JP2001176653A - Organic el element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain on organic EL element having a sufficient life and a structure which is simply and easily constructed with an improved sealing structure of an organic EL element, preventing a degradation by permeation of a moisture to organic EL element or oxygen. SOLUTION: Using a transparent substrate in which a film is formed on a substrate with a hydrophilic layer and a moisture preventing coat layer beforehand, a structure which covers an opposite side of the film side with an ultravoilet radiation cure type resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device using an organic EL element among display devices used for a display portion of a portable information device such as an electronic organizer and a mobile phone.
It relates to the moisture resistance and oxygen resistance of the L element.

[0002]

2. Description of the Related Art In recent years, self-luminous display elements for displaying an image by electroluminescence using an organic compound have been actively studied. So-called organic electroluminescence (hereinafter referred to as organic E)
L), which has several advantages, unlike liquid crystal display devices using liquid crystals. One is that it can emit light without a backlight because it emits light. In addition, since the structure is extremely simple, a thin, compact and lightweight display device can be provided. Further, the power consumption used for display is small, and it is suitable for a display device of a small information device such as a mobile phone which performs display using a battery.

FIG. 8 is a sectional view showing a schematic structure of a conventional organic EL device. An organic EL layer 3 is provided on the transparent electrode 2 provided on the transparent glass substrate 1a. Further, a metal electrode 4 is provided on the organic EL layer 3. Normally, an oxide of indium and tin called ITO is used for the transparent electrode 2 and serves as a source of holes as an anode. An alloy such as magnesium and silver is used for the metal electrode 4 and serves as a source of electrons as a cathode. Organic EL layer 3
Is generated when these holes and electrons are injected into the organic EL layer 3 and recombined. In general, a hole transport layer is provided between the organic layer 3 and the transparent electrode 2 (anode) and an electron transport layer is provided between the organic layer 3 and the metal electrode 4 (cathode) so that this reaction easily occurs. It is provided as a part of the layer 3.

Further, since the organic EL layer 3 reacts extremely sensitively to moisture and oxygen and deteriorates, a moisture absorbing layer 5 having a water absorbing property is provided on the inner surface of the transparent glass substrate 1b as an opposite substrate. For the moisture absorbing layer 5, an alkaline earth metal such as barium oxide BaO, calcium metal Ca, and calcium oxide CaO, and an oxide thereof are used. Furthermore, the sealing agent 6
Completely seals the surroundings. The organic EL layer 3 usually has a glass transition point of 100 ° C. or lower in many cases, and is weak to heat. Therefore, an ultraviolet curable resin is used as the sealant 6.

[0005] Japanese Patent Application Laid-Open No. 5-101883 discloses that a substrate on which an organic EL layer is formed is a laminate of a small moisture-permeable film and a water-absorbing polymer in order to prevent the organic EL layer from absorbing moisture. A sealing structure for covering with a moisture-proof polymer film has also been proposed. The water-absorbing polymer, which is a component of the moisture-proof polymer film, passes through the other component, which is a small moisture-permeable film, and traps a small amount of water that has entered the organic EL element, thereby forming an organic EL layer 3.
It is a proposal to have a role of preventing the arrival of moisture up to.

[0006]

As described above, in the organic EL element, special attention and study have been made on measures for preventing intrusion of moisture and oxygen. In general, organic EL materials such as quinacridone derivatives and triphenyldiamine, which are organic compounds used in the organic EL layer 3 as a light emitting layer, are extremely easy to react with moisture and oxygen, and display defects such as so-called dark spots occur and grow. Therefore, there is a problem that the life of the organic EL element is shortened.

As described above, various ideas and devices have been devised to solve these problems. However, in each case, problems such as a complicated structure and a heavy economic burden remain. Was. Generally, the cause of deterioration of the organic EL element is considered to be a problem of the organic material itself, a problem of infiltration of moisture or oxygen from the environment into the organic EL element, a problem relating to a manufacturing process, and the like. The problem of the organic material itself is that the interface between the transparent electrode 2 and the organic EL layer 3 and the organic EL layer 3 and the metal electrode layer 4
There is a problem in that the thin film organic material itself deteriorates due to thermal stimulus, electrical stimulus, or the like, in terms of the adhesion and the uniformity of contact at each interface such as the interface with the interface. These have made rapid progress in recent years due to improvements in organic materials and manufacturing methods.

