Patent Description:
An electroluminescent display device as new flat panel display is a self-emission type without a backlight unit. Accordingly, in comparison to other display device, e.g., a liquid crystal display device, the electroluminescent display device has advantages in the viewing angle, the contrast ratio, the thin profile, the light weight and the power consumption. In addition, the electroluminescent display device can be driven by a low DC voltage and has fast response time. Moreover, the electroluminescent display device has more impact-resistance and low production costs.

<FIG> is a schematic cross-sectional view of the related art electroluminescent display device. As shown in <FIG>, the related art electroluminescent display device <NUM> includes a substrate <NUM> including a pixel region, a driving TFT Td on or over the substrate <NUM> and a light emitting diode D connected to the TFT Td. The substrate <NUM> may be a glass substrate or a plastic substrate. A semiconductor layer <NUM> is formed on the substrate <NUM>. The semiconductor layer <NUM> may be formed of an oxide semiconductor material or a poly-silicon. A gate insulating layer <NUM> is formed on the semiconductor layer <NUM>. The gate insulating layer <NUM> may be formed of an inorganic insulating material such as silicon oxide or silicon nitride. A gate electrode <NUM>, which is formed of a conductive material, e.g., metal, is formed on the gate insulating layer <NUM> to correspond to a center of the semiconductor layer <NUM>. An interlayer insulating layer <NUM>, which is formed of an insulating material, is formed on an entire surface of the substrate <NUM>. The interlayer insulating layer <NUM> may be formed of an inorganic insulating material, e.g., silicon oxide or silicon nitride, or an organic insulating material, e.g., benzocyclobutene or photo-acryl. The interlayer insulating layer <NUM> includes first and second contact holes <NUM> and <NUM> exposing both sides of the semiconductor layer <NUM>. The first and second contact holes <NUM> and <NUM> are positioned at both sides of the gate electrode <NUM> to be spaced apart from the gate electrode <NUM>.

A source electrode <NUM> and a drain electrode <NUM>, which are formed of a conductive material, e.g., metal, are formed on the interlayer insulating layer <NUM>. The source electrode <NUM> and the drain electrode <NUM> are spaced apart from each other with respect to the gate electrode <NUM> and respectively contact both sides of the semiconductor layer <NUM> through the first and second contact holes <NUM> and <NUM>. The semiconductor layer <NUM>, the gate electrode <NUM>, the source electrode <NUM> and the drain electrode <NUM> constitute the driving TFT Td.

Although not shown, a gate line and a data line are disposed on or over the substrate <NUM> and cross each other to define a pixel region. In addition, a switching element, which is electrically connected to the gate line and the data line, and a power line, which is parallel to and spaced apart from the gate line or the data line, may be disposed on or over the substrate <NUM>. The switching element is electrically connected to the TFT Tr as the driving element. Moreover, a storage capacitor for maintaining a voltage of the gate electrode <NUM> of the TFT Tr during one frame may be further formed on the substrate <NUM>. A passivation layer <NUM>, which includes a drain contact hole <NUM> exposing the drain electrode <NUM> of the driving TFT Td, is formed to cover the driving TFT Td. A first electrode <NUM>, which is connected to the drain electrode <NUM> of the driving TFT Td through the drain contact hole <NUM>, is separately formed on the passivation layer <NUM>. In addition, a bank layer <NUM>, which has an opening for exposing a center of the first electrode <NUM> and covers an edge of the first electrode <NUM>, is formed on the passivation layer <NUM>. An emitting layer <NUM> and a second electrode <NUM> are sequentially formed on the first electrode <NUM>. The first electrode <NUM>, the second electrode <NUM> facing the first electrode <NUM> and the emitting layer <NUM> therebetween constitute the light emitting diode D.

Generally, the emitting layer <NUM> is formed by a thermal depositing process. However, there is a limitation in the thermal deposition for the emitting layer <NUM> of a large-size display device. Hence, an alternative process of using a solution and then vaporizing the solution to solidify the emitting layer <NUM>, known as, a solution process may be used.

However, when the emitting layer <NUM> is formed by the solution process, the thickness in the emitting layer of pixel regions may be become inconsistent at different pixels, decreasing the quality and the lifetime of the electroluminescent display device. <CIT> relates to an organic EL device which includes a first bank defining a color producing region and a second bank defining a plurality of pixels in the color producing region. A groove is formed on the top face of the first bank. On the top face of the second bank, another groove is formed,
<CIT> describes an organic light emitting display panel. A plurality of grooves or holes are positioned in a bank. <CIT> discloses an organic light-emitting display substrate including a plurality of dams crisscrossing in a display area, wherein a groove is arranged on a top surface of each dam. <CIT> relates to an electroluminescent device. An electroluminescent layer in red is formed in first pixel aperture, an electroluminescent layer in green is formed in a second pixel aperture, and an electroluminescent layer in blue is formed in a third pixel aperture. A first connection channel is located at an upper side of the corresponding row of the pixel apertures and connected to all the first pixel apertures in the corresponding row. A second connection channel is located at a lower side of the corresponding row of the pixel apertures and connected to all second pixel apertures in the corresponding row. <CIT> discloses a manufacturing method of an organic electroluminescence device which comprises a process of forming a partition wall for partitioning a plurality of picture elements on a base board and a process of arranging the ink including a forming material of a light emitting element in an area partitioned by the partition wall. The forming process of the partition wall includes a process of forming a mist absorbing structure which is a recessed part. <CIT> discloses a substrate for organic electroluminescence devices. The substrate comprises a support substrate whereupon a plurality of pixel electrode arrays are formed in parallel and partitions. The partitions and the pixel electrode arrays are arranged alternately in a stripe arrangement, and protrusions that narrow the spaces between the partitions are formed between the pixel electrodes.

The object is solved by the features of the independent claim. Preferred embodiments are given by the dependent claims. Any "aspect", "example" and "embodiment" of the description not falling within the scope of the claims does not form part of the invention and is provided for illustrative purposes only.

Embodiments according to the present invention relate to an electroluminescent display device as claimed in claim <NUM>. The second pixel is separated from the first pixel in the second direction by the second edge distance larger than the first edge distance.

In one or more embodiments, the indent has a different width along a length of the indent.

In one or more embodiments, the indent has a first width between the first pixel and the other first pixel, and the indent has a second width between the first pixel and the second pixel, the second width being narrower than the first width.

In one or more embodiments, at least one indent includes a first indent and a second indent between the first pixel and the second pixel, the first indent closer to the first pixel than the second pixel, the second indent closer to the second pixel than the first pixel. The edge distance between the first indent and the first pixel is same as an edge distance between the second indent and the second pixel.

In one or more embodiments, the first, the other first and the second pixels have round edges.

In one or more embodiments, the at least one indent comprises a first groove and a second groove, the first groove having a first linear bar portion extending alongside a row of pixels and first bump portions protruding towards gaps between the row of pixels, and the second groove having a second linear bar portion extending parallel to the first linear bar portion and having second bump portions protruding towards gaps between another row of pixels including the second pixel.

In one or more embodiments, an edge distance between an edge of the first pixel and a first bump portion nearest to the edge of the first pixel is same as an edge distance between an end of the first pixel and the first linear bar portion, and wherein an edge distance between an edge of the second pixel and a second bump portion nearest to the edge of the second pixel is same as an edge distance between an end of the second pixel and the second linear bar portion.

In one or more embodiments, at least one groove or hole comprises a linear bar portion extending alongside a row of pixels, first bump portions protruding towards gaps between the row of pixels, and second bump portions protruding towards gaps between another row of pixels including the second pixel.

In one or more embodiments, an edge distance between the first pixel and a nearest first portion is same as an edge distance between the first pixel and the linear bar portion.

In one or more embodiments, the at least one indent comprises a first linear bar portion extending alongside a row of pixels, first holes between the first linear bar portion and the row of pixels, second linear bar portion extending parallel to the first linear bar portion, and second holes between the second linear bar portion and another row of pixels including the second pixel.

In one or more embodiments, an edge distance from an edge of the first pixel to a nearest first hole is same as an edge distance from an end of the first pixel to the first linear bar portion, and an edge distance from an edge of the second pixel to a nearest second hole is same as an edge distance from an end of the second pixel to the second linear bar portion.

