KR100621861B1 - Organic Electro Luminescence Device and Method Fabricating Thereof - Google Patents

Abstract

The present invention relates to an organic electroluminescent device and a method of manufacturing the organic electroluminescent device that can simplify the device structure and improve the lifespan by manufacturing the absorbent in a thin film form.

An organic electroluminescent device according to the present invention includes a first electrode formed to have a stripe shape at a predetermined interval on a transparent substrate, an insulating film formed at a predetermined position on the first electrode to electrically insulate the first electrode, A barrier rib formed on the insulating layer to separate the first electrode, a second electrode of a metal material applied to the entire surface of the transparent substrate, and a first electrode and the second electrode to form light by an externally applied voltage. An organic light emitting layer that emits, a seal cover plate formed in a plane to seal the EL layer, and a moisture absorbing film formed on a seal cover plate to absorb moisture components generated by releasing gas from the insulating film or the partition wall. And a space for bonding the seal cover plate and the transparent substrate and injecting an inert gas to prevent deterioration. It characterized in that it comprises a seed iljae formed over a predetermined size to ensure.

According to the present invention, by forming a thin film-type absorbent evenly, it is easy to release the heat generated when driving the panel of the electroluminescent device to prevent excessive deterioration of the device to improve the reliability as well as simplify the process and manufacturing cost.

Description

Organic electroluminescent device and method of manufacturing the same {Organic Electro Luminescence Device and Method Fabricating Thereof}             

1 is a plan view showing an upper substrate of a general ELD.

FIG. 2 is a cross-sectional view showing a surface cut along the line “A-A '” in FIG. 1; FIG.

3A to 3E are cross-sectional views illustrating a method of manufacturing an upper substrate of the ELD shown in FIG. 2.

4 is a view showing that a moisture absorbent according to the prior art is formed.

5 is a view showing that a different method of hygroscopic agent is formed according to the prior art.

6 is a view showing forming a moisture absorbent in the form of a thin film on the lower substrate of the organic electroluminescent device according to the present invention.

7 is a plan view and a cross-sectional view showing that a moisture absorbing film 42 is deposited on the seal cover plate 40 according to the process shown in FIG. 6.

8 is a schematic view of an organic electroluminescent device according to a first embodiment arranged to bond an upper substrate and a lower substrate formed by FIGS. 6 and 7.

9 is a view schematically showing an organic electroluminescent device according to a second embodiment of the present invention.

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

2,32 transparent substrate 4,34 transparent electrode

6,36 insulating film 8,38 partition wall

10 EL layer 12 cathode electrode

22,22-1: Seal cover plate 14,24: Hygroscopic

18,44 spacer 20,46 seal material

40: seal cover plate 48: metal mask

50: moisture absorbing material 42: moisture absorbing film

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescent device, and more particularly, to an organic electroluminescent device and a method of manufacturing the same, which can simplify the device structure and improve the lifespan by manufacturing the absorbent in a thin film form.

Recently, various flat panel displays have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes. Such flat panel displays include liquid crystal displays (hereinafter referred to as "LCD"), field emission displays (hereinafter referred to as "FED"), plasma display panels (hereinafter referred to as "PDP"). And electroluminescent devices (hereinafter referred to as "ELD"). In particular, ELD is basically formed by attaching electrodes to both sides of an EL layer including a hole transport layer, a light emitting layer, and an electron transport layer, and is attracting attention as a next-generation flat panel display because of its wide viewing angle, high opening ratio, and high color.

Such ELDs are largely divided into inorganic ELDs and organic ELDs depending on the materials used. Among them, the organic ELD has the advantage of being able to be driven at a lower voltage than the inorganic ELD 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 up and extinguished to emit light. . In addition, organic ELDs can form devices on flexible flexible substrates, such as plastics, and can be driven at lower voltages of 10V or less than PDPs or inorganic ELDs, and have a relatively low power consumption. This is excellent.

The ELD is divided into a passive ELD and an active ELD according to a driving method.

