KR20220073371A - Electroluminescence Display - Google Patents

Abstract

This application relates to an electroluminescent display having an encapsulation layer. The electroluminescent display device according to this application includes a substrate, an anode electrode, an organic light emitting layer, a cathode electrode, nanoparticles, a first inorganic layer, an organic layer, and a second inorganic layer. The anode electrode is disposed on the substrate. The organic light emitting layer is disposed on the anode electrode. The cathode electrode is disposed on the organic light emitting layer. The nanoparticles are disposed on the cathode electrode surface. The first inorganic layer is disposed on the surface of the cathode electrode and includes a plurality of nano-protrusions covering the nanoparticles. The organic film is disposed on the first inorganic film. The second inorganic film is disposed on the organic film.

Description

Electroluminescence Display {Electroluminescence Display}

This application relates to an electroluminescent display having an encapsulation layer. In particular, this application relates to an electroluminescent display having improved protection performance of an encapsulation layer that protects an organic light emitting diode.

Recently, various types of display devices, such as a cathode ray tube (CRT), a liquid crystal display (LCD), a plasma display panel (PDP), and an electroluminescent display (Luminescent Display), have been developed and developed. Such various types of display devices are used to display image data of various products, such as computers, mobile phones, bank ATMs, and vehicle navigation systems, according to their unique characteristics.

In particular, in the case of an organic electroluminescent display, which is a self-luminous display, when foreign substances such as moisture and gas penetrate into the element from the outside, the organic element is damaged and the service life is shortened. In order to prevent this problem, a technique for applying an encapsulation layer to protect the organic light emitting device has been proposed. The configuration of the encapsulation layer may vary, but when the encapsulation layer does not completely cover the organic light emitting device, foreign substances penetrating from the outside may propagate to the organic light emitting device. Therefore, in order to completely block foreign substances, it is necessary to develop a technology for achieving a structure in which the encapsulation layer can completely cover the organic light emitting diode.

An object of this application is to overcome the problems of the prior art, and to provide an electroluminescent display device having an encapsulation layer for protecting an organic light emitting diode. In particular, the purpose is to ensure interfacial adhesion between the inorganic film and the organic film constituting the encapsulation layer to prevent voids from being generated between the inorganic film and the organic film. Another object of this application is to increase the spreadability of the organic film in the process of applying the organic film constituting the encapsulation layer, so that the organic film can be applied without voids on the surface of the lower film.

In order to achieve the above object, the electroluminescent display device according to this application includes a substrate, an anode electrode, an organic light emitting layer, a cathode electrode, nanoparticles, a first inorganic film, an organic film and a second inorganic film. The anode electrode is disposed on the substrate. The organic light emitting layer is disposed on the anode electrode. The cathode electrode is disposed on the organic light emitting layer. The nanoparticles are disposed on the cathode electrode surface. The first inorganic layer is disposed on the surface of the cathode electrode and includes a plurality of nano-protrusions covering the nanoparticles. The organic film is disposed on the first inorganic film. The second inorganic film is disposed on the organic film.

For example, nanoparticles have a ratio of width to height of 3:1. The height of the nanoparticles is 4 nm to 10 nm.

For example, nanoparticles have a ratio of width to spacing of 1:7.

For example, the cathode electrode includes silver (Ag). The nanoparticles contain silver chloride (AgCl).

For example, the nano-protrusions have a width to height ratio of 6:1. The height of the nano-protrusions is 5 nm to 12 nm.

For example, in the nano-protrusions, the ratio of the width to the spacing is 1:5.

For example, the first inorganic layer includes any one of silicon oxide, silicon nitride, and silicon oxynitride.

In one example, the anode electrode includes a first layer including a transparent oxidized conductive material, and a second layer including a reflective metal material laminated with the first layer.

For example, the anode electrode includes a light reflective material (Ag) having a thickness of 100 nm to 300 nm. The cathode electrode includes a metal material having a thickness of 15 nm to 50 nm.

