JP2006279007A - Organic electroluminescent element, display device, and lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL (electroluminescent) element having high emission luminance, few dark spots and a long lifetime, and to provide a display device and a lighting device that use the same. <P>SOLUTION: In an organic electroluminescence element, having a cathode and an anode on a substrate and having a plurality of organic layers between them, the organic electroluminescence element is a layer, obtained by coating and polymerizing a compound in which at least one of the organic layers has at least one polymerizable group, and containing organic molecules having repeating units of 10 or smaller. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic electroluminescence element, a display device using the organic electroluminescence element, and an illumination apparatus.

  Conventionally, there is an electroluminescence display (ELD) as a light-emitting electronic display device. Examples of the constituent elements of ELD include inorganic electroluminescent elements and organic electroluminescent elements (hereinafter also referred to as organic EL elements).

  An organic EL device has a structure in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, and injects electrons and holes into the light emitting layer and recombines them to generate excitons. This is an element that emits light by utilizing light emission (fluorescence / phosphorescence) when the exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts, and is self-luminous. In addition, it is attracting attention from the viewpoints of space saving, portability and the like because it is a thin film type complete solid element with a wide viewing angle and high visibility.

  For example, an EL element that forms an organic thin film by vapor deposition of an organic compound is known (Applied Physics Letters, 51, p. 913- (1987)). The organic EL device described in this document has a laminated structure of an electron transport material and a hole transport material, and its light emission characteristics are greatly improved as compared with a conventional single layer type device. In this stacked element, an element is formed by evaporating a low molecular organic material as an element material.

  In addition, a technique for forming an element by evaporating organic molecules having 10 or less repeating units generated by polymerizing a compound having a polymerizable group is known (see, for example, Patent Document 1). Further, a technique is known in which a compound having a polymerizable group is polymerized to provide a first layer, and a compound having a polymerizable group is polymerized thereon to provide a second layer (for example, Patent Document 2). reference.).

  However, such a technique using vapor deposition has major problems in the element production process in terms of material utilization efficiency, large area, high definition, and the like.

  Nature, 397 (1999) 121 describes that a π-electron conjugated polymer such as polyparaphenylene vinylene (PPV) or a derivative thereof (MEH-PPV) is used as a light emitting material. Etc. have begun to be used partially. Since these polymer materials can be formed by a casting method, they have not only a merit in the production process but also a merit that durability is better than that of a low molecular weight light emitting material. However, when an organic polymer material is applied, it has the disadvantages of low solubility in a solvent and low luminous efficiency. In order to avoid this problem, there is a method of insolubilizing and preventing elution by polymerizing after application using a polymer precursor. As an example of this, a method using a PPV (p-phenylene vinylene) precursor proposed by Cambridge Display Technology may be mentioned. This method is described in ORGANIC ELECTRO-LUMINESCENT MATERIALS AND DEVICES, 1997, p. 73-. However, this method limits the structure of the polymer and cannot be applied to various compounds for forming a light emitting device.

In addition, as another method, there is a method in which elution is prevented by forming a polymer using a monomer and then insolubilizing it by polymerizing (for example, see Patent Documents 3 and 4). With this method, it is possible to take a laminated structure and the luminous efficiency is improved. However, it is still not sufficient, and there is a problem that a dark spot is easily generated and the interface is disturbed, resulting in a short lifetime.
JP-A-5-247547 JP 2004-103401 A Japanese Patent Laid-Open No. 2003-73666 JP 2003-86377 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an organic EL light emitting element having high emission luminance, few dark spots, and long life, and a display device and an illumination device using the same. It is to be.

  The above object of the present invention has been achieved by the following constitution.

(Claim 1)
In an organic electroluminescence device having a cathode and an anode on a substrate and having a plurality of organic layers between them, a repeating unit obtained by coating and polymerizing a compound in which at least one of the organic layers has at least one polymerizable group An organic electroluminescence device, which is a layer containing 10 or less organic molecules.

(Claim 2)
On the organic layer (first layer), another organic layer (second layer) having 10 or less repeating units is laminated by applying and polymerizing a compound containing at least one polymerizable group. The organic electroluminescent element according to claim 1, wherein

(Claim 3)
In an organic electroluminescence device having a cathode and an anode on a substrate and having a plurality of organic layers therebetween, the organic layer (first layer) is coated with a polymerizable group or a compound having a reactive group and polymerized. After that, another organic layer (second layer) is formed by applying and polymerizing a compound having a polymerizable group or a reactive group, and a part of the interface of each layer is shared. An organic electroluminescence element which is bonded through bonding.

(Claim 4)
The organic electroluminescent element according to claim 1, wherein the polymerizable group is a vinyl group.

(Claim 5)
The organic electroluminescence device according to claim 1, wherein the coating is performed by ink jet recording.

(Claim 6)
The organic electroluminescence device according to any one of claims 1 to 5, wherein the polymerization is performed by energy irradiation.

(Claim 7)
The organic electroluminescence device according to claim 6, wherein the energy irradiation is irradiation of ultraviolet rays, electrons, ions, heat, a radical beam or radiation.

(Claim 8)
8. The compound according to claim 2, wherein the compound of the first layer is a compound having an aromatic tertiary amine structure, and the compound of the second layer is a compound having an organometallic complex structure. 2. The organic electroluminescence device according to item 1.

(Claim 9)
The organic electroluminescent device according to claim 8, wherein the first layer or the second layer further contains a phosphorescent compound.

(Claim 10)
The organic electroluminescence device according to claim 2, wherein the first layer is an electron transport layer and the second layer is a hole transport layer.

(Claim 11)
The organic electroluminescence device according to any one of claims 1 to 10, wherein the substrate is a transparent gas barrier film.

(Claim 12)
Luminescence is white, The organic electroluminescent element of any one of Claims 1-11 characterized by the above-mentioned.

(Claim 13)
A display device comprising the organic electroluminescence element according to claim 12.

(Claim 14)
An illuminating device comprising the organic electroluminescence element according to claim 12.

(Claim 15)
A display device comprising the lighting device according to claim 14 and a liquid crystal element as a display means.

  According to the present invention, it was possible to provide an organic EL light emitting element having high emission luminance, few dark spots, and a long lifetime, and a display device and an illumination device using the organic EL light emitting element.

  Hereinafter, each component of the present invention will be described in detail.

  In the present invention, a compound having at least one polymerizable group (raw material for organic EL) is applied and polymerized by applying irradiation energy thereto to form an organic layer containing organic molecules having 10 or less repeating units. This is a basic feature. Further, in the case of laminating organic layers, after forming the first organic layer, the second organic layer is formed through the same process of applying and polymerizing a compound having at least one polymerizable group. It is said. Furthermore, when laminated according to the present invention, the third characteristic is that a part of the first organic layer and the second organic layer are bonded via a covalent bond at the interface. In addition to these, the organic layer is formed by coating, and the coating by ink jet recording is particularly preferable.

  The polymerization reaction according to the present invention is performed by energy irradiation. Examples of energy irradiation include ultraviolet light, electrons, ions, heat, radical beam, or radiation energy. Among these, the electron energy means a current supplied when the light emitting element is driven, and specifically, an anion radical of a polymerizable compound formed by electrons injected from the cathode or a positive ion injected from the anode. The polymerization reaction proceeds with the radical cation of the polymerizable compound formed by the pores as a starting point.

  In the present invention, the repeating unit is synonymous with the number average degree of polymerization.

  In the compound having at least one polymerizable group according to the present invention, examples of the polymerizable group include a vinyl group, an epoxy group, and an oxetane group. In the present invention, as a method of obtaining an organic molecule having 10 or less repeating units by polymerizing a compound having at least one polymerizable group, a monomer polymerization reaction is performed under polymerization conditions where the reaction is likely to stop. It can be easily obtained. For example, the polymerization initiator or catalyst concentration is controlled, a chain transfer agent or a polymerization terminator is used in combination, or the irradiation energy of ultraviolet rays, electrons, ions, heat, radical beams or radiation is controlled.

