JP2007103093A - Organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent element of high durability to withstand water and hydrogen. <P>SOLUTION: The organic electroluminescent element has an electrode, an organic compound layer including a light emitting layer, and an inorganic film layer formed on an organic light emitter with a back electrode, on a first substrate where a second substrate is laid on a surface of the inorganic film layer; a gap between a surface of the second substrate facing the inorganic film layer and the inorganic film layer is filled with a resin to form a resin sealing layer; and the periphery top of the first substrate and the second substrate is coated with a sealing adhesive containing a drying agent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic electroluminescent device. In particular, the present invention relates to an organic electroluminescent device having improved storage stability.

  An organic electroluminescent element using a thin film material that emits light when excited by passing an electric current is known. Since organic electroluminescent devices can emit light with high brightness at low voltage, they are widely used in a wide range of fields including mobile phone displays, personal digital assistants (PDAs), computer displays, automobile information displays, TV monitors, or general lighting. It has potential applications and has advantages such as thinning, lightening, miniaturization, and power saving of devices in these fields. For this reason, the expectation as a leading role of the future electronic display market is great. However, in order to be practically used in place of conventional displays in these fields, many technical improvements such as light emission luminance and color tone, durability under wide usage environment conditions, low cost and mass productivity are problems. Yes.

One of the important problems of organic electroluminescence devices is that they are extremely vulnerable to moisture and oxygen. Specifically, the interface between the metal electrode and the organic layer is altered by the influence of moisture, the electrode peels off, Oxidation of the electrode increases the resistance, or the organic material itself is altered by moisture.
As a result, an increase in driving voltage, generation and growth of dark spots (non-light emitting defects), or a decrease in light emission luminance occur, and there is a problem that sufficient reliability cannot be maintained.

In an organic electroluminescent element, sufficient reliability cannot be maintained unless moisture permeation is prevented.
Conventionally, various structures of organic electroluminescent elements for preventing moisture from entering have been proposed. FIG. 2 is a schematic sectional view showing an example of the method, which is a generally known method. The organic electroluminescent element 120 is supported on a glass substrate 110 that does not transmit moisture, and is covered with a glass or metal sealing can 130, and the contact between the sealing can and the glass substrate 110 is covered with an adhesive. Sealing is performed (for example, refer to Patent Document 1). It is also known to fill the internal gas phase with argon gas or nitrogen gas. This structure is characterized by having a gas phase space 140 inside, and moisture or oxygen impervious sealing cans that cause performance degradation due to penetration of moisture and oxygen from the gas phase are moisture from the outside. Intrusion of oxygen and oxygen is prevented, but there is no effect on moisture and oxygen in the existing gas phase space 140. During the assembly of the organic electroluminescent device, it is possible to reduce the moisture and air in the gas phase space by operating in a dehumidified and deaerated environment, but it cannot be completely removed.

  On the other hand, there has also been proposed an attempt to form a sealing layer against moisture by depositing an inorganic material layer on the surface of an organic electroluminescent element on a glass substrate and then depositing an inorganic material layer on the surface (see, for example, Patent Document 2). ). As the inorganic material, silicon nitride, silicon oxynitride, silicon carbide, and amorphous silicon are disclosed. However, the vapor deposition film formed on the organic compound layer has a problem that many defects such as pinholes and cracks are generated. In order to remove these defects, there are means such as increasing the vapor deposition thickness of the inorganic material or forming a multilayer film by repeating the vapor deposition a plurality of times, but this is not preferable in terms of cost and productivity.

Thus, a sealing method that is excellent in moisture barrier properties and also satisfies mass productivity has been desired.
JP 2004-265615 A Japanese Patent No. 3170542

  An object of the present invention is to provide an organic electroluminescent device having improved storage stability, and particularly to provide an organic electroluminescent device having high durability against moisture and oxygen.

The above-described problems of the present invention have been solved by the following means.
<1> An organic electroluminescent element having an inorganic film layer on an organic light emitting part having an electrode, an organic compound layer including at least one light emitting layer on a first substrate, and a back electrode, wherein the second substrate On the surface of the inorganic film layer, filling a gap between the surface of the second substrate facing the inorganic film layer and the inorganic film layer with a resin to form a resin sealing layer, and the first substrate An organic electroluminescent element, wherein the substrate and the peripheral edge of the second substrate are covered with a sealing adhesive containing a desiccant.
<2> The organic electroluminescent element according to <1>, wherein the desiccant contains at least one selected from barium oxide, calcium oxide, and strontium oxide.
<3> The organic electric field according to <1> or <2>, wherein the sealing adhesive contains the desiccant in an amount of 0.01% by mass to 20% by mass with respect to the sealing adhesive. Light emitting element.
<4> The inorganic film layer contains at least one selected from silicon nitride, silicon oxynitride, silicon oxide, and silicon carbide, according to any one of <1> to <3> Organic electroluminescent element.
<5> The organic electroluminescent element according to any one of <1> to <4>, wherein the first substrate and the second substrate are both glass.

