JP2813495B2 - Organic EL element sealing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sealing an electroluminescent device (EL device), and more particularly to a method for sealing an organic EL device.
The present invention relates to a method for sealing an element.

[0002]

BACKGROUND ART EL elements include an inorganic EL element and an organic EL element. Both EL elements are self-luminous and have high visibility, and since they are completely solid elements, they have excellent impact resistance. Easy to handle. For this reason, research and development and practical application as pixels for graphic displays, pixels for television image display devices, and surface light sources are being promoted. The organic EL element is composed of a light emitting layer made of a fluorescent organic solid such as anthracene and a hole injection layer made of a triphenylamine derivative, or an electron injection layer made of a light emitting layer and a perylene derivative, or a hole injection layer made of a perylene derivative. A laminated structure in which a layer and an electron injection layer are interposed between two electrodes (the electrode on the light emitting surface side is a transparent electrode) is generally formed on a substrate.

[0003] Such an organic EL element utilizes light emission generated when electrons and holes injected into the light emitting layer recombine. For this reason, the organic EL element has an advantage that it can be driven at a low voltage of, for example, 4.5 V and has a quick response by reducing the thickness of the light emitting layer, and has a high luminance EL because the luminance is proportional to the injection current. This has the advantage that an element can be obtained. By changing the type of fluorescent organic solid used as the light emitting layer, blue,
Light emission is obtained in all colors of green, yellow and red.
Organic EL elements have such advantages, in particular, that they can be driven at a low voltage.
Research for practical use is underway.

[0004] Incidentally, a fluorescent organic solid which is a material of a light emitting layer of an organic EL element is vulnerable to moisture, oxygen and the like. Also,
An electrode provided directly on a light emitting layer or through a hole injection layer or an electron injection layer (hereinafter, sometimes referred to as a counter electrode) tends to deteriorate in characteristics due to oxidation. For this reason, when the conventional organic EL element is driven in the atmosphere, the light emission characteristics are rapidly deteriorated. Therefore, in order to obtain a practical organic EL element or an organic EL device, the element is sealed so that moisture and oxygen do not enter the light emitting layer and the counter electrode is not oxidized to extend the life. It is necessary to plan.

However, regarding the organic EL device,
An effective sealing method has not yet been developed. For example, a method of sealing an inorganic EL element, that is, a method of providing a back glass plate outside a back electrode (counter electrode) and sealing silicone oil between the back electrode and the back glass plate is referred to as an organic E method.
When applied to the L element, the silicone oil penetrates the light emitting layer through the counter electrode or through the counter electrode and the hole injection layer or the electron injection layer, and the silicone oil modifies the light emitting layer. As a result, the light emitting characteristics of the organic EL element are significantly deteriorated or no light is emitted. Further, when a resin coating layer provided for mechanical protection or the like is applied to encapsulation of an organic EL element, a resin coating solution (generally, a solvent is a halogen-based solvent such as tetrahydrofuran, chloroform, dichloromethane, or the like) Since the luminescent layer is dissolved by the aromatic hydrocarbon solvent such as benzene, xylene, and toluene as described above, the luminescent characteristics of the organic EL element are significantly deteriorated or do not emit light at all.

In this trend of the development of organic EL devices, the present inventors have proposed a long-life organic EL device by coating the above-mentioned laminated structure with a specific fluorine-based polymer thin film.
A device was successfully obtained, and a patent application was filed for this organic EL device (Japanese Patent Application No. 2-33645).
No. 0, Japanese Patent Application No. 2-409017, Japanese Patent Application No. 3-1298
No. 52. Hereinafter, these may be collectively referred to as the organic EL device of the prior application. ).

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of sealing an organic EL device, which can produce an organic EL device having a longer life than the organic EL device of the prior application.

According to the method of the present invention for achieving the above object, a laminated structure having at least a light emitting layer made of a fluorescent organic solid interposed between two electrodes facing each other is provided on a substrate. the outer surface of the laminated structure of the organic EL device, after providing the protective layer comprising the aforementioned <br/> electrically insulating polymer compound under a set of vacuum environment followed by the formation of the light-emitting layer, the protective A shield layer made of one selected from the group consisting of an electrically insulating glass, an electrically insulating polymer compound, and an electrically insulating airtight fluid is provided outside the layer.

Hereinafter, the present invention will be described in detail. According to the method of the present invention, as described above, a protective layer is provided on an outer surface of a laminated structure in which at least a light-emitting layer made of a fluorescent organic solid is interposed between two electrodes facing each other. By providing a shield layer on the outside, the organic EL element is sealed. Here, the configuration of the laminated structure is as follows: electrode (cathode) / light-emitting layer / hole injection layer / electrode (anode) electrode (anode) / light-emitting layer / electron injection layer / electrode (cathode) electrode (anode) / Hole injection layer / light-emitting layer / electron injection layer / electrode (cathode) electrode (anode or cathode) / light-emitting layer / electrode (cathode or anode). The present invention can also be applied to an organic EL element having the same.
The shape, size, material, manufacturing method, and the like of these laminated structures are appropriately selected according to the use of the organic EL device, and the like. The material, the manufacturing method, and the like are not limited. However, in order to obtain a long-life organic EL element, it is desirable to suppress the deterioration of the characteristics of the light emitting layer during the formation process of the laminated structure as much as possible. It is particularly preferable to perform the treatment under a series of vacuum environments.

