CN1381825A - Method and structure for protecting organic electroluminescence display - Google Patents

Abstract

A method for protecting organic electroluminescent display is to cover a protection layer on the metal electrode to protect the organic electroluminescent module underneath. The protective layer is made of a metal material, and the electromotive force of the constituent element having the smallest electromotive force is smaller than that of the constituent element having the largest electromotive force of the covered metal electrode. The protective layer is a sacrificial anode of the storage battery and is used for protecting the metal electrode and the components below the metal electrode from being oxidized and deliquesced by moisture and oxygen. The organic electroluminescent display has high luminous efficiency and reliability and long service life.

Description

Method and structure for protecting organic electroluminescence display

The present invention relates to an organic electroluminescent display (organic EL display), in particular to a method for protecting an organic electroluminescent display and the structure formed therein.

At present, the manufacturing method of flat panel display applied in electronic devices has gradually adopted organic electroluminescent device (organic EL device) as the display device in the flat panel display. The structure of an organic electroluminescent component mainly includes a transparent substrate, such as a glass substrate, on which a transparent electrode layer is deposited (deposit), such as an indium tin oxide (ITO) layer, for use as an organic electroluminescence The anode of the component. An organic thin film is formed on the transparent substrate and the transparent electrode. On top of the organic thin film, a metallic electrode layer is covered, which is used as a cathode of the organic electroluminescence component. The organic thin film of the organic electroluminescence component usually includes an emitting layer (emitting layer), a hole injection layer (hole injection layer) and a hole transporting layer (hole transporting layer) sandwiched between the emitting layer and the anode, and an electron An electron injection layer and an electron transporting layer are sandwiched between the light emitting layer and the cathode.

The arrangement of the anode wires and the cathode wires of the organic electroluminescence display panel forms a two-dimensional matrix array in a staggered manner. The anode electrode is composed of several parallel strips deposited on the glass substrate, and the cathode electrode is composed of several parallel strips covering the top of the organic film and the arrangement direction of the anode electrode is staggered. Where the stripes of the anode and the stripes of the cathode intersect, it represents a pixel. Therefore, the organic electroluminescent device utilizes a two-dimensional addressable pixel array formed on a glass substrate, and after the electrons and holes are combined at the organic thin film, visible light can be generated and emitted.

Generally speaking, the cathode of an organic electroluminescent component is made of a metal material with a low work function, such as magnesium, magnesium-silver alloy, aluminum, aluminum-lithium alloy, calcium, and aluminum-calcium alloy. . However, generally speaking, metal materials with low work function are characterized by high activity and are therefore prone to oxidation and corrosion. At the same time, the materials contained in the organic light-emitting film, such as AlQ3[tris(8-quinolinolate)aluminum complex] and TPD[N,N'-diphenyl-N-N'-bis(3-methylphenyl)-1,1'-biphenyl -4,4'-diamine], which is quite sensitive to moisture and oxidation. Because there will be water vapor inside the organic electroluminescent component, and the moisture and oxygen outside the organic electroluminescent component will also invade the organic electroluminescent component, which will make the metal electrode of the organic electroluminescent component Deterioration occurs due to oxidation and deliquescence of the organic film due to the absorption of moisture. On the other hand, when an external voltage is applied to the electrodes of the organic electroluminescent device to drive the organic electroluminescent device to emit light for a period of time, the pixels of the organic electroluminescent device will generate heat. This will speed up the oxidation rate of the metal electrodes, resulting in dark spots (ie, non-luminous spots in the pixels) on the pixels of the organic electroluminescent device. With the occurrence of oxidation and deliquescence, the black spots will continue to expand, endangering an entire pixel area and weakening its luminous intensity. If the oxidation is more serious, the entire metal electrode wire of the organic electroluminescent component will be short-circuited, making a whole row of pixels unable to emit light.

