JP2008204807A - Manufacturing method of organic electroluminescent element and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of quickly manufacturing a long-life and high-efficiency organic EL element through a fine drying process, with each pixel giving out uniform light emission without any non-emission ones or current leak, and a display device. <P>SOLUTION: The manufacturing method of the organic electroluminescent element provided with a first electrode (2), a second electrode (7) set in opposition to the first electrode (2), and organic luminescent medium layers at least containing an organic luminescent layer (6) between the first electrode (2) and the second electrode (7) dries at least one layer among the organic luminescent medium layers in a letterpress contact drying method. The display device uses the organic electroluminescent element manufactured in the above method. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an organic electroluminescence (EL) element and a display device. More specifically, the present invention relates to a method and a display device for quickly producing a long-life and high-efficiency organic EL element that emits light uniformly in each pixel and does not generate a non-light emitting portion or current leak in a drying process of the organic EL element. .

  An organic light emitting device has a structure in which an organic light emitting layer exhibiting at least an electroluminescence phenomenon is sandwiched between an electrode as an anode and an electrode as a cathode, and when a voltage is applied between the electrodes, It is a self-luminous device in which an organic light emitting layer emits light by injecting holes and electrons into the light emitting layer and recombining the holes and electrons in the organic light emitting layer.

  Further, for the purpose of increasing luminous efficiency, a hole injection layer, a hole transport layer and / or an electron transport layer and an electron injection between the organic light emitting layer and the cathode are provided between the anode and the organic light emitting layer. A layer or the like is appropriately selected and provided. The organic light emitting layer and these hole injection layer, hole transport layer, electron transport layer, electron injection layer and the like are collectively called an organic light emitting medium layer.

  The luminous efficiency and luminance depend on the film thickness of each layer, and it is necessary to form a thin film of about 100 nm. Furthermore, in order to make this a display panel, it is necessary to pattern it with high definition.

  The material for forming the organic light emitting medium layer includes a low molecular material and a high molecular material. Generally, a low molecular material is formed into a thin film by a vacuum deposition method or the like, and a fine pattern mask is used for patterning. However, there is a problem that the patterning accuracy is less likely to increase as the substrate becomes larger. In addition, since the film is formed in a vacuum, there is a problem that the throughput is poor.

  Therefore, recently, a method of forming a thin film by a wet process has been attempted in which a polymer material is dissolved in a solvent to form a coating solution. When the organic light emitting medium layer is formed by a wet process using a coating liquid of a polymer material, a two-layer structure in which a hole transport layer and an organic light emitting layer are laminated from the anode side is generally used.

  Further, there is a problem of improving the device characteristics by inserting a third functional layer having an electronic blocking function between the hole transporting layer and the light emitting layer to solve the problem of deterioration. When the electron blocking layer is inserted, the carrier density in the vicinity of the interface between the light emitting layer and the electron blocking layer is increased and the light emission efficiency is improved. Since the improvement of the light emission efficiency means an increase of the light emission intensity with respect to the input power, the amount of current passing through the element is decreased in order to obtain the same amount of light, and as a result, the life characteristics are improved.

  These organic luminescent medium layers are usually subjected to a drying step for removing the solvent, optimizing the film quality, and optimizing the conductivity before laminating the next layer. In particular, since various solvents are used in the wet process, the drying conditions and drying methods are very important research subjects.

  The current drying method mainly uses a hot plate to dry the entire substrate from the substrate side, or uses a vacuum dryer and hot plate to dry the entire substrate under reduced pressure, or in the air like an oven dryer. There is a method of drying the entire substrate using convection and radiant heat.

  However, these drying methods all heat the entire substrate to heat the already laminated organic light emitting medium layer. For example, the glass transition temperature of the already laminated organic light emitting medium layer is newly laminated. If the organic light emitting medium layer is lower than the drying temperature condition, the film quality of the already laminated organic light emitting medium layer is changed and the desired characteristics cannot be obtained. Conversely, the drying temperature is changed to the organic light emitting medium already laminated. When the newly laminated organic light emitting medium layer is dried at a temperature lower than the glass transition temperature of the layer, there arises a problem that the desired properties cannot be obtained due to insufficient drying.

