JP2005032735A - Electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an electroluminescent element, whereby high luminous efficiency, high extraction efficiency, a simplified manufacturing process, and formation of high definition pattern are materialized. <P>SOLUTION: Patterning is applied to at least one layer of an organic electroluminescent layer by using a photo-lithography method in this manufacturing method of the electroluminescent element. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a patterned electroluminescent (hereinafter sometimes abbreviated as EL) element.

  In the EL element, holes and electrons injected from opposing electrodes are combined in the light emitting layer, and the fluorescent material in the light emitting layer is excited with the energy to emit light of a color corresponding to the fluorescent material. It attracts attention as a self-luminous planar display element. Among them, organic thin-film EL displays using organic substances as light-emitting materials have high light-emission efficiency such as high-luminance light emission even when the applied voltage is less than 10 V, and can emit light with a simple element structure. It is expected to be applied to advertisements that display these patterns in light emission and other simple display displays at low cost.

  In manufacturing a display using such an EL element, patterning of an electrode layer or an organic EL layer is usually performed. As a patterning method of this EL element, there are a method of evaporating a luminescent material through a shadow mask, a method of coating by ink jet, a method of destroying a specific luminescent dye by ultraviolet irradiation, a screen printing method and the like. However, these methods cannot provide an EL element that realizes all of light emission efficiency, high light extraction efficiency, simple manufacturing process, and high-definition pattern formation.

  The present invention has been made in view of the above circumstances, and has as its main object to provide an EL element that realizes high luminous efficiency, high extraction efficiency, simple manufacturing process and high-definition pattern formation. It is.

  In order to achieve the above object, according to the present invention, an EL device having at least one patterned organic EL layer as defined in claim 1, comprising a partition wall, a composition for assisting patterning, and patterning. Provided is an EL element which does not have any auxiliary surface treatment.

  Since the EL element of the present invention does not have a partition wall or the like as described above, it has an advantage of low cost.

  According to a second aspect of the present invention, there is provided an EL device having at least one organic EL layer, wherein the organic EL layer is a patterned light emitting layer, and an end of the patterned light emitting layer. The EL element is characterized in that the width of the non-uniform thickness region formed in the portion is 15 μm or less.

  In the EL element of the present invention, since the width of the non-uniform film thickness region is 15 μm or less, the interval between patterns can be reduced, and a high-definition pattern can be obtained. Here, the “film thickness non-uniform region” indicates a region where the film thickness is reduced from the film thickness of the flat portion, and the region having a film thickness of 90% or less of the average film thickness of the flat portion. It is shown.

  Furthermore, in the present invention, as shown in claim 3, the EL element having at least one organic EL layer, wherein the organic EL layer is a plurality of patterned light emitting layers capable of emitting a plurality of colors. The EL element is characterized in that the distance between adjacent light emitting layers emitting different colors is 30 μm or less. Thus, since the distance between the pixels can be reduced, a higher quality image display can be performed.

  In the invention described in any one of claims 1 to 3, as described in claim 4, at least a substrate, and an electrode layer formed in a pattern on the substrate, It is preferable to have an insulating layer formed so as to cover the edge portion of the electrode layer and the non-light emitting portion of the element. This is because a short circuit in a portion unnecessary for light emission can be prevented, defects due to a short circuit of the element, etc. can be reduced, and an element capable of obtaining long-life and stable light emission can be obtained.

  In the invention described in any one of claims 1 to 4, as described in claim 5, the organic electroluminescent layer includes at least a buffer layer. Is preferred.

  According to the present invention, since it is obtained by patterning at least one organic EL layer in an EL element by a photolithography method, it has an alignment mechanism as compared with a conventional patterning method by vapor deposition. Since no vacuum equipment or the like is required, it can be manufactured relatively easily and inexpensively. On the other hand, compared with the patterning method by ink jet, it is preferable in that it does not perform pre-treatment on the structure and substrate for assisting patterning, and the manufacturing method of the present invention is more preferable in relation to the ejection accuracy of the ink jet head. It can be said that this is a preferable method for forming a high-definition pattern. Therefore, according to the EL element manufacturing method of the present invention, a high-definition EL element can be obtained relatively easily and inexpensively.

  In addition, according to the present invention, impurities are not mixed in the light emitting layer, the light emission efficiency and the light extraction efficiency are high, the manufacturing process is simplified, the mass production is high, the pattern formation capable of uniform light emission is high, and the crosstalk is reduced. It is possible to provide an EL element manufacturing method and an EL element that realize all of the above.

  More specifically, for example, by patterning the buffer layer, it is possible to reduce crosstalk in driving a simple matrix element. In addition, by patterning the buffer layer and the light emitting layer produced by coating, it is possible to simultaneously remove, for example, insoluble portions that are normally performed by laser removal or wiping, and the process can be simplified. . Further, the process can be simplified in that it is not necessary to use any of barrier ribs, a composition having ink repellency for assisting patterning, and a surface treatment having ink repellency for assisting patterning. In addition, the present invention is excellent in that the emission color can be controlled and patterned in any EL element that emits light in an arbitrary pattern or EL element that emits full color light, and even in an EL element that uses a flexible substrate. .

  Hereinafter, the EL element manufacturing method of the present invention will be described first, and then the EL element of the present invention having a new feature that has not been conventionally used, which can be manufactured by this EL element manufacturing method, will be described.

A. EL Element Manufacturing Method The EL element manufacturing method of the present invention is characterized in that at least one organic EL layer constituting the EL element is patterned using a photolithography method.

  In the EL element manufacturing method of the present invention, at least one organic EL layer constituting the EL element is formed by a photolithography method as described above. Therefore, a vapor deposition method performed through a conventional shadow mask and In comparison, since a vacuum device or the like is unnecessary, the organic EL layer can be patterned easily and inexpensively. On the other hand, as compared with patterning by the ink jet method, high-definition patterning can be performed without the necessity of pretreatment of the substrate or provision of liquid-repellent convex portions between the patterns. That is, according to the EL element manufacturing method of the present invention, a high-quality EL element having a high-definition pattern can be obtained at a low cost.

  Hereafter, each structure in the manufacturing method of such an EL element of this invention is demonstrated concretely.

(Organic EL layer)
The EL element in the present invention has at least one patterned organic EL layer, specifically, a first electrode layer, an EL layer formed on the first electrode layer, and the above The EL layer includes at least a second electrode layer formed on the EL layer, and the EL layer includes at least one organic EL layer to be patterned.

  Here, the EL layer needs to include at least a light emitting layer, and in addition, a buffer layer, a hole transport layer, a hole injection layer, an electron transport layer, an electron injection layer, and the like may be combined. .

  In addition, the organic EL layer to be patterned may be any layer that constitutes the EL layer described above, but in the present invention, it is preferably a light emitting layer or a buffer layer. It is preferable that the layer is patterned in that the effect of the present invention can be exhibited to the maximum. Furthermore, it can be said that it is the most preferable example that the light emitting layer and the buffer layer are patterned as an organic EL element in terms of light emission characteristics.

  Specifically, a buffer layer as an organic EL layer is formed by patterning on the first electrode layer by a photolithography method, and a light emitting layer is further formed on the first electrode layer by patterning by a photolithography method. An EL layer on which a second electrode layer is formed is a preferred example, and in particular, the above-mentioned light emitting layer is three kinds of light emitting layers, and is a full color EL element formed by patterning three times by photolithography. It is the most preferred example.

  The present invention is characterized in that patterning of such an organic EL layer is performed using a photolithography method, and the other layers can be manufactured by a conventionally used method. .

