JPH09129376A - Organic EL element - Google Patents

Abstract

(57) Abstract: A conventional organic EL device using a transparent resin substrate as a transparent substrate has uneven brightness and low light emission stability. A transparent thermosetting resin substrate having a flat surface is used as a transparent resin substrate, and a crystalline transparent conductive film having a grain size of 500 angstroms or less or an amorphous material is formed on the flat surface of the transparent thermosetting resin substrate. A transparent electrode made of a transparent conductive film is formed via a moisture-proof inorganic oxide film,
An opposing electrode is formed on the transparent electrode via an organic single layer portion or an organic multilayer portion containing an organic light emitting material to obtain an organic EL element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to organic electroluminescence (hereinafter referred to as "electroluminescence"
L ". ) Device, and more particularly, to an organic EL device using a transparent resin substrate.

[0002]

2. Description of the Related Art EL elements are self-luminous and thus have high visibility, and since they are completely solid elements, they have excellent impact resistance. It has been attempted to be used as a surface light source. EL elements are roughly classified into inorganic EL elements and organic EL elements.
The device not only has the advantage that the driving voltage can be significantly reduced as compared with the inorganic EL device,
It has the feature that it is possible to make full color including blue.

An organic EL device having the above characteristics usually has a structure in which a transparent electrode, an organic single layer part or an organic multilayer part containing an organic light emitting material, and a counter electrode are sequentially laminated on a transparent substrate, As a transparent electrode, a crystalline indium tin oxide film (hereinafter referred to as “crystalline ITO film”) has been frequently used because of its high transparency and high conductivity. In an organic EL element using a transparent electrode made of a crystalline substance (hereinafter referred to as “crystalline transparent electrode”), the size (grain size) of fine crystal grains on the surface of the crystalline transparent electrode causes uneven brightness of the element and It is known that the emission stability is greatly affected, and by setting the grain size to 500 angstroms or less, it is possible to obtain an organic EL element having high luminance stability without uneven brightness (Japanese Patent Laid-Open No. 6-76950). See the bulletin).

By the way, a glass substrate has been used as a transparent substrate for an organic EL element, but a transparent resin substrate is used as the transparent substrate in order to reduce the weight of the organic EL element and further improve impact resistance. Is being considered.
As the transparent resin substrate, it has been attempted to use a substrate made of a thermoplastic resin such as polymethylmethacrylate, polystyrene, or polyethylene terephthalate (see Japanese Patent Laid-Open No. 251429/1990).

[0005]

However, the organic E
When the above-mentioned thermoplastic resin substrate is used as the transparent substrate of the L element, there is no unevenness in brightness and an organic EL element having high light emission stability cannot be obtained.

It is an object of the present invention to provide an organic EL element which is free from uneven brightness and has high light emission stability even though a transparent resin substrate is used as the transparent substrate. .

[0007]

Means for Solving the Problems The inventors of the present invention have made extensive studies as to the reason why an organic EL element having high luminance stability without uneven brightness when a thermoplastic resin substrate is used cannot be obtained. 1) The flatness of the surface of the thermoplastic resin substrate is low in the first place, and therefore the flatness of the surface of the transparent electrode formed on the thermoplastic resin substrate is also impaired, (2) the thermoplastic resin on the thermoplastic resin substrate, It is difficult to form a crystalline transparent conductive film having a grain size of 500 angstroms or less under the substrate temperature condition in which the substrate does not undergo thermal deformation. (3) The crystalline transparent conductive film having a grain size of 500 angstroms or less has a grain size of By once forming a crystalline transparent conductive film having a thickness of more than 500 angstroms, and then subjecting the crystalline transparent conductive film to UV ozone irradiation or ion irradiation. Can be obtained (JP-A-6
-76950), a crystalline transparent conductive film having a grain size of more than 500 angstroms is formed on a thermoplastic resin substrate, and then UV ozone irradiation or ion irradiation is performed to make the crystalline transparent conductive film have a grain size of 500.
It has been found that when the thickness is set to angstrom, the thermoplastic resin substrate is damaged by UV ozone irradiation or ion irradiation, so that it is not possible to obtain an organic EL element having no uneven brightness and high light emission stability.

The present invention has been made on the basis of such knowledge, and the organic EL of the present invention which achieves the above objects.
The element comprises a transparent resin substrate, a transparent electrode formed on the transparent resin substrate via a moisture-proof inorganic oxide film, and an organic single layer portion or an organic multilayer portion containing an organic light emitting material on the transparent electrode. And a counter electrode formed on, the transparent resin substrate is a transparent thermosetting resin substrate having a flat surface,
The moisture-proof inorganic oxide film is formed on the flat surface of the transparent thermosetting resin substrate, and the transparent electrode is a crystalline transparent conductive film or an amorphous transparent conductive film having a grain size of 500 angstroms or less. It is characterized by that.

[0009]

Embodiments of the present invention will be described below in detail. As described above, the organic EL device of the present invention includes a transparent resin substrate, a transparent electrode formed on the transparent resin substrate via a moisture-proof inorganic oxide film, and an organic single layer portion containing an organic light emitting material or The transparent resin substrate has a counter electrode formed on the transparent electrode via an organic multilayer portion, and the transparent resin substrate is a transparent thermosetting resin substrate having a flat surface.

Here, the "flat surface" in the present invention of the transparent thermosetting resin substrate has such a flatness that it is possible to obtain an organic EL element having high luminance stability without uneven brightness. The flatness required for the “flat surface” depends on the material and forming method of the moisture-proof inorganic oxide film, the material and forming method of the transparent electrode, and the like. For example, in the case of forming a moisture-proof inorganic oxide film and a transparent electrode of the material described later by a physical vapor deposition method, the "flat surface"
Is preferably a surface having a root-mean-square value of surface roughness of 300 angstroms or less and 20 or less projections of 600 angstroms or more existing in a 500 μm square area on the flat surface. The "root mean square value of the surface roughness" in the present invention for the above flat surface is the mean square value of the deviation from the mean value of the height of the unevenness of the surface, and the size of the unevenness of the surface. Means degree. Further, in the present invention, “500 μm on a flat surface”
The number of projections of 600 angstroms or more existing in the corner area "means the average of the number of projections of 600 angstroms or more present in each of the 500 μm square areas arbitrarily set on the flat surface. Means a value. The height and the number of protrusions in each region can be obtained by using an electron microscope, an atomic force microscope, or the like.