  Examples of the radical polymerization initiator used in the present invention include 2,2′-azobisbutyronitrile, 2,2′-azobiscyclohexanecarbonitrile, and 1,1′-azobis (cyclohexane-1-carbonitrile). 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) ), 4,4′-azobis (4-cyanovaleric acid), dimethyl 2,2′-azobisisobutyrate, 2,2′-azobis (2-methylpropionamidoxime), 2,2′-azobis (2- (2 -Imidazolin-2-yl) propane), azo initiators such as 2,2'-azobis (2,4,4-trimethylpentane), benzoyl peroxide, di-t-peroxide Peroxide initiators such as til, t-butyl hydroperoxide, cumene hydroperoxide, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, benzyl-β-methoxy Ethyl acetal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl Aromatics such as phenyl ketone, 4-phenoxydichloroacetophenone, 4-t-butyldichloroacetophenone, 4-t-butyltrichloroacetophenone, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one Carbonyl initiators Can be mentioned. Further, disulfide initiators such as tetraethylthiilam disulfide, nitroxyl initiators such as 2,2,6,6-tetramethylpiperidine-1-oxyl, 4,4′-di-t-butyl-2,2′- Living radical polymerization initiators such as a bipyridine copper complex-methyl trichloroacetate complex can also be used.

  Examples of the acid catalyst used in the present invention include clays such as activated clay and acid clay, mineral acids such as sulfuric acid and hydrochloric acid, organic acids such as p-toluenesulfonic acid and trifluoroacetic acid, aluminum chloride, ferric chloride, Lewis acids such as stannic chloride, titanium trichloride, titanium tetrachloride, boron trifluoride, hydrogen fluoride, boron tribromide, aluminum bromide, gallium chloride, gallium bromide, solid acids such as zeolite, Various materials such as silica, alumina, silica / alumina, cation exchange resin, heteropolyacid (for example, phosphotungstic acid, phosphomolybdic acid, silicotungstic acid, silicomolybdic acid) can be used.

Examples of the basic catalyst used in the present invention include alkali metal carbonates such as Li ₂ CO ₃ , Na ₂ CO ₃ and K ₂ CO ₃ , alkaline earth metal carbonates such as BaCO ₃ and CaCO ₃ , Li ₂ O, Alkali metal oxides such as Na ₂ O and K ₂ O, alkaline earth metal oxides such as BaO and CaO, alkali metals such as Na and K, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, or Examples thereof include alkoxides such as sodium, potassium, rubidium and cesium.

  In the present invention, the molecular weight of the oligomer produced can be controlled by the amount of polymerization initiator or catalyst used. That is, if the amount of the polymerization initiator or the catalyst used for the compound containing at least one polymerizable group as a monomer is increased, the molecular weight of the resulting oligomer is lowered. The amount of the polymerization initiator or catalyst used is in the range of 0.1 to 100% by mass, preferably 1 to 20% by mass, based on the compound having at least one polymerizable group.

  Examples of the chain transfer agent or polymerization terminator used in the present invention include acids such as hydrochloric acid, sulfuric acid and acetic acid, polyhalogenated methane, halogenated hydrocarbons, mercaptans, α-methylstyrene dimer, alcohols and other active hydrogen compounds, 2 2,2-disubstituted olefins such as 4-diphenyl-4-methyl-1-pentene and transition metal complexes such as cobalt complexes can be used. The amount of chain transfer agent or polymerization terminator used is preferably 0.01 to 0.5 molar ratio to the compound having at least one polymerizable group.

  Specific examples of the compound having at least one polymerizable group are given below, but the present invention is not limited thereto.

  When the compound having a polymerizable group or a reactive group according to the present invention is used, the conditions under which bonding is possible through a bond such as a covalent bond formed between the first layer and the second layer having different functions are as follows. It is important to arrange the materials, and for this purpose, compounds having a self-polymerizable group such as a vinyl group or an epoxy group are used as the compounds constituting each of the first layer and the second layer, or the first layer is used. It is preferable to apply a compound having a reactive group as in Group I below to the layer and a compound having a reactive group as in Group II below to the second layer.

Of the above combinations of reactive groups, preferred are those capable of addition reaction without generation of H ₂ O or the like.

  The compound having a polymerizable group or a reactive group according to the present invention is a compound in which single compounds can react to form a multimer, or two different compounds react with each other to form a covalent bond. Represents a possible compound. Preferred examples include compounds that do not undergo molecular elimination in the polymerization reaction, and particularly preferred are compounds having a functional group capable of radical polymerization such as a vinyl group, or compounds having a functional group capable of ring-opening polymerization such as an epoxy group. Can be mentioned. Most preferably, the compound which has a vinyl group is mentioned.

  The first compound and the second compound used in the present invention preferably have separate functions for the purpose of improving the performance of the device, and are exemplified as examples of a hole transport material, an electron transport material, and a light emitting layer described later. It is preferable to have each structure separately.

  As the first compound or the second compound, either a compound having an aromatic tertiary amine structure or a compound having an organometallic complex structure is preferable. More preferably, the first compound is a compound having an aromatic tertiary amine structure, and the second compound is a compound having an organometallic complex structure.

  Specific examples of the compound having a polymerizable group or a reactive group are given below, but the present invention is not limited thereto.

  Although the compound which concerns on this invention is contained as a main component in the at least 2 layer which comprises the organic EL element of this invention, you may contain another compound further.

  Next, the organic EL element of the present invention will be described.

  Examples of the contained compound include a fluorescent compound and a phosphorescent compound, and light emission derived from the contained fluorescent compound or phosphorescent compound can be obtained as light emission of the organic EL element. As the fluorescent compound, a compound having a high quantum yield used for a laser dye is preferable. In recent years, Princeton University has reported an organic EL device using phosphorescence emission from excited triplets (MA Baldo et al., Nature, 395, 151-154 (1998)), and excited singlet. In comparison with organic EL devices using fluorescent light from the light emission, the luminous efficiency is four times as much in principle and has been attracting attention. Also in the present invention, it is preferable to contain a phosphorescent compound from the viewpoint of luminous efficiency.

  Preferred as the fluorescent compound is one having a high fluorescence quantum yield in a solution state. Here, the fluorescence quantum yield is preferably 10% or more, particularly preferably 30% or more. Specific fluorescent compounds include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, stilbene dyes. System dyes, polythiophene dyes, rare earth complex phosphors, and the like. The fluorescence quantum yield here can be measured by the method described in Spectroscopic II, page 362 (1992 edition, Maruzen) of 4th edition Experimental Chemistry Course 7.

  The phosphorescent compound in the present invention is a compound in which light emission from an excited triplet is observed, and is a compound having a phosphorescence quantum yield of 0.001 or more at 25 ° C. The phosphorescent quantum yield is preferably 0.01 or more, more preferably 0.1 or more. The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of the Fourth Edition Experimental Chemistry Course 7. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence quantum yield used in the present invention is only required to achieve the above phosphorescence quantum yield in any solvent.

  The phosphorescent compound used in the present invention is preferably a complex compound containing a group VIII metal in the periodic table of elements, more preferably an iridium compound, an osmium compound, or a platinum compound (platinum complex compound). Of these, iridium compounds are most preferred.

  Specific examples of the phosphorescent compound used in the present invention are shown below, but are not limited thereto. These compounds are described, for example, in Inorg. Chem. 40, 1704-1711, and the like. In addition, the fluorescent compound and phosphorescent compound to be contained may or may not have a polymerizable group or a reactive group.

<< Layer structure of organic electroluminescence element >>
The layer structure of the organic electroluminescence element (organic EL element) according to the present invention will be described.

  In a broad sense, the light emitting layer according to the present invention is a layer that emits light when a current is passed through an electrode composed of a cathode and an anode. Specifically, when a current is passed through an electrode composed of a cathode and an anode, A layer containing a compound that emits light.