(Photolithography method)
The EL device manufacturing method of the present invention is characterized in that the organic EL layer is patterned by a photolithography method. This photolithography method is a method of forming an arbitrary pattern according to the light irradiation pattern by utilizing the fact that the solubility of the light irradiation portion of the film is changed by light irradiation. Hereinafter, this photography method will be described.

(Photoresist)
The photoresist that can be used in the present invention is not particularly limited, whether it is a positive type or a negative type, but is preferably insoluble in a solvent used for forming an organic EL layer such as a light emitting layer. .

  Specific examples of the photoresist that can be used include novolak resin-based, rubber + bisazide-based, and the like.

(Photoresist solvent)
In the present invention, as the photoresist solvent used when coating the photoresist, the above-described organic EL layer such as a light emitting layer and the photoresist material are prevented from being mixed or dissolved during the photoresist film formation. In order to maintain the light emission characteristics, it is desirable to use a material that does not dissolve the organic EL material such as the light emitting layer material. Considering this point, the photoresist solvent that can be used in the present invention has a solubility in an organic EL layer forming material such as a light emitting layer forming material of 0.001 (g / g at 25 ° C. and 1 atm). Solvent) The following solvent is preferably selected, and more preferably 0.0001 (g / g solvent) or less is selected.

  For example, as a photoresist solvent that can be used when the buffer layer forming material is dissolved in an aqueous solvent and the light emitting layer is dissolved in an aromatic non-polar organic solvent, ketones such as acetone and methyl ethyl ketone are used. Cellosolve acetates such as propylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monoethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether Cellosolves such as ethylene glycol monoethyl ether, methanol, ethanol, 1-butanol, 2-butanol , Alcohols such as cyclohexanol, ester solvents such as ethyl acetate and butyl acetate, cyclohexane, decalin and the like can be used. It may be a solvent.

(Photoresist developer)
The photoresist developer that can be used in the present invention is not particularly limited as long as it does not dissolve the material for forming the organic EL layer. Specifically, a commonly used organic alkaline developer can be used, but in addition, an inorganic alkali or an aqueous solution capable of developing a resist can be used. It is desirable to wash with water after developing the resist.

  As a developer that can be used in the present invention, a developer having a solubility in an organic EL layer forming material such as a light emitting layer forming material of 0.001 (g / g developer) or less at 25 ° C. and 1 atm. It is preferable to select a developing solution of 0.0001 (g / g developing solution) or less.

(Photoresist stripper)
Furthermore, as a photoresist stripping solution that can be used in the present invention, it is necessary not to dissolve the organic EL layer but to dissolve the photoresist layer, and the photoresist solvent as described above is used as it is. You can do it. Further, when a positive resist is used, it can be peeled off using the solution mentioned as the resist developer after UV exposure.

  Further, a strong alkaline aqueous solution, a solvent such as dimethylformamide, dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, a mixture thereof, or a commercially available resist stripping solution may be used. After the resist is peeled off, it may be rinsed with 2-propanol or the like and further rinsed with water.

(Patterning method)
Specifically, in the patterning by the photolithography method used in the present invention, when a positive photoresist is used, an organic EL layer is first formed on the entire surface, and the photoresist material is dissolved in the photoresist solvent on the organic EL layer. First, a photoresist layer is formed by applying and drying the photoresist solution thus prepared. Next, this photoresist layer is subjected to pattern exposure, and the exposed portion of the photoresist is developed with a resist developer as described above. This development leaves only the unexposed photoresist. And it is the method of patterning an organic EL layer by removing the organic EL layer of the part which is not coat | covered with a photoresist.

  The method for forming the entire surface of the organic EL layer as described above is the same as that for forming an ordinary organic EL layer and is not particularly limited. However, in addition to the vapor deposition method, an electrodeposition method, a melt of a material, a solution Alternatively, a spin coating method using a mixed solution, a casting method, a dipping method, a bar coating method, a blade coating method, a roll coating method, a gravure coating method, a flexographic printing method, a spray coating method and the like can be used.

  In the photolithography method used in the present invention, a photoresist is applied on the organic EL layer to be patterned as described above, exposed, developed, and then the portion of the organic where the photoresist is removed by dry etching is used. The EL layer may be removed.

  Usually, since the photoresist layer is formed much thicker than the organic EL layer, the organic EL layer can be removed by performing dry etching as a whole.

  In this case, the thickness of the photoresist layer is preferably in the range of 0.1 to 10 μm, and more preferably in the range of 0.5 to 5 μm. With such a film thickness, dry etching with high processing accuracy can be performed while maintaining the resist function of the photoresist.

  By combining the dry etching method with a part of the photolithography method in this way, it becomes possible to sharpen the edge of the etching, so the width of the non-uniform film thickness region existing at the edge of the pattern can be reduced. It becomes possible to make it narrower, and as a result, there is an effect that higher-definition patterning becomes possible.

  As the dry etching method used in the present invention, the dry etching is preferably reactive ion etching. By using reactive ion etching, the organic film undergoes a chemical reaction and becomes a compound with a low molecular weight, so that it can be vaporized and evaporated to be removed from the substrate. This is because processing becomes possible.

  In the present invention, it is preferable to use oxygen alone or a gas containing oxygen in the dry etching. By using oxygen alone or a gas containing oxygen, the organic film can be decomposed and removed by an oxidation reaction, unnecessary organic substances can be removed from the substrate, and processing with high etching accuracy and short time is possible. . Further, under this condition, the normally used oxide transparent conductive film such as ITO is not etched, and therefore, it is effective in that the electrode surface can be purified without impairing the electrode characteristics.

  Furthermore, in the present invention, it is preferable to use atmospheric pressure plasma for the dry etching. By using atmospheric pressure plasma, dry etching, which normally requires a vacuum apparatus, can be performed under atmospheric pressure, and the processing time and cost can be reduced. In this case, the etching can utilize the fact that the organic substance is oxidatively decomposed by oxygen in the atmosphere converted into plasma, but the gas composition of the reaction atmosphere may be arbitrarily adjusted by gas replacement and circulation.

  In the photolithography method used in the present invention, a photoresist is applied on the organic EL layer to be patterned, exposed, developed, and then the portion of the organic EL layer where the photoresist is removed by a solvent is removed. It is good also as patterning. As the solvent used at this time, it is necessary to dissolve or peel off the light emitting layer without peeling off the photoresist. In addition to the coating solvent for the light emitting layer, a solvent that satisfies the conditions can be selected.

  In the photolithography method used in the present invention, a photoresist is applied on the organic EL layer to be patterned, exposed, developed, and then the portion of the organic EL layer where the photoresist has been removed in an ultrasonic bath is removed. It is good also as patterning by doing. As the solvent to be used, it is necessary to dissolve or peel off the light emitting layer without peeling off the photoresist. In addition to the coating solvent for the light emitting layer, a solvent that satisfies the conditions can be selected.

  By using an ultrasonic bath in this way, in patterning of an organic EL layer using a photoresist, it is possible to perform patterning with high accuracy without problems such as thinning of each pattern and outflow of organic EL layer material. It is preferable in that high-precision patterning is possible in a short time. Note that this ultrasonic bath may also be used when developing the photoresist.

  In the present invention, the ultrasonic conditions used in this ultrasonic bath are preferably performed at 25 ° C. at an oscillation frequency of 20 to 100 kilohertz for 0.1 to 60 seconds. Patterning with high accuracy is possible in a short time.