It is desirable that the transparent thermosetting resin substrate having a flat surface has a transmittance of light having a wavelength of 400 to 700 nm of 70% or more, preferably 90% or more. As such a transparent thermosetting resin substrate, from the viewpoint of transparency and moldability, a transparent polyolefin thermosetting resin is preferable, and it contains a polyfunctional monomer having two or more unsaturated groups. A polyolefin-based copolymer obtained by polymerizing the above composition is more preferably used.

Specific examples of the above polyfunctional monomer having two or more unsaturated groups include (i) ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate and triethylene glycol di (meth) acrylate. , Glycerol di (meth) acrylate, glycerol tri (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, penta Di-, tri-, polyhydric alcohols such as erythritol tetra (meth) acrylate,
Tetra- (meth) acrylates, (ii) aromatic polyfunctional monomers such as p-divinylbenzene, o-divinylbenzene, (iii) (meth) acrylic acid vinyl ester, (meth) acrylic acid allyl ester, etc. Esters, (iv) dienes such as butadiene, hexadiene, pentadiene,
Examples thereof include (v) a monomer having a phosphazene skeleton in which a polymerized polyfunctional group is introduced from dichlorophosphazene as a raw material, and (vi) a polyfunctional monomer having a heteroatom cyclic skeleton such as triallyl isocyanurate.

The above-mentioned transparent thermosetting resin preferably contains various ultraviolet absorbers, antioxidants and antistatic agents from the viewpoints of light resistance, oxidation deterioration resistance and antistatic properties. When the transparent thermosetting resin is the above-mentioned polyolefin-based copolymer, it is preferable that the polyolefin-based copolymer uses a monomer having an ultraviolet absorbing property or an antioxidant property. Preferred examples of such a monomer include a benzophenone-based UV absorber having an unsaturated double bond, a phenylbenzoate-based UV absorber having an unsaturated double bond, and a hindered amino group as a substituent (meth). ) Acrylic acid monomers and the like can be mentioned. These monomers are preferably used in the range of 0.5 to 20 wt% with respect to the total amount of the monomers used to obtain the desired polyolefin-based copolymer.

The transparent thermosetting resin substrate constituting the organic EL device of the present invention may be obtained by any polymerization method and molding method as long as it has the above-mentioned flat surface. The thickness of the target organic E
The thickness can be appropriately selected depending on the application of the L element, but when the transparent thermosetting resin substrate is made of the above-mentioned polyolefin-based copolymer, its thickness is 0.1 in consideration of mechanical characteristics. It is preferably ~ 1.5 mm,
More preferably, it is 1.0 mm.

A moisture-proof inorganic oxide film is formed on the above-mentioned flat surface of the transparent thermosetting resin substrate described above. This moisture-proof inorganic oxide film has a gas barrier property on the transparent thermosetting resin substrate described above in order to prevent oxygen and moisture from entering the organic single-layer part or the organic multilayer part containing the organic light-emitting material described later. It is for giving.
Specific examples of the moisture-proof inorganic oxide film include silicon oxide (SiO _x ), aluminum oxide (Al ₂ O _x ),
Titanium oxide (TiO _x ), zirconium oxide (Zr
O _x ), yttrium oxide (Y ₂ O _x ), ytterbium oxide (Yb ₂ O _x ), magnesium oxide (Mg
A film made of O _x ), tantalum oxide (Ta ₂ O _x ), cerium oxide (CeO _x ) or hafnium oxide (HfO _x ).

The thickness of the moisture-proof inorganic oxide film can be appropriately changed depending on the material of the moisture-proof inorganic oxide film, but is generally in the range of 50 to 2000 angstroms. If the film thickness is too thin, the desired gas barrier property cannot be imparted to the transparent thermosetting resin substrate. On the other hand, if the film thickness is too large, the light transmittance is lowered, and as a result, the brightness of the organic EL element is lowered. The film thickness of the moisture-proof inorganic oxide film is 100 to
It is preferably 1200 Å.

The flatness of the surface of the moisture-proof inorganic oxide film has no unevenness in brightness and an organic EL device having high light emission stability. It is desirable that the flatness of the flexible resin substrate is as high as the flatness of the flat surface. The moisture-proof inorganic oxide film having such flatness can be formed by a sputtering method such as a direct current method, a magnetron method, a high frequency discharge method, a vacuum deposition method, an ion plating method, a plasma CVD method, or the like. it can. Whichever method is used to form the moisture-proof inorganic oxide film, the substrate temperature during film formation is preferably a temperature at which the above-mentioned transparent thermosetting resin substrate does not substantially undergo thermal deformation. If the transparent thermosetting resin substrate undergoes thermal deformation during the formation of the moisture-proof inorganic oxide film, it becomes difficult to obtain an organic EL element having high luminance stability without uneven brightness.

The transparent electrode formed on the above moisture-proof inorganic oxide film has a grain size of 5 as described above.
It is made of a crystalline transparent conductive film or an amorphous transparent conductive film having a thickness of 00 Å or less. This transparent electrode may be made of a crystalline transparent conductive film or may be made of an amorphous transparent conductive film. In addition, the grain size is limited to 500 angstroms or less.
If the grain size exceeds 500 Å,
It is difficult to obtain an organic EL element having high luminance stability without uneven brightness. The "crystalline transparent conductive film having a grain size of 500 angstroms or less" in the present invention means a crystal having a grain size of 500 angstroms or less on the film surface on the side where an organic single layer part or an organic multilayer part described later is formed. Means a transparent conductive film of high quality. The grain size can be obtained by using an electron microscope, an atomic force microscope, or the like.

When the transparent electrode is made of the above crystalline transparent conductive film, the grain size of the crystalline transparent conductive film is 10.
It is preferably ˜500 Å. Further, specific examples of the material thereof include crystalline ITO, tin oxide, zinc oxide, copper iodide and the like, and crystalline ITO is particularly preferable from the viewpoint of transparency and low electric resistance.