  The organic EL device of the present invention has a structure in which a hole transport layer, an electron transport layer, an anode buffer layer, a cathode buffer layer, and the like are provided in addition to the light emitting layer as needed, and are sandwiched between a cathode and an anode. Specific examples include the structures shown below.

(I) Anode / hole transport layer / light emitting layer / cathode (ii) Anode / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iv) Anode / Anode buffer layer / hole transport layer / light emitting layer / electron transport layer / cathode buffer layer / cathode At least two adjacent layers among a plurality of layers sandwiched between electrodes (anode and cathode) constituting the organic EL element However, it is preferable to be constituted by a layer containing the first compound according to the present invention and a layer containing the second compound according to the present invention. Furthermore, it is preferable to have three or more organic layers between the cathode and the anode.

<Light emitting layer>
The light emitting layer according to the organic EL device of the present invention will be described. The light emitting layer is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and the light emitting portion is adjacent to the light emitting layer even in the layer of the light emitting layer. It may be an interface with the layer.

  The material used for the light emitting layer (hereinafter referred to as the light emitting material) is preferably an organic compound or complex that emits fluorescence or phosphorescence, and is appropriately selected from known materials used for the light emitting layer of the organic EL device. Can be used. Such a light-emitting material is mainly an organic compound. Synth. 125, pages 17-25, and the like.

  The light emitting material may have a hole transporting function and an electron transporting function in addition to the light emitting performance, and most of the hole transporting material and the electron transporting material can be used as the light emitting material. The light emitting material may be a polymer material such as p-polyphenylene vinylene or polyfluorene, and further using a polymer material in which the light emitting material is introduced into a polymer chain or the light emitting material is a polymer main chain. Also good.

  In general, the light emitting layer is preferably disposed on the cathode side of the hole transport layer from the viewpoint of the performance of the device. Therefore, compared with the hole transport material, all the materials used for the light emitting layer are relatively (of the present invention). By definition) becomes an electron transport material.

(Film thickness of the light emitting layer)
There is no restriction | limiting in particular about the film thickness of the light emitting layer formed in this way, Although it can select suitably according to a condition, It is preferable to adjust film thickness in the range of 5 nm-5 micrometers.

  Next, other layers constituting the organic EL element in combination with the light emitting layer, such as a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer, will be described.

<< Hole injection layer, hole transport layer, electron injection layer, electron transport layer >>
The hole injection layer and hole transport layer used in the present invention have a function of transmitting holes injected from the anode to the light emitting layer. The hole injection layer and hole transport layer are formed of an anode and a light emitting layer. By interposing them, many holes are injected into the light emitting layer with a lower electric field, and electrons injected into the light emitting layer from the cathode, electron injection layer, or electron transport layer are injected into the light emitting layer and holes. Due to an electron barrier existing at the interface of the layer or the hole transport layer, it is accumulated at the interface in the light emitting layer, and the light emitting efficiency is improved.

《Hole injection material, hole transport material》
The material of the hole injection layer and hole transport layer (hereinafter referred to as hole injection material and hole transport material) has the property of transmitting holes injected from the anode to the light emitting layer. If it is a thing, there will be no restriction | limiting in particular, In a photoconductive material, what is conventionally used as a charge injection transport material of a hole, and well-known used for the hole injection layer of a EL element, a hole transport layer Any one can be selected and used.

  The hole injection material and the hole transport material have either hole injection or transport or electron barrier properties, and may be either organic or inorganic. Examples of the hole injection material and hole transport material include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, An oxazole derivative, a styryl anthracene derivative, a fluorenone derivative, a hydrazone derivative, a stilbene derivative, a silazane derivative, an aniline-based copolymer, or a conductive polymer oligomer, particularly a thiophene oligomer can be used.

  The above-mentioned materials can be used as the hole injection material and the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound. .

  Representative examples of the aromatic tertiary amine compound and styrylamine compound include N, N, N ′, N′-tetraphenyl-4,4′-diaminophenyl; N, N′-diphenyl-N, N ′. -Bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 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) quadri N; N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenyl Amino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and two more described in US Pat. No. 5,061,569 Having a condensed aromatic ring of, for example, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD), JP-A-4-30 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 8688 are linked in a starburst type ( MTDATA) etc. Further, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  Alternatively, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material. The hole injection layer and the hole transport layer are formed by thinning the hole injection material and the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, or an LB method. Can be formed.

(Hole injection layer thickness, hole transport layer thickness)
Although there is no restriction | limiting in particular about the film thickness of a positive hole injection layer and a positive hole transport layer, It is preferable to prepare in the range of about 5 nm-5 micrometers. The hole injection layer and hole transport layer may have a single layer structure composed of one or more of the above materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

<< Electron transport layer, electron transport material >>
The electron transport layer according to the present invention is only required to have a function of transmitting electrons injected from the cathode to the light emitting layer, and as the material thereof, any one of conventionally known compounds can be selected and used. Can do.

  Examples of materials used for this electron transport layer (hereinafter referred to as electron transport materials) include heterocyclic tetracarboxylic acid anhydrides such as nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, naphthalene perylene, carbodiimides, Examples include fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, and organometallic complexes. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  Or metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum , Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like, and the central metal of these metal complexes is In, Mg, Metal complexes replaced with Cu, Ca, Sn, Ga or Pb can also be used as the electron transport material.

  In addition, metal-free or metal phthalocyanine, and those in which the terminal is substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transport material. Alternatively, the distyrylpyrazine derivative exemplified as the material for the light-emitting layer can also be used as an electron transport material, and inorganic semiconductors such as n-type-Si and n-type-SiC can be used as well as the hole injection layer and the hole transport layer. It can be used as an electron transport material.

(Film thickness of electron transport layer)
Although the film thickness of an electron carrying layer does not have a restriction | limiting in particular, It is preferable to prepare in the range of 5 nm-5 micrometers. This electron transport layer may have a single layer structure composed of one or two or more of these electron transport materials, or may have a laminated structure composed of a plurality of layers having the same composition or different compositions.

  In the present invention, the fluorescent compound is not limited to the light emitting layer alone, and is the same region as the fluorescent compound that becomes the host compound of the phosphorescent compound in the hole transport layer adjacent to the light emitting layer or the electron transport layer. May contain at least one fluorescent compound having a fluorescent maximum wavelength, thereby further improving the luminous efficiency of the EL element. As the fluorescent compound contained in these hole transport layer and electron transport layer, the fluorescent compound having a fluorescence maximum wavelength in the range of 350 to 440 nm, more preferably 390 to 410 nm, as in the light emitting layer. A compound is used.

  Next, a suitable example for producing the organic EL element will be described. As an example, a method for manufacturing an EL element composed of the anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode will be described.

  First, a thin film made of a desired electrode material, for example, an anode material, is formed on a suitable substrate by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 to 200 nm. Is made. Next, a thin film comprising a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer / electron injection layer, which is a device material, is formed thereon. Further, a buffer layer (electrode interface layer) may be present between the anode and the light emitting layer or hole injection layer and between the cathode and the light emitting layer or electron injection layer.

  The buffer layer is a layer provided between the electrode and the organic layer in order to lower the driving voltage and improve the luminous efficiency. “The organic EL element and its forefront of industrialization (published by NTS Corporation on November 30, 1998) 2), Chapter 2, “Electrode Materials” (pages 123 to 166) in detail, and includes an anode buffer layer and a cathode buffer layer.

  The details of the anode buffer layer are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. Specific examples include a phthalocyanine buffer layer represented by copper phthalocyanine, Examples thereof include an oxide buffer layer typified by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

  The details of the cathode buffer layer are described in JP-A-6-325871, JP-A-9-17574, and JP-A-10-74586, and specifically, metal buffers represented by strontium, aluminum and the like. Examples thereof include an alkali metal compound buffer layer typified by lithium fluoride, an alkaline earth metal compound buffer layer typified by magnesium fluoride, an oxide buffer layer typified by aluminum oxide and lithium oxide, and the like.

  The buffer layer is preferably a very thin film, and the film thickness is preferably in the range of 0.1 to 100 nm, although it depends on the material.