The present invention proposes a structure for minimizing the influence of moisture and oxygen from the latter environment, which has a greater effect on the life of the organic EL device than the former, and preventing the deterioration of the organic EL device.

[0009]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a composite film comprising a transparent plastic film as a base film, a hydrophilic layer containing a moisture absorbent on the surface thereof, and a moisture-proof coating layer on the surface. Using the film as a substrate,
It has been found that the above problem can be solved by a simple structure in which a transparent electrode, an organic EL light emitting layer, a metal electrode and a protective layer are sequentially provided thereon.

That is, a transparent substrate having a transparent electrode formed on one surface, an organic EL layer formed on the transparent electrode, a metal electrode formed on the organic EL layer, and a part of the transparent electrode And a protective layer covering the organic EL layer and the metal electrode, a hydrophilic layer containing a moisture absorbent provided on the other surface of the transparent substrate, and a moisture-proof coating layer. Further, a protective layer was formed of an ultraviolet curable resin.

The protective layer is composed of a multilayer insulating film.
Further, the protective layer includes a first protective film formed of an insulating film covering a part of the transparent electrode, the organic EL layer, and the metal electrode, and an ultraviolet curable resin provided on the first protective layer. And a second protective layer. Further, a configuration is adopted in which a metal thin film is provided between the first protective layer and the second protective layer.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the organic EL device of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory sectional view showing an embodiment of the organic EL light emitting device of the present invention. As shown in FIG. 1, on a transparent film substrate 1, a transparent electrode 2, an organic EL layer 3, and a metal electrode 4 are formed.
Then, a protective layer 7 is provided so as to cover these. The protective layer prevents moisture and the like from entering from this side. Further, on the other surface of the transparent film substrate 1, a hydrophilic layer 8 and a moisture-proof coating layer 9 are laminated. The hydrophilic layer 8 and the moisture-proof coat layer 9 prevent moisture from entering the transparent film substrate. Even providing the moisture-proof coating layer 9 can prevent moisture from entering the transparent film substrate to some extent. However, the moisture-proof coating layer alone cannot prevent the moisture that has entered the bonding interface or the moisture that has entered the moisture-proof coating layer from entering the transparent film substrate. Therefore, a configuration was adopted in which a hydrophilic layer was provided between the transparent film substrate and the moisture-proof coating layer. This traps moisture and oxygen that the hydrophilic layer has invaded,
It is possible to prevent moisture and oxygen from entering the transparent film substrate.

Further, by providing a moisture-proof coating layer or a hydrophilic layer also between the transparent electrode and the transparent film substrate, the danger of entry of moisture and the like into the organic EL layer from the transparent film substrate side is significantly reduced. it can. That is, the transparent film substrate generally has high water absorption, and therefore, absorbs a small amount of water even in the thickness direction of the substrate. Therefore, even if a moisture-proof coat layer or a hydrophilic layer is provided only on the back side, it is not possible to prevent moisture or the like that has entered from the side of the substrate from reaching the organic EL layer side. Therefore, as described above, a configuration is provided in which a moisture-proof coating layer or a hydrophilic layer is provided between the transparent electrode and the transparent film substrate.

Further, between the transparent electrode and the transparent film substrate, a hydrophilic layer and a moisture-proof coating layer may be provided in the same manner as on the back surface of the film substrate. FIG. 2 shows an outline of a cross section of the organic EL element having this configuration. With such a configuration, moisture or the like that has entered from the side surface or interface of the substrate is trapped by the hydrophilic layer, and the moisture-proof coating layer prevents movement of moisture or the like between the hydrophilic layer and the organic EL layer. And the life and reliability of the organic EL element are increased.

Further, the protective layer 7 may be formed of a multilayer film. If there is a pinhole or a crack in the protective layer, there is a risk that moisture or the like may enter therethrough. Therefore, it is necessary to use a protective layer in which pinholes and cracks are unlikely to occur.
Therefore, it is preferable to increase the thickness of the protective layer or to configure the protective layer by a multilayer thin film having high adhesion to each other. If the protective layer is composed of a multilayer film, even if pinholes or cracks occur in a single layer, the thin film of the other layer will secure the barrier property and prevent a serious influence on reliability. Can do things. Therefore, not only a multilayer film formed of thin films of different materials but also a multilayer film formed of a thin film of the same material a plurality of times is effective.