  In particular, the electron blocking layer is often a cross-linked molecule, and generally drying conditions higher than that of a normal organic light emitting medium layer are required for the purpose of both drying and chemical cross-linking reaction.

  Further, in the method of drying the entire substrate from the substrate side like a hot plate, there is a concern that the outermost surface is not sufficiently dried because heat is applied from the lower layer of the laminated organic light emitting medium layer.

  In addition, since the conductivity of the organic light emitting medium layer also changes depending on the heating temperature and heating time, there is a concern that the desired conductivity may change if new heat is applied to the already stacked organic light emitting medium layer. There is.

  Furthermore, the electronic state of the organic light-emitting medium layer interface is very complicated, and there is a concern that the characteristics are greatly affected by heating.

  By the way, in order to make a color panel using organic electroluminescence, it is necessary to coat the organic light emitting layer separately using organic light emitting materials having respective emission colors of red (R), green (G), and blue (B). Yes (see, for example, Patent Document 1).

  As a method of forming the organic light emitting medium layer by a wet process, techniques such as spin coating, die coating, ink jet, and printing are mainly used.

  Of the above methods, spin coating and die coating cannot be patterned by themselves. Inkjet printing and printing can be patterned, but there are limitations on the ink material, ink solvent, and viscosity, making it difficult to pattern stably. In particular, as the definition becomes higher, the color mixture of ink to adjacent pixels becomes more prominent, and accurate and stable patterning becomes more difficult.

  In the case of manufacturing a color panel as well as a wet process, it is necessary to pattern an electrode, and the patterned electrode has a problem that an electric field is concentrated on an end portion and a leak current is generated.

  Therefore, in general, when patterning is performed, a partition pattern is provided as a convex partition member in order to prevent these problems. The barrier rib pattern is formed by applying a photoresist to the substrate and using a normal photolithography process including exposure and development.

  On the other hand, the hole transport layer is generally formed by using a coating method such as a spin coating method or a die coating method, without applying patterning, and is generally applied to the entire part of the organic EL display panel that is involved in image formation by applying the entire surface. I came.

  This is because the film thickness of the hole transport layer is generally a thin film of 100 nm or less, and the current flowing in the thickness direction is overwhelmingly easier to flow than the current flowing in the lateral direction of the layer, so if the electrode is patterned, This is because leakage of current outside the pixel was said to be very small, but even if patterning for each pixel is unnecessary in the above application method, a place where an adhesive for sealing is applied, Since a film is also formed at the mounting location of the driver chip, it is necessary to wipe and remove unnecessary portions of the hole transport layer after the film formation, and not only the organic light emitting layer but also the hole transport layer on the pixel electrode. Forming the pattern only on the surface is very demanding in order to shorten the process and reduce the cost.

  As described above, even when the organic EL display device is manufactured, since the entire drying process heats the entire substrate, the organic light emitting medium layer that has already been laminated is also heated, resulting in the problems described above.

  In addition, when mass-producing display devices, the drying process greatly affects the tact time and becomes a rule of production.

Furthermore, the organic light emitting medium layer needs to be formed in a complicated pattern, which increases the restrictions on the partition walls, TFT electrodes, interfaces in each organic light emitting medium layer, and drying temperature.
JP-A-8-297204

  The present invention has been made to solve the above-described problems, and the object of the present invention is to provide a method for manufacturing an organic EL element that forms an organic light emitting medium layer, and all organic light emitting medium layers in a drying step. To provide a method and a display device for quickly producing a long-life and high-efficiency organic EL element in which damage to the light is suppressed, each pixel emits light uniformly, and no non-light emitting portion or current leakage occurs. .

