KR20170063288A

KR20170063288A - Organic Light Emitting Diode Display Device

Info

Publication number: KR20170063288A
Application number: KR1020150169494A
Authority: KR
Inventors: 황혜민; 조윤주
Original assignee: 엘지디스플레이 주식회사
Priority date: 2015-11-30
Filing date: 2015-11-30
Publication date: 2017-06-08
Also published as: KR101776039B1

Abstract

A bank having a first electrode including a first portion and a second portion over the substrate and a transmission hole covering the second portion and exposing the first portion; Wherein the first portion and the second portion have different thicknesses, and the bank has a single structure. The organic light emitting diode display according to claim 1, . Here, the light emitting layer is formed through a solution process.

Description

[0001] The present invention relates to an organic light emitting diode (OLED) display device,

The present invention relates to an organic light emitting diode display, and more particularly to a large area and / or high resolution organic light emitting diode display.

2. Description of the Related Art Flat panel displays having excellent characteristics such as thinning, lightening, and low power consumption have been widely developed and applied to various fields.

Among the flat panel display devices, an organic light emitting diode (OLED) display device, also referred to as an organic electroluminescent display device or organic electroluminescent display device, An electron injecting charge is injected into the light emitting layer formed between the anode which is the injection electrode, and the electron and the hole are paired, and then the light is emitted while disappearing. Such an organic light emitting diode display device can be formed not only on a flexible substrate such as a plastic but also because it has a large contrast ratio and response time of several microseconds since it is a self- It is easy to manufacture and design a driving circuit because it is easy to operate, is not limited in viewing angle, is stable at a low temperature, and can be driven at a relatively low voltage of 5 V to 15 V DC.

The organic light emitting diode display device can be classified into a passive matrix type and an active matrix type according to a driving method. An active type organic light emitting diode display device capable of low power consumption, fixed size, and large size is widely used in various display devices. .

FIG. 1 is a diagram showing a structure of a general organic light emitting diode display device in a band diagram.

1, an organic light emitting diode display device includes a light emitting material layer 4 between an anode 1, which is an anode, and a cathode 7, which is an anode. . Emitting material layer 4 and between the anode 1 and the luminescent material layer 4 and between the cathode 7 and the luminescent material layer 4 to inject holes from the anode 1 and electrons from the cathode 7 into the luminescent material layer 4. [ A hole transporting layer 3 and an electron transporting layer 5 are disposed between the electron transporting layer 5 and the electron transporting layer 5, respectively. A hole injecting layer 2 is formed between the anode 1 and the hole transporting layer 3 and electrons are injected between the electron transporting layer 5 and the cathode 7 in order to more efficiently inject holes and electrons. And an electron injecting layer (6).

1, the lower line is the highest energy level of the valence band, the highest occupied molecular orbital (HOMO), the upper line is the lowest energy level of the conduction band, LUMO (lowest unoccupied molecular orbital). The energy difference between the HOMO level and the LUMO level is the band gap.

(+) Injected from the anode 1 into the light emitting material layer 4 through the hole injecting layer 2 and the hole transporting layer 3 and positive holes injected from the cathode 7 into the light emitting material layer 4 in the organic light emitting diode display device having such a structure Electrons injected into the light emitting material layer 4 through the electron injecting layer 6 and the electron transporting layer 5 are combined with each other to form an exciton 8. From this exciton 8, And emits light of a color corresponding to the band gap of the layer (4).

The light emitting material layer 4 of the organic light emitting diode display device is formed by thermal evaporation by selectively vacuum depositing an organic light emitting material using a fine metal mask. There is a problem that it is difficult to apply it to a large-area and / or high-resolution display device due to defects, shadow effects, and the like.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a large-area and / or high-resolution organic light emitting diode display device by solving the problem of vacuum deposition using a mask.

According to an aspect of the present invention, there is provided a plasma display panel comprising a substrate, a first electrode including a first portion and a second portion on the substrate, and a first electrode covering the second portion, And a second electrode on the light emitting layer, wherein the first portion and the second portion have a different thickness than the organic light emitting diode display device And the bank has a single structure.

At this time, the thickness of the first portion may be made thicker than the thickness of the second portion, or the thickness of the second portion may be made thicker than the thickness of the first portion.

Further, the upper surface of the first portion can be formed into a U-shaped curve.

In the present invention, a light emitting layer of an organic light emitting diode display device is formed by a solution process, so that it can be applied to a display device having a large area and / or a high resolution.

At this time, by forming the banks having a single structure on the first electrode including the first portion and the second portion having different thicknesses, it is possible to reduce the manufacturing time and cost by reducing the number of processes compared with the banks having the dual structure.

In addition, it is possible to reduce the amount of the solution by controlling the depth of the transmission hole of the bank, thereby reducing the material cost and improving the efficiency and lifetime of the organic light emitting diode by forming a light emitting layer having a uniform thickness.

FIG. 1 is a diagram showing a structure of a general organic light emitting diode display device in a band diagram.
2 is a schematic circuit diagram of one pixel region of an organic light emitting diode display according to an embodiment of the present invention.
3 is a cross-sectional view schematically showing an organic light emitting diode display device according to a first embodiment of the present invention.
4A to 4E are cross-sectional views schematically showing a display device in each step of the manufacturing process of the organic light emitting diode display device according to the first embodiment of the present invention.
5 is a plan view schematically showing an effective light emitting region of an organic light emitting diode display according to a first embodiment of the present invention.
FIG. 6 is a cross-sectional view schematically showing an effective light emitting region of the organic light emitting diode display according to the first embodiment of the present invention, and corresponds to line VI-VI in FIG.
7 is a plan view schematically showing an organic light emitting diode display device according to a second embodiment of the present invention.
8A to 8E are cross-sectional views schematically showing a display device in each step of the manufacturing process of the organic light emitting diode display device according to the second embodiment of the present invention.
9 is a plan view schematically showing an organic light emitting diode display device according to a third embodiment of the present invention.
10A to 10E are cross-sectional views schematically showing a display device in each step of the manufacturing process of the organic light emitting diode display device according to the third embodiment of the present invention.
11 is a plan view schematically showing an organic light emitting diode display device according to a fourth embodiment of the present invention.