(Example 1) An organic EL device of this example will be described with reference to FIG. A hydrophilic layer 8 and a moisture-proof coating layer 9 are laminated on the outside of a transparent film substrate 1 using a polycarbonate film having a thickness of 100 μm, and a transparent electrode 2 is provided inside the transparent film substrate 1.
As the base film of the transparent film substrate, a transparent film such as a polyethylene terephthalate film, a polyether sulfone film, a polyarylate film, etc. can be used in addition to the polycarbonate film.

FIG. 3 is a sectional view showing the structure of the hydrophilic layer 8. The hydrophilic layer can be formed by dispersing the hygroscopic agent 10 in a solution of a hydrophilic substance in advance and coating the film on the film by a dipping method, a spin coating method, a screen printing method, or the like. The hydrophilic layer 8 has a role of trapping infiltrated moisture and oxygen, and can be used in a thickness of about 1 μm to several mm.

As the moisture absorbent, silica gel, activated carbon, molecular sieve, zeolite, activated alumina, calcium oxide, barium oxide, calcium metal, lithium metal, diatomaceous earth, montmorillonite, bentonite and the like can be used. Inorganic matter does not matter. Also,
Hydrophilic substance, polyvinyl alcohol, cellulosic,
At least one compound may be selected from compounds such as nylon, starch, and acrylic acid, thereby forming a hydrophilic layer.

Further, the surface of the hydrophilic layer 8 is coated with a solution in which water-repellent silica is dispersed in an ultraviolet curable resin in advance by a spinner method, a dipping method, a screen printing method, or the like, so that the moisture-proof coating layer 9 is formed. It is formed. Here, as the ultraviolet curable resin, a polymer resin such as an epoxy resin, an acrylic resin, or a urethane resin can be used. Of these, epoxy resins having low hygroscopicity are particularly preferred.

Further, in order to enhance the water repellency, water-repellent silica is added in an amount of from 1% by weight to 20% by weight based on the ultraviolet curable resin.
To some extent. This water-repellent silica has an average particle size of 3
Those having a large number of pores of about 8 μm to about 8 μm and having a specific surface area of up to 700 m ² / g (such as Sunsphere H-53 manufactured by Asahi Glass) were used. The epoxy-based UV-curable resin is a low-stress type and can cure UV light of 365 nm at about 3500 mj / cm ² (for example, 3027C made by Three Bond). The thickness of the moisture-proof coating layer 9 can be used from about 3 μm to about several mm.
Considering workability and UV curability, 5 μm to 50
About 0 μm is suitable.

The transparent electrode 2 is made of ITO having a surface resistance of 20 Ω / □ by sputtering or electron beam vacuum evaporation.
(Indium-Tin-Oxide, indium oxide doped with tin). In general, the difference in the state of the minute surface of ITO depending on the film forming method may affect the orientation of the thin film, or reduce the metal In in the thin film, thereby affecting the interface state with the organic EL layer 3. This time, there was almost no difference between the two, and in the present invention, the film was formed by the sputtering method.

FIG. 4 shows a cross-sectional structure of the transparent film substrate of this embodiment in which the hydrophilic layer 8 and the moisture-proof coating layer 9 are provided on one surface of the transparent film substrate 1 and the transparent electrode 2 is provided on the other surface. . In the organic EL device of the present invention, the transparent electrode 2
Was formed into a desired pattern by a photolithography method. An organic EL layer 3 is formed on the transparent electrode 2. The organic EL layer 3 is made of a hole transporting material such as triphenyldiamine TPD or NPD, and a host luminescent material such as aluminum quinolinol Alq ₃ as quinacdrine (green) and perylene (blue).
It has a structure in which an organic light-emitting layer doped with a guest dye and an electron transporting material such as aluminum quinolinol Alq ₃ and a silole derivative PySPy are laminated, and these layers are continuously formed by a vacuum evaporation method. It is formed.