In the method of the present invention, first, a protective layer made of an electrically insulating polymer compound film is provided on the outer surface of the above-mentioned laminated structure. The protective layer may be provided at least on the main surface of the counter electrode, but is particularly preferably provided on the entire outer surface of the multilayer structure. Further, in an organic EL element in which a counter electrode is provided on a part of the main surface of any of a light emitting layer, a hole injection layer, and an electron injection layer, at least a layer serving as a base of the counter electrode is provided. It is preferable to provide a protective layer on a portion of the main surface of the substrate where no counter electrode is provided and on a main surface of the counter electrode.

The electrically insulating polymer compound as a material of the protective layer is formed by a physical vapor deposition method (hereinafter, sometimes referred to as a PVD method).
Can be formed by chemical vapor deposition (hereinafter referred to as CVD)
Any method can be used as long as it can be formed into a film by the method described above or is soluble in a fluorinated solvent such as perfluoroalcohol, perfluoroether, or perfluoroamine. Specific examples of each electrically insulating polymer compound include the following.

Electrically insulating polymer compound capable of forming a film by the PVD method: polyethylene, polypropylene, polystyrene, polymethyl methacrylate, polyimide (a product obtained by depositing and polymerizing two kinds of monomers on a substrate. Technical Journal, 1988, 30) , 22), polyurea (polymerized by depositing and polymerizing two types of monomers on a substrate; see Technical Journal, 1988, 30, 22), and JP-A-63-189.
No. 64, a fluorine-containing polymer disclosed in JP-A-63-22206, and a fluorine-containing polymer disclosed in JP-A-63-238115 Compound, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, fluorine-containing copolymer having a cyclic structure (Japanese Patent Application No. 3-129852) See).

[0013] CVD method [plasma polymerization method (plasma C
VD)], an electrically insulating polymer compound capable of forming a film by using polyethylene, polytetrafluoroethylene, polyvinyltrimethylsilane, polymethyltrimethoxysilane,
Polysiloxane and the like.

An electrically insulating polymer compound soluble in a fluorine-based solvent such as perfluoroalcohol, perfluoroether, perfluoroamine, etc. A fluorine-based polymer compound disclosed in JP-A-63-18964, Fluoropolymer compounds disclosed in JP-A-63-22206, JP-A-63-238
No. 115 fluorinated polymer compound,
Polychlorotrifluoroethylene, polydichlorodifluoroethylene, a copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, a fluorinated copolymer having a cyclic structure (see Japanese Patent Application No. 3-129852)
And other fluoropolymer compounds.

[0015] The protective layer depends on the polymer compound used.
Each PVD method (the above polymer compound), CVD method (the above polymer compound), can be provided by a casting method or spin coating method (the above polymer compound), as described later, the protective layer When forming the light emitting layer
It is particularly preferable to provide under a series of vacuum environments following
Therefore, it is desirable to provide by the PVD method or the CVD method.
Good. The thickness of the protective layer is preferably from 10 nm to 100 μm, although it depends on the material used and the forming method. When the side on which the protective layer is provided is used as the light emitting surface, the organic E
A material and a formation method are selected so that a protective layer having excellent transparency to EL light from the L element is obtained. The formation of the protective layer by each method can be performed, for example, as follows.

PVD method PVD methods include a vacuum deposition method (including a vapor deposition polymerization method),
Although a sputtering method or the like can be applied, it is particularly preferable to apply a vacuum evaporation method or a sputtering method. Note that the vacuum deposition method and the sputtering method can be subdivided, for example, as follows, and any of the methods can be applied. a. Vacuum evaporation method Resistance heating method, electron beam heating method, high frequency induction heating method, reactive evaporation method, molecular beam epitaxy method, hot wall evaporation method, ion plating method, cluster ion beam method, evaporation polymerization method, etc. b. Sputtering method Two-pole sputtering method, two-pole magnetron sputtering method, three-pole and four-pole plasma sputtering method, reactive sputtering method, ion beam sputtering method, etc. Deposition conditions vary depending on the raw material and the type of PVD method to be applied. In the case of the vapor deposition method (resistance heating method, electron beam heating method, high frequency induction heating method), the degree of vacuum before vapor deposition is generally 1 × 10 ⁻² Pa or less, preferably 6 × 10 ⁻³ Pa or less,
The heating temperature of the deposition source is generally 700 ° C. or less, preferably 600 ° C.
℃ or less, the substrate temperature is generally 200 ℃ or less, preferably 100
° C or lower and the deposition rate is preferably 50 nm / sec or less, more preferably 3 nm / sec or less.

CVD method Plasma polymerization in which gaseous monomers such as ethylene and propylene are polymerized by plasma is preferred. General pyrolysis C
VD is not suitable because the substrate temperature becomes high.

