KR102546420B1 - Electroluminescent Display Device and Method of Fabricating the same - Google Patents

Abstract

[0001] The present invention relates to an electroluminescent display device, which includes: a substrate having a major axis and a minor axis and defining a plurality of pixel regions that are longer than the distance in the direction of the major axis and in the direction of the minor axis; A passivation film on the top, a first electrode positioned in each pixel area on the passivation film, a bank between adjacent pixel areas covering the edge of the first electrode, a light emitting layer on top of the first electrode in the bank, and a second electrode on top of the light emitting layer wherein the passivation layer has a groove between adjacent pixel regions in a short-axis direction, and a first height of a bank between pixel regions adjacent in a short-axis direction from an upper surface of the first electrode is between pixel regions adjacent in a long-axis direction from the upper surface of the first electrode lower than the second height of the bank of
Accordingly, image quality may be improved by forming a light emitting layer having a uniform thickness through a solution process by varying the height of the bank in the direction of the major axis and the minor axis of the pixel region.

Description

Electroluminescent Display Device and Method of Fabricating the Same}

The present invention relates to an electroluminescent display device, and more particularly, to a large-area, high-resolution electroluminescence display device capable of providing uniform luminance and a manufacturing method thereof.

Recently, a flat panel display having excellent characteristics such as thinness, light weight, and low power consumption has been widely developed and applied to various fields.

Among flat panel display devices, an organic light emitting diode display device (OLED display device), also called an electroluminescent display device, has a light emitting layer formed between a cathode as an electron injection electrode and an anode as a hole injection electrode. Electrons and holes form excitons by injecting charge into them, and then these excitons undergo radiative recombination to emit light. Such an electroluminescent display device can be formed on a flexible substrate such as plastic, and has a high contrast ratio because it is a self-luminous type and has a response time of several microseconds (μs), so it is easy to implement moving images. It is easy, has no viewing angle limitation, is stable even at low temperatures, and can be driven with a relatively low voltage of 5V to 15V DC, so it has the advantage of easy manufacturing and design of a driving circuit.

1 is a diagram showing the structure of a general electroluminescence display in a band diagram.

As shown in FIG. 1, in the electroluminescent display device, a light emitting material layer 4 is positioned between an anode 1 as an anode and a cathode 7 as a cathode. In order to inject holes from the anode 1 and electrons from the cathode 7 into the light emitting material layer 4, between the anode 1 and the light emitting material layer 4 and between the cathode 7 and the light emitting material layer 4 ), a hole transporting layer (HTL) 3 and an electron transporting layer (ETL) 5 are respectively positioned between them. At this time, in order to inject holes and electrons more efficiently, a hole injection layer (HIL) 2 is provided between the anode 1 and the hole transport layer 3, and between the electron transport layer 5 and the cathode 7. Further includes an electron injection layer (EIL) 6.

In the electroluminescent display device having such a structure, holes (+) injected from the anode 1 through the hole injection layer 2 and the hole transport layer 3 into the light emitting material layer 4 and electrons from the cathode 7 Electrons (-) injected into the light emitting material layer 4 through the injection layer 6 and the electron transport layer 5 are combined to form excitons 8, and the light emitting material layer 4 from the excitons 8 It emits light of a color corresponding to the band gap of .

The light emitting material layer 4, the hole injection layer 2, the hole transport layer 3, the electron transport layer 5, and the electron injection layer 6 of the electroluminescent display device are formed by using a fine metal mask. It is formed by a vacuum thermal evaporation method that selectively deposits an organic light emitting material.

However, such a deposition process increases manufacturing cost due to the provision of a mask, and is difficult to apply to a large-area and high-resolution display device due to variations in mask manufacturing, sagging, and shadow effects.

To solve this problem, a method of forming a light emitting material layer by a solution process has been proposed. In the solution process, a bank surrounding a pixel area is formed, and a solution containing a light emitting material is dropped on the pixel area in the bank by scanning a nozzle of an injection device in a certain direction, and then dried to emit light. form a material layer.

However, in the method of forming the light emitting material layer by such a solution process, the evaporation of the solvent is not uniform during the drying process of the solution, so that the light emitting material layer formed in the pixel area has a non-uniform thickness. That is, the light emitting material layer may have an asymmetrical U-shape in which one side is rapidly thicker than the other side, or a W-shape in which the central thickness is thicker than the edge.

A light emitting diode including a light emitting material layer having a non-uniform thickness emits non-uniform light, and accordingly, luminance of the electroluminescent display device is non-uniform, resulting in deterioration in image quality.

SUMMARY OF THE INVENTION The present invention is intended to solve problems of increased manufacturing cost and area and resolution limitations of an electroluminescent display device by a deposition process.

In addition, the present invention is to solve the luminance uniformity problem of the electroluminescent display device.

In order to achieve the above object, an electroluminescent display device according to the present invention includes a first pixel area, and second and third pixel areas adjacent to the first pixel area along first and second directions, respectively, are defined. a substrate; an insulating layer positioned on the substrate and including a groove between the first and second pixel regions; first electrodes disposed on the insulating layer and corresponding to each of the first to third pixel regions; a bank covering an edge of the first electrode and positioned between the first and second pixel areas and between the first and third pixel areas; a light emitting layer on the first electrode; The bank including a second electrode on the light emitting layer, positioned between the first pixel area and the second pixel area, has a first height from the first electrode, and is positioned between the first pixel area and the third pixel area. The bank located has a second height smaller than the first height from the first electrode.

Further, the electroluminescent display device of the present invention includes: a substrate defining a first pixel region and second and third pixel regions respectively adjacent to the first pixel region along first and second directions; a first electrode corresponding to each of the first to third pixel regions; a bank covering an edge of the first electrode and positioned between the first and second pixel areas and between the first and third pixel areas; a light emitting layer on the first electrode; A second electrode is included on the emission layer, and a bottom surface of the bank is located lower than a bottom surface of the first electrode between the first pixel area and the second pixel area.

In addition, in the manufacturing method of the electroluminescent display device of the present invention, a first pixel region, and second and third pixel regions adjacent to the first pixel region along the first and second directions, respectively, are defined on an upper portion of a substrate that is insulated. forming a layer; forming a first electrode on the insulating layer corresponding to each of the first to third pixel regions; etching a portion of the insulating layer to form a groove between the first and second pixel regions; forming a bank covering an edge of the first electrode and positioned between the first and second pixel areas and between the first and third pixel areas; forming a light emitting layer on the first electrode; and forming a second electrode on the light emitting layer, wherein the bank positioned between the first pixel area and the second pixel area has a first height from the first electrode, and the first pixel area and the second electrode have The bank located between the three pixel areas has a second height smaller than the first height from the first electrode.

In the present invention, by forming the light emitting layer of the light emitting diode through a solution process, manufacturing costs can be reduced and a large area and high resolution electroluminescent display can be provided.

In addition, image quality can be improved by forming a light emitting layer having a uniform thickness by varying the heights of the banks in the direction of the major axis and the minor axis of the pixel region.

In addition, it is possible to prevent an increase in power consumption and a decrease in lifetime caused by the light emitting layer having a non-uniform thickness.

