JP2004134150A - Manufacturing method of organic el element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new manufacturing method of an organic EL (electroluminescent) element which maintains advantageous points of accuracy of a pattern in a conventional photolithography method and utilizes virtues of manufacturing efficiency in an inkjet method. <P>SOLUTION: The method comprises steps of forming a recessed portion 4A in the usual way by forming a photoresist layer 3 on a first electrode layer 2 of a substrate 1; and forming a light-emitting layer by laminating a buffer layer 7A, an organic phosphor layer 8A or the like in the recessed portion 4A. The method can manufacture an organic EL element able to perform a full color display by repeating the steps while varying a forming position of the recessed portion 4A. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a new method for manufacturing an organic EL device, wherein a light emitting layer is selectively formed in a concave area formed by using a photoresist instead of photolithography. Things.
[0002]
[Prior art]
The organic EL element can be driven at a relatively low voltage, is self-luminous, and has a fast response, so that it has excellent image visibility, is suitable for displaying moving images, and is used only as a stationary display. Rather, the use thereof is also spreading as a portable display such as a portable display.
[0003]
In a general organic EL device, a hole buffer layer and an organic phosphor layer are sequentially formed on a glass substrate on which a transparent electrode (first electrode) such as ITO is formed, and a metal electrode (second electrode) is formed. It is formed and further covered with a protective layer.In order to make a pattern-like display, in addition to patterning both electrodes, an organic phosphor layer is patterned or a hole buffer layer and an organic The light emitting layer is patterned, for example, by patterning both of the phosphor layers.
[0004]
As a method of patterning the buffer layer and the organic phosphor layer, those layers are formed on one surface of a substrate, a photoresist layer is formed, exposure and development are performed to form a resist pattern, and the resist pattern is formed. There is a photolithography method in which etching is performed by utilizing the above. (For example, refer to Patent Document 1).
In addition, there is also an ink-jet method in which a partition for separating pixels is provided over a substrate, and a hole injection layer and a light-emitting layer are both applied between the partitions by an ink-jet method. (For example, see Patent Document 2).
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-170673 (Claim 7, Example 1)
[Patent Document 2]
Japanese Patent Application Laid-Open No. 2000-323276 (Claims 1 and 2, FIG. 4)
[0006]
However, according to the above-described photolithography method, although a pattern having excellent pattern accuracy such as an organic phosphor layer of an obtained organic EL device can be obtained, application of a photoresist solution to the organic phosphor layer and the like, , Exposure and development steps, it is necessary to carry out the application of the photoresist solution, and there is concern about the chemical effects of the solvent and monomers in the solution on the organic phosphor layer, etc. There are concerns about the effects of the exposure, the effects of exposure light during exposure, and the effects of development conditions. For example, when the development is performed with an alkali developing solution, there is a concern about the influence of alkali. Further, when etching is performed with an etching solution using the resist thus formed, the etching solution can permeate the light emitting layer from around the portion covered with the resist. There is a concern that the function of the organic phosphor may be deteriorated.
[0007]
In addition, according to the above-described inkjet method, the disadvantages of the photolithography method can be eliminated, the light-emitting layer can be formed in a short time, and the manufacturing efficiency is improved. It is necessary to form a liquid-repellent partition wall in order to separate them or to prevent color mixing. However, due to poor adaptation of the coating liquid to the liquid-repellent partition walls, the thickness of the coating film of the coating liquid applied by the inkjet method is thin near the partition walls, and becomes thicker away from the partition walls. There is a disadvantage that the thickness is not uniform and light emission unevenness is apt to occur. Further, in the inkjet method, the ejection direction of the ink drop is not stable, and the ink may fly to pixels other than the target pixel, causing color mixing.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide a new method of manufacturing an organic EL device while maintaining the point that the pattern accuracy in the conventional photolithography method is excellent, and making use of the high manufacturing efficiency of the ink jet method. As an issue.