(Buffer layer)
In the present invention, it is necessary that at least one of the EL layers sandwiched between two electrode layers as described above is an organic EL layer to be patterned, and as described above, the buffer layer or the light emitting layer is an organic EL layer. Preferably, it is formed by patterning. Hereinafter, the buffer layer will be described first.

  The buffer layer as used in the present invention refers to an organic substance, particularly an organic conductive pair, provided between the anode and the light emitting layer or between the cathode and the light emitting layer so that charge can be easily injected into the light emitting layer. It is a layer that contains. For example, it can be a conductive polymer having a function of increasing hole injection efficiency into the light emitting layer and flattening irregularities such as electrodes.

  When the conductivity of the buffer layer used in the present invention is high, it is desirable that the buffer layer be patterned in order to maintain the diode characteristics of the device and prevent crosstalk. Therefore, it is desirable to form by patterning according to the present invention. If the resistance of the buffer layer is high, the patterning may not be necessary. In the case of an element that can omit the buffer layer, the buffer layer may not be provided.

  In the present invention, when both the buffer layer and the light emitting layer are formed by patterning by photolithography as the organic EL layer, the material for forming the buffer layer is insoluble in the photoresist solvent and the solvent used for forming the light emitting layer. It is preferable to select a material that is insoluble in the photoresist stripping solution as the material for forming the buffer layer.

  On the other hand, when the light emitting layer is formed by vacuum film formation or the like and the layer patterned by the photolithography method as the organic EL layer is only the buffer layer, the material for forming the buffer layer is a photoresist solvent and a photoresist stripping solution. It is preferable to select a material that is insoluble in water.

  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, etc. An organic polymer film of the above, an organic compound film containing a Lewis acid, etc. are mentioned, but it is not particularly limited as long as the above-mentioned solubility conditions are satisfied, and the above conditions are obtained by reaction, polymerization or baking after film formation. May be satisfied. Moreover, when forming a light emitting layer by vacuum film forming etc., the buffer material, hole injection material, and hole transport material which are generally used can be used.

  In addition, the solvent used in forming the buffer layer in the present invention is not particularly limited as long as the buffer material is dispersed or dissolved. Therefore, it is necessary to use a buffer layer solvent that does not dissolve the photoresist material, more preferably a buffer layer solvent that does not dissolve the light emitting layer. As the buffer layer solvent that can be used in the present invention, a solvent having a resist material solubility of 0.001 (g / g solvent) or less at 25 ° C. and 1 atm is preferably selected, and more preferably 0.0001. (G / g solvent) The following solvent is selected. More preferably, the buffer layer solvent is selected so that the solubility of the light emitting material is 0.001 (g / g solvent) or less at 25 ° C. and 1 atm, particularly 0.0001 (g / g solvent). It is preferable to select the following solvents. For example, solvents such as water, alcohols such as methanol, ethanol, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone can be used. It is. Two or more solvents may be mixed and used.

  An example of patterning using such a photolithography method for the buffer layer will be specifically described with reference to FIG.

  FIG. 1 is a diagram showing a procedure for manufacturing a monochrome EL element by patterning a buffer layer and a light emitting layer by the method of the present invention. First, as shown in FIG. 1A, a buffer layer 3 is formed on the entire surface of the first electrode layer 2 patterned on the substrate 1. Next, as shown in FIG. 1B, a positive resist layer 4 is formed on the buffer layer 3 and prebaked. Next, as shown in FIG. 1C, UV pattern exposure 6 is performed by partially shielding the light with a mask 5. Next, as shown in FIG. 1D, development with a resist developer and washing with water remove the photoresist and the buffer layer in the exposed portion. Next, as shown in FIG. 1E, when the resist is stripped with a resist stripping solution, a pattern of the buffer layer 3 covering the first electrode layer 2 can be formed. Next, as shown in FIG. 1 (f), a light emitting layer 7 is formed on the entire surface of the first electrode layer 2 patterned on the substrate 1 and the buffer layer 3 provided on the first electrode layer 2. Next, as shown in FIG. 1G, a positive photoresist layer 4 is formed on the light emitting layer 7 and prebaked. Next, as shown in FIG. 1 (h), UV pattern exposure 6 is performed by partially shielding light with a mask 5. Next, as shown in FIG. 1 (i), when the resist is developed and washed with a resist developer, the photoresist in the exposed portion is removed. Next, as shown in FIG. 1 (j), when the luminescent layer is washed with a solvent, the patterned exposed luminescent layer 7 is removed. Next, as shown in FIG. 1 (k), the resist is stripped with a resist stripping solution. Finally, when the second electrode layer 8 is formed as shown in FIG. 1 (l), an EL element that emits EL light emission 9 toward the bottom of the figure can be manufactured.

(Light emitting layer)
Next, the light emitting layer as an organic EL layer formed by patterning according to the present invention will be described.

  A material for forming such a light emitting layer is not particularly limited as long as it includes a material emitting fluorescence and emits light. As a material for forming the light emitting layer, it can also have a light emitting function and a hole transport function and an electron transport function. Preferably, the material for forming the light emitting layer is the photoresist solvent, the photoresist developer, and It is a material that is insoluble in the photoresist stripping solution. In this case, it is preferable to use a material insoluble in the solvent used for forming the light emitting layer as the photoresist used when patterning the light emitting layer by photolithography.

  Examples of the material for forming the light emitting layer that can be used in the present invention include the following.

1. Dye-type materials Dye-type materials include cyclopentamine derivatives, tetraphenylbutadiene derivatives, triphenylamine derivatives, oxadiazol derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, silole derivatives, thiophene ring compounds Pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, trifumanylamine derivatives, oxadiazole dimers, pyrazoline dimers, and the like.

2. Metal complex materials As metal complex materials, aluminum quinolinol complex, benzoquinolinol beryllium complex, benzoxazole zinc complex, benzothiazole zinc complex, azomethyl zinc complex, porphyrin zinc complex, europium complex, etc. Examples thereof include a metal complex having Be or the like, or a rare earth metal such as Tb, Eu, or Dy, and having a oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, quinoline structure, or the like as a ligand.

3. Polymeric materials Polymeric materials include polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, etc., polyfluorene derivatives, polyvinylcarbazole derivatives, the above dye bodies, and metal complex light emitting materials Can be mentioned.

4). Doping Material Doping can be performed in the light emitting layer for the purpose of improving the light emission efficiency and changing the light emission wavelength. Examples of the doping material include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrene derivatives, styryl dyes, tetracene derivatives, pyrazoline derivatives, decacyclene, phenoxazone, and the like.

5. Solvent for coating the light-emitting layer When the solvent for coating the light-emitting layer is used with the buffer layer, it prevents the buffer layer and the light-emitting layer material from mixing and dissolving when forming the light-emitting layer, and maintains the original light-emitting characteristics of the light-emitting material. Therefore, it is desirable not to dissolve the buffer layer.

  From this point of view, it is preferable to select a solvent for the light emitting layer coating having a solubility in the buffer layer material of 25 ° C. or less and 0.001 (g / g solvent) or less at 1 atm, more preferably 0.0001 ( g / g solvent) The following solvents are preferably selected.

  Furthermore, the light-emitting layer coating solvent prevents the photoresist layer and the light-emitting layer material from being mixed or dissolved in the formation of the light-emitting layer for the second and subsequent colors, and is already patterned. It is desirable not to dissolve the photoresist in order to protect the light emitting layer.