In order to effectively solve the problem that organic electroluminescence components are easily degraded by moisture and oxygen, so far many people have devoted themselves to preventing the occurrence and expansion of black spots on pixels of organic electroluminescence components. Suo et al. proposed in US Patent No. 5,731,661 to cover a stable metal layer on the metal electrode of the organic electroluminescence component, such as a metal composed of indium, gold, silver, platinum and other metals with low activity. layer, which is used as a protective layer to protect the metal electrodes of the organic electroluminescence component from the intrusion of moisture and oxygen from the outside. As mentioned above, the metal electrode of the organic electroluminescent device is composed of a metal with high activity and low work function, while the material of the protective layer is low in activity, so a galvanic cell effect is formed between the two. The metal electrode of the organic electroluminescent component will become the sacrificial anode of the battery effect, and the protective layer is the cathode of the battery, so it will accelerate the deterioration of the metal electrode of the organic electroluminescent component. Therefore, if it is desired to effectively protect the metal electrodes of the organic electroluminescent component from being degraded by the intrusion of moisture and oxygen from the outside, the protective layer composed of a stable metal must completely cover the metal electrodes of the organic electroluminescent component. In order to avoid the metal electrode of the organic electroluminescent component from being more easily oxidized due to the storage battery effect. In addition, in the manufacturing process of organic electroluminescent components, when performing wet processes such as photolithography and etching to pattern pixels, the interior of organic electroluminescent components is easy to trap water. gas. However, the above protective layer can only protect the organic electroluminescent component from the intrusion of moisture and oxygen from the outside, but cannot prevent the moisture captured inside the organic electroluminescent component from invading the organic electroluminescent component. Therefore, this method cannot effectively solve the problem of moisture and oxygen intrusion caused by residual water vapor and oxygen or incomplete coating of the protective layer, resulting in deterioration of the organic electroluminescence component.

In European Patent No. 0 893 939 A1, Hirose et al. proposed another method to solve the problem of moisture and oxygen intrusion into organic electroluminescent components. Heroes et al. use the inert gas filled in the airtight encapsulation shell interior space of the organic electroluminescent display to add a kind of combustion supporting gas (combustion supporting gas) such as oxygen or chlorine, so that the metal of the organic electroluminescent component An extremely thin metal oxide layer is formed on the surface of the electrode to protect the metal electrode of the organic electroluminescence component. However, the thickness of the metal electrode of the organic electroluminescence component is quite thin, about 1500 angstroms. Therefore, when the metal oxide layer is grown, the degree of oxidation is not easy to control, and it is easy to cause over-oxidation of the metal electrode of the organic electroluminescence device, resulting in short circuit or insufficient conductivity.

In US Pat. No. 5,771,562, Harvey et al. proposed another method to solve the degradation of the metal electrodes of the organic electroluminescent device due to the intrusion of moisture and oxygen. The method proposed by Havanyi et al. is characterized in that the inner surface of the packaging shell is covered with a metal layer composed of highly active metals such as lithium or magnesium, which is used as a getter for water vapor and oxygen. ) or scavenger. However, there is a distance between the metal electrode of the organic electroluminescence component and the getter, and the space is filled with an inert gas such as nitrogen, argon or neon. Since the metal electrode of the organic electroluminescence component is far away from the metal layer used as a getter, there is no electrical conduction between the two to effectively form a galvanic connection, so it is not easy to form a battery effect. Therefore, the water vapor and oxygen inside the organic electroluminescent component will still intrude into the organic electroluminescent component, and therefore the disadvantage of water vapor and oxygen intruding into the organic electroluminescent component cannot be completely overcome.

An object of the present invention is to provide a method for manufacturing an organic electroluminescent display, which can protect the metal electrodes of the organic electroluminescent components from oxidation and corrosion.

Another object of the present invention is to provide a method for protecting an organic electroluminescent display, which can prevent the organic electroluminescent components from being oxidized and corroded by water vapor and oxygen intrusion, thereby causing black spots and short circuits in the organic electroluminescent display Shortcomings.

Another object of the present invention is to provide an organic electroluminescence display, which has better luminous efficiency, higher reliability and longer lifespan.

In order to achieve the above object, the method for manufacturing an organic electroluminescence display according to one aspect of the present invention is characterized in that the method includes the following steps: forming a first electrode layer on a substrate; forming a first electrode layer above the first electrode layer An organic layer; a second electrode layer is formed above the organic layer, the second electrode layer and the first electrode layer form a staggered pixel matrix array, wherein the substrate, the first electrode layer, The organic layer and the second electrode layer form an organic electroluminescent component; a protective layer is covered on a part of the second electrode layer, wherein the constituent elements of the protective layer have the minimum electromotive force (electromotive force) a constituent element of force), whose electromotive force is smaller than an electromotive force of a constituent element having the largest electromotive force among the constituent elements of the second electrode layer, so as to protect the organic electroluminescence component from the intrusion of water vapor and oxygen; And encapsulating the organic electroluminescent component with an airtight casing, so as to isolate the organic electroluminescent component from the outside air and moisture.