[0009]
[Means to solve the problem]
According to the study by the inventors, a method of first applying a mask on a substrate using a photoresist, forming a light emitting layer by an ink jet method on a portion where the mask is not applied, and removing the mask later is adopted. The position where the light emitting layer is formed is accurately determined by the photoresist, and the formation of the light emitting layer can be efficiently performed by simply applying a coating liquid to an unmasked portion by an ink jet method or the like. By repeating these steps, it was found that multicolor light-emitting layers could be produced without mixing with each other, and the present invention was achieved.
[0010]
According to a first aspect, a light-emitting layer including a layer containing an organic phosphor capable of emitting light by recombination of electrons injected from one electrode and holes injected from the other electrode is provided between a pair of electrodes. In manufacturing an organic EL device having at least a laminated structure, a layer of an ionizing radiation-sensitive resin composition whose solubility can be changed by irradiation with ionizing radiation is laminated on any one of the above-mentioned electrodes. A layer of the ionizing radiation-sensitive resin composition, irradiating the layer of the ionizing radiation-sensitive resin composition with a pattern of ionizing radiation, and developing after the irradiation to remove the layer of the ionizing radiation-sensitive resin composition at a desired position. An organic EL device, wherein a concave portion forming step of forming a concave portion having the upper surface of the electrode as a bottom surface and a light emitting layer laminating step of laminating the light emitting layer in the concave portion are sequentially performed. A method of manufacturing a child.
[0011]
According to a second aspect, in the first aspect, the ionizing radiation-sensitive resin composition laminating step, the concave part forming step, and the light emitting layer laminating step are performed when the position of the concave part in the concave part forming step is different each time. The present invention also relates to a method for manufacturing an organic EL device, which is performed twice or more.
[0012]
According to a third aspect, in the second aspect, the step of laminating the ionizing radiation-sensitive resin composition, the step of forming the concave portion, and the step of laminating the light-emitting layer are performed such that the emission colors of the organic phosphor are red, blue, and green. The present invention relates to a method for manufacturing an organic EL element, wherein the method is performed three times, each time using an organic phosphor having a different emission color, each time.
[0013]
A fourth invention relates to the method for manufacturing an organic EL device according to any one of the first to third inventions, wherein the light emitting layer laminating step comprises a buffer layer laminating step and an organic phosphor layer laminating step. Things.
[0014]
In a fifth aspect based on any one of the first to third aspects, the light-emitting layer comprises a layer containing the organic phosphor, and a hole transport layer and / or an electron transport layer. The present invention relates to a method for manufacturing an EL element.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 to FIG. 3 are diagrams showing each step of the method for manufacturing an organic EL device of the present invention.
[0016]
As shown in FIG. 1A, a substrate 1 on which a first electrode layer 2 is laminated on an upper surface is prepared, and a photoresist layer 3A is laminated on the entire surface of the first electrode layer 2 on the substrate 1. The photoresist layer 3A is made of an ionizing radiation-sensitive resin composition (usually an ultraviolet-sensitive resin composition) whose solubility can be changed by ionizing radiation irradiation, usually ultraviolet irradiation, and the composition is applied by coating or the like. Formed by
[0017]
Irradiating ionizing radiation such as ultraviolet rays in a pattern from the photoresist layer 3A side to the laminate in which the substrate 2, the first electrode layer 3A, and the photoresist layer 3A are sequentially laminated, and performing development after the irradiation. As a result, a desired portion of the photoresist layer 3A is removed. In the portion where the photoresist layer 3A has been removed, a recess 4A having the upper surface of the first electrode layer 2 on the substrate 1 as a bottom surface is formed (FIG. 1B).
[0018]
In the case where the ionizing radiation-sensitive resin composition constituting the photoresist layer 3A is of a type (negative type) whose solubility is reduced due to polymerization or crosslinking by irradiation with ionizing radiation, a portion other than the portion where the concave portion 4A is to be formed. Irradiation with ionizing radiation is performed through a pattern in which ionizing radiation is irradiated to the portion of the surface, or the ionizing radiation is scanned and irradiated so as to be selectively applied to a portion other than the portion where the concave portion 4A is to be formed. Do.