  According to the present invention, an organic electroluminescence device having high durability against moisture and oxygen is provided.

The organic electroluminescent element structure of the present invention is an integral structure in which a light emitting element is sandwiched between two substrates, and in order, a first substrate, an electrode, an organic compound layer including a light emitting layer, and a back surface. A light-emitting portion composed of an electrode and a second substrate are laminated, and an inorganic film layer is further provided on the side of the back electrode facing the second substrate, and the inorganic film layer and the second substrate And a resin sealing layer filling the gap. In addition, peripheral edges of the two substrates are covered with a sealing adhesive.
Hereinafter, 1) an organic electroluminescent element having an organic compound layer including a substrate, an electrode, and a light emitting layer, 2) an inorganic film layer, 3) a resin sealing layer, and 4) a sealing adhesive will be described.

1. Organic electroluminescent device The organic electroluminescent device according to the present invention includes conventionally known organic compound layers such as a hole transport layer, an electron transport layer, a block layer, an electron injection layer, and a hole injection layer in addition to the light emitting layer. You may have.

Details will be described below.
1) Layer structure <Electrode>
At least one of the pair of electrodes of the organic electroluminescent element of the present invention is a transparent electrode, and the other is a back electrode. The back electrode may be transparent or non-transparent.
<Configuration of organic compound layer>
There is no restriction | limiting in particular as a layer structure of the said organic compound layer, Although it can select suitably according to the use and objective of an organic electroluminescent element, It is formed on the said transparent electrode or the said back electrode. preferable. In this case, the organic compound layer is formed on the front surface or one surface on the transparent electrode or the back electrode.
There is no restriction | limiting in particular about the shape of a organic compound layer, a magnitude | size, thickness, etc., According to the objective, it can select suitably.

Specific examples of the layer configuration include the following, but the present invention is not limited to these configurations.
Anode / hole transport layer / light emitting layer / electron transport layer / cathode,
Anode / hole transport layer / light emitting layer / block layer / electron transport layer / cathode,
Anode / hole transport layer / light emitting layer / block layer / electron transport layer / electron injection layer / cathode,
Anode / hole injection layer / hole transport layer / light emitting layer / block layer / electron transport layer / cathode,
Anode / hole injection layer / hole transport layer / light emitting layer / block layer / electron transport layer / electron injection layer / cathode.

Each layer will be described in detail below.
2) Hole transport layer The hole transport layer used in the present invention contains a hole transport material. The hole transport material is not particularly limited as long as it has either a function of transporting holes or a function of blocking electrons injected from the cathode. As the hole transport material used in the present invention, any of a low molecular hole transport material and a polymer hole transport material can be used.
Specific examples of the hole transport material used in the present invention include the following materials.

Carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazol derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, Styryl anthracene derivative, fluorenone derivative, hydrazone derivative, stilbene derivative, silazane derivative, aromatic tertiary amine compound, styrylamine compound, aromatic dimethylidene compound, porphyrin compound, polysilane compound, poly (N-vinylcarbazole) derivative , Aniline copolymer, thiophene oligomer, conductive polymer oligomer such as polythiophene, polythiophene derivative, polyphenylene derivative, polyphenylene vinylene derivative, polyfluorene Polymeric compounds such as derivatives.
These may be used alone or in combination of two or more.

  The thickness of the hole transport layer is preferably 10 nm to 200 nm, and more preferably 20 nm to 80 nm. If the thickness exceeds 200 nm, the driving voltage may increase. If the thickness is less than 10 nm, the light emitting element may be short-circuited, which is not preferable.

3) Hole injection layer In the present invention, a hole injection layer can be provided between the hole transport layer and the anode.
The hole injection layer is a layer that facilitates injection of holes from the anode into the hole transport layer, and specifically, a material having a small ionization potential is preferably used among the hole transport materials. For example, a phthalocyanine compound, a porphyrin compound, a starburst type triarylamine compound, etc. can be mentioned, It can use suitably.
The thickness of the hole injection layer is preferably 1 nm to 30 nm.