The substrate includes a transparent substrate, such as soda lime glass (soda lime), borosilicate glass (borosilicate) or alkali-free glass (alkali free). The first electrode layer is composed of a transparent conductive material, such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc aluminum oxide (AZO) or zinc oxide (ZnO), and the The first electrode layer is deposited on the substrate by sputtering deposition, ion plating deposition or electron beam deposition.

The organic layer is formed by an evaporation method, and the second electrode layer of the organic electroluminescence component is composed of a metal material, and is formed by an evaporation method or an electron beam evaporation method or sputtering Formed by deposition. The protection layer is also made of a metal material, and is deposited on the second electrode layer of the organic electroluminescence component by means of evaporation, electron beam evaporation or sputtering.

Preferably, the packaging shell is composed of a metal plate or a glass plate, and the organic electroluminescent component is packaged by combining a packaging medium with the glass plate of the organic electroluminescent component. Generally, the encapsulation medium is composed of an epoxy. After the organic electroluminescent component is hermetically sealed in an airtight package, a dry inert gas such as nitrogen, argon or neon is filled in the inner space of the package to reduce the airtight space inside the package. moisture and oxygen content.

To achieve the above object, according to another aspect of the present invention, a method for protecting an organic electroluminescent display is characterized in that the method includes the following steps: providing an organic electroluminescent component, wherein the organic electroluminescent component It includes a substrate, a first electrode layer is formed on the substrate, an organic layer is formed on the first electrode layer, and a second electrode layer is formed on the organic layer and is connected with the first electrode layer. An electrode layer forms a staggered pixel matrix array; a protective layer is covered on a part of the second electrode layer, wherein, among the constituent elements of the protective layer, a constituent element with the smallest electromotive force is less than The electromotive force of the constituent element having one of the largest electromotive force among the constituent elements of the second electrode layer is used to protect the organic electroluminescence component from the intrusion of water vapor and oxygen; and encapsulate the The organic electroluminescent component is used to isolate the organic electroluminescent component from the air and moisture outside.

Preferably, the second electrode layer of the organic electroluminescent component and the protective layer used to protect the organic electroluminescent component are both composed of a metal material, and are deposited by evaporation or electron beam evaporation. or deposited by sputtering. On the other hand, the packaging shell is composed of a metal plate or a glass plate, and the organic electroluminescent component is packaged by combining a packaging medium with the glass plate of the organic electroluminescent component. Generally, the encapsulation medium is composed of an epoxy. After the organic electroluminescent component is hermetically sealed in an airtight package, a dry inert gas such as nitrogen, argon or neon is filled in the inner space of the package to reduce the airtight space inside the package. moisture and oxygen content.

To achieve the above object, according to another aspect of the present invention, an organic electroluminescent display is characterized in that it includes: a substrate; a first electrode layer formed on the substrate; an organic layer formed on the On the first electrode layer; a second electrode layer is formed on the organic layer and forms a staggered pixel matrix array with the first electrode layer, wherein the substrate, the first electrode layer , the organic layer and the second electrode layer form an organic electroluminescent component; a protective layer covers a part of the second electrode layer, wherein the protective layer has a minimum of One of the constituent elements of electromotive force, whose electromotive force is smaller than the electromotive force of the constituent element having one of the largest electromotive force among the constituent elements of the second electrode layer, is used to protect the organic electroluminescence component from the intrusion of water vapor and oxygen; And an airtight casing for encapsulating the organic electroluminescent component, so as to isolate the organic electroluminescent component from the air and moisture outside.

According to the above idea, the substrate includes a transparent substrate, such as soda lime glass (soda lime), borosilicate glass (borosilicate) or non-alkali glass. The first electrode layer is made of a transparent conductive material, such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc aluminum oxide (AZO) or zinc oxide (ZnO). As the anode of organic electroluminescent components.

The organic layer at least includes an emitting layer. And, the organic layer also includes a hole injection layer and a hole transport layer, which are sandwiched between the first electrode layer and the light emitting layer, and an electron injection layer and an electron transport layer, which are sandwiched between the second electrode layer and the light emitting layer.