[0019]
When the ionizing radiation-sensitive resin composition constituting the photoresist layer 3A is of a type (positive type) whose solubility is improved by being decomposed by irradiation with ionizing radiation or the like, the ionizing radiation is applied to a portion where the concave portion 4A is to be formed. Irradiation is performed through a pattern that irradiates the ionizing radiation, or scanning is performed so that the ionizing radiation is selectively applied to a portion where the concave portion 4A is to be formed. FIGS. 1 to 3 are drawn on the assumption that the latter positive type is used.
[0020]
Development after irradiation with ionizing radiation, using a solvent capable of selectively dissolving the part other than the place where the solubility has been reduced by the above-described ionizing radiation, or a solvent capable of selectively dissolving the part whose solubility has been improved, the photoresist layer Performed by causing selective dissolution of 3A.
[0021]
A light emitting layer is laminated on a concave portion 4A formed in a laminated body in which the substrate 1, the first electrode layer 2, and the photoresist layer 3A are sequentially laminated. As shown in FIG. 1C, for example, the light emitting layer is formed by sequentially stacking a buffer layer 5A and an organic phosphor layer 6A from the first electrode layer 2 side (FIG. 1C).
[0022]
In this manner, the light emitting layer is stacked on the first electrode layer 2 on the substrate 1 in the concave portions not masked by the photoresist layer 3A. Therefore, the position where the light emitting layer is formed and the planar shape of the light emitting layer are Is determined by the steps of laminating the photoresist layer, exposing in a pattern, and developing. Since these steps are the same as the steps of forming the etching resist in the photolithography method, the light emitting layer is formed by the photolithography method. As in the case of the above, an organic EL element having excellent pattern accuracy can be formed. If necessary, the remaining photoresist layer 3A is removed, and a second electrode layer is further formed on the formed light emitting layer so as to face the first electrode layer, and the first electrode layer and the second electrode layer are formed. By applying a potential between the electrode layers, the light emitting layer can emit light.
[0023]
Therefore, it is possible to emit light in an appropriate pattern by setting the shape of the recess 4A to an appropriate pattern. The planar shape of the concave portion 4A is a fine area such as a circle, a square, or a stripe, and a large number of such fine areas are densely arranged, so that a light emitting layer in which a large number of such fine areas are densely arranged. Is formed, an arbitrary character or numeral, an image, or the like can be displayed by selecting an arbitrary minute area among them and applying an electric potential.
[0024]
In the above description, even if a large number of concave portions 4A are formed, they merely form the same type of light emitting layer, and all of the multiple light emitting layers give the same light emitting color. By applying the method described above, as described below, the materials involved in light emission in the light-emitting layer are changed, and thus, a plurality of types of light-emitting layers having different emission colors are formed side by side, and each of them emits light. It is also possible to obtain a plurality of luminescent colors at the same time.
[0025]
FIG. 2 is a view showing a process of further forming another light emitting layer on the one obtained by the above description referring to FIG. 1 (FIG. 1C). First, as shown in FIG. 1 (c), a first electrode layer 2 is laminated on a substrate 1 and is covered (masked) with a photoresist layer 3A, and is not masked by the photoresist layer 3A. As a light emitting layer, a photoresist layer 3B is laminated on the entire surface of the laminate in which the buffer layer 5A and the organic phosphor layer 6A are laminated from the first electrode layer 2 side (FIG. 2A).
[0026]
The photoresist layer 3B may be composed of the same ionizing radiation-sensitive resin composition as that constituting the photoresist layer 3A, or may be composed of different ionizing radiation-sensitive resin compositions.
[0027]
The laminated photoresist layer 3B is irradiated with ionizing radiation such as ultraviolet rays in a pattern from the photoresist layer 3B side, and after the irradiation, development is performed. Then, at a position different from the position where the concave portion 4A is formed using the photoresist layer 3A, the pattern is changed or scanning is performed so that the solubility of the photoresist layer 3B and the lower photoresist layer 3A is relatively increased. The condition is changed to form a concave portion 4B at a position different from the concave portion 4A (FIG. 2B).