1 is a plan view showing an upper substrate of a general ELD. FIG. 2 is a cross-sectional view showing a plane cut by "A-A '" in FIG. 1.

Referring to FIGS. 1 and 2, the upper substrate of the ELD includes a transparent electrode 4 arranged in a row in a band on the transparent substrate 2, and a protective film formed on the front surface including the transparent electrode 4. Not shown), an organic electroluminescent layer (hereinafter referred to as "EL layer", 10) formed by laminating a hole transporting layer, a light emitting layer and an electron transporting layer on the passivation layer, and crossing the transparent electrode on the EL layer in a band shape. The formed cathode electrode 12 is provided. In addition, the partition wall 8 is formed in the same band between the cathode electrode 12 for separating the cathode electrode 12.

In the panel formed as described above, when an electric current flows between the cathode transparent electrode 4 and the cathode electrode 12 on the transparent substrate 2, the EL layer 10 deposited as a thin film between the two electrodes emits light to operate. do.

3A to 3E are cross-sectional views illustrating a method of manufacturing an upper substrate of the ELD shown in FIG. 2.

Referring to FIG. 3A, a transparent electrode 4 for a cathode is patterned on a transparent substrate 2 in a stripe pattern by a photolithography method (Phtolithography) including a wet method.

Referring to FIG. 3B, an insulating film 6 is formed on the transparent substrate 2 by photolithography.

Referring to FIG. 3C, the partition wall 8 is formed on the transparent substrate 2 by a photolithography method. At this time, the partition wall is formed at regular intervals to intersect the transparent electrode (4).

Referring to FIG. 3D, the EL layer 10 is deposited on the entire surface on the transparent substrate 2. In this case, the EL layer 10 is formed by stacking a hole transport layer, an emission layer, and an electron transport layer.

Referring to FIG. 3E, the cathode electrode 12 is entirely deposited on the EL layer 10 deposited on the transparent substrate 2. At this time, the cathode electrode 12 is collectively deposited on the entire surface of the light emitting effective surface without any particular shape, but previously separated from the neighboring cathode electrode 12 by the partition wall 8 in a band shape.

The emission principle of the organic ELD emits light by recombination of holes and electrons injected through the electrode. That is, the carriers (electrons and holes) are injected from the electrodes into the organic film, the carriers move to the opposite electrodes of the injected carriers, the excitons are generated by recombination of the carriers, the excitons are moved (diffusion), and the light is emitted from the excitons. . Thus, light of any particular wavelength determined by the material is irradiated, and the material is excited and emits light.

In addition, the ELD includes seal cover plates 22 and 22-1 bonded to face the upper substrate formed by the manufacturing process as shown in FIGS. 4 and 5. In this case, the seal cover plates 22 and 22-1 and the transparent substrate 2 are sealed materials such as epoxy resins according to a general encapsulation method in a sealed place with an inert gas such as nitrogen or argon. ) Is sandwiched between them. In addition, the spacer 18 is formed to be inserted when the seal cover plates 22 and 22-1 and the upper substrate 2 are bonded to each other. The spacer 18 serves to achieve a predetermined spacing upon bonding.

However, since the cathode electrode made of the EL layer 6 and the metal of the ELD reacts easily with moisture or oxygen in the air, deterioration occurs in the device.

Therefore, moisture is removed using the moisture absorbents 14 and 24, and the seal cover plates 22 and 22-1 and the transparent substrate 2 are joined by a seal material under an inert gas. At this time, nitrogen (N ₂ ), which is an inert gas, is injected into the space formed by bonding the seal cover plates 22 and 22-1 and the transparent substrate 2.

Here, the seal cover plates 22 and 22-1 are formed of glass, plastic, canister, or the like as a material. As the moisture absorbents 14 and 24, fine powders such as barium oxide (BaO), calcium carbonate (CaCO 3), zeolite, silica gel and alumina are used. However, it is important that the moisture absorbents 14 and 24 are formed evenly and evenly.

There are two types of absorbents 14 and 24. One is to form a groove in the seal cover plate 22 as shown in FIG. 4, and the absorbent 14 is contained in the groove of the seal cover plate 22. It is used by attaching a supporting film such as paper or Teflon.

