JP2010073579A - Method of manufacturing organic el element, and coater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an organic element and a coater wherein uniformity of film thickness of an organic EL device is improved when a coating liquid containing organic EL materials is print-coated. <P>SOLUTION: The coating liquid containing the organic EL material to constitute an organic layer, a first solvent of which vapor pressure is 100 Pa or less at 20°C, and a second solvent of which vapor pressure is 500 Pa or more at 20°C, is print-coated on the substrate to form the organic layer. The coating liquid is ejected from at least one nozzle and supplied on the circumferential side face of the roller which supplies the coating liquid. According to an uneven pattern wound around and formed on the outer peripheral surface of a plate cylinder, and by means that the surface of the printing plate which holds the coating liquid by the surface and the circumferential side face of the roller are brought into the vicinity or contacted and rotated, the coating liquid ejected and supplied on the circumferential side face is supplied to the surface of the printing plate. Then, in a state that the surface of the substrate and the printing plate are brought into the vicinity or contacted, the placing table of which the substrate is placed on the upper face and the plate cylinder are relatively moved while rotating the plate cylinder around the core axis. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic EL element manufacturing method and a coating apparatus, and more particularly to an organic EL element manufacturing method and a coating apparatus for printing and applying a coating liquid onto a substrate placed on a stage.

  An organic EL device is actively used for illumination and display. When manufacturing these organic EL devices, organic EL materials, hole transport materials, electron transport materials, etc. are applied to the substrate in a relatively large-sized thin film, or red, green, and blue light emitting materials are applied. It is necessary to coat the organic EL material into fine stripes. By repeating these coating operations and stacking the layers, a light emitting layer, a hole transport layer, an electron transport layer, and the like of the organic EL device are formed.

As an organic EL material used as a material for the light emitting layer, there is a polymer material formed into a thin film by coating (hereinafter referred to as a polymer organic EL material). And the manufacturing method which forms the thin film of a polymeric organic EL material on a board | substrate using various printing methods and a special coating method is tried. For example, a printing apparatus is disclosed that forms a thin film of a polymer organic EL material by printing and applying a polymer organic EL material to a substrate using a printing plate wound around a plate cylinder (see, for example, Patent Document 1). ).
JP 2008-6705 A

  Here, the thin film of the polymer organic EL material is required to have a uniform film thickness in order to prevent light emission unevenness and electric field concentration. For example, in the case where the polymer organic EL material is applied in fine stripes by the above-described printing method, the ink-like polymer organic EL material is printed and applied in a wet state on the substrate. Therefore, the shape after printing and coating is roughly determined by the difference in surface energy between the object to be coated and the polymer organic EL material. In general, as shown in FIG. 9, the cross-sectional shape of the polymer organic EL material that has been applied by printing may be a so-called “kamaboko” shape, and the uniformity of the film thickness is inferior, so Quality and performance may be degraded. Even in the printing apparatus disclosed in Patent Document 1, it is possible to coat the polymer organic EL material in fine stripes, but the cross-sectional shape of the printed organic organic EL material is a “kamaboko” shape. May be.

  When the polymer organic EL material is printed and applied by the above printing method, it is conceivable to use an aromatic high-boiling solvent such as tetralin or cyclohexylbenzene in order to make the polymer organic EL material into an ink. By using this high-boiling solvent, it is possible to lengthen the leveling time for smoothing and homogenizing the coating surface after printing and applying the polymer organic EL material, so that improvement in film thickness uniformity can be expected. However, since the time for maintaining the wet state after printing and applying the polymer organic EL material becomes longer and the drying speed of the solvent is slower, the solvent volatilizes over the entire surface of the polymer organic EL material, so printing Drying is performed while maintaining the cross-sectional shape immediately after application (that is, the “kamaboko” shape).

  Therefore, an object of the present invention is to provide an organic EL element manufacturing method and a coating apparatus that improve film thickness uniformity when a coating liquid containing an organic EL material is applied by printing.

In order to achieve the above object, the present invention has the following features.
1st invention is a manufacturing method of the organic EL element which has an anode, a cathode, and the organic layer located between an anode and a cathode. The manufacturing method of an organic EL element includes the process of forming an organic layer. The step of forming the organic layer includes an organic EL material constituting the organic layer, a first solvent having a vapor pressure at 20 ° C. of 100 Pa or less, and a second solvent having a vapor pressure at 20 ° C. of 500 Pa or more. An organic layer is formed by printing and applying a coating solution on a substrate. The step of forming the organic layer includes a step of placing, a step of supplying and discharging, a step of supplying the coating liquid to the surface of the printing plate, and a step of relative movement. In the placing step, the substrate is placed on the upper surface of the placing table. In the discharging and supplying step, the coating liquid is discharged and supplied from at least one nozzle onto the circumferential side surface of the coating liquid supply roller. The step of supplying the coating liquid to the surface of the printing plate includes the surface of the printing plate wound around the outer peripheral surface of the plate cylinder and holding the coating liquid on the surface according to the uneven pattern formed on the surface, and the coating liquid By rotating the supply roller in proximity to or in contact with the circumferential side surface, the coating liquid discharged and supplied onto the circumferential side surface is supplied to the surface of the printing plate. In the relative movement step, the mounting table and the plate cylinder are relatively moved while the plate cylinder is rotated around the axis while the substrate surface and the printing plate are brought close to or in contact with each other.

  In a second aspect based on the first aspect, the coating liquid further contains a third solvent having a vapor pressure at 20 ° C. of 100 Pa to 500 Pa.

  According to a third invention, in the first or second invention, the coating solution contains the first solvent in a range of 35 to 70 wt%.

  In a fourth aspect based on any one of the first to third aspects, the coating solution contains the second solvent in a range of 5 to 15 wt%.

  In a fifth aspect based on the second aspect, the coating solution contains a third solvent in a range of 25 to 50 wt%.

  In a sixth aspect based on the fifth aspect, the coating solution contains the first solvent in the range of 35 to 70 wt% and the second solvent in the range of 5 to 15 wt%.

  A seventh invention is a coating apparatus that prints and applies a coating liquid containing an organic EL material on a substrate. The coating apparatus includes a mounting table, a plate cylinder, a printing plate, a coating liquid supply unit, and a relative movement unit. The mounting table places the substrate on the upper surface thereof. The printing plate is wound around the outer peripheral surface of the plate cylinder and holds the coating liquid on the surface according to the uneven pattern formed on the surface. The coating liquid supply unit supplies the coating liquid to the surface of the printing plate. The relative movement means moves the mounting table and the plate cylinder relative to each other while rotating the plate cylinder about the shaft core in a state where the upper surface of the substrate and the printing plate are brought close to or in contact with each other. The coating liquid supply unit includes a coating liquid supply roller and at least one nozzle. The coating liquid supply roller supplies the coating liquid held on the circumferential side surface to the surface of the printing plate by rotating the circumferential side surface close to or in contact with the printing plate. The nozzle discharges the coating liquid onto the circumferential side surface of the coating liquid supply roller, and supplies the coating liquid onto the circumferential side surface. The coating liquid contains at least an organic EL material, a first solvent, and a second solvent. The first solvent has a vapor pressure at 20 ° C. of 100 Pa or less. The second solvent has a vapor pressure at 20 ° C. of 500 Pa or more.

  In an eighth aspect based on the seventh aspect, the coating liquid further contains a third solvent. The third solvent has a vapor pressure of 100 Pa to 500 Pa at 20 ° C.

  In a ninth aspect based on the seventh or eighth aspect, the coating solution contains the first solvent in a range of 35 to 70 wt%.

  According to a tenth aspect, in any one of the seventh to ninth aspects, the coating solution contains the second solvent in a range of 5 to 15 wt%.

  In an eleventh aspect based on the eighth aspect, the coating solution contains the third solvent in a range of 25 to 50 wt%.

  In a twelfth aspect based on the eleventh aspect, the coating solution contains the first solvent in a range of 35 to 70 wt% and the second solvent in a range of 5 to 15 wt%.

  In a thirteenth aspect based on the seventh aspect, the nozzle is a single slit nozzle having a slit facing the circumferential side surface with the axial direction of the coating liquid supply roller as the longitudinal direction.