  Further, in addition to the above basic constituent layers, layers having other functions may be laminated as required. For example, JP-A-11-204258, JP-A-11-204359, and “Organic EL element and its It may have a functional layer such as a hole blocking layer described on page 237 of “Industrialization Front Line (November 30, 1998, issued by NTT)”.

"electrode"
Next, the electrode of the organic EL element will be described. The electrode of the organic EL element consists of a cathode and an anode. As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO.

  The anode may be formed by depositing a thin film of these electrode materials by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or the pattern accuracy is not required so much (about 100 μm or more) ) May form a pattern through a mask having a desired shape during vapor deposition or sputtering of the electrode material. When light emission is extracted from the anode, it is desirable that the transmittance is greater than 10%, or the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 nm to 1 μm, preferably 10 to 200 nm.

On the other hand, as the cathode, those having an electrode substance of a metal having a low work function (4 eV or less) (referred to as an electron injecting metal), an alloy, an electrically conductive compound and a mixture thereof are preferably used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the viewpoint of electron injecting property and durability against oxidation, a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function value than this, for example, a magnesium / silver mixture, magnesium / Aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures and the like are preferred.

  The cathode can be produced by forming a thin film from these electrode materials by a method such as vapor deposition or sputtering. Alternatively, the sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 1 μm, preferably 50 to 200 nm. In addition, in order to transmit light emission, if either one of the anode or the cathode of the organic EL element is transparent or translucent, it is advantageous because the light emission efficiency is improved.

<Display device>
The organic EL device of the present invention may be used as a kind of lamp such as an illumination or exposure light source, a projection device that projects an image, or a display device that directly recognizes a still image or a moving image. (Display) may be used. The driving method when used as a display device for moving image reproduction may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, a full-color display device can be manufactured by using two or more organic EL elements of the present invention having different emission colors.

《Light extraction technology》
In order to improve the light extraction efficiency of the light emitted from the light emitting layer, the organic EL device of the present invention performs prism-like or lens-like processing on the surface of the substrate, or attaches a prism sheet or lens sheet to the surface of the substrate. May be.

  The organic EL device of the present invention may have a low refractive index layer between the transparent electrode and the transparent substrate. Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer.

  Since the refractive index of the transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Furthermore, it is preferable that it is 1.35 or less. The thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low refractive index layer is diminished when the thickness of the low refractive index medium is about the wavelength of light and the electromagnetic wave that has exuded by evanescent enters the substrate.

  The organic EL element of the present invention may have a diffraction grating in any layer or in a medium (in a transparent substrate or a transparent electrode). It is desirable that the diffraction grating to be introduced has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. Therefore, the light extraction efficiency does not increase so much. However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased. As described above, the position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or the transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated. At this time, the period of the diffraction grating is preferably about 1/2 to 3 times the wavelength of light in the medium. The arrangement of the diffraction gratings is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

《Gas barrier layer》
The composition of the gas barrier layer according to the present invention is not particularly limited as long as it is a layer that blocks permeation of oxygen and water vapor. Specifically, an inorganic oxide is preferable as the material constituting the gas barrier layer according to the present invention, and examples include silicon oxide, aluminum oxide, silicon oxynitride, aluminum oxynitride, magnesium oxide, zinc oxide, indium oxide, and tin oxide. be able to.

  The thickness of the gas barrier layer in the present invention is appropriately selected depending on the type and configuration of the material used, and is suitably selected, but is preferably in the range of 5 to 2000 nm. This is because when the thickness of the gas barrier layer is thinner than the above range, a uniform film cannot be obtained, and it is difficult to obtain a barrier property against gas. Further, when the thickness of the gas barrier layer is larger than the above range, it is difficult to maintain the flexibility of the gas barrier film, and the gas barrier film is cracked due to external factors such as bending and pulling after film formation. This is because it may occur.

  For the gas barrier layer according to the present invention, a raw material described later is applied by a spray method, a spin coating method, a sputtering method, an ion assist method, a plasma CVD method described later, a plasma CVD method under atmospheric pressure or a pressure near atmospheric pressure described later, and the like. Can be formed.

  However, in wet methods such as spraying and spin coating, it is difficult to obtain smoothness at the molecular level (nm level), and since a solvent is used, the substrate described later is an organic material, so it can be used. Has the disadvantage that limited substrates or solvents are limited. Therefore, in the present invention, it is preferable that the film is formed by a plasma CVD method or the like. In particular, the atmospheric pressure plasma CVD method does not require a decompression chamber or the like, and can be formed at high speed and has high productivity. It is preferable from the point. This is because, by forming the gas barrier layer by an atmospheric pressure plasma CVD method, a film having a uniform and smooth surface can be formed relatively easily.

  The plasma CVD method is a plasma CVD method under atmospheric pressure or a pressure near atmospheric pressure, and is particularly preferably formed using a plasma CVD method under atmospheric pressure or a pressure near atmospheric pressure. Details of the layer formation conditions of the plasma CVD method will be described later.

  The gas barrier layer obtained by the plasma CVD method, or the plasma CVD method under atmospheric pressure or near atmospheric pressure, selects the conditions such as the organometallic compound, decomposition gas, decomposition temperature, and input power that are raw materials (also referred to as raw materials) Therefore, metal carbides, metal nitrides, metal oxides, metal sulfides, metal halides, and mixtures thereof (metal oxynitrides, metal oxide halides, metal nitride carbides, etc.) can be formed separately, which is preferable. .

  For example, when a silicon compound is used as a raw material compound and oxygen is used as a decomposition gas, silicon oxide is generated. Moreover, if a zinc compound is used as a raw material compound and carbon disulfide is used as the cracking gas, zinc sulfide is generated. This is because highly active charged particles and active radicals exist in the plasma space at a high density, so that multistage chemical reactions are accelerated at high speed in the plasma space, and the elements present in the plasma space are thermodynamic. This is because it is converted into an extremely stable compound in a very short time.

  As such an inorganic material, as long as it has a typical or transition metal element, it may be in a gas, liquid, or solid state at normal temperature and pressure. In the case of gas, it can be introduced into the discharge space as it is, but in the case of liquid or solid, it is used after being vaporized by means such as heating, bubbling, decompression or ultrasonic irradiation. Moreover, you may dilute and use with a solvent and the solvent can use organic solvents, such as methanol, ethanol, n-hexane, and these mixed solvents. In addition, since these dilution solvents are decomposed | disassembled into molecular form and atomic form during plasma discharge processing, the influence can be disregarded almost.

  Examples of such organometallic compounds include silicon compounds such as silane, tetramethoxysilane, tetraethoxysilane, tetra n-propoxysilane, tetraisopropoxysilane, tetra n-butoxysilane, tetrat-butoxysilane, dimethyldimethoxysilane, and dimethyl. Diethoxysilane, diethyldimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, phenyltriethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, hexamethyldisiloxane, bis (dimethyl Amino) dimethylsilane, bis (dimethylamino) methylvinylsilane, bis (ethylamino) dimethylsilane, N, O-bis (trimethylsilyl) acetamide, bis (trimethylsilyl) carbonate Bodiimide, diethylaminotrimethylsilane, dimethylaminodimethylsilane, hexamethyldisilazane, hexamethylcyclotrisilazane, heptamethyldisilazane, nonamethyltrisilazane, octamethylcyclotetrasilazane, tetrakisdimethylaminosilane, tetraisocyanatosilane, tetramethyldi Silazane, tris (dimethylamino) silane, triethoxyfluorosilane, allyldimethylsilane, allyltrimethylsilane, benzyltrimethylsilane, bis (trimethylsilyl) acetylene, 1,4-bistrimethylsilyl-1,3-butadiyne, di-t-butylsilane 1,3-disilabutane, bis (trimethylsilyl) methane, cyclopentadienyltrimethylsilane, phenyldimethylsilane, phenyltri Tylsilane, propargyltrimethylsilane, tetramethylsilane, trimethylsilylacetylene, 1- (trimethylsilyl) -1-propyne, tris (trimethylsilyl) methane, tris (trimethylsilyl) silane, vinyltrimethylsilane, hexamethyldisilane, octamethylcyclotetrasiloxane, tetra Examples include methylcyclotetrasiloxane, hexamethylcyclotetrasiloxane, and M silicate 51.