The other is a method of packaging the powder absorbent 24 in the form of a sheet (Sheet) as shown in Figure 5 and then attach it to the seal cover plate (22-1).

In the prior art, CaO + H ₂ O = Ca (OH) ₂ or BaO + H ₂ O = Ba (OH) ₂ to adsorb moisture generated in the organic electroluminescent device. The fine moisture component generated in the organic partition 8 and the insulating film 6 in the ELD is made to penetrate and adsorb through the porous support membrane supporting the moisture absorbents 14 and 24. At this time, the moisture absorption rate can be increased by making the powder state of the moisture absorbents 14 and 24 coarsened and increasing the surface area which moisture can contact.

However, the powder-based moisture absorbents 14 and 24 in the prior art use materials in the form of powders themselves, which is not only inconvenient to handle during the process but also affects pollution problems such as powder blowing inside the equipment or worker safety. There is this. In the case of Figure 4, the thickness of the moisture absorbent (14) can only be adjusted to the depth of the grooves in the seal cover plate 12, so when using the seal cover plate 12, the mold is added to increase the cost and the thickness of the product will also be thick There is no choice but to. As in the case of FIG. 5, the moisture absorbent in the form of a sheet is required to package the powder as a raw material, and thus, the cost incurred in this process is high, and considering the thickness of the package, there is a limit in reducing the thickness while maintaining performance. In addition, the location of the absorbent is also limited to the center portion of the panel has a limit to ensure the lifetime reliability of the device far from the absorbent. In addition, since moisture reaches the moisture absorbent through the porous support membrane, there is a problem in that the moisture absorption rate is limited to the material or the pore density of the membrane.

Accordingly, an object of the present invention is to form a glass seal cover plate by forming a moisture absorbent in a thin film form to simplify the structure and manufacturing process of the organic electroluminescent device and to improve the lifetime reliability, and an organic electroluminescent device and its manufacturing method It is about.

In order to achieve the above object, the organic electroluminescent device according to the present invention comprises a first electrode formed to have a stripe shape at a predetermined interval on a transparent substrate, and formed at a predetermined position on the first electrode and between the first electrode. An insulating film for electrical insulation, a partition wall formed on the insulating film so as to separate the first electrode, a second electrode of a metallic material applied to the entire surface of the transparent substrate, and between the first electrode and the second electrode An organic light emitting layer formed on the substrate to emit light by an externally applied voltage, a seal cover plate formed on a plane to seal the EL layer, and formed on the seal cover plate to emit gas from the insulating film or the partition wall. The moisture absorbing film in the form of a thin film absorbing the generated moisture component, the seal cover plate and the transparent substrate, A characterized in that it comprises a seed iljae formed over a predetermined size to secure a space for to inject an inert gas for preventing.

In an embodiment of the present invention, a spacer may be further included to prevent the partition wall from being damaged when the seal member is bonded between the seal cover plate and the transparent substrate.

The moisture absorption film of the present invention is characterized in that it is composed of any one of barium oxide (BaO), calcium carbonate (CaCO ₃ ), zeolite, zeolite, silica gel, alumina.

According to an aspect of the present invention, there is provided a method of manufacturing an organic light emitting display device, the method comprising: forming an upper substrate to display an image on a panel by applying an electrical signal, and forming a seal cover plate such as glass to correspond to the upper substrate; Depositing a moisture absorbing film in the form of a thin film to absorb moisture from the upper substrate through the metal mask on the seal cover plate, and bonding the upper cover with the seal cover plate on which the moisture absorbing film is deposited. It features.

The step of depositing a moisture absorbing film in the present invention includes the step of depositing a moisture absorbing material having a moisture absorbing property only in a portion constituting the front or panel portion of the seal cover plate by a sputtering or PECVD method.

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. 6 to 9.

The organic ELD is composed of an upper substrate on which organic material is deposited on the patterned ITO glass, and a lower substrate formed of glass to be bonded to the upper substrate.