In one or more embodiments, the at least one groove or hole comprises a linear bar portion extending alongside a row of pixels, first holes between the linear bar portion and the row of pixels, and second holes between the linear bar portion and another row of pixels including the second pixel.

In one or more embodiments, an edge distance between the first pixel and a nearest first hole is same as an edge distance between the first pixel and the linear bar portion, and an edge distance between the second pixel and a nearest second hole is same as an edge distance from the second pixel to the linear bar portion.

In one or more embodiments, the electroluminescent display device further includes a bank layer defining the first pixel, the other first pixel and the second pixel; and an electrode covering the bank layer, the electrode forming a bottom of the at least one indent.

In one or more embodiments, each of the first, second and other first pixels comprises a driving transistor, a portion of a layer on or above the driving transistor, a first electrode connected to a terminal of the driving transistor, an emitting layer on the first electrode, and a second electrode on the emitting layer, the second electrode extending over a bank layer and the at least one indent, wherein the at least one indent is filled with solidified emitting material.

In one or more embodiments, the solidified emitting material in the at least one groove or hole is not connected to the first electrode but connected to the second electrode.

In one or more embodiments, the layer on or above the driving transistor is a passivation layer.

In a further example an electroluminescent display device is provided, wherein the first indent positioned between the first and second pixels and including a first portion extending along the first direction further includes a second portion corresponding to the first and the other first pixels.

In one or more embodiments, the second portion protrudes toward a gap between the first pixel and the other first pixel from the first portion.

In one or more embodiments, the second portion is spaced apart from the first portion.

In one or more embodiments, an edge distance from the first portion of the first indent to the first and other first pixels is equal to an edge distance from the second portion of the first indent to each of the first and the other first pixels.

In one or more embodiments, the electroluminescent display device may further comprise a other second pixel on the substrate. The other second pixel is separated from the second pixel in the first direction. A second indent is provided between the first indent and second pixel, wherein the second indent including a third portion extending along the first direction and a fourth portion corresponding to the second and the other second pixels.

In one or more embodiments, the fourth portion protrudes toward a gap between the second pixel and the other second pixel from the third portion.

In one or more embodiments, an edge distance from the third portion of the second indent to the second and the other second pixels is equal to an edge distance from the fourth portion of the second indent to each of the second and the other second pixels.

In one or more embodiments, the fourth portion is spaced apart from the third portion.

In one or more embodiments, the electroluminescent display device may further comprise a another second pixel on the substrate, the other second pixel separated from the second pixel in the first direction, wherein the first indent further includes a third portion corresponding to the second and the other second pixels.

In one or more embodiments, the third portion protrudes toward a gap between the second pixel and the other second pixel from the first portion.

In one or more embodiments, an edge distance from the first portion of the first indent to the second and the other second pixels is equal to an edge distance from the third portion of the first indent to each of the second and the other second pixels.

In one or more embodiments, the third portion is spaced apart from the first portion.

In one or more embodiments, the electroluminescent display device may further comprise at least one of a thin film transistor between the substrate and the light emitting diode; an insulating layer covering the thin film transistor and positioned between the thin film transistor and the light emitting diode; and the bank layer on the insulating layer and surrounding the first and other first pixels, wherein the light emitting diode includes a first electrode on the insulating layer and in each of the first and the other first pixels, an emitting layer on the first electrode and a second electrode covering the emitting layer.

In one or more embodiments, the first indent may comprise an auxiliary material pattern, wherein the auxiliary material pattern contacts the insulating layer and the second electrode.

In one or more embodiments, the second electrode in the first indent contacts the insulating layer.

In one or more embodiments, the first indent has a depth equal to a thickness of the bank layer.

In one or more embodiments, the second electrode has a first height in the first indent from the substrate and a second height in each of the first and the other first pixels from the substrate, and the first height is smaller than the second height.

In one or more embodiments, a width of the first indent is smaller than a distance between the first and the other first pixels.

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the principles of the disclosure. Any "aspect", "example" and "embodiment" of the description not falling within the scope of the claims, such as the examples in <FIG>, <FIG>, does not form part of the invention and is provided for illustrative purposes only.

As mentioned above, when the emitting layer is formed by the solution process, the thickness deviation problem of the emitting layer is generated. The reason of the thickness deviation problem may be a difference in a solvent concentration in the air according to a position of the pixel region. It is explained in more detail.

A pixel described herein may include multiple sub-pixels or consist of a sub-pixel.

An edge distance of two objects described herein refers to a distance between closest edges of the two objects.

<FIG> is a schematic view illustrating a thickness non-uniformity problem in the emitting layer. In the electroluminescent display device <NUM>, a plurality of first pixels P1 and a plurality of second pixels P2 are arranged. The first pixels P1 are arranged in a first row along a first direction (e.g., horizontally), and the second pixels P2 are arranged in a second row. The second pixels P2 are spaced apart from the first pixels P1 in a second direction (e.g., vertically) being perpendicular to the first direction.

Adjacent two of the first pixels P1 and adjacent two of the second pixels P2 are spaced apart from each other by a first edge distance d1, and the first pixel P1 and the second pixel P2 are spaced apart from each other by a second edge distance d2 that is greater than the first edge distance d1.

In the solution process for forming the emitting layer of the light emitting diode, emitting material solution is first coated, and then the solvent in the emitting material solution is evaporated, for example, in a vacuum chamber. In this instance, before loading the substrate coated with the emitting material solution onto the vacuum chamber, the solvent in the emitting material solution is spontaneously evaporated. In the spontaneous evaporation, a solvent concentration in a space between adjacent first pixels P1 or adjacent second pixels P2 becomes different from that in a space between adjacent first and second pixels P1 and P2. That is, compared to ends of the first pixel P1 or the second pixel P2 in the first direction, the solvent is more rapidly evaporated in ends of the first and second pixels P1 and P2 in the second direction. As a result, the emitting layer has a thickness non-uniformity in each pixel region along the first and second directions.

<FIG> is a circuit diagram of one pixel region of an electroluminescent display device. As shown in <FIG>, in an electroluminescent display device, a gate line GL and a data line DL are formed. The gate line GL and the data line DL cross each other to define a pixel region P. In addition, a switching thin film transistor (TFT) Ts, a driving TFT Td, a storage capacitor Cst and a light emitting diode D are provided in the pixel region.

The switching TFT Ts is connected to the gate line GL and the data line DL, and the driving TFT Td and the storage capacitor Cst are respectively connected to the switching TFT Ts and the power line PL. The light emitting diode D is connected to the driving TFT Td.

In the electroluminescent display device, when the switching TFT Ts is turned on by a gate signal applied through the gate line GL, a data signal from the data line DL is applied to a gate electrode of the driving TFT Td and an electrode of the storage capacitor Cst through the switching TFT Ts.

When the driving TFT Td is turned on by the data signal, an electric current is supplied to the light emitting diode D from the high voltage supply VDD through the driving TFT Td. As a result, the light emitting diode D emits light. Since the current in the light emitting diode D is proportional to the data signal and the light intensity emitted from the light emitting diode D is proportional to the current in the light emitting diode D, the pixel region P provide a gray scale according to the data signal.

The storage capacitor Cst serves to maintain the voltage of the gate electrode of the driving TFT Td for one frame. Accordingly, the electroluminescent display device displays a consistent image during the frame.

<FIG> is a schematic plane view of an electroluminescent display device according to a first inventive embodiment. As shown in <FIG>, in an electroluminescent display device <NUM>, a plurality of first pixels P1, a plurality of second pixels P2 and a groove (or an indent) <NUM> are arranged. The first pixels P1 are arranged in a first row along the first direction, and the second pixels P2 are arranged in a second row. The second pixels P2 are spaced apart from the first pixels P1 in the second direction perpendicular to the first direction. The groove <NUM> extends along the first direction and is positioned between the first pixels P1 in the first row and the second pixels P2 in the second row.

Although not shown, a light emitting diode is positioned in each of the first and second pixels P1 and P2. The light emitting diode may include a first electrode, a second electrode facing the first electrode and an emitting layer therebetween. In addition, a driving TFT connected to the light emitting diode is positioned in each of the first and second pixels P1 and P2.

