KR20060068678A - Method for fabricating organic electro luminescence display device - Google Patents

Abstract

The present invention relates to a method of manufacturing an organic electroluminescent display device capable of improving image quality.

A method of manufacturing an organic light emitting display device according to the present invention includes the steps of forming an anode electrode on a substrate; Partially exposing the anode electrode to form an insulating film defining a light emitting region; Forming an organic light emitting layer on the light emitting region; Forming a cathode electrode intersecting the anode electrode with the organic light emitting layer interposed therebetween, wherein at least one of forming the organic light emitting layer and forming the cathode electrode is baking the organic light emitting layer. Characterized in that it comprises a step.

Description

Manufacturing method of organic electroluminescent display device {Method For Fabricating Organic Electro Luminescence Display Device}             

1 is a view schematically showing a conventional organic electroluminescent display device.

FIG. 2 is a cross-sectional view showing one EL cell, taken along line II ′ of FIG. 1.

3 is a diagram for explaining a light emission principle of an organic light emitting display device.

4A to 4F illustrate a method of manufacturing an organic light emitting display device according to a first embodiment of the present invention.

5 is a view illustrating a method of manufacturing an organic light emitting display device according to a second embodiment of the present invention.

    <Explanation of symbols for the main parts of the drawings>

2,102 substrate 4,104 anode electrode

8,108: partition 10,110: organic light emitting layer

12,112 cathode electrode

The present invention relates to an organic electroluminescent display device, and more particularly, to a method for manufacturing an organic electroluminescent display device capable of improving image quality.

Recently, various flat panel displays have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes. Such a flat panel display includes a liquid crystal display, a field emission display, a plasma display panel, and an electroluminescence display device. And the like). In particular, the EL display device is basically formed by attaching electrodes to both sides of an organic light emitting layer including a hole transporting layer, a light emitting layer, and an electron transporting layer.

Such EL display elements are largely divided into inorganic EL display elements and organic EL display elements depending on the materials used. Among them, the organic EL display device can be driven at a lower voltage than the inorganic EL display device because when the charge is injected into the organic EL layer formed between the hole injection electrode and the electron injection electrode, electrons and holes are paired and extinguished to emit light. Has the advantage. In addition, the organic EL display device can be formed on a flexible transparent substrate, such as plastic, and can be driven at a voltage lower than 10V compared to a PDP or an inorganic EL display device, and the power consumption is relatively low. Small, excellent color

1 is a cross-sectional view schematically showing a conventional organic EL display device, and FIG. 2 is a view showing one organic electroluminescent cell (hereinafter referred to as an "EL cell") cut away from line I-I 'shown in FIG. 3 is a cross-sectional view illustrating the light emission principle of the organic EL display device.

1 to 3, an organic EL display device includes a first electrode (or anode electrode) 4 and a second electrode (or electrode) formed to cross each other with an organic light emitting layer 10 therebetween on a substrate 2. An organic EL array 15 including a cathode electrode 12, etc., and a cap 28 for packaging the organic EL array 15 are provided.

A plurality of anode electrodes 4 of the organic EL array 15 are spaced apart at predetermined intervals on the substrate 2. On the substrate 2 on which the anode electrode 4 is formed, an insulating film 6 having an opening for each EL cell EL region is formed. On the insulating film 6, a partition 8 for separating the organic light emitting layer 10 and the cathode electrode 12 to be formed thereon is positioned. The partition wall 8 is formed in a direction crossing the anode electrode 4 and has a reverse taper structure in which the upper end portion has a wider width than the lower end portion. On the insulating film 6 on which the partition 8 is formed, the organic light emitting layer 10 and the cathode electrode 12 made of an organic compound are sequentially deposited on the entire surface. As shown in FIG. 2, the organic light emitting layer 10 includes an electron injection layer 10a, an electron transport layer 10b, a light emitting layer 10c, a hole transport layer 10d, and a hole injection layer 10e.

The organic EL array 15 has a property that is easily degraded by moisture and oxygen. To solve this problem, an organic EL array 15 is formed by encapsulation process in which the substrate 2 and the cap 28 on which the organic EL array 15 is formed are bonded through a sealant 25 such as an epoxy resin. ) Is protected from oxygen and moisture.