An organic light emitting diode display device of the present invention includes a substrate, a first electrode including a first portion and a second portion on the substrate, and a bank having a transmission hole covering the second portion and exposing the first portion, A light emitting layer disposed on the upper portion of the first portion in the transmission hole, and a second electrode on the light emitting layer, wherein the first portion and the second portion have different thicknesses.

The thickness of the first portion may be greater than the thickness of the second portion.

At this time, the bank contacts the first portion and may include a reverse photograph side.

Alternatively, the thickness of the first portion may be less than the thickness of the second portion.

The second portion may include a side surface that is tapered adjacent the first portion, and the bank may cover the inclined side surface.

Alternatively, the upper surface of the first portion may have a U-shape.

The bank may be made of an organic insulating material having hydrophobicity.

Hereinafter, an organic light emitting diode display according to an embodiment of the present invention will be described in detail with reference to the drawings.

2 is a schematic circuit diagram of one pixel region of an organic light emitting diode display according to an embodiment of the present invention.

2, the organic light emitting diode display device according to the embodiment of the present invention includes a gate line GL and a data line DL that define a pixel region P and intersect with each other, A switching thin film transistor Ts, a driving thin film transistor Td, a storage capacitor Cst, and an organic light emitting diode De are formed in the region P.

More specifically, the gate electrode of the switching thin film transistor Ts is connected to the gate wiring GL and the source electrode thereof is connected to the data wiring DL. The gate electrode of the driving thin film transistor Td is connected to the drain electrode of the switching thin film transistor Ts, and the source electrode thereof is connected to the high potential voltage VDD. The anode of the organic light emitting diode De 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 the drain electrode of the driving thin film transistor Td.

The switching TFTs turn on according to the gate signal applied through the gate line GL and the data line DL is turned on at this time. Is applied to the gate electrode of the driving thin film transistor Td and the 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 organic light emitting diode De to display an image. The organic light emitting diode De emits light by a current of a high potential voltage (VDD) transmitted through the driving thin film transistor Td.

That is, the amount of current flowing through the organic light emitting diode De is proportional to the size of the data signal, and the intensity of light emitted by the organic light emitting diode De is proportional to the amount of current flowing through the organic light emitting diode De, The region P displays different gradations according to the size of the data signal, and as a result, the organic light emitting diode display displays an image.

The storage capacitor Cst maintains the charge corresponding to the data signal for one frame so that the amount of current flowing through the organic light emitting diode De is kept constant and the gradation displayed by the organic light emitting diode De is maintained constant .

Here, a structure in which two thin film transistors Ts and Td and one capacitor Cst are formed in one pixel region P has been described, but the number of thin film transistors and the number of capacitors are not limited thereto.

First Embodiment

FIG. 3 is a cross-sectional view schematically showing an organic light emitting diode display device according to a first embodiment of the present invention, and shows a structure corresponding to a plurality of pixel regions.

As shown in FIG. 3, a semiconductor layer 122 patterned corresponding to each pixel region is formed on an insulating substrate 110. The substrate 110 may be a glass substrate or a plastic substrate. In this case, a light shielding pattern (not shown) and a buffer layer (not shown) may be formed under the semiconductor layer 122, and the light shielding pattern may be formed on the semiconductor layer 122 And prevents the semiconductor layer 122 from being deteriorated by light. Alternatively, the semiconductor layer 122 may be made of polycrystalline silicon. In this case, impurities may be doped on both edges of the semiconductor layer 122.

A gate insulating layer 130 made of an insulating material is formed on the entire surface of the substrate 110 on the semiconductor layer 122. The gate insulating film 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 formed 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 in correspondence with the center of the semiconductor layer 122 in each pixel region. A gate line (not shown) and a first capacitor electrode (not shown) may be formed on the gate insulating layer 130. The gate wiring extends along one direction, and the first capacitor electrode is connected to the gate electrode 132. [

In the first embodiment of the present invention, the gate insulating layer 130 is formed on the entire surface of the substrate 110, but the gate insulating layer 130 may be patterned to have the same shape as the gate electrode 132.

An interlayer insulating layer 140 made of an insulating material is formed on the entire surface of the substrate 110 on 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 (SiN x) or an organic insulating material such as photo acryl or benzocyclobutene .

The interlayer insulating film 140 has first and second contact holes 140a and 140b that expose both upper surfaces 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 film 130. Alternatively, when the gate insulating film 130 is patterned to have the same shape as the gate electrode 132, the first and second contact holes 140a and 140b are formed only in the interlayer insulating film 140. [

Source and drain electrodes 152 and 154 are formed of a conductive material such as metal on the interlayer insulating layer 140 corresponding to each pixel region. A data line (not shown), a power line (not shown), and a second capacitor electrode (not shown) may be formed on the interlayer insulating layer 140.

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

On the other hand, the semiconductor layer 122, the gate electrode 132, and the source and drain electrodes 152 and 154 constitute 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, above 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 located above the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon.

Here, the thin film transistor corresponds to a driving thin film transistor of an organic light emitting diode display, 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 corresponding to each pixel region. The gate electrode 132 of the driving thin film transistor is connected to the drain electrode (not shown) of the switching thin film transistor and the source electrode 152 of the driving thin film transistor is connected to the power supply wiring (not shown). In addition, a gate electrode (not shown) and a source electrode (not shown) of the switching thin film transistor are connected to the gate wiring and the data wiring, respectively.

