KR20140092490A - Organic Light Emitting Diode Display Device and Method for Manufacturing The Same - Google Patents

Abstract

An organic electro luminescent light emitting display device according to an aspect of the present invention includes the following: a thin film transistor formed on a substrate; an anode electrode connected to the thin film transistor; a first auxiliary electrode formed on the same layer as the anode electrode to be spaced apart from the anode electrode; a bank layer overlapping the anode electrode and a periphery of the first auxiliary electrode; a partition wall formed on the first auxiliary electrode and spaced from the bank layer; an organic light emitting layer formed on the anode electrode; a cathode electrode formed on the organic light emitting layer and electrically connected to the first auxiliary electrode; and a second auxiliary electrode formed in an area corresponding to the partition wall on the cathode electrode and electrically connected to the cathode electrode.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent display device,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting display and a method of manufacturing the same, and more particularly, to an active organic light emitting display and a method of manufacturing the same.

The cathode ray tube, which has been a leader in the display device industry for decades, has placed the top of the display device in a flat panel display with large volume and heavy weight. As compared with the cathode ray tube, which is a great advantage of high image quality, the flat panel display device can be realized as a lightweight thin type, which has attracted popularity in the display market until recently.

The flat panel display device includes a liquid crystal display (LCD), a plasma display panel (PDP), an organic light emitting diode (OLED) display, and the like. And organic electroluminescent display devices have been attracting attention as next-generation flat panel displays next to liquid crystal display devices. In particular, the organic electroluminescent display device is a self-luminous device, and it is possible to realize a light-weight thin-type device as compared with a liquid crystal display device which emits light through a backlight.

The organic electroluminescent display device has a top emission type and a bottom emission type. In the top emission type, light emitted from the organic emission layer is emitted in the direction of the cathode electrode. In the back emission emission type, light emitted from the organic emission layer is emitted toward the anode electrode. Particularly, in the case of the top surface emission type, since light is emitted through the cathode electrode, it can be formed in a thin shape, thereby increasing the resistance of the cathode electrode.

1 is a cross-sectional view illustrating a portion of a general organic light emitting display device.

1, a general organic light emitting display device includes a substrate 101, a switching transistor STR, a driving transistor DTR, a planarization layer 110, an anode electrode 120, a bank layer 130, An organic light emitting layer 140, and a cathode electrode 150.

First, a switching transistor STR and a driving transistor DTR are formed on a substrate 101. The switching transistor STR transfers the data signal received according to the scan signal to the driving transistor DTR. The driving transistor DTR transfers the power supply voltage to the anode electrode 120 by the data signal.

The anode electrode 120 is formed on the planarization layer 110 and connected to the driving transistor DTR to receive a current corresponding to the power supply voltage from the driving transistor DTR. An insulating layer (not shown) may be further formed between the planarization layer 110 and the switching transistor STR and the driving transistor DTR.

A bank layer 130 is formed on the anode electrode 120 so as to overlap the edge region of the anode electrode 120 and an organic light emitting layer 130 is formed on the anode electrode 120 that is not overlapped with the bank layer 130 and the bank layer 130. 140 may be formed. A cathode electrode 150 may be formed on the organic light emitting layer 140. The organic light emitting layer 140 may emit light in a region where the anode electrode 120 and the cathode electrode 150 are in contact with each other.

In the case of the top surface emission type, since the light emitted from the organic light emitting layer 140 is emitted through the cathode electrode 150, the thickness of the cathode electrode 150 should be thin. Since the thin cathode electrode 150 has a high resistance and current flow can be slowed down, it is necessary to lower the resistance of the cathode electrode 150 for normal driving.

An object of the present invention is to provide an organic electroluminescent display device capable of realizing a low-resistance cathode electrode.

According to an aspect of the present invention, there is provided an organic light emitting display including: a thin film transistor formed on a substrate; An anode electrode connected to the thin film transistor; A first auxiliary electrode spaced apart on the same layer as the anode electrode; A bank layer formed by overlapping an edge of the anode electrode and the first auxiliary electrode; Barrier ribs formed on the first auxiliary electrode and spaced apart from the bank layer; An organic light emitting layer formed on the anode electrode; A cathode electrode formed on the organic light emitting layer and electrically connected to the first auxiliary electrode; And a second auxiliary electrode formed in a region corresponding to the barrier rib on the cathode electrode and electrically connected to the cathode electrode.