  14th invention is a coating device which print-coats the coating liquid containing organic EL material on a board | substrate. The coating apparatus includes a mounting table, a plate cylinder, a printing plate, a coating liquid supply unit, and a relative movement unit. The mounting table places the substrate on the upper surface thereof. The printing plate is wound around the outer peripheral surface of the plate cylinder and holds the coating liquid on the surface according to the uneven pattern formed on the surface. The coating liquid supply unit supplies the coating liquid to the surface of the printing plate. The relative movement means moves the mounting table and the plate cylinder relative to each other while rotating the plate cylinder about the shaft core in a state where the upper surface of the substrate and the printing plate are brought close to or in contact with each other. The coating liquid supply unit includes a coating liquid supply roller and at least one nozzle. The coating liquid supply roller supplies the coating liquid held on the circumferential side surface to the surface of the printing plate by rotating the circumferential side surface close to or in contact with the printing plate. The nozzle discharges the coating liquid onto the circumferential side surface of the coating liquid supply roller, and supplies the coating liquid onto the circumferential side surface. The coating liquid supply unit includes at least two kinds of solvents having different drying speeds in the coating liquid, so that each of the patterns comes before the center of each of the patterns in the coating liquid on the substrate printed and applied in a pattern. The peripheral edge is dried, and the coating liquid is dried in a state where the fluidity of the coating liquid at the central portion is higher than that of the coating liquid at the peripheral edge.

  A fifteenth aspect of the invention is a method for manufacturing an organic EL element having an anode, a cathode, and an organic layer located between the anode and the cathode. The manufacturing method of an organic EL element includes the process of forming an organic layer. In the step of forming the organic layer, the organic layer is formed by printing and applying a coating liquid containing an organic EL material constituting the organic layer and at least two kinds of solvents having different drying rates on the substrate. The step of forming the organic layer includes a step of placing, a step of supplying and discharging, a step of supplying the coating solution to the surface of the printing plate, a step of transferring the coating solution, and a step of drying the coating solution. In the placing step, the substrate is placed on the surface of the placing table. In the discharging and supplying step, the coating liquid is discharged and supplied from at least one nozzle onto the circumferential side surface of the coating liquid supply roller. The step of supplying the coating liquid to the surface of the printing plate includes the surface of the printing plate wound around the outer peripheral surface of the plate cylinder and holding the coating liquid on the surface according to the uneven pattern formed on the surface, and the coating liquid By rotating the supply roller in proximity to or in contact with the circumferential side surface, the coating liquid discharged and supplied onto the circumferential side surface is supplied to the surface of the printing plate. The process of transferring the coating liquid is performed on the substrate by moving the mounting table and the plate cylinder relative to each other while rotating the plate cylinder around the shaft core in a state where the upper surface of the substrate and the printing plate are close to or in contact with each other. Transfer the coating solution. In the step of drying the coating liquid, the central part of each pattern in the coating liquid on the substrate printed and applied in a pattern according to the concavo-convex pattern is obtained by including at least two types of solvents having different drying speeds in the coating liquid. The periphery of each pattern is dried first, and the coating liquid is dried in a state where the fluidity of the coating liquid at the central portion is higher than the fluidity of the coating liquid at the peripheral edge.

  According to the first invention, the first solvent (high boiling point solvent) for ensuring fluidity of the organic EL material to be printed and the second solvent (low to medium boiling point solvent) for ensuring quick drying. Can be used to improve the film thickness uniformity when the organic EL material is applied by printing.

  According to the second aspect of the invention, by using a mixed solvent obtained by further mixing a third solvent (medium boiling point solvent) with the first solvent and the second solvent, film thickness uniformity when the organic EL material is applied by printing. Can be improved.

  According to the third to sixth inventions, at least one of the first solvent, the second solvent, and the third solvent has a predetermined concentration (first solvent: 35 to 70 wt%, second solvent: 5 to 15 wt%). , The third solvent: 25-50 wt%), the drying speed of the organic EL material can be adjusted to an intermediate speed. Thereby, the peripheral portion is dried before the central portion of the coating liquid printed and applied on the substrate, and the coating liquid is dried in a state where the fluidity of the central portion of the coating liquid is higher than that of the peripheral portion. Therefore, it is possible to improve the film thickness uniformity when the organic EL material is printed and applied.

  According to the thirteenth aspect, by supplying the coating liquid from the slit whose longitudinal direction is the axial direction, the coating liquid can be supplied uniformly to the circumferential side surface of the coating liquid supply roller.

  According to the fifteenth aspect of the invention, the drying speed of the organic EL material can be adjusted to an intermediate speed by including in the coating liquid at least two types of solvents having different drying speeds. Thus, the peripheral portion of each pattern is dried before the central portion of each of the patterns in the coating liquid that is printed and applied in a pattern on the substrate, and the flow of the central portion of the coating liquid from the peripheral portion of the coating liquid is performed. Since the coating liquid can be dried in a state where the property is high, the uniformity of the film thickness when the organic EL material is applied by printing can be improved.

  According to the coating apparatus of the present invention, it is possible to obtain the same effect as the above-described method for manufacturing an organic EL element.

  Below, the structure of the organic EL element which the manufacturing method and coating device of this invention make object are demonstrated, Then, the manufacturing method and coating device of the organic EL element which concern on this invention are demonstrated in more detail. Note that the scale of each member in the drawings shown in the following description may differ from the actual scale. In addition, although members such as electrode lead wires exist in the organic EL element, the description and illustration are omitted because they are not directly related to the description of the present invention.

(substrate)
The substrate used for the organic EL element may be any substrate that does not change when an electrode is formed and an organic layer is formed. For example, glass, plastic, a polymer film, a silicon substrate, or a laminate of these is used. It is done. Further, a plastic, a polymer film or the like that has been subjected to a low water permeability treatment can also be used. A commercially available substrate is available as the substrate, or can be manufactured by a known method.

(Electrode and light emitting layer)
As a basic structure of the organic EL element, at least one light emitting layer is provided between a pair of anodes and cathodes having at least an anode or a cathode that is transparent or translucent with light transmission. For the light emitting layer, a low molecular weight and / or high molecular weight organic light emitting material is used.

  In the organic EL element, the laminated components around the light emitting layer include, in addition to the cathode, the anode, and the light emitting layer, those provided between the cathode and the light emitting layer (cathode side interlayer), and between the anode and the light emitting layer. What is provided (anode side interlayer) is mentioned.

  Examples of the anode-side interlayer provided between the anode and the light emitting layer include a hole injection layer, a hole transport layer, and an electron block layer.

  The hole injection layer is a layer having a function of improving hole injection efficiency from the cathode. The hole transport layer is a layer having a function of improving hole injection from the hole injection layer or the hole transport layer closer to the anode. When the hole injection layer or the hole transport layer has a function of blocking electron transport, these layers may be referred to as an electron block layer. Having the function of blocking electron transport makes it possible, for example, to manufacture an element that allows only electron current to flow and to confirm the blocking effect by reducing the current value.

  Examples of the cathode side interlayer provided between the cathode and the light emitting layer include an electron injection layer, an electron transport layer, and a hole blocking layer.

  The electron injection layer is a layer having a function of improving electron injection efficiency from the cathode. The electron transport layer is a layer having a function of improving electron injection from the electron injection layer or the electron transport layer closer to the cathode. When the electron injection layer or the electron transport layer has a function of blocking hole transport, these layers may be referred to as a hole blocking layer. Having the function of blocking hole transport makes it possible, for example, to produce an element that allows only hole current to flow, and confirm the blocking effect by reducing the current value.

Various combinations of laminated structures around the light emitting layer as described above include a structure in which a hole transport layer is provided between the anode and the light emitting layer, a structure in which an electron transport layer is provided between the cathode and the light emitting layer, Examples include a configuration in which an electron transport layer is provided between the light emitting layer and a hole transport layer is provided between the anode and the light emitting layer. Specifically, the following structures a) to d) are exemplified.
a) Anode / light emitting layer / cathode b) Anode / hole transport layer / light emitting layer / cathode c) Anode / light emitting layer / electron transport layer / cathode d) Anode / hole transport layer / light emitting layer / electron transport layer / cathode Here, “/” indicates that each layer is laminated adjacently, and so on.