The crystalline transparent conductive film having a grain size of 500 angstroms or less is directly formed on the moisture-proof inorganic oxide film by the ECR plasma (electron cyclotron resonance plasma) sputtering method, the high frequency discharge sputtering method or the like. Can be formed. Also,
A grain size of 50 is obtained by a method such as magnetron sputtering, vacuum deposition, or ion plating.
Once a crystalline transparent conductive film having a thickness of more than 0 angstrom is obtained, the crystalline transparent conductive film is irradiated with UV ozone until the grain size becomes 500 angstroms or less, or oxygen ions, nitrogen ions, argon ions, etc. A crystalline transparent conductive film having a grain size of 500 angstroms or less can also be obtained by performing ion irradiation. The condition of UV ozone irradiation is, for example, the main wavelength of the light source is 2537 angstrom, 1849.
Angstrom, introduction amount of oxygen gas in the irradiation tank 10 liter / min, substrate temperature 10 to 30 ° C., irradiation time 10 min to 5
Time. The conditions for ion irradiation are, for example, an irradiation tank internal pressure of 10 ⁻⁶ to 10 ⁻¹ Pa and an irradiation drive voltage of 10 to ¹
The irradiation time is 000 V and the irradiation time is 10 seconds to 1 hour.

In any case of forming the crystalline transparent conductive film, the substrate temperature at the time of forming the transparent thermosetting film is the same as the case of forming the moisture-proof inorganic oxide film. It is preferable that the temperature is such that the resin substrate does not substantially undergo thermal deformation. The above-mentioned UV ozone irradiation and ion irradiation may be performed on the crystalline transparent conductive film having a grain size of 500 angstroms or less. When UV ozone irradiation or ion irradiation is performed, the surface of the crystalline transparent conductive film can be cleaned without damaging the transparent thermosetting resin substrate.

On the other hand, a specific example of the material of the above-mentioned amorphous transparent conductive film is an amorphous oxide film containing indium element and zinc element as main cation elements. Here, the “amorphous transparent conductive film” in the present invention means
It means a transparent conductive film having a structure in which grain boundaries are not observed by morphological observation with an electron microscope, an atomic force microscope, or the like, or a transparent conductive film having a structure in which the lattice constant is not determined by electron beam diffraction or the like.

When the above-mentioned amorphous oxide film containing indium element and zinc element as main cation elements is used as the amorphous transparent conductive film, the atomic ratio of indium in the amorphous oxide film In / ( In + Zn) is 0.
It is preferably 55 to 0.90. When the above atomic ratio is less than 0.55, the conductivity of the film is low, and when it exceeds 0.90, the etching property or wet heat resistance of the film is deteriorated.

The above-mentioned amorphous oxide film containing indium element and zinc element as main cation elements may contain substantially only indium element and zinc element as cation elements. Further, as the cation element other than the zinc element, one or more third elements having a valence of positive trivalence or more may be contained. Specific examples of the third element include tin (Sn),
Examples include aluminum (Al), antimony (Sn), gallium (Ga), germanium (Ge), and titanium (Ti). The content of the third element is preferably such that the atomic ratio (total third element) / (In + Zn + total third element) of the total amount is 0.2 or less. When the atomic ratio of the total amount of the third element exceeds 0.2, the conductivity of the film tends to decrease.

The amorphous transparent conductive film can be directly formed on the moisture-proof inorganic oxide film described above by a method such as ECR plasma (electron cycloton resonance plasma) sputtering method and magnetron sputtering method. At this time, the substrate temperature during film formation may be a temperature at which the above-mentioned transparent thermosetting resin substrate does not substantially undergo thermal deformation for the same reason as in the case of forming the moisture-proof inorganic oxide film. preferable. After forming the amorphous transparent conductive film on the moisture-proof inorganic oxide film, UV ozone irradiation or ion irradiation may be performed as necessary. By performing UV ozone irradiation or ion irradiation, the surface of the amorphous transparent conductive film can be cleaned without damaging the transparent thermosetting resin substrate.

The film thickness of the transparent electrode made of the above-mentioned crystalline transparent conductive film or amorphous transparent conductive film is appropriately selected according to the material thereof so as to obtain desired conductivity and light transmittance. For example, the film thickness of the transparent electrode made of crystalline ITO can be appropriately selected within the range of approximately 100 to 10,000 angstroms. From the viewpoint of increasing the light transmittance, it is particularly preferably 100 to 2000 angstroms. The thickness of the transparent electrode formed of an amorphous oxide film containing indium element and zinc element as main cation elements is such that the atomic ratio In / (In + Zn) of indium in the amorphous oxide film is 0.55. ~ 0.90
When it is, it can be appropriately selected within the range of 3 to 3000 nm. In this case, the film thickness of the transparent electrode made of the amorphous oxide film is preferably 5 to 1000 nm, and particularly preferably 10 to 800 nm.

As the transparent electrode, when forming the above-mentioned crystalline transparent conductive film or amorphous transparent conductive film, use a mask having an opening of a predetermined shape corresponding to the shape of the target transparent electrode. Can be obtained by Further, when the transparent conductive film described above is obtained by performing UV ozone irradiation or ion irradiation after film formation, when the transparent conductive film that is the target of UV ozone irradiation or ion irradiation is formed, A target transparent electrode can be obtained by using a mask having an opening having a predetermined shape corresponding to the shape of the electrode and then performing UV ozone irradiation or ion irradiation.

Alternatively, it is also possible to temporarily form a large-area film made of the above-mentioned crystalline transparent conductive film or amorphous transparent conductive film, and then pattern the film into a desired shape by photolithography or the like. The transparent electrode can be obtained. Further, when a transparent electrode made of the above-mentioned transparent conductive film is obtained by performing UV ozone irradiation or ion irradiation after film formation, a large-area film made of a transparent conductive film to be subjected to UV ozone irradiation or ion irradiation is used. Once the film is formed and patterned into a desired shape by a photolithography method or the like, UV ozone irradiation or ion irradiation is performed, or the large area film is subjected to UV ozone irradiation or ion irradiation and then the photolithography method. The desired transparent electrode can be obtained by patterning into a desired shape by, for example, the like.

In the organic EL device of the present invention, the organic single layer portion or the organic multilayer portion containing the organic light emitting material is formed on the transparent electrode described above, and the organic single layer portion or the organic multilayer portion is opposed to the organic single layer portion or the organic multilayer portion. Electrodes are formed. The organic single layer portion or the organic multilayer portion is formed on the transparent electrode, and the counter electrode is formed on the organic single layer portion or the organic multilayer portion. It is the same as the conventional organic EL element.