4) Light emitting layer The light emitting layer used in the present invention contains at least one kind of light emitting material, and may contain a hole transport material, an electron transport material, and a host material as necessary.
The light emitting material used in the present invention is not particularly limited, and either a fluorescent light emitting material or a phosphorescent light emitting material can be used. A phosphorescent material is preferred from the viewpoint of luminous efficiency.

  Examples of fluorescent light-emitting materials include benzoxazole derivatives, benzimidazole derivatives, benzothiazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives, perylene derivatives, perinone derivatives, oxalates. Diazole derivatives, aldazine derivatives, pyralidine derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, styrylamine derivatives, aromatic dimethylidene compounds, 8-quinolinol derivative metal complexes and rare earths Various metal complexes represented by complexes, polythiophene derivatives, polyphenylene derivatives, polyphenylene vinylene derivatives, polyfluor Polymeric compounds such as polyalkylene derivatives. These can be used alone or in combination of two or more.

  Although it does not specifically limit as a phosphorescence-emitting material, An ortho metalated metal complex or a porphyrin metal complex is preferable.

  The ortho-metalated metal complex includes, for example, Akio Yamamoto, “Organic Metal Chemistry: Fundamentals and Applications”, pages 150 to 232; Yersin's “Photochemistry and Photophysics of Coordination Compounds”, pages 71-77, pages 135-146, Springer-Verlag (published in 1987), etc. The use of the orthometalated metal complex as a light emitting material in the light emitting layer is advantageous in terms of high luminance and excellent light emission efficiency.

  There are various ligands that form the ortho-metalated metal complex, which are also described in the above documents. Among them, preferred ligands include 2-phenylpyridine derivatives, 7,8- Examples include benzoquinoline derivatives, 2- (2-thienyl) pyridine derivatives, 2- (1-naphthyl) pyridine derivatives, and 2-phenylquinoline derivatives. These derivatives may have a substituent if necessary. The orthometalated metal complex may have other ligands in addition to the above ligands.

The orthometalated metal complex used in the present invention can be obtained from Inorg Chem. 1991, 30, 1685, 1988, 27, 3464, 1994, 33, 545, Inorg. Chim. Acta, 1991, No. 181, page 245; Organomet. Chem. 1987, No. 335, 293, J. Am. Am. Chem. Soc. It can be synthesized by various known techniques such as 1985, No. 107, page 1431.
Among the ortho-metalated complexes, compounds emitting light from triplet excitons can be suitably used in the present invention from the viewpoint of improving luminous efficiency.

Of the porphyrin metal complexes, a porphyrin platinum complex is preferred.
A phosphorescent material may be used alone or in combination of two or more. Further, a fluorescent material and a phosphorescent material may be used at the same time.

  The host material is a material having a function of causing energy transfer from the excited state to the fluorescent light-emitting material or the phosphorescent light-emitting material, and as a result, causing the fluorescent light-emitting material or the phosphorescent light-emitting material to emit light.

The host material is not particularly limited as long as it is a compound capable of transferring exciton energy to the light emitting material, and can be appropriately selected according to the purpose. Specifically, a carbazole derivative, a triazole derivative, an oxazole derivative, Oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic Tertiary amine compounds, styrylamine compounds, aromatic dimethylidene compounds, porphyrin compounds, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopi Dioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, heterocyclic tetracarboxylic anhydrides such as naphthaleneperylene, phthalocyanine derivatives, metal complexes of 8-quinolinol derivatives, metal phthalocyanines, benzoxazoles and benzothiazoles Various metal complexes represented by metal complexes as ligands, polysilane compounds, poly (N-vinylcarbazole) derivatives, aniline copolymers, thiophene oligomers, conductive polymer oligomers such as polythiophene, polythiophene derivatives, polyphenylene derivatives And polymer compounds such as polyphenylene vinylene derivatives and polyfluorene derivatives. These compounds may be used individually by 1 type, and may use 2 or more types together.
As content in the light emitting layer of a host material, 0 mass%-99.9 mass% are preferable, More preferably, they are 0 mass%-99.0 mass%.

5) Block layer In this invention, a block layer can be provided between a light emitting layer and an electron carrying layer. The block layer is a layer that suppresses the diffusion of excitons generated in the light emitting layer, and also a layer that suppresses holes from penetrating to the cathode side.

