voltage through the turned-on second transistor T2, and the drain electrode D1of the first transistor T1and the anode of the light emitting diode ED are disconnected from the initialization voltage INIT through the turned-off third transistor T3. Accordingly, the first transistor T1is turned off when the current flows from the source electrode S1to the drain electrode D1, and then the voltage of the drain electrode D1becomes a reference voltage or Vth). Vth represents a threshold voltage of the first transistor T1. At this time, the voltage difference between the gate electrode G1and the drain electrode D1of the first transistor T1is stored in the capacitor Cst, and the sensing of the threshold voltage Vth of the first transistor T1is completed. By generating the data signal that is compensated by reflecting the sensed characteristic information during the sensing period, a characteristic deviation of the first transistor T1which may be different for each pixel may be externally compensated.

Next, in a data input period, when the first scan signal SC of a high level is supplied and the second scan signal SS of a low level is supplied, the second transistor T2is turned on and the third transistor T3is turned off. The data voltage DAT from the data line is supplied to one terminal of the capacitor Cst and the gate electrode G1of the first transistor T1via the second turned-on transistor T2. In the data input period, the anode of the drain electrode D1and the light emitting diode ED of the first transistor T1may substantially maintain the potential in the sensing period by the first transistor T1in the turn-off state.

Next, in a light emission period, the first transistor T1that is turned on by the data voltage DAT transmitted to the gate electrode G1generates the driving current corresponding to the data voltage DAT, and the light emitting diode (ED may emit light having a luminance corresponding to the driving current.

FIG. 21is a plan layout view of a plurality of pixels PX1, PX2, and PX3of a display substrate100according to an exemplary embodiment, andFIG. 22is a cross-sectional view of a display device shown inFIG. 21taken along line XXII-XXII′.FIG. 23toFIG. 25are cross-sectional views showing a display device according to alternative exemplary embodiments.

Referring toFIG. 21andFIG. 22, an exemplary embodiment of the display substrate100may include the first substrate110. The first substrate110may include an insulating material, such as glass or plastic, and may have flexibility.

In an exemplary embodiment, a lower layer including a plurality of lower patterns111a,111b, and111cas a first conductive layer is disposed on the first substrate110. In one exemplary embodiment, for example, a barrier layer (not shown) of an insulating layer may be disposed between the first substrate110and the lower layer The lower layer is conductive, and may include a semiconductor material including at least one selected from various conductive metals or having conductive characteristics similar thereto. Alternatively, the lower layer may be omitted.

A buffer layer120of an insulating layer is disposed on the lower layer. In such an embodiment, the lower layer may be disposed between the first substrate110and the buffer layer120.

An active layer including a plurality of active patterns130a,130b, and130cis disposed on the buffer layer120. in such an embodiment, the lower layer may be disposed between the first substrate110and the active layer. The active patterns130a,130b, and130cdisposed in each pixel PX1, PX2, and PX3may include a channel region134a,134b, and134cforming each channel of the plurality of transistors T1, T2, and T3described above, and a conductive region connected thereto. The conductive region of the active patterns130a,130b, and130cincludes a source region133a,133b, and133cand a drain region135a,135b, and135cof each transistor T1, T2, and T3. In each pixel PX1, PX2, and PX3, the active pattern130aand the active pattern130cmay be connected to each other.

The active layer may include a semiconductor material such as an amorphous silicon, a polysilicon, or an oxide semiconductor.

An insulating pattern144of a first insulating layer is disposed on the active layer. In an exemplary embodiment, the insulating pattern144overlaps the channel regions134a,134b, and134cof the active patterns130a,130b, and130c, and may be disposed on the channel regions134a,134b, and134c. The insulating pattern144may not substantially overlap the conductive region of the active patterns130a,130b, and130c.

A second conductive layer may be disposed on the insulating pattern144. The second conductive layer may include a first scan line151that transmits the first scan signal SC as described above, a second scan line152that transmits the second scan signal SS, a transverse initialization voltage line153that transmits the initialization voltage INIT, a transverse driving voltage line172bthat transmits the driving voltage ELVDD, a driving gate electrode155, a second gate electrode154b, a third gate electrode154c, and the like. The gate electrode G1, the gate electrode G2, and the gate electrode G3in the above-described circuit diagram respectively correspond to a first gate electrode154a, the second gate electrode154b, and the third gate electrode154c.