That is, the layer structure from the transparent electrode (anode) to the counter electrode (cathode) in the organic EL element of the type in which the transparent substrate side is the light extraction surface is largely the layer structure of the following (1) to (4). Although it can be different, the layer structure from the transparent electrode (anode) to the counter electrode (cathode) in the organic EL device of the present invention can be any of the following (1) to (4). (1) Transparent electrode (anode) / light emitting layer / counter electrode (cathode) (2) Transparent electrode (anode) / hole transport layer / light emitting layer / counter electrode (cathode) (3) Transparent electrode (anode) / light emitting layer / Electron injection layer / Counter electrode (cathode) (4) Transparent electrode (anode) / Hole transport layer / Light emitting layer / Electron injection layer / Counter electrode (cathode)

Here, the light emitting layer is usually formed of one or more kinds of organic light emitting materials, and a mixture of the organic light emitting material and the hole transport material and / or the electron injecting material, or the mixture or the organic light emitting material. It may be formed of a polymer material in which is dispersed. In some cases, a sealing layer is provided around the organic EL element having the above-described layer structure so as to cover the organic EL element and prevent moisture and oxygen from entering the organic EL element.

In the organic EL device of the type (1) above, the light emitting layer corresponds to the “organic single layer portion containing the organic light emitting material” in the present invention, and in the organic EL device of the type (2) above, holes are generated. The transport layer and the light emitting layer correspond to the "organic multilayer portion containing the organic light emitting material" in the present invention, and the organic E of the type (3) above is used.
In the L element, the light emitting layer and the electron injection layer correspond to the “organic multilayer portion containing the organic light emitting material” in the present invention, and in the organic EL element of the type (4) above, the hole transport layer, the light emitting layer and the electron injection layer. The layer corresponds to the “organic multilayer portion containing the organic light emitting material” in the present invention. Various materials can be used as the materials of the light emitting layer, the hole transport layer, the electron injection layer, and the counter electrode (cathode).

For example, the organic compound that can be used as the material of the light emitting layer (organic light emitting material) is not particularly limited, but a fluorescent brightening agent such as a benzothiazole type, a benzimidazole type, or a benzoxazole type is used. Specific examples of these include 2,5-bis (5,7-di-
t-pentyl-2-benzoxazolyl) -1,3,4
-Thiadiazole, 4,4'-bis (5,7-t-pentyl-2-benzoxazolyl) stilbene, 4,4 '
-Bis [5,7-di- (2-methyl-2-butyl) -2
-Benzoxazolyl] stilbene, 2,5-bis (5,7-di-t-pentyl-2-benzoxazolyl) thiophene, 2,5-bis [5-α, α-dimethylbenzyl-2- Benzoxazolyl] thiophene, 2,
5-bis [5,7-di- (2-methyl-2-butyl)-
2-benzoxazolyl] -3,4-diphenylthiophene, 2,5-bis (5-methyl-2-benzoxazolyl) thiophene, 4,4′-bis (2-benzoxazolyl) biphenyl, 5-methyl-2- [2- [4-
(5-Methyl-2-benzoxazolyl) phenyl] vinyl] benzoxazole, 2- [2- (4-chlorophenyl) vinyl] naphtho [1,2-d] oxazole and other benzoxazoles, 2,2 ′ Benzothiazoles such as-(p-phenylenedivinylene) -bisbenzothiazole, 2- [2- [4- (2-benzimidazolyl))
Phenyl] vinyl] benzimidazole, 2- [2-
Examples include fluorescent whitening agents such as benzimidazole-based agents such as (4-carboxyphenylvinyl] benzimidazole.

Metal chelated oxinoid compounds are also used as organic light emitting materials, examples of which include tris (8-quinolinol) aluminum, bis (8-quinolinol) magnesium, and bis (benzo [f] -8-.
Quinolinol) zinc, bis (2-methyl-8-quinolinolate) aluminum oxide, tris (8-quinolinol) indium, tris (5-methyl-8-quinolinol) aluminum, 8-quinolinol lithium, tris (5-chloro-8-). 8-hydroxyquinoline-based metal complexes such as quinolinol) gallium, bis (5-chloro-8-quinolinol) calcium, poly [zinc (II) -bis (8-hydroxy-5-quinolinonyl) methane], and dilithium epinetridione. Etc.

A styrylbenzene compound is also used as an organic light emitting material, and examples thereof include 1,4-bis (2-methylstyryl) benzene and 1,4-bis (3).
-Methylstyryl) benzene, 1,4-bis (4-methylstyryl) benzene, distyrylbenzene, 1,4-
Bis (2-ethylstyryl) benzene, 1,4-bis (3-ethylstyryl) benzene, 1,4-bis (2-
Methylstyryl) -2-methylbenzene, 1,4-bis (2-methylstyryl) -2-ethylbenzene and the like can be mentioned.

Further, a distyrylpyrazine derivative is also used as an organic light emitting material, and examples thereof include 2,
5-bis (4-methylstyryl) pyrazine, 2,5-bis (4-ethylstyryl) pyrazine, 2,5-bis [2
-(1-naphthyl) vinyl] pyrazine, 2,5-bis (4-methoxystyryl) pyrazine, 2,5-bis [2
Examples include-(4-biphenyl) vinyl] pyrazine and 2,5-bis [2- (1-pyrenyl) vinyl] pyrazine.

Other organic light emitting materials include, for example, specific polyphenyl compounds, 12-phthaloperinone,
1,4-diphenyl-1,3-butadiene, 1,1,
4,4-Tetraphenyl-1,3-butadiene, naphthalimide derivative, perylene derivative, oxadiazole derivative, aldazine derivative, pyrazirine derivative, cyclopentadiene derivative, pyrrolopyrrole derivative, styrylamine derivative, coumarin compound, and 1, 4-phenylene dimethyridine, 4,4'-phenylene dimethyridine, 2,5-xylylene dimethyridine, 2,6-naphthylene dimethyridine, 1,4-biphenylene dimethyridine, 1,4-p-terephenylene dimethyrin Lysine, 9,1
0-anthracene diyl dimethylidine, 4,4'-
Aromatic dimethylidyne compounds such as (2,2-di-t-butylphenylvinyl) biphenyl and 4,4 ′-(2,2-diphenylvinyl) biphenyl, their derivatives, and other specific polymer compounds. be able to.