Two adjacent first pixels P1 and two adjacent second pixels P2 are spaced apart from each other by a first edge distance d1, and the first pixel P1 and the adjacent second pixel P2 are spaced apart from each other by a second edge distance d2 that is greater than the first edge distance d1. The groove <NUM> is spaced apart from the first and second pixels P1 and P2 by a third edge distance d3 substantially equal to the first edge distance d1.

The groove <NUM> is positioned between a first horizontal pixel row, where the first pixels P1 are arranged, and a second horizontal pixel row, where the second pixels P2 are arranged. The groove <NUM> is separated by the third edge distance d3 from each of the first and second pixels P1 and P2 (or the first and second horizontal pixel rows). The groove <NUM> may be bar shaped which is parallel to the first and second horizontal pixel rows, but it is not limited thereto. The bar shape of the groove <NUM> is advantageous, among other reasons, because a fabrication process associated with the formation of the groove can be simplified.

When the emitting layer of the light emitting diode is formed by a coating process using the solution in a liquid phase, an emitting material solution including a solvent or only solvent is coated (or dropped) into the groove <NUM> such that the thickness non-uniformity problem of the emitting layer caused by the deviation of a solvent evaporation in the solution process is prevented.

Namely, since the second edge distance d2 between the first pixel P1 and second pixel P2, which are vertically adjacent in a vertical pixel column, is greater than the first edge distance d1 between adjacent first pixels P1 or between adjacent second pixels P2, which are horizontally adjacent in a horizontal pixel row, the thickness deviation of the emitting layer may be generated at a horizontal edge and a vertical edge of each of the first and second pixels P1 and P2 without the groove <NUM>.

However, in the electroluminescent display device of the embodiment, since the groove where the emitting material solution or the solvent is coated is formed between the first pixel P1 and the second pixel P2 with the third edge distance d3, which is substantially equal to the first edge distance d1 from the first and second pixels P1 and P2. This enhances the thickness uniformity of the emitting layer at the horizontal ends and the vertical ends of each pixel P1 and P2. Accordingly, the display quality is improved and the deterioration of lifespan of the electroluminescent display device resulting from the thickness non-uniformity of the emitting material is prevented.

<FIG> is a cross-sectional view taken along the line V-V of <FIG> is a cross-sectional view taken along the line VI-VI of <FIG>. As shown in <FIG>, the electroluminescent display device <NUM> according to the first embodiment includes a substrate <NUM>, where the first pixels P1 adjacent along the first direction and the second pixels P2 adjacent to the first pixel P1 along the second direction are defined, the driving TFT Td on or over the substrate <NUM>, the light emitting diode D connected to the driving TFT Td and the groove <NUM> along the first direction and between the first and second pixels P1 and P2.

On the substrate <NUM>, the gate lines GL (of <FIG>) extend along either the first direction or the second direction, the data lines DL extend along a direction perpendicular to the direction along with the gated lines GL extend, the switching TFT Ts (of <FIG>) and each of the power lines PL may be formed parallel to and spaced apart from a corresponding data line DL. Alternatively, the power line PL may be parallel to and spaced apart from the gate line GL. The gate lines GL and the data lines DL cross each other to define the first and second pixels P1 and P2, and the driving TFT Td is connected to the switching TFT Ts. In addition, the storage capacitor Cst may be formed in each of the first and second pixels P1 and P2. The substrate <NUM> may be a glass substrate or a plastic substrate. A semiconductor layer <NUM> is formed on the substrate <NUM>. The semiconductor layer <NUM> may be formed of an oxide semiconductor material or a poly-silicon.

When the semiconductor layer <NUM> includes the oxide semiconductor material, a light-shielding pattern (not shown) may be formed under the semiconductor layer <NUM>. The light to the semiconductor layer <NUM> is shielded or blocked by the light-shielding pattern such that thermal degradation of the semiconductor layer <NUM> can be prevented. On the other hand, when the semiconductor layer <NUM> includes polycrystalline silicon, impurities may be doped into both sides of the semiconductor layer <NUM>.

A gate insulating layer <NUM> is formed on the semiconductor layer <NUM>. The gate insulating layer <NUM> may be formed of an inorganic insulating material such as silicon oxide or silicon nitride. A gate electrode <NUM>, which is formed of a conductive material, e.g., metal, is formed on the gate insulating layer <NUM> to correspond to a center of the semiconductor layer <NUM>. In addition, the gate line GL and a first capacitor electrode (not shown) of the storage capacitor Cst may be formed on the gate insulating layer <NUM>. The gate line GL may extend along the first direction, and the first capacitor electrode may be connected to the gate electrode <NUM>.

In <FIG>, the gate insulating layer <NUM> is formed across the entire surface of the substrate <NUM>. Alternatively, the gate insulating layer <NUM> may be patterned to have the same shape as the gate electrode <NUM>. An interlayer insulating layer <NUM> formed of an insulating material is formed across an entire surface of the substrate <NUM> including the gate electrode <NUM>. The interlayer insulating layer <NUM> may be formed of an inorganic insulating material, e.g., silicon oxide or silicon nitride, or an organic insulating material, e.g., benzocyclobutene or photo-acryl.

The interlayer insulating layer <NUM> includes first and second contact holes <NUM> and <NUM> exposing both sides of the semiconductor layer <NUM>. The first and second contact holes <NUM> and <NUM> are positioned at both sides of the gate electrode <NUM> to be spaced apart from the gate electrode <NUM>.

In <FIG>, the first and second contact holes <NUM> and <NUM> extend into the gate insulating layer <NUM>. Alternatively, when the gate insulating layer <NUM> is patterned to have the same shape as the gate electrode <NUM>, the first and second contact holes <NUM> and <NUM> may be formed in the interlayer insulating layer <NUM> except the gate insulating layer <NUM>.

A source electrode <NUM> and a drain electrode <NUM>, which are formed of a conductive material, e.g., metal, are formed on the interlayer insulating layer <NUM>. In addition, the data line DL extends along the second direction. The power line PL and a second capacitor electrode (not shown) of the storage capacitor Cst may be formed on the interlayer insulating layer <NUM>. The source electrode <NUM> and the drain electrode <NUM> are spaced apart from each other with respect to the gate electrode <NUM> and respectively contact both sides of the semiconductor layer <NUM> through the first and second contact holes <NUM> and <NUM>.

The data line DL crosses the gate line GL to define the first and second pixels P1 and P2, and the power line PL is spaced apart from the data line DL. Alternatively, the power line PL may be formed on the same layer as the gate line GL to be spaced apart from the gate line GL and cross the data line DL.

The second capacitor electrode may be connected to the source electrode <NUM> and overlap the first capacitor electrode such that the first capacitor electrode, the second capacitor electrode and the interlayer insulating layer <NUM> therebetween constitute the storage capacitor Cst.

The semiconductor layer <NUM>, the gate electrode <NUM>, the source electrode <NUM> and the drain electrode <NUM> constitute the driving TFT Td. The gate electrode <NUM>, the source electrode <NUM> and the drain electrode <NUM> are positioned over the semiconductor layer <NUM>. Namely, the TFT Td has a coplanar structure. Alternatively, in the TFT Td, the gate electrode may be positioned under the semiconductor layer, and the source and drain electrodes may be positioned over the semiconductor layer such that the TFT Td may have an inverted staggered structure. In this instance, the semiconductor layer may include amorphous silicon.

As mentioned above, the switching TFT Ts may be disposed on the substrate <NUM>. The switching element may have substantially same structure as the driving TFT Td. The gate electrode of the driving TFT Td is connected to a drain electrode of the switching TFT Ts, and the source electrode <NUM> of the driving TFT Td is connected to the power line PL. In addition, the gate electrode and the source electrode of the switching TFT Ts are connected to the gate line GL and the data line DL, respectively.

A passivation layer <NUM>, which includes a drain contact hole <NUM> exposing the drain electrode <NUM> of the driving TFT Td, is formed to cover the driving TFT Td.

