KR20160054720A - Organic Light Emitting Diode Display Device - Google Patents

Abstract

The present invention provides an organic light emitting diode display device. The organic light emitting diode display device includes a substrate, a first electrode in the upper part of the substrate, a first bank which covers the edge of the first electrode, has a first opening part corresponding to the first electrode, and includes a pluality of first protrusion parts so as to form an irregular part on at least one surface of the first opening part, a luminous material layer which is located in the upper part of the first electrode in the first opening part, and a second electrode in the upper part of the luminous material layer. So, the organic light emitting diode display device can obtain large area, high resolution, and uniform brightness.

Description

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

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light emitting diode display, and more particularly, to an organic light emitting diode display having improved efficiency and lifetime.

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.

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 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 high-resolution display device due to a shadow effect or the like.

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 layer surrounding the pixel region is formed, a light emitting material is injected into the bank layer using an injector, and then a light emitting material layer is formed by curing the light emitting material.

However, when a light emitting material layer is formed by a solution process, luminance unevenness occurs in a pixel, and the efficiency and life of the display device are lowered.

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 an organic light emitting diode display device having a large area, a high resolution and a uniform luminance.

It is another object of the present invention to provide an organic light emitting diode display device having improved efficiency and lifetime.

According to an aspect of the present invention, there is provided a plasma display panel comprising a substrate, a first electrode on the substrate, and a first opening covering the edge of the first electrode and corresponding to the first electrode, A first bank including a plurality of first projections so that at least one side thereof has a concavo-convex shape, a light emitting material layer located above the first electrode in the first opening, and a second electrode above the light emitting material layer And an organic light emitting diode (OLED) display device.

The adjacent first projections abut against each other.

The first projection has a triangular, rectangular, pentagonal, circular or semicircular shape in plan view.

And a second bank having a second opening above the first bank and having a width equal to or narrower than the first bank.

The second bank has a width narrower than the first bank and includes a plurality of second protrusions so that at least one side of the second opening has irregularities.

The first and second projections have a triangular, rectangular, pentagonal, circular or semicircular shape in plan view.

The first bank is made of an inorganic insulating material or an organic insulating material having a hydrophilic property, and the second bank is made of an organic insulating material having a hydrophobic property.

The present invention can be applied to a display device having a large area and a high resolution by forming a light emitting material layer of an organic light emitting diode display device by a solution process.

Further, since the surface area of the bank layer is increased by the projecting portion of the bank layer, the thickness of the light emitting material layer in the effective light emitting region can be made uniform, and the brightness in the pixel region can be made uniform.

Further, since the effective light emitting area is widened and the aperture ratio is increased, the efficiency and life of the display device can be improved.

Further, since the efficiency of the material can be improved, the material cost can be reduced.

FIG. 1 is a diagram showing a structure of a general organic light emitting diode display device in a band diagram.
2 is a circuit diagram of one pixel region of the organic light emitting diode display according to the first 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.
4 is a cross-sectional view schematically showing an effective light emitting region of an organic light emitting diode display according to a first embodiment of the present invention.
4 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.
5 is a cross-sectional 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. 6A is a plan view schematically showing an effective light emitting region of an organic light emitting diode display according to a second embodiment of the present invention. FIG. 6B and FIG. 6C are views showing an organic light emitting diode display device according to a second embodiment of the present invention. Sectional view schematically showing an effective luminescent region.
7A and 7B are a plan view schematically illustrating a first bank and a second bank of the organic light emitting diode display according to the second embodiment of the present invention, respectively.
FIG. 8A is a plan view schematically showing an effective light emitting region of the OLED display according to the third embodiment of the present invention. FIG. 8B and FIG. 8C are views showing an organic light emitting diode display device according to a third embodiment of the present invention. Sectional view schematically showing an effective luminescent region.
9A and 9B are plan views schematically illustrating a first bank and a second bank of the organic light emitting diode display according to the third embodiment of the present invention, respectively.
FIG. 10A is a plan view schematically showing an effective light emitting region of an organic light emitting diode display according to a fourth embodiment of the present invention, and FIGS. 10B and 10C are cross-sectional views illustrating an organic light emitting diode display device according to a fourth embodiment of the present invention. Sectional view schematically showing an effective luminescent region.
11A and 11B are plan views schematically showing a first bank and a second bank of the organic light emitting diode display device according to the fourth embodiment of the present invention, respectively.