Herein, the manufacturing process of the upper substrate is the same as described with reference to FIGS. 1 and 2, and the manufacturing process thereof will be omitted.

The upper substrate of the ELD is a transparent electrode 34 arranged in a row in a strip shape on the transparent substrate 32, an insulating film 36 formed on the entire surface including the transparent electrode 34, and on the insulating film 36 An EL layer formed by laminating a hole transporting layer, a light emitting layer, and an electron transporting layer, and a cathode electrode formed in a band shape on the EL layer to intersect the transparent electrode. In addition, a partition 38 is formed in the same band between the cathode electrode for separating the cathode electrode.

When a current flows between the cathode transparent electrode 34 and the cathode metal electrode on the transparent substrate 32 in the panel formed as described above, the EL layer deposited as a thin film between the two electrodes operates to emit light.

Next, the lower substrate formed to correspond to the upper substrate is formed as shown in FIG. 6.

Referring to FIG. 6, in the organic electroluminescent device according to the present invention, the lower substrate is a metal mask which selectively deposits an absorbent only on a portion of the seal cover plate 40 formed flat with ITO glass and a panel on the upper substrate. 48 and a hygroscopic material 50 for depositing a hygroscopic agent on the seal cover plate 40.

Looking at the manufacturing process, the sputtering process or PECVD (Plasma) of the material 50 having a hygroscopic property through the metal mask 48 that is perforated only on the part forming the panel on the flat seal cover plater 40 The moisture absorption film 42 is formed using a method such as Enhanced Chemical Vapor Deposition.

In case of using PECVD (Plasma Enhanced Chemical Vapor Deposition) method, the gas required for deposition is injected into the chamber forming the vacuum chamber, and when the desired pressure and substrate temperature are set, the injected gas is decomposed into a plasma state using a high frequency power source. The hygroscopic material is deposited on the substrate.

Metal oxides such as barium oxide (BaO) and calcium carbonate (CaCO ₃ ) are usually deposited by sputtering, in which gas ions having high energy in the plasma formed by high frequency and direct current power are absorbed from the surface of the hygroscopic material 50. On the flat seal cover plate 40 to collide and pass through the metal mask, the moisture absorbing material particles are popped out to deposit the moisture absorbing film 42.

FIG. 7 is a plan view and a cross-sectional view showing that a moisture absorption film 42 is deposited on the seal cover plate 40 according to the process shown in FIG. 6.

8 is a schematic view of an organic electroluminescent device according to a first embodiment arranged to bond an upper substrate and a lower substrate formed by FIGS. 6 and 7.

Referring to FIG. 8, the upper substrate includes a transparent electrode 34 arranged in a row on a transparent substrate 32, an insulating film 36 formed on the entire surface including the transparent electrode 34, and the insulating film ( 36) an EL layer formed by laminating a hole transporting layer, a light emitting layer and an electron transporting layer on the same layer, a cathode electrode intersecting the transparent electrode on the EL layer and formed in a band shape, and the same band between the cathode electrode for separating the cathode electrode; A plurality of panel portions formed of partition walls 38 formed in a shape are formed, and a moisture absorbing film 42 having a thin film form is formed on the seal cover plate 40 so as to correspond to the panel portions.

The upper and lower substrates thus formed are spaced apart by spacers and bonded together with a sealing material such as an epoxy resin interposed therebetween according to an encapsulation method. Since the height of the barrier rib is usually 4 to 5 μm, the lower substrate is used to prevent damage to the barrier rib when the upper substrate is bonded, and the size of the spacer is at least 20 μm.

9 is a view schematically showing an organic electroluminescent device according to a second embodiment of the present invention.

Referring to FIG. 9, instead of selectively depositing the moisture absorbing film 42 corresponding to the panel portion through the seal cover plate metal mask, the absorbent may be evenly distributed over the entire surface to prevent deterioration.

At this time, the seal cover plate 40 and the transparent substrate 32 to which the moisture absorption film 42 is applied are sandwiched by a seal member 46 such as an epoxy resin, which is an ultraviolet curable resin, according to an encapsulation method. Are cemented.