  From such a viewpoint, it is preferable to select a solvent having a solubility in the photoresist of 25 ° C. or less and 0.001 (g / g solvent) or less at 1 atm, and more preferably 0.0001 (g / g). g Solvent) The following solvents are preferably selected. For example, when the buffer layer is dissolved in a polar solvent such as water or DMF, DMSO or alcohol and the photoresist is a general novolak positive resist, isomers of benzene, toluene and xylene and their mixtures, mesitylene, tetralin , P-cymene, cumene, ethylbenzene, diethylbenzene, butylbenzene, chlorobenzene, dichlorobenzene isomers and mixtures thereof, anisole, phenetol, butylphenyl ether, tetrahydrofuran, 2-butanone, Ether solvents such as 1,4-dioxane, diethyl ether, diisopropyl ether, diphenyl ether, dibenzyl ether, diglyme, dichloromethane, 1,1-dichloroethane, 1,2-dichloroethane Chloro-based solvents such as chlorobenzene, trichloroethylene, tetrachloroethylene, chloroform, carbon tetrachloride, 1-chloronaphthalene, cyclohexanone, etc., but other solvents that satisfy the conditions can be used. It may be.

  In the present invention, an EL element for full color display can be formed by using three kinds of such light emitting layers and patterning them. A method for forming such a light emitting layer will be specifically described with reference to the drawings.

  FIG. 2 is a diagram showing a procedure for manufacturing a full-color display EL element by patterning three color light-emitting layers by the method of the present invention. First, as shown in FIG. 2A, the patterned first electrode layer 22 and buffer layer 23 are formed on the substrate 21, and the blue light emitting layer 24 is formed on the entire surface thereof. Next, as shown in FIG. 2B, a positive resist 25 is applied over the entire surface. As shown in FIG. 2C, a portion where a blue light emitting layer is to be formed is masked 26, and the portion other than that portion is subjected to UV exposure 27. . When this is developed with a resist developer and washed with water, the resist in the exposed area is removed as shown in FIG. Further development with a solvent of the light emitting layer removes only the bare blue light emitting layer 24 as shown in FIG. 2E, leaving the resist and the blue light emitting layer 24 covered with the resist. Next, similarly to the formation of the blue light emitting layer, the green light emitting layer 28 is formed on the entire surface as shown in FIG. 2F, and the positive resist 25 is applied on the entire surface as shown in FIG. As shown in h), the portion for forming the blue and green light emitting layers is masked 26, and the other portion is subjected to ultraviolet exposure 27. When this is developed with a resist developer, washed with water, and further developed with a solvent of the light emitting layer, only the bare green light emitting layer 28 is removed as shown in FIG. 2 (i), and a portion covered with the resist remains. Further, similarly to the formation of the blue and green light emitting layers, a red light emitting layer 29 and a positive resist 25 are formed over the entire surface as shown in FIG. 2 (j), and blue, green and red are formed as shown in FIG. 2 (k). The portion where the light emitting layer is formed is masked, and the portion other than that portion is exposed to ultraviolet light. When this is developed with a resist developer, washed with water, and developed with the solvent of the light emitting layer, only the bare red light emitting layer 29 is removed as shown in FIG. 2 (l), and the portion covered with the resist remains. Further, when the stripping process is performed with the resist stripping solution, the upper layer is stripped from the portion where the resist is formed, and as shown in FIG. 2 (m), the light emitting layers of blue, green, and red are exposed and formed. . Finally, when the second electrode layer 30 is formed on these light emitting layers as shown in FIG. 2 (n), an EL element that emits EL light emission 31 below the figure can be manufactured.

(Other organic EL layers)
1. Charge Transport Layer The organic EL layer of the present invention can also include a charge injection layer. The charge injection layer includes a hole injection layer and / or an electron injection layer. These are not particularly limited as long as they are generally used for EL elements such as those described in JP-A-11-4011.

  Note that the light-emitting material, the hole transport material, or the electron transport material constituting the above layers may be used alone or in combination. The layer containing the same material may be a single layer or a plurality of layers.

2. Electrode layer In the present invention, the electrode layer is not limited as long as it is usually used for EL elements. The electrode layer provided on the substrate first is the first electrode layer, and the electrode layer provided after the organic EL layer is formed is the second electrode layer. Sometimes called. These electrode layers are composed of an anode and a cathode, and either the anode or the cathode is transparent or translucent, and the anode is preferably a conductive material having a large work function so that holes can be easily injected. . A plurality of materials may be mixed. Each of the electrode layers preferably has a resistance as small as possible. Generally, a metal material is used, but an organic material or an inorganic compound may be used.

  Preferable anode materials include, for example, ITO, isodium oxide, and gold. Preferred cathode materials include, for example, magnesium alloys (MgAg, etc.), aluminum alloys (AlLi, AlCa, AlMg, etc.), metallic calcium, and metals with a low work function.

3. Insulating layer In the EL device of the present invention, the insulating layer emits light in order to cover the patterned edge portion of the first electrode layer formed on the substrate and the non-light emitting portion of the device and prevent a short circuit in a portion unnecessary for light emission. It may be provided in advance so that the portion becomes an opening. By doing in this way, the defect by the short circuit of an element, etc. is reduced, and the element which carries out the long life and stable light emission is obtained.

  As is generally known, for example, a UV curable resin material or the like can be used to form a pattern with a film thickness of about 1 μm. However, when the organic EL layer is patterned by dry etching of the present invention, the insulating layer is Desirably, the film has a dry etching resistance, and when the resistance is small, it is preferable to form the film with a film thickness of 1 μm or more, for example, 1.5 to 10 μm so as not to be lost by dry etching, more preferably 2 to 5 μm. It is to form with the film thickness of.

B. EL Element Next, the EL element of the present invention will be described. The EL element of the present invention has three embodiments described below, and any of them can be manufactured by the above-described EL element manufacturing method. Hereinafter, each embodiment will be described.

(First embodiment)
The first embodiment of the EL device of the present invention is an EL device having at least one patterned organic EL layer, and includes any of a partition wall, a composition for assisting patterning, and a surface treatment for assisting patterning. It is characterized by not.

  Although the EL element of this embodiment has a patterned organic EL layer, it does not have any of a partition wall, a composition that assists patterning, and a surface treatment that assists patterning. Therefore, it has the advantage of being advantageous in terms of cost.

  In this embodiment, the organic EL layer is preferably formed of a polymer material that cannot be formed by vapor deposition. Moreover, it is preferable that the said organic EL layer is a light emitting layer in which patterning is especially essential.

  Other configurations are the same as those described in the above-described EL element manufacturing method, and thus the description thereof is omitted here.

(Second embodiment)
A second embodiment of the EL element of the present invention is an EL element having at least one organic EL layer, wherein the organic EL layer is a patterned light emitting layer, and is formed at an end of the patterned light emitting layer. The width of the formed non-uniform film thickness region is 15 μm or less, preferably 10 μm or less, and particularly preferably 7 μm or less. Here, the “thickness non-uniform region” refers to a region that exists in the edge portion and has a thickness of 90% or less of the average thickness of the flat portion.

  In the EL element obtained by the EL element manufacturing method as described above, the light emitting layer is patterned by a photolithography method, and the light emitting layer is different from the ink jet method or the like in that the thickness is uniform and the periphery of the light emitting layer is high. The edge shape of the part can be freely controlled according to the etching conditions. Therefore, it is possible to adjust the width of the edge region, that is, the non-uniform film thickness region referred to in the present invention, and the edged shape, that is, the width of the non-uniform film thickness region is narrowed or the edge is tapered. In other words, the width of the non-uniform film thickness region can be increased.