  In the above configuration, as described above, the light emitting layer is a layer having a function of emitting light, the hole transporting layer is a layer having a function of transporting holes, and the electron transporting layer is a function of transporting electrons. It is a layer which has. Note that the electron transport layer and the hole transport layer may be collectively referred to as a charge transport layer. Two or more light emitting layers, hole transport layers, and electron transport layers may be used independently. Further, among the charge transport layers provided adjacent to the electrodes, those having a function of improving the charge injection efficiency from the electrodes and having the effect of lowering the driving voltage of the element are particularly charge injection layers (hole injection layers). , Sometimes referred to as an electron injection layer).

  Furthermore, the charge injection layer or an insulating layer having a thickness of 2 nm or less may be provided adjacent to the electrode in order to improve adhesion with the electrode or improve charge injection from the electrode. In addition, a thin buffer layer may be inserted at the interface between the charge transport layer and the light emitting layer in order to improve adhesion at the interface or prevent mixing. The order and number of layers to be laminated and the thickness of each layer can be set as appropriate in consideration of light emission efficiency and element lifetime.

Moreover, as an organic EL element provided with a charge injection layer (electron injection layer, hole injection layer), an organic EL element provided with a charge injection layer adjacent to the cathode, and a charge injection layer provided adjacent to the anode. An organic EL element is mentioned. Specifically, the following structures e) to p) are exemplified.
e) Anode / charge injection layer / light emitting layer / cathode f) Anode / light emitting layer / charge injection layer / cathode g) Anode / charge injection layer / light emitting layer / charge injection layer / cathode h) Anode / charge injection layer / hole Transport layer / light emitting layer / cathode i) anode / hole transport layer / light emitting layer / charge injection layer / cathode j) anode / charge injection layer / hole transport layer / light emitting layer / charge injection layer / cathode k) anode / charge Injection layer / light emitting layer / charge transport layer / cathode l) anode / light emitting layer / electron transport layer / charge injection layer / cathode m) anode / charge injection layer / light emitting layer / electron transport layer / charge injection layer / cathode n) anode / Charge injection layer / hole transport layer / light emitting layer / charge transport layer / cathode o) anode / hole transport layer / light emitting layer / electron transport layer / charge injection layer / cathode p) anode / charge injection layer / hole transport Layer / light emitting layer / electron transport layer / charge injection layer / cathode

(anode)
For the anode, for example, as a transparent electrode or a semitransparent electrode, a metal oxide, metal sulfide or metal thin film with high electrical conductivity can be used, and a high transmittance can be suitably used. Are appropriately selected and used. Specifically, indium oxide, zinc oxide, tin oxide, indium tin oxide (ITO), indium zinc oxide (IZO), gold, platinum, silver, copper, etc. are used, and among these, ITO, IZO and tin oxide are preferable.

  Moreover, you may use organic transparent conductive films, such as polyaniline or its derivative (s), polythiophene or its derivative (s), as said anode. Further, a thin film made of a mixture containing at least one selected from the group consisting of materials used for the organic transparent conductive film, metal oxides, metal sulfides, metals, and carbon materials such as carbon nanotubes is used as an anode. It may be used.

  Furthermore, a material that reflects light may be used for the anode. As such a material, a metal, metal oxide, or metal sulfide having a work function of 3.0 eV or more is preferable.

  Examples of a method for producing the anode include a vacuum deposition method, a sputtering method, an ion plating method, and a plating method.

  The film thickness of the anode can be appropriately selected in consideration of light transmittance and electrical conductivity, and is, for example, 5 nm to 10 μm, preferably 10 nm to 1 μm, and more preferably 20 nm to 500 nm. is there.

(Anode side interlayer)
As described above, an anode-side interlayer such as a hole injection layer and a hole transport layer is laminated between the anode and the light emitting layer as necessary.

(Hole injection layer)
As described above, the hole injection layer can be provided between the anode and the hole transport layer or between the anode and the light emitting layer. As a material for forming the hole injection layer, a known material can be appropriately used, and there is no particular limitation. For example, phenylamine, starburst amine, phthalocyanine, hydrazone derivative, carbazole derivative, triazole derivative, imidazole derivative, oxadiazole derivative having amino group, vanadium oxide, tantalum oxide, tungsten oxide, molybdenum oxide, oxidation Examples thereof include oxides such as ruthenium and aluminum oxide, amorphous carbon, polyaniline, and polythiophene derivatives.

  The thickness of such a hole injection layer is preferably about 5 to 300 nm. If the thickness is less than 5 nm, production tends to be difficult. On the other hand, if it exceeds 300 nm, the driving voltage and the voltage applied to the hole injection layer tend to increase.

(Hole transport layer)
The material for forming the hole transport layer is not particularly limited. For example, N, N′-diphenyl-N, N′-di (3-methylphenyl) 4,4′-diaminobiphenyl (TPD), 4 , 4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPB) and other aromatic amine derivatives, polyvinylcarbazole or derivatives thereof, polysilane or derivatives thereof, aromatic amines in the side chain or main chain Polysiloxane derivative having pyrazole, pyrazoline derivative, arylamine derivative, stilbene derivative, triphenyldiamine derivative, polyaniline or derivative thereof, polythiophene or derivative thereof, polyarylamine or derivative thereof, polypyrrole or derivative thereof, poly (p-phenylene vinylene) Or its derivatives, or poly (2,5-thienylene vinylene) or a derivative thereof is exemplified.

  Among these, as a hole transport material used for the hole transport layer, polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof, a polysiloxane derivative having an aromatic amine compound group in a side chain or a main chain, polyaniline or a derivative thereof, Polymeric hole transport materials such as polythiophene or derivatives thereof, polyarylamine or derivatives thereof, poly (p-phenylene vinylene) or derivatives thereof, or poly (2,5-thienylene vinylene) or derivatives thereof are preferred, and more preferred Is polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof, and a polysiloxane derivative having an aromatic amine in the side chain or main chain. In the case of a low-molecular hole transport material, it is preferably used by being dispersed in a polymer binder.

  The thickness of the hole transport layer is not particularly limited, but can be appropriately changed according to the intended design, and is preferably about 1 to 1000 nm. If this thickness is less than the above lower limit, production tends to be difficult, or curing of hole transport cannot be obtained sufficiently. On the other hand, when the upper limit is exceeded, the driving voltage and the voltage applied to the hole transport layer tend to increase. As described above, the thickness of the hole transport layer is preferably 1-1000 nm, more preferably 2 nm-500 nm, and still more preferably 5 nm-200 nm.

(Organic light emitting layer)
The organic light emitting layer usually has an organic substance (low molecular compound and high molecular compound) that mainly emits fluorescence or phosphorescence. Further, a dopant material may be further included. Examples of the material for forming the organic light emitting layer that can be used in the present invention include the following dye-based materials, metal complex-based materials, polymer-based materials, and dopant materials.

  Examples of the dye-based material include cyclopentamine derivatives, tetraphenylbutadiene derivative compounds, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, pyrrole derivatives, and thiophene rings. Examples thereof include compounds, pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, trifumanylamine derivatives, oxadiazole dimers, and pyrazoline dimers.

  Examples of the metal complex materials include metal complexes having light emission from triplet excited states such as iridium complexes and platinum complexes, aluminum quinolinol complexes, benzoquinolinol beryllium complexes, benzoxazolyl zinc complexes, benzothiazole zinc complexes, Azomethylzinc complex, porphyrin zinc complex, europium complex, etc., center metal has Al, Zn, Be, etc. or rare earth metal such as Tb, Eu, Dy, etc., and ligand is oxadiazole, thiadiazole, phenylpyridine, phenyl Examples include metal complexes having benzimidazole, quinoline structure, and the like.

  As the above polymer materials, polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, the above dye bodies and metal complex light emitting materials are polymerized. And the like.

  Examples of materials that emit blue light among the above organic light emitting layer forming materials include distyrylarylene derivatives, oxadiazole derivatives, and polymers thereof, polyvinylcarbazole derivatives, polyparaphenylene derivatives, polyfluorene derivatives, and the like. . Of these, polymer materials such as polyvinyl carbazole derivatives, polyparaphenylene derivatives, and polyfluorene derivatives are preferred.

  Examples of the material that emits green light among the organic light emitting layer forming materials include quinacridone derivatives, coumarin derivatives, and polymers thereof, polyparaphenylene vinylene derivatives, polyfluorene derivatives, and the like. Of these, polymer materials such as polyparaphenylene vinylene derivatives and polyfluorene derivatives are preferred.