The second electrode layer is made of a metal material and is used as a cathode of the organic electroluminescence component. The protective layer is also made of a metal material. In addition, the packaging shell is composed of a metal plate or a glass plate, and the organic electroluminescent component is packaged by combining a packaging medium with the glass plate of the organic electroluminescent component. Generally, the encapsulation medium is composed of an epoxy. After the organic electroluminescent component is hermetically sealed in an airtight package, a dry inert gas such as nitrogen, argon or neon is filled in the inner space of the package to reduce the airtight space inside the package. moisture and oxygen content.

The feature of the present invention is that a protective layer is partially covered on the metal electrode of the organic electroluminescent component, wherein the electromotive force of the component element with the smallest electromotive force among the constituent elements of the protective layer is smaller than that of the metal electrode of the organic electroluminescent component. The electromotive force of the constituent element having the largest electromotive force among the constituent elements of the electrode. Therefore, an effective electrochemical connection is formed between the protective layer and the metal electrodes of the organic electroluminescence component to form a battery structure. The metal electrode of the organic electroluminescence component serves as the cathode of the battery, while the protective layer serves as the anode of the battery. The role of the protective layer is to act as a sacrificial anode, which preferentially interacts with water vapor and oxygen to protect the underlying organic electroluminescence components from oxidation and deliquescence caused by the intrusion of water vapor and oxygen, and can also enhance organic electroluminescence The electron injection efficiency of the component and the luminous efficiency of the organic electroluminescence component. Moreover, the metal oxide formed after the protective layer is oxidized can also be used as a getter to absorb the water vapor captured inside the organic electroluminescent component and the water vapor and oxygen in the airtight space inside the packaging shell of the organic electroluminescent display. , so that the organic electroluminescent component has higher reliability and longer life.

In order to better understand the purpose, features and advantages of the present invention, preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

1 is a cross-sectional view of an organic electroluminescence component according to a first preferred embodiment of the present invention;

FIG. 2 is a schematic structural view showing an organic electroluminescence component according to a first preferred embodiment of the present invention;

3 is a top view of an organic electroluminescence display according to a first preferred embodiment of the present invention;

4 is a cross-sectional view of an organic electroluminescence display according to a first preferred embodiment of the present invention;

5 is a top view of an organic electroluminescence display according to a second preferred embodiment of the present invention;

6 is a top view of an organic electroluminescence display according to a third preferred embodiment of the present invention; and

FIG. 7 is a top view of an organic electroluminescence display according to a fourth preferred embodiment of the present invention.

Please refer to FIG. 1 , which is a cross-sectional view of an organic electroluminescence component according to a first preferred embodiment of the present invention. In Fig. 1, a transparent conductive electrode layer 11, which is composed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc aluminum oxide (AZO) or zinc oxide (ZnO) composed of parallel numbers The electrodes are formed on the substrate 10 by a deposition process such as sputtering, ion plating, or electron beam evaporation. The substrate 10 is also transparent, for example formed of soda lime glass, borosilicate glass or alkali free glass. The transparent electrode layer 11 is used as the anode of the organic electroluminescence component, to provide holes to combine with electrons to emit visible light.

An organic thin film 12 is then deposited on the transparent electrode 11 by evaporation. FIG. 2 shows the structure of the organic electroluminescent device of the present invention, wherein the organic thin film includes at least one emitting layer 123 (emitting layer), in which electrons and holes combine to emit visible light. The organic thin film also includes a hole injection layer (hole injection layer) 121 and a hole transport layer (hole transporting layer) 122, which are sandwiched between the light emitting layer 123 and the transparent electrode layer 11 to provide injection and transport of the emitted light from the transparent electrode layer 11. holes to the light-emitting layer 123, and an electron injection layer (electron injection layer) 125 and an electron transport layer (electron transporting layer) 124, which are sandwiched between the light-emitting layer 123 and the subsequently deposited metal electrode layer 13 to provide injection and transport electrons emitted by the metal electrode layer 13 to the light emitting layer 123 .