The first and second scan lines151and152, the transverse initialization voltage line153, and the transverse driving voltage line172bmay extend in a first direction DR1, respectively. The driving gate electrode155may be disposed between the first scan line151and the second scan line152. The second gate electrode154bis connected to the first scan line151, and may have a shape that is protruded downwardly from the first scan line151. The third gate electrode154cis connected to the second scan line152, and may have a shape that is protruded upwardly from the second scan line152.

The driving gate electrode155disposed in each pixel PX1, PX2, and PX3may include an extension155aprotruded upwardly and extending substantially in a second direction DR2crossing the first direction DR1, and the first gate electrode154aprotruded downwardly and extending substantially in the second direction DR2. The first gate electrode154adisposed in the pixel PX3may be folded at least twice at a portion connected to the driving gate electrode155. Herein, a third direction DR3may be a direction perpendicular to the first direction DR1and the second direction DR2.

The first gate electrode154acrosses the active pattern130aand overlaps the channel region134aof the active pattern130a. The second gate electrode154bcrosses the active pattern130band overlaps the channel region134bof the active pattern130b. The third gate electrode154ccrosses the active pattern130cand overlaps the channel region134cof the active pattern130c.

A second insulating layer161may be disposed on the second conductive layer. In an exemplary embodiment, a plurality of contact holes24,26,60,61,62,63,64,65,66,67,68, and69may be defined through the buffer layer120and/or the second insulating layer161.

A third conductive layer may be disposed on the second insulating layer161. The third conductive layer may include a plurality of data lines171a,171b, and171c, a driving voltage line172a, a common voltage line170, an initialization voltage line173, a capacitor electrode175, a plurality of connecting members174,176,177, and178, and a plurality of driving voltage patterns172cand172d.

The data lines171a,171b, and171c, the driving voltage line172a, the common voltage line170, the initialization voltage line173, and the driving voltage patterns172cand172dextend substantially in the second direction DR2to be elongated, thereby crossing the first scan line151and/or the second scan line152.

A plurality of pixels PX1, PX2, and PX3of one group shown and repeated inFIG. 21may be repeatedly arranged in the first direction DR1and adjacent to each other. The common voltage line170may be disposed at both of right and left sides of the plurality of pixels PX1, PX2, and PX3of one group. In an exemplary embodiment, the common voltage line170may be provided for each of a plurality of pixels PX1, PX2, and PX3of one repeated group. In an exemplary embodiment, where the plurality of pixels PX1, PX2, and PX3of one repeated group include three pixels PX1, PX2and PX3, the data lines171a,171b, and171c, at least one driving voltage line172aand at least one initialization voltage line173may be disposed between two adjacent common voltage lines170.

Each data line171a,171b, and171cis electrically connected to the source region133bof the active pattern130bthrough at least one contact hole64(FIG. 21shows two contact holes64in each pixel PX1, PX2, and PX3) of the second insulating layer161.

FIG. 21shows one data line171a, and each of the data lines171a,171b, and171cmay include an end portion179. The end portion179may be disposed in a pad region disposed at the edge of the display device.

The driving voltage line172amay be disposed in one pixel, for example, the pixel PX1, and the driving voltage patterns172cand172dmay be disposed in the other pixels PX2and PX3, respectively. Each driving voltage line172amay extend in the second direction DR2to extend adjacent to the plurality of pixels. In such an embodiment, the driving voltage line172amay include an end portion172edisposed in the pad region as the data line171a.

The driving voltage line172aand the driving voltage patterns172cand172dare electrically connected to the source region133aof the active pattern130athrough at least one contact hole61(FIG. 2shows two contact holes61of the pixels PX1and PX2and one contact hole61of the pixel PX3) of the second insulating layer161. In such an embodiment, the driving voltage line172aand the driving voltage patterns172cand172dare electrically connected to the transverse driving voltage line172bthrough at least one contact hole60(FIG. 2shows two contact holes60of each pixel PX1, PX2, and PX3) of the second insulating layer161. Therefore, the transverse driving voltage line172band the driving voltage patterns172cand172dmay transmit the driving voltage ELVDD together with the driving voltage line172a, and the driving voltage ELVDD in the entire display device may be transmitted in a mesh shape in both of the first direction DR1and the second direction DR2.