As a method for forming a light emitting layer using the above organic light emitting material, a known method such as a vapor deposition method, a spin coating method, a casting method or an LB method can be applied. The light emitting layer is preferably a molecular deposition film.
Here, the molecular deposition film refers to a thin film formed by deposition from a material compound in a gaseous state or a film formed by solidification from a material compound in a solution state or a liquid phase state. Can be distinguished from a thin film (molecule accumulation film) formed by the LB method by a difference in an aggregated structure and a higher-order structure and a functional difference caused by the difference. The light emitting layer can also be formed by dissolving a binder such as a resin and an organic light emitting material in a solvent to form a solution, and then thinning the solution by a spin coating method or the like. The thickness of the light emitting layer thus formed is not particularly limited and can be appropriately selected depending on the situation, but is usually 5
The range of nm to 5 μm is preferable.

In the light emitting layer of the organic EL element, holes can be injected from the transparent electrode (anode) or the hole transport layer and electrons can be injected from the counter electrode (cathode) or the electron injection layer when an electric field is applied. It has an injection function that allows injection, a transport function that moves injected charges (electrons and holes) by the force of an electric field, a field for recombination of electrons and holes, and a light emitting function that connects this to light emission. ing. Note that there may be a difference between the ease of injecting holes and the ease of injecting electrons. In addition, although the transport function represented by the mobility of holes and electrons may be large or small, it is preferable to move at least one of them.

As a material of the hole transporting layer provided between the transparent electrode (anode) and the light emitting layer as required, a material conventionally used as a hole injecting material of an optical transmission material or an organic EL element is used. Any known material used for the hole transport layer can be selected and used.
The material of the hole transport layer has one of hole injection and electron barrier properties, and may be either an organic substance or an inorganic substance.

Specific examples include, for example, imidazole derivative, polyarylalkane derivative, pyrazoline derivative and pyrazolone derivative, phenylenediamine derivative, arylamine derivative, amino-substituted chalcone derivative, oxazole derivative, styrylanthracene derivative, fluorenone derivative, hydrazone derivative, stilbene derivative. Derivative,
Silazane derivative, polysilane type, aniline type copolymer,
Specific conductive polymer oligomers such as thiophene oligomer can be cited.

As the material of the hole transport layer, the above-mentioned materials can be used, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound or a styrylamine compound, particularly an aromatic tertiary amine compound. .

Examples of the porphyrin compound include porphyrin, 1,10,15,20-tetraphenyl-
21H, 23H-porphin copper (II), 1,10,1
5,20-tetraphenyl-21H, 23H-porphine zinc (II), 5,10,15,20-tetrakis (pentafluorophenyl) -21H, 23H-porphine, silicon phthalocyanine oxide, aluminum phthalocyanine chloride, phthalocyanine (metal-free ),
Examples thereof include dilithium phthalocyanine, copper tetramethylphthalocyanine, copper phthalocyanine, chromium phthalocyanine, zinc phthalocyanine, lead phthalocyanine, titanium phthalocyanine oxide, magnesium phthalocyanine, and copper octamethylphthalocyanine.

Typical examples of the aromatic tertiary amine compound and the styrylamine compound are N, N,
N ', N'-tetraphenyl-4,4'-diaminophenyl, N, N'-diphenyl-N, N'-bis- (3-
Methylphenyl)-(1,1'-biphenyl) -4,
4'-diamine, 2,2-bis (4-di-p-tolylaminophenyl) propane, 1,1-bis (4-di-p-
Tolylaminophenyl) cyclohexane, N, N,
N ', N'-tetra-p-tolyl-4,4'-diaminobiphenyl, 1,1-bis (4-di-p-tolylaminophenyl) -4-phenylcyclohexane, bis (4-
Dimethylamino-2-methylphenyl) phenylmethane, bis (4-di-p-tolylaminophenyl) phenylmethane, N, N'-diphenyl-N, N'-di (4-
Methoxyphenyl) -4,4'-diaminobiphenyl,
N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether, 4,4'-bis (diphenylamino) quadriphenyl, N, N, N-tri (p-
Tolyl) amine, 4- (di-p-tolylamino) -4 '
-[4 (di-p-tolylamino) styryl] stilbene, 4-N, N-diphenylamino- (2-diphenylvinyl) benzene, 3-methoxy-4'-N, N-diphenylaminostilbenzene, N-phenyl Examples thereof include carbazole. Further, the above-mentioned aromatic dimethylidyne compound shown as the organic light emitting material can also be used as the material of the hole transport layer.

The hole transport layer can be formed by thinning the above compound by a known method such as a vacuum vapor deposition method, a spin coating method, a casting method or an LB method. The thickness of the hole transport layer is not particularly limited, but is usually 5 nm to 5 μm. This hole transport layer is
It may have a single-layer structure composed of one or more of the above-mentioned materials, or may have a multi-layer structure composed of a plurality of layers having the same composition or different compositions.

The electron injection layer, which is provided between the light emitting layer and the counter electrode (cathode) as required, has a function of transmitting the electrons injected from the counter electrode (cathode) to the light emitting layer. As the material, any one of conventionally known compounds can be selected and used.

Specific examples include triazole derivatives, oxadiazole derivatives, nitro-substituted fluorenone derivatives, anthraquinodimethane derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, heterocyclic tetracarboxylic acid anhydrides such as naphthaleneperylene, and carbodiimides. , Fluorenylidene methane derivatives, anthraquinodimethane derivatives and anthrone derivatives, oxadiazole derivatives, and other specific electron transfer compounds.

Metal complexes of 8-quinolinol derivatives, specifically, tris (8-quinolinol) aluminum, tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol). ) Aluminum, tris (2-methyl-8-quinolinol) aluminum, and the like, and metal complexes in which the central metal of these metal complexes is replaced with In, Mg, Cu, Ca, Sn, or Pb, etc. are also materials for the electron injection layer. Can be used as In addition, metal-free or metal phthalocyanine, or those whose terminal is substituted with an alkyl group, a sulfone group, or the like is also desirable. Also, distyrylpyrazine derivatives exemplified as the material of the light emitting layer,
It can be used as a material for the electron injection layer.

The electron injection layer can be formed by thinning the above compound by a known method such as a vacuum vapor deposition method, a spin coating method, a casting method and an LB method. The thickness of the electron injection layer is not particularly limited, but is usually 5 nm to 5 μm. The electron injection layer may have a single-layer structure composed of one or more of the above-mentioned materials, or a multi-layer structure composed of a plurality of layers having the same composition or different compositions.