1 is a diagram showing the structure of a general electroluminescence display in a band diagram.
2 is a circuit diagram showing one pixel area of an electroluminescent display device according to an exemplary embodiment of the present invention.
3 is a cross-sectional view of an electroluminescent display device according to an embodiment of the present invention.
4 is a schematic plan view of an electroluminescent display device according to a first embodiment of the present invention.
FIG. 5 is a schematic cross-sectional view of the electroluminescent display device according to the first embodiment of the present invention, corresponding to the line VV of FIG. 4 .
FIG. 6 is a schematic cross-sectional view of the electroluminescent display device according to the first embodiment of the present invention, corresponding to the line VI-VI of FIG. 4 .
FIG. 7 is a schematic cross-sectional view of the electroluminescent display device according to the first embodiment of the present invention, corresponding to the line VII-VII of FIG. 4 .
8 is a schematic plan view of another example of an electroluminescent display device according to the first embodiment of the present invention.
9 is a schematic cross-sectional view of an electroluminescent display device according to a second embodiment of the present invention.
10 is a schematic cross-sectional view of an electroluminescent display device according to a third embodiment of the present invention.
11 is a schematic cross-sectional view of an electroluminescent display device according to a fourth embodiment of the present invention.
12 is a schematic cross-sectional view of an electroluminescent display device according to a fifth embodiment of the present invention.
13A to 13C are schematic cross-sectional views showing manufacturing processes for a part of an electroluminescent display device according to a fifth embodiment of the present invention.
14 is a schematic plan view of an electroluminescent display device according to a sixth embodiment of the present invention.
FIG. 15 is a schematic cross-sectional view of an electroluminescent display device according to a sixth embodiment of the present invention, corresponding to the line XV-XV of FIG. 14 .
FIG. 16 is a schematic cross-sectional view of an electroluminescent display device according to a sixth embodiment of the present invention corresponding to line XVI-XVI of FIG. 14 .

The present invention provides a substrate comprising a first pixel area and a substrate defining second and third pixel areas adjacent to the first pixel area along first and second directions, respectively; an insulating layer positioned on the substrate and including a groove between the first and second pixel regions; first electrodes disposed on the insulating layer and corresponding to each of the first to third pixel regions; a bank covering an edge of the first electrode and positioned between the first and second pixel areas and between the first and third pixel areas; a light emitting layer on the first electrode; The bank including a second electrode on the light emitting layer, positioned between the first pixel area and the second pixel area, has a first height from the first electrode, and is positioned between the first pixel area and the third pixel area. The positioned bank provides an electroluminescent display device having a second height greater than the first height from the first electrode.

In another aspect, the present invention provides a substrate comprising a first pixel area and a substrate defining second and third pixel areas adjacent to the first pixel area along first and second directions, respectively; a first electrode corresponding to each of the first to third pixel regions; a bank covering an edge of the first electrode and positioned between the first and second pixel areas and between the first and third pixel areas; a light emitting layer on the first electrode; an electric field including a second electrode on the light emitting layer, wherein a bottom of the bank between the first pixel area and the second pixel area is located lower than a bottom of the bank between the first pixel area and the second pixel area; A light emitting display device is provided.

An insulating layer disposed under the first electrode and the bank and including a groove between the first and second pixel regions may further be included.

The bank positioned between the first pixel area and the second pixel area has a first height from the first electrode, and the bank positioned between the first pixel area and the third pixel area has a height from the first electrode. It has a second height greater than the first height.

An insulating layer disposed below the first electrode and the bank and including a protrusion between the first and third pixel regions may be further included.

The groove is completely filled by the bank.

The groove has a depth smaller than the thickness of the insulating layer.

A first distance between the first pixel area and the second pixel area is smaller than a second distance between the first pixel area and the third pixel area.

Each of the first to third pixel regions has a major axis and a minor axis, and the minor axis and the major axis are parallel to the first and second directions, respectively.

The groove has the same planar shape as each of the first to third pixel regions.

Each of the first to third pixel regions has a long circular shape having a long axis and a short axis, and the groove includes a central portion and a protrusion positioned at a corner of the central portion.

The depth of the center of the groove is greater than the depth of the edge in the second direction.

The depth of the center of the groove is smaller than the depth of the edge in the second direction.

The bank has the same thickness in an area between the first and second pixel areas and in an area between the first and third pixel areas.

An end of the groove coincides with an end of the first electrode.

A width of the groove is equal to a distance between the first electrodes positioned in the first and second pixel areas.

In another aspect, the present invention provides a step of forming an insulating layer on a substrate in which a first pixel area and second and third pixel areas respectively adjacent to the first pixel area along first and second directions are defined. and; forming a first electrode on the insulating layer corresponding to each of the first to third pixel regions; etching a portion of the insulating layer to form a groove between the first and second pixel regions; forming a bank covering an edge of the first electrode and positioned between the first and second pixel areas and between the first and third pixel areas; forming a light emitting layer on the first electrode; and forming a second electrode on the light emitting layer, wherein the bank positioned between the first pixel area and the second pixel area has a first height from the first electrode, and the first pixel area and the second electrode have The bank positioned between the three pixel regions has a second height greater than the first height from the first electrode.

In the etching of the insulating layer, the first electrode is used as an etching mask.

An end of the groove coincides with an end of the first electrode.

A width of the groove is equal to a distance between the first electrodes positioned in the first and second pixel areas.

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

2 is a circuit diagram showing one pixel area of an electroluminescent display device according to an exemplary embodiment of the present invention.

As shown in FIG. 2, the electroluminescent display device according to an embodiment of the present invention includes a gate line GL and a data line DL that cross each other to define a pixel area P, and each pixel area In (P), a switching thin film transistor (Ts), a driving thin film transistor (Td), a storage capacitor (Cst), and a light emitting diode (D) are formed.

In more detail, the gate electrode of the switching thin film transistor Ts is connected to the gate line GL and the source electrode is connected to the data line DL. The gate electrode of the driving TFT Td is connected to the drain electrode of the switching TFT Ts, and the source electrode is connected to the high potential voltage VDD. The anode of the light emitting diode D is connected to the drain electrode of the driving thin film transistor Td, and the cathode is connected to the low potential voltage VSS. The storage capacitor Cst is connected to the gate electrode and drain electrode of the driving thin film transistor Td.

Looking at the image display operation of such an electroluminescent display device, the switching thin film transistor (Ts) is turned on according to the gate signal applied through the gate line (GL), and at this time, the data line (DL) The applied data signal is applied to the gate electrode of the driving thin film transistor Td and one electrode of the storage capacitor Cst through the switching thin film transistor Ts.

The driving thin film transistor (Td) is turned on according to the data signal to control the current flowing through the light emitting diode (D) to display an image. Electroluminescence (D) emits light by the current of the high potential voltage (VDD) transmitted through the driving thin film transistor (Td).

That is, since the amount of current flowing through the light emitting diode D is proportional to the size of the data signal and the intensity of light emitted from the light emitting diode D is proportional to the amount of current flowing through the light emitting diode D, the pixel area P ) displays different gradations according to the size of the data signal, and as a result, the electroluminescent display device displays an image.

The storage capacitor Cst maintains the electric charge corresponding to the data signal for one frame to keep the amount of current flowing through the light emitting diode D constant and the gray level displayed by the light emitting diode D constant. do

3 is a cross-sectional view of an electroluminescent display device according to an embodiment of the present invention, showing one pixel area.

As shown in FIG. 3 , a patterned semiconductor layer 122 is formed on the insulating substrate 110 . The substrate 110 may be a glass substrate or a flexible substrate made of a polymer such as polyimide.