[0028]
The light emitting layer is laminated on the formed concave portion 4B. As shown in FIG. 2C, for example, the light emitting layer is formed by sequentially stacking a buffer layer 5B and an organic phosphor layer 6B from the first electrode layer 2 side. The buffer layer 5B is preferably made of the same material as the buffer layer 5A previously formed in the recess 4A, but may be different from each other. The organic phosphor layer 6B is preferably made of a different material for the purpose of obtaining a plurality of luminescent colors with one organic EL element, but may be made of the same material.
[0029]
In the above description with reference to FIG. 2, since the light emitting layers with the electron injection layers are separately formed in the recesses 4A and 4B, the remaining photoresist layers 3A and 3B are removed as necessary. On these light emitting layers, a second electrode layer is formed so as to face the first electrode layer, and by applying a potential between the first electrode layer and the second electrode layer, these light emitting layers emit light. be able to. At this time, by using materials having different emission colors from each other as materials constituting each light-emitting layer, in particular, organic phosphors for forming the organic phosphor layers 6A and 6B, each light-emitting layer has a different color. For example, it is possible to alternately emit light of these two colors by setting each light emission color to red and blue, or to simultaneously emit light of these two colors to mix colors.
[0030]
By the way, in order for an organic EL element to perform full-color display, three primary colors of light, red, green and blue, are required. As described above, in order to emit light of three colors, the light emission colors of the two kinds of light-emitting layers already obtained are different from those obtained in the above description with reference to FIG. If it is blue, it is necessary to further form a third kind of light emitting layer containing an organic phosphor of a different color, for example, a green light emitting color.
[0031]
In order to form the third kind of light emitting layer, the laminate (FIG. 2C) in which the two kinds of light emitting layers are formed as described above is formed on the entire surface on the side where the photoresist layers 3A and 3B are stacked. Then, a photoresist 3C is laminated (FIG. 3A). The photoresist layer 3C may be composed of the same ionizing radiation-sensitive resin composition as that constituting the photoresist layer 3A or 3B, or may be composed of an ionizing radiation-sensitive resin composition different from 3A or 3B. Is also good.
[0032]
Next, from the side of the photoresist layer 3C, at a position different from the concave portions 4A and 4B, the irradiation portions of the photoresist layers 3C, 3B, and 3A have a pattern-like ionizing radiation so that the solubility is relatively increased. Irradiation is performed to form a concave portion 4C at a position different from the above concave portions 4A and 4B (FIG. 3B).
[0033]
As shown in FIG. 3C, for example, a buffer layer 5C and an organic phosphor layer 6C are sequentially laminated on the formed concave portion 4C from the first electrode layer 2 side. The buffer layer 5C may be made of the same material as the previously formed buffer layer 5A or 5B, or may be made of a different material. The organic phosphor layer 6C is preferably made of a material different from the above-described organic phosphor layers 6A and 6B for the purpose of obtaining three emission colors with one organic EL element. The organic phosphor layers 6A and 6B can be made of the same material.
[0034]
If necessary, the remaining photoresist layers 3A, 3B and 3C are also removed from the laminate in which the three types of light emitting layers are formed as described above, and further, a second electrode is formed on these light emitting layers. By forming a layer facing the first electrode layer and applying a potential between the first electrode layer and the second electrode layer, these three types of light emitting layers can emit light, and characters, numerals, Alternatively, a so-called full-color display in which an image or the like is displayed in a desired color becomes possible.
[0035]
Accordingly, by performing the ionizing radiation-sensitive resin composition laminating step, the concave part forming step, and the light emitting layer laminating step twice by changing the position of the concave part in the concave part forming step each time, two-color light emission is performed. It is possible to obtain an organic EL element capable of performing full-color display by performing each of these steps three times and setting each emission color to each of the three primary colors of light. Can be.
[0036]
Note that it is preferable to repeat the same steps as described above in terms of preparing necessary materials and equipment, but another light emitting layer forming step may be used in combination if necessary. As another light emitting layer forming step, a method using a vapor phase forming method such as vapor deposition, a method using ink jet or printing, or a light emitting layer formed on one surface, a resist pattern using a photoresist is used. A photolithography method of forming a resist pattern and etching with an etchant using the resist pattern can also be used.