A first electrode <NUM>, which is connected to the drain electrode <NUM> of the driving TFT Td through the drain contact hole <NUM>, is separately formed on the passivation layer <NUM> in each of the first and second pixels P1 and P2. The first electrode <NUM> may be an anode and may be formed of a conductive material having a relatively high work function. For example, the first electrode <NUM> may be formed of a transparent conductive material such as indium-tin-oxide (ITO) or indiumzinc-oxide (IZO).

When the electroluminescent display device <NUM> is a top-emission type, a reflection electrode or a reflection layer may be formed under the first electrode <NUM>. For example, the reflection electrode or the reflection layer may be formed of aluminum-palladium-copper (APC) alloy.

A bank layer <NUM>, which covers edges of the first electrode <NUM>, is formed on the passivation layer <NUM>. The bank layer <NUM> has an opening OP corresponding to each of the first and second pixels P1 and P2 and the groove <NUM> between the first pixel P1 and the second pixel P2. The bank layer <NUM> surrounds and defines each of the first and second pixels P1 and P2, and an area of each of the first and second pixels P1 and P2 may correspond to an area of the opening OP or an area of the emitting layer <NUM> in the opening OP.

A center of the first electrode <NUM> is exposed through the opening OP, and the passivation layer <NUM> is exposed through the groove <NUM>.

The groove <NUM> has a depth Dg that is substantially equal to a thickness TB of the bank layer <NUM>. Alternatively, the groove <NUM> may be formed by removing a part of the bank layer <NUM> such that the depth of the groove <NUM> may be smaller than the thickness of the bank layer <NUM>. In addition, the groove <NUM> may be formed by removing the bank layer <NUM> and partially or completely removing the passivation layer <NUM> such that the depth of the groove <NUM> may be greater than the thickness of the bank layer <NUM>.

An emitting layer <NUM> is formed on the first electrode <NUM>. The emitting layer <NUM> may be formed by a solution process using a liquid phase emitting material. Namely, an emitting material solution with a solvent is coated and dried such that the emitting layer <NUM> is formed. For example, the solution process may be an inkjet coating process, a slit coating process, a spin coating process, a printing process or a drop coating process, but it is not limited thereto.

The emitting layer <NUM> may have a single-layered structure of an emitting material layer. Alternatively, to improve emitting efficiency, the emitting layer <NUM> may further include a hole injection layer and a hole transporting layer, which are sequentially stacked between the first electrode <NUM> and the emitting material layer, and an electron transporting layer and an electron injection layer sequentially between the emitting material layer and the second electrode <NUM>.

The emitting material layer may include an inorganic emitting material, e.g., a quantum dot, or an organic emitting material. The electroluminescent display device <NUM> of the present disclosure may be an organic light emitting display device (OLED) or a quantum dot light emitting display device (QLED).

After the solvent included in the emitting material solution for the emitting material layer is coated in the groove <NUM>, the solvent is dried and evaporated. As a result, after the emitting layer <NUM> is formed, there is no layer in the groove <NUM> such that the passivation layer <NUM> may be exposed through the groove <NUM>. Alternatively, when the emitting material solution is coated in the groove <NUM>, an auxiliary material pattern may be formed in the groove <NUM> and on the passivation layer <NUM>. The auxiliary material pattern described herein refers to solidified light emitting material remaining after solvents are vaporized.

In the electroluminescent display device <NUM>, solvent is coated in the groove <NUM> positioned between the first and second pixels P1 and P2. Hence, despite the second edge distance d2 between the first and second pixels P1 and P2 being greater than the first edge distance d1 between adjacent pixels P1, P2 between the same row, the solvent concentration in the surrounding air the first and second pixels P1 and P2 becomes uniform at different locations. As a result, the non-uniformity of thickness in the emitting layer <NUM> resulting from a difference in an edge distance between horizontally adjacent pixels and an edge distance between vertically adjacent pixels is prevented or reduced.

A second electrode <NUM> is formed over the substrate <NUM> including the emitting layer <NUM>. The second electrode <NUM> may be formed across an entire surface of the display area. The second electrode <NUM> may be a cathode and may be formed of a conductive material having a relatively low work function. For example, the second electrode <NUM> may be formed of aluminum (Al), magnesium (Mg) or Al-Mg alloy.

In the top-emission type electroluminescent display device <NUM>, the second electrode <NUM> may have a thin thickness such that the light from the emitting layer <NUM> may be transmitted through the second electrode <NUM>. On the other hand, in the bottom-emission type electroluminescent display device <NUM>, the second electrode <NUM> may serve as a reflection electrode.

The second electrode <NUM> contacts the emitting layer <NUM> in each of the first and second pixels P1 and P2 and the passivation layer <NUM> in the groove <NUM> between the first and second pixels P1 and P2. In addition, the second electrode <NUM> between adjacent first pixels P1 and between adjacent second pixels P2 may contact the bank layer <NUM>.

From the substrate <NUM>, the second electrode <NUM> has a first height H<NUM> in each of the first and second pixels P1 and P2, and a second height H<NUM> in the groove <NUM>. The second height H<NUM> is shorter than the first height H<NUM>. In addition, from the substrate <NUM>, the second electrode <NUM> has a third height H<NUM>, which is greater than the first height Hi, in a portion between adjacent first pixels P1 and/or between adjacent second pixels P2.

When the auxiliary material pattern is formed in the groove <NUM>, the second electrode <NUM> in the groove <NUM> contacts the auxiliary material pattern. In this instance, since the auxiliary material pattern does not contact the first electrode <NUM>, there is no emission from the auxiliary material pattern in the groove <NUM>. The first electrode <NUM>, the second electrode <NUM> facing the first electrode <NUM> and the emitting layer <NUM> therebetween constitute the light emitting diode D.

Although not shown, an encapsulation film or an encapsulation substrate may be formed on or over the light emitting diode D to prevent penetration of moisture into the light emitting diode D and protect the light emitting diode D. For example, the encapsulation film may include a first inorganic layer, an organic layer and a second inorganic layer sequentially stacked. In addition, a polarization plate may be disposed or attached on the encapsulation film to prevent or minimize an ambient light reflection. For example, the polarization plate may be a circular polarization plate.

In the electroluminescent display device <NUM> since the emitting layer <NUM> is formed by the solution process, the fabrication process is simplified and a large-sized display device can be fabricated.

In addition, since the solvent or the emitting material solution is coated in the groove <NUM> between the first and second pixels P1 and P2, which are spaced apart from each other by a relatively large edge distance, the thickness non-uniformity problem of the emitting layer <NUM> resulting from the solution process is prevented or minimized. Accordingly, the decrease problem of the display quality and the lifetime by the thickness non-uniformity of the emitting layer <NUM> is prevented or reduced.

However, in the electroluminescent display device <NUM> according to the first embodiment there may be still a thickness non-uniformity problem at a corner of the first and second pixels P1 and P2. An electroluminescent display device relieving or preventing this issue is described below with reference to <FIG>.

<FIG> is a schematic plane view of an electroluminescent display device according to a second inventive embodiment. As shown in <FIG>, in an electroluminescent display device <NUM>, a plurality of first pixels P1, a plurality of second pixels P2, a first groove <NUM> and a second groove <NUM> are arranged. The first pixels P1 are arranged in a first row along a first direction (e.g., horizontal direction), and the second pixels P2 are arranged in a second row in the same direction. The second pixels P2 are spaced apart from the first pixels P1 in a second direction (e.g., vertical direction) perpendicular to the first direction. The first and second grooves <NUM> and <NUM> extend along the first direction and are positioned between the first pixels P1 in the first row and the second pixels P2 in the second row. A pair of the grooves <NUM> and <NUM> is positioned between a pair of pixel rows.

The first groove <NUM> is positioned between a first horizontal pixel row, where the first pixels P1 are arranged, and a second horizontal pixel row, where the second pixels P2 are arranged, and the second groove <NUM> is positioned between the first groove <NUM> and the second horizontal pixel row.