  On the other hand, the non-uniform thickness region of the light emitting layer patterned by the conventional ink jet method usually has a width exceeding 15 μm. Therefore, it has been difficult to precisely arrange pixels constituting each color formed by such patterning.

  Here, FIG. 3 shows a non-uniform film thickness region, that is, an edge portion in the light-emitting layer of the EL element of the present invention, and FIG. 4 shows a non-uniform film thickness region of the light-emitting layer patterned by the conventional ink jet method. It is shown. As is clear from these figures, the nonuniform thickness region of the edge portion of the light emitting layer patterned by the conventional ink jet method is wide, but the width of the nonuniform thickness region in the light emitting layer of the EL element of the present invention is It is quite narrow.

  In the EL element of this embodiment, since the width of the non-uniform thickness region at the edge of the light emitting layer is equal to or smaller than the above-described value, the distance between the pixels can be reduced. It has the advantage that it can be arranged and can be an EL element capable of obtaining a high-quality image.

  Also in this embodiment, the material forming the light emitting layer is preferably an organic polymer material that cannot be formed by vapor deposition. Further, the light emitting layer has at least three layers, and is preferably configured so as to obtain a full color image. Other configurations, materials, and the like are the same as those in the EL element manufacturing method described above, and thus the description thereof is omitted here.

(Third embodiment)
A third embodiment of the EL device of the present invention is an EL device having at least one organic EL layer, wherein the organic EL layer is a plurality of patterned light emitting layers capable of emitting a plurality of colors, The EL element is characterized in that the distance between adjacent light emitting layers emitting different colors is 30 μm or less, preferably 20 μm or less, particularly preferably 15 μm or less.

  Here, the distance between the light emitting layers refers to the space between the pixels composed of the patterned light emitting layers.

  The ink jet method, which is best known for wet patterning of the light-emitting layer, is used to define the uniformity of the edge of the film, the unstable landing position of the ink, and the range of wet ink spreading. The distance between the patterned light emitting layers is generally at least 40 μm or more due to the necessity of providing an ink bank or forming an ink repellent pattern. Therefore, it is impossible to pattern an element having a small pixel pitch, for example, 42 μm or less.

  On the other hand, the EL device of this embodiment is an EL device capable of producing a polymer or low-molecular light emitting layer by wet film formation, and the patterning accuracy of the light emitting layer is high, and the edge of the patterned light emitting layer Unlike the case where the portion is formed by drying, a technique of removing unnecessary portions by dissolution or etching is used. Therefore, the uniformity of the film of the light emitting layer is high, and there is only an inclined region of, for example, about 5 μm from the patterned end. It is. Therefore, when a full-color display is manufactured, the distance between each pixel that is a light emitting portion can be reduced, and thereby the aperture ratio can be increased. In addition, since the distance between the pixels can be reduced, each pixel can be densely arranged.

  In this embodiment as well as the second embodiment, the material for forming the light emitting layer is preferably an organic polymer material that cannot be formed by vapor deposition. Further, the light emitting layer has at least three layers, and is preferably configured so as to obtain a full color image. Other configurations, materials, and the like are the same as those in the EL element manufacturing method described above, and thus the description thereof is omitted here.

(Other)
In the EL elements shown in the first embodiment, the second embodiment, and the third embodiment, at least the substrate, the electrode layer formed in a pattern on the substrate, the edge portion of the electrode layer, and the element It is preferable to have a structure having an insulating layer covering the non-light emitting portion.

  This is because, by covering the edge portion of the electrode layer formed in a pattern in this way with an insulating layer, defects due to short-circuiting of the elements as described above can be reduced.

  Here, the substrate used is not particularly limited as long as it is a substrate made of glass or the like usually used in EL elements.

  In addition, the electrode layer and the insulating layer are the same as those described in the column of the EL element manufacturing method, and thus the description thereof is omitted here.

(Specific material combinations)
Examples of suitable material combinations that can perform patterning of the EL element in the present invention using the solubility in a specific solution as described above are as follows.

Buffer layer: polyalkylthiophene derivative, polyaniline derivative Light emitting layer: polyparaphenylene vinylene derivative, polyfluorene derivative,
Polyvinylcarbazole derivative Photoresist: Positive resist (nopolak resin)
Photoresist solvent: cellosolve, cellosolve acetate Photoresist developer: organic alkali developer Photoresist stripper: cellosolve, cellosolve acetate, acetone Light emitting layer forming solvent: xylene, toluene On the other hand, EL element materials and photoresist materials that are commonly used However, for example, the following combinations are not suitable in the present invention (however, each material can be a suitable material in combination with other material systems).

Buffer layer: polyalkylthiophene derivative, polyaniline derivative Light emitting layer: TPD / Alq3 having the following structure, polyvinylcarbazole + oxadiazole derivative + fluorescent dye

Photoresist: Positive resist (Novolac resin)
Photoresist solvent: cellosolve, cellosolve acetate Photoresist developer: organic alkali developer Photoresist stripper: cellosolve, cellosolve acetate, acetone Luminescent layer forming solvent: dichloroethane (in the case of TPD / Alq3, vacuum film formation)
In the present invention, it is inappropriate to use polyvinyl carbazole + oxadiazole derivative + fluorescent dye for the light emitting layer because the oxadiazole derivative and the fluorescent dye are eluted at the time of resist film formation and peeling. It is also inappropriate to use TPD / Alq3 for the light emitting layer because TPD and Alq3 are eluted at the time of film formation and peeling of the resist, and TPD is crystallized by a heating process in photolithography.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

  The following examples further illustrate the invention.

[Example 1: When the light emitting layer is a single layer]
(Buffer layer patterning)
A patterned ITO substrate having a thickness of 3 inches and a thickness of 1.1 mm was washed to obtain a substrate and a first electrode layer used in this example.

  Buffer layer coating liquid having the following chemical structure (poly (3,4) ethylenedioxythiophene / polystyrene sulfonate (PEDT / PSS): 0.5 ml of Bayer P (BaytronP) was taken and dropped onto the center of the substrate. Spin coating was performed.

  The buffer layer was formed by holding at 2500 rpm for 20 seconds, and dried at 150 ° C. for 5 minutes. As a result, the film thickness was 800 angstroms.

  2 ml of a positive photoresist solution (manufactured by Tokyo Ohka Kogyo Co., Ltd .; OFPR-800) was taken and dropped onto the center of the substrate for spin coating. The resist layer was formed by holding at 500 rpm for 10 seconds and then holding at 2000 rpm for 20 seconds. As a result, the film thickness was about 1 μm. Pre-baking was performed at 80 ° C. for 30 minutes. Thereafter, an exposure mask was set on the alignment exposure machine, and UV exposure was performed on the portion where the buffer layer was to be removed. After developing with a resist developer (manufactured by Tokyo Ohka Co., Ltd .; NMD-3) for 20 seconds, it was washed with water to remove the photoresist and buffer layer in the exposed area. After post-baking at 120 ° C. for 30 minutes, all the photoresist was removed with acetone, and a buffer layer insoluble in acetone was formed into an arbitrary pattern.

(Light emitting layer patterning)
2 ml of a 1 wt% xylene solution of a polyparaphenylene vinylene derivative luminescent polymer MEH-PPV having the following chemical structure was taken on the substrate on which the buffer layer was patterned, and dropped onto the center of the substrate to perform spin coating. .

  The light emitting layer was formed by holding at 2000 rpm for 10 seconds, and dried at 80 ° C. for 1 hour. As a result, the film thickness was 800 angstroms.