[0037]
In a general organic EL element, if there are two or more types of light emitting layers, fine areas constituting each light emitting layer, that is, fine areas a1, a2, a3,... The fine areas b1, b2, b3,... Constituting the light emitting layer B are, for example, mosaic, stripe, or triangular as a1, b1, a2, b2, a3, b3,. It is usual to be an array of Therefore, when a partition is simply provided around a fine area and a light-emitting layer is provided by an ink-jet method, ink adheres to an adjacent fine area and color mixing may occur. However, when at least one of the two or more light emitting layers is formed by the method for manufacturing an organic EL device of the present invention, the adjacent area is covered with a photoresist layer, and color mixing may occur. Absent. Accordingly, there is an advantage that even if there is instability in the ink ejection direction in the ink jet method, color mixing caused by ink adhering to adjacent fine areas can be completely avoided.
[0038]
In the method for manufacturing an organic EL device of the present invention, materials used for forming each layer, processing conditions in each step, materials used for processing, and the like are as follows.
[0039]
The organic EL element basically has a laminated structure in which at least a light-emitting layer composed of a layer containing an organic phosphor is laminated between a pair of electrodes. Is often supported by On the other electrode, a protective layer may be stacked or another substrate may be stacked. The substrate 1 is made of a plate-like or film-like material. Specific examples of the material include an inorganic material such as glass (including a sheet-like thin-film glass) or quartz, or a resin plate or a resin film. Can be mentioned. Note that the term “substrate” is used in a sense that it includes a film-like material, and may be called a base material. If the substrate is a rollable or bendable substrate such as a resin film or a sheet-like thin film glass (these are collectively referred to as a flexible substrate), the substrate can be rolled or bent. A flexible organic EL element can also be obtained.
[0040]
The resin of the resin plate or the resin film that can constitute the substrate 1 is not particularly limited, but preferably has relatively high solvent resistance and heat resistance. Further, although it depends on the application, it is preferable that the material has a gas barrier property of blocking gas such as water vapor or oxygen. Specific resins include fluorine resin, polyethylene, polypropylene, polyvinyl chloride, polyvinyl fluoride, polystyrene, ABS resin, polyamide, polyacetal, polyester, polycarbonate, modified polyphenylene ether, polysulfone, polyarylate, polyetherimide, polyamide Imide, polyimide, polyphenylene sulfide, liquid crystalline polyester, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyoxymethylene, polythioether, polyether sulfone, polyether ether ketone, polyacrylate, polyalkyl methacrylate, acrylonitrile-styrene resin, Phenolic resin, urea resin, melamine resin, unsaturated polyester resin, epoxy resin, Examples thereof include urethane, silicone resin, and amorphous polyolefin. Other than these, any polymer material that satisfies the conditions can be used. It may be a copolymer obtained by polymerization.
[0041]
In order for a display obtained by operating the organic EL element to be visible to an observer, it is preferable that the substrate on the observation side has transparency. When the substrates 1 are arranged on both sides of the organic EL element, Preferably, one or both have transparency.
[0042]
When a resin plate or a resin film is used as the substrate 1, a barrier layer may be laminated in order to provide a gas barrier property of blocking a gas such as water vapor or oxygen. It is preferable to stack a thin film of silicon, aluminum oxide, silicon nitride, or the like.
[0043]
The substrate 1 is usually provided with an electrode (referred to as a first electrode in the order of formation, usually an anode). The first electrode layer 2 in the above description corresponds to this. Typically, the anode is made of indium tin oxide (ITO), indium oxide, gold, polyaniline, or the like. Note that a cathode (a second electrode, which corresponds to the second electrode layer in the above description) serving as a counter electrode is laminated on the light emitting layer after forming the light emitting layer, and the cathode is a magnesium alloy (MgAg or the like). , Aluminum alloys (AlLi, AlCa, AlMg, etc.) or metallic calcium as a material. The anode and / or the cathode are formed by forming a layer on one surface by a vapor phase method such as evaporation or sputtering using these materials, or by forming a layer formed on one surface using a photosensitive resist. By etching, an electrode pattern having a predetermined shape can be laminated.