A protective layer 160 is formed on the entire surface of the substrate 110 as an insulating material over the source and drain electrodes 152 and 154. The protective film 160 may be formed of a silicon oxide (SiO ₂₎ or silicon nitride (SiNx) and an organic insulating material such as may be formed of an inorganic insulating material, or as benzocyclobutene, or acrylic photo. Alternatively, the protective layer 160 may include a first protective layer formed of an inorganic insulating material and a second protective layer formed of an organic insulating material.

The protective film 160 has a drain contact hole 160a for exposing the drain electrode 154. [ Here, although the drain contact hole 160a is formed directly on the second contact hole 140b, the drain contact hole 160a may be formed apart from the second contact hole 140b.

A first electrode 162 is formed on the passivation layer 160 with a conductive material having a relatively high work function. The first electrode 162 is formed for each pixel region and 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 regions and has a through hole 170a for exposing the first electrode 162 and covers the edge of the first electrode 162. [

The bank 170 includes a first bank 172 and a second bank 174 over the first bank 172. The width of the first bank 172 is larger than that of the second bank 174. [ The first bank 172 is made of a material having a relatively high surface energy and lowers the contact angle with respect to the later light layer material and the second bank 174 is made of a material having a relatively low surface energy, Thereby preventing the light emitting layer material from overflowing to adjacent pixel regions. For example, the first bank 172 may be formed of an inorganic insulating material or an organic insulating material having a hydrophilic property, and the second bank 174 may be formed of an organic insulating material having a hydrophobic property.

Alternatively, the first bank 172 and the second bank 174 may be an integral structure made of the same material. In this case, the first bank 172 and the second bank 174 may be formed of an organic insulating material having a hydrophobic property &Lt; / RTI >

A light emitting 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 an injection device including a plurality of nozzles may be used, but the present invention is not limited thereto. As an example, an inkjet printing method may be used in 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, . &Lt; / RTI > The hole-assist layer may include at least one of a hole injecting layer and a hole transporting layer. The electron-assist layer may include at least one of an electron transporting layer and an electron injecting layer. And may include at least one.

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

The luminescent material layer of each pixel region may be one of red, green and blue luminescent material layers, and one color corresponds to one pixel region.

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

The first electrode 162 and the emission layer 180 and the second electrode 192 constitute an organic light emitting diode and the first electrode 162 serves as an anode and the second electrode 192 serves as a cathode cathode.

Here, the organic light emitting diode display according to the first 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. At this time, 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. Also, the second electrode 192 may have a relatively thin thickness to transmit light, and the second electrode 192 may have a light transmittance of about 45-50%.

Alternatively, the organic light emitting diode display according to the first 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 .

A method of manufacturing the organic light emitting diode display according to the first embodiment of the present invention will be described with reference to the drawings.

4A to 4E are cross-sectional views schematically showing a display device in each step of the manufacturing process of the organic light emitting diode display device according to the first embodiment of the present invention.

4A, a semiconductor material is deposited on the insulating substrate 110 to form a semiconductor material layer (not shown), and then a semiconductor material layer is selectively removed through a photolithography process using a mask, The semiconductor layer 122 is formed.

Here, the insulating substrate 110 may be a glass substrate or a plastic substrate. In addition, the semiconductor layer 122 may be made of an oxide semiconductor material, and the oxide semiconductor material may be indium gallium zinc oxide (IGZO) or indium tin zinc oxide (ITZO) ), Indium zinc oxide (IZO), zinc oxide (ZnO), indium gallium oxide (IGO), or indium aluminum zinc oxide : IAZO). At this time, a light shielding pattern (not shown) and a buffer layer (not shown) may be further formed under the semiconductor layer 122.

Alternatively, the semiconductor layer 122 may be made of polycrystalline silicon.

Next, a gate insulating layer 130 is formed on the entire surface of the substrate 110 by depositing an insulating material on the semiconductor layer 122 by chemical vapor deposition or the like. The gate insulating film 130 may be formed of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiN x). When the semiconductor layer 122 is formed of an oxide semiconductor material, the gate insulating layer 130 is preferably formed of silicon oxide (SiO ₂ ).

Next, a conductive material such as a metal is deposited on the gate insulating layer 130 by sputtering or the like to form a first conductive material layer (not shown), and then, through a photolithography process using a mask, So that the gate electrode 132 is formed. The gate electrode 132 has a width narrower than that of the semiconductor layer 122 and is positioned corresponding to the center of the semiconductor layer 122.

The gate electrode 132 may be formed of at least one of aluminum (A), copper (Cu), molybdenum (Mo), chromium (Cr), nickel (Ni), tungsten (W)

On the other hand, a first capacitor electrode (not shown) and a gate wiring (not shown) are formed together with the gate electrode 132. Although not shown, the first capacitor electrode is connected to the gate electrode 132, and the gate wiring extends along one direction.

An interlayer insulating layer 140 is formed on the entire surface of the substrate 110 by depositing or coating an insulating material on the gate electrode 132. The interlayer insulating layer 140 and the gate insulating layer 130 Are selectively removed to form first and second contact holes 140a and 140b that expose both upper surfaces 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.

The interlayer insulating film 140 may be formed of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiN x), or may be formed of an organic insulating material such as benzocyclobutene or photo acryl .

