CN100426549C - Organic light emitting display and method of manufacturing the same - Google Patents

Abstract

The present invention provides an organic light emitting display and a manufacturing method thereof. The organic light emitting display comprises: a first substrate; a first electrode arranged on the inner surface of the first substrate; an organic light emitting layer arranged on the first electrode; a second electrode arranged on the organic light emitting layer; an oxide layer formed on the second electrode; and a second substrate, wherein the second substrate is bonded to the inner surface of the first substrate to form a closed space for placing these electrodes.

Description

Organic light emitting display and manufacturing method thereof

technical field

The invention relates to an optoelectronic device, in particular to an organic light emitting display and a manufacturing method thereof.

Background technique

Generally speaking, after long-term use of organic light-emitting displays, moisture in the environment can easily penetrate into the display through the interface between the back cover and the substrate. Since the component electrodes are usually made of highly active metals, they will The water vapor infiltrated into the display reacts, and the structure of the metal layer itself is relatively loose. The water vapor will affect the light-emitting components of the lower layer through this path, causing peeling or material cracking between the metal electrode and the organic light-emitting layer, resulting in dark The generation of dark spots greatly reduces the luminous intensity and uniformity of organic light-emitting displays and reduces the life of components.

In order to prolong the service life of organic light-emitting displays, a densification treatment can be carried out on the surface of the metal electrode to make the structure of the metal layer more compact, so that the infiltration of water vapor will not affect the internal components due to the original void path, or a strong drying The agent competes with the metal electrodes to adsorb the water vapor present inside the display, so that the water vapor is absorbed before it affects the underlying components.

In addition, in order to further improve the defects of dark spots, various technologies for reducing humidity have been developed, for example, directly coating photohardening resin on the glass substrate, plating metal oxides, fluorides, sulfides, covering waterproof protective film Or adopt methods such as the manufacture of a closed back cover, but the finished product still has the disadvantages of leakage current, interference or oxide dissolution.

U.S. Patent No. 5,882,761 discloses a structure of an organic light-emitting display. As shown in FIG. 9 is composed of ultraviolet (UV) hardening glue, and is coated on the frame of the glass substrate 10. With the help of the adhesiveness of the sealant layer 9, the back cover 7 is bonded to the surface frame of the glass substrate 10 to form a sealed container.

A laminate 6 is arranged on the surface of the glass substrate 10, which is composed of an anode conductive layer 3, an organic luminescent material layer 4 and a cathode metal layer 5. layer 8, and a space 11 formed by the dry layer 8 and laminate 6 is filled with dry inert gas. Drying layer 8 is made of solid compound, such as barium oxide (BaO), calcium oxide (CaO), calcium sulfate (CaSO ₄ ) or calcium chloride (CaCl ₂ ), etc. The way is fixed in the groove of the back cover plate 7 to absorb moisture.

In the known technology of adding a drying layer 8 in the closed space of the display, if it cannot be ensured that the efficiency of the drying layer 8 absorbing moisture is better than that of the metal electrodes, then the infiltrated moisture will still react with the metal electrodes, and this will result in a drying effect. The design of the back cover 7 of the layer 8 will increase the thickness of the overall structure, which not only increases the cost but also does not conform to the current trend of light, thin, short and small flat-panel displays.

Contents of the invention

In view of this, the purpose of the present invention is to provide an organic light-emitting display, which aims to densify the metal layer structure by modifying the surface of the metal electrode, so as to ensure that water vapor will not penetrate into the light-emitting component.

In order to achieve the above object, the present invention provides an organic light emitting display structure, comprising: a first substrate; a first electrode disposed on the inner surface of the first substrate; an organic light emitting layer disposed on the first electrode ; a second electrode disposed on the organic light-emitting layer; an oxide layer formed on the second electrode; and a second substrate bonded to the inner surface of the first substrate to form a placement the enclosed space of the electrodes.

The metal electrode of the present invention undergoes a modification process to make its surface structure more dense, which fundamentally solves the problem that water vapor will enter the internal light-emitting component through the pore path, and does not need to add any desiccant design, in addition to saving device space It also greatly reduces the production cost.

The present invention also provides an organic light-emitting display structure, comprising: a substrate; a first electrode arranged on the substrate; an organic light-emitting layer arranged on the first electrode; a second electrode arranged on the organic light-emitting layer a second electrode on the top; and an oxide layer formed on the second electrode.

The light-emitting component protected by the oxide layer of the present invention can be continuously exposed to the air for hundreds of hours even without a back cover, without reducing the light-emitting area.