The material for the hole transport layer is p-type-S.
It is also possible to use an inorganic compound such as i, p-type-SiC,
Also as a material of the electron injection layer, n-type-Si, n-type-SiC
It is also possible to use an inorganic compound such as. Specific examples of the inorganic material for the hole transport layer and the inorganic material for the electron injection layer include the inorganic semiconductors disclosed in International Publication WO90-05998.

As a material for the counter electrode (cathode), a metal, an alloy, an electrically conductive compound, a mixture thereof or the like having a small work function (for example, 4 eV or less) is preferably used. Specific examples include sodium, sodium-potassium alloy, magnesium, lithium, alloys or mixed metals of magnesium and silver, magnesium-copper mixture, aluminum, Al / Al ₂ O ₃ , indium,
Examples thereof include rare earth metals such as ytterbium.

The counter electrode can be formed by thinning the above-mentioned material by a method such as a vacuum vapor deposition method or a sputtering method, but it is particularly preferably formed by a vacuum vapor deposition method. The counter electrode does not have to be substantially transparent to the EL light from the light emitting layer, and its film thickness depends on the material of the counter electrode, but is usually 10 n.
It can be appropriately selected within the range of m to 1 μm. The sheet resistance of the counter electrode is preferably several hundreds Ω / □ or less. The size of the work function used as a reference when selecting the material of the counter electrode is not limited to 4 eV.

In the organic EL device of the present invention, on the above-mentioned transparent electrode, the organic single-layer part (layer consisting of only the light-emitting layer) or the organic multi-layer part (layer including only the light-emitting layer) containing the above-mentioned organic light-emitting material,
A layer having at least one of a hole transport layer and an electron injection layer) is formed, and the counter electrode described above is provided on the organic single layer portion or the organic multilayer portion. Like the conventional organic EL element, the organic EL element may have a sealing layer for preventing intrusion of moisture or oxygen into the element.

Specific examples of the material for the sealing layer include a copolymer obtained by copolymerizing a monomer mixture containing tetrafluoroethylene and at least one comonomer, and a fluorine-containing copolymer having a cyclic structure in its main chain. Copolymer, polyethylene, polypropylene, polymethylmethacrylate, polyimide, polyurea, polytetrafluoroethylene,
Polychlorotrifluoroethylene, polydichlorodifluoroethylene, a copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, a water-absorbing substance having a water absorption rate of 1% or more, and a moisture-proof substance having a water absorption rate of 0.1% or less, I
n, Sn, Pb, Au, Cu, Ag, Al, Ti, Ni
Metals such as MgO, SiO, SiO ₂ , Al ₂ O ₃ , G
eO, NiO, CaO, BaO, Fe ₂ O ₃ , Y
₂ O ₃ , metal oxides such as TiO ₂ , MgF ₂ , LiF,
Metal fluorides such as AlF ₃ and CaF ₂ , liquid fluorinated carbons such as perfluoroalkane, perfluoroamine, and perfluoropolyether, and those in which an adsorbent that adsorbs water and oxygen is dispersed in the liquid fluorinated carbon. Is mentioned.

In forming the sealing layer, a vacuum deposition method, a spin coating method, a sputtering method, a casting method, MBE
(Molecular beam epitaxy) method, cluster ion beam method,
Ion plating method, plasma polymerization method (high frequency excitation ion plating method), reactive sputtering method,
A plasma CVD method, a laser CVD method, a thermal CVD method, a gas source CVD method, or the like can be applied as appropriate. In the case of using liquid fluorinated carbon or a material in which an adsorbent for adsorbing moisture or oxygen is dispersed in the liquid fluorinated carbon as a material of the sealing layer, the organic EL element formed on the substrate (another EL element) is used. Outside the sealing layer), a housing material is provided to cover the organic EL element in cooperation with the substrate while forming a gap between the substrate and the organic EL element. It is preferable that the sealing layer is formed by filling the space formed by the housing material with the liquid fluorinated carbon or the liquid fluorinated carbon in which an adsorbent for adsorbing moisture or oxygen is dispersed. As the housing material, a material made of glass or a polymer (for example, ethylene trifluoride chloride) having a small water absorption is preferably used. When using a housing material, only the housing material may be provided without providing the above-described sealing layer, or after the housing material is provided, a space formed by the housing material and the substrate may be used. A layer of an adsorbent for adsorbing oxygen or water may be provided, or particles of the adsorbent may be dispersed.

The organic EL element of the present invention described above is an organic EL element which is free from uneven brightness and has high emission stability even though a resin substrate is used as a transparent substrate. . The reason why it is possible to obtain a device having high luminance stability without uneven brightness is presumed as follows.

That is, in the organic EL device of the present invention, since the transparent thermosetting resin substrate having a flat surface is used as the transparent resin substrate, the above-mentioned flat surface of the transparent thermosetting resin substrate is used as described above. To form a moisture-proof inorganic oxide film, and by forming a transparent electrode on the moisture-proof inorganic oxide film as described above, the surface is flatter than that of the transparent electrode formed on the thermoplastic resin substrate. A highly transparent electrode can be obtained. Then, in the organic EL element obtained by sequentially laminating the organic single layer portion or the organic multilayer portion and the counter electrode (cathode) on the transparent electrode by the method described above, the gap between the transparent electrode and the counter electrode is It is expected to be relatively uniform, and the voltage across the transparent and counter electrodes will also be relatively uniform. If the voltage applied between the transparent electrode and the counter electrode is relatively uniform, it is unlikely that a high voltage is locally generated between the transparent electrode and the counter electrode, and as a result, there is no uneven brightness. An organic EL device having high light emission stability can be obtained. Therefore,
By manufacturing an organic EL element as described above using the transparent thermosetting resin substrate having a flat surface described above as the transparent resin substrate, it is possible to obtain an organic EL element having high luminance stability without uneven brightness. It will be possible.

The term "there is no brightness unevenness" in the present invention means that there is no non-light emitting area having a diameter of 50 μm or more and there is no difference in brightness and color depending on the position in the light emitting surface.
The phrase “highly stable in light emission” as used in the present invention means that there is no “brightness unevenness” in the present invention even after lighting for 50 hours continuously from initial lighting (excluding aging). The presence or absence of the non-light emitting area and the size of the non-light emitting area can be determined or measured by causing the device to emit light with a brightness of 100 cd / m ² and observing the light emitting surface at this time using a brightness meter. Further, the presence or absence of a difference in brightness and color depending on the position on the light emitting surface can be similarly determined or measured.