  2 ml of a positive photoresist solution (manufactured by Tokyo Ohka Kogyo Co., Ltd .; OFPR-800) was taken and dropped onto the center of the substrate for spin coating. The resist layer was formed by holding at 500 rpm for 10 seconds and then holding at 2000 rpm for 20 seconds. As a result, the film thickness was about 1 μm. Pre-baking was performed at 80 ° C. for 30 minutes. Then, it set with the exposure mask to the alignment exposure machine, and exposed the ultraviolet-ray to the part which wants to remove a light emitting layer. After developing with a resist developer (manufactured by Tokyo Ohka Co., Ltd .; NMD-3) for 20 seconds, it was washed with water to remove the photoresist in the exposed area. After post-baking at 90 ° C. for 30 minutes, the light-emitting layer where the photoresist was removed with toluene was removed. All the photoresist was removed with acetone, and a light emitting layer insoluble in acetone was formed in an arbitrary pattern.

  After drying at 90 ° C. for 1 hour, Ca was deposited as a second electrode layer (upper electrode) with a thickness of 500 Å on the obtained substrate, and Ag was further deposited as a protective layer with a thickness of 2500 Å. An EL element was prepared.

  The resolution of the obtained pattern depends on the resolution of the positive resist, but in this example, the resolution cannot be achieved by the conventional vapor deposition mask method and ink jet method. A high-definition line of 10 μm could be formed.

(Evaluation of light emission characteristics of EL element)
The ITO electrode (first electrode layer) side was connected to the anode, the Ag electrode (second electrode layer) side was connected to the cathode, and a direct current was applied by a source meter. Light emission was observed when 10 V was applied, and it could be evaluated that there was no deterioration in the light emission starting voltage due to patterning using a photolithography method. Further, no decrease in luminous efficiency was observed. Furthermore, by patterning the buffer layer, the insulation between the anode lines can be improved and the crosstalk occurrence rate is reduced.

[Example 2: When the light emitting layer has three layers]
The buffer layer was patterned in the same manner as in Example 1.

  2 ml of 1 wt% xylene solution of polyparaphenylene vinylene derivative light emitting polymer MEH-PPV was taken on the substrate on which the buffer layer was patterned as the first light emitting layer, and dropped onto the center of the substrate to perform spin coating. . The light emitting layer was formed by holding at 2000 rpm for 10 seconds. As a result, the film thickness was 800 angstroms.

  2 ml of a positive photoresist solution (manufactured by Tokyo Ohka Kogyo Co., Ltd .; OFPR-800) was taken and dropped onto the center of the substrate for spin coating. The resist layer was formed by holding at 500 rpm for 10 seconds and then holding at 2000 rpm for 20 seconds. As a result, the film thickness was about 1 μm. Pre-baking was performed at 80 ° C. for 30 minutes. Then, it set to the alignment exposure machine with the exposure mask, and ultraviolet-ray exposure was performed to the part which wants to remove light emitting layers other than the light emission part of 1st color. After developing with a resist developer (manufactured by Tokyo Ohka Co., Ltd .; NMD-3) for 20 seconds, it was washed with water to remove the photoresist in the exposed area. After post-baking at 90 ° C. for 30 minutes, the light emitting layer where the photoresist has been removed with toluene is removed, the first light emitting part is protected by the photoresist, and the buffer layers of the second and third light emitting parts are An exposed substrate was obtained.

  As the second light-emitting layer, 2 ml of a 1 wt% xylene solution of polyparaphenylene vinylene derivative light-emitting polymer MEH-PPV was taken and dropped onto the center of the substrate to perform spin coating. The light emitting layer was formed by holding at 2000 rpm for 10 seconds. As a result, the film thickness was 800 angstroms.

  2 ml of a positive photoresist solution (Tokyo PR Corporation OFPR-800) was taken and dropped onto the center of the substrate to perform spin coating. The resist layer was formed by holding at 500 rpm for 10 seconds and then holding at 2000 rpm for 20 seconds. As a result, the film thickness was about 1 μm. Pre-baking was performed at 80 ° C. for 30 minutes. Then, it set to the alignment exposure machine with the exposure mask, and exposed the ultraviolet-ray to the part which wants to remove light emitting layers other than the 1st, 2nd light emission part. After developing with a resist developer (manufactured by Tokyo Ohka Co., Ltd .; NMD-3) for 20 seconds, it was washed with water to remove the photoresist in the exposed area. After post-baking at 90 ° C. for 30 minutes, the light emitting layer where the photoresist has been removed with toluene is removed, the first and second light emitting parts are protected with photoresist, and the buffer layer of the third light emitting part is An exposed substrate was obtained.

  As the third light-emitting layer, 2 ml of a 1 wt% xylene solution of the polybaraphenylene vinylene derivative light-emitting polymer MEH-PPV was taken and dropped onto the center of the substrate to perform spin coating. The light emitting layer was formed by holding at 2000 rpm for 10 seconds. As a result, the film thickness was 800 angstroms.

  2 ml of a positive resist solution (OFPR-800 manufactured by Tokyo Ohka Kogyo Co., Ltd.) was taken and dropped onto the center of the substrate to perform spin coating. The resist layer was formed by holding at 500 rpm for 10 seconds and then holding at 2000 rpm for 20 seconds. As a result, the film thickness was about 1 μm. Pre-baking was performed at 80 ° C. for 30 minutes. Thereafter, the wafer was set in an alignment exposure machine together with an exposure mask, and the portion where the light emitting layer other than the first to third light emitting portions was to be removed was exposed to ultraviolet rays. After developing with a resist developer (NMD-3 manufactured by Tokyo Ohka Kogyo Co., Ltd.) for 20 seconds, it was washed with water to remove the photoresist in the exposed area. After post-baking at 90 ° C. for 30 minutes, the light emitting layer where the photoresist was removed with toluene was removed to obtain a substrate in which the first to third light emitting portions were protected with the photoresist. Thereafter, all the photoresist was removed with acetone.

  After drying at 90 ° C. for 1 hour, Ca was then deposited as a second electrode layer (upper electrode) with a thickness of 500 angstroms, and Ag was deposited as a protective layer with a thickness of 2500 angstroms on the obtained substrate. An EL element was produced.

  Although the resolution of the obtained pattern depends on the resolution of the positive resist, in this example, a high-definition line of 10 μm, which is a resolution that cannot be realized by the conventional vapor deposition mask method and inkjet method, could be formed.

(Evaluation of light emission characteristics of EL element)
The ITO electrode (first electrode layer) side was connected to the anode, the Ag electrode (second electrode layer) side was connected to the cathode, and a direct current was applied by a source meter. Light emission was recognized from each of the first to third light emitting portions when 10 V was applied, and it was evaluated that there was no deterioration in the light emission starting voltage due to patterning using a photolithography method. Further, no decrease in luminous efficiency was observed. Furthermore, by patterning the buffer layer, the insulation between the anode lines can be improved and the crosstalk occurrence rate is reduced.

[Example 3: Change of solvent]
An EL device was produced in the same manner as in Example 1 except that polyvinylcarbazole represented by the following formula was used for the light emitting layer and toluene was used for the light emitting layer solvent.

  Although the resolution of the obtained pattern depends on the resolution of the positive resist, in this example, a high-definition line of 10 μm, which is a resolution that cannot be realized by the conventional vapor deposition mask method and inkjet method, could be formed.