The initialization voltage line173is electrically connected to the transverse initialization voltage line153through the contact hole69of the second insulating layer161. Therefore, the transverse initialization voltage line153may transfer the initialization voltage INIT along with the initialization voltage line173, and even if the initialization voltage line173is provided for each of the three pixels PX1, PX2, and PX3, the initialization voltage INIT may be transmitted to all pixels PX1, PX2, and PX3through the transverse initialization voltage line153.

The capacitor electrode175may be included in each pixel PX1, PX2, and PX3. The capacitor electrode175may overlap the corresponding driving gate electrode155via the second insulating layer161therebetween, thereby forming the capacitor Cst.

The capacitor electrode175may include a connection175aprotruded downwardly. The connection175ais electrically connected to the drain region135aof the active pattern130aand the source region133cof the active pattern130cconnected thereto through at least one contact hole62(FIG. 2shows three contact holes62of each pixel PX1, PX2, and PX3) of the second insulating layer161. in such an embodiment, the capacitor electrode175is electrically connected to the lower pattern111avia the contact hole68of the second insulating layer161and the buffer layer120.

The connecting member174is electrically connected to the second scan line152and the lower pattern111cvia two contact holes24of the buffer layer120and the second insulating layer161, or a contact hole defined only through the second insulating layer161, thereby electrically connecting the second scan line152and the lower pattern111c.

The connecting member176is electrically connected to the first scan line151and the lower pattern111bvia two contact holes26of the buffer layer120and the second insulating layer161, or a contact hole defined only through the second insulating layer161, thereby electrically connecting the first scan line151and the lower pattern111b.

The connecting member177is electrically connected to the drain region135cof the active pattern130cvia at least one contact hole63(FIG. 2shows two contact holes63in each pixel PX1, PX2, and PX3) of the second insulating layer161in each pixel PX1, PX2, and PX3, and is electrically connected to the transverse initialization voltage line153via the contact hole67of the second insulating layer161, such that the drain region135cof the active pattern130cmay be electrically connected to the transverse initialization voltage line153.

The transverse initialization voltage line153extends in the first direction DR1throughout three pixels PX1, PX2, and PX3. Alternatively, the transverse initialization voltage line153may be disposed between two adjacent common voltage lines170and not cross the two common voltage lines170. The transverse initialization voltage line153crosses three adjacent data lines171a,171b, and171c, and may extend to the initialization voltage line173.

The connecting member178is electrically connected to the drain region135bof the active pattern130bvia at least one contact hole65(FIG. 2shows two contact holes65in each pixel PX1, PX2, and PX3) of the second insulating layer161in each pixel PX1, PX2, and PX3, and is electrically connected to the extension155aof the driving gate electrode155via the contact hole66of the second insulating layer161, thereby the drain region135bof the active pattern130band the extension155aof the driving gate electrode155may be electrically connected to each other.

At least one layer selected from the first conductive layer, the second conductive layer, and the third conductive layer may include at least one metal such as copper (Cu), aluminum (Al), magnesium (Mg), silver (Ag), gold (Au), platinum (pt), palladium (Pd), nickel (Ni), neodymium (Nd), iridium (Ir), molybdenum (Mo), tungsten (W), titanium (Ti), chromium (Cr), tantalum (Ta), alloys thereof, and the like. Each of the first conductive layer, the second conductive layer, and the third conductive layer may have a single layer structure or a multi-layer structure.

In one exemplary embodiment, for example, the third conductive layer may have a multilayer structure including an underlying layer including titanium and an overlying layer including copper.

The first transistor T1includes the channel region134a, the source region133a, the drain region135a, and the first gate electrode154a. The source region133aof the first transistor T1is electrically connected to the driving voltage line172aand the driving voltage patterns172cand172d, thereby receiving the driving voltage ELVDD.

The lower pattern111acorresponding to the first transistor T1overlaps the channel region134abetween the channel region134aof the first transistor T1and the substrate110to prevent external light from reaching the channel region134a, thereby reducing a leakage current and a characteristic deterioration. The lower pattern111ais electrically connected to the drain region135aof the first transistor T1through the capacitor electrode175.