The cap 28 is provided with a getter 22 positioned on a surface facing the organic EL array 15 to absorb moisture and oxygen, and a semipermeable membrane 24 for fixing the getter 22. do. Here, the getter 22 may be formed of inorganic oxide, that is, calcium oxide (Cao), barium oxide (BaO), or the like, which reacts with water to form hydroxyl groups (OH). Teflon, polyester, paper or the like is used to lift.

In the organic EL display device, as shown in FIG. 3, when a voltage is applied between the anode electrode 4 and the cathode electrode 12, electrons generated from the cathode electrode 12 are transferred to the electron injection layer 10a and the electron. It moves toward the light emitting layer 10c through the transport layer 10b. In addition, holes generated from the anode electrode 4 move toward the light emitting layer 10c through the hole injection layer 10e and the hole transport layer 10d. Accordingly, in the light emitting layer 10c, excitons are formed by recombination of electrons and electrons supplied from the electron transport layer 10b and the hole transport layer 10d, and the excitons are excited to the ground state and emit light of constant energy. The image is displayed by being discharged to the outside through the anode electrode 4.

On the other hand, even if the sealing process for protecting the EL cell of the organic EL display element from moisture and oxygen is performed, the moisture and oxygen in the element are not completely removed. In addition, when the device is driven, impurities such as a very small amount of oxygen in the device and a very small amount of solvent remaining in forming each array may be generated. At this time, the moisture, oxygen, impurity gas and the like penetrates between the cathode electrode 12 formed of aluminum or the like and the electron injection layer 10a of the organic light emitting layer 10 formed of an organic material. As a result, when the image is implemented, a problem occurs that the image quality is deteriorated, such as a dark spot phenomenon in which the area where the moisture, oxygen, and impurity gas is concentrated is darkened.

It is understood that organic matter is formed by a deposition process, so that the cohesive force between organic particles is weak, so that a plurality of moisture and the like can easily penetrate one region. Therefore, a method for preventing the penetration of moisture and the like is desired.

Accordingly, an object of the present invention is to provide an organic electroluminescent display device capable of improving image quality.

In order to achieve the above object, a method of manufacturing an organic electroluminescent display device according to the present invention comprises the steps of forming an anode electrode on a substrate; Partially exposing the anode electrode to form an insulating film defining a light emitting region; Forming an organic light emitting layer on the light emitting region; Forming a cathode electrode intersecting the anode electrode with the organic light emitting layer interposed therebetween, wherein at least one of forming the organic light emitting layer and forming the cathode electrode is baking the organic light emitting layer. Characterized in that it comprises a step.

The forming of the organic light emitting layer may include forming a hole injection layer on the anode; Forming a hole transport layer on the hole injection layer; Forming a light emitting layer on the hole transport layer; Forming an electron transport layer on the light emitting layer; And forming an electron injection layer on the electron transport layer, wherein the baking is performed after the electron injection layer is formed.

The baking is characterized in that carried out at a temperature of 50 ℃ ~ 150 ℃.

And forming a partition wall on the insulating layer to intersect the anode electrode.

Other objects and features of the present invention in addition to the above object will be apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 4A to 5.

4A to 4F are views for explaining a method of manufacturing an organic light emitting display device according to a first embodiment of the present invention.

First, a transparent conductive material is deposited on a substrate 102 formed using soda lime or hardened glass, and then patterned by a photolithography process and an etching process to thereby form a first electrode (or as shown in FIG. 4A). Anode electrode 104 is formed. In this case, indium tin oxide or SnO 2 may be used as the transparent conductive material.

A photosensitive insulating material, for example, polyimide or the like is coated on the substrate 102 on which the anode electrode 104 is formed by spin-coating, and then patterned by a photolithography process. As shown in FIG. 1, an insulating film 106 is formed to expose the light emitting region P1.

The photosensitive organic material is deposited on the substrate 102 on which the insulating film 106 is formed, and then patterned by a photolithography process to form a partition 108 as illustrated in FIG. 4C.

As shown in FIG. 4C, the organic light emitting layer 110 is formed on the substrate 102 on which the partition 108 is formed by thermal deposition, vacuum deposition, or the like using a common mark and a shadow mask (not shown). Is formed. Here, the organic light emitting layer 110 includes a hole injection layer 110e, a hole transport layer 110d, a light emitting layer 110c, an electron transport layer 110b and an electron injection layer 110a.