After the organic film 12 is formed, a metal electrode layer 13 is deposited on the organic film 12 . The metal electrode layer 13 is composed of metal materials such as aluminum, copper, magnesium, magnesium-silver alloy, aluminum-lithium alloy, aluminum-calcium alloy, etc., and is deposited by evaporation, electron beam evaporation or sputtering. form. The metal electrode layer is composed of several metal electrodes parallel to each other, and the arrangement direction is toward the direction intersecting with the transparent electrodes 11, so that a two-dimensional matrix array is formed on the organic electroluminescence component. A pixel is formed at the intersection of the transparent electrode 11 and the metal electrode 13 . Therefore, the transparent electrodes 11 and the metal electrodes 13 of the organic electroluminescence component form a staggered LED array.

After the metal electrodes 13 are formed, the manufacturing process of the organic electroluminescent device is completed. According to the present invention, in order to protect the organic electroluminescence component from oxidation or deliquescence caused by moisture and oxygen intrusion, a protective layer 14 is covered on a part of the metal electrode wires 13 . The protective layer 14 is made of a metal material, such as calcium, barium, strontium, calcium aluminum, calcium copper, barium aluminum, barium copper, barium silver, etc., deposited by evaporation, electron beam evaporation or sputtering And formed. The protective layer 14 is characterized in that the constituent element having the smallest electromotive force among the constituent elements of the protective layer 14 is smaller than the electromotive force of the constituent element having the largest electromotive force among the constituent elements of the metal electrode 13, because the direct contact between the two With electrical conduction, the protective layer 14 forms an effective galvanic connection with the metal electrode 13 of the organic electroluminescence component, forming a galvanic cell structure. The metal electrode 13 of the organic electroluminescent component is used as the cathode of the storage battery, and the protective layer 14 is used as the sacrificial anode of the storage battery. As shown in FIG. 3 , the protective layer 14 partially covers the pixel area of the metal electrode 13 of the organic electroluminescence component, and forms a galvanic connection (galvanic connection) between the two due to electrical conduction, so as to avoid the organic electroluminescence component. A dark spot defect is formed on the pixel area of the excitation light component and the organic thin film 12 deliquesces. The method and principle of protecting the organic electroluminescence device by the protective layer 14 will be discussed in detail in the following description of this article.

Please refer to FIG. 4 , which is a cross-sectional view of an organic electroluminescence display according to a first preferred embodiment of the present invention. After the protective layer 14 partially covers the metal electrode 13 of the organic electroluminescent component, the organic electroluminescent component is packaged with an airtight packaging case (airtight sealing case) 16, and in the airtight packaging case 16 The inner space is filled with a dry inert gas 15 , such as nitrogen, argon or neon, which is used to separate the organic electroluminescence component from the packaging shell 16 . The packaging shell 16 is combined with the glass substrate by means of a sealing agent 19 to isolate the organic electroluminescence component from the outside air and moisture. The packaging case 16 is mainly composed of a glass plate or a metal plate, and the packaging medium 15 is composed of an adhesive epoxy (epoxy), which is used to make the packaging case 15 and the glass substrate 10 of the organic electroluminescent component Combine airtightly. A conductive thin film 17 is arranged outside the packaging shell 16, on which a driving circuit line 18 is connected to apply an external voltage to drive the organic electroluminescent component, so that the organic electroluminescent component emits visible light.

Although the organic electroluminescent display adopts an airtight packaging case 16 to isolate the organic electroluminescence component from the oxygen and moisture in the outside world, the packaging case 16 cannot be absolutely airtight, so the oxygen and moisture in the outside world will still Gradually diffuse and penetrate into the inner space of the packaging shell and invade the organic electroluminescence component. In addition, the glass substrate 10 will also trap water vapor during the wet process of the organic electroluminescent device. This will cause the organic electroluminescent component to be invaded by external moisture and oxygen as well as the moisture captured inside itself, resulting in non-luminous black spot defects and deliquescence of the organic layer on the pixels of the organic electroluminescent component. As mentioned above, if the metal material of the metal electrode 13 of the organic electroluminescent device is a highly active metal, it is easy to be oxidized and corroded. Therefore, if the upper part of the metal electrode 13 of the organic electroluminescent component is covered with a protective layer 14 made of a metal material, and the constituent elements of the protective layer 14 have the smallest electromotive force, the electromotive force is smaller than that of the metal. The electromotive force of the constituent elements with the largest electromotive force among the constituent elements of the electrode 13 can form an effective electrochemical connection with each other to form a storage battery. For the storage battery formed by the protective layer 14 and the metal electrode 13 of the organic electroluminescent component, the protective layer 14 is used as the sacrificial anode of the storage battery, so when water vapor and oxygen invade the organic electroluminescent component, the water vapor and oxygen are only It will react with the protective layer 14 to cause the conductive material of the protective layer 14 to undergo an oxidation reaction to release electrons and send them to the cathode of the storage battery (ie, the metal electrode 13 of the organic electroluminescence component). Therefore, the electron injection efficiency (electron injection efficiency) of the organic electroluminescent component will be improved, and the oxidation reaction will only occur on the protective layer 14, and the cathode 13 of the organic electroluminescent component will be protected by the protective layer without Oxidation is caused by the intrusion of moisture and oxygen from the outside. The function of the protective layer 14 is to act as a sacrificial anode. When the water vapor and oxygen captured in the outside and the organic electroluminescence component invade into the organic electroluminescent component, the protective layer 14 will react with the water vapor and oxygen. Oxidation to release electrons to protect the metal electrode 13 of the organic electroluminescent component and the organic film 12 below so that it will not be oxidized and deliquescent, prevent the metal electrode 13 of the organic electroluminescent component from being oxidized to produce black spot defects, and It can effectively reduce the concentration of oxygen and water vapor in the airtight space inside the organic electroluminescent display, and prevent the deliquescence of the organic thin film 12 .

