WO2013150593A1

WO2013150593A1 - Organic electroluminescent panel and method for producing same

Info

Publication number: WO2013150593A1
Application number: PCT/JP2012/058962
Authority: WO
Inventors: 田中　洋平
Original assignee: パイオニア株式会社
Priority date: 2012-04-02
Filing date: 2012-04-02
Publication date: 2013-10-10

Abstract

This organic electroluminescent panel comprises a transparent conductive film, a functional laminate containing at least one light-emitting layer, and a counter electrode film laminated, in that order, on a substrate. At least a portion of the transparent conductive film has a tapered side, the thickness of which gradually decreases toward the outer edge. The functional laminate covers the tapered side of the transparent conductive film.

Description

Organic electroluminescence panel and manufacturing method thereof

The present invention relates to an organic EL panel including an organic electroluminescence (hereinafter referred to as organic EL) material in a light emitting layer and a method for manufacturing the same.

Organic EL elements are used in display devices as light emitters in which a plurality of functional layers such as a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer are sandwiched between an anode and a cathode. . An organic EL panel is a surface light emitter in which an organic EL element is enlarged.

A display device composed of a plurality of organic EL elements arranged in a matrix is provided with insulating films such as partition walls and banks in order to partition each element (see Patent Documents 1 to 4).

JP 2007-149578 A JP 2011-216317 A Japanese Patent Laid-Open No. 2005-157312 JP 2006-12768 A

In the manufacturing process of such a conventional display device, the anode of the organic EL element is often patterned on the substrate by an etching method such as photolithography, and in this case, the edge shape of the anode becomes steep and unstable. Therefore, an insulating film covering the anode edge is necessary for preventing a short circuit between the anode and the cathode and suppressing cathode disconnection. However, if there is an insulating film, the number of steps for forming the insulating film increases, and accordingly, there is a problem that the cost of the organic EL panel cannot be reduced due to an increase in the yield deterioration factor.

Therefore, the present invention has been made in view of such problems, and the problem to be solved by the present invention is to provide an organic EL panel that can be manufactured at low cost and a method for manufacturing the same as an example of the problem. .

The organic EL panel of the present invention includes a substrate, a transparent conductive film laminated on the substrate, a functional laminate including at least one light emitting layer laminated on the transparent conductive film, and the functional laminate. An organic EL panel including a counter electrode film laminated on a body, wherein the functional laminate includes at least a side surface of the transparent conductive film in an intersecting portion where the transparent conductive film and the counter electrode film overlap each other. It is characterized by being coated.

The manufacturing method of the present invention for manufacturing the organic EL panel includes a substrate, a transparent conductive film laminated on the substrate, and at least one light emitting layer laminated on the transparent conductive film. A method of manufacturing an organic EL panel including a laminate and a counter electrode film laminated on the functional laminate, the step of forming a transparent conductive film on the substrate, and covering the transparent conductive film Forming a functional laminate, wherein in the step of forming the functional laminate, the functional laminate has at least the transparent conductive layer at the intersection where the transparent conductive film and the counter electrode film overlap. At least one layer of the functional laminate is formed by a wet coating method so as to cover the side surface of the film.

It is an upper surface see-through | perspective partial notch top view which shows the structure of the organic electroluminescent panel of embodiment of this invention. FIG. 2 is a partial cross-sectional view taken along line AA in FIG. 1. It is sectional drawing which shows the board | substrate in the manufacturing process of the organic electroluminescent panel of embodiment of this invention, and the structure formed on it. It is sectional drawing which shows the board | substrate in the manufacturing process of the organic electroluminescent panel of embodiment of this invention, and the structure formed on it. It is sectional drawing which shows the board | substrate in the manufacturing process of the organic electroluminescent panel of embodiment of this invention, and the structure formed on it. It is sectional drawing which shows the board | substrate in the manufacturing process of the organic electroluminescent panel of embodiment of this invention, and the structure formed on it. It is sectional drawing which shows the board | substrate in the manufacturing process of the organic electroluminescent panel of embodiment of this invention, and the structure formed on it. It is sectional drawing which shows the board | substrate in the manufacturing process of the organic electroluminescent panel of embodiment of this invention, and the structure formed on it. It is sectional drawing which shows the board | substrate in the manufacturing process of the organic electroluminescent panel of embodiment of this invention, and the structure formed on it. It is sectional drawing which shows the board | substrate in the manufacturing process of the organic electroluminescent panel of embodiment of this invention, and the structure formed on it. It is sectional drawing which shows the board | substrate in the manufacture process of the organic electroluminescent panel of other embodiment of this invention, and the structure formed on it. It is sectional drawing which shows the board | substrate in the manufacture process of the organic electroluminescent panel of other embodiment of this invention, and the structure formed on it.

Hereinafter, an organic EL panel according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective partially cutaway plan view of a portion of the organic EL panel of the embodiment as viewed from the upper surface on the cathode side, and FIG. 2 is a partial cross-sectional view showing a cross section of the organic EL panel taken along line AA in FIG. is there.