[0059]

Embodiments of the present invention will be described below. Example 1 (1) Transparent Thermosetting Resin Substrate As a transparent resin substrate, an acrylic transparent thermosetting resin substrate (total light transmittance 93%) having a size of 30 × 25 × 1 mm was prepared. This acrylic transparent thermosetting resin substrate was cut out from Clarax precision plate flat S type (trade name) manufactured by Nitto Jushi Kogyo Co., Ltd., and the precision plate was precisely molded by the casting polymerization method. is there. Both sides of the acrylic transparent thermosetting resin substrate are “flat surfaces” in the present invention, and were obtained by using a stylus type surface roughness meter (trade name: DEKTAK3030) manufactured by Sloan. The root-mean-square value of the surface roughness of the flat surface is 100.
As a result of morphological observation with an atomic force microscope, the number of projections of 600 angstroms or more present in an area of 500 μm square on the flat surface was 15 angstroms.

(2) Formation of Moisture-Proof Inorganic Oxide Film Silicon oxide (S) is formed on one surface of the acrylic transparent thermosetting resin substrate of (1) above by a reactive sputtering method using Si as a sputtering target.
A moisture-proof inorganic oxide film made of iO _x ) having a film thickness of 600 angstrom was formed. In the reactive sputtering at this time, an acrylic transparent thermosetting resin substrate is attached to a sputtering device, the pressure in the vacuum chamber is reduced to 1 × 10 ⁻³ Pa or less, and Ar gas (purity 99.99%) and O 2 are added. ₂
Gas mixed with gas (purity 99.99%) (Ar: O ₂ =
1000: 2.8 (volume ratio), the vacuum pressure is 1.0 × 10
After introducing into the vacuum chamber until the pressure reaches ^-1 Pa, the target applied voltage is 400 V and the substrate temperature is 80 ° C.

(3) Formation of transparent electrode Mixture of indium oxide and zinc oxide as a sputtering target (atomic ratio of In: In / (In + Zn) =
By a DC magnetron sputtering method using a sintered body of 0.80) and having a film thickness of 250 nm containing indium element and zinc element as main cation elements on the moisture-proof inorganic oxide film formed in (2) above. An amorphous oxide film was formed. In the DC magnetron sputtering at this time, the acrylic transparent thermosetting resin substrate having the moisture-proof inorganic oxide film formed in the above (2) is mounted on a DC magnetron sputtering device and the inside of the vacuum chamber is set to 1 ×.
The pressure was reduced to 10 ⁻³ Pa or less, and Ar gas (purity 99.9) was used.
9%) and O ₂ gas (purity 99.99%) mixed gas (Ar: O ₂ = 1000: 2.8 (volume ratio)) is evacuated to a vacuum pressure of 1.0 × 10 ⁻¹ Pa. After introduction into the bath, the target applied voltage was 420 V and the substrate temperature was 60 ° C.

The In atomic ratio In / (In + Zn) in the obtained amorphous oxide film was determined by ICP analysis (inductively coupled plasma emission spectroscopic analysis; model used was SPS-1500VR manufactured by Seiko Instruments Inc.). The same value as the sputtering target was 0.80. In addition, the fact that the oxide film is an amorphous oxide film means that the X-ray diffraction measurement (the model used is the Rotaflex RU-2 manufactured by Rigaku Corporation).
00B).

Next, the acrylic transparent thermosetting resin substrate having the amorphous oxide film formed thereon is ultrasonically cleaned using isopropyl alcohol as a cleaning liquid and then spray-dried, and thereafter, the main wavelength is 2537 angstroms, UV ozone irradiator using a 1849 Å light source (UV manufactured by Sacom International Laboratories
-300), the above-mentioned amorphous oxide film was irradiated with UV ozone under the conditions of a substrate temperature of room temperature, an O ₂ gas introduction rate of 10 l / min, and a treatment time of 10 minutes. As a result, the surface of the amorphous oxide film was cleaned and the target transparent electrode was obtained.

(4) Formation of Organic EL Element A commercially available vapor deposition apparatus (Japan Vacuum Technology Co., Ltd.) was used for the acrylic transparent thermosetting resin substrate having the transparent electrode formed in the above (3).
Fixed on a substrate holder made of molybdenum and placed on a resistance heating boat made of molybdenum.
Methylphenyl)-[1,1′-biphenyl] -4,
20% of 4′-diamine (hereinafter abbreviated as “TPD”)
Put 0 mg in a different molybdenum resistance heating boat and use tris (8-quinolinol) aluminum (hereinafter "Al
abbreviated as “q ₃ ”. ) 200 mg and put 1 in the vacuum chamber
The pressure was reduced to × 10 ⁻⁴ Pa.

After that, the boat with TPD is set to 215.
The temperature was increased to 220 ° C., and TPD was vapor-deposited on the above transparent electrode at a vapor deposition rate of 1 to 3 Å / sec to form a hole transport layer having a thickness of 600 Å. At this time, the substrate temperature was room temperature. Without taking this out of the vacuum chamber, a light emitting layer having a film thickness of 600 Å and made of Alq ₃ was formed on the hole transport layer. The vapor deposition conditions at this time are a boat temperature of 230 ° C. and a vapor deposition rate of 0.1 to
The substrate temperature was room temperature, 0.2 angstrom / sec. This was taken out of the vacuum chamber, a stainless steel mask was placed on the light emitting layer, and fixed again to the substrate holder.

Next, 1 g of magnesium ribbon was put in a resistance heating boat made of molybdenum, and 500 mg of silver wire was attached to another tungsten basket. Then, the pressure in the vacuum chamber was reduced to 2 × 10 ⁻⁴ Pa, and
Simultaneously with the vapor deposition rate of angstrom / sec, magnesium was vapor-deposited from the other molybdenum boat by the resistance heating method at a vapor deposition rate of 14 angstrom / sec. As a result, a counter electrode made of a mixed metal of magnesium and silver and having a film thickness of 1500 angstrom was formed on the light emitting layer, and the intended organic EL device was obtained. In this organic EL element, the organic multilayer portion is formed by the hole transport layer made of TPD and the light emitting layer made of Alq ₃ .