Another advantage of the protective layer 14 is that if a metal element with low electromotive force such as calcium or barium is selected as the conductive material of the protective layer 14, the metal oxide produced after the protective layer 14 is oxidized, such as calcium oxide or barium oxide, will It is a porous and discontinuous oxide film rather than a dense oxide film. Therefore, after the metal oxide is formed, the metal of the protective layer 14 still has an exposed space to be further oxidized to protect the metal electrode 13 of the organic electroluminescence component. Therefore, no matter the water vapor captured inside the organic electroluminescent device or the water vapor and oxygen outside the organic electroluminescent device will be absorbed by the metal oxide formed on the protective layer 14 . Therefore, the function of the protective layer 14 can not only be used as a protective film of the organic electroluminescent component to protect the organic electroluminescent component from oxidation and deliquescence, but also the metal oxide formed after being oxidized itself can also be used as Used as a getter.

For the protective effect of the protective layer 14 on the organic electroluminescent component, the most important factor is the galvanic effect between the protective layer 14 and the metal electrode 13 of the organic electroluminescent component. The factors that determine the strength of the electrochemical effect between the protective layer 14 and the metal electrode 13 of the organic electroluminescent device can be discussed in the following three points. One is the area ratio of the metal electrode 13 and the protective layer 14 of the organic electroluminescent device. The larger the ratio of the area of the metal electrode 13 to the area of the protective layer 14 of the organic electroluminescent device, the stronger the reactivity of the protective layer 14 with moisture and oxygen. Therefore, if the area of the protective layer 14 is smaller than the area of the metal electrode 13 of the organic electroluminescent component, the galvanic effect between the protective layer 14 and the metal electrode 13 of the organic electroluminescent component is stronger. Please refer to FIG. 3 again. In FIG. 3 , the protection layer 14 partially covers the pixel light-emitting area of the metal electrode 13 of the organic electroluminescence device. As discussed above, because the constituent element with the smallest electromotive force among the constituent elements of the conductive material forming the protective layer 14, its electromotive force is smaller than the electromotive force of the constituent element with the largest electromotive force among the constituent elements forming the metal electrode 13 of the organic electroluminescence component, A galvanic cell effect is formed due to electrical conduction between them, so water vapor and oxygen only interact with the protective layer 14 to protect the organic electroluminescence component and improve the electron injection efficiency of the organic electroluminescence component. In addition, since the protective layer 14 does not completely cover the metal electrode 13 , but partially covers the display area of the metal electrode 13 of the organic electroluminescent device. Therefore, the electrochemical effect between the protective layer 14 and the metal electrode 13 of the organic electroluminescent device is much better than the electrochemical effect formed when the protective layer 14 completely covers the metal electrode 13 . On the other hand, the function of the protective layer 14 is not only to protect the organic electroluminescence components from the water vapor and oxygen intruding into the organic electroluminescence components, but also to reduce the concentration of water vapor and oxygen in the airtight space of the organic electroluminescence display. Moreover, the electrochemical effect formed with the metal electrode 13 of the organic electroluminescence component can also improve the overall luminous efficiency. 5 shows a top view of an organic electroluminescent display according to a second preferred embodiment of the present invention, in which the protective layer 14 covers the non-display area on the metal wire 13 near the wire 20 connected to the outside of the package. Therefore, the area ratio of the metal electrode 13 to the protective layer 14 will be higher, and the electrochemical effect formed between the two due to electrical conduction will be stronger, so that the protective layer can more quickly remove the moisture and moisture in the airtight space. oxygen. On the other hand, the metal oxide formed after the protective layer 14 is oxidized usually has a molar volume different from that of the metal conductor forming the protective layer 14, and the stress generated is the molar volume difference. It does not directly act on the pixels of the organic electroluminescent component, and can greatly reduce the damage caused to the multilayer structure in the pixel structure of the organic electroluminescent component. FIG. 6 shows a top view of an organic electroluminescence display according to a third preferred embodiment of the present invention, in which the protection layer 14 only covers the left side of the non-display area on the metal electrode 13 . FIG. 7 shows a top view of an organic electroluminescence display according to a fourth preferred embodiment of the present invention, in which the protection layer 14 only covers the right side of the non-display area on the metal electrode 13 . Compared with Fig. 5, the area ratio of the metal electrode 13 to the protective layer 14 in Fig. 6 and Fig. 7 is greater than the area ratio of the metal electrode 13 to the protective layer 14 in Fig. 5, so in Fig. 6 and Fig. 7 the protective layer 14 is to the metal The electrochemical effect formed by the wire 13 will be stronger, and the protective layer 14 can interact with the water vapor and oxygen more quickly to remove the water vapor and oxygen in the airtight space.