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.

The organic light emitting diode display device according to an embodiment of the present invention forms a light emitting material layer by a solution process. When a light emitting material layer is formed by a solution process, the light emitting material layer may have a non- . That is, when the applied solution of the light emitting material is dried, the drying rate at the edge portion and the center portion is different, convective toward the edge portion occurs from the center portion, and the solute component accumulates along the convection. Therefore, a pile-up phenomenon occurs in which the thickness of the light emitting material layer at the edge near the bank layer becomes thicker than the center of the pixel region.

Such a file-up phenomenon causes a luminance difference at the center and the edge of the pixel region, and the efficiency and lifetime of the display apparatus are deteriorated.

- First Embodiment -

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

2, the organic light emitting diode display device according to the first embodiment of the present invention includes a gate line GL and a data line DL that define a pixel region P intersecting 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 pixel region P of the organic light emitting diode OLED.

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 .

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 one pixel region.

As shown in FIG. 3, a semiconductor layer 122 patterned on the insulating substrate 110 is formed. 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 So that the semiconductor layer 122 is prevented 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 to correspond to the center of the semiconductor layer 122. 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 the first 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 may be formed of an organic insulating material such as benzocyclobutene or photo acryl .

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 on the interlayer insulating layer 140 with a conductive material such as a metal. A data line (not shown), a power supply line (not shown), and a second capacitor electrode (not shown) may be formed on the interlayer insulating layer 140 in the second direction.

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 along the second direction and intersects the gate wiring to define the 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. 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 has a flat upper surface and 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.

The protective film 160 may be formed of an organic insulating material such as benzocyclobutene or photoacryl.

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 layer 170 is formed of an insulating material on the first electrode 162. The bank layer 170 has a transmission hole 170a for exposing the first electrode 162 and covers the edge of the first electrode 162. [

The bank layer 170 includes a first bank 172 and a second bank 174 above the first bank 172. The width of the first bank 172 is larger than the width of the second bank 174 . The first bank 172 is made of a material having a relatively high surface energy to lower the contact angle with the later-formed light-emitting layer material. The second bank 174 is made of a material having a relatively low surface energy, By increasing the contact angle, it is possible to prevent the light emitting layer material from overflowing into 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.

A light emitting material layer 180 is formed on the first electrode 162 exposed through the transmission hole 170a of the bank layer 170. [ The light emitting material layer 180 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.

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

The first electrode 162, the light emitting material layer 180 and the second electrode 192 constitute an organic light emitting diode De, and the first electrode 162 serves as an anode and the second electrode 192 serve as a 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 material layer 180 is output to the outside through the second electrode 192 have. 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 may be a bottom emission type in which light emitted from the light emitting material layer 180 is output to the outside through the first electrode 162.

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

This will be described with reference to FIG. 4 and FIG.

FIG. 4 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. 5 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. Which corresponds to the line VV in Fig.

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

At this time, the bank layer 170 has a dual structure of the first bank 172 and the second bank 174, and the width of the first bank 172 is larger than that 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 uniformity of the thickness of the light emitting material layer 180 in the pixel region can be increased by the double-structure bank layer 170, Up phenomenon of the optical disk 180 can be mitigated.

However, as shown in FIG. 5, the edge portion of the light emitting material layer 180 is thicker than the center portion in the effective light emitting region EA1, and the thickness difference still occurs in the effective light emitting region EA1, Luminance unevenness appears.

A second embodiment of the present invention for improving such luminance unevenness will be described with reference to the drawings.

- Second Embodiment -

FIG. 6A is a plan view schematically showing an effective light emitting region of an organic light emitting diode display according to a second embodiment of the present invention. FIG. 6B and FIG. 6C are views showing an organic light emitting diode display device according to a second embodiment of the present invention. Sectional view schematically showing the effective luminescent region and corresponds to VIA-VIA line and VIB-VIB line in Fig. 6A, respectively. 7A is a plan view schematically illustrating a first bank of the organic light emitting diode display according to the second embodiment of the present invention, and FIG. 7B is a cross-sectional view of the organic light emitting diode display according to the second embodiment of the present invention. 2 is a plan view schematically showing the banks. Here, the same structure as in the first embodiment is omitted, and a description thereof will be brief.