(5) Evaluation Using the transparent electrode of the organic EL device obtained in (4) above as an anode and the counter electrode as a cathode, the device has a brightness of 100.
A direct current electric field was applied to the organic EL device in the atmosphere so as to be cd / m ^2, and the conversion efficiency η at this time was determined by the following equation.

(Equation 1)

Further, the light emitting surface at this time was observed by using a luminance meter (CS-100 manufactured by Minolta Camera Co., Ltd.) to determine the uniformity of light emission, that is, the presence or absence of a non-light emitting area and the position within the light emitting surface. The presence or absence of a difference in brightness and color was evaluated. Furthermore, the uniformity of light emission after continuous driving at a brightness of 100 cd / m ² for 50 hours was evaluated. Table 1 shows the results.

Example 2 On one side of an acrylic transparent thermosetting resin substrate having the same quality and shape as the acrylic transparent thermosetting resin substrate used in Example 1, moistureproofness was applied in the same manner as in Example 1 (2). After forming an inorganic oxide film, an EC using a sintered body made of a composite oxide of indium oxide and tin oxide (ITO: In and Sn atomic ratio In / Sn = 9/1) as a sputtering target
A transparent electrode made of a crystalline ITO film having a film thickness of 120 nm was formed on the moisture-proof inorganic oxide film by the R plasma sputtering method.

In the sputtering at this time, the acrylic transparent thermosetting resin substrate on which the moisture-proof inorganic oxide film was formed is mounted on a sputtering apparatus and the inside of the vacuum chamber is set to 1 × 10.
^The pressure was reduced to ^-3 Pa or less, and Ar gas (purity 99.99) was used.
%) And O ₂ gas (purity 99.99%) mixed gas (A
r: O ₂ = 1000: 2.8 (volume ratio) was introduced into the vacuum chamber until the vacuum pressure reached 2.0 × 10 ⁻¹ Pa,
The target applied voltage was 420 V, and the substrate temperature was 80 ° C.

Crystalline ITO formed as described above
The grain size of the film was determined using an electric microscope and was found to be 200 to 500 angstroms. Also,
Each grain (microcrystalline grain) had a spherical or spheroidal shape. Then, the hole transport layer, the light emitting layer and the counter electrode were formed on the transparent electrode made of the crystalline ITO film in the same manner as in Example 1 (4) to obtain the target organic EL device.

Example 1 of this organic EL device
The same items as those measured or evaluated in (5) were used in Example 1.
It was measured or evaluated in the same manner as in (5). Table 1 shows the results.

Comparative Example 1 PET, which is one of the thermoplastic resins, is used as the transparent resin substrate.
30x made of (polyethylene terephthalate)
25 x 1 mm substrate (hereinafter, this substrate is referred to as "PET substrate"
That. ) Was used. The root-mean-square value of the surface roughness of this PET substrate was determined in the same manner as in Example 1 (1), and it was 410 Å. Also, the P
Exists in a 500 μm square area on the ET substrate 6
The number of protrusions of 00 angstrom or more was determined in Example 1 (1).
It was 110 when it asked in the same way as. Therefore, this PET substrate does not have the “flat surface” in the present invention. A transparent electrode composed of a moisture-proof inorganic oxide film and a crystalline ITO film was formed on one surface of the PET substrate in the same manner as in Example 2 to obtain an organic EL device. For this organic EL device, the same items as those measured or evaluated in Example 1 (5) were measured or evaluated in the same manner as in Example 1 (5). Table 1 shows the results.

[0074]

[Table 1]

As is clear from Table 1, the organic EL elements obtained in Examples 1 and 2 have a higher conversion efficiency η than the organic EL elements obtained in Comparative Example 1 and the initial Both the uniformity of light emission and the uniformity of light emission after continuous driving for 50 hours are superior to those of the organic EL device obtained in Comparative Example 1. Particularly, regarding the uniformity of light emission, the organic EL of Comparative Example 1 was used.
In the device, a non-light emitting region was already observed in the initial stage, and the ratio thereof increased to 50% or more after continuous driving for 50 hours, whereas each organic EL of Example 1 and Example 2
In the device, no light-emitting region was observed not only in the initial stage but also after continuous driving for 50 hours. In addition, in each of the organic EL devices of Example 1 and Example 2, no difference in brightness and color depending on the position in the light emitting surface was observed even after being continuously driven for 50 hours in the initial stage.
As described above, each of the organic EL elements of Example 1 and Example 2 has no uneven brightness and high emission stability.

[0076]

As described above, the organic EL of the present invention
Although the element uses a transparent resin substrate as the transparent substrate, it is an element that can obtain an element with high luminance stability without uneven brightness. Therefore, according to the present invention, it is possible to provide an organic EL element which is lighter in weight and excellent in impact resistance than an organic EL element using a glass substrate as a transparent substrate, has no uneven brightness, and has high emission stability. Become.

Claims (5)

[Claims] 1. A transparent resin substrate, a transparent electrode formed on one surface of the transparent resin substrate through a moisture-proof inorganic oxide film, and an organic single layer portion or an organic multilayer portion containing an organic light emitting material. And a counter electrode formed on the transparent electrode, wherein the transparent resin substrate is made of a transparent thermosetting resin substrate having a flat surface, and the moisture-proof inorganic is formed on the flat surface of the transparent thermosetting resin substrate. An organic EL device having an oxide film formed thereon, wherein the transparent electrode comprises a crystalline transparent conductive film or an amorphous transparent conductive film having a grain size of 500 angstroms or less. 2. A transparent thermosetting resin substrate has a flat surface having a root-mean-square value of surface roughness of 300 angstroms or less, and 600 angstroms or more existing in a 500 μm square area on the flat surface. The number of protrusions is 2
The organic EL device according to claim 1, wherein the number is 0 or less. 3. The organic EL device according to claim 1, wherein the transparent thermosetting resin substrate is made of a polyolefin-based transparent thermosetting resin. 4. The organic EL device according to claim 1, wherein the transparent electrode is made of a crystalline ITO film. 5. The transparent electrode is made of an amorphous oxide film containing indium element and zinc element as main cation elements, and the atomic ratio In / (In + Zn) of indium in the amorphous oxide film is 0. The organic E according to any one of claims 1 to 4, which is 55 to 0.90.
L element.