The second factor that determines the strength of the electrochemical effect formed between the protective layer 14 and the metal electrode 13 of the organic electroluminescent component due to electrical conduction depends on the contact between the protective layer 14 and the metal electrode 13 of the organic electroluminescent component. Electrochemical potential difference (ie electromotive force difference). Table 1 lists the standard electromotive potentials of metal elements, which are represented by reduction potentials (Table 1 is from "Handbook of Chemistry and Physics", 71st edition (71 ^st ed.), CRC Press ( CRC Press), 1991 and W. Latimer (W.Latimer), "The Oxidation Potentials of the Elements and Their Values in Aqueous Solution (The Oxidation Potentials of the Elements and Their Values in Aqueous Solution)", Prentice-Ho Prentice-Hall, Englewood Cliffs, NJ, 1952). For example, if aluminum (its electromotive force is -1.662V), zinc (its electromotive force is -0.7628V), chromium (its electromotive force is -0.744V), indium (its electromotive force is -0.343V), tin (its electromotive -0.136V), copper (its electromotive force is 0.337V), silver (its electromotive force is 0.7991V) as a constituent element of the metal electrode 13 of the organic electroluminescence component, then lithium (its electromotive force is -3.045V ), calcium (its electromotive force is -2.866V), strontium (its electromotive force is -2.888V), barium (its electromotive force is -2.906V), magnesium (its electromotive force is -2.363V), scandium (its electromotive force is -2.077V ) and other low electromotive force metals as a constituent element of the protective layer 14 . If the electrochemical potential difference (that is, the electromotive force difference) between the protective layer 14 and the metal electrode 13 of the organic electroluminescent component is larger, the electrochemical effect formed between the protective layer 14 and the metal electrode 13 of the organic electroluminescent component will be larger. The stronger it is, the higher the reaction force of the protective layer 14 is to moisture and oxygen.

The third determining factor is the distance between the protective layer 14 and the metal electrode 13 of the organic electroluminescence component. If the distance between the two is shorter, the formed galvanic connection is stronger, and the reactivity of the protective layer 14 with moisture and oxygen is also stronger. According to the present invention, the protective layer 14 is directly covered on the metal electrode 13 of the organic electroluminescence component, so the distance between the two is very close, and the formed electrochemical connection will be the strongest. Therefore, the electrochemical effect formed by the protective layer 14 and the metal electrode 13 of the organic electroluminescent component and the protective effect of the protective layer 14 on the organic electroluminescent component are also optimal.