6A to 6C and FIGS. 7A and 7B, 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 thin film transistor (not shown), a storage capacitor (not shown), a gate wiring (not shown), a data wiring (not shown), and a power wiring (not shown) are formed, (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.

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 . For example, the first electrode 262 may be formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

A bank layer 270 is formed on the first electrode 262 as an insulating material. The bank layer 270 has a transmission hole 270a for exposing the first electrode 262 and covers the edge of the first electrode 262. [

The bank layer 270 includes a first bank 272 and a second bank 274 above the first bank 272. The first bank 272 is made of a material having a relatively high surface energy to lower the contact angle with respect to the later-formed light-emitting layer material. The second bank 274 is made of a material having a relatively low surface energy, By increasing the contact angle, it is possible to prevent the light emitting layer material from overflowing into adjacent pixel regions. For example, the first bank 272 may be formed of an inorganic insulating material or an organic insulating material having a hydrophilic property, and the second bank 274 may be formed of an organic insulating material having a hydrophobic property.

The first bank 272 has a first opening 272a and the second bank 274 has a second opening 274a and the first opening 272a and the second opening 274a are communicated with each other through the transmission holes 270a ). The width of the first bank 272 is wider than or equal to the width of the second bank 274 and the first bank 272 is connected to the second bank 274 so that at least one side of the first opening 272a has irregularities. And a plurality of protrusions 272b exposed by the protrusions 272b. Therefore, the area of the first bank 272 is larger than the area of the second bank 274. The first and second banks 272 and 274 are formed through respective patterning processes using a mask.

The protruding portion 272b is a quadrangular pole having a substantially rectangular shape in plan view, and having a height substantially. Referring to FIG. 7A, each of the protrusions 272b has a first length a1 and a second length a2, and is spaced apart at regular intervals. Each of the first length a1 and the second length a2 of the protrusion 272b may be greater than zero and less than or equal to 50 micrometers and preferably less than or equal to 10 micrometers. In addition, the distance between adjacent protrusions 272b may be greater than zero and less than or equal to 50 micrometers, and preferably less than or equal to 10 micrometers.

The height of the projection 272b corresponds to the thickness of the first bank 272. The thickness of the first bank 272 may be less than 1 micrometer and the thickness of the second bank 274 may be less than 3 micrometers .

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

A second electrode (not shown) is formed on the entire surface of the substrate 210 as a conductive material having a relatively low work function on the light emitting material layer 280. Here, the second electrode (not shown) may be formed of aluminum, magnesium, silver, or an alloy thereof.

The first electrode 262, the light emitting material layer 280 and the second electrode (not shown) form an organic light emitting diode. The first electrode 262 serves as an anode. The second electrode ) Serves as a cathode.

Although not shown, a hole injection layer and a hole transport layer are sequentially formed between the first electrode 262 and the light emitting material layer 280, and a hole injection layer and a hole transporting layer are sequentially formed between the light emitting material layer 280 and the second electrode An electron transport layer and an electron injection layer are sequentially formed.

In the organic light emitting diode display device according to the second embodiment of the present invention, the first bank 272 includes the protruding portion 272b, and is larger than the first bank (172 in Fig. 4) in the first embodiment Surface area. Accordingly, when the applied luminescent material solution is dried, the convection force is relatively dispersed, so that the edge portion height of the luminescent material layer 280 is lowered and the luminescent material layer 280 (EA21, EA22) Can be made more uniform.

At this time, since the remaining light emitting material solution on the surface of the second bank 274 can be collected and flow down, the material efficiency can be improved.

The first effective light emitting area EA21 is defined by the projecting part 272b of the first bank 272 and the second effective light emitting area EA22 is formed by the first bank 272 excluding the projecting part 272b. The width of the first effective light emitting area EA21 is equal to the width of the effective light emitting area EA1 in the first embodiment. Therefore, the organic light emitting diode display device according to the second embodiment of the present invention has a wider effective light emission area than the display device of the first embodiment, thereby increasing the aperture ratio.