The first groove <NUM> includes a first portion <NUM> extending in the first direction and second portions <NUM> bulging towards space between adjacent first pixels P1. The second portions <NUM> may be bumps extending from the first groove <NUM>. The second groove <NUM> includes a third portion <NUM> extending in the first direction and fourth portions <NUM> bulging toward space between adjacent second pixels P2. Accordingly, each of the first groove <NUM> and the second groove <NUM> has a first width (along a vertical direction) in a space between adjacent first pixels P1 (or adjacent second pixel P2), and the each of the first groove <NUM> and the second groove <NUM> has a second width in gaps between the first and second pixels P1 and P2. In other words, each of the first groove <NUM> and the second groove <NUM> has a different width along the length of the first and second grooves <NUM> and <NUM>. The first groove <NUM> and the second portions <NUM> may be collectively referred to herein as "indents. " In other words, the first groove <NUM> is positioned at a side of the first pixels P1 and includes the first portion <NUM> extending along the first direction and the second portions <NUM> bulging from the first portion <NUM>. The second groove <NUM> is positioned between the first groove <NUM> and a side of the second pixels P2 and includes the third portion <NUM> extending along the first direction and the fourth portions <NUM> bulging from the third portion <NUM>.

Each of the first and third portions <NUM> and <NUM> may has a linear bar shape and extend along a direction of the first and second horizontal pixel rows, i.e., the first direction. The second portion <NUM> protrudes from the first portion <NUM> toward the first pixel P1 (the first horizontal pixel row), and the fourth portion <NUM> protrudes from the third portion <NUM> toward the second pixel P2 (the second horizontal pixel row). The second and fourth portions <NUM> and <NUM> having semi-circular shapes are shown. However, there is no limitation in their shape. Each of the second portions <NUM> bulge into a gap between adjacent first pixels P1. Each of the fourth portions <NUM> bulge into a gap between adjacent second pixels P2.

Two of the adjacent first pixels P1 and two of the adjacent second pixels P2 are spaced apart from each other by a first edge distance d1, and the first pixel P1 and the second pixel P2 are spaced apart from each other by a second edge distance d2 that is greater than the first edge distance d1. The first and second grooves <NUM> and <NUM> are respectively spaced apart from the first and second pixels P1 and P2 by a third edge distance d3 substantially equal to the first edge distance d1.

The first and third portions <NUM> and <NUM> have the third edge distance d3 from the end of the first pixel P1 and the end of the second pixel P2, respectively, and the second and fourth portions <NUM> and <NUM> have the third edge distance d3 from the corner of the first pixel P1 and the corner of the second pixel P2, respectively.

In the electroluminescent display device <NUM>, each of the first and second pixels P1 and P2 has a round shape at a vertical end. When the first groove <NUM> includes the first portion <NUM> without the second portion <NUM>, the edge distance between the first groove <NUM> and the end of the first pixel P1 is different from the edge distance between the first groove <NUM> and the corner of the first pixel P1. Accordingly, the solvent concentration in the air at the end and the corner of the first pixel P1 becomes different such that there may be a thickness deviation of the emitting layer at the end and the corner of the first pixel P1. In addition, when the second groove <NUM> includes the third portion <NUM> without the fourth portion <NUM>, the edge distance between the second groove <NUM> and the end of the second pixel P2 is different from the edge distance between the second groove <NUM> and the corner of the second pixel P2 such that there may be a thickness deviation of the emitting layer at the end and the corner of the second pixel P2.

However, in the electroluminescent display device <NUM> of <FIG>, the first and second grooves <NUM> and <NUM> respectively include the second portions <NUM> and the fourth portions <NUM> such that the above problem is prevented. That is, since the edge distance between the end of the first pixel P1 and the first portion <NUM> of the first groove <NUM> is substantially equal to the edge distance between the corner of the first pixel P1 and the second portion <NUM> of the first groove <NUM>, the emitting layer may have a thickness uniformity at the end and the corner of the first pixel P1. In addition, since the edge distance between the end of the second pixel P2 and the third portion <NUM> of the second groove <NUM> is substantially equal to the edge distance between the corner of the second pixel P2 and the fourth portion <NUM> of the second groove <NUM>, the emitting layer may have a thickness uniformity at the end and the corner of the second pixel P2.

Moreover, since the edge distance between adjacent first pixels P1 and the edge distance between adjacent second pixels P2 are substantially equal to the third edge distance d3, which is an edge distance between the end of the first pixel P1 (second pixel P2) and the first portion <NUM> (third portion <NUM>) and an edge distance between the corner of the first pixel P1 (second pixel P2) and the second portion <NUM> (fourth portion <NUM>), the emitting layer in the first and second pixels P1 and P2 has a thickness uniformity regardless of the directions.

Further, a width of the second portion <NUM> may be smaller than an edge distance between adjacent first pixels P1, and a width of the fourth portion <NUM> may be smaller than an edge distance between adjacent second pixels P2. Accordingly, the solvent in the second and fourth portions <NUM> and <NUM> does not affect the evaporation condition at the end (central end) of the first and second pixels P1 and P2.

<FIG> is a cross-sectional view taken along the line VIII-VIII of <FIG> is a cross-sectional view taken along the line IX-IX of <FIG>. As shown in <FIG>, the electroluminescent display device <NUM> according to the second embodiment includes a substrate <NUM>, where the first pixels P1 adjacent along the first direction and the second pixels P2 adjacent to the first pixel P1 along the second direction are defined, the driving TFT Td on or over the substrate <NUM>, the light emitting diode D connected to the driving TFT Td and the first and second grooves <NUM> and <NUM> along the first direction and between the first and second pixels P1 and P2.

The substrate <NUM> may be a glass substrate or a plastic substrate. A semiconductor layer <NUM> is formed on the substrate <NUM>. The semiconductor layer <NUM> may be formed of an oxide semiconductor material or a poly-silicon. A gate insulating layer <NUM> is formed on the semiconductor layer <NUM>. The gate insulating layer <NUM> may be formed of an inorganic insulating material such as silicon oxide or silicon nitride. A gate electrode <NUM>, which is formed of a conductive material, e.g., metal, is formed on the gate insulating layer <NUM> to correspond to a center of the semiconductor layer <NUM>. The gate line GL may extend along the first direction, and the first capacitor electrode may be connected to the gate electrode <NUM>.

An interlayer insulating layer <NUM>, which is formed of an insulating material, is formed on an entire surface of the substrate <NUM> including the gate electrode <NUM>. The interlayer insulating layer <NUM> may be formed of an inorganic insulating material, e.g., silicon oxide or silicon nitride, or an organic insulating material, e.g., benzocyclobutene or photo-acryl.

A source electrode <NUM> and a drain electrode <NUM>, which are formed of a conductive material, e.g., metal, are formed on the interlayer insulating layer <NUM>. In addition, the data line DL along the second direction, the power line PL and a second capacitor electrode (not shown) of the storage capacitor Cst may be formed on the interlayer insulating layer <NUM>.

The source electrode <NUM> and the drain electrode <NUM> are spaced apart from each other with respect to the gate electrode <NUM> and respectively contact both sides of the semiconductor layer <NUM> through the first and second contact holes <NUM> and <NUM>.

The data line DL crosses the gate line GL to define the first and second pixels P1 and P2, and the power line PL is spaced apart from the data line DL.

A bank layer <NUM>, which covers edges of the first electrode <NUM>, is formed on the passivation layer <NUM>. The bank layer <NUM> has an opening OP corresponding to each of the first and second pixels P1 and P2 and the first and second grooves <NUM> and <NUM> between the first pixel P1 and the second pixel P2.

The bank layer <NUM> surrounds each of the first and second pixels P1 and P2, and an area of each of the first and second pixels P1 and P2 may correspond to an area of the opening OP or an area of the emitting layer <NUM> in the opening OP.

A center of the first electrode <NUM> is exposed through the opening OP, and the passivation layer <NUM> is exposed through the first and second grooves <NUM> and <NUM>.

The first groove <NUM> includes the first portion <NUM> corresponding to the first horizontal pixel row and the second portion <NUM> corresponding to a space between adjacent first pixels P1. The second groove <NUM> includes the third portion <NUM> corresponding to the second horizontal pixel row and the fourth portion <NUM> corresponding to a space between adjacent second pixels P2.