  Examples of the material that emits red light among the light emitting layer forming materials include coumarin derivatives, thiophene ring compounds, and polymers thereof, polyparaphenylene vinylene derivatives, polythiophene derivatives, and polyfluorene derivatives. Among these, polymer materials such as polyparaphenylene vinylene derivatives, polythiophene derivatives, polyfluorene derivatives and the like are preferable.

  A dopant can be added to the organic light emitting layer for the purpose of improving the light emission efficiency and changing the light emission wavelength. Examples of such dopants include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazolone derivatives, decacyclene, phenoxazone, and the like. In addition, the thickness of this organic light emitting layer is 2 nm-200 nm normally.

(Cathode side interlayer)
As described above, a cathode-side interlayer such as an electron injection layer and an electron transport layer is laminated between the light emitting layer and a cathode described later, if necessary.

(Electron transport layer)
As the material for forming the electron transport layer, known materials can be used, such as oxadiazole derivatives, anthraquinodimethane or derivatives thereof, benzoquinone or derivatives thereof, naphthoquinone or derivatives thereof, anthraquinones or derivatives thereof, tetracyanoanthraquinodi. Examples include methane or its derivatives, fluorenone derivatives, diphenyldicyanoethylene or its derivatives, diphenoquinone derivatives, or metal complexes of 8-hydroxyquinoline or its derivatives, polyquinoline or its derivatives, polyquinoxaline or its derivatives, polyfluorene or its derivatives, etc. The

  Of these, oxadiazole derivatives, benzoquinone or derivatives thereof, anthraquinones or derivatives thereof, or metal complexes of 8-hydroxyquinoline or derivatives thereof, polyquinoline or derivatives thereof, polyquinoxaline or derivatives thereof, polyfluorene or derivatives thereof are preferred, 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, benzoquinone, anthraquinone, tris (8-quinolinol) aluminum, and polyquinoline are more preferable.

(Electron injection layer)
As described above, the electron injection layer is provided between the electron transport layer and the cathode, or between the light emitting layer and the cathode. As a material for forming the electron injection layer, an alkali metal, an alkaline earth metal, an alloy including one or more of the above metals, an oxide, a halide, and a carbonate of the above metal, or the above substance, depending on the type of the light emitting layer And the like.

  Examples of the alkali metals or oxides, halides and carbonates thereof include lithium, sodium, potassium, rubidium, cesium, lithium oxide, lithium fluoride, sodium oxide, sodium fluoride, potassium oxide, potassium fluoride, and oxide. Examples include rubidium, rubidium fluoride, cesium oxide, cesium fluoride, and lithium carbonate.

  Examples of the alkaline earth metals or oxides, halides and carbonates thereof include magnesium, calcium, barium, strontium, magnesium oxide, magnesium fluoride, calcium oxide, calcium fluoride, calcium fluoride, barium oxide, fluorine. Barium fluoride, strontium oxide, strontium fluoride, magnesium carbonate and the like.

  Furthermore, a metal, a metal oxide, an organometallic compound doped with a metal salt, an organometallic complex compound, or a mixture thereof can also be used as a material for the electron injection layer.

  This electron injection layer may be a laminate of two or more layers. Specifically, Li / Ca etc. are mentioned. This electron injection layer is formed by vapor deposition, sputtering, printing, or the like. The thickness of the battery injection layer is preferably about 1 nm to 1 μm.

(cathode)
The material for the cathode is preferably a material having a small work function and easy electron injection into the light emitting layer and / or a material having a high electrical conductivity and / or a material having a high visible light reflectance. Specific examples of such a cathode material include metals, metal oxides, alloys, graphite or graphite intercalation compounds, and inorganic semiconductors such as ZnO (zinc oxide).

  As the metal, an alkali metal, an alkaline earth metal, a transition metal, a Group III-B metal, or the like can be used. Specific examples of these metals include lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin, and aluminum. , Scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium, and the like.

  Examples of the alloy include an alloy containing at least one of the above metals. Specifically, a magnesium-silver alloy, a magnesium-indium alloy, a magnesium-aluminum alloy, an indium-silver alloy, a lithium-aluminum alloy, Examples thereof include a lithium-magnesium alloy, a lithium-indium alloy, and a calcium-aluminum alloy.

  The cathode may be a transparent electrode or a semi-transparent electrode as necessary. Examples of the material include conductive oxides such as indium oxide, zinc oxide, tin oxide, ITO and IZO, polyaniline or derivatives thereof, polythiophene. Or electroconductive organic substances, such as its derivative (s), can be mentioned.

  Note that the cathode may have a laminated structure of two or more layers. Moreover, an electron injection layer may be used as a cathode.

  The thickness of the cathode can be appropriately selected in consideration of electric conductivity and durability, but is, for example, 10 nm to 10 μm, preferably 20 nm to 1 μm, and more preferably 50 nm to 500 nm. is there.

(Upper sealing film)
After the cathode is formed as described above, an upper sealing film is formed in order to protect the light emitting function part having the anode-light emitting layer-cathode as a basic structure. This upper sealing film usually has at least one inorganic layer and at least one organic layer. The number of stacked layers is determined as necessary, and basically, inorganic layers and organic layers are stacked alternately.

  When a plastic substrate is used as the substrate, the plastic substrate has higher gas and liquid permeability than a glass substrate, and the organic EL light emitting layer or the like may be encapsulated by the substrate and the upper sealing film. These display substances are easily oxidized and easily deteriorated by contact with water. Therefore, a lower sealing film having a high barrier property against gas and liquid is laminated on the plastic substrate, and then the light emitting function part is laminated on the lower sealing film. The lower sealing film is usually formed with the same configuration and the same material as the upper sealing film.

  Hereinafter, the manufacturing method of the organic EL element according to an embodiment of the present invention will be described in more detail.

(Anode formation process)
A substrate made of any of the aforementioned substrate materials is prepared. When a plastic substrate having high gas and liquid permeability is used, a lower sealing film is formed on the substrate as necessary.

  Next, an anode is pattern-formed on the prepared substrate using any of the anode materials described above. When this anode is used as a transparent electrode, as described above, a transparent electrode material such as ITO, IZO, tin oxide, zinc oxide, indium oxide, and zinc aluminum composite oxide is used. For example, in the case of using ITO, the electrode pattern is formed as a uniform deposited film on the substrate by a sputtering method, and then patterned into a line shape by photolithography.

(Partition forming process)
With reference to FIG. 1 and FIG. 2, an example of a partition formation process is demonstrated. FIG. 1 is a plan view showing an example of the organic EL element in a state where the partition wall 92 is formed. FIG. 2 is a cross-sectional configuration diagram of the organic EL element when the cross section SS shown in FIG. 1 is viewed from the T direction.

  As shown in FIGS. 1 and 2, after forming a first electrode (anode) 91 on a substrate 90, a stripe-shaped partition wall 92 is formed thereon. The partition wall 92 may be composed of only a number of first partition wall portions 92a having a stripe shape, or may be formed of a lattice-shaped second partition wall portion 92b in addition to the first partition wall portion 92a. . In the case of only the stripe-shaped first partition wall portion 92a, the exposed portion of the patterned first electrode 91 becomes the pixel region 93, and in the case of the first partition wall portion 92a and the second partition wall portion 92b, A rectangular plane defined by these becomes the pixel region 93. When the partition wall includes the first partition wall portion 92a and the second partition wall portion 92b, the height dimension of the striped first partition wall section 92a is set larger than the height dimension of the second partition wall section 92b. To do.

  The main role of the first partition wall portion 92a is to separate the plurality of first electrodes 91 arranged in the stripe-shaped concave portions from the first electrodes 91 in the adjacent concave portions and to prevent color mixing between adjacent pixels. is there. Therefore, the height dimension of the 1st partition part 92a is set relatively high. On the other hand, the role of the second partition wall 92b is only to insulate the pixel regions distributed in the stripe direction of the first electrode 91 (electrical insulating layer), and has no role in preventing color mixing. Therefore, it may be formed somewhat thicker than the total thickness of laminated films such as an interlayer and an organic light emitting layer formed on the pixel region 93. From such a reference, the height dimension of the first partition wall 92a is preferably set to 2 to 3 μm, and the height dimension of the second partition wall 92b is preferably set to 0.1 to 0.2 μm. Note that the second partition wall portion 92b can be omitted depending on the electrical conductivity of the organic material.