Next, a conductive material such as metal is deposited on the interlayer insulating layer 140 by sputtering or the like to form a second conductive material layer (not shown), and then, through a photolithography process using a mask, The source and drain electrodes 152 and 154 are formed. The source and drain electrodes 152 and 154 are spaced apart from each other around the gate electrode 132 and contact with both sides of the semiconductor layer 122 through the first and second contact holes 140a and 140b.

The source and drain electrodes 152 and 154 may be formed of at least one of aluminum (Al), copper (Cu), molybdenum (Mo), chromium (Cr), nickel (Ni), tungsten .

On the other hand, a data line (not shown), a second capacitor electrode (not shown), and a power line (not shown) are formed together with the source and drain electrodes 152 and 154. Although not shown, the data wiring extends in a direction perpendicular to the gate wiring and crosses the gate wiring to define the pixel region. The second capacitor electrode is connected to the drain electrode 154, and the power supply wiring is located apart from the data wiring.

Next, a protective film 160 is formed on the entire surface of the substrate 110 by depositing or applying an insulating material on the source and drain electrodes 152 and 154, and selectively etching the protective film 160 through a photolithography process using a mask Drain contact holes 160a for exposing the drain electrodes 154 are formed. As shown, the drain contact hole 160a may be formed directly on the second contact hole 140b. Alternatively, the drain contact hole 160a may be formed apart from the second contact hole 140b.

The protective film 160 may be formed of an inorganic insulating material or an acrylic picture (photo acryl) or an organic insulating material such as benzocyclobutene (benzocyclobutene), such as silicon oxide (SiO ₂₎ or silicon nitride (SiNx).

Next, as shown in FIG. 4B, a conductive material having a relatively high work function is deposited on the passivation layer 160 by sputtering or the like to form a first electrode material layer (not shown) The first electrode material layer is selectively removed through the process to form the first electrode 162. The first electrode 162 is located in each pixel region and contacts the drain electrode 154 through the drain contact hole 160a.

The first electrode 162 may include a transparent conductive layer made of indium tin oxide (ITO) or indium zinc oxide (IZO). In addition, the first electrode 162 may further include a reflective layer, and the reflective layer may be formed of an aluminum-palladium-copper (APC) alloy. For example, the first electrode 162 may have a triple-layer structure of ITO / APC / ITO.

Next, a first bank material is deposited or applied on the first electrode 162 to form a first bank material layer (not shown) on the entire surface of the substrate 110, and a photolithography process using a mask The first bank material layer is selectively removed to form the first bank 172 between adjacent pixel regions. The first bank 172 covers the edge of the first electrode 162 and exposes the upper surface of the first electrode 162 corresponding to the pixel region. The first bank material may be an inorganic insulating material or an organic insulating material having a hydrophilic property. Next, a second bank material is applied to the top of the first bank 172 to form a second bank material layer (not shown) substantially on the entire surface of the substrate 110, and through a photolithography process using a mask, And the second bank 174 is formed on the first bank 172 by selectively removing the material layer. The second bank 174 has a narrower width than the first bank 172. The second bank material may be an organic insulating material having hydrophobic properties. Alternatively, the second bank material may be an organic insulating material having a hydrophilic property, and the surface of the second bank 174 may be subjected to a hydrophobic treatment.

Next, as shown in FIG. 4C, by injecting a light emitting material solution using an injection device (not shown) including a plurality of nozzles, a solution (solution) is formed on the exposed first electrode 162 in each of the through holes 170a Thereby forming a layer 180a.

At this time, since the second bank 174 has a hydrophobic property, even if the solution layer 180a is applied to the upper surface of the second bank 174, the solution layer 180a does not overflow into the adjacent pixel region.

Next, as shown in FIG. 4D, the solution layer (180a in FIG. 4C) is dried to form the light emitting layer 180 on the first electrode 162 in the transmission hole 170a. At this time, the solvent in the solution layer (180a in FIG. 4C) can be evaporated by performing a vacuum dry process.

Next, as shown in FIG. 4E, a second electrode 192 is formed on the entire surface of the substrate 110 by depositing a conductive material having a relatively low work function on the light emitting layer 180 by sputtering or the like. The second electrode 192 may be formed of a metal material such as aluminum, magnesium, and silver. The second electrode 192 may have a relatively thin thickness so that light is transmitted.

As described above, in the organic light emitting diode display device according to the first embodiment of the present invention, a display device having a large area and / or a high resolution can be realized by forming the light emitting layer 180 by a solution process.

In the organic light emitting diode display device according to the first embodiment of the present invention, the bank 170 may have a double structure to mitigate the file-up phenomenon of the light emitting layer 180 by the solution process.

This will be described with reference to FIGS. 5 and 6. FIG.

FIG. 5 is a plan view schematically showing an effective light emitting region of the organic light emitting diode display according to the first embodiment of the present invention. FIG. 6 is a plan view of the effective light emitting region of the organic light emitting diode display according to the first embodiment of the present invention. Sectional view taken along the line VI-VI in Fig.

5 and 6, in the organic light emitting diode display according to the first embodiment of the present invention, the bank 170 having the transmission hole 170a is formed on the first electrode 162, A light emitting layer 180 is formed on the first electrode 162 in the transmission hole 170a and a second electrode 192 is formed on the light emitting layer 180 through a solution process.

At this time, the bank 170 has a dual structure of the first bank 172 and the second bank 174, and the width of the first bank 172 is wider than the width of the second bank 174. Here, the inside of the first bank 172, that is, the region surrounded by the first bank 172 becomes the effective light emitting region EA1 in which the actual light is emitted. Also, the surface energy of the first bank 172 is relatively high and the surface energy of the second bank 174 is relatively low.

Therefore, in the first embodiment of the present invention, the thickness of the light emitting layer 180 in the pixel region can be increased by the dual structure bank 170, Up phenomenon can be alleviated.