The semiconductor layer 122 may be made of an oxide semiconductor material. In this case, a light blocking pattern (not shown) and a buffer layer (not shown) may be formed under the semiconductor layer 122 , and the light blocking pattern is the semiconductor layer 122 ) to prevent the semiconductor layer 122 from being degraded by light. The buffer layer may be made of an inorganic insulating material such as silicon oxide or silicon nitride. Alternatively, the semiconductor layer 122 may be made of polycrystalline silicon, and in this case, a buffer layer (not shown) may be formed between the substrate 110 and the semiconductor layer 122 . In addition, both edges of the semiconductor layer 122 made of polycrystalline silicon may be doped with impurities.

A gate insulating film 130 made of an insulating material is formed on the entire surface of the substrate 110 on the semiconductor layer 122 . The gate insulating layer 130 may be formed of an inorganic insulating material such as silicon oxide (SiO ₂ ). When the semiconductor layer 122 is made of polycrystalline silicon, the gate insulating layer 130 may be made of silicon oxide (SiO ₂ ) or silicon nitride (SiNx).

A gate electrode 132 made of a conductive material such as metal is formed on the gate insulating layer 130 corresponding to the center of the semiconductor layer 122 . In addition, a gate wiring (not shown) and a first capacitor electrode (not shown) may be formed on the gate insulating layer 130 . The gate wiring extends in one direction, and the first capacitor electrode is connected to the gate electrode 132 .

Meanwhile, in the embodiment of the present invention, the gate insulating film 130 is formed on the entire surface of the substrate 110, but the gate insulating film 130 may be patterned in the same shape as the gate electrode 132.

An interlayer insulating film 140 made of an insulating material is formed on the entire surface of the substrate 110 above the gate electrode 132 . The interlayer insulating film 140 may be formed of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx), or an organic insulating material such as photo acryl or benzocyclobutene. .

The interlayer insulating layer 140 has first and second contact holes 140a and 140b exposing top surfaces of both sides of the semiconductor layer 122 . The first and second contact holes 140a and 140b are spaced apart from the gate electrode 132 on both sides of the gate electrode 132 . Here, the first and second contact holes 140a and 140b are also formed in the gate insulating layer 130 . In contrast, when the gate insulating layer 130 is patterned in the same shape as the gate electrode 132 , the first and second contact holes 140a and 140b are formed only in the interlayer insulating layer 140 .

Source and drain electrodes 152 and 154 are formed on the interlayer insulating film 140 with a conductive material such as metal. In addition, a data line (not shown), a power line (not shown), and a second capacitor electrode (not shown) may be formed on the interlayer insulating film 140 .

The source and drain electrodes 152 and 154 are spaced apart from each other about the gate electrode 132 and contact both sides of the semiconductor layer 122 through first and second contact holes 140a and 140b, respectively. Although not shown, the data line extends in a direction perpendicular to the gate line and intersects the gate line to define a pixel area, and the power line supplying a high potential voltage is spaced apart from the data line. The second capacitor electrode is connected to the drain electrode 154 and overlaps with the first capacitor electrode to form a storage capacitor with the interlayer insulating film 140 between the two as a dielectric.

Meanwhile, the semiconductor layer 122, the gate electrode 132, and the source and drain electrodes 152 and 154 form a thin film transistor. Here, the thin film transistor has a coplanar structure in which the gate electrode 132 and the source and drain electrodes 152 and 154 are located on one side of the semiconductor layer 122, that is, on top of the semiconductor layer 122.

Alternatively, the thin film transistor may have an inverted staggered structure in which a gate electrode is positioned below the semiconductor layer and source and drain electrodes are positioned above the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon.

Here, the thin film transistor corresponds to the driving thin film transistor of the electroluminescent display device, and a switching thin film transistor (not shown) having the same structure as the driving thin film transistor is further formed on the substrate 110 . The gate electrode 132 of the driving TFT is connected to the drain electrode (not shown) of the switching TFT and the source electrode 152 of the driving TFT is connected to a power line (not shown). In addition, a gate electrode (not shown) and a source electrode (not shown) of the switching thin film transistor are respectively connected to a gate line and a data line.

On the source and drain electrodes 152 and 154, a protective film 160 made of an insulating material is formed substantially on the entire surface of the substrate 110. The protective layer 160 may be formed of an organic insulating material such as benzocyclobutene or photo acryl. Meanwhile, an inorganic insulating layer made of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx) may be further formed under the protective layer 160 .

The passivation layer 160 has a drain contact hole 160a exposing the drain electrode 154 . Here, the drain contact hole 160a is illustrated as being formed directly above the second contact hole 140b, but may be formed spaced apart from the second contact hole 140b.

A first electrode 162 is formed of a conductive material having a relatively high work function on the protective layer 160 . The first electrode 162 contacts the drain electrode 154 through the drain contact hole 160a. For example, the first electrode 162 may be formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

A bank 170 is formed of an insulating material on the first electrode 162 . The bank 170 is located between adjacent pixel areas, has a transmission hole 170a exposing the first electrode 162 , and covers an edge of the first electrode 162 .

The bank 170 includes a first bank 172 and a second bank 174 over the first bank 172, and the width of the first bank 172 is wider than that of the second bank 174. The first bank 172 is made of a material with a relatively high surface energy to lower the contact angle with the light-emitting layer material to be formed later, and the second bank 174 is made of a material with a relatively low surface energy to reduce contact with the light-emitting layer material to be formed later. By increasing the contact angle, overflow of the light emitting layer material into adjacent pixel areas is prevented. For example, the first bank 172 may be made of an inorganic insulating material or organic insulating material having hydrophilic properties, and the second bank 174 may be made of an organic insulating material having hydrophobic properties.

Alternatively, the first bank 172 and the second bank 174 may have an integral structure made of the same material, and in this case, the first bank 172 and the second bank 174 are made of an organic insulating material having hydrophobic properties. It can be done.

Alternatively, the bank may have a single layer structure made of an organic insulating material having hydrophobic properties.

An emission layer 180 is formed on the first electrode 162 exposed through the transmission hole 170a of the bank 170 . The light emitting layer 180 may be formed through a solution process. As the solution process, a printing method or a coating method using a spraying device including a plurality of nozzles may be used, but is not limited thereto. For example, an inkjet printing method may be used as a solution process.

Although not shown, the light emitting layer 180 includes a hole auxiliary layer, a light emitting material layer, and an electron auxiliary layer sequentially stacked from the top of the first electrode 162. can include The hole auxiliary layer may include at least one of a hole injecting layer and a hole transporting layer, and the electron auxiliary layer is selected from among the electron transporting layer and the electron injecting layer. may contain at least one.

Here, the hole auxiliary layer and the light emitting material layer may be formed only in the transmission hole 170a, and the electron auxiliary layer may be substantially formed on the entire surface of the substrate 110 . In this case, the hole auxiliary layer and the light emitting material layer may be formed through a solution process, and the electron auxiliary layer may be formed through a vacuum deposition process.

On the light emitting layer 180 , a second electrode 192 made of a conductive material having a relatively low work function is formed substantially on the entire surface of the substrate 110 . Here, the second electrode 192 may be formed of aluminum, magnesium, silver, or an alloy thereof.

The first electrode 162, the light emitting layer 180, and the second electrode 192 form a light emitting diode (D), the first electrode 162 serves as an anode, and the second electrode 192 It acts as a cathode.