[0044]
The photoresist layer 3A, 3B, or 3C is composed of an ionizing radiation-sensitive resin composition, and the ionizing radiation referred to here is specifically an ultraviolet ray or an electron beam. It is preferable to use an ultraviolet-sensitive resist (commonly referred to as a photoresist), which is convenient in terms of the ease of irradiation and more specifically, is used as an etching resist.
[0045]
As the photoresist, a positive type photoresist, for example, a photo-soluble type quinonediazide-based photosensitive resin or the like as a main component, or a negative type photoresist, for example, a photo-degradable cross-linked azide -Based photosensitive resin, photo-decomposable insoluble diazo-based photosensitive resin, photo-dimerized cinnamate-based photosensitive resin, photo-polymerized unsaturated polyester-based photosensitive resin, photo-polymerized acrylate resin, or cationic polymer-based resin And the like as a component. In addition to these photosensitive resins, a photosensitive resin composition in which a photopolymerization initiator, a sensitizing dye, and the like are blended as necessary can be used as a photoresist.
[0046]
As the organic phosphor that directly emits light from the light emitting layer, for example, a dye-based, metal complex-based, or polymer-based one can be used.
[0047]
Dye-based compounds include cyclopendamine derivatives, tetraphenylbutadiene derivatives, triphenylamine derivatives, oxadiazol derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, silole derivatives, thiophene ring compounds, pyridine Examples include a ring compound, a perinone derivative, a perylene derivative, an oligothiophene derivative, an oxadiazole dimer, and a pyrazoline dimer.
[0048]
Examples of the metal complex type include aluminum quinolinol complex, benzoquinolinol beryllium complex, benzoxazole zinc complex, benzothiazole zinc complex, azomethyl zinc complex, porphyrin zinc complex, europium complex, and the like, and Al, Zn, Be, etc. , Tb, Eu, Dy and the like, and a metal complex having a ligand such as an oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, or quinoline structure.
[0049]
As the high molecular type, a polyparaphenylene vinylene derivative, a polythiophene derivative, a polyparaphenylene derivative, a polysilane derivative, a polyacetylene derivative, etc., a polyfluorene derivative, or a polyvinyl carbazole derivative, or the above-described dye-based or metal complex-based And those obtained by polymerizing the above.
[0050]
The above-mentioned organic phosphor can be doped for the purpose of improving the light emission efficiency or changing the light emission wavelength. Examples of the doping material include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squarium derivatives, porphyrene derivatives, styryl dyes, tetracene derivatives, pyrazoline derivatives, decacyclene, and phenoxazone.
[0051]
The organic phosphor is prepared by dissolving a solution obtained by dissolving the organic phosphor in a solvent on the first electrode layer 2 or on the buffer layer, or on other layers provided as necessary by an appropriate coating method or printing method. The organic phosphor layer can be applied to the organic phosphor layer, and the production efficiency is excellent when using these coating methods or printing methods. In the method for manufacturing an organic EL device of the present invention, since the light emitting layer is applied to the concave portion formed by being masked by the photoresist layer, among the methods in the category of the coating method or the printing method, in particular, by the ink jet method or the dispenser method. In particular, according to the ink-jet method, the formation of the light-emitting layer can be performed in the shortest time, and the ink can be adhered only to a target portion. The efficiency is high, and the production efficiency is the best. Among the above-mentioned organic phosphors, polymer-based ones are suitable for forming an organic phosphor layer by a coating method or a printing method, since a suitable viscosity can be obtained when a solution is used.
[0052]
The light-emitting layer may be composed of the organic phosphor layer alone, but may be accompanied by a buffer layer. As described above, the light-emitting layer may be composed of the buffer layer and the organic phosphor layer. .