As shown in FIG. 2, the organic EL panel includes a transparent anode 2 (a so-called transparent conductive film) formed on a flat transparent substrate 1 made of glass or resin on the light extraction side, And a cathode 9 (so-called counter electrode film) laminated thereon. As the functional layer of the functional laminate FLB capable of emitting white light, for example, hole injection layer 3 / hole transport layer 4 / red / green mixed light emitting layer 5 / blue light emitting layer 6 / electron transport layer 7 / electron injection layer 8 Lamination is mentioned.

As shown in FIGS. 1 and 2, a transparent anode 2 and a cathode 9 extending in the XY direction on the panel plane are formed on the substrate 1 so as to sandwich the functional laminate FLB. A portion where the anode 2 of the transparent conductive film such as ITO, the functional laminate FLB, and the cathode 9 of the counter electrode film overlap is a light emitting portion, and light is extracted from the substrate 1 side.

By increasing the film thickness of the transparent anode 2 to the order of μm exceeding 1 μm, the organic EL panel of the embodiment achieves smoothing of the anode itself as well as low resistance. Such a smooth main surface by increasing the thickness of the anode contributes to smoothing of the functional layer of the functional laminate FLB to be formed in a later process and to reducing film thickness unevenness. In addition to smoothing, thickening the anode can be expected to reduce interference on the light extraction side. For example, when setting the film thickness of the anode, the degree of freedom of the film thickness width that can be made a non-integer multiple of 1/4 of the peak wavelength of each extracted emission color can be expanded. In order to increase the thickness of the anode, the thickness of the transparent anode 2 is preferably 1 μm to 5 μm in order to maintain the transmittance of the transparent anode 2 and ensure panel characteristics.

As shown in FIG. 2, the thickness of the anode 2 gradually decreases toward the edge 2B (most edge) of the anode 2 on the smooth main surface 2A and the main surface of the substrate 1 at the interface with the functional laminate FLB. The film is formed so as to have a tapered side surface 2C. Here, patterning of the anode is usually performed by a photolithography process, and the edge of the ITO anode manufactured by the above process is unstable, and thus needs to be covered with an insulating film. This insulating film process is one of the factors that increase the panel cost and decrease the yield. In order to solve this problem, the anode is preferably patterned by a wet coating method such as screen printing, plateless printing or plate printing, or a sputtering method using a non-contact or contact mask. The functional layer of the functional laminate FLB is preferably formed by coating. When the functional laminate FLB is formed on the tapered side surface 2C of the anode 2, the tapered side surface is also formed on the functional laminate FLB, and disconnection of the cathode formed in a later process can be prevented. Therefore, with the above configuration, an organic EL panel suitable for illumination or the like can be manufactured without requiring an insulating film.

The functional layer of the functional laminate FLB is formed by coating in order to improve the coverage of the anode 2 and the edge 2B. In particular, the first layer (the hole injection layer 3 or the hole transport layer 4) is preferably applied thickly. As the tapered side surface of the functional laminate FLB becomes thicker, the coverage of the anode 2 and the edge 2B increases, so that the effect of suppressing leakage increases. Specifically, the total film thickness of the laminated film from the anode 2 to the light emitting layer 5 of the functional laminated body FLB is preferably at least 100 nm in order to ensure embedding with respect to foreign matter on the anode.

An example of the organic EL panel of the present embodiment is, as shown in FIG. 2, an anode 2 / hole injection layer 3 / hole transport layer 4 / red-green, which are sequentially laminated on a transparent substrate 1 such as glass. The mixed light-emitting layer 5 / blue light-emitting layer 6 / electron transport layer 7 / electron injection layer 8 / cathode 9 / are configured. In addition to this laminated structure, although not shown, the hole transport layer of anode 2 / hole injection layer 3 / red / green mixed light emitting layer 5 / blue light emitting layer 6 / electron transport layer 7 / electron transport layer 8 / cathode 9 / 4 is omitted, and although not shown, hole injection layer of anode 2 / hole transport layer 4 / red / green mixed light emitting layer 5 / blue light emitting layer 6 / electron transport layer 7 / electron injection layer 8 / cathode 9 / 3 is omitted, and although not shown, anode 2 / hole transport layer 4 / red / green mixed light emitting layer 5 / blue light emitting layer 6 / electron injection layer 8 / cathode 9 / hole injection layer 3 and electron transport layer A configuration in which 7 is omitted is also included in the present invention. In any of the above laminated structures, a configuration in which a diffusion preventing layer is provided between the red-green mixed light emitting layer 5 and the blue light emitting layer 6 is also included in the present invention.