Although not shown, an encapsulation film (not shown) may be formed on the second electrode 192 to prevent external moisture from penetrating into the organic light emitting diode D. For example, the encapsulation film may have a stacked structure of a first inorganic insulating layer, an organic insulating layer, and a second inorganic insulating layer, but is not limited thereto.

Here, the electroluminescent display device according to the embodiment of the present invention may be a bottom emission type in which light emitted from the light emitting layer 180 is output to the outside through the first electrode 162 .

Unlike this, the electroluminescent display device according to an embodiment of the present invention may be a top emission type in which light emitted from the light emitting layer 180 is output to the outside through the second electrode 192 . In this case, the first electrode 162 further includes a reflective layer (not shown) made of an opaque conductive material. For example, the reflective layer may be formed of an aluminum-palladium-copper (APC) alloy, and the first electrode 162 may have a triple layer structure of ITO/APC/ITO. In addition, the second electrode 192 has a relatively thin thickness to transmit light, and light transmittance of the second electrode 192 may be about 45-50%.

In the electroluminescent display device according to this embodiment of the present invention, the bank 170 has different heights from the first electrode 162 in the direction of the long axis and the direction of the short axis of the pixel area. This will be described in more detail with reference to the drawings.

-First Embodiment-

4 is a schematic plan view of an electroluminescent display device according to the first embodiment of the present invention, and FIGS. 5, 6, and 7 are schematic cross-sectional views of the electroluminescent display device according to the first embodiment of the present invention. 5 corresponds to line V-V in FIG. 4 , FIG. 6 corresponds to line VI-VI in FIG. 4 , and FIG. 7 corresponds to line VII-VII in FIG. 4 . For convenience, only the bank and the first electrode are shown in FIG. 4, and descriptions of the same parts as in the previous embodiment are omitted or simplified.

As shown in FIGS. 4 to 7 , a plurality of pixel regions P are defined on the substrate 110 .

Here, the pixel region P corresponds to an effective light emitting region where light is emitted, and a distance between adjacent pixel regions P is different in a first direction and a second direction due to the arrangement of a plurality of wires and elements. That is, adjacent pixel regions P along the first direction are spaced apart with a first distance d1, and adjacent pixel regions P along a second direction perpendicular to the first direction have a second distance d2. and are spaced apart, the second distance d2 is greater than the first distance d1. In this case, each pixel region P may have a rectangular shape having a major axis and a minor axis in plan view, the minor axis being parallel to the first direction, and the major axis being parallel to the second direction.

A first pixel area P1, a second pixel area P2 adjacent to the first pixel area P1 along a first direction (horizontal direction), and a first pixel area P1 along a second direction (vertical direction) When the third pixel area P3 adjacent to is arranged, the first and second pixel areas P1 and P2 are spaced apart by a first distance d1 and the first and third pixel areas P1 and P3 are separated from each other by a first distance d1. They are spaced apart by 2 distances (d2).

A gate insulating layer 130 , an interlayer insulating layer 140 , and a protective layer 160 are formed on the substrate 110 .

The gate insulating film 130 may be formed of silicon oxide (SiO ₂ ) or silicon nitride (SiNx), and the interlayer insulating film 140 may be formed of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx). , It may be formed of an organic insulating material such as photo acryl or benzocyclobutene, and the passivation layer 160 may be formed of an organic insulating material such as benzocyclobutene or photo acryl. An inorganic insulating film made of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx) may be further formed between the interlayer insulating film 140 and the protective film 160 .

The passivation layer 160 has grooves 160b between adjacent pixel regions P in the first direction, and the grooves 160b may have a rectangular shape. The groove 160b is formed on the passivation layer 160 between the first and second pixel regions P1 and P2 and is not formed on the passivation layer 160 between the first and third pixel regions P1 and P3. This groove 160b will be described in detail later.

Meanwhile, under the protective film 160, a switching thin film transistor (not shown), a driving thin film transistor (not shown), a storage capacitor (not shown), a gate wiring (not shown), a data wiring (not shown), And power wiring (not shown) is formed. Here, the switching thin film transistor (not shown) and the driving thin film transistor (not shown) may have the same structure as that shown in FIG. 3 .

A first electrode 162 is formed of a conductive material having a relatively high work function on the protective layer 160 . The first electrode 162 is formed in each pixel region P and contacts a drain electrode (not shown) of a driving thin film transistor (not shown) through a drain contact hole (not shown) of the passivation layer 160. do.

A bank 170 is formed of an insulating material above the first electrode 162, and the bank 170 is positioned between adjacent pixel regions P. The bank 170 has a transmissive hole 170a exposing the first electrode 162 corresponding to each pixel region P, and covers an edge of the first electrode 162 . Here, the transmission hole 170a has a rectangular shape.

The bank 170 includes a first bank 172 and a second bank 174 over the first bank 172 . The first bank 172 is made of a material with a relatively high surface energy to lower the contact angle with the light-emitting layer material to be formed later, and the second bank 174 is made of a material with a relatively low surface energy to reduce contact with the light-emitting layer material to be formed later. By increasing the contact angle, overflow of the light emitting layer material to the adjacent pixel region P is prevented. Here, the surface energy of the first bank 172 is higher than that of the second bank 174 . For example, the first bank 172 may be made of an inorganic insulating material or an organic insulating material having hydrophilic properties, and the second bank 174 may be made of an organic insulating material having hydrophobic properties.

The first bank 172 has a first transmission hole 172a, the second bank 174 has a second transmission hole 174a, and the first transmission hole 172a and the second transmission hole 174a are It forms a transmission hole (170a). At this time, the area of the second transmission hole 174a is larger than the area of the first transmission hole 172a. Accordingly, the width of the first bank 172 is wider than that of the second bank 174, and a portion of the first bank 172 is exposed without being covered by the second bank 174. The first and second banks 172 and 174 may be formed through each photolithography process using a mask.

Alternatively, the first bank 172 and the second bank 174 may be formed through a single photolithography process as an integral structure made of the same material. In this case, the first bank 172 and the second bank 174 may be made of an organic insulating material having hydrophobic properties.

Alternatively, the bank may have a single layer structure made of an organic insulating material having hydrophobic properties.

Subsequently, a light emitting layer (not shown) is formed on the first electrode 162 exposed through the transmission hole 170a of the bank 170, and a second electrode (not shown) is formed on the light emitting layer with a conductive material having a relatively low work function. not) is formed on the entire surface of the substrate 110. The light emitting layer may include a hole auxiliary layer, a light emitting material layer, and an electron auxiliary layer, and a part or all of the light emitting layer is formed through a solution process. For example, the hole auxiliary layer and the light emitting material layer may be formed through a solution process. The hole auxiliary layer includes at least one of a hole injection layer and a hole transport layer, and the electron auxiliary layer includes at least one of an electron injection layer and an electron transport layer.

As mentioned above, the passivation layer 160 has grooves 160b between adjacent pixel regions P in the first direction, and the height of the bank 170 is increased by the grooves 160b of the passivation layer 160 in the first direction. and are different for the second direction.

More specifically, the banks 170 are formed along the steps of the grooves 160b of the passivation layer 160, and the banks 170 between adjacent pixel regions P in the first direction are formed on the top surface of the first electrode 162. The bank 170 between the adjacent pixel regions P in the second direction has a second height h2 from the upper surface of the first electrode 162 and has a first height h1 ) is lower than the second height h2.