In addition, the electroluminescent display device according to this application includes a substrate, an organic light emitting device, nanoparticles, a first inorganic layer, and an organic layer. The organic light emitting device includes a first electrode and a second electrode disposed on a substrate. The nanoparticles are disposed on the surface of the second electrode. The first inorganic layer is disposed on the surface of the second electrode and includes a plurality of nano-protrusions covering the nanoparticles. The organic film is disposed on the first inorganic film.

For example, the second electrode includes silver (Ag). The nanoparticles include silver chloride (AgCl) having a height of 4 nm to 10 nm. The nano-protrusions have a height of 6 nm to 12 nm.

In one example, the nanoparticles have a width of 1 to 3 times the height, and the spacing is spread at 7 times the width. The nano-protrusions have a width of 3 to 6 times the height, and the spacing is 5 times the width.

The electroluminescent display according to this application includes an encapsulation layer in which an inorganic film and an organic film are laminated on an organic light emitting element. In particular, by having a plurality of protrusions on the surface of the inorganic film, spreadability of the organic film can be improved in the process of applying the organic film. As a result, the interfacial adhesiveness between the inorganic film and the organic film is improved, and no voids are formed therebetween. Accordingly, this application can provide an electroluminescent display device having an encapsulation layer having excellent performance in blocking foreign substances penetrating from the outside.

1 is a diagram showing a schematic structure of an electroluminescent display device according to this application.
2 is a diagram showing the circuit configuration of one pixel constituting the electroluminescence display according to the present application.
3 is a plan view showing the structure of pixels according to this application.
FIG. 4 is a cross-sectional view of the electroluminescence display taken along line II-II' of FIG. 3 .
5 is a cross-sectional view illustrating the structure of the organic light emitting device and the encapsulation layer of the electroluminescent display according to this application, and is an enlarged view of the portion 'X' of FIG. 4 .

Advantages and features of this application, and a method of achieving them, will become apparent with reference to examples described below in detail in conjunction with the accompanying drawings. However, this application is not limited to the examples disclosed below, but will be implemented in various different forms, and only examples of this application allow the disclosure of the present application to be complete, and it is common in the technical field to which the invention of this application belongs. It is provided to fully inform those with knowledge of the scope of the invention, and the invention of this application is only defined by the scope of the claims.

The shape, size, ratio, angle, number, etc. disclosed in the drawings for explaining an example of this application are exemplary, and thus are not limited to the matters shown here. Like reference numerals refer to like elements throughout. In addition, in explaining the example of this application, if it is determined that the detailed description of the related known technology may unnecessarily obscure the gist of the application, the detailed description thereof will be omitted.

When 'including', 'having', 'consisting', etc. mentioned in this application specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, cases including the plural are included unless otherwise explicitly stated.

In interpreting the components, it is construed as including an error range even if there is no separate explicit description.

In the case of a description of the positional relationship, for example, when the positional relationship of two parts is described as 'on', 'on', 'on', 'beside', etc., 'right' Alternatively, one or more other parts may be positioned between two parts unless 'directly' is used.

In the case of a description of a temporal relationship, for example, 'immediately' or 'directly' when a temporal relationship is described with 'after', 'following', 'after', 'before', etc. It may include cases that are not continuous unless this is used.

Although the first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another. Accordingly, the first component mentioned below may be the second component within the technical spirit of this application.

The term “at least one” should be understood to include all possible combinations from one or more related items. For example, the meaning of “at least one of the first, second, and third items” means that each of the first, second, or third items as well as two of the first, second and third items It may mean a combination of all items that can be presented from more than one.

Each feature of the various examples of this application may be partially or wholly combined or combined with each other, technically various interlocking and driving are possible, and each example may be implemented independently of each other or may be implemented together in a related relationship. .

Hereinafter, an example of an organic light emitting diode display according to the present application will be described in detail with reference to the accompanying drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings.