However, in the first embodiment of the present invention, a process is added to form the bank 170 having a dual structure, thereby increasing manufacturing time and cost.

Second Embodiment

FIG. 7 is a plan view schematically illustrating an organic light emitting diode display device according to a second embodiment of the present invention, and shows the structure of an organic light emitting diode. The organic light emitting diode display device according to the second embodiment of the present invention has the same structure as that of the first embodiment except for the organic light emitting diode, and a description of the same parts will be omitted.

7, in the organic light emitting diode display device according to the second embodiment of the present invention, a switching thin film transistor (not shown), a driving thin film transistor (not shown), a storage (Not shown), a gate wiring (not shown), a data wiring (not shown), and a power wiring (not shown) are formed, and a protective film (not shown) having a flat upper surface is formed do. 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.

A first electrode 262 is formed of a conductive material having a relatively high work function on a protective film (not shown). The first electrode 262 is formed for each pixel region and is in contact with a drain electrode (not shown) of a driving thin film transistor (not shown) through a drain contact hole (not shown) of a protective film .

Here, the first electrode 262 includes a first portion 262a and a second portion 262b. The second portion 262b is located at the edge of the first portion 262a, and the first portion 262a may include an inclined side. The first portion 262a has a first thickness d11 and the second portion 262b has a second thickness d12 that is thinner than the first thickness d11.

On the first electrode 262, a bank 270 is formed of an organic insulating material. The bank 270 overlaps the second portion 262b to cover the second portion 262b and has a through hole 270a that contacts the first portion 262a and exposes the first portion 262a. The maximum thickness of the bank 270 is greater than the first thickness dl 1 of the first portion 262a and the bank 270 may include a reverse photographic side.

The bank 270 is made of a material having a relatively low surface energy, thereby increasing the contact angle with the later-formed light-emitting layer material, thereby preventing the light-emitting layer material from overflowing into the adjacent pixel region. For example, the bank 270 may be formed of an organic insulating material having a hydrophobic property.

Here, the distance between the upper surface of the first portion 262a and the upper surface of the bank 270, that is, the depth of the transmission hill 270a is smaller than the depth of the transmission hole (170a in FIG. 6) in the first embodiment. In general, the bank 270 made of an organic insulating material has a thickness of several micrometers or more and is limited in reducing its thickness, so that it is difficult to reduce the depth of the transmission hole 270a. In the second embodiment of the present invention, the depth of the transmission hole 270a can be reduced by the first portion 262a and the second portion 262b of the first electrode 262 having different thicknesses from each other.

The light emitting layer 280 is formed on the first electrode 262 exposed through the transmission hole 270a of the bank 270, more specifically, on the first portion 262a. The light emitting layer 280 is formed by a solution process, and a printing process or a coating process may be used as the solution process. For example, inkjet printing or nozzle printing may be used.

Although not shown, the light emitting layer 280 includes a hole auxiliary layer, a light-emitting material layer, and an electron auxiliary layer sequentially stacked from the top of the first electrode 262, . &Lt; / RTI > The hole-assist layer may include at least one of a hole injecting layer and a hole transporting layer. The electron-assist layer may include at least one of an electron transporting layer and an electron injecting layer. And may include at least one.

Here, the hole-assist layer and the light-emitting material layer are formed only in the transmission hole 270a, and the electron-assist layer may be formed substantially on the entire surface of the substrate 210. [ In this case, the hole-assist layer and the light-emitting material layer may be formed through a solution process, and the electron-assist layer may be formed through a vacuum deposition process.

A second electrode 292 is formed on the entire surface of the substrate 210 as a conductive material having a relatively low work function on the light emitting layer 280. Here, the second electrode 292 may be formed of aluminum, magnesium, silver, or an alloy thereof.

The first electrode 262 and the light emitting layer 280 and the second electrode 292 form an organic light emitting diode and the first electrode 262 serves as an anode and the second electrode 292 serves as a cathode cathode.

8A to 8E are cross-sectional views schematically showing a display device in each step of the manufacturing process of the organic light emitting diode display device according to the second embodiment of the present invention.

A first electrode material layer (not shown) is formed on the entire surface of the substrate 210 by depositing a conductive material having a relatively high work function on the insulating substrate 210 by sputtering or the like, The first electrode material layer is selectively removed through a photolithography process using a mask to form a first electrode 262 in a pixel region. The first electrode 262 includes a first portion 262a and a second portion 262b. The second portion 262b is located at the edge of the first portion 262a, and the first portion 262a may include an inclined side.

The second portion 262b has a thickness that is thinner than the first portion 262a. Here, the first portion 262a and the second portion 262b of the first electrode 262 are formed through a single photolithography process using a halftone mask or slit mask including a transmissive portion, a blocking portion, and a transflective portion .

For example, the first electrode material layer may be formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

4A, a switching thin film transistor (not shown), a driving thin film transistor (not shown), a storage capacitor (not shown), and a thin film transistor (not shown) are formed between the substrate 210 and the first electrode 262, A gate wiring (not shown), a data wiring (not shown), and a power wiring (not shown) are formed, and a protective film (not shown) having a flat upper surface is formed.

Next, as shown in FIG. 8B, a bank material layer is formed on the entire surface of the substrate 210 by applying a bank material on the substrate 210 including the first electrode 262, A bank material layer is selectively removed through a photolithography process using a mask to form a bank 270 between adjacent pixel regions.

At this time, the bank 270 covers the second portion 262b of the first electrode 262 and exposes the upper surface of the first portion 262a through the transmission hole 270a. The maximum thickness of the bank 270 is greater than the thickness of the first portion 262a and the side of the bank 270 in contact with the first portion 262a may be reversed. Here, the distance between the upper surface of the first portion 262a and the upper surface of the bank 270, that is, the depth of the transmission hill 270a is smaller than the depth of the transmission hole (170a in FIG. 6) in the first embodiment.