The second transistor T2includes the channel region134b, the source region133b, the drain region135b, and the second gate electrode154b. The source region133bof the second transistor T2is electrically connected to the data lines171a,171b, and171c, thereby receiving the data voltage DAT or the reference voltage. The drain region135bof the second transistor T2may be electrically connected to the first gate electrode154athrough the driving gate electrode155.

The lower pattern111bcorresponding to the second transistor T2overlaps the channel region134bbetween the channel region134bof the second transistor T2and the substrate110to prevent the external light from reaching the channel region134b, thereby reducing the leakage current and the characteristic deterioration. In such an embodiment, the lower pattern111b, which is electrically connected to the first scan line151, may define a dual gate electrode of the second transistor T2or the second gate electrode154b.

The third transistor T3includes the channel region134c, the source region133c, the drain region135c, and the third gate electrode154c. The drain region135cof the third transistor T3may receive the initialization voltage INIT from the transverse initialization voltage line153.

The lower pattern111ccorresponding to the third transistor T3overlaps the channel region134cbetween the channel region134cof the third transistor T3and the substrate110to prevent the external light from reaching the channel region134c, thereby reducing the leakage current and the characteristic deterioration. In such an embodiment, the lower pattern111c, which is electrically connected to the second scan line152, may define the dual gate electrode of the third transistor T3or the third gate electrode154c.

A third insulating layer181may be disposed on the second insulating layer161and the third conductive layer. The third insulating layer181may include a contact hole83adisposed on the capacitor electrode175, a contact hole89adisposed on the end portion179of the data lines171a,171b, and171c, and a contact hole81disposed on the common voltage line170.

A fourth conductive layer including a plurality of ohmic contacts190a,190b,190c,190d, and190emay be disposed on the third insulating layer181.

The ohmic contact190a,190b, and190cmay be respectively disposed in the pixels PX1, PX2, and PX3and in contact with the capacitor electrode175via the contact hole83ato be electrically connected. The ohmic contact190dmay be in contact with the common voltage line170via the contact hole81to be electrically connected. The ohmic contact190emay be in contact with the end portion179of the data lines171a,171b, and171cvia the contact hole89ato be electrically connected.

The ohmic contacts190a,190b,190c,190dand190emay improve the adherence of the capacitor electrode175of the third conductive layer, the common voltage line170, and the end portion179of the data lines171a,171b, and171c, which are in contact thereto, with other conductive layers, and may prevent oxidation of the third conductive layer. In an exemplary embodiment, the upper layer of the third conductive layer includes copper, such that oxidation of the copper may be prevented by the fourth conductive layer. In such an embodiment, when the upper layer of the third conductive layer includes the conductive material for preventing corrosion of the upper layer of the third conductive layer, for example, copper, the fourth conductive layer may include the conductive material by capping the upper layer of the third conductive layer to prevent the corrosion thereof. In one exemplary embodiment, for example, the fourth conductive layer may include the conductive material of the metal oxide such as indium tin oxide (“ITO”), indium zinc oxide (“IZO”), and the like.

A fourth insulating layer182may be disposed on the third insulating layer181and the fourth conductive layer. A contact hole83bmay be defined through the fourth insulating layer182may include to expose each ohmic contact190a,190b, and190cand overlapping the contact hole83a, and a contact hole89bdisposed on the ohmic contact190eand overlapping the contact hole89a. An opening355corresponding to the contact hole89bmay be defined through the partition350over the fourth insulating layer182.

The ohmic contact (contact member)190emay be exposed by the contact hole89b, and thereby may be in electrical contact with a separate driving circuit chip, circuit film, or circuit board.

At least one selected from the buffer layer120, the first insulating layer, the second insulating layer161, the third insulating layer181, and the fourth insulating layer182may include an inorganic insulating material such as a silicon nitride (SiNx), a silicon oxide (SiOx), and a silicon oxynitride (SiON), and/or an organic insulating material. in an exemplary embodiment, the fourth insulating layer182may include the inorganic insulating material and/or the organic insulating material such as a polyimide, an acryl-based polymer, a siloxane-based polymer, or the like, and may have a substantially flat upper surface. The fourth insulating layer182will be described later in greater detail.