As a method for forming a functional layer of an organic EL panel, there are dry coating methods such as a sputtering method and a vacuum deposition method, and wet coating methods such as a screen printing, a spray method, an ink jet method, a spin coater method, a gravure printing, and a roll coater method. Are known. For example, the hole injection layer, the hole transport layer, and the light emitting layer are uniformly formed as a solid film by a wet coating method, and the electron transport layer and the electron injection layer are uniformly formed as a solid film by a dry coating method, respectively. You may form into a film sequentially. Further, all the functional layers may be uniformly and sequentially formed as a solid film by a wet coating method.

[substrate]
As the substrate 1, a quartz or glass plate, a metal plate or a metal foil, a resin substrate to be bent, a plastic film, a sheet, or the like is used. In particular, a glass plate or a transparent plate made of a synthetic resin such as polyester, polymethacrylate, polycarbonate, or polysulfone is preferable. When using a synthetic resin substrate, it is necessary to pay attention to gas barrier properties. If the gas barrier property of the substrate is too small, the organic EL panel may be deteriorated by the outside air that has passed through the substrate, which is not preferable. Therefore, a method of securing a gas barrier property by providing a dense silicon oxide film or the like on at least one surface of the synthetic resin substrate is also a preferable method.

In addition, when forming a transparent anode with a thick film by a wet coating method, since the unevenness | corrugation of a board | substrate surface can be eased, the cheap glass substrate which is not an expensive polishing glass substrate for displays can also be used for an organic EL panel substrate.

[Anode and cathode]
The anode 2 for supplying holes to the functional layers up to the light emitting layer is usually composed of a composite oxide (so-called ITO) of indium oxide and tin oxide. In addition to ITO, the anode 2 may be ZnO, ZnO—Al ₂ O ₃ (so-called AZO), In ₂ O ₃ —ZnO (so-called IZO), SnO ₂ —Sb ₂ O ₃ (so-called ATO), RuO _2, etc. Can be configured. Furthermore, as the transparent conductive film of the anode 2, it is preferable to select a material having a transmittance of at least 10% at the emission wavelength obtained from the organic EL material.

The anode usually has a single-layer structure, but it can also have a laminated structure made of a plurality of materials if desired.

The surface of the anode is treated with ultraviolet (UV) / ozone, oxygen plasma, or argon plasma for the purpose of removing impurities adhering to the anode and adjusting the ionization potential to improve hole injection. Is preferred.

The material of the cathode 9 for supplying electrons to the functional layers up to the light emitting layer is preferably a metal having a low work function in order to perform electron injection efficiently, for example, tin, magnesium, indium, calcium, aluminum, silver, etc. New metals or their alloys are used. Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

In addition, only 1 type may be used for the material of the cathode 9, and 2 or more types may be used together by arbitrary combinations and a ratio.

Further, for the purpose of protecting the cathode made of a low work function metal, it is preferable to further stack a metal layer having a high work function and stable to the atmosphere on the cathode because the stability of the organic EL panel is increased. For this purpose, for example, metals such as aluminum, silver, copper, nickel, chromium, gold and platinum are used. In addition, these materials may be used only by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

[Functional layer of functional laminate]
[Hole injection layer]
The hole injection layer 3 is preferably a layer containing an electron accepting compound.

When forming by a wet coating method, the composition for forming a hole injection layer usually contains a hole transporting compound and a solvent as a constituent material of the hole injection layer. Examples of the solvent include, but are not limited to, ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents, and the like. Examples of ether solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether acetate (so-called PGMEA), 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, and phenetole. , Aromatic ethers such as 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole.

Examples of the ester solvent include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate.

Examples of the aromatic hydrocarbon solvent include toluene, xylene, cyclohexylbenzene, 3- isopropylpropylphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, cyclohexylbenzene, methylnaphthalene and the like. Can be mentioned.

Examples of the amide solvent include N, N-dimethylformamide and N, N-dimethylacetamide. In addition, dimethyl sulfoxide and the like can also be used. These solvent may use only 1 type and may use 2 or more types by arbitrary combinations and a ratio.

As long as the hole transporting compound is a compound having a hole transporting property that is usually used in a hole injection layer of an organic EL panel, a polymer or the like may be a monomer or the like. Although it may be a low molecular compound, it is preferably a low molecular compound.

The hole transporting compound is preferably a compound having an ionization potential of 4.5 eV to 6.0 eV from the viewpoint of a charge injection barrier from the anode to the hole injection layer. Examples of hole transporting compounds include aromatic amine derivatives, phthalocyanine derivatives represented by phthalocyanine copper (so-called CuPc), porphyrin derivatives, oligothiophene derivatives, polythiophene derivatives, benzylphenyl derivatives, tertiary amines with fluorene groups. Examples include linked compounds, hydrazone derivatives, silazane derivatives, silanamine derivatives, phosphamine derivatives, quinacridone derivatives, polyaniline derivatives, polypyrrole derivatives, polyphenylene vinylene derivatives, polythienylene vinylene derivatives, polyquinoline derivatives, polyquinoxaline derivatives, and carbon. Here, the derivative includes, for example, an aromatic amine derivative, and includes an aromatic amine itself and a compound having an aromatic amine as a main skeleton. There may be.