Here, the seal cover plate 40 is formed of glass, plastic, canister, or the like as a material. As the moisture absorbent 38, barium oxide (BaO), calcium carbonate (CaCO ₃ ), zeolite, silica gel, alumina, or the like is used.

This causes light emission by applying a current to the EL layer deposited between the transparent electrode and the cathode electrode. After the upper plate and the lower plate are joined, the moisture component generated by releasing gas from the insulating film or the partition wall of the upper plate is absorbed by the thin film getter of the lower plate, thereby improving device life reliability.

As described above, the organic electroluminescent device and its manufacturing method evenly form a thin film-type absorbent on the entire surface of the electroluminescent device to easily release heat generated when driving the panel of the electroluminescent device to prevent excessive deterioration of the device. In addition to improving reliability, the process and manufacturing costs can be simplified.

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 (12)

A first electrode formed on the transparent substrate to have a stripe shape at a predetermined interval; An insulating film formed at a predetermined position on the first electrode for electrical insulation between the first electrodes; Barrier ribs formed on the insulating layer to separate the first electrodes; A second electrode of a metal material applied to the entire surface of the transparent substrate; An organic light emitting layer formed between the first electrode and the second electrode to emit light by an externally applied voltage; A seal cover plate formed in a plane to seal the EL layer, A hygroscopic film formed on the seal cover plate to absorb a moisture component generated by releasing gas from the insulating film or the partition wall; And a seal material formed to a predetermined size or more to secure a space for adhering the seal cover plate and the transparent substrate and injecting an inert gas to prevent deterioration. The method of claim 1, And an spacer to prevent the partition wall from being damaged when the seal member is bonded by the seal member between the seal cover plate and the transparent substrate. The method of claim 2, The spacer is an organic electroluminescent device, characterized in that 20㎛ or more. The method of claim 1, The hygroscopic film is an organic electroluminescent device comprising any one of barium oxide (BaO), calcium carbonate (CaCO ₃ ), zeolite, zeolite, silica gel, and alumina. The method of claim 1, The moisture absorbing film is selectively deposited only in a region constituting the panel portion on the planar seal cover plate. The method of claim 1, The moisture absorbing film is an organic electroluminescent device, characterized in that deposited on the entire surface on the seal cover plate. The method of claim 1, The seal material is an organic electroluminescent device, characterized in that the ultraviolet curable resin. Forming an upper substrate for applying an electrical signal to display an image on the panel; Forming a seal cover plate such as glass to correspond to the upper substrate; Depositing a moisture absorbing film in the form of a thin film on the seal cover plate to absorb moisture from the upper substrate through a metal mask; And bonding the seal cover plate on which the moisture absorbing film is deposited and the upper substrate to form an organic electroluminescent device. The method of claim 8, The forming of the upper substrate may include forming a first electrode having a predetermined stripe pattern on the transparent substrate; Forming an insulating film on the first electrode to electrically insulate the first electrode; Forming a partition wall on the insulating layer to cross the first electrode; Applying an organic light emitting material to the transparent substrate; And forming a second electrode of a metal material on the front surface of the transparent substrate so that an electrical signal is applied to the organic light emitting material together with the first electrode. The method of claim 8, The step of depositing the moisture absorbing film is a method of manufacturing an organic electroluminescent device, characterized in that the moisture absorbing material having a hygroscopic property is deposited only on a portion constituting the front or panel portion of the seal cover plate by a sputtering or PECVD method. The method of claim 10, The hygroscopic material is any one of barium oxide (BaO), calcium carbonate (CaCO ₃ ), zeolite (zeolite), silica gel (silicagel), alumina (alumina) method of manufacturing an organic electroluminescent device. The method of claim 8, The bonding of the seal cover plate and the upper substrate may include forming a spacer having a thickness of 20 μm or more on both ends of the panel, which is thicker than the moisture absorption film having a thin film form. The method of manufacturing an organic electroluminescent device comprising the step of bonding the sealing material around the spacer.

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