Casting method Raw materials are dissolved in a fluorinated solvent such as perfluoroalcohol, perfluoroether or perfluoroamine, and this solution is spread on a laminated structure, and then air-dried for 8 to 16 hours for protection. Get the layers. The drying time may be any time as long as it is 8 hours or more, but drying over 16 hours is not suitable because there is no great difference in the degree of drying. Usually, a drying time of about 12 hours is appropriate. The concentration of the raw material in the solution is appropriately selected according to the intended thickness of the protective layer.

Spin coating method The solution obtained in the same manner as in the above casting method was
~ 20,000 rpm, preferably 200 ~ 8000 rpm
An appropriate amount is dropped on the laminated structure rotating in the above, and the laminated structure is further kept as it is for 5 to 60 seconds, preferably 10 to
After rotating for 30 seconds, the protective layer is obtained by drying in the same manner as in the case of the casting method. At this time, the amount of the solution dropped depends on the laminated structure or the organic EL to be sealed.
Although it depends on the size of the element, 0.6 to 6 ml, preferably 0.5 to 3 m for a laminated structure or an organic EL element having a size of a normal slide glass (25 × 75 × 1.1 mm).
l. The concentration of the raw material in the solution is appropriately selected according to the thickness of the target protective layer, as in the case of the casting method, but the range is narrower than in the case of the casting method, and control of the film thickness and uniformity of the film are performed. From the viewpoint of properties and the like, the amount is 1 to 40 g / 100 ml, preferably 4 to 20 g / 100 ml.

In each of the casting method and the spin coating method, air drying is performed at 30 to 100 ° C., preferably 50 to 80 ° C., using a vacuum dryer or the like.
It is desirable to further dry for 4 hours, preferably 8 to 16 hours.

In order to obtain a long-life organic EL device,
It is desirable to suppress the deterioration of the characteristics of the light emitting layer and the counter electrode during the formation of the protective layer as much as possible.
It is particularly preferable to provide a protective layer by a vacuum method or a CVD method in a vacuum environment. For the same reason, it is particularly preferable that the steps from the formation of the light emitting layer constituting the laminated structure to the formation of the protective layer are performed in a series of vacuum environments.

In the method of the present invention, a shield made of one selected from the group consisting of an electrically insulating glass, an electrically insulating polymer compound, and an electrically insulating airtight fluid is provided outside the protective layer provided in this manner. Provide a layer. At this time, since the laminated structure is protected by the protective layer, various methods can be applied to the formation of the shield layer. Hereinafter, a method of forming the shield layer for each material will be described.

A. Electrically Insulating Glass After providing a protective layer on the outer surface of a laminated structure provided on a substrate such as a glass substrate, the electrical insulating glass is placed over the protective layer, and the edge of the substrate is covered. And the edge of the electrically insulating glass are bonded to each other with an adhesive or the like to provide a shield layer. The surface on the protective layer side of the electrically insulating glass is preferably a polished surface of a photomask grade. The glass preferably has a high alkali resistance and a high volume resistance (10 ⁷ Ωm or more at 350 ° C.). A specific example is Corning # 7059. This electrically insulating glass may be provided in direct contact with the protective layer, or may be provided outside the protective layer via a moisture absorbing layer made of polyvinyl alcohol, nylon 66, or the like. When a moisture absorbing layer is interposed, the moisture absorbing layer is preferably provided in advance on the surface of the electrically insulating glass. In this case, the glass surface may be a surface rougher than the photomask grade.

B. Electrically insulating polymer compound A shield layer is formed using, for example, the following method using an electrically insulating liquid resin or solid resin. Among the methods exemplified below, in the immersion method and the transfer molding method, the whole element (including the substrate when the laminated structure is provided on the substrate) is covered with the shield layer, so that the sealing is performed. The material of the shield layer is selected so that practically sufficient translucency for the EL light from the organic EL element to be obtained is obtained. In another method, when the laminated structure is provided on the substrate, the shield layer can be formed only on the surface on the protective layer side, so that the surface on the protective layer side is not used as the light emitting surface. As far as possible, it is not necessary to consider the translucency of the shield layer.

1. When a liquid resin is used: Casting method: In this method, an organic EL device provided with a protective layer (hereinafter, sometimes referred to as a device with a protective layer) is placed in a mold container, and the inside of the mold container is removed. Inject the liquid resin to which a catalyst and a curing agent have been added, cover the surface of the element with a protective layer on the protective layer side with this liquid resin, cure and release it, and then completely cure it in an oven. Provide a shield layer. More preferably, after the curing and release, the composition is cured in a temperature-controlled oven. The liquid resin in this case may be a thermosetting type or a photocuring type as long as it is electrically insulating (hereinafter sometimes referred to as condition (i)), but when the surface on the protective layer side is a light emitting layer, Has practically sufficient translucency for EL light from the organic EL element to be sealed (hereinafter, condition (ii)
A resin layer can be obtained.
As for the thermosetting resin, it is preferable to use a resin having a curing temperature lower than the softening point of the electrically insulating polymer compound forming the protective layer (hereinafter, may be referred to as condition (iii)).