  Examples of the titanium compound include titanium methoxide, titanium ethoxide, titanium isopropoxide, titanium tetraisoporooxide, titanium n-butoxide, titanium diisopropoxide (bis-2,4-pentanedionate), titanium. Examples thereof include diisopropoxide (bis-2,4-ethylacetoacetate), titanium di-n-butoxide (bis-2,4-pentanedionate), titanium acetylacetonate, and butyl titanate dimer.

  Zirconium compounds include zirconium n-propoxide, zirconium n-butoxide, zirconium t-butoxide, zirconium tri-n-butoxide acetylacetonate, zirconium di-n-butoxide bisacetylacetonate, zirconium acetylacetonate, zirconium acetate, Zirconium hexafluoropentanedioate and the like can be mentioned.

  Examples of the aluminum compound include aluminum ethoxide, aluminum triisopropoxide, aluminum isopropoxide, aluminum n-butoxide, aluminum s-butoxide, aluminum t-butoxide, aluminum acetylacetonate, and triethyldialuminum tri-s-butoxide. Can be mentioned.

  The boron compounds include diborane, tetraborane, boron fluoride, boron chloride, boron bromide, borane-diethyl ether complex, borane-THF complex, borane-dimethyl sulfide complex, boron trifluoride diethyl ether complex, triethylborane, trimethoxy. Examples include borane, triethoxyborane, tri (isopropoxy) borane, borazole, trimethylborazole, triethylborazole, triisopropylborazole, and the like.

  Examples of tin compounds include tetraethyltin, tetramethyltin, di-n-butyltin diacetate, tetrabutyltin, tetraoctyltin, tetraethoxytin, methyltriethoxytin, diethyldiethoxytin, triisopropylethoxytin, diethyltin, Dimethyltin, diisopropyltin, dibutyltin, diethoxytin, dimethoxytin, diisopropoxytin, dibutoxytin, tin dibutyrate, tin diacetoacetonate, ethyltin acetoacetonate, ethoxytin acetoacetonate, dimethyltin diacetoacetonate Examples of tin halides such as tin hydrogen compounds include tin dichloride and tin tetrachloride.

  Other organometallic compounds include, for example, antimony ethoxide, arsenic triethoxide, barium 2,2,6,6-tetramethylheptanedionate, beryllium acetylacetonate, bismuth hexafluoropentanedionate, dimethylcadmium, calcium 2 , 2,6,6-tetramethylheptanedionate, chromium trifluoropentanedionate, cobalt acetylacetonate, copper hexafluoropentanedionate, magnesium hexafluoropentanedionate-dimethyl ether complex, gallium ethoxide, tetraethoxygermane, Tetramethoxygermane, hafnium t-butoxide, hafnium ethoxide, indium acetylacetonate, indium 2,6-dimethylaminoheptanedionate, Erocene, lanthanum isopropoxide, lead acetate, tetraethyllead, neodymium acetylacetonate, platinum hexafluoropentanedionate, trimethylcyclopentadienylplatinum, rhodium dicarbonylacetylacetonate, strontium 2,2,6,6-tetramethyl Examples include heptanedionate, tantalum methoxide, tantalum trifluoroethoxide, tellurium ethoxide, tungsten ethoxide, vanadium triisopropoxide oxide, magnesium hexafluoroacetylacetonate, zinc acetylacetonate, and diethylzinc.

  In addition, as a decomposition gas for decomposing a raw material gas containing these metals to obtain an inorganic compound, hydrogen gas, methane gas, acetylene gas, carbon monoxide gas, carbon dioxide gas, nitrogen gas, ammonia gas, nitrous oxide Examples include gas, nitrogen oxide gas, nitrogen dioxide gas, oxygen gas, water vapor, fluorine gas, hydrogen fluoride, trifluoroalcohol, trifluorotoluene, hydrogen sulfide, sulfur dioxide, carbon disulfide, and chlorine gas.

  Various metal carbides, metal nitrides, metal oxides, metal halides, and metal sulfides can be obtained by appropriately selecting a source gas containing a metal element and a decomposition gas.

  A discharge gas that tends to be in a plasma state is mixed with these reactive gases, and the gas is sent to the plasma discharge generator. As such a discharge gas, nitrogen gas and / or 18th group atom of the periodic table, specifically helium, neon, argon, krypton, xenon, radon, etc. are used. Among these, nitrogen, helium, and argon are preferably used.

  The discharge gas and the reactive gas are mixed, and a film is formed by supplying the mixed gas as a mixed gas to a plasma discharge generator (plasma generator). The ratio of the discharge gas and the reactive gas varies depending on the properties of the film to be obtained, but the reactive gas is supplied with the ratio of the discharge gas to 50% or more of the entire mixed gas.

  FIG. 2 is a schematic view showing an example of an atmospheric pressure plasma discharge treatment apparatus that treats a substrate between counter electrodes useful for the present invention.

  The atmospheric pressure plasma discharge processing apparatus according to the present invention is an apparatus having at least a plasma discharge processing apparatus 30, an electric field applying means 40 having two power supplies, a gas supply means 50, and an electrode temperature adjusting means 60.

  FIG. 2 shows a thin film formed by subjecting the base material F to plasma discharge treatment between the counter electrodes (discharge space) 32 between the roll rotating electrode (first electrode) 35 and the square tube type fixed electrode group (second electrode) 36. Is. In FIG. 2, one electric field is formed by a pair of rectangular tube type fixed electrode group (second electrode) 36 and roll rotating electrode (first electrode) 35, and this one unit, for example, a low density layer Form. FIG. 2 shows a configuration example in which a total of five units having such a configuration are provided. By arbitrarily independently controlling the type of raw material supplied by each unit, the output voltage, etc., the present invention It is possible to continuously form a laminated transparent gas barrier layer having a configuration defined in (1).

In the discharge space (between the counter electrodes) 32 between the roll rotating electrode (first electrode) 35 and the square tube type fixed electrode group (second electrode) 36, the roll rotating electrode (first electrode) 35 has a first power source. 41 to the first high-frequency electric field of frequency ω ₁ , electric field strength V ₁ , and current I ₁ , and to the rectangular tube-shaped fixed electrode group (second electrode) 36, the frequency ω ₂ from each second power source 42 corresponding thereto. A second high frequency electric field of electric field strength V ₂ and current I ₂ is applied.

  A first filter 43 is installed between the roll rotation electrode (first electrode) 35 and the first power supply 41, and the first filter 43 easily passes a current from the first power supply 41 to the first electrode. The current from the second power supply 42 is grounded so that the current from the second power supply 42 to the first power supply is difficult to pass. In addition, a second filter 44 is installed between the square tube type fixed electrode group (second electrode) 36 and the second power source 42, and the second filter 44 is connected from the second power source 42 to the second electrode. It is designed to facilitate the passage of current, ground the current from the first power supply 41, and make it difficult to pass the current from the first power supply 41 to the second power supply.

In the present invention, the roll rotation electrode 35 may be the second electrode, and the square tube type fixed electrode group 36 may be the first electrode. In any case, the first power source is connected to the first electrode, and the second power source is connected to the second electrode. The first power supply preferably applies a higher frequency electric field strength (V ₁ > V ₂ ) than the second power supply. The frequency has the ability to satisfy ω ₁ <ω ₂ .

The current is preferably I ₁ <I ₂ . The current I ₁ of the first high-frequency electric field is preferably 0.3 to 20 mA / cm ² , more preferably 1.0 to 20 mA / cm ² . The current I ₂ of the second high frequency electric field is preferably 10 to 100 mA / cm ² , more preferably 20 to 100 mA / cm ² .