As in the present invention, when the second distance d2 between adjacent pixel regions P along the second direction is greater than the first distance d1 between adjacent pixel regions P along the first direction, the bank ( 170) has the same height in the first and second directions, the thickness of the light emitting layer is different because the adjacent pixel regions P have different influences on the first and second directions in forming the light emitting layer by the solution process. will not be uniform.

That is, when the bank 170 has the same height in the first direction and the second direction, when the solution is dropped on the pixel area P and then dried, the height of the adjacent pixel area P is relatively close to the first direction. While the effect of the solution is large, the effect of the solution in the adjacent pixel area P is small in the relatively distant second direction. Therefore, since a difference in the evaporation rate of the solvent occurs in the first and second directions, and the evaporation rate of the solvent in the second direction is faster than the evaporation rate of the solvent in the first direction, it is difficult to obtain a light emitting layer having a uniform thickness.

Accordingly, in the present invention, the groove 160b is formed in the passivation layer 160 so that the upper surface of the bank 170 between adjacent pixel regions P in the first direction is formed between adjacent pixel regions P in the second direction. By lowering the top surface of the bank 170, the first height h1 of the bank 170 between pixel regions P adjacent to each other in the first direction is increased by increasing the first height h1 of the bank 170 between pixel regions P adjacent to each other in the second direction. ) to be lower than the second height h2.

That is, the bank 170 between pixel regions P adjacent in the first direction and the bank 170 between pixel regions P adjacent in the second direction have the same thickness, but are formed by the groove 160b in the first direction. Since the height of the bottom of the bank 170 between the adjacent pixel regions P is smaller than the height of the bottom of the bank 170 between the adjacent pixel regions P in the second direction, the pixel region P adjacent to the first direction The first height h1 of the banks 170 between them is smaller than the second height h2 of the banks 170 between adjacent pixel regions P in the second direction.

Meanwhile, without the groove 160b, the bank 170 may have different heights and different thicknesses in the first and second directions. However, in this case, a problem of non-uniform thickness or non-uniform profile of the organic layer (emission layer) may occur. In the solution process of the organic layer, the hydrophobicity of the bank is one of the important factors related to the thickness non-uniformity or profile non-uniformity problem. However, in the process of imparting hydrophobicity to the bank, in the case of a bank having a thickness variation, a variation in hydrophobicity may occur in a space between adjacent pixel regions along the first and second directions. For example, a portion of a bank having a large thickness may have less hydrophobicity than a portion of a bank having a small thickness. Accordingly, a problem of thickness non-uniformity or profile non-uniformity may occur in the organic layer of the pixel region.

However, in the present invention, since the bank 170 has a height difference but the same thickness in the first and second directions due to the groove 160b, the above problem is prevented.

In this case, the first height h1 may be similar to the conventional bank height, and the second height h2 may be higher than the conventional bank height. In this case, by confining more solution in the pixel area P in the second direction compared to the prior art, the evaporation rate of the solvent in the second direction is lowered, so that the evaporation rate of the solvent in the first and second directions is uniform. Thus, a thin film having a uniform thickness can be formed.

Alternatively, the first height h1 may be lower than the conventional bank height, and the second height h2 may be similar to the conventional bank height. In this case, by confining less solution in the pixel area P in the first direction compared to the prior art, the evaporation rate of the solvent in the first direction is increased, so that the evaporation rate of the solvent in the first direction and the second direction is uniform. By doing so, it is possible to form a thin film having a uniform thickness.

For example, when the hole injection layer is formed by the solution process according to the first embodiment of the present invention, the maximum deviation of the thin film thickness in the first direction compared to the thin film thickness at the center of the pixel region P is about 5.3 nm, and the average The deviation is about 2.45 nm, the maximum deviation of the thin film thickness in the second direction is about 12.2 nm and the average deviation is about 5.77 nm. On the other hand, as a comparative example, when banks having the same height in the first and second directions are formed and the hole injection layer is formed by the solution process, the maximum thickness of the thin film in the first direction compared to the thickness of the thin film in the center of the pixel region The deviation is about 8.4 nm and the average deviation is about 3.40 nm, the maximum deviation of the thin film thickness in the second direction is about 15.7 nm and the average deviation is about 12.7 nm. Therefore, according to the first embodiment of the present invention, it can be seen that the uniformity of the thickness of the thin film by the solution process can be improved.

Meanwhile, although the depth of the groove 160a is smaller than the thickness of the protective film 160 in the drawings, it is not limited thereto. That is, the depth of the groove 160a may be the same as the thickness of the passivation layer 160, and in this case, the lower interlayer insulating layer 140 may be exposed through the groove 160a.

As described above, in the electroluminescent display device according to the first embodiment of the present invention, since part or all of the light emitting layer is formed through a solution process applicable to a relatively small area, the manufacturing cost can be reduced by reducing the deposition process. It can also be applied to area and high-resolution display devices.

In addition, a thin film having a uniform thickness may be formed by making the evaporation rate of the solvent in the first and second directions uniform by varying the heights of the banks in the first and second directions. Therefore, the image quality can be improved.

In addition, the efficiency and lifespan of electroluminescence, driving voltage, color characteristics, and the like can be improved.

The shape of the groove 160b of the passivation layer 160 may vary depending on the shape of the pixel region P corresponding to the effective light emitting region from which light is emitted.

8 is a schematic plan view of another example of an electroluminescent display device according to the first embodiment of the present invention.

As shown in FIG. 8, a plurality of pixel regions P are defined on the substrate (110 in FIG. 5), and each pixel region P may have a substantially long circular shape having a major axis and a minor axis in plan view. . Here, the minor axis is parallel to the first direction, and the major axis is parallel to the second direction.

Corresponding to each pixel region P, a bank 170 having a transmission hole 170a is formed. Accordingly, the penetration hole 170a has a substantially long circular shape having a major axis and a minor axis in plan view.

The bank 170 includes a first bank 172 and a second bank 174 over the first bank 172 . The first bank 172 has a first transmission hole 172a, the second bank 174 has a second transmission hole 174a, and the first transmission hole 172a and the second transmission hole 174a are It forms a transmission hole (170a). At this time, the area of the second transmission hole 174a is larger than the area of the first transmission hole 172a. Accordingly, the width of the first bank 172 is wider than that of the second bank 174, and a portion of the first bank 172 is exposed without being covered by the second bank 174.

A groove 160b is formed in the passivation layer ( 110 in FIG. 5 ) between adjacent pixel regions P in the first direction. At this time, the side of the groove 160b facing the penetration hole 170a has the same shape as the side of the penetration hole 170a. Accordingly, the distance between the penetration hole 170a and the groove 160b is constant.

For example, the groove 160b may have a substantially rectangular shape having protrusions extending toward the penetration hole 170a at four corners.

As such, the shape of the groove 160b may vary depending on the shape of the pixel region P, that is, the shape of the transmission hole 170a, and the distance between the transmission hole 170a and the groove 160a is preferably constant. .

-Second Embodiment-

9 is a schematic cross-sectional view of an electroluminescent display device according to a second embodiment of the present invention, corresponding to line VII-VII of FIG. 4 . The electroluminescent display device according to the second embodiment of the present invention has the same structure as the first embodiment except for the groove, and descriptions of the same parts are omitted or simplified.