Hereinafter, this application will be described in detail with reference to the accompanying drawings. 1 is a view showing a schematic structure of an electroluminescent display device according to this application. In FIG. 1 , the X axis indicates a direction parallel to the scan wiring, the Y axis indicates a direction parallel to the data wiring, and the Z axis indicates a height direction of the display device.

Referring to FIG. 1 , the electroluminescent display device according to this application includes a substrate 110 , a gate (or scan) driver 200 , a data pad unit 300 , a source driving integrated circuit 410 , and a flexible film 430 . , a circuit board 450 , and a timing controller 500 .

The substrate 110 may include an insulating material or a material having flexibility. The substrate 110 may be made of glass, metal, plastic, or the like, but is not limited thereto. When the electroluminescent display device is a flexible display device, the substrate 110 may be made of a flexible material such as plastic. For example, it may include a transparent polyimide material.

The substrate 110 may be divided into a display area DA and a non-display area NDA. The display area DA is an area where an image is displayed and may be defined in most areas including the central portion of the substrate 110 , but is not limited thereto. Scan lines (or gate lines), data lines, and pixels are formed in the display area DA. The pixels include a plurality of sub-pixels, and each of the plurality of sub-pixels includes scan lines and data lines.

The non-display area NDA is an area in which an image is not displayed, and may be defined at an edge portion of the substrate 110 to surround all or a part of the display area DA. The gate driver 200 and the data pad part 300 may be formed in the non-display area NDA.

The gate driver 200 supplies scan (or gate) signals to the scan lines according to a gate control signal input from the timing controller 500 . The gate driver 200 may be formed in a non-display area NDA outside one side of the display area DA of the base substrate 110 using a gate driver in panel (GIP) method. The GIP method refers to a structure in which the gate driver 200 is directly formed on the substrate 110 .

The data pad unit 300 supplies data signals to data lines according to a data control signal input from the timing control unit 500 . The data pad unit 300 is manufactured as a driving chip, is mounted on the flexible film 430 , and is disposed on the non-display area NDA on the outside of one side of the display area DA of the substrate 110 in a tape automated bonding (TAB) method. can be attached.

The source driving integrated circuit 410 receives digital video data and a source control signal from the timing controller 500 . The source driving integrated circuit 410 converts digital video data into analog data voltages according to a source control signal and supplies them to data lines. When the source driving integrated circuit 410 is manufactured as a chip, it may be mounted on the flexible film 430 using a chip on film (COF) or chip on plastic (COP) method.

Wires connecting the data pad unit 300 and the source driving integrated circuit 410 and wirings connecting the data pad unit 300 and the circuit board 450 may be formed on the flexible film 430 . The flexible film 430 is attached on the data pad unit 300 using an anisotropic conducting film, whereby wires of the data pad unit 300 and the flexible film 430 may be connected.

The circuit board 450 may be attached to the flexible films 430 . A plurality of circuits implemented with driving chips may be mounted on the circuit board 450 . For example, the timing controller 500 may be mounted on the circuit board 450 . The circuit board 450 may be a printed circuit board or a flexible printed circuit board.

The timing controller 500 receives digital video data and a timing signal from an external system board through a cable of the circuit board 450 . The timing controller 500 generates a gate control signal for controlling the operation timing of the gate driver 200 and a source control signal for controlling the source driving integrated circuits 410 based on the timing signal. The timing controller 500 supplies the gate control signal to the gate driver 200 and supplies the source control signal to the source driving integrated circuits 410 . Depending on the product, the timing controller 500 may be formed of the source driving integrated circuit 410 and one driving chip and mounted on the substrate 110 .

2 is a diagram illustrating a circuit configuration of one pixel constituting an electroluminescent display device according to this application. 3 is a plan view showing the structure of pixels according to this application. 4 is a cross-sectional view of the electroluminescent display taken along II-II' of FIG. 3 . 2 to 4 , an organic light emitting display device, which is a type of an electroluminescent display device, will be described as an example.