As the hole transporting compound, a conductive polymer obtained by polymerizing 3,4-ethylenedioxythiophene, which is a polythiophene derivative, in high molecular weight polystyrene sulfonic acid (so-called PEDOT / PSS) is also preferable. Furthermore, the end of the polymer of PEDOT / PSS may be capped with methacrylate or the like.

The hole transporting compound used as the material for the hole injection layer may contain any one of these compounds alone, or may contain two or more. In the case of containing two or more kinds of hole transporting compounds, the combination is arbitrary, but one or more kinds of aromatic tertiary amine polymer compounds and one or two kinds of other hole transporting compounds. The above can also be used together. From the viewpoints of amorphousness and visible light transmittance, an aromatic amine compound is preferable for the hole injection layer, and an aromatic tertiary amine compound is particularly preferable. Here, the aromatic tertiary amine compound is a compound having an aromatic tertiary amine structure, and includes a compound having a group derived from an aromatic tertiary amine.

The concentration of the hole transporting compound in the composition for forming a hole injection layer is usually 0.01% by weight or more, preferably 0.1% by weight or more, and more preferably 0.00% by weight in terms of film thickness uniformity. 5% by weight or more, usually 70% by weight or less, preferably 60% by weight or less, more preferably 50% by weight or less. If this concentration is too high, film thickness unevenness may occur, and if it is too low, defects may occur in the formed hole injection layer.

The composition for forming a hole injection layer preferably contains an electron-accepting compound, and may further contain other components in addition to the hole-transporting compound and the electron-accepting compound. Examples of other components include various organic EL materials, electron transport compounds, binder resins, coatability improvers, and the like. In addition, only 1 type may be used for another component and it may use 2 or more types together by arbitrary combinations and ratios.

When forming a hole injection layer by a wet coating method, the material for forming the hole injection layer is usually mixed with an appropriate solvent (solvent for the hole injection layer) to form a composition for film formation (hole injection). A composition for forming a layer) is prepared, and this composition for forming a hole injection layer is coated on the anode by an appropriate technique to form a film and dried to form a hole injection layer.

The film thickness of the hole injection layer is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

[Hole transport layer]
The material for the hole transport layer 4 may be any material that has been conventionally used as a constituent material for the hole transport layer. Things. In addition, arylamine derivatives, fluorene derivatives, spiro derivatives, carbazole derivatives, pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, phthalocyanine derivatives, porphyrin derivatives, silole derivatives, oligothiophene derivatives, condensed polycyclic aromatics Group derivatives, metal complexes and the like. Also, for example, polyvinylcarbazole derivatives, polyarylamine derivatives, polyvinyltriphenylamine derivatives, polyfluorene derivatives, polyarylene derivatives, polyarylene ether sulfone derivatives containing tetraphenylbenzidine, polyarylene vinylene derivatives, polysiloxane derivatives, polythiophenes Derivatives, poly (p-phenylene vinylene) derivatives, and the like. These may be any of an alternating copolymer, a random polymer, a block polymer, or a graft copolymer. Further, it may be a polymer having a branched main chain and three or more terminal portions, or a so-called dendrimer.

When the hole transport layer is formed by a wet coating method, a composition for forming a hole transport layer is prepared in the same manner as the formation of the hole injection layer, and then dried after wet film formation.

In addition to the hole transporting compound, the hole transporting layer forming composition contains a solvent. The solvent used is the same as that used for the composition for forming the hole injection layer. The film forming conditions, the drying conditions, and the like are the same as in the case of forming the hole injection layer.

The hole transport layer may contain various organic EL materials, electron transport compounds, binder resins, coatability improvers, and the like in addition to the hole transport compound.

The film thickness of the hole transport layer is usually 5 nm or more, preferably 10 nm or more, and usually 300 nm or less, preferably 100 nm or less.

Since at least the hole injection layer 3 or the hole transport layer 4 is preferably applied thickly as described above, the film thickness of the hole injection layer 3 and / or the hole transport layer 4 from the anode 2 to the light emitting layer 5 Is preferably at least 100 nm.

[Light emitting layer]
The light-emitting layers of the red-green mixed light-emitting layer and the blue light-emitting layer contain an organic EL material, and preferably a compound having a hole transport property (hole transport compound) or a compound having an electron transport property (electron transport) A functional compound). An organic EL material may be used as a dopant material, and a hole transporting compound, an electron transporting compound, or the like may be appropriately used as a host material. There is no particular limitation on the organic EL material, and a substance that emits light at a desired emission wavelength and has good emission efficiency may be used.

Any known material can be applied as the organic EL material. For example, it may be a fluorescent material or a phosphorescent material, but it is preferable to use a phosphorescent material from the viewpoint of internal quantum efficiency. The light emitting layer may have a single layer structure or a multilayer structure made of a plurality of materials as desired. For example, a fluorescent material may be used for the blue light emitting layer, and a phosphorescent material may be used for the green and red light emitting layers. Further, a diffusion preventing layer can be provided between the light emitting layers.