Each of the first and second grooves <NUM> and <NUM> has a depth Hg2 being substantially equal to a thickness TB2 of the bank layer <NUM>. Alternatively, the first and second grooves <NUM> and <NUM> may be formed by removing a part of the bank layer <NUM> such that the depth of the first and second grooves <NUM> and <NUM> may be smaller than the thickness of the bank layer <NUM>. In addition, the first and second grooves <NUM> and <NUM> may be formed by removing the bank layer <NUM> and partially or completely removing the passivation layer <NUM> such that the depth of the first and second grooves <NUM> and <NUM> may be greater than the thickness of the bank layer <NUM>.

The emitting material layer may include an inorganic emitting material, e.g., a quantum dot, or an organic emitting material. Namely, the electroluminescent display device <NUM> of the present disclosure may be an organic light emitting display device (OLED) or a quantum dot light emitting display device (QLED). The emitting material solution is coated in the first and second grooves <NUM> and <NUM> such that first and second auxiliary material patterns <NUM> and <NUM> are respectively formed in the first and second grooves <NUM> and <NUM>. Alternatively, when the solvent, which is included in the emitting material solution for the emitting material layer, is coated in the first and second grooves <NUM> and <NUM>, there is no layer in the first and second grooves <NUM> and <NUM> such that the passivation layer <NUM> may be exposed through the first and second grooves <NUM> and <NUM> after the emitting material layer is formed.

In the electroluminescent display device <NUM>, the solvent is added into the first and second grooves <NUM> and <NUM> positioned between the first and second pixels P1 and P2. The first and second pixels P1 and P2 are separated by the second edge distance d2 greater than the first edge distance d1 between adjacent pixels P1/P2 of the same line. When the solvent in the grooves <NUM>, <NUM> evaporate, the solvent concentration in the surrounding air around the first and second pixels P1 and P2 is uniformed regardless of the directions.

In addition, since the first and second grooves <NUM> and <NUM> respectively include the second and fourth portions <NUM> and <NUM> corresponding to a space between adjacent first pixels P1 and a space between adjacent second pixels P2, respectively, the thickness deviation of the emitting layer <NUM> at the end and the corner of the first and second pixels P1 and P2 is prevented.

As a result, the thickness non-uniformity problem of the emitting layer <NUM>, which results from a difference in an edge distance between horizontally adjacent pixels and an edge distance between vertically adjacent pixels and a round shape of the first and second pixels P1 and P2, is prevented or minimized.

A second electrode <NUM> is formed over the substrate <NUM> including the emitting layer <NUM> and the first and second auxiliary material patterns <NUM> and <NUM>. The second electrode <NUM> may be positioned at an entire surface of the display area. The second electrode <NUM> may be a cathode and may be formed of a conductive material having a relatively low work function. For example, the second electrode <NUM> may be formed of aluminum (Al), magnesium (Mg) or Al-Mg alloy.

In the top-emission type electroluminescent display device <NUM>, the second electrode <NUM> may be thin such that the light from the emitting layer <NUM> may be transmitted through the second electrode <NUM>. On the other hand, in the bottom-emission type electroluminescent display device <NUM>, the second electrode <NUM> may serve as a reflection electrode.

The second electrode <NUM> contacts the emitting layer <NUM> in each of the first and second pixels P1 and P2 and the first and second auxiliary material patterns <NUM> and <NUM> in the first and second grooves <NUM> and <NUM> between the first and second pixels P1 and P2. In addition, the second electrode <NUM> between adjacent first pixels P1 and between adjacent second pixels P2 may contact the bank layer <NUM>.

From the substrate <NUM>, the second electrode <NUM> has a first height in each of the first and second pixels P1 and P2 and a second height, which is substantially equal to the first height, in the first and second grooves <NUM> and <NUM>. In addition, from the substrate <NUM>, the second electrode <NUM> has a third height, which is greater than the first height, in a portion between adjacent first pixels P1 and/or between adjacent second pixels P2.

The second electrode <NUM> in the first and second grooves <NUM> and <NUM> contacts the first and second auxiliary material patterns <NUM> and <NUM>. However, since the first and second auxiliary material patterns <NUM> and <NUM> do not contact the first electrode <NUM>, there is no emission from the first and second auxiliary material patterns <NUM> and <NUM> in the first and second grooves <NUM> and <NUM>.

The first electrode <NUM>, the second electrode <NUM> facing the first electrode <NUM> and the emitting layer <NUM> therebetween constitute the light emitting diode D.

Although not shown, an encapsulation film or an encapsulation substrate may be formed on or over the light emitting diode D to prevent penetration of moisture into the light emitting diode D and protect the light emitting diode D. In addition, a polarization plate may be disposed or attached on the encapsulation film to prevent or minimize an ambient light reflection. For example, the polarization plate may be a circular polarization plate.

In the electroluminescent display device <NUM>, since the emitting layer <NUM> is formed by the solution process, the fabrication process is simplified and a large-size display device is provided.

In addition, since the solvent or the emitting material solution is coated in the first groove <NUM>, which includes the first portion <NUM> of a bar shape and the second portion <NUM> protruding from the first portion <NUM>, and the second groove <NUM>, which includes the third portion <NUM> of a bar shape and the fourth portion <NUM> protruding from the third portion <NUM>, between the first and second pixels P1 and P2, which are spaced apart from each other by a relatively large edge distance, the thickness non-uniformity problem of the emitting layer <NUM> resulting from the solution process is prevented or minimized. Accordingly, the decrease problem of the display quality and the lifetime by the thickness non-uniformity of the emitting layer <NUM> is prevented or minimized.

<FIG> is a schematic plane view of an electroluminescent display device according to a third inventive embodiment. As shown in <FIG>, in an electroluminescent display device <NUM>, a plurality of first pixels P1, a plurality of second pixels P2 and a groove <NUM> are arranged. The first pixels P1 are arranged in a first row along a first direction (e.g., horizontal direction), and the second pixels P2 are arranged in a second row. The second pixels P2 are spaced apart from the first pixels P1 in a second direction (e.g., vertical direction) perpendicular to the first direction. The groove <NUM> extends along the first direction and is positioned between the first pixels P1 in the first row and the second pixels P2 in the second row.

The groove <NUM> is positioned between a first horizontal pixel row, where the first pixels P1 are arranged, and a second horizontal pixel row, where the second pixels P2 are arranged. The groove <NUM> includes a first portion <NUM> placed between the first and second pixels P1 and P2 and extending in the first direction, second portions <NUM> bulging towards space between adjacent first pixels P1, and third portions <NUM> bulging towards space between adjacent second pixels P2. Accordingly, the groove <NUM> has a first width (along a vertical direction) in a space between adjacent first pixels P1 (or adjacent second pixel P2), and the groove <NUM> has a second width in gaps between the first and second pixels P1 and P2. In other words, the groove <NUM> has a different width along the length of the groove <NUM>. The groove <NUM>, the second portions <NUM> and the third portions <NUM> may be collectively be referred to as "indents.

The first portion <NUM> may has a linear bar shape. The second portions <NUM> protrude from the first portion <NUM> toward the first pixel P1 (the first horizontal pixel row), and the third portions <NUM> protrude from the first portion <NUM> toward the second pixel P2 (the second horizontal pixel row). Although <FIG> shows the first portion <NUM> having a bar shape and the second and third portions <NUM> and <NUM> having semi-circular shapes, this is merely for illustration.

Two of the adjacent first pixels P1 and two of the adjacent second pixels P2 are spaced apart from each other by a first edge distance d1, and the first pixel P1 and the second pixel P2 are spaced apart from each other by a second edge distance d2 greater than the first edge distance d1. The groove <NUM> is spaced apart from the first and second pixels P1 and P2 by a third edge distance d3 substantially equal to the first edge distance d1. The first portion <NUM> has the third edge distance d3 from the end of the first pixel P1 and the end of the second pixel P2, and the second and third portions <NUM> and <NUM> have the third edge distance d3 from the corner of the first pixel P1 and the corner of the second pixel P2, respectively. Accordingly, in the electroluminescent display device <NUM> including the first and second pixels P1 and P2, which has a rounded-end shape, the emitting layer has a uniform thickness at the end and the corner of the first and second pixels P1 and P2.