  The material used for the block layer is not particularly limited as long as it is a material that can receive electrons from the electron transport layer and pass the electrons to the light emitting layer, and a general electron transport material can be used. For example, the following materials can be mentioned. Triazole derivatives, oxazole derivatives, oxadiazol derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyrandioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives , Metal complexes of heterocyclic tetracarboxylic anhydrides such as naphthaleneperylene, phthalocyanine derivatives, 8-quinolinol derivatives and metal complexes having metal phthalocyanine, benzoxazole and benzothiazol as ligands Polymers such as complexes, aniline copolymers, conductive polymer oligomers such as thiophene oligomers and polythiophenes, polythiophene derivatives, polyphenylene derivatives, polyphenylene vinylene derivatives, polyfluorene derivatives, etc. It can be mentioned. These may be used individually by 1 type and may use 2 or more types together.

6) Electron transport layer In the present invention, an electron transport layer containing an electron transport material can be provided.
The electron transport material is not limited as long as it has either a function of transporting electrons or a function of blocking holes injected from the anode, and is mentioned when explaining the block layer. A suitable electron transport material can be used.
The thickness of the electron transport layer is preferably 10 nm to 200 nm, and more preferably 20 nm to 80 nm.

  If the thickness exceeds 200 nm, the driving voltage may increase, and if it is less than 10 nm, the light emitting device may be short-circuited.

7) Electron Injection Layer In the present invention, an electron injection layer can be provided between the electron transport layer and the cathode.
The electron injection layer is a layer that facilitates injection of electrons from the cathode into the electron transport layer. Specifically, lithium salts such as lithium fluoride, lithium chloride, and lithium bromide, sodium fluoride, sodium chloride, fluoride An alkali metal salt such as cesium, an insulating metal oxide such as lithium oxide, aluminum oxide, indium oxide, and magnesium oxide can be preferably used.
The thickness of the electron injection layer is preferably 0.1 to 5 nm.

8) Formation method of organic compound layer The organic compound layer is formed by a dry film forming method such as vapor deposition or sputtering, dipping, spin coating, dip coating, casting, die coating, or roll coating. The film can be suitably formed by any of wet film forming methods such as a coating method, a bar coating method, and a gravure coating method.
Of these, the dry method is preferred from the viewpoint of luminous efficiency and durability.

Next, the substrate and electrodes used in the organic electroluminescence device of the present invention will be described.
9) Substrate As the material of the substrate used in the present invention, both the first substrate and the second substrate are preferably materials that do not transmit moisture or materials with extremely low moisture permeability, and light emitted from the organic compound layer. A material that does not scatter or attenuate the light is preferable. Specific examples include, for example, YSZ (zirconia stabilized yttrium), inorganic materials such as glass, polyethylene terephthalate, polybutylene terephthalate, polyester such as polyethylene naphthalate, polystyrene, polycarbonate, Examples thereof include organic materials such as polyethersulfone, polyarylate, allyl diglycol carbonate, polyimide, polycycloolefin, norbornene resin, and synthetic resin such as poly (chlorotrifluoroethylene).
In the case of the organic material, it is preferable that the organic material is excellent in heat resistance, dimensional stability, solvent resistance, electrical insulation, workability, low air permeability, low moisture absorption, and the like. Among these, when the material of the transparent electrode is indium tin oxide (ITO) suitably used as the material of the transparent electrode, a material having a small difference in lattice constant from the indium tin oxide (ITO) is used. preferable. These materials may be used alone or in combination of two or more.

  There is no restriction | limiting in particular about the shape of a board | substrate, a structure, a magnitude | size, It can select suitably according to the use, purpose, etc. of a light emitting element. Generally, the shape is a plate shape. The structure may be a single layer structure, a laminated structure, may be formed of a single member, or may be formed of two or more members.

  The substrate may be colorless and transparent, or may be colored and transparent, but is preferably colorless and transparent in that it does not scatter or attenuate light emitted from the light emitting layer.

The substrate is preferably provided with a moisture permeation preventing layer (gas barrier layer) on the front surface or the back surface (on the transparent electrode side). As the material for the moisture permeation preventive layer (gas barrier layer), inorganic materials such as silicon nitride and silicon oxide are preferably used. The moisture permeation preventing layer (gas barrier layer) can be formed by, for example, a high frequency sputtering method.
The substrate may be further provided with a hard coat layer, an undercoat layer, and the like as required.

10) Anode As the anode used in the present invention, it is usually sufficient to have a function as an anode for supplying holes to the organic compound layer, and the shape, structure, size and the like are not particularly limited. Depending on the use and purpose of the light-emitting element, it can be appropriately selected from known electrodes.

  As a material for the anode, for example, a metal, an alloy, a metal oxide, an organic conductive compound, or a mixture thereof can be preferably cited. A material having a work function of 4.0 eV or more is preferable. Specific examples include semiconductive metals such as tin oxide doped with antimony and fluorine (ATO, FTO), tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and zinc indium oxide (IZO). Metals such as oxides, gold, silver, chromium and nickel, and mixtures or laminates of these metals and conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, polyaniline, polythiophene, polypyrrole Organic conductive materials such as copper, and laminates of these with ITO.