Here, although the protruding portions 272b facing each other are shown as being on the same line, the protruding portions 272b facing each other may be located on different lines.

- Third Embodiment -

FIG. 8A is a plan view schematically showing an effective light emitting region of the OLED display according to the third embodiment of the present invention. FIG. 8B and FIG. 8C are views showing an organic light emitting diode display device according to a third embodiment of the present invention. Sectional view schematically showing the effective luminescent region, and corresponds to lines VIIIA-VIIIA and VIIIB-VIIIB in FIG. 8A, respectively. 9A is a plan view schematically showing a first bank of the organic light emitting diode display according to the third embodiment of the present invention. FIG. 9B is a cross-sectional view of the organic light emitting diode display according to the third embodiment of the present invention. 2 is a plan view schematically showing the banks. Here, the same structure as in the first embodiment is omitted, and a description thereof will be brief.

8A to 8C and FIGS. 9A and 9B, in the organic light emitting diode display according to the third embodiment of the present invention, a switching thin film transistor (not shown) A thin film transistor (not shown), a storage capacitor (not shown), a gate wiring (not shown), a data wiring (not shown), and a power wiring (not shown) are formed, (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.

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) . For example, the first electrode 362 may be formed of a transparent conductive material such as ITO or IZO.

On the first electrode 362, a bank layer 370 is formed of an insulating material. The bank layer 370 has a through hole 370a that exposes the first electrode 362 and covers the edge of the first electrode 362. [

The bank layer 370 includes a first bank 372 and a second bank 374 above the first bank 372. The first bank 372 is made of a material having a relatively high surface energy to lower the contact angle with the later-formed light-emitting layer material. The second bank 374 is made of a material having a relatively low surface energy, By increasing the contact angle, it is possible to prevent the light emitting layer material from overflowing into adjacent pixel regions. For example, the first bank 372 may be formed of an inorganic insulating material or an organic insulating material having a hydrophilic property, and the second bank 374 may be formed of an organic insulating material having a hydrophobic property.

The first bank 372 has a first opening 372a and the second bank 374 has a second opening 374a and the first opening 372a and the second opening 374a are communicated with each other through the transmission holes 370a ). The width of the first bank 372 is wider than or equal to the width of the second bank 374 and the first bank 372 is connected to the second bank 374 so that at least one side of the first opening 372a has irregularities. And a plurality of protrusions 372b exposed by the plurality of protrusions 372b. Therefore, the area of the first bank 372 is larger than the area of the second bank 374. These first and second banks 372 and 374 are formed through respective patterning processes using a mask.

The protruding portion 372b is a triangular prism having a triangular shape in a plan view and substantially a height. 9A, each of the protrusions 372b has an equilateral triangle having a first length b1 corresponding to the height of the triangle and a second length b2 corresponding to the base of the triangle, It is touching. Each of the first length b1 and the second length b2 of the protrusion 372b may be greater than zero and less than or equal to 50 micrometers and preferably less than or equal to 10 micrometers.

On the other hand, the column height of the projection 372b corresponds to the thickness of the first bank 372, the thickness of the first bank 372 is 1 micrometer or less, and the thickness of the second bank 374 is 3 micrometers or less have.

Here, the adjacent projecting portions 372b may be in contact but spaced apart. At this time, the distance between adjacent projections may be greater than zero and less than or equal to 50 micrometers, and preferably less than or equal to 10 micrometers.

A light emitting material layer 380 is formed on the first electrode 362 exposed through the transmission hole 370a of the bank layer 370. [ The light emitting material 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.

A second electrode (not shown) is formed on the entire surface of the substrate 310 as a conductive material having a relatively low work function on the light emitting material layer 380. Here, the second electrode (not shown) may be formed of aluminum, magnesium, silver, or an alloy thereof.

The first electrode 362, the emissive material layer 380, and the second electrode (not shown) form an organic light emitting diode. The first electrode 362 serves as an anode. The second electrode (not shown) Serves as a cathode.

Although not shown, a hole injection layer and a hole transport layer are sequentially formed between the first electrode 362 and the light emitting material layer 380, and a hole injection layer and a hole transporting layer are sequentially formed between the light emitting material layer 380 and the second electrode An electron transport layer and an electron injection layer are sequentially formed.