According to another aspect of the present invention, there is provided a method of fabricating an organic light emitting display, including: forming a substrate thin film transistor; Forming a planarization film on the thin film transistor; Forming an anode electrode on the planarization film; Forming a first auxiliary electrode concurrently with the anode electrode; Forming a bank layer so as to overlap the edges of the anode electrode and the first auxiliary electrode; Forming barrier ribs on the first auxiliary electrode, the barrier ribs being spaced apart from the bank layer; Forming an organic light emitting layer on the bank layer and the barrier rib; Forming a cathode electrode electrically connected to the first auxiliary electrode on the organic light emitting layer; And forming a second auxiliary electrode on the cathode electrode.

According to the present invention, an auxiliary electrode is connected to the cathode electrode, thereby realizing a low-resistance cathode electrode.

Further, according to the present invention, the auxiliary electrode can be formed at the same time as the anode electrode, thereby improving the process efficiency.

Further, according to the present invention, an additional auxiliary electrode is further formed on the cathode electrode, thereby further reducing the resistance of the cathode electrode.

Further, according to the present invention, a low-resistance cathode electrode is realized, and luminance uniformity of a large-area organic light emitting display device can be improved.

1 is a cross-sectional view illustrating a conventional organic light emitting display device;
2 is a cross-sectional view illustrating an organic light emitting display device according to an embodiment of the present invention;
3 is a cross-sectional view illustrating an organic light emitting display device according to another embodiment of the present invention; And
4A to 4C are cross-sectional views illustrating a method of manufacturing an organic light emitting display device according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a cross-sectional view illustrating an organic light emitting display according to an exemplary embodiment of the present invention.

2, an organic light emitting display according to an exemplary embodiment of the present invention includes a substrate 201, a switching transistor STR, a driving transistor DTR, a planarization layer 210, an anode 220 A first auxiliary electrode 230, a bank layer 240, a barrier rib 250, an organic emission layer 260, a cathode electrode 270, and a second auxiliary electrode 280.

First, the substrate 201 may be formed of glass, metal, or a flexible material. The flexible material may be plastic, and may be formed of a material having excellent heat resistance and durability. For example, the substrate 201 may be formed of a material selected from the group consisting of polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylenenaphthalate (PET), polyethylene terephthalate , polyehtyleneterephthalate), and the like.

Next, the switching transistor STR and the driving transistor DTR are formed on the substrate 201. The switching transistor STR may include a gate electrode (not shown) connected to a gate line (not shown) and a source electrode (not shown) connected to a data line (not shown). The switching transistor STR may further include a drain electrode (not shown).

The data signal of the data line is transferred from the source electrode to the drain electrode by the scan signal cut at the gate line. Then, the drain electrode of the switching transistor STR is connected to the driving transistor DTR so that the data signal can be transmitted to the driving transistor DTR. The driving transistor DTR transfers the power supply voltage to the anode electrode 220 through the drain electrode (not shown) of the driving transistor DTR.

Next, a planarizing film 210 is formed on the switching transistor STR and the driving transistor DTR. The planarization layer 210 may improve the structural stability in forming the organic light emitting device formed on the upper surface by planarizing the irregularities of the switching transistor STR and the driving transistor DTR.

The planarization layer 210 may be formed of an organic material capable of planarizing the upper surface irrespective of the concavo-convex structure of the lower portion. For example, the planarization layer 210 may be formed of a photo acryl (PAC). A protective layer (not shown) formed of an inorganic material such as silicon oxide (SiOx) or silicon nitride (SiNx) may be further formed between the planarization layer 210 and the switching transistor STR and the driving transistor DTR.

Next, an anode electrode 220 is formed on the planarization film 210. The anode electrode 220 may receive a power supply voltage corresponding to a data signal from the driving transistor DTR and supply holes to the organic light emitting layer 260.

The anode electrode 220 may be formed of a material having a large work function to supply holes to the organic light emitting layer 260. The anode electrode 220 may be formed of, for example, a transparent conductive oxide, and is preferably formed of indium tin oxide (ITO), indium zinc oxide (IZO) And may be formed of Indium Tin Zinc Oxide (ITZO).