[0053]
The buffer layer referred to in the present invention is an organic substance, particularly an organic conductive layer, provided between an anode and a light-emitting layer or between a cathode and a light-emitting layer so that charge injection into an organic phosphor layer is easily performed. For example, a conductive polymer having a function of increasing hole injection efficiency into a light emitting layer and flattening unevenness of an electrode or the like can be used.
[0054]
Specific examples of the material for forming the buffer layer used in the present invention include polyalkylthiophene derivatives, polyaniline derivatives, polymers of hole-transporting substances such as triphenylamine, sol-gel films of inorganic oxides, trifluoromethane and the like. And a film of an organic compound containing a Lewis acid, which is commercially available as a composition for forming a hole injection buffer layer, such as poly (3,4) ethylenedioxythiophene / polystyrenesulfonate ( PEDOT / PSS (manufactured by Bayer AG, trade name; Baytron P AI 4083, commercially available as an aqueous solution)) and the like can also be used. These materials can be dissolved or dispersed in a solvent to form a coating, and the buffer layer can be formed by an appropriate coating method or printing method. In addition, a buffer layer can also be formed by a vapor phase method such as evaporation or sputtering using a generally used buffer material, hole injection material, or hole transport material.
[0055]
In the present invention, the organic phosphor layer in the light-emitting layer is preferably a shape in which a large number of fine areas such as a circle, a square, or a stripe are densely arranged. When the property is high, it is preferable that the patterning is performed in order to maintain the diode characteristics of the element and prevent crosstalk.
[0056]
As the light emitting layer, an example in which a buffer layer and an organic phosphor layer are stacked from the substrate 1 side has been described as an example. However, the light emitting layer may have a stacked structure including various layers.
[0057]
For example, the light emitting layer may have a laminated structure in which a hole transport layer made of a hole transport material is provided on the anode side and / or an electron transport layer made of an electron transport material is provided on the cathode side.
[0058]
When the organic phosphor layer also has the property of a hole transport layer, the light emitting layer may have a laminated structure in which an electron transport layer is laminated on the cathode side of the organic phosphor layer and hole transport layer. Alternatively, when the organic phosphor layer also has the property of an electron transport layer, the light emitting layer may have a laminated structure in which a hole transport layer is laminated on the anode side of the electron transport layer and the organic phosphor layer.
[0059]
Further, the light emitting layer may have a laminated structure of a hole transporting material / organic phosphor mixed layer and an electron transporting layer formed by mixing at least both a hole transporting material and an organic phosphor, or , A hole transport layer and a mixed layer of an organic phosphor / electron transport material formed by mixing at least both an organic phosphor and an electron transport material. Further, the light emitting layer may be composed of a mixed layer in which at least three of a hole transport material, an organic phosphor, and an electron transport material are mixed.
[0060]
When the light emitting layer has a laminated structure of various layers, in addition to the material constituting the buffer layer and the material constituting the organic phosphor layer, using the materials listed in the following paragraphs, the buffer layer or the organic Similarly to the phosphor layers, it can be formed preferably by a coating method or a printing method using a solution in which the materials constituting the layers are dissolved, preferably by an ink jet method or a dispenser method.
[0061]
Electron transport materials include anthraquinodimethane, fluorenylidenemethane, tetracyanoethylene, fluorenone, diphenoquinone oxadiazole, anthrone, thiopyran dioxide, diphenoquinone, benzoquinone, malononitrile, nitrotrobenzene, nitroanthraquinone, anhydrous Maleic acid, perylenetetracarboxylic acid, or a derivative thereof can be used.
[0062]
As the hole transporting material, in addition to those described above as the material constituting the buffer layer, porphyrin, triazole, imidazole, imidazolone, pyrazoline, tetrahydroimidazole, hydrazone, stilbene, or butadiene, or a derivative thereof may be used. it can.
[0063]
An electrode (second electrode layer, usually a cathode) for the electrode (first electrode layer) on the substrate 1 side is provided on the light emitting layer. The material constituting the cathode and the forming method are as described above.