2 to 4 , one pixel of the organic light emitting diode display is defined by a scan line SL, a data line DL, and a driving current line VDD. One pixel of the organic light emitting diode display includes a switching thin film transistor ST, a driving thin film transistor DT, an organic light emitting diode OLE, and a storage capacitor Cst. A high potential voltage for driving the organic light emitting diode OLE is applied to the driving current line VDD.

For example, the switching thin film transistor ST may be disposed at a portion where the scan line SL and the data line DL intersect. The switching thin film transistor ST includes a switching gate electrode SG, a switching source electrode SS, and a switching drain electrode SD. The switching gate electrode SG is connected to the scan line SL. The switching source electrode SS is connected to the data line DL, and the switching drain electrode SD is connected to the driving thin film transistor DT. The switching thin film transistor ST functions to select a pixel to be driven by applying a data signal to the driving thin film transistor DT.

The driving thin film transistor DT serves to drive the organic light emitting diode OLE of the pixel selected by the switching thin film transistor ST. The driving thin film transistor DT includes a driving gate electrode DG, a driving source electrode DS, and a driving drain electrode DD. The driving gate electrode DG is connected to the switching drain electrode SD of the switching thin film transistor ST. The driving source electrode DS is connected to the driving current line VDD, and the driving drain electrode DD is connected to the anode electrode ANO of the organic light emitting diode OLE. The storage capacitor Cst is disposed between the driving gate electrode DG of the driving thin film transistor DT and the anode electrode ANO of the organic light emitting diode OLE.

The driving thin film transistor DT is disposed between the driving current line VDD and the organic light emitting diode OLE. The driving thin film transistor DT adjusts the amount of current flowing from the driving current line VDD to the organic light emitting diode OLE according to the magnitude of the voltage of the gate electrode connected to the drain electrode of the switching thin film transistor ST.

The organic light emitting diode OLE includes an anode electrode ANO, an organic light emitting layer OL, and a cathode electrode CAT. The organic light emitting diode OLE emits light according to a current controlled by the driving thin film transistor DT. In other words, since the amount of light emitted by the organic light emitting diode OLE is adjusted according to the current controlled by the driving thin film transistor DT, the luminance of the electroluminescence display can be adjusted. The anode electrode ANO of the organic light emitting diode OLE is connected to the driving drain electrode DD of the driving thin film transistor DT, and the cathode electrode CAT is connected to the low power supply line VSS to which a low potential voltage is supplied. do. That is, the organic light emitting diode OLE is driven by a low potential voltage and a high potential voltage regulated by the driving thin film transistor DT.

A planarization layer PL is stacked on the surface of the substrate SUB on which the thin film transistors ST and DT are formed. A contact hole exposing a portion of the drain electrode DD of the driving thin film transistor DT is formed in the planarization layer PL.

An anode electrode ANO is formed on the upper surface of the planarization layer PL. The anode electrode ANO is connected to the drain electrode DD of the driving thin film transistor DT through a contact hole. Components of the anode electrode ANO may vary depending on the light emitting structure of the organic light emitting diode OLE. For example, in the case of a bottom emission type that provides light in the direction of the substrate SUB, it may be formed of a transparent conductive material. As another example, when light is emitted in an upper direction opposite to the substrate SUB, it may be formed of a metal material having excellent light reflectance.

In the case of the top emission type, the first electrode layer 100 and the second electrode layer 200 may be stacked for the anode electrode ANO. The first electrode layer 100 is a material for matching a work function, and may include an oxidizing conductive material such as indium zinc oxide or indium tin oxide. The second electrode layer 200 is a metal material having excellent light reflectance, and includes silver (Ag), aluminum (Al), molybdenum (Mo), gold (Au), magnesium (Mg), calcium (Ca), or barium (Ba). ) may include any one material selected from or two or more alloy materials.