  The anode is, for example, a printing method, a wet method such as a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, or a chemical method such as a CVD or a plasma CVD method. Can be formed on the substrate in accordance with a method appropriately selected in consideration of suitability. For example, when ITO is selected as the anode material, the anode can be formed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like. Moreover, when selecting an organic electroconductive compound as a material of an anode, it can carry out according to the wet film forming method.

  There is no restriction | limiting in particular as a formation position in the said light emitting element of an anode, Although it can select suitably according to the use and objective of this light emitting element, It is preferable to form on the said board | substrate. In this case, the anode may be formed on the entire one surface of the substrate or a part thereof.

  The patterning of the anode may be performed by chemical etching such as photolithography, or may be performed by physical etching using a laser or the like, or may be performed by vacuum deposition or sputtering by overlapping a mask. Etc., or may be performed by a lift-off method or a printing method.

The thickness of the anode can be appropriately selected depending on the material and cannot be generally defined, but is usually 10 nm to 50 μm, and preferably 50 nm to 20 μm.
The resistance value of the anode is preferably 10 ³ Ω / □ or less, and more preferably 10 ² Ω / □ or less.
The anode may be colorless and transparent or colored and transparent. In order to extract light emitted from the anode side, the transmittance is preferably 60% or more, and more preferably 70% or more. This transmittance can be measured according to a known method using a spectrophotometer.

  The anode is described in detail in the book “New Development of Transparent Electrode Film”, published by CMC (1999), supervised by Yutaka Sawada, and these can be applied to the present invention. When using a plastic substrate having low heat resistance, an anode formed using ITO or IZO at a low temperature of 150 ° C. or lower is preferable.

11) Cathode As a cathode that can be used in the present invention, it suffices as long as it normally has a function as a cathode for injecting electrons into the organic compound layer, and the shape, structure, size and the like are not particularly limited. However, it can be appropriately selected from known electrodes according to the use and purpose of the light-emitting element.

  Examples of the material for the cathode include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof, and those having a work function of 4.5 eV or less are preferable. Specific examples include alkali metals (eg, Li, Na, K, Cs, etc.), alkaline earth metals (eg, Mg, Ca, etc.), gold, silver, lead, aluminum, sodium-potassium alloys, lithium-aluminum alloys, magnesium. -Rare earth metals such as silver alloys, indium, ytterbium, and the like. These may be used alone, but from the viewpoint of achieving both stability and electron injection properties, two or more of them can be suitably used in combination.

  Among these, alkali metals and alkalinity metals are preferable from the viewpoint of electron injection properties, and materials mainly composed of aluminum are preferable from the viewpoint of excellent storage stability. The material mainly composed of aluminum is aluminum alone, or an alloy or mixture of aluminum and 0.01% by mass to 10% by mass of alkali metal or alkaline earth metal (for example, lithium-aluminum alloy, magnesium-aluminum alloy, etc. ).

  The cathode materials are described in detail in JP-A-2-15595 and JP-A-5-121172, and these can be applied to the present invention.

  There is no restriction | limiting in particular in the formation method of a cathode, It can carry out according to a well-known method. For example, a printing method, a wet method such as a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, a chemical method such as a CVD method or a plasma CVD method, etc. It can be formed on the substrate according to a method appropriately selected in consideration of suitability. For example, when a metal or the like is selected as the material of the cathode, one or more of them can be simultaneously or sequentially performed according to a sputtering method or the like.

  The patterning of the cathode may be performed by chemical etching such as photolithography, or may be performed by physical etching using a laser or the like, or vacuum deposition or sputtering is performed with a mask overlapped. It may be performed by a lift-off method or a printing method.

There is no restriction | limiting in particular as a formation position in the organic electroluminescent element of a cathode, Although it can select suitably according to the use and objective of this light emitting element, forming in an organic compound layer is preferable. In this case, the cathode may be formed on the entire organic compound layer or a part thereof.
Further, a dielectric layer made of the alkali metal or the alkaline earth metal fluoride may be inserted between the cathode and the organic compound layer with a thickness of 0.1 to 5 nm.
The dielectric layer can be formed by, for example, a vacuum deposition method, a sputtering method, an ion plating method, or the like.