Moreover, since the edge distance between adjacent first pixels P1 and the edge distance between adjacent second pixels P2 are substantially equal to the third edge distance d3, which is an edge distance between the end of the first pixel P1 (second pixel P2) and the first portion <NUM> and an edge distance between the corner of the first pixel P1 (second pixel P2) and the second portion <NUM> (third portion <NUM>), the emitting layer in the first and second pixels P1 and P2 has a thickness uniformity regardless of the directions.

Further, a width of the second portion <NUM> may be smaller than an edge distance between adjacent first pixels P1, and a width of the third portion <NUM> may be smaller than an edge distance between adjacent second pixels P2. Accordingly, the solvent in the second and third portions <NUM> and <NUM> does not affect the evaporation condition at the end (central end) of the first and second pixels P1 and P2.

<FIG> is a cross-sectional view taken along the line XI-XI of <FIG> is a cross-sectional view taken along the line XII-XII of <FIG>. As shown in <FIG>, the electroluminescent display device <NUM> according to the third embodiment includes a substrate <NUM>, where the first pixels P1 adjacent along the first direction and the second pixels P2 adjacent to the first pixel P1 along the second direction are defined, the driving TFT Td on or over the substrate <NUM>, the light emitting diode D connected to the driving TFT Td and the groove <NUM> along the first direction and between the first and second pixels P1 and P2.

The gate line GL and the data line DL cross each other to define the first and second pixels P1 and P2, and the driving TFT Td is connected to the switching TFT Ts. In addition, the storage capacitor Cst may be formed in each of the first and second pixels P1 and P2. The substrate <NUM> may be a glass substrate or a plastic substrate. A semiconductor layer <NUM> is formed on the substrate <NUM>. The semiconductor layer <NUM> may be formed of an oxide semiconductor material or a poly-silicon. A gate insulating layer <NUM> is formed on the semiconductor layer <NUM>. The gate insulating layer <NUM> may be formed of an inorganic insulating material such as silicon oxide or silicon nitri de.

A gate electrode <NUM>, which is formed of a conductive material, e.g., metal, is formed on the gate insulating layer <NUM> to correspond to a center of the semiconductor layer <NUM>. The gate line GL may extend along the first direction, and the first capacitor electrode may be connected to the gate electrode <NUM>.

A first electrode <NUM>, which is connected to the drain electrode <NUM> of the driving TFT Td through the drain contact hole <NUM>, is separately formed on the passivation layer <NUM> in each of the first and second pixels P1 and P2. The first electrode <NUM> may be an anode and may be formed of a conductive material having a relatively high work function. For example, the first electrode <NUM> may be formed of a transparent conductive material such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO).

A bank layer <NUM>, which covers edges of the first electrode <NUM>, is formed on the passivation layer <NUM>. The bank layer <NUM> has an opening OP corresponding to each of the first and second pixels P1 and P2 and the groove <NUM> between the first pixel P1 and the second pixel P2.

The groove <NUM> includes the first portion <NUM> between the first and second pixels P1 and P2, the second portion <NUM> corresponding to a space between adjacent first pixels P1 and the third portion <NUM> corresponding to a space between adjacent second pixels P2.

The first portion <NUM> has the third edge distance d3 from the end of the first pixel P1 and the end of the second pixel P2, and the second and third portions <NUM> and <NUM> have the third edge distance d3 from the corner of the first pixel P1 and the corner of the second pixel P2, respectively.

The groove <NUM> has a depth being substantially equal to a thickness of the bank layer <NUM>. Alternatively, the groove <NUM> may be formed by removing a part of the bank layer <NUM> such that the depth of the groove <NUM> may be smaller than the thickness of the bank layer <NUM>. In addition, the groove <NUM> may be formed by removing the bank layer <NUM> and partially or completely removing the passivation layer <NUM> such that the depth of the groove <NUM> may be greater than the thickness of the bank layer <NUM>.

The emitting material layer may include an inorganic emitting material, e.g., a quantum dot, or an organic emitting material. Namely, the electroluminescent display device <NUM> of the present disclosure may be an organic light emitting display device (OLED) or a quantum dot light emitting display device (QLED).

The emitting material solution is coated in the groove <NUM> such that an auxiliary material pattern <NUM> is formed in the groove <NUM>.

Alternatively, when the solvent, which is included in the emitting material solution for the emitting material layer, is coated in the groove <NUM>, there is no layer in the groove <NUM> such that the passivation layer <NUM> may be exposed through the groove <NUM> after the emitting material layer is formed.

In the electroluminescent display device <NUM>, the solvent is placed in the groove <NUM> positioned between the first and second pixels P1 and P2. The first and second pixels P1 and P2 are adjacent to each other by the second edge distance d2 greater than the first edge distance d1 between adjacent pixels P1/P2 in the same row. Therefore, when the solvent in the groove <NUM> evaporates, the solvent concentration in the surrounding air of the first and second pixels P1 and P2 remains uniform regardless of the directions. In addition, since the groove <NUM> includes the second and third portions <NUM> and <NUM>, the thickness deviation of the emitting layer <NUM> at the end and the corner of the first and second pixels P1 and P2 is reduced or prevented. As a result, the thickness non-uniformity problem of the emitting layer <NUM>, which results from a difference in an edge distance between horizontally adjacent pixels and an between vertically adjacent pixels and a round shape of the first and second pixels P1 and P2, is prevented or minimized.

A second electrode <NUM> is formed over the substrate <NUM> including the emitting layer <NUM> and auxiliary material pattern <NUM>. The second electrode <NUM> may be positioned at an entire surface of the display area. The second electrode <NUM> may be a cathode and may be formed of a conductive material having a relatively low work function. For example, the second electrode <NUM> may be formed of aluminum (Al), magnesium (Mg) or Al-Mg alloy.

The second electrode <NUM> contacts the emitting layer <NUM> in each of the first and second pixels P1 and P2 and the auxiliary material pattern <NUM> in the groove <NUM> between the first and second pixels P1 and P2. In addition, the second electrode <NUM> between adjacent first pixels P1 and between adjacent second pixels P2 may contact the bank layer <NUM>.

From the substrate <NUM>, the second electrode <NUM> has a first height in each of the first and second pixels P1 and P2 and a second height, which is substantially equal to the first height, in the groove <NUM>. In addition, from the substrate <NUM>, the second electrode <NUM> has a third height, which is greater than the first height, in a portion between adjacent first pixels P1 and/or between adjacent second pixels P2.

The second electrode <NUM> in the groove <NUM> contacts the auxiliary material pattern <NUM>. However, since the auxiliary material pattern <NUM> does not contact the first electrode <NUM>, there is no emission from the auxiliary material pattern <NUM> in the groove <NUM>.

In addition, since the solvent or the emitting material solution is coated in the groove <NUM>, which includes the first portion <NUM> of a bar shape and the second and third portions <NUM> and <NUM> respectively protruding from the first portion <NUM>, between the first and second pixels P1 and P2, which are spaced apart from each other by a relatively large edge distance, the thickness non-uniformity problem of the emitting layer <NUM> resulting from the solution process is prevented or minimized. Accordingly, the decrease problem of the display quality and the lifetime by the thickness non-uniformity of the emitting layer <NUM> is prevented or minimized.

<FIG> is a schematic plane view of an electroluminescent display device according to a fourth inventive embodiment. As shown in <FIG>, in an electroluminescent display device <NUM>, a plurality of first pixels P1, a plurality of second pixels P2, a first indent <NUM> and a second indent <NUM> are arranged. The first pixels P1 are arranged in a first row along a first direction, and the second pixels P2 are arranged in a second row. The second pixels P2 are spaced apart from the first pixels P1 in a second direction being perpendicular to the first direction. The first and second indents <NUM> and <NUM> extend along the first direction and are positioned between the first pixels P1 in the first row and the second pixels P2 in the second row. Namely, a pair of the grooves <NUM> and <NUM> is positioned between a pair of pixel rows.

The first indent <NUM> is positioned between a first horizontal pixel row, where the first pixels P1 are arranged, and a second horizontal pixel row, where the second pixels P2 are arranged, and the second indent <NUM> is positioned between the first indent480 and the second horizontal pixel row.