Examples of fluorescent materials (blue fluorescent dyes) that emit blue light include naphthalene, perylene, pyrene, chrysene, anthracene, coumarin, p-bis (2-phenylethenyl) benzene, and derivatives thereof.

Examples of the fluorescent material (green fluorescent dye) that emits green light include aluminum complexes such as quinacridone derivatives, coumarin derivatives, and Alq3 (tris (8-hydroxy-quinoline) aluminum).

Examples of fluorescent materials that give yellow light emission (yellow fluorescent dyes) include rubrene and perimidone derivatives.

Examples of fluorescent materials that give red light emission (red fluorescent dyes) include DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, benzoates. Examples thereof include thioxanthene derivatives and azabenzothioxanthene.

The phosphorescent material is selected from, for example, the long-period periodic table (hereinafter referred to as the long-period periodic table when referring to “periodic table” unless otherwise specified). An organometallic complex containing a metal can be given. Preferred examples of the metal selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, and gold. As the ligand of the complex, a ligand in which a (hetero) aryl group such as a (hetero) arylpyridine ligand or a (hetero) arylpyrazole ligand and a pyridine, pyrazole, phenanthroline, or the like is connected is preferable. A pyridine ligand and a phenylpyrazole ligand are preferable. Here, (hetero) aryl represents an aryl group or a heteroaryl group.

Specific examples of phosphorescent materials include tris (2-phenylpyridine) iridium (so-called Ir (ppy) 3), tris (2-phenylpyridine) ruthenium, tris (2-phenylpyridine) palladium, and bis (2-phenyl). Pyridine) platinum, tris (2-phenylpyridine) osmium, tris (2-phenylpyridine) rhenium, octaethylplatinum porphyrin, octaphenylplatinum porphyrin, octaethyl palladium porphyrin, octaphenyl palladium porphyrin, and the like.

The molecular weight of the compound used as the organic EL material is usually 10,000 or less, preferably 5000 or less, more preferably 4000 or less, still more preferably 3000 or less, and usually 100 or more, preferably 200 or more, more preferably 300 or more, still more preferably. Is in the range of 400 or more. If the molecular weight of the organic EL material is too small, the heat resistance will be significantly reduced, gas generation will be caused, the film quality will be deteriorated when the film is formed, or the morphology of the functional layer will be changed due to migration, etc. There is a case. On the other hand, if the molecular weight of the organic EL material is too large, it tends to be difficult to purify the organic compound, or it may take time to dissolve the organic EL material in a solvent when formed by a wet coating method.

In addition, only 1 type may be used for an organic EL material, and 2 or more types may be used together by arbitrary combinations and a ratio. The proportion of the organic EL material in the light emitting layer is usually 0.05% by weight or more and usually 35% by weight or less. If the amount of the organic EL material is too small, uneven light emission may occur, and if the amount is too large, the light emission efficiency may be reduced. In addition, when using together 2 or more types of organic EL material, it is made for the total content of these to be contained in the said range. The component having the highest content in the light emitting layer is called a host material, and the component having a smaller content is called a guest material.

The light emitting layer may contain a hole transporting compound as a constituent material. Here, among the hole transporting compounds, examples of the low molecular weight hole transporting compound include various compounds exemplified as the hole transporting compound in the hole injection layer 3 described above, for example, 2 'or more condensed aromatic rings containing 2 or more tertiary amines represented by 4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (so-called α-NPD) are nitrogen From aromatic diamines substituted with atoms, aromatic amine compounds having a starburst structure such as 4,4 ′, 4 ″ -tris (1-naphthylphenylamino) triphenylamine, and tetramers of triphenylamine And spiro compounds such as 2,2 ′, 7,7′-tetrakis- (diphenylamino) -9,9′-spirobifluorene.

In addition, in a light emitting layer, only 1 type may be used for a hole transportable compound, and it may use 2 or more types together by arbitrary combinations and a ratio.

The proportion of the hole transporting compound in the light emitting layer is usually 0.1% by weight or more and usually 65% by weight or less. If the amount of the hole transporting compound is too small, it may be easily affected by a short circuit, and if it is too large, the film thickness may be uneven. In addition, when using together 2 or more types of hole transportable compounds, it is made for the total content of these to be contained in the said range.

The light emitting layer may contain an electron transporting compound as a constituent material. Here, among the electron transporting compounds, examples of low molecular weight electron transporting compounds include 2,5-bis (1-naphthyl) -1,3,4-oxadiazole (so-called BND), 2 , 5-bis (6'-
(2 ′, 2 ″ -bipyridyl))-1,1-dimethyl-3,4-diphenylsilole (so-called PyPySPyPy), bathophenanthroline (so-called BPhen), 2,9-dimethyl-4,7-diphenyl 1,10-phenanthroline (so-called BCP, bathocuproin), 2- (4-biphenylyl) -5- (p-tert-butylphenyl) -1,3,4-oxadiazole (so-called tBu-PBD), 4,4′-bis (9H-carbazol-9-yl) biphenyl (so-called CBP), etc. In the light emitting layer, only one kind of electron transporting compound may be used. The above may be used in any combination and ratio.