In addition, the anode electrode 220 may include a metal. The metal can improve the electrical conductivity of the anode electrode 220. The metal may include, for example, any one of silver (Ag), aluminum (Al), neodymium (Nd), copper (Cu), and molybdenum (Mo).

The anode electrode 220 may include a first metal layer 221 made of a metal and a first conductive oxide layer 222 made of a transparent conductive oxide, as shown in FIG. The first metal layer 221 may be formed on the planarization layer 210 and the first conductive oxide layer 222 may be formed on the first metal layer 221.

The first metal layer 221 may improve electrical conductivity and may serve as a reflective layer when a micro cavity structure is applied. The first conductive oxide layer 222 has a high work function and can supply holes to the organic light emitting layer 260.

The anode electrode 220 may be formed only of a conductive oxide without the first metal layer 221.

Next, a first auxiliary electrode 230 is formed on the planarization film 210. The first auxiliary electrode 230 may be spaced apart from the anode electrode 220. The first auxiliary electrode 230 may be electrically connected to the cathode electrode 270 to reduce the resistance of the cathode electrode 270.

The first auxiliary electrode 230 may be formed on the same layer as the anode electrode 220. As illustrated, the first auxiliary electrode 230 may be formed on the planarization layer 210. The first auxiliary electrode 230 may be formed of the same material as the anode 220 at the same time. The anode electrode 220 may be formed only of a conductive oxide, or may further include a metal in the conductive oxide. Similarly, the first auxiliary electrode 230 may be formed only of a conductive oxide, or may further include a metal in the conductive oxide.

The conductive oxide is preferably indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), or the like.

Examples of the metal include silver (Ag), aluminum (Al), neodymium (Nd), copper (Cu), and molybdenum (Mo).

When the anode electrode 220 is formed of a conductive oxide, the first auxiliary electrode 230 may be formed of a conductive oxide. When the anode electrode 220 is formed of the first metal layer 221 and the first conductive oxide layer 222 as shown in the drawing, the first auxiliary electrode 230 may be formed of the same material as the first metal layer 221, As shown in FIG. Since the metal is more effective at lowering the resistance than the conductive oxide, the first auxiliary electrode 230 may not include a conductive oxide. However, without being limited to the above description, the first auxiliary electrode 230 may include any one of a metal and a conductive oxide.

Next, a bank layer 240 is formed on the anode electrode 220 and the first auxiliary electrode 230. The bank layer 240 may be formed to overlap the edge regions of the anode electrode 220 and the first auxiliary electrode 230. The bank layer 240 may include any one of benzocyclobutene (BCB) series resin, acryl series resin, and polyimide resin. However, the present invention is not limited thereto.

The bank layer 240 is formed to overlap the edge of the anode electrode 220 to define a hole supplying region of the anode electrode 220, and this region can be a light emitting region. That is, the bank layer 240 may define a light emitting region.

Next, a barrier rib 250 is formed on the first auxiliary electrode 230. The bank layer 240 is formed to overlap with the edge region of the first auxiliary electrode 230 and the central portion of the first auxiliary electrode 230 may be exposed to the outside. A barrier rib 250 may be formed on the exposed first auxiliary electrode 230. The barrier ribs 250 may preferably be reverse tapered. The barrier rib 250 may prevent the organic light emitting layer 260 from being formed on the first auxiliary electrode 230.

When the organic light emitting layer 260 is formed on the first auxiliary electrode 230 in the forming order, the cathode electrode 270 can not be electrically connected to the first auxiliary electrode 230. Therefore, if the barrier rib 250 is formed on the first auxiliary electrode 230 before the organic light emitting layer 260 is formed, it is possible to prevent the organic light emitting layer 260 from being formed on the first auxiliary electrode 230 have. The cathode electrode 270 can be formed so as to be connected to the first auxiliary electrode 230 along the partition 250 so that the cathode 270 can be connected to the first auxiliary electrode 230 through the first conductive oxide layer 272, And may be electrically connected to the auxiliary electrode 230.