The present invention also provides a method for manufacturing an organic electroluminescent display, comprising the following steps: providing a substrate; disposing a first electrode on the substrate; disposing an organic light-emitting layer on the first electrode; disposing a second An electrode is on the organic light-emitting layer; and an oxygen plasma process is performed on the upper surface of the second electrode to form an oxide layer.

A feature of the present invention is to apply an oxygen plasma process that can increase the compactness of the metal electrode, so that after the water vapor penetrates into the display, it is difficult to attack the internal components again, and once the oxide layer is formed, it will prevent the surface of the metal electrode from being continuously damaged. Oxidation prolongs component life. Another feature of the present invention is that the design of eliminating the use of the dry layer can effectively reduce the internal space of the finished structure, in line with the trend of light, thin, short and small flat-panel displays.

In order to make the above-mentioned and other objects, features, and advantages of the present invention more clearly understood, the preferred embodiments are specifically listed below, and in conjunction with the accompanying drawings, the detailed description is as follows:

Description of drawings

FIG. 1 is a schematic cross-sectional view of an organic light emitting display according to US Pat. No. 5,882,761.

2 to 4 are schematic cross-sectional views of an organic light emitting display process according to a first embodiment of the present invention.

5 to 7 are schematic cross-sectional views of an organic light emitting display process according to a second embodiment of the present invention.

8 is a graph comparing brightness versus time for various display assemblies according to an embodiment of the invention.

Explanation of reference symbols:

Known part (Figure 1)

1～Organic light-emitting display;

3～anode conductive layer;

4～organic luminescent material layer;

5 ~ Cathode metal layer;

6 ~ laminates;

7 ~ back cover;

8～dry layer;

9～Sealing layer;

10 ~ glass substrate;

11 ~ interior space.

Part of the embodiment of this case (Figure 2 ~ Figure 4)

20, 50 ~ organic light-emitting display;

22, 52 ~ substrate;

24, 54 ~ sealing layer;

25, 55 ~ the first electrode;

26, 56 ~ back cover;

27, 57～organic light-emitting layer;

29, 59 ~ the second electrode;

30, 60 ~ oxide layer;

32～dry layer;

O1 ~ displays with a single oxide layer;

O2 ~ a display with two oxide layers;

S ~ Display with back cover and desiccant.

Detailed ways

Example 1

Referring to FIG. 2 , the first embodiment of the present invention, the fabrication of an organic light-emitting display, is illustrated. First, as shown in FIG. 2 , a substrate 22 is provided. Substrate 22 is a light-transmitting glass or plastic substrate, wherein the plastic substrate is made of polyethylene terephthalate (polyethyleneterephthalate), polyester (polyester), polycarbonate (polycarbonates), polyimide (polyimide) , Arton, polyacrylates (polyacrylates) or polystyrene (polystyrene) materials.

Next, a first electrode 25 is formed on the substrate 22 . The first electrode 25 is, for example, a transparent electrode, which can be indium tin oxide (ITO), indium zinc oxide (IZO), zinc aluminum oxide (AZO) or zinc oxide (ZnO).

Next, an organic light-emitting structure layer is formed on the first electrode 25. The organic light-emitting structure layer includes an electron transfer layer (not shown), an organic light-emitting layer 27, and an electromotive force transfer layer (not shown) in order from bottom to top. ), wherein the organic light-emitting layer 27 is composed of single-layer or multi-layer organic light-emitting materials, and the materials include small molecule or polymer fluorescent (fluorescence) or phosphorescent (phosphorescence) light-emitting materials. The above-mentioned small molecule organic luminescent material covering the first electrode 25 is formed by, for example, vacuum evaporation, while the polymer organic luminescent material is formed by spin coating, inkjet or screen printing.

Afterwards, a second electrode 29 is formed on the organic light-emitting layer 27. The second electrode 29 can be a single-layer or multi-layer metal electrode. The material of the metal electrode is selected from lithium, magnesium, calcium, aluminum, silver, indium, and gold. A group composed of , nickel and platinum or an alloy composed of two or more of the above elements. The fabrication of multi-layer metal electrodes can avoid the subsequent formation of oxide layers with structural defects, as shown in FIG. 3 .

Next, an oxygen plasma process is performed on the upper surface of the second electrode 29 to form a metal oxide layer 30 covering the second electrode 29 . The process conditions of the oxygen plasma process are as follows: the oxygen flow rate is generally between 10-50 sccm, preferably 30 sccm, the working temperature is generally between 20-30 degrees Celsius, preferably 25 degrees Celsius, and the working pressure is generally between Between 0.05-0.15 Torr, preferably 0.1 Torr, the working power is less than 200 watts, preferably 30 watts, and the working time is generally between 800-1000 seconds, preferably 900 seconds.