(Evaluation of light emission characteristics of EL element)
The ITO electrode (first electrode layer) side was connected to the anode, the Ag electrode (second electrode layer) side was connected to the cathode, and a direct current was applied by a source meter. Light emission was observed when 15 V was applied, and it could be evaluated that there was no deterioration in the light emission starting voltage due to patterning using a photolithography method. Further, no decrease in luminous efficiency was observed. Furthermore, by patterning the buffer layer, the insulation between the anode lines can be improved and the crosstalk occurrence rate is reduced.

[Example 4: Patterning by dry etching]
(Buffer layer deposition)
A patterned ITO substrate having a thickness of 3 inches and a thickness of 1.1 mm was washed to obtain a substrate and a first electrode layer used in this example. 0.5 ml of a buffer layer coating solution (manufactured by Bayer; BaytronP) was taken and dropped onto the center of the substrate to perform spin coating. The layer was formed by holding at 2500 rpm for 20 seconds. As a result, the film thickness was 800 angstroms.

(Light emitting layer patterning)
2 ml of a 1 wt% xylene solution of the polyparaphenylene vinylene derivative luminescent polymer MEH-PPV was taken on the substrate on which the buffer layer was patterned, and dropped onto the center of the substrate to perform spin coating. The layer was formed by holding at 2000 rpm for 10 seconds. As a result, the film thickness was 800 angstroms.

  2 ml of a positive photoresist solution (manufactured by Tokyo Ohka Kogyo Co., Ltd .; OFPR-800) was taken and dropped onto the center of the substrate for spin coating. The layer was formed by holding at 500 rpm for 10 seconds and then holding at 2000 rpm for 20 seconds. As a result, the film thickness was about 1 μm. Pre-baking was performed at 80 ° C. for 30 minutes. Then, it set with the exposure mask to the alignment exposure machine, and exposed the ultraviolet-ray to the part which wants to remove a light emitting layer. After developing with a resist developer (manufactured by Tokyo Ohka Co., Ltd .; NMD-3) for 20 seconds, it was washed with water to remove the photoresist in the exposed area.

  After post-baking at 120 ° C. for 30 minutes, oxygen plasma treatment was performed at a pressure of 150 mTorr and a power of 150 W for 20 minutes. Since the photoresist was 5 times thicker than the buffer layer and the light emitting layer, only the light emitting layer and the buffer layer that were not protected by the photoresist were peeled off, and the ITO electrode was exposed. A substrate in which the first light emitting portion was protected with a photoresist was obtained.

  A buffer layer coating solution was spin-coated on the obtained substrate to obtain an 800 Å buffer layer. Next, 2 ml of 1 wt% xylene solution of polyparaphenylene vinylene derivative light emitting polymer MEH-PPV was taken as a second light emitting layer and dropped on the center of the substrate to perform spin coating. The layer was formed by holding at 2000 rpm for 10 seconds. As a result, the film thickness was 800 angstroms.

  2 ml of a positive photoresist solution (Tokyo PR Corporation OFPR-800) was taken and dropped onto the center of the substrate to perform spin coating. The layer was formed by holding at 500 rpm for 10 seconds and then holding at 2000 rpm for 20 seconds. As a result, the film thickness was about 1 μm. Pre-baking was performed at 80 ° C. for 30 minutes. Then, it set to the alignment exposure machine with the exposure mask, and ultraviolet-ray exposure was performed to the part which wants to remove light emitting layers other than the light emission part of 1st color. After developing with a resist developer (NMD-3 manufactured by Tokyo Ohka Kogyo Co., Ltd.) for 20 seconds, it was washed with water to remove the photoresist in the exposed area.

  After post-baking at 120 ° C. for 30 minutes, oxygen plasma treatment was performed at a pressure of 150 mTorr and a power of 150 W for 20 minutes. Since the photoresist was 5 times thicker than the buffer layer and the light emitting layer, only the light emitting layer and the buffer layer that were not protected by the photoresist were peeled off, and the ITO electrode was exposed. A substrate in which the first and second light emitting portions were protected with a photoresist was obtained.

  A buffer layer coating solution was spin-coated on the obtained substrate to obtain an 800 Å buffer layer. Next, 2 ml of a 1 wt% xylene solution of polyparaphenylene vinylene derivative light emitting polymer MEH-PPV was taken as a third light emitting layer and dropped onto the center of the substrate to perform spin coating. The layer was formed by holding at 2000 rpm for 10 seconds. As a result, the film thickness was 800 angstroms.

  2 ml of a positive photoresist solution (manufactured by Tokyo Ohka Kogyo Co., Ltd .; OFPR-800) was taken and dropped onto the center of the substrate for spin coating. The layer was formed by holding at 500 rpm for 10 seconds and then holding at 2000 rpm for 20 seconds. As a result, the film thickness was about 1 μm. Pre-baking was performed at 80 ° C. for 30 minutes. Then, it set to the alignment exposure machine with the exposure mask, and ultraviolet-ray exposure was performed to the part which wants to remove light emitting layers other than the light emission part of 1st color. After developing with a resist developer (manufactured by Tokyo Ohka Co., Ltd .; NMD-3) for 20 seconds, it was washed with water to remove the photoresist in the exposed area.

  After post-baking at 120 ° C. for 30 minutes, oxygen plasma treatment was performed at a pressure of 150 mTorr and a power of 150 W for 20 minutes. Since the photoresist was 5 times thicker than the buffer layer and the light emitting layer, only the light emitting layer and the buffer layer that were not protected by the photoresist were peeled off. A substrate in which the first to third light emitting portions were protected with a photoresist was obtained. Thereafter, all the photoresist was removed with acetone.

  After drying at 100 ° C. for 1 hour, Ca was deposited as a second electrode layer (upper electrode) with a thickness of 500 Å on the obtained substrate, and Ag was further deposited as a protective layer with a thickness of 2500 Å. An EL element was produced.

(Evaluation of light emission characteristics of EL element)
The ITO electrode side was connected to the positive electrode, the Ag electrode side was connected to the negative electrode, and a direct current was applied by a source meter. Light emission was recognized from each of the first to third light emitting portions when 10 V was applied.

[Example 5: Use of atmospheric plasma]
A device was fabricated in the same manner as in Example 4 except that atmospheric pressure plasma was used instead of the oxygen plasma treatment. Pattern formation was possible as in Example 4, and light emission was observed from each of the first to third light emitting portions.

[Example 6: Use of ultrasonic bath]
(Buffer layer deposition)
A patterned ITO substrate having a thickness of 6 inches and a thickness of 1.1 mm was washed to obtain a substrate and a first electrode layer of the present invention. 0.5 ml of a buffer layer coating solution (BaytronP (Chemical Formula 1) manufactured by Bayer) was taken and dropped onto the center of the substrate to perform spin coating. The layer was formed by holding at 2500 rpm for 20 seconds. As a result, the film thickness was 800 angstroms.

  2 ml of a positive photoresist solution (Tokyo PR Corporation OFPR-800) was taken and dropped onto the center of the substrate to perform spin coating. The layer was formed by holding at 500 rpm for 10 seconds and then holding at 2000 rpm for 20 seconds. As a result, the film thickness was about 1 μm. Pre-baking was performed at 80 ° C. for 30 minutes. Then, it set with the exposure mask to the alignment exposure machine, and ultraviolet-exposed to the part which wants to remove a buffer layer. After developing with a resist developer (NMD-3, manufactured by Tokyo Ohka Kogyo Co., Ltd.) for 20 seconds, it was washed with water to remove the photoresist and buffer layer in the exposed area. After post-baking at 120 ° C. for 30 minutes, all the photoresist was removed with acetone, and a buffer layer insoluble in acetone was formed into an arbitrary pattern.