As shown in FIG. 9 , a gate insulating film 230 , an interlayer insulating film 240 , and a protective film 260 are sequentially formed on the substrate 210 . A bank 270 including first and second banks 272 and 274 is formed on the protective layer 260 .

The passivation layer 260 has grooves 260b between adjacent pixel regions (P in FIG. 4 ) in the first direction, and the upper surface of the bank 270 corresponding to the groove 260b is lower than other portions.

Here, the center of the groove 260b may be deeper than both ends along the second direction. More specifically, the groove 260b has a structure in which the depth is the deepest in the center and gradually becomes shallower toward both ends along the second direction, so that the protective film 260 corresponding to the groove 260b is formed on the substrate 210 may have a convex surface towards

Such a groove 260b may be formed through a photolithography process using a mask in which an exposure amount gradually increases or decreases towards both ends compared to the center.

-Third Embodiment-

10 is a schematic cross-sectional view of an electroluminescent display device according to a third embodiment of the present invention, corresponding to line VII-VII of FIG. 4 . The electroluminescent display device according to the third embodiment of the present invention has the same structure as the first embodiment except for the groove, and descriptions of the same parts are omitted or simplified.

As shown in FIG. 10 , a gate insulating layer 330 , an interlayer insulating layer 340 , and a protective layer 360 are sequentially formed on a substrate 310 . A bank 370 including first and second banks 372 and 374 is formed on the protective layer 360 .

The passivation layer 360 has grooves 360b between adjacent pixel regions (P in FIG. 4 ) in the first direction, and the upper surface of the bank 370 corresponding to the groove 360b is lower than other portions.

Here, the depth of both ends of the groove 360b may be lower than the depth of the center along the second direction. More specifically, the groove 360b may have a structure having a double step difference by having a first depth corresponding to the center and having a second depth lower than the first depth on both sides of the center along the second direction.

Such a groove 360b may be formed through a photolithography process using at least two masks having different transmittances or using a mask including at least two transflective regions having different transmittances.

The groove 360b according to the third embodiment of the present invention is advantageous in forming a conventional W-shaped thin film with a uniform thickness.

-Fourth Embodiment-

11 is a schematic cross-sectional view of an electroluminescent display device according to a fourth embodiment of the present invention, corresponding to line VII-VII of FIG. 4 . The electroluminescent display device according to the fourth embodiment of the present invention has the same structure as the first embodiment except for the groove, and descriptions of the same parts are omitted or simplified.

As shown in FIG. 11 , a gate insulating layer 430 , an interlayer insulating layer 440 , and a protective layer 460 are sequentially formed on a substrate 410 . A bank 470 including first and second banks 472 and 474 is formed on the passivation layer 460 .

The passivation layer 460 has grooves 460b between adjacent pixel regions (P in FIG. 4 ) in the first direction, and the upper surface of the bank 470 corresponding to the groove 460b is lower than other portions.

Here, the depth of both ends of the groove 460b along the second direction may be greater than that of the center. More specifically, the groove 460b has a structure in which the central depth is the shallowest and the depth gradually deepens toward both ends along the second direction, so that the protective film 460 corresponding to the groove 460b forms a bank 470. It may have a convex surface towards the

At this time, the height of the edge of the bank 470 facing the penetration hole is effectively reduced by the groove 460b, so that the solvent evaporation rate of the light emitting material solution is effectively increased. Accordingly, the thickness uniformity of the light emitting layer is improved.

Such a groove 460b may be formed through a photolithography process using a mask in which an exposure amount gradually increases or decreases towards both ends compared to the center.

The groove 460b according to the fourth embodiment of the present invention is advantageous in forming a conventional W-shaped thin film with a uniform thickness.

FIG. 12 is a schematic cross-sectional view of an electroluminescent display device according to a fifth embodiment of the present invention, showing a cross-section corresponding to line VII-VII of FIG. 4 .

12, a gate insulating layer 530, an interlayer insulating layer 540, and a protective layer 560 are sequentially formed on or above the substrate 510, and the first and second banks 570a and 570b are formed. A bank 570 including a bank 570 is formed on the protective layer 560 .

The passivation layer 560 has grooves 560b between adjacent pixel regions (P in FIG. 4 ) in the first direction. The width of the groove 560b is substantially the same as the distance between adjacent first electrodes 562, and a portion of the height of the bank 570 within the groove 560b is reduced.

The groove 560b has a rectangular cross section. Alternatively, as shown in FIG. 9 or 11, the groove 560b may have a round cross section.

In the present invention, the height of the bank 570 between adjacent pixel regions along the first direction is smaller than the height of the bank 570 between adjacent pixel regions along the second direction. Therefore, even though the distance between the adjacent pixel areas is different in the first and second directions, the solvent evaporation rate of the light emitting material solution becomes uniform, and accordingly, a light emitting layer having uniform thickness is formed.

13A to 13C are schematic cross-sectional views showing manufacturing processes for a part of an electroluminescent display device according to a fifth embodiment of the present invention.

As shown in FIG. 13A , a gate insulating film 530, an interlayer insulating film 540, and a protective film 560 are formed on a substrate 510, and a conductive material layer (not shown) is formed on the protective film 560. . The conductive material layer may include a transparent conductive material such as ITO or IZO. Next, a conductive material layer is patterned to form a first electrode 562 in each pixel area.

Referring to FIG. 3 , before forming the gate insulating film 530, the semiconductor layer 122 is formed on the substrate 510, and before forming the interlayer insulating film 540, the gate electrode 132 is formed on the gate insulating film 530. formed on the In addition, before forming the protective film 560 , the source electrode 152 and the drain electrode 154 are formed on the interlayer insulating film 540 .

Next, as shown in FIG. 13B , a groove 560b is formed by patterning a portion of the passivation layer 560 by an etching process using the first electrode 562 as an etching mask. The etching process may be an anisotropic dry etching process. Accordingly, the end of the groove 560b exactly matches or corresponds to the end of the first electrode 562 . That is, the width of the groove 560b is substantially the same as the distance between adjacent first electrodes 562 .

Alternatively, the passivation layer 560 may be patterned before forming the first electrode 562 to form the groove 560b. The groove 560b and the drain contact hole ( 160a in FIG. 3 ) may be formed by one mask process. In this case, mis-alignment between the first electrode 562 and the groove 560b may occur, and accordingly, the end of the first electrode 562 is located in the groove 560b and is in the groove 560b. The height of the corresponding bank 570 may increase.

However, when the groove 560b is formed by an etching process using the first electrode 562 as an etching mask, the above problem can be prevented because the first electrode 562 is not formed in the groove 560b.

Next, as shown in FIG. 13C, an insulating material layer (not shown) is formed on the first electrode 562 and the passivation layer 560, and the insulating material layer is patterned to form a bank 570. Although not shown, a light emitting layer ( 180 in FIG. 3 ) and a second electrode ( 192 in FIG. 3 ) are formed on the first electrode 562 . The light emitting layer 180 and the second electrode 192 may also be formed on the bank 570 .

14 is a schematic plan view of an electroluminescent display device according to a sixth embodiment of the present invention, and FIG. 15 is a schematic plan view of an electroluminescence display device according to a sixth embodiment of the present invention corresponding to line XV-XV of FIG. FIG. 16 is a schematic cross-sectional view of an electroluminescent display device according to a sixth embodiment of the present invention corresponding to line XVI-XVI of FIG. 14 .

As shown in FIGS. 14 to 16 , a plurality of pixel regions P are defined on the substrate 610 .