In the organic light emitting diode display device according to the third embodiment of the present invention, since the projecting portions 372b of the adjacent first banks 372 are in contact with each other, the first banks 372 (272 in FIG. 7A) And has a larger surface area. Therefore, the thickness of the light emitting material layer 380 can be made more uniform in the same effective light emitting areas EA31 and EA32 as in the second embodiment, and the aperture ratio can be further increased.

Here, although the protruding portions 372b facing each other are shown as being located on the same line, the protruding portions 372b facing each other may be located on different lines.

The protrusion 372b of the first bank 372 may have a shape other than a triangle. For example, the protrusion 372b of the first bank 372 may have a pentagon, a circular, or semicircular shape in a plan view .

- Fourth Embodiment -

FIG. 10A is a plan view schematically showing an effective light emitting region of an organic light emitting diode display according to a fourth embodiment of the present invention, and FIGS. 10B and 10C are cross-sectional views illustrating an organic light emitting diode display device according to a fourth embodiment of the present invention. Sectional view schematically showing the effective luminescent region, which corresponds to line XA-XA and line XB-XB in Fig. 10A, respectively. 11A is a plan view schematically showing a first bank of the organic light emitting diode display according to the fourth embodiment of the present invention, and FIG. 11B is a cross-sectional view of the organic light emitting diode display according to the fourth embodiment of the present invention. 2 is a plan view schematically showing the banks. Here, the same structure as in the first embodiment is omitted, and a description thereof will be brief.

10A to 10C and FIGS. 11A and 11B, in the organic light emitting diode display according to the fourth embodiment of the present invention, a switching thin film transistor (not shown) A thin film transistor (not shown), a storage capacitor (not shown), a gate wiring (not shown), a data wiring (not shown), and a power wiring (not shown) are formed, (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.

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 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) . For example, the first electrode 462 may be formed of a transparent conductive material such as ITO or IZO.

On the first electrode 462, a bank layer 470 is formed of an insulating material. The bank layer 470 has a through hole 470a that exposes the first electrode 462 and covers the edge of the first electrode 462. [

The bank layer 470 includes a first bank 472 and a second bank 474 above the first bank 472. The first bank 472 is made of a material having a relatively high surface energy to lower the contact angle with the later-formed light-emitting layer material. The second bank 474 is made of a material having a relatively low surface energy, By increasing the contact angle, it is possible to prevent the light emitting layer material from overflowing into adjacent pixel regions. For example, the first bank 472 may be formed of an inorganic insulating material or an organic insulating material having a hydrophilic property, and the second bank 474 may be formed of an organic insulating material having a hydrophobic property.

The first bank 472 has a first opening 472a and the second bank 474 has a second opening 474a and the first opening 472a and the second opening 474a are connected to the transmission holes 370a ). The width of the first bank 472 is wider than the width of the second bank 474 and the first bank 472 has a plurality of first protrusions 472b so that at least one side of the first opening 472a has concavo- And the second bank 474 includes a plurality of second projections 474b so that at least one side of the second opening 474a has a concavo-convex shape. Therefore, the area of the first bank 472 is larger than the area of the second bank 474. These first and second banks 472 and 474 are formed through respective patterning processes using a mask.

The second projection 474b has the same shape as the first projection 472b. For example, the first and second projections 472b and 474b are triangular columns having a triangular shape in a plan view and substantially a height.

11A, each of the first protrusions 472b has an equilateral triangle and has a first length c1 corresponding to the height of the triangle and a second length c2 corresponding to the base of the triangle, 472b are in contact with each other. Each of the first length c1 and the second length c2 of the first protrusion 472b may be greater than zero and less than or equal to 50 micrometers and preferably less than or equal to 10 micrometers.

11B, each of the second projections 474b has an equilateral triangle having a third length c3 corresponding to the height of the triangle and a fourth length c4 corresponding to the base of the triangle, The protrusions 474b are in contact with each other. Each of the third length c3 and the fourth length c4 of the second projection 474b may be greater than zero and less than or equal to 50 micrometers and preferably less than or equal to 10 micrometers.

The column height of the first projection 472b corresponds to the thickness of the first bank 472 and the column height of the second projection 474b corresponds to the thickness of the second bank 474. [ The thickness of the first bank 472 may be less than 1 micrometer and the thickness of the second bank 474 may be less than 3 micrometers.