  By the way, according to the study of the present inventor, by using the relief printing contact drying method for drying the organic light emitting medium layer, damage to all the organic light emitting medium layers in the drying process can be suppressed, and there is no defect or unevenness of the organic EL element. It has become possible to quickly provide a manufacturing method and a display device.

  The letterpress contact drying method is a method in which a metal relief plate attached to a plate cylinder is heated, and the plate projection is brought into contact with the substrate while the plate cylinder is rotated, followed by drying by heating.

The present invention has been made based on such knowledge, and the invention according to claim 1 includes a first electrode, a second electrode provided to face the first electrode, and the first electrode. In the method of manufacturing an organic electroluminescent element including an organic light emitting medium layer including at least an organic light emitting layer between the electrode and the second electrode, at least one layer of the organic light emitting medium layer is dried by a relief contact drying method. This is a method for producing an organic electroluminescence element.
Invention of Claim 2 is a manufacturing method of the organic electroluminescent element of Claim 1 whose said organic light emitting medium layer is two or more layers.
Invention of Claim 3 is a manufacturing method of the organic electroluminescent element of Claim 1 or 2 with which the said organic light emitting medium layer contains the layer which consists of a bridge | crosslinking type material.
A fourth aspect of the present invention is the method for manufacturing an organic electroluminescent element according to any one of the first to third aspects, wherein the organic light emitting medium layer is formed by a wet process.
The invention according to claim 5 is the method for producing an organic electroluminescence element according to claim 4, wherein the wet process is a relief printing method.
The invention according to claim 6 is an organic electroluminescent element manufactured by the method for manufacturing an organic electroluminescent element according to any one of claims 1 to 5.
A seventh aspect of the present invention is a display device comprising the organic electroluminescence element according to the sixth aspect as a display element.

  According to the present invention, in drying the organic light emitting medium layer, it is possible to dry the outermost layer and the outermost surface without applying heat to the already formed organic light emitting medium layer, and to optimize all the organic light emitting medium layers. A long-life organic EL element that can maintain a uniform film quality, emits light uniformly in each pixel, and does not generate non-light emitting portions or current leakage, and a display device using the same can be easily, efficiently, and quickly Can be provided.

  One embodiment of the present invention will be described by taking as an example the case of producing a passive matrix type organic EL display panel. However, the present invention is not limited to these. A schematic diagram of a cross section of the organic EL display panel of the present invention is shown in FIG.

  The organic EL element in the organic EL display panel is formed on the translucent substrate 1. As the translucent substrate 1, a glass substrate or a plastic film or sheet can be used. If a plastic film is used, a polymer EL element can be produced by winding, and a display panel can be provided at a low cost. As the plastic, for example, polyethylene terephthalate, polypropylene, cycloolefin polymer, polyamide, polyethersulfone, polymethyl methacrylate, polycarbonate and the like can be used. Further, these films are barrier layers made of metal oxides such as silicon oxide, which exhibit water vapor barrier properties and oxygen barrier properties, oxynitrides such as silicon nitride, polyvinylidene chloride, polyvinyl chloride, saponified ethylene-vinyl acetate copolymers. Is provided as necessary.

  A pixel electrode 2 patterned as an anode is provided on the translucent substrate. As the material of the pixel electrode 2, transparent electrode materials such as ITO (indium tin composite oxide), IZO (indium zinc composite oxide), tin oxide, zinc oxide, indium oxide, and aluminum oxide composite oxide can be used. ITO is preferred because of its low resistance, solvent resistance and transparency. ITO is formed on the light-transmitting substrate by sputtering, and is patterned by photolithography to form line-shaped pixel electrodes 2.

  After the line-shaped pixel electrode 2 is formed, a partition wall 3 is formed by a photolithography method using a photosensitive material between adjacent pixel electrodes. More specifically, it includes at least a step of applying a photosensitive resin composition to a substrate, a step of pattern exposure and development to form a partition pattern, and a step of applying light irradiation to the partition pattern to make it hydrophilic. .