[0064]
On the second electrode layer, a sealing layer (also referred to as a protective layer) is usually applied. The sealing layer can be formed by either an inorganic thin film or an organic (resin) coating film, and covers the upper surface provided with the second electrode layer. In addition to forming these sealing layers, the outermost surface may be covered with an inorganic material such as glass or quartz mentioned as a material of the substrate 1 or a resin plate or a resin film.
[0065]
【The invention's effect】
According to the first aspect of the present invention, since the concave portion is formed by the ionizing radiation-sensitive resin composition and the light emitting layer is formed in the concave portion, it is the same as the conventional case where the light emitting layer is formed by the photolithography method. An organic EL device capable of achieving excellent pattern accuracy of the obtained organic EL element and capable of forming a light emitting layer efficiently and in a short time by a method in the category of a coating method or a printing method. A method for manufacturing an element can be provided.
[0066]
According to the invention of claim 2, in addition to the effect of the invention of claim 1, a series of steps of forming a concave portion with the ionizing radiation-sensitive resin composition and forming a light emitting layer in the concave portion include forming a concave portion. By repeating the operation two or more times at different places, it is possible to provide a method for manufacturing an organic EL element capable of forming two or more types of light emitting layers.
[0067]
According to the invention of claim 3, in addition to the effect of the invention of claim 2, the organic phosphor is formed each time so that the emission color of the organic phosphor for forming each light emitting layer becomes each of the three primary colors of light. Alternatively, it is possible to provide a method of manufacturing an organic EL element capable of performing full-color display by performing a series of steps three times.
[0068]
According to a fourth aspect of the present invention, in addition to the effects of the first to third aspects of the present invention, there is provided a method of manufacturing an organic EL device in which a light emitting layer can be constituted by a buffer layer and an organic phosphor layer. can do.
[0069]
According to the invention of claim 5, in addition to the effect of any one of claims 1 to 3, the light emitting layer is formed of a layer containing the organic phosphor, and a hole transport layer and / or an electron transport layer. It is possible to provide a method for manufacturing an organic EL element that can be configured.
[Brief description of the drawings]
FIG. 1 is a view showing each step of a method for manufacturing an organic EL device of the present invention.
FIG. 2 is a view showing each step of a manufacturing method for forming two kinds of light emitting layers.
FIG. 3 is a view showing each step of a manufacturing method for forming three kinds of light emitting layers.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 substrate 2 first electrode layer 3 photoresist layer 4 recess 5 buffer layer 6 organic phosphor layer

Claims (5)

A stacked structure in which at least a light-emitting layer including a layer containing an organic phosphor capable of emitting light by recombination of electrons injected from one electrode and holes injected from the other electrode is stacked between a pair of electrodes. For producing an organic EL device having a structure, a step of laminating a layer of an ionizing radiation-sensitive resin composition whose solubility can be changed by irradiation with ionizing radiation on any one of the above-mentioned electrodes; By irradiating the layer of the ionizing radiation-sensitive resin composition with ionizing radiation in a pattern and developing after the irradiation, the layer of the ionizing radiation-sensitive resin composition at a desired position is removed to remove the upper surface of the electrode. A concave portion forming step of forming a concave portion having a bottom as a bottom surface, and a light emitting layer laminating step of laminating the light emitting layer in the concave portion. The ionizing radiation-sensitive resin composition laminating step, the concave part forming step, and the light emitting layer laminating step are performed two or more times by changing the position of the concave part in the concave part forming step each time. A method for manufacturing an organic EL device according to claim 1. The ionizing radiation-sensitive resin composition laminating step, the concave part forming step, and the light emitting layer laminating step are performed such that the organic phosphor emits red, blue, and green, respectively, so that the organic fluorescent light is emitted each time. 3. The method for producing an organic EL device according to claim 2, wherein the step is carried out three times using a body having a different emission color. The method according to any one of claims 1 to 3, wherein the light emitting layer laminating step includes a buffer layer laminating step and an organic phosphor layer laminating step. The method according to any one of claims 1 to 3, wherein the light emitting layer comprises a layer containing the organic phosphor, and a hole transport layer and / or an electron transport layer.

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