Further, a metal electrode is formed by continuously vacuum-depositing an alloy layer of Mg-Ag, Mg-Al or the like on the organic EL layer 3. The metal electrode 4 can be formed in a desired pattern by using a stainless steel pattern mask during the vacuum deposition. After that, the protective layer 7 was removed in a vacuum chamber using an IT
The O electrode 2, the organic EL layer 3, and the metal electrode 4 were covered so as to cover them. The protective layer 7 is a UV-curable resin like the moisture-proof coat layer 9, and all high-molecular resins such as epoxy, acrylic and urethane can be used, but epoxy resins having small hygroscopicity are preferable. The protective layer 7 needs to have a certain thickness in order to prevent the organic EL layer 3 from entering from moisture or oxygen from the environment. For this reason, as the coating method of the protective layer 7, a coating method suitable for thick coating such as a screen printing method, a bar coater method, and a dispense method is suitable.

From the above findings, the protective layer 7, the hydrophilic layer 8,
By optimally setting the thickness of the moisture-proof coating layer 9, the penetration of moisture and oxygen can be prevented, so that the life is extended,
Reliability will be improved. Tables 1 to 3 below show changes in the luminance half-life depending on the combination of the thicknesses of the protective layer 7, the hydrophilic layer 8, and the moisture-proof coating layer 9. Table 1 shows the hydrophilic layer 8
Is a first study result in which the penetration of moisture and oxygen from the transparent film substrate 1 side was mainly evaluated when the thickness of the moisture-proof coating layer 9 was changed while fixing the protective layer 7 to 100 μm and the protective layer 7 to 200 μm. Table 2 shows that when the moisture-proof coating layer 9 was fixed at 10 μm and the protective layer 7 was fixed at 200 μm and the thickness of the hydrophilic layer 8 was changed, the penetration of moisture and oxygen mainly from the transparent film substrate 1 side was prevented. Table 3 shows the results of the second evaluation, which were mainly performed on the protective layer 7 side when the hydrophilic layer 8 was fixed at 100 μm and the moisture-proof coating layer 9 was fixed at 10 μm to change the thickness of the protective layer 7. It is the third examination result which evaluates the invasion of moisture and oxygen from water.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

Here, the hydrophilic layer 8 of the transparent film substrate 1
Used was a dispersion prepared by dispersing and mixing a calcium oxide hygroscopic agent 10% in a polyvinyl alcohol solution at a solid content weight ratio of 10%. The moisture-proof coating layer 9 was prepared by dispersing and mixing 3% by weight of water-repellent silica (Sunsphere H-53 manufactured by Asahi Glass) in an ultraviolet-curable epoxy adhesive (3027 manufactured by Three Bond). The organic EL layer 3 used triphenyldiamine TPD for the hole transport layer, aluminum quinolinol Alq3 for the host light emitting material, and quinacridone (green) for the guest dye. The metal electrode layer 4 used Mg-Ag.

The test conditions of the moisture-proof property were performed in a constant temperature and high humidity environment of 40 ° C. and 90% RH by driving the organic EL element.
DC voltage 5 with transparent electrode 2 as anode and metal electrode 4 as cathode
V was applied and the luminance was evaluated at a current of about 3 mA / cm ² . The luminance was measured at a distance of 70 cm from the transparent film substrate using a luminance meter BM-7 manufactured by Minolta. Although the initial luminance was 100 cd / cm ^2, it was 50 cd / cm ^2.
The evaluation was performed based on the half-life time until the luminance decreased.

From these results, it was assumed that the precondition was 40 ° C., 90%
Approximately 50 hours in half in consideration of the acceleration of life degradation of RH environment
The above was found when the pass level in practical use was set to 0 hours or more. The film thickness of the moisture-proof coating layer 9 in which the hydrophilic layer 8 is fixed at 100 μm and the protective layer 7 is fixed at 200 μm is preferably 5 μm or more.

The moisture-proof coating layer 9 is 10 μm, and the protective layer 7
Is fixed to 200 μm, the thickness of the hydrophilic layer 8 is preferably 3 μm or more. 100 μm for the hydrophilic layer 8 and 10 μm for the moisture-proof coating layer 9
When fixed to m, the thickness of the protective layer 7 is preferably 20 μm or more. To summarize the above, it is preferable that the thickness of the moisture-proof coating layer 9 is 5 μm or more, the thickness of the hydrophilic layer 8 is 3 μm or more, and the thickness of the protective layer 7 is 20 μm or more.
The hydrophilic layer 8 and the moisture-proof coat layer 9 have properties complementary to each other, and are not limited to these values.