Next, an organic light emitting layer 260 is formed on the anode electrode 220. The organic light emitting layer 260 may be formed over the entire surface of the substrate 201 including the anode electrode 220 and over the bank layer 240 and the barrier ribs 250. The organic light emitting layer 260 is formed of an organic material, and the organic material has a low step coverage characteristic. Accordingly, the organic light emitting layer 260 may not be formed in the spaced space between the barrier ribs 250 and the bank layer 240, but may be formed between the barrier ribs 250 and the bank layer 240.

In the organic light emitting layer 260, the holes supplied from the anode electrode 220 and the electrons supplied from the cathode electrode 270 are combined to form an exciton, and then the exciton is transited to the ground state to emit light The desired gradation can be expressed for each pixel.

In the case of the RGB method in which the organic light emitting layers 260 for emitting red, green, and blue light, which are three primary colors of light, are independently formed for each pixel, the organic light emitting layer 260 of each pixel, The light of the wavelength corresponding to the color to be expressed is emitted. In the case of the WRGB system that emits white light, white light is emitted and then converted into light of a desired color through a color conversion member such as a color filter and then emitted to the outside.

Next, a cathode electrode 270 is formed on the organic light emitting layer 260. The cathode electrode 270 is preferably formed of a metal having a large number of electrons and a low work function so as to supply electrons to the organic light emitting layer 260.

Also, in the case of the upper emission type, the cathode electrode 270 may be formed of a translucent metal that can transmit light. Thus, the cathode electrode 270 may comprise a thin, semi-transparent second metal layer 271. The second metal layer 271 may include any one of silver (Ag), magnesium (Mg), calcium (Ca), and lithium (Li) 260, respectively.

The second metal layer 271 may be formed between the barrier ribs 250 and the bank layer 240 because the step coverage characteristics of the second metal layer 271 are low as in the case of the organic light emitting layer 260.

The cathode 270 may further include a second conductive oxide layer 272 formed on the second metal layer 271.

The second conductive oxide layer 272 may be in contact with the first auxiliary electrode 230. The conductive oxide includes, for example, indium tin oxide (ITO), indium zinc oxide (IZO), and indium tin zinc oxide (ITZO). These materials are excellent in step coverage characteristics and can be deposited in the form of a thin film even in a space apart from the reverse tapered barrier rib 250 and the bank layer 240. Accordingly, as shown, the conductive oxide may be deposited on the outer surface of the bank layer 240 and the barrier 250, including the cathode 270, to form the second conductive oxide layer 272. The cathode 270 can be connected to the first auxiliary electrode 230 by the second conductive oxide layer 272 so that the resistance of the cathode 270 can be lowered.

In addition, the second conductive oxide layer 272 may be formed on the second metal layer 271 to improve the transparency of the second metal layer 271. The second conductive oxide layer 272 can be connected to the first auxiliary electrode 230 as well as to the second metal layer 271 because the transparency of the metal can be somewhat improved when the metal and the conductive oxide are in contact with each other. Can also be helpful in improving the transparency of the film.

Next, a second auxiliary electrode 280 is formed on the second conductive oxide layer 272. The second auxiliary electrode 280 may be formed of a metal having a high conductivity or a low resistance and preferably includes any one of silver (Ag), copper (Cu), aluminum (Al), and neodymium Or an alloy containing any one of the above materials. The alloy may preferably be an alloy containing silver (Ag).

The second auxiliary electrode 280 is formed on the cathode electrode 270 and is formed on the cathode electrode 270 at a position corresponding to the partition 250 so that the first auxiliary electrode 230, It is possible to further reduce the resistance of the electrode 270. Since the second auxiliary electrode 280 is located at a position other than the light emitting region, the second auxiliary electrode 280 can be formed to have a sufficiently thick thickness, and the degree of design freedom for lowering the resistance is high.

3 is a cross-sectional view illustrating an organic light emitting display according to another embodiment of the present invention.

3, the organic light emitting display according to another embodiment of the present invention further includes a second auxiliary electrode 280 formed on the bank layer 240. Referring to FIG.

Since the second auxiliary electrode 280 is formed in the non-emission region of the pixel, the degree of freedom in design is high. The regions other than the light emitting region can be formed in various thicknesses. Therefore, it can be formed not only on the region corresponding to the barrier rib 250 but also on the cathode electrode 270 in the region corresponding to the bank layer 240 of the non-emission region. The second auxiliary electrode 280 may be formed between the barrier ribs 250 and the bank layer 240 because the step coverage is low.