Among the thermosetting liquid resins satisfying the conditions (i) and (ii), particularly preferred are epoxy resins, silicone resins, epoxy silicone resins, phenol resins, diacryl phthalate resins, alkyd resins and the like. In practical use, it is appropriately selected depending on whether or not the condition (iii) is satisfied. The photocurable liquid resin satisfying the conditions (i) and (ii) is BY-300B
(Trade name of en-thiol-based photo-curable liquid resin, manufactured by Asahi Denka Co., Ltd.), BU-230U (trade name of acrylic-based photo-curable liquid resin, manufactured by Toa Gosei Chemical Co., Ltd.), UV1001 (polyester-based light UV-curable resin such as a product name of a curable liquid resin (manufactured by Sony Chemical Co., Ltd.), and LCR000
(Trade name, manufactured by IC Japan Co., Ltd.) and the like. The curing temperature and curing time of these liquid resins differ depending on the resin. For example, when a thermosetting epoxy resin is used, the
2 minutes. It is more preferable to add a deaeration step in vacuum after adding a catalyst or a curing agent to the resin for both thermosetting and photocuring liquid resins.

Vacuum potting method: In this method, a shield layer is provided by performing all the steps of the casting method described above in a vacuum. This is a more preferable method than the casting method.

Immersion method: In this method, the element with a protective layer is immersed in the liquid resin described above and then pulled up, and then the liquid resin liquid attached to the element with the protective layer is cured by heat treatment or air drying. Provide a shield layer. As the resin, various thermoplastic resins, thermosetting resins or photocurable resins can be used as long as they satisfy the conditions (i) and (ii).

Others: A shield layer may be provided by applying a liquid resin to the surface of the element with a protective layer on the protective layer side using a spatula or the like and then curing the liquid resin. As the liquid resin, the above-described liquid resin can be used as it is, but when the surface on the protective layer side is not used as the light emitting surface, a liquid resin that does not satisfy the condition (ii) can be used.

2. When the solid resin is used in a liquid state • Hot melt method: In this method, a heat-melted resin is cast or vacuum potted to provide a shield layer. As the resin used in this method, the condition (i)
And a melting point lower than the softening point of the electrically insulating polymer compound forming the protective layer (hereinafter, may be referred to as condition (iv)).

Specific examples of the thermoplastic resin satisfying the condition (i) include polyvinyl chloride, polyvinyl bromide, polyvinyl fluoride, vinyl chloride-vinyl acetate copolymer, vinyl chloride
Ethylene copolymer, vinyl chloride-propylene copolymer,
Vinyl chloride-vinylidene chloride copolymer, vinyl chloride-butadiene copolymer, vinyl chloride-acrylate copolymer, vinyl chloride-acrylonitrile copolymer, vinyl chloride-styrene-acrylonitrile terpolymer, chloride Vinyl-vinylidene chloride-vinyl acetate copolymer, polyvinylidene chloride, polytetrafluoroethylene, polyvinylidene fluoride, polychlorotrifluoroethylene, a fluorine-based polymer compound disclosed in JP-A-63-18964, Fluorinated polymer compounds disclosed in Japanese Unexamined Patent Publication No. 63-22206;
No. 15, a halogenated vinyl polymer or a vinyl halide copolymer such as a fluorine-containing polymer compound;

[0032] Polyvinyl alcohol, polyallyl alcohol, polyvinyl ether, polyallyl ether, etc.
Polymer of unsaturated alcohol or unsaturated ether or copolymer of unsaturated alcohol and unsaturated ether; polymer or copolymer of unsaturated carboxylic acid such as acrylic acid or methacrylic acid; polyvinyl such as polyvinyl acetate Polymers or copolymers having unsaturated bonds in alcohol residues, such as esters and polyacrylic esters such as polyphthalic acid; polyacrylic esters, polymethacrylic esters, maleic ester polymers, and fumaric ester polymers Such as a polymer or copolymer having an unsaturated bond in an acid residue or in an acid residue and an alcohol residue;
Acrylonitrile polymer, methacrylonitrile polymer, copolymer of acrylonitrile and methacrylonitrile, polyvinylidene polycyanide, malononitrile polymer, fumarononitrile polymer, copolymer of malononitrile and fumarononitrile;

Polystyrene, poly α-methylstyrene,
Polymers or copolymers of aromatic vinyl compounds such as poly-p-methylstyrene, styrene-p-methylstyrene copolymer, polyvinylbenzene, polyhalogenated styrene; polyvinylpyridine, poly-N-vinylpyrrolidine, poly-N A polymer or copolymer of a heterocyclic compound such as vinylpyrrolidone; a polyester condensate such as polycarbonate or a polyamide condensate such as nylon 6 or nylon 66; an imide compound of maleic anhydride, fumaric anhydride, or maleic anhydride Of one substance selected from the group consisting of imide compounds of fumaric anhydride and fumaric anhydride, or copolymers of at least two substances selected from the group; polyamides, polyetherimides, polyimides, and polyphenylene oxides , Polyphenylene sulfide, polysulfone, polyether Rusuruhon, heat resistant polymer compound of polyarylate, polyethylene, polypropylene,
Polyethylene terephthalate, polymethyl methacrylate, thermotropic liquid crystal polymers disclosed in JP-A-2-253952; and the like, and in practical use, are appropriately selected depending on whether or not the condition (iv) is satisfied.