The thickness of the cathode can be appropriately selected depending on the material and cannot be generally defined, but is usually 10 nm to 5 μm, and preferably 50 nm to 1 μm.
The cathode may be transparent or opaque. The transparent cathode can be formed by thinly forming the cathode material to a thickness of 1 to 10 nm and further laminating the transparent conductive material such as ITO or IZO.

2. Inorganic Film Layer The inorganic film layer used in the present invention is an insulating layer provided on the back electrode and is a layer that prevents the light emitting element from being deteriorated by the intrusion of gas such as moisture or oxygen.
As the material for the inorganic film layer used in the present invention, silicon nitride, silicon oxynitride, silicon oxide, and silicon carbide are preferably used.
The inorganic film layer used in the present invention can be formed by a CVD method, an ion plating method, a sputtering method or a vapor deposition method.
The thickness of the inorganic film layer used in the present invention is preferably 0.01 μm to 10 μm. If it is thinner than 0.01 μm, the insulating function and the moisture and gas preventing function are insufficient, which is not preferable. On the other hand, if it is thicker than 10 μm, it takes a long time to form a film, which is not preferable in the process. In addition, the film stress may increase, causing film peeling and the like. A thicker film can be obtained by repeating the film formation a plurality of times.

3. Resin Sealing Layer The resin sealing layer used in the present invention is a layer that fills the gas phase space between the inorganic film layer and the second substrate. Accordingly, the present invention is characterized in that the gap between the inorganic film layer and the second substrate is entirely filled with resin and does not have a gas phase space.
<Material>
The resin material of the resin sealing layer is not particularly limited, and acrylic resin, epoxy resin, fluorine resin, silicon resin, rubber resin, ester resin, etc. can be used. An epoxy resin is preferable from the viewpoint of function. Among the epoxy resins, a thermosetting epoxy resin or a photocurable epoxy resin is preferable.
<Production method>
The method for producing the resin sealing layer is not particularly limited, and examples thereof include a method of applying a resin solution, a method of pressure bonding or thermocompression bonding of a resin sheet, and a method of dry polymerization by vapor deposition or sputtering.
<Film thickness>
The thickness of the resin sealing layer is preferably 1 μm or more and 1 mm or less. More preferably, they are 5 micrometers or more and 100 micrometers or less, Most preferably, they are 10 micrometers or more and 50 micrometers or less. If it is thinner than this, the inorganic film may be damaged when the second substrate is mounted. On the other hand, if the thickness is larger than this, the thickness of the electroluminescent element itself is increased, and the thin film property that is characteristic of the organic electroluminescent element is impaired.

4). Sealing adhesive The organic electroluminescent element in the present invention is sandwiched between two substrates, and the peripheral edge of the substrate is sealed with a sealing adhesive containing a desiccant.
The sealing adhesive in the present invention has a function of preventing intrusion of moisture and oxygen from the end portion.
The organic electroluminescent device of the present invention is sandwiched between two substrates impermeable to moisture and gas, and has no gas phase space inside, so that intrusion of gas such as moisture and oxygen from the outside Is kept very low, but it can be made more perfect by further sealing the edge with a sealing adhesive containing a desiccant.

<Material>
As the material of the sealing adhesive, the same material as that used for the resin sealing layer can be used. Among these, epoxy adhesives are preferable from the viewpoint of moisture prevention, and among them, thermosetting epoxy adhesives and photocurable epoxy adhesives are preferable.

It is also preferable to add a filler to the above material.
The filler added to the sealant is preferably an inorganic material such as SiO ₂ , SiO (silicon oxide), SiON (silicon oxynitride) or SiN (silicon nitride). Addition of the filler increases the viscosity of the sealant, improves processing suitability, and improves moisture resistance.

<Drying agent>
-Kind The desiccant used in the present invention is preferably barium oxide, calcium oxide, or strontium oxide.
-Addition amount The addition amount of the desiccant with respect to the sealing adhesive is preferably 0.01% by mass or more and 20% by mass or less, and more preferably 0.05% by mass or more and 15% by mass or less. If the amount is less than this, the effect of adding the desiccant is diminished. On the other hand, when it is more than this, it becomes difficult to uniformly disperse the desiccant in the sealing adhesive, which is not preferable.
<Prescription of sealing adhesive>
・ Polymer composition, concentration,
It does not specifically limit as a sealing adhesive agent, The said thing can be used. For example, XNR5516 manufactured by Nagase Chemtech Co., Ltd. can be cited as a photo-curable epoxy adhesive. What is necessary is just to add and disperse | distribute the said desiccant directly there.
-Thickness The coating thickness of the sealing adhesive is preferably 1 μm or more and 1 mm or less. If it is thinner than this, the sealing adhesive cannot be applied uniformly, which is not preferable. On the other hand, if it is thicker than this, the route through which moisture invades becomes wide, which is not preferable.
<Sealing method>
In the present invention, the electroluminescent device of the present invention can be obtained by applying an arbitrary amount of the sealing adhesive containing the desiccant with a dispenser and the like, overlaying the substrate 2 after application, drying and curing. .