The bank material layer may comprise an organic insulating material having hydrophobic properties. Alternatively, the bank material layer may be made of an organic insulating material having a hydrophilic property, and the surface of the bank 270 may be subjected to a hydrophobic treatment.

Next, as shown in FIG. 8C, a light emitting material solution is dropped using an injection device (not shown) including a plurality of nozzles to form a first electrode 262 exposed through the transmission hole 270a A solution layer 280a is formed on the portion 262a. At this time, since the bank 270 has a hydrophobic property, even if the solution layer 280a is applied to the upper surface of the bank 270, the solution layer 280a does not overflow into the adjacent pixel region.

Here, since the depth of the penetrating hill 270a is smaller than the depth of the penetration hole (170a in FIG. 6) in the first embodiment, the amount of the light emitting material solution dropped is smaller than in the first embodiment.

Next, as shown in FIG. 8D, the solution layer (280a in FIG. 8C) is dried to form the light emitting layer 280 on the first portion 262a of the first electrode 262 in the transmission hole 270a. At this time, the solvent in the solution layer (280a in FIG. 8C) can be evaporated by performing a vacuum dry process.

At this time, since the depth of the transmission hole 270a of the bank 270 is lower than that of the first embodiment, and the bank 270 includes the reverse photograph side, The light emitting layer 280 having a uniform thickness can be formed on the first portion 262a.

Next, as shown in FIG. 8E, a second electrode 292 is formed on the entire surface of the substrate 210 by depositing a conductive material having a relatively low work function on the light emitting layer 280 by sputtering or the like. The second electrode 292 may be formed of a metal material such as aluminum, magnesium, and silver. The second electrode 292 may have a relatively thin thickness so that light is transmitted.

Since the organic light emitting diode display device according to the second embodiment of the present invention includes the banks 270 having a single structure, the number of processes is reduced as compared with the first embodiment including the banks having the dual structure (170 in FIG. 6) . Thus, manufacturing time and cost can be reduced.

It is also contemplated that the first electrode 262 may include a first portion 262a and a second portion 262b of different thicknesses and the bank 270 may include a reverse side of the photographic image and may expose the first portion 262a The depth of the transmission hole 270a of the bank 270 is lower than that of the first embodiment. Accordingly, the amount of the solution can be reduced, the material cost can be reduced, and the light emitting layer 280 having a uniform thickness can be formed on the first portion 262a.

Third Embodiment

9 is a plan view schematically illustrating an organic light emitting diode display device according to a third embodiment of the present invention, and shows the structure of an organic light emitting diode. The organic light emitting diode display device according to the third embodiment of the present invention has the same structure as that of the first embodiment except for the organic light emitting diode, and a description of the same parts will be omitted.

9, in the organic light emitting diode display according to the third embodiment of the present invention, a switching thin film transistor (not shown), a driving thin film transistor (not shown), a storage (Not shown), a gate wiring (not shown), a data wiring (not shown), and a power wiring (not shown) are formed, and a protective film (not shown) having a flat upper surface is formed do. 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.

A first electrode 362 is formed of a conductive material having a relatively high work function on a protective film (not shown). The first electrode 362 is formed in each pixel region and is in contact with a drain electrode (not shown) of a driving thin film transistor (not shown) through a drain contact hole (not shown) of a protective film (not shown) .

Here, the first electrode 362 includes a first portion 362a and a second portion 362b. The second portion 362b may be located at an edge of the first portion 362a and the second portion 362b may include an inclined side adjacent the first portion 362a. The first portion 362a has a first thickness d21 and the second portion 362b has a second thickness d22 that is thicker than the first thickness d21.

On the first electrode 362, a bank 370 is formed of an organic insulating material. The bank 370 overlaps the second portion 362b to cover the second portion 362b and has a through hole 370a that exposes the first portion 362a. The bank 370 preferably covers the inclined side surface of the second portion 362b.

The bank 370 is made of a material having a relatively low surface energy, thereby increasing the contact angle with the later-formed light-emitting layer material, thereby preventing the light-emitting layer material from overflowing into the adjacent pixel region. In one example, the bank 370 may be made of an organic insulating material having a hydrophobic property.

Here, the second portion 362b of the first electrode 362 serves as the first bank (172 of Fig. 6) in the first embodiment, and by adjusting the thickness of the second portion 362b, The distance between the upper surface of the bank 362a and the upper surface of the bank 370, that is, the depth of the transmission hull 370a, can be made equal to or larger than the depth of the transmission hole (170a in Fig. 6) in the first embodiment.

A light emitting layer 380 is formed on the first electrode 362 exposed through the transmission hole 370a of the bank 370, more specifically, on the first portion 362a. The light emitting layer 380 is formed by a solution process, and a printing process or a coating process may be used as the solution process. For example, inkjet printing or nozzle printing may be used.

Although not shown, the light emitting layer 380 includes a hole auxiliary layer, a light-emitting material layer, and an electron auxiliary layer sequentially stacked from the top of the first electrode 362, . &Lt; / RTI > The hole-assist layer may include at least one of a hole injecting layer and a hole transporting layer. The electron-assist layer may include at least one of an electron transporting layer and an electron injecting layer. And may include at least one.

Here, the hole-assist layer and the light-emitting material layer are formed only in the transmission hole 370a, and the electron-assist layer may be formed substantially on the entire surface of the substrate 310. [ In this case, the hole-assist layer and the light-emitting material layer may be formed through a solution process, and the electron-assist layer may be formed through a vacuum deposition process.