Fluid immersion method: A container provided with a microporous bottom plate, a porous bottom plate, and an air (compressed air) reservoir below the porous bottom plate is used.
When a solid resin (powder resin) crushed to a size of 300 mesh is placed and compressed air is flowed from below through a porous bottom plate, the powder resin can be treated like a fluid. Therefore, in this method, the container with the compressed air flowing through the powder resin is tilted, and the element with the protective layer heated to a temperature equal to or higher than the softening point of the powder resin is put into the container, and the heated protective layer A shield layer is provided by melting and adhering a powder resin to the attached element. As the resin used in this method, the thermoplastic resin exemplified in the description of the hot melt method is preferable.

Transfer molding method: In this method,
The element with a protective layer is placed in a mold (having a small hole), and the resin melted in the pot is fed into the cavity of the mold through the small hole and cured to provide a shield layer. The resin used in this method is preferably a thermoplastic resin exemplified in the description of the hot melt method and satisfying the above condition (ii).

Others: The shield layer may be provided by applying a resin solution to the surface of the element with a protective layer on the protective layer side, and then volatilizing the solvent in the resin solution by heat treatment or air drying. In this case, the resin satisfies at least condition (i) when the surface on the protective phase side is not used as the light-emitting surface, and is compatible with any of solvents such as a halogen-based solvent, an aromatic hydrocarbon-based solvent, and a fluorine-based solvent. It only has to be soluble. Preferred resins include acrylic resins and polystyrene. Further, an organic solvent volatilization type adhesive is also one of preferred examples,
Specifically, 1001B (trade name of an elastomer-based organic solvent volatile adhesive, manufactured by Zeon Corporation) and SG4693
(Trade name of an organic solvent-evaporating adhesive, manufactured by 3M).

3. Film Sealing In this method, a shield layer is provided by covering the element with a protective layer with a polymer film. In this case, the whole of the device with a protective layer (including the substrate in the case of a device with a protective layer in which a laminated structure is provided on a substrate) may be covered with a polymer film, or the laminated structure may be provided on a substrate. In such a device with a protective layer, only the surface on the protective layer side of the device with a protective layer may be covered with a polymer film. When covering the entire device with a protective layer with a polymer film, a polymer fill is placed over the device with a protective layer from above and below, and the upper and lower polymer films are thermally fused to each other along the edge of the device with a protective layer. . When only the surface on the protective layer side is covered with the polymer film, the edge of the polymer film and the substrate are bonded with an adhesive or the like, or when the laminated structure is provided on the polymer substrate. Thermally bonds the edge of the polymer film to the substrate.

The material of the polymer film depends on the conditions (i) and (i)
Polymer compounds satisfying i) are preferred. As a specific example,
Polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polystyrene, polyethersulfone, polyarylate, polycarbonate, polyurethane, acrylic resin, polyacrylonitrile, polyvinyl acetal, polyamide, polyimide,
Examples include diacryl phthalate resin, cellulosic plastic, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, and copolymers of two or more of these. Particularly preferred polymer films include polyvinyl fluoride, polychlorotrifluoroethylene,
Polytetrafluoroethylene, JP-A-63-18964
Fluoropolymer disclosed in JP-A-63-22206, Fluorinated polymer disclosed in JP-A-63-238115 And those obtained by forming a polymer compound having a small water vapor transmission rate into a film by a method such as stretching. The polymer film covering the surface other than the light emitting surface of the element with a protective layer may not satisfy the condition (ii).

The polymer film used at this time may be a single layer, but it is more preferable to use a polymer film having a multilayer structure provided with a moisture absorbing layer made of nylon 66, polyvinyl alcohol or the like. The polymer film having a multilayer structure provided with a moisture absorbing layer is used such that the moisture absorbing layer is at least in contact with the protective layer.

C. Electrically insulating airtight fluid A protective layer was provided together with a gas or liquid satisfying the condition (i) in a container such as a glass container, a ceramics container and a plastic container satisfying the above condition (i). A shield layer is provided by enclosing an organic EL element (element with a protective layer). When the container wall and the airtight fluid are also positioned outside the light emitting surface of the element with a protective layer, these conditions are set as described above (i.
i) must also be satisfied. In an element with a protective layer in which a laminated structure is provided on a substrate, the substrate may be used as a part of the container. The container is formed by bonding necessary members to each other with low-melting glass, solder, epoxy resin for hermetic sealing, or the like. As the gas to be sealed in the container, an inert gas such as He gas, Ar gas, Ne gas or the like is preferable. As the liquid, silicone oil or the like is preferable. When the substrate is used as a part of the container and the liquid is sealed in the container, assuming that the protective layer side of the device with the protective layer is not used as the light emitting surface, a moisture absorbing material such as silica gel or activated carbon is mixed. You may.

By providing the protective layer and the shield layer as described above, the penetration of moisture and oxygen into the light emitting layer is suppressed by these layers, thereby extending the life of the organic EL element.