In an exemplary embodiment, a pixel electrode layer including a plurality of pixel electrodes191a,191b, and191cmay be disposed as a fifth conductive layer on the fourth insulating layer182. The first electrode191may include a first pixel electrode191a, a second pixel electrode191b, and a third pixel electrode191c. The pixel electrodes191a,191b, and191cmay be disposed corresponding to the pixels PX1, PX2, and PX3, respectively, as shown inFIG. 21.

Planar sizes and shapes of the first pixel electrode191a, the second pixel electrode191b, and the third pixel electrode191cmay differ from each other.

In one exemplary embodiment, for example, in the three pixels PX1, PX2, and PX3, a planar size of the second pixel electrode191b, a planar size of the first pixel electrode191a, and a planar size of the third pixel electrode191cmay be reduced in that order. In such an embodiment, the pixel PX2may represent green, the pixel PX1may represent red, and the pixel PX3may represent blue.

Alternatively, the planar size of the first pixel electrode191amay be the largest, and the planar size of the second pixel electrode191bmay be greater than the planar size the third pixel electrode191c.

The pixel electrodes191a,191b, and191cmay respectively be in contact with the ohmic contacts (the contact members)190a,190b, and190cthrough the contact hole83band electrically connected to the capacitor electrode175through the ohmic contacts190a,190b, and190c. Accordingly, each pixel electrode191a,191b, and191cis electrically connected to the drain region135aof the first transistor T1, thereby receiving the voltage from the first transistor T1.

The pixel electrode layer may include a semitransparent conductive material or a reflective conductive material.

The partition350may be disposed on the fourth insulating layer182. The partition350has the opening355disposed on the pixel electrode191a,191b, and191c. The partition350may include an organic material or an inorganic material. In one exemplary embodiment, for example, the partition350may include an inorganic material including silicon. The partition350may include at least one selected from SiOx, SiNx, SiON, and siloxane. In such an embodiment, the partition350may further include carbon in the inorganic material including silicon.

In a case where the partition350includes the inorganic material including Si, the absorption of light of lower wavelengths is relatively low compared with a case where the partition350includes the organic material. In an exemplary embodiment, the partition350includes an inorganic material having a low light absorption, such that the amount that the light reflected by the first electrode191disposed in the second region A2is absorbed to the partition350is reduced, thereby increasing the light emission efficiency. to The light-emitting element layer370is disposed on the partition350and the pixel electrode layer. The light-emitting element layer370may include a part disposed within the opening355of the partition350. The light-emitting element layer370may include an organic light emission material or an inorganic light emission material.

The second electrode270is disposed on the light-emitting element layer370. The second electrode270may be a common electrode. The second electrode270may be formed continuously across the plurality of pixels PX1, PX2, and PX3. The second electrode270may be electrically connected to the common voltage line170by being in contact with the ohmic contact190dthrough a contact hole82, thereby receiving the common voltage ELVSS.

The second electrode270may include a conductive transparent material.

The pixel electrodes191a,191b, and191c, the light-emitting element layer370, and the common electrode270of each pixel PX1, PX2, and PX3collectively define the light emitting diode ED, and one of the pixel electrodes191a,191band191c, and the common electrode270may be the cathode, and the other the pixel electrodes191a,191band191c, and the common electrode270may be the anode. For convenience of description, exemplary embodiments where the pixel electrodes191a,191b, and191care the anode is described herein.

Referring toFIG. 21, the lower pattern111amay further include an extension portion111aaoverlapping the driving voltage lines172aand the driving voltage patterns172cand172din a plan view. Accordingly, the plane size of the lower pattern111amay be larger than the plane size of the lower pattern111bor the lower pattern111c. According to an exemplary embodiment, the lower pattern111ais electrically connected to the pixel electrodes191a,191b, and191cas the anode via the capacitor electrode175, and as the extension portion111aaof the lower pattern111aoverlaps the driving voltage line172aand the driving voltage patterns172cand172dfor transmitting a predetermined voltage via the buffer layer120and the second insulating layer161, a capacitor Ced for maintaining the voltage of the anode.

The extension portion111aamay also overlap the source region133aof the active pattern130aconnected to the driving voltage line172a.