5. Embodiment of Organic Light-Emitting Element Structure Next, an embodiment of the organic light-emitting element structure will be specifically described.
FIG. 1 is a schematic cross-sectional view of an organic light emitting device structure according to the present invention. The organic light emitting element structure 10 has an organic compound layer including an electrode and an organic light emitting layer on the first substrate 11. Specifically, it has a laminated structure such as an electrode (anode), a hole injection layer, a hole transport layer, a light emitting layer, a block layer, an electron transport layer, an electron injection layer, and a back electrode (cathode). An inorganic film layer 30 is provided on the back electrode. Furthermore, the sealing layer 40 is formed by filling the gap between the inorganic film layer 30 and the second substrate 12 with resin. Thereafter, the sealing adhesives 50a and 50b are filled in the cross-sections at the peripheral edges of the two substrates. Next, the electroluminescent element of the present invention can be obtained by overlaying the second substrate and photocuring and / or thermosetting.

  Therefore, in the obtained structure 10, the organic light emitting element 20 including the light emitting layer is completely removed from the internal air layer by the block of ingress of gas such as moisture and oxygen by the inorganic layer 30 and the resin sealing layer 40. Intrusion of gas such as moisture and oxygen from the plane of the organic light emitting device is highly suppressed. Furthermore, since the sealing adhesives 50a and 50b containing the desiccant at the end portion prevent the intrusion of gas such as moisture and oxygen from the end portion, comprehensively against the invasion of gas such as moisture and oxygen. Highly protected.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the examples described below.

First, the organic electroluminescent elements used in the examples of the present invention will be described.
<Production of organic electric field element>
A glass plate having a thickness of 0.5 mm and a square of 2.5 cm was used as a substrate. This substrate was introduced into a vacuum chamber, and an ITO target (indium: tin = 95: 5 (moles) with a SnO ₂ content of 10% by mass. Ratio)), an ITO thin film (thickness 0.2 μm) was formed on the substrate as a transparent electrode by DC magnetron sputtering (conditions: substrate temperature 250 ° C., oxygen pressure 1 × 10 ⁻³ Pa). The surface resistance of the ITO thin film was 10Ω / □.
Next, the substrate on which the transparent electrode was formed was put into a cleaning container and subjected to IPA cleaning, and then UV-ozone treatment was performed for 30 minutes.
On this transparent electrode, copper phthalocyanine was deposited as a hole injection layer by a vacuum deposition method at a rate of 1 nm / second to provide 0.01 μm.

  Next, a hole transport layer was provided thereon. As a hole transport material, N, N′-dinaphthyl-N, N′-diphenylbenzidine (NPD) was deposited by a vacuum deposition method to provide a 0.3 μm hole transport layer.

On top of this, a phosphorescent material, tris (2-phenylpyridyl) iridium complex (Ir (ppy) ₃ ), and 4,4′-N, N′-dicarbazolebiphenyl (CBP) as a host compound were deposited at a deposition ratio of 5 / 100 was co-evaporated by a vacuum deposition method to provide a 0.03 μm light emitting layer.
A block layer was provided thereon. As the electron transport material used for the block layer, aluminum (III) bis (2-methyl-8-quinolinato) 4-phenylphenolate (Balq ₂ ) is used, and is deposited by vacuum deposition at a rate of 1 nm / second. A .01 μm block layer was provided.
Further thereon, tris (8-hydroxyquinolinato) aluminum (Alq ₃ ) was used as an electron transport material, and a 0.04 μm electron transport layer was provided by vacuum deposition at a rate of 1 nm / second.

Furthermore, LiF was vapor-deposited as an electron injection layer at a rate of 1 nm / second to provide a 0.002 μm electron injection layer.
Further, a patterned mask (a mask with a light emission area of 2 mm × 2 mm) was placed on the electron injection layer, and aluminum was deposited by 0.25 μm in a vapor deposition apparatus to form a back electrode.
Aluminum lead wires were respectively connected from the transparent electrode (functioning as an anode) and the back electrode to form a light emitting laminate.

Example 1
1) Inorganic film layer The following inorganic film layer was provided on the back electrode of the light emitting laminate.
An inorganic film 5 μm of SiN (1 μm) / SiON (3 μm) / SiN (1 μm) was formed at a film forming rate of 200 nm / min using a CVD film forming apparatus manufactured by ULVAC.