For example, the anode electrode (ANO) has a stacked structure of aluminum (Al) and titanium (Ti) (Ti/Al/Ti), a stacked structure of aluminum (Al) and ITO (ITO/Al/ITO), APC (Ag /Pd/Cu) alloy, and a multilayer structure such as an APC alloy and a laminate structure of ITO (ITO/APC/ITO). Alternatively, the first electrode layer 100 is made of a transparent conductive material, and the second electrode layer 200 is silver (Ag), aluminum (Al), molybdenum (Mo), gold (Au), magnesium (Mg), calcium It may be made of any one material selected from (Ca) and barium (Ba), or two or more alloy materials.

An organic light emitting layer OL is stacked on the anode electrode AN0. The organic emission layer OL is formed on the entire substrate SUB to cover the anode electrode ANO and the bank BA. The organic light emitting layer OL according to an example may include two or more light emitting units vertically stacked to emit white light. For example, the organic light emitting layer OL may include a first light emitting unit and a second light emitting unit for emitting white light by mixing the first light and the second light.

As another example, the organic light emitting layer OL may include any one of a blue light emitting unit, a green light emitting unit, and a red light emitting unit for emitting color light corresponding to a color set in the pixel. Additionally, the organic light emitting diode OLE according to an example may further include a functional layer for improving light emitting efficiency and/or lifespan of the organic light emitting layer OL.

The cathode electrode CAT is formed to be electrically connected to the organic light emitting layer OL. The cathode electrode CAT is formed over the entire substrate SUB to be commonly connected to the organic light emitting layer OL. In the case of the bottom emission type, the cathode electrode CAT includes a metal material having excellent light reflection efficiency. For example, the cathode electrode CAT may be any one selected from silver (Ag), aluminum (Al), molybdenum (Mo), gold (Au), magnesium (Mg), calcium (Ca), and barium (Ba). It may be made of a material of , or two or more alloy materials.

In the case of the top emission type, the cathode electrode CAT is preferably formed of a metal material having a relatively low sheet resistance to a thickness of less than 100 nm in order to secure light transmittance. For example, the cathode electrode CAT is preferably formed of silver (Ag) or a silver (Ag) alloy material to a thickness of 15 nm to 50 nm. When the cathode electrode (CAT) is formed with a thin silver film as described above, light is mostly transmitted without reflection. That is, most of the light emitted from the organic light emitting layer OL is reflected from the anode electrode ANO and reflected toward the cathode electrode CAT, and passes through the cathode electrode CAT to emit light in the upper direction of the substrate SUB.

A large number of nanoparticles ND are distributed on the surface of the cathode electrode CAT. Nanoparticles (ND) are particles made of silver chloride (AgCl) formed by chemical reaction by diffusing chlorine (Cl) radicals on the surface of a cathode electrode (CAT) containing silver (Ag). Since they are formed using a chemical reaction, the nanoparticles ND have a size similar to each other and are distributed on the surface of the cathode electrode CAT in a uniform distribution. In addition, the lower portion of the nanoparticles ND is in contact with the surface of the cathode electrode CAT and has a cylindrical or semicircular shape grown thereon.

An encapsulation layer EN covering both the cathode electrode CAT and the nanoparticles ND is stacked on the cathode electrode CAT. In the encapsulation layer EN, a first inorganic layer PAS1 , an organic layer PCL, and a second inorganic layer PAS2 are sequentially stacked. The first inorganic layer PAS1 may be formed of silicon oxide (SiOx), silicon nitride (SiNx), or silicon oxynitride (SiON). The first inorganic layer PAS1 may have a thickness of 0.5 μm to 1.0 μm. The organic layer PCL may be formed of an organic material such as epoxy. The organic layer PCL may have a thickness of 8 μm to 10 μm. The second inorganic layer PAS2 may be formed of silicon oxide (SiOx), silicon nitride (SiNx), or silicon oxynitride (SiON). The second inorganic layer PAS2 may have a thickness of 0.5 μm to 1.0 μm.