  The photosensitive material for forming the partition wall may be either a positive resist or a negative resist, and may be a commercially available one, but it must have insulating properties. If the partition wall does not have sufficient insulation, a current flows to the adjacent pixel electrode through the partition wall, resulting in a display defect. Specific examples include polyimide, acrylic resin, novolac resin, and fluorene, but the present invention is not limited thereto. Further, for the purpose of improving the display quality of the organic EL element, a light shielding material may be included in the photosensitive material.

  The photosensitive resin forming the partition walls 3 is applied using a known coating method such as a spin coater, bar coater, roll coater, die coater, or gravure coater.

  Next, in the step of pattern exposure and development to form a partition wall pattern, a partition wall pattern having a step shape can be formed by a conventionally known exposure and development method. In the case where the organic light emitting medium layer is a two-layer system of a hole transport layer and an organic light emitting layer, it is more preferably two steps, but this is not restrictive.

  The partition wall 3 in the present invention desirably has a thickness in the range of 0.5 μm to 5.0 μm. Further, the thickness of the first step needs to be greater than or equal to the thickness of the hole transport layer and less than or equal to the thickness of the organic light emitting layer, and the thickness of the second step needs to be greater than or equal to the thickness of the organic light emitting layer. By providing the partition wall 3 between adjacent pixel electrodes, it is possible to suppress the spread of the hole transport ink printed on each pixel electrode and to prevent occurrence of a short circuit from the edge of the transparent conductive film. If the partition walls are too low, the effect of preventing a short circuit may not be obtained, so care must be taken.

  After the partition walls are formed, the hole transport layer 4 is formed. In the present invention, it is preferable to use a water-based hole transport ink having a pH of 3 or less as the hole transport ink for forming the hole transport layer 4. This is because the hole transport ink is likely to be precipitated during printing in the dissolution type.

  The aqueous dispersion type hole transport ink is often acidic, but in the present invention, it is preferably used in an acidic state without being neutralized. This is because neutralization may cause the ink stability to deteriorate and the hole transportability to deteriorate. Neutralization with an inorganic alkali or the like should be avoided because the ion content is contaminated and the life is deteriorated.

These materials are dissolved or dispersed in a solvent to form a hole transport material ink, which is formed using a wet process, particularly a relief printing method. The volume resistivity of the formed hole transport layer is preferably 1 × 10 ⁶ Ω · cm or less from the viewpoint of light emission efficiency.

  Examples of the solvent that dissolves or disperses the hole transport material include toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, isopropanol, ethylene glycol, propylene glycol, polyethylene glycol, glycerin, ethyl acetate, and acetic acid. A mixed solvent composed of butyl, isopropyl acetate, water or the like can be raised, but in the present invention, it is preferable to be composed of water or a solvent that can be mixed with water at an arbitrary ratio.

  FIG. 2 shows a schematic diagram of a relief printing apparatus when pattern printing is performed by a relief printing method on a substrate to be printed on which a pixel electrode and a partition wall are formed with a hole transport ink made of a hole transport material. This manufacturing apparatus has a plate cylinder 18 on which an ink tank 10, an ink chamber 12, an anilox roll 14, and a plate 16 provided with convex portions are mounted. An organic luminescent ink diluted with a solvent is accommodated in the ink tank 10, and hole transport ink is fed into the ink chamber 12 from the ink tank 10. The anilox roll 14 is rotatably supported with respect to the ink supply part of the ink chamber 12.

  As the anilox roll 14 rotates, the ink layer 14a of the hole transport ink supplied to the anilox roll surface is formed with a uniform film thickness. This ink layer is transferred to the convex portion of the plate 16 mounted on the plate cylinder 18 that is driven to rotate in the vicinity of the anilox roll. On the flat table 20, the substrate to be printed 24 on which the transparent electrodes and the partition walls are formed is transported to a printing position by the convex portion of the plate 16 by a transport means (not shown). And the ink in the convex part of the plate 16 is printed on the substrate 24 to be printed, and if necessary, a hole transport layer is formed on the substrate to be printed through a drying process.