A second electrode 392 is formed on the entire surface of the substrate 310 with a conductive material having a relatively low work function on the light emitting layer 380. Here, the second electrode 392 may be formed of aluminum, magnesium, silver, or an alloy thereof.

The first electrode 362 and the emission layer 380 and the second electrode 392 form an organic light emitting diode and the first electrode 362 serves as an anode and the second electrode 392 serves as a cathode cathode.

10A to 10E are cross-sectional views schematically showing a display device in each step of the manufacturing process of the organic light emitting diode display device according to the third embodiment of the present invention.

A first electrode material layer (not shown) is formed on the entire surface of the substrate 310 by depositing a conductive material having a relatively high work function on the insulating substrate 310 by sputtering or the like, The first electrode material layer is selectively removed through a photolithography process using a mask to form a first electrode 362 in the pixel region. The first electrode 362 includes a first portion 362a and a second portion 362b. The second portion 362b may be located at an edge of the first portion 362a and the second portion 362b may comprise an inclined side.

The first portion 362a has a thickness that is thinner than the second portion 362b. Here, the first portion 362a and the second portion 362b of the first electrode 362 are formed through a single photolithography process using a halftone mask or slit mask including a transmissive portion, a blocking portion, and a transflective portion .

4A, a switching thin film transistor (not shown), a driving thin film transistor (not shown), a storage capacitor (not shown), and a second thin film transistor (not shown) are formed between the substrate 310 and the first electrode 362, A gate wiring (not shown), a data wiring (not shown), and a power wiring (not shown) are formed, and a protective film (not shown) having a flat upper surface is formed.

Next, as shown in FIG. 10B, a bank material layer is formed on the entire surface of the substrate 310 by applying a bank material on the substrate 310 including the first electrode 362, A bank material layer is selectively removed through a photolithography process using a mask to form a bank 370 between adjacent pixel regions.

At this time, the bank 370 covers the second portion 362b of the first electrode 362 and exposes the upper surface of the first portion 362a through the transmission hole 370a. The bank 370 preferably covers the inclined side surface of the second portion 362b. Here, the distance between the upper surface of the first portion 362a and the upper surface of the bank 370, that is, the depth of the transmission hull 370a is equal to the depth of the transmission hole (170a in Fig. 6) It can be big.

The bank material layer may comprise an organic insulating material having hydrophobic properties. Alternatively, the bank material layer may be made of an organic insulating material having a hydrophilic property, and the surface of the bank 370 may be subjected to a hydrophobic treatment.

Next, as shown in FIG. 10C, a light emitting material solution is dropped using an injection device (not shown) including a plurality of nozzles to form a first electrode 362 of the first electrode 362 exposed through the transmission hole 370a A solution layer 380a is formed above the portion 362a. At this time, since the bank 370 has a hydrophobic property, even if the solution layer 380a is applied to the upper surface of the bank 270, the solution layer 380a does not overflow into the adjacent pixel region.

Next, as shown in FIG. 10D, the solution layer (380a in FIG. 10C) is dried to form the light emitting layer 380 on the first portion 362a of the first electrode 362 in the transmission hole 370a. At this time, the solvent in the solution layer (380a in Fig. 10C) can be evaporated by performing a vacuum dry process.

Here, a large number of peaks may be formed on the upper surface of the first portion 362a of the first electrode 362 by etching. Such a peak is a leakage path of current. In the third portion 362a of the present invention, In the embodiment, the thickness of the light emitting layer 380 is relatively thick, so that the leakage path of the current can be cut off.

Next, as shown in FIG. 10E, a second electrode 392 is formed on the entire surface of the substrate 310 by depositing a conductive material having a relatively low work function on the light emitting layer 380 by sputtering or the like. The second electrode 392 may be formed of a metal material such as aluminum, magnesium, and silver. The second electrode 392 may have a relatively thin thickness so that light is transmitted.

In the organic light emitting diode display device according to the third embodiment of the present invention, the second portion 362b of the first electrode 362 serves as the first bank (172 of FIG. 6) in the first embodiment Since the single structure bank 370 is included, the process can be reduced as compared with the first embodiment including the bank of the dual structure (170 in FIG. 6). Thus, manufacturing time and cost can be reduced.

At this time the second portion 362b of the first electrode 362 has a sloped side adjacent to the first portion 362a so that the bank 370 covers the sloped side of the second portion 362b It is possible to prevent light from being emitted in a region other than the light emitting region.

In addition, even if a large number of peaks are formed on the upper surface of the first portion 362a of the first electrode 362 by etching, the thickness of the light emitting layer 380 is made relatively thick, so that the leakage path of the current can be cut off.

Fourth Embodiment

11 is a plan view schematically showing an organic light emitting diode display device according to a fourth embodiment of the present invention, and shows the structure of an organic light emitting diode. The organic light emitting diode display device according to the fourth embodiment of the present invention has the same structure as that of the first embodiment except for the organic light emitting diode, and illustration of the same parts will be omitted.

11, in the organic light emitting diode display device according to the fourth embodiment of the present invention, a switching thin film transistor (not shown), a driving thin film transistor (not shown), a storage (Not shown), a gate wiring (not shown), a data wiring (not shown), and a power wiring (not shown) are formed, and a protective film (not shown) having a flat upper surface is formed do. 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.

A first electrode 462 is formed of a conductive material having a relatively high work function on a protective film (not shown). The first electrode 462 is formed for each pixel region and is in contact with a drain electrode (not shown) of a driving thin film transistor (not shown) through a drain contact hole (not shown) of a protective film (not shown) .