By forming the second auxiliary electrode 280 with the largest possible area in the non-emission region as described above, a low resistance of the cathode electrode 270 can be realized. In particular, in the large organic light emitting display device, It is possible to prevent the driving deterioration caused by the light emitting element and improve the luminance uniformity.

4A to 4C are cross-sectional views illustrating a method of manufacturing an organic light emitting display according to an embodiment of the present invention.

4A, a switching transistor STR and a driving transistor DTR are formed on a substrate 201, and a drain electrode of the switching transistor STR and a gate electrode of the driving transistor DTR are electrically connected to each other So that the information of the data signal can be transmitted to the anode electrode 220.

Next, the planarization film 210 is formed on the switching transistor STR and the driving transistor DTR to flatten the irregularities of the switching transistor STR and the driving transistor DTR, The metal wiring including the transistor DTR is isolated from the organic light emitting element.

Next, a contact hole is patterned at a position corresponding to the drain electrode of the driving transistor DTR, and then an anode electrode 220 is formed on the planarization film 210. [ The anode electrode 220 may preferably include a first metal layer 221 formed on the planarization layer 210 and a first conductive oxide layer 222 formed on the first metal layer 221. The first metal layer 221 is formed on the planarization layer 210 and the first conductive layer is formed on the first metal layer 221 so as to be connected to the drain electrode of the driving transistor DTR. 222 may be formed. In some cases, the first metal layer 221 may be connected to the drain electrode of the driving transistor DTR.

Next, the first auxiliary electrode 230 is formed simultaneously with the anode electrode 220. The first auxiliary electrode 230 may include both a metal and a conductive oxide as in the anode electrode 220. The first auxiliary electrode 230 may be formed of a metal only as shown in the figure, but is not limited thereto.

The first auxiliary electrode 230 is formed in the same manner as the anode electrode 220, and thus can be formed without any additional process. The first auxiliary electrode 230 is spaced apart from the anode 220 by a predetermined distance, and may be spaced apart from the first electrode 230 such that electricity is not conducted.

Next, as shown in FIG. 4B, the bank layer 240 is partially overlapped with the anode electrode 220 and the first auxiliary electrode 230 in the edge region.

The bank layer 240 may include any one of benzocyclobutene (BCB) series resin, acryl series resin, and polyimide resin.

Next, a barrier rib 250 is formed on the first auxiliary electrode 230. The barrier rib 250 may be formed in an inverted taper shape having a taper shape. The barrier rib 250 may have a double-layer structure having different etch ratios in order to reduce the width of the lower portion contacting the first auxiliary electrode 230 to be smaller than the width of the upper portion. The barrier ribs 250 may be spaced apart from the bank layer 240 by a certain distance. The spacing distance may be such a distance that the second conductive oxide layer 272 to be formed later may be formed on the surface between the barrier ribs 250 and the bank layer 240.

Next, the organic light emitting layer 260 and the second metal layer 271 of the cathode electrode 270 are sequentially formed. The organic light emitting layer 260 may be formed on the entire surface of the substrate 201 including the anode electrode 220 and may be formed by a thermal evaporation process. At this time, the anode electrode 220 can be in contact with the bank layer 240 and the barrier rib 250. In particular, the organic light emitting layer 260 is not excellent in step coverage and can be broken at the partition 250 and the bank layer 240.

Next, a second metal layer 271 is formed on the organic light emitting layer 260. The second metal layer 271 is formed on the entire surface of the substrate 201 like the organic light emitting layer 260 and may be formed by breaking the barrier rib 250 and the bank layer 240 because the step coverage is not excellent.

Next, as shown in FIG. 4C, a second conductive oxide layer 272 is formed to cover the entire surface of the substrate 201. The second conductive oxide layer 272 may be formed by any one of a sputtering process and a thermal evaporation process. The second conductive oxide layer 272 is formed on the second metal layer 271 and is formed on the entire surface between the barrier ribs 250 and the bank layer 240. The barrier ribs 250 and the bank layers 240 And the first auxiliary electrode 230 exposed between the first auxiliary electrode 230 and the second auxiliary electrode 230. When the conductive oxide is deposited, the temperature and the deposition rate can be controlled to maximize the step coverage characteristic, so that the second conductive oxide layer 272 can be contacted with the first auxiliary electrode 230 in a maximum area.