A method for manufacturing the partition wall 92 having the above structure is not particularly limited, but for example, it can be manufactured as follows. First, an insulating film having a thickness of 0.1 to 0.2 μm made of an inorganic insulating material such as SiO ₂ or SiN is formed by a known method such as a plasma CVD method or a sputtering method, and then formed into a lattice shape by photography and etching. Pattern. Next, a photoresist layer having a thickness of 2 to 3 μm is formed on the lattice-like insulating film, and this photoresist layer is exposed through a stripe-shaped mask, and the plurality of stripe-shaped first electrodes 91 are formed. Development is performed so that the resist layer remains only, and heat curing is performed. As described above, the resist layer patterned in the stripe form constitutes the first partition wall portion 92a, and the insulating film which is formed before and is not covered with the first partition wall portion 92a is the second partition wall portion 92b. Configure.

  The photosensitive material (photoresist composition) can be applied by a coating method using a spin coater, bar coater, roll coater, die coater, gravure coater, slit coater or the like.

  The insulating photosensitive material forming the partition wall 92 may be either a positive resist or a negative resist. It is important that the partition wall 92 be insulative. If the partition wall 92 is not insulative, current flows between the first electrodes 91 (anodes) defined by the partition wall 92, resulting in display defects. Resulting in.

  As the insulating photosensitive material for constituting the partition wall 92, specifically, polyimide, acrylic resin, and novolak resin photosensitive compounds can be used. This photosensitive material may contain a light-shielding material for the purpose of improving the display quality of the organic EL element.

  In order to impart ink repellency to the surface of the partition wall 92, an ink repellant substance may be added to the photosensitive material for forming the partition wall. Alternatively, after the partition wall 92 is formed, the surface of the partition wall 92 may be provided with ink repellency by coating the surface with an ink-repellent substance. This ink repellency is preferably repellant both for the ink for an interlayer described later and for the ink for an organic light emitting layer.

  As a substance used when an ink repellent substance is added to the photosensitive material, a silicon compound or a fluorine-containing compound is used. These ink repellent compounds exhibit ink repellency for both organic light-emitting inks (coating liquids) used for forming an organic light-emitting layer described later and organic material inks (coating liquids) for interlayers such as a hole transport layer. Therefore, it can be suitably used.

As a method for forming an ink-repellent film on the surface of the partition wall 92 after forming the partition wall 92, a method of applying a coating liquid containing an ink-repellent component to the surface of the partition wall 92, or vaporizing the ink-repellent component to partition the partition wall. The method of depositing on the surface of 92, the method of modifying the surface by substituting the functional group of the organic material of the surface of the partition wall 92 with fluorine, etc. can be mentioned. As the latter deposition method by the vapor phase method, specifically, the CF ₄ gas is converted into plasma by using a vacuum plasma apparatus and a fluorine component is allowed to act on the surface of the partition wall 92, thereby making the surface of the partition wall 92 liquid-repellent. The method of giving is mentioned.

(Anode-side interlayer formation process)
After the formation of the partition wall 92, an organic material layer (anode-side interlayer) such as the above-described hole transport layer is formed as necessary.

  Although there is no restriction | limiting in particular as a film-forming method of an anode side interlayer, The method by the film-forming from a mixed solution with a polymer binder is illustrated in a low molecular material. In the case of a polymer material, a method by film formation from a solution is exemplified.

  The solvent used for film formation from a solution is not particularly limited as long as it dissolves the above-mentioned anode side interlayer material. Examples of such solvents include chloro solvents such as chloroform, methylene chloride, dichloroethane, ether solvents such as tetrahydrofuran, aromatic hydrocarbon solvents such as toluene and xylene, ketone solvents such as acetone and methyl ethyl ketone, ethyl acetate, butyl acetate, An ester solvent such as ethyl cellosolve acetate is exemplified, and a mixed solvent of a first solvent and a second solvent described later, or a mixed solvent of first to third solvents is preferable.

  As the polymer binder to be mixed, those not extremely disturbing charge transport are preferable, and those not strongly absorbing visible light are suitably used. Examples of such a polymer binder include polycarbonate, polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, polysiloxane and the like.

  The organic light emitting ink is prepared by dissolving or stably dispersing an organic light emitting material in a solvent. Examples of the solvent for dissolving or dispersing the organic light emitting material include toluene, xylene, acetone, anisole, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and the like, or a mixed solvent thereof. Or a mixed solvent of the first to third solvents.

  In addition, you may add surfactant, antioxidant, a viscosity modifier, a ultraviolet absorber, etc. to organic luminescent ink as needed.

(Cathode-side interlayer formation process)
After the formation of the organic light emitting layer, a cathode-side interlayer such as an electron transport layer or an electron injection layer is formed as necessary. The method for forming this cathode side interlayer is not particularly limited in the case of an electron transport layer, but for low molecular weight electron transport materials, a vacuum deposition method from powder or a method by film formation from a solution or a molten state is exemplified. In the polymer electron transport material, a method by film formation from a solution or a molten state is exemplified. In film formation from a solution or a molten state, a polymer binder may be used in combination. As a method for forming an electron transport layer from a solution, a film formation method similar to the method for forming a hole transport layer from a solution described above can be used. In the case of an electron injection layer, it is formed using a vapor deposition method, a sputtering method, a printing method, or the like.

(Cathode formation process)
The cathode is formed by using any of the materials described above by a vacuum deposition method, a sputtering method, a CVD method, an ion plating method, a laser ablation method, a laminating method for press-bonding a metal thin film, or the like.

  After the cathode is formed as described above, an upper sealing film is formed in order to protect the light emitting function part having the anode-light emitting layer-cathode as a basic structure. The upper sealing film is composed of at least one inorganic layer and at least one organic layer as necessary. The number of these layers is determined as necessary. Basically, the inorganic layers and the organic layers are alternately stacked.

  Next, with reference to FIG. 3, the coating apparatus 1 which concerns on one Embodiment of this invention is demonstrated. In order to make the description concrete, the following description will be given using an example in which the coating apparatus 1 is applied to a coating apparatus that manufactures an organic EL device that uses a solution in which an organic EL material is dissolved as a coating liquid. Note that the organic EL material in this specification is a material for forming an organic layer (a layer containing an organic substance among the light emitting layer, the charge transport layer, the charge injection layer, and the like described above). Among the materials to be formed, the material is soluble in a solvent. The coating apparatus 1 prints and coats a coating solution containing an organic EL material in a predetermined pattern shape on an object to be coated (for example, a glass substrate on which an ITO thin film is formed) placed on a stage. To produce an organic EL device. In addition, the coating apparatus 1 uses a plurality of types of coating liquids containing an organic EL material as described above, and a polymer material used as an organic EL material for forming a light emitting layer as a representative thereof (hereinafter referred to as a polymer organic EL material) Will be described as an example in which a solution in which is dissolved) is used as a coating solution. FIG. 3 is a perspective view illustrating a schematic configuration of a main part of the coating apparatus 1.

  In FIG. 3, the coating apparatus 1 generally includes a plate cylinder 11 around which a printing plate 12 is wound, a coating liquid supply unit 20, a substrate transport mechanism 50, and a lifting mechanism 60. In FIG. 3, as a configuration of the coating liquid supply unit 20, a coating liquid supply roller 21, a slit nozzle 22, a first motor 28, and a second motor 29 are illustrated. The substrate transport mechanism 50 includes a base 51, a pair of transport guide members 52, a transport drive unit 53, and a transport table 54. The elevating mechanism 60 includes an elevating table 61, a pair of elevating guide members 62, an elevating drive unit 63, and a support side plate 64.

  The pair of transport guide members 52 are fixed to the upper surface of the base 51 so as to extend in a horizontal direction perpendicular to the axis of the plate cylinder 11. The transport driving unit 53 is configured by, for example, a linear motor whose driving direction is the extending direction of the pair of transport guide members 52. The transfer table 54 places a substrate P, which is an example of an object to be coated, on the upper surface thereof. The transport table 54 is connected to the pair of transport guide members 52 and the transport drive unit 53, receives the driving force of the transport drive unit 53, and moves the substrate P in the horizontal direction perpendicular to the axis of the plate cylinder 11. Is moved back and forth.