Here, the first electrode 462 includes a first portion 462a and a second portion 462b. The upper portion of the first portion 462a is curved. The upper portion of the first portion 462a may have a U-shape, for example. have. Thus, the center of the first portion 462a has a first thickness d31, the thickness increases from the center to the edge, and the second portion 462b has a second thickness d32 that is thicker than the first thickness d31 ).

On the first electrode 462, a bank 470 is formed of an organic insulating material. The bank 470 overlaps the second portion 462b to cover the second portion 462b and has a through hole 470a that exposes the first portion 462a.

The bank 470 is made of a material having a relatively low surface energy, thereby increasing the contact angle with the later-formed light-emitting layer material, thereby preventing the light-emitting layer material from overflowing into the adjacent pixel region. In one example, the bank 470 may be made of an organic insulating material having a hydrophobic property.

Here, the second portion 462b of the first electrode 462 serves as the first bank (172 of Fig. 6) in the first embodiment, and by adjusting the thickness of the second portion 462b, The distance between the upper surface of the transmission hole 460a and the upper surface of the bank 470, that is, the depth of the transmission hull 470a can be made equal to or larger than the depth of the transmission hole (170a in FIG. 6) in the first embodiment. At this time, the maximum depth of the transmission hole 470a may be larger than the depth of the transmission hole (170a in FIG. 6) in the first embodiment.

On the other hand, the thickness of the bank 470 by the second portion 462b of the first electrode 462 may be smaller than the thickness of the first bank (174 of FIG. 6) in the first embodiment.

An emission layer 480 is formed on the first electrode 462 exposed through the transmission hole 470a of the bank 470, more specifically, on the first portion 462a. The light emitting layer 480 is formed by a solution process, and a printing process or a coating process may be used as the solution process. For example, inkjet printing or nozzle printing may be used.

In this case, the top surface of the first electrode 462 is curved so that the top surface of the light emitting layer 480 is curved. For example, the top surface of the light emitting layer 480 may have a U-shape. The top edge of the light emitting layer 480 may be lower than the light emitting layer 180 of the first embodiment (180 in Fig. 6).

Although not shown, the light emitting layer 480 includes a hole auxiliary layer, a light-emitting material layer, and an electron auxiliary layer sequentially stacked from the top of the first electrode 462, . &Lt; / RTI > The hole-assist layer may include at least one of a hole injecting layer and a hole transporting layer. The electron-assist layer may include at least one of an electron transporting layer and an electron injecting layer. And may include at least one.

Here, the hole-assist layer and the light-emitting material layer are formed only in the transmission hole 470a, and the electron-assist layer may be formed substantially on the entire surface of the substrate 410. [ In this case, the hole-assist layer and the light-emitting material layer may be formed through a solution process, and the electron-assist layer may be formed through a vacuum deposition process.

A second electrode 492 is formed on the entire surface of the substrate 410 with a conductive material having a relatively low work function on the light emitting layer 480. Here, the second electrode 492 may be formed of aluminum, magnesium, silver, or an alloy thereof.

The first electrode 462 and the light emitting layer 480 and the second electrode 492 constitute an organic light emitting diode and the first electrode 462 serves as an anode and the second electrode 492 serves as a cathode cathode.

The organic light emitting diode display device according to the fourth embodiment of the present invention can be formed by the same method as the method of manufacturing the organic light emitting diode display device according to the third embodiment shown in FIGS. 10A to 10E.

Since the organic light emitting diode display device according to the fourth embodiment of the present invention includes the banks 470 having a single structure, the number of processes can be reduced compared to the first embodiment including the banks having the dual structure (170 in FIG. 6) . Thus, manufacturing time and cost can be reduced.

Further, when the solution layer (380a in Fig. 10C) formed on the first portion (362a in Fig. 10C) of the flat first electrode (362 in Fig. 10C) is dried, as in the third embodiment, a pile-up phenomenon occurs in which the thickness of the light emitting layer (380 in FIG. 10D) becomes thicker from the center to the edge due to the coffee stain effect or the coffee ring effect. In the embodiment, the top surface of the first portion 462a of the first electrode 462 is formed in a curved shape, for example, a U-shape to improve the pile-up phenomenon to form the light emitting layer 480 having a uniform thickness .

In addition, since the thickness of the bank 470 can be made smaller than the thickness of the second bank (174 in Fig. 6) in the first embodiment, the edge of the light emitting layer 480 is the light emitting layer in the first embodiment 180, thereby reducing the amount of the solution and reducing the material cost.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined in the appended claims. And changes may be made without departing from the spirit and scope of the invention.

110: substrate 122: semiconductor layer
130: gate insulating film 132: gate electrode
140: interlayer insulating film 140a, 140b: first and second contact holes
152: source electrode 154: drain electrode
160: Protective film 160a: Drain contact hole
162: first electrode 170: bank
172: first bank 174: second bank
170a: Through hole 180: Light emitting layer
192: second electrode

Claims

Claims [1]
A first electrode comprising a first portion and a second portion on the substrate;
A bank having a transmission hole covering the second portion and exposing the first portion;
A light emitting layer located above the first portion in the transmission hole;
The second electrode
/ RTI >
Wherein the first portion and the second portion have different thicknesses.

The method according to claim 1,
Wherein the thickness of the first portion is thicker than the thickness of the second portion.

3. The method of claim 2,
Wherein the bank contacts the first portion and comprises a reverse photographic side.

The method according to claim 1,
And the thickness of the first portion is thinner than the thickness of the second portion.

5. The method of claim 4,
Wherein the second portion includes a side surface that is sloped adjacent to the first portion, and wherein the bank covers the inclined side surface.

5. The method of claim 4,
And the upper surface of the first portion has a U-shape.

7. The method according to any one of claims 1 to 6,
Wherein the bank is made of an organic insulating material having hydrophobicity.