2) Resin sealing layer Thermosetting epoxy resin TB3124 manufactured by ThreeBond Co., Ltd. was applied onto the sealing layer with a dispenser and heated at 100 ° C. for 1 hour to be temporarily cured.
3) Sealing adhesive layer The sealing adhesive was prepared as follows. 1 g of calcium oxide powder was put into 100 g of XNR5516HV (adhesive A) manufactured by Nagase Chemtech Co., Ltd. and kneaded in a ball mill for 8 hours to obtain a sealing adhesive containing a desiccant containing 1% by mass of calcium oxide.
The desiccant-containing sealing adhesive was applied to the peripheral edge of the first substrate on which the light emitting laminate was not provided with a dispenser. On top of this, glass as a second substrate was stacked and adhered by a vacuum laminator. After adhesion, the sealing adhesive layer was irradiated with a mercury lamp and photocured. Then, it heated at 100 degreeC for 3 hours in a vacuum oven, the resin sealing layer and the sealing contact bonding layer were fully hardened, and the electroluminescent element of this invention was obtained.

Examples 2-4
The desiccant of the sealing adhesive layer of Example 1 was changed as shown in Table 1 to prepare.

Production of Comparative Sample A A sample in which the desiccant of the sealing adhesive layer of Example 1 was removed was produced.

Preparation of Comparative Sample B A sample excluding the sealing adhesive layer of Example 1 was prepared.

Production of Comparative Sample C <Production of Sample in Form of FIG. 2>
In the same manner as in Example 1, a light emitting laminate was provided on a glass substrate. The light-emitting laminate obtained here was put in a glove box substituted with nitrogen gas having an oxygen gas concentration of 80 ppm and a dew point of −80 ° C., and a stainless steel sealing cap was used at the position 150 in FIG. Sealed with the desiccant-containing sealing adhesive prepared in Example 1 as the sealing adhesive

<Performance evaluation>
The produced organic electroluminescent element was evaluated by the following method.
Using a source measure unit type 2400 manufactured by Toyo Technica, direct voltage was applied to the electroluminescent element to emit light, and the initial light emitting performance was measured. Table 2 shows the luminous efficiency at 2000 Cd / m ² and the voltage (V) at that time. Moreover, the dark spot at the time of light emission and light emission area degeneration were observed using Nikon optical microscope ME600.
Furthermore, the electroluminescent device was put in a constant temperature and humidity oven of 60 ° C. and 90% RH, and after 500 hours elapsed, the luminous efficiency at 2000 Cd / m ² and the voltage (V), dark spot, and light emitting area at that time were reduced. Observed and shown in Table 2.

  From this result, it can be seen that the electroluminescent device of the present invention has excellent storage characteristics because no dark spots are generated even when stored at high temperature and high humidity, and the degeneration of the light emitting area is small.

It is a schematic sectional drawing of the organic electroluminescent element structure which concerns on embodiment of this invention. It is a schematic sectional drawing of the organic electroluminescent element structure which concerns on comparative embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 100: Organic electroluminescent element structure 11, 110: 1st board | substrate 20, 120: Organic electroluminescent element laminated body 30: Inorganic layer 40: Resin sealing layer 12: 2nd board | substrate 50a, 50b, 150a, 150b: Sealing adhesive layer 130: Sealing can

Claims (5)

  An organic electroluminescence device having an electrode, an organic compound layer including at least one light-emitting layer on an first substrate, and an inorganic film layer on an organic light-emitting portion having a back electrode, wherein the second substrate is the inorganic substrate A resin sealing layer is formed by filling a gap between the surface of the second substrate facing the inorganic film layer and the surface of the inorganic film layer with a resin to form a resin sealing layer. An organic electroluminescent element, wherein a peripheral edge of the second substrate is covered with a sealing adhesive containing a desiccant.   The organic electroluminescent device according to claim 1, wherein the desiccant contains at least one selected from barium oxide, calcium oxide, and strontium oxide.   The organic electroluminescent element according to claim 1, wherein the sealing adhesive contains the drying agent in an amount of 0.01% by mass to 20% by mass with respect to the sealing adhesive.   The organic electric field according to any one of claims 1 to 3, wherein the inorganic film layer contains at least one selected from silicon nitride, silicon oxynitride, silicon oxide, and silicon carbide. Light emitting element.   The organic electroluminescent element according to any one of claims 1 to 4, wherein both the first substrate and the second substrate are made of glass.

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