[0042]

Embodiments of the present invention will be described below with reference to the drawings. Example 1 A glass plate having a size of 25 × 75 × 1.1 mm [HOYA
White plate glass manufactured by Co., Ltd.] as a substrate, and an ITO film having a thickness of 100 nm was formed on this substrate to form a transparent electrode (hereinafter, the substrate on which the ITO film was formed is referred to as a transparent support substrate). . The transparent support substrate was ultrasonically cleaned with isopropyl alcohol for 30 minutes, then with pure water for 5 minutes, rinsed with isopropyl alcohol, and dried by blowing dry N ₂ gas. Finally, a UV ozone cleaning device [manufactured by Samco International Co., Ltd.]
Washed for minutes. The washed transparent supporting substrate was fixed to a substrate holder of a commercially available vacuum evaporation apparatus [manufactured by Nippon Vacuum Engineering Co., Ltd.], and N, N′-diphenyl-N, N′-bis- (3) was placed in a molybdenum resistance heating boat. -Methylphenyl)-[1,
1′-biphenyl] -4,4′-diamine (hereinafter referred to as TP
DA) and 200 mg of tris (8-quinolinol) aluminum (hereinafter referred to as Alq.) Purified by sublimation into another molybdenum resistance heating boat.
g, and the pressure in the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa.

Next, the resistance heating boat containing TPDA was heated to 215 to 220 ° C. to deposit TPDA on the ITO film at a deposition rate of 0.1 to 0.3 nm / s.
A hole injection layer having a thickness of 60 nm was formed. At this time, the substrate temperature was room temperature. Then, while the transparent support substrate on which the hole injection layer was formed was fixed to the substrate holder, Alq.
Is heated to 275 ° C., and the Alq. Was deposited on the hole injection layer at a deposition rate of 0.1 to 0.2 nm / s to form a light emitting layer having a thickness of 60 nm. The substrate temperature at this time was also room temperature. Next, a molybdenum resistance heating boat containing 1 g of magnesium in advance and a molybdenum resistance heating boat containing 500 mg of silver in advance are each heated to deposit magnesium at a deposition rate of about 1.5 nm / s. At the same time, silver was vapor-deposited at a vapor deposition rate of about 0.1 nm / s, and a 150-nm-thick electrode (counter electrode) made of a mixed metal of magnesium and silver was provided on the light-emitting layer. An organic EL element was obtained by providing an ITO film (electrode), a hole injection layer, a light emitting layer, and a counter electrode on a glass substrate.

Thereafter, the ITO provided on the glass substrate
Forming the hole injection layer and the light emitting layer on the outer surface of the layered structure including the film, the hole injection layer, the light emitting layer, and the counter electrode using the same apparatus as the vacuum evaporation apparatus used for forming the layered structure. , A protective layer was provided in the following manner under a series of vacuum environments. First, an alumina crucible containing 1.5 g of an amorphous copolymer powder of tetrafluoroethylene and perfluoro-2,2-dimethyl-1,3-dioxole (trade name: Teflon AF, manufactured by DuPont) as a vapor deposition source Was placed over a tungsten basket (on an alumina crucible) in which was previously placed a stainless steel mesh of 12 μmφ. Next, after the pressure in the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa, the tungsten source was electrically heated to heat the deposition source to 455 ° C., and the deposition rate was 0.5 nm / s on the outer surface of the laminated structure. 0.8 μm (800 nm)
Was provided with a Teflon AF thin film (protective layer). In addition, ITO
The thickness and deposition rate of each layer except for the electrodes were controlled while monitoring the thickness of the deposited film using a quartz-crystal vibrating thickness gauge [manufactured by Nippon Vacuum Engineering Co., Ltd.] arranged in a vacuum chamber. The thickness of each of the obtained layers was measured with a stylus-type film thickness meter, and it was confirmed that the thickness agreed with the reading of the quartz-crystal vibrating thickness meter.

Next, the organic EL device provided with the protective layer (hereinafter, sometimes referred to as a device with a protective layer) was taken out of the vacuum chamber, and a shield layer was provided outside the protective layer in the following manner. First, a film thickness of 350 was formed on one main surface as a moisture absorbing layer.
An electrically insulating glass substrate (a glass plate size of 25 × 75 × 1.1 mm) provided with a polyvinyl alcohol (hereinafter referred to as PVA) layer having a thickness of nm was prepared. This glass substrate is composed of 3% by weight of PVA powder, 0.5% by weight of hydrochloric acid and 9% by weight of water.
1 ml of a liquid mixed with 6.5% by weight was dropped on a slide glass, and the solution was mixed with a spin coater [manufactured by Mikasa Corporation].
After spin coating under the conditions of 00 rpm and 30 seconds, the resultant was air-dried for 8 hours, further placed in a vacuum drier (manufactured by Yamato Chemical Co., Ltd.) and dried at 60 ° C. for 10 hours. Next, an epoxy-based adhesive (trade name: Cemedine Spar 5, manufactured by Cemedine Co.) is applied to the edge of the surface on the PVA layer side of the glass substrate with a width of about 0.5 mm. Were superimposed. The superposition at this time is PVA
The test was performed so that the layer and the protective layer were in contact with each other. The epoxy adhesive was used after stirring the main agent and the curing agent 20 times with a spatula. Thereafter, the epoxy adhesive was cured in the air for 10 hours to provide a shield layer made of an electrically insulating glass plate.