The metal oxide layer 30 is obtained by oxidizing the metal or alloy material of the second electrode 29 with oxygen plasma. The thickness of the oxide layer 30 is generally between 10-100 angstroms, preferably 50 angstroms. The configuration of the metal electrode layer 29 and the metal oxide layer 30 of the present invention includes forming a multi-layer metal layer 29 and a single-layer oxide layer 30 in addition to forming a single-layer metal layer 29 and a single-layer oxide layer 30, as shown in FIG. 3 , and forming The multi-layer metal layer 29 and the multi-layer oxide layer 30 are shown in FIG. 4 .

The fabrication of multilayer metal layer 29 and single-layer oxide layer 30 can be carried out after depositing several layers of metal layer 29, and implements an oxygen plasma process to form a metal oxide layer 30, and multilayer metal layer 29 and multilayer oxide layer 30 In the production of the present invention, between depositing each metal layer 29, oxygen plasma is applied in stages to form a situation in which multiple metal layers 29 and multiple oxide layers 30 are spaced apart. The purpose of repeatedly forming the metal layer 29 or the oxide layer 30 is to make the oxide layer 30 formed finally avoid the occurrence of defect structures.

Next, a sealant layer 24 is coated on the frame of the substrate 22 , wherein the sealant layer 24 is composed of ultraviolet (UV) hardening glue. Finally, a back cover 26 is provided, which is bonded to the surface frame of the substrate 22 by virtue of the adhesiveness of the sealant layer 24 , and then sealed into an airtight container in which the first electrode 25 , the organic light emitting layer 27 and the second electrode 29 are placed. The back cover 26 is a flat or grooved substrate, and its material can be selected from glass, polymer, ceramics or metal.

In the enclosed space formed by the substrate 22 , the back cover 26 and the sealant layer 24 , a drying layer 32 may be disposed on the inner surface of the back cover 26 . The material of the drying layer 32 can be selected from metal oxides (such as alkali metal oxides or alkaline earth oxides), metal sulfides, metal halides, metal perchlorates or highly active metal substances (such as alkali metals or alkaline earth family), etc., its thickness is less than 10 microns, preferably 1-2 microns. So far, the fabrication of an organic light emitting display 20 is completed.

Compared with the known technology, it is necessary to add a large amount of powerful desiccant to absorb moisture. The present invention uses an oxygen plasma process to improve the density of metal electrodes, so that after moisture penetrates into the display, it is difficult to attack the internal components again. Therefore, only a simple, thin desiccant is required to meet the technical requirements, and once the oxide layer is formed, it will prevent the metal electrode surface from being oxidized and prolong the life of the component.

Example 2

Referring to FIG. 5 , the first embodiment of the present invention, the fabrication of an organic light-emitting display, is illustrated. First, as shown in FIG. 5 , a substrate 52 is provided. Substrate 52 is a light-transmitting glass or plastic substrate, wherein the plastic substrate is made of polyethylene terephthalate (polyethyleneterephthalate), polyester (polyester), polycarbonate (polycarbonates), polyimide (polyimide) , Arton, polyacrylates (polyacrylates) or polystyrene (polystyrene) materials.

Next, a first electrode 55 is formed on the substrate 52 . The first electrode 55 is, for example, a transparent electrode, which can be indium tin oxide (ITO), indium zinc oxide (IZO), zinc aluminum oxide (AZO) or zinc oxide (ZnO).

Next, an organic light-emitting structure layer is formed on the first electrode 55. The organic light-emitting structure layer includes an electron transfer layer (not shown), an organic light-emitting layer 57, and an electromotive force transfer layer (not shown) in order from bottom to top. ), wherein the organic light-emitting layer 57 is composed of single-layer or multi-layer organic light-emitting materials, and the materials include small molecule or polymer fluorescent (fluorescence) or phosphorescent (phosphorescence) light-emitting materials. The above-mentioned small molecule organic luminescent material covering the first electrode 55 is formed by, for example, vacuum evaporation, while the polymer organic luminescent material is formed by spin coating, inkjet or screen printing.

After that, a second electrode 59 is formed on the organic light-emitting layer 57. The second electrode can be a single-layer or multi-layer metal electrode. The material of the metal electrode is selected from lithium, magnesium, calcium, aluminum, silver, indium, gold, A group consisting of nickel and platinum or an alloy composed of two or more of the above elements. The fabrication of multi-layer metal electrodes can avoid the subsequent formation of oxide layers with structural defects, as shown in FIG. 6 .