  The photosensitive resin relief plate used for this relief plate was a water development type. The photosensitive resin plate includes a solvent development type in which the developer used when developing the exposed resin plate is an organic solvent and a water development type in which the developer is water. The solvent development type tends to be resistant to water-based inks, and the water development type tends to be resistant to organic solvent-based inks. Any resin relief can be used.

  After the substrate 1 on which the partition walls 3 are formed as described above is fired, the process proceeds to the next step. Here, the condition for firing the partition walls 3 is preferably heating at 200 to 250 ° C. for 10 to 60 minutes. In this firing, the partition walls are completely cured, and sufficient resistance as an organic EL element can be obtained. Here, when the firing temperature is 200 ° C. or lower, the partition firing conditions are low, and there is a concern about problems such as uncured partition material. Moreover, since the temperature is too high at 250 ° C. or higher, there is a risk that the partition wall is thermally deteriorated. Further, if the time is 10 minutes or less, the firing is short, so that the firing is insufficient.

  The hole transport layer 4 is formed by printing the hole transport ink on the substrate 1 on which the partition walls 3 baked as described above are formed by the above-described relief printing method.

  Here, a relief contact drying method is used as a method for firing the hole transport layer 4. FIG. 3 is a schematic view of a relief printing drying apparatus for pattern drying by a relief printing contact drying method on a substrate 31 to be dried on which a pixel electrode, a partition, and a hole transporting ink are placed. is there.

  In the relief printing contact drying method, a current is applied to the surface resistor 42 attached to the plate cylinder 41 to heat the metal relief plate 43 using metal heat conduction, and the plate projection 41 is brought into contact with the substrate while rotating the plate cylinder 41. In this method, only the desired position is heated and dried. It is preferable to use copper having high thermal conductivity for the metal plate. In this firing, the hole transport layer can be fired without applying heat to the partition walls.

  After the hole transport layer 4 is formed, the electron block ink is printed by the above-described relief printing method to form the electron block layer 5. The electron blocking layer is a layer for blocking electrons in order to prevent electrons injected from the cathode into the organic light emitting layer 6 from passing through the anode as it is, and is composed of an electron blocking material.

  Examples of the electron blocking material include poly (N-vinylcarbazole) (hereinafter also referred to as PVK), poly (para-phenylene vinylene), carbazole biphenyl (hereinafter also referred to as CBP), N, N′-diphenyl-N, N. '-Bis (1-naphthyl) -1,1'-biphenyl-4,4'-diamine (hereinafter also referred to as NPD), N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1 , 1′-biphenyl-4,4′-diamine (hereinafter also referred to as TPD), 4,4′-bis (10-phenothiazinyl) biphenyl, 2,4,6-triphenyl-1,3,5-triazole , Polyfluorene derivatives, copolymers of triphenylamine and fluorene, and the like.

  After the electronic block layer 5 is formed, it is dried using a relief printing contact drying method. In this firing, the electron blocking layer can be fired without applying heat to the hole transport layer.

  After the formation of the electron blocking layer 5, the organic light emitting layer 6 is formed. The organic light emitting layer 6 is a layer that emits light by passing an electric current, and the organic light emitting material forming the organic light emitting layer is, for example, a coumarin type, a perylene type, a pyran type, an anthrone type, a porphyrene type, a quinacridone type, N, N Dispersed luminescent dyes such as' -dialkyl-substituted quinacridone, naphthalimide, N, N'-diaryl-substituted pyrrolopyrrole, iridium complex, etc. in polymers such as polystyrene, polymethylmethacrylate, polyvinylcarbazole, , Polyarylene-based, polyarylene vinylene-based, and polyfluorene-based polymer materials.