Next, a second auxiliary electrode 280 is formed on the second conductive oxide layer 272 of the cathode electrode 270. How to form the second auxiliary electrode 280 (?). The second auxiliary electrode 280 may be electrically connected to the cathode 270 to reduce the resistance of the cathode 270. The second auxiliary electrode 280 may be formed of a metal having a high conductivity or a low resistance so that the resistance of the cathode 270 may be lowered. Preferably, the second auxiliary electrode 280 is formed of a metal such as silver (Ag), copper (Cu) ), And neodymium (Nd), or an alloy containing any one of the above materials. The alloy may preferably be an alloy containing silver (Ag).

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

201: substrate 210: planarization film
220: anode electrode 221: first metal layer
222: first conductive oxide layer 230: first auxiliary electrode
240: bank layer 250: barrier rib
260: organic light emitting layer 270: cathode electrode
271: second metal layer 272: second conductive oxide layer
STR: switching thin film transistor DTR: driving thin film transistor

Claims (12)

A thin film transistor formed on a substrate;
An anode electrode connected to the thin film transistor;
A first auxiliary electrode spaced apart on the same layer as the anode electrode;
A bank layer formed by overlapping an edge of the anode electrode and the first auxiliary electrode;
Barrier ribs formed on the first auxiliary electrode and spaced apart from the bank layer;
An organic light emitting layer formed on the anode electrode;
A cathode electrode formed on the organic light emitting layer and electrically connected to the first auxiliary electrode; And
And a second auxiliary electrode formed in a region corresponding to the barrier rib on the cathode electrode and electrically connected to the cathode electrode.
The method according to claim 1,
Wherein the anode electrode comprises a first metal layer, and the first auxiliary electrode is the same material as the first metal layer.
3. The method of claim 2,
Wherein the anode electrode further comprises a first conductive oxide layer formed on the first metal layer portion, and the first conductive oxide layer is in contact with the organic light emitting layer.
The method according to claim 1,
Wherein the barrier ribs are reverse tapered.
The method according to claim 1,
Wherein the cathode electrode includes a second metal layer, and the second metal layer is in contact with the organic light emitting layer.
6. The method of claim 5,
The cathode electrode may further include a second conductive oxide layer formed on the second metal layer, and the second conductive oxide layer may be formed to be in contact with the first auxiliary electrode inserted in the space separated from the bank layer and the bank layer Wherein the organic electroluminescent display device comprises:
The method according to claim 6,
Wherein the second auxiliary electrode is formed on the second conductive oxide layer and is in contact with the second conductive oxide layer.
Forming a thin film transistor on a substrate;
Forming a planarization film on the thin film transistor;
Forming an anode electrode on the planarization film;
Forming a first auxiliary electrode concurrently with the anode electrode;
Forming a bank layer so as to overlap the edges of the anode electrode and the first auxiliary electrode;
Forming barrier ribs on the first auxiliary electrode, the barrier ribs being spaced apart from the bank layer;
Forming an organic light emitting layer on the bank layer and the barrier rib;
Forming a cathode electrode electrically connected to the first auxiliary electrode on the organic light emitting layer; And
And forming a second auxiliary electrode on the cathode electrode.
9. The method of claim 8,
Wherein the step of forming the anode electrode comprises:
Forming a first metal layer on the planarization layer; And
Forming a first conductive oxide layer on the first metal layer; and forming a first conductive oxide layer on the first metal layer.
10. The method of claim 9,
Wherein the first auxiliary electrode is formed simultaneously with the first metal layer.
9. The method of claim 8,
The forming of the cathode electrode may include:
Forming a second metal layer on the organic light emitting layer; And
And forming a second conductive oxide on the second metal layer,
And the second auxiliary electrode is formed on the second conductive oxide.
12. The method of claim 11,
Wherein the second conductive oxide is inserted in a space where the bank layer and the barrier rib are spaced apart from each other to be in contact with the first auxiliary electrode.

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