Specifically, the first inorganic layer PAS1 is stacked in contact with the cathode electrode CAT and the nanoparticles ND. As a result, in the first inorganic layer PAS1 , nano-protrusions PT are formed by the nanoparticles ND. The nano-protrusions PT are structures formed by the shape of the nanoparticles ND affecting the stacking profile of the first inorganic layer PAS1 .

An organic layer PCL is coated on the first inorganic layer PAS1 including the nano protrusions PT. The surface roughness of the first inorganic layer PAS1 increases due to the nano-protrusions PT. The organic layer PCL applied on the first inorganic layer PAS1 having an increased roughness has excellent spreadability, and thus is spread and applied on the first inorganic layer PAS1. That is, the organic layer PCL is completely coated without a gap between the interface between the first inorganic layer PAS1 and the organic layer PCL.

A second inorganic layer PAS2 is stacked on the organic layer PCL. As a result, the encapsulation layer EN in which the first inorganic layer PAS1 , the organic layer PCL, and the second inorganic layer PAS2 are stacked is completed. In particular, the encapsulation layer EN according to this application has a characteristic in which the organic layer PCL is completely coated on the first inorganic layer PAS1 without voids. Accordingly, the encapsulation layer EN according to this application does not float and can completely prevent foreign substances penetrating from the outside.

Hereinafter, the structures of the nanoparticles (ND) and the nano-protrusions (PT) according to this application will be described in detail with further reference to FIG. 5 . 5 is a cross-sectional view illustrating the structure of the organic light emitting device and the encapsulation layer of the electroluminescent display according to this application, and is an enlarged view of the portion 'X' of FIG. 4 . In FIG. 5 , the organic light emitting diode OLE formed on the planarization layer PL and the encapsulation layer EN covering the organic light emitting diode OLE are enlarged.

5 will be described by taking the case of the top emission type as an example. An anode electrode ANO is formed on the planarization layer PL. In the case of the top emission type, the oxide electrode layer 100 and the reflective electrode layer 200 may be stacked for the anode electrode ANO. 5 illustrates that the oxide electrode layer 100 is stacked on the lower portion, but the present invention is not limited thereto, and the reflective electrode layer 200 may be stacked on the lower portion. In the case of the top emission type, the reflective electrode layer 200 preferably has a thickness of 100 nm or more. Most preferably, it may be 200 nm or more.

An organic light emitting layer OL is stacked on the anode electrode ANO. A cathode electrode CAT is stacked on the organic light emitting layer OL. In the case of the top emission type, the cathode electrode CAT is preferably a thin film made of silver (Ag) and having a thickness of 15 nm to 50 nm. Most preferably, it may be a 30 nm silver (Ag) thin film layer.

A plurality of nanoparticles ND are dispersed on the upper surface of the cathode electrode CAT. The nanoparticles (ND) may be silver chloride (AgCl). The nanoparticles ND may be particles formed by plasma-treating chlorine (Cl) gas on the surface of the cathode electrode CAT including silver (Ag). By controlling the plasma treatment process conditions and treatment time of chlorine (Cl) gas, the size of the nanoparticles (ND) is preferably formed in a hemispherical shape with a height (H _N ) of 3 nm to 12 nm. Most preferably, the nanoparticles (ND) may have a hemispherical shape with a height (H _N ) of 4 nm to 10 nm. As another example, the nanoparticles ND may have a columnar shape with a height H _N of 6 nm to 10 nm. For example, it may have a cylindrical shape with a rounded end. The ratio of the width (W _N ) to the height (H _N ) of the nanoparticles (ND) is preferably between 4:1 and 1:1. Most preferably, the ratio of the width (W _N ) to the height (H _N ) may be 3:1.

In addition, the nanoparticles (ND) are preferably distributed so that the arrangement interval (G _N ) has 4 to 9 times the width (W _N ). Most preferably, the width W _N and the spacing G _N may have a ratio of 1:7.