  These organic light emitting materials are dissolved or stably dispersed in a solvent to form an organic light emitting ink. Examples of the solvent for dissolving or dispersing the organic light-emitting material include toluene, xylene, acetone, anisole, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, or a mixed solvent thereof. Among these, aromatic organic solvents such as toluene, xylene, and anisole are preferable from the viewpoint of solubility of the organic light emitting material. Moreover, antioxidant, a viscosity modifier, a ultraviolet absorber, etc. may be added to organic luminescent ink as needed.

  As a method for forming the organic light emitting layer 6, it is possible to form a pattern by an ink jet method, an intaglio offset printing method, a letterpress reverse offset printing method, or the like in addition to the letterpress printing method. In addition, when using the letterpress printing method, a resin letterpress suitable for an organic light-emitting ink can be used, and among these, a water development type photosensitive resin letterpress is preferred.

  After the organic light emitting layer 6 is formed, it is dried using a relief printing contact drying method. In this firing, the organic light emitting layer can be fired without applying heat to the electronic block layer. As described above, the present invention is particularly effective when the organic light emitting medium layer has two or more layers and when the organic light emitting medium layer includes a layer made of a crosslinkable material.

  The organic light emitting medium layer can be formed in the air, in a nitrogen atmosphere, or in a vacuum. When performed in the air, the time for adjusting the degree of vacuum can be saved.

  After the organic light emitting layer 6 is formed, the cathode layer 7 is formed in a line pattern orthogonal to the pixel electrode line pattern. As the material of the cathode layer 7, a material according to the light emitting characteristics of the organic light emitting layer can be used. For example, a simple metal such as lithium, magnesium, calcium, ytterbium or aluminum or a stable metal such as gold or silver can be used. An alloy etc. are mentioned. Alternatively, a conductive oxide such as indium, zinc, or tin can be used. Examples of the method for forming the cathode layer include a method using a vacuum vapor deposition method using a mask.

  The organic EL device of the present invention has a structure in which a hole transport layer and an organic light emitting layer are laminated from the anode layer side between a pixel electrode which is an anode and a cathode layer. In addition to the transport layer and the organic light emitting layer, a layered structure in which layers such as a hole blocking layer, an electron transport layer, and an electron injection layer are selected as necessary can be employed. Moreover, when forming these layers, the formation method similar to the above-mentioned organic light emitting medium layer can be used.

  In the letterpress contact drying method, the heating temperature of the metal letterpress 43 is appropriately determined depending on the components used in each layer, but is preferably lower than the glass transition temperature of each component, for example, 100 ° C to 200 ° C. The drying time is, for example, 10 to 300 seconds.

  Finally, in order to protect these organic EL constituents from external oxygen and moisture, a glass cap 8 and an adhesive 9 are hermetically sealed to obtain an organic EL display panel. Moreover, when a translucent board | substrate has flexibility, you may seal using a sealing agent and a flexible film.

  EXAMPLES Hereinafter, although an Example and a comparative example further demonstrate this invention, this invention is not restrict | limited to the following example.

Example 1
An ITO (indium-tin oxide) thin film is formed on a 1.8-inch sized glass substrate by sputtering, and the ITO film is patterned by photolithography and etching with an acid solution to form pixel electrodes. did. The line pattern of the pixel electrode was a pattern in which a line width of 136 μm, a space of 30 μm, and 192 lines were formed in about 32 mm square.

  Next, the partition was formed as follows. A positive photosensitive polyimide was spin-coated on the entire surface of the glass substrate on which the pixel electrodes were formed, and the height of the partition walls was 1.5 μm. The photosensitive material applied to the entire surface was exposed and developed by a photolithography method to form a partition having a line pattern between the pixel electrodes. Thereafter, the partition walls were baked in the atmosphere at 230 ° C. for 30 minutes.

  Next, 80 parts by weight as a hole transport ink and 20 parts by weight of ultrapure water were mixed and prepared to obtain an ink. It was 5.5 mPa * s when the viscosity was measured using this hole transport ink. A hole transport layer was formed between the partition walls using a relief printing method using the above ink. The composition of the hole transport ink is a 3% aqueous dispersion of polyethylene dioxythiophene: polystyrene sulfonic acid = 1: 20.