The proportion of the electron transporting compound in the light emitting layer is usually 0.1% by weight or more and usually 65% by weight or less. If the amount of the electron transporting compound is too small, it may be easily affected by a short circuit, and if it is too large, the film thickness may be uneven. In addition, when using together 2 or more types of electron transport compounds, it is made for the total content of these to be contained in the said range.

In the case of forming by a wet coating method, the light emitting layer is prepared by dissolving the above light emitting layer material in an appropriate solvent to prepare a composition for forming a light emitting layer. Is formed. Therefore, in the case of forming by a wet coating method, the light emitting layer coating solution is prepared by dispersing or dissolving at least two kinds of solid contents (host material and guest material) to be the light emitting layer as a solute in a solvent. The solvent to be used can be selected from the solvents that can be used for the composition for forming a hole injection layer.

The ratio of the light emitting layer solvent to the light emitting layer forming composition for forming the light emitting layer is usually 0.01% by weight or more and usually 70% by weight or less. In addition, when using 2 or more types of solvents mixed as a solvent for light emitting layers, it is made for the sum total of these solvents to satisfy | fill this range.

The film thickness of the light emitting layer is usually 3 nm or more, preferably 5 nm or more, and usually 200 nm or less, preferably 100 nm or less. If the light emitting layer is too thin, defects may occur in the film, and if it is too thick, the driving voltage may increase.

[Electron transport layer]
The electron transport layer 7 is provided for the purpose of further improving the light emission efficiency of the organic EL panel, and efficiently transports electrons injected from the cathode between the electrodes to which an electric field is applied in the direction of the light emitting layer. Formed from a compound capable of

As the electron transporting compound used for the electron transport layer, usually, the electron injection efficiency from the cathode 9 or the electron injection layer 8 is high, and the injected electrons having high electron mobility can be efficiently transported. Use possible compounds. Examples of compounds that satisfy such conditions include metal complexes of Alq3 and 10-hydroxybenzo [h] quinoline, oxadiazole derivatives, distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, and 5-hydroxyflavones. Metal complex, benzoxazole metal complex, benzothiazole metal complex, trisbenzimidazolylbenzene, quinoxaline compound, phenanthroline derivative, 2-t-butyl-9,10-N, N′-dicyanoanthraquinonediimine, n-type hydrogenated amorphous Quality silicon carbide, n-type zinc sulfide, n-type zinc selenide and the like.

In addition, only 1 type may be used for the material of an electron carrying layer, and 2 or more types may be used together by arbitrary combinations and a ratio.

The formation method of the electron transport layer is not limited, and can be formed by a wet coating method or a dry coating method. In the case of forming by a wet coating method, the electron transport layer is prepared by dissolving the electron transport layer material in an appropriate solvent to prepare a composition for forming an electron transport layer. It is formed by removing. The solvent to be used can be selected from the solvents that can be used for the composition for forming a hole injection layer.

The film thickness of the electron transport layer is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

[Electron injection layer]
The electron injection layer 8 plays a role of efficiently injecting electrons injected from the cathode into the light emitting layer. In order to perform electron injection efficiently, the material for forming the electron injection layer is preferably a metal having a low work function. Examples include alkali metals such as sodium and cesium, alkaline earth metals such as barium and calcium, and their compounds (CsF, Cs ₂ CO ₃ , Li ₂ O, LiF) and the like. .1 nm or more and 5 nm or less are preferable.

Further, an organic electron transport compound represented by a metal complex such as a nitrogen-containing heterocyclic compound such as bathophenanthroline or an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium, or rubidium. As a result, the electron injecting and transporting properties can be improved and excellent film quality can be achieved at the same time. In this case, the film thickness is usually 5 nm or more, preferably 10 nm or more, and is usually 200 nm or less, preferably 100 nm or less.

In addition, only 1 type may be used for the material of an electron injection layer, and 2 or more types may be used together by arbitrary combinations and a ratio.

The formation method of the electron injection layer is not limited, and can be formed by a wet coating method or a dry coating method. In the case of forming by a wet coating method, the electron injection layer is prepared by dissolving the electron injection layer material in a suitable solvent to prepare a composition for forming an electron injection layer. It is formed by removing. The solvent to be used can be selected from the solvents that can be used for the composition for forming a hole injection layer.

Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

3 to 10 are cross-sectional views showing a substrate and a structure formed thereon in the manufacturing process of the organic EL panel manufacturing method to which the present invention is applied. This manufacturing process will be described in the order of the following (a) cleaning step, (b) anode forming step, (c) hole transport layer forming step, (d) coating light emitting layer forming step, and (e) vapor deposition light emitting layer forming step. To do.