A first inorganic layer PAS1 is stacked on the cathode electrode CAT and the nanoparticles ND. The first inorganic layer PAS1 includes nano-protrusions PT due to the nanoparticles ND. The nano-protrusions PT are portions protruding at a predetermined height above the surface of the first inorganic layer PAS1 . Due to the distribution of a plurality of nano-protrusions PT, the surface roughness of the first uncapped film PAS1 is increased.

The size and spacing of the nano-protrusions PT may be determined by the nanoparticles ND. Accordingly, the nano-protrusions PT may have a height of ₃ nm to 15 nm. Most preferably, it may have a size of 5 nm to 12 nm. The ratio of the width (W _P ) to the height ( _HP ) of the nano-protrusion (PT) may be between 6:1 and 1:1. The spacing G _P of the nano-protrusions PT may be 2 to 7 times the width W _P . Most preferably, the width W _P and the spacing G _P may have a ratio of 1:5.

An organic layer PCL is coated on the first inorganic layer PAS1 including the nano protrusions PT. In the case of the organic film (PCL), an organic material is mixed with a solvent to form a thin gel state, then dispersed by an ink jet process and cured by evaporating the solvent. When the organic material is included in the acid and the amount of the solvent is large, spreadability becomes too high and overflows to the outside of the display area DA, so that the organic layer PCL cannot be formed. In addition, when the amount of the solvent is small, the spreadability is too low, and micro-spreading may occur on the surface of the first inorganic layer PAS1 , resulting in voids. The air gap becomes a path through which this material can easily propagate from the outside, which can adversely affect the lifespan of the device.

Accordingly, even if the amount of the solvent for applying the organic material is small, the spreadability of the organic material may be improved by increasing the surface roughness of the first inorganic layer PAS1 . According to this application, in determining the ratio of the solvent to be administered to the organic material, even if the ratio is set so as not to overflow out of the display area DA, the nano-protrusions PT formed on the surface of the first inorganic layer PAS1 ), the spreadability of the organic material increases in the display area DA. As a result, voids due to non-spreading do not occur in the organic material, and the organic layer PCL may be formed to completely adhere to the first inorganic layer PAS1 .

Although not shown in FIG. 5 , a second inorganic layer PAS2 may be stacked on the organic layer PCL.

In this application, the nano-protrusions PT are for improving the surface roughness of the first inorganic layer PAS1 of the encapsulation layer EN. The reason for improving the surface roughness of the first inorganic layer PAS1 is to allow the organic layer PCL applied thereon to spread so that it completely adheres to the surface of the first inorganic layer PAS1 without voids. In other words, the nano-protrusions PT according to this application are for improving the adhesion of the encapsulation layer EN, rather than improving the optical properties of the organic light-emitting diode OLE.

Therefore, the nano-protrusion PT preferably has a size smaller than 100 nm. Preferably, the nano-protrusion (PT) has a size of 5 nm to 12 nm. In addition, it is preferable that the spacing (G _P ) of the nano-protrusions (PT), which determines the dispersion density, is formed to have 5 times the width (W _P ) of the nano-protrusions (PT).

For example, the nano-protrusions PT may have a hemispherical shape having a height of 10 nm and a width of 60 nm. At this time, the nano-protrusions PT are distributed five times the width W _P of the nano-protrusions PT, and the dispersion density may be 70 to 80 pieces/㎛ ² .

Improving the surface roughness by directly treating the surface of the first inorganic layer PAS1 is costly and time-consuming in consideration of a manufacturing process and material. In addition, it is very difficult to treat the surface to have a uniform surface roughness over the entire area of the display area DA.

In this application, in order to have the nano-protrusions PT without directly treating the surface of the first inorganic layer PAS1, nanoparticles ND are formed on the cathode electrode CAT. In order for the first inorganic layer PAS1 to have a desirable surface roughness, the nanoparticles ND formed on the surface of the cathode electrode CAT preferably have a size of 4 nm to 10 nm. In addition, it is preferable to form the spacing (G _N ) of the nanoparticles (ND), which determines the dispersion density, to have 7 times the width (W _N ) of the nanoparticles (ND).