Next, an oxygen plasma process is performed on the upper surface of the second electrode 59 to form a metal oxide layer 60 covering the second electrode 59 . The process conditions of the oxygen plasma process are as follows: the oxygen flow rate is generally between 10-50 sccm, preferably 30 sccm, the working temperature is generally between 20-30 degrees Celsius, preferably 25 degrees Celsius, and the working pressure is generally between Between 0.05-0.15 Torr, preferably 0.1 Torr, the working power is less than 200 watts, preferably 30 watts, and the working time is generally between 800-1000 seconds, preferably 900 seconds.

The metal oxide layer 60 is obtained by oxidizing the metal or alloy material of the second electrode 59 with oxygen plasma. The thickness of the oxide layer 60 is generally between 10-100 angstroms, preferably 50 angstroms. The configuration of the metal electrode layer 59 and the metal oxide layer 60 of the present invention includes forming a multi-layer metal layer 59 and a single-layer oxide layer 60 in addition to forming a single-layer metal layer 59 and a single-layer oxide layer 60, as shown in FIG. 6 , and forming The multi-layer metal layer 59 and the multi-layer oxide layer 60 are shown in FIG. 7 .

The fabrication of the multilayer metal layer 59 and the single-layer oxide layer 60 can be performed after several layers of metal layer 59 are deposited, and an oxygen plasma process is performed to form a metal oxide layer 60, while the multilayer metal layer 59 and the multilayer oxide layer 60 In the production of the present invention, between depositing each metal layer 59, oxygen plasma is applied in stages to form a situation in which multiple metal layers 59 and multiple oxide layers 60 are spaced apart. So far, the fabrication of an organic light emitting display 50 is completed.

The light-emitting component protected by the oxide layer of the present invention can be continuously exposed to the air for hundreds of hours even without a back cover, and there will be no reduction in the light-emitting area, which will help to reduce the structure of the display The interior space is in line with its trend of being light, thin, short and small.

Next, refer to Fig. 8 to illustrate the performance of the life of each display component under long-time lighting. Fig. 8 is a graph of time versus brightness, the abscissa is the lighting time of the component (hour), and the ordinate is the brightness ratio ( Measured luminance/initial luminance), the diamond pattern (S) in the figure represents a display with a back cover and desiccant, and the triangle pattern (O ₁ ) represents a device with a single-layer oxide layer without a back cover and desiccant The square pattern (O ₂ ) represents a display with a two-layer oxide layer assembly without back cover and desiccant.

It can be seen from the figure that the lifespan of components protected by a single layer of metal oxide layer is equivalent to that of components produced by the industry standard packaging process, while the lifespan of components with two layers of metal oxide layer is better than that of standard packaging process The performance of this metal oxide layer is exposed to the environment without the protection of the back cover and desiccant. It is obvious that the effect of protecting the internal components is very good, and it can really isolate the water vapor from the outside, avoiding the impact of water vapor infiltration on the light-emitting components. , thereby prolonging its service life.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can certainly make some permissible changes and modifications without departing from the spirit and scope of the present invention. Modification, therefore, the scope of protection of the present invention should be defined by the scope of the claims.

Claims (6)

1. An organic light-emitting display, comprising: a first substrate; a first electrode disposed on the inner surface of the first substrate; an organic light-emitting layer disposed on the first electrode; a second electrode disposed on the organic light-emitting layer; a first oxide layer formed on the second electrode; a metal layer disposed on the first oxide layer; and a second oxide layer formed on the metal layer, Wherein the second electrode comprises a metal or alloy, the first oxide layer is composed of oxides of the metal or alloy of the second electrode, and the second oxide layer is composed of oxides of the metal or alloy of the metal layer . 2. The organic light emitting display as claimed in claim 1, wherein the thickness of the first or second oxide layer is between 10˜100 angstroms. 3. A method for manufacturing an organic light emitting display, comprising: providing a substrate; disposing a first electrode on the substrate; disposing an organic light-emitting layer on the first electrode; disposing a second electrode on the organic light-emitting layer; performing an oxygen plasma process on the upper surface of the second electrode to form a first oxide layer; disposing a metal layer on the first oxide layer; and performing an oxygen plasma process on the upper surface of the metal layer to form a second oxide layer, Wherein the second electrode comprises a metal or alloy, the first oxide layer is composed of oxides of the metal or alloy of the second electrode, and the second oxide layer is composed of oxides of the metal or alloy of the metal layer . 4 . The method for manufacturing an organic light emitting display as claimed in claim 3 , wherein the gas flow rate of the oxygen plasma process is between 10-50 sccm. 5. The method for manufacturing an organic light emitting display as claimed in claim 3, wherein the power of the oxygen plasma process is less than 200 watts. 6 . The method for manufacturing an organic light emitting display as claimed in claim 3 , wherein the thickness of the first or second oxide layer is between 10˜100 angstroms.

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