In an exemplary embodiment, the lower pattern111ais electrically connected to the pixel electrodes191a,191b, and191cthrough the capacitor electrode175and also overlaps the channel region134aof the first transistor T1, and a current variation rate is reduced in a saturation region of a voltage-current characteristic graph of the first transistor T1so that a range of a region where the output current of the first transistor T1is constant may be widened. Therefore, even if there is a change in the source-drain voltage Vds of the first transistor T1, the output current of the first transistor T1is maintained at a constant level, thereby improving the output saturation characteristic. Thus, the luminance deviation between the pixels due to the output current of the first transistor T1is reduced, thereby improving the image quality.

Referring toFIG. 22, the fourth insulating layer182includes the first region A1, the second region A2, and the third region A3. The first region A1has a smaller thickness than the third region A3. In such an embodiment, the top of the first region A1is disposed closer to the first substrate110than the top of the third region A3. The second region A2has the inclined surface as the part connecting the first region A1and the third region A3. The first electrode191is disposed on the inclined surface of the second region A2, and the first electrode191reflects the light emitted from the light-emitting element layer370to the side surface to increase the light emission efficiency.

In an exemplary embodiment ofFIG. 22, the partition350may include an inorganic material including silicon. In one exemplary embodiment, for example, the partition350may include at least one selected from SiOx, SiNx, SiON, and siloxane. In such an embodiment, the partition350may further include carbon in the inorganic material including silicon.

In such an embodiment, the display device has a similar structure to that of the exemplary embodiment ofFIG. 1having improved light emission efficiency. Accordingly, any repetitive detailed description thereof will be omitted.

FIG. 23is a cross-sectional view showing a display device according to another alternative exemplary embodiment. Referring toFIG. 23, an exemplary embodiment of the display device includes the reflection member410disposed between the insulating layer180and the first electrode191. The exemplary embodiment ofFIG. 23corresponds to the exemplary embodiment ofFIG. 5. The same or like elements shown inFIG. 23have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 5, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

Referring toFIG. 23, in an exemplary embodiment, the side surface of the reflection member410may be inclined. The first electrode191may be disposed on the inclined side surface and the flat upper surface of the reflection member410. Since the first electrode191has the inclined side surface along the side surface of the reflection member410, as inFIG. 22, the light emitted to the side surface of the light-emitting element layer370is reflected by the reflection member410and the first electrode191, thereby increasing the light emission efficiency.

FIG. 24is a cross-sectional view showing the same cross-section asFIG. 22according to another alternative exemplary embodiment. Referring toFIG. 24, an exemplary embodiment of the display device includes the reflection member410disposed on the first electrode191. The exemplary embodiment ofFIG. 24corresponds to the exemplary embodiment ofFIG. 8. The same or like elements shown inFIG. 24have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 8, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

In such an embodiment, the side surface of the reflection member410may be inclined. The light emitted to the side surface of the light-emitting element layer370may be reflected by the reflection member410to increase the light emission efficiency. Referring toFIG. 24, one edge of the reflection member410and one edge of the first electrode191may be disposed on a same plane. In such an embodiment, one side surface of the reflection member410and one side surface of the first electrode191form a same inclined surface. In such an embodiment, the reflection member410and the first electrode191may be formed by a same process.

FIG. 25is a cross-sectional view showing a display device according to another alternative exemplary embodiment. The exemplary embodiment of the display device shown inFIG. 25is substantially the same as the exemplary embodiment described above with reference toFIG. 24, except that the side edge of the reflection member410is not aligned with the side edge of the first electrode191. The same or like elements shown inFIG. 25have been labeled with the same reference characters as used above to describe the exemplary embodiment of the display device shown inFIG. 24, and any repetitive detailed description thereof will hereinafter be omitted or simplified.

As described herein, in exemplary embodiments of the display device according to the invention, the insulating layer includes an inclined surface or includes the reflection member including an inclined surface. Accordingly, in such embodiment, the light emission efficiency is increased by reflecting the light emitted to the side surface of the light-emitting element by the first electrode. In such embodiments, the partition includes an inorganic material, such that the transmittance of the light reflected by the first electrode is increased, and the partition includes a material having a refractive index similar to that of the light-emitting element layer, thereby allowing the light reflected by the first electrode to exit through an interface between the light-emitting element layer and the partition. Thus, the light emission efficiency of the display device is increased.