For example, the nanoparticles ND may have a hemispherical shape having a height of 8 nm and a width of 45 nm. In this case, the nanoparticles ND are distributed 7 times the width W _P of the nanoparticles ND, and the dispersion density may be 70 to 80 pieces/㎛ ² . That is, since the nano-protrusions PT are formed of the nanoparticles ND, the dispersion density of the nano-protrusions PT is the same as the dispersion density of the nanoparticles ND.

Features, structures, effects, etc. described in the above-described examples of the present application are included in at least one example of the present application, and are not necessarily limited to only one example. Furthermore, features, structures, effects, etc. illustrated in at least one example of the present application may be combined or modified with respect to other examples by those of ordinary skill in the art to which the present application belongs. Accordingly, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present application.

The present application described above is not limited to the above-described embodiment and the accompanying drawings, and it is common in the technical field to which this application belongs that various substitutions, modifications and changes are possible within the scope not departing from the technical matters of the present application. It will be clear to those who have the knowledge of Therefore, the scope of the present application is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present application.

OLE: organic light emitting diode ANO: anode electrode
OL: organic light emitting layer CAT: cathode electrode
ND: Nanoparticles PT: Nano-protrusions
EN: encapsulation layer PAS1: first inorganic film
PCL: organic film PAS2: second inorganic film

Claims (12)

Board;
an anode electrode disposed on the substrate;
an organic light emitting layer disposed on the anode electrode;
a cathode electrode disposed on the organic light emitting layer;
a plurality of nanoparticles disposed on the surface of the cathode electrode;
a first inorganic film disposed on the surface of the cathode electrode and having a plurality of nano-protrusions covering the nanoparticles;
an organic layer disposed on the first inorganic layer; and
and a second inorganic layer disposed on the organic layer. The method of claim 1,
The nanoparticles are
The ratio of width to height is 3:1,
The height of the electroluminescent display device is 4 nm to 10 nm. The method of claim 1,
The nanoparticles are
An electroluminescent display device with a width to spacing ratio of 1:7. The method of claim 1,
The cathode electrode is
containing silver (Ag),
The nanoparticles are
An electroluminescent display comprising silver chloride (AgCl). The method of claim 1,
The nano-protrusions are
The ratio of width to height is 6:1,
The height of the electroluminescent display device is 6nm to 12nm. The method of claim 1,
The nano-protrusions are
An electroluminescent display device in which the ratio of width to spacing is 1:5 or more. The method of claim 1,
The first inorganic film,
An electroluminescence display comprising any one of silicon oxide, silicon nitride, and silicon oxynitride. The method of claim 1,
The anode electrode is
a first layer comprising a transparent oxidizing conductive material; and
and a second layer including a reflective metal material laminated with the first layer. The method of claim 1,
The anode electrode is
a light reflective material having a thickness of 100 nm to 300 nm;
The cathode electrode is
An electroluminescent display including a metal material having a thickness of 15 nm to 50 nm. Board;
an organic light emitting device having a first electrode and a second electrode disposed on the substrate;
a plurality of nanoparticles disposed on the surface of the second electrode;
a first inorganic film disposed on the surface of the second electrode and having a plurality of nano-protrusions covering the nanoparticles; and
and an organic layer disposed on the first inorganic layer. 11. The method of claim 10,
The second electrode is
containing silver (Ag),
The nanoparticles are
It contains silver chloride (AgCl) having a height of 4 nm to 10 nm,
The nano-protrusions are
An electroluminescent display having a height of 6 nm to 12 nm. 12. The method of claim 11,
The nanoparticles are
It has a width of 1 to 3 times the height, and the spacing is spread at 7 times the width of the nanoparticles,
The nano-protrusions are
The electroluminescent display device has a width that is 3 to 6 times the height, and the arrangement interval is 5 times the width of the nano-protrusions.

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