Here, the pixel region P corresponds to an effective light emitting region where light is emitted, and a distance between adjacent pixel regions P is different in a first direction and a second direction due to the arrangement of a plurality of wires and elements. That is, adjacent pixel regions P along the first direction are spaced apart with a first distance d1, and adjacent pixel regions P along a second direction perpendicular to the first direction have a second distance d2. and are spaced apart, the second distance d2 is greater than the first distance d1. In this case, each pixel region P may have a rectangular shape having a major axis and a minor axis in plan view, the minor axis being parallel to the first direction, and the major axis being parallel to the second direction.

A first pixel area P1, a second pixel area P2 adjacent to the first pixel area P1 along a first direction (horizontal direction), and a first pixel area P1 along a second direction (vertical direction) When the third pixel area P3 adjacent to is arranged, the first and second pixel areas P1 and P2 are spaced apart by a first distance d1 and the first and third pixel areas P1 and P3 are separated from each other by a first distance d1. They are spaced apart by 2 distances (d2).

A gate insulating layer 630 , an interlayer insulating layer 640 , and a passivation layer 660 are formed on the substrate 610 .

The gate insulating film 630 may be formed of silicon oxide (SiO ₂ ) or silicon nitride (SiNx), and the interlayer insulating film 640 may be formed of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx). , It may be formed of an organic insulating material such as photo acryl or benzocyclobutene, and the passivation layer 660 may be formed of an organic insulating material such as benzocyclobutene or photo acryl. An inorganic insulating film made of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx) may be further formed between the interlayer insulating film 640 and the passivation film 660 .

The passivation layer 660 has a protrusion 661 between adjacent pixel regions P in the second direction. That is, the protective layer 660 has a protrusion 661 between the first and third pixel regions P1 and P3. Therefore, from the substrate 610, the upper surface of the passivation layer 660 has a third height h3 between the first and second pixel regions P1 and P2 adjacent in the first direction and is adjacent in the second direction. A fourth height h4 greater than the third height h3 is provided between the first and third pixel regions P1 and P3. The protrusion 661 is formed on the passivation layer 660 between the first and third pixel regions P1 and P3, and is not formed on the passivation layer 660 between the first and second pixel regions P1 and P2. . Thus, the passivation layer 660 between the first and second pixel regions P1 and P2 has a flat upper surface.

Meanwhile, under the protective film 660, a switching thin film transistor (not shown), a driving thin film transistor (not shown), a storage capacitor (not shown), a gate wiring (not shown), a data wiring (not shown), And power wiring (not shown) is formed.

A first electrode 662 is formed of a conductive material having a relatively high work function on the protective layer 660 . The first electrode 662 is formed in each pixel region P and contacts a drain electrode (not shown) of a driving thin film transistor (not shown) through a drain contact hole (not shown) of the passivation layer 660. do.

A bank 670 is formed of an insulating material on the first electrode 662, and the bank 670 is positioned between adjacent pixel regions P. The bank 670 has a transmissive hole 670a exposing the first electrode 662 corresponding to each pixel region P, and covers an edge of the first electrode 662 . Here, the penetration hole 670a has a rectangular shape or a long circular shape having a major axis and a minor axis.

The bank 670 includes a first bank 672 and a second bank 674 over the first bank 672 . The first bank 672 is made of a material with a relatively high surface energy to lower the contact angle with the light-emitting layer material to be formed later, and the second bank 674 is made of a material with a relatively low surface energy to reduce contact with the light-emitting layer material to be formed later. By increasing the contact angle, overflow of the light emitting layer material to the adjacent pixel region P is prevented. Here, the surface energy of the first bank 672 is higher than that of the second bank 674 . For example, the first bank 672 may be made of an inorganic insulating material or an organic insulating material having hydrophilic properties, and the second bank 674 may be made of an organic insulating material having hydrophobic properties.

The first bank 672 has a first transmission hole 672a, the second bank 674 has a second transmission hole 674a, and the first transmission hole 672a and the second transmission hole 674a are It forms a transmission hole (670a). In this case, the area of the second transmission hole 674a is larger than the area of the first transmission hole 672a. Accordingly, the width of the first bank 672 is wider than that of the second bank 674, and a portion of the first bank 672 is exposed without being covered by the second bank 674. The first and second banks 672 and 674 may be formed through each photolithography process using a mask.

Alternatively, the first bank 672 and the second bank 674 may be formed through a single photolithography process as an integral structure made of the same material. In this case, the first bank 672 and the second bank 674 may be made of an organic insulating material having hydrophobic properties.

Alternatively, the bank may have a single layer structure made of an organic insulating material having hydrophobic properties.

Subsequently, a light emitting layer (not shown) is formed on the first electrode 662 exposed through the transmission hole 670a of the bank 670, and a second electrode (not shown) is formed on the light emitting layer with a conductive material having a relatively low work function. not) is formed on the entire surface of the substrate 610 . The light emitting layer may include a hole auxiliary layer, a light emitting material layer, and an electron auxiliary layer, and a part or all of the light emitting layer is formed through a solution process. For example, the hole auxiliary layer and the light emitting material layer may be formed through a solution process. The hole auxiliary layer includes at least one of a hole injection layer and a hole transport layer, and the electron auxiliary layer includes at least one of an electron injection layer and an electron transport layer.

As mentioned above, the passivation layer 660 has protrusions 661 between adjacent pixel regions P in the second direction, and the height of the bank 670 is increased by the protrusions 661 of the passivation layer 660 in the first direction. and are different for the second direction.

More specifically, the bank 670 is formed along the step of the protruding portion 661 of the protective film 660, so that the bank 670 between adjacent pixel regions P in the first direction is removed from the upper surface of the substrate 610. The bank 670 between pixel regions P adjacent to each other in the second direction has a sixth height h6 from the upper surface of the substrate 610, and the fifth height h5 is the sixth height h5. It is smaller than the height (h6).

As in the present invention, when the second distance d2 between adjacent pixel regions P along the second direction is greater than the first distance d1 between adjacent pixel regions P along the first direction, the bank ( 670) have the same height in the first direction and the second direction, the thickness of the light emitting layer is different because the adjacent pixel regions P have different influences on the first and second directions in forming the light emitting layer by the solution process. will not be uniform.

That is, when the bank 670 has the same height in the first direction and the second direction, when the solution is dropped on the pixel area P and then dried, the height of the adjacent pixel area P in the relatively close first direction While the effect of the solution is large, the effect of the solution in the adjacent pixel area P is small in the relatively distant second direction. Therefore, since a difference in the evaporation rate of the solvent occurs in the first and second directions, and the evaporation rate of the solvent in the second direction is faster than the evaporation rate of the solvent in the first direction, it is difficult to obtain a light emitting layer having a uniform thickness.

In the present invention, the protrusion 661 is formed on the passivation layer 660 between the pixel regions P adjacent in the second direction so that the upper surface of the bank 670 between the pixel regions P adjacent in the first direction is formed in the second direction. By making the fifth height h5 of the bank 670 between the pixel regions P adjacent in the first direction lower than the upper surface of the bank 670 between the pixel regions P adjacent in the first direction, the fifth height h5 of the bank 670 adjacent in the second direction It is smaller than the sixth height h6 of the bank 670 between the pixel regions P.