(Light-emitting layer deposition)
Spin coating is performed by taking 2 ml of 1 wt% xylene solution of polyparaphenylene vinylene derivative light emitting polymer MEH-PPV on the substrate on which the buffer layer is patterned as the first light emitting layer, and dropping it on the center of the substrate. It was. The layer was formed by holding at 2000 rpm for 10 seconds. As a result, the film thickness was 800 angstroms.

  2 ml of a positive photoresist solution (Tokyo PR Corporation OFPR-800) was taken and dropped onto the center of the substrate to perform spin coating. The layer was formed by holding at 500 rpm for 10 seconds and then holding at 2000 rpm for 20 seconds. As a result, the film thickness was about 1 μm. Pre-baking was performed at 80 ° C. for 30 minutes. Then, it set to the alignment exposure machine with the exposure mask, and ultraviolet-ray exposure was performed to the part which wants to remove light emitting layers other than the light emission part of 1st color. After developing with a resist developer (NMD-3 manufactured by Tokyo Ohka Kogyo Co., Ltd.) for 20 seconds, it was washed with water to remove the photoresist in the exposed area. After post-baking at 120 ° C. for 30 minutes, the light emitting layer where the photoresist was removed with toluene in an ultrasonic bath was removed to obtain a substrate in which the first light emitting portion was protected with the photoresist.

  As a second light emitting layer, 2 ml of 1 wt% xylene solution of polyparaphenylene vinylene derivative light emitting polymer MEH-PPV was taken and dropped on the center of the substrate to perform spin coating. The layer was formed by holding at 2000 rpm for 10 seconds. As a result, the film thickness was 800 angstroms. By peeling off the photoresist with acetone, the second light emitting layer was peeled off together with the photoresist formed on the patterned first light emitting layer to expose the patterned first light emitting layer.

  2 ml of a positive photoresist solution (Tokyo PR Corporation OFPR-800) was taken and dropped onto the center of the substrate to perform spin coating. The layer was formed by holding at 500 rpm for 10 seconds and then holding at 2000 rpm for 20 seconds. As a result, the film thickness was about 1 μm. Pre-baking was performed at 80 ° C. for 30 minutes. Then, it set to the alignment exposure machine with the exposure mask, and exposed the ultraviolet-ray to the part which wants to remove light emitting layers other than the light emission part of a 1st color and a 2nd color. After developing with a resist developer (NMD-3 manufactured by Tokyo Ohka Kogyo Co., Ltd.) for 20 seconds, it was washed with water to remove the photoresist in the exposed area. After post-baking at 120 ° C. for 30 minutes, the light-emitting layer where the photoresist was removed with toluene in an ultrasonic bath was removed to obtain a substrate in which the first and second light-emitting portions were protected with the photoresist. .

  As a third light emitting layer, 2 ml of 1 wt% xylene solution of polyparaphenylene vinylene derivative light emitting polymer MEH-PPV was taken and dropped on the center of the substrate to perform spin coating. The layer was formed by holding at 2000 rpm for 10 seconds. As a result, the film thickness was 800 angstroms. By stripping the photoresist with acetone, the third light emitting layer is stripped together with the photoresist formed on the patterned first and second light emitting layers, and the patterned first and second light emitting layers are peeled off. The layer was exposed.

  2 ml of a positive photoresist solution (Tokyo PR Corporation OFPR-800) was taken and dropped onto the center of the substrate to perform spin coating. The layer was formed by holding at 500 rpm for 10 seconds and then holding at 2000 rpm for 20 seconds. As a result, the film thickness was about 1 μm. Pre-baking was performed at 80 ° C. for 30 minutes. Then, it set to the alignment exposure machine with the exposure mask, and exposed to the part which wants to remove light emitting layers other than the 1st thru | or 3rd light emission part, and exposed to ultraviolet rays. After developing with a resist developer (NMD-3 manufactured by Tokyo Ohka Kogyo Co., Ltd.) for 20 seconds, it was washed with water to remove the photoresist in the exposed area. After post-baking at 120 ° C. for 30 minutes, the light emitting layer where the photoresist was removed with toluene in an ultrasonic bath was removed to obtain a substrate in which the first to third light emitting portions were protected with the photoresist. . Thereafter, all of the photoresist was removed with acetone to expose the patterned light emitting layer.

  After drying at 100 ° C. for 1 hour, Ca was deposited as a second electrode layer (upper electrode) with a thickness of 500 Å on the obtained substrate, and Ag was further deposited as a protective layer with a thickness of 2500 Å. An EL element was produced.

(Evaluation of light emission characteristics of EL element)
The ITO electrode side was connected to the positive electrode, the Ag electrode side was connected to the negative electrode, and a direct current was applied by a source meter. Light emission was recognized from each of the first to third light emitting portions when 10 V was applied.

[Example 7: Formation of insulating layer]
A patterned ITO substrate having a thickness of 3 inches and a thickness of 1.1 mm was washed to obtain a substrate and a first electrode layer. At this time, the ITO pattern had a line of 84 μm and a space of 16 μm. An insulating layer having a film thickness of 5 μm was formed on the space portion and the end portion of ITO (in 5 μm increments) with a negative resist made of an insulating UV curable resin having a width of 26 μm. Otherwise, an EL element was formed in the same manner as in Example 4.

  Even after patterning for forming the first, second and third light emitting portions, the insulating layer does not lose its function as an insulating layer, and light emission is recognized from each of the first to third light emitting portions. It was. Therefore, it was found that even if an insulating layer was formed, a pattern could be formed as in the case of Example 4.

An example of the manufacturing method of the EL device of the present invention is a process chart showing a procedure for manufacturing a monochrome EL device by patterning a buffer layer. FIG. 9 is a process diagram showing another example of the method for manufacturing an EL element according to the present invention and illustrating a procedure for manufacturing a full-color display EL element by patterning a light emitting layer of three colors. It is an expanded sectional view which expands and shows the cross section of the edge part of the light emitting layer in the EL element of this invention. It is an expanded sectional view which expands and shows the cross section of the edge part of the light emitting layer formed by the conventional inkjet method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base | substrate 3 ... Buffer layer 4 ... Positive type photoresist layer 7 ... Light emitting layer 23 ... Buffer layer 24 ... Blue light emitting layer 25 ... Positive type photoresist layer 28 ... Green light emitting layer 29 ... Red light emitting layer

Claims (5)

An electroluminescent device having at least one patterned organic electroluminescent layer, wherein the electroluminescent device does not have any of a partition wall, a composition for assisting patterning, and a surface treatment for assisting patterning. Electroluminescent element. An electroluminescent device having at least one organic electroluminescent layer, wherein the organic electroluminescent layer is a patterned light emitting layer, and is formed at an end of the patterned light emitting layer An electroluminescent device characterized in that the width of the non-uniform thickness region is 15 μm or less. An electroluminescent device having at least one organic electroluminescent layer, wherein the organic electroluminescent layer is a plurality of patterned light emitting layers capable of emitting a plurality of colors and adjacent to each other. An electroluminescent element characterized in that a distance between light emitting layers emitting colors is 30 μm or less. 2. The apparatus according to claim 1, further comprising: at least a substrate; an electrode layer formed in a pattern on the substrate; and an insulating layer formed so as to cover an edge portion of the electrode layer and a non-light-emitting portion of the element. The electroluminescent device according to any one of claims 1 to 3. The electroluminescent device according to any one of claims 1 to 4, wherein the organic electroluminescent layer includes at least a buffer layer.

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