  After printing the hole transport layer, the hole transport layer was baked in the atmosphere at 130 ° C. for 10 minutes using a hot plate to form a hole transport layer. The film thickness of the hole transport layer at this time was 50 nm. The patterning state was confirmed with respect to the formed positive hole transport layer.

  Next, an electron block ink in which a polyfluorene derivative, which is an electron block material, is dissolved in toluene to a concentration of 0.4% is used, and electrons are aligned with the line pattern directly above the pixel electrode sandwiched between the partition walls. The block layer was printed by a relief printing method.

  After printing the electronic block layer, the electronic block layer was dried by a letterpress contact drying method. The electron blocking layer was formed at a drying temperature of 200 ° C. and a rotation speed of 60 mm / s. At this time, the thickness of the electron blocking layer was 20 nm. The patterning state was confirmed with respect to the formed electronic block layer. As a result, it was confirmed that a flat film shape was obtained.

  Next, using an organic light emitting ink in which a polyphenylene vinylene derivative, which is an organic light emitting material, is dissolved in toluene to a concentration of 1%, an organic light emitting layer is formed in line with the line pattern directly above the pixel electrode sandwiched between the partition walls. Was printed by letterpress printing.

  After printing the organic light emitting layer, the organic light emitting layer was baked in the air at 130 ° C. for 10 minutes using a hot plate to form an organic light emitting layer. The thickness of the organic light emitting layer at this time was 80 nm. The patterning state was confirmed with respect to the formed organic light emitting layer.

  A cathode layer made of Ca and Al was formed thereon by mask vapor deposition using a resistance heating vapor deposition method in a line pattern orthogonal to the pixel electrode line pattern. Finally, in order to protect these organic EL constituents from external oxygen and moisture, they were hermetically sealed using a glass cap and an adhesive to produce an organic EL display panel.

  The manufacturing time required for this embodiment was 90 minutes.

  There are an anode-side extraction electrode and a cathode-side extraction electrode connected to each pixel electrode in the periphery of the display portion of the organic EL display panel, and the organic EL display panel obtained by connecting these to a power source The lighting display was confirmed, and the light emission state and light emission characteristics were checked.

As a result, 160 cd / ^{m 2} brightness at 6V, also the brightness half time at an initial luminance 400 cd / ^{m 2} is 1600 hours, high luminous efficiency, high emission luminance, the resulting display characteristics of long life. Furthermore, as a result of an accelerated test in a constant temperature and high humidity environment at a temperature of 50 ° C. and a humidity of 90%, a dark spot was found on the light emitting surface in 5000 hours.

Example 2
In Example 1, after printing the hole transport layer, the hole transport layer was dried by a relief printing contact drying method. The hole transport layer was formed at a drying temperature of 130 ° C. and a rotation speed of 130 mm / s. The film thickness of the hole transport layer at this time was 50 nm. The patterning state was confirmed with respect to the formed positive hole transport layer. As a result, it was confirmed that a flat film shape was obtained. Other than that was produced similarly to Example 1.

  The manufacturing time required for this embodiment was 70 minutes.

  There are an anode-side extraction electrode and a cathode-side extraction electrode connected to each pixel electrode in the periphery of the display portion of the organic EL display panel, and the organic EL display panel obtained by connecting these to a power source The lighting display was confirmed, and the light emission state and light emission characteristics were checked.

As a result, 200 cd / ^{m 2} brightness at 6V, also the brightness half time at an initial luminance 400 cd / ^{m 2} is 2000 hours, high luminous efficiency, high emission luminance, the resulting display characteristics of long life. Furthermore, as a result of an accelerated test in a constant temperature and high humidity environment at a temperature of 50 ° C. and a humidity of 90%, a dark spot was found on the light emitting surface in 6000 hours.