Claims (18)

1. A method for manufacturing an organic electroluminescence display, characterized in that the method may further comprise the steps: forming a first electrode layer on a substrate; forming an organic layer over the first electrode layer; A second electrode layer is formed above the organic layer, and the second electrode layer and the first electrode layer form a staggered pixel matrix array, wherein the substrate, the first electrode layer, and the organic layer forming an organic electroluminescence component with the second electrode layer; Covering a protective layer over a part of the second electrode layer, wherein a constituent element having the smallest electromotive force among the constituent elements of the protective layer is smaller than a constituent element having the largest electromotive force among the constituent elements of the second electrode layer An electromotive force of a constituent element of , used to protect the organic electroluminescent device from the intrusion of moisture and oxygen; and The organic electroluminescent component is encapsulated with an airtight shell, so as to isolate the organic electroluminescent component from the outside air and moisture. 2 . The method according to claim 1 , wherein the substrate comprises a transparent substrate, and the transparent substrate is composed of one of a soda lime glass, a borosilicate glass and an alkali-free glass. 3 . 3. The method according to claim 1, wherein the first electrode layer is made of a transparent conductive material, and the transparent conductive material is made of an indium tin oxide, an indium zinc oxide, an Composed of one of zinc aluminum oxide and zinc monoxide. 4. The method of claim 1, wherein the first electrode layer is formed by one of a sputtering method, an ion plating method and an electron beam evaporation method. 5. The method of claim 1, wherein the organic layer is formed by an evaporation method. 6. The method of claim 1, wherein the second electrode layer is composed of a metal material. 7. The method of claim 1, wherein the second electrode layer is formed by one of an evaporation method, an electron beam evaporation method and a sputtering method. 8. The method of claim 1, wherein the protective layer is made of a metal material. 9. The method of claim 1, wherein the protective layer is formed by one of an evaporation method, an electron beam evaporation method and a sputtering method. 10. The method of claim 1, wherein the airtight package is formed of one of a metal plate and a glass plate. 11. The method according to claim 1, wherein the airtight packaging casing is combined with the substrate by means of a packaging medium to package the organic electroluminescence component, and the packaging medium includes a epoxy. 12. The method of claim 1, further comprising the step of filling a dry inert gas inside the airtight enclosure. 13. A method for protecting an organic electroluminescence display, characterized in that the method comprises the following steps: An organic electroluminescent component is provided, wherein the organic electroluminescent component includes a substrate, a first electrode layer is formed on the substrate, an organic layer is formed on the first electrode layer, and a The second electrode layer is formed on the organic layer and forms a staggered pixel matrix array with the first electrode layer; A protective layer is covered on a part of the second electrode layer, wherein, among the constituent elements of the protective layer, an electromotive force of a constituent element having the smallest electromotive force is smaller than that of the constituent elements of the second electrode layer. the electromotive force of the constituent elements, one of the largest electromotive forces, to protect the organic electroluminescent device from the intrusion of moisture and oxygen; and The organic electroluminescent component is packaged with an airtight packaging shell, so as to isolate the organic electroluminescent component from the air and moisture outside. 14. An organic electroluminescent display, characterized in that it comprises: a substrate; a first electrode layer formed on the substrate; an organic layer formed on the first electrode layer; A second electrode layer is formed on the organic layer and forms a staggered pixel matrix array with the first electrode layer, wherein the substrate, the first electrode layer, the organic layer and the The second electrode layer forms an organic electroluminescence component; A protective layer covering a part of the second electrode layer, wherein, among the constituent elements of the protective layer, one of the constituent elements having the smallest electromotive force is smaller than that of the constituent elements of the second electrode layer The electromotive force of the constituent element having one of the largest electromotive forces in the organic electroluminescence device is used to protect the intrusion of moisture and oxygen; and An airtight casing is used for encapsulating the organic electroluminescent component, so as to isolate the organic electroluminescent component from outside air and moisture. 15. The organic electroluminescence display according to claim 14, wherein the organic layer comprises at least one light emitting layer. 16. The organic electroluminescence display according to claim 15, wherein the organic layer further comprises a hole injection layer and a hole transport layer, which are sandwiched between the first electrode layer and the light emitting layer between. 17. The organic electroluminescent display according to claim 15, wherein the organic layer further comprises an electron injection layer and an electron transport layer, which are sandwiched between the second electrode layer and the light emitting layer between. 18. The organic electroluminescence display as claimed in claim 14, wherein the inner space of the airtight packaging case is filled with a dry inert gas to lower the inner space of the airtight packaging case. The concentration of water vapor and oxygen in space.

Images