Reference Example 1 An organic EL device was manufactured in exactly the same manner as in Example 1,
Once the vacuum environment of the vacuum deposition apparatus used to form the laminated structure is broken, the same device as the vacuum deposition apparatus used to form the laminated structure is used, and the following is applied to the outer surface of the laminated structure of the organic EL element. The protective layer was provided in the same manner as described above. First, an alumina crucible containing 1 g of high-density polyethylene (trade name: 440M, manufactured by Idemitsu Petrochemical Co., Ltd.) as a vapor deposition source is placed in a tungsten basket, and a stainless steel mesh of 12 μmφ is placed on the alumina crucible. I covered it. Next, the organic EL device obtained above was set on a sample holder, and the pressure in the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa. 0.5 nm on the outer surface of the structure
A high-density polyethylene thin film (protective layer) having a thickness of 0.3 μm (300 nm) was provided at a deposition rate of / s. Thereafter, the organic EL device provided with the protective layer was taken out of the vacuum chamber, and a shield layer was provided in the following manner. First, a main agent of an epoxy-based adhesive (trade name: Cemedine Spar 5, manufactured by Cemedine Co., Ltd.) and a curing agent were mixed with a spatula 20 times. Then, the mixture was put on a spatula and applied on the protective layer to a thickness of 2 mm. Thereafter, the epoxy adhesive was cured by being left in the air for 5 hours to provide a shield layer.

Example 2 As shown in FIG. 1, a glass plate 1 [white plate glass manufactured by HOYA CORPORATION] having a size of 25 × 75 × 1.1 mm was placed on a glass plate 1.
0 mm × 75 mm × 100 nm ITO films 2 a and 2
The device with the protective layer was obtained in the following manner using the film on which b was formed as the transparent support substrate 3. First, after masking the ITO film 2a, a hole injection layer and a light emitting layer were formed in exactly the same manner as in Example 1. Next, the mask applied to the ITO film 2a was removed using an automatic mask changing mechanism provided for the vapor deposition apparatus. Next, the ITO film 2 is formed by the above mechanism.
After masking the outer edge in the longitudinal direction of a over a width of 5 mm, a counter electrode and a protective layer were provided in exactly the same manner as in Example 1 to obtain a device with a protective layer. As shown in FIG. 2, in the element 4 with the protective layer thus obtained, two ITOs
A hole injection layer 5 is provided from the surface of the glass plate 1 between the films 2a and 2b to the main surface of the ITO film 2b, and the light emitting layer 6 is provided on the hole injection layer 5.
A counter electrode 7 is provided on the light emitting layer 6 and on a main surface of an inner half of the ITO film 2a.
Is provided with a protective layer 8 on the main surface thereof. In the element 4 with a protective layer, a laminated structure 9 is formed by the ITO electrode 2b, the hole injection layer 5, the light emitting layer 6, and the counter electrode 7. Thus, everything from the hole injection layer to the protective layer was manufactured under a series of vacuum environments.

Thereafter, the element 4 with the protective layer was taken out of the vacuum chamber, and a shield layer was provided in the following manner to obtain an organic EL element which had been sealed. First, the ITO film 2b
The hole injection layer 5, the light emitting layer 6, the counter electrode 7, and the protective layer 8 provided on the ITO film 2b were cut off over a width of 5 mm from the outer edge in the longitudinal direction. The width of the edge of the glass plate 1 in the width direction is 5 m so that the thickness is substantially the sum of the thickness of the glass plate 1 and the thickness of the ITO film.
m, the hole injection layer 5, the light emitting layer 6, the counter electrode 7, and the protective layer 8 were cut off.

Next, a glass plate having an 18 × 73 × 2 mm recess and a 2 mm diameter through hole (hereinafter referred to as an injection port) provided at the bottom of the recess (external dimensions: 20 × 75 ×
3 mm, hereinafter referred to as shield glass) was prepared, and the shield glass and the element 4 with a protective layer were bonded together with an epoxy-based adhesive (trade name: Cemedine Super 5, manufactured by Cemedine Co., Ltd.). The epoxy adhesive was mixed with the main agent and the curing agent, stirred with a spatula 20 times, and then applied to the edge of the element 4 with a protective layer in a rectangular shape having a width of 1 mm and a size of approximately 20 × 75 mm. The shield glass and the element 4 with a protective layer were bonded together such that the counter electrode 7 and the protective layer 8 were accommodated in the concave portion of the shield glass. After bonding, the epoxy-based adhesive was cured by being left in the air for 10 hours.

Next, 8 g of silica gel (particle size: 50 μm) for absorbing moisture was injected through an injection port provided in the shield glass.
Silicone oil dispersed in volume% [trade name: TSK4
51, manufactured by Toshiba Corporation. Hereafter called insulating oil]
The space formed by the concave portion of the shield glass and the element with a protective layer was filled with insulating oil. Thereafter, the injection port was closed with a glass lid to obtain an organic EL element provided up to the shield layer. The glass lid was adhered to the shield glass with the above-mentioned epoxy adhesive.