Example 2 FIG. 5 shows the structure of an organic EL device according to this example. This embodiment is different from the first embodiment based on FIG. 1 described above in that the protective layer is composed of two types of protective layers. In this embodiment, SiO ₂ is provided as a first protective layer covering the organic EL layer, and an ultraviolet curable resin is provided thereon as a second protective layer. As described in the first embodiment, the thicker the protective layer, the more the penetration of moisture and the like can be prevented. However, since the metal oxide film such as SiO ₂ is difficult to thickening of having a high barrier property against moisture and oxygen than the UV-curable resin, only a single layer of SiO ₂ realization of the organic EL device Is difficult. Therefore,
First, a thin film S is formed so as to cover the organic EL layer 3 and the metal electrode 4.
An insulating film (first protective layer) such as iO ₂ is formed.
By providing a resin (second protective layer) that can be easily thickened on the iO ₂ layer, a highly reliable organic EL element can be realized.

As described above, important characteristics of the first protective layer are to have an insulating property so that it can be formed on the metal electrode 4 and to have a sufficient barrier property in a thin film state. The important properties of the second protective layer are that it has a barrier property against moisture and oxygen and that it is easy to form a thick film. Therefore, the first protective layer includes SiO ₂ , T
A metal oxide such as iO ₂ is suitable, and a polymer resin such as an epoxy-based, acrylic-based, or urethane-based resin is suitable for the second protective layer. Further, in consideration of productivity, an ultraviolet curable resin is optimal.

Further, by providing a metal thin film between the first protective layer and the second protective layer, penetration of moisture and the like can be prevented,
The reliability of the organic EL element can be improved. The metal thin film has a high barrier property against moisture and oxygen, similarly to the above-described metal oxide film. However, since it is conductive, it cannot be provided so as to directly cover the metal electrode 4. Therefore, an insulating thin film may be provided so as to directly cover the organic EL layer and the metal electrode, and the metal thin film may be provided on the insulating thin film. Further, by providing a second protective layer on the metal thin film,
The total thickness of the protective layer can be reduced while maintaining reliability. At this time, the above-mentioned SiO ₂ , TiO ₂
Use of a metal oxide such as that described above has a further effect. In addition, a stable metal other than metals such as Al and Cr can be used for the metal thin film. The barrier properties can be further improved by using a multilayered metal thin film.

Example 3 FIG. 6 shows the structure of an organic EL device according to this example. FIG. 7 shows the configuration of the transparent film substrate used here. A transparent substrate in which a hydrophilic layer 8 and a moisture-proof coating layer 9 are provided on both sides of a 75 μm polyethylene terephthalate (PET) film as in Example 1, and a transparent electrode 2 (ITO) is provided on one of the moisture-proof coating layers Was used. The transparent electrode 2 provided on one side of this transparent substrate was patterned to form an anode of the organic EL device of the present invention.

In the same manner as in Example 1, the hydrophilic layer 8
A mixture prepared by dispersing and mixing a calcium oxide hygroscopic agent 10% in a polyvinyl alcohol solution at a solid content weight ratio of 10% was used. The moisture-proof coating layer 9 was prepared by dispersing and mixing 3% by weight of water-repellent silica (Sunsphere H-53 manufactured by Asahi Glass) with an ultraviolet-curable epoxy adhesive (3027 manufactured by Three Bond). As the organic EL layer 3, triphenyldiamine TPD was used for the hole transport layer, aluminum quinolinol Alq3 was used for the host luminescent material, and quinacridone (green) was used for the electron transport layer for the guest dye. Mg-Ag was used for the metal electrode 4.

After that, the transparent electrode 2 at a portion to be an external electrode
Except for the above, a first protective film 17 was formed by continuously depositing SiO ₂ having a thickness of 0.2 μm and Al having a thickness of 2.0 μm after forming the metal electrode 4 by vacuum deposition. Thereafter, it was taken out from the vacuum chamber, and an ultraviolet-curable epoxy adhesive was provided as the second protective film 27 in the same manner as in Example 1. Table 4 shows the results of evaluating the deterioration of the organic EL device of the present invention in the same manner as in Example 1 by changing the thickness of the second protective film.