Each of the thin films in the organic light emitting layer 110 is formed by the following method.

That is, the hole injection layer 110e and the hole transport layer 110d are sequentially formed by using a method such as vacuum deposition or thermal deposition using a common mask that exposes the organic EL array on the substrate 102 on which the partition 108 is formed. Is deposited.

Thereafter, the red (R), green (G), and blue (B) light emitting layers 110c are formed by using a method such as vacuum deposition or thermal deposition using a shadow mark.

Subsequently, the electron transport layer 110b and the electron injection layer 110a are formed by using the common mask used when the hole injection layer 110e and the hole transport layer 110d are formed.

Such a plurality of thin films in the organic light emitting layer 110 are formed of an organic material.

Thereafter, a baking process is performed as shown in FIG. 4E to increase cohesion or binding force between organic particles in the thin films. This baking process increases the cohesion or bonding force between the particles in the organic material and serves to cure the thin film. Accordingly, the particles of the organic materials are firmly bonded to each other, thereby preventing oxygen, moisture, and the like from penetrating into the organic material and the surface. In addition, since the organic materials are hardened, the adhesion to the cathode electrode 112 to be formed thereafter is improved. Accordingly, penetration of oxygen, moisture, or the like is prevented between the cathode electrode 112 and the electron injection layer 110a of the organic light emitting layer, so that dark spots do not occur. As a result, the image quality at the time of image implementation of the element is improved.

Thereafter, a metal material is deposited on the substrate 102 on which the organic light emitting layer 110 is formed, thereby forming the cathode electrode 112 as shown in FIG. 4F.

5 is a view for explaining a method of manufacturing an organic light emitting display device according to a second embodiment of the present invention.

The method of manufacturing the organic electroluminescent display device according to the second embodiment of the present invention is the same as that of the first embodiment of the present invention shown in FIGS. 4A to 4F except that the baking process is performed when the cathode electrode 112 is formed. Since the organic electroluminescent display device according to the same as the manufacturing method of the same reference numerals will be omitted.

The organic light emitting layer 110 is formed in the same manner as in FIGS. 4A to 4D. Thereafter, as shown in FIG. 5, the cathode electrode 112 is formed and a baking process is performed. Accordingly, the cohesive force or the bonding force between the organic particles in the plurality of organic thin films of the organic light emitting layer is increased and the plurality of organic thin films are cured. Accordingly, penetration of oxygen, moisture, or the like is prevented between the cathode electrode 112 and the electron injection layer 110a of the organic light emitting layer so that dark spots do not occur. Here, baking temperature is about 50-150 degreeC, Preferably it is about 60-100 degreeC.

As described above, in the method of manufacturing the organic EL display device according to the present invention, after the organic light emitting layer is formed or the cathode is formed, the organic light emitting layer is baked. Accordingly, the particles of the organic materials are firmly bonded to each other, thereby preventing oxygen, moisture, and the like from penetrating into the organic material and the surface. In addition, since the organic materials are hardened, adhesion to the cathode electrode to be formed thereafter is improved. Accordingly, penetration of oxygen, moisture, or the like is prevented between the cathode electrode and the electron injection layer of the organic light emitting layer, so that dark spots do not occur. As a result, the image quality at the time of image implementation of the element is improved.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (4)

Forming an anode on the substrate; Partially exposing the anode electrode to form an insulating film defining a light emitting region; Forming an organic light emitting layer on the light emitting region; Forming a cathode electrode intersecting the anode electrode with the organic light emitting layer interposed therebetween, At least one of the step of forming the organic light emitting layer and the step of forming the cathode electrode Method of manufacturing an organic electroluminescent display device comprising the step of baking the organic light emitting layer. The method of claim 1, Forming the organic light emitting layer is Forming a hole injection layer on the anode; Forming a hole transport layer on the hole injection layer; Forming a light emitting layer on the hole transport layer; Forming an electron transport layer on the light emitting layer; Forming an electron injection layer on the electron transport layer; The baking is a method of manufacturing an organic light emitting display device, characterized in that is carried out after forming the electron injection layer. The method of claim 1, The baking is a method of manufacturing an organic light emitting display device, characterized in that carried out at a temperature of 50 ℃ ~ 150 ℃. The method of claim 1, And forming a partition wall on the insulating layer to intersect the anode electrode.

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