(A) Cleaning Step First, as shown in FIG. 3, for example, a transparent substrate 1 made of a cleaned glass plate having a thickness of 0.7 mm is prepared. In FIG. 3, the cross section along the juxtaposition direction Y orthogonal to the direction X is shown, and this also applies to the following drawings.

(B) Anode formation step As shown in FIG. 4, an IZO (In ₂ O ₃₎ layer is formed on the main surface of the substrate 1 by sputtering using a non-contact or contact mask disposed away from the main surface of the substrate 1. A transparent anode 2 of -ZnO) is formed. A spray material of an IZO target is deposited on the substrate 1 through the pattern opening of the mask, and an IZO film having a predetermined pattern with a tapered edge is obtained as the anode 2 (transparent conductive film). Since the splash material wraps around between the mask opening and the mask substrate, a tapered side surface 2C in which the film thickness gradually decreases from the smooth main surface 2A of the main surface of the transparent anode 2 toward the edge portion 2B is formed.

The thickness of the anode 2 is 1000 nm, for example.

(C) Hole Injection / Transport Layer Formation Step First, as a pretreatment using an excimer light irradiation device (not shown), UV / O ₃ (ultraviolet / ozone) is irradiated on the anode 2 to clean the IZO surface. To do.

As the hole injection layer material, an aqueous dispersion having a fixed concentration of 1 wt% using PEDOT (poly 3,4-ethylenedioxythiophene) as a host and PSS (polystyrene sulfonic acid) as a dopant is prepared.

After the pretreatment, as shown in FIG. 5, the droplet Lq for the hole injection layer material is applied onto the entire surface of the anode 2 by the inkjet head 12 using an inkjet apparatus. For example, when the inkjet head 12 is raster-scanned on the XY plane on the anode 2, a droplet film that covers the edges of the anode 2 by connecting the edges of the applied droplets OG is formed.

Next, the droplet film is vacuum-dried at a gas pressure of 0.1 to 50 Pa for 2 minutes using a vacuum drying apparatus, and baked by heat treatment at 230 ° C. for 1 hour. As shown in FIG. 6, the solvent of the droplets evaporates to obtain a cured hole injection layer 3 that covers the edge of the anode 2.

Similarly to the hole injection layer, the hole transport layer 4 is formed by using an organic solvent droplet having a predetermined concentration of 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane by an inkjet method. As shown in FIG. 2, the entire surface of the hole injection layer 3 is applied and dried. Each of the hole injection layer 3 and the hole transport layer 4 has a thickness of 50 nm, for example.
(D) Coating light emitting layer forming step As a red / green mixed light emitting layer material, Balq (Bis- (2-methyl-8-quinolinolato) (p-phenylphenolato) aluminum) is used as a host, and Hex-Ir (phq) 3 ( An organic solution having a fixed concentration of 6 wt% using Tris [2- (4-n-hexylphenyl) quinoline)] iridium (III)) is prepared in advance.

As shown in FIG. 8, the red / green mixed light emitting layer material droplet Lq is applied onto the entire surface of the hole transport layer 4 by the inkjet head 12 in the same manner as the inkjet method described above.

Next, the droplet film is vacuum-dried for 2 minutes at a gas pressure of 0.1 to 50 Pa using a vacuum drying apparatus, and baked by heat treatment at 130 ° C. for 10 minutes. As a result, as shown in FIG. 9, a cured red-green mixed light emitting layer 5 covering the hole transport layer 4 is obtained. The thickness of the red / green mixed light emitting layer 5 is, for example, 40 nm.
(E) Vapor Deposition Layer Formation Step Using a vacuum deposition apparatus, the host 9,10-di (2-naphthyl) anthracene (so-called ADN) and the concentration of 6 wt% are formed on the red-green mixed light-emitting layer 5. The dopant 4,4′-bis (2,2′-diphenylvinyl) biphenyl (so-called DPVBi) is vacuum-deposited together, whereby the blue light emitting layer 6 is formed with a thickness of, for example, 15 nm.

Next, Alq3 is vacuum-deposited on the blue light emitting layer 6 by a vacuum deposition method, whereby an Alq3 electron transport layer 7 is formed to a thickness of, for example, 30 nm.

Next, LiF (lithium fluoride) is vacuum-deposited on the electron transport layer 7 by a vacuum deposition method, whereby the electron injection layer 8 is formed with a thickness of, for example, 1 nm.

Finally, Al (aluminum) is vacuum-deposited on the electron injection layer 8 by a vacuum deposition method using a mask having a predetermined pattern opening, whereby the cathode 9 is formed with a thickness of, for example, 80 nm. As shown in FIG. 10, the functional laminate FLB is formed from the hole injection layer 3 to the electron injection layer 8 here. The cathode 9 is formed in a strip shape so as to cross the transparent anode 2 along the juxtaposed direction Y orthogonal to the direction X. A portion where the anode 2 and the cathode 9 overlap with each other to sandwich the functional laminate FLB defines a light emitting area of the organic EL panel. Thereafter, a sealed organic EL panel can be obtained through a sealing step. Since the functional laminate FLB covers at least the side surface of the anode 2 in the light emitting area where the anode 2 and the cathode 9 overlap, even if there is no insulating film, the short circuit between the anode 2 and the cathode 9 and the cathode disconnection are suppressed. Is possible.