  The support side plates 64 are configured as a pair of left and right with respect to the lifting table 61 and are fixed to the lifting table 61, respectively. On the other hand, on the base 51, a pair of elevating guide members 62 are extended in the vertical direction. The raising / lowering drive part 63 makes the extending direction of the raising / lowering guide member 62 a drive direction, for example, is comprised by the ball screw provided in the said extending direction, and the motor which rotates the said ball screw. A plate cylinder 11 and a coating liquid supply unit 20 are mounted on the lifting table 61. The support side plate 64 fixed to the elevating table 61 is connected to the elevating guide member 62 and the elevating drive unit 63, and can be moved up and down along the elevating guide member 62 by receiving a driving force from the elevating drive unit 63. It becomes. Therefore, the plate cylinder 11 and the coating liquid supply unit 20 can move up and down together with the lifting table 61 by receiving the driving force of the lifting drive unit 63. Moreover, the 1st motor 28 and the 2nd motor 29 raise / lower the slit nozzle 22 according to those drive.

  Next, basic configurations of the plate cylinder 11 and the coating liquid supply unit 20 will be described with reference to FIG. FIG. 4 is a schematic diagram showing a main part of the coating apparatus 1.

  In FIG. 4, a printing plate 12 is wound around and fixed to the outer circumferential surface of the plate cylinder 11, and its axis is disposed in the horizontal direction. On the surface of the printing plate 12, a pattern of the coating liquid to be transferred to the substrate P is formed in a convex shape. For example, the printing plate 12 is a flexographic plate and is made of a flexible material such as a photosensitive material (for example, an ultraviolet curable resin).

  The plate cylinder 11 is provided so as to be rotatable in the direction of the arrow A in the figure with the printing plate 12 supported on the circumferential surface, and receives a driving force from a rotation driving mechanism (not shown) at a predetermined rotation speed. Rotate. A transport table 54 is disposed in the lower space of the plate cylinder 11. As described above, the substrate P is placed on the upper surface of the transfer table 54 so as to be horizontally movable, and receives the driving force from the transfer drive unit 53 and moves horizontally at a predetermined moving speed. The transport table 54 passes through the lower space of the plate cylinder 11 by moving horizontally in the direction of arrow B in the figure. At this time, the elevating table 61 is set so that the gap generated between the substrate P previously placed on the transport table 54 and the printing plate 12 fixed to the plate cylinder 11 or the amount of pressing against the substrate P is within a predetermined range. The position of (see FIG. 3) is adjusted.

  A control unit (not shown) of the coating apparatus 1 controls the transport driving unit 53 to horizontally move the transport table 54 on which the substrate P is placed in the direction of the arrow B in the drawing so as to pass through the lower space of the plate cylinder 11. At this time, the plate cylinder 11 is rotated in the direction of the arrow A in the figure so as not to cause a difference in speed according to the horizontal movement speed of the transport table 54 by controlling the rotation driving mechanism. As a result, the coating liquid (solution containing the polymer organic EL material) supplied to the printing plate 12 while the substrate P placed on the transport table 54 and the printing plate 12 face each other while maintaining a predetermined gap. Transferred to the substrate P.

  The coating liquid supply roller 21 is arranged such that its axis is parallel to the axis of the plate cylinder 11. For example, the coating liquid supply roller 21 is configured by a flat roller having a smooth circumferential surface. The coating liquid supply roller 21 rotates in opposite directions (in the direction of the arrow C in the figure) while the circumferential surface thereof is in contact with the printing plate 12 wound around the plate cylinder 11, so that the surface of the printing plate 12. Is supplied with a coating solution (a solution containing a polymer organic EL material).

  The coating liquid supply roller 21 is pivotally supported by a pair of left and right roller support portions. The plate cylinder 11 is also pivotally supported by a pair of left and right plate cylinder supports. The roller support portion is configured to be able to contact and separate from the plate cylinder support portion.

  The coating liquid supply unit 20 includes a cleaning mechanism 23 and a supply source 24 in addition to the configuration shown in FIG. The supply source 24 stores a coating liquid containing a polymer organic EL material to be printed and applied to the substrate P, and supplies a coating liquid containing a predetermined amount of the polymer organic EL material to the slit nozzle 22. The slit nozzle 22 has a slit whose longitudinal direction is the axial direction of the coating liquid supply roller 21. The slit nozzle 22 discharges the coating liquid containing the polymer organic EL material supplied from the supply source 24 onto the circumferential surface of the coating liquid supply roller 21 from the slit at a predetermined flow rate. A thin film of a coating solution containing a polymer organic EL material is formed thereon. The slit of the slit nozzle 22 is spaced from the circumferential surface of the coating liquid supply roller 21 by a predetermined distance, and the distance is adjusted by driving the first motor 28 and the second motor 29, respectively. Then, the circumferential surface of the coating liquid supply roller 21 after the coating liquid containing the polymer organic EL material is supplied to the surface of the printing plate 12 is cleaned by the cleaning mechanism 23. A structural example of the cleaning mechanism 23 will be described later. Further, the surface of the printing plate 12 after the coating liquid containing the polymer organic EL material is transferred to the substrate P may be cleaned by a cleaning mechanism (not shown).

  Thus, in the coating apparatus 1, the coating liquid containing the polymer organic EL material is supplied from the slit nozzle 22 to the surface of the coating liquid supply roller 21, and the surface of the coating liquid supply roller 21 contains the polymer organic EL material. A thin film of coating solution is formed. Then, the coating liquid containing the polymer organic EL material is transferred to a convex pattern formed on the printing plate 12, and a thin film pattern of the coating liquid containing the polymer organic EL material is formed on the printing plate 12. . A thin film pattern of a coating solution containing a polymer organic EL material formed on the printing plate 12 is printed on the substrate P. For example, by forming a fine stripe-shaped convex pattern on the printing plate 12, the coating liquid containing the polymer organic EL material can be applied onto the substrate P in fine stripes.

  Next, a configuration example of the cleaning mechanism 23 will be described with reference to FIG. FIG. 5 is a schematic diagram illustrating an example of the cleaning mechanism 23.

  In FIG. 5, when the coating liquid containing the polymer organic EL material remains on the surface of the coating liquid supply roller 21, the coating liquid containing the polymer organic EL material is further supplied from the slit nozzle 22. In this case, the film thickness of the coating liquid containing the polymer organic EL material on the surface of the coating liquid supply roller 21 increases and becomes non-uniform. As a result, the coating liquid containing the polymer organic EL material having poor uniformity is formed on the substrate P. Will be printed on. In order to prevent such nonuniformity of the coating liquid containing the polymer organic EL material, the surface of the coating liquid supply roller 21 after supplying the coating liquid containing the polymer organic EL material to the surface of the printing plate 12 is: Cleaning is performed by the cleaning mechanism 23. The cleaning mechanism 23 includes a cleaning liquid container 231, a first blade 232, a second blade 233, and a recovery conduit 234.

  The first blade 232 scrapes off the coating liquid containing the main polymer organic EL material remaining on the surface of the coating liquid supply roller 21 after the coating liquid containing the polymer organic EL material is supplied to the surface of the printing plate 12. . The recovery conduit 234 recovers the coating liquid containing the polymer organic EL material scraped off by the first blade 232. Before the coating liquid containing the polymer organic EL material is scraped off by the first blade 232, the coating liquid containing the polymer organic EL material is applied to the surface of the coating liquid supply roller 21 after being supplied to the surface of the printing plate 12. A rinse solution (for example, a solvent for a coating solution containing a polymer organic EL material) may be supplied. In this case, the first blade 232 scrapes off the coating liquid containing the main polymer organic EL material remaining on the surface of the coating liquid supply roller 21 together with the rinsing liquid, and the recovery pipe 234 is formed by the first blade 232. The coating liquid and the rinse liquid containing the polymer organic EL material scraped off are collected. By supplying the rinse liquid in this way, it is possible to prevent the coating liquid containing the remaining polymer organic EL material from solidifying.

  The cleaning liquid container 231 is a container having an open upper surface, and stores a cleaning liquid C (for example, a solvent for a coating liquid containing a polymer organic EL material) therein. The cleaning liquid container 231 is a part of the surface of the coating liquid supply roller 21 (specifically, the lowermost surface after the coating liquid containing the main polymer organic EL material is scraped off by the first blade 232. ) Is immersed in the cleaning liquid C. Then, the second blade 233 scrapes off the cleaning liquid C remaining on the surface of the coating liquid supply roller 21 after being immersed in the cleaning liquid C.