That is, the bank 670 between pixel regions P adjacent in the first direction and the bank 670 between pixel regions P adjacent in the second direction have the same thickness, but are formed by the protrusion 661 in the first direction. Since the third height h3 of the bottom of the bank 670 between the adjacent pixel regions P is smaller than the fourth height h4 of the bottom of the bank 670 between the adjacent pixel regions P in the second direction, The fifth height h5 of the bank 670 between pixel regions P adjacent in the first direction is smaller than the sixth height h6 of the bank 670 between pixel regions P adjacent in the second direction. .

In the electroluminescent display device according to the sixth embodiment of the present invention, since part or all of the light emitting layer is formed through a solution process, manufacturing cost can be reduced by reducing the deposition process, and can be applied to a large area and high resolution display device. .

In addition, a thin film having a uniform thickness may be formed by making the evaporation rate of the solvent in the first and second directions uniform by varying the heights of the banks in the first and second directions. Therefore, the image quality can be improved.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art may variously modify the present invention within the scope not departing from the technical spirit and scope of the present invention described in the claims below. And it will be understood that it can be changed.

110: substrate 122: semiconductor layer
130: gate insulating film 132: gate electrode
140: interlayer insulating film 140a, 140b: first and second contact holes
142: source electrode 144: drain electrode
152, 154: first and second protective films 156: drain contact hole
162: first electrode 170: bank
170a: transmission hole 180: light emitting layer
192: second electrode D: light emitting diode

Claims (21)

a substrate defining a first pixel area and second and third pixel areas respectively adjacent to the first pixel area along first and second directions;
an insulating layer positioned on the substrate and including a groove between the first and second pixel regions;
first electrodes disposed on the insulating layer and corresponding to each of the first to third pixel regions;
a bank covering an edge of the first electrode and positioned between the first and second pixel areas and between the first and third pixel areas;
a light emitting layer on the first electrode;
A second electrode on the light emitting layer;
The bank positioned between the first pixel area and the second pixel area has a first height from the first electrode, and the bank positioned between the first pixel area and the third pixel area has a height from the first electrode. Has a second height greater than the first height,
Each of the first to third pixel regions has a long circular shape having a major axis and a minor axis, and the groove includes a central portion and a protrusion positioned at a corner of the central portion.
a substrate defining a first pixel area and second and third pixel areas respectively adjacent to the first pixel area along first and second directions;
a first electrode corresponding to each of the first to third pixel regions;
a bank covering an edge of the first electrode and positioned between the first and second pixel areas and between the first and third pixel areas;
a light emitting layer on the first electrode;
A second electrode on the light emitting layer;
A bottom of the bank is located lower than a bottom of the first electrode between the first pixel area and the second pixel area;
an insulating layer positioned under the first electrode and the bank and including a groove between the first and second pixel regions;
The electroluminescent display device of claim 1 , wherein the depth of the center of the groove is smaller than the depth of the edge of the groove in the second direction.

delete According to claim 2,
The bank positioned between the first pixel area and the second pixel area has a first height from the first electrode, and the bank positioned between the first pixel area and the third pixel area has a height from the first electrode. An electroluminescent display device having a second height greater than the first height.
a substrate defining a first pixel area and second and third pixel areas respectively adjacent to the first pixel area along first and second directions;
a first electrode corresponding to each of the first to third pixel regions;
a bank covering an edge of the first electrode and positioned between the first and second pixel areas and between the first and third pixel areas;
a light emitting layer on the first electrode;
A second electrode on the light emitting layer;
The bottom of the bank between the first pixel area and the second pixel area is positioned lower than the bottom of the bank between the first pixel area and the third pixel area;
and an insulating layer positioned under the first electrode and the bank and including a protrusion between the first and third pixel regions.
According to claim 1 or 2,
wherein the groove is completely filled by the bank.
According to claim 1 or 2,
The electroluminescent display device of claim 1 , wherein the groove has a depth smaller than a thickness of the insulating layer.
According to claim 1 or 2,
A first distance between the first pixel region and the second pixel region is smaller than a second distance between the first pixel region and the third pixel region.
According to claim 1 or 2,
wherein each of the first to third pixel regions has a major axis and a minor axis, and the minor axis and the major axis are parallel to the first and second directions, respectively.
According to claim 1 or 2,
wherein the groove has the same planar shape as each of the first to third pixel regions.
a substrate defining a first pixel area and second and third pixel areas respectively adjacent to the first pixel area along first and second directions;
a first electrode corresponding to each of the first to third pixel regions;
a bank covering an edge of the first electrode and positioned between the first and second pixel areas and between the first and third pixel areas;
a light emitting layer on the first electrode;
A second electrode on the light emitting layer;
A bottom of the bank is located lower than a bottom of the first electrode between the first pixel area and the second pixel area;
an insulating layer positioned under the first electrode and the bank and including a groove between the first and second pixel regions;
Each of the first to third pixel regions has a long circular shape having a major axis and a minor axis, and the groove includes a central portion and a protrusion positioned at a corner of the central portion.
According to claim 1,
The electroluminescent display device of claim 1 , wherein the depth of the center of the groove is greater than the depth of the edge of the groove in the second direction.
a substrate defining a first pixel area and second and third pixel areas respectively adjacent to the first pixel area along first and second directions;
an insulating layer positioned on the substrate and including a groove between the first and second pixel regions;
first electrodes disposed on the insulating layer and corresponding to each of the first to third pixel regions;
a bank covering an edge of the first electrode and positioned between the first and second pixel areas and between the first and third pixel areas;
a light emitting layer on the first electrode;
A second electrode on the light emitting layer;
The bank positioned between the first pixel area and the second pixel area has a first height from the first electrode, and the bank positioned between the first pixel area and the third pixel area has a height from the first electrode. Has a second height greater than the first height,
The electroluminescent display device of claim 1 , wherein the depth of the center of the groove is smaller than the depth of the edge of the groove in the second direction.
According to claim 1 or 2,
wherein the bank has the same thickness in a region between the first and second pixel regions and a region between the first and third pixel regions.
According to claim 1 or 2,
An end of the groove coincides with an end of the first electrode.
According to claim 15,
The width of the groove is the same as the distance between the first electrodes positioned in the first and second pixel areas.
forming an insulating layer on a substrate in which a first pixel area and second and third pixel areas respectively adjacent to the first pixel area along first and second directions are defined;
forming a first electrode on the insulating layer corresponding to each of the first to third pixel regions;
etching a portion of the insulating layer to form a groove between the first and second pixel regions;
forming a bank covering an edge of the first electrode and positioned between the first and second pixel areas and between the first and third pixel areas;
forming a light emitting layer on the first electrode;
Forming a second electrode on the light emitting layer,
The bank positioned between the first pixel area and the second pixel area has a first height from the first electrode, and the bank positioned between the first pixel area and the third pixel area has a height from the first electrode. Has a second height greater than the first height,
Each of the first to third pixel regions has a long circular shape having a major axis and a minor axis, and the groove includes a central portion and a protrusion positioned at a corner of the central portion.
According to claim 17,
The etching of the insulating layer is a method of manufacturing an electroluminescent display device using the first electrode as an etching mask.
According to claim 18,
An end of the groove coincides with an end of the first electrode.
According to claim 19,
The width of the groove is equal to the distance between the first electrodes positioned in the first and second pixel areas. According to claim 17,
The method of claim 1 , wherein the depth of the center of the groove is smaller than the depth of the edge of the groove in the second direction.

Images