The first indent <NUM> includes a groove <NUM> extending in the first direction. The first indent <NUM> also includes holes <NUM> formed separately from the groove <NUM> and also holds emitting material solution in conjunction with the groove <NUM>. Each of the holes <NUM> are placed between the groove <NUM> and a gap of adjacent first pixels P1. The second indent <NUM> includes a second groove <NUM> extending in the first direction. The second indent <NUM> also includes holes <NUM> formed between the second groove <NUM> and gaps between the adjacent second pixels P2.

Each of the grooves <NUM> and <NUM> may has a linear bar shape and extend along a direction of the first and second horizontal pixel rows, i.e., the first direction. However, there is no limitation in their shape.

Two of the adjacent first pixels P1 and two of the adjacent second pixels P2 are spaced apart from each other by a first edge distance d1, and the first pixel P1 and the second pixel P2 are spaced apart from each other by a second edge distance d2 greater than the first edge distance d1. The first and second grooves <NUM> and <NUM> are respectively spaced apart from the first and second pixels P1 and P2 by a third edge distance d3 substantially equal to the first edge distance d1.

The first and second indents <NUM> and <NUM> have the third edge distance d3 from the end of the first pixel P1 and the end of the second pixel P2, respectively, and the holes <NUM> and <NUM> have the third edge distance d3 from the corner of the first pixel P1 and the corner of the second pixel P2, respectively. Accordingly, in the electroluminescent display device <NUM> including the first and second pixels P1 and P2, which has a rounded-end shape, the emitting layer has a uniform thickness at the end and the corner of the first and second pixels P1 and P2.

Moreover, since the first edge distance between adjacent first pixels P1 and between adjacent second pixels P2 is substantially equal to the third edge distance d3, which is an edge distance between the end of the first pixel P1 (second pixel P2) and the first groove <NUM> (the second groove <NUM>) and an edge distance between the corner of the first pixel P1 (second pixel P2) and the second portion <NUM> (fourth portion <NUM>), the emitting layer in the first and second pixels P1 and P2 has a thickness uniformity regardless of the directions.

Further, a width of the second portion <NUM> may be smaller than an edge distance between adjacent first pixels P1, and a width of the holes <NUM> may be smaller than an edge distance between adjacent second pixels P2. Accordingly, the solvent in the holes <NUM> and <NUM> does not affect the evaporation condition at the end (central end) of the first and second pixels P1 and P2.

<FIG> is a schematic plane view of an electroluminescent display device according to a fifth inventive embodiment. As shown in <FIG>, in an electroluminescent display device <NUM>, a plurality of first pixels P1, a plurality of second pixels P2 and an indent <NUM> are arranged. The first pixels P1 are arranged in a first row along a first direction, and the second pixels P2 are arranged in a second row. The second pixels P2 are spaced apart from the first pixels P1 in a second direction being perpendicular to the first direction. The groove <NUM> of the indent <NUM> extends along the first direction and is positioned between the first pixels P1 in the first row and the second pixels P2 in the second row.

The indent <NUM> is positioned between a first horizontal pixel row, where the first pixels P1 are arranged, and a second horizontal pixel row, where the second pixels P2 are arranged. The indent <NUM> includes a groove <NUM> between the first and second pixels P1 and P2, holes <NUM> corresponding to a space between adjacent first pixels P1 and holes <NUM> corresponding to a space between adjacent second pixels P2.

The indent <NUM> may have a linear bar shape and extend along a direction of the first and second horizontal pixel rows, i.e., the first direction. Holes <NUM> are spaced apart from the groove <NUM> toward the first pixel P1 (the first horizontal pixel row), and the third portion <NUM> is spaced apart from the groove <NUM> toward the second pixel P2 (the second horizontal pixel row).

Holes <NUM> may be closer to the groove <NUM> than the first pixel P1, and holes <NUM> may be closer to the groove <NUM> than the second pixel P2.

The groove <NUM> has a bar shape and the holes <NUM> and <NUM> have a semi-circular shape are shown. However, there is no limitation in their shape.

Adjacent two of the first pixels P1 and adjacent two of the second pixels P2 are spaced apart from each other by a first edge distance d1, and the first pixel P1 and the second pixel P2 are spaced apart from each other by a second edge distance d2 being greater than the first edge distance d1. The groove <NUM> is spaced apart from the first and second pixels P1 and P2 by a third edge distance d3 substantially equal to the first edge distance d1.

The groove <NUM> has the third edge distance d3 from the end of the first pixel P1 and the end of the second pixel P2, and the holes <NUM> and <NUM> have the third edge distance d3 from the corner of the first pixel P1 and the corner of the second pixel P2, respectively. Accordingly, in the electroluminescent display device <NUM> including the first and second pixels P1 and P2, which has a rounded-end shape, the emitting layer has a uniform thickness at the end and the corner of the first and second pixels P1 and P2.

Moreover, since the edge distance between adjacent first pixels P1 and the edge distance between adjacent second pixels P2 are substantially equal to the third edge distance d3, which is an edge distance between the end of the first pixel P1 (second pixel P2) and the groove 582and an edge distance between the corner of the first pixel P1 (second pixel P2) and the holes <NUM>, <NUM>, the emitting layer in the first and second pixels P1 and P2 has a thickness uniformity regardless of the directions.

Further, a width of the holes <NUM> may be smaller than an edge distance between adjacent first pixels P <NUM>, and a width of the holes <NUM> may be smaller than an edge distance between adjacent second pixels P2. Accordingly, the solvent in the holes <NUM> and <NUM> does not affect the evaporation condition at the end (central end) of the first and second pixels P1 and P2.

The thickness (Ex) of the emitting layer in the electroluminescent display device <NUM> (of <FIG>) according to the second embodiment and the thickness (Ref) of the emitting layer in the related art electroluminescent display device, where there is no groove, are measured and listed in Tables <NUM> and <NUM>. In addition, the thickness profiles of the emitting layers in a minor axis and a major axis of the pixel are shown in <FIG>, respectively.

In Tables <NUM> and <NUM>, the term "Avg" is an average thickness of the emitting layer, and the term "dC" is a thickness at a center of the emitting layer. The terms "d+<NUM>" and "d+<NUM>" is a difference between the "dC" thickness and a thickness at a portion by a distance ("<NUM>" or "<NUM>") from an edge (d) toward the center.

Claim 1:
An electroluminescent display device, comprising:
a first pixel (P1) on a substrate (<NUM>);
another first pixel (P1) on the substrate (<NUM>), the other first pixel (P1) is separated from the first pixel (P1) in a first direction, wherein the first pixel (P1) and the other first pixel (P1) are arranged in a first horizontal pixel row;
a second pixel (P2) on the substrate (<NUM>), the second pixel (P2) is separated from the first pixel (P1) in a second direction perpendicular to the first direction, wherein the second pixel (P2) is arranged in a second horizontal pixel row, and wherein the first pixel (P1) and the second pixel (P2) are vertically adjacent in a vertical pixel column;
a light emitting diode (D) in each of the first and second pixels (P1, P2);
a bank layer (<NUM>) having openings defining the first pixel (P1), the other first pixel (P1) and the second pixel (P2); and
at least one indent (<NUM>, <NUM>, <NUM>) between the first pixel (P1) and the second pixel (P2) and including a first portion (<NUM>, <NUM>, <NUM>), the first portion (<NUM>, <NUM>, <NUM>) extends in parallel to the first and second horizontal pixel rows,
wherein the indent (<NUM>, <NUM>, <NUM>) is formed in a top surface of the bank layer (<NUM>), and
wherein third edge distances (d3) from the indent (<NUM>, <NUM>, <NUM>) to the first horizontal pixel row and the second horizontal pixel row are same, and
characterized in that the third edge distances (d3) from the indent (<NUM>, <NUM>, <NUM>) to the first horizontal pixel row and the second horizontal pixel row and a first edge distance (d1) from the first pixel (P1) to the other first pixel (P1) are equal, and
wherein the third edge distances (d3) are distances in the second direction between an edge of the indent (<NUM>, <NUM>, <NUM>) closest to edges of the pixels of a respective one of the first horizontal pixel row and the second horizontal pixel row and said edges of the pixels.