FIG. 3 schematically shows an end face of the organic EL device finally obtained. As shown in FIG. 3, the organic EL element 10 which has been subjected to sealing is provided with an I
TO film 2b, hole injection layer 5, light emitting layer 6, and counter electrode 7
And a protective layer 8 made of a Teflon AF thin film is provided on the outer surface of the multilayer structure 9. A shield layer 11 made of insulating oil is provided outside the protective layer 8, and a shield glass 13 bonded with an epoxy-based adhesive 12 to provide the shield layer 11 is provided outside the shield layer 11. Is located. The injection port 14 provided in the shield glass 13 is closed by a glass lid 16 adhered by an epoxy adhesive 15. The counter electrode 7 is also in contact with the ITO film 2a provided on the surface of the glass plate 1.

Comparative Example 1 An organic EL device was obtained in exactly the same manner as in Example 1, and this organic EL device was not provided with a protective layer and a shield layer.

Comparative Example 2 An organic EL device was obtained in exactly the same manner as in Example 1, and this organic EL device was provided with only a protective layer exactly as in Example 1.

Comparative Example 3 An organic EL device was obtained in exactly the same manner as in Example 1, and a cured layer of an epoxy-based adhesive was provided directly on the counter electrode of this organic EL device in the same manner as in Example 2.

Life Measurement The organic EL devices obtained in Example 1 , Example 2, Reference Example 1, and Comparative Examples 1 to 3 were allowed to stand in the air for 7 days. m ^2, and then a constant current (initial luminance is 100c).
d / m ² ), the luminance was measured in the air at regular intervals, and the time required for the luminance to become の of the initial luminance was measured for each sample. Also, the current continues to flow even after the luminance has become 1/2 of the initial luminance, and the luminance is 0 cd.
/ M ² was measured, and this time was taken as the destruction time of the device. The luminance was measured by using an ITO film on which an electron injection layer was provided as an anode, and a counter electrode provided on the ITO film via a hole injection layer and a light emitting layer as a cathode. The current was continuously supplied from the DC power supply, and the luminance was calculated from the value of the output voltage obtained by photoelectrically converting the EL light from the organic EL element by the photodiode. Table 1 shows the measurement results.

[0056]

[Table 1]

As is clear from Table 1, the organic EL devices of Examples 1 and 2 sealed by the method of the present invention are much longer than any of the organic EL devices of Comparative Examples 1 to 3. Life , which is clear even compared to the organic EL device of Reference Example 1.
Crab has a long life.

[0058]

As described above, by practicing the present invention, it is possible to provide an organic EL device having a long lifetime as a device, and accordingly, a long-life organic EL device.
It is also possible to provide an L device.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing a transparent support substrate used in Example 3.

FIG. 2 is a view schematically showing a cross section of the element with a protective layer obtained in Example 3.

FIG. 3 is an end view schematically showing an organic EL element finally obtained in Example 3 and subjected to sealing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Glass plate, 2a, 2b ... ITO film, 3 ... Transparent support substrate, 4 ... Element with a protective layer, 5 ... Hole injection layer, 6
... Light-emitting layer, 7 ... Counter electrode, 8 ... Protective layer, 9 ... Laminated structure, 10 ... Organic EL element that has been subjected to sealing, 11 ... Shield layer, 12, 15 ... Epoxy adhesive, 13 ... Shield glass, 14 ... injection port, 16 ... glass lid.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-267097 (JP, A) JP-A-4-212287 (JP, A) JP-A-60-81797 (JP, A) 157095 (JP, U) Hikaru Hei 3-37991 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) H05B 33/04

Claims (4)

(57) [Claims] 1. An organic EL device having a laminated structure having at least a light-emitting layer made of a fluorescent organic solid interposed between two electrodes facing each other on an outer surface of the laminated structure in an organic EL device. One that continues from the time of forming the light emitting layer
After providing a protective layer made of an electrically insulating polymer compound in a continuous vacuum environment , outside the protective layer, select from a group consisting of an electrically insulating glass, an electrically insulating polymer compound, and an electrically insulating airtight fluid. A method for sealing an organic EL element, comprising providing a single shield layer. 2. The method according to claim 1, wherein the protective layer is formed by physical vapor deposition or chemical vapor deposition.
The method for sealing an organic EL element according to claim 1 , wherein the method is provided by a method. 3. An electrically insulating glass as a material of a siled layer.
Or an electrically insulating polymer film
Made of conductive glass or electrically insulating polymer film
3. The method for sealing an organic EL element according to claim 1 , wherein a moisture absorbing layer is interposed between the shield layer and the organic EL element. 4. An electrically insulating and airtight material as a material of a siled layer.
Shielding layer made of the electrically insulating airtight liquid using a liquid
The method according to claim 1 or 2, wherein a moisture absorbing material is mixed in the inside.
Sealing method of the organic EL element described above.