Here, the adjacent first and second protrusions 472b and 474b may be in contact but may be spaced apart. At this time, the distance between adjacent projections may be greater than zero and less than or equal to 50 micrometers, and preferably less than or equal to 10 micrometers.

A light emitting material layer 480 is formed on the first electrode 462 exposed through the transmission hole 470a of the bank layer 470. The light emitting material 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.

A second electrode (not shown) is formed on the entire surface of the substrate 410 as a conductive material having a relatively low work function on the light emitting material layer 480. Here, the second electrode (not shown) may be formed of aluminum, magnesium, silver, or an alloy thereof.

The first electrode 462, the emissive material layer 480 and the second electrode (not shown) form an organic light emitting diode. The first electrode 462 serves as an anode. The second electrode (not shown) Serves as a cathode.

Although not shown, a hole injection layer and a hole transport layer are sequentially formed between the first electrode 462 and the light emitting material layer 480, and between the first electrode 462 and the light emitting material layer 480, An electron transport layer and an electron injection layer are sequentially formed.

In the organic light emitting diode display according to the fourth embodiment of the present invention, since the first and second banks 472 and 474 have the first and second protrusions 472b and 474b, respectively, (374 in Fig. 9B). Therefore, the thickness of the light emitting material layer 480 can be made more uniform in the same effective light emitting areas EA41 and EA42 as in the third embodiment, and the aperture ratio can be further increased.

Although the first projecting portion 472b and the second projecting portion 474b facing each other are shown as being disposed on the same line, the first projecting portion 472b and the second projecting portion 474b facing each other may be located on different lines .

The first and second protrusions 472b and 474b of the first and second banks 472 and 474 may have a shape other than a triangle. For example, the first and second protrusions 472b and 474b of the first and second banks 472 and 474 The first and second projections 472b and 474b may have a rectangular, pentagonal, circular or semi-circular shape in plan view.

As in the fourth embodiment, when the second bank 474 includes the protrusion 474b, the first bank 472 may be omitted.

The organic light emitting diode display according to an embodiment of the present invention may be a top emission type in which light emitted from the light emitting material layer is output to the outside through the second electrode. At this time, the first electrode 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 may have a triple-layer structure of ITO / APC / ITO. Also, the second electrode may have a relatively thin thickness through which light is transmitted, and the light transmittance of the second electrode may be about 45-50%.

Alternatively, the organic light emitting diode display may be a bottom emission type in which light emitted from the light emitting material layer is output to the outside through the first electrode.

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, 210, 310, 410: 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, 262, 362, 462: first electrode 170, 270, 370, 470: bank layer
172, 272, 372, 472: first bank 174, 274, 374, 474: second bank
272a, 372a, 472a: first openings 274a, 374a, 474a:
272b, 372b: projections 472b, 474b: first and second projections
170a, 270a, 370a, 470a: transmission holes 180, 280, 380, 480:
192: second electrode De: organic light emitting diode

Claims (7)

Claims [1]
A first electrode on the substrate;
A first bank having a first opening corresponding to the first electrode and covering an edge of the first electrode, the first bank including a plurality of first protrusions so that at least one side of the first opening has irregularities;
A light emitting material layer located above the first electrode in the first opening;
And a second electrode
And an organic light emitting diode (OLED) display device.
The method according to claim 1,
And the adjacent first protrusions are in contact with each other.
The method according to claim 1,
Wherein the first protrusion has a triangular, quadrangular, pentagonal, circular or semicircular shape in plan view.
The method according to claim 1,
Further comprising a second bank having a second opening above the first bank and having a width equal to or narrower than the first bank.
5. The method of claim 4,
Wherein the second bank has a narrower width than the first bank, and the second bank includes a plurality of second projections so that at least one side of the second opening has irregularities.
6. The method of claim 5,
Wherein the first and second protrusions have a triangular, square, pentagonal, circular or semicircular shape in plan view.
5. The method of claim 4,
Wherein the first bank is made of an inorganic insulating material or an organic insulating material having a hydrophilic property and the second bank is made of an organic insulating material having a hydrophobic property.

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