  Next, the drying speed of the coating liquid in the coating apparatus 1 according to this embodiment will be described. As described above, when the coating liquid containing the polymer organic EL material is applied in fine stripes by the printing method, the coating liquid containing the ink-like polymer organic EL material is printed and applied in a wet state. Therefore, the cross-sectional shape of the polymer organic EL material that has been applied by printing is a so-called “kamaboko” shape due to the correlation between the wet state of the wet state and the base film in the coating liquid containing the polymer organic EL material. (See FIG. 9).

  And when the drying speed of the coating liquid containing the polymer organic EL material applied by printing is slow, the solvent volatilizes over the entire surface of the coating liquid containing the polymer organic EL material. Dry while maintaining the cross-sectional shape (ie, “kamaboko” shape). On the other hand, when the drying speed of the coating liquid containing the polymer organic EL material applied by printing is high, drying of the coating liquid containing the polymer organic EL material may start during the print coating process. In addition, when the drying speed of the coating liquid containing the polymer organic EL material applied by printing is high, the leveling time for smoothing / homogenizing the coating surface is shortened, and the polymer organic EL material is included immediately after coating printing. Since the fluidity of the coating liquid is lowered, there arises a problem that the film thickness uniformity is lowered and a transparent film cannot be formed.

  In this embodiment, in order to solve these problems, the drying speed of the coating liquid containing the polymer organic EL material that has been printed and applied is adjusted to an intermediate speed. When the drying speed is adjusted to an intermediate speed, an appropriate leveling time can be secured, that is, the fluidity of the coating liquid containing the polymer organic EL material can be maintained. The shape can be approximated to a rectangle. For example, as shown in the left diagram of FIG. 6, the periphery of each of the stripes in the polymer organic EL material separately applied in a fine stripe shape has a surrounding atmosphere compared to the vicinity of the center of each of the stripes. The solvent concentration is low, and therefore, the vicinity of the peripheral portion has a fast evaporation of the solvent and the drying is fast, whereas the vicinity of the central portion has a high concentration of the solvent in the surrounding atmosphere, so the evaporation of the solvent is slow and the drying is also slow. It is presumed that the state is rich in fluidity as compared with the peripheral portion. Due to the difference in the dry state, the coating liquid containing the polymer organic EL material applied in fine stripes is different from the coating liquid containing the wet polymer organic EL material in the central portion for each stripe. It flows so as to be drawn to the periphery. Thus, since the coating liquid containing the polymer organic EL material is dried, the film thickness of the peripheral portion is increased immediately after the printing application, and the film thickness of the central portion is decreased. It progresses in the direction of uniformization as a film thickness (state of the right figure of FIG. 6).

  In this embodiment, the drying speed of the coating liquid containing the polymer organic EL material that has been printed and applied is adjusted to an intermediate speed according to the solvent used in the polymer organic EL material and the mixing ratio thereof. For example, as a solvent used in a coating solution containing a polymer organic EL material, a high boiling point solvent having a vapor pressure of 100 Pa (Pascal) or less at 20 ° C. (for example, tetralin, cyclohexylbenzene, etc .; hereinafter referred to as a first solvent) A low to medium boiling solvent having a vapor pressure of 500 Pa or higher at 20 ° C. (hereinafter referred to as a second solvent), and a medium boiling solvent having a vapor pressure of 100 Pa to 500 Pa at 20 ° C. (for example, anisole, mesitylene, etc .; Described as a third solvent). In this embodiment, as a solvent of the coating liquid containing the polymer organic EL material, a mixed solvent in which the first solvent is combined with the second solvent, or a mixed solvent in which the first solvent is combined with the second solvent and the third solvent. Using, the drying speed of the coating liquid containing the polymer organic EL material is adjusted to an intermediate speed.

  For example, as shown in FIG. 7, a mixed solvent in which the first solvent is 35 to 70 wt% (weight percent), the second solvent is 5 to 15 wt%, and the third solvent is 25 to 50 wt% is used. Thus, the drying speed of the coating liquid containing the polymer organic EL material is adjusted to an intermediate speed. Then, by mixing the mixed solvent and the polymer organic EL material in advance, the polymer organic EL material is converted into ink and charged into the supply source 24 (see FIG. 4). Then, the coating apparatus 1 prints and applies the coating liquid containing the polymer organic EL material containing the mixed solvent onto the substrate P. In addition, the ratio of the organic EL material in the coating liquid is usually about 0.01 to 5 wt%. Moreover, it is preferable that a 1st solvent is 35-65 wt%.

  A polymer organic EL material containing such a mixed solvent is printed on the substrate P by the coating apparatus 1 and naturally dried in a clean room. As a result, a cross-sectional shape of the polymer organic EL material as shown in FIG. 8 is obtained. It was. As shown in FIG. 8, the cross-sectional shape of the polymer organic EL material has a trapezoidal shape that is nearly symmetrical, and the film thickness on the upper surface is made uniform even when compared with the cross-sectional shape shown in FIG. 9. It is clear that

  As described above, in the coating apparatus 1 according to the present embodiment, the first solvent (high boiling point solvent) for securing the fluidity of the coating liquid containing the polymer organic EL material to be printed and coated and the quick drying property are secured. By using a mixed solvent in which the second solvent (low to medium boiling point solvent) is mixed, it is possible to improve the film thickness uniformity when the polymer organic EL material is applied by printing.

  In the above-described embodiment, the example in which the coating apparatus 1 prints and applies the coating liquid containing the polymer organic EL material forming the light emitting layer onto the substrate P is used. However, the polymer organic EL material that emits red light, green Needless to say, a coating liquid containing a light emitting polymer organic EL material and a blue light emitting polymer organic EL material can be printed and applied, respectively. In addition, the coating apparatus of the present invention includes a coating solution containing, in addition to the organic light emitting layer material, other organic EL materials such as a hole transport layer material, a hole injection layer material, an electron transport layer material, and an electron injection layer material. Can also be used for printing and coating.

  Specifically, in the case where the coating apparatus 1 in the above-described embodiment prints and applies a coating liquid containing a polymer organic EL material that emits red light among red, green, and blue light emission, this coating process includes organic EL. This is an intermediate process for manufacturing a device. When manufacturing organic EL devices, hole injection layer material printing coating, hole transporting material (for example, PEDOT etc.) printing coating, red light emitting polymer organic EL material printing coating, green light emitting polymer organic EL material printing coating There are coating processes such as blue light emitting polymer organic EL material printing coating, electron transport material printing coating, electron injection layer material printing coating, etc., but the coating apparatus of the present invention can be used in any printing coating process.

  Moreover, in embodiment mentioned above, although the glass substrate was used as an example of a to-be-coated body, another member can also be used as a to-be-coated body. For example, a flexible substrate made of polyethylene terephthalate (PET), polycarbonate (PC), or the like may be used as the coating object of the coating apparatus 1.

  In the above description, the printing cylinder 11 is rotated while horizontally moving the conveyance table 54 on which the substrate P is placed, and printing is applied. However, the conveyance table 54 is fixed and the plate cylinder 11 itself is placed in the horizontal direction. It may be rotated while moving in the horizontal direction opposite to the moving direction. Needless to say, if at least one of the plate cylinder 11 and the transport table 54 moves relatively in the horizontal direction, the same printing application is possible.

  In the embodiment described above, the slit nozzle 22 having a slit whose longitudinal direction is the axial direction of the coating liquid supply roller 21 is used as a nozzle for supplying the coating liquid to the surface of the coating liquid supply roller 21. However, other nozzles may be used. A nozzle having a plurality of discharge ports is used as long as it can supply a coating liquid containing a polymer organic EL material at a predetermined flow rate along the axial direction of the coating liquid supply roller 21 to the surface of the coating liquid supply roller 21. It doesn't matter. For example, a nozzle in which a large number of discharge ports are arranged in the axial direction of the coating liquid supply roller 21 may be used.