  The gas G generated by the gas generator 51 of the gas supply means 50 is introduced into the plasma discharge processing vessel 31 from the air supply port while controlling the flow rate.

  The base material F is unwound from the original winding (not shown) and is transported, or transported from the previous process, and the air and the like that is entrained by the base material by the nip roll 65 through the guide roll 64 is cut off. While being in contact with the roll rotating electrode 35, it is transferred between the square tube fixed electrode group 36 and the roll rotating electrode (first electrode) 35 and the square tube fixed electrode group (second electrode) 36. An electric field is applied from both sides to generate discharge plasma between the counter electrodes (discharge space) 32. The base material F forms a thin film with a gas in a plasma state while being wound while being in contact with the roll rotating electrode 35. The base material F passes through the nip roll 66 and the guide roll 67 and is wound up by a winder (not shown) or transferred to the next process.

  Discharged treated exhaust gas G ′ is discharged from the exhaust port 53.

  In order to heat or cool the roll rotating electrode (first electrode) 35 and the rectangular tube type fixed electrode group (second electrode) 36 during the formation of the thin film, a medium whose temperature is adjusted by the electrode temperature adjusting means 60 is used as a liquid feed pump. P is sent to both electrodes through the pipe 61, and the temperature is adjusted from the inside of the electrode. Reference numerals 68 and 69 denote partition plates that partition the plasma discharge processing vessel 31 from the outside.

In the gas barrier layer according to the present invention, the inorganic compound contained in the gas barrier layer is preferably SiO _x , SiN _y or SiO _x N _y (x = 1 to 2, y = 0 to 1), particularly From the viewpoint of moisture permeability, light transmittance and suitability for atmospheric pressure plasma CVD described later, SiO _x is preferable.

The inorganic compound according to the present invention can obtain, for example, a film containing at least one of O atoms and N atoms and Si atoms by further combining oxygen gas or nitrogen gas with the above-mentioned organosilicon compound at a predetermined ratio. Although SiO ₂ is highly transparent, it has a slightly lower gas barrier property and allows water to pass therethrough, so it is more preferable that it contains N atoms. That is, when the ratio of the number of oxygen atoms and nitrogen atoms is x: y, x / (x + y) is 0.95 or less, more preferably 0.80 or less. Therefore, in the gas barrier layer according to the present invention, the light transmittance T is preferably 80% or more.

  In addition, when there are many ratios of N atom, light transmittance will fall and SiN which is x = 0 will show a little yellowishness. Therefore, a specific ratio of oxygen atoms and nitrogen atoms may be determined according to the application. For example, in an application that requires light transmission, such as when a film is formed on the light emitting surface side of a light emitting element in a display device, if x / (x + y) is 0.4 or more and 0.95, It is preferable because a balance between light transmittance and waterproofness can be achieved. In addition, if it is preferable to absorb or block light like a reflection preventing film provided on the rear surface of the light emitting element of the display device, x / (x + y) is preferably 0 or more and less than 0.4. .

  Therefore, the gas barrier layer according to the present invention is preferably transparent. This is because when the gas barrier layer is transparent, the gas barrier film can be made transparent, and can be used for applications such as a transparent substrate of an organic EL element.

  FIG. 1 is a schematic diagram showing an example of a layer configuration and a density profile of a transparent gas barrier film according to the present invention.

  The transparent gas barrier film 1 according to the present invention has a configuration in which layers having different densities are laminated on a substrate 2. The present invention is characterized in that the medium density layer 4 according to the present invention is provided between the low density layer 3 and the high density layer 5, and further, the medium density layer 4 is provided on the high density layer. A configuration including a low density layer, a medium density layer, a high density layer, and a medium density layer is one unit, and FIG. 1 shows an example in which two units are stacked. At this time, the density distribution in each density layer is uniform, and the density change between adjacent layers is stepped. In FIG. 1, the medium density layer 4 is shown as one layer, but it may have a configuration of two or more layers as necessary.

"substrate"
The substrate used in the transparent gas barrier film according to the present invention is not particularly limited as long as it is a film formed of an organic material capable of holding the above-described gas barrier layer having a barrier property.

  Specifically, homopolymers or copolymers such as ethylene, polypropylene and butene, polyolefin (PO) resins such as copolymers, amorphous polyolefin resins (APO) such as cyclic polyolefins, polyethylene terephthalate (PET), Polyester resins such as polyethylene 2,6-naphthalate (PEN), polyamide (PA) resins such as nylon 6, nylon 12, copolymer nylon, polyvinyl alcohol (PVA) resin, ethylene-vinyl alcohol copolymer (EVOH) Polyvinyl alcohol resins such as polyimide (PI) resin, polyetherimide (PEI) resin, polysulfone (PS) resin, polyethersulfone (PES) resin, polyetheretherketone (PEEK) resin, polycarbonate (PC) resin , Polyvini Butyrate (PVB) resin, polyarylate (PAR) resin, ethylene-tetrafluoroethylene copolymer (ETFE), ethylene trifluoride chloride (PFA), ethylene tetrafluoride-perfluoroalkyl vinyl ether copolymer (FEP) Fluorine-based resins such as vinylidene fluoride (PVDF), vinyl fluoride (PVF), and perfluoroethylene-perfluoropropylene-perfluorovinyl ether-copolymer (EPA) can be used.

  In addition to the resins listed above, a resin composition comprising an acrylate compound having a radical-reactive unsaturated compound, a resin composition comprising a mercapto compound having an acrylate compound and a thiol group, epoxy acrylate, urethane acrylate It is also possible to use a photocurable resin such as a resin composition in which an oligomer such as polyester acrylate or polyether acrylate is dissolved in a polyfunctional acrylate monomer, and a mixture thereof. Furthermore, it is also possible to use as a substrate film a laminate of one or more of these resins by means such as laminating or coating.

  These materials can be used alone or in combination as appropriate. Among them, ZEONEX and ZEONOR (manufactured by ZEON CORPORATION), amorphous cyclopolyolefin resin film ARTON (manufactured by JSR Corporation), polycarbonate film Pure Ace (manufactured by Teijin Limited), Konicatac of cellulose triacetate film Commercial products such as KC4UX and KC8UX (manufactured by Konica Minolta Opto Co., Ltd.) can be preferably used.

  The substrate is preferably transparent. This is because the substrate is transparent and the layer formed on the substrate is also transparent, so that a transparent gas barrier film can be obtained, and thus a transparent substrate such as an organic EL element can be obtained. .

  Moreover, the unstretched film may be sufficient as the board | substrate which concerns on this invention using resin etc. which were mentioned above, and a stretched film may be sufficient as it.

  The substrate according to the present invention can be manufactured by a conventionally known general method. For example, an unstretched substrate that is substantially amorphous and not oriented can be produced by melting a resin as a material with an extruder, extruding it with an annular die or a T-die, and quenching. In addition, the unstretched base material is subjected to a known method such as uniaxial stretching, tenter-type sequential biaxial stretching, tenter-type simultaneous biaxial stretching, tubular-type simultaneous biaxial stretching, or the flow direction of the base material (vertical axis), or A stretched substrate can be produced by stretching in the direction perpendicular to the flow direction of the substrate (horizontal axis). Although the draw ratio in this case can be suitably selected according to the resin used as the raw material of the base material, it is preferably 2 to 10 times in the vertical axis direction and the horizontal axis direction.

  In addition, the substrate according to the present invention may be subjected to surface treatment such as corona treatment, flame treatment, plasma treatment, glow discharge treatment, roughening treatment, and chemical treatment before forming the vapor deposition film.

Furthermore, you may form an anchor coating agent layer in the base-material surface based on this invention for the purpose of the adhesive improvement with a vapor deposition film. Examples of the anchor coating agent used in this anchor coating agent layer include polyester resin, isocyanate resin, urethane resin, acrylic resin, ethylene vinyl alcohol resin, vinyl modified resin, epoxy resin, modified styrene resin, modified silicon resin, and alkyl titanate. Can be used alone or in combination. Conventionally known additives can be added to these anchor coating agents. The above-mentioned anchor coating agent is coated on the substrate by a known method such as roll coating, gravure coating, knife coating, dip coating, spray coating, etc., and anchor coating is performed by drying and removing the solvent, diluent, etc. Can do. The application amount of the anchor coating agent is preferably about 0.1 to 5 g / m ² (dry state).