[0038]

[Table 4]

As a result, the above was confirmed. By providing SiO ₂ and Al as the first protective film, the thickness of the second protective film, at which the life of the organic EL device of the present invention becomes an acceptable level for practical use, is 5 μm or more,
It was found that the film could be made thinner than in Example 1. By providing the first protective film, it is possible to form the second protective film out of the vacuum chamber to the outside, so that workability can be improved.

[0040]

As described above, according to the present invention, with a simple structure and a combination of general materials, organic EL light emission due to intrusion of moisture and oxygen into the element, which has been a problem of the organic EL element, is achieved. Deterioration of the layer and shortening of the life of the organic EL element due to this are greatly improved. This is an invention in which the organic EL element sufficiently satisfies the display life required for a display device for a portable information device such as an electronic organizer or a mobile phone used as a display, and can contribute industrially.

Further, the organic EL device of the present invention has an extremely simple structure, so that expensive capital investment can be avoided.
A low-cost organic EL device can be realized by enabling a process with a small number of manufacturing steps. Further, the structure of the organic EL device of the present invention can be applied not only to a display but also to a display.
Application as a backlight of a liquid crystal display device is also possible.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an organic EL device of the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of another embodiment of the organic EL device of the present invention.

FIG. 3 is a cross-sectional view illustrating an outline of a hydrophilic layer of the present invention.

FIG. 4 is a cross-sectional view illustrating a configuration of a transparent film substrate used in one embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration of another embodiment of the organic EL device of the present invention.

FIG. 6 is a cross-sectional view illustrating an outline of an organic EL device according to an embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a configuration of a transparent film substrate used in one embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating an outline of a conventional organic EL element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent film substrate 2 Transparent electrode layer 3 Organic EL layer 4 Metal electrode layer 5 Hygroscopic layer 6 Sealant 7 Protective layer 8 Hydrophilic layer 9 Moisture-proof coat layer 10 Hygroscopic agent

Continued on the front page (72) Inventor Mitsuru Suginoya 1-8 Nakase, Mihama-ku, Chiba-shi, Chiba F-term (reference) in Seiko Instruments Co., Ltd.

Claims (10)

[Claims] A transparent substrate on which a transparent electrode is formed; an organic EL layer formed on the transparent electrode;
An organic EL device having a metal electrode formed on a layer, wherein the transparent substrate is a composite film including a base film, a hydrophilic layer containing a moisture absorbent, and a moisture-proof coat layer, An organic EL device comprising: a protective layer that covers a part of an electrode, the organic EL layer, and the metal electrode.
L element. 2. The organic EL device according to claim 1, wherein the protective layer is a UV-curable resin. 3. The organic EL device according to claim 1, wherein the protective layer is formed of a multilayer insulating film. 4. The protection layer according to claim 1, wherein the protection layer includes a first protection film including an insulating film covering a part of the transparent electrode, the organic EL layer, and the metal electrode; 2. The organic EL device according to claim 1, further comprising: a second protective layer including an ultraviolet curable resin provided. 5. A metal thin film is provided between said first protective layer and said second protective layer.
3. The organic EL device according to claim 1. 6. The method according to claim 5, wherein the metal oxide of the first protective layer contains at least one of silicon dioxide and titanium dioxide, and the metal thin film contains at least one of aluminum and chromium. The organic EL device according to the above. 7. The method according to claim 1, wherein the base film is a transparent plastic film made of any one of a polycarbonate film, a polyethylene terephthalate film, a polyether sulfone film, and a polyarylate film. The organic EL device according to claim 1. 8. The organic EL device according to claim 1, wherein the hygroscopic agent contains a hygroscopic inorganic material or organic material. 9. The method according to claim 1, wherein the hydrophilic layer contains at least one polymer material selected from the group consisting of polyvinyl alcohol, cellulose, nylon, starch, and acrylic acid. The organic EL device according to the above. 10. The method according to claim 1, wherein the moisture-proof coating layer is an ultraviolet curable resin containing at least one of an epoxy polymer, an acrylic polymer, and a urethane polymer. 2. The organic EL device according to claim 1.