Thus, according to the embodiment, (a) cleaning step, (b) anode forming step, (c) hole transport layer forming step, (d) coating light emitting layer forming step, and (e) vapor deposition light emitting layer forming step. An organic EL panel is manufactured. In the above embodiment, the blue light-emitting layer 6 is formed by vacuum deposition, but all the light-emitting layers are formed by a combination of an ink jet coating process and a drying process, and coating and drying are performed for each functional layer that performs each function. Repeatedly, as shown in FIG. 10, a multilayer functional laminate FLB (hole injection layer 3 / hole transport layer 4 / red / green mixed light emitting layer 5 / blue light emitting layer 6 / electron transport layer 7) is formed. May be.

For example, in the conventional organic LED, an insulating bank material is used, and since the bank material generally uses a material that absorbs in the visible region such as a polyimide material, the color of the cathode is a metallic color. May damage the appearance. Moreover, since there is an absorbing material in the visible region, the emitted light may be lost in the bank. On the other hand, in the above-described embodiments, there is no insulating film such as a bank material and the organic EL panel emits, so that a higher aperture ratio can be obtained than before. As described above, since the emitted light can be emitted more efficiently for increasing the aperture ratio, the power consumption can be reduced as compared with the conventional element in order to obtain a desired light amount.

In the above-described embodiment, two layers of the hole injection layer 3 and the hole transport layer 4 are formed on the anode 2 (transparent conductive film), but it is not limited to the formation of two layers, Only one layer of the hole injection layer or the hole transport layer, or three or more layers obtained by adding an electron blocking layer (not shown) to the hole injection layer and the hole transport layer may be formed by the light emitting layer.

In addition, the conditions such as the formation method of each film, the width and thickness of each film, the heating temperature, and the heating time in each step shown in the above-described embodiments are merely examples, and the present invention is not limited thereto.

[Other embodiments]
In the above-described embodiment, the anode 2 is patterned by a sputtering method using a non-contact or close contact mask. The anode 2 can be formed by a wet coating method such as a screen printing method, an ink jet method, a spray coating method, a roll coating method, and a plate printing method in addition to the sputtering method.

For example, an IZO paste is applied on a substrate by inkjet printing to form an IZO paste coating film. As shown in FIG. 11, droplets Iq of IZO paste are applied in a predetermined pattern onto the substrate 1 by the inkjet head 12. Then, the substrate 1 is dried (for example, 150 to 200 ° C.) and then fired (for example, 400 to 600 ° C.) to form the anode 2 having a predetermined pattern on the substrate 1 as shown in FIG. In the case of this manufacturing method, since the anode 2 can be formed without a mask or an etching process, the film formation of the anode 2 is simplified. Furthermore, an IZO anode 2 (transparent conductive film) having a smooth main surface 2A and a tapered side surface 2C whose thickness gradually decreases toward the edge 2B can be easily obtained by sagging by printing.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Red-green mixed light emission layer 6 Blue light emission layer 7 Electron transport layer 8 Electron injection layer 9 Cathode

Claims

A substrate, a transparent conductive film laminated on the substrate, a functional laminate including at least one light emitting layer laminated on the transparent conductive film, and a counter electrode laminated on the functional laminate An organic EL panel including a film,
The organic EL panel, wherein the functional laminate covers at least a side surface of the transparent conductive film in an intersecting portion where the transparent conductive film and the counter electrode film overlap.
At least a part of the transparent conductive film has a tapered side surface in which the film thickness gradually decreases toward the outermost edge,
The organic EL panel according to claim 1, wherein the functional laminate covers the tapered side surface of the transparent conductive film.
3. The organic EL panel according to claim 2, wherein at least a part of an end portion of the functional laminate reaches the substrate.
3. The organic EL panel according to claim 2, wherein at least a part of the end portion of the counter electrode film reaches the substrate.
2. The organic EL panel according to claim 1, wherein the transparent conductive film is formed by a wet coating method or a sputtering method using a mask.
A substrate, a transparent conductive film laminated on the substrate, a functional laminate including at least one light emitting layer laminated on the transparent conductive film, and a counter electrode laminated on the functional laminate A method of manufacturing an organic EL panel including a film,
Forming a transparent conductive film on the substrate;
Forming a functional laminate that covers the transparent conductive film, and
In the step of forming the functional laminate, a wet coating method is used so that the functional laminate covers at least a side surface of the transparent conductive film in an intersection where the transparent conductive film and the counter electrode film overlap. A method for producing an organic EL panel, comprising forming at least one layer of the functional laminate.