  The substrate is conveniently a long product rolled up. Since the thickness of the substrate varies depending on the use of the obtained gas barrier film, it cannot be specified unconditionally. However, when the gas barrier film is used for packaging, there is no particular limitation, and due to its suitability as a packaging material, 3 ˜400 μm, preferably 6-30 μm.

  Moreover, as for the film thickness of the board | substrate used for this invention, 10-200 micrometers is preferable, More preferably, it is 50-100 micrometers.

As the water vapor permeability of the gas barrier film according to the present invention, the water vapor permeability measured according to the JIS K7129 B method when used for applications requiring high water vapor barrier properties such as organic EL displays and high-definition color liquid crystal displays. 1.0 g / m ² / day or less, and in the case of an organic EL display application, a dark spot that grows even if it is very small may occur, and the display life of the display may be extremely shortened. Therefore, the water vapor permeability is preferably less than 0.1 g / m ² / day.

  Hereinafter, although an example explains the present invention, the present invention is not limited to this.

Example 1
<Preparation of organic EL element OLED1-1>
As a substrate, on a polyethylene terephthalate film having a thickness of 100 μm (a film made by Teijin-Dyupon Co., Ltd., hereinafter abbreviated as PEN), a low-density layer having a profile configuration shown in FIG. A transparent gas barrier film in which three layers of a medium density layer, a high density layer, and a medium density layer were laminated was produced.

(Atmospheric pressure plasma discharge treatment equipment)
Using the atmospheric pressure plasma discharge treatment apparatus of FIG. 2, a set of a roll electrode covered with a dielectric and a plurality of rectangular tube electrodes was produced as follows.

  The roll electrode serving as the first electrode is coated with a high-density, high-adhesion alumina sprayed film by an atmospheric plasma method on a jacket roll metallic base material made of titanium alloy T64 having cooling means by cooling water, and roll diameter It was set to 1000 mmφ. On the other hand, the square electrode of the second electrode is a hollow rectangular tube-shaped titanium alloy T64 covered with 1 mm of the same dielectric material with the same thickness under the same conditions, and the opposing rectangular tube-shaped fixed electrode group and did.

Twenty-four square tube electrodes were arranged around the roll rotating electrode with a counter electrode gap of 1 mm. The total discharge area of the square tube type fixed electrode group was 150 cm (length in the width direction) × 4 cm (length in the transport direction) × 24 (number of electrodes) = 14400 cm ² . In all cases, appropriate filters were installed.

  During plasma discharge, the first electrode (roll rotating electrode) and the second electrode (square tube fixed electrode group) were adjusted and kept at 80 ° C., and the roll rotating electrode was rotated by a drive to form a thin film. Among the 24 rectangular tube-type fixed electrodes, 4 from the upstream side are used for forming the following first layer (low density layer 1), and the following 6 are used for forming the following second layer (medium density layer 1). For the film, the following 8 pieces are used for forming the third layer (high density layer 1) and the remaining 6 pieces are used for forming the fourth layer (medium density layer 2). 4 layers were stacked in one pass. This condition was further repeated twice to produce a transparent gas barrier film 1.

(First layer: low density layer 1)
Plasma discharge was performed under the following conditions to form a low density layer 1 having a thickness of about 90 nm.

<Gas conditions>
Discharge gas: Nitrogen gas 94.8% by volume
Thin film forming gas: Hexamethyldisiloxane (mixed with nitrogen gas in a vaporizer manufactured by Lintec Corporation and vaporized) 0.2% by volume
Additive gas: Oxygen gas 5.0% by volume
<Power supply conditions: Only the power supply on the first electrode side was used>
1st electrode side Power supply type
Frequency 80kHz
Output density 10W / cm ²
The density of the formed first layer (low density layer) was 1.90 as a result of measurement by the X-ray reflectivity method using MXP21 manufactured by MacScience.

(Second layer: Medium density layer 1)
Plasma discharge was performed under the following conditions to form a medium density layer 1 having a thickness of about 90 nm.

<Gas conditions>
Discharge gas: Nitrogen gas 94.9% by volume
Thin film forming gas: Hexamethyldisiloxane (vaporized by mixing with nitrogen gas using a vaporizer manufactured by Lintec) 0.1% by volume
Additive gas: Oxygen gas 5.0% by volume
<Power supply conditions: Only the power supply on the first electrode side was used>
1st electrode side Power supply type
Frequency 80kHz
Output density 10W / cm ²
The density of the formed second layer (medium density layer) was 2.05 as a result of measurement by the X-ray reflectivity method using MXP21 manufactured by MacScience.

(Third layer: High-density layer 1)
Plasma discharge was performed under the following conditions to form a high-density layer 1 having a thickness of about 90 nm.

<Gas conditions>
Discharge gas: Nitrogen gas 94.9% by volume
Thin film forming gas: Hexamethyldisiloxane (vaporized by mixing with nitrogen gas using a vaporizer manufactured by Lintec) 0.1% by volume
Additive gas: Oxygen gas 5.0% by volume
<Power supply conditions>
1st electrode side Power supply type
Frequency 80kHz
Output density 10W / cm ²
Second electrode side Power supply type High frequency power supply manufactured by Pearl Industrial Co., Ltd.
Frequency 13.56MHz
Output density 10W / cm ²
The density of the formed third layer (high density layer) was 2.20 as a result of measurement by the X-ray reflectivity method using MXP21 manufactured by MacScience.

(Fourth layer: Medium density layer 2)
The medium density layer 2 was formed under the same conditions as the second layer (medium density layer 1).

As a result of measuring the water vapor transmission rate by a method based on JIS-K-7129B, it was 10 ⁻³ g / m ² / day or less. As a result of measuring the oxygen transmission rate by a method based on JIS-K-7126B, it was 10 ⁻³ g / m ² / day or less.

Next, after patterning a substrate having a 120 nm ITO (indium tin oxide) film formed on the gas barrier film substrate, the substrate with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol and dried with dry nitrogen gas. And UV ozone cleaning was performed for 5 minutes. The ITO substrate 100 was manufactured by fixing to a substrate holder of a commercially available vacuum deposition apparatus and reducing the pressure to 4 × 10 ⁻⁴ Pa.

  Next, while the ink jet head 10 moves at a high speed relative to the ITO substrate 100, the fluid D containing the compound B6 as a hole transport material is discharged toward the upper surface of the substrate 100, whereby the liquid containing the compound B6 is discharged. Droplet D lands. The landed droplet (fluid D) has a diameter of about several tens of μm. Then, a predetermined amount of the fluid D was discharged to form the hole transport layer 111. Next, a polymer thin film was formed at 200 ° C. for 1 hour. The average molecular weight of the formed polymer was about 10,000 (repeating unit 16.6), and the film thickness was 50 nm.

  Similarly, by discharging the fluid D containing the compound B7 as the electron transporting material toward the upper surface of the substrate 100, the droplet containing the compound B7 is landed. The landed droplet has a diameter of about several tens of μm. And the electron carrying layer 112 was formed by discharging a predetermined amount of fluid. Further, a polymer thin film was formed at 200 ° C. for 1 hour. The average molecular weight of the formed polymer was about 20000 (repeating unit 40.5), and the film thickness was 50 nm. Next, aluminum having a thickness of 200 nm was deposited thereon.

  In the sealing, the transparent gas barrier film was used and the gas barrier film was formed on the side facing the cathode, and the organic EL element OLED1-1 of the present invention was formed. When a voltage of 20 V was applied to the device with the ITO side being positive and the aluminum side being negative, green light emission having a peak wavelength of 500 nm was observed.