Example 3
In Example 2, after printing the hole transport layer, the organic light emitting layer was dried by a relief printing contact drying method. The organic light emitting layer was formed at a drying temperature of 130 ° C. and a rotation speed of 130 mm / s. At this time, the thickness of the hole transport layer was 50 nm. Other than that was produced like Example 2. FIG.

  The manufacturing time required for this embodiment was 60 minutes.

  There are an anode-side extraction electrode and a cathode-side extraction electrode connected to each pixel electrode in the periphery of the display portion of the organic EL display panel, and the organic EL display panel obtained by connecting these to a power source The lighting display was confirmed, and the light emission state and light emission characteristics were checked.

As a result, 220 cd / ^{m 2} brightness at 6V, also the brightness half time at an initial luminance 400 cd / ^{m 2} is 2500 hours, high luminous efficiency, high emission luminance, the resulting display characteristics of long life. Furthermore, as a result of an accelerated test in a constant temperature and high humidity environment with a temperature of 50 ° C. and a humidity of 90%, dark spots were found on the light emitting surface in 7000 hours.

Comparative Example 1
In Example 1, after printing the electron block layer, the electron block layer was baked in the air at 200 ° C. for 10 minutes using a hot plate to form the electron block layer. The film thickness of the hole transport layer at this time was 20 nm. The patterning state was confirmed with respect to the formed positive hole transport layer.

  The manufacturing time required for this embodiment was 120 minutes.

  There are an anode-side extraction electrode and a cathode-side extraction electrode connected to each pixel electrode in the periphery of the display portion of the organic EL display panel, and the organic EL display panel obtained by connecting these to a power source The lighting display was confirmed, and the light emission state and light emission characteristics were checked.

As a result, it was possible to obtain display characteristics of high luminous efficiency, high luminous luminance, and long life with luminance of 6 VDC and 100 cd / m ² at an initial luminance of 400 cd / m ² and a luminance half-life of 1200 hours. Furthermore, as a result of an accelerated test in a constant temperature and high humidity environment with a temperature of 50 ° C. and a humidity of 90%, dark spots were found on the light emitting surface in 2000 hours.

It is a schematic diagram of the cross section of the organic electroluminescence display panel in embodiment of this invention. It is the schematic of the relief printing apparatus in embodiment of this invention. It is the schematic of the relief printing drying apparatus in embodiment of this invention.

Explanation of symbols

1: translucent substrate 2: pixel electrode 3: partition wall 4: hole transport layer 5: electron blocking layer 6: organic light emitting layer 7: cathode layer 8: glass cap 9: adhesive 10: ink tank 12: ink chamber 14 : Anilox roll 14a: Ink layer 16: Plate 18: Plate cylinder 20: Flat table 24: Printed substrate 30: Flat plate 31: Substrate to be dried 41: Plate cylinder 42: Surface resistor 43: Metal relief plate

Claims (7)

  Organic electroluminescence comprising a first electrode, a second electrode provided to face the first electrode, and an organic light emitting medium layer including at least an organic light emitting layer between the first electrode and the second electrode In the manufacturing method of an element, at least 1 layer of the said organic light emitting medium layer is dried by the relief printing contact drying method, The manufacturing method of the organic electroluminescent element characterized by the above-mentioned.   The method of manufacturing an organic electroluminescent element according to claim 1, wherein the organic light emitting medium layer has two or more layers.   3. The method of manufacturing an organic electroluminescence element according to claim 1, wherein the organic light emitting medium layer includes a layer made of a cross-linkable material.   The method for manufacturing an organic electroluminescent element according to claim 1, wherein the organic light emitting medium layer is formed by a wet process.   The method of manufacturing an organic electroluminescent element according to claim 4, wherein the wet process is a relief printing method.   An organic electroluminescent element manufactured by the method for manufacturing an organic electroluminescent element according to claim 1.   A display device comprising the organic electroluminescence element according to claim 6 as a display element.

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