  INDUSTRIAL APPLICABILITY The organic EL device manufacturing method and coating apparatus according to the present invention can improve the film thickness uniformity when a coating liquid containing an organic EL material is printed and applied, and is used for lighting, displays, and the like. It is useful as a method and apparatus for producing

The top view which shows an example of the board | substrate for organic EL elements of the state in which the partition 92 was formed 1 is a cross-sectional configuration diagram of an organic EL element substrate when the cross section SS shown in FIG. 1 is viewed from the T direction. The perspective view which shows the principal part schematic structure of the coating device 1 which concerns on one Embodiment of this invention. FIG. 3 is a schematic diagram showing a main part of the coating apparatus 1 of the coating apparatus 1 of FIG. Schematic diagram showing an example of the cleaning mechanism 23 of FIG. Explanatory drawing for demonstrating an example of the film thickness change of the polymeric organic electroluminescent material by which printing application | coating was carried out The figure which shows the weight percent concentration example which mixes a 1st solvent, a 2nd solvent, and a 3rd solvent. The figure which shows an example of the cross-sectional shape of the polymer organic electroluminescent material printed and apply | coated with the coating device 1 of FIG. The figure which shows an example of the cross-sectional shape of the polymer organic electroluminescent material printed and applied with the conventional coating device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Coating apparatus 11 ... Plate cylinder 12 ... Printing plate 20 ... Coating liquid supply part 21 ... Coating liquid supply roller 22 ... Slit nozzle 23 ... Cleaning mechanism 231 ... Cleaning liquid container 232 ... 1st blade 233 ... 2nd blade 234 ... Collection pipe Path 24 ... Supply source 28 ... First motor 29 ... Second motor 50 ... Substrate transport mechanism 51 ... Base 52 ... Transport guide member 53 ... Transport drive unit 54 ... Transport table 60 ... Elevating mechanism 61 ... Elevating table 62 ... Elevating guide Member 63 ... Elevating drive unit 64 ... Support side plate 90 ... Substrate 91 ... First electrode 92 ... Partition wall 93 ... Pixel region

Claims (15)

A method for producing an organic EL device having an anode, a cathode, and an organic layer located between the anode and the cathode,
A coating liquid containing an organic EL material constituting the organic layer, a first solvent having a vapor pressure at 20 ° C. of 100 Pa or less, and a second solvent having a vapor pressure at 20 ° C. of 500 Pa or more is printed on the substrate. Including the step of forming the organic layer by coating,
The step of forming the organic layer includes
Placing the substrate on the top surface of the mounting table;
A step of discharging and supplying the coating liquid from at least one nozzle onto the circumferential side surface of the coating liquid supply roller;
The surface of the printing plate that is wound around the outer peripheral surface of the plate cylinder and holds the coating liquid on the surface according to the concavo-convex pattern formed on the surface thereof, and the circumferential side surface of the coating liquid supply roller are close to each other or Supplying the coating liquid discharged and supplied onto the circumferential side surface to the surface of the printing plate by rotating in contact with the surface; and
An organic EL element including a step of relatively moving the mounting table and the plate cylinder while rotating the plate cylinder about an axis while the substrate surface and the printing plate are in proximity to or in contact with each other Manufacturing method.   The said coating liquid is a manufacturing method of the organic EL element of Claim 1 which further contains the 3rd solvent whose vapor pressure in 20 degreeC is 100 Pa-500 Pa.   The said coating liquid is a manufacturing method of the organic EL element of Claim 1 or 2 containing the said 1st solvent within the range of 35-70 wt%.   The said coating liquid is a manufacturing method of the organic EL element as described in any one of Claims 1 thru | or 3 which contains the said 2nd solvent in 5-15 wt%.   The said coating liquid is a manufacturing method of the organic EL element of Claim 2 containing the said 3rd solvent within the range of 25-50 wt%. The coating liquid is
Containing the first solvent in a range of 35 to 70 wt%;
The manufacturing method of the organic EL element of Claim 5 which contains the said 2nd solvent in 5-15 wt%. A coating apparatus that prints and applies a coating liquid containing an organic EL material on a substrate,
A mounting table on which the substrate is mounted;
Plate cylinder,
A printing plate that is wound around the outer peripheral surface of the plate cylinder and holds the coating liquid on the surface according to the uneven pattern formed on the surface;
A coating solution supply section for supplying the coating solution to the surface of the printing plate;
Relative movement means for relatively moving the mounting table and the plate cylinder while rotating the plate cylinder around an axis while the top surface of the substrate and the printing plate are in proximity to or in contact with each other,
The coating liquid supply unit
A coating liquid supply roller for supplying the coating liquid held on the circumferential side surface to the surface of the printing plate by rotating the circumferential side surface close to or in contact with the printing plate;
At least one nozzle that discharges the coating liquid onto a circumferential side surface of the coating liquid supply roller and supplies the coating liquid onto the circumferential side surface;
The coating solution contains at least the organic EL material, a first solvent having a vapor pressure at 20 ° C. of 100 Pa or less, and a second solvent having a vapor pressure at 20 ° C. of 500 Pa or more.   The said coating liquid is a coating device of Claim 7 which further contains the 3rd solvent whose vapor pressure in 20 degreeC is 100 Pa-500 Pa.   The coating apparatus according to claim 7 or 8, wherein the coating liquid contains the first solvent in a range of 35 to 70 wt%.   The coating apparatus according to claim 7, wherein the coating liquid contains the second solvent in a range of 5 to 15 wt%.   The coating apparatus according to claim 8, wherein the coating solution contains the third solvent in a range of 25 to 50 wt%. The coating liquid is
Containing the first solvent in a range of 35 to 70 wt%;
The coating apparatus according to claim 11, comprising the second solvent in a range of 5 to 15 wt%.   The coating device according to claim 7, wherein the nozzle is one slit nozzle having a slit facing the circumferential side surface with the axial direction of the coating liquid supply roller as a longitudinal direction. A coating apparatus that prints and applies a coating liquid containing an organic EL material on a substrate,
A mounting table on which the substrate is mounted;
Plate cylinder,
A printing plate that is wound around the outer peripheral surface of the plate cylinder and holds the coating liquid on the surface according to the uneven pattern formed on the surface;
A coating solution supply section for supplying the coating solution to the surface of the printing plate;
Relative movement means for relatively moving the mounting table and the plate cylinder while rotating the plate cylinder around an axis while the top surface of the substrate and the printing plate are in proximity to or in contact with each other,
The coating liquid supply unit
A coating liquid supply roller for supplying the coating liquid held on the circumferential side surface to the surface of the printing plate by rotating the circumferential side surface close to or in contact with the printing plate;
At least one nozzle that discharges the coating liquid onto a circumferential side surface of the coating liquid supply roller and supplies the coating liquid onto the circumferential side surface;
The coating liquid supply unit includes at least two kinds of solvents having different drying speeds in the coating liquid, so that the coating liquid on the substrate printed and applied in the pattern form is ahead of the center of each of the patterns. The coating apparatus which dries the peripheral part of each said pattern, and dries a coating liquid in the state whose fluidity | liquidity of the coating liquid of the said center part is higher than the coating liquid of the said peripheral part. A method for producing an organic EL device having an anode, a cathode, and an organic layer located between the anode and the cathode,
Including the step of forming the organic layer by printing and applying a coating liquid containing an organic EL material constituting the organic layer and at least two types of solvents having different drying rates on a substrate,
The step of forming the organic layer includes
Placing the substrate on the surface of the mounting table;
A step of discharging and supplying the coating liquid from at least one nozzle onto the circumferential side surface of the coating liquid supply roller;
The surface of the printing plate that is wound around the outer peripheral surface of the plate cylinder and holds the coating liquid on the surface according to the concavo-convex pattern formed on the surface, and the circumferential side surface of the coating liquid supply roller are close to each other or contacted. Supplying the coating liquid discharged and supplied onto the circumferential side surface to the surface of the printing plate by rotating in contact with the surface; and
In a state where the upper surface of the substrate and the printing plate are close to or in contact with each other, the platen and the plate cylinder are moved relative to each other while rotating the plate cylinder around an axis, and the coating is applied onto the substrate. A step of transferring the liquid;
By including at least two kinds of solvents having different drying speeds in the coating liquid, each of the patterns is more than the center of each of the patterns in the coating liquid on the substrate printed and applied in a pattern according to the uneven pattern. And drying the coating liquid in a state in which the fluidity of the coating liquid in the central part is higher than the fluidity of the coating liquid in the peripheral part.

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