  FIG. 3 shows the discharge and film forming steps of the organic EL element OLED1-1 of the present invention.

<Preparation of organic EL element OLED2-1>
Except having changed the positive hole transport layer and the electron carrying layer as follows, it carried out similarly to organic EL element OLED1-1, and produced organic EL element OLED2-1 of this invention.

  A fluid D containing Compound A7 and dodecyl mercaptan (molar ratio 10: 1) as a hole transport material was discharged toward the upper surface of the substrate 100 to form a hole transport layer 111. Next, a polymer thin film was formed at 100 ° C. for 1 hour. The average molecular weight of the formed polymer was about 5000 (repeating unit 9.2), and the film thickness was 50 nm.

  Similarly, a fluid D containing Compound A12 and octadecyl alcohol (molar ratio 10: 1) as an electron transport material was discharged toward the upper surface of the substrate 100 to form an electron transport layer 112. Further, a polymer thin film was formed under conditions of 100 ° C. for 1 hour. The formed polymer had an average molecular weight of about 4000 (repeating unit 8.0) and a film thickness of 50 nm.

<Preparation of organic EL element OLED3-1>
A comparative organic EL element OLED3-1 was produced in the same manner as the organic EL element OLED1-1 except that the hole transport layer and the electron transport layer were changed as follows.

As a hole transport layer on the ITO substrate, α-NPD was applied and formed in a film thickness of 50 nm in the same manner as described above, and after drying at 100 ° C. for 30 minutes, Alq ₃ was formed as an electron transporting light-emitting material with a film thickness of 50 nm. A coating film was formed and dried in the same manner. Next, LiF was deposited to a thickness of 0.5 nm and Al was deposited to a thickness of 110 nm to form a cathode, thereby producing a comparative organic EL element OLED3-1.

<Preparation of organic EL element OLED4-1>
Except having changed the positive hole transport layer and the electron carrying layer as follows, the organic EL element OLED4-1 of this invention was produced like the organic EL element OLED1-1.

  A fluid D containing Compound B6 as a hole transport material was discharged toward the upper surface of the substrate 100 to form a hole transport layer 111. Next, a polymer thin film was formed under the conditions of an irradiation electron current of 5 mA and an electron irradiation energy of 50 eV. The formed polymer had an average molecular weight of about 18000 and a film thickness of 50 nm.

Similarly, the fluid D containing the compound B8 as an electron transport material was discharged toward the upper surface of the substrate 100 to form the electron transport layer 112. Further, a polymer thin film was formed under the conditions of an irradiation electron current of 5 mA and an electron irradiation energy of 50 eV. The formed polymer had an average molecular weight of about 15000 and a film thickness of 50 nm. Further, after discharging, a current was passed through the device for 1 hour at a current density of 50 mA / cm ² to increase the degree of polymerization.

<Evaluation of organic EL element>
The organic EL device obtained as described below was evaluated, and the results are shown in Table 1.

(Luminance brightness)
In the organic EL element OLED3-1, a current started to flow at an initial driving voltage of 4 V, and green light emission was displayed. The light emission luminance was expressed as a relative value when the organic electroluminescence element OLED3-1 was taken as 100. The light emission luminance was measured using CS-1000 (manufactured by Konica Minolta Sensing).

(durability)
When driven at a constant current of 10 mA / cm ² , the half-life time, which is the time required for the initial luminance to drop to half of the original, was expressed as an index. The half-life time was expressed as a relative value when the organic EL element OLED3-1 was taken as 100.

Further, after driving for 20 hours at a constant current of 10 mA / cm ² , the number of non-luminous spots (dark spots) that can be visually confirmed in a range of 2 mm × 2 mm square was measured.

  As is clear from Table 1, it has been clarified that the organic EL device using the method according to the present invention significantly reduces dark spots and improves the lifetime. Furthermore, an improvement in light emission luminance was recognized.

Example 2
Under the same conditions as the conditions under which the organic EL element OLED1-1 of Example 1 was manufactured, elements having the materials and film thickness configurations shown in the organic EL elements OLED5-1 to 5-3 in Table 2 below were manufactured. Moreover, the element of the material and film thickness structure which were shown to the organic EL element OLED5-4-5-6 of the following Table 2 on the same conditions as the conditions which produced organic EL element OLED2-1 was produced. Furthermore, comparative organic EL elements OLED5-7 shown in Table 2 below were produced under the same conditions as those for producing organic EL element OLED3-1.

  The organic EL elements OLED5-1 to 5-7 were also evaluated by the same evaluation method as in Example 1. Table 3 shows the evaluation results of the organic EL element.

  As is apparent from the results in Table 3, also in the phosphorescent organic EL element, it was found that the organic EL element of the present invention is a highly durable element with excellent emission luminance and long life and suppressed generation of dark spots. .

  In addition, the organic EL element OLED5-3 in which a compound having a polymerizable group and a compound having a reactive group are combined is more durable than the organic EL element OLED5-1 that uses a compound having a reactive group in the electron transport material. As a result, it is seen that at least a part forms a covalent bond in the vicinity of the interface between the light-emitting layer and the electron transport layer because the durability improvement effect equivalent to that of the organic EL element OLED5-2 is seen. Suggested by

It is a schematic diagram which shows an example of the layer structure of the transparent gas barrier film which concerns on this invention, and its density profile. It is the schematic which shows an example of the atmospheric pressure plasma discharge processing apparatus of the system which processes a base material between counter electrodes useful for this invention. It is a figure which shows the discharge and film-forming process of organic EL element OLED1-1 of this invention.

Explanation of symbols

30 Plasma discharge treatment chamber 25, 35 Roll electrode 36 Electrode 41, 42 Power supply 51 Gas supply device 55 Electrode cooling unit 100 ITO substrate 111 Hole transport layer 112 Electron transport layer 113 Cathode 114 Gas barrier film 10 Inkjet head D droplet

Claims (15)

In an organic electroluminescence device having a cathode and an anode on a substrate and having a plurality of organic layers between them, a repeating unit obtained by coating and polymerizing a compound in which at least one of the organic layers has at least one polymerizable group An organic electroluminescence device, which is a layer containing 10 or less organic molecules. On the organic layer (first layer), another organic layer (second layer) having 10 or less repeating units is laminated by applying and polymerizing a compound containing at least one polymerizable group. The organic electroluminescent element according to claim 1, wherein In an organic electroluminescence device having a cathode and an anode on a substrate and having a plurality of organic layers therebetween, the organic layer (first layer) is coated with a polymerizable group or a compound having a reactive group and polymerized. After that, another organic layer (second layer) is formed by applying and polymerizing a compound having a polymerizable group or a reactive group, and a part of the interface of each layer is shared. An organic electroluminescence element which is bonded through bonding. The organic electroluminescent element according to claim 1, wherein the polymerizable group is a vinyl group. The organic electroluminescence device according to claim 1, wherein the coating is performed by ink jet recording. The organic electroluminescence device according to any one of claims 1 to 5, wherein the polymerization is performed by energy irradiation. The organic electroluminescence device according to claim 6, wherein the energy irradiation is irradiation of ultraviolet rays, electrons, ions, heat, a radical beam or radiation. 8. The compound according to claim 2, wherein the compound of the first layer is a compound having an aromatic tertiary amine structure, and the compound of the second layer is a compound having an organometallic complex structure. 2. The organic electroluminescence device according to item 1. The organic electroluminescent device according to claim 8, wherein the first layer or the second layer further contains a phosphorescent compound. The organic electroluminescence device according to claim 2, wherein the first layer is an electron transport layer and the second layer is a hole transport layer. The organic electroluminescence device according to any one of claims 1 to 10, wherein the substrate is a transparent gas barrier film. Luminescence is white, The organic electroluminescent element of any one of Claims 1-11 characterized by the above-mentioned. A display device comprising the organic electroluminescence element according to claim 12. An illuminating device comprising the organic electroluminescence element according to claim 12. 15. A display device comprising the lighting device according to claim 14 and a liquid crystal element as a display means.

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